1 /* 2 * Copyright (c) 1982, 1986, 1988, 1990 Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * from: @(#)ip_output.c 7.23 (Berkeley) 11/12/90 34 * $Id: ip_output.c,v 1.3 1993/05/22 11:42:35 cgd Exp $ 35 */ 36 37 #include "param.h" 38 #include "malloc.h" 39 #include "mbuf.h" 40 #include "errno.h" 41 #include "protosw.h" 42 #include "socket.h" 43 #include "socketvar.h" 44 45 #include "../net/if.h" 46 #include "../net/route.h" 47 48 #include "in.h" 49 #include "in_systm.h" 50 #include "ip.h" 51 #include "in_pcb.h" 52 #include "in_var.h" 53 #include "ip_var.h" 54 55 #ifdef vax 56 #include "machine/mtpr.h" 57 #endif 58 59 struct mbuf *ip_insertoptions(); 60 61 /* 62 * IP output. The packet in mbuf chain m contains a skeletal IP 63 * header (with len, off, ttl, proto, tos, src, dst). 64 * The mbuf chain containing the packet will be freed. 65 * The mbuf opt, if present, will not be freed. 66 */ 67 ip_output(m0, opt, ro, flags) 68 struct mbuf *m0; 69 struct mbuf *opt; 70 struct route *ro; 71 int flags; 72 { 73 register struct ip *ip, *mhip; 74 register struct ifnet *ifp; 75 register struct mbuf *m = m0; 76 register int hlen = sizeof (struct ip); 77 int len, off, error = 0; 78 struct route iproute; 79 struct sockaddr_in *dst; 80 struct in_ifaddr *ia; 81 82 #ifdef DIAGNOSTIC 83 if ((m->m_flags & M_PKTHDR) == 0) 84 panic("ip_output no HDR"); 85 #endif 86 if (opt) { 87 m = ip_insertoptions(m, opt, &len); 88 hlen = len; 89 } 90 ip = mtod(m, struct ip *); 91 /* 92 * Fill in IP header. 93 */ 94 if ((flags & IP_FORWARDING) == 0) { 95 ip->ip_v = IPVERSION; 96 ip->ip_off &= IP_DF; 97 ip->ip_id = htons(ip_id++); 98 ip->ip_hl = hlen >> 2; 99 } else { 100 hlen = ip->ip_hl << 2; 101 ipstat.ips_localout++; 102 } 103 /* 104 * Route packet. 105 */ 106 if (ro == 0) { 107 ro = &iproute; 108 bzero((caddr_t)ro, sizeof (*ro)); 109 } 110 dst = (struct sockaddr_in *)&ro->ro_dst; 111 /* 112 * If there is a cached route, 113 * check that it is to the same destination 114 * and is still up. If not, free it and try again. 115 */ 116 if (ro->ro_rt && ((ro->ro_rt->rt_flags & RTF_UP) == 0 || 117 dst->sin_addr.s_addr != ip->ip_dst.s_addr)) { 118 RTFREE(ro->ro_rt); 119 ro->ro_rt = (struct rtentry *)0; 120 } 121 if (ro->ro_rt == 0) { 122 dst->sin_family = AF_INET; 123 dst->sin_len = sizeof(*dst); 124 dst->sin_addr = ip->ip_dst; 125 } 126 /* 127 * If routing to interface only, 128 * short circuit routing lookup. 129 */ 130 if (flags & IP_ROUTETOIF) { 131 132 ia = (struct in_ifaddr *)ifa_ifwithdstaddr((struct sockaddr *)dst); 133 if (ia == 0) 134 ia = in_iaonnetof(in_netof(ip->ip_dst)); 135 if (ia == 0) { 136 error = ENETUNREACH; 137 goto bad; 138 } 139 ifp = ia->ia_ifp; 140 } else { 141 if (ro->ro_rt == 0) 142 rtalloc(ro); 143 if (ro->ro_rt == 0) { 144 error = EHOSTUNREACH; 145 goto bad; 146 } 147 ia = (struct in_ifaddr *)ro->ro_rt->rt_ifa; 148 ifp = ro->ro_rt->rt_ifp; 149 ro->ro_rt->rt_use++; 150 if (ro->ro_rt->rt_flags & RTF_GATEWAY) 151 dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway; 152 } 153 #ifndef notdef 154 /* 155 * If source address not specified yet, use address 156 * of outgoing interface. 