NetBSD/sys/netinet/ip_encap.c
pooka 0f2034ae5e Make it possible to register delayed radix tree head inits which
will be processed when the radix "subsystem" is initialized -- all
users must be attached before any inits to know the max keylength.
Use of link sets is no longer required, and only attached domains
need to be considered.
2009-05-27 17:46:49 +00:00

883 lines
20 KiB
C

/* $KAME: ip_encap.c,v 1.73 2001/10/02 08:30:58 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
* RFC3056 6to4 tunnel
* isatap tunnel
* mobile-ip6 (uses RFC2473)
* 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? */
/*
* With USE_RADIX the code will use radix table for tunnel lookup, for
* tunnels registered with encap_attach() with a addr/mask pair.
* Faster on machines with thousands of tunnel registerations (= interfaces).
*
* The code assumes that radix table code can handle non-continuous netmask,
* as it will pass radix table memory region with (src + dst) sockaddr pair.
*
* FreeBSD is excluded here as they make max_keylen a static variable, and
* thus forbid definition of radix table other than proper domains.
*
* !!!!!!!
* !!NOTE: dom_maxrtkey assumes USE_RADIX is defined.
* !!!!!!!
*/
#define USE_RADIX
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ip_encap.c,v 1.38 2009/05/27 17:46:49 pooka Exp $");
#include "opt_mrouting.h"
#include "opt_inet.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 MROUTING
#include <netinet/ip_mroute.h>
#endif /* MROUTING */
#ifdef INET6
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet6/ip6protosw.h>
#include <netinet6/in6_var.h>
#include <netinet6/in6_pcb.h>
#include <netinet/icmp6.h>
#endif
#include <machine/stdarg.h>
#include <net/net_osdep.h>
enum direction { INBOUND, OUTBOUND };
#ifdef INET
static struct encaptab *encap4_lookup(struct mbuf *, int, int, enum direction);
#endif
#ifdef INET6
static struct encaptab *encap6_lookup(struct mbuf *, int, int, enum direction);
#endif
static int encap_add(struct encaptab *);
static int encap_remove(struct encaptab *);
static int encap_afcheck(int, const struct sockaddr *, const struct sockaddr *);
#ifdef USE_RADIX
static struct radix_node_head *encap_rnh(int);
static int mask_matchlen(const struct sockaddr *);
#endif
#ifndef USE_RADIX
static int mask_match(const struct encaptab *, const struct sockaddr *,
const struct sockaddr *);
#endif
static void encap_fillarg(struct mbuf *, const struct encaptab *);
LIST_HEAD(, encaptab) encaptab = LIST_HEAD_INITIALIZER(&encaptab);
#ifdef USE_RADIX
extern int max_keylen; /* radix.c */
struct radix_node_head *encap_head[2]; /* 0 for AF_INET, 1 for AF_INET6 */
#endif
void
encap_init(void)
{
static int initialized = 0;
if (initialized)
return;
initialized++;
#if 0
/*
* we cannot use LIST_INIT() here, since drivers may want to call
* encap_attach(), on driver attach. encap_init() will be called
* on AF_INET{,6} initialization, which happens after driver
* initialization - using LIST_INIT() here can nuke encap_attach()
* from drivers.
*/
LIST_INIT(&encaptab);
#endif
#ifdef USE_RADIX
/*
* initialize radix lookup table when the radix subsystem is inited.
*/
rn_delayedinit((void *)&encap_head[0],
sizeof(struct sockaddr_pack) << 3);
#ifdef INET6
rn_delayedinit((void *)&encap_head[1],
sizeof(struct sockaddr_pack) << 3);
#endif
#endif
}
#ifdef INET
static struct encaptab *
encap4_lookup(struct mbuf *m, int off, int proto, enum direction dir)
{
struct ip *ip;
struct ip_pack4 pack;
struct encaptab *ep, *match;
int prio, matchprio;
#ifdef USE_RADIX
struct radix_node_head *rnh = encap_rnh(AF_INET);
struct radix_node *rn;
#endif
#ifdef DIAGNOSTIC
if (m->m_len < sizeof(*ip))
panic("encap4_lookup");
#endif
ip = mtod(m, struct ip *);
memset(&pack, 0, sizeof(pack));
pack.p.sp_len = sizeof(pack);
pack.mine.sin_family = pack.yours.sin_family = AF_INET;
pack.mine.sin_len = pack.yours.sin_len = sizeof(struct sockaddr_in);
if (dir == INBOUND) {
pack.mine.sin_addr = ip->ip_dst;
pack.yours.sin_addr = ip->ip_src;
} else {
pack.mine.sin_addr = ip->ip_src;
pack.yours.sin_addr = ip->ip_dst;
}
match = NULL;
matchprio = 0;
#ifdef USE_RADIX
rn = rnh->rnh_matchaddr((void *)&pack, rnh);
if (rn && (rn->rn_flags & RNF_ROOT) == 0) {
match = (struct encaptab *)rn;
matchprio = mask_matchlen(match->srcmask) +
mask_matchlen(match->dstmask);
}
#endif
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 {
#ifdef USE_RADIX
continue;
#else
prio = mask_match(ep, (struct sockaddr *)&pack.mine,
(struct sockaddr *)&pack.yours);
#endif
}
/*
* 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).
