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pimd: MSDP SA forwarding
* If the MSDP peer receives the SA from a non-RPF peer towards the originating RP, it will drop the message. * SA messages are forwarded away from the RP address only. * SA messages are not forwarded within the mesh group. * Preventing the MSDP connection from being dropped due to RPF check failure (RFC3618, section 13 "MSDP Error Handling") Signed-off-by: Adriano Marto Reis <adrianomarto@gmail.com> Signed-off-by: Adriano Reis <areis@barrukka.local>
This commit is contained in:
Adriano Marto Reis
Donald Sharp
parent
002bac8b5b
commit
9fbd9fc48f
@ -9694,7 +9694,7 @@ static int ip_msdp_peer_cmd_worker(struct pim_instance *pim, struct vty *vty,
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return ret;
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}
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DEFUN_HIDDEN (ip_msdp_peer,
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DEFUN (ip_msdp_peer,
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ip_msdp_peer_cmd,
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"ip msdp peer A.B.C.D source A.B.C.D",
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IP_STR
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@ -9735,7 +9735,7 @@ static int ip_no_msdp_peer_cmd_worker(struct pim_instance *pim, struct vty *vty,
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return result ? CMD_WARNING_CONFIG_FAILED : CMD_SUCCESS;
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}
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DEFUN_HIDDEN (no_ip_msdp_peer,
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DEFUN (no_ip_msdp_peer,
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no_ip_msdp_peer_cmd,
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"no ip msdp peer A.B.C.D",
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NO_STR
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@ -423,6 +423,7 @@ void pim_msdp_sa_ref(struct pim_instance *pim, struct pim_msdp_peer *mp,
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sa->sg_str);
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}
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/* send an immediate SA update to peers */
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sa->rp = pim->msdp.originator_id;
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pim_msdp_pkt_sa_tx_one(sa);
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}
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sa->flags &= ~PIM_MSDP_SAF_STALE;
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@ -721,10 +722,18 @@ static int pim_msdp_sa_comp(const void *p1, const void *p2)
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/* XXX: this can use a bit of refining and extensions */
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bool pim_msdp_peer_rpf_check(struct pim_msdp_peer *mp, struct in_addr rp)
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{
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struct pim_nexthop nexthop;
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if (mp->peer.s_addr == rp.s_addr) {
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return true;
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}
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/* check if the MSDP peer is the nexthop for the RP */
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if (pim_nexthop_lookup(mp->pim, &nexthop, rp, 0)
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&& nexthop.mrib_nexthop_addr.u.prefix4.s_addr == mp->peer.s_addr) {
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return true;
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}
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return false;
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}
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@ -348,7 +348,8 @@ static void pim_msdp_pkt_sa_push(struct pim_instance *pim,
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}
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}
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static int pim_msdp_pkt_sa_fill_hdr(struct pim_instance *pim, int local_cnt)
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static int pim_msdp_pkt_sa_fill_hdr(struct pim_instance *pim, int local_cnt,
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struct in_addr rp)
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{
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int curr_tlv_ecnt;
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@ -361,7 +362,7 @@ static int pim_msdp_pkt_sa_fill_hdr(struct pim_instance *pim, int local_cnt)
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stream_putw(pim->msdp.work_obuf,
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PIM_MSDP_SA_ENTRY_CNT2SIZE(curr_tlv_ecnt));
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stream_putc(pim->msdp.work_obuf, curr_tlv_ecnt);
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stream_put_ipv4(pim->msdp.work_obuf, pim->msdp.originator_id.s_addr);
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stream_put_ipv4(pim->msdp.work_obuf, rp.s_addr);
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return local_cnt;
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}
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@ -387,7 +388,8 @@ static void pim_msdp_pkt_sa_gen(struct pim_instance *pim,
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zlog_debug(" sa gen %d", local_cnt);
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}
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local_cnt = pim_msdp_pkt_sa_fill_hdr(pim, local_cnt);
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local_cnt = pim_msdp_pkt_sa_fill_hdr(pim, local_cnt,
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pim->msdp.originator_id);
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for (ALL_LIST_ELEMENTS_RO(pim->msdp.sa_list, sanode, sa)) {
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if (!(sa->flags & PIM_MSDP_SAF_LOCAL)) {
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@ -408,7 +410,8 @@ static void pim_msdp_pkt_sa_gen(struct pim_instance *pim,
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zlog_debug(" sa gen for remainder %d",
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local_cnt);
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}
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local_cnt = pim_msdp_pkt_sa_fill_hdr(pim, local_cnt);
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local_cnt = pim_msdp_pkt_sa_fill_hdr(
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pim, local_cnt, pim->msdp.originator_id);
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}
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}
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@ -441,7 +444,7 @@ void pim_msdp_pkt_sa_tx(struct pim_instance *pim)
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void pim_msdp_pkt_sa_tx_one(struct pim_msdp_sa *sa)
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{
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pim_msdp_pkt_sa_fill_hdr(sa->pim, 1 /* cnt */);
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pim_msdp_pkt_sa_fill_hdr(sa->pim, 1 /* cnt */, sa->rp);
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pim_msdp_pkt_sa_fill_one(sa);
