[PATCH iproute2 net-next] ipneigh: support for NTF_EXT_LEARNED flag on neigh entries

[Roopa Prabhu <roopa@cumulusnetworks.com>]

From: Roopa Prabhu <roopa@cumulusnetworks.com>

Adds new option extern_learn to set NTF_EXT_LEARNED flag
on neigh entries.

Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
---
 ip/ipneigh.c            | 7 ++++++-
 man/man8/ip-neighbour.8 | 9 ++++++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/ip/ipneigh.c b/ip/ipneigh.c
index 165546e..042d01f 100644
--- a/ip/ipneigh.c
+++ b/ip/ipneigh.c
@@ -48,7 +48,7 @@ static void usage(void)
 {
 	fprintf(stderr, "Usage: ip neigh { add | del | change | replace }\n"
 			"                { ADDR [ lladdr LLADDR ] [ nud STATE ] | proxy ADDR } [ dev DEV ]\n");
-	fprintf(stderr, "                                 [ router ]\n\n");
+	fprintf(stderr, "                                 [ router ] [ extern_learn ]\n\n");
 	fprintf(stderr, "       ip neigh { show | flush } [ proxy ] [ to PREFIX ] [ dev DEV ] [ nud STATE ]\n");
 	fprintf(stderr, "                                 [ vrf NAME ]\n\n");
 	fprintf(stderr, "STATE := { permanent | noarp | stale | reachable | none |\n"
@@ -142,6 +142,8 @@ static int ipneigh_modify(int cmd, int flags, int argc, char **argv)
 			req.ndm.ndm_flags |= NTF_PROXY;
 		} else if (strcmp(*argv, "router") == 0) {
 			req.ndm.ndm_flags |= NTF_ROUTER;
+		} else if (matches(*argv, "extern_learn") == 0) {
+			req.ndm.ndm_flags |= NTF_EXT_LEARNED;
 		} else if (strcmp(*argv, "dev") == 0) {
 			NEXT_ARG();
 			dev = *argv;
@@ -354,6 +356,9 @@ int print_neigh(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
 	if (r->ndm_flags & NTF_PROXY)
 		print_null(PRINT_ANY, "proxy", " %s", "proxy");
 
+	if (r->ndm_flags & NTF_EXT_LEARNED)
+		print_null(PRINT_ANY, "extern_learn", " %s ", "extern_learn");
+
 	if (show_stats) {
 		if (tb[NDA_CACHEINFO])
 			print_cacheinfo(RTA_DATA(tb[NDA_CACHEINFO]));
diff --git a/man/man8/ip-neighbour.8 b/man/man8/ip-neighbour.8
index db286d1..4a672bb 100644
--- a/man/man8/ip-neighbour.8
+++ b/man/man8/ip-neighbour.8
@@ -24,7 +24,8 @@ ip-neighbour \- neighbour/arp tables management.
 .IR ADDR " } [ "
 .B  dev
 .IR DEV " ] [ "
-.BR router " ] "
+.BR router " ] [ "
+.BR extern_learn " ]"
 
 .ti -8
 .BR "ip neigh" " { " show " | " flush " } [ " proxy " ] [ " to
@@ -85,6 +86,12 @@ indicates whether we are proxying for this neigbour entry
 indicates whether neigbour is a router
 
 .TP
+.BI extern_learn
+this neigh entry was learned externally. This option can be used to
+indicate to the kernel that this is a controller learnt dynamic entry.
+Kernel will not gc such an entry.
+
+.TP
 .BI lladdr " LLADDRESS"
 the link layer address of the neighbour.
 .I LLADDRESS
-- 
2.1.4