ip_fastfwd.c revision 144301
1139823Simp/*- 2122702Sandre * Copyright (c) 2003 Andre Oppermann, Internet Business Solutions AG 3122702Sandre * All rights reserved. 4122702Sandre * 5122702Sandre * Redistribution and use in source and binary forms, with or without 6122702Sandre * modification, are permitted provided that the following conditions 7122702Sandre * are met: 8122702Sandre * 1. Redistributions of source code must retain the above copyright 9122702Sandre * notice, this list of conditions and the following disclaimer. 10122702Sandre * 2. Redistributions in binary form must reproduce the above copyright 11122702Sandre * notice, this list of conditions and the following disclaimer in the 12122702Sandre * documentation and/or other materials provided with the distribution. 13122702Sandre * 3. The name of the author may not be used to endorse or promote 14122702Sandre * products derived from this software without specific prior written 15122702Sandre * permission. 16122702Sandre * 17122702Sandre * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18122702Sandre * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19122702Sandre * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20122702Sandre * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21122702Sandre * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22122702Sandre * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23122702Sandre * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24122702Sandre * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25122702Sandre * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26122702Sandre * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27122702Sandre * SUCH DAMAGE. 28122702Sandre * 29122702Sandre * $FreeBSD: head/sys/netinet/ip_fastfwd.c 144301 2005-03-29 13:43:09Z glebius $ 30122702Sandre */ 31122702Sandre 32122702Sandre/* 33122702Sandre * ip_fastforward gets its speed from processing the forwarded packet to 34122702Sandre * completion (if_output on the other side) without any queues or netisr's. 35122702Sandre * The receiving interface DMAs the packet into memory, the upper half of 36122702Sandre * driver calls ip_fastforward, we do our routing table lookup and directly 37122702Sandre * send it off to the outgoing interface which DMAs the packet to the 38122702Sandre * network card. The only part of the packet we touch with the CPU is the 39122759Sandre * IP header (unless there are complex firewall rules touching other parts 40122759Sandre * of the packet, but that is up to you). We are essentially limited by bus 41122759Sandre * bandwidth and how fast the network card/driver can set up receives and 42122759Sandre * transmits. 43122702Sandre * 44122702Sandre * We handle basic errors, ip header errors, checksum errors, 45122702Sandre * destination unreachable, fragmentation and fragmentation needed and 46122702Sandre * report them via icmp to the sender. 47122702Sandre * 48122702Sandre * Else if something is not pure IPv4 unicast forwarding we fall back to 49122702Sandre * the normal ip_input processing path. We should only be called from 50122702Sandre * interfaces connected to the outside world. 51122702Sandre * 52122702Sandre * Firewalling is fully supported including divert, ipfw fwd and ipfilter 53122702Sandre * ipnat and address rewrite. 54122702Sandre * 55122702Sandre * IPSEC is not supported if this host is a tunnel broker. IPSEC is 56122702Sandre * supported for connections to/from local host. 57122702Sandre * 58122702Sandre * We try to do the least expensive (in CPU ops) checks and operations 59122702Sandre * first to catch junk with as little overhead as possible. 