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 */
6
7 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
8
9 #include <linux/string.h>
10 #include <linux/skbuff.h>
11 #include <linux/hardirq.h>
12 #include <linux/export.h>
13 #include <net/caif/cfpkt.h>
14
15 #define PKT_PREFIX 48
16 #define PKT_POSTFIX 2
17 #define PKT_LEN_WHEN_EXTENDING 128
18 #define PKT_ERROR(pkt, errmsg) \
19 do { \
20 cfpkt_priv(pkt)->erronous = true; \
21 skb_reset_tail_pointer(&pkt->skb); \
22 pr_warn(errmsg); \
23 } while (0)
24
25 struct cfpktq {
26 struct sk_buff_head head;
27 atomic_t count;
28 /* Lock protects count updates */
29 spinlock_t lock;
30 };
31
32 /*
33 * net/caif/ is generic and does not
34 * understand SKB, so we do this typecast
35 */
36 struct cfpkt {
37 struct sk_buff skb;
38 };
39
40 /* Private data inside SKB */
41 struct cfpkt_priv_data {
42 struct dev_info dev_info;
43 bool erronous;
44 };
45
cfpkt_priv(struct cfpkt * pkt)46 static inline struct cfpkt_priv_data *cfpkt_priv(struct cfpkt *pkt)
47 {
48 return (struct cfpkt_priv_data *) pkt->skb.cb;
49 }
50
is_erronous(struct cfpkt * pkt)51 static inline bool is_erronous(struct cfpkt *pkt)
52 {
53 return cfpkt_priv(pkt)->erronous;
54 }
55
pkt_to_skb(struct cfpkt * pkt)56 static inline struct sk_buff *pkt_to_skb(struct cfpkt *pkt)
57 {
58 return &pkt->skb;
59 }
60
skb_to_pkt(struct sk_buff * skb)61 static inline struct cfpkt *skb_to_pkt(struct sk_buff *skb)
62 {
63 return (struct cfpkt *) skb;
64 }
65
cfpkt_fromnative(enum caif_direction dir,void * nativepkt)66 struct cfpkt *cfpkt_fromnative(enum caif_direction dir, void *nativepkt)
67 {
68 struct cfpkt *pkt = skb_to_pkt(nativepkt);
69 cfpkt_priv(pkt)->erronous = false;
70 return pkt;
71 }
72 EXPORT_SYMBOL(cfpkt_fromnative);
73
cfpkt_tonative(struct cfpkt * pkt)74 void *cfpkt_tonative(struct cfpkt *pkt)
75 {
76 return (void *) pkt;
77 }
78 EXPORT_SYMBOL(cfpkt_tonative);
79
cfpkt_create_pfx(u16 len,u16 pfx)80 static struct cfpkt *cfpkt_create_pfx(u16 len, u16 pfx)
81 {
82 struct sk_buff *skb;
83
84 if (likely(in_interrupt()))
85 skb = alloc_skb(len + pfx, GFP_ATOMIC);
86 else
87 skb = alloc_skb(len + pfx, GFP_KERNEL);
88
89 if (unlikely(skb == NULL))
90 return NULL;
91
92 skb_reserve(skb, pfx);
93 return skb_to_pkt(skb);
94 }
95
cfpkt_create(u16 len)96 inline struct cfpkt *cfpkt_create(u16 len)
97 {
98 return cfpkt_create_pfx(len + PKT_POSTFIX, PKT_PREFIX);
99 }
100
cfpkt_destroy(struct cfpkt * pkt)101 void cfpkt_destroy(struct cfpkt *pkt)
102 {
103 struct sk_buff *skb = pkt_to_skb(pkt);
104 kfree_skb(skb);
105 }
106
cfpkt_more(struct cfpkt * pkt)107 inline bool cfpkt_more(struct cfpkt *pkt)
108 {
109 struct sk_buff *skb = pkt_to_skb(pkt);
110 return skb->len > 0;
111 }
112
cfpkt_peek_head(struct cfpkt * pkt,void * data,u16 len)113 int cfpkt_peek_head(struct cfpkt *pkt, void *data, u16 len)
114 {
115 struct sk_buff *skb = pkt_to_skb(pkt);
116 if (skb_headlen(skb) >= len) {
117 memcpy(data, skb->data, len);
118 return 0;
119 }
120 return !cfpkt_extr_head(pkt, data, len) &&
121 !cfpkt_add_head(pkt, data, len);
122 }
123
cfpkt_extr_head(struct cfpkt * pkt,void * data,u16 len)124 int cfpkt_extr_head(struct cfpkt *pkt, void *data, u16 len)
125 {
126 struct sk_buff *skb = pkt_to_skb(pkt);
127 u8 *from;
128 if (unlikely(is_erronous(pkt)))
129 return -EPROTO;
130
131 if (unlikely(len > skb->len)) {
132 PKT_ERROR(pkt, "read beyond end of packet\n");
133 return -EPROTO;
134 }
135
136 if (unlikely(len > skb_headlen(skb))) {
137 if (unlikely(skb_linearize(skb) != 0)) {
138 PKT_ERROR(pkt, "linearize failed\n");
139 return -EPROTO;
140 }
141 }
142 from = skb_pull(skb, len);
143 from -= len;
144 if (data)
