Re: ospfd siphash

[Ted Unangst]

On Fri, Dec 12, 2014 at 13:55, Ted Unangst wrote:
> This is pretty easy.

And essentially the same diff for ospf6d.

Index: lsupdate.c
===================================================================
RCS file: /cvs/src/usr.sbin/ospf6d/lsupdate.c,v
retrieving revision 1.10
diff -u -p -r1.10 lsupdate.c
--- lsupdate.c  25 Mar 2013 14:29:35 -0000      1.10
+++ lsupdate.c  12 Dec 2014 19:59:58 -0000
@@ -18,7 +18,6 @@
  */
 
 #include <sys/types.h>
-#include <sys/hash.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <netinet/ip6.h>
@@ -27,6 +26,7 @@
 
 #include <stdlib.h>
 #include <string.h>
+#include <siphash.h>
 
 #include "ospf6.h"
 #include "ospf6d.h"
@@ -542,6 +542,8 @@ struct lsa_cache {
        u_int32_t                hashmask;
 } lsacache;
 
+SIPHASH_KEY lsacachekey;
+
 struct lsa_ref         *lsa_cache_look(struct lsa_hdr *);
 
 void
@@ -557,10 +559,17 @@ lsa_cache_init(u_int32_t hashsize)
 
        for (i = 0; i < hs; i++)
                LIST_INIT(&lsacache.hashtbl[i]);
+       arc4random_buf(&lsacachekey, sizeof(lsacachekey));
 
        lsacache.hashmask = hs - 1;
 }
 
+uint32_t
+lsa_hash_hdr(const struct lsa_hdr *hdr)
+{
+       return SipHash24(&lsacachekey, hdr, sizeof(*hdr));
+}
+
 struct lsa_ref *
 lsa_cache_add(void *data, u_int16_t len)
 {
@@ -587,8 +596,7 @@ lsa_cache_add(void *data, u_int16_t len)
        ref->len = len;
        ref->refcnt = 1;
 
-       head = &lsacache.hashtbl[hash32_buf(&ref->hdr, sizeof(ref->hdr),
-           HASHINIT) & lsacache.hashmask];
+       head = &lsacache.hashtbl[lsa_hash_hdr(&ref->hdr) & lsacache.hashmask];
        LIST_INSERT_HEAD(head, ref, entry);
        return (ref);
 }
@@ -626,8 +634,7 @@ lsa_cache_look(struct lsa_hdr *lsa_hdr)
        struct lsa_cache_head   *head;
        struct lsa_ref          *ref;
 
-       head = &lsacache.hashtbl[hash32_buf(lsa_hdr, sizeof(*lsa_hdr),
-           HASHINIT) & lsacache.hashmask];
+       head = &lsacache.hashtbl[lsa_hash_hdr(lsa_hdr) & lsacache.hashmask];
 
        LIST_FOREACH(ref, head, entry) {
                if (memcmp(&ref->hdr, lsa_hdr, sizeof(*lsa_hdr)) == 0)