ip_fastfwd.c revision 135158
1122702Sandre/* 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 135158 2004-09-13 17:01:53Z andre $ 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) && 198122702Sandre (m = m_pullup(m, sizeof (struct ip))) == 0) { 199122702Sandre ipstat.ips_toosmall++; 200122702Sandre goto drop; 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++; 224122702Sandre goto drop; 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 } 244122702Sandre m->m_pkthdr.csum_flags |= (CSUM_IP_CHECKED | CSUM_IP_VALID); 245122702Sandre 246128872Sandre ip_len = ntohs(ip->ip_len); 247122702Sandre 248122702Sandre /* 249122702Sandre * Is IP length longer than packet we have got? 250122702Sandre */ 251128872Sandre if (m->m_pkthdr.len < ip_len) { 252122702Sandre ipstat.ips_tooshort++; 253122702Sandre goto drop; 254122702Sandre } 255122702Sandre 256122702Sandre /* 257122702Sandre * Is packet longer than IP header tells us? If yes, truncate packet. 258122702Sandre */ 259128872Sandre if (m->m_pkthdr.len > ip_len) { 260122702Sandre if (m->m_len == m->m_pkthdr.len) { 261128872Sandre m->m_len = ip_len; 262128872Sandre m->m_pkthdr.len = ip_len; 263122702Sandre } else 264128872Sandre m_adj(m, ip_len - m->m_pkthdr.len); 265122702Sandre } 266122702Sandre 267122702Sandre /* 268122702Sandre * Is packet from or to 127/8? 269122702Sandre */ 270122702Sandre if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 271122702Sandre (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 272122702Sandre ipstat.ips_badaddr++; 273122702Sandre goto drop; 274122702Sandre } 275122702Sandre 276133480Sandre#ifdef ALTQ 277122702Sandre /* 278133480Sandre * Is packet dropped by traffic conditioner? 279133480Sandre */ 280133480Sandre if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) 281133480Sandre return 1; 282133480Sandre#endif 283133480Sandre 284133480Sandre /* 285122702Sandre * Step 2: fallback conditions to normal ip_input path processing 286122702Sandre */ 287122702Sandre 288122702Sandre /* 289122702Sandre * Only IP packets without options 290122702Sandre */ 291129017Sandre if (ip->ip_hl != (sizeof(struct ip) >> 2)) { 292129017Sandre if (ip_doopts == 1) 293129017Sandre return 0; 294129017Sandre else if (ip_doopts == 2) { 295129017Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_FILTER_PROHIB, 296129017Sandre 0, NULL); 297129017Sandre return 1; 298129017Sandre } 299129017Sandre /* else ignore IP options and continue */ 300129017Sandre } 301122702Sandre 302122702Sandre /* 303122702Sandre * Only unicast IP, not from loopback, no L2 or IP broadcast, 304122702Sandre * no multicast, no INADDR_ANY 305122702Sandre * 306122702Sandre * XXX: Probably some of these checks could be direct drop 307122702Sandre * conditions. However it is not clear whether there are some 308122702Sandre * hacks or obscure behaviours which make it neccessary to 309122702Sandre * let ip_input handle it. We play safe here and let ip_input 310122702Sandre * deal with it until it is proven that we can directly drop it. 311122702Sandre */ 312122702Sandre if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) || 313122702Sandre ntohl(ip->ip_src.s_addr) == (u_long)INADDR_BROADCAST || 314122702Sandre ntohl(ip->ip_dst.s_addr) == (u_long)INADDR_BROADCAST || 315122702Sandre IN_MULTICAST(ntohl(ip->ip_src.s_addr)) || 316122702Sandre IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) || 317122702Sandre ip->ip_dst.s_addr == INADDR_ANY ) 318128872Sandre return 0; 319122702Sandre 320122702Sandre /* 321122702Sandre * Is it for a local address on this host? 322122702Sandre */ 323133497Sandre if (in_localip(ip->ip_dst)) 324133497Sandre return 0; 325122702Sandre 326122702Sandre /* 327122702Sandre * Or is it for a local IP broadcast address on this host? 328122702Sandre */ 329133482Sandre if ((m->m_flags & M_BCAST) && 330133482Sandre (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST)) { 331122702Sandre TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { 332122702Sandre if (ifa->ifa_addr->sa_family != AF_INET) 333122702Sandre continue; 334122702Sandre ia = ifatoia(ifa); 335122702Sandre if (ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr) 336128872Sandre return 0; 337122702Sandre if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == 338122702Sandre ip->ip_dst.s_addr) 339128872Sandre return 0; 340122702Sandre } 341122702Sandre } 342122702Sandre ipstat.ips_total++; 343122702Sandre 344122702Sandre /* 345122702Sandre * Step 3: incoming packet firewall processing 346122702Sandre */ 347122702Sandre 348128872Sandre /* 349128872Sandre * Convert to host representation 350128872Sandre */ 351128872Sandre ip->ip_len = ntohs(ip->ip_len); 352128872Sandre ip->ip_off = ntohs(ip->ip_off); 353128872Sandre 354133497Sandre odest.s_addr = dest.s_addr = ip->ip_dst.s_addr; 355134383Sandre 356122702Sandre /* 357122702Sandre * Run through list of ipfilter hooks for input packets 358122702Sandre */ 359134383Sandre if (inet_pfil_hook.ph_busy_count == -1) 360134383Sandre goto passin; 361134383Sandre 362122702Sandre if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, PFIL_IN) || 363122702Sandre m == NULL) 364122702Sandre return 1; 365122702Sandre 366122702Sandre M_ASSERTVALID(m); 367122702Sandre M_ASSERTPKTHDR(m); 368122702Sandre 369122702Sandre ip = mtod(m, struct ip *); /* m may have changed by pfil hook */ 370133497Sandre dest.s_addr = ip->ip_dst.s_addr; 371122702Sandre 372122702Sandre /* 373122702Sandre * Destination address changed? 374122702Sandre */ 375133497Sandre if (odest.s_addr != dest.s_addr) { 376122702Sandre /* 377122702Sandre * Is it now for a local address on this host? 378122702Sandre */ 379133497Sandre if (in_localip(dest)) 380133497Sandre goto forwardlocal; 381122702Sandre /* 382122702Sandre * Go on with new destination address 383122702Sandre */ 384122702Sandre } 385133920Sandre#ifdef IPFIREWALL_FORWARD 386133920Sandre if (m->m_flags & M_FASTFWD_OURS) { 387133920Sandre /* 388133920Sandre * ipfw changed it for a local address on this host. 389133920Sandre */ 390133920Sandre goto forwardlocal; 391133920Sandre } 392133920Sandre#endif /* IPFIREWALL_FORWARD */ 393122702Sandre 394134383Sandrepassin: 395122702Sandre /* 396122702Sandre * Step 4: decrement TTL and look up route 397122702Sandre */ 398122702Sandre 399122702Sandre /* 400122702Sandre * Check TTL 401122702Sandre */ 402122702Sandre#ifdef IPSTEALTH 403122702Sandre if (!ipstealth) { 404122702Sandre#endif 405122702Sandre if (ip->ip_ttl <= IPTTLDEC) { 406123740Speter icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 0, NULL); 407122702Sandre return 1; 408122702Sandre } 409122702Sandre 410122702Sandre /* 411122702Sandre * Decrement the TTL and incrementally change the checksum. 412122702Sandre * Don't bother doing this with hw checksum offloading. 413122702Sandre */ 414122702Sandre ip->ip_ttl -= IPTTLDEC; 415122702Sandre if (ip->ip_sum >= (u_int16_t) ~htons(IPTTLDEC << 8)) 416122702Sandre ip->ip_sum -= ~htons(IPTTLDEC << 8); 417122702Sandre else 418122702Sandre ip->ip_sum += htons(IPTTLDEC << 8); 419122702Sandre#ifdef IPSTEALTH 420122702Sandre } 421122702Sandre#endif 422122702Sandre 423122702Sandre /* 424122702Sandre * Find route to destination. 