ip_output.c revision 241344
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: head/sys/netinet/ip_output.c 241344 2012-10-08 08:03:58Z glebius $"); 34 35#include "opt_ipfw.h" 36#include "opt_ipsec.h" 37#include "opt_route.h" 38#include "opt_mbuf_stress_test.h" 39#include "opt_mpath.h" 40#include "opt_sctp.h" 41 42#include <sys/param.h> 43#include <sys/systm.h> 44#include <sys/kernel.h> 45#include <sys/malloc.h> 46#include <sys/mbuf.h> 47#include <sys/priv.h> 48#include <sys/proc.h> 49#include <sys/protosw.h> 50#include <sys/socket.h> 51#include <sys/socketvar.h> 52#include <sys/sysctl.h> 53#include <sys/ucred.h> 54 55#include <net/if.h> 56#include <net/if_llatbl.h> 57#include <net/netisr.h> 58#include <net/pfil.h> 59#include <net/route.h> 60#include <net/flowtable.h> 61#ifdef RADIX_MPATH 62#include <net/radix_mpath.h> 63#endif 64#include <net/vnet.h> 65 66#include <netinet/in.h> 67#include <netinet/in_systm.h> 68#include <netinet/ip.h> 69#include <netinet/in_pcb.h> 70#include <netinet/in_var.h> 71#include <netinet/ip_var.h> 72#include <netinet/ip_options.h> 73#ifdef SCTP 74#include <netinet/sctp.h> 75#include <netinet/sctp_crc32.h> 76#endif 77 78#ifdef IPSEC 79#include <netinet/ip_ipsec.h> 80#include <netipsec/ipsec.h> 81#endif /* IPSEC*/ 82 83#include <machine/in_cksum.h> 84 85#include <security/mac/mac_framework.h> 86 87VNET_DEFINE(u_short, ip_id); 88 89#ifdef MBUF_STRESS_TEST 90static int mbuf_frag_size = 0; 91SYSCTL_INT(_net_inet_ip, OID_AUTO, mbuf_frag_size, CTLFLAG_RW, 92 &mbuf_frag_size, 0, "Fragment outgoing mbufs to this size"); 93#endif 94 95static void ip_mloopback 96 (struct ifnet *, struct mbuf *, struct sockaddr_in *, int); 97 98 99extern int in_mcast_loop; 100extern struct protosw inetsw[]; 101 102/* 103 * IP output. The packet in mbuf chain m contains a skeletal IP 104 * header (with len, off, ttl, proto, tos, src, dst). 105 * ip_len and ip_off are in host format. 106 * The mbuf chain containing the packet will be freed. 107 * The mbuf opt, if present, will not be freed. 108 * If route ro is present and has ro_rt initialized, route lookup would be 109 * skipped and ro->ro_rt would be used. If ro is present but ro->ro_rt is NULL, 110 * then result of route lookup is stored in ro->ro_rt. 111 * 112 * In the IP forwarding case, the packet will arrive with options already 113 * inserted, so must have a NULL opt pointer. 114 */ 115int 116ip_output(struct mbuf *m, struct mbuf *opt, struct route *ro, int flags, 117 struct ip_moptions *imo, struct inpcb *inp) 118{ 119 struct ip *ip; 120 struct ifnet *ifp = NULL; /* keep compiler happy */ 121 struct mbuf *m0; 122 int hlen = sizeof (struct ip); 123 int mtu; 124 int n; /* scratchpad */ 125 int error = 0; 126 struct sockaddr_in *dst; 127 struct in_ifaddr *ia; 128 int isbroadcast; 129 uint16_t ip_len, ip_off, sw_csum; 130 struct route iproute; 131 struct rtentry *rte; /* cache for ro->ro_rt */ 132 struct in_addr odst; 133#ifdef IPFIREWALL_FORWARD 134 struct m_tag *fwd_tag = NULL; 135#endif 136#ifdef IPSEC 137 int no_route_but_check_spd = 0; 138#endif 139 M_ASSERTPKTHDR(m); 140 141 if (inp != NULL) { 142 INP_LOCK_ASSERT(inp); 143 M_SETFIB(m, inp->inp_inc.inc_fibnum); 144 if (inp->inp_flags & (INP_HW_FLOWID|INP_SW_FLOWID)) { 145 m->m_pkthdr.flowid = inp->inp_flowid; 146 m->m_flags |= M_FLOWID; 147 } 148 } 149 150 if (ro == NULL) { 151 ro = &iproute; 152 bzero(ro, sizeof (*ro)); 153 } 154 155#ifdef FLOWTABLE 156 if (ro->ro_rt == NULL) { 157 struct flentry *fle; 158 159 /* 160 * The flow table returns route entries valid for up to 30 161 * seconds; we rely on the remainder of ip_output() taking no 162 * longer than that long for the stability of ro_rt. The 163 * flow ID assignment must have happened before this point. 164 */ 165 fle = flowtable_lookup_mbuf(V_ip_ft, m, AF_INET); 166 if (fle != NULL) 167 flow_to_route(fle, ro); 168 } 169#endif 170 171 if (opt) { 172 int len = 0; 173 m = ip_insertoptions(m, opt, &len); 174 if (len != 0) 175 hlen = len; /* ip->ip_hl is updated above */ 176 } 177 ip = mtod(m, struct ip *); 178 179 /* 180 * Fill in IP header. If we are not allowing fragmentation, 181 * then the ip_id field is meaningless, but we don't set it 182 * to zero. Doing so causes various problems when devices along 183 * the path (routers, load balancers, firewalls, etc.) illegally 184 * disable DF on our packet. Note that a 16-bit counter 185 * will wrap around in less than 10 seconds at 100 Mbit/s on a 186 * medium with MTU 1500. See Steven M. Bellovin, "A Technique 187 * for Counting NATted Hosts", Proc. IMW'02, available at 188 * <http://www.cs.columbia.edu/~smb/papers/fnat.pdf>. 