1 /*- 2 * Copyright (c) 1982, 1986, 1988, 1990, 1993 3 * The Regents of the University of California. 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 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)ip_output.c 8.3 (Berkeley) 1/21/94 30 * $FreeBSD$ 31 */ 32 33 #include "opt_ipfw.h" 34 #include "opt_ipsec.h" 35 #include "opt_mac.h" 36 #include "opt_mbuf_stress_test.h" 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/kernel.h> 41 #include <sys/malloc.h> 42 #include <sys/mbuf.h> 43 #include <sys/priv.h> 44 #include <sys/protosw.h> 45 #include <sys/socket.h> 46 #include <sys/socketvar.h> 47 #include <sys/sysctl.h> 48 49 #include <net/if.h> 50 #include <net/netisr.h> 51 #include <net/pfil.h> 52 #include <net/route.h> 53 54 #include <netinet/in.h> 55 #include <netinet/in_systm.h> 56 #include <netinet/ip.h> 57 #include <netinet/in_pcb.h> 58 #include <netinet/in_var.h> 59 #include <netinet/ip_var.h> 60 #include <netinet/ip_options.h> 61 62 #ifdef IPSEC 63 #include <netinet/ip_ipsec.h> 64 #include <netipsec/ipsec.h> 65 #endif /* IPSEC*/ 66 67 #include <machine/in_cksum.h> 68 69 #include <security/mac/mac_framework.h> 70 71 #define print_ip(x, a, y) printf("%s %d.%d.%d.%d%s",\ 72 x, (ntohl(a.s_addr)>>24)&0xFF,\ 73 (ntohl(a.s_addr)>>16)&0xFF,\ 74 (ntohl(a.s_addr)>>8)&0xFF,\ 75 (ntohl(a.s_addr))&0xFF, y); 76 77 u_short ip_id; 78 79 #ifdef MBUF_STRESS_TEST 80 int mbuf_frag_size = 0; 81 SYSCTL_INT(_net_inet_ip, OID_AUTO, mbuf_frag_size, CTLFLAG_RW, 82 &mbuf_frag_size, 0, "Fragment outgoing mbufs to this size"); 83 #endif 84 85 static void ip_mloopback 86 (struct ifnet *, struct mbuf *, struct sockaddr_in *, int); 87 88 89 extern struct protosw inetsw[]; 90 91 /* 92 * IP output. The packet in mbuf chain m contains a skeletal IP 93 * header (with len, off, ttl, proto, tos, src, dst). 94 * The mbuf chain containing the packet will be freed. 95 * The mbuf opt, if present, will not be freed. 96 * In the IP forwarding case, the packet will arrive with options already 97 * inserted, so must have a NULL opt pointer. 98 */ 99 int 100 ip_output(struct mbuf *m, struct mbuf *opt, struct route *ro, int flags, 101 struct ip_moptions *imo, struct inpcb *inp) 102 { 103 struct ip *ip; 104 struct ifnet *ifp = NULL; /* keep compiler happy */ 105 struct mbuf *m0; 106 int hlen = sizeof (struct ip); 107 int mtu; 108 int len, error = 0; 109 struct sockaddr_in *dst = NULL; /* keep compiler happy */ 110 struct in_ifaddr *ia = NULL; 111 int isbroadcast, sw_csum; 112 struct route iproute; 113 struct in_addr odst; 114 #ifdef IPFIREWALL_FORWARD 115 struct m_tag *fwd_tag = NULL; 116 #endif 117 M_ASSERTPKTHDR(m); 118 119 if (ro == NULL) { 120 ro = &iproute; 121 bzero(ro, sizeof (*ro)); 122 } 123 124 if (inp != NULL) 125 INP_LOCK_ASSERT(inp); 126 127 if (opt) { 128 len = 0; 129 m = ip_insertoptions(m, opt, &len); 130 if (len != 0) 131 hlen = len; 132 } 133 ip = mtod(m, struct ip *); 134 135 /* 136 * Fill in IP header. If we are not allowing fragmentation, 137 * then the ip_id field is meaningless, but we don't set it 138 * to zero. Doing so causes various problems when devices along 139 * the path (routers, load balancers, firewalls, etc.) illegally 140 * disable DF on our packet. Note that a 16-bit counter 141 * will wrap around in less than 10 seconds at 100 Mbit/s on a 142 * medium with MTU 1500. See Steven M. Bellovin, "A Technique 143 * for Counting NATted Hosts", Proc. IMW'02, available at 144 * <http://www.cs.columbia.edu/~smb/papers/fnat.pdf>. 145 */ 146 if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) { 147 ip->ip_v = IPVERSION; 148 ip->ip_hl = hlen >> 2; 149 ip->ip_id = ip_newid(); 150 ipstat.ips_localout++; 151 } else { 152 hlen = ip->ip_hl << 2; 153 } 154 155 dst = (struct sockaddr_in *)&ro->ro_dst; 156 again: 157 /* 158 * If there is a cached route, 159 * check that it is to the same destination 160 * and is still up. If not, free it and try again. 161 * The address family should also be checked in case of sharing the 162 * cache with IPv6. 