Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[linux-btrfs-devel.git] / net / caif / cfpkt_skbuff.c
blob75d4bfae1a78714b46dc303769ff26f2b6bc8b91
1 /*
2 * Copyright (C) ST-Ericsson AB 2010
3 * Author: Sjur Brendeland/sjur.brandeland@stericsson.com
4 * License terms: GNU General Public License (GPL) version 2
5 */
7 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
9 #include <linux/string.h>
10 #include <linux/skbuff.h>
11 #include <linux/hardirq.h>
12 #include <net/caif/cfpkt.h>
14 #define PKT_PREFIX 48
15 #define PKT_POSTFIX 2
16 #define PKT_LEN_WHEN_EXTENDING 128
17 #define PKT_ERROR(pkt, errmsg) \
18 do { \
19 cfpkt_priv(pkt)->erronous = true; \
20 skb_reset_tail_pointer(&pkt->skb); \
21 pr_warn(errmsg); \
22 } while (0)
24 struct cfpktq {
25 struct sk_buff_head head;
26 atomic_t count;
27 /* Lock protects count updates */
28 spinlock_t lock;
32 * net/caif/ is generic and does not
33 * understand SKB, so we do this typecast
35 struct cfpkt {
36 struct sk_buff skb;
39 /* Private data inside SKB */
40 struct cfpkt_priv_data {
41 struct dev_info dev_info;
42 bool erronous;
45 static inline struct cfpkt_priv_data *cfpkt_priv(struct cfpkt *pkt)
47 return (struct cfpkt_priv_data *) pkt->skb.cb;
50 static inline bool is_erronous(struct cfpkt *pkt)
52 return cfpkt_priv(pkt)->erronous;
55 static inline struct sk_buff *pkt_to_skb(struct cfpkt *pkt)
57 return &pkt->skb;
60 static inline struct cfpkt *skb_to_pkt(struct sk_buff *skb)
62 return (struct cfpkt *) skb;
66 struct cfpkt *cfpkt_fromnative(enum caif_direction dir, void *nativepkt)
68 struct cfpkt *pkt = skb_to_pkt(nativepkt);
69 cfpkt_priv(pkt)->erronous = false;
70 return pkt;
72 EXPORT_SYMBOL(cfpkt_fromnative);
74 void *cfpkt_tonative(struct cfpkt *pkt)
76 return (void *) pkt;
78 EXPORT_SYMBOL(cfpkt_tonative);
80 static struct cfpkt *cfpkt_create_pfx(u16 len, u16 pfx)
82 struct sk_buff *skb;
84 if (likely(in_interrupt()))
85 skb = alloc_skb(len + pfx, GFP_ATOMIC);
86 else
87 skb = alloc_skb(len + pfx, GFP_KERNEL);
89 if (unlikely(skb == NULL))
90 return NULL;
92 skb_reserve(skb, pfx);
93 return skb_to_pkt(skb);
96 inline struct cfpkt *cfpkt_create(u16 len)
98 return cfpkt_create_pfx(len + PKT_POSTFIX, PKT_PREFIX);
101 void cfpkt_destroy(struct cfpkt *pkt)
103 struct sk_buff *skb = pkt_to_skb(pkt);
104 kfree_skb(skb);
108 inline bool cfpkt_more(struct cfpkt *pkt)
110 struct sk_buff *skb = pkt_to_skb(pkt);
111 return skb->len > 0;
115 int cfpkt_peek_head(struct cfpkt *pkt, void *data, u16 len)
117 struct sk_buff *skb = pkt_to_skb(pkt);
118 if (skb_headlen(skb) >= len) {
119 memcpy(data, skb->data, len);
120 return 0;
122 return !cfpkt_extr_head(pkt, data, len) &&
123 !cfpkt_add_head(pkt, data, len);
126 int cfpkt_extr_head(struct cfpkt *pkt, void *data, u16 len)
128 struct sk_buff *skb = pkt_to_skb(pkt);
129 u8 *from;
130 if (unlikely(is_erronous(pkt)))
131 return -EPROTO;
133 if (unlikely(len > skb->len)) {
134 PKT_ERROR(pkt, "read beyond end of packet\n");
135 return -EPROTO;
138 if (unlikely(len > skb_headlen(skb))) {
139 if (unlikely(skb_linearize(skb) != 0)) {
140 PKT_ERROR(pkt, "linearize failed\n");
