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bfd_packet.c
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/*********************************************************************
* Copyright 2017 Cumulus Networks, Inc. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; see the file COPYING; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* bfd_packet.c: implements the BFD protocol packet handling.
*
* Authors
* -------
* Shrijeet Mukherjee [shm@cumulusnetworks.com]
* Kanna Rajagopal [kanna@cumulusnetworks.com]
* Radhika Mahankali [Radhika@cumulusnetworks.com]
*/
#include <zebra.h>
#ifdef BFD_LINUX
#include <linux/if_packet.h>
#endif /* BFD_LINUX */
#include <netinet/if_ether.h>
#include <netinet/udp.h>
#include "lib/sockopt.h"
#include "bfd.h"
/*
* Prototypes
*/
static int ptm_bfd_process_echo_pkt(struct bfd_vrf_global *bvrf, int s);
int _ptm_bfd_send(struct bfd_session *bs, uint16_t *port, const void *data,
size_t datalen);
static void bfd_sd_reschedule(struct bfd_vrf_global *bvrf, int sd);
ssize_t bfd_recv_ipv4(int sd, uint8_t *msgbuf, size_t msgbuflen, uint8_t *ttl,
ifindex_t *ifindex, struct sockaddr_any *local,
struct sockaddr_any *peer);
ssize_t bfd_recv_ipv6(int sd, uint8_t *msgbuf, size_t msgbuflen, uint8_t *ttl,
ifindex_t *ifindex, struct sockaddr_any *local,
struct sockaddr_any *peer);
int bp_udp_send(int sd, uint8_t ttl, uint8_t *data, size_t datalen,
struct sockaddr *to, socklen_t tolen);
int bp_bfd_echo_in(struct bfd_vrf_global *bvrf, int sd,
uint8_t *ttl, uint32_t *my_discr);
/* socket related prototypes */
static void bp_set_ipopts(int sd);
static void bp_bind_ip(int sd, uint16_t port);
static void bp_set_ipv6opts(int sd);
static void bp_bind_ipv6(int sd, uint16_t port);
/*
* Functions
*/
int _ptm_bfd_send(struct bfd_session *bs, uint16_t *port, const void *data,
size_t datalen)
{
struct sockaddr *sa;
struct sockaddr_in sin;
struct sockaddr_in6 sin6;
socklen_t slen;
ssize_t rv;
int sd = -1;
if (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_IPV6)) {
memset(&sin6, 0, sizeof(sin6));
sin6.sin6_family = AF_INET6;
memcpy(&sin6.sin6_addr, &bs->key.peer, sizeof(sin6.sin6_addr));
if (IN6_IS_ADDR_LINKLOCAL(&sin6.sin6_addr))
sin6.sin6_scope_id = bs->ifp->ifindex;
sin6.sin6_port =
(port) ? *port
: (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_MH))
? htons(BFD_DEF_MHOP_DEST_PORT)
: htons(BFD_DEFDESTPORT);
sd = bs->sock;
sa = (struct sockaddr *)&sin6;
slen = sizeof(sin6);
} else {
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
memcpy(&sin.sin_addr, &bs->key.peer, sizeof(sin.sin_addr));
sin.sin_port =
(port) ? *port
: (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_MH))
? htons(BFD_DEF_MHOP_DEST_PORT)
: htons(BFD_DEFDESTPORT);
sd = bs->sock;
sa = (struct sockaddr *)&sin;
slen = sizeof(sin);
}
#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
sa->sa_len = slen;
#endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
rv = sendto(sd, data, datalen, 0, sa, slen);
if (rv <= 0) {
log_debug("packet-send: send failure: %s", strerror(errno));
return -1;
}
if (rv < (ssize_t)datalen)
log_debug("packet-send: send partial: %s", strerror(errno));
return 0;
}
void ptm_bfd_echo_snd(struct bfd_session *bfd)
{
struct sockaddr *sa;
socklen_t salen;
int sd;