425122702Sandre */ 426128872Sandre if ((dst = ip_findroute(&ro, dest, m)) == NULL) 427128872Sandre return 1; /* icmp unreach already sent */ 428128872Sandre ifp = ro.ro_rt->rt_ifp; 429122702Sandre 430122702Sandre /* 431122702Sandre * Step 5: outgoing firewall packet processing 432122702Sandre */ 433122702Sandre 434122702Sandre /* 435122702Sandre * Run through list of hooks for output packets. 436122702Sandre */ 437134383Sandre if (inet_pfil_hook.ph_busy_count == -1) 438134383Sandre goto passout; 439134383Sandre 440122702Sandre if (pfil_run_hooks(&inet_pfil_hook, &m, ifp, PFIL_OUT) || m == NULL) { 441128872Sandre goto consumed; 442122702Sandre } 443122702Sandre 444122702Sandre M_ASSERTVALID(m); 445122702Sandre M_ASSERTPKTHDR(m); 446122702Sandre 447122702Sandre ip = mtod(m, struct ip *); 448133497Sandre dest.s_addr = ip->ip_dst.s_addr; 449122702Sandre 450122702Sandre /* 451122702Sandre * Destination address changed? 452122702Sandre */ 453133920Sandre#ifndef IPFIREWALL_FORWARD 454133497Sandre if (odest.s_addr != dest.s_addr) { 455133920Sandre#else 456133920Sandre fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL); 457133920Sandre if (odest.s_addr != dest.s_addr || fwd_tag != NULL) { 458133920Sandre#endif /* IPFIREWALL_FORWARD */ 459122702Sandre /* 460122702Sandre * Is it now for a local address on this host? 461122702Sandre */ 462133920Sandre#ifndef IPFIREWALL_FORWARD 463133497Sandre if (in_localip(dest)) { 464133920Sandre#else 465133920Sandre if (in_localip(dest) || m->m_flags & M_FASTFWD_OURS) { 466133920Sandre#endif /* IPFIREWALL_FORWARD */ 467122702Sandreforwardlocal: 468133497Sandre /* 469135158Sandre * Return packet for processing by ip_input(). 470135158Sandre * Keep host byte order as expected at ip_input's 471135158Sandre * "ours"-label. 472133497Sandre */ 473135158Sandre m->m_flags |= M_FASTFWD_OURS; 474133497Sandre if (ro.ro_rt) 475133497Sandre RTFREE(ro.ro_rt); 476133497Sandre return 0; 477122702Sandre } 478122702Sandre /* 479122702Sandre * Redo route lookup with new destination address 480122702Sandre */ 481133920Sandre#ifdef IPFIREWALL_FORWARD 482133920Sandre if (fwd_tag) { 483133920Sandre if (!in_localip(ip->ip_src) && !in_localaddr(ip->ip_dst)) 484133920Sandre dest.s_addr = ((struct sockaddr_in *)(fwd_tag+1))->sin_addr.s_addr; 485133920Sandre m_tag_delete(m, fwd_tag); 486133920Sandre } 487133920Sandre#endif /* IPFIREWALL_FORWARD */ 488122702Sandre RTFREE(ro.ro_rt); 489128872Sandre if ((dst = ip_findroute(&ro, dest, m)) == NULL) 490128872Sandre return 1; /* icmp unreach already sent */ 491128872Sandre ifp = ro.ro_rt->rt_ifp; 492122702Sandre } 493122702Sandre 494134383Sandrepassout: 495122702Sandre /* 496122702Sandre * Step 6: send off the packet 497122702Sandre */ 498122702Sandre 499122702Sandre /* 500128872Sandre * Check if route is dampned (when ARP is unable to resolve) 501128872Sandre */ 502128872Sandre if ((ro.ro_rt->rt_flags & RTF_REJECT) && 503128872Sandre ro.ro_rt->rt_rmx.rmx_expire >= time_second) { 504128872Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, NULL); 505128872Sandre goto consumed; 506128872Sandre } 507128872Sandre 508133480Sandre#ifndef ALTQ 509128872Sandre /* 510128872Sandre * Check if there is enough space in the interface queue 511128872Sandre */ 512128872Sandre if ((ifp->if_snd.ifq_len + ip->ip_len / ifp->if_mtu + 1) >= 513128872Sandre ifp->if_snd.ifq_maxlen) { 514128872Sandre