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_inet.h" 36 #include "opt_ipfw.h" 37 #include "opt_ipsec.h" 38 #include "opt_mbuf_stress_test.h" 39 #include "opt_mpath.h" 40 #include "opt_route.h" 41 #include "opt_sctp.h" 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/kernel.h> 46 #include <sys/malloc.h> 47 #include <sys/mbuf.h> 48 #include <sys/priv.h> 49 #include <sys/proc.h> 50 #include <sys/protosw.h> 51 #include <sys/sdt.h> 52 #include <sys/socket.h> 53 #include <sys/socketvar.h> 54 #include <sys/sysctl.h> 55 #include <sys/ucred.h> 56 57 #include <net/if.h> 58 #include <net/if_var.h> 59 #include <net/if_llatbl.h> 60 #include <net/netisr.h> 61 #include <net/pfil.h> 62 #include <net/route.h> 63 #include <net/flowtable.h> 64 #ifdef RADIX_MPATH 65 #include <net/radix_mpath.h> 66 #endif 67 #include <net/vnet.h> 68 69 #include <netinet/in.h> 70 #include <netinet/in_kdtrace.h> 71 #include <netinet/in_systm.h> 72 #include <netinet/ip.h> 73 #include <netinet/in_pcb.h> 74 #include <netinet/in_var.h> 75 #include <netinet/ip_var.h> 76 #include <netinet/ip_options.h> 77 #ifdef SCTP 78 #include <netinet/sctp.h> 79 #include <netinet/sctp_crc32.h> 80 #endif 81 82 #ifdef IPSEC 83 #include <netinet/ip_ipsec.h> 84 #include <netipsec/ipsec.h> 85 #endif /* IPSEC*/ 86 87 #include <machine/in_cksum.h> 88 89 #include <security/mac/mac_framework.h> 90 91 VNET_DEFINE(u_short, ip_id); 92 93 #ifdef MBUF_STRESS_TEST 94 static int mbuf_frag_size = 0; 95 SYSCTL_INT(_net_inet_ip, OID_AUTO, mbuf_frag_size, CTLFLAG_RW, 96 &mbuf_frag_size, 0, "Fragment outgoing mbufs to this size"); 97 #endif 98 99 static void ip_mloopback 100 (struct ifnet *, struct mbuf *, struct sockaddr_in *, int); 101 102 103 extern int in_mcast_loop; 104 extern struct protosw inetsw[]; 105 106 /* 107 * IP output. The packet in mbuf chain m contains a skeletal IP 108 * header (with len, off, ttl, proto, tos, src, dst). 109 * The mbuf chain containing the packet will be freed. 110 * The mbuf opt, if present, will not be freed. 111 * If route ro is present and has ro_rt initialized, route lookup would be 112 * skipped and ro->ro_rt would be used. If ro is present but ro->ro_rt is NULL, 113 * then result of route lookup is stored in ro->ro_rt. 114 * 115 * In the IP forwarding case, the packet will arrive with options already 116 * inserted, so must have a NULL opt pointer. 117 */ 118 int 119 ip_output(struct mbuf *m, struct mbuf *opt, struct route *ro, int flags, 120 struct ip_moptions *imo, struct inpcb *inp) 121 { 122 struct ip *ip; 123 struct ifnet *ifp = NULL; /* keep compiler happy */ 124 struct mbuf *m0; 125 int hlen = sizeof (struct ip); 126 int mtu; 127 int error = 0; 128 struct sockaddr_in *dst; 129 const struct sockaddr_in *gw; 130 struct in_ifaddr *ia; 131 int isbroadcast; 132 uint16_t ip_len, ip_off; 133 struct route iproute; 134 struct rtentry *rte; /* cache for ro->ro_rt */ 135 struct in_addr odst; 136 struct m_tag *fwd_tag = NULL; 137 #ifdef IPSEC 138 int no_route_but_check_spd = 0; 139 #endif 140 M_ASSERTPKTHDR(m); 141 142 if (inp != NULL) { 143 INP_LOCK_ASSERT(inp); 144 M_SETFIB(m, inp->inp_inc.inc_fibnum); 145 if (inp->inp_flags & (INP_HW_FLOWID|INP_SW_FLOWID)) { 146 m->m_pkthdr.flowid = inp->inp_flowid; 147 m->m_flags |= M_FLOWID; 148 } 149 } 150 151 if (ro == NULL) { 152 ro = &iproute; 153 bzero(ro, sizeof (*ro)); 154 } 155 156 #ifdef FLOWTABLE 157 if (ro->ro_rt == NULL) 158 (void )flowtable_lookup(AF_INET, m, ro); 159 #endif 160 161 if (opt) { 162 int len = 0; 163 m = ip_insertoptions(m, opt, &len); 164 if (len != 0) 165 hlen = len; /* ip->ip_hl is updated above */ 166 } 167 ip = mtod(m, struct ip *); 168 ip_len = ntohs(ip->ip_len); 169 ip_off = ntohs(ip->ip_off); 170 171 /* 172 * Fill in IP header. If we are not allowing fragmentation, 173 * then the ip_id field is meaningless, but we don't set it 174 * to zero. Doing so causes various problems when devices along 175 * the path (routers, load balancers, firewalls, etc.) illegally 176 * disable DF on our packet. Note that a 16-bit counter 177 * will wrap around in less than 10 seconds at 100 Mbit/s on a 178 * medium with MTU 1500. See Steven M. Bellovin, "A Technique 179 * for Counting NATted Hosts", Proc. IMW'02, available at 180 * <http://www.cs.columbia.edu/~smb/papers/fnat.pdf>. 