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                         set_fill(0, (f->pkt_offset + f->len) - pkt->len);
 105         }
 106 }
 107
 108 static struct proto_field *proto_field_by_id(struct proto_hdr *hdr, uint32_t fid)
 109 {
 110         int i;
 111
 112         for (i = 0; i < hdr->fields_count; i++)
 113                 if (hdr->fields[i].id == fid)
 114                         return &hdr->fields[i];
 115
 116         panic("Failed lookup field id %u for proto id %u\n", fid, hdr->id);
 117 }
 118
 119 bool proto_field_is_set(struct proto_hdr *hdr, uint32_t fid)
 120 {
 121         struct proto_field *field = proto_field_by_id(hdr, fid);
 122
 123         return field ? field->is_set : false;
 124 }
 125
 126 struct proto_hdr *proto_header_init(enum proto_id pid)
 127 {
 128         struct proto_hdr *hdr = proto_header_by_id(pid);
 129         struct proto_hdr *new_hdr;
 130
 131         bug_on(headers_count >= PROTO_MAX_LAYERS);
 132
 133         new_hdr = xmalloc(sizeof(*new_hdr));
 134         memcpy(new_hdr, hdr, sizeof(*new_hdr));
 135
 136         if (new_hdr->header_init)
 137                 new_hdr->header_init(new_hdr);
 138
 139         headers[headers_count++] = new_hdr;
 140         return new_hdr;
 141 }
 142
 143 void proto_header_finish(struct proto_hdr *hdr)
 144 {
 145         if (hdr && hdr->header_finish)
 146                 hdr->header_finish(hdr);
 147 }
 148
 149 struct proto_hdr *proto_lower_default_add(struct proto_hdr *hdr,
 150                                           enum proto_id pid)
 151 {
 152         struct proto_hdr *current;
 153
 154         if (headers_count > 0) {
 155                 current = headers[headers_count - 1];
 156
 157                 if (current->layer >= proto_header_by_id(pid)->layer)
 158                         goto set_proto;
 159                 if (current->id == pid)
 160                         goto set_proto;
 161         }
 162
 163         current = proto_header_init(pid);
 164
 165 set_proto:
 166         if (current->set_next_proto)
 167                 current->set_next_proto(current, hdr->id);
 168
 169         return current;
 170 }
 171
 172 static void __proto_field_set_bytes(struct proto_hdr *hdr, uint32_t fid,
 173                                     uint8_t *bytes, bool is_default, bool is_be)
 174 {
 175         struct proto_field *field;
 176         uint8_t *payload, *p8;
 177         uint16_t *p16;
 178         uint32_t *p32;
 179         uint32_t v32;
 180         uint16_t v16;
 181         uint8_t v8;
 182
 183         field = proto_field_by_id(hdr, fid);
 184
 185         if (is_default && field->is_set)
 186                 return;
 187
 188         payload = &current_packet()->payload[field->pkt_offset];
 189
 190         if (field->len == 1) {
 191                 p8 = payload;
 192                 *p8 = field->mask ? *p8 & ~field->mask : *p8;
 193
 194                 v8 = field_shift_and_mask(field, *bytes);
 195                 v8 = field->mask ? (v8 | *p8) : v8;
 196
 197                 bytes = &v8;
 198         } else if (field->len == 2) {
 199                 p16 = (uint16_t *)payload;
 200                 *p16 = be16_to_cpu(*p16);
 201                 *p16 = cpu_to_be16(field->mask ? *p16 & ~field->mask : *p16);
 202
 203                 v16 = field_shift_and_mask(field, *(uint16_t *)bytes);
 204                 v16 = is_be ? cpu_to_be16(v16) : v16;
 205                 v16 = field->mask ? (v16 | *p16) : v16;
 206
 207                 bytes = (uint8_t *)&v16;
 208         } else if (field->len == 4) {
 209                 p32 = (uint32_t *)payload;
 210                 *p32 = be32_to_cpu(*p32);
 211                 *p32 = cpu_to_be32(field->mask ? *p32 & ~field->mask : *p32);
 212