189 */ 190 if ((flags & (IP_FORWARDING|IP_RAWOUTPUT)) == 0) { 191 ip->ip_v = IPVERSION; 192 ip->ip_hl = hlen >> 2; 193 ip->ip_id = ip_newid(); 194 IPSTAT_INC(ips_localout); 195 } else { 196 /* Header already set, fetch hlen from there */ 197 hlen = ip->ip_hl << 2; 198 } 199 200 dst = (struct sockaddr_in *)&ro->ro_dst; 201again: 202 ia = NULL; 203 /* 204 * If there is a cached route, 205 * check that it is to the same destination 206 * and is still up. If not, free it and try again. 207 * The address family should also be checked in case of sharing the 208 * cache with IPv6. 209 */ 210 rte = ro->ro_rt; 211 if (rte && ((rte->rt_flags & RTF_UP) == 0 || 212 rte->rt_ifp == NULL || 213 !RT_LINK_IS_UP(rte->rt_ifp) || 214 dst->sin_family != AF_INET || 215 dst->sin_addr.s_addr != ip->ip_dst.s_addr)) { 216 RO_RTFREE(ro); 217 ro->ro_lle = NULL; 218 rte = NULL; 219 } 220#ifdef IPFIREWALL_FORWARD 221 if (rte == NULL && fwd_tag == NULL) { 222#else 223 if (rte == NULL) { 224#endif 225 bzero(dst, sizeof(*dst)); 226 dst->sin_family = AF_INET; 227 dst->sin_len = sizeof(*dst); 228 dst->sin_addr = ip->ip_dst; 229 } 230 /* 231 * If routing to interface only, short circuit routing lookup. 232 * The use of an all-ones broadcast address implies this; an 233 * interface is specified by the broadcast address of an interface, 234 * or the destination address of a ptp interface. 235 */ 236 if (flags & IP_SENDONES) { 237 if ((ia = ifatoia(ifa_ifwithbroadaddr(sintosa(dst)))) == NULL && 238 (ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL) { 239 IPSTAT_INC(ips_noroute); 240 error = ENETUNREACH; 241 goto bad; 242 } 243 ip->ip_dst.s_addr = INADDR_BROADCAST; 244 dst->sin_addr = ip->ip_dst; 245 ifp = ia->ia_ifp; 246 ip->ip_ttl = 1; 247 isbroadcast = 1; 248 } else if (flags & IP_ROUTETOIF) { 249 if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL && 250 (ia = ifatoia(ifa_ifwithnet(sintosa(dst), 0))) == NULL) { 251 IPSTAT_INC(ips_noroute); 252 error = ENETUNREACH; 253 goto bad; 254 } 255 ifp = ia->ia_ifp; 256 ip->ip_ttl = 1; 257 isbroadcast = in_broadcast(dst->sin_addr, ifp); 258 } else if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) && 259 imo != NULL && imo->imo_multicast_ifp != NULL) { 260 /* 261 * Bypass the normal routing lookup for multicast 262 * packets if the interface is specified. 263 */ 264 ifp = imo->imo_multicast_ifp; 265 IFP_TO_IA(ifp, ia); 266 isbroadcast = 0; /* fool gcc */ 267 } else { 268 /* 269 * We want to do any cloning requested by the link layer, 270 * as this is probably required in all cases for correct 271 * operation (as it is for ARP). 272 */ 273 if (rte == NULL) { 274#ifdef RADIX_MPATH 275 rtalloc_mpath_fib(ro, 276 ntohl(ip->ip_src.s_addr ^ ip->ip_dst.s_addr), 277 inp ? inp->inp_inc.inc_fibnum : M_GETFIB(m)); 278#else 279 in_rtalloc_ign(ro, 0, 280 inp ? inp->inp_inc.inc_fibnum : M_GETFIB(m)); 281#endif 282 rte = ro->ro_rt; 283 } 284 if (rte == NULL || 285 rte->rt_ifp == NULL || 286 !RT_LINK_IS_UP(rte->rt_ifp)) { 287#ifdef IPSEC 288 /* 289 * There is no route for this packet, but it is 290 * possible that a matching SPD entry exists. 291 */ 292 no_route_but_check_spd = 1; 293 mtu = 0; /* Silence GCC warning. */ 294 goto sendit; 295#endif 296 IPSTAT_INC(ips_noroute); 297 error = EHOSTUNREACH; 298 goto bad; 299 } 300 ia = ifatoia(rte->rt_ifa); 301 ifa_ref(&ia->ia_ifa); 302 ifp = rte->rt_ifp; 303 rte->rt_rmx.rmx_pksent++; 304 if (rte->rt_flags & RTF_GATEWAY) 305 dst = (struct sockaddr_in *)rte->rt_gateway; 306 if (rte->rt_flags & RTF_HOST) 307 isbroadcast = (rte->rt_flags & RTF_BROADCAST); 308 else 309 isbroadcast = in_broadcast(dst->sin_addr, ifp); 310 } 311 /* 312 * Calculate MTU. If we have a route that is up, use that, 313 * otherwise use the interface's MTU. 314 */ 315 if (rte != NULL && (rte->rt_flags & (RTF_UP|RTF_HOST))) { 316 /* 317 * This case can happen if the user changed the MTU 318 * of an interface after enabling IP on it. Because 319 * most netifs don't keep track of routes pointing to 320 * them, there is no way for one to update all its 321 * routes when the MTU is changed. 