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