1 /* $OpenBSD: if_gre.c,v 1.58 2012/04/14 09:39:47 yasuoka Exp $ */ 2 /* $NetBSD: if_gre.c,v 1.9 1999/10/25 19:18:11 drochner Exp $ */ 3 4 /* 5 * Copyright (c) 1998 The NetBSD Foundation, Inc. 6 * All rights reserved. 7 * 8 * This code is derived from software contributed to The NetBSD Foundation 9 * by Heiko W.Rupp <hwr@pilhuhn.de> 10 * 11 * IPv6-over-GRE contributed by Gert Doering <gert@greenie.muc.de> 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 23 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 24 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 25 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 26 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 27 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 28 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 29 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 30 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 31 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 32 * POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 /* 36 * Encapsulate L3 protocols into IP, per RFC 1701 and 1702. 37 * See gre(4) for more details. 38 * Also supported: IP in IP encapsulation (proto 55) per RFC 2004. 39 */ 40 41 #include "gre.h" 42 #if NGRE > 0 43 44 #include "bpfilter.h" 45 #include "pf.h" 46 47 #include <sys/param.h> 48 #include <sys/proc.h> 49 #include <sys/mbuf.h> 50 #include <sys/socket.h> 51 #include <sys/sockio.h> 52 #include <sys/kernel.h> 53 #include <sys/systm.h> 54 55 #include <net/if.h> 56 #include <net/if_types.h> 57 #include <net/netisr.h> 58 #include <net/route.h> 59 60 #ifdef INET 61 #include <netinet/in.h> 62 #include <netinet/in_systm.h> 63 #include <netinet/in_var.h> 64 #include <netinet/ip.h> 65 #include <netinet/ip_var.h> 66 #include <netinet/if_ether.h> 67 #else 68 #error "if_gre used without inet" 69 #endif 70 71 #if NBPFILTER > 0 72 #include <net/bpf.h> 73 #endif 74 75 #if NPF > 0 76 #include <net/pfvar.h> 77 #endif 78 79 #include <net/if_gre.h> 80 81 #ifndef GRE_RECURSION_LIMIT 82 #define GRE_RECURSION_LIMIT 3 /* How many levels of recursion allowed */ 83 #endif /* GRE_RECURSION_LIMIT */ 84 85 /* 86 * It is not easy to calculate the right value for a GRE MTU. 87 * We leave this task to the admin and use the same default that 88 * other vendors use. 89 */ 90 #define GREMTU 1476 91 92 int gre_clone_create(struct if_clone *, int); 93 int gre_clone_destroy(struct ifnet *); 94 95 struct gre_softc_head gre_softc_list; 96 struct if_clone gre_cloner = 97 IF_CLONE_INITIALIZER("gre", gre_clone_create, gre_clone_destroy); 98 99 /* 100 * We can control the acceptance of GRE and MobileIP packets by 101 * altering the sysctl net.inet.gre.allow and net.inet.mobileip.allow values 102 * respectively. Zero means drop them, all else is acceptance. We