NetBSD/sys/net/if_mpls.c

668 lines
15 KiB
C

/* $NetBSD: if_mpls.c,v 1.11 2013/10/25 09:25:32 kefren Exp $ */
/*
* Copyright (c) 2010 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Mihai Chelaru <kefren@NetBSD.org>
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: if_mpls.c,v 1.11 2013/10/25 09:25:32 kefren Exp $");
#include "opt_inet.h"
#include "opt_mpls.h"
#include <sys/param.h>
#include <sys/errno.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/sysctl.h>
#include <net/bpf.h>
#include <net/if.h>
#include <net/if_types.h>
#include <net/netisr.h>
#include <net/route.h>
#ifdef INET
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#endif
#ifdef INET6
#include <netinet/ip6.h>
#include <netinet6/in6_var.h>
#include <netinet6/ip6_var.h>
#endif
#include <netmpls/mpls.h>
#include <netmpls/mpls_var.h>
#include "if_mpls.h"
#define TRIM_LABEL do { \
m_adj(m, sizeof(union mpls_shim)); \
if (m->m_len < sizeof(union mpls_shim) && \
(m = m_pullup(m, sizeof(union mpls_shim))) == NULL) \
goto done; \
dst.smpls_addr.s_addr = ntohl(mtod(m, union mpls_shim *)->s_addr); \
} while (/* CONSTCOND */ 0)
void ifmplsattach(int);
static int mpls_clone_create(struct if_clone *, int);
static int mpls_clone_destroy(struct ifnet *);
static struct if_clone mpls_if_cloner =
IF_CLONE_INITIALIZER("mpls", mpls_clone_create, mpls_clone_destroy);
static void mpls_input(struct ifnet *, struct mbuf *);
static int mpls_output(struct ifnet *, struct mbuf *, const struct sockaddr *,
struct rtentry *);
static int mpls_ioctl(struct ifnet *, u_long, void *);
static int mpls_send_frame(struct mbuf *, struct ifnet *, struct rtentry *);
static int mpls_lse(struct mbuf *);
#ifdef INET
static int mpls_unlabel_inet(struct mbuf *);
static struct mbuf *mpls_label_inet(struct mbuf *, union mpls_shim *, uint);
#endif
#ifdef INET6
static int mpls_unlabel_inet6(struct mbuf *);
static struct mbuf *mpls_label_inet6(struct mbuf *, union mpls_shim *, uint);
#endif
static struct mbuf *mpls_prepend_shim(struct mbuf *, union mpls_shim *);
extern int mpls_defttl, mpls_mapttl_inet, mpls_mapttl_inet6, mpls_icmp_respond,
mpls_forwarding, mpls_accept, mpls_mapprec_inet, mpls_mapclass_inet6,
mpls_rfc4182;
/* ARGSUSED */
void
ifmplsattach(int count)
{
if_clone_attach(&mpls_if_cloner);
}
static int
mpls_clone_create(struct if_clone *ifc, int unit)
{
struct mpls_softc *sc;
sc = malloc(sizeof(*sc), M_DEVBUF, M_WAITOK | M_ZERO);
if_initname(&sc->sc_if, ifc->ifc_name, unit);
sc->sc_if.if_softc = sc;
sc->sc_if.if_type = IFT_MPLS;
sc->sc_if.if_addrlen = 0;
sc->sc_if.if_hdrlen = sizeof(union mpls_shim);
sc->sc_if.if_dlt = DLT_NULL;
