/* * Copyright (c) 2000-2021 Apple Inc. All rights reserved. * * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. The rights granted to you under the License * may not be used to create, or enable the creation or redistribution of, * unlawful or unlicensed copies of an Apple operating system, or to * circumvent, violate, or enable the circumvention or violation of, any * terms of an Apple operating system software license agreement. * * Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ /* $FreeBSD: src/sys/netinet/ip_encap.c,v 1.1.2.2 2001/07/03 11:01:46 ume Exp $ */ /* $KAME: ip_encap.c,v 1.41 2001/03/15 08:35:08 itojun Exp $ */ /* * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the project nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* * My grandfather said that there's a devil inside tunnelling technology... * * We have surprisingly many protocols that want packets with IP protocol * #4 or #41. Here's a list of protocols that want protocol #41: * RFC1933 configured tunnel * RFC1933 automatic tunnel * RFC2401 IPsec tunnel * RFC2473 IPv6 generic packet tunnelling * RFC2529 6over4 tunnel * mobile-ip6 (uses RFC2473) * 6to4 tunnel * Here's a list of protocol that want protocol #4: * RFC1853 IPv4-in-IPv4 tunnelling * RFC2003 IPv4 encapsulation within IPv4 * RFC2344 reverse tunnelling for mobile-ip4 * RFC2401 IPsec tunnel * Well, what can I say. They impose different en/decapsulation mechanism * from each other, so they need separate protocol handler. The only one * we can easily determine by protocol # is IPsec, which always has * AH/ESP header right after outer IP header. * * So, clearly good old protosw does not work for protocol #4 and #41. * The code will let you match protocol via src/dst address pair. */ /* XXX is M_NETADDR correct? */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifndef __APPLE__ #include #include MALLOC_DEFINE(M_NETADDR, "Export Host", "Export host address structure"); #endif static void encap_add_locked(struct encaptab *); static int mask_match(const struct encaptab *, const struct sockaddr *, const struct sockaddr *); static void encap_fillarg(struct mbuf *, void *arg); LIST_HEAD(, encaptab) encaptab = LIST_HEAD_INITIALIZER(&encaptab); static LCK_GRP_DECLARE(encaptab_lock_grp, "encaptab lock"); static LCK_RW_DECLARE(encaptab_lock, &encaptab_lock_grp); #if INET void encap4_input(struct mbuf *m, int off) { int proto; struct ip *ip; struct sockaddr_in s, d; const struct protosw *psw; struct encaptab *ep, *match; int prio, matchprio; void *match_arg = NULL; #ifndef __APPLE__ va_start(ap, m); off = va_arg(ap, int); proto = va_arg(ap, int); va_end(ap); #endif /* Expect 32-bit aligned data pointer on strict-align platforms */ MBUF_STRICT_DATA_ALIGNMENT_CHECK_32(m); ip = mtod(m, struct ip *); #ifdef __APPLE__ proto = ip->ip_p; #endif SOCKADDR_ZERO(&s, sizeof(s)); s.sin_family = AF_INET; s.sin_len = sizeof(struct sockaddr_in); s.sin_addr = ip->ip_src; SOCKADDR_ZERO(&d, sizeof(d)); d.sin_family = AF_INET; d.sin_len = sizeof(struct sockaddr_in); d.sin_addr = ip->ip_dst; match = NULL; matchprio = 0; lck_rw_lock_shared(&encaptab_lock); for (ep = LIST_FIRST(&encaptab); ep; ep = LIST_NEXT(ep, chain)) { if (ep->af != AF_INET) { continue; } if (ep->proto >= 0 && ep->proto != proto) { continue; } if (ep->func) { prio = (*ep->func)(m, off, proto, ep->arg); } else { /* * it's inbound traffic, we need to match in reverse * order */ prio = mask_match(ep, SA(&d), SA(&s)); } /* * We prioritize the matches by using bit length of the * matches. mask_match() and user-supplied matching function * should return the bit length of the matches (for example, * if both src/dst are matched for IPv4, 64 should be returned). * 0 or negative return value means "it did not match". * * The question is, since we have two "mask" portion, we * cannot really define total order between entries. * For example, which of these should be preferred? * mask_match() returns 48 (32 + 16) for both of them. * src=3ffe::/16, dst=3ffe:501::/32 * src=3ffe:501::/32, dst=3ffe::/16 * * We need to loop through all the possible candidates * to get the best match - the search takes O(n) for * n attachments (i.e. interfaces). */ if (prio <= 0) { continue; } if (prio > matchprio) { matchprio = prio; match = ep; psw = (const struct protosw *)match->psw; match_arg = ep->arg; } } lck_rw_unlock_shared(&encaptab_lock); if (match) { /* found a match, "match" has the best one */ if (psw && psw->pr_input) { encap_fillarg(m, match_arg); (*psw->pr_input)(m, off); } else { m_freem(m); } return; } /* last resort: inject to raw socket */ rip_input(m, off); } #endif int encap6_input(struct mbuf **mp, int *offp, int proto) { struct mbuf *m = *mp; struct ip6_hdr *ip6; struct sockaddr_in6 s, d; const struct ip6protosw *psw; struct encaptab *ep, *match; int prio, matchprio; void *match_arg = NULL; /* Expect 32-bit aligned data pointer on strict-align platforms */ MBUF_STRICT_DATA_ALIGNMENT_CHECK_32(m); ip6 = mtod(m, struct ip6_hdr *); SOCKADDR_ZERO(&s, sizeof(s)); s.sin6_family = AF_INET6; s.sin6_len = sizeof(struct sockaddr_in6); s.sin6_addr = ip6->ip6_src; SOCKADDR_ZERO(&d, sizeof(d)); d.sin6_family = AF_INET6; d.sin6_len = sizeof(struct sockaddr_in6); d.sin6_addr = ip6->ip6_dst; match = NULL; matchprio = 0; lck_rw_lock_shared(&encaptab_lock); for (ep = LIST_FIRST(&encaptab); ep; ep = LIST_NEXT(ep, chain)) { if (ep->af != AF_INET6) { continue; } if (ep->proto >= 0 && ep->proto != proto) { continue; } if (ep->func) { prio = (*ep->func)(m, *offp, proto, ep->arg); } else { /* * it's inbound traffic, we need to match in reverse * order */ prio = mask_match(ep, SA(&d), SA(&s)); } /* see encap4_input() for issues here */ if (prio <= 0) { continue; } if (prio > matchprio) { matchprio = prio; match = ep; psw = (const struct ip6protosw *)match->psw; match_arg = ep->arg; } } lck_rw_unlock_shared(&encaptab_lock); if (match) { /* found a match */ if (psw && psw->pr_input) { encap_fillarg(m, match_arg); return (*psw->pr_input)(mp, offp, proto); } else { m_freem(m); return IPPROTO_DONE; } } /* last resort: inject to raw socket */ return rip6_input(mp, offp, proto); } static void encap_add_locked(struct encaptab *ep) { LCK_RW_ASSERT(&encaptab_lock, LCK_RW_ASSERT_EXCLUSIVE); LIST_INSERT_HEAD(&encaptab, ep, chain); } /* * sp (src ptr) is always my side, and dp (dst ptr) is always remote side. * length of mask (sm and dm) is assumed to be same as sp/dp. * Return value will be necessary as input (cookie) for encap_detach(). */ const struct encaptab * encap_attach(int af, int proto, const struct sockaddr *sp, const struct sockaddr *sm, const struct sockaddr *dp, const struct sockaddr *dm, const struct protosw *psw, void *arg) { struct encaptab *ep = NULL; struct encaptab *new_ep = NULL; int error; /* sanity check on args */ if (sp->sa_len > sizeof(new_ep->src) || dp->sa_len > sizeof(new_ep->dst)) { error = EINVAL; goto fail; } if (sp->sa_len != dp->sa_len) { error = EINVAL; goto fail; } if (af != sp->sa_family || af != dp->sa_family) { error = EINVAL; goto fail; } new_ep = kalloc_type(struct encaptab, Z_WAITOK | Z_ZERO | Z_NOFAIL); /* check if anyone have already attached with exactly same config */ lck_rw_lock_exclusive(&encaptab_lock); for (ep = LIST_FIRST(&encaptab); ep; ep = LIST_NEXT(ep, chain)) { if (ep->af != af) { continue; } if (ep->proto != proto) { continue; } if (ep->src.ss_len != sp->sa_len || SOCKADDR_CMP(&ep->src, sp, sp->sa_len) != 0 || SOCKADDR_CMP(&ep->srcmask, sm, sp->sa_len) != 0) { continue; } if (ep->dst.ss_len != dp->sa_len || SOCKADDR_CMP(&ep->dst, dp, dp->sa_len) != 0 || SOCKADDR_CMP(&ep->dstmask, dm, dp->sa_len) != 0) { continue; } error = EEXIST; goto fail_locked; } new_ep->af = af; new_ep->proto = proto; SOCKADDR_COPY(sp, &new_ep->src, sp->sa_len); SOCKADDR_COPY(sm, &new_ep->srcmask, sp->sa_len); SOCKADDR_COPY(dp, &new_ep->dst, dp->sa_len); SOCKADDR_COPY(dm, &new_ep->dstmask, dp->sa_len); new_ep->psw = psw; new_ep->arg = arg; encap_add_locked(new_ep); lck_rw_unlock_exclusive(&encaptab_lock); error = 0; return