1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) ST-Ericsson AB 2010
4 * Author: Sjur Brendeland
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/export.h>
12 #include <net/caif/cfpkt.h>
13
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)
23
24 struct cfpktq {
25 struct sk_buff_head head;
26 atomic_t count;
27 /* Lock protects count updates */
28 spinlock_t lock;
29 };
30
31 /*
32 * net/caif/ is generic and does not
33 * understand SKB, so we do this typecast
34 */
35 struct cfpkt {
36 struct sk_buff skb;
37 };
38
39 /* Private data inside SKB */
40 struct cfpkt_priv_data {
41 struct dev_info dev_info;
42 bool erronous;
43 };
44
cfpkt_priv(struct cfpkt * pkt)45 static inline struct cfpkt_priv_data *cfpkt_priv(struct cfpkt *pkt)
46 {
47 return (struct cfpkt_priv_data *) pkt->skb.cb;
48 }
49
is_erronous(struct cfpkt * pkt)50 static inline bool is_erronous(struct cfpkt *pkt)
51 {
52 return cfpkt_priv(pkt)->erronous;
53 }
54
pkt_to_skb(struct cfpkt * pkt)55 static inline struct sk_buff *pkt_to_skb(struct cfpkt *pkt)
56 {
57 return &pkt->skb;
58 }
59
skb_to_pkt(struct sk_buff * skb)60 static inline struct cfpkt *skb_to_pkt(struct sk_buff *skb)
61 {
62 return (struct cfpkt *) skb;
63 }
64
cfpkt_fromnative(enum caif_direction dir,void * nativepkt)65 struct cfpkt *cfpkt_fromnative(enum caif_direction dir, void *nativepkt)
66 {
67 struct cfpkt *pkt = skb_to_pkt(nativepkt);
68 cfpkt_priv(pkt)->erronous = false;
69 return pkt;
70 }
71 EXPORT_SYMBOL(cfpkt_fromnative);
72
cfpkt_tonative(struct cfpkt * pkt)73 void *cfpkt_tonative(struct cfpkt *pkt)
74 {
75 return (void *) pkt;
76 }
77 EXPORT_SYMBOL(cfpkt_tonative);
78
cfpkt_create_pfx(u16 len,u16 pfx)79 static struct cfpkt *cfpkt_create_pfx(u16 len, u16 pfx)
80 {
81 struct sk_buff *skb;
82
83 skb = alloc_skb(len + pfx, GFP_ATOMIC);
84 if (unlikely(skb == NULL))
85 return NULL;
86
87 skb_reserve(skb, pfx);
88 return skb_to_pkt(skb);
89 }
90
cfpkt_create(u16 len)91 inline struct cfpkt *cfpkt_create(u16 len)
92 {
93 return cfpkt_create_pfx(len + PKT_POSTFIX, PKT_PREFIX);
94 }
95
cfpkt_destroy(struct cfpkt * pkt)96 void cfpkt_destroy(struct cfpkt *pkt)
97 {
98 struct sk_buff *skb = pkt_to_skb(pkt);
99 kfree_skb(skb);
100 }
101
cfpkt_more(struct cfpkt * pkt)102 inline bool cfpkt_more(struct cfpkt *pkt)
103 {
104 struct sk_buff *skb = pkt_to_skb(pkt);
105 return skb->len > 0;
106 }
107
cfpkt_peek_head(struct cfpkt * pkt,void * data,u16 len)108 int cfpkt_peek_head(struct cfpkt *pkt, void *data, u16 len)
109 {
110 struct sk_buff *skb = pkt_to_skb(pkt);
111 if (skb_headlen(skb) >= len) {
112 memcpy(data, skb->data, len);
113 return 0;
114 }
115 return !cfpkt_extr_head(pkt, data, len) &&
116 !cfpkt_add_head(pkt, data, len);
117 }
118
cfpkt_extr_head(struct cfpkt * pkt,void * data,u16 len)119 int cfpkt_extr_head(struct cfpkt *pkt, void *data, u16 len)
120 {
121 struct sk_buff *skb = pkt_to_skb(pkt);
122 u8 *from;
123 if (unlikely(is_erronous(pkt)))
124 return -EPROTO;
125
126 if (unlikely(len > skb->len)) {
127 PKT_ERROR(pkt, "read beyond end of packet\n");
128 return -EPROTO;
129 }
130
131 if (unlikely(len > skb_headlen(skb))) {
132 if (unlikely(skb_linearize(skb) != 0)) {
133 PKT_ERROR(pkt, "linearize failed\n");
134 return -EPROTO;
135 }
136 }
137 from = skb_pull(skb, len);
138 from -= len;
139 if (data)
140 memcpy(data, from, len);
141 return 0;
142 }
143 EXPORT_SYMBOL(cfpkt_extr_head);
