// SPDX-License-Identifier: GPL-2.0
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/*
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* n_gsm.c GSM 0710 tty multiplexor
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* Copyright (c) 2009/10 Intel Corporation
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*
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* * THIS IS A DEVELOPMENT SNAPSHOT IT IS NOT A FINAL RELEASE *
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*
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* TO DO:
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* Mostly done: ioctls for setting modes/timing
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* Partly done: hooks so you can pull off frames to non tty devs
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* Restart DLCI 0 when it closes ?
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* Improve the tx engine
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* Resolve tx side locking by adding a queue_head and routing
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* all control traffic via it
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* General tidy/document
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* Review the locking/move to refcounts more (mux now moved to an
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* alloc/free model ready)
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* Use newest tty open/close port helpers and install hooks
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* What to do about power functions ?
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* Termios setting and negotiation
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* Do we need a 'which mux are you' ioctl to correlate mux and tty sets
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*
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*/
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#include <linux/types.h>
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#include <linux/major.h>
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#include <linux/errno.h>
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#include <linux/signal.h>
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#include <linux/fcntl.h>
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#include <linux/sched/signal.h>
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#include <linux/interrupt.h>
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#include <linux/tty.h>
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#include <linux/ctype.h>
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#include <linux/mm.h>
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#include <linux/string.h>
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#include <linux/slab.h>
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#include <linux/poll.h>
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#include <linux/bitops.h>
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#include <linux/file.h>
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#include <linux/uaccess.h>
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#include <linux/module.h>
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#include <linux/timer.h>
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#include <linux/tty_flip.h>
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#include <linux/tty_driver.h>
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#include <linux/serial.h>
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#include <linux/kfifo.h>
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#include <linux/skbuff.h>
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#include <net/arp.h>
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#include <linux/ip.h>
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#include <linux/netdevice.h>
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#include <linux/etherdevice.h>
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#include <linux/gsmmux.h>
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#include "tty.h"
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static int debug;
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module_param(debug, int, 0600);
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/* Defaults: these are from the specification */
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#define T1 10 /* 100mS */
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#define T2 34 /* 333mS */
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#define N2 3 /* Retry 3 times */
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/* Use long timers for testing at low speed with debug on */
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#ifdef DEBUG_TIMING
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#define T1 100
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#define T2 200
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#endif
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/*
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* Semi-arbitrary buffer size limits. 0710 is normally run with 32-64 byte
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* limits so this is plenty
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*/
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#define MAX_MRU 1500
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#define MAX_MTU 1500
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/* SOF, ADDR, CTRL, LEN1, LEN2, ..., FCS, EOF */
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#define PROT_OVERHEAD 7
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#define GSM_NET_TX_TIMEOUT (HZ*10)
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/**
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* struct gsm_mux_net - network interface
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*
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* Created when net interface is initialized.
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*/
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struct gsm_mux_net {
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struct kref ref;
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struct gsm_dlci *dlci;
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};
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/*
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* Each block of data we have queued to go out is in the form of
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* a gsm_msg which holds everything we need in a link layer independent
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* format
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*/
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struct gsm_msg {
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struct list_head list;
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u8 addr; /* DLCI address + flags */
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u8 ctrl; /* Control byte + flags */
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unsigned int len; /* Length of data block (can be zero) */
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unsigned char *data; /* Points into buffer but not at the start */
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unsigned char buffer[];
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};
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enum gsm_dlci_state {
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DLCI_CLOSED,
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DLCI_OPENING, /* Sending SABM not seen UA */
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DLCI_OPEN, /* SABM/UA complete */
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DLCI_CLOSING, /* Sending DISC not seen UA/DM */
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};
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enum gsm_dlci_mode {
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DLCI_MODE_ABM, /* Normal Asynchronous Balanced Mode */
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DLCI_MODE_ADM, /* Asynchronous Disconnected Mode */
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};
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/*
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* Each active data link has a gsm_dlci structure associated which ties
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* the link layer to an optional tty (if the tty side is open). To avoid
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* complexity right now these are only ever freed up when the mux is
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* shut down.
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*
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* At the moment we don't free DLCI objects until the mux is torn down
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* this avoid object life time issues but might be worth review later.
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*/
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struct gsm_dlci {
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struct gsm_mux *gsm;
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int addr;
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enum gsm_dlci_state state;
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struct mutex mutex;
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/* Link layer */
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enum gsm_dlci_mode mode;
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spinlock_t lock; /* Protects the internal state */
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struct timer_list t1; /* Retransmit timer for SABM and UA */
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int retries;
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/* Uplink tty if active */
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struct tty_port port; /* The tty bound to this DLCI if there is one */
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struct kfifo fifo; /* Queue fifo for the DLCI */
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int adaption; /* Adaption layer in use */
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int prev_adaption;
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u32 modem_rx; /* Our incoming virtual modem lines */
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u32 modem_tx; /* Our outgoing modem lines */
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bool dead; /* Refuse re-open */
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/* Flow control */
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bool throttled; /* Private copy of throttle state */
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bool constipated; /* Throttle status for outgoing */
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/* Packetised I/O */
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struct sk_buff *skb; /* Frame being sent */
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struct sk_buff_head skb_list; /* Queued frames */
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/* Data handling callback */
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void (*data)(struct gsm_dlci *dlci, const u8 *data, int len);
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void (*prev_data)(struct gsm_dlci *dlci, const u8 *data, int len);
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struct net_device *net; /* network interface, if created */
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};
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/* DLCI 0, 62/63 are special or reserved see gsmtty_open */
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#define NUM_DLCI 64
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/*
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* DLCI 0 is used to pass control blocks out of band of the data
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* flow (and with a higher link priority). One command can be outstanding
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* at a time and we use this structure to manage them. They are created
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* and destroyed by the user context, and updated by the receive paths
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* and timers
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*/
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struct gsm_control {
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u8 cmd; /* Command we are issuing */
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u8 *data; /* Data for the command in case we retransmit */
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int len; /* Length of block for retransmission */
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int done; /* Done flag */
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int error; /* Error if any */
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};
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enum gsm_mux_state {
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GSM_SEARCH,
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GSM_START,
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GSM_ADDRESS,
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GSM_CONTROL,
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GSM_LEN,
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GSM_DATA,
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GSM_FCS,
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GSM_OVERRUN,
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GSM_LEN0,
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GSM_LEN1,
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GSM_SSOF,
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};
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/*
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* Each GSM mux we have is represented by this structure. If we are
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* operating as an ldisc then we use this structure as our ldisc
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* state. We need to sort out lifetimes and locking with respect
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* to the gsm mux array. For now we don't free DLCI objects that
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* have been instantiated until the mux itself is terminated.
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*
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* To consider further: tty open versus mux shutdown.
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*/
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struct gsm_mux {
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struct tty_struct *tty; /* The tty our ldisc is bound to */
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spinlock_t lock;
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struct mutex mutex;
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unsigned int num;
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struct kref ref;
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/* Events on the GSM channel */
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wait_queue_head_t event;
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/* Bits for GSM mode decoding */
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/* Framing Layer */
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unsigned char *buf;
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enum gsm_mux_state state;
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unsigned int len;
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unsigned int address;
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unsigned int count;
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bool escape;
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int encoding;
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u8 control;
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u8 fcs;
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u8 received_fcs;
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u8 *txframe; /* TX framing buffer */
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/* Method for the receiver side */
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void (*receive)(struct gsm_mux *gsm, u8 ch);
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/* Link Layer */
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unsigned int mru;
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unsigned int mtu;
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int initiator; /* Did we initiate connection */
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bool dead; /* Has the mux been shut down */
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struct gsm_dlci *dlci[NUM_DLCI];
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int old_c_iflag; /* termios c_iflag value before attach */
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bool constipated; /* Asked by remote to shut up */
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spinlock_t tx_lock;
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unsigned int tx_bytes; /* TX data outstanding */
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#define TX_THRESH_HI 8192
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#define TX_THRESH_LO 2048
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struct list_head tx_list; /* Pending data packets */
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/* Control messages */
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struct timer_list t2_timer; /* Retransmit timer for commands */
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int cretries; /* Command retry counter */
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struct gsm_control *pending_cmd;/* Our current pending command */
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spinlock_t control_lock; /* Protects the pending command */
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/* Configuration */
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int adaption; /* 1 or 2 supported */
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u8 ftype; /* UI or UIH */
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int t1, t2; /* Timers in 1/100th of a sec */
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int n2; /* Retry count */
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/* Statistics (not currently exposed) */
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unsigned long bad_fcs;
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unsigned long malformed;
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unsigned long io_error;
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unsigned long bad_size;
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unsigned long unsupported;
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};
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/*
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* Mux objects - needed so that we can translate a tty index into the
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* relevant mux and DLCI.
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*/
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#define MAX_MUX 4 /* 256 minors */
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static struct gsm_mux *gsm_mux[MAX_MUX]; /* GSM muxes */
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static spinlock_t gsm_mux_lock;
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static struct tty_driver *gsm_tty_driver;
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/*
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* This section of the driver logic implements the GSM encodings
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* both the basic and the 'advanced'. Reliable transport is not
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* supported.
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*/
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#define CR 0x02
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#define EA 0x01
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#define PF 0x10
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/* I is special: the rest are ..*/
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#define RR 0x01
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#define UI 0x03
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#define RNR 0x05
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#define REJ 0x09
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#define DM 0x0F
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#define SABM 0x2F
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#define DISC 0x43
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#define UA 0x63
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#define UIH 0xEF
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/* Channel commands */
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#define CMD_NSC 0x09
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#define CMD_TEST 0x11
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#define CMD_PSC 0x21
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#define CMD_RLS 0x29
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#define CMD_FCOFF 0x31
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#define CMD_PN 0x41
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#define CMD_RPN 0x49
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#define CMD_FCON 0x51
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#define CMD_CLD 0x61
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#define CMD_SNC 0x69
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#define CMD_MSC 0x71
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/* Virtual modem bits */
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#define MDM_FC 0x01
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#define MDM_RTC 0x02
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#define MDM_RTR 0x04
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#define MDM_IC 0x20
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#define MDM_DV 0x40
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#define GSM0_SOF 0xF9
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#define GSM1_SOF 0x7E
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#define GSM1_ESCAPE 0x7D
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#define GSM1_ESCAPE_BITS 0x20
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#define XON 0x11
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#define XOFF 0x13
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#define ISO_IEC_646_MASK 0x7F
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static const struct tty_port_operations gsm_port_ops;
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/*
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* CRC table for GSM 0710
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*/
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static const u8 gsm_fcs8[256] = {
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0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75,
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0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B,
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0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69,
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0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67,
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0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D,
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0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43,
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0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51,
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0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F,
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0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05,
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0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B,
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0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19,
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0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17,
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0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D,
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0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33,
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0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21,
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0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F,
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0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95,
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0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B,
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0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89,
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0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87,
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0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD,
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0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3,
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0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1,
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0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF,
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0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5,
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0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB,
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0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9,
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0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7,
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0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD,
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0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3,
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0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1,
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0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF
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};
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#define INIT_FCS 0xFF
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#define GOOD_FCS 0xCF
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static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len);
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/**
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* gsm_fcs_add - update FCS
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* @fcs: Current FCS
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* @c: Next data
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*
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* Update the FCS to include c. Uses the algorithm in the specification
|
* notes.
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*/
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static inline u8 gsm_fcs_add(u8 fcs, u8 c)
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{
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return gsm_fcs8[fcs ^ c];
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}
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/**
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* gsm_fcs_add_block - update FCS for a block
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* @fcs: Current FCS
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* @c: buffer of data
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* @len: length of buffer
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*
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* Update the FCS to include c. Uses the algorithm in the specification
|
* notes.
|
*/
|
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static inline u8 gsm_fcs_add_block(u8 fcs, u8 *c, int len)
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{
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while (len--)
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fcs = gsm_fcs8[fcs ^ *c++];
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return fcs;
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}
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/**
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* gsm_read_ea - read a byte into an EA
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* @val: variable holding value
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* @c: byte going into the EA
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*
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* Processes one byte of an EA. Updates the passed variable
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* and returns 1 if the EA is now completely read
|
*/
|
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static int gsm_read_ea(unsigned int *val, u8 c)
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{
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/* Add the next 7 bits into the value */
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*val <<= 7;
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*val |= c >> 1;
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/* Was this the last byte of the EA 1 = yes*/
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return c & EA;
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}
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/**
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* gsm_read_ea_val - read a value until EA
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* @val: variable holding value
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* @data: buffer of data
|
* @dlen: length of data
|
*
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* Processes an EA value. Updates the passed variable and
|
* returns the processed data length.
|
*/
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static unsigned int gsm_read_ea_val(unsigned int *val, const u8 *data, int dlen)
|
{
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unsigned int len = 0;
|
|
for (; dlen > 0; dlen--) {
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len++;
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if (gsm_read_ea(val, *data++))
|
break;
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}
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return len;
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}
|
|
/**
|
* gsm_encode_modem - encode modem data bits
|
* @dlci: DLCI to encode from
|
*
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* Returns the correct GSM encoded modem status bits (6 bit field) for
|
* the current status of the DLCI and attached tty object
|
*/
|
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static u8 gsm_encode_modem(const struct gsm_dlci *dlci)
|
{
|
u8 modembits = 0;
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/* FC is true flow control not modem bits */
|
if (dlci->throttled)
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modembits |= MDM_FC;
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if (dlci->modem_tx & TIOCM_DTR)
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modembits |= MDM_RTC;
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if (dlci->modem_tx & TIOCM_RTS)
|
modembits |= MDM_RTR;
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if (dlci->modem_tx & TIOCM_RI)
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modembits |= MDM_IC;
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if (dlci->modem_tx & TIOCM_CD || dlci->gsm->initiator)
|
modembits |= MDM_DV;
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return modembits;
|
}
|
|
/**
|
* gsm_print_packet - display a frame for debug
|
* @hdr: header to print before decode
|
* @addr: address EA from the frame
|
* @cr: C/R bit from the frame
|
* @control: control including PF bit
|
* @data: following data bytes
|
* @dlen: length of data
|
*
|
* Displays a packet in human readable format for debugging purposes. The
|
* style is based on amateur radio LAP-B dump display.