struct bfd_echo_pkt bep;
struct sockaddr_in sin;
struct sockaddr_in6 sin6;
struct bfd_vrf_global *bvrf = bfd_vrf_look_by_session(bfd);
if (!bvrf)
return;
if (!BFD_CHECK_FLAG(bfd->flags, BFD_SESS_FLAG_ECHO_ACTIVE))
BFD_SET_FLAG(bfd->flags, BFD_SESS_FLAG_ECHO_ACTIVE);
memset(&bep, 0, sizeof(bep));
bep.ver = BFD_ECHO_VERSION;
bep.len = BFD_ECHO_PKT_LEN;
bep.my_discr = htonl(bfd->discrs.my_discr);
if (BFD_CHECK_FLAG(bfd->flags, BFD_SESS_FLAG_IPV6)) {
sd = bvrf->bg_echov6;
memset(&sin6, 0, sizeof(sin6));
sin6.sin6_family = AF_INET6;
memcpy(&sin6.sin6_addr, &bfd->key.peer, sizeof(sin6.sin6_addr));
if (bfd->ifp && IN6_IS_ADDR_LINKLOCAL(&sin6.sin6_addr))
sin6.sin6_scope_id = bfd->ifp->ifindex;
sin6.sin6_port = htons(BFD_DEF_ECHO_PORT);
#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
sin6.sin6_len = sizeof(sin6);
#endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
sa = (struct sockaddr *)&sin6;
salen = sizeof(sin6);
} else {
sd = bvrf->bg_echo;
memset(&sin6, 0, sizeof(sin6));
sin.sin_family = AF_INET;
memcpy(&sin.sin_addr, &bfd->key.peer, sizeof(sin.sin_addr));
sin.sin_port = htons(BFD_DEF_ECHO_PORT);
#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
sin.sin_len = sizeof(sin);
#endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
sa = (struct sockaddr *)&sin;
salen = sizeof(sin);
}
if (bp_udp_send(sd, BFD_TTL_VAL, (uint8_t *)&bep, sizeof(bep), sa,
salen)
== -1)
return;
bfd->stats.tx_echo_pkt++;
}
static int ptm_bfd_process_echo_pkt(struct bfd_vrf_global *bvrf, int s)
{
struct bfd_session *bfd;
uint32_t my_discr = 0;
uint8_t ttl = 0;
/* Receive and parse echo packet. */
if (bp_bfd_echo_in(bvrf, s, &ttl, &my_discr) == -1)
return 0;
/* Your discriminator not zero - use it to find session */
bfd = bfd_id_lookup(my_discr);
if (bfd == NULL) {
log_debug("echo-packet: no matching session (id:%u)", my_discr);
return -1;
}
if (!BFD_CHECK_FLAG(bfd->flags, BFD_SESS_FLAG_ECHO_ACTIVE)) {
log_debug("echo-packet: echo disabled [%s] (id:%u)",
bs_to_string(bfd), my_discr);
return -1;
}
bfd->stats.rx_echo_pkt++;
/* Compute detect time */
bfd->echo_detect_TO = bfd->remote_detect_mult * bfd->echo_xmt_TO;
/* Update echo receive timeout. */
if (bfd->echo_detect_TO > 0)
bfd_echo_recvtimer_update(bfd);
return 0;
}
void ptm_bfd_snd(struct bfd_session *bfd, int fbit)
{
struct bfd_pkt cp;
/* Set fields according to section 6.5.7 */
cp.diag = bfd->local_diag;
BFD_SETVER(cp.diag, BFD_VERSION);
cp.flags = 0;
BFD_SETSTATE(cp.flags, bfd->ses_state);
if (BFD_CHECK_FLAG(bfd->flags, BFD_SESS_FLAG_CBIT))
BFD_SETCBIT(cp.flags, BFD_CBIT);
BFD_SETDEMANDBIT(cp.flags, BFD_DEF_DEMAND);
/*
* Polling and Final can't be set at the same time.
*
* RFC 5880, Section 6.5.
*/
BFD_SETFBIT(cp.flags, fbit);
if (fbit == 0)
BFD_SETPBIT(cp.flags, bfd->polling);
cp.detect_mult = bfd->detect_mult;
cp.len = BFD_PKT_LEN;
cp.discrs.my_discr = htonl(bfd->discrs.my_discr);
cp.discrs.remote_discr = htonl(bfd->discrs.remote_discr);
if (bfd->polling) {
cp.timers.desired_min_tx =
htonl(bfd->timers.desired_min_tx);
cp.timers.required_min_rx =
htonl(bfd->timers.required_min_rx);
} else {
/*
* We can only announce current setting on poll, this
* avoids timing mismatch with our peer and give it
* the oportunity to learn. See `bs_final_handler` for
* more information.
