From 1543e317f1da31b75942316931e8f491a8920811 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Thu, 04 Jan 2024 10:08:02 +0000
Subject: [PATCH] disable FB

---
 kernel/drivers/net/wan/hdlc_x25.c |  165 ++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 files changed, 151 insertions(+), 14 deletions(-)

diff --git a/kernel/drivers/net/wan/hdlc_x25.c b/kernel/drivers/net/wan/hdlc_x25.c
index e867638..6938cb3 100644
--- a/kernel/drivers/net/wan/hdlc_x25.c
+++ b/kernel/drivers/net/wan/hdlc_x25.c
@@ -1,12 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Generic HDLC support routines for Linux
  * X.25 support
  *
  * Copyright (C) 1999 - 2006 Krzysztof Halasa <khc@pm.waw.pl>
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of version 2 of the GNU General Public License
- * as published by the Free Software Foundation.
  */
 
 #include <linux/errno.h>
@@ -24,7 +21,18 @@
 #include <linux/skbuff.h>
 #include <net/x25device.h>
 
+struct x25_state {
+	x25_hdlc_proto settings;
+	bool up;
+	spinlock_t up_lock; /* Protects "up" */
+};
+
 static int x25_ioctl(struct net_device *dev, struct ifreq *ifr);
+
+static struct x25_state *state(hdlc_device *hdlc)
+{
+	return hdlc->state;
+}
 
 /* These functions are callbacks called by LAPB layer */
 
@@ -65,10 +73,13 @@
 {
 	unsigned char *ptr;
 
-	skb_push(skb, 1);
-
-	if (skb_cow(skb, 1))
+	if (skb_cow(skb, 1)) {
+		kfree_skb(skb);
 		return NET_RX_DROP;
+	}
+
+	skb_push(skb, 1);
+	skb_reset_network_header(skb);
 
 	ptr  = skb->data;
 	*ptr = X25_IFACE_DATA;
@@ -82,6 +93,13 @@
 static void x25_data_transmit(struct net_device *dev, struct sk_buff *skb)
 {
 	hdlc_device *hdlc = dev_to_hdlc(dev);
+
+	skb_reset_network_header(skb);
+	skb->protocol = hdlc_type_trans(skb, dev);
+
+	if (dev_nit_active(dev))
+		dev_queue_xmit_nit(skb, dev);
+
 	hdlc->xmit(skb, dev); /* Ignore return value :-( */
 }
 
@@ -89,15 +107,32 @@
 
 static netdev_tx_t x25_xmit(struct sk_buff *skb, struct net_device *dev)
 {
+	hdlc_device *hdlc = dev_to_hdlc(dev);
+	struct x25_state *x25st = state(hdlc);
 	int result;
 
+	/* There should be a pseudo header of 1 byte added by upper layers.
+	 * Check to make sure it is there before reading it.
+	 */
+	if (skb->len < 1) {
+		kfree_skb(skb);
+		return NETDEV_TX_OK;
+	}
 
-	/* X.25 to LAPB */
+	spin_lock_bh(&x25st->up_lock);
+	if (!x25st->up) {
+		spin_unlock_bh(&x25st->up_lock);
+		kfree_skb(skb);
+		return NETDEV_TX_OK;
+	}
+
 	switch (skb->data[0]) {
 	case X25_IFACE_DATA:	/* Data to be transmitted */
 		skb_pull(skb, 1);
+		skb_reset_network_header(skb);
 		if ((result = lapb_data_request(dev, skb)) != LAPB_OK)
 			dev_kfree_skb(skb);
+		spin_unlock_bh(&x25st->up_lock);
 		return NETDEV_TX_OK;
 
 	case X25_IFACE_CONNECT:
@@ -126,6 +161,7 @@
 		break;
 	}
 
+	spin_unlock_bh(&x25st->up_lock);
 	dev_kfree_skb(skb);
 	return NETDEV_TX_OK;
 }
@@ -134,7 +170,6 @@
 
 static int x25_open(struct net_device *dev)
 {
-	int result;
 	static const struct lapb_register_struct cb = {
 		.connect_confirmation = x25_connected,
 		.connect_indication = x25_connected,
@@ -143,10 +178,38 @@
 		.data_indication = x25_data_indication,
 		.data_transmit = x25_data_transmit,
 	};
+	hdlc_device *hdlc = dev_to_hdlc(dev);
+	struct x25_state *x25st = state(hdlc);
+	struct lapb_parms_struct params;
+	int result;
 
 	result = lapb_register(dev, &cb);
 	if (result != LAPB_OK)
-		return result;
+		return -ENOMEM;
+
+	result = lapb_getparms(dev, &params);
+	if (result != LAPB_OK)
+		return -EINVAL;
+
+	if (state(hdlc)->settings.dce)
+		params.mode = params.mode | LAPB_DCE;
+
+	if (state(hdlc)->settings.modulo == 128)
+		params.mode = params.mode | LAPB_EXTENDED;
+
+	params.window = state(hdlc)->settings.window;
+	params.t1 = state(hdlc)->settings.t1;
+	params.t2 = state(hdlc)->settings.t2;
+	params.n2 = state(hdlc)->settings.n2;
+
+	result = lapb_setparms(dev, &params);
+	if (result != LAPB_OK)
+		return -EINVAL;
+
+	spin_lock_bh(&x25st->up_lock);
+	x25st->up = true;
+	spin_unlock_bh(&x25st->up_lock);
+
 	return 0;
 }
 