141 return -EPROTO;
144 from = skb_pull(skb, len);
145 from -= len;
146 memcpy(data, from, len);
147 return 0;
150 int cfpkt_extr_trail(struct cfpkt *pkt, void *dta, u16 len)
152 struct sk_buff *skb = pkt_to_skb(pkt);
153 u8 *data = dta;
154 u8 *from;
155 if (unlikely(is_erronous(pkt)))
156 return -EPROTO;
158 if (unlikely(skb_linearize(skb) != 0)) {
159 PKT_ERROR(pkt, "linearize failed\n");
160 return -EPROTO;
162 if (unlikely(skb->data + len > skb_tail_pointer(skb))) {
163 PKT_ERROR(pkt, "read beyond end of packet\n");
164 return -EPROTO;
166 from = skb_tail_pointer(skb) - len;
167 skb_trim(skb, skb->len - len);
168 memcpy(data, from, len);
169 return 0;
173 int cfpkt_pad_trail(struct cfpkt *pkt, u16 len)
175 return cfpkt_add_body(pkt, NULL, len);
179 int cfpkt_add_body(struct cfpkt *pkt, const void *data, u16 len)
181 struct sk_buff *skb = pkt_to_skb(pkt);
182 struct sk_buff *lastskb;
183 u8 *to;
184 u16 addlen = 0;
187 if (unlikely(is_erronous(pkt)))
188 return -EPROTO;
190 lastskb = skb;
192 /* Check whether we need to add space at the tail */
193 if (unlikely(skb_tailroom(skb) < len)) {
194 if (likely(len < PKT_LEN_WHEN_EXTENDING))
195 addlen = PKT_LEN_WHEN_EXTENDING;
196 else
197 addlen = len;
200 /* Check whether we need to change the SKB before writing to the tail */
201 if (unlikely((addlen > 0) || skb_cloned(skb) || skb_shared(skb))) {
203 /* Make sure data is writable */
204 if (unlikely(skb_cow_data(skb, addlen, &lastskb) < 0)) {
205 PKT_ERROR(pkt, "cow failed\n");
206 return -EPROTO;
209 * Is the SKB non-linear after skb_cow_data()? If so, we are
210 * going to add data to the last SKB, so we need to adjust
211 * lengths of the top SKB.
213 if (lastskb != skb) {
214 pr_warn("Packet is non-linear\n");
215 skb->len += len;
216 skb->data_len += len;
220 /* All set to put the last SKB and optionally write data there. */
221 to = skb_put(lastskb, len);
222 if (likely(data))
223 memcpy(to, data, len);
224 return 0;
227 inline int cfpkt_addbdy(struct cfpkt *pkt, u8 data)
229 return cfpkt_add_body(pkt, &data, 1);
232 int cfpkt_add_head(struct cfpkt *pkt, const void *data2, u16 len)
234 struct sk_buff *skb = pkt_to_skb(pkt);
235 struct sk_buff *lastskb;
236 u8 *to;
237 const u8 *data = data2;
238 int ret;
239 if (unlikely(is_erronous(pkt)))
240 return -EPROTO;
241 if (unlikely(skb_headroom(skb) < len)) {
242 PKT_ERROR(pkt, "no headroom\n");
243 return -EPROTO;
246 /* Make sure data is writable */
247 ret = skb_cow_data(skb, 0, &lastskb);
248 if (unlikely(ret < 0)) {
249 PKT_ERROR(pkt, "cow failed\n");
250 return ret;
253 to = skb_push(skb, len);
254 memcpy(to, data, len);
255 return 0;
259 inline int cfpkt_add_trail(struct cfpkt *pkt, const void *data, u16 len)
261 return cfpkt_add_body(pkt, data, len);
265 inline u16 cfpkt_getlen(struct cfpkt *pkt)
267 struct sk_buff *skb = pkt_to_skb(pkt);
268 return skb->len;
272 inline u16 cfpkt_iterate(struct cfpkt *pkt,
273 u16 (*iter_func)(u16, void *, u16),
274 u16 data)
277 * Don't care about the performance hit of linearizing,
278 * Checksum should not be used on high-speed interfaces anyway.
