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 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 34 35 #include "opt_ipfw.h" 36 #include "opt_ipsec.h" 37 #include "opt_mac.h" 38 #include "opt_mbuf_stress_test.h" 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/kernel.h> 43 #include <sys/malloc.h> 44 #include <sys/mbuf.h> 45 #include <sys/priv.h> 46 #include <sys/protosw.h> 47 #include <sys/socket.h> 48 #include <sys/socketvar.h> 49 #include <sys/sysctl.h> 50 51 #include <net/if.h> 52 #include <net/netisr.h> 53 #include <net/pfil.h> 54 #include <net/route.h> 55 56 #include <netinet/in.h> 57 #include <netinet/in_systm.h> 58 #include <netinet/ip.h> 59 #include <netinet/in_pcb.h> 60 #include <netinet/in_var.h> 61 #include <netinet/ip_var.h> 62 #include <netinet/ip_options.h> 63 64 #ifdef IPSEC 65 #include <netinet/ip_ipsec.h> 66 #include <netipsec/ipsec.h> 67 #endif /* IPSEC*/ 68 69 #include <machine/in_cksum.h> 70 71 #include <security/mac/mac_framework.h> 72 73 #define print_ip(x, a, y) printf("%s %d.%d.%d.%d%s",\ 74 x, (ntohl(a.s_addr)>>24)&0xFF,\ 75 (ntohl(a.s_addr)>>16)&0xFF,\ 76 (ntohl(a.s_addr)>>8)&0xFF,\ 77 (ntohl(a.s_addr))&0xFF, y); 78 79 u_short ip_id; 80 81 #ifdef MBUF_STRESS_TEST 82 int mbuf_frag_size = 0; 83 SYSCTL_INT(_net_inet_ip, OID_AUTO, mbuf_frag_size, CTLFLAG_RW, 84 &mbuf_frag_size, 0, "Fragment outgoing mbufs to this size"); 85 #endif 86 87 static void ip_mloopback 88 (struct ifnet *, struct mbuf *, struct sockaddr_in *, int); 89 90 91 extern struct protosw inetsw[]; 92 93 /* 94 * IP output. The packet in mbuf chain m contains a skeletal IP 95 * header (with len, off, ttl, proto, tos, src, dst). 96 * The mbuf chain containing the packet will be freed. 97 * The mbuf opt, if present, will not be freed. 98 * In the IP forwarding case, the packet will arrive with options already 99 * inserted, so must have a NULL opt pointer. 100 */ 101 int 102 ip_output(struct mbuf *m, struct mbuf *opt, struct route *ro, int flags, 103 struct ip_moptions *imo, struct inpcb *inp) 104 { 105 struct ip *ip; 106 struct ifnet *ifp = NULL; /* keep compiler happy */ 107 struct mbuf *m0; 108 int hlen = sizeof (struct ip); 109 int mtu; 110 int len, error = 0; 111 struct sockaddr_in *dst = NULL; /* keep compiler happy */ 112 struct in_ifaddr *ia = NULL; 113 int isbroadcast, sw_csum; 114 struct route iproute; 115 struct in_addr odst; 116 #ifdef IPFIREWALL_FORWARD 117 struct m_tag *fwd_tag = NULL; 118 #endif 119 M_ASSERTPKTHDR(m); 120 121 if (ro == NULL) { 122 ro = &iproute; 123 bzero(ro, sizeof (*ro)); 124 } 125 126 if (inp != NULL) 127 INP_LOCK_ASSERT(inp); 128 129 if (opt) { 130 len = 0; 131 m = ip_insertoptions(m, opt, &len); 132 if (len != 0) 133 hlen = len; 134 } 135 ip = mtod(m, struct ip *); 136 137 /* 138 * Fill in IP header. If we are not allowing fragmentation, 139 * then the ip_id field is meaningless, but we don't set it 140 * to zero. Doing so causes various problems when devices along 141 * the path (routers, load balancers, firewalls, etc.) illegally 142 * disable DF on our packet. Note that a 16-bit counter 143 * will wrap around in less than 10 seconds at 100 Mbit/s on a 144 * medium with MTU 1500. See Steven M. Bellovin, "A Technique 145 * for Counting NATted Hosts", Proc. IMW'02, available at 146 * <http://www.cs.columbia.edu/~smb/papers/fnat.pdf>. 147 */ 148 if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) { 149 ip->ip_v = IPVERSION; 150 ip->ip_hl = hlen >> 2; 151 ip->ip_id = ip_newid(); 152 ipstat.ips_localout++; 153 } else { 154 hlen = ip->ip_hl << 2; 155 } 156 157 dst = (struct sockaddr_in *)&ro->ro_dst; 158 again: 159 /* 160 * If there is a cached route, 161 * check that it is to the same destination 162 * and is still up. If not, free it and try again. 163 * The address family should also be checked in case of sharing the 164 * cache with IPv6. 