1 /* 2 * PPP IP Protocol Interface 3 * 4 * Written by Toshiharu OHNO (tony-o@iij.ad.jp) 5 * 6 * Copyright (C) 1993, Internet Initiative Japan, Inc. All rights reserverd. 7 * 8 * Redistribution and use in source and binary forms are permitted 9 * provided that the above copyright notice and this paragraph are 10 * duplicated in all such forms and that any documentation, 11 * advertising materials, and other materials related to such 12 * distribution and use acknowledge that the software was developed 13 * by the Internet Initiative Japan. The name of the 14 * IIJ may not be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 18 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 19 * 20 * $Id: ip.c,v 1.48 1998/06/27 23:48:45 brian Exp $ 21 * 22 * TODO: 23 * o Return ICMP message for filterd packet 24 * and optionaly record it into log. 25 */ 26 #include <sys/types.h> 27 #include <sys/socket.h> 28 #include <netinet/in.h> 29 #include <netinet/in_systm.h> 30 #include <netinet/ip.h> 31 #include <netinet/ip_icmp.h> 32 #include <netinet/udp.h> 33 #include <netinet/tcp.h> 34 #include <arpa/inet.h> 35 #include <sys/un.h> 36 37 #ifndef NOALIAS 38 #include <alias.h> 39 #endif 40 #include <errno.h> 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include <string.h> 44 #include <unistd.h> 45 46 #include "mbuf.h" 47 #include "log.h" 48 #include "defs.h" 49 #include "timer.h" 50 #include "fsm.h" 51 #include "lqr.h" 52 #include "hdlc.h" 53 #include "throughput.h" 54 #include "iplist.h" 55 #include "slcompress.h" 56 #include "ipcp.h" 57 #include "filter.h" 58 #include "descriptor.h" 59 #include "lcp.h" 60 #include "ccp.h" 61 #include "link.h" 62 #include "mp.h" 63 #include "bundle.h" 64 #include "vjcomp.h" 65 #include "tun.h" 66 #include "ip.h" 67 68 static const u_short interactive_ports[32] = { 69 544, 513, 514, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 70 0, 0, 0, 0, 0, 21, 22, 23, 0, 0, 0, 0, 0, 0, 0, 543, 71 }; 72 73 #define INTERACTIVE(p) (interactive_ports[(p) & 0x1F] == (p)) 74 75 static const char *TcpFlags[] = { "FIN", "SYN", "RST", "PSH", "ACK", "URG" }; 76 77 static int 78 PortMatch(int op, u_short pport, u_short rport) 79 { 80 switch (op) { 81 case OP_EQ: 82 return (pport == rport); 83 case OP_GT: 84 return (pport > rport); 85 case OP_LT: 86 return (pport < rport); 87 default: 88 return (0); 89 } 90 } 91 92 /* 93 * Check a packet against with defined filters 94 */ 95 static int 96 FilterCheck(struct ip *pip, struct filter *filter) 97 { 98 int gotinfo, cproto, estab, syn, finrst, n, len, didname; 99 struct tcphdr *th; 100 struct udphdr *uh; 101 struct icmp *ih; 102 char *ptop; 103 u_short sport, dport; 104 struct filterent *fp = filter->rule; 105 char dbuff[100]; 106 107 if (fp->action) { 108 cproto = gotinfo = estab = syn = finrst = didname = 0; 109 sport = dport = 0; 110 for (n = 0; n < MAXFILTERS; n++) { 111 if (fp->action) { 112 /* permit fragments on in and out filter */ 113 if (filter->fragok && (ntohs(pip->ip_off) & IP_OFFMASK) != 0) 114 return (A_PERMIT); 115 116 if (!didname) 117 log_Printf(LogDEBUG, "%s filter:\n", filter->name); 