*
* For radix-based lookup, I guess source takes precedence.
* See rn_{refines,lexobetter} for the correct answer.
*/
if (prio <= 0)
continue;
if (prio > matchprio) {
matchprio = prio;
match = ep;
}
}
return match;
#undef s
#undef d
}
void
encap4_input(struct mbuf *m, ...)
{
int off, proto;
va_list ap;
const struct protosw *psw;
struct encaptab *match;
va_start(ap, m);
off = va_arg(ap, int);
proto = va_arg(ap, int);
va_end(ap);
match = encap4_lookup(m, off, proto, INBOUND);
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, proto);
} else
m_freem(m);
return;
}
/* last resort: inject to raw socket */
rip_input(m, off, proto);
}
#endif
#ifdef INET6
static struct encaptab *
encap6_lookup(struct mbuf *m, int off, int proto, enum direction dir)
{
struct ip6_hdr *ip6;
struct ip_pack6 pack;
int prio, matchprio;
struct encaptab *ep, *match;
#ifdef USE_RADIX
struct radix_node_head *rnh = encap_rnh(AF_INET6);
struct radix_node *rn;
#endif
#ifdef DIAGNOSTIC
if (m->m_len < sizeof(*ip6))
panic("encap6_lookup");
#endif
ip6 = mtod(m, struct ip6_hdr *);
memset(&pack, 0, sizeof(pack));
pack.p.sp_len = sizeof(pack);
pack.mine.sin6_family = pack.yours.sin6_family = AF_INET6;
pack.mine.sin6_len = pack.yours.sin6_len = sizeof(struct sockaddr_in6);
if (dir == INBOUND) {
pack.mine.sin6_addr = ip6->ip6_dst;
pack.yours.sin6_addr = ip6->ip6_src;
} else {
pack.mine.sin6_addr = ip6->ip6_src;
pack.yours.sin6_addr = ip6->ip6_dst;
}
match = NULL;
matchprio = 0;
#ifdef USE_RADIX
rn = rnh->rnh_matchaddr((void *)&pack, rnh);
if (rn && (rn->rn_flags & RNF_ROOT) == 0) {
match = (struct encaptab *)rn;
matchprio = mask_matchlen(match->srcmask) +
mask_matchlen(match->dstmask);
}
#endif
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, off, proto, ep->arg);
else {
#ifdef USE_RADIX
continue;
#else
prio = mask_match(ep, (struct sockaddr *)&pack.mine,
(struct sockaddr *)&pack.yours);
#endif
}
/* see encap4_lookup() for issues here */
if (prio <= 0)
continue;
if (prio > matchprio) {
matchprio = prio;
match = ep;
}
}
return match;
#undef s
#undef d
}
int
encap6_input(struct mbuf **mp, int *offp, int proto)
{
struct mbuf *m = *mp;
const struct ip6protosw *psw;
struct encaptab *match;
match = encap6_lookup(m, *offp, proto, INBOUND);
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
static int
encap_add(struct encaptab *ep)
{
#ifdef USE_RADIX
struct radix_node_head *rnh = encap_rnh(ep->af);
#endif
int error = 0;
LIST_INSERT_HEAD(&encaptab, ep, chain);
#ifdef USE_RADIX
if (!ep->func && rnh) {
if (!rnh->rnh_addaddr((void *)ep->addrpack,
(void *)ep->maskpack, rnh, ep->nodes)) {
error = EEXIST;
goto fail;
}
}
#endif
return error;
fail:
LIST_REMOVE(ep, chain);
return error;
}
static int
encap_remove(struct encaptab *ep)
{
#ifdef USE_RADIX
struct radix_node_head *rnh = encap_rnh(ep->af);
#endif
int error = 0;
LIST_REMOVE(ep, chain);
#ifdef USE_RADIX
if (!ep->func && rnh) {
if (!rnh->rnh_deladdr((void *)ep->addrpack,
(void *)ep->maskpack, rnh))
error = ESRCH;
}
#endif
return error;
}
static int
encap_afcheck(int af, const struct sockaddr *sp, const struct sockaddr *dp)
{
if (sp && dp) {
if (sp->sa_len != dp->sa_len)
return EINVAL;
if (af != sp->sa_family || af != dp->sa_family)
return EINVAL;
} else if (!sp && !dp)
;
else
return EINVAL;
switch (af) {
case AF_INET:
if (sp && sp->sa_len != sizeof(struct sockaddr_in))
return EINVAL;
