bgpd-set-somark.patch

BGP: Set SO_MARK on connecting sockets to ensure lookup in right routing table

In the presence of a function such as management VRF/MRF, bgpd needs to be able
to specify that it intends to run in the dataplane and not the front panel.
To ensure this, we add a mark in the connecting socket so that the kernel
does the routing lookup in the right table. This assumes that an appropriate
ip rule has been configured (outside the scope of this package).

While we've forced the mark to be 254 for now, it maybe required to make it
configurable at a later time.

1 files changed, 19 insertions, 0 deletions

diff --git a/lib/sockunion.c b/lib/sockunion.c
index efd41362c..59c5ba5dd 100644
--- a/lib/sockunion.c
+++ b/lib/sockunion.c
@@ -496,6 +496,25 @@ sockopt_cork (int sock, int onoff)
 #endif
 }
 
+int sockopt_mark_default(int sock, int mark, struct zebra_privs_t *cap)
+{
+#ifdef SO_MARK
+  int ret;
+
+  if ( cap->change (ZPRIVS_RAISE) )
+    zlog_err ("routing_socket: Can't raise privileges");
+
+  ret = setsockopt(sock, SOL_SOCKET, SO_MARK, &mark, sizeof(mark));
+
+  if ( cap->change (ZPRIVS_LOWER) )
+    zlog_err ("routing_socket: Can't lower privileges");
+
+  return ret;
+#else
+  return 0;
+#endif
+}
+
 int
 sockopt_minttl (int family, int sock, int minttl)
 {