trafgen_proto.c

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * Subject to the GPL, version 2.
   4  */
   5
   6 #include <stddef.h>
   7 #include <string.h>
   8 #include <netinet/in.h>
   9 #include <linux/if_ether.h>
  10
  11 #include "dev.h"
  12 #include "xmalloc.h"
  13 #include "trafgen_conf.h"
  14 #include "trafgen_l2.h"
  15 #include "trafgen_l3.h"
  16 #include "trafgen_l4.h"
  17 #include "trafgen_proto.h"
  18
  19 #define field_shift_and_mask(f, v) (((v) << (f)->shift) & \
  20                 ((f)->mask ? (f)->mask : (0xffffffff)))
  21
  22 #define field_unmask_and_unshift(f, v) (((v) & \
  23                 ((f)->mask ? (f)->mask : (0xffffffff))) >> (f)->shift)
  24
  25 static struct proto_ctx ctx;
  26
  27 #define PROTO_MAX_LAYERS        16
  28
  29 static struct proto_hdr *headers[PROTO_MAX_LAYERS];
  30 static size_t headers_count;
  31
  32 static struct proto_hdr *registered;
  33
  34 struct proto_hdr *proto_lower_header(struct proto_hdr *hdr)
  35 {
  36         struct proto_hdr *lower = NULL;
  37         size_t i;
  38
  39         if (headers_count == 0)
  40                 return NULL;
  41
  42         for (i = 1, lower = headers[0]; i < headers_count; i++) {
  43                 if (headers[i] == hdr)
  44                         return headers[i - 1];
  45         }
  46
  47         return lower;
  48 }
  49
  50 uint8_t *proto_header_ptr(struct proto_hdr *hdr)
  51 {
  52         return &current_packet()->payload[hdr->pkt_offset];
  53 }
  54
  55 static struct proto_hdr *proto_header_by_id(enum proto_id id)
  56 {
  57         struct proto_hdr *p = registered;
  58
  59         for (; p; p = p->next)
  60                 if (p->id == id)
  61                         return p;
  62
  63         panic("Can't lookup proto by id %u\n", id);
  64 }
  65
  66 void proto_header_register(struct proto_hdr *hdr)
  67 {
  68         hdr->next = registered;
  69         registered = hdr;
  70
  71         hdr->fields = NULL;
  72         hdr->fields_count = 0;
  73 }
  74
  75 static void proto_fields_realloc(struct proto_hdr *hdr, size_t count)
  76 {
  77         hdr->fields = xrealloc(hdr->fields, count * sizeof(*hdr->fields));
  78         hdr->fields_count = count;
  79 }
  80
  81 void proto_header_fields_add(struct proto_hdr *hdr,
  82                              const struct proto_field *fields, size_t count)
  83 {
  84         struct packet *pkt = current_packet();
  85         struct proto_field *f;
  86         int i;
  87
  88         if (!hdr->fields)
  89                 hdr->pkt_offset = pkt->len;
  90
  91         proto_fields_realloc(hdr, hdr->fields_count + count);
  92
  93         for (i = 0; count >= 1; count--, i++) {
  94                 f = &hdr->fields[hdr->fields_count - count];
  95
  96                 f->id = fields[i].id;
  97                 f->len = fields[i].len;
  98                 f->is_set = false;
  99                 f->shift = fields[i].shift;
 100                 f->mask = fields[i].mask;
 101                 f->pkt_offset = hdr->pkt_offset + fields[i].offset;
 102
 103                 if (f->pkt_offset + f->len > pkt->len) {
 104                         hdr->len += f->len;
 105                         set_fill(0, (f->pkt_offset + f->len) - pkt->len);
 106                 }
 107         }
 108 }
 109
 110 static struct proto_field *proto_field_by_id(struct proto_hdr *hdr, uint32_t fid)
 111 {
 112         int i;
 113
 114         for (i = 0; i < hdr->fields_count; i++)
 115                 if (hdr->fields[i].id == fid)
 116                         return &hdr->fields[i];
 117