322 */ 323 if (rte->rt_rmx.rmx_mtu > ifp->if_mtu) 324 rte->rt_rmx.rmx_mtu = ifp->if_mtu; 325 mtu = rte->rt_rmx.rmx_mtu; 326 } else { 327 mtu = ifp->if_mtu; 328 } 329 /* Catch a possible divide by zero later. */ 330 KASSERT(mtu > 0, ("%s: mtu %d <= 0, rte=%p (rt_flags=0x%08x) ifp=%p", 331 __func__, mtu, rte, (rte != NULL) ? rte->rt_flags : 0, ifp)); 332 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) { 333 m->m_flags |= M_MCAST; 334 /* 335 * IP destination address is multicast. Make sure "dst" 336 * still points to the address in "ro". (It may have been 337 * changed to point to a gateway address, above.) 338 */ 339 dst = (struct sockaddr_in *)&ro->ro_dst; 340 /* 341 * See if the caller provided any multicast options 342 */ 343 if (imo != NULL) { 344 ip->ip_ttl = imo->imo_multicast_ttl; 345 if (imo->imo_multicast_vif != -1) 346 ip->ip_src.s_addr = 347 ip_mcast_src ? 348 ip_mcast_src(imo->imo_multicast_vif) : 349 INADDR_ANY; 350 } else 351 ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL; 352 /* 353 * Confirm that the outgoing interface supports multicast. 354 */ 355 if ((imo == NULL) || (imo->imo_multicast_vif == -1)) { 356 if ((ifp->if_flags & IFF_MULTICAST) == 0) { 357 IPSTAT_INC(ips_noroute); 358 error = ENETUNREACH; 359 goto bad; 360 } 361 } 362 /* 363 * If source address not specified yet, use address 364 * of outgoing interface. 365 */ 366 if (ip->ip_src.s_addr == INADDR_ANY) { 367 /* Interface may have no addresses. */ 368 if (ia != NULL) 369 ip->ip_src = IA_SIN(ia)->sin_addr; 370 } 371 372 if ((imo == NULL && in_mcast_loop) || 373 (imo && imo->imo_multicast_loop)) { 374 /* 375 * Loop back multicast datagram if not expressly 376 * forbidden to do so, even if we are not a member 377 * of the group; ip_input() will filter it later, 378 * thus deferring a hash lookup and mutex acquisition 379 * at the expense of a cheap copy using m_copym(). 380 */ 381 ip_mloopback(ifp, m, dst, hlen); 382 } else { 383 /* 384 * If we are acting as a multicast router, perform 385 * multicast forwarding as if the packet had just 386 * arrived on the interface to which we are about 387 * to send. The multicast forwarding function 388 * recursively calls this function, using the 389 * IP_FORWARDING flag to prevent infinite recursion. 390 * 391 * Multicasts that are looped back by ip_mloopback(), 392 * above, will be forwarded by the ip_input() routine, 393 * if necessary. 394 */ 395 if (V_ip_mrouter && (flags & IP_FORWARDING) == 0) { 396 /* 397 * If rsvp daemon is not running, do not 398 * set ip_moptions. This ensures that the packet 399 * is multicast and not just sent down one link 400 * as prescribed by rsvpd. 401 */ 402 if (!V_rsvp_on) 403 imo = NULL; 404 if (ip_mforward && 405 ip_mforward(ip, ifp, m, imo) != 0) { 406 m_freem(m); 407 goto done; 408 } 409 } 410 } 411 412 /* 413 * Multicasts with a time-to-live of zero may be looped- 414 * back, above, but must not be transmitted on a network. 415 * Also, multicasts addressed to the loopback interface 416 * are not sent -- the above call to ip_mloopback() will 417 * loop back a copy. ip_input() will drop the copy if 418 * this host does not belong to the destination group on 419 * the loopback interface. 420 */ 421 if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) { 422 m_freem(m); 423 goto done; 424 } 425 426 goto sendit; 427 } 428 429 /* 430 * If the source address is not specified yet, use the address 431 * of the outoing interface. 432 */ 433 if (ip->ip_src.s_addr == INADDR_ANY) { 434 /* Interface may have no addresses. */ 435 if (ia != NULL) { 436 ip->ip_src = IA_SIN(ia)->sin_addr; 437 } 438 } 439 440 /* 441 * Verify that we have any chance at all of being able to queue the 442 * packet or packet fragments, unless ALTQ is enabled on the given 443 * interface in which case packetdrop should be done by queueing. 444 */ 445 n = ip->ip_len / mtu + 1; /* how many fragments ? */ 446 if ( 447#ifdef ALTQ 448 (!ALTQ_IS_ENABLED(&ifp->if_snd)) && 449#endif /* ALTQ */ 450 (ifp->if_snd.ifq_len + n) >= ifp->if_snd.ifq_maxlen ) { 451 error = ENOBUFS; 452 IPSTAT_INC(ips_odropped); 453 ifp->if_snd.ifq_drops += n; 454 goto bad; 455 } 456 457 /* 458 * Look for broadcast address and 459 * verify user is allowed to send 460 * such a packet. 