157 */ 158 if (ip->ip_src.s_addr == INADDR_ANY) 159 ip->ip_src = IA_SIN(ia)->sin_addr; 160 #endif 161 /* 162 * Look for broadcast address and 163 * and verify user is allowed to send 164 * such a packet. 165 */ 166 if (in_broadcast(dst->sin_addr)) { 167 if ((ifp->if_flags & IFF_BROADCAST) == 0) { 168 error = EADDRNOTAVAIL; 169 goto bad; 170 } 171 if ((flags & IP_ALLOWBROADCAST) == 0) { 172 error = EACCES; 173 goto bad; 174 } 175 /* don't allow broadcast messages to be fragmented */ 176 if ((u_short)ip->ip_len > ifp->if_mtu) { 177 error = EMSGSIZE; 178 goto bad; 179 } 180 m->m_flags |= M_BCAST; 181 } 182 183 /* 184 * If small enough for interface, can just send directly. 185 */ 186 if ((u_short)ip->ip_len <= ifp->if_mtu) { 187 ip->ip_len = htons((u_short)ip->ip_len); 188 ip->ip_off = htons((u_short)ip->ip_off); 189 ip->ip_sum = 0; 190 ip->ip_sum = in_cksum(m, hlen); 191 error = (*ifp->if_output)(ifp, m, 192 (struct sockaddr *)dst, ro->ro_rt); 193 goto done; 194 } 195 ipstat.ips_fragmented++; 196 /* 197 * Too large for interface; fragment if possible. 198 * Must be able to put at least 8 bytes per fragment. 199 */ 200 if (ip->ip_off & IP_DF) { 201 error = EMSGSIZE; 202 goto bad; 203 } 204 len = (ifp->if_mtu - hlen) &~ 7; 205 if (len < 8) { 206 error = EMSGSIZE; 207 goto bad; 208 } 209 210 { 211 int mhlen, firstlen = len; 212 struct mbuf **mnext = &m->m_nextpkt; 213 214 /* 215 * Loop through length of segment after first fragment, 216 * make new header and copy data of each part and link onto chain. 217 */ 218 m0 = m; 219 mhlen = sizeof (struct ip); 220 for (off = hlen + len; off < (u_short)ip->ip_len; off += len) { 221 MGETHDR(m, M_DONTWAIT, MT_HEADER); 222 if (m == 0) { 223 error = ENOBUFS; 224 goto sendorfree; 225 } 226 m->m_data += max_linkhdr; 227 mhip = mtod(m, struct ip *); 228 *mhip = *ip; 229 if (hlen > sizeof (struct ip)) { 230 mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip); 231 mhip->ip_hl = mhlen >> 2; 232 } 233 m->m_len = mhlen; 234 mhip->ip_off = ((off - hlen) >> 3) + (ip->ip_off & ~IP_MF); 235 if (ip->ip_off & IP_MF) 236 mhip->ip_off |= IP_MF; 237 if (off + len >= (u_short)ip->ip_len) 238 len = (u_short)ip->ip_len - off; 239 else 240 mhip->ip_off |= IP_MF; 241 mhip->ip_len = htons((u_short)(len + mhlen)); 242 m->m_next = m_copy(m0, off, len); 243 if (m->m_next == 0) { 244 error = ENOBUFS; /* ??? */ 245 goto sendorfree; 246 } 247 m->m_pkthdr.len = mhlen + len; 248 m->m_pkthdr.rcvif = (struct ifnet *)0; 249 mhip->ip_off = htons((u_short)mhip->ip_off); 250 mhip->ip_sum = 0; 251 mhip->ip_sum = in_cksum(m, mhlen); 252 *mnext = m; 253 mnext = &m->m_nextpkt; 254 ipstat.ips_ofragments++; 255 } 256 /* 257 * Update first fragment by trimming what's been copied out 258 * and updating header, then send each fragment (in order). 