ip_fastfwd.c revision 161380
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 161380 2006-08-17 00:37:03Z julian $ 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 37148324Skeramida * 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 * 44148324Skeramida * We handle basic errors, IP header errors, checksum errors, 45122702Sandre * destination unreachable, fragmentation and fragmentation needed and 46148324Skeramida * 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 * 61148324Skeramida * 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 66148324Skeramida * ICMP redirects to connected hosts if the destination router was not the 67148324Skeramida * default gateway. In one case it was filling the routing table of a host 68148324Skeramida * with approximately 300.000 cloned redirect entries until it ran out of 69148324Skeramida * kernel memory. However the networking code proved very robust and it didn't 70148324Skeramida * crash or fail in other ways. 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> 103152592Sandre#include <netinet/ip_options.h> 104122702Sandre 105122702Sandre#include <machine/in_cksum.h> 106122702Sandre 107122702Sandrestatic int ipfastforward_active = 0; 108122702SandreSYSCTL_INT(_net_inet_ip, OID_AUTO, fastforwarding, CTLFLAG_RW, 109122702Sandre &ipfastforward_active, 0, "Enable fast IP forwarding"); 110122702Sandre 111128872Sandrestatic struct sockaddr_in * 112133497Sandreip_findroute(struct route *ro, struct in_addr dest, struct mbuf *m) 113128872Sandre{ 114128872Sandre struct sockaddr_in *dst; 115128872Sandre struct rtentry *rt; 116128872Sandre 117128872Sandre /* 118128872Sandre * Find route to destination. 119128872Sandre */ 120128872Sandre bzero(ro, sizeof(*ro)); 121128872Sandre dst = (struct sockaddr_in *)&ro->ro_dst; 122128872Sandre dst->sin_family = AF_INET; 123128872Sandre dst->sin_len = sizeof(*dst); 124133497Sandre dst->sin_addr.s_addr = dest.s_addr; 125128872Sandre rtalloc_ign(ro, RTF_CLONING); 126128872Sandre 127128872Sandre /* 128128872Sandre * Route there and interface still up? 129128872Sandre */ 130128872Sandre rt = ro->ro_rt; 131128872Sandre if (rt && (rt->rt_flags & RTF_UP) && 132128872Sandre (rt->rt_ifp->if_flags & IFF_UP) && 133148887Srwatson (rt->rt_ifp->if_drv_flags & IFF_DRV_RUNNING)) { 134128872Sandre if (rt->rt_flags & RTF_GATEWAY) 135128872Sandre dst = (struct sockaddr_in *)rt->rt_gateway; 136128872Sandre } else { 137128872Sandre ipstat.ips_noroute++; 138128872Sandre ipstat.ips_cantforward++; 139128872Sandre if (rt) 140128872Sandre RTFREE(rt); 141145863Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 142128872Sandre return NULL; 143128872Sandre } 144128872Sandre return dst; 145128872Sandre} 146128872Sandre 147122702Sandre/* 148122702Sandre * Try to forward a packet based on the destination address. 149122702Sandre * This is a fast path optimized for the plain forwarding case. 150122702Sandre * If the packet is handled (and consumed) here then we return 1; 151122702Sandre * otherwise 0 is returned and the packet should be delivered 152122702Sandre * to ip_input for full processing. 153122702Sandre */ 154154518Sandrestruct mbuf * 155122702Sandreip_fastforward(struct mbuf *m) 156122702Sandre{ 157122702Sandre struct ip *ip; 158122702Sandre struct mbuf *m0 = NULL; 159122702Sandre struct route ro; 160122702Sandre struct sockaddr_in *dst = NULL; 161128872Sandre struct ifnet *ifp; 162133497Sandre struct in_addr odest, dest; 163128872Sandre u_short sum, ip_len; 164122702Sandre int error = 0; 165133920Sandre int hlen, mtu; 166133920Sandre#ifdef IPFIREWALL_FORWARD 167133920Sandre struct m_tag *fwd_tag; 168133920Sandre#endif 169122702Sandre 170122702Sandre /* 171122702Sandre * Are we active and forwarding packets? 