 213                 v32 = field_shift_and_mask(field, *(uint32_t *)bytes);
 214                 v32 = is_be ? cpu_to_be32(v32) : v32;
 215                 v32 = field->mask ? (v32 | *p32) : v32;
 216
 217                 bytes = (uint8_t *)&v32;
 218         }
 219
 220         memcpy(payload, bytes, field->len);
 221
 222         if (!is_default)
 223                 field->is_set = true;
 224 }
 225
 226 void proto_field_set_bytes(struct proto_hdr *hdr, uint32_t fid, uint8_t *bytes)
 227 {
 228         __proto_field_set_bytes(hdr, fid, bytes, false, false);
 229 }
 230
 231 static uint8_t *__proto_field_get_bytes(struct proto_field *field)
 232 {
 233         struct packet *pkt = current_packet();
 234
 235         return &pkt->payload[field->pkt_offset];
 236 }
 237
 238 void proto_field_set_u8(struct proto_hdr *hdr, uint32_t fid, uint8_t val)
 239 {
 240         proto_field_set_bytes(hdr, fid, (uint8_t *)&val);
 241 }
 242
 243 uint8_t proto_field_get_u8(struct proto_hdr *hdr, uint32_t fid)
 244 {
 245         struct proto_field *field = proto_field_by_id(hdr, fid);
 246         uint8_t val = *__proto_field_get_bytes(field);
 247
 248         return field_unmask_and_unshift(field, val);
 249 }
 250
 251 void proto_field_set_u16(struct proto_hdr *hdr, uint32_t fid, uint16_t val)
 252 {
 253         proto_field_set_bytes(hdr, fid, (uint8_t *)&val);
 254 }
 255
 256 uint16_t proto_field_get_u16(struct proto_hdr *hdr, uint32_t fid)
 257 {
 258         struct proto_field *field = proto_field_by_id(hdr, fid);
 259         uint16_t val = *(uint16_t *)__proto_field_get_bytes(field);
 260
 261         return field_unmask_and_unshift(field, be16_to_cpu(val));
 262 }
 263
 264 void proto_field_set_u32(struct proto_hdr *hdr, uint32_t fid, uint32_t val)
 265 {
 266         proto_field_set_bytes(hdr, fid, (uint8_t *)&val);
 267 }
 268
 269 uint32_t proto_field_get_u32(struct proto_hdr *hdr, uint32_t fid)
 270 {
 271         struct proto_field *field = proto_field_by_id(hdr, fid);
 272         uint32_t val = *(uint32_t *)__proto_field_get_bytes(field);
 273
 274         return field_unmask_and_unshift(field, be32_to_cpu(val));
 275 }
 276
 277 void proto_field_set_default_bytes(struct proto_hdr *hdr, uint32_t fid, uint8_t *bytes)
 278 {
 279         __proto_field_set_bytes(hdr, fid, bytes, true, false);
 280 }
 281
 282 void proto_field_set_default_u8(struct proto_hdr *hdr, uint32_t fid, uint8_t val)
 283 {
 284         __proto_field_set_bytes(hdr, fid, (uint8_t *)&val, true, false);
 285 }
 286
 287 void proto_field_set_default_u16(struct proto_hdr *hdr, uint32_t fid, uint16_t val)
 288 {
 289         __proto_field_set_bytes(hdr, fid, (uint8_t *)&val, true, false);
 290 }
 291
 292 void proto_field_set_default_u32(struct proto_hdr *hdr, uint32_t fid, uint32_t val)
 293 {
 294         __proto_field_set_bytes(hdr, fid, (uint8_t *)&val, true, false);
 295 }
 296
 297 void proto_field_set_be16(struct proto_hdr *hdr, uint32_t fid, uint16_t val)
 298 {
 299         __proto_field_set_bytes(hdr, fid, (uint8_t *)&val, false, true);
 300 }
 301
 302 void proto_field_set_be32(struct proto_hdr *hdr, uint32_t fid, uint32_t val)
 303 {
 304         __proto_field_set_bytes(hdr, fid, (uint8_t *)&val, false, true);
 305 }
 306
 307 void proto_field_set_default_be16(struct proto_hdr *hdr, uint32_t fid, uint16_t val)
 308 {
 309         __proto_field_set_bytes(hdr, fid, (uint8_t *)&val, true, true);
 310 }
 311
 312 void proto_field_set_default_be32(struct proto_hdr *hdr, uint32_t fid, uint32_t val)
 313 {
 314         __proto_field_set_bytes(hdr, fid, (uint8_t *)&val, true, true);
 315 }
 316
 317 static void __proto_field_set_dev_mac(struct proto_hdr *hdr, uint32_t fid,
 318                                       bool is_default)
 319 {