181 */ 182 if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) { 183 ip->ip_v = IPVERSION; 184 ip->ip_hl = hlen >> 2; 185 ip->ip_id = ip_newid(); 186 IPSTAT_INC(ips_localout); 187 } else { 188 /* Header already set, fetch hlen from there */ 189 hlen = ip->ip_hl << 2; 190 } 191 192 /* 193 * dst/gw handling: 194 * 195 * dst can be rewritten but always points to &ro->ro_dst. 196 * gw is readonly but can point either to dst OR rt_gateway, 197 * therefore we need restore gw if we're redoing lookup. 198 */ 199 gw = dst = (struct sockaddr_in *)&ro->ro_dst; 200 again: 201 ia = NULL; 202 /* 203 * If there is a cached route, check that it is to the same 204 * destination and is still up. If not, free it and try again. 205 * The address family should also be checked in case of sharing 206 * the cache with IPv6. 207 */ 208 rte = ro->ro_rt; 209 if (rte && ((rte->rt_flags & RTF_UP) == 0 || 210 rte->rt_ifp == NULL || 211 !RT_LINK_IS_UP(rte->rt_ifp) || 212 dst->sin_family != AF_INET || 213 dst->sin_addr.s_addr != ip->ip_dst.s_addr)) { 214 RO_RTFREE(ro); 215 ro->ro_lle = NULL; 216 rte = NULL; 217 gw = dst; 218 } 219 if (rte == NULL && fwd_tag == NULL) { 220 bzero(dst, sizeof(*dst)); 221 dst->sin_family = AF_INET; 222 dst->sin_len = sizeof(*dst); 223 dst->sin_addr = ip->ip_dst; 224 } 225 /* 226 * If routing to interface only, short circuit routing lookup. 227 * The use of an all-ones broadcast address implies this; an 228 * interface is specified by the broadcast address of an interface, 229 * or the destination address of a ptp interface. 230 */ 231 if (flags & IP_SENDONES) { 232 if ((ia = ifatoia(ifa_ifwithbroadaddr(sintosa(dst)))) == NULL && 233 (ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst), 234 RT_DEFAULT_FIB))) == NULL) { 235 IPSTAT_INC(ips_noroute); 236 error = ENETUNREACH; 237 goto bad; 238 } 239 ip->ip_dst.s_addr = INADDR_BROADCAST; 240 dst->sin_addr = ip->ip_dst; 241 ifp = ia->ia_ifp; 242 ip->ip_ttl = 1; 243 isbroadcast = 1; 244 } else if (flags & IP_ROUTETOIF) { 245 if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst), 246 RT_DEFAULT_FIB))) == NULL && 247 (ia = ifatoia(ifa_ifwithnet(sintosa(dst), 0, 248 RT_DEFAULT_FIB))) == NULL) { 249 IPSTAT_INC(ips_noroute); 250 error = ENETUNREACH; 251 goto bad; 252 } 253 ifp = ia->ia_ifp; 254 ip->ip_ttl = 1; 255 isbroadcast = in_broadcast(dst->sin_addr, ifp); 256 } else if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) && 257 imo != NULL && imo->imo_multicast_ifp != NULL) { 258 /* 259 * Bypass the normal routing lookup for multicast 260 * packets if the interface is specified. 261 */ 262 ifp = imo->imo_multicast_ifp; 263 IFP_TO_IA(ifp, ia); 264 isbroadcast = 0; /* fool gcc */ 265 } else { 266 /* 267 * We want to do any cloning requested by the link layer, 268 * as this is probably required in all cases for correct 269 * operation (as it is for ARP). 270 */ 271 if (rte == NULL) { 272 #ifdef RADIX_MPATH 273 rtalloc_mpath_fib(ro, 274 ntohl(ip->ip_src.s_addr ^ ip->ip_dst.s_addr), 275 inp ? inp->inp_inc.inc_fibnum : M_GETFIB(m)); 276 #else 277 in_rtalloc_ign(ro, 0, 278 inp ? inp->inp_inc.inc_fibnum : M_GETFIB(m)); 279 #endif 280 rte = ro->ro_rt; 281 } 282 if (rte == NULL || 283 rte->rt_ifp == NULL || 284 !RT_LINK_IS_UP(rte->rt_ifp)) { 285 #ifdef IPSEC 286 /* 287 * There is no route for this packet, but it is 288 * possible that a matching SPD entry exists. 289 */ 290 no_route_but_check_spd = 1; 291 mtu = 0; /* Silence GCC warning. */ 292 goto sendit; 293 #endif 294 IPSTAT_INC(ips_noroute); 295 error = EHOSTUNREACH; 296 goto bad; 297 } 298 ia = ifatoia(rte->rt_ifa); 299 ifp = rte->rt_ifp; 300 counter_u64_add(rte->rt_pksent, 1); 301 if (rte->rt_flags & RTF_GATEWAY) 302 gw = (struct sockaddr_in *)rte->rt_gateway; 303 if (rte->rt_flags & RTF_HOST) 304 isbroadcast = (rte->rt_flags & RTF_BROADCAST); 305 else 306 isbroadcast = in_broadcast(gw->sin_addr, ifp); 307 } 308 /* 309 * Calculate MTU. If we have a route that is up, use that, 310 * otherwise use the interface's MTU. 311 */ 312 if (rte != NULL && (rte->rt_flags & (RTF_UP|RTF_HOST))) { 313 /* 314 * This case can happen if the user changed the MTU 315 * of an interface after enabling IP on it. Because 316 * most netifs don't keep track of routes pointing to 317 * them, there is no way for one to update all its 318 * routes when the MTU is changed. 319 */ 320 if (rte->rt_mtu > ifp->if_mtu) 321 rte->rt_mtu = ifp->if_mtu; 322 mtu = rte->rt_mtu; 323 } else { 324 mtu = ifp->if_mtu; 325 } 326 /* Catch a possible divide by zero later. */ 327 KASSERT(mtu > 0, ("%s: mtu %d <= 0, rte=%p (rt_flags=0x%08x) ifp=%p", 328 __func__, mtu, rte, (rte != NULL) ? rte->rt_flags : 0, ifp)); 329 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 330 m->m_flags |= M_MCAST; 331 /* 332 * IP destination address is multicast. Make sure "gw" 333 * still points to the address in "ro". (It may have been 334 * changed to point to a gateway address, above.) 