172122702Sandre */ 173122702Sandre if (!ipfastforward_active || !ipforwarding) 174154518Sandre return m; 175122702Sandre 176122702Sandre M_ASSERTVALID(m); 177122702Sandre M_ASSERTPKTHDR(m); 178122702Sandre 179128872Sandre ro.ro_rt = NULL; 180128872Sandre 181122702Sandre /* 182122702Sandre * Step 1: check for packet drop conditions (and sanity checks) 183122702Sandre */ 184122702Sandre 185122702Sandre /* 186122702Sandre * Is entire packet big enough? 187122702Sandre */ 188122702Sandre if (m->m_pkthdr.len < sizeof(struct ip)) { 189122702Sandre ipstat.ips_tooshort++; 190122702Sandre goto drop; 191122702Sandre } 192122702Sandre 193122702Sandre /* 194122702Sandre * Is first mbuf large enough for ip header and is header present? 195122702Sandre */ 196122702Sandre if (m->m_len < sizeof (struct ip) && 197137302Sandre (m = m_pullup(m, sizeof (struct ip))) == NULL) { 198122702Sandre ipstat.ips_toosmall++; 199154518Sandre return NULL; /* mbuf already free'd */ 200122702Sandre } 201122702Sandre 202122702Sandre ip = mtod(m, struct ip *); 203122702Sandre 204122702Sandre /* 205122702Sandre * Is it IPv4? 206122702Sandre */ 207122702Sandre if (ip->ip_v != IPVERSION) { 208122702Sandre ipstat.ips_badvers++; 209122702Sandre goto drop; 210122702Sandre } 211122702Sandre 212122702Sandre /* 213122702Sandre * Is IP header length correct and is it in first mbuf? 214122702Sandre */ 215122702Sandre hlen = ip->ip_hl << 2; 216122702Sandre if (hlen < sizeof(struct ip)) { /* minimum header length */ 217122702Sandre ipstat.ips_badlen++; 218122702Sandre goto drop; 219122702Sandre } 220122702Sandre if (hlen > m->m_len) { 221154518Sandre if ((m = m_pullup(m, hlen)) == NULL) { 222122702Sandre ipstat.ips_badhlen++; 223154518Sandre return NULL; /* mbuf already free'd */ 224122702Sandre } 225122702Sandre ip = mtod(m, struct ip *); 226122702Sandre } 227122702Sandre 228122702Sandre /* 229122702Sandre * Checksum correct? 230122702Sandre */ 231122702Sandre if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) 232122702Sandre sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID); 233122702Sandre else { 234122702Sandre if (hlen == sizeof(struct ip)) 235122702Sandre sum = in_cksum_hdr(ip); 236122702Sandre else 237122702Sandre sum = in_cksum(m, hlen); 238122702Sandre } 239122702Sandre if (sum) { 240122702Sandre ipstat.ips_badsum++; 241122702Sandre goto drop; 242122702Sandre } 243136690Sandre 244136690Sandre /* 245148324Skeramida * Remember that we have checked the IP header and found it valid. 246136690Sandre */ 247122702Sandre m->m_pkthdr.csum_flags |= (CSUM_IP_CHECKED | CSUM_IP_VALID); 248122702Sandre 249128872Sandre ip_len = ntohs(ip->ip_len); 250122702Sandre 251122702Sandre /* 252122702Sandre * Is IP length longer than packet we have got? 253122702Sandre */ 254128872Sandre if (m->m_pkthdr.len < ip_len) { 255122702Sandre ipstat.ips_tooshort++; 256122702Sandre goto drop; 257122702Sandre } 258122702Sandre 259122702Sandre /* 260122702Sandre * Is packet longer than IP header tells us? If yes, truncate packet. 261122702Sandre */ 262128872Sandre if (m->m_pkthdr.len > ip_len) { 263122702Sandre if (m->m_len == m->m_pkthdr.len) { 264128872Sandre m->m_len = ip_len; 265128872Sandre m->m_pkthdr.len = ip_len; 266122702Sandre } else 267128872Sandre m_adj(m, ip_len - m->m_pkthdr.len); 268122702Sandre } 269122702Sandre 270122702Sandre /* 271122702Sandre * Is packet from or to 127/8? 272122702Sandre */ 273122702Sandre if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 274122702Sandre (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 275122702Sandre ipstat.ips_badaddr++; 276122702Sandre goto drop; 277122702Sandre } 278122702Sandre 279133480Sandre#ifdef ALTQ 280122702Sandre /* 281133480Sandre * Is packet dropped by traffic conditioner? 