sc->sc_if.if_mtu = 1500;
sc->sc_if.if_flags = 0;
sc->sc_if.if_input = mpls_input;
sc->sc_if.if_output = mpls_output;
sc->sc_if.if_ioctl = mpls_ioctl;
if_attach(&sc->sc_if);
if_alloc_sadl(&sc->sc_if);
bpf_attach(&sc->sc_if, DLT_NULL, sizeof(uint32_t));
return 0;
}
static int
mpls_clone_destroy(struct ifnet *ifp)
{
int s;
bpf_detach(ifp);
s = splnet();
if_detach(ifp);
splx(s);
free(ifp->if_softc, M_DEVBUF);
return 0;
}
static void
mpls_input(struct ifnet *ifp, struct mbuf *m)
{
#if 0
/*
* TODO - kefren
* I'd love to unshim the packet, guess family
* and pass it to bpf
*/
bpf_mtap_af(ifp, AF_MPLS, m);
#endif
mpls_lse(m);
}
void
mplsintr(void)
{
struct mbuf *m;
int s;
while (!IF_IS_EMPTY(&mplsintrq)) {
s = splnet();
IF_DEQUEUE(&mplsintrq, m);
splx(s);
if (!m)
return;
if (((m->m_flags & M_PKTHDR) == 0) ||
(m->m_pkthdr.rcvif == 0))
panic("mplsintr(): no pkthdr or rcvif");
#ifdef MBUFTRACE
m_claimm(m, &mpls_owner);
#endif
mpls_input(m->m_pkthdr.rcvif, m);
}
}
/*
* prepend shim and deliver
*/
static int
mpls_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst, struct rtentry *rt)
{
union mpls_shim mh, *pms;
struct rtentry *rt1;
int err;
uint psize = sizeof(struct sockaddr_mpls);
if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) {
m_freem(m);
return ENETDOWN;
}
if (rt_gettag(rt) == NULL || rt_gettag(rt)->sa_family != AF_MPLS) {
m_freem(m);
return EINVAL;
}
bpf_mtap_af(ifp, dst->sa_family, m);
memset(&mh, 0, sizeof(mh));
mh.s_addr = MPLS_GETSADDR(rt);
mh.shim.bos = 1;
mh.shim.exp = 0;
mh.shim.ttl = mpls_defttl;
pms = &((struct sockaddr_mpls*)rt_gettag(rt))->smpls_addr;
while (psize <= rt_gettag(rt)->sa_len - sizeof(mh)) {
pms++;
if (mh.shim.label != MPLS_LABEL_IMPLNULL &&
((m = mpls_prepend_shim(m, &mh)) == NULL))
return ENOBUFS;
memset(&mh, 0, sizeof(mh));
mh.s_addr = ntohl(pms->s_addr);
mh.shim.bos = mh.shim.exp = 0;
mh.shim.ttl = mpls_defttl;
psize += sizeof(mh);
}
switch(dst->sa_family) {
#ifdef INET
case AF_INET:
m = mpls_label_inet(m, &mh, psize - sizeof(struct sockaddr_mpls));
break;
#endif
#ifdef INET6
case AF_INET6:
m = mpls_label_inet6(m, &mh, psize - sizeof(struct sockaddr_mpls));
break;
#endif
default:
m = mpls_prepend_shim(m, &mh);
break;
}
if (m == NULL) {
IF_DROP(&ifp->if_snd);
ifp->if_oerrors++;
return ENOBUFS;
}
ifp->if_opackets++;
ifp->if_obytes += m->m_pkthdr.len;
if ((rt1=rtalloc1(rt->rt_gateway, 1)) == NULL) {
m_freem(m);
return EHOSTUNREACH;
}
err = mpls_send_frame(m, rt1->rt_ifp, rt);
RTFREE(rt1);
return err;
}
static int
mpls_ioctl(struct ifnet *ifp, u_long cmd, void *data)
{
int error = 0, s = splnet();
struct ifreq *ifr = data;
switch(cmd) {
case SIOCINITIFADDR:
