1 /* 2 * Copyright (C) ST-Ericsson AB 2010 3 * Author: Sjur Brendeland 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 46 static inline struct cfpkt_priv_data *cfpkt_priv(struct cfpkt *pkt) 47 { 48 return (struct cfpkt_priv_data *) pkt->skb.cb; 49 } 50 51 static inline bool is_erronous(struct cfpkt *pkt) 52 { 53 return cfpkt_priv(pkt)->erronous; 54 } 55 56 static inline struct sk_buff *pkt_to_skb(struct cfpkt *pkt) 57 { 58 return &pkt->skb; 59 } 60 61 static inline struct cfpkt *skb_to_pkt(struct sk_buff *skb) 62 { 63 return (struct cfpkt *) skb; 64 } 65 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 74 void *cfpkt_tonative(struct cfpkt *pkt) 75 { 76 return (void *) pkt; 77 } 78 EXPORT_SYMBOL(cfpkt_tonative); 79 80 static struct cfpkt *cfpkt_create_pfx(u16 len, u16 pfx) 81 { 82 struct sk_buff *skb; 83 84 skb = alloc_skb(len + pfx, GFP_ATOMIC); 85 if (unlikely(skb == NULL)) 86 return NULL; 87 88 skb_reserve(skb, pfx); 89 return skb_to_pkt(skb); 90 } 91 92 inline struct cfpkt *cfpkt_create(u16 len) 93 { 94 return cfpkt_create_pfx(len + PKT_POSTFIX, PKT_PREFIX); 95 } 96 97 void cfpkt_destroy(struct cfpkt *pkt) 98 { 99 struct sk_buff *skb = pkt_to_skb(pkt); 100 kfree_skb(skb); 101 } 102 103 inline bool cfpkt_more(struct cfpkt *pkt) 104 { 105 struct sk_buff *skb = pkt_to_skb(pkt); 106 return skb->len > 0; 107 } 108 109 int cfpkt_peek_head(struct cfpkt *pkt, void *data, u16 len) 110 { 111 struct sk_buff *skb = pkt_to_skb(pkt); 112 if (skb_headlen(skb) >= len) { 113 memcpy(data, skb->data, len); 114 return 0; 115 } 116 return !cfpkt_extr_head(pkt, data, len) && 117 !cfpkt_add_head(pkt, data, len); 118 } 119 120 int cfpkt_extr_head(struct cfpkt *pkt, void *data, u16 len) 121 { 122 struct sk_buff *skb = pkt_to_skb(pkt); 123 u8 *from; 124 if (unlikely(is_erronous(pkt))) 125 return -EPROTO; 126 127 if (unlikely(len > skb->len)) { 128 PKT_ERROR(pkt, "read beyond end of packet\n"); 129 return -EPROTO; 130 } 131 132 if (unlikely(len > skb_headlen(skb))) { 133 if (unlikely(skb_linearize(skb) != 0)) { 134 PKT_ERROR(pkt, "linearize failed\n"); 135 return -EPROTO; 136 } 137 } 138 from = skb_pull(skb, len); 139 from -= len; 140 if (data) 141 memcpy(data, from, len); 142 return 0; 143 } 144 EXPORT_SYMBOL(cfpkt_extr_head); 145 146 int cfpkt_extr_trail(struct cfpkt *pkt, void *dta, u16 len) 147 { 148 struct sk_buff *skb = pkt_to_skb(pkt); 149 u8 *data = dta; 150 u8 *from; 151 if (unlikely(is_erronous(pkt))) 152 return -EPROTO; 153 154 if (unlikely(skb_linearize(skb) != 0)) { 155 PKT_ERROR(pkt, "linearize failed\n"); 156 return -EPROTO; 157 } 158 if (unlikely(skb->data + len > skb_tail_pointer(skb))) { 159 PKT_ERROR(pkt, "read beyond end of packet\n"); 160 return -EPROTO; 161 } 162 from = skb_tail_pointer(skb) - len; 163 skb_trim(skb, skb->len - len); 164 memcpy(data, from, len); 165 return 0; 166 } 167 168 int