282133480Sandre */ 283133480Sandre if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) 284154518Sandre goto drop; 285133480Sandre#endif 286133480Sandre 287133480Sandre /* 288122702Sandre * Step 2: fallback conditions to normal ip_input path processing 289122702Sandre */ 290122702Sandre 291122702Sandre /* 292122702Sandre * Only IP packets without options 293122702Sandre */ 294129017Sandre if (ip->ip_hl != (sizeof(struct ip) >> 2)) { 295129017Sandre if (ip_doopts == 1) 296154518Sandre return m; 297129017Sandre else if (ip_doopts == 2) { 298129017Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_FILTER_PROHIB, 299145863Sandre 0, 0); 300154518Sandre return NULL; /* mbuf already free'd */ 301129017Sandre } 302129017Sandre /* else ignore IP options and continue */ 303129017Sandre } 304122702Sandre 305122702Sandre /* 306122702Sandre * Only unicast IP, not from loopback, no L2 or IP broadcast, 307122702Sandre * no multicast, no INADDR_ANY 308122702Sandre * 309122702Sandre * XXX: Probably some of these checks could be direct drop 310122702Sandre * conditions. However it is not clear whether there are some 311122702Sandre * hacks or obscure behaviours which make it neccessary to 312122702Sandre * let ip_input handle it. We play safe here and let ip_input 313122702Sandre * deal with it until it is proven that we can directly drop it. 314122702Sandre */ 315149369Sandre if ((m->m_flags & (M_BCAST|M_MCAST)) || 316149369Sandre (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)) || 321149369Sandre ip->ip_src.s_addr == INADDR_ANY || 322122702Sandre ip->ip_dst.s_addr == INADDR_ANY ) 323154518Sandre return m; 324122702Sandre 325122702Sandre /* 326122702Sandre * Is it for a local address on this host? 327122702Sandre */ 328133497Sandre if (in_localip(ip->ip_dst)) 329154518Sandre return m; 330122702Sandre 331122702Sandre ipstat.ips_total++; 332122702Sandre 333122702Sandre /* 334122702Sandre * Step 3: incoming packet firewall processing 335122702Sandre */ 336122702Sandre 337128872Sandre /* 338128872Sandre * Convert to host representation 339128872Sandre */ 340128872Sandre ip->ip_len = ntohs(ip->ip_len); 341128872Sandre ip->ip_off = ntohs(ip->ip_off); 342128872Sandre 343133497Sandre odest.s_addr = dest.s_addr = ip->ip_dst.s_addr; 344134383Sandre 345122702Sandre /* 346122702Sandre * Run through list of ipfilter hooks for input packets 347122702Sandre */ 348155201Scsjp if (!PFIL_HOOKED(&inet_pfil_hook)) 349134383Sandre goto passin; 350134383Sandre 351135920Smlaier if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, PFIL_IN, NULL) || 352122702Sandre m == NULL) 353154518Sandre goto drop; 354122702Sandre 355122702Sandre M_ASSERTVALID(m); 356122702Sandre M_ASSERTPKTHDR(m); 357122702Sandre 358122702Sandre ip = mtod(m, struct ip *); /* m may have changed by pfil hook */ 359133497Sandre dest.s_addr = ip->ip_dst.s_addr; 360122702Sandre 361122702Sandre /* 362122702Sandre * Destination address changed? 363122702Sandre */ 364133497Sandre if (odest.s_addr != dest.s_addr) { 365122702Sandre /* 366122702Sandre * Is it now for a local address on this host? 367122702Sandre */ 368133497Sandre if (in_localip(dest)) 369133497Sandre goto forwardlocal; 370122702Sandre /* 371122702Sandre * Go on with new destination address 372122702Sandre */ 373122702Sandre } 374133920Sandre#ifdef IPFIREWALL_FORWARD 375133920Sandre if (m->m_flags & M_FASTFWD_OURS) { 376133920Sandre /* 377133920Sandre * ipfw changed it for a local address on this host. 378133920Sandre */ 379133920Sandre goto forwardlocal; 380133920Sandre } 381133920Sandre#endif /* IPFIREWALL_FORWARD */ 382122702Sandre 383134383Sandrepassin: 384122702Sandre /* 385122702Sandre * Step 4: decrement TTL and look up route 386122702Sandre */ 387122702Sandre 388122702Sandre /* 389122702Sandre * Check TTL 390122702Sandre */ 391122702Sandre#ifdef IPSTEALTH 392122702Sandre if (!ipstealth) { 393122702Sandre#endif 394122702Sandre if (ip->ip_ttl <= IPTTLDEC) { 395145863Sandre icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 0, 0); 396154518Sandre return NULL; /* mbuf already free'd */ 397122702Sandre } 398122702Sandre 399122702Sandre /* 400136690Sandre * Decrement the TTL and incrementally change the IP header checksum. 