144
cfpkt_extr_trail(struct cfpkt * pkt,void * dta,u16 len)145 int cfpkt_extr_trail(struct cfpkt *pkt, void *dta, u16 len)
146 {
147 struct sk_buff *skb = pkt_to_skb(pkt);
148 u8 *data = dta;
149 u8 *from;
150 if (unlikely(is_erronous(pkt)))
151 return -EPROTO;
152
153 if (unlikely(skb_linearize(skb) != 0)) {
154 PKT_ERROR(pkt, "linearize failed\n");
155 return -EPROTO;
156 }
157 if (unlikely(skb->data + len > skb_tail_pointer(skb))) {
158 PKT_ERROR(pkt, "read beyond end of packet\n");
159 return -EPROTO;
160 }
161 from = skb_tail_pointer(skb) - len;
162 skb_trim(skb, skb->len - len);
163 memcpy(data, from, len);
164 return 0;
165 }
166
cfpkt_pad_trail(struct cfpkt * pkt,u16 len)167 int cfpkt_pad_trail(struct cfpkt *pkt, u16 len)
168 {
169 return cfpkt_add_body(pkt, NULL, len);
170 }
171
cfpkt_add_body(struct cfpkt * pkt,const void * data,u16 len)172 int cfpkt_add_body(struct cfpkt *pkt, const void *data, u16 len)
173 {
174 struct sk_buff *skb = pkt_to_skb(pkt);
175 struct sk_buff *lastskb;
176 u8 *to;
177 u16 addlen = 0;
178
179
180 if (unlikely(is_erronous(pkt)))
181 return -EPROTO;
182
183 lastskb = skb;
184
185 /* Check whether we need to add space at the tail */
186 if (unlikely(skb_tailroom(skb) < len)) {
187 if (likely(len < PKT_LEN_WHEN_EXTENDING))
188 addlen = PKT_LEN_WHEN_EXTENDING;
189 else
190 addlen = len;
191 }
192
193 /* Check whether we need to change the SKB before writing to the tail */
194 if (unlikely((addlen > 0) || skb_cloned(skb) || skb_shared(skb))) {
195
196 /* Make sure data is writable */
197 if (unlikely(skb_cow_data(skb, addlen, &lastskb) < 0)) {
198 PKT_ERROR(pkt, "cow failed\n");
199 return -EPROTO;
200 }
201 }
202
203 /* All set to put the last SKB and optionally write data there. */
204 to = pskb_put(skb, lastskb, len);
205 if (likely(data))
206 memcpy(to, data, len);
207 return 0;
208 }
209
cfpkt_addbdy(struct cfpkt * pkt,u8 data)210 inline int cfpkt_addbdy(struct cfpkt *pkt, u8 data)
211 {
212 return cfpkt_add_body(pkt, &data, 1);
213 }
214
cfpkt_add_head(struct cfpkt * pkt,const void * data2,u16 len)215 int cfpkt_add_head(struct cfpkt *pkt, const void *data2, u16 len)
216 {
217 struct sk_buff *skb = pkt_to_skb(pkt);
218 struct sk_buff *lastskb;
219 u8 *to;
220 const u8 *data = data2;
221 int ret;
222 if (unlikely(is_erronous(pkt)))
223 return -EPROTO;
224 if (unlikely(skb_headroom(skb) < len)) {
225 PKT_ERROR(pkt, "no headroom\n");
226 return -EPROTO;
227 }
228
229 /* Make sure data is writable */
230 ret = skb_cow_data(skb, 0, &lastskb);
231 if (unlikely(ret < 0)) {
232 PKT_ERROR(pkt, "cow failed\n");
233 return ret;
234 }
235
236 to = skb_push(skb, len);
237 memcpy(to, data, len);
238 return 0;
239 }
240 EXPORT_SYMBOL(cfpkt_add_head);
241
cfpkt_add_trail(struct cfpkt * pkt,const void * data,u16 len)242 inline int cfpkt_add_trail(struct cfpkt *pkt, const void *data, u16 len)
243 {
244 return cfpkt_add_body(pkt, data, len);
245 }
246
cfpkt_getlen(struct cfpkt * pkt)247 inline u16 cfpkt_getlen(struct cfpkt *pkt)
248 {
249 struct sk_buff *skb = pkt_to_skb(pkt);
250 return skb->len;
251 }
252
cfpkt_iterate(struct cfpkt * pkt,u16 (* iter_func)(u16,void *,u16),u16 data)253 int cfpkt_iterate(struct cfpkt *pkt,
254 u16 (*iter_func)(u16, void *, u16),
255 u16 data)
256 {
257 /*
258 * Don't care about the performance hit of linearizing,
259 * Checksum should not be used on high-speed interfaces anyway.