60122702Sandre * 61122702Sandre * We take full advantage of hardware support for ip checksum and 62122702Sandre * fragmentation offloading. 63122702Sandre * 64122702Sandre * We don't do ICMP redirect in the fast forwarding path. I have had my own 65122702Sandre * cases where two core routers with Zebra routing suite would send millions 66122702Sandre * ICMP redirects to connected hosts if the router to dest was not the default 67122702Sandre * gateway. In one case it was filling the routing table of a host with close 68122702Sandre * 300'000 cloned redirect entries until it ran out of kernel memory. However 69122702Sandre * the networking code proved very robust and it didn't crash or went ill 70122702Sandre * otherwise. 71122702Sandre */ 72122702Sandre 73122702Sandre/* 74122702Sandre * Many thanks to Matt Thomas of NetBSD for basic structure of ip_flow.c which 75122702Sandre * is being followed here. 76122702Sandre */ 77122702Sandre 78122702Sandre#include "opt_ipfw.h" 79122702Sandre#include "opt_ipstealth.h" 80122702Sandre 81122702Sandre#include <sys/param.h> 82122702Sandre#include <sys/systm.h> 83122702Sandre#include <sys/kernel.h> 84122702Sandre#include <sys/malloc.h> 85122702Sandre#include <sys/mbuf.h> 86122702Sandre#include <sys/protosw.h> 87122702Sandre#include <sys/socket.h> 88122702Sandre#include <sys/sysctl.h> 89122702Sandre 90122702Sandre#include <net/pfil.h> 91122702Sandre#include <net/if.h> 92122702Sandre#include <net/if_types.h> 93122702Sandre#include <net/if_var.h> 94122702Sandre#include <net/if_dl.h> 95122702Sandre#include <net/route.h> 96122702Sandre 97122702Sandre#include <netinet/in.h> 98122702Sandre#include <netinet/in_systm.h> 99122702Sandre#include <netinet/in_var.h> 100122702Sandre#include <netinet/ip.h> 101122702Sandre#include <netinet/ip_var.h> 102122702Sandre#include <netinet/ip_icmp.h> 103122702Sandre 104122702Sandre#include <machine/in_cksum.h> 105122702Sandre 106122702Sandrestatic int ipfastforward_active = 0; 107122702SandreSYSCTL_INT(_net_inet_ip, OID_AUTO, fastforwarding, CTLFLAG_RW, 108122702Sandre &ipfastforward_active, 0, "Enable fast IP forwarding"); 109122702Sandre 110128872Sandrestatic struct sockaddr_in * 111133497Sandreip_findroute(struct route *ro, struct in_addr dest, struct mbuf *m) 112128872Sandre{ 113128872Sandre struct sockaddr_in *dst; 114128872Sandre struct rtentry *rt; 115128872Sandre 116128872Sandre /* 117128872Sandre * Find route to destination. 118128872Sandre */ 119128872Sandre bzero(ro, sizeof(*ro)); 120128872Sandre dst = (struct sockaddr_in *)&ro->ro_dst; 121128872Sandre dst->sin_family = AF_INET; 122128872Sandre dst->sin_len = sizeof(*dst); 123133497Sandre dst->sin_addr.s_addr = dest.s_addr; 124128872Sandre rtalloc_ign(ro, RTF_CLONING); 125128872Sandre 126128872Sandre /* 127128872Sandre * Route there and interface still up? 128128872Sandre */ 129128872Sandre rt = ro->ro_rt; 130128872Sandre if (rt && (rt->rt_flags & RTF_UP) && 131128872Sandre (rt->rt_ifp->if_flags & IFF_UP) && 132128872Sandre (rt->rt_ifp->if_flags & IFF_RUNNING)) { 133128872Sandre if (rt->rt_flags & RTF_GATEWAY) 134128872Sandre dst = (struct sockaddr_in *)rt->rt_gateway; 135128872Sandre } else { 136128872Sandre ipstat.ips_noroute++; 137128872Sandre ipstat.ips_cantforward++; 138128872Sandre if (rt) 139128872Sandre RTFREE(rt); 140128872Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, NULL); 141128872Sandre return NULL; 142128872Sandre } 143128872Sandre return dst; 144128872Sandre} 145128872Sandre 146122702Sandre/* 147122702Sandre * Try to forward a packet based on the destination address. 