165 */ 166 if (ro->ro_rt && ((ro->ro_rt->rt_flags & RTF_UP) == 0 || 167 dst->sin_family != AF_INET || 168 dst->sin_addr.s_addr != ip->ip_dst.s_addr)) { 169 RTFREE(ro->ro_rt); 170 ro->ro_rt = (struct rtentry *)NULL; 171 } 172 #ifdef IPFIREWALL_FORWARD 173 if (ro->ro_rt == NULL && fwd_tag == NULL) { 174 #else 175 if (ro->ro_rt == NULL) { 176 #endif 177 bzero(dst, sizeof(*dst)); 178 dst->sin_family = AF_INET; 179 dst->sin_len = sizeof(*dst); 180 dst->sin_addr = ip->ip_dst; 181 } 182 /* 183 * If routing to interface only, short circuit routing lookup. 184 * The use of an all-ones broadcast address implies this; an 185 * interface is specified by the broadcast address of an interface, 186 * or the destination address of a ptp interface. 187 */ 188 if (flags & IP_SENDONES) { 189 if ((ia = ifatoia(ifa_ifwithbroadaddr(sintosa(dst)))) == NULL && 190 (ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL) { 191 ipstat.ips_noroute++; 192 error = ENETUNREACH; 193 goto bad; 194 } 195 ip->ip_dst.s_addr = INADDR_BROADCAST; 196 dst->sin_addr = ip->ip_dst; 197 ifp = ia->ia_ifp; 198 ip->ip_ttl = 1; 199 isbroadcast = 1; 200 } else if (flags & IP_ROUTETOIF) { 201 if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL && 202 (ia = ifatoia(ifa_ifwithnet(sintosa(dst)))) == NULL) { 203 ipstat.ips_noroute++; 204 error = ENETUNREACH; 205 goto bad; 206 } 207 ifp = ia->ia_ifp; 208 ip->ip_ttl = 1; 209 isbroadcast = in_broadcast(dst->sin_addr, ifp); 210 } else if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) && 211 imo != NULL && imo->imo_multicast_ifp != NULL) { 212 /* 213 * Bypass the normal routing lookup for multicast 214 * packets if the interface is specified. 215 */ 216 ifp = imo->imo_multicast_ifp; 217 IFP_TO_IA(ifp, ia); 218 isbroadcast = 0; /* fool gcc */ 219 } else { 220 /* 221 * We want to do any cloning requested by the link layer, 222 * as this is probably required in all cases for correct 223 * operation (as it is for ARP). 224 */ 225 if (ro->ro_rt == NULL) 226 rtalloc_ign(ro, 0); 227 if (ro->ro_rt == NULL) { 228 ipstat.ips_noroute++; 229 error = EHOSTUNREACH; 230 goto bad; 231 } 232 ia = ifatoia(ro->ro_rt->rt_ifa); 233 ifp = ro->ro_rt->rt_ifp; 234 ro->ro_rt->rt_rmx.rmx_pksent++; 235 if (ro->ro_rt->rt_flags & RTF_GATEWAY) 236 dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway; 237 if (ro->ro_rt->rt_flags & RTF_HOST) 238 isbroadcast = (ro->ro_rt->rt_flags & RTF_BROADCAST); 239 else 240 isbroadcast = in_broadcast(dst->sin_addr, ifp); 241 } 242 /* 243 * Calculate MTU. If we have a route that is up, use that, 244 * otherwise use the interface's MTU. 245 */ 246 if (ro->ro_rt != NULL && (ro->ro_rt->rt_flags & (RTF_UP|RTF_HOST))) { 247 /* 248 * This case can happen if the user changed the MTU 249 * of an interface after enabling IP on it. Because 250 * most netifs don't keep track of routes pointing to 251 * them, there is no way for one to update all its 252 * routes when the MTU is changed. 253 */ 254 if (ro->ro_rt->rt_rmx.rmx_mtu > ifp->if_mtu) 255 ro->ro_rt->rt_rmx.rmx_mtu = ifp->if_mtu; 256 mtu = ro->ro_rt->rt_rmx.rmx_mtu; 257 } else { 258 mtu = ifp->if_mtu; 259 } 260 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 261 struct in_multi *inm; 262 263 m->m_flags |= M_MCAST; 264 /* 265 * IP destination address is multicast. Make sure "dst" 266 * still points to the address in "ro". (It may have been 267 * changed to point to a gateway address, above.) 268 */ 269 dst = (struct sockaddr_in *)&ro->ro_dst; 270 /* 271 * See if the caller provided any multicast options 272 */ 273 if (imo != NULL) { 274 ip->ip_ttl = imo->imo_multicast_ttl; 275 if (imo->imo_multicast_vif != -1) 276 ip->ip_src.s_addr = 277 ip_mcast_src ? 278 ip_mcast_src(imo->imo_multicast_vif) : 279 INADDR_ANY; 280 } else 281 ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL; 282 /* 283 * Confirm that the outgoing interface supports multicast. 284 */ 285 if ((imo == NULL) || (imo->imo_multicast_vif == -1)) { 286 if ((ifp->if_flags & IFF_MULTICAST) == 0) { 287 ipstat.ips_noroute++; 288 error = ENETUNREACH; 289 goto bad; 290 } 291 } 292 /* 293 * If source address not specified yet, use address 294 * of outgoing interface. 