335 */ 336 gw = dst; 337 /* 338 * See if the caller provided any multicast options 339 */ 340 if (imo != NULL) { 341 ip->ip_ttl = imo->imo_multicast_ttl; 342 if (imo->imo_multicast_vif != -1) 343 ip->ip_src.s_addr = 344 ip_mcast_src ? 345 ip_mcast_src(imo->imo_multicast_vif) : 346 INADDR_ANY; 347 } else 348 ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL; 349 /* 350 * Confirm that the outgoing interface supports multicast. 351 */ 352 if ((imo == NULL) || (imo->imo_multicast_vif == -1)) { 353 if ((ifp->if_flags & IFF_MULTICAST) == 0) { 354 IPSTAT_INC(ips_noroute); 355 error = ENETUNREACH; 356 goto bad; 357 } 358 } 359 /* 360 * If source address not specified yet, use address 361 * of outgoing 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 if ((imo == NULL && in_mcast_loop) || 370 (imo && imo->imo_multicast_loop)) { 371 /* 372 * Loop back multicast datagram if not expressly 373 * forbidden to do so, even if we are not a member 374 * of the group; ip_input() will filter it later, 375 * thus deferring a hash lookup and mutex acquisition 376 * at the expense of a cheap copy using m_copym(). 377 */ 378 ip_mloopback(ifp, m, dst, hlen); 379 } else { 380 /* 381 * If we are acting as a multicast router, perform 382 * multicast forwarding as if the packet had just 383 * arrived on the interface to which we are about 384 * to send. The multicast forwarding function 385 * recursively calls this function, using the 386 * IP_FORWARDING flag to prevent infinite recursion. 387 * 388 * Multicasts that are looped back by ip_mloopback(), 389 * above, will be forwarded by the ip_input() routine, 390 * if necessary. 391 */ 392 if (V_ip_mrouter && (flags & IP_FORWARDING) == 0) { 393 /* 394 * If rsvp daemon is not running, do not 395 * set ip_moptions. This ensures that the packet 396 * is multicast and not just sent down one link 397 * as prescribed by rsvpd. 398 */ 399 if (!V_rsvp_on) 400 imo = NULL; 401 if (ip_mforward && 402 ip_mforward(ip, ifp, m, imo) != 0) { 403 m_freem(m); 404 goto done; 405 } 406 } 407 } 408 409 /* 410 * Multicasts with a time-to-live of zero may be looped- 411 * back, above, but must not be transmitted on a network. 412 * Also, multicasts addressed to the loopback interface 413 * are not sent -- the above call to ip_mloopback() will 414 * loop back a copy. ip_input() will drop the copy if 415 * this host does not belong to the destination group on 416 * the loopback interface. 417 */ 418 if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) { 419 m_freem(m); 420 goto done; 421 } 422 423 goto sendit; 424 } 425 426 /* 427 * If the source address is not specified yet, use the address 428 * of the outoing interface. 429 */ 430 if (ip->ip_src.s_addr == INADDR_ANY) { 431 /* Interface may have no addresses. */ 432 if (ia != NULL) { 433 ip->ip_src = IA_SIN(ia)->sin_addr; 434 } 435 } 436 437 /* 438 * Both in the SMP world, pre-emption world if_transmit() world, 439 * the following code doesn't really function as intended any further. 440 * 441 * + There can and will be multiple CPUs running this code path 442 * in parallel, and we do no lock holding when checking the 443 * queue depth; 444 * + And since other threads can be running concurrently, even if 445 * we do pass this check, another thread may queue some frames 446 * before this thread does and it will end up partially or fully 447 * failing to send anyway; 448 * + if_transmit() based drivers don't necessarily set ifq_len 449 * at all. 450 * 451 * This should be replaced with a method of pushing an entire list 452 * of fragment frames to the driver and have the driver decide 453 * whether it can queue or not queue the entire set. 454 */ 455 #if 0 456 /* 457 * Verify that we have any chance at all of being able to queue the 458 * packet or packet fragments, unless ALTQ is enabled on the given 459 * interface in which case packetdrop should be done by queueing. 460 */ 461 n = ip_len / mtu + 1; /* how many fragments ? */ 462 if ( 463 #ifdef ALTQ 464 (!ALTQ_IS_ENABLED(&ifp->if_snd)) && 465 #endif /* ALTQ */ 466 (ifp->if_snd.ifq_len + n) >= ifp->if_snd.ifq_maxlen ) { 467 error = ENOBUFS; 468 IPSTAT_INC(ips_odropped); 469 ifp->if_snd.ifq_drops += n; 470 goto bad; 471 } 472 #endif 473 474 /* 475 * Look for broadcast address and 476 * verify user is allowed to send 477 * such a packet. 