/*
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* Copyright (C) ST-Ericsson AB 2010
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* Author: Sjur Brendeland
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* License terms: GNU General Public License (GPL) version 2
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
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#include <linux/string.h>
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#include <linux/skbuff.h>
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#include <linux/export.h>
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#include <net/caif/cfpkt.h>
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#define PKT_PREFIX 48
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#define PKT_POSTFIX 2
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#define PKT_LEN_WHEN_EXTENDING 128
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#define PKT_ERROR(pkt, errmsg) \
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do { \
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cfpkt_priv(pkt)->erronous = true; \
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skb_reset_tail_pointer(&pkt->skb); \
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pr_warn(errmsg); \
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} while (0)
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struct cfpktq {
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struct sk_buff_head head;
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atomic_t count;
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/* Lock protects count updates */
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spinlock_t lock;
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};
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/*
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* net/caif/ is generic and does not
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* understand SKB, so we do this typecast
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*/
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struct cfpkt {
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struct sk_buff skb;
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};
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/* Private data inside SKB */
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struct cfpkt_priv_data {
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struct dev_info dev_info;
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bool erronous;
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};
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static inline struct cfpkt_priv_data *cfpkt_priv(struct cfpkt *pkt)
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{
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return (struct cfpkt_priv_data *) pkt->skb.cb;
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}
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static inline bool is_erronous(struct cfpkt *pkt)
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{
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return cfpkt_priv(pkt)->erronous;
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}
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static inline struct sk_buff *pkt_to_skb(struct cfpkt *pkt)
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{
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return &pkt->skb;
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}
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static inline struct cfpkt *skb_to_pkt(struct sk_buff *skb)
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{
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return (struct cfpkt *) skb;
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}
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struct cfpkt *cfpkt_fromnative(enum caif_direction dir, void *nativepkt)
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{
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struct cfpkt *pkt = skb_to_pkt(nativepkt);
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cfpkt_priv(pkt)->erronous = false;
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return pkt;
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}
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EXPORT_SYMBOL(cfpkt_fromnative);
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void *cfpkt_tonative(struct cfpkt *pkt)
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{
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return (void *) pkt;
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}
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EXPORT_SYMBOL(cfpkt_tonative);
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static struct cfpkt *cfpkt_create_pfx(u16 len, u16 pfx)
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{
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struct sk_buff *skb;
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skb = alloc_skb(len + pfx, GFP_ATOMIC);
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if (unlikely(skb == NULL))
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return NULL;
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skb_reserve(skb, pfx);
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return skb_to_pkt(skb);
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}
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inline struct cfpkt *cfpkt_create(u16 len)
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{
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return cfpkt_create_pfx(len + PKT_POSTFIX, PKT_PREFIX);
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}
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void cfpkt_destroy(struct cfpkt *pkt)
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{
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struct sk_buff *skb = pkt_to_skb(pkt);
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kfree_skb(skb);
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}
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inline bool cfpkt_more(struct cfpkt *pkt)
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{
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struct sk_buff *skb = pkt_to_skb(pkt);
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return skb->len > 0;
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}
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int cfpkt_peek_head(struct cfpkt *pkt, void *data, u16 len)
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{
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struct sk_buff *skb = pkt_to_skb(pkt);
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if (skb_headlen(skb) >= len) {
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memcpy(data, skb->data, len);
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return 0;
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}
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return !cfpkt_extr_head(pkt, data, len) &&
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!cfpkt_add_head(pkt, data, len);
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}
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int cfpkt_extr_head(struct cfpkt *pkt, void *data, u16 len)
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{
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struct sk_buff *skb = pkt_to_skb(pkt);
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u8 *from;
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if (unlikely(is_erronous(pkt)))
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return -EPROTO;
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if (unlikely(len > skb->len)) {
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PKT_ERROR(pkt, "read beyond end of packet\n");
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return -EPROTO;
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}
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if (unlikely(len > skb_headlen(skb))) {
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if (unlikely(skb_linearize(skb) != 0)) {
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PKT_ERROR(pkt, "linearize failed\n");