if (dp && dp->sa_len != sizeof(struct sockaddr_in))
return EINVAL;
break;
#ifdef INET6
case AF_INET6:
if (sp && sp->sa_len != sizeof(struct sockaddr_in6))
return EINVAL;
if (dp && dp->sa_len != sizeof(struct sockaddr_in6))
return EINVAL;
break;
#endif
default:
return EAFNOSUPPORT;
}
return 0;
}
/*
* 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;
int error;
int s;
size_t l;
struct ip_pack4 *pack4;
#ifdef INET6
struct ip_pack6 *pack6;
#endif
s = splsoftnet();
/* sanity check on args */
error = encap_afcheck(af, sp, dp);
if (error)
goto fail;
/* check if anyone have already attached with exactly same config */
LIST_FOREACH(ep, &encaptab, chain) {
if (ep->af != af)
continue;
if (ep->proto != proto)
continue;
if (ep->func)
continue;
#ifdef DIAGNOSTIC
if (!ep->src || !ep->dst || !ep->srcmask || !ep->dstmask)
panic("null pointers in encaptab");
#endif
if (ep->src->sa_len != sp->sa_len ||
memcmp(ep->src, sp, sp->sa_len) != 0 ||
memcmp(ep->srcmask, sm, sp->sa_len) != 0)
continue;
if (ep->dst->sa_len != dp->sa_len ||
memcmp(ep->dst, dp, dp->sa_len) != 0 ||
memcmp(ep->dstmask, dm, dp->sa_len) != 0)
continue;
error = EEXIST;
goto fail;
}
switch (af) {
case AF_INET:
l = sizeof(*pack4);
break;
#ifdef INET6
case AF_INET6:
l = sizeof(*pack6);
break;
#endif
default:
goto fail;
}
/* M_NETADDR ok? */
ep = malloc(sizeof(*ep), M_NETADDR, M_NOWAIT|M_ZERO);
if (ep == NULL) {
error = ENOBUFS;
goto fail;
}
ep->addrpack = malloc(l, M_NETADDR, M_NOWAIT|M_ZERO);
if (ep->addrpack == NULL) {
error = ENOBUFS;
goto gc;
}
ep->maskpack = malloc(l, M_NETADDR, M_NOWAIT|M_ZERO);
if (ep->maskpack == NULL) {
error = ENOBUFS;
goto gc;
}
ep->af = af;
ep->proto = proto;
ep->addrpack->sa_len = l & 0xff;
ep->maskpack->sa_len = l & 0xff;
switch (af) {
case AF_INET:
pack4 = (struct ip_pack4 *)ep->addrpack;
ep->src = (struct sockaddr *)&pack4->mine;
ep->dst = (struct sockaddr *)&pack4->yours;
pack4 = (struct ip_pack4 *)ep->maskpack;
ep->srcmask = (struct sockaddr *)&pack4->mine;
ep->dstmask = (struct sockaddr *)&pack4->yours;
break;
#ifdef INET6
case AF_INET6:
pack6 = (struct ip_pack6 *)ep->addrpack;
ep->src = (struct sockaddr *)&pack6->mine;
ep->dst = (struct sockaddr *)&pack6->yours;
pack6 = (struct ip_pack6 *)ep->maskpack;
ep->srcmask = (struct sockaddr *)&pack6->mine;
ep->dstmask = (struct sockaddr *)&pack6->yours;
break;
#endif
}
memcpy(ep->src, sp, sp->sa_len);
memcpy(ep->srcmask, sm, sp->sa_len);
memcpy(ep->dst, dp, dp->sa_len);
memcpy(ep->dstmask, dm, dp->sa_len);
ep->psw = psw;
ep->arg = arg;
error = encap_add(ep);
if (error)
goto gc;
error = 0;
splx(s);
return ep;
gc:
if (ep->addrpack)
free(ep->addrpack, M_NETADDR);
if (ep->maskpack)
free(ep->maskpack, M_NETADDR);
if (ep)
free(ep, M_NETADDR);
fail:
splx(s);
return NULL;
}
const struct encaptab *
encap_attach_func(int af, int proto,
int (*func)(struct mbuf *, int, int, void *),
const struct protosw *psw, void *arg)
{
struct encaptab *ep;
int error;
int s;
s = splsoftnet();
/* sanity check on args */
if (!func) {
error = EINVAL;
goto fail;
}
error = encap_afcheck(af, NULL, NULL);
if (error)
goto fail;
ep = malloc(sizeof(*ep), M_NETADDR, M_NOWAIT); /*XXX*/
if (ep == NULL) {
error = ENOBUFS;
goto fail;
}
memset(ep, 0, sizeof(*ep));
ep->af = af;
ep->proto = proto;
ep->func = func;
ep->psw = psw;
ep->arg = arg;
error = encap_add(ep);
if (error)
goto fail;
error = 0;
splx(s);
return ep;
fail:
splx(s);
return NULL;
}