259 */ 260 m = m0; 261 m_adj(m, hlen + firstlen - (u_short)ip->ip_len); 262 m->m_pkthdr.len = hlen + firstlen; 263 ip->ip_len = htons((u_short)m->m_pkthdr.len); 264 ip->ip_off = htons((u_short)(ip->ip_off | IP_MF)); 265 ip->ip_sum = 0; 266 ip->ip_sum = in_cksum(m, hlen); 267 sendorfree: 268 for (m = m0; m; m = m0) { 269 m0 = m->m_nextpkt; 270 m->m_nextpkt = 0; 271 if (error == 0) 272 error = (*ifp->if_output)(ifp, m, 273 (struct sockaddr *)dst, ro->ro_rt); 274 else 275 m_freem(m); 276 } 277 } 278 done: 279 if (ro == &iproute && (flags & IP_ROUTETOIF) == 0 && ro->ro_rt) 280 RTFREE(ro->ro_rt); 281 return (error); 282 bad: 283 m_freem(m0); 284 goto done; 285 } 286 287 /* 288 * Insert IP options into preformed packet. 289 * Adjust IP destination as required for IP source routing, 290 * as indicated by a non-zero in_addr at the start of the options. 291 */ 292 struct mbuf * 293 ip_insertoptions(m, opt, phlen) 294 register struct mbuf *m; 295 struct mbuf *opt; 296 int *phlen; 297 { 298 register struct ipoption *p = mtod(opt, struct ipoption *); 299 struct mbuf *n; 300 register struct ip *ip = mtod(m, struct ip *); 301 unsigned optlen; 302 303 optlen = opt->m_len - sizeof(p->ipopt_dst); 304 if (optlen + (u_short)ip->ip_len > IP_MAXPACKET) 305 return (m); /* XXX should fail */ 306 if (p->ipopt_dst.s_addr) 307 ip->ip_dst = p->ipopt_dst; 308 if (m->m_flags & M_EXT || m->m_data - optlen < m->m_pktdat) { 309 MGETHDR(n, M_DONTWAIT, MT_HEADER); 310 if (n == 0) 311 return (m); 312 n->m_pkthdr.len = m->m_pkthdr.len + optlen; 313 m->m_len -= sizeof(struct ip); 314 m->m_data += sizeof(struct ip); 315 n->m_next = m; 316 m = n; 317 m->m_len = optlen + sizeof(struct ip); 318 m->m_data += max_linkhdr; 319 bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 320 } else { 321 m->m_data -= optlen; 322 m->m_len += optlen; 323 m->m_pkthdr.len += optlen; 324 ovbcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip)); 325 } 326 ip = mtod(m, struct ip *); 327 bcopy((caddr_t)p->ipopt_list, (caddr_t)(ip + 1), (unsigned)optlen); 328 *phlen = sizeof(struct ip) + optlen; 329 ip->ip_len += optlen; 330 return (m); 331 } 332 333 /* 334 * Copy options from ip to jp, 335 * omitting those not copied during fragmentation. 