|
*/
|
|
static void gsm_print_packet(const char *hdr, int addr, int cr,
|
u8 control, const u8 *data, int dlen)
|
{
|
if (!(debug & 1))
|
return;
|
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pr_info("%s %d) %c: ", hdr, addr, "RC"[cr]);
|
|
switch (control & ~PF) {
|
case SABM:
|
pr_cont("SABM");
|
break;
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case UA:
|
pr_cont("UA");
|
break;
|
case DISC:
|
pr_cont("DISC");
|
break;
|
case DM:
|
pr_cont("DM");
|
break;
|
case UI:
|
pr_cont("UI");
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break;
|
case UIH:
|
pr_cont("UIH");
|
break;
|
default:
|
if (!(control & 0x01)) {
|
pr_cont("I N(S)%d N(R)%d",
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(control & 0x0E) >> 1, (control & 0xE0) >> 5);
|
} else switch (control & 0x0F) {
|
case RR:
|
pr_cont("RR(%d)", (control & 0xE0) >> 5);
|
break;
|
case RNR:
|
pr_cont("RNR(%d)", (control & 0xE0) >> 5);
|
break;
|
case REJ:
|
pr_cont("REJ(%d)", (control & 0xE0) >> 5);
|
break;
|
default:
|
pr_cont("[%02X]", control);
|
}
|
}
|
|
if (control & PF)
|
pr_cont("(P)");
|
else
|
pr_cont("(F)");
|
|
print_hex_dump_bytes("", DUMP_PREFIX_NONE, data, dlen);
|
}
|
|
|
/*
|
* Link level transmission side
|
*/
|
|
/**
|
* gsm_stuff_packet - bytestuff a packet
|
* @input: input buffer
|
* @output: output buffer
|
* @len: length of input
|
*
|
* Expand a buffer by bytestuffing it. The worst case size change
|
* is doubling and the caller is responsible for handing out
|
* suitable sized buffers.
|
*/
|
|
static int gsm_stuff_frame(const u8 *input, u8 *output, int len)
|
{
|
int olen = 0;
|
while (len--) {
|
if (*input == GSM1_SOF || *input == GSM1_ESCAPE
|
|| (*input & ISO_IEC_646_MASK) == XON
|
|| (*input & ISO_IEC_646_MASK) == XOFF) {
|
*output++ = GSM1_ESCAPE;
|
*output++ = *input++ ^ GSM1_ESCAPE_BITS;
|
olen++;
|
} else
|
*output++ = *input++;
|
olen++;
|
}
|
return olen;
|
}
|
|
/**
|
* gsm_send - send a control frame
|
* @gsm: our GSM mux
|
* @addr: address for control frame
|
* @cr: command/response bit
|
* @control: control byte including PF bit
|
*
|
* Format up and transmit a control frame. These do not go via the
|
* queueing logic as they should be transmitted ahead of data when
|
* they are needed.
|
*
|
* FIXME: Lock versus data TX path
|
*/
|
|
static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
|
{
|
int len;
|
u8 cbuf[10];
|
u8 ibuf[3];
|
|
switch (gsm->encoding) {
|
case 0:
|
cbuf[0] = GSM0_SOF;
|
cbuf[1] = (addr << 2) | (cr << 1) | EA;
|
cbuf[2] = control;
|
cbuf[3] = EA; /* Length of data = 0 */
|
cbuf[4] = 0xFF - gsm_fcs_add_block(INIT_FCS, cbuf + 1, 3);
|
cbuf[5] = GSM0_SOF;
|
len = 6;
|
break;
|
case 1:
|
case 2:
|
/* Control frame + packing (but not frame stuffing) in mode 1 */
|
ibuf[0] = (addr << 2) | (cr << 1) | EA;
|
ibuf[1] = control;
|
ibuf[2] = 0xFF - gsm_fcs_add_block(INIT_FCS, ibuf, 2);
|
/* Stuffing may double the size worst case */
|
len = gsm_stuff_frame(ibuf, cbuf + 1, 3);
|
/* Now add the SOF markers */
|
cbuf[0] = GSM1_SOF;
|
cbuf[len + 1] = GSM1_SOF;
|
/* FIXME: we can omit the lead one in many cases */
|
len += 2;
|
break;
|
default:
|
WARN_ON(1);
|
return;
|
}
|
gsmld_output(gsm, cbuf, len);
|
gsm_print_packet("-->", addr, cr, control, NULL, 0);
|
}
|
|
/**
|
* gsm_response - send a control response
|
* @gsm: our GSM mux
|
* @addr: address for control frame
|
* @control: control byte including PF bit
|
*
|
* Format up and transmit a link level response frame.
|
*/
|
|
static inline void gsm_response(struct gsm_mux *gsm, int addr, int control)
|
{
|
gsm_send(gsm, addr, 0, control);
|
}
|
|
/**
|
* gsm_command - send a control command
|
* @gsm: our GSM mux
|
* @addr: address for control frame
|
* @control: control byte including PF bit
|
*
|
* Format up and transmit a link level command frame.
|
*/
|
|
static inline void gsm_command(struct gsm_mux *gsm, int addr, int control)
|
{
|
gsm_send(gsm, addr, 1, control);
|
}
|
|
/* Data transmission */
|
|
#define HDR_LEN 6 /* ADDR CTRL [LEN.2] DATA FCS */
|
|
/**
|
* gsm_data_alloc - allocate data frame
|
* @gsm: GSM mux
|
* @addr: DLCI address
|
* @len: length excluding header and FCS
|
* @ctrl: control byte
|
*
|
* Allocate a new data buffer for sending frames with data. Space is left
|
* at the front for header bytes but that is treated as an implementation
|
* detail and not for the high level code to use
|
*/
|
|
static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len,
|
u8 ctrl)
|
{
|
struct gsm_msg *m = kmalloc(sizeof(struct gsm_msg) + len + HDR_LEN,
|
GFP_ATOMIC);
|
if (m == NULL)
|
return NULL;
|
m->data = m->buffer + HDR_LEN - 1; /* Allow for FCS */
|
m->len = len;
|
m->addr = addr;
|
m->ctrl = ctrl;
|
INIT_LIST_HEAD(&m->list);
|
return m;
|
}
|
|
/**
|
* gsm_is_flow_ctrl_msg - checks if flow control message
|
* @msg: message to check
|
*
|
* Returns true if the given message is a flow control command of the
|
* control channel. False is returned in any other case.
|
*/
|
static bool gsm_is_flow_ctrl_msg(struct gsm_msg *msg)
|
{
|
unsigned int cmd;
|
|
if (msg->addr > 0)
|
return false;
|
|
switch (msg->ctrl & ~PF) {
|
case UI:
|
case UIH:
|
cmd = 0;
|
if (gsm_read_ea_val(&cmd, msg->data + 2, msg->len - 2) < 1)
|
break;
|
switch (cmd & ~PF) {
|
case CMD_FCOFF:
|
case CMD_FCON:
|
return true;
|
}
|
break;
|
}
|
|
return false;
|
}
|
|
/**
|
* gsm_data_kick - poke the queue
|
* @gsm: GSM Mux
|
*
|
* The tty device has called us to indicate that room has appeared in
|
* the transmit queue. Ram more data into the pipe if we have any
|
* If we have been flow-stopped by a CMD_FCOFF, then we can only
|
* send messages on DLCI0 until CMD_FCON
|
*
|
* FIXME: lock against link layer control transmissions
|
*/
|
|
static void gsm_data_kick(struct gsm_mux *gsm, struct gsm_dlci *dlci)
|
{
|
struct gsm_msg *msg, *nmsg;
|
int len;
|
|
list_for_each_entry_safe(msg, nmsg, &gsm->tx_list, list) {
|
if (gsm->constipated && !gsm_is_flow_ctrl_msg(msg))
|
continue;
|
if (gsm->encoding != 0) {
|
gsm->txframe[0] = GSM1_SOF;
|
len = gsm_stuff_frame(msg->data,
|
gsm->txframe + 1, msg->len);
|
gsm->txframe[len + 1] = GSM1_SOF;
|
len += 2;
|
} else {
|
gsm->txframe[0] = GSM0_SOF;
|
memcpy(gsm->txframe + 1 , msg->data, msg->len);
|
gsm->txframe[msg->len + 1] = GSM0_SOF;
|
len = msg->len + 2;
|
}
|
|
if (debug & 4)
|
print_hex_dump_bytes("gsm_data_kick: ",
|
DUMP_PREFIX_OFFSET,
|
gsm->txframe, len);
|
if (gsmld_output(gsm, gsm->txframe, len) < 0)
|
break;
|
/* FIXME: Can eliminate one SOF in many more cases */
|
gsm->tx_bytes -= msg->len;
|
|
list_del(&msg->list);
|
kfree(msg);
|
|
if (dlci) {
|
tty_port_tty_wakeup(&dlci->port);
|
} else {
|
int i = 0;
|
|
for (i = 0; i < NUM_DLCI; i++)
|
if (gsm->dlci[i])
|
tty_port_tty_wakeup(&gsm->dlci[i]->port);
|
}
|
}
|
}
|
|
/**
|
* __gsm_data_queue - queue a UI or UIH frame
|
* @dlci: DLCI sending the data
|
* @msg: message queued
|
*
|
* Add data to the transmit queue and try and get stuff moving
|
* out of the mux tty if not already doing so. The Caller must hold
|
* the gsm tx lock.
|
*/
|
|
static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
|
{
|
struct gsm_mux *gsm = dlci->gsm;
|
u8 *dp = msg->data;
|
u8 *fcs = dp + msg->len;
|
|
/* Fill in the header */
|
if (gsm->encoding == 0) {
|
if (msg->len < 128)
|
*--dp = (msg->len << 1) | EA;
|
else {
|
*--dp = (msg->len >> 7); /* bits 7 - 15 */
|
*--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
|
}
|
}
|
|
*--dp = msg->ctrl;
|
if (gsm->initiator)
|
*--dp = (msg->addr << 2) | 2 | EA;
|
else
|
*--dp = (msg->addr << 2) | EA;
|
*fcs = gsm_fcs_add_block(INIT_FCS, dp , msg->data - dp);
|
/* Ugly protocol layering violation */
|
if (msg->ctrl == UI || msg->ctrl == (UI|PF))
|
*fcs = gsm_fcs_add_block(*fcs, msg->data, msg->len);
|
*fcs = 0xFF - *fcs;
|
|
gsm_print_packet("Q> ", msg->addr, gsm->initiator, msg->ctrl,
|
msg->data, msg->len);
|
|
/* Move the header back and adjust the length, also allow for the FCS
|
now tacked on the end */
|
msg->len += (msg->data - dp) + 1;
|
msg->data = dp;
|
|
/* Add to the actual output queue */
|
list_add_tail(&msg->list, &gsm->tx_list);
|
gsm->tx_bytes += msg->len;
|
gsm_data_kick(gsm, dlci);
|
}
|
|
/**
|
* gsm_data_queue - queue a UI or UIH frame
|
* @dlci: DLCI sending the data
|
* @msg: message queued
|
*
|
* Add data to the transmit queue and try and get stuff moving
|
* out of the mux tty if not already doing so. Take the
|
* the gsm tx lock and dlci lock.
|
*/
|
|
static void gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
|
{
|
unsigned long flags;
|
spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
|
__gsm_data_queue(dlci, msg);
|
spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
|
}
|
|
/**
|
* gsm_dlci_data_output - try and push data out of a DLCI
|
* @gsm: mux
|
* @dlci: the DLCI to pull data from
|
*
|
* Pull data from a DLCI and send it into the transmit queue if there
|
* is data. Keep to the MRU of the mux. This path handles the usual tty
|
* interface which is a byte stream with optional modem data.
|
*
|
* Caller must hold the tx_lock of the mux.
|
*/
|
|
static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci)
|
{
|
struct gsm_msg *msg;
|
u8 *dp;
|
int h, len, size;
|
|
/* for modem bits without break data */
|
h = ((dlci->adaption == 1) ? 0 : 1);
|
|
len = kfifo_len(&dlci->fifo);
|
if (len == 0)
|
return 0;
|
|
/* MTU/MRU count only the data bits but watch adaption mode */
|
if ((len + h) > gsm->mtu)
|
len = gsm->mtu - h;
|
|
size = len + h;
|
|
msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
|
/* FIXME: need a timer or something to kick this so it can't
|
* get stuck with no work outstanding and no buffer free
|
*/
|
if (!msg)
|
return -ENOMEM;
|
dp = msg->data;
|
switch (dlci->adaption) {
|
case 1: /* Unstructured */
|
break;
|
case 2: /* Unstructured with modem bits.
|
* Always one byte as we never send inline break data
|
*/
|
*dp++ = (gsm_encode_modem(dlci) << 1) | EA;
|
break;
|
default:
|
pr_err("%s: unsupported adaption %d\n", __func__,
|
dlci->adaption);
|
break;
|
}
|
|
WARN_ON(len != kfifo_out_locked(&dlci->fifo, dp, len,
|
&dlci->lock));
|
|
/* Notify upper layer about available send space. */
|
tty_port_tty_wakeup(&dlci->port);
|
|
__gsm_data_queue(dlci, msg);
|
/* Bytes of data we used up */
|
return size;
|
}
|
|
/**
|
* gsm_dlci_data_output_framed - try and push data out of a DLCI
|
* @gsm: mux
|
* @dlci: the DLCI to pull data from
|
*
|
* Pull data from a DLCI and send it into the transmit queue if there
|
* is data. Keep to the MRU of the mux. This path handles framed data
|
* queued as skbuffs to the DLCI.