145 memcpy(data, from, len);
146 return 0;
147 }
148 EXPORT_SYMBOL(cfpkt_extr_head);
149
cfpkt_extr_trail(struct cfpkt * pkt,void * dta,u16 len)150 int cfpkt_extr_trail(struct cfpkt *pkt, void *dta, u16 len)
151 {
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;
157
158 if (unlikely(skb_linearize(skb) != 0)) {
159 PKT_ERROR(pkt, "linearize failed\n");
160 return -EPROTO;
161 }
162 if (unlikely(skb->data + len > skb_tail_pointer(skb))) {
163 PKT_ERROR(pkt, "read beyond end of packet\n");
164 return -EPROTO;
165 }
166 from = skb_tail_pointer(skb) - len;
167 skb_trim(skb, skb->len - len);
168 memcpy(data, from, len);
169 return 0;
170 }
171
cfpkt_pad_trail(struct cfpkt * pkt,u16 len)172 int cfpkt_pad_trail(struct cfpkt *pkt, u16 len)
173 {
174 return cfpkt_add_body(pkt, NULL, len);
175 }
176
cfpkt_add_body(struct cfpkt * pkt,const void * data,u16 len)177 int cfpkt_add_body(struct cfpkt *pkt, const void *data, u16 len)
178 {
179 struct sk_buff *skb = pkt_to_skb(pkt);
180 struct sk_buff *lastskb;
181 u8 *to;
182 u16 addlen = 0;
183
184
185 if (unlikely(is_erronous(pkt)))
186 return -EPROTO;
187
188 lastskb = skb;
189
190 /* Check whether we need to add space at the tail */
191 if (unlikely(skb_tailroom(skb) < len)) {
192 if (likely(len < PKT_LEN_WHEN_EXTENDING))
193 addlen = PKT_LEN_WHEN_EXTENDING;
194 else
195 addlen = len;
196 }
197
198 /* Check whether we need to change the SKB before writing to the tail */
199 if (unlikely((addlen > 0) || skb_cloned(skb) || skb_shared(skb))) {
200
201 /* Make sure data is writable */
202 if (unlikely(skb_cow_data(skb, addlen, &lastskb) < 0)) {
203 PKT_ERROR(pkt, "cow failed\n");
204 return -EPROTO;
205 }
206 /*
207 * Is the SKB non-linear after skb_cow_data()? If so, we are
208 * going to add data to the last SKB, so we need to adjust
209 * lengths of the top SKB.
210 */
211 if (lastskb != skb) {
212 pr_warn("Packet is non-linear\n");
213 skb->len += len;
214 skb->data_len += len;
215 }
216 }
217
218 /* All set to put the last SKB and optionally write data there. */
219 to = skb_put(lastskb, len);
220 if (likely(data))
221 memcpy(to, data, len);
222 return 0;
223 }
224
cfpkt_addbdy(struct cfpkt * pkt,u8 data)225 inline int cfpkt_addbdy(struct cfpkt *pkt, u8 data)
226 {
227 return cfpkt_add_body(pkt, &data, 1);
228 }
229
cfpkt_add_head(struct cfpkt * pkt,const void * data2,u16 len)230 int cfpkt_add_head(struct cfpkt *pkt, const void *data2, u16 len)
231 {
232 struct sk_buff *skb = pkt_to_skb(pkt);
233 struct sk_buff *lastskb;
234 u8 *to;
235 const u8 *data = data2;
236 int ret;
237 if (unlikely(is_erronous(pkt)))
238 return -EPROTO;
239 if (unlikely(skb_headroom(skb) < len)) {
240 PKT_ERROR(pkt, "no headroom\n");
241 return -EPROTO;
242 }
243
244 /* Make sure data is writable */
245 ret = skb_cow_data(skb, 0, &lastskb);
246 if (unlikely(ret < 0)) {
247 PKT_ERROR(pkt, "cow failed\n");
248 return ret;
249 }
250
251 to = skb_push(skb, len);
252 memcpy(to, data, len);
253 return 0;
254 }
255 EXPORT_SYMBOL(cfpkt_add_head);
256
cfpkt_add_trail(struct cfpkt * pkt,const void * data,u16 len)257 inline int cfpkt_add_trail(struct cfpkt *pkt, const void *data, u16 len)
258 {
259 return cfpkt_add_body(pkt, data, len);
260 }
261
cfpkt_getlen(struct cfpkt * pkt)262 inline u16 cfpkt_getlen(struct cfpkt *pkt)
263 {
264 struct sk_buff *skb = pkt_to_skb(pkt);
265 return skb->len;
266 }
267
cfpkt_iterate(struct cfpkt * pkt,u16 (* iter_func)(u16,void *,u16),u16 data)268 inline u16 cfpkt_iterate(struct cfpkt *pkt,
269 u16 (*iter_func)(u16, void *, u16),
270 u16 data)
271 {
272 /*
273 * Don't care about the performance hit of linearizing,
274 * Checksum should not be used on high-speed interfaces anyway.