478 */ 479 if (isbroadcast) { 480 if ((ifp->if_flags & IFF_BROADCAST) == 0) { 481 error = EADDRNOTAVAIL; 482 goto bad; 483 } 484 if ((flags & IP_ALLOWBROADCAST) == 0) { 485 error = EACCES; 486 goto bad; 487 } 488 /* don't allow broadcast messages to be fragmented */ 489 if (ip_len > mtu) { 490 error = EMSGSIZE; 491 goto bad; 492 } 493 m->m_flags |= M_BCAST; 494 } else { 495 m->m_flags &= ~M_BCAST; 496 } 497 498 sendit: 499 #ifdef IPSEC 500 switch(ip_ipsec_output(&m, inp, &flags, &error)) { 501 case 1: 502 goto bad; 503 case -1: 504 goto done; 505 case 0: 506 default: 507 break; /* Continue with packet processing. */ 508 } 509 /* 510 * Check if there was a route for this packet; return error if not. 511 */ 512 if (no_route_but_check_spd) { 513 IPSTAT_INC(ips_noroute); 514 error = EHOSTUNREACH; 515 goto bad; 516 } 517 /* Update variables that are affected by ipsec4_output(). */ 518 ip = mtod(m, struct ip *); 519 hlen = ip->ip_hl << 2; 520 #endif /* IPSEC */ 521 522 /* Jump over all PFIL processing if hooks are not active. */ 523 if (!PFIL_HOOKED(&V_inet_pfil_hook)) 524 goto passout; 525 526 /* Run through list of hooks for output packets. */ 527 odst.s_addr = ip->ip_dst.s_addr; 528 error = pfil_run_hooks(&V_inet_pfil_hook, &m, ifp, PFIL_OUT, inp); 529 if (error != 0 || m == NULL) 530 goto done; 531 532 ip = mtod(m, struct ip *); 533 534 /* See if destination IP address was changed by packet filter. */ 535 if (odst.s_addr != ip->ip_dst.s_addr) { 536 m->m_flags |= M_SKIP_FIREWALL; 537 /* If destination is now ourself drop to ip_input(). */ 538 if (in_localip(ip->ip_dst)) { 539 m->m_flags |= M_FASTFWD_OURS; 540 if (m->m_pkthdr.rcvif == NULL) 541 m->m_pkthdr.rcvif = V_loif; 542 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 543 m->m_pkthdr.csum_flags |= 544 CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 545 m->m_pkthdr.csum_data = 0xffff; 546 } 547 m->m_pkthdr.csum_flags |= 548 CSUM_IP_CHECKED | CSUM_IP_VALID; 549 #ifdef SCTP 550 if (m->m_pkthdr.csum_flags & CSUM_SCTP) 551 m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID; 552 #endif 553 error = netisr_queue(NETISR_IP, m); 554 goto done; 555 } else 556 goto again; /* Redo the routing table lookup. */ 557 } 558 559 /* See if local, if yes, send it to netisr with IP_FASTFWD_OURS. */ 560 if (m->m_flags & M_FASTFWD_OURS) { 561 if (m->m_pkthdr.rcvif == NULL) 562 m->m_pkthdr.rcvif = V_loif; 563 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 564 m->m_pkthdr.csum_flags |= 565 CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 566 m->m_pkthdr.csum_data = 0xffff; 567 } 568 #ifdef SCTP 569 if (m->m_pkthdr.csum_flags & CSUM_SCTP) 570 m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID; 571 #endif 572 m->m_pkthdr.csum_flags |= 573 CSUM_IP_CHECKED | CSUM_IP_VALID; 574 575 error = netisr_queue(NETISR_IP, m); 576 goto done; 577 } 578 /* Or forward to some other address? */ 579 if ((m->m_flags & M_IP_NEXTHOP) && 580 (fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL)) != NULL) { 581 bcopy((fwd_tag+1), dst, sizeof(struct sockaddr_in)); 582 m->m_flags |= M_SKIP_FIREWALL; 583 m->m_flags &= ~M_IP_NEXTHOP; 584 m_tag_delete(m, fwd_tag); 585 goto again; 586 } 587 588 passout: 589 /* 127/8 must not appear on wire - RFC1122. */ 590 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 591 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 592 if ((ifp->if_flags & IFF_LOOPBACK) == 0) { 593 IPSTAT_INC(ips_badaddr); 594 error = EADDRNOTAVAIL; 595 goto bad; 596 } 597 } 598 599 m->m_pkthdr.csum_flags |= CSUM_IP; 600 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA & ~ifp->if_hwassist) { 601 in_delayed_cksum(m); 602 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 603 } 604 #ifdef SCTP 605 if (m->m_pkthdr.csum_flags & CSUM_SCTP & ~ifp->if_hwassist) { 606 sctp_delayed_cksum(m, (uint32_t)(ip->ip_hl << 2)); 607 m->m_pkthdr.csum_flags &= ~CSUM_SCTP; 608 } 609 #endif 610 611 /* 612 * If small enough for interface, or the interface will take 613 * care of the fragmentation for us, we can just send directly. 614 */ 615 if (ip_len <= mtu || 616 (m->m_pkthdr.csum_flags & ifp->if_hwassist & CSUM_TSO) != 0 || 617 ((ip_off & IP_DF) == 0 && (ifp->if_hwassist & CSUM_FRAGMENT))) { 618 ip->ip_sum = 0; 619 if (m->m_pkthdr.csum_flags & CSUM_IP & ~ifp->if_hwassist) { 620 ip->ip_sum = in_cksum(m, hlen); 621 m->m_pkthdr.csum_flags &= ~CSUM_IP; 622 } 623 624 /* 625 * Record statistics for this interface address. 