148122702Sandre * This is a fast path optimized for the plain forwarding case. 149122702Sandre * If the packet is handled (and consumed) here then we return 1; 150122702Sandre * otherwise 0 is returned and the packet should be delivered 151122702Sandre * to ip_input for full processing. 152122702Sandre */ 153122702Sandreint 154122702Sandreip_fastforward(struct mbuf *m) 155122702Sandre{ 156122702Sandre struct ip *ip; 157122702Sandre struct mbuf *m0 = NULL; 158122702Sandre struct route ro; 159122702Sandre struct sockaddr_in *dst = NULL; 160122702Sandre struct in_ifaddr *ia = NULL; 161122702Sandre struct ifaddr *ifa = NULL; 162128872Sandre struct ifnet *ifp; 163133497Sandre struct in_addr odest, dest; 164128872Sandre u_short sum, ip_len; 165122702Sandre int error = 0; 166133920Sandre int hlen, mtu; 167133920Sandre#ifdef IPFIREWALL_FORWARD 168133920Sandre struct m_tag *fwd_tag; 169133920Sandre#endif 170122702Sandre 171122702Sandre /* 172122702Sandre * Are we active and forwarding packets? 173122702Sandre */ 174122702Sandre if (!ipfastforward_active || !ipforwarding) 175122702Sandre return 0; 176122702Sandre 177122702Sandre M_ASSERTVALID(m); 178122702Sandre M_ASSERTPKTHDR(m); 179122702Sandre 180128872Sandre ro.ro_rt = NULL; 181128872Sandre 182122702Sandre /* 183122702Sandre * Step 1: check for packet drop conditions (and sanity checks) 184122702Sandre */ 185122702Sandre 186122702Sandre /* 187122702Sandre * Is entire packet big enough? 188122702Sandre */ 189122702Sandre if (m->m_pkthdr.len < sizeof(struct ip)) { 190122702Sandre ipstat.ips_tooshort++; 191122702Sandre goto drop; 192122702Sandre } 193122702Sandre 194122702Sandre /* 195122702Sandre * Is first mbuf large enough for ip header and is header present? 196122702Sandre */ 197122702Sandre if (m->m_len < sizeof (struct ip) && 198137302Sandre (m = m_pullup(m, sizeof (struct ip))) == NULL) { 199122702Sandre ipstat.ips_toosmall++; 200137302Sandre return 1; /* mbuf already free'd */ 201122702Sandre } 202122702Sandre 203122702Sandre ip = mtod(m, struct ip *); 204122702Sandre 205122702Sandre /* 206122702Sandre * Is it IPv4? 207122702Sandre */ 208122702Sandre if (ip->ip_v != IPVERSION) { 209122702Sandre ipstat.ips_badvers++; 210122702Sandre goto drop; 211122702Sandre } 212122702Sandre 213122702Sandre /* 214122702Sandre * Is IP header length correct and is it in first mbuf? 215122702Sandre */ 216122702Sandre hlen = ip->ip_hl << 2; 217122702Sandre if (hlen < sizeof(struct ip)) { /* minimum header length */ 218122702Sandre ipstat.ips_badlen++; 219122702Sandre goto drop; 220122702Sandre } 221122702Sandre if (hlen > m->m_len) { 222122702Sandre if ((m = m_pullup(m, hlen)) == 0) { 223122702Sandre ipstat.ips_badhlen++; 224137450Sandre return 1; 225122702Sandre } 226122702Sandre ip = mtod(m, struct ip *); 227122702Sandre } 228122702Sandre 229122702Sandre /* 230122702Sandre * Checksum correct? 231122702Sandre */ 232122702Sandre if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) 233122702Sandre sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 234122702Sandre else { 235122702Sandre if (hlen == sizeof(struct ip)) 236122702Sandre sum = in_cksum_hdr(ip); 237122702Sandre else 238122702Sandre sum = in_cksum(m, hlen); 239122702Sandre } 240122702Sandre if (sum) { 241122702Sandre ipstat.ips_badsum++; 242122702Sandre goto drop; 243122702Sandre } 244136690Sandre 245136690Sandre /* 246136690Sandre * Remeber that we have checked the IP header and found it valid. 