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return -EPROTO;
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}
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}
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from = skb_pull(skb, len);
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from -= len;
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if (data)
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memcpy(data, from, len);
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return 0;
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}
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EXPORT_SYMBOL(cfpkt_extr_head);
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int cfpkt_extr_trail(struct cfpkt *pkt, void *dta, u16 len)
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{
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struct sk_buff *skb = pkt_to_skb(pkt);
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u8 *data = dta;
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u8 *from;
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if (unlikely(is_erronous(pkt)))
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return -EPROTO;
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if (unlikely(skb_linearize(skb) != 0)) {
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PKT_ERROR(pkt, "linearize failed\n");
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return -EPROTO;
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}
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if (unlikely(skb->data + len > skb_tail_pointer(skb))) {
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PKT_ERROR(pkt, "read beyond end of packet\n");
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return -EPROTO;
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}
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from = skb_tail_pointer(skb) - len;
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skb_trim(skb, skb->len - len);
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memcpy(data, from, len);
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return 0;
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}
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int cfpkt_pad_trail(struct cfpkt *pkt, u16 len)
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{
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return cfpkt_add_body(pkt, NULL, len);
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}
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int cfpkt_add_body(struct cfpkt *pkt, const void *data, u16 len)
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{
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struct sk_buff *skb = pkt_to_skb(pkt);
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struct sk_buff *lastskb;
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u8 *to;
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u16 addlen = 0;
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if (unlikely(is_erronous(pkt)))
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return -EPROTO;
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lastskb = skb;
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/* Check whether we need to add space at the tail */
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if (unlikely(skb_tailroom(skb) < len)) {
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if (likely(len < PKT_LEN_WHEN_EXTENDING))
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addlen = PKT_LEN_WHEN_EXTENDING;
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else
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addlen = len;
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}
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/* Check whether we need to change the SKB before writing to the tail */
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if (unlikely((addlen > 0) || skb_cloned(skb) || skb_shared(skb))) {
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/* Make sure data is writable */
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if (unlikely(skb_cow_data(skb, addlen, &lastskb) < 0)) {
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PKT_ERROR(pkt, "cow failed\n");
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return -EPROTO;
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}
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}
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/* All set to put the last SKB and optionally write data there. */
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to = pskb_put(skb, lastskb, len);
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if (likely(data))
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memcpy(to, data, len);
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return 0;
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}
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inline int cfpkt_addbdy(struct cfpkt *pkt, u8 data)
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{
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return cfpkt_add_body(pkt, &data, 1);
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}
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int cfpkt_add_head(struct cfpkt *pkt, const void *data2, u16 len)
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{
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struct sk_buff *skb = pkt_to_skb(pkt);
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struct sk_buff *lastskb;
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u8 *to;
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const u8 *data = data2;
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int ret;
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if (unlikely(is_erronous(pkt)))
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return -EPROTO;
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if (unlikely(skb_headroom(skb) < len)) {
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PKT_ERROR(pkt, "no headroom\n");
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return -EPROTO;
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}
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/* Make sure data is writable */
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ret = skb_cow_data(skb, 0, &lastskb);
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if (unlikely(ret < 0)) {
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PKT_ERROR(pkt, "cow failed\n");
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return ret;
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}
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to = skb_push(skb, len);
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memcpy(to, data, len);
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return 0;
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}
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EXPORT_SYMBOL(cfpkt_add_head);
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inline int cfpkt_add_trail(struct cfpkt *pkt, const void *data, u16 len)
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{
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return cfpkt_add_body(pkt, data, len);
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}
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inline u16 cfpkt_getlen(struct cfpkt *pkt)
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{
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struct sk_buff *skb = pkt_to_skb(pkt);
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return skb->len;
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}
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int cfpkt_iterate(struct cfpkt *pkt,
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u16 (*iter_func)(u16, void *, u16),
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u16 data)
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{
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/*
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* Don't care about the performance hit of linearizing,
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* Checksum should not be used on high-speed interfaces anyway.