461 */ 462 if (isbroadcast) { 463 if ((ifp->if_flags & IFF_BROADCAST) == 0) { 464 error = EADDRNOTAVAIL; 465 goto bad; 466 } 467 if ((flags & IP_ALLOWBROADCAST) == 0) { 468 error = EACCES; 469 goto bad; 470 } 471 /* don't allow broadcast messages to be fragmented */ 472 if (ip->ip_len > mtu) { 473 error = EMSGSIZE; 474 goto bad; 475 } 476 m->m_flags |= M_BCAST; 477 } else { 478 m->m_flags &= ~M_BCAST; 479 } 480 481sendit: 482#ifdef IPSEC 483 switch(ip_ipsec_output(&m, inp, &flags, &error)) { 484 case 1: 485 goto bad; 486 case -1: 487 goto done; 488 case 0: 489 default: 490 break; /* Continue with packet processing. */ 491 } 492 /* 493 * Check if there was a route for this packet; return error if not. 494 */ 495 if (no_route_but_check_spd) { 496 IPSTAT_INC(ips_noroute); 497 error = EHOSTUNREACH; 498 goto bad; 499 } 500 /* Update variables that are affected by ipsec4_output(). */ 501 ip = mtod(m, struct ip *); 502 hlen = ip->ip_hl << 2; 503#endif /* IPSEC */ 504 505 /* 506 * To network byte order. pfil(9) hooks and ip_fragment() expect this. 507 */ 508 ip->ip_len = htons(ip->ip_len); 509 ip->ip_off = htons(ip->ip_off); 510 511 /* Jump over all PFIL processing if hooks are not active. */ 512 if (!PFIL_HOOKED(&V_inet_pfil_hook)) 513 goto passout; 514 515 /* Run through list of hooks for output packets. */ 516 odst.s_addr = ip->ip_dst.s_addr; 517 error = pfil_run_hooks(&V_inet_pfil_hook, &m, ifp, PFIL_OUT, inp); 518 if (error != 0 || m == NULL) 519 goto done; 520 521 ip = mtod(m, struct ip *); 522 523 /* See if destination IP address was changed by packet filter. */ 524 if (odst.s_addr != ip->ip_dst.s_addr) { 525 m->m_flags |= M_SKIP_FIREWALL; 526 /* If destination is now ourself drop to ip_input(). */ 527 if (in_localip(ip->ip_dst)) { 528 m->m_flags |= M_FASTFWD_OURS; 529 if (m->m_pkthdr.rcvif == NULL) 530 m->m_pkthdr.rcvif = V_loif; 531 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 532 m->m_pkthdr.csum_flags |= 533 CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 534 m->m_pkthdr.csum_data = 0xffff; 535 } 536 m->m_pkthdr.csum_flags |= 537 CSUM_IP_CHECKED | CSUM_IP_VALID; 538#ifdef SCTP 539 if (m->m_pkthdr.csum_flags & CSUM_SCTP) 540 m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID; 541#endif 542 error = netisr_queue(NETISR_IP, m); 543 goto done; 544 } else { 545 if (ia != NULL) 546 ifa_free(&ia->ia_ifa); 547 ip->ip_len = ntohs(ip->ip_len); 548 ip->ip_off = ntohs(ip->ip_off); 549 goto again; /* Redo the routing table lookup. */ 550 } 551 } 552 553#ifdef IPFIREWALL_FORWARD 554 /* See if local, if yes, send it to netisr with IP_FASTFWD_OURS. */ 555 if (m->m_flags & M_FASTFWD_OURS) { 556 if (m->m_pkthdr.rcvif == NULL) 557 m->m_pkthdr.rcvif = V_loif; 558 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 559 m->m_pkthdr.csum_flags |= 560 CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 561 m->m_pkthdr.csum_data = 0xffff; 562 } 563#ifdef SCTP 564 if (m->m_pkthdr.csum_flags & CSUM_SCTP) 565 m->m_pkthdr.csum_flags |= CSUM_SCTP_VALID; 566#endif 567 m->m_pkthdr.csum_flags |= 568 CSUM_IP_CHECKED | CSUM_IP_VALID; 569 570 error = netisr_queue(NETISR_IP, m); 571 goto done; 572 } 573 /* Or forward to some other address? */ 574 fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 575 if (fwd_tag) { 576 dst = (struct sockaddr_in *)&ro->ro_dst; 577 bcopy((fwd_tag+1), dst, sizeof(struct sockaddr_in)); 578 m->m_flags |= M_SKIP_FIREWALL; 579 m_tag_delete(m, fwd_tag); 580 if (ia != NULL) 581 ifa_free(&ia->ia_ifa); 582 ip->ip_len = ntohs(ip->ip_len); 583 ip->ip_off = ntohs(ip->ip_off); 584 goto again; 585 } 586#endif /* IPFIREWALL_FORWARD */ 587 588passout: 589 ip_len = ntohs(ip->ip_len); 590 ip_off = ntohs(ip->ip_off); 591 592 /* 127/8 must not appear on wire - RFC1122. */ 593 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 594 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 595 if ((ifp->if_flags & IFF_LOOPBACK) == 0) { 596 IPSTAT_INC(ips_badaddr); 597 error = EADDRNOTAVAIL; 598 goto bad; 599 } 600 } 601 602 m->m_pkthdr.csum_flags |= CSUM_IP; 603 sw_csum = m->m_pkthdr.csum_flags & ~ifp->if_hwassist; 604 if (sw_csum & CSUM_DELAY_DATA) { 605 in_delayed_cksum(m); 606 sw_csum &= ~CSUM_DELAY_DATA; 607 } 608#ifdef SCTP 609 if (sw_csum & CSUM_SCTP) { 610 sctp_delayed_cksum(m, (uint32_t)(ip->ip_hl << 2)); 611 sw_csum &= ~CSUM_SCTP; 612 } 613#endif 614 m->m_pkthdr.csum_flags &= ifp->if_hwassist; 615 616 /* 617 * If small enough for interface, or the interface will take 618 * care of the fragmentation for us, we can just send directly. 619 */ 620 if (ip_len <= mtu || 621 (m->m_pkthdr.csum_flags & ifp->if_hwassist & CSUM_TSO) != 0 || 622 ((ip_off & IP_DF) == 0 && (ifp->if_hwassist & CSUM_FRAGMENT))) { 623 ip->ip_sum = 0; 624 if (sw_csum & CSUM_DELAY_IP) 625 ip->ip_sum = in_cksum(m, hlen); 626 627 /* 628 * Record statistics for this interface address. 629 * With CSUM_TSO the byte/packet count will be slightly 630 * incorrect because we count the IP+TCP headers only 631 * once instead of for every generated packet. 