Annotation of sys/netinet/ip_gre.c, Revision 1.1
1.1 ! nbrk 1: /* $OpenBSD: ip_gre.c,v 1.31 2007/05/27 21:20:52 claudio Exp $ */
! 2: /* $NetBSD: ip_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: * Redistribution and use in source and binary forms, with or without
! 12: * modification, are permitted provided that the following conditions
! 13: * are met:
! 14: * 1. Redistributions of source code must retain the above copyright
! 15: * notice, this list of conditions and the following disclaimer.
! 16: * 2. Redistributions in binary form must reproduce the above copyright
! 17: * notice, this list of conditions and the following disclaimer in the
! 18: * documentation and/or other materials provided with the distribution.
! 19: * 3. All advertising materials mentioning features or use of this software
! 20: * must display the following acknowledgement:
! 21: * This product includes software developed by the NetBSD
! 22: * Foundation, Inc. and its contributors.
! 23: * 4. Neither the name of The NetBSD Foundation nor the names of its
! 24: * contributors may be used to endorse or promote products derived
! 25: * from this software without specific prior written permission.
! 26: *
! 27: * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
! 28: * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
! 29: * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
! 30: * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
! 31: * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
! 32: * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
! 33: * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
! 34: * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
! 35: * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
! 36: * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
! 37: * POSSIBILITY OF SUCH DAMAGE.
! 38: */
! 39:
! 40: /*
! 41: * decapsulate tunneled packets and send them on
! 42: * output half is in net/if_gre.[ch]
! 43: * This currently handles IPPROTO_GRE, IPPROTO_MOBILE
! 44: */
! 45:
! 46:
! 47: #include "gre.h"
! 48: #if NGRE > 0
! 49:
! 50: #include <sys/param.h>
! 51: #include <sys/systm.h>
! 52: #include <sys/mbuf.h>
! 53: #include <sys/socket.h>
! 54: #include <sys/sysctl.h>
! 55: #include <net/if.h>
! 56: #include <net/netisr.h>
! 57: #include <net/route.h>
! 58: #include <net/bpf.h>
! 59:
! 60: #ifdef INET
! 61: #include <netinet/in.h>
! 62: #include <netinet/in_var.h>
! 63: #include <netinet/in_systm.h>
! 64: #include <netinet/ip.h>
! 65: #include <netinet/ip_var.h>
! 66: #include <netinet/ip_gre.h>
! 67: #include <netinet/if_ether.h>
! 68: #else
! 69: #error "ip_gre used without inet"
! 70: #endif
! 71:
! 72: #ifdef NETATALK
! 73: #include <netatalk/at.h>
! 74: #include <netatalk/at_var.h>
! 75: #include <netatalk/at_extern.h>
! 76: #endif
! 77:
! 78: #include "bpfilter.h"
! 79:
! 80: /* Needs IP headers. */
! 81: #include <net/if_gre.h>
! 82:
! 83: struct gre_softc *gre_lookup(struct mbuf *, u_int8_t);
! 84: int gre_input2(struct mbuf *, int, u_char);
! 85:
! 86: /*
! 87: * Decapsulate.
! 88: * Does the real work and is called from gre_input() (above)
! 89: * returns 0 if packet is not yet processed
! 90: * and 1 if it needs no further processing
! 91: * proto is the protocol number of the "calling" foo_input()
! 92: * routine.
! 93: */
! 94:
! 95: int
! 96: gre_input2(m , hlen, proto)
! 97: struct mbuf *m;
! 98: int hlen;
! 99: u_char proto;
! 100: {
! 101: struct greip *gip;
! 102: int s;
! 103: struct ifqueue *ifq;
! 104: struct gre_softc *sc;
! 105: u_short flags;
! 106: u_int af;
! 107:
! 108: if ((sc = gre_lookup(m, proto)) == NULL) {
! 109: /* No matching tunnel or tunnel is down. */
! 110: return (0);
! 111: }
! 112:
! 113: if (m->m_len < sizeof(*gip)) {
! 114: m = m_pullup(m, sizeof(*gip));
! 115: if (m == NULL)
! 116: return (ENOBUFS);
! 117: }
! 118: gip = mtod(m, struct greip *);
! 119:
! 120: m->m_pkthdr.rcvif = &sc->sc_if;
! 121:
! 122: sc->sc_if.if_ipackets++;
! 123: sc->sc_if.if_ibytes += m->m_pkthdr.len;
! 124:
! 125: switch (proto) {
! 126: case IPPROTO_GRE:
! 127: hlen += sizeof (struct gre_h);
! 128:
! 129: /* process GRE flags as packet can be of variable len */
! 130: flags = ntohs(gip->gi_flags);
! 131:
! 132: /* Checksum & Offset are present */
! 133: if ((flags & GRE_CP) | (flags & GRE_RP))
! 134: hlen += 4;
! 135:
! 136: /* We don't support routing fields (variable length) */
! 137: if (flags & GRE_RP)
! 138: return (0);
! 139:
! 140: if (flags & GRE_KP)
! 141: hlen += 4;
! 142:
! 143: if (flags & GRE_SP)
! 144: hlen += 4;
! 145:
! 146: switch (ntohs(gip->gi_ptype)) { /* ethertypes */
! 147: case GREPROTO_WCCP:
! 148: /* WCCP/GRE:
! 149: * So far as I can see (and test) it seems that Cisco's WCCP
! 150: * GRE tunnel is precisely a IP-in-GRE tunnel that differs
! 151: * only in its protocol number. At least, it works for me.