|
*
|
* Caller must hold the tx_lock of the mux.
|
*/
|
|
static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
|
struct gsm_dlci *dlci)
|
{
|
struct gsm_msg *msg;
|
u8 *dp;
|
int len, size;
|
int last = 0, first = 0;
|
int overhead = 0;
|
|
/* One byte per frame is used for B/F flags */
|
if (dlci->adaption == 4)
|
overhead = 1;
|
|
/* dlci->skb is locked by tx_lock */
|
if (dlci->skb == NULL) {
|
dlci->skb = skb_dequeue_tail(&dlci->skb_list);
|
if (dlci->skb == NULL)
|
return 0;
|
first = 1;
|
}
|
len = dlci->skb->len + overhead;
|
|
/* MTU/MRU count only the data bits */
|
if (len > gsm->mtu) {
|
if (dlci->adaption == 3) {
|
/* Over long frame, bin it */
|
dev_kfree_skb_any(dlci->skb);
|
dlci->skb = NULL;
|
return 0;
|
}
|
len = gsm->mtu;
|
} else
|
last = 1;
|
|
size = len + overhead;
|
msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);
|
|
/* FIXME: need a timer or something to kick this so it can't
|
get stuck with no work outstanding and no buffer free */
|
if (msg == NULL) {
|
skb_queue_tail(&dlci->skb_list, dlci->skb);
|
dlci->skb = NULL;
|
return -ENOMEM;
|
}
|
dp = msg->data;
|
|
if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */
|
/* Flag byte to carry the start/end info */
|
*dp++ = last << 7 | first << 6 | 1; /* EA */
|
len--;
|
}
|
memcpy(dp, dlci->skb->data, len);
|
skb_pull(dlci->skb, len);
|
__gsm_data_queue(dlci, msg);
|
if (last) {
|
dev_kfree_skb_any(dlci->skb);
|
dlci->skb = NULL;
|
}
|
return size;
|
}
|
|
/**
|
* gsm_dlci_data_sweep - look for data to send
|
* @gsm: the GSM mux
|
*
|
* Sweep the GSM mux channels in priority order looking for ones with
|
* data to send. We could do with optimising this scan a bit. We aim
|
* to fill the queue totally or up to TX_THRESH_HI bytes. Once we hit
|
* TX_THRESH_LO we get called again
|
*
|
* FIXME: We should round robin between groups and in theory you can
|
* renegotiate DLCI priorities with optional stuff. Needs optimising.
|
*/
|
|
static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
|
{
|
int len;
|
/* Priority ordering: We should do priority with RR of the groups */
|
int i = 1;
|
|
while (i < NUM_DLCI) {
|
struct gsm_dlci *dlci;
|
|
if (gsm->tx_bytes > TX_THRESH_HI)
|
break;
|
dlci = gsm->dlci[i];
|
if (dlci == NULL || dlci->constipated) {
|
i++;
|
continue;
|
}
|
if (dlci->adaption < 3 && !dlci->net)
|
len = gsm_dlci_data_output(gsm, dlci);
|
else
|
len = gsm_dlci_data_output_framed(gsm, dlci);
|
if (len < 0)
|
break;
|
/* DLCI empty - try the next */
|
if (len == 0)
|
i++;
|
}
|
}
|
|
/**
|
* gsm_dlci_data_kick - transmit if possible
|
* @dlci: DLCI to kick
|
*
|
* Transmit data from this DLCI if the queue is empty. We can't rely on
|
* a tty wakeup except when we filled the pipe so we need to fire off
|
* new data ourselves in other cases.
|
*/
|
|
static void gsm_dlci_data_kick(struct gsm_dlci *dlci)
|
{
|
unsigned long flags;
|
int sweep;
|
|
if (dlci->constipated)
|
return;
|
|
spin_lock_irqsave(&dlci->gsm->tx_lock, flags);
|
/* If we have nothing running then we need to fire up */
|
sweep = (dlci->gsm->tx_bytes < TX_THRESH_LO);
|
if (dlci->gsm->tx_bytes == 0) {
|
if (dlci->net)
|
gsm_dlci_data_output_framed(dlci->gsm, dlci);
|
else
|
gsm_dlci_data_output(dlci->gsm, dlci);
|
}
|
if (sweep)
|
gsm_dlci_data_sweep(dlci->gsm);
|
spin_unlock_irqrestore(&dlci->gsm->tx_lock, flags);
|
}
|
|
/*
|
* Control message processing
|
*/
|
|
|
/**
|
* gsm_control_reply - send a response frame to a control
|
* @gsm: gsm channel
|
* @cmd: the command to use
|
* @data: data to follow encoded info
|
* @dlen: length of data
|
*
|
* Encode up and queue a UI/UIH frame containing our response.
|
*/
|
|
static void gsm_control_reply(struct gsm_mux *gsm, int cmd, const u8 *data,
|
int dlen)
|
{
|
struct gsm_msg *msg;
|
msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
|
if (msg == NULL)
|
return;
|
msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
|
msg->data[1] = (dlen << 1) | EA;
|
memcpy(msg->data + 2, data, dlen);
|
gsm_data_queue(gsm->dlci[0], msg);
|
}
|
|
/**
|
* gsm_process_modem - process received modem status
|
* @tty: virtual tty bound to the DLCI
|
* @dlci: DLCI to affect
|
* @modem: modem bits (full EA)
|
*
|
* Used when a modem control message or line state inline in adaption
|
* layer 2 is processed. Sort out the local modem state and throttles
|
*/
|
|
static void gsm_process_modem(struct tty_struct *tty, struct gsm_dlci *dlci,
|
u32 modem, int clen)
|
{
|
int mlines = 0;
|
u8 brk = 0;
|
int fc;
|
|
/* The modem status command can either contain one octet (v.24 signals)
|
or two octets (v.24 signals + break signals). The length field will
|
either be 2 or 3 respectively. This is specified in section
|
5.4.6.3.7 of the 27.010 mux spec. */
|
|
if (clen == 2)
|
modem = modem & 0x7f;
|
else {
|
brk = modem & 0x7f;
|
modem = (modem >> 7) & 0x7f;
|
}
|
|
/* Flow control/ready to communicate */
|
fc = (modem & MDM_FC) || !(modem & MDM_RTR);
|
if (fc && !dlci->constipated) {
|
/* Need to throttle our output on this device */
|
dlci->constipated = true;
|
} else if (!fc && dlci->constipated) {
|
dlci->constipated = false;
|
gsm_dlci_data_kick(dlci);
|
}
|
|
/* Map modem bits */
|
if (modem & MDM_RTC)
|
mlines |= TIOCM_DSR | TIOCM_DTR;
|
if (modem & MDM_RTR)
|
mlines |= TIOCM_RTS | TIOCM_CTS;
|
if (modem & MDM_IC)
|
mlines |= TIOCM_RI;
|
if (modem & MDM_DV)
|
mlines |= TIOCM_CD;
|
|
/* Carrier drop -> hangup */
|
if (tty) {
|
if ((mlines & TIOCM_CD) == 0 && (dlci->modem_rx & TIOCM_CD))
|
if (!C_CLOCAL(tty))
|
tty_hangup(tty);
|
}
|
if (brk & 0x01)
|
tty_insert_flip_char(&dlci->port, 0, TTY_BREAK);
|
dlci->modem_rx = mlines;
|
}
|
|
/**
|
* gsm_control_modem - modem status received
|
* @gsm: GSM channel
|
* @data: data following command
|
* @clen: command length
|
*
|
* We have received a modem status control message. This is used by
|
* the GSM mux protocol to pass virtual modem line status and optionally
|
* to indicate break signals. Unpack it, convert to Linux representation
|
* and if need be stuff a break message down the tty.
|
*/
|
|
static void gsm_control_modem(struct gsm_mux *gsm, const u8 *data, int clen)
|
{
|
unsigned int addr = 0;
|
unsigned int modem = 0;
|
unsigned int brk = 0;
|
struct gsm_dlci *dlci;
|
int len = clen;
|
const u8 *dp = data;
|
struct tty_struct *tty;
|
|
while (gsm_read_ea(&addr, *dp++) == 0) {
|
len--;
|
if (len == 0)
|
return;
|
}
|
/* Must be at least one byte following the EA */
|
len--;
|
if (len <= 0)
|
return;
|
|
addr >>= 1;
|
/* Closed port, or invalid ? */
|
if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
|
return;
|
dlci = gsm->dlci[addr];
|
|
while (gsm_read_ea(&modem, *dp++) == 0) {
|
len--;
|
if (len == 0)
|
return;
|
}
|
len--;
|
if (len > 0) {
|
while (gsm_read_ea(&brk, *dp++) == 0) {
|
len--;
|
if (len == 0)
|
return;
|
}
|
modem <<= 7;
|
modem |= (brk & 0x7f);
|
}
|
tty = tty_port_tty_get(&dlci->port);
|
gsm_process_modem(tty, dlci, modem, clen);
|
if (tty) {
|
tty_wakeup(tty);
|
tty_kref_put(tty);
|
}
|
gsm_control_reply(gsm, CMD_MSC, data, clen);
|
}
|
|
/**
|
* gsm_control_rls - remote line status
|
* @gsm: GSM channel
|
* @data: data bytes
|
* @clen: data length
|
*
|
* The modem sends us a two byte message on the control channel whenever
|
* it wishes to send us an error state from the virtual link. Stuff
|
* this into the uplink tty if present
|
*/
|
|
static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen)
|
{
|
struct tty_port *port;
|
unsigned int addr = 0;
|
u8 bits;
|
int len = clen;
|
const u8 *dp = data;
|
|
while (gsm_read_ea(&addr, *dp++) == 0) {
|
len--;
|
if (len == 0)
|
return;
|
}
|
/* Must be at least one byte following ea */
|
len--;
|
if (len <= 0)
|
return;
|
addr >>= 1;
|
/* Closed port, or invalid ? */
|
if (addr == 0 || addr >= NUM_DLCI || gsm->dlci[addr] == NULL)
|
return;
|
/* No error ? */
|
bits = *dp;
|
if ((bits & 1) == 0)
|
return;
|
|
port = &gsm->dlci[addr]->port;
|
|
if (bits & 2)
|
tty_insert_flip_char(port, 0, TTY_OVERRUN);
|
if (bits & 4)
|
tty_insert_flip_char(port, 0, TTY_PARITY);
|
if (bits & 8)
|
tty_insert_flip_char(port, 0, TTY_FRAME);
|
|
tty_flip_buffer_push(port);
|
|
gsm_control_reply(gsm, CMD_RLS, data, clen);
|
}
|
|
static void gsm_dlci_begin_close(struct gsm_dlci *dlci);
|
|
/**
|
* gsm_control_message - DLCI 0 control processing
|
* @gsm: our GSM mux
|
* @command: the command EA
|
* @data: data beyond the command/length EAs
|
* @clen: length
|
*
|
* Input processor for control messages from the other end of the link.
|
* Processes the incoming request and queues a response frame or an
|
* NSC response if not supported
|
*/
|
|
static void gsm_control_message(struct gsm_mux *gsm, unsigned int command,
|
const u8 *data, int clen)
|
{
|
u8 buf[1];
|
unsigned long flags;
|
|
switch (command) {
|
case CMD_CLD: {
|
struct gsm_dlci *dlci = gsm->dlci[0];
|
/* Modem wishes to close down */
|
if (dlci) {
|
dlci->dead = true;
|
gsm->dead = true;
|
gsm_dlci_begin_close(dlci);
|
}
|
}
|
break;
|
case CMD_TEST:
|
/* Modem wishes to test, reply with the data */
|
gsm_control_reply(gsm, CMD_TEST, data, clen);
|
break;
|
case CMD_FCON:
|
/* Modem can accept data again */
|
gsm->constipated = false;
|
gsm_control_reply(gsm, CMD_FCON, NULL, 0);
|
/* Kick the link in case it is idling */
|
spin_lock_irqsave(&gsm->tx_lock, flags);
|
gsm_data_kick(gsm, NULL);
|
spin_unlock_irqrestore(&gsm->tx_lock, flags);
|
break;
|
case CMD_FCOFF:
|
/* Modem wants us to STFU */
|
gsm->constipated = true;
|
gsm_control_reply(gsm, CMD_FCOFF, NULL, 0);
|
break;
|
case CMD_MSC:
|
/* Out of band modem line change indicator for a DLCI */
|
gsm_control_modem(gsm, data, clen);
|
break;
|
case CMD_RLS:
|
/* Out of band error reception for a DLCI */
|
gsm_control_rls(gsm, data, clen);
|
break;
|
case CMD_PSC:
|
/* Modem wishes to enter power saving state */
|
gsm_control_reply(gsm, CMD_PSC, NULL, 0);
|
break;
|
/* Optional unsupported commands */
|
case CMD_PN: /* Parameter negotiation */
|
case CMD_RPN: /* Remote port negotiation */
|
case CMD_SNC: /* Service negotiation command */
|
default:
|
/* Reply to bad commands with an NSC */
|
buf[0] = command;
|
gsm_control_reply(gsm, CMD_NSC, buf, 1);
|
break;
|
}
|
}
|
|
/**
|
* gsm_control_response - process a response to our control
|
* @gsm: our GSM mux
|
* @command: the command (response) EA
|
* @data: data beyond the command/length EA
|
* @clen: length
|
*
|
* Process a response to an outstanding command. We only allow a single
|
* control message in flight so this is fairly easy. All the clean up
|
* is done by the caller, we just update the fields, flag it as done
|
* and return
|
*/
|
|
static void gsm_control_response(struct gsm_mux *gsm, unsigned int command,
|
const u8 *data, int clen)
|
{
|
struct gsm_control *ctrl;
|
unsigned long flags;
|
|
spin_lock_irqsave(&gsm->control_lock, flags);
|
|
ctrl = gsm->pending_cmd;
|
/* Does the reply match our command */
|
command |= 1;
|
if (ctrl != NULL && (command == ctrl->cmd || command == CMD_NSC)) {
|
/* Our command was replied to, kill the retry timer */
|
del_timer(&gsm->t2_timer);
|
gsm->pending_cmd = NULL;
|
/* Rejected by the other end */
|
if (command == CMD_NSC)
|
ctrl->error = -EOPNOTSUPP;
|
ctrl->done = 1;
|
wake_up(&gsm->event);
|
}
|
spin_unlock_irqrestore(&gsm->control_lock, flags);
|
}
|
|
/**
|
* gsm_control_transmit - send control packet
|
* @gsm: gsm mux
|
* @ctrl: frame to send
|
*
|
* Send out a pending control command (called under control lock)
|
*/
|
|
static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl)
|
{
|
struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 2, gsm->ftype);
|
if (msg == NULL)
|
return;
|
msg->data[0] = (ctrl->cmd << 1) | CR | EA; /* command */
|
msg->data[1] = (ctrl->len << 1) | EA;
|
memcpy(msg->data + 2, ctrl->data, ctrl->len);
|
gsm_data_queue(gsm->dlci[0], msg);
|
}
|
|
/**
|
* gsm_control_retransmit - retransmit a control frame
|
* @t: timer contained in our gsm object
|
*
|
* Called off the T2 timer expiry in order to retransmit control frames
|
* that have been lost in the system somewhere. The control_lock protects
|
* us from colliding with another sender or a receive completion event.