@@ -154,6 +217,13 @@
 
 static void x25_close(struct net_device *dev)
 {
+	hdlc_device *hdlc = dev_to_hdlc(dev);
+	struct x25_state *x25st = state(hdlc);
+
+	spin_lock_bh(&x25st->up_lock);
+	x25st->up = false;
+	spin_unlock_bh(&x25st->up_lock);
+
 	lapb_unregister(dev);
 }
 
@@ -162,15 +232,28 @@
 static int x25_rx(struct sk_buff *skb)
 {
 	struct net_device *dev = skb->dev;
+	hdlc_device *hdlc = dev_to_hdlc(dev);
+	struct x25_state *x25st = state(hdlc);
 
 	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
 		dev->stats.rx_dropped++;
 		return NET_RX_DROP;
 	}
 
-	if (lapb_data_received(dev, skb) == LAPB_OK)
-		return NET_RX_SUCCESS;
+	spin_lock_bh(&x25st->up_lock);
+	if (!x25st->up) {
+		spin_unlock_bh(&x25st->up_lock);
+		kfree_skb(skb);
+		dev->stats.rx_dropped++;
+		return NET_RX_DROP;
+	}
 
+	if (lapb_data_received(dev, skb) == LAPB_OK) {
+		spin_unlock_bh(&x25st->up_lock);
+		return NET_RX_SUCCESS;
+	}
+
+	spin_unlock_bh(&x25st->up_lock);
 	dev->stats.rx_errors++;
 	dev_kfree_skb_any(skb);
 	return NET_RX_DROP;
@@ -189,7 +272,10 @@
 
 static int x25_ioctl(struct net_device *dev, struct ifreq *ifr)
 {
+	x25_hdlc_proto __user *x25_s = ifr->ifr_settings.ifs_ifsu.x25;
+	const size_t size = sizeof(x25_hdlc_proto);
 	hdlc_device *hdlc = dev_to_hdlc(dev);
+	x25_hdlc_proto new_settings;
 	int result;
 
 	switch (ifr->ifr_settings.type) {
@@ -197,7 +283,13 @@
 		if (dev_to_hdlc(dev)->proto != &proto)
 			return -EINVAL;
 		ifr->ifr_settings.type = IF_PROTO_X25;
-		return 0; /* return protocol only, no settable parameters */
+		if (ifr->ifr_settings.size < size) {
+			ifr->ifr_settings.size = size; /* data size wanted */
+			return -ENOBUFS;
+		}
+		if (copy_to_user(x25_s, &state(hdlc)->settings, size))
+			return -EFAULT;
+		return 0;
 
 	case IF_PROTO_X25:
 		if (!capable(CAP_NET_ADMIN))
@@ -206,12 +298,57 @@
 		if (dev->flags & IFF_UP)
 			return -EBUSY;
 
+		/* backward compatibility */
+		if (ifr->ifr_settings.size == 0) {
+			new_settings.dce = 0;
+			new_settings.modulo = 8;
+			new_settings.window = 7;
+			new_settings.t1 = 3;
+			new_settings.t2 = 1;
+			new_settings.n2 = 10;
+		}
+		else {
+			if (copy_from_user(&new_settings, x25_s, size))
+				return -EFAULT;
+
+			if ((new_settings.dce != 0 &&
+			new_settings.dce != 1) ||
+			(new_settings.modulo != 8 &&
+			new_settings.modulo != 128) ||
+			new_settings.window < 1 ||
+			(new_settings.modulo == 8 &&
+			new_settings.window > 7) ||
+			(new_settings.modulo == 128 &&
+			new_settings.window > 127) ||
+			new_settings.t1 < 1 ||
+			new_settings.t1 > 255 ||
+			new_settings.t2 < 1 ||
+			new_settings.t2 > 255 ||
+			new_settings.n2 < 1 ||
+			new_settings.n2 > 255)
+				return -EINVAL;
+		}
+
 		result=hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
 		if (result)
 			return result;
 
-		if ((result = attach_hdlc_protocol(dev, &proto, 0)))
+		if ((result = attach_hdlc_protocol(dev, &proto,
+						   sizeof(struct x25_state))))
 			return result;
+
+		memcpy(&state(hdlc)->settings, &new_settings, size);
+		state(hdlc)->up = false;
+		spin_lock_init(&state(hdlc)->up_lock);
+
+		/* There's no header_ops so hard_header_len should be 0. */
+		dev->hard_header_len = 0;
+		/* When transmitting data:
+		 * first we'll remove a pseudo header of 1 byte,
+		 * then we'll prepend an LAPB header of at most 3 bytes.
+		 */
+		dev->needed_headroom = 3 - 1;
+
 		dev->type = ARPHRD_X25;
 		call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
 		netif_dormant_off(dev);

--
Gitblit v1.6.2