can also 103 * control acceptance of WCCPv1-style GRE packets through the 104 * net.inet.gre.wccp value, but be aware it depends upon normal GRE being 105 * allowed as well. 106 * 107 */ 108 int gre_allow = 0; 109 int gre_wccp = 0; 110 int ip_mobile_allow = 0; 111 112 void gre_keepalive(void *); 113 void gre_send_keepalive(void *); 114 void gre_link_state(struct gre_softc *); 115 116 void 117 greattach(int n) 118 { 119 LIST_INIT(&gre_softc_list); 120 if_clone_attach(&gre_cloner); 121 } 122 123 int 124 gre_clone_create(struct if_clone *ifc, int unit) 125 { 126 struct gre_softc *sc; 127 int s; 128 129 sc = malloc(sizeof(*sc), M_DEVBUF, M_NOWAIT|M_ZERO); 130 if (!sc) 131 return (ENOMEM); 132 snprintf(sc->sc_if.if_xname, sizeof sc->sc_if.if_xname, "%s%d", 133 ifc->ifc_name, unit); 134 sc->sc_if.if_softc = sc; 135 sc->sc_if.if_type = IFT_TUNNEL; 136 sc->sc_if.if_addrlen = 0; 137 sc->sc_if.if_hdrlen = 24; /* IP + GRE */ 138 sc->sc_if.if_mtu = GREMTU; 139 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST; 140 sc->sc_if.if_output = gre_output; 141 sc->sc_if.if_ioctl = gre_ioctl; 142 sc->sc_if.if_collisions = 0; 143 sc->sc_if.if_ierrors = 0; 144 sc->sc_if.if_oerrors = 0; 145 sc->sc_if.if_ipackets = 0; 146 sc->sc_if.if_opackets = 0; 147 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY; 148 sc->g_proto = IPPROTO_GRE; 149 sc->sc_if.if_flags |= IFF_LINK0; 150 sc->sc_ka_state = GRE_STATE_UKNWN; 151 152 timeout_set(&sc->sc_ka_hold, gre_keepalive, sc); 153 timeout_set(&sc->sc_ka_snd, gre_send_keepalive, sc); 154 155 if_attach(&sc->sc_if); 156 if_alloc_sadl(&sc->sc_if); 157 158 #if NBPFILTER > 0 159 bpfattach(&sc->sc_if.if_bpf, &sc->sc_if, DLT_LOOP, sizeof(u_int32_t)); 160 #endif 161 s = splnet(); 162 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list); 163 splx(s); 164 165 return (0); 166 } 167 168 int 169 gre_clone_destroy(struct ifnet *ifp) 170 { 171 struct gre_softc *sc = ifp->if_softc; 172 int s; 173 174 s = splnet(); 175 timeout_del(&sc->sc_ka_snd); 176 timeout_del(&sc->sc_ka_hold); 177 LIST_REMOVE(sc, sc_list); 178 splx(s); 179 180 if_detach(ifp); 181 182 free(sc, M_DEVBUF); 183 return (0); 184 } 185 186 /* 187 * The output routine. Takes a packet and encapsulates it in the protocol 188 * given by sc->g_proto. See also RFC 1701 and RFC 2004. 189 */ 190 191 int 192 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 193 struct rtentry *rt) 194 { 195 int error = 0; 196 struct gre_softc *sc = (struct gre_softc *) (ifp->if_softc); 197 struct greip *gh = NULL; 198 struct ip *inp = NULL; 199 u_int8_t ip_tos = 0; 200 u_int16_t etype = 0; 201 struct mobile_h mob_h; 202 struct m_tag *mtag; 203 204 if ((ifp->if_flags & IFF_UP) == 0 || 205 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) { 206 m_freem(m); 207 error = ENETDOWN; 208 goto