632 */ 633 if (!(flags & IP_FORWARDING) && ia) { 634 if (m->m_pkthdr.csum_flags & CSUM_TSO) 635 ia->ia_ifa.if_opackets += 636 m->m_pkthdr.len / m->m_pkthdr.tso_segsz; 637 else 638 ia->ia_ifa.if_opackets++; 639 ia->ia_ifa.if_obytes += m->m_pkthdr.len; 640 } 641#ifdef MBUF_STRESS_TEST 642 if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size) 643 m = m_fragment(m, M_DONTWAIT, mbuf_frag_size); 644#endif 645 /* 646 * Reset layer specific mbuf flags 647 * to avoid confusing lower layers. 648 */ 649 m->m_flags &= ~(M_PROTOFLAGS); 650 error = (*ifp->if_output)(ifp, m, 651 (struct sockaddr *)dst, ro); 652 goto done; 653 } 654 655 /* Balk when DF bit is set or the interface didn't support TSO. */ 656 if ((ip_off & IP_DF) || (m->m_pkthdr.csum_flags & CSUM_TSO)) { 657 error = EMSGSIZE; 658 IPSTAT_INC(ips_cantfrag); 659 goto bad; 660 } 661 662 /* 663 * Too large for interface; fragment if possible. If successful, 664 * on return, m will point to a list of packets to be sent. 665 */ 666 error = ip_fragment(ip, &m, mtu, ifp->if_hwassist, sw_csum); 667 if (error) 668 goto bad; 669 for (; m; m = m0) { 670 m0 = m->m_nextpkt; 671 m->m_nextpkt = 0; 672 if (error == 0) { 673 /* Record statistics for this interface address. */ 674 if (ia != NULL) { 675 ia->ia_ifa.if_opackets++; 676 ia->ia_ifa.if_obytes += m->m_pkthdr.len; 677 } 678 /* 679 * Reset layer specific mbuf flags 680 * to avoid confusing upper layers. 681 */ 682 m->m_flags &= ~(M_PROTOFLAGS); 683 684 error = (*ifp->if_output)(ifp, m, 685 (struct sockaddr *)dst, ro); 686 } else 687 m_freem(m); 688 } 689 690 if (error == 0) 691 IPSTAT_INC(ips_fragmented); 692 693done: 694 if (ro == &iproute) 695 RO_RTFREE(ro); 696 if (ia != NULL) 697 ifa_free(&ia->ia_ifa); 698 return (error); 699bad: 700 m_freem(m); 701 goto done; 702} 703 704/* 705 * Create a chain of fragments which fit the given mtu. m_frag points to the 706 * mbuf to be fragmented; on return it points to the chain with the fragments. 707 * Return 0 if no error. If error, m_frag may contain a partially built 708 * chain of fragments that should be freed by the caller. 709 * 710 * if_hwassist_flags is the hw offload capabilities (see if_data.ifi_hwassist) 711 * sw_csum contains the delayed checksums flags (e.g., CSUM_DELAY_IP). 712 */ 713int 714ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu, 715 u_long if_hwassist_flags, int sw_csum) 716{ 717 int error = 0; 718 int hlen = ip->ip_hl << 2; 719 int len = (mtu - hlen) & ~7; /* size of payload in each fragment */ 720 int off; 721 struct mbuf *m0 = *m_frag; /* the original packet */ 722 int firstlen; 723 struct mbuf **mnext; 724 int nfrags; 725 uint16_t ip_len, ip_off; 726 727 ip_len = ntohs(ip->ip_len); 728 ip_off = ntohs(ip->ip_off); 729 730 if (ip_off & IP_DF) { /* Fragmentation not allowed */ 731 IPSTAT_INC(ips_cantfrag); 732 return EMSGSIZE; 733 } 734 735 /* 736 * Must be able to put at least 8 bytes per fragment. 737 */ 738 if (len < 8) 739 return EMSGSIZE; 740 741 /* 742 * If the interface will not calculate checksums on 743 * fragmented packets, then do it here. 744 */ 745 if (m0->m_pkthdr.csum_flags & CSUM_DELAY_DATA && 746 (if_hwassist_flags & CSUM_IP_FRAGS) == 0) { 747 in_delayed_cksum(m0); 748 m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 749 } 750#ifdef SCTP 751 if (m0->m_pkthdr.csum_flags & CSUM_SCTP && 752 (if_hwassist_flags & CSUM_IP_FRAGS) == 0) { 753 sctp_delayed_cksum(m0, hlen); 754 m0->m_pkthdr.csum_flags &= ~CSUM_SCTP; 755 } 756#endif 757 if (len > PAGE_SIZE) { 758 /* 759 * Fragment large datagrams such that each segment 760 * contains a multiple of PAGE_SIZE amount of data, 761 * plus headers. This enables a receiver to perform 762 * page-flipping zero-copy optimizations. 763 * 764 * XXX When does this help given that sender and receiver 765 * could have different page sizes, and also mtu could 766 * be less than the receiver's page size ? 767 */ 768 int newlen; 769 struct mbuf *m; 770 771 for (m = m0, off = 0; m && (off+m->m_len) <= mtu; m = m->m_next) 772 off += m->m_len; 773 774 /* 775 * firstlen (off - hlen) must be aligned on an 776 * 8-byte boundary 777 */ 778 if (off < hlen) 779 goto smart_frag_failure; 780 off = ((off - hlen) & ~7) + hlen; 781 newlen = (~PAGE_MASK) & mtu; 782 if ((newlen + sizeof (struct ip)) > mtu) { 783 /* we failed, go back the default */ 784smart_frag_failure: 785 newlen = len; 786 off = hlen + len; 787 } 788 len = newlen; 789 790 } else { 791 off = hlen + len; 792 } 793 794 firstlen = off - hlen; 795 mnext = &m0->m_nextpkt; /* pointer to next packet */ 796 797 /* 798 * Loop through length of segment after first fragment, 799 * make new header and copy data of each part and link onto chain. 