247136690Sandre */ 248122702Sandre m->m_pkthdr.csum_flags |= (CSUM_IP_CHECKED | CSUM_IP_VALID); 249122702Sandre 250128872Sandre ip_len = ntohs(ip->ip_len); 251122702Sandre 252122702Sandre /* 253122702Sandre * Is IP length longer than packet we have got? 254122702Sandre */ 255128872Sandre if (m->m_pkthdr.len < ip_len) { 256122702Sandre ipstat.ips_tooshort++; 257122702Sandre goto drop; 258122702Sandre } 259122702Sandre 260122702Sandre /* 261122702Sandre * Is packet longer than IP header tells us? If yes, truncate packet. 262122702Sandre */ 263128872Sandre if (m->m_pkthdr.len > ip_len) { 264122702Sandre if (m->m_len == m->m_pkthdr.len) { 265128872Sandre m->m_len = ip_len; 266128872Sandre m->m_pkthdr.len = ip_len; 267122702Sandre } else 268128872Sandre m_adj(m, ip_len - m->m_pkthdr.len); 269122702Sandre } 270122702Sandre 271122702Sandre /* 272122702Sandre * Is packet from or to 127/8? 273122702Sandre */ 274122702Sandre if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 275122702Sandre (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 276122702Sandre ipstat.ips_badaddr++; 277122702Sandre goto drop; 278122702Sandre } 279122702Sandre 280133480Sandre#ifdef ALTQ 281122702Sandre /* 282133480Sandre * Is packet dropped by traffic conditioner? 283133480Sandre */ 284133480Sandre if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) 285133480Sandre return 1; 286133480Sandre#endif 287133480Sandre 288133480Sandre /* 289122702Sandre * Step 2: fallback conditions to normal ip_input path processing 290122702Sandre */ 291122702Sandre 292122702Sandre /* 293122702Sandre * Only IP packets without options 294122702Sandre */ 295129017Sandre if (ip->ip_hl != (sizeof(struct ip) >> 2)) { 296129017Sandre if (ip_doopts == 1) 297129017Sandre return 0; 298129017Sandre else if (ip_doopts == 2) { 299129017Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_FILTER_PROHIB, 300129017Sandre 0, NULL); 301129017Sandre return 1; 302129017Sandre } 303129017Sandre /* else ignore IP options and continue */ 304129017Sandre } 305122702Sandre 306122702Sandre /* 307122702Sandre * Only unicast IP, not from loopback, no L2 or IP broadcast, 308122702Sandre * no multicast, no INADDR_ANY 309122702Sandre * 310122702Sandre * XXX: Probably some of these checks could be direct drop 311122702Sandre * conditions. However it is not clear whether there are some 312122702Sandre * hacks or obscure behaviours which make it neccessary to 313122702Sandre * let ip_input handle it. We play safe here and let ip_input 314122702Sandre * deal with it until it is proven that we can directly drop it. 315122702Sandre */ 316122702Sandre if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) || 317122702Sandre ntohl(ip->ip_src.s_addr) == (u_long)INADDR_BROADCAST || 318122702Sandre ntohl(ip->ip_dst.s_addr) == (u_long)INADDR_BROADCAST || 319122702Sandre IN_MULTICAST(ntohl(ip->ip_src.s_addr)) || 320122702Sandre IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) || 321122702Sandre ip->ip_dst.s_addr == INADDR_ANY ) 322128872Sandre return 0; 323122702Sandre 324122702Sandre /* 325122702Sandre * Is it for a local address on this host? 326122702Sandre */ 327133497Sandre if (in_localip(ip->ip_dst)) 328133497Sandre return 0; 329122702Sandre 330122702Sandre /* 331122702Sandre * Or is it for a local IP broadcast address on this host? 332122702Sandre */ 