295 */ 296 if (ip->ip_src.s_addr == INADDR_ANY) { 297 /* Interface may have no addresses. */ 298 if (ia != NULL) 299 ip->ip_src = IA_SIN(ia)->sin_addr; 300 } 301 302 IN_MULTI_LOCK(); 303 IN_LOOKUP_MULTI(ip->ip_dst, ifp, inm); 304 if (inm != NULL && 305 (imo == NULL || imo->imo_multicast_loop)) { 306 IN_MULTI_UNLOCK(); 307 /* 308 * If we belong to the destination multicast group 309 * on the outgoing interface, and the caller did not 310 * forbid loopback, loop back a copy. 311 */ 312 ip_mloopback(ifp, m, dst, hlen); 313 } 314 else { 315 IN_MULTI_UNLOCK(); 316 /* 317 * If we are acting as a multicast router, perform 318 * multicast forwarding as if the packet had just 319 * arrived on the interface to which we are about 320 * to send. The multicast forwarding function 321 * recursively calls this function, using the 322 * IP_FORWARDING flag to prevent infinite recursion. 323 * 324 * Multicasts that are looped back by ip_mloopback(), 325 * above, will be forwarded by the ip_input() routine, 326 * if necessary. 327 */ 328 if (ip_mrouter && (flags & IP_FORWARDING) == 0) { 329 /* 330 * If rsvp daemon is not running, do not 331 * set ip_moptions. This ensures that the packet 332 * is multicast and not just sent down one link 333 * as prescribed by rsvpd. 334 */ 335 if (!rsvp_on) 336 imo = NULL; 337 if (ip_mforward && 338 ip_mforward(ip, ifp, m, imo) != 0) { 339 m_freem(m); 340 goto done; 341 } 342 } 343 } 344 345 /* 346 * Multicasts with a time-to-live of zero may be looped- 347 * back, above, but must not be transmitted on a network. 348 * Also, multicasts addressed to the loopback interface 349 * are not sent -- the above call to ip_mloopback() will 350 * loop back a copy if this host actually belongs to the 351 * destination group on the loopback interface. 352 */ 353 if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) { 354 m_freem(m); 355 goto done; 356 } 357 358 goto sendit; 359 } 360 361 /* 362 * If the source address is not specified yet, use the address 363 * of the outoing interface. 364 */ 365 if (ip->ip_src.s_addr == INADDR_ANY) { 366 /* Interface may have no addresses. */ 367 if (ia != NULL) { 368 ip->ip_src = IA_SIN(ia)->sin_addr; 369 } 370 } 371 372 /* 373 * Verify that we have any chance at all of being able to queue the 374 * packet or packet fragments, unless ALTQ is enabled on the given 375 * interface in which case packetdrop should be done by queueing. 376 */ 377 #ifdef ALTQ 378 if ((!ALTQ_IS_ENABLED(&ifp->if_snd)) && 379 ((ifp->if_snd.ifq_len + ip->ip_len / mtu + 1) >= 380 ifp->if_snd.ifq_maxlen)) 381 #else 382 if ((ifp->if_snd.ifq_len + ip->ip_len / mtu + 1) >= 383 ifp->if_snd.ifq_maxlen) 384 #endif /* ALTQ */ 385 { 386 error = ENOBUFS; 387 ipstat.ips_odropped++; 388 ifp->if_snd.ifq_drops += (ip->ip_len / ifp->if_mtu + 1); 389 goto bad; 390 } 391 392 /* 393 * Look for broadcast address and 394 * verify user is allowed to send 395 * such a packet. 396 */ 397 if (isbroadcast) { 398 if ((ifp->if_flags & IFF_BROADCAST) == 0) { 399 error = EADDRNOTAVAIL; 400 goto bad; 401 } 402 if ((flags & IP_ALLOWBROADCAST) == 0) { 403 error = EACCES; 404 goto bad; 405 } 406 /* don't allow broadcast messages to be fragmented */ 407 if (ip->ip_len > mtu) { 408 error = EMSGSIZE; 409 goto bad; 410 } 411 m->m_flags |= M_BCAST; 412 } else { 413 m->m_flags &= ~M_BCAST; 414 } 415 416 sendit: 417 #ifdef IPSEC 418 switch(ip_ipsec_output(&m, inp, &flags, &error, &ro, &iproute, &dst, &ia, &ifp)) { 419 case 1: 420 goto bad; 421 case -1: 422 goto done; 423 case 0: 424 default: 425 break; /* Continue with packet processing. */ 426 } 427 /* Update variables that are affected by ipsec4_output(). */ 428 ip = mtod(m, struct ip *); 429 hlen = ip->ip_hl << 2; 430 #endif /* IPSEC */ 431 432 /* Jump over all PFIL processing if hooks are not active. */ 433 if (!PFIL_HOOKED(&inet_pfil_hook)) 434 goto passout; 435 436 /* Run through list of hooks for output packets. */ 