163 */ 164 if (ro->ro_rt && ((ro->ro_rt->rt_flags & RTF_UP) == 0 || 165 dst->sin_family != AF_INET || 166 dst->sin_addr.s_addr != ip->ip_dst.s_addr)) { 167 RTFREE(ro->ro_rt); 168 ro->ro_rt = (struct rtentry *)NULL; 169 } 170 #ifdef IPFIREWALL_FORWARD 171 if (ro->ro_rt == NULL && fwd_tag == NULL) { 172 #else 173 if (ro->ro_rt == NULL) { 174 #endif 175 bzero(dst, sizeof(*dst)); 176 dst->sin_family = AF_INET; 177 dst->sin_len = sizeof(*dst); 178 dst->sin_addr = ip->ip_dst; 179 } 180 /* 181 * If routing to interface only, short circuit routing lookup. 182 * The use of an all-ones broadcast address implies this; an 183 * interface is specified by the broadcast address of an interface, 184 * or the destination address of a ptp interface. 185 */ 186 if (flags & IP_SENDONES) { 187 if ((ia = ifatoia(ifa_ifwithbroadaddr(sintosa(dst)))) == NULL && 188 (ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL) { 189 ipstat.ips_noroute++; 190 error = ENETUNREACH; 191 goto bad; 192 } 193 ip->ip_dst.s_addr = INADDR_BROADCAST; 194 dst->sin_addr = ip->ip_dst; 195 ifp = ia->ia_ifp; 196 ip->ip_ttl = 1; 197 isbroadcast = 1; 198 } else if (flags & IP_ROUTETOIF) { 199 if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL && 200 (ia = ifatoia(ifa_ifwithnet(sintosa(dst)))) == NULL) { 201 ipstat.ips_noroute++; 202 error = ENETUNREACH; 203 goto bad; 204 } 205 ifp = ia->ia_ifp; 206 ip->ip_ttl = 1; 207 isbroadcast = in_broadcast(dst->sin_addr, ifp); 208 } else if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) && 209 imo != NULL && imo->imo_multicast_ifp != NULL) { 210 /* 211 * Bypass the normal routing lookup for multicast 212 * packets if the interface is specified. 213 */ 214 ifp = imo->imo_multicast_ifp; 215 IFP_TO_IA(ifp, ia); 216 isbroadcast = 0; /* fool gcc */ 217 } else { 218 /* 219 * We want to do any cloning requested by the link layer, 220 * as this is probably required in all cases for correct 221 * operation (as it is for ARP). 222 */ 223 if (ro->ro_rt == NULL) 224 rtalloc_ign(ro, 0); 225 if (ro->ro_rt == NULL) { 226 ipstat.ips_noroute++; 227 error = EHOSTUNREACH; 228 goto bad; 229 } 230 ia = ifatoia(ro->ro_rt->rt_ifa); 231 ifp = ro->ro_rt->rt_ifp; 232 ro->ro_rt->rt_rmx.rmx_pksent++; 233 if (ro->ro_rt->rt_flags & RTF_GATEWAY) 234 dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway; 235 if (ro->ro_rt->rt_flags & RTF_HOST) 236 isbroadcast = (ro->ro_rt->rt_flags & RTF_BROADCAST); 237 else 238 isbroadcast = in_broadcast(dst->sin_addr, ifp); 239 } 240 /* 241 * Calculate MTU. If we have a route that is up, use that, 242 * otherwise use the interface's MTU. 243 */ 244 if (ro->ro_rt != NULL && (ro->ro_rt->rt_flags & (RTF_UP|RTF_HOST))) { 245 /* 246 * This case can happen if the user changed the MTU 247 * of an interface after enabling IP on it. Because 248 * most netifs don't keep track of routes pointing to 249 * them, there is no way for one to update all its 250 * routes when the MTU is changed. 251 */ 252 if (ro->ro_rt->rt_rmx.rmx_mtu > ifp->if_mtu) 253 ro->ro_rt->rt_rmx.rmx_mtu = ifp->if_mtu; 254 mtu = ro->ro_rt->rt_rmx.rmx_mtu; 255 } else { 256 mtu = ifp->if_mtu; 257 } 258 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 259 struct in_multi *inm; 260 261 m->m_flags |= M_MCAST; 262 /* 263 * IP destination address is multicast. Make sure "dst" 264 * still points to the address in "ro". (It may have been 265 * changed to point to a gateway address, above.) 266 */ 267 dst = (struct sockaddr_in *)&ro->ro_dst; 268 /* 269 * See if the caller provided any multicast options 270 */ 271 if (imo != NULL) { 272 ip->ip_ttl = imo->imo_multicast_ttl; 273 if (imo->imo_multicast_vif != -1) 274 ip->ip_src.s_addr = 275 ip_mcast_src ? 276 ip_mcast_src(imo->imo_multicast_vif) : 277 INADDR_ANY; 278 } else 279 ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL; 280 /* 281 * Confirm that the outgoing interface supports multicast. 