800 * Here, m0 is the original packet, m is the fragment being created. 801 * The fragments are linked off the m_nextpkt of the original 802 * packet, which after processing serves as the first fragment. 803 */ 804 for (nfrags = 1; off < ip_len; off += len, nfrags++) { 805 struct ip *mhip; /* ip header on the fragment */ 806 struct mbuf *m; 807 int mhlen = sizeof (struct ip); 808 809 MGETHDR(m, M_DONTWAIT, MT_DATA); 810 if (m == NULL) { 811 error = ENOBUFS; 812 IPSTAT_INC(ips_odropped); 813 goto done; 814 } 815 m->m_flags |= (m0->m_flags & M_MCAST) | M_FRAG; 816 /* 817 * In the first mbuf, leave room for the link header, then 818 * copy the original IP header including options. The payload 819 * goes into an additional mbuf chain returned by m_copym(). 820 */ 821 m->m_data += max_linkhdr; 822 mhip = mtod(m, struct ip *); 823 *mhip = *ip; 824 if (hlen > sizeof (struct ip)) { 825 mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip); 826 mhip->ip_v = IPVERSION; 827 mhip->ip_hl = mhlen >> 2; 828 } 829 m->m_len = mhlen; 830 /* XXX do we need to add ip_off below ? */ 831 mhip->ip_off = ((off - hlen) >> 3) + ip_off; 832 if (off + len >= ip_len) { /* last fragment */ 833 len = ip_len - off; 834 m->m_flags |= M_LASTFRAG; 835 } else 836 mhip->ip_off |= IP_MF; 837 mhip->ip_len = htons((u_short)(len + mhlen)); 838 m->m_next = m_copym(m0, off, len, M_DONTWAIT); 839 if (m->m_next == NULL) { /* copy failed */ 840 m_free(m); 841 error = ENOBUFS; /* ??? */ 842 IPSTAT_INC(ips_odropped); 843 goto done; 844 } 845 m->m_pkthdr.len = mhlen + len; 846 m->m_pkthdr.rcvif = NULL; 847#ifdef MAC 848 mac_netinet_fragment(m0, m); 849#endif 850 m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags; 851 mhip->ip_off = htons(mhip->ip_off); 852 mhip->ip_sum = 0; 853 if (sw_csum & CSUM_DELAY_IP) 854 mhip->ip_sum = in_cksum(m, mhlen); 855 *mnext = m; 856 mnext = &m->m_nextpkt; 857 } 858 IPSTAT_ADD(ips_ofragments, nfrags); 859 860 /* set first marker for fragment chain */ 861 m0->m_flags |= M_FIRSTFRAG | M_FRAG; 862 m0->m_pkthdr.csum_data = nfrags; 863 864 /* 865 * Update first fragment by trimming what's been copied out 866 * and updating header. 867 */ 868 m_adj(m0, hlen + firstlen - ip_len); 869 m0->m_pkthdr.len = hlen + firstlen; 870 ip->ip_len = htons((u_short)m0->m_pkthdr.len); 871 ip->ip_off = htons(ip_off | IP_MF); 872 ip->ip_sum = 0; 873 if (sw_csum & CSUM_DELAY_IP) 874 ip->ip_sum = in_cksum(m0, hlen); 875 876done: 877 *m_frag = m0; 878 return error; 879} 880 881void 882in_delayed_cksum(struct mbuf *m) 883{ 884 struct ip *ip; 885 uint16_t csum, offset, ip_len; 886 887 ip = mtod(m, struct ip *); 888 offset = ip->ip_hl << 2 ; 889 ip_len = ntohs(ip->ip_len); 890 csum = in_cksum_skip(m, ip_len, offset); 891 if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0) 892 csum = 0xffff; 893 offset += m->m_pkthdr.csum_data; /* checksum offset */ 894 895 if (offset + sizeof(u_short) > m->m_len) { 896 printf("delayed m_pullup, m->len: %d off: %d p: %d\n", 897 m->m_len, offset, ip->ip_p); 898 /* 899 * XXX 900 * this shouldn't happen, but if it does, the 901 * correct behavior may be to insert the checksum 902 * in the appropriate next mbuf in the chain. 903 */ 904 return; 905 } 906 *(u_short *)(m->m_data + offset) = csum; 907} 908 909/* 910 * IP socket option processing. 911 */ 912int 913ip_ctloutput(struct socket *so, struct sockopt *sopt) 914{ 915 struct inpcb *inp = sotoinpcb(so); 916 int error, optval; 917 918 error = optval = 0; 919 if (sopt->sopt_level != IPPROTO_IP) { 920 error = EINVAL; 921 922 if (sopt->sopt_level == SOL_SOCKET && 923 sopt->sopt_dir == SOPT_SET) { 924 switch (sopt->sopt_name) { 925 case SO_REUSEADDR: 926 INP_WLOCK(inp); 927 if (IN_MULTICAST(ntohl(inp->inp_laddr.s_addr))) { 928 if ((so->so_options & 929 (SO_REUSEADDR | SO_REUSEPORT)) != 0) 930 inp->inp_flags2 |= INP_REUSEPORT; 931 else 932 inp->inp_flags2 &= ~INP_REUSEPORT; 933 } 934 INP_WUNLOCK(inp); 935 error = 0; 936 break; 937 case SO_REUSEPORT: 938 INP_WLOCK(inp); 939 if ((so->so_options & SO_REUSEPORT) != 0) 940 inp->inp_flags2 |= INP_REUSEPORT; 941 else 942 inp->inp_flags2 &= ~INP_REUSEPORT; 943 INP_WUNLOCK(inp); 944 error = 0; 945 break; 946 case SO_SETFIB: 947 INP_WLOCK(inp); 