|
* In that situation the timer may still occur in a small window but
|
* gsm->pending_cmd will be NULL and we just let the timer expire.
|
*/
|
|
static void gsm_control_retransmit(struct timer_list *t)
|
{
|
struct gsm_mux *gsm = from_timer(gsm, t, t2_timer);
|
struct gsm_control *ctrl;
|
unsigned long flags;
|
spin_lock_irqsave(&gsm->control_lock, flags);
|
ctrl = gsm->pending_cmd;
|
if (ctrl) {
|
if (gsm->cretries == 0 || !gsm->dlci[0] || gsm->dlci[0]->dead) {
|
gsm->pending_cmd = NULL;
|
ctrl->error = -ETIMEDOUT;
|
ctrl->done = 1;
|
spin_unlock_irqrestore(&gsm->control_lock, flags);
|
wake_up(&gsm->event);
|
return;
|
}
|
gsm->cretries--;
|
gsm_control_transmit(gsm, ctrl);
|
mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
|
}
|
spin_unlock_irqrestore(&gsm->control_lock, flags);
|
}
|
|
/**
|
* gsm_control_send - send a control frame on DLCI 0
|
* @gsm: the GSM channel
|
* @command: command to send including CR bit
|
* @data: bytes of data (must be kmalloced)
|
* @clen: length of the block to send
|
*
|
* Queue and dispatch a control command. Only one command can be
|
* active at a time. In theory more can be outstanding but the matching
|
* gets really complicated so for now stick to one outstanding.
|
*/
|
|
static struct gsm_control *gsm_control_send(struct gsm_mux *gsm,
|
unsigned int command, u8 *data, int clen)
|
{
|
struct gsm_control *ctrl = kzalloc(sizeof(struct gsm_control),
|
GFP_ATOMIC);
|
unsigned long flags;
|
if (ctrl == NULL)
|
return NULL;
|
retry:
|
wait_event(gsm->event, gsm->pending_cmd == NULL);
|
spin_lock_irqsave(&gsm->control_lock, flags);
|
if (gsm->pending_cmd != NULL) {
|
spin_unlock_irqrestore(&gsm->control_lock, flags);
|
goto retry;
|
}
|
ctrl->cmd = command;
|
ctrl->data = data;
|
ctrl->len = clen;
|
gsm->pending_cmd = ctrl;
|
|
/* If DLCI0 is in ADM mode skip retries, it won't respond */
|
if (gsm->dlci[0]->mode == DLCI_MODE_ADM)
|
gsm->cretries = 0;
|
else
|
gsm->cretries = gsm->n2;
|
|
mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100);
|
gsm_control_transmit(gsm, ctrl);
|
spin_unlock_irqrestore(&gsm->control_lock, flags);
|
return ctrl;
|
}
|
|
/**
|
* gsm_control_wait - wait for a control to finish
|
* @gsm: GSM mux
|
* @control: control we are waiting on
|
*
|
* Waits for the control to complete or time out. Frees any used
|
* resources and returns 0 for success, or an error if the remote
|
* rejected or ignored the request.
|
*/
|
|
static int gsm_control_wait(struct gsm_mux *gsm, struct gsm_control *control)
|
{
|
int err;
|
wait_event(gsm->event, control->done == 1);
|
err = control->error;
|
kfree(control);
|
return err;
|
}
|
|
|
/*
|
* DLCI level handling: Needs krefs
|
*/
|
|
/*
|
* State transitions and timers
|
*/
|
|
/**
|
* gsm_dlci_close - a DLCI has closed
|
* @dlci: DLCI that closed
|
*
|
* Perform processing when moving a DLCI into closed state. If there
|
* is an attached tty this is hung up
|
*/
|
|
static void gsm_dlci_close(struct gsm_dlci *dlci)
|
{
|
unsigned long flags;
|
|
del_timer(&dlci->t1);
|
if (debug & 8)
|
pr_debug("DLCI %d goes closed.\n", dlci->addr);
|
dlci->state = DLCI_CLOSED;
|
/* Prevent us from sending data before the link is up again */
|
dlci->constipated = true;
|
if (dlci->addr != 0) {
|
tty_port_tty_hangup(&dlci->port, false);
|
spin_lock_irqsave(&dlci->lock, flags);
|
kfifo_reset(&dlci->fifo);
|
spin_unlock_irqrestore(&dlci->lock, flags);
|
/* Ensure that gsmtty_open() can return. */
|
tty_port_set_initialized(&dlci->port, 0);
|
wake_up_interruptible(&dlci->port.open_wait);
|
} else
|
dlci->gsm->dead = true;
|
wake_up(&dlci->gsm->event);
|
/* A DLCI 0 close is a MUX termination so we need to kick that
|
back to userspace somehow */
|
}
|
|
/**
|
* gsm_dlci_open - a DLCI has opened
|
* @dlci: DLCI that opened
|
*
|
* Perform processing when moving a DLCI into open state.
|
*/
|
|
static void gsm_dlci_open(struct gsm_dlci *dlci)
|
{
|
/* Note that SABM UA .. SABM UA first UA lost can mean that we go
|
open -> open */
|
del_timer(&dlci->t1);
|
/* This will let a tty open continue */
|
dlci->state = DLCI_OPEN;
|
dlci->constipated = false;
|
if (debug & 8)
|
pr_debug("DLCI %d goes open.\n", dlci->addr);
|
wake_up(&dlci->gsm->event);
|
}
|
|
/**
|
* gsm_dlci_t1 - T1 timer expiry
|
* @t: timer contained in the DLCI that opened
|
*
|
* The T1 timer handles retransmits of control frames (essentially of
|
* SABM and DISC). We resend the command until the retry count runs out
|
* in which case an opening port goes back to closed and a closing port
|
* is simply put into closed state (any further frames from the other
|
* end will get a DM response)
|
*
|
* Some control dlci can stay in ADM mode with other dlci working just
|
* fine. In that case we can just keep the control dlci open after the
|
* DLCI_OPENING retries time out.
|
*/
|
|
static void gsm_dlci_t1(struct timer_list *t)
|
{
|
struct gsm_dlci *dlci = from_timer(dlci, t, t1);
|
struct gsm_mux *gsm = dlci->gsm;
|
|
switch (dlci->state) {
|
case DLCI_OPENING:
|
if (dlci->retries) {
|
dlci->retries--;
|
gsm_command(dlci->gsm, dlci->addr, SABM|PF);
|
mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
|
} else if (!dlci->addr && gsm->control == (DM | PF)) {
|
if (debug & 8)
|
pr_info("DLCI %d opening in ADM mode.\n",
|
dlci->addr);
|
dlci->mode = DLCI_MODE_ADM;
|
gsm_dlci_open(dlci);
|
} else {
|
gsm_dlci_begin_close(dlci); /* prevent half open link */
|
}
|
|
break;
|
case DLCI_CLOSING:
|
if (dlci->retries) {
|
dlci->retries--;
|
gsm_command(dlci->gsm, dlci->addr, DISC|PF);
|
mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
|
} else
|
gsm_dlci_close(dlci);
|
break;
|
default:
|
pr_debug("%s: unhandled state: %d\n", __func__, dlci->state);
|
break;
|
}
|
}
|
|
/**
|
* gsm_dlci_begin_open - start channel open procedure
|
* @dlci: DLCI to open
|
*
|
* Commence opening a DLCI from the Linux side. We issue SABM messages
|
* to the modem which should then reply with a UA or ADM, at which point
|
* we will move into open state. Opening is done asynchronously with retry
|
* running off timers and the responses.
|
*/
|
|
static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
|
{
|
struct gsm_mux *gsm = dlci->gsm;
|
if (dlci->state == DLCI_OPEN || dlci->state == DLCI_OPENING)
|
return;
|
dlci->retries = gsm->n2;
|
dlci->state = DLCI_OPENING;
|
gsm_command(dlci->gsm, dlci->addr, SABM|PF);
|
mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
|
}
|
|
/**
|
* gsm_dlci_set_opening - change state to opening
|
* @dlci: DLCI to open
|
*
|
* Change internal state to wait for DLCI open from initiator side.
|
* We set off timers and responses upon reception of an SABM.
|
*/
|
static void gsm_dlci_set_opening(struct gsm_dlci *dlci)
|
{
|
switch (dlci->state) {
|
case DLCI_CLOSED:
|
case DLCI_CLOSING:
|
dlci->state = DLCI_OPENING;
|
break;
|
default:
|
break;
|
}
|
}
|
|
/**
|
* gsm_dlci_begin_close - start channel open procedure
|
* @dlci: DLCI to open
|
*
|
* Commence closing a DLCI from the Linux side. We issue DISC messages
|
* to the modem which should then reply with a UA, at which point we
|
* will move into closed state. Closing is done asynchronously with retry
|
* off timers. We may also receive a DM reply from the other end which
|
* indicates the channel was already closed.
|
*/
|
|
static void gsm_dlci_begin_close(struct gsm_dlci *dlci)
|
{
|
struct gsm_mux *gsm = dlci->gsm;
|
if (dlci->state == DLCI_CLOSED || dlci->state == DLCI_CLOSING)
|
return;
|
dlci->retries = gsm->n2;
|
dlci->state = DLCI_CLOSING;
|
gsm_command(dlci->gsm, dlci->addr, DISC|PF);
|
mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
|
}
|
|
/**
|
* gsm_dlci_data - data arrived
|
* @dlci: channel
|
* @data: block of bytes received
|
* @clen: length of received block
|
*
|
* A UI or UIH frame has arrived which contains data for a channel
|
* other than the control channel. If the relevant virtual tty is
|
* open we shovel the bits down it, if not we drop them.
|
*/
|
|
static void gsm_dlci_data(struct gsm_dlci *dlci, const u8 *data, int clen)
|
{
|
/* krefs .. */
|
struct tty_port *port = &dlci->port;
|
struct tty_struct *tty;
|
unsigned int modem = 0;
|
int len = clen;
|
|
if (debug & 16)
|
pr_debug("%d bytes for tty\n", len);
|
switch (dlci->adaption) {
|
/* Unsupported types */
|
case 4: /* Packetised interruptible data */
|
break;
|
case 3: /* Packetised uininterruptible voice/data */
|
break;
|
case 2: /* Asynchronous serial with line state in each frame */
|
while (gsm_read_ea(&modem, *data++) == 0) {
|
len--;
|
if (len == 0)
|
return;
|
}
|
tty = tty_port_tty_get(port);
|
if (tty) {
|
gsm_process_modem(tty, dlci, modem, clen);
|
tty_kref_put(tty);
|
}
|
fallthrough;
|
case 1: /* Line state will go via DLCI 0 controls only */
|
default:
|
tty_insert_flip_string(port, data, len);
|
tty_flip_buffer_push(port);
|
}
|
}
|
|
/**
|
* gsm_dlci_control - data arrived on control channel
|
* @dlci: channel
|
* @data: block of bytes received
|
* @len: length of received block
|
*
|
* A UI or UIH frame has arrived which contains data for DLCI 0 the
|
* control channel. This should contain a command EA followed by
|
* control data bytes. The command EA contains a command/response bit
|
* and we divide up the work accordingly.
|
*/
|
|
static void gsm_dlci_command(struct gsm_dlci *dlci, const u8 *data, int len)
|
{
|
/* See what command is involved */
|
unsigned int command = 0;
|
while (len-- > 0) {
|
if (gsm_read_ea(&command, *data++) == 1) {
|
int clen = *data++;
|
len--;
|
/* FIXME: this is properly an EA */
|
clen >>= 1;
|
/* Malformed command ? */
|
if (clen > len)
|
return;
|
if (command & 1)
|
gsm_control_message(dlci->gsm, command,
|
data, clen);
|
else
|
gsm_control_response(dlci->gsm, command,
|
data, clen);
|
return;
|
}
|
}
|
}
|
|
/*
|
* Allocate/Free DLCI channels
|
*/
|
|
/**
|
* gsm_dlci_alloc - allocate a DLCI
|
* @gsm: GSM mux
|
* @addr: address of the DLCI
|
*
|
* Allocate and install a new DLCI object into the GSM mux.
