Use 2 sep hashing functions to account for collisions...

Safe enough

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1208897 13f79535-47bb-0310-9956-ffa450edef68

3 files changed, 26 insertions, 14 deletions

diff --git a/modules/proxy/mod_proxy.c b/modules/proxy/mod_proxy.c
index e63be0800a..35195f8cce 100644
--- a/modules/proxy/mod_proxy.c
+++ b/modules/proxy/mod_proxy.c
@@ -2428,9 +2428,11 @@ static void child_init(apr_pool_t *p, server_rec *s)
             PROXY_STRNCPY(conf->forward->s->name,     "proxy:forward");
             PROXY_STRNCPY(conf->forward->s->hostname, "*");
             PROXY_STRNCPY(conf->forward->s->scheme,   "*");
-            conf->forward->hash = conf->forward->s->hash =
+            conf->forward->hash.def = conf->forward->s->hash.def =
                 ap_proxy_hashfunc(conf->forward->s->name, PROXY_HASHFUNC_DEFAULT);
-             /* Do not disable worker in case of errors */
+             conf->forward->hash.fnv = conf->forward->s->hash.fnv =
+                ap_proxy_hashfunc(conf->forward->s->name, PROXY_HASHFUNC_FNV);
+            /* Do not disable worker in case of errors */
             conf->forward->s->status |= PROXY_WORKER_IGNORE_ERRORS;
             /* Disable address cache for generic forward worker */
             conf->forward->s->is_address_reusable = 0;
@@ -2441,8 +2443,10 @@ static void child_init(apr_pool_t *p, server_rec *s)
             PROXY_STRNCPY(reverse->s->name,     "proxy:reverse");
             PROXY_STRNCPY(reverse->s->hostname, "*");
             PROXY_STRNCPY(reverse->s->scheme,   "*");
-            reverse->hash = reverse->s->hash =
+            reverse->hash.def = reverse->s->hash.def =
                 ap_proxy_hashfunc(reverse->s->name, PROXY_HASHFUNC_DEFAULT);
+            reverse->hash.fnv = reverse->s->hash.fnv =
+                ap_proxy_hashfunc(reverse->s->name, PROXY_HASHFUNC_FNV);
             /* Do not disable worker in case of errors */
             reverse->s->status |= PROXY_WORKER_IGNORE_ERRORS;
             /* Disable address cache for generic reverse worker */
diff --git a/modules/proxy/mod_proxy.h b/modules/proxy/mod_proxy.h
index f91afca81f..04379e7362 100644
--- a/modules/proxy/mod_proxy.h
+++ b/modules/proxy/mod_proxy.h
@@ -320,6 +320,11 @@ do {                             \
 (w)->s->io_buffer_size_set   = (c)->io_buffer_size_set;    \
 } while (0)
 
+/* use 2 hashes */
+typedef struct {
+    unsigned int def;
+    unsigned int fnv;
+} proxy_hashes ;
 
 /* Runtime worker status informations. Shared in scoreboard */
 typedef struct {
@@ -338,7 +343,7 @@ typedef struct {
     int             hmax;       /* Hard maximum on the total number of connections */
     int             flush_wait; /* poll wait time in microseconds if flush_auto */
     int             index;      /* shm array index */
-    unsigned int    hash;       /* hash of worker name */
+    proxy_hashes    hash;       /* hash of worker name */
     unsigned int    status;     /* worker status bitfield */
     enum {
         flush_off,
@@ -381,7 +386,7 @@ typedef struct {
 