626 * With CSUM_TSO the byte/packet count will be slightly 627 * incorrect because we count the IP+TCP headers only 628 * once instead of for every generated packet. 629 */ 630 if (!(flags & IP_FORWARDING) && ia) { 631 if (m->m_pkthdr.csum_flags & CSUM_TSO) 632 counter_u64_add(ia->ia_ifa.ifa_opackets, 633 m->m_pkthdr.len / m->m_pkthdr.tso_segsz); 634 else 635 counter_u64_add(ia->ia_ifa.ifa_opackets, 1); 636 637 counter_u64_add(ia->ia_ifa.ifa_obytes, m->m_pkthdr.len); 638 } 639 #ifdef MBUF_STRESS_TEST 640 if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size) 641 m = m_fragment(m, M_NOWAIT, mbuf_frag_size); 642 #endif 643 /* 644 * Reset layer specific mbuf flags 645 * to avoid confusing lower layers. 646 */ 647 m_clrprotoflags(m); 648 IP_PROBE(send, NULL, NULL, ip, ifp, ip, NULL); 649 error = (*ifp->if_output)(ifp, m, 650 (const struct sockaddr *)gw, ro); 651 goto done; 652 } 653 654 /* Balk when DF bit is set or the interface didn't support TSO. */ 655 if ((ip_off & IP_DF) || (m->m_pkthdr.csum_flags & CSUM_TSO)) { 656 error = EMSGSIZE; 657 IPSTAT_INC(ips_cantfrag); 658 goto bad; 659 } 660 661 /* 662 * Too large for interface; fragment if possible. If successful, 663 * on return, m will point to a list of packets to be sent. 664 */ 665 error = ip_fragment(ip, &m, mtu, ifp->if_hwassist); 666 if (error) 667 goto bad; 668 for (; m; m = m0) { 669 m0 = m->m_nextpkt; 670 m->m_nextpkt = 0; 671 if (error == 0) { 672 /* Record statistics for this interface address. */ 673 if (ia != NULL) { 674 counter_u64_add(ia->ia_ifa.ifa_opackets, 1); 675 counter_u64_add(ia->ia_ifa.ifa_obytes, 676 m->m_pkthdr.len); 677 } 678 /* 679 * Reset layer specific mbuf flags 680 * to avoid confusing upper layers. 681 */ 682 m_clrprotoflags(m); 683 684 IP_PROBE(send, NULL, NULL, ip, ifp, ip, NULL); 685 error = (*ifp->if_output)(ifp, m, 686 (const struct sockaddr *)gw, ro); 687 } else 688 m_freem(m); 689 } 690 691 if (error == 0) 692 IPSTAT_INC(ips_fragmented); 693 694 done: 695 if (ro == &iproute) 696 RO_RTFREE(ro); 697 return (error); 698 bad: 699 m_freem(m); 700 goto done; 701 } 702 703 /* 704 * Create a chain of fragments which fit the given mtu. m_frag points to the 705 * mbuf to be fragmented; on return it points to the chain with the fragments. 706 * Return 0 if no error. If error, m_frag may contain a partially built 707 * chain of fragments that should be freed by the caller. 708 * 709 * if_hwassist_flags is the hw offload capabilities (see if_data.ifi_hwassist) 710 */ 711 int 712 ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu, 713 u_long if_hwassist_flags) 714 { 715 int error = 0; 716 int hlen = ip->ip_hl << 2; 717 int len = (mtu - hlen) & ~7; /* size of payload in each fragment */ 718 int off; 719 struct mbuf *m0 = *m_frag; /* the original packet */ 720 int firstlen; 721 struct mbuf **mnext; 722 int nfrags; 723 uint16_t ip_len, ip_off; 724 725 ip_len = ntohs(ip->ip_len); 726 ip_off = ntohs(ip->ip_off); 727 728 if (ip_off & IP_DF) { /* Fragmentation not allowed */ 729 IPSTAT_INC(ips_cantfrag); 730 return EMSGSIZE; 731 } 732 733 /* 734 * Must be able to put at least 8 bytes per fragment. 735 */ 736 if (len < 8) 737 return EMSGSIZE; 738 739 /* 740 * If the interface will not calculate checksums on 741 * fragmented packets, then do it here. 742 */ 743 if (m0->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 744 in_delayed_cksum(m0); 745 m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 746 } 747 #ifdef SCTP 748 if (m0->m_pkthdr.csum_flags & CSUM_SCTP) { 749 sctp_delayed_cksum(m0, hlen); 750 m0->m_pkthdr.csum_flags &= ~CSUM_SCTP; 751 } 752 #endif 753 if (len > PAGE_SIZE) { 754 /* 755 * Fragment large datagrams such that each segment 756 * contains a multiple of PAGE_SIZE amount of data, 757 * plus headers. This enables a receiver to perform 758 * page-flipping zero-copy optimizations. 759 * 760 * XXX When does this help given that sender and receiver 761 * could have different page sizes, and also mtu could 762 * be less than the receiver's page size ? 