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/* $OpenBSD: mpls_output.c,v 1.29 2023/05/13 13:35:18 bluhm Exp $ */
/*
* Copyright (c) 2008 Claudio Jeker <claudio@openbsd.org>
* Copyright (c) 2008 Michele Marchetto <michele@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/param.h>
#include <sys/mbuf.h>
#include <sys/systm.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/route.h>
#include <netmpls/mpls.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#ifdef INET6
#include <netinet/ip6.h>
#endif
#ifdef MPLS_DEBUG
#define MPLS_LABEL_GET(l) ((ntohl((l) & MPLS_LABEL_MASK)) >> MPLS_LABEL_OFFSET)
#endif
u_int8_t mpls_getttl(struct mbuf *, sa_family_t);
int
mpls_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
struct rtentry *rt)
{
struct sockaddr_mpls *smpls;
struct sockaddr_mpls sa_mpls;
struct shim_hdr *shim;
struct rt_mpls *rt_mpls;
int error;
u_int8_t ttl;
if (rt == NULL || (dst->sa_family != AF_INET &&
dst->sa_family != AF_INET6 && dst->sa_family != AF_MPLS)) {
if (!ISSET(ifp->if_xflags, IFXF_MPLS))
return (ifp->if_output(ifp, m, dst, rt));
else
return (ifp->if_ll_output(ifp, m, dst, rt));
}
/* need to calculate checksums now if necessary */
if (m->m_pkthdr.csum_flags & M_IPV4_CSUM_OUT)
in_hdr_cksum_out(m, NULL);
in_proto_cksum_out(m, NULL);
/* initialize sockaddr_mpls */
bzero(&sa_mpls, sizeof(sa_mpls));
smpls = &sa_mpls;
smpls->smpls_family = AF_MPLS;
smpls->smpls_len = sizeof(*smpls);
ttl = mpls_getttl(m, dst->sa_family);
rt_mpls = (struct rt_mpls *)rt->rt_llinfo;
if (rt_mpls == NULL || (rt->rt_flags & RTF_MPLS) == 0) {
/* no MPLS information for this entry */
if (!ISSET(ifp->if_xflags, IFXF_MPLS)) {
#ifdef MPLS_DEBUG
printf("MPLS_DEBUG: interface not mpls enabled\n");
#endif
error = ENETUNREACH;
goto bad;
}
return (ifp->if_ll_output(ifp, m, dst, rt));
}
/* to be honest here only the push operation makes sense */
switch (rt_mpls->mpls_operation) {
case MPLS_OP_PUSH:
m = mpls_shim_push(m, rt_mpls);
break;
case MPLS_OP_POP:
m = mpls_shim_pop(m);
break;
case MPLS_OP_SWAP:
m = mpls_shim_swap(m, rt_mpls);
break;
default:
error = EINVAL;
goto bad;
}
if (m == NULL) {
error = ENOBUFS;
goto bad;
}
/* refetch label */
shim = mtod(m, struct shim_hdr *);
/* mark first label with BOS flag */
if (dst->sa_family != AF_MPLS)
shim->shim_label |= MPLS_BOS_MASK;
/* write back TTL */
shim->shim_label &= ~MPLS_TTL_MASK;
shim->shim_label |= htonl(ttl);
#ifdef MPLS_DEBUG
printf("MPLS: sending on %s outshim %x outlabel %d\n",
ifp->if_xname, ntohl(shim->shim_label),
MPLS_LABEL_GET(rt_mpls->mpls_label));
#endif
/* Output iface is not MPLS-enabled */
if (!ISSET(ifp->if_xflags, IFXF_MPLS)) {
#ifdef MPLS_DEBUG
printf("MPLS_DEBUG: interface not mpls enabled\n");
#endif
error = ENETUNREACH;
goto bad;
}
/* reset broadcast and multicast flags, this is a P2P tunnel */
m->m_flags &= ~(M_BCAST | M_MCAST);
smpls->smpls_label = shim->shim_label & MPLS_LABEL_MASK;
error = ifp->if_ll_output(ifp, m, smplstosa(smpls), rt);
return (error);
bad:
m_freem(m);
return (error);
}
u_int8_t
mpls_getttl(struct mbuf *m, sa_family_t af)
{
struct mbuf *n;
int loc, off;
u_int8_t ttl = mpls_defttl;
/* If the AF is MPLS then inherit the TTL from the present label. */
if (af == AF_MPLS)
loc = 3;
else {
switch (*mtod(m, uint8_t *) >> 4) {
case 4:
if (!mpls_mapttl_ip)
return (ttl);
loc = offsetof(struct ip, ip_ttl);
break;
#ifdef INET6
case 6:
if (!mpls_mapttl_ip6)
return (ttl);
loc = offsetof(struct ip6_hdr, ip6_hlim);
break;
#endif
default:
return (ttl);
}
}
n = m_getptr(m, loc, &off);
if (n == NULL)
return (ttl);
ttl = *(mtod(n, uint8_t *) + off);
return (ttl);
}
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