end; 209 } 210 211 #ifdef DIAGNOSTIC 212 if (ifp->if_rdomain != rtable_l2(m->m_pkthdr.rdomain)) { 213 printf("%s: trying to send packet on wrong domain. " 214 "if %d vs. mbuf %d, AF %d\n", ifp->if_xname, 215 ifp->if_rdomain, rtable_l2(m->m_pkthdr.rdomain), 216 dst->sa_family); 217 } 218 #endif 219 220 /* Try to limit infinite recursion through misconfiguration. */ 221 for (mtag = m_tag_find(m, PACKET_TAG_GRE, NULL); mtag; 222 mtag = m_tag_find(m, PACKET_TAG_GRE, mtag)) { 223 if (!bcmp((caddr_t)(mtag + 1), &ifp, sizeof(struct ifnet *))) { 224 IF_DROP(&ifp->if_snd); 225 m_freem(m); 226 error = EIO; 227 goto end; 228 } 229 } 230 231 mtag = m_tag_get(PACKET_TAG_GRE, sizeof(struct ifnet *), M_NOWAIT); 232 if (mtag == NULL) { 233 IF_DROP(&ifp->if_snd); 234 m_freem(m); 235 error = ENOBUFS; 236 goto end; 237 } 238 bcopy(&ifp, (caddr_t)(mtag + 1), sizeof(struct ifnet *)); 239 m_tag_prepend(m, mtag); 240 241 m->m_flags &= ~(M_BCAST|M_MCAST); 242 243 #if NBPFILTER > 0 244 if (ifp->if_bpf) 245 bpf_mtap_af(ifp->if_bpf, dst->sa_family, m, BPF_DIRECTION_OUT); 246 #endif 247 248 if (sc->g_proto == IPPROTO_MOBILE) { 249 if (ip_mobile_allow == 0) { 250 IF_DROP(&ifp->if_snd); 251 m_freem(m); 252 error = EACCES; 253 goto end; 254 } 255 256 if (dst->sa_family == AF_INET) { 257 struct mbuf *m0; 258 int msiz; 259 260 /* 261 * Make sure the complete IP header (with options) 262 * is in the first mbuf. 263 */ 264 if (m->m_len < sizeof(struct ip)) { 265 m = m_pullup(m, sizeof(struct ip)); 266 if (m == NULL) { 267 IF_DROP(&ifp->if_snd); 268 error = ENOBUFS; 269 goto end; 270 } else 271 inp = mtod(m, struct ip *); 272 273 if (m->m_len < inp->ip_hl << 2) { 274 m = m_pullup(m, inp->ip_hl << 2); 275 if (m == NULL) { 276 IF_DROP(&ifp->if_snd); 277 error = ENOBUFS; 278 goto end; 279 } 280 } 281 } 282 283 inp = mtod(m, struct ip *); 284 285 bzero(&mob_h, MOB_H_SIZ_L); 286 mob_h.proto = (inp->ip_p) << 8; 287 mob_h.odst = inp->ip_dst.s_addr; 288 inp->ip_dst.s_addr = sc->g_dst.s_addr; 289 290 /* 291 * If the packet comes from our host, we only change 292 * the destination address in the IP header. 293 * Otherwise we need to save and change the source. 294 */ 295 if (inp->ip_src.s_addr == sc->g_src.s_addr) { 296 msiz = MOB_H_SIZ_S; 297 } else { 298 mob_h.proto |= MOB_H_SBIT; 299 mob_h.osrc = inp->ip_src.s_addr; 300 inp->ip_src.s_addr = sc->g_src.s_addr; 301 msiz = MOB_H_SIZ_L; 302 } 303 304 HTONS(mob_h.proto); 305 mob_h.hcrc = gre_in_cksum((u_int16_t *) &mob_h, msiz); 306 307 /* Squeeze in the mobility header */ 308 if ((m->m_data - msiz) < m->m_pktdat) { 309 /* Need new mbuf */ 310 MGETHDR(m0, M_DONTWAIT, MT_HEADER); 311 if (m0 == NULL) { 312 IF_DROP(&ifp->if_snd); 313 m_freem(m); 314 error = ENOBUFS; 315 goto end; 316 } 317 M_MOVE_HDR(m0, m); 318 319 m0->m_len = msiz + (inp->ip_hl << 2); 320 m0->m_data += max_linkhdr; 321 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 322 m->m_data += inp->ip_hl << 2; 323 m->m_len -= inp->ip_hl << 2; 324 325 bcopy((caddr_t) inp, mtod(m0, caddr_t), 326 sizeof(struct ip)); 327 328 m0->m_next = m; 329 m = m0; 330 } else { /* we have some space left in the old one */ 331 m->m_data -= msiz; 332 m->m_len += msiz; 333 m->m_pkthdr.len += msiz; 334 bcopy(inp, mtod(m, caddr_t), 335 inp->ip_hl << 2); 336 } 337 338 /* Copy Mobility header */ 339 inp = mtod(m, struct ip *); 340 bcopy(&mob_h, (caddr_t)(inp + 1), (unsigned) msiz); 341 inp->ip_len = htons(ntohs(inp->ip_len) + msiz); 342 } else { /* AF_INET */ 343 IF_DROP(&ifp->if_snd); 344 m_freem(m); 345 error = EINVAL; 346 goto end; 347 } 348 } else if (sc->g_proto == IPPROTO_GRE) { 349 if (gre_allow == 0) { 350 IF_DROP(&ifp->if_snd); 351 m_freem(m); 352 error = EACCES; 353 goto end; 354 } 355 356 switch(dst->sa_family) { 357 case AF_INET: 358 if (m->m_len < sizeof(struct ip)) { 359 m = m_pullup(m, sizeof(struct ip)); 360 if (m == NULL) { 361 IF_DROP(&ifp->if_snd); 362 error = ENOBUFS; 363 goto end; 364 } 365 } 366 367 inp = mtod(m, struct ip *); 368 ip_tos = inp->ip_tos; 369 etype = ETHERTYPE_IP; 370 break; 371 #ifdef INET6 372 case AF_INET6: 373 etype = ETHERTYPE_IPV6; 374 break; 375 #endif 376 #ifdef MPLS 377 case AF_MPLS: 378 if (m->m_flags & (M_BCAST | M_MCAST)) 379 etype = ETHERTYPE_MPLS_MCAST; 380 else 381 etype = ETHERTYPE_MPLS; 382 break; 383 #endif 384 default: 385 IF_DROP(&ifp->if_snd); 386 m_freem(m); 387 error = EAFNOSUPPORT; 388 goto end; 389 } 390 391 M_PREPEND(m, sizeof(struct greip), M_DONTWAIT); 392 } else { 393 IF_DROP(&ifp->if_snd); 394 m_freem(m); 395 error = EINVAL; 396 goto end; 397 } 398 399 if (m == NULL) { 400 IF_DROP(&ifp->if_snd); 401 error = ENOBUFS; 402 goto end; 403 } 404 405 gh = mtod(m, struct greip *); 406 if (sc->g_proto == IPPROTO_GRE) { 407 /* We don't support any GRE flags for now */ 408 409 bzero((void *) &gh->gi_g, sizeof(struct gre_h)); 410 gh->gi_ptype = htons(etype); 411 } 412 413 gh->gi_pr = sc->g_proto; 414 if (sc->g_proto != IPPROTO_MOBILE) { 415 gh->gi_src = sc->g_src; 416 gh->gi_dst = sc->g_dst; 417 ((struct ip *) gh)->ip_hl = (sizeof(struct ip)) >> 2; 418 ((struct ip *) gh)->ip_ttl = ip_defttl; 419 ((struct ip *) gh)->ip_tos = ip_tos; 420 gh->gi_len = htons(m->m_pkthdr.len); 421 } 422 423 ifp->if_opackets++; 424 ifp->if_obytes += m->m_pkthdr.len; 425 426 427 m->m_pkthdr.rdomain = sc->g_rtableid; 428 429 #if NPF > 0 430 pf_pkt_addr_changed(m); 431 #endif 432 433 /* Send it off */ 434 error = ip_output(m, (void *)NULL, &sc->route, 0, (void *)NULL, (void *)NULL); 435 end: 436 if (error) 437 ifp->if_oerrors++; 438 return (error); 439 } 440 441 int 442 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 