333133482Sandre if ((m->m_flags & M_BCAST) && 334133482Sandre (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST)) { 335122702Sandre TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 336122702Sandre if (ifa->ifa_addr->sa_family != AF_INET) 337122702Sandre continue; 338122702Sandre ia = ifatoia(ifa); 339122702Sandre if (ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr) 340128872Sandre return 0; 341122702Sandre if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 342122702Sandre ip->ip_dst.s_addr) 343128872Sandre return 0; 344122702Sandre } 345122702Sandre } 346122702Sandre ipstat.ips_total++; 347122702Sandre 348122702Sandre /* 349122702Sandre * Step 3: incoming packet firewall processing 350122702Sandre */ 351122702Sandre 352128872Sandre /* 353128872Sandre * Convert to host representation 354128872Sandre */ 355128872Sandre ip->ip_len = ntohs(ip->ip_len); 356128872Sandre ip->ip_off = ntohs(ip->ip_off); 357128872Sandre 358133497Sandre odest.s_addr = dest.s_addr = ip->ip_dst.s_addr; 359134383Sandre 360122702Sandre /* 361122702Sandre * Run through list of ipfilter hooks for input packets 362122702Sandre */ 363134383Sandre if (inet_pfil_hook.ph_busy_count == -1) 364134383Sandre goto passin; 365134383Sandre 366135920Smlaier if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, PFIL_IN, NULL) || 367122702Sandre m == NULL) 368122702Sandre return 1; 369122702Sandre 370122702Sandre M_ASSERTVALID(m); 371122702Sandre M_ASSERTPKTHDR(m); 372122702Sandre 373122702Sandre ip = mtod(m, struct ip *); /* m may have changed by pfil hook */ 374133497Sandre dest.s_addr = ip->ip_dst.s_addr; 375122702Sandre 376122702Sandre /* 377122702Sandre * Destination address changed? 378122702Sandre */ 379133497Sandre if (odest.s_addr != dest.s_addr) { 380122702Sandre /* 381122702Sandre * Is it now for a local address on this host? 382122702Sandre */ 383133497Sandre if (in_localip(dest)) 384133497Sandre goto forwardlocal; 385122702Sandre /* 386122702Sandre * Go on with new destination address 387122702Sandre */ 388122702Sandre } 389133920Sandre#ifdef IPFIREWALL_FORWARD 390133920Sandre if (m->m_flags & M_FASTFWD_OURS) { 391133920Sandre /* 392133920Sandre * ipfw changed it for a local address on this host. 393133920Sandre */ 394133920Sandre goto forwardlocal; 395133920Sandre } 396133920Sandre#endif /* IPFIREWALL_FORWARD */ 397122702Sandre 398134383Sandrepassin: 399122702Sandre /* 400122702Sandre * Step 4: decrement TTL and look up route 401122702Sandre */ 402122702Sandre 403122702Sandre /* 404122702Sandre * Check TTL 405122702Sandre */ 406122702Sandre#ifdef IPSTEALTH 407122702Sandre if (!ipstealth) { 408122702Sandre#endif 409122702Sandre if (ip->ip_ttl <= IPTTLDEC) { 410123740Speter icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 0, NULL); 411122702Sandre return 1; 412122702Sandre } 413122702Sandre 414122702Sandre /* 415136690Sandre * Decrement the TTL and incrementally change the IP header checksum. 416136690Sandre * Don't bother doing this with hw checksum offloading, it's faster 417136690Sandre * doing it right here. 418122702Sandre */ 419122702Sandre ip->ip_ttl -= IPTTLDEC; 420122702Sandre if (ip->ip_sum >= (u_int16_t) ~htons(IPTTLDEC << 8)) 421122702Sandre ip->ip_sum -= ~htons(IPTTLDEC << 8); 422122702Sandre else 423122702Sandre ip->ip_sum += htons(IPTTLDEC << 8); 424122702Sandre#ifdef IPSTEALTH 425122702Sandre } 426122702Sandre#endif 427122702Sandre 428122702Sandre /* 429122702Sandre * Find route to destination. 