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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 | /* * INET An implementation of the TCP/IP protocol suite for the LINUX * operating system. INET is implemented using the BSD Socket * interface as the means of communication with the user level. * * Generic frame diversion * * Version: @(#)eth.c 0.41 09/09/2000 * * Authors: * Benoit LOCHER: initial integration within the kernel with support for ethernet * Dave Miller: improvement on the code (correctness, performance and source files) * */ #include <linux/types.h> #include <linux/kernel.h> #include <linux/sched.h> #include <linux/string.h> #include <linux/mm.h> #include <linux/socket.h> #include <linux/in.h> #include <linux/inet.h> #include <linux/ip.h> #include <linux/udp.h> #include <linux/netdevice.h> #include <linux/etherdevice.h> #include <linux/skbuff.h> #include <linux/errno.h> #include <linux/init.h> #include <net/dst.h> #include <net/arp.h> #include <net/sock.h> #include <net/ipv6.h> #include <net/ip.h> #include <asm/uaccess.h> #include <asm/system.h> #include <asm/checksum.h> #include <linux/divert.h> #include <linux/sockios.h> const char sysctl_divert_version[32]="0.46"; /* Current version */ int __init dv_init(void) { printk(KERN_INFO "NET4: Frame Diverter %s\n", sysctl_divert_version); return 0; } /* * Allocate a divert_blk for a device. This must be an ethernet nic. */ int alloc_divert_blk(struct net_device *dev) { int alloc_size = (sizeof(struct divert_blk) + 3) & ~3; if (!strncmp(dev->name, "eth", 3)) { printk(KERN_DEBUG "divert: allocating divert_blk for %s\n", dev->name); dev->divert = (struct divert_blk *) kmalloc(alloc_size, GFP_KERNEL); if (dev->divert == NULL) { printk(KERN_DEBUG "divert: unable to allocate divert_blk for %s\n", dev->name); return -ENOMEM; } else { memset(dev->divert, 0, sizeof(struct divert_blk)); } dev_hold(dev); } else { printk(KERN_DEBUG "divert: not allocating divert_blk for non-ethernet device %s\n", dev->name); dev->divert = NULL; } return 0; } /* * Free a divert_blk allocated by the above function, if it was * allocated on that device. */ void free_divert_blk(struct net_device *dev) { if (dev->divert) { kfree(dev->divert); dev->divert=NULL; dev_put(dev); printk(KERN_DEBUG "divert: freeing divert_blk for %s\n", dev->name); } else { printk(KERN_DEBUG "divert: no divert_blk to free, %s not ethernet\n", dev->name); } } /* * Adds a tcp/udp (source or dest) port to an array */ int add_port(u16 ports[], u16 port) { int i; if (port == 0) return -EINVAL; /* Storing directly in network format for performance, * thanks Dave :) */ port = htons(port); for (i = 0; i < MAX_DIVERT_PORTS; i++) { if (ports[i] == port) return -EALREADY; } for (i = 0; i < MAX_DIVERT_PORTS; i++) { if (ports[i] == 0) { ports[i] = port; return 0; } } return -ENOBUFS; } /* * Removes a port from an array tcp/udp (source or dest) */ int remove_port(u16 ports[], u16 port) { int i; if (port == 0) return -EINVAL; /* Storing directly in network format for performance, * thanks Dave ! */ port = htons(port); for (i = 0; i < MAX_DIVERT_PORTS; i++) { if (ports[i] == port) { ports[i] = 0; return 0; } } return -EINVAL; } /* Some basic sanity checks on the arguments passed to divert_ioctl() */ int check_args(struct divert_cf *div_cf, struct net_device **dev) { char devname[32]; int ret; if (dev == NULL) return -EFAULT; /* GETVERSION: all other args are unused */ if (div_cf->cmd == DIVCMD_GETVERSION) return 0; /* Network device index should reasonably be between 0 and 1000 :) */ if (div_cf->dev_index < 0 || div_cf->dev_index > 1000) return -EINVAL; /* Let's try to find the ifname */ sprintf(devname, "eth%d", div_cf->dev_index); *dev = dev_get_by_name(devname); /* dev should NOT be null */ if (*dev == NULL) return -EINVAL; ret = 0; /* user issuing the ioctl must be a super one :) */ if (!capable(CAP_SYS_ADMIN)) { ret = -EPERM; goto out; } /* Device must have a divert_blk member NOT null */ if ((*dev)->divert == NULL) ret = -EINVAL; out: dev_put(*dev); return ret; } /* * control function of the diverter */ #define DVDBG(a) \ printk(KERN_DEBUG "divert_ioctl() line %d %s\n", __LINE__, (a)) int divert_ioctl(unsigned int cmd, struct divert_cf *arg) { struct divert_cf div_cf; struct divert_blk *div_blk; struct net_device *dev; int ret; switch (cmd) { case SIOCGIFDIVERT: DVDBG("SIOCGIFDIVERT, copy_from_user"); if (copy_from_user(&div_cf, arg, sizeof(struct divert_cf))) return -EFAULT; DVDBG("before check_args"); ret = check_args(&div_cf, &dev); if (ret) return ret; DVDBG("after checkargs"); div_blk = dev->divert; DVDBG("befre switch()"); switch (div_cf.cmd) { case DIVCMD_GETSTATUS: /* Now, just give the user the raw divert block * for him to play with :) */ if (copy_to_user(div_cf.arg1.ptr, dev->divert, sizeof(struct divert_blk))) return -EFAULT; break; case DIVCMD_GETVERSION: DVDBG("GETVERSION: checking ptr"); if (div_cf.arg1.ptr == NULL) return -EINVAL; DVDBG("GETVERSION: copying data to userland"); if (copy_to_user(div_cf.arg1.ptr, sysctl_divert_version, 32)) return -EFAULT; DVDBG("GETVERSION: data copied"); break; default: return -EINVAL; }; break; case SIOCSIFDIVERT: if (copy_from_user(&div_cf, arg, sizeof(struct divert_cf))) return -EFAULT; ret = check_args(&div_cf, &dev); if (ret) return ret; div_blk = dev->divert; switch(div_cf.cmd) { case DIVCMD_RESET: div_blk->divert = 0; div_blk->protos = DIVERT_PROTO_NONE; memset(div_blk->tcp_dst, 0, MAX_DIVERT_PORTS * sizeof(u16)); memset(div_blk->tcp_src, 0, MAX_DIVERT_PORTS * sizeof(u16)); memset(div_blk->udp_dst, 0, MAX_DIVERT_PORTS * sizeof(u16)); memset(div_blk->udp_src, 0, MAX_DIVERT_PORTS * sizeof(u16)); return 0; case DIVCMD_DIVERT: switch(div_cf.arg1.int32) { case DIVARG1_ENABLE: if (div_blk->divert) return -EALREADY; div_blk->divert = 1; break; case DIVARG1_DISABLE: if (!div_blk->divert) return -EALREADY; div_blk->divert = 0; break; default: return -EINVAL; }; break; case DIVCMD_IP: switch(div_cf.arg1.int32) { case DIVARG1_ENABLE: if (div_blk->protos & DIVERT_PROTO_IP) return -EALREADY; div_blk->protos |= DIVERT_PROTO_IP; break; case DIVARG1_DISABLE: if (!(div_blk->protos & DIVERT_PROTO_IP)) return -EALREADY; div_blk->protos &= ~DIVERT_PROTO_IP; break; default: return -EINVAL; }; break; case DIVCMD_TCP: switch(div_cf.arg1.int32) { case DIVARG1_ENABLE: if (div_blk->protos & DIVERT_PROTO_TCP) return -EALREADY; div_blk->protos |= DIVERT_PROTO_TCP; break; case DIVARG1_DISABLE: if (!(div_blk->protos & DIVERT_PROTO_TCP)) return -EALREADY; div_blk->protos &= ~DIVERT_PROTO_TCP; break; default: return -EINVAL; }; break; case DIVCMD_TCPDST: switch(div_cf.arg1.int32) { case DIVARG1_ADD: return add_port(div_blk->tcp_dst, div_cf.arg2.uint16); case DIVARG1_REMOVE: return remove_port(div_blk->tcp_dst, div_cf.arg2.uint16); default: return -EINVAL; }; break; case DIVCMD_TCPSRC: switch(div_cf.arg1.int32) { case DIVARG1_ADD: return add_port(div_blk->tcp_src, div_cf.arg2.uint16); case DIVARG1_REMOVE: return remove_port(div_blk->tcp_src, div_cf.arg2.uint16); default: return -EINVAL; }; break; case DIVCMD_UDP: switch(div_cf.arg1.int32) { case DIVARG1_ENABLE: if (div_blk->protos & DIVERT_PROTO_UDP) return -EALREADY; div_blk->protos |= DIVERT_PROTO_UDP; break; case DIVARG1_DISABLE: if (!