282 */ 283 if ((imo == NULL) || (imo->imo_multicast_vif == -1)) { 284 if ((ifp->if_flags & IFF_MULTICAST) == 0) { 285 ipstat.ips_noroute++; 286 error = ENETUNREACH; 287 goto bad; 288 } 289 } 290 /* 291 * If source address not specified yet, use address 292 * of outgoing interface. 293 */ 294 if (ip->ip_src.s_addr == INADDR_ANY) { 295 /* Interface may have no addresses. */ 296 if (ia != NULL) 297 ip->ip_src = IA_SIN(ia)->sin_addr; 298 } 299 300 IN_MULTI_LOCK(); 301 IN_LOOKUP_MULTI(ip->ip_dst, ifp, inm); 302 if (inm != NULL && 303 (imo == NULL || imo->imo_multicast_loop)) { 304 IN_MULTI_UNLOCK(); 305 /* 306 * If we belong to the destination multicast group 307 * on the outgoing interface, and the caller did not 308 * forbid loopback, loop back a copy. 309 */ 310 ip_mloopback(ifp, m, dst, hlen); 311 } 312 else { 313 IN_MULTI_UNLOCK(); 314 /* 315 * If we are acting as a multicast router, perform 316 * multicast forwarding as if the packet had just 317 * arrived on the interface to which we are about 318 * to send. The multicast forwarding function 319 * recursively calls this function, using the 320 * IP_FORWARDING flag to prevent infinite recursion. 321 * 322 * Multicasts that are looped back by ip_mloopback(), 323 * above, will be forwarded by the ip_input() routine, 324 * if necessary. 325 */ 326 if (ip_mrouter && (flags & IP_FORWARDING) == 0) { 327 /* 328 * If rsvp daemon is not running, do not 329 * set ip_moptions. This ensures that the packet 330 * is multicast and not just sent down one link 331 * as prescribed by rsvpd. 332 */ 333 if (!rsvp_on) 334 imo = NULL; 335 if (ip_mforward && 336 ip_mforward(ip, ifp, m, imo) != 0) { 337 m_freem(m); 338 goto done; 339 } 340 } 341 } 342 343 /* 344 * Multicasts with a time-to-live of zero may be looped- 345 * back, above, but must not be transmitted on a network. 346 * Also, multicasts addressed to the loopback interface 347 * are not sent -- the above call to ip_mloopback() will 348 * loop back a copy if this host actually belongs to the 349 * destination group on the loopback interface. 350 */ 351 if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) { 352 m_freem(m); 353 goto done; 354 } 355 356 goto sendit; 357 } 358 359 /* 360 * If the source address is not specified yet, use the address 361 * of the outoing interface. 362 */ 363 if (ip->ip_src.s_addr == INADDR_ANY) { 364 /* Interface may have no addresses. */ 365 if (ia != NULL) { 366 ip->ip_src = IA_SIN(ia)->sin_addr; 367 } 368 } 369 370 /* 371 * Verify that we have any chance at all of being able to queue the 372 * packet or packet fragments, unless ALTQ is enabled on the given 373 * interface in which case packetdrop should be done by queueing. 374 */ 375 #ifdef ALTQ 376 if ((!ALTQ_IS_ENABLED(&ifp->if_snd)) && 377 ((ifp->if_snd.ifq_len + ip->ip_len / mtu + 1) >= 378 ifp->if_snd.ifq_maxlen)) 379 #else 380 if ((ifp->if_snd.ifq_len + ip->ip_len / mtu + 1) >= 381 ifp->if_snd.ifq_maxlen) 382 #endif /* ALTQ */ 383 { 384 error = ENOBUFS; 385 ipstat.ips_odropped++; 386 ifp->if_snd.ifq_drops += (ip->ip_len / ifp->if_mtu + 1); 387 goto bad; 388 } 389 390 /* 391 * Look for broadcast address and 392 * verify user is allowed to send 393 * such a packet. 394 */ 395 if (isbroadcast) { 396 if ((ifp->if_flags & IFF_BROADCAST) == 0) { 397 error = EADDRNOTAVAIL; 398 goto bad; 399 } 400 if ((flags & IP_ALLOWBROADCAST) == 0) { 401 error = EACCES; 402 goto bad; 403 } 404 /* don't allow broadcast messages to be fragmented */ 405 if (ip->ip_len > mtu) { 406 error = EMSGSIZE; 407 goto bad; 408 } 409 m->m_flags |= M_BCAST; 410 } else { 411 m->m_flags &= ~M_BCAST; 412 } 413 414 sendit: 415 #ifdef IPSEC 416 switch(ip_ipsec_output(&m, inp, &flags, &error, &ro, &iproute, &dst, &ia, &ifp)) { 417 case 1: 418 goto bad; 419 case -1: 420 goto done; 421 case 0: 422 default: 423 break; /* Continue with packet processing. */ 424 } 425 /* Update variables that are affected by ipsec4_output(). */ 426 ip = mtod(m, struct ip *); 427 hlen = ip->ip_hl << 2; 428 #endif /* IPSEC */ 429 430 /* Jump over all PFIL processing if hooks are not active. */ 431 if (!PFIL_HOOKED(&inet_pfil_hook)) 432 goto passout; 433 434 /* Run through list of hooks for output packets. */ 435 odst.s_addr = ip->ip_dst.s_addr; 436 error = pfil_run_hooks(&inet_pfil_hook, &m, ifp, PFIL_OUT, inp); 437 if (error != 0 || m == NULL) 438 goto done; 439 440 ip = mtod(m, struct ip *); 441 442 /* See if destination IP address was changed by packet filter. */ 443 if (odst.s_addr != ip->ip_dst.s_addr) { 444 m->m_flags |= M_SKIP_FIREWALL; 445 /* If destination is now ourself drop to ip_input(). */ 446 if (in_localip(ip->ip_dst)) { 447 m->m_flags |= M_FASTFWD_OURS; 448 if (m->m_pkthdr.rcvif == NULL) 449 m->m_pkthdr.rcvif = loif; 450 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 451 m->m_pkthdr.csum_flags |= 452 CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 453 m->m_pkthdr.csum_data = 0xffff; 454 } 455 m->m_pkthdr.csum_flags |= 456 CSUM_IP_CHECKED | CSUM_IP_VALID; 457 458 error = netisr_queue(NETISR_IP, m); 459 goto done; 460 } else 461 goto again; /* Redo the routing table lookup. */ 462 } 463 464 #ifdef IPFIREWALL_FORWARD 465 /* See if local, if yes, send it to netisr with IP_FASTFWD_OURS. */ 466 if (m->m_flags & M_FASTFWD_OURS) { 467 if (m->m_pkthdr.rcvif == NULL) 468 m->m_pkthdr.rcvif = loif; 469 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 470 m->m_pkthdr.csum_flags |= 471 CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 472 m->m_pkthdr.csum_data = 0xffff; 473 } 474 m->m_pkthdr.csum_flags |= 475 CSUM_IP_CHECKED | CSUM_IP_VALID; 476 477 error = netisr_queue(NETISR_IP, m); 478 goto done; 479 } 480 /* Or forward to some other address? */ 481 fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 482 if (fwd_tag) { 483 dst = (struct sockaddr_in *)&ro->ro_dst; 484 bcopy((fwd_tag+1), dst, sizeof(struct sockaddr_in)); 485 m->m_flags |= M_SKIP_FIREWALL; 486 m_tag_delete(m, fwd_tag); 487 goto again; 488 } 489 #endif /* IPFIREWALL_FORWARD */ 490 491 passout: 492 /* 127/8 must not appear on wire - RFC1122. */ 493 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 494 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 495 if ((ifp->if_flags & IFF_LOOPBACK) == 0) { 496 ipstat.ips_badaddr++; 497 error = EADDRNOTAVAIL; 498 goto bad; 499 } 500 } 501 502 m->m_pkthdr.csum_flags |= CSUM_IP; 503 sw_csum = m->m_pkthdr.csum_flags & ~ifp->if_hwassist; 504 if (sw_csum & CSUM_DELAY_DATA) { 505 in_delayed_cksum(m); 506 sw_csum &= ~CSUM_DELAY_DATA; 507 } 508 m->m_pkthdr.csum_flags &= ifp->if_hwassist; 509 510 /* 511 * If small enough for interface, or the interface will take 512 * care of the fragmentation for us, we can just send directly. 513 */ 514 if (ip->ip_len <= mtu || 515 (m->m_pkthdr.csum_flags & ifp->if_hwassist & CSUM_TSO) != 0 || 516 ((ip->ip_off & IP_DF) == 0 && (ifp->if_hwassist & CSUM_FRAGMENT))) { 517 ip->ip_len = htons(ip->ip_len); 518 ip->ip_off = htons(ip->ip_off); 519 ip->ip_sum = 0; 520 if (sw_csum & CSUM_DELAY_IP) 521 ip->ip_sum = in_cksum(m, hlen); 522 523 /* 524 * Record statistics for this interface address. 525 * With CSUM_TSO the byte/packet count will be slightly 526 * incorrect because we count the IP+TCP headers only 527 * once instead of for every generated packet. 528 */ 529 if (!(flags & IP_FORWARDING) && ia) { 530 if (m->m_pkthdr.csum_flags & CSUM_TSO) 531 ia->ia_ifa.if_opackets += 532 m->m_pkthdr.len / m->m_pkthdr.tso_segsz; 533 else 534 ia->ia_ifa.if_opackets++; 535 ia->ia_ifa.if_obytes += m->m_pkthdr.len; 536 } 537 #ifdef MBUF_STRESS_TEST 538 if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size) 539 m = m_fragment(m, M_DONTWAIT, mbuf_frag_size); 540 #endif 541 /* 542 * Reset layer specific mbuf flags 543 * to avoid confusing lower layers. 