|
*
|
* FIXME: review locking races
|
*/
|
|
static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
|
{
|
struct gsm_dlci *dlci = kzalloc(sizeof(struct gsm_dlci), GFP_ATOMIC);
|
if (dlci == NULL)
|
return NULL;
|
spin_lock_init(&dlci->lock);
|
mutex_init(&dlci->mutex);
|
if (kfifo_alloc(&dlci->fifo, 4096, GFP_KERNEL) < 0) {
|
kfree(dlci);
|
return NULL;
|
}
|
|
skb_queue_head_init(&dlci->skb_list);
|
timer_setup(&dlci->t1, gsm_dlci_t1, 0);
|
tty_port_init(&dlci->port);
|
dlci->port.ops = &gsm_port_ops;
|
dlci->gsm = gsm;
|
dlci->addr = addr;
|
dlci->adaption = gsm->adaption;
|
dlci->state = DLCI_CLOSED;
|
if (addr) {
|
dlci->data = gsm_dlci_data;
|
/* Prevent us from sending data before the link is up */
|
dlci->constipated = true;
|
} else {
|
dlci->data = gsm_dlci_command;
|
}
|
gsm->dlci[addr] = dlci;
|
return dlci;
|
}
|
|
/**
|
* gsm_dlci_free - free DLCI
|
* @port: tty port for DLCI to free
|
*
|
* Free up a DLCI.
|
*
|
* Can sleep.
|
*/
|
static void gsm_dlci_free(struct tty_port *port)
|
{
|
struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
|
|
del_timer_sync(&dlci->t1);
|
dlci->gsm->dlci[dlci->addr] = NULL;
|
kfifo_free(&dlci->fifo);
|
while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
|
dev_kfree_skb(dlci->skb);
|
kfree(dlci);
|
}
|
|
static inline void dlci_get(struct gsm_dlci *dlci)
|
{
|
tty_port_get(&dlci->port);
|
}
|
|
static inline void dlci_put(struct gsm_dlci *dlci)
|
{
|
tty_port_put(&dlci->port);
|
}
|
|
static void gsm_destroy_network(struct gsm_dlci *dlci);
|
|
/**
|
* gsm_dlci_release - release DLCI
|
* @dlci: DLCI to destroy
|
*
|
* Release a DLCI. Actual free is deferred until either
|
* mux is closed or tty is closed - whichever is last.
|
*
|
* Can sleep.
|
*/
|
static void gsm_dlci_release(struct gsm_dlci *dlci)
|
{
|
struct tty_struct *tty = tty_port_tty_get(&dlci->port);
|
if (tty) {
|
mutex_lock(&dlci->mutex);
|
gsm_destroy_network(dlci);
|
mutex_unlock(&dlci->mutex);
|
|
/* We cannot use tty_hangup() because in tty_kref_put() the tty
|
* driver assumes that the hangup queue is free and reuses it to
|
* queue release_one_tty() -> NULL pointer panic in
|
* process_one_work().
|
*/
|
tty_vhangup(tty);
|
|
tty_port_tty_set(&dlci->port, NULL);
|
tty_kref_put(tty);
|
}
|
dlci->state = DLCI_CLOSED;
|
dlci_put(dlci);
|
}
|
|
/*
|
* LAPBish link layer logic
|
*/
|
|
/**
|
* gsm_queue - a GSM frame is ready to process
|
* @gsm: pointer to our gsm mux
|
*
|
* At this point in time a frame has arrived and been demangled from
|
* the line encoding. All the differences between the encodings have
|
* been handled below us and the frame is unpacked into the structures.
|
* The fcs holds the header FCS but any data FCS must be added here.
|
*/
|
|
static void gsm_queue(struct gsm_mux *gsm)
|
{
|
struct gsm_dlci *dlci;
|
u8 cr;
|
int address;
|
/* We have to sneak a look at the packet body to do the FCS.
|
A somewhat layering violation in the spec */
|
|
if ((gsm->control & ~PF) == UI)
|
gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len);
|
if (gsm->encoding == 0) {
|
/* WARNING: gsm->received_fcs is used for
|
gsm->encoding = 0 only.
|
In this case it contain the last piece of data
|
required to generate final CRC */
|
gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs);
|
}
|
if (gsm->fcs != GOOD_FCS) {
|
gsm->bad_fcs++;
|
if (debug & 4)
|
pr_debug("BAD FCS %02x\n", gsm->fcs);
|
return;
|
}
|
address = gsm->address >> 1;
|
if (address >= NUM_DLCI)
|
goto invalid;
|
|
cr = gsm->address & 1; /* C/R bit */
|
|
gsm_print_packet("<--", address, cr, gsm->control, gsm->buf, gsm->len);
|
|
cr ^= 1 - gsm->initiator; /* Flip so 1 always means command */
|
dlci = gsm->dlci[address];
|
|
switch (gsm->control) {
|
case SABM|PF:
|
if (cr == 0)
|
goto invalid;
|
if (dlci == NULL)
|
dlci = gsm_dlci_alloc(gsm, address);
|
if (dlci == NULL)
|
return;
|
if (dlci->dead)
|
gsm_response(gsm, address, DM);
|
else {
|
gsm_response(gsm, address, UA);
|
gsm_dlci_open(dlci);
|
}
|
break;
|
case DISC|PF:
|
if (cr == 0)
|
goto invalid;
|
if (dlci == NULL || dlci->state == DLCI_CLOSED) {
|
gsm_response(gsm, address, DM);
|
return;
|
}
|
/* Real close complete */
|
gsm_response(gsm, address, UA);
|
gsm_dlci_close(dlci);
|
break;
|
case UA|PF:
|
if (cr == 0 || dlci == NULL)
|
break;
|
switch (dlci->state) {
|
case DLCI_CLOSING:
|
gsm_dlci_close(dlci);
|
break;
|
case DLCI_OPENING:
|
gsm_dlci_open(dlci);
|
break;
|
default:
|
pr_debug("%s: unhandled state: %d\n", __func__,
|
dlci->state);
|
break;
|
}
|
break;
|
case DM: /* DM can be valid unsolicited */
|
case DM|PF:
|
if (cr)
|
goto invalid;
|
if (dlci == NULL)
|
return;
|
gsm_dlci_close(dlci);
|
break;
|
case UI:
|
case UI|PF:
|
case UIH:
|
case UIH|PF:
|
#if 0
|
if (cr)
|
goto invalid;
|
#endif
|
if (dlci == NULL || dlci->state != DLCI_OPEN) {
|
gsm_response(gsm, address, DM|PF);
|
return;
|
}
|
dlci->data(dlci, gsm->buf, gsm->len);
|
break;
|
default:
|
goto invalid;
|
}
|
return;
|
invalid:
|
gsm->malformed++;
|
return;
|
}
|
|
|
/**
|
* gsm0_receive - perform processing for non-transparency
|
* @gsm: gsm data for this ldisc instance
|
* @c: character
|
*
|
* Receive bytes in gsm mode 0
|
*/
|
|
static void gsm0_receive(struct gsm_mux *gsm, unsigned char c)
|
{
|
unsigned int len;
|
|
switch (gsm->state) {
|
case GSM_SEARCH: /* SOF marker */
|
if (c == GSM0_SOF) {
|
gsm->state = GSM_ADDRESS;
|
gsm->address = 0;
|
gsm->len = 0;
|
gsm->fcs = INIT_FCS;
|
}
|
break;
|
case GSM_ADDRESS: /* Address EA */
|
gsm->fcs = gsm_fcs_add(gsm->fcs, c);
|
if (gsm_read_ea(&gsm->address, c))
|
gsm->state = GSM_CONTROL;
|
break;
|
case GSM_CONTROL: /* Control Byte */
|
gsm->fcs = gsm_fcs_add(gsm->fcs, c);
|
gsm->control = c;
|
gsm->state = GSM_LEN0;
|
break;
|
case GSM_LEN0: /* Length EA */
|
gsm->fcs = gsm_fcs_add(gsm->fcs, c);
|
if (gsm_read_ea(&gsm->len, c)) {
|
if (gsm->len > gsm->mru) {
|
gsm->bad_size++;
|
gsm->state = GSM_SEARCH;
|
break;
|
}
|
gsm->count = 0;
|
if (!gsm->len)
|
gsm->state = GSM_FCS;
|
else
|
gsm->state = GSM_DATA;
|
break;
|
}
|
gsm->state = GSM_LEN1;
|
break;
|
case GSM_LEN1:
|
gsm->fcs = gsm_fcs_add(gsm->fcs, c);
|
len = c;
|
gsm->len |= len << 7;
|
if (gsm->len > gsm->mru) {
|
gsm->bad_size++;
|
gsm->state = GSM_SEARCH;
|
break;
|
}
|
gsm->count = 0;
|
if (!gsm->len)
|
gsm->state = GSM_FCS;
|
else
|
gsm->state = GSM_DATA;
|
break;
|
case GSM_DATA: /* Data */
|
gsm->buf[gsm->count++] = c;
|
if (gsm->count == gsm->len)
|
gsm->state = GSM_FCS;
|
break;
|
case GSM_FCS: /* FCS follows the packet */
|
gsm->received_fcs = c;
|
gsm_queue(gsm);
|
gsm->state = GSM_SSOF;
|
break;
|
case GSM_SSOF:
|
if (c == GSM0_SOF) {
|
gsm->state = GSM_SEARCH;
|
break;
|
}
|
break;
|
default:
|
pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
|
break;
|
}
|
}
|
|
/**
|
* gsm1_receive - perform processing for non-transparency
|
* @gsm: gsm data for this ldisc instance
|
* @c: character
|
*
|
* Receive bytes in mode 1 (Advanced option)
|
*/
|
|
static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
|
{
|
/* handle XON/XOFF */
|
if ((c & ISO_IEC_646_MASK) == XON) {
|
gsm->constipated = true;
|
return;
|
} else if ((c & ISO_IEC_646_MASK) == XOFF) {
|
gsm->constipated = false;
|
/* Kick the link in case it is idling */
|
gsm_data_kick(gsm, NULL);
|
return;
|
}
|
if (c == GSM1_SOF) {
|
/* EOF is only valid in frame if we have got to the data state
|
and received at least one byte (the FCS) */
|
if (gsm->state == GSM_DATA && gsm->count) {
|
/* Extract the FCS */
|
gsm->count--;
|
gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
|
gsm->len = gsm->count;
|
gsm_queue(gsm);
|
gsm->state = GSM_START;
|
return;
|
}
|
/* Any partial frame was a runt so go back to start */
|
if (gsm->state != GSM_START) {
|
if (gsm->state != GSM_SEARCH)
|
gsm->malformed++;
|
gsm->state = GSM_START;
|
}
|
/* A SOF in GSM_START means we are still reading idling or
|
framing bytes */
|
return;
|
}
|
|
if (c == GSM1_ESCAPE) {
|
gsm->escape = true;
|
return;
|
}
|
|
/* Only an unescaped SOF gets us out of GSM search */
|
if (gsm->state == GSM_SEARCH)
|
return;
|
|
if (gsm->escape) {
|
c ^= GSM1_ESCAPE_BITS;
|
gsm->escape = false;
|
}
|
switch (gsm->state) {
|
case GSM_START: /* First byte after SOF */
|
gsm->address = 0;
|
gsm->state = GSM_ADDRESS;
|
gsm->fcs = INIT_FCS;
|
fallthrough;
|
case GSM_ADDRESS: /* Address continuation */
|
gsm->fcs = gsm_fcs_add(gsm->fcs, c);
|
if (gsm_read_ea(&gsm->address, c))
|
gsm->state = GSM_CONTROL;
|
break;
|
case GSM_CONTROL: /* Control Byte */
|
gsm->fcs = gsm_fcs_add(gsm->fcs, c);
|
gsm->control = c;
|
gsm->count = 0;
|
gsm->state = GSM_DATA;
|
break;
|
case GSM_DATA: /* Data */
|
if (gsm->count > gsm->mru) { /* Allow one for the FCS */
|
gsm->state = GSM_OVERRUN;
|
gsm->bad_size++;
|
} else
|
gsm->buf[gsm->count++] = c;
|
break;
|
case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
|
break;
|
default:
|
pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
|
break;
|
}
|
}
|
|
/**
|
* gsm_error - handle tty error
|
* @gsm: ldisc data
|
* @data: byte received (may be invalid)
|
* @flag: error received
|
*
|
* Handle an error in the receipt of data for a frame. Currently we just
|
* go back to hunting for a SOF.
|
*
|
* FIXME: better diagnostics ?
|
*/
|
|
static void gsm_error(struct gsm_mux *gsm,
|
unsigned char data, unsigned char flag)
|
{
|
gsm->state = GSM_SEARCH;
|
gsm->io_error++;
|
}
|
|
/**
|
* gsm_cleanup_mux - generic GSM protocol cleanup
|
* @gsm: our mux
|
* @disc: disconnect link?
|
*
|
* Clean up the bits of the mux which are the same for all framing
|
* protocols. Remove the mux from the mux table, stop all the timers
|
* and then shut down each device hanging up the channels as we go.
|
*/
|
|
static void gsm_cleanup_mux(struct gsm_mux *gsm, bool disc)
|
{
|
int i;
|
struct gsm_dlci *dlci;
|
struct gsm_msg *txq, *ntxq;
|
|
gsm->dead = true;
|
mutex_lock(&gsm->mutex);
|
|
dlci = gsm->dlci[0];
|
if (dlci) {
|
if (disc && dlci->state != DLCI_CLOSED) {
|
gsm_dlci_begin_close(dlci);
|
wait_event(gsm->event, dlci->state == DLCI_CLOSED);
|
}
|
dlci->dead = true;
|
}
|
|
/* Finish outstanding timers, making sure they are done */
|
del_timer_sync(&gsm->t2_timer);
|
|
/* Free up any link layer users and finally the control channel */
|
for (i = NUM_DLCI - 1; i >= 0; i--)
|
if (gsm->dlci[i]) {
|
gsm_dlci_release(gsm->dlci[i]);
|
gsm->dlci[i] = NULL;
|
}
|
mutex_unlock(&gsm->mutex);
|
/* Now wipe the queues */
|
tty_ldisc_flush(gsm->tty);
|
list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)
|
kfree(txq);
|
INIT_LIST_HEAD(&gsm->tx_list);
|
}
|
|
/**
|
* gsm_activate_mux - generic GSM setup
|
* @gsm: our mux
|
*
|
* Set up the bits of the mux which are the same for all framing
|
* protocols. Add the mux to the mux table so it can be opened and
|
* finally kick off connecting to DLCI 0 on the modem.