(div_blk->protos & DIVERT_PROTO_UDP)) return -EALREADY; div_blk->protos &= ~DIVERT_PROTO_UDP; break; default: return -EINVAL; }; break; case DIVCMD_UDPDST: switch(div_cf.arg1.int32) { case DIVARG1_ADD: return add_port(div_blk->udp_dst, div_cf.arg2.uint16); case DIVARG1_REMOVE: return remove_port(div_blk->udp_dst, div_cf.arg2.uint16); default: return -EINVAL; }; break; case DIVCMD_UDPSRC: switch(div_cf.arg1.int32) { case DIVARG1_ADD: return add_port(div_blk->udp_src, div_cf.arg2.uint16); case DIVARG1_REMOVE: return remove_port(div_blk->udp_src, div_cf.arg2.uint16); default: return -EINVAL; }; break; case DIVCMD_ICMP: switch(div_cf.arg1.int32) { case DIVARG1_ENABLE: if (div_blk->protos & DIVERT_PROTO_ICMP) return -EALREADY; div_blk->protos |= DIVERT_PROTO_ICMP; break; case DIVARG1_DISABLE: if (!(div_blk->protos & DIVERT_PROTO_ICMP)) return -EALREADY; div_blk->protos &= ~DIVERT_PROTO_ICMP; break; default: return -EINVAL; }; break; default: return -EINVAL; }; break; default: return -EINVAL; }; return 0; } /* * Check if packet should have its dest mac address set to the box itself * for diversion */ #define ETH_DIVERT_FRAME(skb) \ memcpy(skb->mac.ethernet, skb->dev->dev_addr, ETH_ALEN); \ skb->pkt_type=PACKET_HOST void divert_frame(struct sk_buff *skb) { struct ethhdr *eth = skb->mac.ethernet; struct iphdr *iph; struct tcphdr *tcph; struct udphdr *udph; struct divert_blk *divert = skb->dev->divert; int i, src, dst; unsigned char *skb_data_end = skb->data + skb->len; /* Packet is already aimed at us, return */ if (!memcmp(eth, skb->dev->dev_addr, ETH_ALEN)) return; /* proto is not IP, do nothing */ if (eth->h_proto != htons(ETH_P_IP)) return; /* Divert all IP frames ? */ if (divert->protos & DIVERT_PROTO_IP) { ETH_DIVERT_FRAME(skb); return; } /* Check for possible (maliciously) malformed IP frame (thanks Dave) */ iph = (struct iphdr *) skb->data; if (((iph->ihl<<2)+(unsigned char*)(iph)) >= skb_data_end) { printk(KERN_INFO "divert: malformed IP packet !\n"); return; } switch (iph->protocol) { /* Divert all ICMP frames ? */ case IPPROTO_ICMP: if (divert->protos & DIVERT_PROTO_ICMP) { ETH_DIVERT_FRAME(skb); return; } break; /* Divert all TCP frames ? */ case IPPROTO_TCP: if (divert->protos & DIVERT_PROTO_TCP) { ETH_DIVERT_FRAME(skb); return; } /* Check for possible (maliciously) malformed IP * frame (thanx Dave) */ tcph = (struct tcphdr *) (((unsigned char *)iph) + (iph->ihl<<2)); if (((unsigned char *)(tcph+1)) >= skb_data_end) { printk(KERN_INFO "divert: malformed TCP packet !\n"); return; } /* Divert some tcp dst/src ports only ?*/ for (i = 0; i < MAX_DIVERT_PORTS; i++) { dst = divert->tcp_dst[i]; src = divert->tcp_src[i]; if ((dst && dst == tcph->dest) || (src && src == tcph->source)) { ETH_DIVERT_FRAME(skb); return; } } break; /* Divert all UDP frames ? */ case IPPROTO_UDP: if (divert->protos & DIVERT_PROTO_UDP) { ETH_DIVERT_FRAME(skb); return; } /* Check for possible (maliciously) malformed IP * packet (thanks Dave) */ udph = (struct udphdr *) (((unsigned char *)iph) + (iph->ihl<<2)); if (((unsigned char *)(udph+1)) >= skb_data_end) { printk(KERN_INFO "divert: malformed UDP packet !\n"); return; } /* Divert some udp dst/src ports only ? */ for (i = 0; i < MAX_DIVERT_PORTS; i++) { dst = divert->udp_dst[i]; src = divert->udp_src[i]; if ((dst && dst == udph->dest) || (src && src == udph->source)) { ETH_DIVERT_FRAME(skb); return; } } break; }; return; } |