Re: [PATCH v2 iproute2 net-next 2/2] iproute: Add support for MPLS LWT ttl attribute

[David Ahern]

On 4/11/17 2:37 AM, Robert Shearman wrote:
> Add support for setting and displaying the ttl attribute
> for MPLS IP lighweight tunnels.
> 
> Signed-off-by: Robert Shearman 
> ---
>  ip/iproute_lwtunnel.c  | 31 +--
>  man/man8/ip-route.8.in |  9 -
>  2 files changed, 37 insertions(+), 3 deletions(-)
> 

Acked-by: David Ahern 

[PATCH v2 iproute2 net-next 2/2] iproute: Add support for MPLS LWT ttl attribute

[Robert Shearman]

Add support for setting and displaying the ttl attribute
for MPLS IP lighweight tunnels.

Signed-off-by: Robert Shearman 
---
 ip/iproute_lwtunnel.c  | 31 +--
 man/man8/ip-route.8.in |  9 -
 2 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/ip/iproute_lwtunnel.c b/ip/iproute_lwtunnel.c
index 0fa1cab0a790..845a115e9e41 100644
--- a/ip/iproute_lwtunnel.c
+++ b/ip/iproute_lwtunnel.c
@@ -84,6 +84,9 @@ static void print_encap_mpls(FILE *fp, struct rtattr *encap)
if (tb[MPLS_IPTUNNEL_DST])
fprintf(fp, " %s ",
format_host_rta(AF_MPLS, tb[MPLS_IPTUNNEL_DST]));
+   if (tb[MPLS_IPTUNNEL_TTL])
+   fprintf(fp, "ttl %u ",
+   rta_getattr_u8(tb[MPLS_IPTUNNEL_TTL]));
 }
 
 static void print_encap_ip(FILE *fp, struct rtattr *encap)
@@ -247,6 +250,7 @@ static int parse_encap_mpls(struct rtattr *rta, size_t len,
inet_prefix addr;
int argc = *argcp;
char **argv = *argvp;
+   int ttl_ok = 0;
 
if (get_addr(, *argv, AF_MPLS)) {
fprintf(stderr,
@@ -258,8 +262,31 @@ static int parse_encap_mpls(struct rtattr *rta, size_t len,
rta_addattr_l(rta, len, MPLS_IPTUNNEL_DST, ,
  addr.bytelen);
 
-   *argcp = argc;
-   *argvp = argv;
+   argc--;
+   argv++;
+
+   while (argc > 0) {
+   if (strcmp(*argv, "ttl") == 0) {
+   __u8 ttl;
+
+   NEXT_ARG();
+   if (ttl_ok++)
+   duparg2("ttl", *argv);
+   if (get_u8(, *argv, 0))
+   invarg("\"ttl\" value is invalid\n", *argv);
+   rta_addattr8(rta, len, MPLS_IPTUNNEL_TTL, ttl);
+   } else {
+   break;
+   }
+   argc--; argv++;
+   }
+
+   /* argv is currently the first unparsed argument,
+* but the lwt_parse_encap() caller will move to the next,
+* so step back
+*/
+   *argcp = argc + 1;
+   *argvp = argv - 1;
 
return 0;
 }
diff --git a/man/man8/ip-route.8.in b/man/man8/ip-route.8.in
index fbe2711a4301..d2a44acf2793 100644
--- a/man/man8/ip-route.8.in
+++ b/man/man8/ip-route.8.in
@@ -181,7 +181,9 @@ throw " | " unreachable " | " prohibit " | " blackhole " | 
" nat " ]"
 .ti -8
 .IR ENCAP_MPLS " := "
 .BR mpls " [ "
-.IR LABEL " ]"
+.IR LABEL " ] ["
+.B  ttl
+.IR TTL " ]"
 
 .ti -8
 .IR ENCAP_IP " := "
@@ -666,6 +668,11 @@ is a set of encapsulation attributes specific to the
 .I MPLSLABEL
 - mpls label stack with labels separated by
 .I "/"
+.sp
+
+.B ttl
+.I TTL
+- TTL to use for MPLS header or 0 to inherit from IP header
 .in -2
 .sp
 
-- 
2.1.4