763 */ 764 int newlen; 765 struct mbuf *m; 766 767 for (m = m0, off = 0; m && (off+m->m_len) <= mtu; m = m->m_next) 768 off += m->m_len; 769 770 /* 771 * firstlen (off - hlen) must be aligned on an 772 * 8-byte boundary 773 */ 774 if (off < hlen) 775 goto smart_frag_failure; 776 off = ((off - hlen) & ~7) + hlen; 777 newlen = (~PAGE_MASK) & mtu; 778 if ((newlen + sizeof (struct ip)) > mtu) { 779 /* we failed, go back the default */ 780 smart_frag_failure: 781 newlen = len; 782 off = hlen + len; 783 } 784 len = newlen; 785 786 } else { 787 off = hlen + len; 788 } 789 790 firstlen = off - hlen; 791 mnext = &m0->m_nextpkt; /* pointer to next packet */ 792 793 /* 794 * Loop through length of segment after first fragment, 795 * make new header and copy data of each part and link onto chain. 796 * Here, m0 is the original packet, m is the fragment being created. 797 * The fragments are linked off the m_nextpkt of the original 798 * packet, which after processing serves as the first fragment. 799 */ 800 for (nfrags = 1; off < ip_len; off += len, nfrags++) { 801 struct ip *mhip; /* ip header on the fragment */ 802 struct mbuf *m; 803 int mhlen = sizeof (struct ip); 804 805 m = m_gethdr(M_NOWAIT, MT_DATA); 806 if (m == NULL) { 807 error = ENOBUFS; 808 IPSTAT_INC(ips_odropped); 809 goto done; 810 } 811 m->m_flags |= (m0->m_flags & M_MCAST); 812 /* 813 * In the first mbuf, leave room for the link header, then 814 * copy the original IP header including options. The payload 815 * goes into an additional mbuf chain returned by m_copym(). 816 */ 817 m->m_data += max_linkhdr; 818 mhip = mtod(m, struct ip *); 819 *mhip = *ip; 820 if (hlen > sizeof (struct ip)) { 821 mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip); 822 mhip->ip_v = IPVERSION; 823 mhip->ip_hl = mhlen >> 2; 824 } 825 m->m_len = mhlen; 826 /* XXX do we need to add ip_off below ? */ 827 mhip->ip_off = ((off - hlen) >> 3) + ip_off; 828 if (off + len >= ip_len) 829 len = ip_len - off; 830 else 831 mhip->ip_off |= IP_MF; 832 mhip->ip_len = htons((u_short)(len + mhlen)); 833 m->m_next = m_copym(m0, off, len, M_NOWAIT); 834 if (m->m_next == NULL) { /* copy failed */ 835 m_free(m); 836 error = ENOBUFS; /* ??? */ 837 IPSTAT_INC(ips_odropped); 838 goto done; 839 } 840 m->m_pkthdr.len = mhlen + len; 841 m->m_pkthdr.rcvif = NULL; 842 #ifdef MAC 843 mac_netinet_fragment(m0, m); 844 #endif 845 m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags; 846 mhip->ip_off = htons(mhip->ip_off); 847 mhip->ip_sum = 0; 848 if (m->m_pkthdr.csum_flags & CSUM_IP & ~if_hwassist_flags) { 849 mhip->ip_sum = in_cksum(m, mhlen); 850 m->m_pkthdr.csum_flags &= ~CSUM_IP; 851 } 852 *mnext = m; 853 mnext = &m->m_nextpkt; 854 } 855 IPSTAT_ADD(ips_ofragments, nfrags); 856 857 /* 858 * Update first fragment by trimming what's been copied out 859 * and updating header. 860 */ 861 m_adj(m0, hlen + firstlen - ip_len); 862 m0->m_pkthdr.len = hlen + firstlen; 863 ip->ip_len = htons((u_short)m0->m_pkthdr.len); 864 ip->ip_off = htons(ip_off | IP_MF); 865 ip->ip_sum = 0; 866 if (m0->m_pkthdr.csum_flags & CSUM_IP & ~if_hwassist_flags) { 867 ip->ip_sum = in_cksum(m0, hlen); 868 m0->m_pkthdr.csum_flags &= ~CSUM_IP; 869 } 870 871 done: 872 *m_frag = m0; 873 return error; 874 } 875 876 void 877 in_delayed_cksum(struct mbuf *m) 878 { 879 struct ip *ip; 880 uint16_t csum, offset, ip_len; 881 882 ip = mtod(m, struct ip *); 883 offset = ip->ip_hl << 2 ; 884 ip_len = ntohs(ip->ip_len); 885 csum = in_cksum_skip(m, ip_len, offset); 886 if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0) 887 csum = 0xffff; 888 offset += m->m_pkthdr.csum_data; /* checksum offset */ 889 890 if (offset + sizeof(u_short) > m->m_len) { 891 printf("delayed m_pullup, m->len: %d off: %d p: %d\n", 892 m->m_len, offset, ip->ip_p); 893 /* 894 * XXX 895 * this shouldn't happen, but if it does, the 896 * correct behavior may be to insert the checksum 897 * in the appropriate next mbuf in the chain. 898 */ 899 return; 900 } 901 *(u_short *)(m->m_data + offset) = csum; 902 } 903 904 /* 905 * IP socket option processing. 906 */ 907 int 908 ip_ctloutput(struct socket *so, struct sockopt *sopt) 909 { 910 struct inpcb *inp = sotoinpcb(so); 911 int error, optval; 912 913 error = optval = 0; 914 if (sopt->sopt_level != IPPROTO_IP) { 915 error = EINVAL; 916 917 if (sopt->sopt_level == SOL_SOCKET && 918 sopt->sopt_dir == SOPT_SET) { 919 switch (sopt->sopt_name) { 920 case SO_REUSEADDR: 921 INP_WLOCK(inp); 922 if ((so->so_options & SO_REUSEADDR) != 0) 923 inp->inp_flags2 |= INP_REUSEADDR; 924 else 925 inp->inp_flags2 &= ~INP_REUSEADDR; 926 INP_WUNLOCK(inp); 927 error = 0; 928 break; 929 case SO_REUSEPORT: 930 INP_WLOCK(inp); 931 if ((so->so_options & SO_REUSEPORT) != 0) 932 inp->inp_flags2 |= INP_REUSEPORT; 933 else 934 inp->inp_flags2 &= ~INP_REUSEPORT; 