118 didname = 1; 119 120 if ((pip->ip_src.s_addr & fp->smask.s_addr) == 121 (fp->saddr.s_addr & fp->smask.s_addr) && 122 (pip->ip_dst.s_addr & fp->dmask.s_addr) == 123 (fp->daddr.s_addr & fp->dmask.s_addr)) { 124 if (fp->proto) { 125 if (!gotinfo) { 126 ptop = (char *) pip + (pip->ip_hl << 2); 127 128 switch (pip->ip_p) { 129 case IPPROTO_ICMP: 130 cproto = P_ICMP; 131 ih = (struct icmp *) ptop; 132 sport = ih->icmp_type; 133 estab = syn = finrst = -1; 134 if (log_IsKept(LogDEBUG)) 135 snprintf(dbuff, sizeof dbuff, "sport = %d", sport); 136 break; 137 case IPPROTO_UDP: 138 case IPPROTO_IGMP: 139 case IPPROTO_IPIP: 140 cproto = P_UDP; 141 uh = (struct udphdr *) ptop; 142 sport = ntohs(uh->uh_sport); 143 dport = ntohs(uh->uh_dport); 144 estab = syn = finrst = -1; 145 if (log_IsKept(LogDEBUG)) 146 snprintf(dbuff, sizeof dbuff, "sport = %d, dport = %d", 147 sport, dport); 148 break; 149 case IPPROTO_TCP: 150 cproto = P_TCP; 151 th = (struct tcphdr *) ptop; 152 sport = ntohs(th->th_sport); 153 dport = ntohs(th->th_dport); 154 estab = (th->th_flags & TH_ACK); 155 syn = (th->th_flags & TH_SYN); 156 finrst = (th->th_flags & (TH_FIN|TH_RST)); 157 if (log_IsKept(LogDEBUG) && !estab) 158 snprintf(dbuff, sizeof dbuff, 159 "flags = %02x, sport = %d, dport = %d", 160 th->th_flags, sport, dport); 161 break; 162 default: 163 return (A_DENY); /* We'll block unknown type of packet */ 164 } 165 if (log_IsKept(LogDEBUG)) { 166 if (estab != -1) { 167 len = strlen(dbuff); 168 snprintf(dbuff + len, sizeof dbuff - len, 169 ", estab = %d, syn = %d, finrst = %d", 170 estab, syn, finrst); 171 } 172 log_Printf(LogDEBUG, " Filter: proto = %s, %s\n", 173 filter_Proto2Nam(cproto), dbuff); 174 } 175 gotinfo = 1; 176 } 177 if (log_IsKept(LogDEBUG)) { 178 if (fp->opt.srcop != OP_NONE) { 179 snprintf(dbuff, sizeof dbuff, ", src %s %d", 180 filter_Op2Nam(fp->opt.srcop), fp->opt.srcport); 181 len = strlen(dbuff); 182 } else 183 len = 0; 184 if (fp->opt.dstop != OP_NONE) { 185 snprintf(dbuff + len, sizeof dbuff - len, 186 ", dst %s %d", filter_Op2Nam(fp->opt.dstop), 187 fp->opt.dstport); 188 } else if (!len) 189 *dbuff = '\0'; 190 191 log_Printf(LogDEBUG, " rule = %d: Address match, " 192 "check against proto %s%s, action = %s\n", 193 n, filter_Proto2Nam(fp->proto), 194 dbuff, filter_Action2Nam(fp->action)); 195 } 196 197 if (cproto == fp->proto) { 198 if ((fp->opt.srcop == OP_NONE || 199 PortMatch(fp->opt.srcop, sport, fp->opt.srcport)) && 200 (fp->opt.dstop == OP_NONE || 201 PortMatch(fp->opt.dstop, dport, fp->opt.dstport)) && 202 (fp->opt.estab == 0 || estab) && 203 (fp->opt.syn == 0 || syn) && 204 (fp->opt.finrst == 0 || finrst)) { 205 return (fp->action); 206 } 207 } 208 } else { 209 /* Address is mached. Make a decision. */ 210 log_Printf(LogDEBUG, " rule = %d: Address match, action = %s\n", n, 211 filter_Action2Nam(fp->action)); 212 return (fp->action); 213 } 214 } else 215 log_Printf(LogDEBUG, " rule = %d: Address mismatch\n", n); 216 } 217 fp++; 218 } 219 return (A_DENY); /* No rule is mached. Deny this packet */ 220 } 221 return (A_PERMIT); /* No rule is given. Permit this