! 152: *
! 153: * The Internet Draft can be found if you look for
! 154: * draft-forster-wrec-wccp-v1-00.txt
! 155: *
! 156: * So yes, we're doing a fall-through (unless, of course,
! 157: * net.inet.gre.wccp is 0).
! 158: */
! 159: if (!gre_wccp)
! 160: return (0);
! 161: case ETHERTYPE_IP: /* shouldn't need a schednetisr(), as */
! 162: ifq = &ipintrq; /* we are in ip_input */
! 163: af = AF_INET;
! 164: break;
! 165: #ifdef NETATALK
! 166: case ETHERTYPE_AT:
! 167: ifq = &atintrq1;
! 168: schednetisr(NETISR_ATALK);
! 169: af = AF_APPLETALK;
! 170: break;
! 171: #endif
! 172: #ifdef INET6
! 173: case ETHERTYPE_IPV6:
! 174: ifq = &ip6intrq;
! 175: schednetisr(NETISR_IPV6);
! 176: af = AF_INET6;
! 177: break;
! 178: #endif /* INET6 */
! 179: default: /* others not yet supported */
! 180: return (0);
! 181: }
! 182: break;
! 183: default:
! 184: /* others not yet supported */
! 185: return (0);
! 186: }
! 187:
! 188: if (hlen > m->m_pkthdr.len) {
! 189: m_freem(m);
! 190: return (EINVAL);
! 191: }
! 192: m_adj(m, hlen);
! 193:
! 194: #if NBPFILTER > 0
! 195: if (sc->sc_if.if_bpf)
! 196: bpf_mtap_af(sc->sc_if.if_bpf, af, m, BPF_DIRECTION_IN);
! 197: #endif
! 198:
! 199: s = splnet(); /* possible */
! 200: IF_INPUT_ENQUEUE(ifq, m);
! 201: splx(s);
! 202:
! 203: return (1); /* packet is done, no further processing needed */
! 204: }
! 205:
! 206: /*
! 207: * Decapsulate a packet and feed it back through ip_input (this
! 208: * routine is called whenever IP gets a packet with proto type
! 209: * IPPROTO_GRE and a local destination address).
! 210: */
! 211: void
! 212: gre_input(struct mbuf *m, ...)
! 213: {
! 214: int hlen, ret;
! 215: va_list ap;
! 216:
! 217: va_start(ap, m);
! 218: hlen = va_arg(ap, int);
! 219: va_end(ap);
! 220:
! 221: if (!gre_allow) {
! 222: m_freem(m);
! 223: return;
! 224: }
! 225:
! 226: ret = gre_input2(m, hlen, IPPROTO_GRE);
! 227: /*
! 228: * ret == 0: packet not processed, but input from here
! 229: * means no matching tunnel that is up is found.
! 230: * we inject it to raw ip socket to see if anyone picks it up.
! 231: * possible that we received a WCCPv1-style GRE packet
! 232: * but we're not set to accept them.
! 233: */
! 234: if (!ret)
! 235: rip_input(m, hlen, IPPROTO_GRE);
! 236: }
! 237:
! 238: /*
! 239: * Input routine for IPPRPOTO_MOBILE.
! 240: * This is a little bit diffrent from the other modes, as the
! 241: * encapsulating header was not prepended, but instead inserted
! 242: * between IP header and payload.
! 243: */
! 244:
! 245: void
! 246: gre_mobile_input(struct mbuf *m, ...)