437 odst.s_addr = ip->ip_dst.s_addr; 438 error = pfil_run_hooks(&inet_pfil_hook, &m, ifp, PFIL_OUT, inp); 439 if (error != 0 || m == NULL) 440 goto done; 441 442 ip = mtod(m, struct ip *); 443 444 /* See if destination IP address was changed by packet filter. */ 445 if (odst.s_addr != ip->ip_dst.s_addr) { 446 m->m_flags |= M_SKIP_FIREWALL; 447 /* If destination is now ourself drop to ip_input(). */ 448 if (in_localip(ip->ip_dst)) { 449 m->m_flags |= M_FASTFWD_OURS; 450 if (m->m_pkthdr.rcvif == NULL) 451 m->m_pkthdr.rcvif = loif; 452 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 453 m->m_pkthdr.csum_flags |= 454 CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 455 m->m_pkthdr.csum_data = 0xffff; 456 } 457 m->m_pkthdr.csum_flags |= 458 CSUM_IP_CHECKED | CSUM_IP_VALID; 459 460 error = netisr_queue(NETISR_IP, m); 461 goto done; 462 } else 463 goto again; /* Redo the routing table lookup. */ 464 } 465 466 #ifdef IPFIREWALL_FORWARD 467 /* See if local, if yes, send it to netisr with IP_FASTFWD_OURS. */ 468 if (m->m_flags & M_FASTFWD_OURS) { 469 if (m->m_pkthdr.rcvif == NULL) 470 m->m_pkthdr.rcvif = loif; 471 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 472 m->m_pkthdr.csum_flags |= 473 CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 474 m->m_pkthdr.csum_data = 0xffff; 475 } 476 m->m_pkthdr.csum_flags |= 477 CSUM_IP_CHECKED | CSUM_IP_VALID; 478 479 error = netisr_queue(NETISR_IP, m); 480 goto done; 481 } 482 /* Or forward to some other address? */ 483 fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 484 if (fwd_tag) { 485 dst = (struct sockaddr_in *)&ro->ro_dst; 486 bcopy((fwd_tag+1), dst, sizeof(struct sockaddr_in)); 487 m->m_flags |= M_SKIP_FIREWALL; 488 m_tag_delete(m, fwd_tag); 489 goto again; 490 } 491 #endif /* IPFIREWALL_FORWARD */ 492 493 passout: 494 /* 127/8 must not appear on wire - RFC1122. */ 495 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 496 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 497 if ((ifp->if_flags & IFF_LOOPBACK) == 0) { 498 ipstat.ips_badaddr++; 499 error = EADDRNOTAVAIL; 500 goto bad; 501 } 502 } 503 504 m->m_pkthdr.csum_flags |= CSUM_IP; 505 sw_csum = m->m_pkthdr.csum_flags & ~ifp->if_hwassist; 506 if (sw_csum & CSUM_DELAY_DATA) { 507 in_delayed_cksum(m); 508 sw_csum &= ~CSUM_DELAY_DATA; 509 } 510 m->m_pkthdr.csum_flags &= ifp->if_hwassist; 511 512 /* 513 * If small enough for interface, or the interface will take 514 * care of the fragmentation for us, we can just send directly. 515 */ 516 if (ip->ip_len <= mtu || 517 (m->m_pkthdr.csum_flags & ifp->if_hwassist & CSUM_TSO) != 0 || 518 ((ip->ip_off & IP_DF) == 0 && (ifp->if_hwassist & CSUM_FRAGMENT))) { 519 ip->ip_len = htons(ip->ip_len); 520 ip->ip_off = htons(ip->ip_off); 521 ip->ip_sum = 0; 522 if (sw_csum & CSUM_DELAY_IP) 523 ip->ip_sum = in_cksum(m, hlen); 524 525 /* 526 * Record statistics for this interface address. 527 * With CSUM_TSO the byte/packet count will be slightly 528 * incorrect because we count the IP+TCP headers only 529 * once instead of for every generated packet. 530 */ 531 if (!(flags & IP_FORWARDING) && ia) { 532 if (m->m_pkthdr.csum_flags & CSUM_TSO) 533 ia->ia_ifa.if_opackets += 534 m->m_pkthdr.len / m->m_pkthdr.tso_segsz; 535 else 536 ia->ia_ifa.if_opackets++; 537 ia->ia_ifa.if_obytes += m->m_pkthdr.len; 538 } 539 #ifdef MBUF_STRESS_TEST 540 if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size) 541 m = m_fragment(m, M_DONTWAIT, mbuf_frag_size); 542 #endif 543 /* 544 * Reset layer specific mbuf flags 545 * to avoid confusing lower layers. 