/* XXX encap4_ctlinput() is necessary if we set DF=1 on outer IPv4 header */
#ifdef INET6
void *
encap6_ctlinput(int cmd, const struct sockaddr *sa, void *d0)
{
void *d = d0;
struct ip6_hdr *ip6;
struct mbuf *m;
int off;
struct ip6ctlparam *ip6cp = NULL;
int nxt;
struct encaptab *ep;
const struct ip6protosw *psw;
if (sa->sa_family != AF_INET6 ||
sa->sa_len != sizeof(struct sockaddr_in6))
return NULL;
if ((unsigned)cmd >= PRC_NCMDS)
return NULL;
if (cmd == PRC_HOSTDEAD)
d = NULL;
else if (cmd == PRC_MSGSIZE)
; /* special code is present, see below */
else if (inet6ctlerrmap[cmd] == 0)
return NULL;
/* if the parameter is from icmp6, decode it. */
if (d != NULL) {
ip6cp = (struct ip6ctlparam *)d;
m = ip6cp->ip6c_m;
ip6 = ip6cp->ip6c_ip6;
off = ip6cp->ip6c_off;
nxt = ip6cp->ip6c_nxt;
if (ip6 && cmd == PRC_MSGSIZE) {
int valid = 0;
struct encaptab *match;
/*
* Check to see if we have a valid encap configuration.
*/
match = encap6_lookup(m, off, nxt, OUTBOUND);
if (match)
valid++;
/*
* Depending on the value of "valid" and routing table
* size (mtudisc_{hi,lo}wat), we will:
* - recalcurate the new MTU and create the
* corresponding routing entry, or
* - ignore the MTU change notification.
*/
icmp6_mtudisc_update((struct ip6ctlparam *)d, valid);
}
} else {
m = NULL;
ip6 = NULL;
nxt = -1;
}
/* inform all listeners */
LIST_FOREACH(ep, &encaptab, chain) {
if (ep->af != AF_INET6)
continue;
if (ep->proto >= 0 && ep->proto != nxt)
continue;
/* should optimize by looking at address pairs */
/* XXX need to pass ep->arg or ep itself to listeners */
psw = (const struct ip6protosw *)ep->psw;
if (psw && psw->pr_ctlinput)
(*psw->pr_ctlinput)(cmd, sa, d);
}
rip6_ctlinput(cmd, sa, d0);
return NULL;
}
#endif
int
encap_detach(const struct encaptab *cookie)
{
const struct encaptab *ep = cookie;
struct encaptab *p;
int error;
LIST_FOREACH(p, &encaptab, chain) {
if (p == ep) {
error = encap_remove(p);
if (error)
return error;
if (!ep->func) {
free(p->addrpack, M_NETADDR);
free(p->maskpack, M_NETADDR);
}
free(p, M_NETADDR); /*XXX*/
return 0;
}
}
return ENOENT;
}
#ifdef USE_RADIX
static struct radix_node_head *
encap_rnh(int af)
{
switch (af) {
case AF_INET:
return encap_head[0];
#ifdef INET6
case AF_INET6:
return encap_head[1];
#endif
default:
return NULL;
}
}
static int
mask_matchlen(const struct sockaddr *sa)
{
const char *p, *ep;
int l;
p = (const char *)sa;
ep = p + sa->sa_len;
p += 2; /* sa_len + sa_family */
l = 0;
while (p < ep) {
l += (*p ? 8 : 0); /* estimate */
p++;
}
return l;
}
#endif
#ifndef USE_RADIX
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;
#ifdef DIAGNOSTIC
if (ep->func)
panic("wrong encaptab passed to mask_match");
#endif
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->sa_len || dp->sa_len != ep->dst->sa_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 (memcmp(&s, ep->src, ep->src->sa_len) == 0 &&
memcmp(&d, ep->dst, ep->dst->sa_len) == 0) {
return matchlen;
} else
return 0;
}
#endif
static void
encap_fillarg(struct mbuf *m, const struct encaptab *ep)
{
struct m_tag *mtag;
mtag = m_tag_get(PACKET_TAG_ENCAP, sizeof(void *), M_NOWAIT);
if (mtag) {
*(void **)(mtag + 1) = ep->arg;
m_tag_prepend(m, mtag);
}
}
void *
encap_getarg(struct mbuf *m)
{
void *p;
struct m_tag *mtag;
p = NULL;
mtag = m_tag_find(m, PACKET_TAG_ENCAP, NULL);
if (mtag != NULL) {
p = *(void **)(mtag + 1);
m_tag_delete(m, mtag);
}
return p;
}