443 { 444 445 struct ifreq *ifr = (struct ifreq *) data; 446 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 447 struct ifkalivereq *ikar = (struct ifkalivereq *)data; 448 struct gre_softc *sc = ifp->if_softc; 449 int s; 450 struct sockaddr_in si; 451 struct sockaddr *sa = NULL; 452 int error = 0; 453 struct proc *prc = curproc; /* XXX */ 454 455 s = splnet(); 456 switch(cmd) { 457 case SIOCSIFADDR: 458 ifp->if_flags |= IFF_UP; 459 break; 460 case SIOCSIFDSTADDR: 461 break; 462 case SIOCSIFFLAGS: 463 if ((ifr->ifr_flags & IFF_LINK0) != 0) 464 sc->g_proto = IPPROTO_GRE; 465 else 466 sc->g_proto = IPPROTO_MOBILE; 467 break; 468 case SIOCSIFMTU: 469 if (ifr->ifr_mtu < 576) { 470 error = EINVAL; 471 break; 472 } 473 ifp->if_mtu = ifr->ifr_mtu; 474 break; 475 case SIOCGIFMTU: 476 ifr->ifr_mtu = sc->sc_if.if_mtu; 477 break; 478 case SIOCADDMULTI: 479 case SIOCDELMULTI: 480 if (ifr == 0) { 481 error = EAFNOSUPPORT; 482 break; 483 } 484 switch (ifr->ifr_addr.sa_family) { 485 #ifdef INET 486 case AF_INET: 487 break; 488 #endif 489 #ifdef INET6 490 case AF_INET6: 491 break; 492 #endif 493 default: 494 error = EAFNOSUPPORT; 495 break; 496 } 497 break; 498 case GRESPROTO: 499 /* Check for superuser */ 500 if ((error = suser(prc, 0)) != 0) 501 break; 502 503 sc->g_proto = ifr->ifr_flags; 504 switch (sc->g_proto) { 505 case IPPROTO_GRE: 506 ifp->if_flags |= IFF_LINK0; 507 break; 508 case IPPROTO_MOBILE: 509 ifp->if_flags &= ~IFF_LINK0; 510 break; 511 default: 512 error = EPROTONOSUPPORT; 513 break; 514 } 515 break; 516 case GREGPROTO: 517 ifr->ifr_flags = sc->g_proto; 518 break; 519 case GRESADDRS: 520 case GRESADDRD: 521 /* Check for superuser */ 522 if ((error = suser(prc, 0)) != 0) 523 break; 524 525 /* 526 * set tunnel endpoints and mark if as up 527 */ 528 sa = &ifr->ifr_addr; 529 if (cmd == GRESADDRS ) 530 sc->g_src = (satosin(sa))->sin_addr; 531 if (cmd == GRESADDRD ) 532 sc->g_dst = (satosin(sa))->sin_addr; 533 recompute: 534 if ((sc->g_src.s_addr != INADDR_ANY) && 535 (sc->g_dst.s_addr != INADDR_ANY)) { 536 if (sc->route.ro_rt != 0) 537 RTFREE(sc->route.ro_rt); 538 /* ip_output() will do the lookup */ 539 bzero(&sc->route, sizeof(sc->route)); 540 ifp->if_flags |= IFF_UP; 541 } 542 break; 543 case GREGADDRS: 544 bzero(&si, sizeof(si)); 545 si.sin_family = AF_INET; 546 si.sin_len = sizeof(struct sockaddr_in); 547 si.sin_addr.s_addr = sc->g_src.s_addr; 548 sa = sintosa(&si); 549 ifr->ifr_addr = *sa; 550 break; 551 case GREGADDRD: 552 bzero(&si, sizeof(si)); 553 si.sin_family = AF_INET; 554 si.sin_len = sizeof(struct sockaddr_in); 555 si.sin_addr.s_addr = sc->g_dst.s_addr; 556 sa = sintosa(&si); 557 ifr->ifr_addr = *sa; 558 break; 559 case SIOCSETKALIVE: 560 if ((error = suser(prc, 0)) != 0) 561 break; 562 if (ikar->ikar_timeo < 0 || ikar->ikar_timeo > 86400 || 563 ikar->ikar_cnt < 0 || ikar->ikar_cnt > 256) { 564 error = EINVAL; 565 break; 566 } 567 sc->sc_ka_timout = ikar->ikar_timeo; 568 sc->sc_ka_cnt = ikar->ikar_cnt; 569 if (sc->sc_ka_timout == 0 || sc->sc_ka_cnt == 0) { 570 sc->sc_ka_timout = 0; 571 sc->sc_ka_cnt = 0; 572 sc->sc_ka_state = GRE_STATE_UKNWN; 573 gre_link_state(sc); 574 break; 575 } 576 if (!timeout_pending(&sc->sc_ka_snd)) { 577 sc->sc_ka_holdmax = sc->sc_ka_cnt; 578 timeout_add(&sc->sc_ka_snd, 1); 579 timeout_add_sec(&sc->sc_ka_hold, sc->sc_ka_timout * 580 sc->sc_ka_cnt); 581 } 582 break; 583 case SIOCGETKALIVE: 584 ikar->ikar_timeo = sc->sc_ka_timout; 585 ikar->ikar_cnt = sc->sc_ka_cnt; 586 break; 587 case SIOCSLIFPHYADDR: 588 if ((error = suser(prc, 0)) != 0) 589 break; 590 if (lifr->addr.ss_family != AF_INET || 591 lifr->dstaddr.ss_family != AF_INET) { 592 error = EAFNOSUPPORT; 593 break; 594 } 595 if (lifr->addr.ss_len != sizeof(si) || 596 lifr->dstaddr.ss_len != sizeof(si)) { 597 error = EINVAL; 598 break; 599 } 600 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; 601 sc->g_dst = 602 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; 603 goto recompute; 604 case SIOCDIFPHYADDR: 605 if ((error = suser(prc, 0)) != 0) 606 break; 607 sc->g_src.s_addr = INADDR_ANY; 608 sc->g_dst.s_addr = INADDR_ANY; 609 break; 610 case SIOCGLIFPHYADDR: 611 if (sc->g_src.s_addr == INADDR_ANY || 612 sc->g_dst.s_addr == INADDR_ANY) { 613 error = EADDRNOTAVAIL; 614 break; 615 } 616 bzero(&si, sizeof(si)); 617 si.sin_family = AF_INET; 618 si.sin_len = sizeof(struct sockaddr_in); 619 si.sin_addr.s_addr = sc->g_src.s_addr; 620 memcpy(&lifr->addr, &si, sizeof(si)); 621 si.sin_addr.s_addr = sc->g_dst.s_addr; 622 memcpy(&lifr->dstaddr, &si, sizeof(si)); 623 break; 624 case SIOCSLIFPHYRTABLE: 625 if ((error = suser(prc, 0)) != 0) 626 break; 627 if (ifr->ifr_rdomainid < 0 || 628 ifr->ifr_rdomainid > RT_TABLEID_MAX || 629 !rtable_exists(ifr->ifr_rdomainid)) { 630 error = EINVAL; 631 break; 632 } 633 sc->g_rtableid = ifr->ifr_rdomainid; 634 goto recompute; 635 case SIOCGLIFPHYRTABLE: 636 ifr->ifr_rdomainid = sc->g_rtableid; 637 break; 638 default: 639 error = ENOTTY; 640 } 641 642 splx(s); 643 return (error); 644 } 645 646 /* 647 * do a checksum of a buffer - much like in_cksum, which operates on 648 * mbufs. 649 */ 650 u_int16_t 651 gre_in_cksum(u_int16_t *p, u_int len) 652 { 653 u_int32_t sum = 0; 654 int nwords = len >> 1; 655 656 while (nwords-- != 0) 657 sum += *p++; 658 659 if (len & 1) { 660 union { 661 u_short w; 662 u_char c[2]; 663 } u; 664 u.c[0] = *(u_char *) p; 665 u.c[1] = 0; 666 sum += u.w; 667 } 668 669 /* end-around-carry */ 670 sum = (sum >> 16) + (sum & 0xffff); 671 sum += (sum >> 16); 672 return (~sum); 673 } 674 675 void 676 gre_keepalive(void *arg) 