948 inp->inp_inc.inc_fibnum = so->so_fibnum; 949 INP_WUNLOCK(inp); 950 error = 0; 951 break; 952 default: 953 break; 954 } 955 } 956 return (error); 957 } 958 959 switch (sopt->sopt_dir) { 960 case SOPT_SET: 961 switch (sopt->sopt_name) { 962 case IP_OPTIONS: 963#ifdef notyet 964 case IP_RETOPTS: 965#endif 966 { 967 struct mbuf *m; 968 if (sopt->sopt_valsize > MLEN) { 969 error = EMSGSIZE; 970 break; 971 } 972 MGET(m, sopt->sopt_td ? M_WAIT : M_DONTWAIT, MT_DATA); 973 if (m == NULL) { 974 error = ENOBUFS; 975 break; 976 } 977 m->m_len = sopt->sopt_valsize; 978 error = sooptcopyin(sopt, mtod(m, char *), m->m_len, 979 m->m_len); 980 if (error) { 981 m_free(m); 982 break; 983 } 984 INP_WLOCK(inp); 985 error = ip_pcbopts(inp, sopt->sopt_name, m); 986 INP_WUNLOCK(inp); 987 return (error); 988 } 989 990 case IP_BINDANY: 991 if (sopt->sopt_td != NULL) { 992 error = priv_check(sopt->sopt_td, 993 PRIV_NETINET_BINDANY); 994 if (error) 995 break; 996 } 997 /* FALLTHROUGH */ 998 case IP_TOS: 999 case IP_TTL: 1000 case IP_MINTTL: 1001 case IP_RECVOPTS: 1002 case IP_RECVRETOPTS: 1003 case IP_RECVDSTADDR: 1004 case IP_RECVTTL: 1005 case IP_RECVIF: 1006 case IP_FAITH: 1007 case IP_ONESBCAST: 1008 case IP_DONTFRAG: 1009 case IP_RECVTOS: 1010 error = sooptcopyin(sopt, &optval, sizeof optval, 1011 sizeof optval); 1012 if (error) 1013 break; 1014 1015 switch (sopt->sopt_name) { 1016 case IP_TOS: 1017 inp->inp_ip_tos = optval; 1018 break; 1019 1020 case IP_TTL: 1021 inp->inp_ip_ttl = optval; 1022 break; 1023 1024 case IP_MINTTL: 1025 if (optval >= 0 && optval <= MAXTTL) 1026 inp->inp_ip_minttl = optval; 1027 else 1028 error = EINVAL; 1029 break; 1030 1031#define OPTSET(bit) do { \ 1032 INP_WLOCK(inp); \ 1033 if (optval) \ 1034 inp->inp_flags |= bit; \ 1035 else \ 1036 inp->inp_flags &= ~bit; \ 1037 INP_WUNLOCK(inp); \ 1038} while (0) 1039 1040 case IP_RECVOPTS: 1041 OPTSET(INP_RECVOPTS); 1042 break; 1043 1044 case IP_RECVRETOPTS: 1045 OPTSET(INP_RECVRETOPTS); 1046 break; 1047 1048 case IP_RECVDSTADDR: 1049 OPTSET(INP_RECVDSTADDR); 1050 break; 1051 1052 case IP_RECVTTL: 1053 OPTSET(INP_RECVTTL); 1054 break; 1055 1056 case IP_RECVIF: 1057 OPTSET(INP_RECVIF); 1058 break; 1059 1060 case IP_FAITH: 1061 OPTSET(INP_FAITH); 1062 break; 1063 1064 case IP_ONESBCAST: 1065 OPTSET(INP_ONESBCAST); 1066 break; 1067 case IP_DONTFRAG: 1068 OPTSET(INP_DONTFRAG); 1069 break; 1070 case IP_BINDANY: 1071 OPTSET(INP_BINDANY); 1072 break; 1073 case IP_RECVTOS: 1074 OPTSET(INP_RECVTOS); 1075 break; 1076 } 1077 break; 1078#undef OPTSET 1079 1080 /* 1081 * Multicast socket options are processed by the in_mcast 1082 * module. 1083 */ 1084 case IP_MULTICAST_IF: 1085 case IP_MULTICAST_VIF: 1086 case IP_MULTICAST_TTL: 1087 case IP_MULTICAST_LOOP: 1088 case IP_ADD_MEMBERSHIP: 1089 case IP_DROP_MEMBERSHIP: 1090 case IP_ADD_SOURCE_MEMBERSHIP: 1091 case IP_DROP_SOURCE_MEMBERSHIP: 1092 case IP_BLOCK_SOURCE: 1093 case IP_UNBLOCK_SOURCE: 1094 case IP_MSFILTER: 1095 case MCAST_JOIN_GROUP: 1096 case MCAST_LEAVE_GROUP: 1097 case MCAST_JOIN_SOURCE_GROUP: 1098 case MCAST_LEAVE_SOURCE_GROUP: 1099 case MCAST_BLOCK_SOURCE: 1100 case MCAST_UNBLOCK_SOURCE: 1101 error = inp_setmoptions(inp, sopt); 1102 break; 1103 1104 case IP_PORTRANGE: 1105 error = sooptcopyin(sopt, &optval, sizeof optval, 1106 sizeof optval); 1107 if (error) 1108 break; 1109 1110 INP_WLOCK(inp); 1111 switch (optval) { 1112 case IP_PORTRANGE_DEFAULT: 1113 inp->inp_flags &= ~(INP_LOWPORT); 1114 inp->inp_flags &= ~(INP_HIGHPORT); 1115 break; 1116 1117 case IP_PORTRANGE_HIGH: 1118 inp->inp_flags &= ~(INP_LOWPORT); 1119 inp->inp_flags |= INP_HIGHPORT; 1120 break; 1121 1122 case IP_PORTRANGE_LOW: 1123 inp->inp_flags &= ~(INP_HIGHPORT); 1124 inp->inp_flags |= INP_LOWPORT; 1125 break; 1126 1127 default: 1128 error = EINVAL; 1129 break; 1130 } 1131 INP_WUNLOCK(inp); 1132 break; 1133 1134#ifdef IPSEC 1135 case IP_IPSEC_POLICY: 1136 { 1137 caddr_t req; 1138 struct mbuf *m; 1139 1140 if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */ 1141 break; 1142 if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */ 1143 break; 1144 req = mtod(m, caddr_t); 1145 error = ipsec_set_policy(inp, sopt->sopt_name, req, 1146 m->m_len, (sopt->sopt_td != NULL) ? 