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FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
| Current File : //sys/netinet/ip_encap.c |
/* $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)
* RFC3056 6to4 tunnel
* isatap 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/IPComp 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/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/sys/netinet/ip_encap.c 201145 2009-12-28 22:56:30Z antoine $");
#include "opt_mrouting.h"
#include "opt_inet.h"
#include "opt_inet6.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/mbuf.h>
#include <sys/errno.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>
#ifdef INET6
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet6/ip6protosw.h>
#endif
#include <machine/stdarg.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
static MALLOC_DEFINE(M_NETADDR, "encap_export_host", "Export host address structure");
static void encap_add(struct encaptab *);
static int mask_match(const struct encaptab *, const struct sockaddr *,
const struct sockaddr *);
static void encap_fillarg(struct mbuf *, const struct encaptab *);
/*
* All global variables in ip_encap.c are locked using encapmtx.
*/
static struct mtx encapmtx;
MTX_SYSINIT(encapmtx, &encapmtx, "encapmtx", MTX_DEF);
LIST_HEAD(, encaptab) encaptab = LIST_HEAD_INITIALIZER(encaptab);
/*
* We currently keey encap_init() for source code compatibility reasons --
* it's referenced by KAME pieces in netinet6.
*/
void
encap_init(void)
{
}
#ifdef INET
void
encap4_input(struct mbuf *m, int off)
{
struct ip *ip;
int proto;
struct sockaddr_in s, d;
const struct protosw *psw;
struct encaptab *ep, *match;
int prio, matchprio;
ip = mtod(m, struct ip *);
proto = ip->ip_p;
bzero(&s, sizeof(s));
s.sin_family = AF_INET;
s.sin_len = sizeof(struct sockaddr_in);
s.sin_addr = ip->ip_src;
bzero(&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;
mtx_lock(&encapmtx);
LIST_FOREACH(ep, &encaptab, 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, (struct sockaddr *)&d,
(struct sockaddr *)&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;
}
}
mtx_unlock(&encapmtx);
if (match) {
/* found a match, "match" has the best one */
psw = match->psw;
if (psw && psw->pr_input) {
encap_fillarg(m, match);
(*psw->pr_input)(m, off);
} else
m_freem(m);
return;
}
/* last resort: inject to raw socket */
rip_input(m, off);
}
#endif
#ifdef INET6
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;
ip6 = mtod(m, struct ip6_hdr *);
bzero(&s, sizeof(s));
s.sin6_family = AF_INET6;
s.sin6_len = sizeof(struct sockaddr_in6);
s.sin6_addr = ip6->ip6_src;
bzero(&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;
mtx_lock(&encapmtx);
LIST_FOREACH(ep, &encaptab, 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, (struct sockaddr *)&d,
(struct sockaddr *)&s);
}
/* see encap4_input() for issues here */
if (prio <= 0)
continue;
if (prio > matchprio) {
matchprio = prio;
match = ep;
}
}
mtx_unlock(&encapmtx);
if (match) {
/* found a match */
psw = (const struct ip6protosw *)match->psw;
if (psw && psw->pr_input) {
encap_fillarg(m, match);
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);
}
#endif
/*lint -sem(encap_add, custodial(1)) */
static void
encap_add(struct encaptab *ep)
{
mtx_assert(&encapmtx, MA_OWNED);
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;
/* sanity check on args */
if (sp->sa_len > sizeof(ep->src) || dp->sa_len > sizeof(ep->dst))
return (NULL);
if (sp->sa_len != dp->sa_len)
return (NULL);
if (af != sp->sa_family || af != dp->sa_family)
return (NULL);
/* check if anyone have already attached with exactly same config */
mtx_lock(&encapmtx);
LIST_FOREACH(ep, &encaptab, chain) {
if (ep->af != af)
continue;
if (ep->proto != proto)
continue;
if (ep->src.ss_len != sp->sa_len ||
bcmp(&ep->src, sp, sp->sa_len) != 0 ||
bcmp(&ep->srcmask, sm, sp->sa_len) != 0)
continue;
if (ep->dst.ss_len != dp->sa_len ||
bcmp(&ep->dst, dp, dp->sa_len) != 0 ||
bcmp(&ep->dstmask, dm, dp->sa_len) != 0)
continue;
mtx_unlock(&encapmtx);
return (NULL);
}
ep = malloc(sizeof(*ep), M_NETADDR, M_NOWAIT); /*XXX*/
if (ep == NULL) {
mtx_unlock(&encapmtx);
return (NULL);
}
bzero(ep, sizeof(*ep));
ep->af = af;
ep->proto = proto;
bcopy(sp, &ep->src, sp->sa_len);
bcopy(sm, &ep->srcmask, sp->sa_len);
bcopy(dp, &ep->dst, dp->sa_len);
bcopy(dm, &ep->dstmask, dp->sa_len);
ep->psw = psw;
ep->arg = arg;
encap_add(ep);
mtx_unlock(&encapmtx);
return (ep);
}
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;
/* sanity check on args */
if (!func)
return (NULL);
ep = malloc(sizeof(*ep), M_NETADDR, M_NOWAIT); /*XXX*/
if (ep == NULL)
return (NULL);
bzero(ep, sizeof(*ep));
ep->af = af;
ep->proto = proto;
ep->func = func;
ep->psw = psw;
ep->arg = arg;
mtx_lock(&encapmtx);
encap_add(ep);
mtx_unlock(&encapmtx);
return (ep);
}
int
encap_detach(const struct encaptab *cookie)
{
const struct encaptab *ep = cookie;
struct encaptab *p;
mtx_lock(&encapmtx);
LIST_FOREACH(p, &encaptab, chain) {
if (p == ep) {
LIST_REMOVE(p, chain);
mtx_unlock(&encapmtx);
free(p, M_NETADDR); /*XXX*/
return 0;
}
}
mtx_unlock(&encapmtx);
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;
}
static void
encap_fillarg(struct mbuf *m, const struct encaptab *ep)
{
struct m_tag *tag;
tag = m_tag_get(PACKET_TAG_ENCAP, sizeof (void*), M_NOWAIT);
if (tag) {
*(void**)(tag+1) = ep->arg;
m_tag_prepend(m, tag);
}
}
void *
encap_getarg(struct mbuf *m)
{
void *p = NULL;
struct m_tag *tag;
tag = m_tag_find(m, PACKET_TAG_ENCAP, NULL);
if (tag) {
p = *(void**)(tag+1);
m_tag_delete(m, tag);
}
return p;
}