cfpkt_pad_trail(struct cfpkt *pkt, u16 len) 169 { 170 return cfpkt_add_body(pkt, NULL, len); 171 } 172 173 int cfpkt_add_body(struct cfpkt *pkt, const void *data, u16 len) 174 { 175 struct sk_buff *skb = pkt_to_skb(pkt); 176 struct sk_buff *lastskb; 177 u8 *to; 178 u16 addlen = 0; 179 180 181 if (unlikely(is_erronous(pkt))) 182 return -EPROTO; 183 184 lastskb = skb; 185 186 /* Check whether we need to add space at the tail */ 187 if (unlikely(skb_tailroom(skb) < len)) { 188 if (likely(len < PKT_LEN_WHEN_EXTENDING)) 189 addlen = PKT_LEN_WHEN_EXTENDING; 190 else 191 addlen = len; 192 } 193 194 /* Check whether we need to change the SKB before writing to the tail */ 195 if (unlikely((addlen > 0) || skb_cloned(skb) || skb_shared(skb))) { 196 197 /* Make sure data is writable */ 198 if (unlikely(skb_cow_data(skb, addlen, &lastskb) < 0)) { 199 PKT_ERROR(pkt, "cow failed\n"); 200 return -EPROTO; 201 } 202 } 203 204 /* All set to put the last SKB and optionally write data there. */ 205 to = pskb_put(skb, lastskb, len); 206 if (likely(data)) 207 memcpy(to, data, len); 208 return 0; 209 } 210 211 inline int cfpkt_addbdy(struct cfpkt *pkt, u8 data) 212 { 213 return cfpkt_add_body(pkt, &data, 1); 214 } 215 216 int cfpkt_add_head(struct cfpkt *pkt, const void *data2, u16 len) 217 { 218 struct sk_buff *skb = pkt_to_skb(pkt); 219 struct sk_buff *lastskb; 220 u8 *to; 221 const u8 *data = data2; 222 int ret; 223 if (unlikely(is_erronous(pkt))) 224 return -EPROTO; 225 if (unlikely(skb_headroom(skb) < len)) { 226 PKT_ERROR(pkt, "no headroom\n"); 227 return -EPROTO; 228 } 229 230 /* Make sure data is writable */ 231 ret = skb_cow_data(skb, 0, &lastskb); 232 if (unlikely(ret < 0)) { 233 PKT_ERROR(pkt, "cow failed\n"); 234 return ret; 235 } 236 237 to = skb_push(skb, len); 238 memcpy(to, data, len); 239 return 0; 240 } 241 EXPORT_SYMBOL(cfpkt_add_head); 242 243 inline int cfpkt_add_trail(struct cfpkt *pkt, const void *data, u16 len) 244 { 245 return cfpkt_add_body(pkt, data, len); 246 } 247 248 inline u16 cfpkt_getlen(struct cfpkt *pkt) 249 { 250 struct sk_buff *skb = pkt_to_skb(pkt); 251 return skb->len; 252 } 253 254 int cfpkt_iterate(struct cfpkt *pkt, 255 u16 (*iter_func)(u16, void *, u16), 256 u16 data) 257 { 258 /* 259 * Don't care about the performance hit of linearizing, 260 * Checksum should not be used on high-speed interfaces anyway. 261 */ 262 if (unlikely(is_erronous(pkt))) 263 return -EPROTO; 264 if (unlikely(skb_linearize(&pkt->skb) != 0)) { 265 PKT_ERROR(pkt, "linearize failed\n"); 266 return -EPROTO; 267 } 268 return iter_func(data, pkt->skb.data, cfpkt_getlen(pkt)); 269 } 270 271 int cfpkt_setlen(struct cfpkt *pkt, u16 len) 272 { 273 struct sk_buff *skb = pkt_to_skb(pkt); 274 275 276 if (unlikely(is_erronous(pkt))) 277 return -EPROTO; 278 279 if (likely(len <= skb->len)) { 280 if (unlikely(skb->data_len)) 