|
*/
|
|
static int gsm_activate_mux(struct gsm_mux *gsm)
|
{
|
struct gsm_dlci *dlci;
|
|
if (gsm->encoding == 0)
|
gsm->receive = gsm0_receive;
|
else
|
gsm->receive = gsm1_receive;
|
|
dlci = gsm_dlci_alloc(gsm, 0);
|
if (dlci == NULL)
|
return -ENOMEM;
|
gsm->dead = false; /* Tty opens are now permissible */
|
return 0;
|
}
|
|
/**
|
* gsm_free_mux - free up a mux
|
* @gsm: mux to free
|
*
|
* Dispose of allocated resources for a dead mux
|
*/
|
static void gsm_free_mux(struct gsm_mux *gsm)
|
{
|
int i;
|
|
for (i = 0; i < MAX_MUX; i++) {
|
if (gsm == gsm_mux[i]) {
|
gsm_mux[i] = NULL;
|
break;
|
}
|
}
|
mutex_destroy(&gsm->mutex);
|
kfree(gsm->txframe);
|
kfree(gsm->buf);
|
kfree(gsm);
|
}
|
|
/**
|
* gsm_free_muxr - free up a mux
|
* @ref: kreference to the mux to free
|
*
|
* Dispose of allocated resources for a dead mux
|
*/
|
static void gsm_free_muxr(struct kref *ref)
|
{
|
struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
|
gsm_free_mux(gsm);
|
}
|
|
static inline void mux_get(struct gsm_mux *gsm)
|
{
|
unsigned long flags;
|
|
spin_lock_irqsave(&gsm_mux_lock, flags);
|
kref_get(&gsm->ref);
|
spin_unlock_irqrestore(&gsm_mux_lock, flags);
|
}
|
|
static inline void mux_put(struct gsm_mux *gsm)
|
{
|
unsigned long flags;
|
|
spin_lock_irqsave(&gsm_mux_lock, flags);
|
kref_put(&gsm->ref, gsm_free_muxr);
|
spin_unlock_irqrestore(&gsm_mux_lock, flags);
|
}
|
|
static inline unsigned int mux_num_to_base(struct gsm_mux *gsm)
|
{
|
return gsm->num * NUM_DLCI;
|
}
|
|
static inline unsigned int mux_line_to_num(unsigned int line)
|
{
|
return line / NUM_DLCI;
|
}
|
|
/**
|
* gsm_alloc_mux - allocate a mux
|
*
|
* Creates a new mux ready for activation.
|
*/
|
|
static struct gsm_mux *gsm_alloc_mux(void)
|
{
|
int i;
|
struct gsm_mux *gsm = kzalloc(sizeof(struct gsm_mux), GFP_KERNEL);
|
if (gsm == NULL)
|
return NULL;
|
gsm->buf = kmalloc(MAX_MRU + 1, GFP_KERNEL);
|
if (gsm->buf == NULL) {
|
kfree(gsm);
|
return NULL;
|
}
|
gsm->txframe = kmalloc(2 * (MAX_MTU + PROT_OVERHEAD - 1), GFP_KERNEL);
|
if (gsm->txframe == NULL) {
|
kfree(gsm->buf);
|
kfree(gsm);
|
return NULL;
|
}
|
spin_lock_init(&gsm->lock);
|
mutex_init(&gsm->mutex);
|
kref_init(&gsm->ref);
|
INIT_LIST_HEAD(&gsm->tx_list);
|
timer_setup(&gsm->t2_timer, gsm_control_retransmit, 0);
|
init_waitqueue_head(&gsm->event);
|
spin_lock_init(&gsm->control_lock);
|
spin_lock_init(&gsm->tx_lock);
|
|
gsm->t1 = T1;
|
gsm->t2 = T2;
|
gsm->n2 = N2;
|
gsm->ftype = UIH;
|
gsm->adaption = 1;
|
gsm->encoding = 1;
|
gsm->mru = 64; /* Default to encoding 1 so these should be 64 */
|
gsm->mtu = 64;
|
gsm->dead = true; /* Avoid early tty opens */
|
|
/* Store the instance to the mux array or abort if no space is
|
* available.
|
*/
|
spin_lock(&gsm_mux_lock);
|
for (i = 0; i < MAX_MUX; i++) {
|
if (!gsm_mux[i]) {
|
gsm_mux[i] = gsm;
|
gsm->num = i;
|
break;
|
}
|
}
|
spin_unlock(&gsm_mux_lock);
|
if (i == MAX_MUX) {
|
mutex_destroy(&gsm->mutex);
|
kfree(gsm->txframe);
|
kfree(gsm->buf);
|
kfree(gsm);
|
return NULL;
|
}
|
|
return gsm;
|
}
|
|
static void gsm_copy_config_values(struct gsm_mux *gsm,
|
struct gsm_config *c)
|
{
|
memset(c, 0, sizeof(*c));
|
c->adaption = gsm->adaption;
|
c->encapsulation = gsm->encoding;
|
c->initiator = gsm->initiator;
|
c->t1 = gsm->t1;
|
c->t2 = gsm->t2;
|
c->t3 = 0; /* Not supported */
|
c->n2 = gsm->n2;
|
if (gsm->ftype == UIH)
|
c->i = 1;
|
else
|
c->i = 2;
|
pr_debug("Ftype %d i %d\n", gsm->ftype, c->i);
|
c->mru = gsm->mru;
|
c->mtu = gsm->mtu;
|
c->k = 0;
|
}
|
|
static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c)
|
{
|
int ret = 0;
|
int need_close = 0;
|
int need_restart = 0;
|
|
/* Stuff we don't support yet - UI or I frame transport, windowing */
|
if ((c->adaption != 1 && c->adaption != 2) || c->k)
|
return -EOPNOTSUPP;
|
/* Check the MRU/MTU range looks sane */
|
if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8)
|
return -EINVAL;
|
if (c->n2 > 255)
|
return -EINVAL;
|
if (c->encapsulation > 1) /* Basic, advanced, no I */
|
return -EINVAL;
|
if (c->initiator > 1)
|
return -EINVAL;
|
if (c->i == 0 || c->i > 2) /* UIH and UI only */
|
return -EINVAL;
|
/*
|
* See what is needed for reconfiguration
|
*/
|
|
/* Timing fields */
|
if (c->t1 != 0 && c->t1 != gsm->t1)
|
need_restart = 1;
|
if (c->t2 != 0 && c->t2 != gsm->t2)
|
need_restart = 1;
|
if (c->encapsulation != gsm->encoding)
|
need_restart = 1;
|
if (c->adaption != gsm->adaption)
|
need_restart = 1;
|
/* Requires care */
|
if (c->initiator != gsm->initiator)
|
need_close = 1;
|
if (c->mru != gsm->mru)
|
need_restart = 1;
|
if (c->mtu != gsm->mtu)
|
need_restart = 1;
|
|
/*
|
* Close down what is needed, restart and initiate the new
|
* configuration. On the first time there is no DLCI[0]
|
* and closing or cleaning up is not necessary.
|
*/
|
if (need_close || need_restart)
|
gsm_cleanup_mux(gsm, true);
|
|
gsm->initiator = c->initiator;
|
gsm->mru = c->mru;
|
gsm->mtu = c->mtu;
|
gsm->encoding = c->encapsulation;
|
gsm->adaption = c->adaption;
|
gsm->n2 = c->n2;
|
|
if (c->i == 1)
|
gsm->ftype = UIH;
|
else if (c->i == 2)
|
gsm->ftype = UI;
|
|
if (c->t1)
|
gsm->t1 = c->t1;
|
if (c->t2)
|
gsm->t2 = c->t2;
|
|
/*
|
* FIXME: We need to separate activation/deactivation from adding
|
* and removing from the mux array
|
*/
|
if (gsm->dead) {
|
ret = gsm_activate_mux(gsm);
|
if (ret)
|
return ret;
|
if (gsm->initiator)
|
gsm_dlci_begin_open(gsm->dlci[0]);
|
}
|
return 0;
|
}
|
|
/**
|
* gsmld_output - write to link
|
* @gsm: our mux
|
* @data: bytes to output
|
* @len: size
|
*
|
* Write a block of data from the GSM mux to the data channel. This
|
* will eventually be serialized from above but at the moment isn't.
|
*/
|
|
static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
|
{
|
if (tty_write_room(gsm->tty) < len) {
|
set_bit(TTY_DO_WRITE_WAKEUP, &gsm->tty->flags);
|
return -ENOSPC;
|
}
|
if (debug & 4)
|
print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
|
data, len);
|
gsm->tty->ops->write(gsm->tty, data, len);
|
return len;
|
}
|
|
/**
|
* gsmld_attach_gsm - mode set up
|
* @tty: our tty structure
|
* @gsm: our mux
|
*
|
* Set up the MUX for basic mode and commence connecting to the
|
* modem. Currently called from the line discipline set up but
|
* will need moving to an ioctl path.
|
*/
|
|
static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
|
{
|
unsigned int base;
|
int ret, i;
|
|
gsm->tty = tty_kref_get(tty);
|
/* Turn off tty XON/XOFF handling to handle it explicitly. */
|
gsm->old_c_iflag = tty->termios.c_iflag;
|
tty->termios.c_iflag &= (IXON | IXOFF);
|
ret = gsm_activate_mux(gsm);
|
if (ret != 0)
|
tty_kref_put(gsm->tty);
|
else {
|
/* Don't register device 0 - this is the control channel and not
|
a usable tty interface */
|
base = mux_num_to_base(gsm); /* Base for this MUX */
|
for (i = 1; i < NUM_DLCI; i++) {
|
struct device *dev;
|
|
dev = tty_register_device(gsm_tty_driver,
|
base + i, NULL);
|
if (IS_ERR(dev)) {
|
for (i--; i >= 1; i--)
|
tty_unregister_device(gsm_tty_driver,
|
base + i);
|
return PTR_ERR(dev);
|
}
|
}
|
}
|
return ret;
|
}
|
|
|
/**
|
* gsmld_detach_gsm - stop doing 0710 mux
|
* @tty: tty attached to the mux
|
* @gsm: mux
|
*
|
* Shutdown and then clean up the resources used by the line discipline
|
*/
|
|
static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
|
{
|
unsigned int base = mux_num_to_base(gsm); /* Base for this MUX */
|
int i;
|
|
WARN_ON(tty != gsm->tty);
|
for (i = 1; i < NUM_DLCI; i++)
|
tty_unregister_device(gsm_tty_driver, base + i);
|
/* Restore tty XON/XOFF handling. */
|
gsm->tty->termios.c_iflag = gsm->old_c_iflag;
|
tty_kref_put(gsm->tty);
|
gsm->tty = NULL;
|
}
|
|
static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
|
char *fp, int count)
|
{
|
struct gsm_mux *gsm = tty->disc_data;
|
const unsigned char *dp;
|
char *f;
|
int i;
|
char flags = TTY_NORMAL;
|
|
if (debug & 4)
|
print_hex_dump_bytes("gsmld_receive: ", DUMP_PREFIX_OFFSET,
|
cp, count);
|
|
for (i = count, dp = cp, f = fp; i; i--, dp++) {
|
if (f)
|
flags = *f++;
|
switch (flags) {
|
case TTY_NORMAL:
|
gsm->receive(gsm, *dp);
|
break;
|
case TTY_OVERRUN:
|
case TTY_BREAK:
|
case TTY_PARITY:
|
case TTY_FRAME:
|
gsm_error(gsm, *dp, flags);
|
break;
|
default:
|
WARN_ONCE(1, "%s: unknown flag %d\n",
|
tty_name(tty), flags);
|
break;
|
}
|
}
|
/* FASYNC if needed ? */
|
/* If clogged call tty_throttle(tty); */
|
}
|
|
/**
|
* gsmld_flush_buffer - clean input queue
|
* @tty: terminal device
|
*
|
* Flush the input buffer. Called when the line discipline is
|
* being closed, when the tty layer wants the buffer flushed (eg
|
* at hangup).
|
*/
|
|
static void gsmld_flush_buffer(struct tty_struct *tty)
|
{
|
}
|
|
/**
|
* gsmld_close - close the ldisc for this tty
|
* @tty: device
|
*
|
* Called from the terminal layer when this line discipline is
|
* being shut down, either because of a close or becsuse of a
|
* discipline change. The function will not be called while other
|
* ldisc methods are in progress.
|
*/
|
|
static void gsmld_close(struct tty_struct *tty)
|
{
|
struct gsm_mux *gsm = tty->disc_data;
|
|
/* The ldisc locks and closes the port before calling our close. This
|
* means we have no way to do a proper disconnect. We will not bother
|
* to do one.
|
*/
|
gsm_cleanup_mux(gsm, false);
|
|
gsmld_detach_gsm(tty, gsm);
|
|
gsmld_flush_buffer(tty);
|
/* Do other clean up here */
|
mux_put(gsm);
|
}
|
|
/**
|
* gsmld_open - open an ldisc
|
* @tty: terminal to open
|
*
|
* Called when this line discipline is being attached to the
|
* terminal device. Can sleep. Called serialized so that no
|
* other events will occur in parallel. No further open will occur
|
* until a close.