275 */
276 if (unlikely(is_erronous(pkt)))
277 return -EPROTO;
278 if (unlikely(skb_linearize(&pkt->skb) != 0)) {
279 PKT_ERROR(pkt, "linearize failed\n");
280 return -EPROTO;
281 }
282 return iter_func(data, pkt->skb.data, cfpkt_getlen(pkt));
283 }
284
cfpkt_setlen(struct cfpkt * pkt,u16 len)285 int cfpkt_setlen(struct cfpkt *pkt, u16 len)
286 {
287 struct sk_buff *skb = pkt_to_skb(pkt);
288
289
290 if (unlikely(is_erronous(pkt)))
291 return -EPROTO;
292
293 if (likely(len <= skb->len)) {
294 if (unlikely(skb->data_len))
295 ___pskb_trim(skb, len);
296 else
297 skb_trim(skb, len);
298
299 return cfpkt_getlen(pkt);
300 }
301
302 /* Need to expand SKB */
303 if (unlikely(!cfpkt_pad_trail(pkt, len - skb->len)))
304 PKT_ERROR(pkt, "skb_pad_trail failed\n");
305
306 return cfpkt_getlen(pkt);
307 }
308
cfpkt_append(struct cfpkt * dstpkt,struct cfpkt * addpkt,u16 expectlen)309 struct cfpkt *cfpkt_append(struct cfpkt *dstpkt,
310 struct cfpkt *addpkt,
311 u16 expectlen)
312 {
313 struct sk_buff *dst = pkt_to_skb(dstpkt);
314 struct sk_buff *add = pkt_to_skb(addpkt);
315 u16 addlen = skb_headlen(add);
316 u16 neededtailspace;
317 struct sk_buff *tmp;
318 u16 dstlen;
319 u16 createlen;
320 if (unlikely(is_erronous(dstpkt) || is_erronous(addpkt))) {
321 return dstpkt;
322 }
323 if (expectlen > addlen)
324 neededtailspace = expectlen;
325 else
326 neededtailspace = addlen;
327
328 if (dst->tail + neededtailspace > dst->end) {
329 /* Create a dumplicate of 'dst' with more tail space */
330 struct cfpkt *tmppkt;
331 dstlen = skb_headlen(dst);
332 createlen = dstlen + neededtailspace;
333 tmppkt = cfpkt_create(createlen + PKT_PREFIX + PKT_POSTFIX);
334 if (tmppkt == NULL)
335 return NULL;
336 tmp = pkt_to_skb(tmppkt);
337 skb_set_tail_pointer(tmp, dstlen);
338 tmp->len = dstlen;
339 memcpy(tmp->data, dst->data, dstlen);
340 cfpkt_destroy(dstpkt);
341 dst = tmp;
342 }
343 memcpy(skb_tail_pointer(dst), add->data, skb_headlen(add));
344 cfpkt_destroy(addpkt);
345 dst->tail += addlen;
346 dst->len += addlen;
347 return skb_to_pkt(dst);
348 }
349
cfpkt_split(struct cfpkt * pkt,u16 pos)350 struct cfpkt *cfpkt_split(struct cfpkt *pkt, u16 pos)
351 {
352 struct sk_buff *skb2;
353 struct sk_buff *skb = pkt_to_skb(pkt);
354 struct cfpkt *tmppkt;
355 u8 *split = skb->data + pos;
356 u16 len2nd = skb_tail_pointer(skb) - split;
357
358 if (unlikely(is_erronous(pkt)))
359 return NULL;
360
361 if (skb->data + pos > skb_tail_pointer(skb)) {
362 PKT_ERROR(pkt, "trying to split beyond end of packet\n");
363 return NULL;
364 }
365
366 /* Create a new packet for the second part of the data */
367 tmppkt = cfpkt_create_pfx(len2nd + PKT_PREFIX + PKT_POSTFIX,
368 PKT_PREFIX);
369 if (tmppkt == NULL)
370 return NULL;
371 skb2 = pkt_to_skb(tmppkt);
372
373
374 if (skb2 == NULL)
375 return NULL;
376
377 /* Reduce the length of the original packet */
378 skb_set_tail_pointer(skb, pos);
379 skb->len = pos;
380
381 memcpy(skb2->data, split, len2nd);
382 skb2->tail += len2nd;
383 skb2->len += len2nd;
384 return skb_to_pkt(skb2);
385 }
386
cfpkt_erroneous(struct cfpkt * pkt)387 bool cfpkt_erroneous(struct cfpkt *pkt)
388 {
389 return cfpkt_priv(pkt)->erronous;
390 }
391
cfpkt_info(struct cfpkt * pkt)392 struct caif_payload_info *cfpkt_info(struct cfpkt *pkt)
393 {
394 return (struct caif_payload_info *)&pkt_to_skb(pkt)->cb;
395 }
396 EXPORT_SYMBOL(cfpkt_info);
397