*/
cp.timers.desired_min_tx =
htonl(bfd->cur_timers.desired_min_tx);
cp.timers.required_min_rx =
htonl(bfd->cur_timers.required_min_rx);
}
cp.timers.required_min_echo = htonl(bfd->timers.required_min_echo);
if (_ptm_bfd_send(bfd, NULL, &cp, BFD_PKT_LEN) != 0)
return;
bfd->stats.tx_ctrl_pkt++;
}
ssize_t bfd_recv_ipv4(int sd, uint8_t *msgbuf, size_t msgbuflen, uint8_t *ttl,
ifindex_t *ifindex, struct sockaddr_any *local,
struct sockaddr_any *peer)
{
struct cmsghdr *cm;
ssize_t mlen;
struct sockaddr_in msgaddr;
struct msghdr msghdr;
struct iovec iov[1];
uint8_t cmsgbuf[255];
/* Prepare the recvmsg params. */
iov[0].iov_base = msgbuf;
iov[0].iov_len = msgbuflen;
memset(&msghdr, 0, sizeof(msghdr));
msghdr.msg_name = &msgaddr;
msghdr.msg_namelen = sizeof(msgaddr);
msghdr.msg_iov = iov;
msghdr.msg_iovlen = 1;
msghdr.msg_control = cmsgbuf;
msghdr.msg_controllen = sizeof(cmsgbuf);
mlen = recvmsg(sd, &msghdr, MSG_DONTWAIT);
if (mlen == -1) {
if (errno != EAGAIN)
log_error("ipv4-recv: recv failed: %s",
strerror(errno));
return -1;
}
/* Get source address */
peer->sa_sin = *((struct sockaddr_in *)(msghdr.msg_name));
/* Get and check TTL */
for (cm = CMSG_FIRSTHDR(&msghdr); cm != NULL;
cm = CMSG_NXTHDR(&msghdr, cm)) {
if (cm->cmsg_level != IPPROTO_IP)
continue;
switch (cm->cmsg_type) {
#ifdef BFD_LINUX
case IP_TTL: {
uint32_t ttlval;
memcpy(&ttlval, CMSG_DATA(cm), sizeof(ttlval));
if (ttlval > 255) {
log_debug("ipv4-recv: invalid TTL: %u", ttlval);
return -1;
}
*ttl = ttlval;
break;
}
case IP_PKTINFO: {
struct in_pktinfo *pi =
(struct in_pktinfo *)CMSG_DATA(cm);
if (pi == NULL)
break;
local->sa_sin.sin_family = AF_INET;
local->sa_sin.sin_addr = pi->ipi_addr;
#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
local->sa_sin.sin_len = sizeof(local->sa_sin);
#endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
*ifindex = pi->ipi_ifindex;
break;
}
#endif /* BFD_LINUX */
#ifdef BFD_BSD
case IP_RECVTTL: {
memcpy(ttl, CMSG_DATA(cm), sizeof(*ttl));
break;
}
case IP_RECVDSTADDR: {
struct in_addr ia;
memcpy(&ia, CMSG_DATA(cm), sizeof(ia));
local->sa_sin.sin_family = AF_INET;
local->sa_sin.sin_addr = ia;
#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
local->sa_sin.sin_len = sizeof(local->sa_sin);
#endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
break;
}
#endif /* BFD_BSD */
default:
/*
* On *BSDs we expect to land here when skipping
* the IP_RECVIF header. It will be handled by
* getsockopt_ifindex() below.