1147 sopt->sopt_td->td_ucred : NULL); 1148 m_freem(m); 1149 break; 1150 } 1151#endif /* IPSEC */ 1152 1153 default: 1154 error = ENOPROTOOPT; 1155 break; 1156 } 1157 break; 1158 1159 case SOPT_GET: 1160 switch (sopt->sopt_name) { 1161 case IP_OPTIONS: 1162 case IP_RETOPTS: 1163 if (inp->inp_options) 1164 error = sooptcopyout(sopt, 1165 mtod(inp->inp_options, 1166 char *), 1167 inp->inp_options->m_len); 1168 else 1169 sopt->sopt_valsize = 0; 1170 break; 1171 1172 case IP_TOS: 1173 case IP_TTL: 1174 case IP_MINTTL: 1175 case IP_RECVOPTS: 1176 case IP_RECVRETOPTS: 1177 case IP_RECVDSTADDR: 1178 case IP_RECVTTL: 1179 case IP_RECVIF: 1180 case IP_PORTRANGE: 1181 case IP_FAITH: 1182 case IP_ONESBCAST: 1183 case IP_DONTFRAG: 1184 case IP_BINDANY: 1185 case IP_RECVTOS: 1186 switch (sopt->sopt_name) { 1187 1188 case IP_TOS: 1189 optval = inp->inp_ip_tos; 1190 break; 1191 1192 case IP_TTL: 1193 optval = inp->inp_ip_ttl; 1194 break; 1195 1196 case IP_MINTTL: 1197 optval = inp->inp_ip_minttl; 1198 break; 1199 1200#define OPTBIT(bit) (inp->inp_flags & bit ? 1 : 0) 1201 1202 case IP_RECVOPTS: 1203 optval = OPTBIT(INP_RECVOPTS); 1204 break; 1205 1206 case IP_RECVRETOPTS: 1207 optval = OPTBIT(INP_RECVRETOPTS); 1208 break; 1209 1210 case IP_RECVDSTADDR: 1211 optval = OPTBIT(INP_RECVDSTADDR); 1212 break; 1213 1214 case IP_RECVTTL: 1215 optval = OPTBIT(INP_RECVTTL); 1216 break; 1217 1218 case IP_RECVIF: 1219 optval = OPTBIT(INP_RECVIF); 1220 break; 1221 1222 case IP_PORTRANGE: 1223 if (inp->inp_flags & INP_HIGHPORT) 1224 optval = IP_PORTRANGE_HIGH; 1225 else if (inp->inp_flags & INP_LOWPORT) 1226 optval = IP_PORTRANGE_LOW; 1227 else 1228 optval = 0; 1229 break; 1230 1231 case IP_FAITH: 1232 optval = OPTBIT(INP_FAITH); 1233 break; 1234 1235 case IP_ONESBCAST: 1236 optval = OPTBIT(INP_ONESBCAST); 1237 break; 1238 case IP_DONTFRAG: 1239 optval = OPTBIT(INP_DONTFRAG); 1240 break; 1241 case IP_BINDANY: 1242 optval = OPTBIT(INP_BINDANY); 1243 break; 1244 case IP_RECVTOS: 1245 optval = OPTBIT(INP_RECVTOS); 1246 break; 1247 } 1248 error = sooptcopyout(sopt, &optval, sizeof optval); 1249 break; 1250 1251 /* 1252 * Multicast socket options are processed by the in_mcast 1253 * module. 1254 */ 1255 case IP_MULTICAST_IF: 1256 case IP_MULTICAST_VIF: 1257 case IP_MULTICAST_TTL: 1258 case IP_MULTICAST_LOOP: 1259 case IP_MSFILTER: 1260 error = inp_getmoptions(inp, sopt); 1261 break; 1262 1263#ifdef IPSEC 1264 case IP_IPSEC_POLICY: 1265 { 1266 struct mbuf *m = NULL; 1267 caddr_t req = NULL; 1268 size_t len = 0; 1269 1270 if (m != 0) { 1271 req = mtod(m, caddr_t); 1272 len = m->m_len; 1273 } 1274 error = ipsec_get_policy(sotoinpcb(so), req, len, &m); 1275 if (error == 0) 1276 error = soopt_mcopyout(sopt, m); /* XXX */ 1277 if (error == 0) 1278 m_freem(m); 1279 break; 1280 } 1281#endif /* IPSEC */ 1282 1283 default: 1284 error = ENOPROTOOPT; 1285 break; 1286 } 1287 break; 1288 } 1289 return (error); 1290} 1291 1292/* 1293 * Routine called from ip_output() to loop back a copy of an IP multicast 1294 * packet to the input queue of a specified interface. Note that this 1295 * calls the output routine of the loopback "driver", but with an interface 1296 * pointer that might NOT be a loopback interface -- evil, but easier than 1297 * replicating that code here. 1298 * 1299 * IP header in host byte order. 1300 */ 1301static void 1302ip_mloopback(struct ifnet *ifp, struct mbuf *m, struct sockaddr_in *dst, 1303 int hlen) 1304{ 1305 register struct ip *ip; 1306 struct mbuf *copym; 1307 1308 /* 1309 * Make a deep copy of the packet because we're going to 1310 * modify the pack in order to generate checksums. 1311 */ 1312 copym = m_dup(m, M_DONTWAIT); 1313 if (copym != NULL && (copym->m_flags & M_EXT || copym->m_len < hlen)) 1314 copym = m_pullup(copym, hlen); 1315 if (copym != NULL) { 1316 /* If needed, compute the checksum and mark it as valid. */ 1317 if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { 1318 in_delayed_cksum(copym); 1319 copym->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; 1320 copym->m_pkthdr.csum_flags |= 1321 CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 1322 copym->m_pkthdr.csum_data = 0xffff; 1323 } 1324 /* 1325 * We don't bother to fragment if the IP length is greater 1326 * than the interface's MTU. Can this possibly matter? 1327 */ 1328 ip = mtod(copym, struct ip *); 1329 ip->ip_len = htons(ip->ip_len); 1330 ip->ip_off = htons(ip->ip_off); 1331 ip->ip_sum = 0; 1332 ip->ip_sum = in_cksum(copym, hlen); 1333#if 1 /* XXX */ 1334 if (dst->sin_family != AF_INET) { 1335 printf("ip_mloopback: bad address family %d\n", 1336 dst->sin_family); 1337 dst->sin_family = AF_INET; 1338 } 1339#endif 1340 if_simloop(ifp, copym, dst->sin_family, 0); 1341 } 1342} 1343