X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=src%2Fvppinfra%2Fhash.h;h=de155e6ac1c537029472be8ca20f6a52e96ca129;hb=73710c7da2f8deaea83dbbbfce8737c9c6cd2949;hp=21986ea774c342dfdd2df0a6015510658a705114;hpb=0b061112f73fda45084671120411a6484d9c11d2;p=vpp.git

diff --git a/src/vppinfra/hash.h b/src/vppinfra/hash.h
index 21986ea774c..de155e6ac1c 100644
--- a/src/vppinfra/hash.h
+++ b/src/vppinfra/hash.h
@@ -77,6 +77,7 @@ typedef struct hash_header
 #define KEY_FUNC_POINTER_UWORD	(1)	/*< sum = *(uword *) key */
 #define KEY_FUNC_POINTER_U32	(2)	/*< sum = *(u32 *) key */
 #define KEY_FUNC_STRING         (3)	/*< sum = string_key_sum, etc. */
+#define KEY_FUNC_MEM		(4)	/*< sum = mem_key_sum */
 
   /* key comparison function */
   hash_key_equal_function_t *key_equal;
@@ -672,6 +673,20 @@ extern uword string_key_sum (hash_t * h, uword key);
 extern uword string_key_equal (hash_t * h, uword key1, uword key2);
 extern u8 *string_key_format_pair (u8 * s, va_list * args);
 
+/*
+ * Note: if you plan to put a hash into shared memory,
+ * the key sum and key equal functions MUST be set to magic constants!
+ * PIC means that whichever process sets up the hash won't have
+ * the actual key sum functions at the same place, leading to
+ * very hard-to-find bugs...
+ */
+
+#define hash_create_shmem(elts,key_bytes,value_bytes)           \
+  hash_create2((elts),(key_bytes),(value_bytes),                \
+               (hash_key_sum_function_t *) KEY_FUNC_MEM,        \
+               (hash_key_equal_function_t *)KEY_FUNC_MEM,       \
+               0, 0)
+
 #define hash_create_string(elts,value_bytes)                    \
   hash_create2((elts),0,(value_bytes),                          \
                (hash_key_sum_function_t *) KEY_FUNC_STRING,     \