546 */ 547 m->m_flags &= ~(M_PROTOFLAGS); 548 549 error = (*ifp->if_output)(ifp, m, 550 (struct sockaddr *)dst, ro->ro_rt); 551 goto done; 552 } 553 554 /* Balk when DF bit is set or the interface didn't support TSO. */ 555 if ((ip->ip_off & IP_DF) || (m->m_pkthdr.csum_flags & CSUM_TSO)) { 556 error = EMSGSIZE; 557 ipstat.ips_cantfrag++; 558 goto bad; 559 } 560 561 /* 562 * Too large for interface; fragment if possible. If successful, 563 * on return, m will point to a list of packets to be sent. 564 */ 565 error = ip_fragment(ip, &m, mtu, ifp->if_hwassist, sw_csum); 566 if (error) 567 goto bad; 568 for (; m; m = m0) { 569 m0 = m->m_nextpkt; 570 m->m_nextpkt = 0; 571 if (error == 0) { 572 /* Record statistics for this interface address. */ 573 if (ia != NULL) { 574 ia->ia_ifa.if_opackets++; 575 ia->ia_ifa.if_obytes += m->m_pkthdr.len; 576 } 577 /* 578 * Reset layer specific mbuf flags 579 * to avoid confusing upper layers. 580 */ 581 m->m_flags &= ~(M_PROTOFLAGS); 582 583 error = (*ifp->if_output)(ifp, m, 584 (struct sockaddr *)dst, ro->ro_rt); 585 } else 586 m_freem(m); 587 } 588 589 if (error == 0) 590 ipstat.ips_fragmented++; 591 592 done: 593 if (ro == &iproute && ro->ro_rt) { 594 RTFREE(ro->ro_rt); 595 } 596 return (error); 597 bad: 598 m_freem(m); 599 goto done; 600 } 601 602 /* 603 * Create a chain of fragments which fit the given mtu. m_frag points to the 604 * mbuf to be fragmented; on return it points to the chain with the fragments. 605 * Return 0 if no error. If error, m_frag may contain a partially built 606 * chain of fragments that should be freed by the caller. 607 * 608 * if_hwassist_flags is the hw offload capabilities (see if_data.ifi_hwassist) 609 * sw_csum contains the delayed checksums flags (e.g., CSUM_DELAY_IP). 610 */ 611 int 612 ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu, 613 u_long if_hwassist_flags, int sw_csum) 614 { 615 int error = 0; 616 int hlen = ip->ip_hl << 2; 617 int len = (mtu - hlen) & ~7; /* size of payload in each fragment */ 618 int off; 619 struct mbuf *m0 = *m_frag; /* the original packet */ 620 int firstlen; 621 struct mbuf **mnext; 622 int nfrags; 623 624 if (ip->ip_off & IP_DF) { /* Fragmentation not allowed */ 625 ipstat.ips_cantfrag++; 626 return EMSGSIZE; 627 } 628 629 /* 630 * Must be able to put at least 8 bytes per fragment. 631 */ 632 if (len < 8) 633 return EMSGSIZE; 634 635 /* 636 * If the interface will not calculate checksums on 637 * fragmented packets, then do it here. 638 */ 639 if (m0->m_pkthdr.csum_flags & CSUM_DELAY_DATA && 640 (if_hwassist_flags & CSUM_IP_FRAGS) == 0) { 641 in_delayed_cksum(m0); 642 m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 643 } 644 645 if (len > PAGE_SIZE) { 646 /* 647 * Fragment large datagrams such that each segment 648 * contains a multiple of PAGE_SIZE amount of data, 649 * plus headers. This enables a receiver to perform 650 * page-flipping zero-copy optimizations. 651 * 652 * XXX When does this help given that sender and receiver 653 * could have different page sizes, and also mtu could 654 * be less than the receiver's page size ? 655 */ 656 int newlen; 657 struct mbuf *m; 658 659 for (m = m0, off = 0; m && (off+m->m_len) <= mtu; m = m->m_next) 660 off += m->m_len; 661 662 /* 663 * firstlen (off - hlen) must be aligned on an 664 * 8-byte boundary 665 */ 666 if (off < hlen) 667 goto smart_frag_failure; 668 off = ((off - hlen) & ~7) + hlen; 669 newlen = (~PAGE_MASK) & mtu; 670 if ((newlen + sizeof (struct ip)) > mtu) { 671 /* we failed, go back the default */ 672 smart_frag_failure: 673 newlen = len; 674 off = hlen + len; 675 } 676 len = newlen; 677 678 } else { 679 off = hlen + len; 680 } 681 682 firstlen = off - hlen; 683 mnext = &m0->m_nextpkt; /* pointer to next packet */ 684 685 /* 686 * Loop through length of segment after first fragment, 687 * make new header and copy data of each part and link onto chain. 688 * Here, m0 is the original packet, m is the fragment being created. 689 * The fragments are linked off the m_nextpkt of the original 690 * packet, which after processing serves as the first fragment. 691 */ 692 for (nfrags = 1; off < ip->ip_len; off += len, nfrags++) { 693 struct ip *mhip; /* ip header on the fragment */ 694 struct mbuf *m; 695 int mhlen = sizeof (struct ip); 696 697 MGETHDR(m, M_DONTWAIT, MT_DATA); 698 if (m == NULL) { 699 error = ENOBUFS; 700 ipstat.ips_odropped++; 701 goto done; 702 } 703 m->m_flags |= (m0->m_flags & M_MCAST) | M_FRAG; 704 /* 705 * In the first mbuf, leave room for the link header, then 706 * copy the original IP header including options. The payload 707 * goes into an additional mbuf chain returned by m_copy(). 