544 */ 545 m->m_flags &= ~(M_PROTOFLAGS); 546 547 error = (*ifp->if_output)(ifp, m, 548 (struct sockaddr *)dst, ro->ro_rt); 549 goto done; 550 } 551 552 /* Balk when DF bit is set or the interface didn't support TSO. */ 553 if ((ip->ip_off & IP_DF) || (m->m_pkthdr.csum_flags & CSUM_TSO)) { 554 error = EMSGSIZE; 555 ipstat.ips_cantfrag++; 556 goto bad; 557 } 558 559 /* 560 * Too large for interface; fragment if possible. If successful, 561 * on return, m will point to a list of packets to be sent. 562 */ 563 error = ip_fragment(ip, &m, mtu, ifp->if_hwassist, sw_csum); 564 if (error) 565 goto bad; 566 for (; m; m = m0) { 567 m0 = m->m_nextpkt; 568 m->m_nextpkt = 0; 569 if (error == 0) { 570 /* Record statistics for this interface address. */ 571 if (ia != NULL) { 572 ia->ia_ifa.if_opackets++; 573 ia->ia_ifa.if_obytes += m->m_pkthdr.len; 574 } 575 /* 576 * Reset layer specific mbuf flags 577 * to avoid confusing upper layers. 578 */ 579 m->m_flags &= ~(M_PROTOFLAGS); 580 581 error = (*ifp->if_output)(ifp, m, 582 (struct sockaddr *)dst, ro->ro_rt); 583 } else 584 m_freem(m); 585 } 586 587 if (error == 0) 588 ipstat.ips_fragmented++; 589 590 done: 591 if (ro == &iproute && ro->ro_rt) { 592 RTFREE(ro->ro_rt); 593 } 594 return (error); 595 bad: 596 m_freem(m); 597 goto done; 598 } 599 600 /* 601 * Create a chain of fragments which fit the given mtu. m_frag points to the 602 * mbuf to be fragmented; on return it points to the chain with the fragments. 603 * Return 0 if no error. If error, m_frag may contain a partially built 604 * chain of fragments that should be freed by the caller. 605 * 606 * if_hwassist_flags is the hw offload capabilities (see if_data.ifi_hwassist) 607 * sw_csum contains the delayed checksums flags (e.g., CSUM_DELAY_IP). 608 */ 609 int 610 ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu, 611 u_long if_hwassist_flags, int sw_csum) 612 { 613 int error = 0; 614 int hlen = ip->ip_hl << 2; 615 int len = (mtu - hlen) & ~7; /* size of payload in each fragment */ 616 int off; 617 struct mbuf *m0 = *m_frag; /* the original packet */ 618 int firstlen; 619 struct mbuf **mnext; 620 int nfrags; 621 622 if (ip->ip_off & IP_DF) { /* Fragmentation not allowed */ 623 ipstat.ips_cantfrag++; 624 return EMSGSIZE; 625 } 626 627 /* 628 * Must be able to put at least 8 bytes per fragment. 629 */ 630 if (len < 8) 631 return EMSGSIZE; 632 633 /* 634 * If the interface will not calculate checksums on 635 * fragmented packets, then do it here. 636 */ 637 if (m0->m_pkthdr.csum_flags & CSUM_DELAY_DATA && 638 (if_hwassist_flags & CSUM_IP_FRAGS) == 0) { 639 in_delayed_cksum(m0); 640 m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 641 } 642 643 if (len > PAGE_SIZE) { 644 /* 645 * Fragment large datagrams such that each segment 646 * contains a multiple of PAGE_SIZE amount of data, 647 * plus headers. This enables a receiver to perform 648 * page-flipping zero-copy optimizations. 649 * 650 * XXX When does this help given that sender and receiver 651 * could have different page sizes, and also mtu could 652 * be less than the receiver's page size ? 653 */ 654 int newlen; 655 struct mbuf *m; 656 657 for (m = m0, off = 0; m && (off+m->m_len) <= mtu; m = m->m_next) 658 off += m->m_len; 659 660 /* 661 * firstlen (off - hlen) must be aligned on an 662 * 8-byte boundary 663 */ 664 if (off < hlen) 665 goto smart_frag_failure; 666 off = ((off - hlen) & ~7) + hlen; 667 newlen = (~PAGE_MASK) & mtu; 668 if ((newlen + sizeof (struct ip)) > mtu) { 669 /* we failed, go back the default */ 670 smart_frag_failure: 671 newlen = len; 672 off = hlen + len; 673 } 674 len = newlen; 675 676 } else { 677 off = hlen + len; 678 } 679 680 firstlen = off - hlen; 681 mnext = &m0->m_nextpkt; /* pointer to next packet */ 682 683 /* 684 * Loop through length of segment after first fragment, 685 * make new header and copy data of each part and link onto chain. 686 * Here, m0 is the original packet, m is the fragment being created. 687 * The fragments are linked off the m_nextpkt of the original 688 * packet, which after processing serves as the first fragment. 