430122702Sandre */ 431128872Sandre if ((dst = ip_findroute(&ro, dest, m)) == NULL) 432128872Sandre return 1; /* icmp unreach already sent */ 433128872Sandre ifp = ro.ro_rt->rt_ifp; 434122702Sandre 435122702Sandre /* 436137179Sbms * Immediately drop blackholed traffic. 437137179Sbms */ 438137179Sbms if (ro.ro_rt->rt_flags & RTF_BLACKHOLE) 439137179Sbms goto drop; 440137179Sbms 441137179Sbms /* 442122702Sandre * Step 5: outgoing firewall packet processing 443122702Sandre */ 444122702Sandre 445122702Sandre /* 446122702Sandre * Run through list of hooks for output packets. 447122702Sandre */ 448134383Sandre if (inet_pfil_hook.ph_busy_count == -1) 449134383Sandre goto passout; 450134383Sandre 451135920Smlaier if (pfil_run_hooks(&inet_pfil_hook, &m, ifp, PFIL_OUT, NULL) || m == NULL) { 452128872Sandre goto consumed; 453122702Sandre } 454122702Sandre 455122702Sandre M_ASSERTVALID(m); 456122702Sandre M_ASSERTPKTHDR(m); 457122702Sandre 458122702Sandre ip = mtod(m, struct ip *); 459133497Sandre dest.s_addr = ip->ip_dst.s_addr; 460122702Sandre 461122702Sandre /* 462122702Sandre * Destination address changed? 463122702Sandre */ 464133920Sandre#ifndef IPFIREWALL_FORWARD 465133497Sandre if (odest.s_addr != dest.s_addr) { 466133920Sandre#else 467133920Sandre fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 468133920Sandre if (odest.s_addr != dest.s_addr || fwd_tag != NULL) { 469133920Sandre#endif /* IPFIREWALL_FORWARD */ 470122702Sandre /* 471122702Sandre * Is it now for a local address on this host? 472122702Sandre */ 473133920Sandre#ifndef IPFIREWALL_FORWARD 474133497Sandre if (in_localip(dest)) { 475133920Sandre#else 476136690Sandre if (m->m_flags & M_FASTFWD_OURS || in_localip(dest)) { 477133920Sandre#endif /* IPFIREWALL_FORWARD */ 478122702Sandreforwardlocal: 479133497Sandre /* 480135158Sandre * Return packet for processing by ip_input(). 481135158Sandre * Keep host byte order as expected at ip_input's 482135158Sandre * "ours"-label. 483133497Sandre */ 484135158Sandre m->m_flags |= M_FASTFWD_OURS; 485133497Sandre if (ro.ro_rt) 486133497Sandre RTFREE(ro.ro_rt); 487133497Sandre return 0; 488122702Sandre } 489122702Sandre /* 490122702Sandre * Redo route lookup with new destination address 491122702Sandre */ 492133920Sandre#ifdef IPFIREWALL_FORWARD 493133920Sandre if (fwd_tag) { 494133920Sandre if (!in_localip(ip->ip_src) && !in_localaddr(ip->ip_dst)) 495133920Sandre dest.s_addr = ((struct sockaddr_in *)(fwd_tag+1))->sin_addr.s_addr; 496133920Sandre m_tag_delete(m, fwd_tag); 497133920Sandre } 498133920Sandre#endif /* IPFIREWALL_FORWARD */ 499122702Sandre RTFREE(ro.ro_rt); 500128872Sandre if ((dst = ip_findroute(&ro, dest, m)) == NULL) 501128872Sandre return 1; /* icmp unreach already sent */ 502128872Sandre ifp = ro.ro_rt->rt_ifp; 503122702Sandre } 504122702Sandre 505134383Sandrepassout: 506122702Sandre /* 507122702Sandre * Step 6: send off the packet 508122702Sandre */ 509122702Sandre 510122702Sandre /* 511128872Sandre * Check if route is dampned (when ARP is unable to resolve) 512128872Sandre */ 513128872Sandre if ((ro.ro_rt->rt_flags & RTF_REJECT) && 514128872Sandre ro.ro_rt->rt_rmx.rmx_expire >= time_second) { 515128872Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, NULL); 516128872Sandre goto consumed; 517128872Sandre } 518128872Sandre 519133480Sandre#ifndef ALTQ 520128872Sandre /* 521128872Sandre * Check if there is enough space in the interface queue 522128872Sandre */ 523128872Sandre if ((ifp->if_snd.ifq_len + ip->ip_len / ifp->if_mtu + 1) >= 524128872Sandre ifp->if_snd.ifq_maxlen) { 