935 INP_WUNLOCK(inp); 936 error = 0; 937 break; 938 case SO_SETFIB: 939 INP_WLOCK(inp); 940 inp->inp_inc.inc_fibnum = so->so_fibnum; 941 INP_WUNLOCK(inp); 942 error = 0; 943 break; 944 default: 945 break; 946 } 947 } 948 return (error); 949 } 950 951 switch (sopt->sopt_dir) { 952 case SOPT_SET: 953 switch (sopt->sopt_name) { 954 case IP_OPTIONS: 955 #ifdef notyet 956 case IP_RETOPTS: 957 #endif 958 { 959 struct mbuf *m; 960 if (sopt->sopt_valsize > MLEN) { 961 error = EMSGSIZE; 962 break; 963 } 964 m = m_get(sopt->sopt_td ? M_WAITOK : M_NOWAIT, MT_DATA); 965 if (m == NULL) { 966 error = ENOBUFS; 967 break; 968 } 969 m->m_len = sopt->sopt_valsize; 970 error = sooptcopyin(sopt, mtod(m, char *), m->m_len, 971 m->m_len); 972 if (error) { 973 m_free(m); 974 break; 975 } 976 INP_WLOCK(inp); 977 error = ip_pcbopts(inp, sopt->sopt_name, m); 978 INP_WUNLOCK(inp); 979 return (error); 980 } 981 982 case IP_BINDANY: 983 if (sopt->sopt_td != NULL) { 984 error = priv_check(sopt->sopt_td, 985 PRIV_NETINET_BINDANY); 986 if (error) 987 break; 988 } 989 /* FALLTHROUGH */ 990 case IP_TOS: 991 case IP_TTL: 992 case IP_MINTTL: 993 case IP_RECVOPTS: 994 case IP_RECVRETOPTS: 995 case IP_RECVDSTADDR: 996 case IP_RECVTTL: 997 case IP_RECVIF: 998 case IP_FAITH: 999 case IP_ONESBCAST: 1000 case IP_DONTFRAG: 1001 case IP_RECVTOS: 1002 error = sooptcopyin(sopt, &optval, sizeof optval, 1003 sizeof optval); 1004 if (error) 1005 break; 1006 1007 switch (sopt->sopt_name) { 1008 case IP_TOS: 1009 inp->inp_ip_tos = optval; 1010 break; 1011 1012 case IP_TTL: 1013 inp->inp_ip_ttl = optval; 1014 break; 1015 1016 case IP_MINTTL: 1017 if (optval >= 0 && optval <= MAXTTL) 1018 inp->inp_ip_minttl = optval; 1019 else 1020 error = EINVAL; 1021 break; 1022 1023 #define OPTSET(bit) do { \ 1024 INP_WLOCK(inp); \ 1025 if (optval) \ 1026 inp->inp_flags |= bit; \ 1027 else \ 1028 inp->inp_flags &= ~bit; \ 1029 INP_WUNLOCK(inp); \ 1030 } while (0) 1031 1032 case IP_RECVOPTS: 1033 OPTSET(INP_RECVOPTS); 1034 break; 1035 1036 case IP_RECVRETOPTS: 1037 OPTSET(INP_RECVRETOPTS); 1038 break; 1039 1040 case IP_RECVDSTADDR: 1041 OPTSET(INP_RECVDSTADDR); 1042 break; 1043 1044 case IP_RECVTTL: 1045 OPTSET(INP_RECVTTL); 1046 break; 1047 1048 case IP_RECVIF: 1049 OPTSET(INP_RECVIF); 1050 break; 1051 1052 case IP_FAITH: 1053 OPTSET(INP_FAITH); 1054 break; 1055 1056 case IP_ONESBCAST: 1057 OPTSET(INP_ONESBCAST); 1058 break; 1059 case IP_DONTFRAG: 1060 OPTSET(INP_DONTFRAG); 1061 break; 1062 case IP_BINDANY: 1063 OPTSET(INP_BINDANY); 1064 break; 1065 case IP_RECVTOS: 1066 OPTSET(INP_RECVTOS); 1067 break; 1068 } 1069 break; 1070 #undef OPTSET 1071 1072 /* 1073 * Multicast socket options are processed by the in_mcast 1074 * module. 1075 */ 1076 case IP_MULTICAST_IF: 1077 case IP_MULTICAST_VIF: 1078 case IP_MULTICAST_TTL: 1079 case IP_MULTICAST_LOOP: 1080 case IP_ADD_MEMBERSHIP: 1081 case IP_DROP_MEMBERSHIP: 1082 case IP_ADD_SOURCE_MEMBERSHIP: 1083 case IP_DROP_SOURCE_MEMBERSHIP: 1084 case IP_BLOCK_SOURCE: 1085 case IP_UNBLOCK_SOURCE: 1086 case IP_MSFILTER: 1087 case MCAST_JOIN_GROUP: 1088 case MCAST_LEAVE_GROUP: 1089 case MCAST_JOIN_SOURCE_GROUP: 1090 case MCAST_LEAVE_SOURCE_GROUP: 1091 case MCAST_BLOCK_SOURCE: 1092 case MCAST_UNBLOCK_SOURCE: 1093 error = inp_setmoptions(inp, sopt); 1094 break; 1095 1096 case IP_PORTRANGE: 1097 error = sooptcopyin(sopt, &optval, sizeof optval, 1098 sizeof optval); 1099 if (error) 1100 break; 1101 1102 INP_WLOCK(inp); 1103 switch (optval) { 1104 case IP_PORTRANGE_DEFAULT: 1105 inp->inp_flags &= ~(INP_LOWPORT); 1106 inp->inp_flags &= ~(INP_HIGHPORT); 1107 break; 1108 1109 case IP_PORTRANGE_HIGH: 1110 inp->inp_flags &= ~(INP_LOWPORT); 1111 inp->inp_flags |= INP_HIGHPORT; 1112 break; 1113 1114 case IP_PORTRANGE_LOW: 1115 inp->inp_flags &= ~(INP_HIGHPORT); 1116 inp->inp_flags |= INP_LOWPORT; 1117 break; 1118 1119 default: 1120 error = EINVAL; 1121 break; 1122 } 1123 INP_WUNLOCK(inp); 1124 break; 1125 1126 #ifdef IPSEC 1127 case IP_IPSEC_POLICY: 1128 { 1129 caddr_t req; 1130 struct mbuf *m; 1131 1132 if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */ 1133 break; 1134 if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */ 1135 break; 1136 req = mtod(m, caddr_t); 1137 error = ipsec_set_policy(inp, sopt->sopt_name, req, 1138 m->m_len, (sopt->sopt_td != NULL) ? 