336 */ 337 ip_optcopy(ip, jp) 338 struct ip *ip, *jp; 339 { 340 register u_char *cp, *dp; 341 int opt, optlen, cnt; 342 343 cp = (u_char *)(ip + 1); 344 dp = (u_char *)(jp + 1); 345 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 346 for (; cnt > 0; cnt -= optlen, cp += optlen) { 347 opt = cp[0]; 348 if (opt == IPOPT_EOL) 349 break; 350 if (opt == IPOPT_NOP) 351 optlen = 1; 352 else 353 optlen = cp[IPOPT_OLEN]; 354 /* bogus lengths should have been caught by ip_dooptions */ 355 if (optlen > cnt) 356 optlen = cnt; 357 if (IPOPT_COPIED(opt)) { 358 bcopy((caddr_t)cp, (caddr_t)dp, (unsigned)optlen); 359 dp += optlen; 360 } 361 } 362 for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++) 363 *dp++ = IPOPT_EOL; 364 return (optlen); 365 } 366 367 /* 368 * IP socket option processing. 369 */ 370 ip_ctloutput(op, so, level, optname, mp) 371 int op; 372 struct socket *so; 373 int level, optname; 374 struct mbuf **mp; 375 { 376 register struct inpcb *inp = sotoinpcb(so); 377 register struct mbuf *m = *mp; 378 register int optval; 379 int error = 0; 380 381 if (level != IPPROTO_IP) 382 error = EINVAL; 383 else switch (op) { 384 385 case PRCO_SETOPT: 386 switch (optname) { 387 case IP_OPTIONS: 388 #ifdef notyet 389 case IP_RETOPTS: 390 return (ip_pcbopts(optname, &inp->inp_options, m)); 391 #else 392 return (ip_pcbopts(&inp->inp_options, m)); 393 #endif 394 395 case IP_TOS: 396 case IP_TTL: 397 case IP_RECVOPTS: 398 case IP_RECVRETOPTS: 399 case IP_RECVDSTADDR: 400 if (m->m_len != sizeof(int)) 401 error = EINVAL; 402 else { 403 optval = *mtod(m, int *); 404 switch (optname) { 405 406 case IP_TOS: 407 inp->inp_ip.ip_tos = optval; 408 break; 409 410 case IP_TTL: 411 inp->inp_ip.ip_ttl = optval; 412 break; 413 #define OPTSET(bit) \ 414 if (optval) \ 415 inp->inp_flags |= bit; \ 416 else \ 417 inp->inp_flags &= ~bit; 418 419 case IP_RECVOPTS: 420 OPTSET(INP_RECVOPTS); 421 break; 422 423 case IP_RECVRETOPTS: 424 OPTSET(INP_RECVRETOPTS); 425 break; 426 427 case IP_RECVDSTADDR: 428 OPTSET(INP_RECVDSTADDR); 429 break; 430 } 431 } 432 break; 433 #undef OPTSET 434 435 default: 436 error = EINVAL; 437 break; 438 } 439 if (m) 440 (void)m_free(m); 441 break; 442 443 case PRCO_GETOPT: 444 switch (optname) { 445 case IP_OPTIONS: 446 case IP_RETOPTS: 447 *mp = m = m_get(M_WAIT, MT_SOOPTS); 448 if (inp->inp_options) { 449 m->m_len = inp->inp_options->m_len; 450 bcopy(mtod(inp->inp_options, caddr_t), 451 mtod(m, caddr_t), (unsigned)m->m_len); 452 } else 453 m->m_len = 0; 454 break; 455 456 case IP_TOS: 457 case IP_TTL: 458 case IP_RECVOPTS: 459 case IP_RECVRETOPTS: 460 case IP_RECVDSTADDR: 461 *mp = m = m_get(M_WAIT, MT_SOOPTS); 462 m->m_len = sizeof(int); 463 switch (optname) { 464 465 case IP_TOS: 466 optval = inp->inp_ip.ip_tos; 467 break; 468 469 case IP_TTL: 470 optval = inp->inp_ip.ip_ttl; 471 break; 472 473 #define OPTBIT(bit) (inp->inp_flags & bit ? 1 : 0) 474 475 case IP_RECVOPTS: 476 optval = OPTBIT(INP_RECVOPTS); 477 break; 478 479 case IP_RECVRETOPTS: 480 optval = OPTBIT(INP_RECVRETOPTS); 481 break; 482 483 case IP_RECVDSTADDR: 484 optval = OPTBIT(INP_RECVDSTADDR); 485 break; 486 } 487 *mtod(m, int *) = optval; 488 break; 489 490 default: 491 error = EINVAL; 492 break; 493 } 494 break; 495 } 496 return (error); 497 } 498 499 /* 500 * Set up IP options in pcb for insertion in output packets. 