zebra: Note when the netlink DUMP command is interrupted

There exists code paths in the linux kernel where a dump command
will be interrupted( I am not sure I understand what this really
means ) and the data sent back from the kernel is wrong or incomplete.

At this point in time I am not 100% certain what should be done, but
let's start noticing that this has happened so we can formulate a plan
or allow the end operator to know bad stuff is a foot at the circle K.

Signed-off-by: Donald Sharp <sharpd@nvidia.com>

diff --git a/zebra/kernel_netlink.c b/zebra/kernel_netlink.c
index 0dd76e3253a24092f43a0fef7a9b04f3b3863523..35f3274c6572be4c92b73c84f9e37510d5ec6ec7 100644 (file)
--- a/zebra/kernel_netlink.c
+++ b/zebra/kernel_netlink.c
@@ -1016,6 +1016,18 @@ int netlink_parse_info(int (*filter)(struct nlmsghdr *, ns_id_t, int),
                                        return err;
                        }
 
+                       /*
+                        * What is the right thing to do?  The kernel
+                        * is telling us that the dump request was interrupted
+                        * and we more than likely are out of luck and have
+                        * missed data from the kernel.  At this point in time
+                        * lets just note that this is happening.
+                        */
+                       if (h->nlmsg_flags & NLM_F_DUMP_INTR)
+                               flog_err(
+                                       EC_ZEBRA_NETLINK_BAD_SEQUENCE,
+                                       "netlink recvmsg: The Dump request was interrupted");
+
                        /* OK we got netlink message. */
                        if (IS_ZEBRA_DEBUG_KERNEL)
                                zlog_debug(