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pim_msdp_pkt_sa_push(sa->pim, NULL);
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pim_msdp_pkt_sa_tx_done(sa->pim);
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@ -454,6 +457,24 @@ void pim_msdp_pkt_sa_tx_to_one_peer(struct pim_msdp_peer *mp)
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pim_msdp_pkt_sa_tx_done(mp->pim);
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}
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void pim_msdp_pkt_sa_tx_one_to_one_peer(struct pim_msdp_peer *mp,
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struct in_addr rp, struct prefix_sg sg)
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{
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struct pim_msdp_sa sa;
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/* Fills the SA header. */
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pim_msdp_pkt_sa_fill_hdr(mp->pim, 1, rp);
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/* Fills the message contents. */
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sa.pim = mp->pim;
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sa.sg = sg;
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pim_msdp_pkt_sa_fill_one(&sa);
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/* Pushes the message. */
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pim_msdp_pkt_sa_push(sa.pim, mp);
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pim_msdp_pkt_sa_tx_done(sa.pim);
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}
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static void pim_msdp_pkt_rxed_with_fatal_error(struct pim_msdp_peer *mp)
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{
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pim_msdp_peer_reset_tcp_conn(mp, "invalid-pkt-rx");
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@ -473,6 +494,8 @@ static void pim_msdp_pkt_sa_rx_one(struct pim_msdp_peer *mp, struct in_addr rp)
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{
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int prefix_len;
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struct prefix_sg sg;
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struct listnode *peer_node;
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struct pim_msdp_peer *peer;
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/* just throw away the three reserved bytes */
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stream_get3(mp->ibuf);
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@ -493,6 +516,18 @@ static void pim_msdp_pkt_sa_rx_one(struct pim_msdp_peer *mp, struct in_addr rp)
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zlog_debug(" sg %s", pim_str_sg_dump(&sg));
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}
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pim_msdp_sa_ref(mp->pim, mp, &sg, rp);
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/* Forwards the SA to the peers that are not in the RPF to the RP nor in
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* the same mesh group as the peer from which we received the message.
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* If the message group is not set, i.e. "default", then we assume that
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* the message must be forwarded.*/
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for (ALL_LIST_ELEMENTS_RO(mp->pim->msdp.peer_list, peer_node, peer)) {
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if (!pim_msdp_peer_rpf_check(peer, rp)
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&& (strcmp(mp->mesh_group_name, peer->mesh_group_name)
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|| !strcmp(mp->mesh_group_name, "default"))) {
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pim_msdp_pkt_sa_tx_one_to_one_peer(peer, rp, sg);
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}
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}
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}
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static void pim_msdp_pkt_sa_rx(struct pim_msdp_peer *mp, int len)
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@ -510,10 +545,9 @@ static void pim_msdp_pkt_sa_rx(struct pim_msdp_peer *mp, int len)
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entry_cnt = stream_getc(mp->ibuf);
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/* some vendors include the actual multicast data in the tlv (at the
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* end).
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* we will ignore such data. in the future we may consider pushing it
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* down
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* the RPT */
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* end). we will ignore such data. in the future we may consider pushing
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* it down the RPT
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*/
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if (len < PIM_MSDP_SA_ENTRY_CNT2SIZE(entry_cnt)) {
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pim_msdp_pkt_rxed_with_fatal_error(mp);
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return;
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@ -526,6 +560,8 @@ static void pim_msdp_pkt_sa_rx(struct pim_msdp_peer *mp, int len)
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zlog_debug(" entry_cnt %d rp %s", entry_cnt, rp_str);
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}
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pim_msdp_peer_pkt_rxed(mp);
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if (!pim_msdp_peer_rpf_check(mp, rp)) {
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/* if peer-RPF check fails don't process the packet any further
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*/
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@ -535,8 +571,6 @@ static void pim_msdp_pkt_sa_rx(struct pim_msdp_peer *mp, int len)
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return;
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}
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pim_msdp_peer_pkt_rxed(mp);
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/* update SA cache */
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for (i = 0; i < entry_cnt; ++i) {
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pim_msdp_pkt_sa_rx_one(mp, rp);
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@ -67,5 +67,7 @@ int pim_msdp_read(struct thread *thread);
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void pim_msdp_pkt_sa_tx(struct pim_instance *pim);
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void pim_msdp_pkt_sa_tx_one(struct pim_msdp_sa *sa);
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void pim_msdp_pkt_sa_tx_to_one_peer(struct pim_msdp_peer *mp);
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void pim_msdp_pkt_sa_tx_one_to_one_peer(struct pim_msdp_peer *mp,
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struct in_addr rp, struct prefix_sg sg);
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#endif
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