packet */ 222 } 223 224 #ifdef notdef 225 static void 226 IcmpError(struct ip * pip, int code) 227 { 228 struct mbuf *bp; 229 230 if (pip->ip_p != IPPROTO_ICMP) { 231 bp = mbuf_Alloc(cnt, MB_IPIN); 232 memcpy(MBUF_CTOP(bp), ptr, cnt); 233 vj_SendFrame(bp); 234 ipcp_AddOutOctets(cnt); 235 } 236 } 237 #endif 238 239 /* 240 * For debugging aid. 241 */ 242 int 243 PacketCheck(struct bundle *bundle, char *cp, int nb, struct filter *filter) 244 { 245 struct ip *pip; 246 struct tcphdr *th; 247 struct udphdr *uh; 248 struct icmp *icmph; 249 char *ptop; 250 int mask, len, n; 251 int pri = PRI_NORMAL; 252 int logit, loglen; 253 char logbuf[200]; 254 255 logit = log_IsKept(LogTCPIP) && filter->logok; 256 loglen = 0; 257 258 pip = (struct ip *) cp; 259 260 if (logit && loglen < sizeof logbuf) { 261 snprintf(logbuf + loglen, sizeof logbuf - loglen, "%s ", filter->name); 262 loglen += strlen(logbuf + loglen); 263 } 264 ptop = (cp + (pip->ip_hl << 2)); 265 266 switch (pip->ip_p) { 267 case IPPROTO_ICMP: 268 if (logit && loglen < sizeof logbuf) { 269 icmph = (struct icmp *) ptop; 270 snprintf(logbuf + loglen, sizeof logbuf - loglen, 271 "ICMP: %s:%d ---> ", inet_ntoa(pip->ip_src), icmph->icmp_type); 272 loglen += strlen(logbuf + loglen); 273 snprintf(logbuf + loglen, sizeof logbuf - loglen, 274 "%s:%d", inet_ntoa(pip->ip_dst), icmph->icmp_type); 275 loglen += strlen(logbuf + loglen); 276 } 277 break; 278 case IPPROTO_UDP: 279 if (logit && loglen < sizeof logbuf) { 280 uh = (struct udphdr *) ptop; 281 snprintf(logbuf + loglen, sizeof logbuf - loglen, 282 "UDP: %s:%d ---> ", inet_ntoa(pip->ip_src), ntohs(uh->uh_sport)); 283 loglen += strlen(logbuf + loglen); 284 snprintf(logbuf + loglen, sizeof logbuf - loglen, 285 "%s:%d", inet_ntoa(pip->ip_dst), ntohs(uh->uh_dport)); 286 loglen += strlen(logbuf + loglen); 287 } 288 break; 289 case IPPROTO_IPIP: 290 if (logit && loglen < sizeof logbuf) { 291 uh = (struct udphdr *) ptop; 292 snprintf(logbuf + loglen, sizeof logbuf - loglen, 293 "IPIP: %s:%d ---> ", inet_ntoa(pip->ip_src), ntohs(uh->uh_sport)); 294 loglen += strlen(logbuf + loglen); 295 snprintf(logbuf + loglen, sizeof logbuf - loglen, 296 "%s:%d", inet_ntoa(pip->ip_dst), ntohs(uh->uh_dport)); 297 loglen += strlen(logbuf + loglen); 298 } 299 break; 300 case IPPROTO_IGMP: 301 if (logit && loglen < sizeof logbuf) { 302 uh = (struct udphdr *) ptop; 303 snprintf(logbuf + loglen, sizeof logbuf - loglen, 304 "IGMP: %s:%d ---> ", inet_ntoa(pip->ip_src), ntohs(uh->uh_sport)); 305 loglen += strlen(logbuf + loglen); 306 snprintf(logbuf + loglen, sizeof logbuf - loglen, 307 "%s:%d", inet_ntoa(pip->ip_dst), ntohs(uh->uh_dport)); 308 loglen += strlen(logbuf + loglen); 309 } 310 break; 311 case IPPROTO_TCP: 312 th = (struct tcphdr *) ptop; 313 if (pip->ip_tos == IPTOS_LOWDELAY) 314 pri = PRI_FAST; 315 else if ((ntohs(pip->ip_off) & IP_OFFMASK) == 0) { 316 if (INTERACTIVE(ntohs(th->th_sport)) || INTERACTIVE(ntohs(th->th_dport))) 317 pri = PRI_FAST; 318 } 319 if (logit && loglen < sizeof logbuf) { 320 len = ntohs(pip->ip_len) - (pip->ip_hl << 2) - (th->th_off << 2); 321 snprintf(logbuf + loglen, sizeof logbuf - loglen, 322 "TCP: %s:%d ---> ", inet_ntoa(pip->ip_src), ntohs(th->th_sport)); 323 loglen += strlen(logbuf + loglen); 324 snprintf(logbuf + loglen, sizeof logbuf - loglen, 325 "%s:%d", inet_ntoa(pip->ip_dst), ntohs(th->th_dport)); 326 loglen += strlen(logbuf + loglen); 327 n = 0; 328 for (mask = TH_FIN; mask != 0x40; mask <<= 1) { 329 if (th->th_flags & mask) { 330 snprintf(logbuf + loglen, sizeof logbuf - loglen, " %s", TcpFlags[n]); 331 loglen += strlen(logbuf + loglen); 332 } 333 n++; 334 } 335 snprintf(logbuf + loglen, sizeof logbuf - loglen, 336 " seq:%lx ack:%lx (%d/%d)", 337 (u_long)ntohl(th->th_seq), (u_long)ntohl(th->th_ack), len, nb); 338 loglen += strlen(logbuf + loglen); 339 if ((th->th_flags & TH_SYN) && nb > 40) { 340 u_short *sp; 341 342 ptop += 20; 343 sp = (u_short *) ptop; 344 if (ntohs(sp[0]) == 0x0204) { 345 snprintf(logbuf + loglen, sizeof logbuf - loglen, 346 " MSS = %d", ntohs(sp[1])); 347 loglen += strlen(logbuf + loglen); 348 } 349 } 350 } 351 break; 352 } 353 354 if ((FilterCheck(pip, filter) & A_DENY)) { 355 if (logit) 356 log_Printf(LogTCPIP, "%s - BLOCKED\n", logbuf); 357 #ifdef notdef 358 if (direction == 0) 359 IcmpError(pip, pri); 360 #endif 361 return (-1); 362 } else { 363 /* Check Keep Alive filter */ 364 if (logit) { 365 if (FilterCheck(pip, &bundle->filter.alive) & A_DENY) 366 log_Printf(LogTCPIP, "%s - NO KEEPALIVE\n", logbuf); 367 else 368 log_Printf(LogTCPIP, "%s\n", logbuf); 369 } 370 return (pri); 371 } 372 } 373 374 void 375 ip_Input(struct bundle *bundle, struct mbuf * bp) 376 { 377 u_char *cp; 378 struct mbuf *wp; 379 int nb, nw; 380 struct tun_data tun; 381 struct ip *pip = (struct ip *)tun.data; 382 #ifndef NOALIAS 383 struct ip *piip = (struct ip *)((char *)pip + (pip->ip_hl << 2)); 384 #endif 385 386 tun_fill_header(tun, AF_INET); 387 cp = tun.data; 388 nb = 0; 389 for (wp = bp; wp; wp = wp->next) { /* Copy to contiguous region */ 390 if (sizeof tun.data - (cp - tun.data) < wp->cnt) { 391 log_Printf(LogWARN, "ip_Input: Packet too large (%d) - dropped\n", 392 mbuf_Length(bp)); 393 mbuf_Free(bp); 394 return; 395 } 396 memcpy(cp, MBUF_CTOP(wp), wp->cnt); 397 cp += wp->cnt; 398 nb += wp->cnt; 399 } 400 401 #ifndef NOALIAS 402 if (bundle->AliasEnabled && pip->ip_p != IPPROTO_IGMP && 403 (pip->ip_p != IPPROTO_IPIP || !IN_CLASSD(ntohl(piip->ip_dst.s_addr)))) { 404 struct tun_data *frag; 405 int iresult; 406 char *fptr; 407 408 iresult = PacketAliasIn(tun.data, sizeof tun.data); 409 nb = ntohs(((struct ip *) tun.data)->ip_len); 410 411 if (nb > MAX_MRU) { 412 log_Printf(LogWARN, "ip_Input: Problem with IP header length\n"); 413 mbuf_Free(bp); 414 return; 415 } 416 if (iresult == PKT_ALIAS_OK 417 || iresult == PKT_ALIAS_FOUND_HEADER_FRAGMENT) { 418 if (PacketCheck(bundle, tun.data, nb, &bundle->filter.in) < 0) { 419 mbuf_Free(bp); 420 return; 421 } 422 423 if (!