From a59166e470868d92f0813977817e99e699398af5 Mon Sep 17 00:00:00 2001 From: Robert Shearman Date: Fri, 10 Mar 2017 20:43:25 +0000 Subject: mpls: allow TTL propagation from IP packets to be configured Allow TTL propagation from IP packets to MPLS packets to be configured. Add a new optional LWT attribute, MPLS_IPTUNNEL_TTL, which allows the TTL to be set in the resulting MPLS packet, with the value of 0 having the semantics of enabling propagation of the TTL from the IP header (i.e. non-zero values disable propagation). Also allow the configuration to be overridden globally by reusing the same sysctl to control whether the TTL is propagated from IP packets into the MPLS header. If the per-LWT attribute is set then it overrides the global configuration. If the TTL isn't propagated then a default TTL value is used which can be configured via a new sysctl, "net.mpls.default_ttl". This is kept separate from the configuration of whether IP TTL propagation is enabled as it can be used in the future when non-IP payloads are supported (i.e. where there is no payload TTL that can be propagated). Signed-off-by: Robert Shearman Acked-by: David Ahern Tested-by: David Ahern Signed-off-by: David S. Miller --- net/mpls/af_mpls.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'net/mpls/af_mpls.c') diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c index 0e1046f21af8..0c5d111abe36 100644 --- a/net/mpls/af_mpls.c +++ b/net/mpls/af_mpls.c @@ -34,6 +34,7 @@ static int zero = 0; static int one = 1; static int label_limit = (1 << 20) - 1; +static int ttl_max = 255; static void rtmsg_lfib(int event, u32 label, struct mpls_route *rt, struct nlmsghdr *nlh, struct net *net, u32 portid, @@ -2042,6 +2043,15 @@ static const struct ctl_table mpls_table[] = { .extra1 = &zero, .extra2 = &one, }, + { + .procname = "default_ttl", + .data = MPLS_NS_SYSCTL_OFFSET(mpls.default_ttl), + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = &one, + .extra2 = &ttl_max, + }, { } }; @@ -2053,6 +2063,7 @@ static int mpls_net_init(struct net *net) net->mpls.platform_labels = 0; net->mpls.platform_label = NULL; net->mpls.ip_ttl_propagate = 1; + net->mpls.default_ttl = 255; table = kmemdup(mpls_table, sizeof(mpls_table), GFP_KERNEL); if (table == NULL) -- cgit v1.2.3