260 */
261 if (unlikely(is_erronous(pkt)))
262 return -EPROTO;
263 if (unlikely(skb_linearize(&pkt->skb) != 0)) {
264 PKT_ERROR(pkt, "linearize failed\n");
265 return -EPROTO;
266 }
267 return iter_func(data, pkt->skb.data, cfpkt_getlen(pkt));
268 }
269
cfpkt_setlen(struct cfpkt * pkt,u16 len)270 int cfpkt_setlen(struct cfpkt *pkt, u16 len)
271 {
272 struct sk_buff *skb = pkt_to_skb(pkt);
273
274
275 if (unlikely(is_erronous(pkt)))
276 return -EPROTO;
277
278 if (likely(len <= skb->len)) {
279 if (unlikely(skb->data_len))
280 ___pskb_trim(skb, len);
281 else
282 skb_trim(skb, len);
283
284 return cfpkt_getlen(pkt);
285 }
286
287 /* Need to expand SKB */
288 if (unlikely(!cfpkt_pad_trail(pkt, len - skb->len)))
289 PKT_ERROR(pkt, "skb_pad_trail failed\n");
290
291 return cfpkt_getlen(pkt);
292 }
293
cfpkt_append(struct cfpkt * dstpkt,struct cfpkt * addpkt,u16 expectlen)294 struct cfpkt *cfpkt_append(struct cfpkt *dstpkt,
295 struct cfpkt *addpkt,
296 u16 expectlen)
297 {
298 struct sk_buff *dst = pkt_to_skb(dstpkt);
299 struct sk_buff *add = pkt_to_skb(addpkt);
300 u16 addlen = skb_headlen(add);
301 u16 neededtailspace;
302 struct sk_buff *tmp;
303 u16 dstlen;
304 u16 createlen;
305 if (unlikely(is_erronous(dstpkt) || is_erronous(addpkt))) {
306 return dstpkt;
307 }
308 if (expectlen > addlen)
309 neededtailspace = expectlen;
310 else
311 neededtailspace = addlen;
312
313 if (dst->tail + neededtailspace > dst->end) {
314 /* Create a dumplicate of 'dst' with more tail space */
315 struct cfpkt *tmppkt;
316 dstlen = skb_headlen(dst);
317 createlen = dstlen + neededtailspace;
318 tmppkt = cfpkt_create(createlen + PKT_PREFIX + PKT_POSTFIX);
319 if (tmppkt == NULL)
320 return NULL;
321 tmp = pkt_to_skb(tmppkt);
322 skb_put_data(tmp, dst->data, dstlen);
323 cfpkt_destroy(dstpkt);
324 dst = tmp;
325 }
326 skb_put_data(dst, add->data, skb_headlen(add));
327 cfpkt_destroy(addpkt);
328 return skb_to_pkt(dst);
329 }
330
cfpkt_split(struct cfpkt * pkt,u16 pos)331 struct cfpkt *cfpkt_split(struct cfpkt *pkt, u16 pos)
332 {
333 struct sk_buff *skb2;
334 struct sk_buff *skb = pkt_to_skb(pkt);
335 struct cfpkt *tmppkt;
336 u8 *split = skb->data + pos;
337 u16 len2nd = skb_tail_pointer(skb) - split;
338
339 if (unlikely(is_erronous(pkt)))
340 return NULL;
341
342 if (skb->data + pos > skb_tail_pointer(skb)) {
343 PKT_ERROR(pkt, "trying to split beyond end of packet\n");
344 return NULL;
345 }
346
347 /* Create a new packet for the second part of the data */
348 tmppkt = cfpkt_create_pfx(len2nd + PKT_PREFIX + PKT_POSTFIX,
349 PKT_PREFIX);
350 if (tmppkt == NULL)
351 return NULL;
352 skb2 = pkt_to_skb(tmppkt);
353
354
355 if (skb2 == NULL)
356 return NULL;
357
358 skb_put_data(skb2, split, len2nd);
359
360 /* Reduce the length of the original packet */
361 skb_trim(skb, pos);
362
363 skb2->priority = skb->priority;
364 return skb_to_pkt(skb2);
365 }
366
cfpkt_erroneous(struct cfpkt * pkt)367 bool cfpkt_erroneous(struct cfpkt *pkt)
368 {
369 return cfpkt_priv(pkt)->erronous;
370 }
371
cfpkt_info(struct cfpkt * pkt)372 struct caif_payload_info *cfpkt_info(struct cfpkt *pkt)
373 {
374 return (struct caif_payload_info *)&pkt_to_skb(pkt)->cb;
375 }
376 EXPORT_SYMBOL(cfpkt_info);
377
cfpkt_set_prio(struct cfpkt * pkt,int prio)378 void cfpkt_set_prio(struct cfpkt *pkt, int prio)
379 {
380 pkt_to_skb(pkt)->priority = prio;
381 }
382 EXPORT_SYMBOL(cfpkt_set_prio);
383