ifp->if_flags |= IFF_UP | IFF_RUNNING;
break;
case SIOCSIFMTU:
if (ifr != NULL && ifr->ifr_mtu < 576) {
error = EINVAL;
break;
}
/* FALLTHROUGH */
case SIOCGIFMTU:
if ((error = ifioctl_common(ifp, cmd, data)) == ENETRESET)
error = 0;
break;
case SIOCSIFFLAGS:
if ((error = ifioctl_common(ifp, cmd, data)) != 0)
break;
if (ifp->if_flags & IFF_UP)
ifp->if_flags |= IFF_RUNNING;
break;
default:
error = ifioctl_common(ifp, cmd, data);
break;
}
splx(s);
return error;
}
/*
* MPLS Label Switch Engine
*/
static int
mpls_lse(struct mbuf *m)
{
struct sockaddr_mpls dst;
union mpls_shim tshim, *htag;
struct rtentry *rt = NULL;
int error = ENOBUFS;
uint psize = sizeof(struct sockaddr_mpls);
bool push_back_alert = false;
if (m->m_len < sizeof(union mpls_shim) &&
(m = m_pullup(m, sizeof(union mpls_shim))) == NULL)
goto done;
dst.smpls_len = sizeof(struct sockaddr_mpls);
dst.smpls_family = AF_MPLS;
dst.smpls_addr.s_addr = ntohl(mtod(m, union mpls_shim *)->s_addr);
/* Check if we're accepting MPLS Frames */
error = EINVAL;
if (!mpls_accept)
goto done;
/* TTL decrement */
if ((m = mpls_ttl_dec(m)) == NULL)
goto done;
/* RFC 4182 */
if (mpls_rfc4182 != 0)
while((dst.smpls_addr.shim.label == MPLS_LABEL_IPV4NULL ||
dst.smpls_addr.shim.label == MPLS_LABEL_IPV6NULL) &&
__predict_false(dst.smpls_addr.shim.bos == 0))
TRIM_LABEL;
/* RFC 3032 Section 2.1 Page 4 */
if (__predict_false(dst.smpls_addr.shim.label == MPLS_LABEL_RTALERT) &&
dst.smpls_addr.shim.bos == 0) {
TRIM_LABEL;
push_back_alert = true;
}
if (dst.smpls_addr.shim.label <= MPLS_LABEL_RESMAX) {
/* Don't swap reserved labels */
switch (dst.smpls_addr.shim.label) {
#ifdef INET
case MPLS_LABEL_IPV4NULL:
/* Pop shim and push mbuf to IP stack */
if (dst.smpls_addr.shim.bos)
error = mpls_unlabel_inet(m);
break;
#endif
#ifdef INET6
case MPLS_LABEL_IPV6NULL:
/* Pop shim and push mbuf to IPv6 stack */
if (dst.smpls_addr.shim.bos)
error = mpls_unlabel_inet6(m);
break;
#endif
case MPLS_LABEL_RTALERT: /* Yeah, I'm all alerted */
case MPLS_LABEL_IMPLNULL: /* This is logical only */
default: /* Rest are not allowed */
break;
}
goto done;
}
/* Check if we should do MPLS forwarding */
error = EHOSTUNREACH;
if (!mpls_forwarding)
goto done;
/* Get a route to dst */
dst.smpls_addr.shim.ttl =
dst.smpls_addr.shim.bos =
dst.smpls_addr.shim.exp = 0;
dst.smpls_addr.s_addr = htonl(dst.smpls_addr.s_addr);
if ((rt = rtalloc1((const struct sockaddr*)&dst, 1)) == NULL)
goto done;
/* MPLS packet with no MPLS tagged route ? */
if ((rt->rt_flags & RTF_GATEWAY) == 0 ||
rt_gettag(rt) == NULL ||
rt_gettag(rt)->sa_family != AF_MPLS)
goto done;
tshim.s_addr = MPLS_GETSADDR(rt);
/* Swap labels */