401136690Sandre * Don't bother doing this with hw checksum offloading, it's faster 402136690Sandre * doing it right here. 403122702Sandre */ 404122702Sandre ip->ip_ttl -= IPTTLDEC; 405122702Sandre if (ip->ip_sum >= (u_int16_t) ~htons(IPTTLDEC << 8)) 406122702Sandre ip->ip_sum -= ~htons(IPTTLDEC << 8); 407122702Sandre else 408122702Sandre ip->ip_sum += htons(IPTTLDEC << 8); 409122702Sandre#ifdef IPSTEALTH 410122702Sandre } 411122702Sandre#endif 412122702Sandre 413122702Sandre /* 414122702Sandre * Find route to destination. 415122702Sandre */ 416128872Sandre if ((dst = ip_findroute(&ro, dest, m)) == NULL) 417154518Sandre return NULL; /* icmp unreach already sent */ 418128872Sandre ifp = ro.ro_rt->rt_ifp; 419122702Sandre 420122702Sandre /* 421137179Sbms * Immediately drop blackholed traffic. 422137179Sbms */ 423137179Sbms if (ro.ro_rt->rt_flags & RTF_BLACKHOLE) 424137179Sbms goto drop; 425137179Sbms 426137179Sbms /* 427122702Sandre * Step 5: outgoing firewall packet processing 428122702Sandre */ 429122702Sandre 430122702Sandre /* 431122702Sandre * Run through list of hooks for output packets. 432122702Sandre */ 433155201Scsjp if (!PFIL_HOOKED(&inet_pfil_hook)) 434134383Sandre goto passout; 435134383Sandre 436135920Smlaier if (pfil_run_hooks(&inet_pfil_hook, &m, ifp, PFIL_OUT, NULL) || m == NULL) { 437154518Sandre goto drop; 438122702Sandre } 439122702Sandre 440122702Sandre M_ASSERTVALID(m); 441122702Sandre M_ASSERTPKTHDR(m); 442122702Sandre 443122702Sandre ip = mtod(m, struct ip *); 444133497Sandre dest.s_addr = ip->ip_dst.s_addr; 445122702Sandre 446122702Sandre /* 447122702Sandre * Destination address changed? 448122702Sandre */ 449133920Sandre#ifndef IPFIREWALL_FORWARD 450133497Sandre if (odest.s_addr != dest.s_addr) { 451133920Sandre#else 452133920Sandre fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 453133920Sandre if (odest.s_addr != dest.s_addr || fwd_tag != NULL) { 454133920Sandre#endif /* IPFIREWALL_FORWARD */ 455122702Sandre /* 456122702Sandre * Is it now for a local address on this host? 457122702Sandre */ 458133920Sandre#ifndef IPFIREWALL_FORWARD 459133497Sandre if (in_localip(dest)) { 460133920Sandre#else 461136690Sandre if (m->m_flags & M_FASTFWD_OURS || in_localip(dest)) { 462133920Sandre#endif /* IPFIREWALL_FORWARD */ 463122702Sandreforwardlocal: 464133497Sandre /* 465135158Sandre * Return packet for processing by ip_input(). 466135158Sandre * Keep host byte order as expected at ip_input's 467135158Sandre * "ours"-label. 468133497Sandre */ 469135158Sandre m->m_flags |= M_FASTFWD_OURS; 470133497Sandre if (ro.ro_rt) 471133497Sandre RTFREE(ro.ro_rt); 472154518Sandre return m; 473122702Sandre } 474122702Sandre /* 475122702Sandre * Redo route lookup with new destination address 476122702Sandre */ 477133920Sandre#ifdef IPFIREWALL_FORWARD 478133920Sandre if (fwd_tag) { 479161380Sjulian dest.s_addr = ((struct sockaddr_in *) 480157833Sglebius (fwd_tag + 1))->sin_addr.s_addr; 481133920Sandre m_tag_delete(m, fwd_tag); 482133920Sandre } 483133920Sandre#endif /* IPFIREWALL_FORWARD */ 484122702Sandre RTFREE(ro.ro_rt); 485128872Sandre if ((dst = ip_findroute(&ro, dest, m)) == NULL) 486154518Sandre return NULL; /* icmp unreach already sent */ 487128872Sandre ifp = ro.ro_rt->rt_ifp; 488122702Sandre } 489122702Sandre 490134383Sandrepassout: 491122702Sandre /* 492122702Sandre * Step 6: send off the packet 493122702Sandre */ 494122702Sandre 495122702Sandre /* 496128872Sandre * Check if route is dampned (when ARP is unable to resolve) 497128872Sandre */ 498128872Sandre if ((ro.ro_rt->rt_flags & RTF_REJECT) && 499150351Sandre ro.ro_rt->rt_rmx.rmx_expire >= time_uptime) { 500145863Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 