new_ep; fail_locked: lck_rw_unlock_exclusive(&encaptab_lock); if (new_ep != NULL) { kfree_type(struct encaptab, new_ep); } fail: return NULL; } const struct encaptab * encap_attach_func( int af, int proto, int (*func)(const struct mbuf *, int, int, void *), const struct protosw *psw, void *arg) { struct encaptab *ep; int error; /* sanity check on args */ if (!func) { error = EINVAL; goto fail; } ep = kalloc_type(struct encaptab, Z_WAITOK | Z_ZERO | Z_NOFAIL); /* XXX */ ep->af = af; ep->proto = proto; ep->func = func; ep->psw = psw; ep->arg = arg; lck_rw_lock_exclusive(&encaptab_lock); encap_add_locked(ep); lck_rw_unlock_exclusive(&encaptab_lock); error = 0; return ep; fail: return NULL; } int encap_detach(const struct encaptab *cookie) { const struct encaptab *ep = cookie; struct encaptab *p; lck_rw_lock_exclusive(&encaptab_lock); for (p = LIST_FIRST(&encaptab); p; p = LIST_NEXT(p, chain)) { if (p == ep) { LIST_REMOVE(p, chain); lck_rw_unlock_exclusive(&encaptab_lock); kfree_type(struct encaptab, p); /*XXX*/ return 0; } } lck_rw_unlock_exclusive(&encaptab_lock); return EINVAL; } static int mask_match(const struct encaptab *ep, const struct sockaddr *sp, const struct sockaddr *dp) { struct sockaddr_storage s; struct sockaddr_storage d; int i; const u_int8_t *p, *q; u_int8_t *r; int matchlen; if (sp->sa_len > sizeof(s) || dp->sa_len > sizeof(d)) { return 0; } if (sp->sa_family != ep->af || dp->sa_family != ep->af) { return 0; } if (sp->sa_len != ep->src.ss_len || dp->sa_len != ep->dst.ss_len) { return 0; } matchlen = 0; p = (const u_int8_t *)sp; q = (const u_int8_t *)&ep->srcmask; r = (u_int8_t *)&s; for (i = 0; i < sp->sa_len; i++) { r[i] = p[i] & q[i]; /* XXX estimate */ matchlen += (q[i] ? 8 : 0); } p = (const u_int8_t *)dp; q = (const u_int8_t *)&ep->dstmask; r = (u_int8_t *)&d; for (i = 0; i < dp->sa_len; i++) { r[i] = p[i] & q[i]; /* XXX rough estimate */ matchlen += (q[i] ? 8 : 0); } /* need to overwrite len/family portion as we don't compare them */ s.ss_len = sp->sa_len; s.ss_family = sp->sa_family; d.ss_len = dp->sa_len; d.ss_family = dp->sa_family; if (bcmp(&s, &ep->src, ep->src.ss_len) == 0 && bcmp(&d, &ep->dst, ep->dst.ss_len) == 0) { return matchlen; } else { return 0; } } struct encaptabtag { void* *arg; }; static void encap_fillarg( struct mbuf *m, void *arg) { struct m_tag *tag; struct encaptabtag *et; tag = m_tag_create(KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_ENCAP, sizeof(struct encaptabtag), M_WAITOK, m); if (tag != NULL) { et = (struct encaptabtag*)(tag->m_tag_data); et->arg = arg; m_tag_prepend(m, tag); } } void * encap_getarg(struct mbuf *m) { struct m_tag *tag; struct encaptabtag *et; void *p = NULL; tag = m_tag_locate(m, KERNEL_MODULE_TAG_ID, KERNEL_TAG_TYPE_ENCAP); if (tag) { et = (struct encaptabtag*)(tag->m_tag_data); p = et->arg; m_tag_delete(m, tag); } return p; } struct encaptab_tag_container { struct m_tag encaptab_m_tag; struct encaptabtag encaptab_tag; }; static struct m_tag * m_tag_kalloc_encap(u_int32_t id, u_int16_t type, uint16_t len, int wait) { struct encaptab_tag_container *tag_container; struct m_tag *tag = NULL; assert3u(id, ==, KERNEL_MODULE_TAG_ID); assert3u(type, ==, KERNEL_TAG_TYPE_ENCAP); assert3u(len, ==, sizeof(struct encaptabtag)); if (len != sizeof(struct encaptabtag)) { return NULL; } tag_container = kalloc_type(struct encaptab_tag_container, wait | M_ZERO); if (tag_container != NULL) { tag = &tag_container->encaptab_m_tag; assert3p(tag, ==, tag_container); M_TAG_INIT(tag, id, type, len, &tag_container->encaptab_tag, NULL); } return tag; } static void m_tag_kfree_encap(struct m_tag *tag) { struct encaptab_tag_container *tag_container = (struct encaptab_tag_container *)tag; assert3u(tag->m_tag_len, ==, sizeof(struct encaptabtag)); kfree_type(struct encaptab_tag_container, tag_container); } void encap_register_m_tag(void) { int error; error = m_register_internal_tag_type(KERNEL_TAG_TYPE_ENCAP, sizeof(struct encaptabtag), m_tag_kalloc_encap, m_tag_kfree_encap); assert3u(error, ==, 0); }