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*/
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if (unlikely(is_erronous(pkt)))
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return -EPROTO;
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if (unlikely(skb_linearize(&pkt->skb) != 0)) {
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PKT_ERROR(pkt, "linearize failed\n");
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return -EPROTO;
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}
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return iter_func(data, pkt->skb.data, cfpkt_getlen(pkt));
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}
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int cfpkt_setlen(struct cfpkt *pkt, u16 len)
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{
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struct sk_buff *skb = pkt_to_skb(pkt);
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if (unlikely(is_erronous(pkt)))
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return -EPROTO;
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if (likely(len <= skb->len)) {
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if (unlikely(skb->data_len))
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___pskb_trim(skb, len);
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else
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skb_trim(skb, len);
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return cfpkt_getlen(pkt);
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}
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/* Need to expand SKB */
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if (unlikely(!cfpkt_pad_trail(pkt, len - skb->len)))
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PKT_ERROR(pkt, "skb_pad_trail failed\n");
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return cfpkt_getlen(pkt);
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}
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struct cfpkt *cfpkt_append(struct cfpkt *dstpkt,
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struct cfpkt *addpkt,
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u16 expectlen)
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{
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struct sk_buff *dst = pkt_to_skb(dstpkt);
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struct sk_buff *add = pkt_to_skb(addpkt);
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u16 addlen = skb_headlen(add);
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u16 neededtailspace;
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struct sk_buff *tmp;
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u16 dstlen;
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u16 createlen;
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if (unlikely(is_erronous(dstpkt) || is_erronous(addpkt))) {
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return dstpkt;
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}
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if (expectlen > addlen)
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neededtailspace = expectlen;
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else
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neededtailspace = addlen;
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if (dst->tail + neededtailspace > dst->end) {
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/* Create a dumplicate of 'dst' with more tail space */
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struct cfpkt *tmppkt;
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dstlen = skb_headlen(dst);
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createlen = dstlen + neededtailspace;
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tmppkt = cfpkt_create(createlen + PKT_PREFIX + PKT_POSTFIX);
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if (tmppkt == NULL)
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return NULL;
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tmp = pkt_to_skb(tmppkt);
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skb_set_tail_pointer(tmp, dstlen);
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tmp->len = dstlen;
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memcpy(tmp->data, dst->data, dstlen);
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cfpkt_destroy(dstpkt);
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dst = tmp;
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}
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memcpy(skb_tail_pointer(dst), add->data, skb_headlen(add));
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cfpkt_destroy(addpkt);
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dst->tail += addlen;
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dst->len += addlen;
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return skb_to_pkt(dst);
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}
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struct cfpkt *cfpkt_split(struct cfpkt *pkt, u16 pos)
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{
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struct sk_buff *skb2;
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struct sk_buff *skb = pkt_to_skb(pkt);
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struct cfpkt *tmppkt;
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u8 *split = skb->data + pos;
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u16 len2nd = skb_tail_pointer(skb) - split;
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if (unlikely(is_erronous(pkt)))
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return NULL;
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if (skb->data + pos > skb_tail_pointer(skb)) {
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PKT_ERROR(pkt, "trying to split beyond end of packet\n");
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return NULL;
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}
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/* Create a new packet for the second part of the data */
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tmppkt = cfpkt_create_pfx(len2nd + PKT_PREFIX + PKT_POSTFIX,
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PKT_PREFIX);
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if (tmppkt == NULL)
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return NULL;
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skb2 = pkt_to_skb(tmppkt);
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if (skb2 == NULL)
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return NULL;
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/* Reduce the length of the original packet */
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skb_set_tail_pointer(skb, pos);
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skb->len = pos;
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memcpy(skb2->data, split, len2nd);
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skb2->tail += len2nd;
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skb2->len += len2nd;
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skb2->priority = skb->priority;
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return skb_to_pkt(skb2);
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}
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bool cfpkt_erroneous(struct cfpkt *pkt)
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{
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return cfpkt_priv(pkt)->erronous;
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}
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struct caif_payload_info *cfpkt_info(struct cfpkt *pkt)
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{
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return (struct caif_payload_info *)&pkt_to_skb(pkt)->cb;
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}
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EXPORT_SYMBOL(cfpkt_info);
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void cfpkt_set_prio(struct cfpkt *pkt, int prio)
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{
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pkt_to_skb(pkt)->priority = prio;
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}
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EXPORT_SYMBOL(cfpkt_set_prio);
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