|
*/
|
|
static int gsmld_open(struct tty_struct *tty)
|
{
|
struct gsm_mux *gsm;
|
int ret;
|
|
if (tty->ops->write == NULL)
|
return -EINVAL;
|
|
/* Attach our ldisc data */
|
gsm = gsm_alloc_mux();
|
if (gsm == NULL)
|
return -ENOMEM;
|
|
tty->disc_data = gsm;
|
tty->receive_room = 65536;
|
|
/* Attach the initial passive connection */
|
gsm->encoding = 1;
|
|
ret = gsmld_attach_gsm(tty, gsm);
|
if (ret != 0) {
|
gsm_cleanup_mux(gsm, false);
|
mux_put(gsm);
|
}
|
return ret;
|
}
|
|
/**
|
* gsmld_write_wakeup - asynchronous I/O notifier
|
* @tty: tty device
|
*
|
* Required for the ptys, serial driver etc. since processes
|
* that attach themselves to the master and rely on ASYNC
|
* IO must be woken up
|
*/
|
|
static void gsmld_write_wakeup(struct tty_struct *tty)
|
{
|
struct gsm_mux *gsm = tty->disc_data;
|
unsigned long flags;
|
|
/* Queue poll */
|
clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
|
spin_lock_irqsave(&gsm->tx_lock, flags);
|
gsm_data_kick(gsm, NULL);
|
if (gsm->tx_bytes < TX_THRESH_LO) {
|
gsm_dlci_data_sweep(gsm);
|
}
|
spin_unlock_irqrestore(&gsm->tx_lock, flags);
|
}
|
|
/**
|
* gsmld_read - read function for tty
|
* @tty: tty device
|
* @file: file object
|
* @buf: userspace buffer pointer
|
* @nr: size of I/O
|
*
|
* Perform reads for the line discipline. We are guaranteed that the
|
* line discipline will not be closed under us but we may get multiple
|
* parallel readers and must handle this ourselves. We may also get
|
* a hangup. Always called in user context, may sleep.
|
*
|
* This code must be sure never to sleep through a hangup.
|
*/
|
|
static ssize_t gsmld_read(struct tty_struct *tty, struct file *file,
|
unsigned char *buf, size_t nr,
|
void **cookie, unsigned long offset)
|
{
|
return -EOPNOTSUPP;
|
}
|
|
/**
|
* gsmld_write - write function for tty
|
* @tty: tty device
|
* @file: file object
|
* @buf: userspace buffer pointer
|
* @nr: size of I/O
|
*
|
* Called when the owner of the device wants to send a frame
|
* itself (or some other control data). The data is transferred
|
* as-is and must be properly framed and checksummed as appropriate
|
* by userspace. Frames are either sent whole or not at all as this
|
* avoids pain user side.
|
*/
|
|
static ssize_t gsmld_write(struct tty_struct *tty, struct file *file,
|
const unsigned char *buf, size_t nr)
|
{
|
struct gsm_mux *gsm = tty->disc_data;
|
unsigned long flags;
|
int space;
|
int ret;
|
|
if (!gsm)
|
return -ENODEV;
|
|
ret = -ENOBUFS;
|
spin_lock_irqsave(&gsm->tx_lock, flags);
|
space = tty_write_room(tty);
|
if (space >= nr)
|
ret = tty->ops->write(tty, buf, nr);
|
else
|
set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
|
spin_unlock_irqrestore(&gsm->tx_lock, flags);
|
|
return ret;
|
}
|
|
/**
|
* gsmld_poll - poll method for N_GSM0710
|
* @tty: terminal device
|
* @file: file accessing it
|
* @wait: poll table
|
*
|
* Called when the line discipline is asked to poll() for data or
|
* for special events. This code is not serialized with respect to
|
* other events save open/close.
|
*
|
* This code must be sure never to sleep through a hangup.
|
* Called without the kernel lock held - fine
|
*/
|
|
static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file,
|
poll_table *wait)
|
{
|
__poll_t mask = 0;
|
struct gsm_mux *gsm = tty->disc_data;
|
|
poll_wait(file, &tty->read_wait, wait);
|
poll_wait(file, &tty->write_wait, wait);
|
|
if (gsm->dead)
|
mask |= EPOLLHUP;
|
if (tty_hung_up_p(file))
|
mask |= EPOLLHUP;
|
if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
|
mask |= EPOLLHUP;
|
if (!tty_is_writelocked(tty) && tty_write_room(tty) > 0)
|
mask |= EPOLLOUT | EPOLLWRNORM;
|
return mask;
|
}
|
|
static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
|
unsigned int cmd, unsigned long arg)
|
{
|
struct gsm_config c;
|
struct gsm_mux *gsm = tty->disc_data;
|
unsigned int base;
|
|
switch (cmd) {
|
case GSMIOC_GETCONF:
|
gsm_copy_config_values(gsm, &c);
|
if (copy_to_user((void __user *)arg, &c, sizeof(c)))
|
return -EFAULT;
|
return 0;
|
case GSMIOC_SETCONF:
|
if (copy_from_user(&c, (void __user *)arg, sizeof(c)))
|
return -EFAULT;
|
return gsm_config(gsm, &c);
|
case GSMIOC_GETFIRST:
|
base = mux_num_to_base(gsm);
|
return put_user(base + 1, (__u32 __user *)arg);
|
default:
|
return n_tty_ioctl_helper(tty, file, cmd, arg);
|
}
|
}
|
|
/*
|
* Network interface
|
*
|
*/
|
|
static int gsm_mux_net_open(struct net_device *net)
|
{
|
pr_debug("%s called\n", __func__);
|
netif_start_queue(net);
|
return 0;
|
}
|
|
static int gsm_mux_net_close(struct net_device *net)
|
{
|
netif_stop_queue(net);
|
return 0;
|
}
|
|
static void dlci_net_free(struct gsm_dlci *dlci)
|
{
|
if (!dlci->net) {
|
WARN_ON(1);
|
return;
|
}
|
dlci->adaption = dlci->prev_adaption;
|
dlci->data = dlci->prev_data;
|
free_netdev(dlci->net);
|
dlci->net = NULL;
|
}
|
static void net_free(struct kref *ref)
|
{
|
struct gsm_mux_net *mux_net;
|
struct gsm_dlci *dlci;
|
|
mux_net = container_of(ref, struct gsm_mux_net, ref);
|
dlci = mux_net->dlci;
|
|
if (dlci->net) {
|
unregister_netdev(dlci->net);
|
dlci_net_free(dlci);
|
}
|
}
|
|
static inline void muxnet_get(struct gsm_mux_net *mux_net)
|
{
|
kref_get(&mux_net->ref);
|
}
|
|
static inline void muxnet_put(struct gsm_mux_net *mux_net)
|
{
|
kref_put(&mux_net->ref, net_free);
|
}
|
|
static netdev_tx_t gsm_mux_net_start_xmit(struct sk_buff *skb,
|
struct net_device *net)
|
{
|
struct gsm_mux_net *mux_net = netdev_priv(net);
|
struct gsm_dlci *dlci = mux_net->dlci;
|
muxnet_get(mux_net);
|
|
skb_queue_head(&dlci->skb_list, skb);
|
net->stats.tx_packets++;
|
net->stats.tx_bytes += skb->len;
|
gsm_dlci_data_kick(dlci);
|
/* And tell the kernel when the last transmit started. */
|
netif_trans_update(net);
|
muxnet_put(mux_net);
|
return NETDEV_TX_OK;
|
}
|
|
/* called when a packet did not ack after watchdogtimeout */
|
static void gsm_mux_net_tx_timeout(struct net_device *net, unsigned int txqueue)
|
{
|
/* Tell syslog we are hosed. */
|
dev_dbg(&net->dev, "Tx timed out.\n");
|
|
/* Update statistics */
|
net->stats.tx_errors++;
|
}
|
|
static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
|
const unsigned char *in_buf, int size)
|
{
|
struct net_device *net = dlci->net;
|
struct sk_buff *skb;
|
struct gsm_mux_net *mux_net = netdev_priv(net);
|
muxnet_get(mux_net);
|
|
/* Allocate an sk_buff */
|
skb = dev_alloc_skb(size + NET_IP_ALIGN);
|
if (!skb) {
|
/* We got no receive buffer. */
|
net->stats.rx_dropped++;
|
muxnet_put(mux_net);
|
return;
|
}
|
skb_reserve(skb, NET_IP_ALIGN);
|
skb_put_data(skb, in_buf, size);
|
|
skb->dev = net;
|
skb->protocol = htons(ETH_P_IP);
|
|
/* Ship it off to the kernel */
|
netif_rx(skb);
|
|
/* update out statistics */
|
net->stats.rx_packets++;
|
net->stats.rx_bytes += size;
|
muxnet_put(mux_net);
|
return;
|
}
|
|
static void gsm_mux_net_init(struct net_device *net)
|
{
|
static const struct net_device_ops gsm_netdev_ops = {
|
.ndo_open = gsm_mux_net_open,
|
.ndo_stop = gsm_mux_net_close,
|
.ndo_start_xmit = gsm_mux_net_start_xmit,
|
.ndo_tx_timeout = gsm_mux_net_tx_timeout,
|
};
|
|
net->netdev_ops = &gsm_netdev_ops;
|
|
/* fill in the other fields */
|
net->watchdog_timeo = GSM_NET_TX_TIMEOUT;
|
net->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
|
net->type = ARPHRD_NONE;
|
net->tx_queue_len = 10;
|
}
|
|
|
/* caller holds the dlci mutex */
|
static void gsm_destroy_network(struct gsm_dlci *dlci)
|
{
|
struct gsm_mux_net *mux_net;
|
|
pr_debug("destroy network interface\n");
|
if (!dlci->net)
|
return;
|
mux_net = netdev_priv(dlci->net);
|
muxnet_put(mux_net);
|
}
|
|
|
/* caller holds the dlci mutex */
|
static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc)
|
{
|
char *netname;
|
int retval = 0;
|
struct net_device *net;
|
struct gsm_mux_net *mux_net;
|
|
if (!capable(CAP_NET_ADMIN))
|
return -EPERM;
|
|
/* Already in a non tty mode */
|
if (dlci->adaption > 2)
|
return -EBUSY;
|
|
if (nc->protocol != htons(ETH_P_IP))
|
return -EPROTONOSUPPORT;
|
|
if (nc->adaption != 3 && nc->adaption != 4)
|
return -EPROTONOSUPPORT;
|
|
pr_debug("create network interface\n");
|
|
netname = "gsm%d";
|
if (nc->if_name[0] != '\0')
|
netname = nc->if_name;
|
net = alloc_netdev(sizeof(struct gsm_mux_net), netname,
|
NET_NAME_UNKNOWN, gsm_mux_net_init);
|
if (!net) {
|
pr_err("alloc_netdev failed\n");
|
return -ENOMEM;
|
}
|
net->mtu = dlci->gsm->mtu;
|
net->min_mtu = 8;
|
net->max_mtu = dlci->gsm->mtu;
|
mux_net = netdev_priv(net);
|
mux_net->dlci = dlci;
|
kref_init(&mux_net->ref);
|
strncpy(nc->if_name, net->name, IFNAMSIZ); /* return net name */
|
|
/* reconfigure dlci for network */
|
dlci->prev_adaption = dlci->adaption;
|
dlci->prev_data = dlci->data;
|
dlci->adaption = nc->adaption;
|
dlci->data = gsm_mux_rx_netchar;
|
dlci->net = net;
|
|
pr_debug("register netdev\n");
|
retval = register_netdev(net);
|
if (retval) {
|
pr_err("network register fail %d\n", retval);
|
dlci_net_free(dlci);
|
return retval;
|
}
|
return net->ifindex; /* return network index */
|
}
|
|
/* Line discipline for real tty */
|
static struct tty_ldisc_ops tty_ldisc_packet = {
|
.owner = THIS_MODULE,
|
.magic = TTY_LDISC_MAGIC,
|
.name = "n_gsm",
|
.open = gsmld_open,
|
.close = gsmld_close,
|
.flush_buffer = gsmld_flush_buffer,
|
.read = gsmld_read,
|
.write = gsmld_write,
|
.ioctl = gsmld_ioctl,
|
.poll = gsmld_poll,
|
.receive_buf = gsmld_receive_buf,
|
.write_wakeup = gsmld_write_wakeup
|
};
|
|
/*
|
* Virtual tty side
|
*/
|
|
#define TX_SIZE 512
|
|
static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk)
|
{
|
u8 modembits[3];
|
struct gsm_control *ctrl;
|
int len = 2;
|
|
modembits[0] = (dlci->addr << 2) | 2 | EA; /* DLCI, Valid, EA */
|
modembits[1] = (gsm_encode_modem(dlci) << 1) | EA;
|
if (brk) {
|
modembits[2] = (brk << 4) | 2 | EA; /* Length, Break, EA */
|
len++;
|
}
|
ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len);
|
if (ctrl == NULL)
|
return -ENOMEM;
|
return gsm_control_wait(dlci->gsm, ctrl);
|
}
|
|
static int gsm_carrier_raised(struct tty_port *port)
|
{
|
struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
|
struct gsm_mux *gsm = dlci->gsm;
|
|
/* Not yet open so no carrier info */
|
if (dlci->state != DLCI_OPEN)
|
return 0;
|
if (debug & 2)
|
return 1;
|
|
/*
|
* Basic mode with control channel in ADM mode may not respond
|
* to CMD_MSC at all and modem_rx is empty.
