ripd: add non-zero check for RIPv1 reserved field,

According to RFC2453 3.6, the tag of a RIP-1 entry should be zero
Signed-off-by: zmw12306 <zmw12306@gmail.com>

diff --git a/ripd/ripd.c b/ripd/ripd.c
index fb3d574aaa70b71459875455c989610ef1233e7b..9167a4fa700af6615eb124fa92dd39b0ecb32a1e 100644 (file)
--- a/ripd/ripd.c
+++ b/ripd/ripd.c
@@ -1171,6 +1171,12 @@ static void rip_response_process(struct rip_packet *packet, int size,
                        continue;
                }
 
+               if (packet->version == RIPv1 && rte->tag != 0) {
+                       zlog_warn("RIPv1 reserved field is nonzero: %d",
+                                 ntohs(rte->tag));
+                       continue;
+               }
+
                /* - is the destination address valid (e.g., unicast; not net 0
                   or 127) */
                if (!rip_destination_check(rte->prefix)) {