280 if (unlikely(is_erronous(pkt)))
281 return -EPROTO;
282 if (unlikely(skb_linearize(&pkt->skb) != 0)) {
283 PKT_ERROR(pkt, "linearize failed\n");
284 return -EPROTO;
286 return iter_func(data, pkt->skb.data, cfpkt_getlen(pkt));
290 int cfpkt_setlen(struct cfpkt *pkt, u16 len)
292 struct sk_buff *skb = pkt_to_skb(pkt);
295 if (unlikely(is_erronous(pkt)))
296 return -EPROTO;
298 if (likely(len <= skb->len)) {
299 if (unlikely(skb->data_len))
300 ___pskb_trim(skb, len);
301 else
302 skb_trim(skb, len);
304 return cfpkt_getlen(pkt);
307 /* Need to expand SKB */
308 if (unlikely(!cfpkt_pad_trail(pkt, len - skb->len)))
309 PKT_ERROR(pkt, "skb_pad_trail failed\n");
311 return cfpkt_getlen(pkt);
314 struct cfpkt *cfpkt_append(struct cfpkt *dstpkt,
315 struct cfpkt *addpkt,
316 u16 expectlen)
318 struct sk_buff *dst = pkt_to_skb(dstpkt);
319 struct sk_buff *add = pkt_to_skb(addpkt);
320 u16 addlen = skb_headlen(add);
321 u16 neededtailspace;
322 struct sk_buff *tmp;
323 u16 dstlen;
324 u16 createlen;
325 if (unlikely(is_erronous(dstpkt) || is_erronous(addpkt))) {
326 return dstpkt;
328 if (expectlen > addlen)
329 neededtailspace = expectlen;
330 else
331 neededtailspace = addlen;
333 if (dst->tail + neededtailspace > dst->end) {
334 /* Create a dumplicate of 'dst' with more tail space */
335 struct cfpkt *tmppkt;
336 dstlen = skb_headlen(dst);
337 createlen = dstlen + neededtailspace;
338 tmppkt = cfpkt_create(createlen + PKT_PREFIX + PKT_POSTFIX);
339 if (tmppkt == NULL)
340 return NULL;
341 tmp = pkt_to_skb(tmppkt);
342 skb_set_tail_pointer(tmp, dstlen);
343 tmp->len = dstlen;
344 memcpy(tmp->data, dst->data, dstlen);
345 cfpkt_destroy(dstpkt);
346 dst = tmp;
348 memcpy(skb_tail_pointer(dst), add->data, skb_headlen(add));
349 cfpkt_destroy(addpkt);
350 dst->tail += addlen;
351 dst->len += addlen;
352 return skb_to_pkt(dst);
355 struct cfpkt *cfpkt_split(struct cfpkt *pkt, u16 pos)
357 struct sk_buff *skb2;
358 struct sk_buff *skb = pkt_to_skb(pkt);
359 struct cfpkt *tmppkt;
360 u8 *split = skb->data + pos;
361 u16 len2nd = skb_tail_pointer(skb) - split;
363 if (unlikely(is_erronous(pkt)))
364 return NULL;
366 if (skb->data + pos > skb_tail_pointer(skb)) {
367 PKT_ERROR(pkt, "trying to split beyond end of packet\n");
368 return NULL;
371 /* Create a new packet for the second part of the data */
372 tmppkt = cfpkt_create_pfx(len2nd + PKT_PREFIX + PKT_POSTFIX,
373 PKT_PREFIX);
374 if (tmppkt == NULL)
375 return NULL;
376 skb2 = pkt_to_skb(tmppkt);
379 if (skb2 == NULL)
380 return NULL;
382 /* Reduce the length of the original packet */
383 skb_set_tail_pointer(skb, pos);
384 skb->len = pos;
386 memcpy(skb2->data, split, len2nd);
387 skb2->tail += len2nd;
388 skb2->len += len2nd;
389 return skb_to_pkt(skb2);
392 bool cfpkt_erroneous(struct cfpkt *pkt)
394 return cfpkt_priv(pkt)->erronous;
397 struct caif_payload_info *cfpkt_info(struct cfpkt *pkt)
399 return (struct caif_payload_info *)&pkt_to_skb(pkt)->cb;