if ((m->m_len < sizeof(union mpls_shim)) &&
(m = m_pullup(m, sizeof(union mpls_shim))) == 0) {
error = ENOBUFS;
goto done;
}
/* Replace only the label */
htag = mtod(m, union mpls_shim *);
htag->s_addr = ntohl(htag->s_addr);
htag->shim.label = tshim.shim.label;
htag->s_addr = htonl(htag->s_addr);
/* check if there is anything more to prepend */
htag = &((struct sockaddr_mpls*)rt_gettag(rt))->smpls_addr;
while (psize <= rt_gettag(rt)->sa_len - sizeof(tshim)) {
htag++;
memset(&tshim, 0, sizeof(tshim));
tshim.s_addr = ntohl(htag->s_addr);
tshim.shim.bos = tshim.shim.exp = 0;
tshim.shim.ttl = mpls_defttl;
if (tshim.shim.label != MPLS_LABEL_IMPLNULL &&
((m = mpls_prepend_shim(m, &tshim)) == NULL))
return ENOBUFS;
psize += sizeof(tshim);
}
if (__predict_false(push_back_alert == true)) {
/* re-add the router alert label */
memset(&tshim, 0, sizeof(tshim));
tshim.s_addr = MPLS_LABEL_RTALERT;
tshim.shim.bos = tshim.shim.exp = 0;
tshim.shim.ttl = mpls_defttl;
if ((m = mpls_prepend_shim(m, &tshim)) == NULL)
return ENOBUFS;
}
error = mpls_send_frame(m, rt->rt_ifp, rt);
done:
if (error != 0 && m != NULL)
m_freem(m);
if (rt != NULL)
RTFREE(rt);
return error;
}
static int
mpls_send_frame(struct mbuf *m, struct ifnet *ifp, struct rtentry *rt)
{
union mpls_shim msh;
if ((rt->rt_flags & RTF_GATEWAY) == 0)
return EHOSTUNREACH;
rt->rt_use++;
msh.s_addr = MPLS_GETSADDR(rt);
if (msh.shim.label == MPLS_LABEL_IMPLNULL ||
(m->m_flags & (M_MCAST | M_BCAST))) {
m_adj(m, sizeof(union mpls_shim));
m->m_pkthdr.csum_flags = 0;
}
switch(ifp->if_type) {
/* only these are supported for now */
case IFT_ETHER:
case IFT_TUNNEL:
case IFT_LOOP:
return (*ifp->if_output)(ifp, m, rt->rt_gateway, rt);
break;
default:
return ENETUNREACH;
}
return 0;
}
#ifdef INET
static int
mpls_unlabel_inet(struct mbuf *m)
{
int s, iphlen;
struct ip *iph;
union mpls_shim *ms;
struct ifqueue *inq;
if (mpls_mapttl_inet || mpls_mapprec_inet) {
/* get shim info */
ms = mtod(m, union mpls_shim *);
ms->s_addr = ntohl(ms->s_addr);
/* and get rid of it */
m_adj(m, sizeof(union mpls_shim));
/* get ip header */
if (m->m_len < sizeof (struct ip) &&
(m = m_pullup(m, sizeof(struct ip))) == NULL)
return ENOBUFS;
iph = mtod(m, struct ip *);
iphlen = iph->ip_hl << 2;
/* get it all */
if (m->m_len < iphlen) {
if ((m = m_pullup(m, iphlen)) == NULL)
return ENOBUFS;
iph = mtod(m, struct ip *);
}
/* check ipsum */
if (in_cksum(m, iphlen) != 0) {
m_freem(m);
return EINVAL;
}
/* set IP ttl from MPLS ttl */
if (mpls_mapttl_inet)
iph->ip_ttl = ms->shim.ttl;
/* set IP Precedence from MPLS Exp */
if (mpls_mapprec_inet) {
iph->ip_tos = (iph->ip_tos << 3) >> 3;