 320         uint8_t mac[ETH_ALEN];
 321         int ret;
 322
 323         if (proto_field_is_set(hdr, fid))
 324                 return;
 325
 326         if (!hdr->ctx->dev)
 327                 panic("Device is not specified\n");
 328
 329         ret = device_hw_address(hdr->ctx->dev, mac, sizeof(mac));
 330         if (ret < 0)
 331                 panic("Could not get device hw address\n");
 332
 333         __proto_field_set_bytes(hdr, fid, mac, is_default, false);
 334 }
 335
 336 void proto_field_set_dev_mac(struct proto_hdr *hdr, uint32_t fid)
 337 {
 338         __proto_field_set_dev_mac(hdr, fid, false);
 339 }
 340
 341 void proto_field_set_default_dev_mac(struct proto_hdr *hdr, uint32_t fid)
 342 {
 343         __proto_field_set_dev_mac(hdr, fid, true);
 344 }
 345
 346 static void __proto_field_set_dev_ipv4(struct proto_hdr *hdr, uint32_t fid,
 347                                        bool is_default)
 348 {
 349         struct sockaddr_storage ss = { };
 350         struct sockaddr_in *ss4;
 351         int ret;
 352
 353         if (proto_field_is_set(hdr, fid))
 354                 return;
 355
 356         ret = device_address(hdr->ctx->dev, AF_INET, &ss);
 357         if (ret < 0)
 358                 panic("Could not get device IPv4 address\n");
 359
 360         ss4 = (struct sockaddr_in *) &ss;
 361         __proto_field_set_bytes(hdr, fid, (uint8_t *)&ss4->sin_addr.s_addr, is_default, false);
 362 }
 363
 364 void proto_field_set_dev_ipv4(struct proto_hdr *hdr, uint32_t fid)
 365 {
 366         __proto_field_set_dev_ipv4(hdr, fid, false);
 367 }
 368
 369 void proto_field_set_default_dev_ipv4(struct proto_hdr *hdr, uint32_t fid)
 370 {
 371         __proto_field_set_dev_ipv4(hdr, fid, true);
 372 }
 373
 374 static void __proto_field_set_dev_ipv6(struct proto_hdr *hdr, uint32_t fid,
 375                                        bool is_default)
 376 {
 377         struct sockaddr_storage ss = { };
 378         struct sockaddr_in6 *ss6;
 379         int ret;
 380
 381         if (proto_field_is_set(hdr, fid))
 382                 return;
 383
 384         ret = device_address(hdr->ctx->dev, AF_INET6, &ss);
 385         if (ret < 0)
 386                 panic("Could not get device IPv6 address\n");
 387
 388         ss6 = (struct sockaddr_in6 *) &ss;
 389         __proto_field_set_bytes(hdr, fid, (uint8_t *)&ss6->sin6_addr.s6_addr, is_default, false);
 390 }
 391
 392 void proto_field_set_dev_ipv6(struct proto_hdr *hdr, uint32_t fid)
 393 {
 394         __proto_field_set_dev_ipv6(hdr, fid, false);
 395 }
 396
 397 void proto_field_set_default_dev_ipv6(struct proto_hdr *hdr, uint32_t fid)
 398 {
 399         __proto_field_set_dev_ipv6(hdr, fid, true);
 400 }
 401
 402 void protos_init(const char *dev)
 403 {
 404         struct proto_hdr *p;
 405
 406         ctx.dev = dev;
 407
 408         protos_l2_init();
 409         protos_l3_init();
 410         protos_l4_init();
 411
 412         for (p = registered; p; p = p->next)
 413                 p->ctx = &ctx;
 414 }
 415
 416 void proto_packet_finish(void)
 417 {
 418         ssize_t i;
 419
 420         /* Go down from upper layers to do last calculations (checksum) */
 421         for (i = headers_count - 1; i >= 0; i--) {
 422                 struct proto_hdr *p = headers[i];
 423
 424                 if (p->packet_finish)
 425                         p->packet_finish(p);
 426         }
 427
 428         for (i = 0; i < headers_count; i++) {
 429                 struct proto_hdr *p = headers[i];
 430
 431                 if (p->fields) {
 432                         xfree(p->fields);
 433                         p->fields_count = 0;
 434                 }
 435
 436                 xfree(headers[i]);
 437         }
 438
 439         headers_count = 0;
 440 }