501128872Sandre goto consumed; 502128872Sandre } 503128872Sandre 504133480Sandre#ifndef ALTQ 505128872Sandre /* 506128872Sandre * Check if there is enough space in the interface queue 507128872Sandre */ 508128872Sandre if ((ifp->if_snd.ifq_len + ip->ip_len / ifp->if_mtu + 1) >= 509128872Sandre ifp->if_snd.ifq_maxlen) { 510128872Sandre ipstat.ips_odropped++; 511128872Sandre /* would send source quench here but that is depreciated */ 512128872Sandre goto drop; 513128872Sandre } 514133480Sandre#endif 515128872Sandre 516128872Sandre /* 517128872Sandre * Check if media link state of interface is not down 518128872Sandre */ 519128872Sandre if (ifp->if_link_state == LINK_STATE_DOWN) { 520145863Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0); 521128872Sandre goto consumed; 522128872Sandre } 523128872Sandre 524128872Sandre /* 525148324Skeramida * Check if packet fits MTU or if hardware will fragment for us 526122702Sandre */ 527122702Sandre if (ro.ro_rt->rt_rmx.rmx_mtu) 528122702Sandre mtu = min(ro.ro_rt->rt_rmx.rmx_mtu, ifp->if_mtu); 529122702Sandre else 530122702Sandre mtu = ifp->if_mtu; 531122702Sandre 532122702Sandre if (ip->ip_len <= mtu || 533122702Sandre (ifp->if_hwassist & CSUM_FRAGMENT && (ip->ip_off & IP_DF) == 0)) { 534122702Sandre /* 535122702Sandre * Restore packet header fields to original values 536122702Sandre */ 537122702Sandre ip->ip_len = htons(ip->ip_len); 538122702Sandre ip->ip_off = htons(ip->ip_off); 539122702Sandre /* 540122702Sandre * Send off the packet via outgoing interface 541122702Sandre */ 542122702Sandre error = (*ifp->if_output)(ifp, m, 543122702Sandre (struct sockaddr *)dst, ro.ro_rt); 544122702Sandre } else { 545122702Sandre /* 546128872Sandre * Handle EMSGSIZE with icmp reply needfrag for TCP MTU discovery 547122702Sandre */ 548122702Sandre if (ip->ip_off & IP_DF) { 549128872Sandre ipstat.ips_cantfrag++; 550122702Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NEEDFRAG, 551145863Sandre 0, mtu); 552128872Sandre goto consumed; 553122702Sandre } else { 554122702Sandre /* 555148324Skeramida * We have to fragment the packet 556122702Sandre */ 557122702Sandre m->m_pkthdr.csum_flags |= CSUM_IP; 558128872Sandre /* 559128872Sandre * ip_fragment expects ip_len and ip_off in host byte 560128872Sandre * order but returns all packets in network byte order 561128872Sandre */ 562122702Sandre if (ip_fragment(ip, &m, mtu, ifp->if_hwassist, 563122702Sandre (~ifp->if_hwassist & CSUM_DELAY_IP))) { 564122702Sandre goto drop; 565122702Sandre } 566122702Sandre KASSERT(m != NULL, ("null mbuf and no error")); 567122702Sandre /* 568122702Sandre * Send off the fragments via outgoing interface 569122702Sandre */ 570122702Sandre error = 0; 571122702Sandre do { 572122702Sandre m0 = m->m_nextpkt; 573122702Sandre m->m_nextpkt = NULL; 574122702Sandre 575122702Sandre error = (*ifp->if_output)(ifp, m, 576122702Sandre (struct sockaddr *)dst, ro.ro_rt); 577122702Sandre if (error) 578122702Sandre break; 579122702Sandre } while ((m = m0) != NULL); 580122702Sandre if (error) { 581122702Sandre /* Reclaim remaining fragments */ 582144301Sglebius for (m = m0; m; m = m0) { 583122702Sandre m0 = m->m_nextpkt; 584122702Sandre m_freem(m); 585122702Sandre } 586122702Sandre } else 587122702Sandre ipstat.ips_fragmented++; 588122702Sandre } 589122702Sandre } 590122702Sandre 591122702Sandre if (error != 0) 592122702Sandre ipstat.ips_odropped++; 593122702Sandre else { 594122702Sandre ro.ro_rt->rt_rmx.rmx_pksent++; 595122702Sandre ipstat.ips_forward++; 596122702Sandre ipstat.ips_fastforward++; 597122702Sandre } 598128872Sandreconsumed: 599122702Sandre RTFREE(ro.ro_rt); 600154518Sandre return NULL; 601122702Sandredrop: 602122702Sandre if (m) 603122702Sandre m_freem(m); 604128872Sandre if (ro.ro_rt) 605128872Sandre RTFREE(ro.ro_rt); 606154518Sandre return NULL; 607122702Sandre} 608