708 */ 709 m->m_data += max_linkhdr; 710 mhip = mtod(m, struct ip *); 711 *mhip = *ip; 712 if (hlen > sizeof (struct ip)) { 713 mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip); 714 mhip->ip_v = IPVERSION; 715 mhip->ip_hl = mhlen >> 2; 716 } 717 m->m_len = mhlen; 718 /* XXX do we need to add ip->ip_off below ? */ 719 mhip->ip_off = ((off - hlen) >> 3) + ip->ip_off; 720 if (off + len >= ip->ip_len) { /* last fragment */ 721 len = ip->ip_len - off; 722 m->m_flags |= M_LASTFRAG; 723 } else 724 mhip->ip_off |= IP_MF; 725 mhip->ip_len = htons((u_short)(len + mhlen)); 726 m->m_next = m_copy(m0, off, len); 727 if (m->m_next == NULL) { /* copy failed */ 728 m_free(m); 729 error = ENOBUFS; /* ??? */ 730 ipstat.ips_odropped++; 731 goto done; 732 } 733 m->m_pkthdr.len = mhlen + len; 734 m->m_pkthdr.rcvif = NULL; 735 #ifdef MAC 736 mac_netinet_fragment(m0, m); 737 #endif 738 m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags; 739 mhip->ip_off = htons(mhip->ip_off); 740 mhip->ip_sum = 0; 741 if (sw_csum & CSUM_DELAY_IP) 742 mhip->ip_sum = in_cksum(m, mhlen); 743 *mnext = m; 744 mnext = &m->m_nextpkt; 745 } 746 ipstat.ips_ofragments += nfrags; 747 748 /* set first marker for fragment chain */ 749 m0->m_flags |= M_FIRSTFRAG | M_FRAG; 750 m0->m_pkthdr.csum_data = nfrags; 751 752 /* 753 * Update first fragment by trimming what's been copied out 754 * and updating header. 755 */ 756 m_adj(m0, hlen + firstlen - ip->ip_len); 757 m0->m_pkthdr.len = hlen + firstlen; 758 ip->ip_len = htons((u_short)m0->m_pkthdr.len); 759 ip->ip_off |= IP_MF; 760 ip->ip_off = htons(ip->ip_off); 761 ip->ip_sum = 0; 762 if (sw_csum & CSUM_DELAY_IP) 763 ip->ip_sum = in_cksum(m0, hlen); 764 765 done: 766 *m_frag = m0; 767 return error; 768 } 769 770 void 771 in_delayed_cksum(struct mbuf *m) 772 { 773 struct ip *ip; 774 u_short csum, offset; 775 776 ip = mtod(m, struct ip *); 777 offset = ip->ip_hl << 2 ; 778 csum = in_cksum_skip(m, ip->ip_len, offset); 779 if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0) 780 csum = 0xffff; 781 offset += m->m_pkthdr.csum_data; /* checksum offset */ 782 783 if (offset + sizeof(u_short) > m->m_len) { 784 printf("delayed m_pullup, m->len: %d off: %d p: %d\n", 785 m->m_len, offset, ip->ip_p); 786 /* 787 * XXX 788 * this shouldn't happen, but if it does, the 789 * correct behavior may be to insert the checksum 790 * in the appropriate next mbuf in the chain. 791 */ 792 return; 793 } 794 *(u_short *)(m->m_data + offset) = csum; 795 } 796 797 /* 798 * IP socket option processing. 799 */ 800 int 801 ip_ctloutput(struct socket *so, struct sockopt *sopt) 802 { 803 struct inpcb *inp = sotoinpcb(so); 804 int error, optval; 805 806 error = optval = 0; 807 if (sopt->sopt_level != IPPROTO_IP) { 808 return (EINVAL); 809 } 810 811 switch (sopt->sopt_dir) { 812 case SOPT_SET: 813 switch (sopt->sopt_name) { 814 case IP_OPTIONS: 815 #ifdef notyet 816 case IP_RETOPTS: 817 #endif 818 { 819 struct mbuf *m; 820 if (sopt->sopt_valsize > MLEN) { 821 error = EMSGSIZE; 822 break; 823 } 824 MGET(m, sopt->sopt_td ? M_TRYWAIT : M_DONTWAIT, MT_DATA); 825 if (m == NULL) { 826 error = ENOBUFS; 827 break; 828 } 829 m->m_len = sopt->sopt_valsize; 830 error = sooptcopyin(sopt, mtod(m, char *), m->m_len, 831 m->m_len); 832 if (error) { 833 m_free(m); 834 break; 835 } 836 INP_LOCK(inp); 837 error = ip_pcbopts(inp, sopt->sopt_name, m); 838 INP_UNLOCK(inp); 839 return (error); 840 } 841 842 case IP_TOS: 843 case IP_TTL: 844 case IP_MINTTL: 845 case IP_RECVOPTS: 846 case IP_RECVRETOPTS: 847 case IP_RECVDSTADDR: 848 case IP_RECVTTL: 849 case IP_RECVIF: 850 case IP_FAITH: 851 case IP_ONESBCAST: 852 case IP_DONTFRAG: 853 error = sooptcopyin(sopt, &optval, sizeof