*/
/* NOTHING */
break;
}
}
/* OS agnostic way of getting interface name. */
if (*ifindex == IFINDEX_INTERNAL)
*ifindex = getsockopt_ifindex(AF_INET, &msghdr);
return mlen;
}
ssize_t bfd_recv_ipv6(int sd, uint8_t *msgbuf, size_t msgbuflen, uint8_t *ttl,
ifindex_t *ifindex, struct sockaddr_any *local,
struct sockaddr_any *peer)
{
struct cmsghdr *cm;
struct in6_pktinfo *pi6 = NULL;
ssize_t mlen;
uint32_t ttlval;
struct sockaddr_in6 msgaddr6;
struct msghdr msghdr6;
struct iovec iov[1];
uint8_t cmsgbuf6[255];
/* Prepare the recvmsg params. */
iov[0].iov_base = msgbuf;
iov[0].iov_len = msgbuflen;
memset(&msghdr6, 0, sizeof(msghdr6));
msghdr6.msg_name = &msgaddr6;
msghdr6.msg_namelen = sizeof(msgaddr6);
msghdr6.msg_iov = iov;
msghdr6.msg_iovlen = 1;
msghdr6.msg_control = cmsgbuf6;
msghdr6.msg_controllen = sizeof(cmsgbuf6);
mlen = recvmsg(sd, &msghdr6, MSG_DONTWAIT);
if (mlen == -1) {
if (errno != EAGAIN)
log_error("ipv6-recv: recv failed: %s",
strerror(errno));
return -1;
}
/* Get source address */
peer->sa_sin6 = *((struct sockaddr_in6 *)(msghdr6.msg_name));
/* Get and check TTL */
for (cm = CMSG_FIRSTHDR(&msghdr6); cm != NULL;
cm = CMSG_NXTHDR(&msghdr6, cm)) {
if (cm->cmsg_level != IPPROTO_IPV6)
continue;
if (cm->cmsg_type == IPV6_HOPLIMIT) {
memcpy(&ttlval, CMSG_DATA(cm), sizeof(ttlval));
if (ttlval > 255) {
log_debug("ipv6-recv: invalid TTL: %u", ttlval);
return -1;
}
*ttl = ttlval;
} else if (cm->cmsg_type == IPV6_PKTINFO) {
pi6 = (struct in6_pktinfo *)CMSG_DATA(cm);
if (pi6) {
local->sa_sin6.sin6_family = AF_INET6;
local->sa_sin6.sin6_addr = pi6->ipi6_addr;
#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
local->sa_sin6.sin6_len = sizeof(local->sa_sin6);
#endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
*ifindex = pi6->ipi6_ifindex;
/* Set scope ID for link local addresses. */
if (IN6_IS_ADDR_LINKLOCAL(
&peer->sa_sin6.sin6_addr))
peer->sa_sin6.sin6_scope_id = *ifindex;
if (IN6_IS_ADDR_LINKLOCAL(
&local->sa_sin6.sin6_addr))
local->sa_sin6.sin6_scope_id = *ifindex;
}
}
}
return mlen;
}
static void bfd_sd_reschedule(struct bfd_vrf_global *bvrf, int sd)
{
if (sd == bvrf->bg_shop) {
THREAD_OFF(bvrf->bg_ev[0]);
thread_add_read(master, bfd_recv_cb, bvrf, bvrf->bg_shop,
&bvrf->bg_ev[0]);
} else if (sd == bvrf->bg_mhop) {
THREAD_OFF(bvrf->bg_ev[1]);
thread_add_read(master, bfd_recv_cb, bvrf, bvrf->bg_mhop,
&bvrf->bg_ev[1]);
} else if (sd == bvrf->bg_shop6) {
THREAD_OFF(bvrf->bg_ev[2]);
thread_add_read(master, bfd_recv_cb, bvrf, bvrf->bg_shop6,
&bvrf->bg_ev[2]);
} else if (sd == bvrf->bg_mhop6) {
THREAD_OFF(bvrf->bg_ev[3]);
thread_add_read(master, bfd_recv_cb, bvrf, bvrf->bg_mhop6,
&bvrf->bg_ev[3]);
} else if (sd == bvrf->bg_echo) {
THREAD_OFF(bvrf->bg_ev[4]);
thread_add_read(master, bfd_recv_cb, bvrf, bvrf->bg_echo,
&bvrf->bg_ev[4]);
} else if (sd == bvrf->bg_echov6) {
THREAD_OFF(bvrf->bg_ev[5]);
thread_add_read(master, bfd_recv_cb, bvrf, bvrf->bg_echov6,
&bvrf->bg_ev[5]);
}
}
static void cp_debug(bool mhop, struct sockaddr_any *peer,
struct sockaddr_any *local, ifindex_t ifindex,
vrf_id_t vrfid, const char *fmt, ...)