 /* Worker configuration */
 struct proxy_worker {
-    unsigned int    hash;       /* hash of worker name */
+    proxy_hashes    hash;       /* hash of worker name */
     unsigned int local_status;  /* status of per-process worker */
     proxy_conn_pool     *cp;    /* Connection pool to use */
     proxy_worker_shared   *s;   /* Shared data */
@@ -409,7 +414,7 @@ typedef struct {
     apr_time_t      wupdated;     /* timestamp of last change to workers list */
     int             max_attempts;     /* Number of attempts before failing */
     int             index;      /* shm array index */
-    unsigned int hash;
+    proxy_hashes hash;
     unsigned int    sticky_force:1;   /* Disable failover for sticky sessions */
     unsigned int    scolonsep:1;      /* true if ';' seps sticky session paths */
     unsigned int    max_attempts_set:1;
@@ -428,7 +433,7 @@ struct proxy_balancer {
     ap_slotmem_provider_t *storage;
     int growth;                   /* number of post-config workers can added */
     int max_workers;              /* maximum number of allowed workers */
-    unsigned int hash;
+    proxy_hashes hash;
     apr_time_t      wupdated;    /* timestamp of last change to workers list */
     proxy_balancer_method *lbmethod;
     apr_global_mutex_t  *gmutex; /* global lock for updating list of workers */
diff --git a/modules/proxy/proxy_util.c b/modules/proxy/proxy_util.c
index 2af6768d18..6d33930bca 100644
--- a/modules/proxy/proxy_util.c
+++ b/modules/proxy/proxy_util.c
@@ -1298,7 +1298,7 @@ PROXY_DECLARE(proxy_balancer *) ap_proxy_get_balancer(apr_pool_t *p,
     proxy_balancer *balancer;
     char *c, *uri = apr_pstrdup(p, url);
     int i;
-    unsigned int hash;
+    proxy_hashes hash;
 
     ap_str_tolower(uri);
     c = strchr(uri, ':');
@@ -1309,10 +1309,11 @@ PROXY_DECLARE(proxy_balancer *) ap_proxy_get_balancer(apr_pool_t *p,
     if ((c = strchr(c + 3, '/'))) {
         *c = '\0';
     }
-    hash = ap_proxy_hashfunc(uri, PROXY_HASHFUNC_DEFAULT);
+    hash.def = ap_proxy_hashfunc(uri, PROXY_HASHFUNC_DEFAULT);
+    hash.fnv = ap_proxy_hashfunc(uri, PROXY_HASHFUNC_FNV);
     balancer = (proxy_balancer *)conf->balancers->elts;
     for (i = 0; i < conf->balancers->nelts; i++) {
-        if (balancer->hash == hash) {
+        if (balancer->hash.def == hash.def && balancer->hash.fnv == hash.fnv) {
             if (!care || !balancer->s->inactive) {
                 return balancer;
             }
@@ -1401,7 +1402,8 @@ PROXY_DECLARE(char *) ap_proxy_define_balancer(apr_pool_t *p,
     if (PROXY_STRNCPY(bshared->sname, sname) != APR_SUCCESS) {
         return apr_psprintf(p, "balancer safe-name (%s) too long", sname);
     }
-    bshared->hash = ap_proxy_hashfunc(bshared->name, PROXY_HASHFUNC_DEFAULT);    
+    bshared->hash.def = ap_proxy_hashfunc(bshared->name, PROXY_HASHFUNC_DEFAULT);
+    bshared->hash.fnv = ap_proxy_hashfunc(bshared->name, PROXY_HASHFUNC_FNV);
     (*balancer)->hash = bshared->hash;
 
     /* Retrieve a UUID and store the nonce for the lifetime of
@@ -1835,7 +1837,8 @@ PROXY_DECLARE(char *) ap_proxy_define_worker(apr_pool_t *p,
     wshared->is_address_reusable = 1;
     wshared->lbfactor = 1;
     wshared->smax = -1;
-    wshared->hash = ap_proxy_hashfunc(wshared->name, PROXY_HASHFUNC_DEFAULT);
+    wshared->hash.def = ap_proxy_hashfunc(wshared->name, PROXY_HASHFUNC_DEFAULT);
+    wshared->hash.fnv = ap_proxy_hashfunc(wshared->name, PROXY_HASHFUNC_FNV);
     wshared->was_malloced = (do_malloc != 0);
 
     (*worker)->hash = wshared->hash;
@@ -2985,13 +2988,13 @@ PROXY_DECLARE(apr_status_t) ap_proxy_sync_balancer(proxy_balancer *b, server_rec
         /* account for possible "holes" in the slotmem
          * (eg: slots 0-2 are used, but 3 isn't, but 4-5 is)
          */
-        if (!shm->hash)
+        if (!shm->hash.def || !shm->hash.fnv)
             continue;
         found = 0;
         workers = (proxy_worker **)b->workers->elts;
         for (i = 0; i < b->workers->nelts; i++, workers++) {
             proxy_worker *worker = *workers;
-            if (worker->hash == shm->hash) {
+            if (worker->hash.def == shm->hash.def && worker->hash.fnv == shm->hash.fnv) {
                 found = 1;
                 break;
             }