ipstat.ips_odropped++; 515128872Sandre /* would send source quench here but that is depreciated */ 516128872Sandre goto drop; 517128872Sandre } 518133480Sandre#endif 519128872Sandre 520128872Sandre /* 521128872Sandre * Check if media link state of interface is not down 522128872Sandre */ 523128872Sandre if (ifp->if_link_state == LINK_STATE_DOWN) { 524128872Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, NULL); 525128872Sandre goto consumed; 526128872Sandre } 527128872Sandre 528128872Sandre /* 529122702Sandre * Check if packet fits MTU or if hardware will fragement for us 530122702Sandre */ 531122702Sandre if (ro.ro_rt->rt_rmx.rmx_mtu) 532122702Sandre mtu = min(ro.ro_rt->rt_rmx.rmx_mtu, ifp->if_mtu); 533122702Sandre else 534122702Sandre mtu = ifp->if_mtu; 535122702Sandre 536122702Sandre if (ip->ip_len <= mtu || 537122702Sandre (ifp->if_hwassist & CSUM_FRAGMENT && (ip->ip_off & IP_DF) == 0)) { 538122702Sandre /* 539122702Sandre * Restore packet header fields to original values 540122702Sandre */ 541122702Sandre ip->ip_len = htons(ip->ip_len); 542122702Sandre ip->ip_off = htons(ip->ip_off); 543122702Sandre /* 544122702Sandre * Send off the packet via outgoing interface 545122702Sandre */ 546122702Sandre error = (*ifp->if_output)(ifp, m, 547122702Sandre (struct sockaddr *)dst, ro.ro_rt); 548122702Sandre } else { 549122702Sandre /* 550128872Sandre * Handle EMSGSIZE with icmp reply needfrag for TCP MTU discovery 551122702Sandre */ 552122702Sandre if (ip->ip_off & IP_DF) { 553128872Sandre ipstat.ips_cantfrag++; 554122702Sandre icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NEEDFRAG, 555123740Speter 0, ifp); 556128872Sandre goto consumed; 557122702Sandre } else { 558122702Sandre /* 559122702Sandre * We have to fragement the packet 560122702Sandre */ 561122702Sandre m->m_pkthdr.csum_flags |= CSUM_IP; 562128872Sandre /* 563128872Sandre * ip_fragment expects ip_len and ip_off in host byte 564128872Sandre * order but returns all packets in network byte order 565128872Sandre */ 566122702Sandre if (ip_fragment(ip, &m, mtu, ifp->if_hwassist, 567122702Sandre (~ifp->if_hwassist & CSUM_DELAY_IP))) { 568122702Sandre goto drop; 569122702Sandre } 570122702Sandre KASSERT(m != NULL, ("null mbuf and no error")); 571122702Sandre /* 572122702Sandre * Send off the fragments via outgoing interface 573122702Sandre */ 574122702Sandre error = 0; 575122702Sandre do { 576122702Sandre m0 = m->m_nextpkt; 577122702Sandre m->m_nextpkt = NULL; 578122702Sandre 579122702Sandre error = (*ifp->if_output)(ifp, m, 580122702Sandre (struct sockaddr *)dst, ro.ro_rt); 581122702Sandre if (error) 582122702Sandre break; 583122702Sandre } while ((m = m0) != NULL); 584122702Sandre if (error) { 585122702Sandre /* Reclaim remaining fragments */ 586122702Sandre for (; m; m = m0) { 587122702Sandre m0 = m->m_nextpkt; 588122702Sandre m->m_nextpkt = NULL; 589122702Sandre m_freem(m); 590122702Sandre } 591122702Sandre } else 592122702Sandre ipstat.ips_fragmented++; 593122702Sandre } 594122702Sandre } 595122702Sandre 596122702Sandre if (error != 0) 597122702Sandre ipstat.ips_odropped++; 598122702Sandre else { 599122702Sandre ro.ro_rt->rt_rmx.rmx_pksent++; 600122702Sandre ipstat.ips_forward++; 601122702Sandre ipstat.ips_fastforward++; 602122702Sandre } 603128872Sandreconsumed: 604122702Sandre RTFREE(ro.ro_rt); 605122702Sandre return 1; 606122702Sandredrop: 607122702Sandre if (m) 608122702Sandre m_freem(m); 609128872Sandre if (ro.ro_rt) 610128872Sandre RTFREE(ro.ro_rt); 611122702Sandre return 1; 612122702Sandre} 613