optval, 854 sizeof optval); 855 if (error) 856 break; 857 858 switch (sopt->sopt_name) { 859 case IP_TOS: 860 inp->inp_ip_tos = optval; 861 break; 862 863 case IP_TTL: 864 inp->inp_ip_ttl = optval; 865 break; 866 867 case IP_MINTTL: 868 if (optval > 0 && optval <= MAXTTL) 869 inp->inp_ip_minttl = optval; 870 else 871 error = EINVAL; 872 break; 873 874 #define OPTSET(bit) do { \ 875 INP_LOCK(inp); \ 876 if (optval) \ 877 inp->inp_flags |= bit; \ 878 else \ 879 inp->inp_flags &= ~bit; \ 880 INP_UNLOCK(inp); \ 881 } while (0) 882 883 case IP_RECVOPTS: 884 OPTSET(INP_RECVOPTS); 885 break; 886 887 case IP_RECVRETOPTS: 888 OPTSET(INP_RECVRETOPTS); 889 break; 890 891 case IP_RECVDSTADDR: 892 OPTSET(INP_RECVDSTADDR); 893 break; 894 895 case IP_RECVTTL: 896 OPTSET(INP_RECVTTL); 897 break; 898 899 case IP_RECVIF: 900 OPTSET(INP_RECVIF); 901 break; 902 903 case IP_FAITH: 904 OPTSET(INP_FAITH); 905 break; 906 907 case IP_ONESBCAST: 908 OPTSET(INP_ONESBCAST); 909 break; 910 case IP_DONTFRAG: 911 OPTSET(INP_DONTFRAG); 912 break; 913 } 914 break; 915 #undef OPTSET 916 917 /* 918 * Multicast socket options are processed by the in_mcast 919 * module. 920 */ 921 case IP_MULTICAST_IF: 922 case IP_MULTICAST_VIF: 923 case IP_MULTICAST_TTL: 924 case IP_MULTICAST_LOOP: 925 case IP_ADD_MEMBERSHIP: 926 case IP_DROP_MEMBERSHIP: 927 case IP_ADD_SOURCE_MEMBERSHIP: 928 case IP_DROP_SOURCE_MEMBERSHIP: 929 case IP_BLOCK_SOURCE: 930 case IP_UNBLOCK_SOURCE: 931 case IP_MSFILTER: 932 case MCAST_JOIN_GROUP: 933 case MCAST_LEAVE_GROUP: 934 case MCAST_JOIN_SOURCE_GROUP: 935 case MCAST_LEAVE_SOURCE_GROUP: 936 case MCAST_BLOCK_SOURCE: 937 case MCAST_UNBLOCK_SOURCE: 938 error = inp_setmoptions(inp, sopt); 939 break; 940 941 case IP_PORTRANGE: 942 error = sooptcopyin(sopt, &optval, sizeof optval, 943 sizeof optval); 944 if (error) 945 break; 946 947 INP_LOCK(inp); 948 switch (optval) { 949 case IP_PORTRANGE_DEFAULT: 950 inp->inp_flags &= ~(INP_LOWPORT); 951 inp->inp_flags &= ~(INP_HIGHPORT); 952 break; 953 954 case IP_PORTRANGE_HIGH: 955 inp->inp_flags &= ~(INP_LOWPORT); 956 inp->inp_flags |= INP_HIGHPORT; 957 break; 958 959 case IP_PORTRANGE_LOW: 960 inp->inp_flags &= ~(INP_HIGHPORT); 961 inp->inp_flags |= INP_LOWPORT; 962 break; 963 964 default: 965 error = EINVAL; 966 break; 967 } 968 INP_UNLOCK(inp); 969 break; 970 971 #ifdef IPSEC 972 case IP_IPSEC_POLICY: 973 { 974 caddr_t req; 975 size_t len = 0; 976 int priv; 977 struct mbuf *m; 978 int optname; 979 980 if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */ 981 break; 982 if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */ 983 break; 984 if (sopt->sopt_td != NULL) { 985 /* 986 * XXXRW: Would be more desirable to do this 987 * one layer down so that we only exercise 988 * privilege if it is needed. 989 */ 990 error = priv_check(sopt->sopt_td, 991 PRIV_NETINET_IPSEC); 992 if (error) 993 priv = 0; 994 else 995 priv = 1; 996 } else 997 priv = 1; 998 req = mtod(m, caddr_t); 999 len = m->m_len; 1000 optname = sopt->sopt_name; 1001 error = ipsec4_set_policy(inp, optname, req, len, priv); 1002 m_freem(m); 1003 break; 1004 } 1005 #endif /* IPSEC */ 1006 1007 default: 1008 error = ENOPROTOOPT; 1009 break; 1010 } 1011 break; 1012 1013 case SOPT_GET: 1014 switch (sopt->sopt_name) { 1015 case IP_OPTIONS: 1016 case IP_RETOPTS: 1017 if (inp->inp_options) 1018 error = sooptcopyout(sopt, 1019 mtod(inp->inp_options, 1020 char *), 1021 inp->inp_options->m_len); 1022 else 1023 sopt->sopt_valsize = 0; 1024 break; 1025 1026 case IP_TOS: 1027 case IP_TTL: 1028 case IP_MINTTL: 1029 case IP_RECVOPTS: 1030 case IP_RECVRETOPTS: 1031 case IP_RECVDSTADDR: 1032 case IP_RECVTTL: 1033 case IP_RECVIF: 1034 case IP_PORTRANGE: 1035 case IP_FAITH: 1036 case IP_ONESBCAST: 1037 case IP_DONTFRAG: 1038 switch (sopt->sopt_name) { 1039 1040 case IP_TOS: 1041 optval = inp->inp_ip_tos; 1042 break; 1043 1044 case IP_TTL: 1045 optval = inp->inp_ip_ttl; 1046 break; 1047 1048 case IP_MINTTL: 1049 optval = inp->inp_ip_minttl; 1050 break; 1051 1052 #define OPTBIT(bit) (inp->inp_flags & bit ? 