 118         panic("Failed lookup field id %u for proto id %u\n", fid, hdr->id);
 119 }
 120
 121 bool proto_field_is_set(struct proto_hdr *hdr, uint32_t fid)
 122 {
 123         struct proto_field *field = proto_field_by_id(hdr, fid);
 124
 125         return field ? field->is_set : false;
 126 }
 127
 128 struct proto_hdr *proto_header_init(enum proto_id pid)
 129 {
 130         struct proto_hdr *hdr = proto_header_by_id(pid);
 131         struct proto_hdr *new_hdr;
 132
 133         bug_on(headers_count >= PROTO_MAX_LAYERS);
 134
 135         new_hdr = xmalloc(sizeof(*new_hdr));
 136         memcpy(new_hdr, hdr, sizeof(*new_hdr));
 137
 138         if (new_hdr->header_init)
 139                 new_hdr->header_init(new_hdr);
 140
 141         headers[headers_count++] = new_hdr;
 142         return new_hdr;
 143 }
 144
 145 void proto_header_finish(struct proto_hdr *hdr)
 146 {
 147         if (hdr && hdr->header_finish)
 148                 hdr->header_finish(hdr);
 149 }
 150
 151 struct proto_hdr *proto_lower_default_add(struct proto_hdr *hdr,
 152                                           enum proto_id pid)
 153 {
 154         struct proto_hdr *current;
 155
 156         if (headers_count > 0) {
 157                 current = headers[headers_count - 1];
 158
 159                 if (current->layer >= proto_header_by_id(pid)->layer)
 160                         goto set_proto;
 161                 if (current->id == pid)
 162                         goto set_proto;
 163         }
 164
 165         current = proto_header_init(pid);
 166
 167 set_proto:
 168         if (current->set_next_proto)
 169                 current->set_next_proto(current, hdr->id);
 170
 171         return current;
 172 }
 173
 174 static void __proto_field_set_bytes(struct proto_hdr *hdr, uint32_t fid,
 175                                     uint8_t *bytes, bool is_default, bool is_be)
 176 {
 177         struct proto_field *field;
 178         uint8_t *payload, *p8;
 179         uint16_t *p16;
 180         uint32_t *p32;
 181         uint32_t v32;
 182         uint16_t v16;
 183         uint8_t v8;
 184
 185         field = proto_field_by_id(hdr, fid);
 186
 187         if (is_default && field->is_set)
 188                 return;
 189
 190         payload = &current_packet()->payload[field->pkt_offset];
 191
 192         if (field->len == 1) {
 193                 p8 = payload;
 194                 *p8 = field->mask ? *p8 & ~field->mask : *p8;
 195
 196                 v8 = field_shift_and_mask(field, *bytes);
 197                 v8 = field->mask ? (v8 | *p8) : v8;
 198
 199                 bytes = &v8;
 200         } else if (field->len == 2) {
 201                 p16 = (uint16_t *)payload;
 202                 *p16 = be16_to_cpu(*p16);
 203                 *p16 = cpu_to_be16(field->mask ? *p16 & ~field->mask : *p16);
 204
 205                 v16 = field_shift_and_mask(field, *(uint16_t *)bytes);
 206                 v16 = is_be ? cpu_to_be16(v16) : v16;
 207                 v16 = field->mask ? (v16 | *p16) : v16;
 208
 209                 bytes = (uint8_t *)&v16;
 210         } else if (field->len == 4) {
 211                 p32 = (uint32_t *)payload;
 212                 *p32 = be32_to_cpu(*p32);
 213                 *p32 = cpu_to_be32(field->mask ? *p32 & ~field->mask : *p32);
 214
 215                 v32 = field_shift_and_mask(field, *(uint32_t *)bytes);
 216                 v32 = is_be ? cpu_to_be32(v32) : v32;
 217                 v32 = field->mask ? (v32 | *p32) : v32;
 218
 219                 bytes = (uint8_t *)&v32;
 220         }
 221
 222         memcpy(payload, bytes, field->len);