689 */ 690 for (nfrags = 1; off < ip->ip_len; off += len, nfrags++) { 691 struct ip *mhip; /* ip header on the fragment */ 692 struct mbuf *m; 693 int mhlen = sizeof (struct ip); 694 695 MGETHDR(m, M_DONTWAIT, MT_DATA); 696 if (m == NULL) { 697 error = ENOBUFS; 698 ipstat.ips_odropped++; 699 goto done; 700 } 701 m->m_flags |= (m0->m_flags & M_MCAST) | M_FRAG; 702 /* 703 * In the first mbuf, leave room for the link header, then 704 * copy the original IP header including options. The payload 705 * goes into an additional mbuf chain returned by m_copy(). 706 */ 707 m->m_data += max_linkhdr; 708 mhip = mtod(m, struct ip *); 709 *mhip = *ip; 710 if (hlen > sizeof (struct ip)) { 711 mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip); 712 mhip->ip_v = IPVERSION; 713 mhip->ip_hl = mhlen >> 2; 714 } 715 m->m_len = mhlen; 716 /* XXX do we need to add ip->ip_off below ? */ 717 mhip->ip_off = ((off - hlen) >> 3) + ip->ip_off; 718 if (off + len >= ip->ip_len) { /* last fragment */ 719 len = ip->ip_len - off; 720 m->m_flags |= M_LASTFRAG; 721 } else 722 mhip->ip_off |= IP_MF; 723 mhip->ip_len = htons((u_short)(len + mhlen)); 724 m->m_next = m_copy(m0, off, len); 725 if (m->m_next == NULL) { /* copy failed */ 726 m_free(m); 727 error = ENOBUFS; /* ??? */ 728 ipstat.ips_odropped++; 729 goto done; 730 } 731 m->m_pkthdr.len = mhlen + len; 732 m->m_pkthdr.rcvif = NULL; 733 #ifdef MAC 734 mac_create_fragment(m0, m); 735 #endif 736 m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags; 737 mhip->ip_off = htons(mhip->ip_off); 738 mhip->ip_sum = 0; 739 if (sw_csum & CSUM_DELAY_IP) 740 mhip->ip_sum = in_cksum(m, mhlen); 741 *mnext = m; 742 mnext = &m->m_nextpkt; 743 } 744 ipstat.ips_ofragments += nfrags; 745 746 /* set first marker for fragment chain */ 747 m0->m_flags |= M_FIRSTFRAG | M_FRAG; 748 m0->m_pkthdr.csum_data = nfrags; 749 750 /* 751 * Update first fragment by trimming what's been copied out 752 * and updating header. 753 */ 754 m_adj(m0, hlen + firstlen - ip->ip_len); 755 m0->m_pkthdr.len = hlen + firstlen; 756 ip->ip_len = htons((u_short)m0->m_pkthdr.len); 757 ip->ip_off |= IP_MF; 758 ip->ip_off = htons(ip->ip_off); 759 ip->ip_sum = 0; 760 if (sw_csum & CSUM_DELAY_IP) 761 ip->ip_sum = in_cksum(m0, hlen); 762 763 done: 764 *m_frag = m0; 765 return error; 766 } 767 768 void 769 in_delayed_cksum(struct mbuf *m) 770 { 771 struct ip *ip; 772 u_short csum, offset; 773 774 ip = mtod(m, struct ip *); 775 offset = ip->ip_hl << 2 ; 776 csum = in_cksum_skip(m, ip->ip_len, offset); 777 if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0) 778 csum = 0xffff; 779 offset += m->m_pkthdr.csum_data; /* checksum offset */ 780 781 if (offset + sizeof(u_short) > m->m_len) { 782 printf("delayed m_pullup, m->len: %d off: %d p: %d\n", 783 m->m_len, offset, ip->ip_p); 784 /* 785 * XXX 786 * this shouldn't happen, but if it does, the 787 * correct behavior may be to insert the checksum 788 * in the appropriate next mbuf in the chain. 789 */ 790 return; 791 } 792 *(u_short *)(m->m_data + offset) = csum; 793 } 794 795 /* 796 * IP socket option processing. 797 */ 798 int 799 ip_ctloutput(struct socket *so, struct sockopt *sopt) 800 { 801 struct inpcb *inp = sotoinpcb(so); 802 int error, optval; 803 804 error = optval = 0; 805 if (sopt->sopt_level != IPPROTO_IP) { 806 return (EINVAL); 807 } 808 809 switch (sopt->sopt_dir) { 810 case SOPT_SET: 811 switch (sopt->sopt_name) { 812 case IP_OPTIONS: 813 #ifdef notyet 814 case IP_RETOPTS: 815 #endif 816 { 817 struct mbuf *m; 818 if (sopt->sopt_valsize > MLEN) { 819 error = EMSGSIZE; 820 break; 821 } 822 MGET(m, sopt->sopt_td ? M_TRYWAIT : M_DONTWAIT, MT_DATA); 823 if (m == NULL) { 824 error = ENOBUFS; 825 break; 826 } 827 m->m_len = sopt->sopt_valsize; 828 error = sooptcopyin(sopt, mtod(m, char *), m->m_len, 829 m->m_len); 830 if (error) { 831 m_free(m); 832 break; 833 } 834 INP_LOCK(inp); 835 error = ip_pcbopts(inp, sopt->sopt_name, m); 836 INP_UNLOCK(inp); 837 return (error); 838 } 839 840 case IP_TOS: 841 case IP_TTL: 842 case IP_MINTTL: 843 case IP_RECVOPTS: 844 case IP_RECVRETOPTS: 845 case IP_RECVDSTADDR: 846 case IP_RECVTTL: 847 case IP_RECVIF: 848 case IP_FAITH: 849 case IP_ONESBCAST: 850 case IP_DONTFRAG: 851 error = sooptcopyin(sopt, &optval, sizeof optval, 852 sizeof optval); 853 if (error) 854 break; 855 856 switch (sopt->sopt_name) { 857 case IP_TOS: 858 inp->inp_ip_tos = optval; 859 break; 860 861 case IP_TTL: 862 inp->inp_ip_ttl = optval; 863 break; 864 865 case IP_MINTTL: 866 if (optval > 0 && optval <= MAXTTL) 867 inp->inp_ip_minttl = optval; 868 else 869 error = EINVAL; 870 break; 871 872 #define OPTSET(bit) do { \ 873 INP_LOCK(inp); \ 874 if (optval) \ 875 inp->inp_flags |= bit; \ 876 else \ 877 inp->inp_flags &= ~bit; \ 878 INP_UNLOCK(inp); \ 879 } while (0) 880 881 case IP_RECVOPTS: 882 OPTSET(INP_RECVOPTS); 883 break; 884 885 case IP_RECVRETOPTS: 886 OPTSET(INP_RECVRETOPTS); 887 break; 888 889 case IP_RECVDSTADDR: 890 OPTSET(INP_RECVDSTADDR); 891 break; 892 893 case IP_RECVTTL: 894 OPTSET(INP_RECVTTL); 895 break; 896 897 case IP_RECVIF: 898 OPTSET(INP_RECVIF); 899 break; 900 901 case IP_FAITH: 902 OPTSET(INP_FAITH); 903 break; 904 905 case IP_ONESBCAST: 906 OPTSET(INP_ONESBCAST); 907 break; 908 case IP_DONTFRAG: 909 OPTSET(INP_DONTFRAG); 910 break; 911 } 912 break; 913 #undef OPTSET 914 915 /* 916 * Multicast socket options are processed by the in_mcast 917 * module. 918 */ 919 case IP_MULTICAST_IF: 920 case IP_MULTICAST_VIF: 921 case IP_MULTICAST_TTL: 922 case IP_MULTICAST_LOOP: 923 case IP_ADD_MEMBERSHIP: 924 case IP_DROP_MEMBERSHIP: 925 case IP_ADD_SOURCE_MEMBERSHIP: 926 case IP_DROP_SOURCE_MEMBERSHIP: 927 case IP_BLOCK_SOURCE: 928 case IP_UNBLOCK_SOURCE: 929 case IP_MSFILTER: 930 case MCAST_JOIN_GROUP: 931 case MCAST_LEAVE_GROUP: 932 case MCAST_JOIN_SOURCE_GROUP: 933 case MCAST_LEAVE_SOURCE_GROUP: 934 case MCAST_BLOCK_SOURCE: 935 case MCAST_UNBLOCK_SOURCE: 936 error = inp_setmoptions(inp, sopt); 937 break; 938 939 case IP_PORTRANGE: 940 error = sooptcopyin(sopt, &optval, sizeof optval, 941 sizeof optval); 942 if (error) 943 break; 944 945 INP_LOCK(inp); 946 switch (optval) { 947 case IP_PORTRANGE_DEFAULT: 948 inp->inp_flags &= ~(INP_LOWPORT); 949 inp->inp_flags &= ~(INP_HIGHPORT); 950 break; 951 952 case IP_PORTRANGE_HIGH: 953 inp->inp_flags &= ~(INP_LOWPORT); 954 inp->inp_flags |= INP_HIGHPORT; 955 break; 956 957 case IP_PORTRANGE_LOW: 958 inp->inp_flags &= ~(INP_HIGHPORT); 959 inp->inp_flags |= INP_LOWPORT; 960 break; 961 962 default: 963 error = EINVAL; 964 break; 965 } 966 INP_UNLOCK(inp); 967 break; 968 969 #ifdef IPSEC 970 case IP_IPSEC_POLICY: 971 { 972 caddr_t req; 973 size_t len = 0; 974 int priv; 975 struct mbuf *m; 976 int optname; 977 978 if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */ 979 break; 980 if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */ 981 break; 982 if (sopt->sopt_td != NULL) { 983 /* 984 * XXXRW: Would be more desirable to do this 985 * one layer down so that we only exercise 986 * privilege if it is needed. 987 */ 988 error = priv_check(sopt->sopt_td, 989 PRIV_NETINET_IPSEC); 990 if (error) 991 priv = 0; 992 else 993 priv = 1; 994 } else 995 priv = 1; 996 req = mtod(m, caddr_t); 997 len = m->m_len; 998 optname = sopt->sopt_name; 999 error = ipsec4_set_policy(inp, optname, req, len, priv); 1000 m_freem(m); 1001 break; 1002 } 1003 #endif /* IPSEC */ 1004 1005 default: 1006 error = ENOPROTOOPT; 1007 break; 1008 } 1009 break; 1010 1011 case SOPT_GET: 1012 switch (sopt->sopt_name) { 1013 case IP_OPTIONS: 1014 case IP_RETOPTS: 1015 if (inp->inp_options) 1016 error = sooptcopyout(sopt, 1017 mtod(inp->inp_options, 1018 char *), 1019 inp->inp_options->m_len); 1020 else 1021 sopt->sopt_valsize = 0; 1022 break; 1023 1024 case IP_TOS: 1025 case IP_TTL: 1026 case IP_MINTTL: 1027 case IP_RECVOPTS: 1028 case IP_RECVRETOPTS: 1029 case IP_RECVDSTADDR: 1030 case IP_RECVTTL: 1031 case IP_RECVIF: 1032 case IP_PORTRANGE: 1033 case IP_FAITH: 1034 case IP_ONESBCAST: 1035 case IP_DONTFRAG: 1036 switch (sopt->sopt_name) { 1037 1038 case IP_TOS: 1039 optval = inp->inp_ip_tos; 1040 break; 1041 1042 case IP_TTL: 1043 optval = inp->inp_ip_ttl; 1044 break; 1045 1046 case IP_MINTTL: 1047 optval = inp->inp_ip_minttl; 1048 break; 1049 1050 #define OPTBIT(bit) (inp->inp_flags & bit ? 