1 : 0) 1053 1054 case IP_RECVOPTS: 1055 optval = OPTBIT(INP_RECVOPTS); 1056 break; 1057 1058 case IP_RECVRETOPTS: 1059 optval = OPTBIT(INP_RECVRETOPTS); 1060 break; 1061 1062 case IP_RECVDSTADDR: 1063 optval = OPTBIT(INP_RECVDSTADDR); 1064 break; 1065 1066 case IP_RECVTTL: 1067 optval = OPTBIT(INP_RECVTTL); 1068 break; 1069 1070 case IP_RECVIF: 1071 optval = OPTBIT(INP_RECVIF); 1072 break; 1073 1074 case IP_PORTRANGE: 1075 if (inp->inp_flags & INP_HIGHPORT) 1076 optval = IP_PORTRANGE_HIGH; 1077 else if (inp->inp_flags & INP_LOWPORT) 1078 optval = IP_PORTRANGE_LOW; 1079 else 1080 optval = 0; 1081 break; 1082 1083 case IP_FAITH: 1084 optval = OPTBIT(INP_FAITH); 1085 break; 1086 1087 case IP_ONESBCAST: 1088 optval = OPTBIT(INP_ONESBCAST); 1089 break; 1090 case IP_DONTFRAG: 1091 optval = OPTBIT(INP_DONTFRAG); 1092 break; 1093 } 1094 error = sooptcopyout(sopt, &optval, sizeof optval); 1095 break; 1096 1097 /* 1098 * Multicast socket options are processed by the in_mcast 1099 * module. 1100 */ 1101 case IP_MULTICAST_IF: 1102 case IP_MULTICAST_VIF: 1103 case IP_MULTICAST_TTL: 1104 case IP_MULTICAST_LOOP: 1105 case IP_MSFILTER: 1106 error = inp_getmoptions(inp, sopt); 1107 break; 1108 1109 #ifdef IPSEC 1110 case IP_IPSEC_POLICY: 1111 { 1112 struct mbuf *m = NULL; 1113 caddr_t req = NULL; 1114 size_t len = 0; 1115 1116 if (m != 0) { 1117 req = mtod(m, caddr_t); 1118 len = m->m_len; 1119 } 1120 error = ipsec4_get_policy(sotoinpcb(so), req, len, &m); 1121 if (error == 0) 1122 error = soopt_mcopyout(sopt, m); /* XXX */ 1123 if (error == 0) 1124 m_freem(m); 1125 break; 1126 } 1127 #endif /* IPSEC */ 1128 1129 default: 1130 error = ENOPROTOOPT; 1131 break; 1132 } 1133 break; 1134 } 1135 return (error); 1136 } 1137 1138 /* 1139 * Routine called from ip_output() to loop back a copy of an IP multicast 1140 * packet to the input queue of a specified interface. Note that this 1141 * calls the output routine of the loopback "driver", but with an interface 1142 * pointer that might NOT be a loopback interface -- evil, but easier than 1143 * replicating that code here. 1144 */ 1145 static void 1146 ip_mloopback(struct ifnet *ifp, struct mbuf *m, struct sockaddr_in *dst, 1147 int hlen) 1148 { 1149 register struct ip *ip; 1150 struct mbuf *copym; 1151 1152 copym = m_copy(m, 0, M_COPYALL); 1153 if (copym != NULL && (copym->m_flags & M_EXT || copym->m_len < hlen)) 1154 copym = m_pullup(copym, hlen); 1155 if (copym != NULL) { 1156 /* If needed, compute the checksum and mark it as valid. */ 1157 if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 1158 in_delayed_cksum(copym); 1159 copym->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 1160 copym->m_pkthdr.csum_flags |= 1161 CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 1162 copym->m_pkthdr.csum_data = 0xffff; 1163 } 1164 /* 1165 * We don't bother to fragment if the IP length is greater 1166 * than the interface's MTU. Can this possibly matter? 1167 */ 1168 ip = mtod(copym, struct ip *); 1169 ip->ip_len = htons(ip->ip_len); 1170 ip->ip_off = htons(ip->ip_off); 1171 ip->ip_sum = 0; 1172 ip->ip_sum = in_cksum(copym, hlen); 1173 /* 1174 * NB: 1175 * It's not clear whether there are any lingering 1176 * reentrancy problems in other areas which might 1177 * be exposed by using ip_input directly (in 1178 * particular, everything which modifies the packet 1179 * in-place). Yet another option is using the 1180 * protosw directly to deliver the looped back 1181 * packet. For the moment, we'll err on the side 1182 * of safety by using if_simloop(). 1183 */ 1184 #if 1 /* XXX */ 1185 if (dst->sin_family != AF_INET) { 1186 printf("ip_mloopback: bad address family %d\n", 1187 dst->sin_family); 1188 dst->sin_family = AF_INET; 1189 } 1190 #endif 1191 1192 #ifdef notdef 1193 copym->m_pkthdr.rcvif = ifp; 1194 ip_input(copym); 1195 #else 1196 if_simloop(ifp, copym, dst->sin_family, 0); 1197 #endif 1198 } 1199 } 1200