 223
 224         if (!is_default)
 225                 field->is_set = true;
 226 }
 227
 228 void proto_field_set_bytes(struct proto_hdr *hdr, uint32_t fid, uint8_t *bytes)
 229 {
 230         __proto_field_set_bytes(hdr, fid, bytes, false, false);
 231 }
 232
 233 static uint8_t *__proto_field_get_bytes(struct proto_field *field)
 234 {
 235         struct packet *pkt = current_packet();
 236
 237         return &pkt->payload[field->pkt_offset];
 238 }
 239
 240 void proto_field_set_u8(struct proto_hdr *hdr, uint32_t fid, uint8_t val)
 241 {
 242         proto_field_set_bytes(hdr, fid, (uint8_t *)&val);
 243 }
 244
 245 uint8_t proto_field_get_u8(struct proto_hdr *hdr, uint32_t fid)
 246 {
 247         struct proto_field *field = proto_field_by_id(hdr, fid);
 248         uint8_t val = *__proto_field_get_bytes(field);
 249
 250         return field_unmask_and_unshift(field, val);
 251 }
 252
 253 void proto_field_set_u16(struct proto_hdr *hdr, uint32_t fid, uint16_t val)
 254 {
 255         proto_field_set_bytes(hdr, fid, (uint8_t *)&val);
 256 }
 257
 258 uint16_t proto_field_get_u16(struct proto_hdr *hdr, uint32_t fid)
 259 {
 260         struct proto_field *field = proto_field_by_id(hdr, fid);
 261         uint16_t val = *(uint16_t *)__proto_field_get_bytes(field);
 262
 263         return field_unmask_and_unshift(field, be16_to_cpu(val));
 264 }
 265
 266 void proto_field_set_u32(struct proto_hdr *hdr, uint32_t fid, uint32_t val)
 267 {
 268         proto_field_set_bytes(hdr, fid, (uint8_t *)&val);
 269 }
 270
 271 uint32_t proto_field_get_u32(struct proto_hdr *hdr, uint32_t fid)
 272 {
 273         struct proto_field *field = proto_field_by_id(hdr, fid);
 274         uint32_t val = *(uint32_t *)__proto_field_get_bytes(field);
 275
 276         return field_unmask_and_unshift(field, be32_to_cpu(val));
 277 }
 278
 279 void proto_field_set_default_bytes(struct proto_hdr *hdr, uint32_t fid, uint8_t *bytes)
 280 {
 281         __proto_field_set_bytes(hdr, fid, bytes, true, false);
 282 }
 283
 284 void proto_field_set_default_u8(struct proto_hdr *hdr, uint32_t fid, uint8_t val)
 285 {
 286         __proto_field_set_bytes(hdr, fid, (uint8_t *)&val, true, false);
 287 }
 288
 289 void proto_field_set_default_u16(struct proto_hdr *hdr, uint32_t fid, uint16_t val)
 290 {
 291         __proto_field_set_bytes(hdr, fid, (uint8_t *)&val, true, false);
 292 }
 293
 294 void proto_field_set_default_u32(struct proto_hdr *hdr, uint32_t fid, uint32_t val)
 295 {
 296         __proto_field_set_bytes(hdr, fid, (uint8_t *)&val, true, false);
 297 }
 298
 299 void proto_field_set_be16(struct proto_hdr *hdr, uint32_t fid, uint16_t val)
 300 {
 301         __proto_field_set_bytes(hdr, fid, (uint8_t *)&val, false, true);
 302 }
 303
 304 void proto_field_set_be32(struct proto_hdr *hdr, uint32_t fid, uint32_t val)
 305 {
 306         __proto_field_set_bytes(hdr, fid, (uint8_t *)&val, false, true);
 307 }
 308
 309 void proto_field_set_default_be16(struct proto_hdr *hdr, uint32_t fid, uint16_t val)
 310 {
 311         __proto_field_set_bytes(hdr, fid, (uint8_t *)&val, true, true);
 312 }
 313
 314 void proto_field_set_default_be32(struct proto_hdr *hdr, uint32_t fid, uint32_t val)
 315 {
 316         __proto_field_set_bytes(hdr, fid, (uint8_t *)&val, true, true);
 317 }
 318
 319 static void __proto_field_set_dev_mac(struct proto_hdr *hdr, uint32_t fid,
 320                                       bool is_default)
 321 {
 322         uint8_t mac[ETH_ALEN];
 323         int ret;
 324
 325         if (proto_field_is_set(hdr, fid))
 326                 return;
 327
 328         if (!hdr->ctx->dev)