1 : 0) 1051 1052 case IP_RECVOPTS: 1053 optval = OPTBIT(INP_RECVOPTS); 1054 break; 1055 1056 case IP_RECVRETOPTS: 1057 optval = OPTBIT(INP_RECVRETOPTS); 1058 break; 1059 1060 case IP_RECVDSTADDR: 1061 optval = OPTBIT(INP_RECVDSTADDR); 1062 break; 1063 1064 case IP_RECVTTL: 1065 optval = OPTBIT(INP_RECVTTL); 1066 break; 1067 1068 case IP_RECVIF: 1069 optval = OPTBIT(INP_RECVIF); 1070 break; 1071 1072 case IP_PORTRANGE: 1073 if (inp->inp_flags & INP_HIGHPORT) 1074 optval = IP_PORTRANGE_HIGH; 1075 else if (inp->inp_flags & INP_LOWPORT) 1076 optval = IP_PORTRANGE_LOW; 1077 else 1078 optval = 0; 1079 break; 1080 1081 case IP_FAITH: 1082 optval = OPTBIT(INP_FAITH); 1083 break; 1084 1085 case IP_ONESBCAST: 1086 optval = OPTBIT(INP_ONESBCAST); 1087 break; 1088 case IP_DONTFRAG: 1089 optval = OPTBIT(INP_DONTFRAG); 1090 break; 1091 } 1092 error = sooptcopyout(sopt, &optval, sizeof optval); 1093 break; 1094 1095 /* 1096 * Multicast socket options are processed by the in_mcast 1097 * module. 1098 */ 1099 case IP_MULTICAST_IF: 1100 case IP_MULTICAST_VIF: 1101 case IP_MULTICAST_TTL: 1102 case IP_MULTICAST_LOOP: 1103 case IP_MSFILTER: 1104 error = inp_getmoptions(inp, sopt); 1105 break; 1106 1107 #ifdef IPSEC 1108 case IP_IPSEC_POLICY: 1109 { 1110 struct mbuf *m = NULL; 1111 caddr_t req = NULL; 1112 size_t len = 0; 1113 1114 if (m != 0) { 1115 req = mtod(m, caddr_t); 1116 len = m->m_len; 1117 } 1118 error = ipsec4_get_policy(sotoinpcb(so), req, len, &m); 1119 if (error == 0) 1120 error = soopt_mcopyout(sopt, m); /* XXX */ 1121 if (error == 0) 1122 m_freem(m); 1123 break; 1124 } 1125 #endif /* IPSEC */ 1126 1127 default: 1128 error = ENOPROTOOPT; 1129 break; 1130 } 1131 break; 1132 } 1133 return (error); 1134 } 1135 1136 /* 1137 * Routine called from ip_output() to loop back a copy of an IP multicast 1138 * packet to the input queue of a specified interface. Note that this 1139 * calls the output routine of the loopback "driver", but with an interface 1140 * pointer that might NOT be a loopback interface -- evil, but easier than 1141 * replicating that code here. 1142 */ 1143 static void 1144 ip_mloopback(struct ifnet *ifp, struct mbuf *m, struct sockaddr_in *dst, 1145 int hlen) 1146 { 1147 register struct ip *ip; 1148 struct mbuf *copym; 1149 1150 copym = m_copy(m, 0, M_COPYALL); 1151 if (copym != NULL && (copym->m_flags & M_EXT || copym->m_len < hlen)) 1152 copym = m_pullup(copym, hlen); 1153 if (copym != NULL) { 1154 /* If needed, compute the checksum and mark it as valid. */ 1155 if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 1156 in_delayed_cksum(copym); 1157 copym->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 1158 copym->m_pkthdr.csum_flags |= 1159 CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 1160 copym->m_pkthdr.csum_data = 0xffff; 1161 } 1162 /* 1163 * We don't bother to fragment if the IP length is greater 1164 * than the interface's MTU. Can this possibly matter? 1165 */ 1166 ip = mtod(copym, struct ip *); 1167 ip->ip_len = htons(ip->ip_len); 1168 ip->ip_off = htons(ip->ip_off); 1169 ip->ip_sum = 0; 1170 ip->ip_sum = in_cksum(copym, hlen); 1171 /* 1172 * NB: 1173 * It's not clear whether there are any lingering 1174 * reentrancy problems in other areas which might 1175 * be exposed by using ip_input directly (in 1176 * particular, everything which modifies the packet 1177 * in-place). Yet another option is using the 1178 * protosw directly to deliver the looped back 1179 * packet. For the moment, we'll err on the side 1180 * of safety by using if_simloop(). 1181 */ 1182 #if 1 /* XXX */ 1183 if (dst->sin_family != AF_INET) { 1184 printf("ip_mloopback: bad address family %d\n", 1185 dst->sin_family); 1186 dst->sin_family = AF_INET; 1187 } 1188 #endif 1189 1190 #ifdef notdef 1191 copym->m_pkthdr.rcvif = ifp; 1192 ip_input(copym); 1193 #else 1194 if_simloop(ifp, copym, dst->sin_family, 0); 1195 #endif 1196 } 1197 } 1198