(FilterCheck(pip, &bundle->filter.alive) & A_DENY)) 424 bundle_StartIdleTimer(bundle); 425 426 ipcp_AddInOctets(&bundle->ncp.ipcp, nb); 427 428 nb = ntohs(((struct ip *) tun.data)->ip_len); 429 nb += sizeof tun - sizeof tun.data; 430 nw = write(bundle->dev.fd, &tun, nb); 431 if (nw != nb) { 432 if (nw == -1) 433 log_Printf(LogERROR, "ip_Input: wrote %d, got %s\n", nb, 434 strerror(errno)); 435 else 436 log_Printf(LogERROR, "ip_Input: wrote %d, got %d\n", nb, nw); 437 } 438 439 if (iresult == PKT_ALIAS_FOUND_HEADER_FRAGMENT) { 440 while ((fptr = PacketAliasGetFragment(tun.data)) != NULL) { 441 PacketAliasFragmentIn(tun.data, fptr); 442 nb = ntohs(((struct ip *) fptr)->ip_len); 443 frag = (struct tun_data *) 444 ((char *)fptr - sizeof tun + sizeof tun.data); 445 nb += sizeof tun - sizeof tun.data; 446 nw = write(bundle->dev.fd, frag, nb); 447 if (nw != nb) { 448 if (nw == -1) 449 log_Printf(LogERROR, "ip_Input: wrote %d, got %s\n", nb, 450 strerror(errno)); 451 else 452 log_Printf(LogERROR, "ip_Input: wrote %d, got %d\n", nb, nw); 453 } 454 free(frag); 455 } 456 } 457 } else if (iresult == PKT_ALIAS_UNRESOLVED_FRAGMENT) { 458 nb = ntohs(((struct ip *) tun.data)->ip_len); 459 nb += sizeof tun - sizeof tun.data; 460 frag = (struct tun_data *)malloc(nb); 461 if (frag == NULL) 462 log_Printf(LogALERT, "ip_Input: Cannot allocate memory for fragment\n"); 463 else { 464 tun_fill_header(*frag, AF_INET); 465 memcpy(frag->data, tun.data, nb - sizeof tun + sizeof tun.data); 466 PacketAliasSaveFragment(frag->data); 467 } 468 } 469 } else 470 #endif /* #ifndef NOALIAS */ 471 { /* no aliasing */ 472 if (PacketCheck(bundle, tun.data, nb, &bundle->filter.in) < 0) { 473 mbuf_Free(bp); 474 return; 475 } 476 477 if (!(FilterCheck(pip, &bundle->filter.alive) & A_DENY)) 478 bundle_StartIdleTimer(bundle); 479 480 ipcp_AddInOctets(&bundle->ncp.ipcp, nb); 481 482 nb += sizeof tun - sizeof tun.data; 483 nw = write(bundle->dev.fd, &tun, nb); 484 if (nw != nb) { 485 if (nw == -1) 486 log_Printf(LogERROR, "ip_Input: wrote %d, got %s\n", nb, strerror(errno)); 487 else 488 log_Printf(LogERROR, "ip_Input: wrote %d, got %d\n", nb, nw); 489 } 490 } 491 mbuf_Free(bp); 492 } 493 494 static struct mqueue IpOutputQueues[PRI_FAST + 1]; 495 496 void 497 ip_Enqueue(int pri, char *ptr, int count) 498 { 499 struct mbuf *bp; 500 501 bp = mbuf_Alloc(count, MB_IPQ); 502 memcpy(MBUF_CTOP(bp), ptr, count); 503 mbuf_Enqueue(&IpOutputQueues[pri], bp); 504 } 505 506 int 507 ip_QueueLen() 508 { 509 struct mqueue *queue; 510 int result = 0; 511 512 for (queue = &IpOutputQueues[PRI_MAX]; queue >= IpOutputQueues; queue--) 513 result += queue->qlen; 514 515 return result; 516 } 517 518 int 519 ip_FlushPacket(struct link *l, struct bundle *bundle) 520 { 521 struct mqueue *queue; 522 struct mbuf *bp; 523 int cnt; 524 525 if (bundle->ncp.ipcp.fsm.state != ST_OPENED) 526 return 0; 527 528 for (queue = &IpOutputQueues[PRI_FAST]; queue >= IpOutputQueues; queue--) 529 if (queue->top) { 530 bp = mbuf_Dequeue(queue); 531 if (bp) { 532 struct ip *pip = (struct ip *)MBUF_CTOP(bp); 533 534 cnt = mbuf_Length(bp); 535 if (!(FilterCheck(pip, &bundle->filter.alive) & A_DENY)) 536 bundle_StartIdleTimer(bundle); 537 vj_SendFrame(l, bp, bundle); 538 ipcp_AddOutOctets(&bundle->ncp.ipcp, cnt); 539 return 1; 540 } 541 } 542 543 return 0; 544 } 545