677 { 678 struct gre_softc *sc = arg; 679 680 if (!sc->sc_ka_timout) 681 return; 682 683 sc->sc_ka_state = GRE_STATE_DOWN; 684 gre_link_state(sc); 685 } 686 687 void 688 gre_send_keepalive(void *arg) 689 { 690 struct gre_softc *sc = arg; 691 struct mbuf *m; 692 struct ip *ip; 693 struct gre_h *gh; 694 struct sockaddr dst; 695 int s; 696 697 if (sc->sc_ka_timout) 698 timeout_add_sec(&sc->sc_ka_snd, sc->sc_ka_timout); 699 700 if (sc->g_proto != IPPROTO_GRE) 701 return; 702 if ((sc->sc_if.if_flags & IFF_UP) == 0 || 703 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) 704 return; 705 706 MGETHDR(m, M_DONTWAIT, MT_DATA); 707 if (m == NULL) { 708 sc->sc_if.if_oerrors++; 709 return; 710 } 711 712 m->m_len = m->m_pkthdr.len = sizeof(*ip) + sizeof(*gh); 713 MH_ALIGN(m, m->m_len); 714 715 /* build the ip header */ 716 ip = mtod(m, struct ip *); 717 718 ip->ip_v = IPVERSION; 719 ip->ip_hl = sizeof(*ip) >> 2; 720 ip->ip_tos = IPTOS_LOWDELAY; 721 ip->ip_len = htons(m->m_pkthdr.len); 722 ip->ip_id = htons(ip_randomid()); 723 ip->ip_off = htons(IP_DF); 724 ip->ip_ttl = ip_defttl; 725 ip->ip_p = IPPROTO_GRE; 726 ip->ip_src.s_addr = sc->g_dst.s_addr; 727 ip->ip_dst.s_addr = sc->g_src.s_addr; 728 ip->ip_sum = 0; 729 ip->ip_sum = in_cksum(m, sizeof(*ip)); 730 731 gh = (struct gre_h *)(ip + 1); 732 /* We don't support any GRE flags for now */ 733 bzero(gh, sizeof(*gh)); 734 735 bzero(&dst, sizeof(dst)); 736 dst.sa_family = AF_INET; 737 738 s = splsoftnet(); 739 /* should we care about the error? */ 740 gre_output(&sc->sc_if, m, &dst, NULL); 741 splx(s); 742 } 743 744 void 745 gre_recv_keepalive(struct gre_softc *sc) 746 { 747 if (!sc->sc_ka_timout) 748 return; 749 750 /* link state flap dampening */ 751 switch (sc->sc_ka_state) { 752 case GRE_STATE_UKNWN: 753 case GRE_STATE_DOWN: 754 sc->sc_ka_state = GRE_STATE_HOLD; 755 sc->sc_ka_holdcnt = sc->sc_ka_holdmax; 756 sc->sc_ka_holdmax = MIN(sc->sc_ka_holdmax * 2, 757 16 * sc->sc_ka_cnt); 758 break; 759 case GRE_STATE_HOLD: 760 if (--sc->sc_ka_holdcnt < 1) { 761 sc->sc_ka_state = GRE_STATE_UP; 762 gre_link_state(sc); 763 } 764 break; 765 case GRE_STATE_UP: 766 sc->sc_ka_holdmax--; 767 sc->sc_ka_holdmax = MAX(sc->sc_ka_holdmax, sc->sc_ka_cnt); 768 break; 769 } 770 771 /* rescedule hold timer */ 772 timeout_add_sec(&sc->sc_ka_hold, sc->sc_ka_timout * sc->sc_ka_cnt); 773 } 774 775 void 776 gre_link_state(struct gre_softc *sc) 777 { 778 struct ifnet *ifp = &sc->sc_if; 779 int link_state = LINK_STATE_UNKNOWN; 780 781 if (sc->sc_ka_state == GRE_STATE_UP) 782 link_state = LINK_STATE_UP; 783 else if (sc->sc_ka_state != GRE_STATE_UKNWN) 784 link_state = LINK_STATE_KALIVE_DOWN; 785 786 if (ifp->if_link_state != link_state) { 787 ifp->if_link_state = link_state; 788 if_link_state_change(ifp); 789 } 790 } 791 #endif 792