From 521a8d7df423a0b5aaf259d49ca9230705bc25ee Mon Sep 17 00:00:00 2001 From: Neale Ranns Date: Thu, 6 Dec 2018 13:46:49 +0000 Subject: FIB recusrion loop checks traverse midchain adjacencies if a tunnel's destination address is reachable through the tunnel (see example config belwo) then search for and detect a recursion loop and don't stack the adjacency. Otherwise this results in a nasty surprise. DBGvpp# loop cre DBGvpp# set int state loop0 up DBGvpp# set int ip addr loop0 10.0.0.1/24 DBGvpp# create gre tunnel src 10.0.0.1 dst 1.1.1.1 DBGvpp# set int state gre0 up DBGvpp# set int unnum gre0 use loop0 DBGvpp# ip route 1.1.1.1/32 via gre0 DBGvpp# sh ip fib 1.1.1.1 ipv4-VRF:0, fib_index:0, flow hash:[src dst sport dport proto ] locks:[src:plugin-hi:2, src:default-route:1, ] 1.1.1.1/32 fib:0 index:11 locks:4 <<< this is entry #11 src:CLI refs:1 entry-flags:attached, src-flags:added,contributing,active, path-list:[14] locks:2 flags:shared,looped, uPRF-list:12 len:1 itfs:[2, ] path:[14] pl-index:14 ip4 weight=1 pref=0 attached-nexthop: oper-flags:recursive-loop,resolved, cfg-flags:attached, 1.1.1.1 gre0 (p2p) [@0]: ipv4 via 0.0.0.0 gre0: mtu:9000 4500000000000000fe2fb0cc0a0000010101010100000800 stacked-on entry:11: <<<< and the midchain forwards via entry #11 [@2]: dpo-drop ip4 src:recursive-resolution refs:1 src-flags:added, cover:-1 forwarding: unicast-ip4-chain [@0]: dpo-load-balance: [proto:ip4 index:13 buckets:1 uRPF:12 to:[0:0]] [0] [@6]: ipv4 via 0.0.0.0 gre0: mtu:9000 4500000000000000fe2fb0cc0a0000010101010100000800 stacked-on entry:11: [@2]: dpo-drop ip4 DBGvpp# sh adj 1 [@1] ipv4 via 0.0.0.0 gre0: mtu:9000 4500000000000000fe2fb0cc0a0000010101010100000800 stacked-on entry:11: [@2]: dpo-drop ip4 flags:midchain-ip-stack midchain-looped <<<<< this is a loop counts:[0:0] locks:4 delegates: children: {path:14} Change-Id: I39b82bd1ea439be4611c88b130d40289fa0c1b59 Signed-off-by: Neale Ranns --- src/vnet/lisp-gpe/lisp_gpe_adjacency.c | 54 +++++++--------------------------- 1 file changed, 10 insertions(+), 44 deletions(-) (limited to 'src/vnet/lisp-gpe') diff --git a/src/vnet/lisp-gpe/lisp_gpe_adjacency.c b/src/vnet/lisp-gpe/lisp_gpe_adjacency.c index 6f85dc4a761..7361e8eb0d6 100644 --- a/src/vnet/lisp-gpe/lisp_gpe_adjacency.c +++ b/src/vnet/lisp-gpe/lisp_gpe_adjacency.c @@ -131,48 +131,13 @@ static void lisp_gpe_adj_stack_one (lisp_gpe_adjacency_t * ladj, adj_index_t ai) { const lisp_gpe_tunnel_t *lgt; - dpo_id_t tmp = DPO_INVALID; lgt = lisp_gpe_tunnel_get (ladj->tunnel_index); - fib_entry_contribute_forwarding (lgt->fib_entry_index, - lisp_gpe_adj_get_fib_chain_type (ladj), - &tmp); - if (DPO_LOAD_BALANCE == tmp.dpoi_type) - { - /* - * post LISP rewrite we will load-balance. However, the LISP encap - * is always the same for this adjacency/tunnel and hence the IP/UDP src,dst - * hash is always the same result too. So we do that hash now and - * stack on the choice. - * If the choice is an incomplete adj then we will need a poke when - * it becomes complete. This happens since the adj update walk propagates - * as far a recursive paths. - */ - const dpo_id_t *choice; - load_balance_t *lb; - int hash; - - lb = load_balance_get (tmp.dpoi_index); - - if (IP4 == ip_addr_version (&ladj->remote_rloc)) - { - hash = ip4_compute_flow_hash ((ip4_header_t *) adj_get_rewrite (ai), - lb->lb_hash_config); - } - else - { - hash = ip6_compute_flow_hash ((ip6_header_t *) adj_get_rewrite (ai), - lb->lb_hash_config); - } - - choice = - load_balance_get_bucket_i (lb, hash & lb->lb_n_buckets_minus_1); - dpo_copy (&tmp, choice); - } - - adj_nbr_midchain_stack (ai, &tmp); - dpo_reset (&tmp); + adj_nbr_midchain_stack_on_fib_entry (ai, + lgt->fib_entry_index, + lisp_gpe_adj_get_fib_chain_type + (ladj)); } /** @@ -332,6 +297,7 @@ lisp_gpe_update_adjacency (vnet_main_t * vnm, u32 sw_if_index, adj_index_t ai) ip_adjacency_t *adj; ip_address_t rloc; vnet_link_t linkt; + adj_flags_t af; index_t lai; adj = adj_get (ai); @@ -347,12 +313,12 @@ lisp_gpe_update_adjacency (vnet_main_t * vnm, u32 sw_if_index, adj_index_t ai) ladj = pool_elt_at_index (lisp_adj_pool, lai); lgt = lisp_gpe_tunnel_get (ladj->tunnel_index); linkt = adj_get_link_type (ai); + af = ADJ_FLAG_MIDCHAIN_IP_STACK; + if (VNET_LINK_ETHERNET == linkt) + af |= ADJ_FLAG_MIDCHAIN_NO_COUNT; + adj_nbr_midchain_update_rewrite - (ai, lisp_gpe_fixup, - NULL, - (VNET_LINK_ETHERNET == linkt ? - ADJ_FLAG_MIDCHAIN_NO_COUNT : - ADJ_FLAG_NONE), + (ai, lisp_gpe_fixup, NULL, af, lisp_gpe_tunnel_build_rewrite (lgt, ladj, lisp_gpe_adj_proto_from_vnet_link_type (linkt))); -- cgit 1.2.3-korg