281 ___pskb_trim(skb, len); 282 else 283 skb_trim(skb, len); 284 285 return cfpkt_getlen(pkt); 286 } 287 288 /* Need to expand SKB */ 289 if (unlikely(!cfpkt_pad_trail(pkt, len - skb->len))) 290 PKT_ERROR(pkt, "skb_pad_trail failed\n"); 291 292 return cfpkt_getlen(pkt); 293 } 294 295 struct cfpkt *cfpkt_append(struct cfpkt *dstpkt, 296 struct cfpkt *addpkt, 297 u16 expectlen) 298 { 299 struct sk_buff *dst = pkt_to_skb(dstpkt); 300 struct sk_buff *add = pkt_to_skb(addpkt); 301 u16 addlen = skb_headlen(add); 302 u16 neededtailspace; 303 struct sk_buff *tmp; 304 u16 dstlen; 305 u16 createlen; 306 if (unlikely(is_erronous(dstpkt) || is_erronous(addpkt))) { 307 return dstpkt; 308 } 309 if (expectlen > addlen) 310 neededtailspace = expectlen; 311 else 312 neededtailspace = addlen; 313 314 if (dst->tail + neededtailspace > dst->end) { 315 /* Create a dumplicate of 'dst' with more tail space */ 316 struct cfpkt *tmppkt; 317 dstlen = skb_headlen(dst); 318 createlen = dstlen + neededtailspace; 319 tmppkt = cfpkt_create(createlen + PKT_PREFIX + PKT_POSTFIX); 320 if (tmppkt == NULL) 321 return NULL; 322 tmp = pkt_to_skb(tmppkt); 323 skb_set_tail_pointer(tmp, dstlen); 324 tmp->len = dstlen; 325 memcpy(tmp->data, dst->data, dstlen); 326 cfpkt_destroy(dstpkt); 327 dst = tmp; 328 } 329 memcpy(skb_tail_pointer(dst), add->data, skb_headlen(add)); 330 cfpkt_destroy(addpkt); 331 dst->tail += addlen; 332 dst->len += addlen; 333 return skb_to_pkt(dst); 334 } 335 336 struct cfpkt *cfpkt_split(struct cfpkt *pkt, u16 pos) 337 { 338 struct sk_buff *skb2; 339 struct sk_buff *skb = pkt_to_skb(pkt); 340 struct cfpkt *tmppkt; 341 u8 *split = skb->data + pos; 342 u16 len2nd = skb_tail_pointer(skb) - split; 343 344 if (unlikely(is_erronous(pkt))) 345 return NULL; 346 347 if (skb->data + pos > skb_tail_pointer(skb)) { 348 PKT_ERROR(pkt, "trying to split beyond end of packet\n"); 349 return NULL; 350 } 351 352 /* Create a new packet for the second part of the data */ 353 tmppkt = cfpkt_create_pfx(len2nd + PKT_PREFIX + PKT_POSTFIX, 354 PKT_PREFIX); 355 if (tmppkt == NULL) 356 return NULL; 357 skb2 = pkt_to_skb(tmppkt); 358 359 360 if (skb2 == NULL) 361 return NULL; 362 363 /* Reduce the length of the original packet */ 364 skb_set_tail_pointer(skb, pos); 365 skb->len = pos; 366 367 memcpy(skb2->data, split, len2nd); 368 skb2->tail += len2nd; 369 skb2->len += len2nd; 370 skb2->priority = skb->priority; 371 return skb_to_pkt(skb2); 372 } 373 374 bool cfpkt_erroneous(struct cfpkt *pkt) 375 { 376 return cfpkt_priv(pkt)->erronous; 377 } 378 379 struct caif_payload_info *cfpkt_info(struct cfpkt *pkt) 380 { 381 return (struct caif_payload_info *)&pkt_to_skb(pkt)->cb; 382 } 383 EXPORT_SYMBOL(cfpkt_info); 384 385 void cfpkt_set_prio(struct cfpkt *pkt, int prio) 386 { 387 pkt_to_skb(pkt)->priority = prio; 388 } 389 EXPORT_SYMBOL(cfpkt_set_prio); 390