{
char buf[512], peerstr[128], localstr[128], portstr[64], vrfstr[64];
va_list vl;
if (peer->sa_sin.sin_family)
snprintf(peerstr, sizeof(peerstr), " peer:%s", satostr(peer));
else
peerstr[0] = 0;
if (local->sa_sin.sin_family)
snprintf(localstr, sizeof(localstr), " local:%s",
satostr(local));
else
localstr[0] = 0;
if (ifindex != IFINDEX_INTERNAL)
snprintf(portstr, sizeof(portstr), " port:%u", ifindex);
else
portstr[0] = 0;
if (vrfid != VRF_DEFAULT)
snprintf(vrfstr, sizeof(vrfstr), " vrf:%u", vrfid);
else
vrfstr[0] = 0;
va_start(vl, fmt);
vsnprintf(buf, sizeof(buf), fmt, vl);
va_end(vl);
log_debug("control-packet: %s [mhop:%s%s%s%s%s]", buf,
mhop ? "yes" : "no", peerstr, localstr, portstr, vrfstr);
}
int bfd_recv_cb(struct thread *t)
{
int sd = THREAD_FD(t);
struct bfd_session *bfd;
struct bfd_pkt *cp;
bool is_mhop;
ssize_t mlen = 0;
uint8_t ttl = 0;
vrf_id_t vrfid;
ifindex_t ifindex = IFINDEX_INTERNAL;
struct sockaddr_any local, peer;
uint8_t msgbuf[1516];
struct bfd_vrf_global *bvrf = THREAD_ARG(t);
vrfid = bvrf->vrf->vrf_id;
/* Schedule next read. */
bfd_sd_reschedule(bvrf, sd);
/* Handle echo packets. */
if (sd == bvrf->bg_echo || sd == bvrf->bg_echov6) {
ptm_bfd_process_echo_pkt(bvrf, sd);
return 0;
}
/* Sanitize input/output. */
memset(&local, 0, sizeof(local));
memset(&peer, 0, sizeof(peer));
/* Handle control packets. */
is_mhop = false;
if (sd == bvrf->bg_shop || sd == bvrf->bg_mhop) {
is_mhop = sd == bvrf->bg_mhop;
mlen = bfd_recv_ipv4(sd, msgbuf, sizeof(msgbuf), &ttl, &ifindex,
&local, &peer);
} else if (sd == bvrf->bg_shop6 || sd == bvrf->bg_mhop6) {
is_mhop = sd == bvrf->bg_mhop6;
mlen = bfd_recv_ipv6(sd, msgbuf, sizeof(msgbuf), &ttl, &ifindex,
&local, &peer);
}
/* Implement RFC 5880 6.8.6 */
if (mlen < BFD_PKT_LEN) {
cp_debug(is_mhop, &peer, &local, ifindex, vrfid,
"too small (%ld bytes)", mlen);
return 0;
}
/* Validate packet TTL. */
if ((!is_mhop) && (ttl != BFD_TTL_VAL)) {
cp_debug(is_mhop, &peer, &local, ifindex, vrfid,
"invalid TTL: %d expected %d", ttl, BFD_TTL_VAL);
return 0;
}
/*
* Parse the control header for inconsistencies:
* - Invalid version;
* - Bad multiplier configuration;
* - Short packets;
* - Invalid discriminator;
*/
cp = (struct bfd_pkt *)(msgbuf);
if (BFD_GETVER(cp->diag) != BFD_VERSION) {
cp_debug(is_mhop, &peer, &local, ifindex, vrfid,
"bad version %d", BFD_GETVER(cp->diag));
return 0;
}
if (cp->detect_mult == 0) {
cp_debug(is_mhop, &peer, &local, ifindex, vrfid,
"detect multiplier set to zero");
return 0;
}
if ((cp->len < BFD_PKT_LEN) || (cp->len > mlen)) {
cp_debug(is_mhop, &peer, &local, ifindex, vrfid, "too small");
return 0;
}
if (cp->discrs.my_discr == 0) {
cp_debug(is_mhop, &peer, &local, ifindex, vrfid,
"'my discriminator' is zero");
return 0;
}
/* Find the session that this packet belongs. */
bfd = ptm_bfd_sess_find(cp, &peer, &local, ifindex, vrfid, is_mhop);
if (bfd == NULL) {
cp_debug(is_mhop, &peer, &local, ifindex, vrfid,
"no session found");
return 0;
}
bfd->stats.rx_ctrl_pkt++;
/*
* Multi hop: validate packet TTL.
