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authorNeale Ranns <nranns@cisco.com>2018-12-06 13:46:49 +0000
committerDamjan Marion <dmarion@me.com>2018-12-07 15:09:37 +0000
commit521a8d7df423a0b5aaf259d49ca9230705bc25ee (patch)
tree12559229002f31b289adb15460b967a3d10900f3 /src/vnet/adj/adj.h
parentab86f86e7c29393fa1da81b5f86296bd5fcb7420 (diff)
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 <nranns@cisco.com>
Diffstat (limited to 'src/vnet/adj/adj.h')
-rw-r--r--src/vnet/adj/adj.h63
1 files changed, 58 insertions, 5 deletions
diff --git a/src/vnet/adj/adj.h b/src/vnet/adj/adj.h
index 18a2e1ddbbb..fb3dc368db0 100644
--- a/src/vnet/adj/adj.h
+++ b/src/vnet/adj/adj.h
@@ -157,14 +157,12 @@ typedef void (*adj_midchain_fixup_t) (vlib_main_t * vm,
/**
* @brief Flags on an IP adjacency
*/
-typedef enum ip_adjacency_flags_t_
+typedef enum adj_attr_t_
{
- ADJ_FLAG_NONE = 0,
-
/**
* Currently a sync walk is active. Used to prevent re-entrant walking
*/
- ADJ_FLAG_SYNC_WALK_ACTIVE = (1 << 0),
+ ADJ_ATTR_SYNC_WALK_ACTIVE = 0,
/**
* Packets TX through the midchain do not increment the interface
@@ -173,10 +171,48 @@ typedef enum ip_adjacency_flags_t_
* the packet will have traversed the interface's TX node, and hence have
* been counted, before it traverses ths midchain
*/
- ADJ_FLAG_MIDCHAIN_NO_COUNT = (1 << 1),
+ ADJ_ATTR_MIDCHAIN_NO_COUNT,
+ /**
+ * When stacking midchains on a fib-entry extract the choice from the
+ * load-balance returned based on an IP hash of the adj's rewrite
+ */
+ ADJ_ATTR_MIDCHAIN_IP_STACK,
+ /**
+ * If the midchain were to stack on its FIB entry a loop would form.
+ */
+ ADJ_ATTR_MIDCHAIN_LOOPED,
+} adj_attr_t;
+
+#define ADJ_ATTR_NAMES { \
+ [ADJ_ATTR_SYNC_WALK_ACTIVE] = "walk-active", \
+ [ADJ_ATTR_MIDCHAIN_NO_COUNT] = "midchain-no-count", \
+ [ADJ_ATTR_MIDCHAIN_IP_STACK] = "midchain-ip-stack", \
+ [ADJ_ATTR_MIDCHAIN_LOOPED] = "midchain-looped", \
+}
+
+#define FOR_EACH_ADJ_ATTR(_attr) \
+ for (_attr = ADJ_ATTR_SYNC_WALK_ACTIVE; \
+ _attr <= ADJ_ATTR_MIDCHAIN_LOOPED; \
+ _attr++)
+
+/**
+ * @brief Flags on an IP adjacency
+ */
+typedef enum adj_flags_t_
+{
+ ADJ_FLAG_NONE = 0,
+ ADJ_FLAG_SYNC_WALK_ACTIVE = (1 << ADJ_ATTR_SYNC_WALK_ACTIVE),
+ ADJ_FLAG_MIDCHAIN_NO_COUNT = (1 << ADJ_ATTR_MIDCHAIN_NO_COUNT),
+ ADJ_FLAG_MIDCHAIN_IP_STACK = (1 << ADJ_ATTR_MIDCHAIN_IP_STACK),
+ ADJ_FLAG_MIDCHAIN_LOOPED = (1 << ADJ_ATTR_MIDCHAIN_LOOPED),
} __attribute__ ((packed)) adj_flags_t;
/**
+ * @brief Format adjacency flags
+ */
+extern u8* format_adj_flags(u8 * s, va_list * args);
+
+/**
* @brief IP unicast adjacency.
* @note cache aligned.
*
@@ -257,6 +293,11 @@ typedef struct ip_adjacency_t_
* Fixup data passed back to the client in the fixup function
*/
const void *fixup_data;
+ /**
+ * the FIB entry this midchain resolves through. required for recursive
+ * loop detection.
+ */
+ fib_node_index_t fei;
} midchain;
/**
* IP_LOOKUP_NEXT_GLEAN
@@ -355,6 +396,18 @@ extern const u8* adj_get_rewrite (adj_index_t ai);
extern void adj_feature_update (u32 sw_if_index, u8 arc_index, u8 is_enable);
/**
+ * @brief descend the FIB graph looking for loops
+ *
+ * @param ai
+ * The adj index to traverse
+ *
+ * @param entry_indicies)
+ * A pointer to a vector of FIB entries already visited.
+ */
+extern int adj_recursive_loop_detect (adj_index_t ai,
+ fib_node_index_t **entry_indicies);
+
+/**
* @brief
* The global adjacnecy pool. Exposed for fast/inline data-plane access
*/