Hi Mitchell
Thanks a lot for the work you are putting into BFD, I'll be able to
review this properly over the weekend.
-peter
On 2019 Jun 03 (Mon) at 20:37:17 +1000 (+1000), Mitchell Krome wrote:
:Hi,
:
:Testing bfd against frr on linux, their bfd implementation sends polls
:as soon as the session is up even if the session timers haven't
:changed from what it was advertising while it was in the down state.
:Currently openbsd bfd doesn't respond to polls, so this diff adds that
:support. tcpdump output during session setup (.9 is openbsd):
:
:14:56:31.225339 10.10.20.9.58974 > 10.10.20.10.bfd-control: [udp sum ok] BFD
v1 length 24 state down flags [] diag none my-discrim 3396727743 your-discrim 0
mintx 1000000 minrx 1000000 minecho 0 multiplier 3 [to s 0xc0] (ttl 255, id
48014, len 52)
:14:56:31.533645 10.10.20.10.49143 > 10.10.20.9.bfd-control: [udp sum ok] BFD
v1 length 24 state init flags [] diag neighbor-down my-discrim 2 your-discrim
3396727743 mintx 1500000 minrx 1500000 minecho 50000 mul tiplier 3 (DF) [tos
0xc0] (ttl 255, id 36838, len 52)
:14:56:32.022601 10.10.20.9.58974 > 10.10.20.10.bfd-control: [udp sum ok] BFD
v1 length 24 state up flags [] diag none my-discrim 3396727743 your-discrim 2
mintx 1000000 minrx 1500000 minecho 0 multiplier 3 [tos 0xc0] (ttl 255, id
21474, len 52)
:14:56:32.023134 10.10.20.10.49143 > 10.10.20.9.bfd-control: [udp sum ok] BFD
v1 length 24 state up flags [P] diag none my-discrim 2 your-discrim 3396727743
mintx 1500000 minrx 1500000 minecho 50000 multiplier 3 (DF) [tos 0xc0] (ttl
255, id 36952, len 52)
:14:56:32.023207 10.10.20.9.58974 > 10.10.20.10.bfd-control: [udp sum ok] BFD
v1 length 24 state up flags [F] diag none my-discrim 3396727743 your-discrim 2
mintx 1500000 minrx 1500000 minecho 0 multiplier 3 [tos 0xc0] (ttl 255, id
23805, len 52)
:14:56:32.997091 10.10.20.10.49143 > 10.10.20.9.bfd-control: [udp sum ok] BFD
v1 length 24 state up flags [] diag none my-discrim 2 your-discrim 3396727743
mintx 1500000 minrx 1500000 minecho 50000 multiplier 3 ( DF) [tos 0xc0] (ttl
255, id 36991, len 52)
:
:I also added some handling for generating polls and receiving finals while
:in there, but there isn't any code to actually start our own poll
:sequence just yet.
:
:I only have frr and openbsd peers to test with - if anybody has
:something else hooked up would be good to check what they do.
:
:Mitchell
:
:
:diff --git sys/net/bfd.c sys/net/bfd.c
:index 42995531a8a..2ae287a15bb 100644
:--- sys/net/bfd.c
:+++ sys/net/bfd.c
:@@ -741,6 +741,8 @@ bfd_reset(struct bfd_config *bfd)
:
: bfd->bc_mode = BFD_MODE_ASYNC;
: bfd->bc_state = BFD_STATE_DOWN;
:+ bfd->bc_poll_seq = 0;
:+ bfd->bc_poll_rcvd = 0;
:
: /* rfc5880 6.8.18 */
: bfd->bc_neighbor->bn_lstate = BFD_STATE_DOWN;
:@@ -825,7 +827,10 @@ bfd_input(struct bfd_config *bfd, struct mbuf *m)
: bfd->bc_neighbor->bn_rdiscr = ntohl(peer->bfd_my_discriminator);
: bfd->bc_neighbor->bn_rstate = state;
: bfd->bc_neighbor->bn_rdemand = (flags & BFD_FLAG_D);
:- bfd->bc_poll = (flags & BFD_FLAG_F);
:+
:+ if (flags & BFD_FLAG_F && bfd->bc_poll_seq) {
:+ bfd->bc_poll_seq = 0;
:+ }
:
: /* Local change to the algorithm, we don't accept below 50ms */
: if (ntohl(peer->bfd_required_min_rx_interval) < BFD_MINIMUM)
:@@ -891,6 +896,12 @@ bfd_input(struct bfd_config *bfd, struct mbuf *m)
:
: bfd->bc_error = 0;
:
:+ /* Reply to poll if we aren't down */
:+ if (flags & BFD_FLAG_P && bfd->bc_state > BFD_STATE_DOWN) {
:+ bfd->bc_poll_rcvd = 1;
:+ bfd_send_control(bfd);
:+ }
:+
: discard:
: bfd->bc_neighbor->bn_rdiag = diag;
: m_free(m);
:@@ -979,6 +990,13 @@ bfd_send_control(void *x)
:
: h->bfd_ver_diag = ((BFD_VERSION << 5) | (bfd->bc_neighbor->bn_ldiag));
: h->bfd_sta_flags = (bfd->bc_state << 6);
:+ /* Can't send a poll and a final in the same packet. */
:+ if (bfd->bc_poll_rcvd) {
:+ h->bfd_sta_flags |= BFD_FLAG_F;
:+ bfd->bc_poll_rcvd = 0;
:+ } else if (bfd->bc_poll_seq) {
:+ h->bfd_sta_flags |= BFD_FLAG_P;
:+ }
: h->bfd_detect_multi = bfd->bc_neighbor->bn_mult;
: h->bfd_length = BFD_HDRLEN;
: h->bfd_my_discriminator = htonl(bfd->bc_neighbor->bn_ldiscr);
:diff --git sys/net/bfd.h sys/net/bfd.h
:index 3e8da45086f..8ee372faa5d 100644
:--- sys/net/bfd.h
:+++ sys/net/bfd.h
:@@ -143,7 +143,8 @@ struct bfd_config {
: time_t bc_lastuptime;
: unsigned int bc_laststate;
: unsigned int bc_state;
:- unsigned int bc_poll;
:+ unsigned int bc_poll_seq;
:+ unsigned int bc_poll_rcvd;
: unsigned int bc_error;
: uint32_t bc_minrx;
: uint32_t bc_mintx;
:
--
Philosophy will clip an angel's wings.
-- John Keats