* Single hop: set local address that received the packet.
*/
if (is_mhop) {
if ((BFD_TTL_VAL - bfd->mh_ttl) > BFD_TTL_VAL) {
cp_debug(is_mhop, &peer, &local, ifindex, vrfid,
"exceeded max hop count (expected %d, got %d)",
bfd->mh_ttl, BFD_TTL_VAL);
return 0;
}
} else if (bfd->local_address.sa_sin.sin_family == AF_UNSPEC) {
bfd->local_address = local;
}
/*
* If no interface was detected, save the interface where the
* packet came in.
*/
if (bfd->ifp == NULL)
bfd->ifp = if_lookup_by_index(ifindex, vrfid);
/* Log remote discriminator changes. */
if ((bfd->discrs.remote_discr != 0)
&& (bfd->discrs.remote_discr != ntohl(cp->discrs.my_discr)))
cp_debug(is_mhop, &peer, &local, ifindex, vrfid,
"remote discriminator mismatch (expected %u, got %u)",
bfd->discrs.remote_discr, ntohl(cp->discrs.my_discr));
bfd->discrs.remote_discr = ntohl(cp->discrs.my_discr);
/* Save remote diagnostics before state switch. */
bfd->remote_diag = cp->diag & BFD_DIAGMASK;
/* Update remote timers settings. */
bfd->remote_timers.desired_min_tx = ntohl(cp->timers.desired_min_tx);
bfd->remote_timers.required_min_rx = ntohl(cp->timers.required_min_rx);
bfd->remote_timers.required_min_echo =
ntohl(cp->timers.required_min_echo);
bfd->remote_detect_mult = cp->detect_mult;
if (BFD_GETCBIT(cp->flags))
bfd->remote_cbit = 1;
else
bfd->remote_cbit = 0;
/* State switch from section 6.2. */
bs_state_handler(bfd, BFD_GETSTATE(cp->flags));
/* RFC 5880, Section 6.5: handle POLL/FINAL negotiation sequence. */
if (bfd->polling && BFD_GETFBIT(cp->flags)) {
/* Disable pooling. */
bfd->polling = 0;
/* Handle poll finalization. */
bs_final_handler(bfd);
} else {
/* Received a packet, lets update the receive timer. */
bfd_recvtimer_update(bfd);
}
/* Handle echo timers changes. */
bs_echo_timer_handler(bfd);
/*
* We've received a packet with the POLL bit set, we must send
* a control packet back with the FINAL bit set.
*
* RFC 5880, Section 6.5.
*/
if (BFD_GETPBIT(cp->flags)) {
/* We are finalizing a poll negotiation. */
bs_final_handler(bfd);
/* Send the control packet with the final bit immediately. */
ptm_bfd_snd(bfd, 1);
}
return 0;
}
/*
* bp_bfd_echo_in: proccesses an BFD echo packet. On TTL == BFD_TTL_VAL
* the packet is looped back or returns the my discriminator ID along
* with the TTL.
*
* Returns -1 on error or loopback or 0 on success.