|
*/
|
if (gsm->encoding == 0 && gsm->dlci[0]->mode == DLCI_MODE_ADM &&
|
!dlci->modem_rx)
|
return 1;
|
|
return dlci->modem_rx & TIOCM_CD;
|
}
|
|
static void gsm_dtr_rts(struct tty_port *port, int onoff)
|
{
|
struct gsm_dlci *dlci = container_of(port, struct gsm_dlci, port);
|
unsigned int modem_tx = dlci->modem_tx;
|
if (onoff)
|
modem_tx |= TIOCM_DTR | TIOCM_RTS;
|
else
|
modem_tx &= ~(TIOCM_DTR | TIOCM_RTS);
|
if (modem_tx != dlci->modem_tx) {
|
dlci->modem_tx = modem_tx;
|
gsmtty_modem_update(dlci, 0);
|
}
|
}
|
|
static const struct tty_port_operations gsm_port_ops = {
|
.carrier_raised = gsm_carrier_raised,
|
.dtr_rts = gsm_dtr_rts,
|
.destruct = gsm_dlci_free,
|
};
|
|
static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
|
{
|
struct gsm_mux *gsm;
|
struct gsm_dlci *dlci;
|
unsigned int line = tty->index;
|
unsigned int mux = mux_line_to_num(line);
|
bool alloc = false;
|
int ret;
|
|
line = line & 0x3F;
|
|
if (mux >= MAX_MUX)
|
return -ENXIO;
|
/* FIXME: we need to lock gsm_mux for lifetimes of ttys eventually */
|
if (gsm_mux[mux] == NULL)
|
return -EUNATCH;
|
if (line == 0 || line > 61) /* 62/63 reserved */
|
return -ECHRNG;
|
gsm = gsm_mux[mux];
|
if (gsm->dead)
|
return -EL2HLT;
|
/* If DLCI 0 is not yet fully open return an error.
|
This is ok from a locking
|
perspective as we don't have to worry about this
|
if DLCI0 is lost */
|
mutex_lock(&gsm->mutex);
|
if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
|
mutex_unlock(&gsm->mutex);
|
return -EL2NSYNC;
|
}
|
dlci = gsm->dlci[line];
|
if (dlci == NULL) {
|
alloc = true;
|
dlci = gsm_dlci_alloc(gsm, line);
|
}
|
if (dlci == NULL) {
|
mutex_unlock(&gsm->mutex);
|
return -ENOMEM;
|
}
|
ret = tty_port_install(&dlci->port, driver, tty);
|
if (ret) {
|
if (alloc)
|
dlci_put(dlci);
|
mutex_unlock(&gsm->mutex);
|
return ret;
|
}
|
|
dlci_get(dlci);
|
dlci_get(gsm->dlci[0]);
|
mux_get(gsm);
|
tty->driver_data = dlci;
|
mutex_unlock(&gsm->mutex);
|
|
return 0;
|
}
|
|
static int gsmtty_open(struct tty_struct *tty, struct file *filp)
|
{
|
struct gsm_dlci *dlci = tty->driver_data;
|
struct tty_port *port = &dlci->port;
|
struct gsm_mux *gsm = dlci->gsm;
|
|
port->count++;
|
tty_port_tty_set(port, tty);
|
|
dlci->modem_rx = 0;
|
/* We could in theory open and close before we wait - eg if we get
|
a DM straight back. This is ok as that will have caused a hangup */
|
tty_port_set_initialized(port, 1);
|
/* Start sending off SABM messages */
|
if (gsm->initiator)
|
gsm_dlci_begin_open(dlci);
|
else
|
gsm_dlci_set_opening(dlci);
|
/* And wait for virtual carrier */
|
return tty_port_block_til_ready(port, tty, filp);
|
}
|
|
static void gsmtty_close(struct tty_struct *tty, struct file *filp)
|
{
|
struct gsm_dlci *dlci = tty->driver_data;
|
|
if (dlci == NULL)
|
return;
|
if (dlci->state == DLCI_CLOSED)
|
return;
|
mutex_lock(&dlci->mutex);
|
gsm_destroy_network(dlci);
|
mutex_unlock(&dlci->mutex);
|
if (tty_port_close_start(&dlci->port, tty, filp) == 0)
|
return;
|
gsm_dlci_begin_close(dlci);
|
if (tty_port_initialized(&dlci->port) && C_HUPCL(tty))
|
tty_port_lower_dtr_rts(&dlci->port);
|
tty_port_close_end(&dlci->port, tty);
|
tty_port_tty_set(&dlci->port, NULL);
|
return;
|
}
|
|
static void gsmtty_hangup(struct tty_struct *tty)
|
{
|
struct gsm_dlci *dlci = tty->driver_data;
|
if (dlci->state == DLCI_CLOSED)
|
return;
|
tty_port_hangup(&dlci->port);
|
gsm_dlci_begin_close(dlci);
|
}
|
|
static int gsmtty_write(struct tty_struct *tty, const unsigned char *buf,
|
int len)
|
{
|
int sent;
|
struct gsm_dlci *dlci = tty->driver_data;
|
if (dlci->state == DLCI_CLOSED)
|
return -EINVAL;
|
/* Stuff the bytes into the fifo queue */
|
sent = kfifo_in_locked(&dlci->fifo, buf, len, &dlci->lock);
|
/* Need to kick the channel */
|
gsm_dlci_data_kick(dlci);
|
return sent;
|
}
|
|
static int gsmtty_write_room(struct tty_struct *tty)
|
{
|
struct gsm_dlci *dlci = tty->driver_data;
|
if (dlci->state == DLCI_CLOSED)
|
return -EINVAL;
|
return TX_SIZE - kfifo_len(&dlci->fifo);
|
}
|
|
static int gsmtty_chars_in_buffer(struct tty_struct *tty)
|
{
|
struct gsm_dlci *dlci = tty->driver_data;
|
if (dlci->state == DLCI_CLOSED)
|
return -EINVAL;
|
return kfifo_len(&dlci->fifo);
|
}
|
|
static void gsmtty_flush_buffer(struct tty_struct *tty)
|
{
|
struct gsm_dlci *dlci = tty->driver_data;
|
unsigned long flags;
|
|
if (dlci->state == DLCI_CLOSED)
|
return;
|
/* Caution needed: If we implement reliable transport classes
|
then the data being transmitted can't simply be junked once
|
it has first hit the stack. Until then we can just blow it
|
away */
|
spin_lock_irqsave(&dlci->lock, flags);
|
kfifo_reset(&dlci->fifo);
|
spin_unlock_irqrestore(&dlci->lock, flags);
|
/* Need to unhook this DLCI from the transmit queue logic */
|
}
|
|
static void gsmtty_wait_until_sent(struct tty_struct *tty, int timeout)
|
{
|
/* The FIFO handles the queue so the kernel will do the right
|
thing waiting on chars_in_buffer before calling us. No work
|
to do here */
|
}
|
|
static int gsmtty_tiocmget(struct tty_struct *tty)
|
{
|
struct gsm_dlci *dlci = tty->driver_data;
|
if (dlci->state == DLCI_CLOSED)
|
return -EINVAL;
|
return dlci->modem_rx;
|
}
|
|
static int gsmtty_tiocmset(struct tty_struct *tty,
|
unsigned int set, unsigned int clear)
|
{
|
struct gsm_dlci *dlci = tty->driver_data;
|
unsigned int modem_tx = dlci->modem_tx;
|
|
if (dlci->state == DLCI_CLOSED)
|
return -EINVAL;
|
modem_tx &= ~clear;
|
modem_tx |= set;
|
|
if (modem_tx != dlci->modem_tx) {
|
dlci->modem_tx = modem_tx;
|
return gsmtty_modem_update(dlci, 0);
|
}
|
return 0;
|
}
|
|
|
static int gsmtty_ioctl(struct tty_struct *tty,
|
unsigned int cmd, unsigned long arg)
|
{
|
struct gsm_dlci *dlci = tty->driver_data;
|
struct gsm_netconfig nc;
|
int index;
|
|
if (dlci->state == DLCI_CLOSED)
|
return -EINVAL;
|
switch (cmd) {
|
case GSMIOC_ENABLE_NET:
|
if (copy_from_user(&nc, (void __user *)arg, sizeof(nc)))
|
return -EFAULT;
|
nc.if_name[IFNAMSIZ-1] = '\0';
|
/* return net interface index or error code */
|
mutex_lock(&dlci->mutex);
|
index = gsm_create_network(dlci, &nc);
|
mutex_unlock(&dlci->mutex);
|
if (copy_to_user((void __user *)arg, &nc, sizeof(nc)))
|
return -EFAULT;
|
return index;
|
case GSMIOC_DISABLE_NET:
|
if (!capable(CAP_NET_ADMIN))
|
return -EPERM;
|
mutex_lock(&dlci->mutex);
|
gsm_destroy_network(dlci);
|
mutex_unlock(&dlci->mutex);
|
return 0;
|
default:
|
return -ENOIOCTLCMD;
|
}
|
}
|
|
static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
|
{
|
struct gsm_dlci *dlci = tty->driver_data;
|
if (dlci->state == DLCI_CLOSED)
|
return;
|
/* For the moment its fixed. In actual fact the speed information
|
for the virtual channel can be propogated in both directions by
|
the RPN control message. This however rapidly gets nasty as we
|
then have to remap modem signals each way according to whether
|
our virtual cable is null modem etc .. */
|
tty_termios_copy_hw(&tty->termios, old);
|
}
|
|
static void gsmtty_throttle(struct tty_struct *tty)
|
{
|
struct gsm_dlci *dlci = tty->driver_data;
|
if (dlci->state == DLCI_CLOSED)
|
return;
|
if (C_CRTSCTS(tty))
|
dlci->modem_tx &= ~TIOCM_RTS;
|
dlci->throttled = true;
|
/* Send an MSC with RTS cleared */
|
gsmtty_modem_update(dlci, 0);
|
}
|
|
static void gsmtty_unthrottle(struct tty_struct *tty)
|
{
|
struct gsm_dlci *dlci = tty->driver_data;
|
if (dlci->state == DLCI_CLOSED)
|
return;
|
if (C_CRTSCTS(tty))
|
dlci->modem_tx |= TIOCM_RTS;
|
dlci->throttled = false;
|
/* Send an MSC with RTS set */
|
gsmtty_modem_update(dlci, 0);
|
}
|
|
static int gsmtty_break_ctl(struct tty_struct *tty, int state)
|
{
|
struct gsm_dlci *dlci = tty->driver_data;
|
int encode = 0; /* Off */
|
if (dlci->state == DLCI_CLOSED)
|
return -EINVAL;
|
|
if (state == -1) /* "On indefinitely" - we can't encode this
|
properly */
|
encode = 0x0F;
|
else if (state > 0) {
|
encode = state / 200; /* mS to encoding */
|
if (encode > 0x0F)
|
encode = 0x0F; /* Best effort */
|
}
|
return gsmtty_modem_update(dlci, encode);
|
}
|
|
static void gsmtty_cleanup(struct tty_struct *tty)
|
{
|
struct gsm_dlci *dlci = tty->driver_data;
|
struct gsm_mux *gsm = dlci->gsm;
|
|
dlci_put(dlci);
|
dlci_put(gsm->dlci[0]);
|
mux_put(gsm);
|
}
|
|
/* Virtual ttys for the demux */
|
static const struct tty_operations gsmtty_ops = {
|
.install = gsmtty_install,
|
.open = gsmtty_open,
|
.close = gsmtty_close,
|
.write = gsmtty_write,
|
.write_room = gsmtty_write_room,
|
.chars_in_buffer = gsmtty_chars_in_buffer,
|
.flush_buffer = gsmtty_flush_buffer,
|
.ioctl = gsmtty_ioctl,
|
.throttle = gsmtty_throttle,
|
.unthrottle = gsmtty_unthrottle,
|
.set_termios = gsmtty_set_termios,
|
.hangup = gsmtty_hangup,
|
.wait_until_sent = gsmtty_wait_until_sent,
|
.tiocmget = gsmtty_tiocmget,
|
.tiocmset = gsmtty_tiocmset,
|
.break_ctl = gsmtty_break_ctl,
|
.cleanup = gsmtty_cleanup,
|
};
|
|
|
|
static int __init gsm_init(void)
|
{
|
/* Fill in our line protocol discipline, and register it */
|
int status = tty_register_ldisc(N_GSM0710, &tty_ldisc_packet);
|
if (status != 0) {
|
pr_err("n_gsm: can't register line discipline (err = %d)\n",
|
status);
|
return status;
|
}
|
|
gsm_tty_driver = alloc_tty_driver(256);
|
if (!gsm_tty_driver) {
|
tty_unregister_ldisc(N_GSM0710);
|
pr_err("gsm_init: tty allocation failed.\n");
|
return -EINVAL;
|
}
|
gsm_tty_driver->driver_name = "gsmtty";
|
gsm_tty_driver->name = "gsmtty";
|
gsm_tty_driver->major = 0; /* Dynamic */
|
gsm_tty_driver->minor_start = 0;
|
gsm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
|
gsm_tty_driver->subtype = SERIAL_TYPE_NORMAL;
|
gsm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV
|
| TTY_DRIVER_HARDWARE_BREAK;
|
gsm_tty_driver->init_termios = tty_std_termios;
|
/* Fixme */
|
gsm_tty_driver->init_termios.c_lflag &= ~ECHO;
|
tty_set_operations(gsm_tty_driver, &gsmtty_ops);
|
|
spin_lock_init(&gsm_mux_lock);
|
|
if (tty_register_driver(gsm_tty_driver)) {
|
put_tty_driver(gsm_tty_driver);
|
tty_unregister_ldisc(N_GSM0710);
|
pr_err("gsm_init: tty registration failed.\n");
|
return -EBUSY;
|
}
|
pr_debug("gsm_init: loaded as %d,%d.\n",
|
gsm_tty_driver->major, gsm_tty_driver->minor_start);
|
return 0;
|
}
|
|
static void __exit gsm_exit(void)
|
{
|
int status = tty_unregister_ldisc(N_GSM0710);
|
if (status != 0)
|
pr_err("n_gsm: can't unregister line discipline (err = %d)\n",
|
status);
|
tty_unregister_driver(gsm_tty_driver);
|
put_tty_driver(gsm_tty_driver);
|
}
|
|
module_init(gsm_init);
|
module_exit(gsm_exit);
|
|
|
MODULE_LICENSE("GPL");
|
MODULE_ALIAS_LDISC(N_GSM0710);
|