! 247: {
! 248: struct ip *ip;
! 249: struct mobip_h *mip;
! 250: struct ifqueue *ifq;
! 251: struct gre_softc *sc;
! 252: int hlen, s;
! 253: va_list ap;
! 254: u_char osrc = 0;
! 255: int msiz;
! 256:
! 257: va_start(ap, m);
! 258: hlen = va_arg(ap, int);
! 259: va_end(ap);
! 260:
! 261: if (!ip_mobile_allow) {
! 262: m_freem(m);
! 263: return;
! 264: }
! 265:
! 266: if ((sc = gre_lookup(m, IPPROTO_MOBILE)) == NULL) {
! 267: /* No matching tunnel or tunnel is down. */
! 268: m_freem(m);
! 269: return;
! 270: }
! 271:
! 272: if (m->m_len < sizeof(*mip)) {
! 273: m = m_pullup(m, sizeof(*mip));
! 274: if (m == NULL)
! 275: return;
! 276: }
! 277: ip = mtod(m, struct ip *);
! 278: mip = mtod(m, struct mobip_h *);
! 279:
! 280: m->m_pkthdr.rcvif = &sc->sc_if;
! 281:
! 282: sc->sc_if.if_ipackets++;
! 283: sc->sc_if.if_ibytes += m->m_pkthdr.len;
! 284:
! 285: if (ntohs(mip->mh.proto) & MOB_H_SBIT) {
! 286: osrc = 1;
! 287: msiz = MOB_H_SIZ_L;
! 288: mip->mi.ip_src.s_addr = mip->mh.osrc;
! 289: } else
! 290: msiz = MOB_H_SIZ_S;
! 291:
! 292: if (m->m_len < (ip->ip_hl << 2) + msiz) {
! 293: m = m_pullup(m, (ip->ip_hl << 2) + msiz);
! 294: if (m == NULL)
! 295: return;
! 296: ip = mtod(m, struct ip *);
! 297: mip = mtod(m, struct mobip_h *);
! 298: }
! 299:
! 300: mip->mi.ip_dst.s_addr = mip->mh.odst;
! 301: mip->mi.ip_p = (ntohs(mip->mh.proto) >> 8);
! 302:
! 303: if (gre_in_cksum((u_short *) &mip->mh, msiz) != 0) {
! 304: m_freem(m);
! 305: return;
! 306: }
! 307:
! 308: bcopy(ip + (ip->ip_hl << 2) + msiz, ip + (ip->ip_hl << 2),
! 309: m->m_len - msiz - (ip->ip_hl << 2));
! 310:
! 311: m->m_len -= msiz;
! 312: ip->ip_len = htons(ntohs(ip->ip_len) - msiz);
! 313: m->m_pkthdr.len -= msiz;
! 314:
! 315: ip->ip_sum = 0;
! 316: ip->ip_sum = in_cksum(m,(ip->ip_hl << 2));
! 317:
! 318: ifq = &ipintrq;
! 319:
! 320: #if NBPFILTER > 0
! 321: if (sc->sc_if.if_bpf)
! 322: bpf_mtap_af(sc->sc_if.if_bpf, AF_INET, m, BPF_DIRECTION_IN);
! 323: #endif
! 324:
! 325: s = splnet(); /* possible */
! 326: IF_INPUT_ENQUEUE(ifq, m);
! 327: splx(s);
! 328: }
! 329:
! 330: /*
! 331: * Find the gre interface associated with our src/dst/proto set.
! 332: */
! 333: struct gre_softc *
! 334: gre_lookup(m, proto)
! 335: struct mbuf *m;
! 336: u_int8_t proto;
! 337: {
! 338: struct ip *ip = mtod(m, struct ip *);
! 339: struct gre_softc *sc;
! 340:
! 341: LIST_FOREACH(sc, &gre_softc_list, sc_list) {
! 342: if ((sc->g_dst.s_addr == ip->ip_src.s_addr) &&
! 343: (sc->g_src.s_addr == ip->ip_dst.s_addr) &&
! 344: (sc->g_proto == proto) &&
! 345: ((sc->sc_if.if_flags & IFF_UP) != 0))
! 346: return (sc);
! 347: }
! 348:
! 349: return (NULL);
! 350: }
! 351:
! 352: int
! 353: gre_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
! 354: int *name;
! 355: u_int namelen;
! 356: void *oldp;
! 357: size_t *oldlenp;
! 358: void *newp;
! 359: size_t newlen;
! 360: {
! 361: /* All sysctl names at this level are terminal. */
! 362: if (namelen != 1)
! 363: return (ENOTDIR);
! 364:
! 365: switch (name[0]) {
! 366: case GRECTL_ALLOW:
! 367: return (sysctl_int(oldp, oldlenp, newp, newlen, &gre_allow));
! 368: case GRECTL_WCCP:
! 369: return (sysctl_int(oldp, oldlenp, newp, newlen, &gre_wccp));
! 370: default:
! 371: return (ENOPROTOOPT);
! 372: }
! 373: /* NOTREACHED */
! 374: }
! 375:
! 376: int
! 377: ipmobile_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
! 378: int *name;
! 379: u_int namelen;
! 380: void *oldp;
! 381: size_t *oldlenp;
! 382: void *newp;
! 383: size_t newlen;
! 384: {
! 385: /* All sysctl names at this level are terminal. */
! 386: if (namelen != 1)
! 387: return (ENOTDIR);
! 388:
! 389: switch (name[0]) {
! 390: case MOBILEIPCTL_ALLOW:
! 391: return (sysctl_int(oldp, oldlenp, newp, newlen,
! 392: &ip_mobile_allow));
! 393: default:
! 394: return (ENOPROTOOPT);
! 395: }
! 396: /* NOTREACHED */
! 397: }
! 398: #endif /* if NGRE > 0 */
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