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authorNeale Ranns <nranns@cisco.com>2017-05-25 12:38:58 -0700
committerDamjan Marion <dmarion.lists@gmail.com>2017-05-25 21:03:11 +0000
commit71275e3d1ed4b7a536b7ec8d13995743beccde6b (patch)
tree8d900abc4a7b4365a75c5c88b7cf556ea537fd0a /src/vnet/mpls/mpls_lookup.c
parent3d0723d3e085c8a69e1827e2e5607281b90576d7 (diff)
MPLS hash function improvements
Change-Id: I28e98f445c01493562b6196a4f5b532a51f178af Signed-off-by: Neale Ranns <nranns@cisco.com>
Diffstat (limited to 'src/vnet/mpls/mpls_lookup.c')
-rw-r--r--src/vnet/mpls/mpls_lookup.c68
1 files changed, 62 insertions, 6 deletions
diff --git a/src/vnet/mpls/mpls_lookup.c b/src/vnet/mpls/mpls_lookup.c
index 322e0db0733..42e5399c2da 100644
--- a/src/vnet/mpls/mpls_lookup.c
+++ b/src/vnet/mpls/mpls_lookup.c
@@ -65,14 +65,70 @@ mpls_compute_flow_hash (const mpls_unicast_header_t * hdr,
flow_hash_config_t flow_hash_config)
{
/*
- * improve this to include:
- * - all labels in the stack.
- * - recognise entropy labels.
- *
* We need to byte swap so we use the numerical value. i.e. an odd label
- * leads to an odd bucket. ass opposed to a label above and below value X.
+ * leads to an odd bucket. as opposed to a label above and below value X.
*/
- return (vnet_mpls_uc_get_label(clib_net_to_host_u32(hdr->label_exp_s_ttl)));
+ u8 next_label_is_entropy;
+ mpls_label_t ho_label;
+ u32 hash, value;
+
+ ho_label = clib_net_to_host_u32(hdr->label_exp_s_ttl);
+ hash = vnet_mpls_uc_get_label(ho_label);
+ next_label_is_entropy = 0;
+
+ while (MPLS_EOS != vnet_mpls_uc_get_s(ho_label))
+ {
+ hdr++;
+ ho_label = clib_net_to_host_u32(hdr->label_exp_s_ttl);
+ value = vnet_mpls_uc_get_label(ho_label);
+
+ if (1 == next_label_is_entropy)
+ {
+ /*
+ * The label is an entropy value, use it alone as the hash
+ */
+ return (ho_label);
+ }
+ if (MPLS_IETF_ENTROPY_LABEL == value)
+ {
+ /*
+ * we've met a label in the stack indicating that tha next
+ * label is an entropy value
+ */
+ next_label_is_entropy = 1;
+ }
+ else
+ {
+ /*
+ * XOR the label values in the stack together to
+ * build up the hash value
+ */
+ hash ^= value;
+ }
+ }
+
+ /*
+ * check the top nibble for v4 and v6
+ */
+ hdr++;
+
+ switch (((u8*)hdr)[0] >> 4)
+ {
+ case 4:
+ /* incorporate the v4 flow-hash */
+ hash ^= ip4_compute_flow_hash ((const ip4_header_t *)hdr,
+ IP_FLOW_HASH_DEFAULT);
+ break;
+ case 6:
+ /* incorporate the v6 flow-hash */
+ hash ^= ip6_compute_flow_hash ((const ip6_header_t *)hdr,
+ IP_FLOW_HASH_DEFAULT);
+ break;
+ default:
+ break;
+ }
+
+ return (hash);
}
static inline uword