zebra: Send correct default vrf tableid for MROUTE stats

So the linux kernel uses the RT_TABLE_MAIN for the table
id used for ip routing.  The multicast routing tables use
RT_TABLE_DEFAULT.  We changed the internal code of zebra_vrf
a few months back to use RT_TABLE_MAIN as the tableid to
use.  This caused the pim sg stats to stop working because
of the kernel bug where it uses a different table
for ip routing and ip multicast.

Put a bit of a special case in to do the right thing.

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

diff --git a/zebra/rt_netlink.c b/zebra/rt_netlink.c
index 999ad1bdecb7502ce80ac35fd1b382b88ba9864f..8f47d3bfbdcb8cb890b92f3afe5c77710a65a801 100644 (file)
--- a/zebra/rt_netlink.c
+++ b/zebra/rt_netlink.c
@@ -1667,6 +1667,7 @@ skip:
 
 int kernel_get_ipmr_sg_stats(struct zebra_vrf *zvrf, void *in)
 {
+       uint32_t actual_table;
        int suc = 0;
        struct mcast_route_data *mr = (struct mcast_route_data *)in;
        struct {
@@ -1693,7 +1694,23 @@ int kernel_get_ipmr_sg_stats(struct zebra_vrf *zvrf, void *in)
        addattr_l(&req.n, sizeof(req), RTA_OIF, &mroute->ifindex, 4);
        addattr_l(&req.n, sizeof(req), RTA_SRC, &mroute->sg.src.s_addr, 4);
        addattr_l(&req.n, sizeof(req), RTA_DST, &mroute->sg.grp.s_addr, 4);
-       addattr_l(&req.n, sizeof(req), RTA_TABLE, &zvrf->table_id, 4);
+       /*
+        * What?
+        *
+        * So during the namespace cleanup we started storing
+        * the zvrf table_id for the default table as RT_TABLE_MAIN
+        * which is what the normal routing table for ip routing is.
+        * This change caused this to break our lookups of sg data
+        * because prior to this change the zvrf->table_id was 0
+        * and when the pim multicast kernel code saw a 0,
+        * it was auto-translated to RT_TABLE_DEFAULT.  But since
+        * we are now passing in RT_TABLE_MAIN there is no auto-translation
+        * and the kernel goes screw you and the delicious cookies you
+        * are trying to give me.  So now we have this little hack.
+        */
+       actual_table = (zvrf->table_id == RT_TABLE_MAIN) ? RT_TABLE_DEFAULT :
+               zvrf->table_id;
+       addattr_l(&req.n, sizeof(req), RTA_TABLE, &actual_table, 4);
 
        suc = netlink_talk(netlink_route_change_read_multicast, &req.n,
                           &zns->netlink_cmd, zns, 0);