525128872Sandre ipstat.ips_odropped++; 526128872Sandre /* would send source quench here but that is depreciated */ 527128872Sandre goto drop; 528128872Sandre } 529133480Sandre#endif 530128872Sandre 531128872Sandre /* 532128872Sandre * Check if media link state of interface is not down 533128872Sandre */ 534128872Sandre if (ifp->if_link_state == LINK_STATE_DOWN) { 535128872Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, NULL); 536128872Sandre goto consumed; 537128872Sandre } 538128872Sandre 539128872Sandre /* 540122702Sandre * Check if packet fits MTU or if hardware will fragement for us 541122702Sandre */ 542122702Sandre if (ro.ro_rt->rt_rmx.rmx_mtu) 543122702Sandre mtu = min(ro.ro_rt->rt_rmx.rmx_mtu, ifp->if_mtu); 544122702Sandre else 545122702Sandre mtu = ifp->if_mtu; 546122702Sandre 547122702Sandre if (ip->ip_len <= mtu || 548122702Sandre (ifp->if_hwassist & CSUM_FRAGMENT && (ip->ip_off & IP_DF) == 0)) { 549122702Sandre /* 550122702Sandre * Restore packet header fields to original values 551122702Sandre */ 552122702Sandre ip->ip_len = htons(ip->ip_len); 553122702Sandre ip->ip_off = htons(ip->ip_off); 554122702Sandre /* 555122702Sandre * Send off the packet via outgoing interface 556122702Sandre */ 557122702Sandre error = (*ifp->if_output)(ifp, m, 558122702Sandre (struct sockaddr *)dst, ro.ro_rt); 559122702Sandre } else { 560122702Sandre /* 561128872Sandre * Handle EMSGSIZE with icmp reply needfrag for TCP MTU discovery 562122702Sandre */ 563122702Sandre if (ip->ip_off & IP_DF) { 564128872Sandre ipstat.ips_cantfrag++; 565122702Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NEEDFRAG, 566123740Speter 0, ifp); 567128872Sandre goto consumed; 568122702Sandre } else { 569122702Sandre /* 570122702Sandre * We have to fragement the packet 571122702Sandre */ 572122702Sandre m->m_pkthdr.csum_flags |= CSUM_IP; 573128872Sandre /* 574128872Sandre * ip_fragment expects ip_len and ip_off in host byte 575128872Sandre * order but returns all packets in network byte order 576128872Sandre */ 577122702Sandre if (ip_fragment(ip, &m, mtu, ifp->if_hwassist, 578122702Sandre (~ifp->if_hwassist & CSUM_DELAY_IP))) { 579122702Sandre goto drop; 580122702Sandre } 581122702Sandre KASSERT(m != NULL, ("null mbuf and no error")); 582122702Sandre /* 583122702Sandre * Send off the fragments via outgoing interface 584122702Sandre */ 585122702Sandre error = 0; 586122702Sandre do { 587122702Sandre m0 = m->m_nextpkt; 588122702Sandre m->m_nextpkt = NULL; 589122702Sandre 590122702Sandre error = (*ifp->if_output)(ifp, m, 591122702Sandre (struct sockaddr *)dst, ro.ro_rt); 592122702Sandre if (error) 593122702Sandre break; 594122702Sandre } while ((m = m0) != NULL); 595122702Sandre if (error) { 596122702Sandre /* Reclaim remaining fragments */ 597144301Sglebius for (m = m0; m; m = m0) { 598122702Sandre m0 = m->m_nextpkt; 599122702Sandre m_freem(m); 600122702Sandre } 601122702Sandre } else 602122702Sandre ipstat.ips_fragmented++; 603122702Sandre } 604122702Sandre } 605122702Sandre 606122702Sandre if (error != 0) 607122702Sandre ipstat.ips_odropped++; 608122702Sandre else { 609122702Sandre ro.ro_rt->rt_rmx.rmx_pksent++; 610122702Sandre ipstat.ips_forward++; 611122702Sandre ipstat.ips_fastforward++; 612122702Sandre } 613128872Sandreconsumed: 614122702Sandre RTFREE(ro.ro_rt); 615122702Sandre return 1; 616122702Sandredrop: 617122702Sandre if (m) 618122702Sandre m_freem(m); 619128872Sandre if (ro.ro_rt) 620128872Sandre RTFREE(ro.ro_rt); 621122702Sandre return 1; 622122702Sandre} 623