1139 sopt->sopt_td->td_ucred : NULL); 1140 m_freem(m); 1141 break; 1142 } 1143 #endif /* IPSEC */ 1144 1145 default: 1146 error = ENOPROTOOPT; 1147 break; 1148 } 1149 break; 1150 1151 case SOPT_GET: 1152 switch (sopt->sopt_name) { 1153 case IP_OPTIONS: 1154 case IP_RETOPTS: 1155 if (inp->inp_options) 1156 error = sooptcopyout(sopt, 1157 mtod(inp->inp_options, 1158 char *), 1159 inp->inp_options->m_len); 1160 else 1161 sopt->sopt_valsize = 0; 1162 break; 1163 1164 case IP_TOS: 1165 case IP_TTL: 1166 case IP_MINTTL: 1167 case IP_RECVOPTS: 1168 case IP_RECVRETOPTS: 1169 case IP_RECVDSTADDR: 1170 case IP_RECVTTL: 1171 case IP_RECVIF: 1172 case IP_PORTRANGE: 1173 case IP_FAITH: 1174 case IP_ONESBCAST: 1175 case IP_DONTFRAG: 1176 case IP_BINDANY: 1177 case IP_RECVTOS: 1178 switch (sopt->sopt_name) { 1179 1180 case IP_TOS: 1181 optval = inp->inp_ip_tos; 1182 break; 1183 1184 case IP_TTL: 1185 optval = inp->inp_ip_ttl; 1186 break; 1187 1188 case IP_MINTTL: 1189 optval = inp->inp_ip_minttl; 1190 break; 1191 1192 #define OPTBIT(bit) (inp->inp_flags & bit ? 1 : 0) 1193 1194 case IP_RECVOPTS: 1195 optval = OPTBIT(INP_RECVOPTS); 1196 break; 1197 1198 case IP_RECVRETOPTS: 1199 optval = OPTBIT(INP_RECVRETOPTS); 1200 break; 1201 1202 case IP_RECVDSTADDR: 1203 optval = OPTBIT(INP_RECVDSTADDR); 1204 break; 1205 1206 case IP_RECVTTL: 1207 optval = OPTBIT(INP_RECVTTL); 1208 break; 1209 1210 case IP_RECVIF: 1211 optval = OPTBIT(INP_RECVIF); 1212 break; 1213 1214 case IP_PORTRANGE: 1215 if (inp->inp_flags & INP_HIGHPORT) 1216 optval = IP_PORTRANGE_HIGH; 1217 else if (inp->inp_flags & INP_LOWPORT) 1218 optval = IP_PORTRANGE_LOW; 1219 else 1220 optval = 0; 1221 break; 1222 1223 case IP_FAITH: 1224 optval = OPTBIT(INP_FAITH); 1225 break; 1226 1227 case IP_ONESBCAST: 1228 optval = OPTBIT(INP_ONESBCAST); 1229 break; 1230 case IP_DONTFRAG: 1231 optval = OPTBIT(INP_DONTFRAG); 1232 break; 1233 case IP_BINDANY: 1234 optval = OPTBIT(INP_BINDANY); 1235 break; 1236 case IP_RECVTOS: 1237 optval = OPTBIT(INP_RECVTOS); 1238 break; 1239 } 1240 error = sooptcopyout(sopt, &optval, sizeof optval); 1241 break; 1242 1243 /* 1244 * Multicast socket options are processed by the in_mcast 1245 * module. 1246 */ 1247 case IP_MULTICAST_IF: 1248 case IP_MULTICAST_VIF: 1249 case IP_MULTICAST_TTL: 1250 case IP_MULTICAST_LOOP: 1251 case IP_MSFILTER: 1252 error = inp_getmoptions(inp, sopt); 1253 break; 1254 1255 #ifdef IPSEC 1256 case IP_IPSEC_POLICY: 1257 { 1258 struct mbuf *m = NULL; 1259 caddr_t req = NULL; 1260 size_t len = 0; 1261 1262 if (m != 0) { 1263 req = mtod(m, caddr_t); 1264 len = m->m_len; 1265 } 1266 error = ipsec_get_policy(sotoinpcb(so), req, len, &m); 1267 if (error == 0) 1268 error = soopt_mcopyout(sopt, m); /* XXX */ 1269 if (error == 0) 1270 m_freem(m); 1271 break; 1272 } 1273 #endif /* IPSEC */ 1274 1275 default: 1276 error = ENOPROTOOPT; 1277 break; 1278 } 1279 break; 1280 } 1281 return (error); 1282 } 1283 1284 /* 1285 * Routine called from ip_output() to loop back a copy of an IP multicast 1286 * packet to the input queue of a specified interface. Note that this 1287 * calls the output routine of the loopback "driver", but with an interface 1288 * pointer that might NOT be a loopback interface -- evil, but easier than 1289 * replicating that code here. 1290 */ 1291 static void 1292 ip_mloopback(struct ifnet *ifp, struct mbuf *m, struct sockaddr_in *dst, 1293 int hlen) 1294 { 1295 register struct ip *ip; 1296 struct mbuf *copym; 1297 1298 /* 1299 * Make a deep copy of the packet because we're going to 1300 * modify the pack in order to generate checksums. 1301 */ 1302 copym = m_dup(m, M_NOWAIT); 1303 if (copym != NULL && (copym->m_flags & M_EXT || copym->m_len < hlen)) 1304 copym = m_pullup(copym, hlen); 1305 if (copym != NULL) { 1306 /* If needed, compute the checksum and mark it as valid. */ 1307 if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 1308 in_delayed_cksum(copym); 1309 copym->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 1310 copym->m_pkthdr.csum_flags |= 1311 CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 1312 copym->m_pkthdr.csum_data = 0xffff; 1313 } 1314 /* 1315 * We don't bother to fragment if the IP length is greater 1316 * than the interface's MTU. Can this possibly matter? 1317 */ 1318 ip = mtod(copym, struct ip *); 1319 ip->ip_sum = 0; 1320 ip->ip_sum = in_cksum(copym, hlen); 1321 #if 1 /* XXX */ 1322 if (dst->sin_family != AF_INET) { 1323 printf("ip_mloopback: bad address family %d\n", 1324 dst->sin_family); 1325 dst->sin_family = AF_INET; 1326 } 1327 #endif 1328 if_simloop(ifp, copym, dst->sin_family, 0); 1329 } 1330 } 1331