MEDIUM: backend: add support for the wt6 hash
This function was designed for haproxy while testing other functions
in the past. Initially it was not planned to be used given the not
very interesting numbers it showed on real URL data : it is not as
smooth as the other ones. But later tests showed that the other ones
are extremely sensible to the server count and the type of input data,
especially DJB2 which must not be used on numeric input. So in fact
this function is still a generally average performer and it can make
sense to merge it in the end, as it can provide an alternative to
sdbm+avalanche or djb2+avalanche for consistent hashing or when hashing
on numeric data such as a source IP address or a visitor identifier in
a URL parameter.
diff --git a/include/types/backend.h b/include/types/backend.h
index 57d17bd..6325be2 100644
--- a/include/types/backend.h
+++ b/include/types/backend.h
@@ -114,6 +114,7 @@
/* BE_LB_HFCN_* is the hash function, to be used with BE_LB_HASH_FUNC */
#define BE_LB_HFCN_SDBM 0x000000 /* sdbm hash */
#define BE_LB_HFCN_DJB2 0x400000 /* djb2 hash */
+#define BE_LB_HFCN_WT6 0x800000 /* wt6 hash */
#define BE_LB_HASH_FUNC 0xC00000 /* get/clear hash function */