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| author | Rajesh Varatharaj <rvaratharaj@nvidia.com> | 2023-12-29 11:26:43 -0800 |
|---|---|---|
| committer | Rajesh Varatharaj <rvaratharaj@nvidia.com> | 2024-01-11 10:18:03 -0800 |
| commit | 68573c34d40c7503f0b78f1f7188b3ad3e28ae5a (patch) | |
| tree | ec7e48225726e9ce34c9d6093b0711e92cab4592 /bgpd/bgp_network.c | |
| parent | 956b6153fe54754b4e486694addd5a996dea2009 (diff) | |
bgpd: Set correct TTL for the dynamic neighbor peers
In an EBGP multihop configuration with dynamic neighbors, the TTL configured is not being updated for the socket.
Issue:
Assume the following topology:
Host (Dynamic peer to spine - 192.168.1.100) - Leaf - Spine (192.168.1.1)
When the host establishes a BGP multihop session to the spine,
the connection uses the MAXTTL value instead of the configured TTL (in this case, 2).
This issue is only observed with dynamic peers.
Logs: look at the TTL is still MAXTTL, instead of “2” configured.
18:13:18.872395 48:b0:2d:0c:58:0b > 48:b0:2d:66:64:6b, ethertype IPv4 (0x0800), length 85: (tos 0xc0, ttl 255, id 32078, offset 0, flags [DF], proto TCP (6), length 71)
192.168.1.100.179 > 192.168.1.1.40967: Flags [P.], cksum 0xfe89 (correct), seq 28406:28425, ack 28424, win 255, options [nop,nop,TS val 4192664793 ecr 2814447051], length 19: BGP
Keepalive Message (4), length: 19
Fix:
Whenever a dynamic peer is created, the socket TTL should be updated with the configured TTL, in this case 2.
19:13:24.894890 48:b0:2d:0c:58:0b > 48:b0:2d:66:64:6b, ethertype IPv4 (0x0800), length 85: (tos 0xc0, ttl 2, id 1131, offset 0, flags [DF], proto TCP (6), length 71)
192.168.1.100.179 > 192.168.1.1.41937: Flags [P.], cksum 0x7a67 (correct), seq 2046150759:2046150778, ack 4286110599, win 255, options [nop,nop,TS val 4196270815 ecr 2818051226], length 19: BGP
Keepalive Message (4), length: 19
Testing: UT
UT logs:
2023-12-29T19:13:21.892205+00:00 host bgpd[1591425]: [WWPV7-YSZB5] Dynamic Neighbor 192.168.1.1/32 matches group test listen range 192.168.1.0/30
2023-12-29T19:13:21.892654+00:00 host bgpd[1591425]: [GBPAR-M31QF] 192.168.1.1 Dynamic Neighbor added, group test count 1
2023-12-29T19:13:21.892993+00:00 host bgpd[1591425]: [GPE2H-K9QRE] bgp_set_socket_ttl: set TxTTL on peer (rtrid 0.0.0.0) socket, err = 2, peer ttl 2
Conflicts:
bgpd/bgp_network.c
Ticket: #
Signed-off-by: Rajesh Varatharaj <rvaratharaj@nvidia.com>
Diffstat (limited to 'bgpd/bgp_network.c')
| -rw-r--r-- | bgpd/bgp_network.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/bgpd/bgp_network.c b/bgpd/bgp_network.c index e07b18f8fd..dbb34b048f 100644 --- a/bgpd/bgp_network.c +++ b/bgpd/bgp_network.c @@ -484,10 +484,23 @@ static void bgp_accept(struct event *thread) /* Dynamic neighbor has been created, let it proceed */ connection1->fd = bgp_sock; + if (bgp_set_socket_ttl(connection1) < 0) { + peer1->last_reset = PEER_DOWN_SOCKET_ERROR; + zlog_err("%s: Unable to set min/max TTL on peer %s (dynamic), error received: %s(%d)", + __func__, peer1->host, + safe_strerror(errno), errno); + return; + } + /* Set the user configured MSS to TCP socket */ if (CHECK_FLAG(peer1->flags, PEER_FLAG_TCP_MSS)) sockopt_tcp_mss_set(bgp_sock, peer1->tcp_mss); + frr_with_privs (&bgpd_privs) { + vrf_bind(peer1->bgp->vrf_id, bgp_sock, + bgp_get_bound_name(connection1)); + } + bgp_peer_reg_with_nht(peer1); bgp_fsm_change_status(connection1, Active); EVENT_OFF(connection1->t_start); |