iph->ip_tos |= ms->shim.exp << 5;
}
/* reset ipsum because we modified TTL and TOS */
iph->ip_sum = 0;
iph->ip_sum = in_cksum(m, iphlen);
} else
m_adj(m, sizeof(union mpls_shim));
/* Put it on IP queue */
inq = &ipintrq;
s = splnet();
if (IF_QFULL(inq)) {
IF_DROP(inq);
splx(s);
m_freem(m);
return ENOBUFS;
}
IF_ENQUEUE(inq, m);
splx(s);
schednetisr(NETISR_IP);
return 0;
}
/*
* Prepend MPLS label
*/
static struct mbuf *
mpls_label_inet(struct mbuf *m, union mpls_shim *ms, uint offset)
{
struct ip iphdr;
if (mpls_mapttl_inet || mpls_mapprec_inet) {
if ((m->m_len < sizeof(struct ip)) &&
(m = m_pullup(m, offset + sizeof(struct ip))) == 0)
return NULL; /* XXX */
m_copydata(m, offset, sizeof(struct ip), &iphdr);
/* Map TTL */
if (mpls_mapttl_inet)
ms->shim.ttl = iphdr.ip_ttl;
/* Copy IP precedence to EXP */
if (mpls_mapprec_inet)
ms->shim.exp = ((u_int8_t)iphdr.ip_tos) >> 5;
}
if ((m = mpls_prepend_shim(m, ms)) == NULL)
return NULL;
return m;
}
#endif /* INET */
#ifdef INET6
static int
mpls_unlabel_inet6(struct mbuf *m)
{
struct ip6_hdr *ip6hdr;
union mpls_shim ms;
struct ifqueue *inq;
int s;
/* TODO: mapclass */
if (mpls_mapttl_inet6) {
ms.s_addr = ntohl(mtod(m, union mpls_shim *)->s_addr);
m_adj(m, sizeof(union mpls_shim));
if (m->m_len < sizeof (struct ip6_hdr) &&
(m = m_pullup(m, sizeof(struct ip6_hdr))) == 0)
return ENOBUFS;
ip6hdr = mtod(m, struct ip6_hdr *);
/* Because we just decremented this in mpls_lse */
ip6hdr->ip6_hlim = ms.shim.ttl + 1;
} else
m_adj(m, sizeof(union mpls_shim));
/* Put it back on IPv6 stack */
schednetisr(NETISR_IPV6);
inq = &ip6intrq;
s = splnet();
if (IF_QFULL(inq)) {
IF_DROP(inq);
splx(s);
m_freem(m);
return ENOBUFS;
}
IF_ENQUEUE(inq, m);
splx(s);
return 0;
}
static struct mbuf *
mpls_label_inet6(struct mbuf *m, union mpls_shim *ms, uint offset)
{
struct ip6_hdr ip6h;
if (mpls_mapttl_inet6 || mpls_mapclass_inet6) {
if (m->m_len < sizeof(struct ip6_hdr) &&
(m = m_pullup(m, offset + sizeof(struct ip6_hdr))) == 0)
return NULL;
m_copydata(m, offset, sizeof(struct ip6_hdr), &ip6h);
if (mpls_mapttl_inet6)
ms->shim.ttl = ip6h.ip6_hlim;
if (mpls_mapclass_inet6)
ms->shim.exp = ip6h.ip6_vfc << 1 >> 5;
}
if ((m = mpls_prepend_shim(m, ms)) == NULL)
return NULL;
return m;
}
#endif /* INET6 */
static struct mbuf *
mpls_prepend_shim(struct mbuf *m, union mpls_shim *ms)
{
union mpls_shim *shim;
M_PREPEND(m, sizeof(*ms), M_DONTWAIT);
if (m == NULL)
return NULL;
if (m->m_len < sizeof(union mpls_shim) &&
(m = m_pullup(m, sizeof(union mpls_shim))) == 0)
return NULL;
shim = mtod(m, union mpls_shim *);
memcpy(shim, ms, sizeof(*shim));
shim->s_addr = htonl(shim->s_addr);
return m;
}