*/
int bp_bfd_echo_in(struct bfd_vrf_global *bvrf, int sd,
uint8_t *ttl, uint32_t *my_discr)
{
struct bfd_echo_pkt *bep;
ssize_t rlen;
struct sockaddr_any local, peer;
ifindex_t ifindex = IFINDEX_INTERNAL;
vrf_id_t vrfid = VRF_DEFAULT;
uint8_t msgbuf[1516];
if (sd == bvrf->bg_echo)
rlen = bfd_recv_ipv4(sd, msgbuf, sizeof(msgbuf), ttl, &ifindex,
&local, &peer);
else
rlen = bfd_recv_ipv6(sd, msgbuf, sizeof(msgbuf), ttl, &ifindex,
&local, &peer);
/* Short packet, better not risk reading it. */
if (rlen < (ssize_t)sizeof(*bep)) {
cp_debug(false, &peer, &local, ifindex, vrfid,
"small echo packet");
return -1;
}
/* Test for loopback. */
if (*ttl == BFD_TTL_VAL) {
bp_udp_send(sd, *ttl - 1, msgbuf, rlen,
(struct sockaddr *)&peer,
(sd == bvrf->bg_echo) ? sizeof(peer.sa_sin)
: sizeof(peer.sa_sin6));
return -1;
}
/* Read my discriminator from BFD Echo packet. */
bep = (struct bfd_echo_pkt *)msgbuf;
*my_discr = ntohl(bep->my_discr);
if (*my_discr == 0) {
cp_debug(false, &peer, &local, ifindex, vrfid,
"invalid echo packet discriminator (zero)");
return -1;
}
return 0;
}
int bp_udp_send(int sd, uint8_t ttl, uint8_t *data, size_t datalen,
struct sockaddr *to, socklen_t tolen)
{
struct cmsghdr *cmsg;
ssize_t wlen;
int ttlval = ttl;
bool is_ipv6 = to->sa_family == AF_INET6;
struct msghdr msg;
struct iovec iov[1];
uint8_t msgctl[255];
/* Prepare message data. */
iov[0].iov_base = data;
iov[0].iov_len = datalen;
memset(&msg, 0, sizeof(msg));
memset(msgctl, 0, sizeof(msgctl));
msg.msg_name = to;
msg.msg_namelen = tolen;
msg.msg_iov = iov;
msg.msg_iovlen = 1;
/* Prepare the packet TTL information. */
if (ttl > 0) {
/* Use ancillary data. */
msg.msg_control = msgctl;
msg.msg_controllen = CMSG_LEN(sizeof(ttlval));
/* Configure the ancillary data. */
cmsg = CMSG_FIRSTHDR(&msg);
cmsg->cmsg_len = CMSG_LEN(sizeof(ttlval));
if (is_ipv6) {
cmsg->cmsg_level = IPPROTO_IPV6;
cmsg->cmsg_type = IPV6_HOPLIMIT;
} else {
#if BFD_LINUX
cmsg->cmsg_level = IPPROTO_IP;
cmsg->cmsg_type = IP_TTL;
#else
/* FreeBSD does not support TTL in ancillary data. */
msg.msg_control = NULL;
msg.msg_controllen = 0;
bp_set_ttl(sd, ttl);
#endif /* BFD_BSD */
}
memcpy(CMSG_DATA(cmsg), &ttlval, sizeof(ttlval));
}
/* Send echo back. */
wlen = sendmsg(sd, &msg, 0);
if (wlen <= 0) {
log_debug("udp-send: loopback failure: (%d) %s", errno, strerror(errno));
return -1;
} else if (wlen < (ssize_t)datalen) {
log_debug("udp-send: partial send: %zd expected %zu", wlen,
datalen);
return -1;
}
return 0;
}
/*
* Sockets creation.
*/
/*
* IPv4 sockets
*/
int bp_set_ttl(int sd, uint8_t value)
{
int ttl = value;
if (setsockopt(sd, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl)) == -1) {
log_warning("set-ttl: setsockopt(IP_TTL, %d): %s", value,
strerror(errno));
return -1;
}
return 0;
}
int bp_set_tos(int sd, uint8_t value)
{
int tos = value;
if (setsockopt(sd, IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) == -1) {
log_warning("set-tos: setsockopt(IP_TOS, %d): %s", value,
strerror(errno));
return -1;
}
return 0;
}
static void bp_set_ipopts(int sd)
{
int rcvttl = BFD_RCV_TTL_VAL;
if (bp_set_ttl(sd, BFD_TTL_VAL) != 0)
log_fatal("set-ipopts: TTL configuration failed");
if (setsockopt(sd, IPPROTO_IP, IP_RECVTTL, &rcvttl, sizeof(rcvttl))
== -1)
log_fatal("set-ipopts: setsockopt(IP_RECVTTL, %d): %s", rcvttl,
strerror(errno));
#ifdef BFD_LINUX
