/*
* Copyright (c) 2000-2024 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,
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*/
/* $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 <sys/param.h>
#include <sys/systm.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/mbuf.h>
#include <sys/mcache.h>
#include <sys/errno.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/queue.h>
#include <net/if.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/ip_encap.h>
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet6/ip6protosw.h>
#include <net/net_osdep.h>
#include <net/sockaddr_utils.h>
#ifndef __APPLE__
#include <sys/kernel.h>
#include <sys/malloc.h>
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 *__single ip;
struct sockaddr_in s, d;
const struct protosw *psw;
struct encaptab *__single ep, *__single match;
int prio, matchprio;
void *__single 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)
{
mbuf_ref_t m = *mp;
struct ip6_hdr *__single ip6;
struct sockaddr_in6 s, d;
const struct ip6protosw *__single psw;
struct encaptab *__single ep, *__single match;
int prio, matchprio;
void *__single 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 = SA_BYTES(sp);
q = SA_BYTES(&ep->srcmask);
r = SA_BYTES(&s);
for (i = 0; i < sp->sa_len; i++) {
r[i] = p[i] & q[i];
/* XXX estimate */
matchlen += (q[i] ? 8 : 0);
}
p = SA_BYTES(dp);
q = SA_BYTES(&ep->dstmask);
r = SA_BYTES(&s);
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 *__single tag;
struct encaptabtag *__single et;
void *__single 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 *__single 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);
}