501 * Store in mbuf with pointer in pcbopt, adding pseudo-option 502 * with destination address if source routed. 503 */ 504 #ifdef notyet 505 ip_pcbopts(optname, pcbopt, m) 506 int optname; 507 #else 508 ip_pcbopts(pcbopt, m) 509 #endif 510 struct mbuf **pcbopt; 511 register struct mbuf *m; 512 { 513 register cnt, optlen; 514 register u_char *cp; 515 u_char opt; 516 517 /* turn off any old options */ 518 if (*pcbopt) 519 (void)m_free(*pcbopt); 520 *pcbopt = 0; 521 if (m == (struct mbuf *)0 || m->m_len == 0) { 522 /* 523 * Only turning off any previous options. 524 */ 525 if (m) 526 (void)m_free(m); 527 return (0); 528 } 529 530 #ifndef vax 531 if (m->m_len % sizeof(long)) 532 goto bad; 533 #endif 534 /* 535 * IP first-hop destination address will be stored before 536 * actual options; move other options back 537 * and clear it when none present. 538 */ 539 if (m->m_data + m->m_len + sizeof(struct in_addr) >= &m->m_dat[MLEN]) 540 goto bad; 541 cnt = m->m_len; 542 m->m_len += sizeof(struct in_addr); 543 cp = mtod(m, u_char *) + sizeof(struct in_addr); 544 ovbcopy(mtod(m, caddr_t), (caddr_t)cp, (unsigned)cnt); 545 bzero(mtod(m, caddr_t), sizeof(struct in_addr)); 546 547 for (; cnt > 0; cnt -= optlen, cp += optlen) { 548 opt = cp[IPOPT_OPTVAL]; 549 if (opt == IPOPT_EOL) 550 break; 551 if (opt == IPOPT_NOP) 552 optlen = 1; 553 else { 554 optlen = cp[IPOPT_OLEN]; 555 if (optlen <= IPOPT_OLEN || optlen > cnt) 556 goto bad; 557 } 558 switch (opt) { 559 560 default: 561 break; 562 563 case IPOPT_LSRR: 564 case IPOPT_SSRR: 565 /* 566 * user process specifies route as: 567 * ->A->B->C->D 568 * D must be our final destination (but we can't 569 * check that since we may not have connected yet). 570 * A is first hop destination, which doesn't appear in 571 * actual IP option, but is stored before the options. 572 */ 573 if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr)) 574 goto bad; 575 m->m_len -= sizeof(struct in_addr); 576 cnt -= sizeof(struct in_addr); 577 optlen -= sizeof(struct in_addr); 578 cp[IPOPT_OLEN] = optlen; 579 /* 580 * Move first hop before start of options. 581 */ 582 bcopy((caddr_t)&cp[IPOPT_OFFSET+1], mtod(m, caddr_t), 583 sizeof(struct in_addr)); 584 /* 585 * Then copy rest of options back 586 * to close up the deleted entry. 587 */ 588 ovbcopy((caddr_t)(&cp[IPOPT_OFFSET+1] + 589 sizeof(struct in_addr)), 590 (caddr_t)&cp[IPOPT_OFFSET+1], 591 (unsigned)cnt + sizeof(struct in_addr)); 592 break; 593 } 594 } 595 if (m->m_len > MAX_IPOPTLEN + sizeof(struct in_addr)) 596 goto bad; 597 *pcbopt = m; 598 return (0); 599 600 bad: 601 (void)m_free(m); 602 return (EINVAL); 603 } 604