int pktinfo = BFD_PKT_INFO_VAL;
/* Figure out address and interface to do the peer matching. */
if (setsockopt(sd, IPPROTO_IP, IP_PKTINFO, &pktinfo, sizeof(pktinfo))
== -1)
log_fatal("set-ipopts: setsockopt(IP_PKTINFO, %d): %s", pktinfo,
strerror(errno));
#endif /* BFD_LINUX */
#ifdef BFD_BSD
int yes = 1;
/* Find out our address for peer matching. */
if (setsockopt(sd, IPPROTO_IP, IP_RECVDSTADDR, &yes, sizeof(yes)) == -1)
log_fatal("set-ipopts: setsockopt(IP_RECVDSTADDR, %d): %s", yes,
strerror(errno));
/* Find out interface where the packet came in. */
if (setsockopt_ifindex(AF_INET, sd, yes) == -1)
log_fatal("set-ipopts: setsockopt_ipv4_ifindex(%d): %s", yes,
strerror(errno));
#endif /* BFD_BSD */
}
static void bp_bind_ip(int sd, uint16_t port)
{
struct sockaddr_in sin;
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = htonl(INADDR_ANY);
sin.sin_port = htons(port);
if (bind(sd, (struct sockaddr *)&sin, sizeof(sin)) == -1)
log_fatal("bind-ip: bind: %s", strerror(errno));
}
int bp_udp_shop(const struct vrf *vrf)
{
int sd;
frr_with_privs(&bglobal.bfdd_privs) {
sd = vrf_socket(AF_INET, SOCK_DGRAM, PF_UNSPEC, vrf->vrf_id,
vrf->name);
}
if (sd == -1)
log_fatal("udp-shop: socket: %s", strerror(errno));
bp_set_ipopts(sd);
bp_bind_ip(sd, BFD_DEFDESTPORT);
return sd;
}
int bp_udp_mhop(const struct vrf *vrf)
{
int sd;
frr_with_privs(&bglobal.bfdd_privs) {
sd = vrf_socket(AF_INET, SOCK_DGRAM, PF_UNSPEC, vrf->vrf_id,
vrf->name);
}
if (sd == -1)
log_fatal("udp-mhop: socket: %s", strerror(errno));
bp_set_ipopts(sd);
bp_bind_ip(sd, BFD_DEF_MHOP_DEST_PORT);
return sd;
}
int bp_peer_socket(const struct bfd_session *bs)
{
int sd, pcount;
struct sockaddr_in sin;
static int srcPort = BFD_SRCPORTINIT;
const char *device_to_bind = NULL;
if (bs->key.ifname[0])
device_to_bind = (const char *)bs->key.ifname;
else if (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_MH)
&& bs->key.vrfname[0])
device_to_bind = (const char *)bs->key.vrfname;
frr_with_privs(&bglobal.bfdd_privs) {
sd = vrf_socket(AF_INET, SOCK_DGRAM, PF_UNSPEC,
bs->vrf->vrf_id, device_to_bind);
}
if (sd == -1) {
log_error("ipv4-new: failed to create socket: %s",
strerror(errno));
return -1;
}
/* Set TTL to 255 for all transmitted packets */
if (bp_set_ttl(sd, BFD_TTL_VAL) != 0) {
close(sd);
return -1;
}
/* Set TOS to CS6 for all transmitted packets */
if (bp_set_tos(sd, BFD_TOS_VAL) != 0) {
close(sd);
return -1;
}
/* Find an available source port in the proper range */
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
sin.sin_len = sizeof(sin);
#endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
memcpy(&sin.sin_addr, &bs->key.local, sizeof(sin.sin_addr));
if (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_MH) == 0)
sin.sin_addr.s_addr = INADDR_ANY;
pcount = 0;
do {
if ((++pcount) > (BFD_SRCPORTMAX - BFD_SRCPORTINIT)) {
/* Searched all ports, none available */
log_error("ipv4-new: failed to bind port: %s",
strerror(errno));
close(sd);
return -1;
}
if (srcPort >= BFD_SRCPORTMAX)
srcPort = BFD_SRCPORTINIT;
sin.sin_port = htons(srcPort++);
} while (bind(sd, (struct sockaddr *)&sin, sizeof(sin)) < 0);
return sd;
}
/*
* IPv6 sockets
*/
int bp_peer_socketv6(const struct bfd_session *bs)
{
int sd, pcount;
struct sockaddr_in6 sin6;
static int srcPort = BFD_SRCPORTINIT;
const char *device_to_bind = NULL;
if (bs->key.ifname[0])