diff options
Diffstat (limited to 'ldpd/neighbor.c')
| -rw-r--r-- | ldpd/neighbor.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/ldpd/neighbor.c b/ldpd/neighbor.c index d40728b..2596c79 100644 --- a/ldpd/neighbor.c +++ b/ldpd/neighbor.c @@ -681,6 +681,18 @@ nbr_gtsm_setup(int fd, int af, struct nbr_params *nbrp) if (nbrp && CHECK_FLAG(nbrp->flags, F_NBRP_GTSM_HOPS)) ttl = 256 - nbrp->gtsm_hops; + /* + * In linux networking stack, the received mpls packets + * will be processed by the host twice, one as mpls packet, + * the other as ip packet, so its ttl will be decreased 1. + * This behavior is based on the new kernel (5.10 and 6.1), + * and older versions may behave differently. + * + * Here, decrease 1 for IP_MINTTL if GTSM is enabled. + * And this workaround makes the GTSM mechanism a bit deviation. + */ + ttl -= 1; + switch (af) { case AF_INET: if (sock_set_ipv4_minttl(fd, ttl) == -1) |