 329                 panic("Device is not specified\n");
 330
 331         ret = device_hw_address(hdr->ctx->dev, mac, sizeof(mac));
 332         if (ret < 0)
 333                 panic("Could not get device hw address\n");
 334
 335         __proto_field_set_bytes(hdr, fid, mac, is_default, false);
 336 }
 337
 338 void proto_field_set_dev_mac(struct proto_hdr *hdr, uint32_t fid)
 339 {
 340         __proto_field_set_dev_mac(hdr, fid, false);
 341 }
 342
 343 void proto_field_set_default_dev_mac(struct proto_hdr *hdr, uint32_t fid)
 344 {
 345         __proto_field_set_dev_mac(hdr, fid, true);
 346 }
 347
 348 static void __proto_field_set_dev_ipv4(struct proto_hdr *hdr, uint32_t fid,
 349                                        bool is_default)
 350 {
 351         struct sockaddr_storage ss = { };
 352         struct sockaddr_in *ss4;
 353         int ret;
 354
 355         if (proto_field_is_set(hdr, fid))
 356                 return;
 357
 358         ret = device_address(hdr->ctx->dev, AF_INET, &ss);
 359         if (ret < 0)
 360                 panic("Could not get device IPv4 address\n");
 361
 362         ss4 = (struct sockaddr_in *) &ss;
 363         __proto_field_set_bytes(hdr, fid, (uint8_t *)&ss4->sin_addr.s_addr, is_default, false);
 364 }
 365
 366 void proto_field_set_dev_ipv4(struct proto_hdr *hdr, uint32_t fid)
 367 {
 368         __proto_field_set_dev_ipv4(hdr, fid, false);
 369 }
 370
 371 void proto_field_set_default_dev_ipv4(struct proto_hdr *hdr, uint32_t fid)
 372 {
 373         __proto_field_set_dev_ipv4(hdr, fid, true);
 374 }
 375
 376 static void __proto_field_set_dev_ipv6(struct proto_hdr *hdr, uint32_t fid,
 377                                        bool is_default)
 378 {
 379         struct sockaddr_storage ss = { };
 380         struct sockaddr_in6 *ss6;
 381         int ret;
 382
 383         if (proto_field_is_set(hdr, fid))
 384                 return;
 385
 386         ret = device_address(hdr->ctx->dev, AF_INET6, &ss);
 387         if (ret < 0)
 388                 panic("Could not get device IPv6 address\n");
 389
 390         ss6 = (struct sockaddr_in6 *) &ss;
 391         __proto_field_set_bytes(hdr, fid, (uint8_t *)&ss6->sin6_addr.s6_addr, is_default, false);
 392 }
 393
 394 void proto_field_set_dev_ipv6(struct proto_hdr *hdr, uint32_t fid)
 395 {
 396         __proto_field_set_dev_ipv6(hdr, fid, false);
 397 }
 398
 399 void proto_field_set_default_dev_ipv6(struct proto_hdr *hdr, uint32_t fid)
 400 {
 401         __proto_field_set_dev_ipv6(hdr, fid, true);
 402 }
 403
 404 void protos_init(const char *dev)
 405 {
 406         struct proto_hdr *p;
 407
 408         ctx.dev = dev;
 409
 410         protos_l2_init();
 411         protos_l3_init();
 412         protos_l4_init();
 413
 414         for (p = registered; p; p = p->next)
 415                 p->ctx = &ctx;
 416 }
 417
 418 void proto_packet_finish(void)
 419 {
 420         ssize_t i;
 421
 422         /* Go down from upper layers to do last calculations (checksum) */
 423         for (i = headers_count - 1; i >= 0; i--) {
 424                 struct proto_hdr *p = headers[i];
 425
 426                 if (p->packet_finish)
 427                         p->packet_finish(p);
 428         }
 429
 430         for (i = 0; i < headers_count; i++) {
 431                 struct proto_hdr *p = headers[i];
 432
 433                 if (p->fields) {
 434                         xfree(p->fields);
 435                         p->fields_count = 0;
 436                 }
 437
 438                 xfree(headers[i]);
 439         }
 440
 441         headers_count = 0;
 442 }