[Openvpn-devel] [M] Change in openvpn[master]: Change hash iv to a dynamically allocated ctx

Attention is currently required from: flichtenheld.

Hello flichtenheld, 

I'd like you to reexamine a change. Please visit

    http://gerrit.openvpn.net/c/openvpn/+/1571?usp=email

to look at the new patch set (#11).

The following approvals got outdated and were removed:
Code-Review-1 by flichtenheld


Change subject: Change hash iv to a dynamically allocated ctx
......................................................................

Change hash iv to a dynamically allocated ctx

While for our own hash function, always using an uint32_t works well, it does
not work very well if we move to another hash function. Move the context of
a hardcoded uint32_t iv to a void pointer to a real ctx.

Change-Id: If47c7d920b2fa4047b7db03fcde821899839324d
Signed-off-by: Arne Schwabe <[email protected]>
---
M src/openvpn/list.c
M src/openvpn/list.h
M src/openvpn/mroute.c
M src/openvpn/mroute.h
M src/openvpn/multi.c
M tests/unit_tests/openvpn/test_misc.c
6 files changed, 48 insertions(+), 23 deletions(-)


  git pull ssh://gerrit.openvpn.net:29418/openvpn refs/changes/71/1571/11

diff --git a/src/openvpn/list.c b/src/openvpn/list.c
index c07e764..83b42b6 100644
--- a/src/openvpn/list.c
+++ b/src/openvpn/list.c
@@ -29,13 +29,16 @@
 
 #include "integer.h"
 #include "list.h"
+
+#include "crypto.h"
 #include "misc.h"
 
 #include "memdbg.h"
 
 struct hash *
-hash_init(const uint32_t n_buckets, const uint32_t iv,
-          uint64_t (*hash_function)(const void *key, uint32_t iv),
+hash_init(const uint32_t n_buckets, void *ctx,
+          void (*free_hash_ctx)(void *ctx),
+          uint64_t (*hash_function)(const void *key, void *ctx),
           bool (*compare_function)(const void *key1, const void *key2))
 {
     struct hash *h;
@@ -46,7 +49,8 @@
     h->mask = h->n_buckets - 1;
     h->hash_function = hash_function;
     h->compare_function = compare_function;
-    h->iv = iv;
+    h->free_ctx = free_hash_ctx;
+    h->ctx = ctx;
     ALLOC_ARRAY(h->buckets, struct hash_bucket, h->n_buckets);
     for (uint32_t i = 0; i < h->n_buckets; ++i)
     {
@@ -71,6 +75,7 @@
             he = next;
         }
     }
+    hash->free_ctx(hash->ctx);
     free(hash->buckets);
     free(hash);
 }
@@ -412,6 +417,18 @@
         c ^= (b >> 15); \
     }
 
+/**
+ * Creates a context that allows to use the hash function (hash_func) and
+ * @return a new context for the use with hash_func
+ */
+void *
+hash_func_new_ctx(void)
+{
+    uint32_t *ctx = malloc(sizeof(uint32_t));
+    *ctx = (uint32_t)get_random();
+    return ctx;
+}
+
 uint64_t
 hash_func(const uint8_t *k, uint32_t length, uint32_t initval)
 {
diff --git a/src/openvpn/list.h b/src/openvpn/list.h
index 06377c6..5835b87 100644
--- a/src/openvpn/list.h
+++ b/src/openvpn/list.h
@@ -54,14 +54,16 @@
     uint32_t n_buckets;
     uint32_t n_elements;
     uint32_t mask;
-    uint32_t iv;
-    uint64_t (*hash_function)(const void *key, uint32_t iv);
+    void *ctx;
+    uint64_t (*hash_function)(const void *key, void *ctx);
     bool (*compare_function)(const void *key1, const void *key2); /* return true if equal */
+    void (*free_ctx)(void *ctx);
     struct hash_bucket *buckets;
 };
 
-struct hash *hash_init(const uint32_t n_buckets, const uint32_t iv,
-                       uint64_t (*hash_function)(const void *key, uint32_t iv),
+struct hash *hash_init(const uint32_t n_buckets, void *ctx,
+                       void (*free_hash_ctx)(void *ctx),
+                       uint64_t (*hash_function)(const void *key, void *ctx),
                        bool (*compare_function)(const void *key1, const void *key2));
 
 void hash_free(struct hash *hash);
@@ -100,10 +102,12 @@
 
 uint64_t hash_func(const uint8_t *k, uint32_t length, uint32_t initval);
 
+void *hash_func_new_ctx(void);
+
 static inline uint64_t
 hash_value(const struct hash *hash, const void *key)
 {
-    return (*hash->hash_function)(key, hash->iv);
+    return (*hash->hash_function)(key, hash->ctx);
 }
 
 static inline uint32_t
diff --git a/src/openvpn/mroute.c b/src/openvpn/mroute.c
index 78c689e..89b3ecc 100644
--- a/src/openvpn/mroute.c
+++ b/src/openvpn/mroute.c
@@ -355,10 +355,11 @@
  * and the actual address.
  */
 uint64_t
-mroute_addr_hash_function(const void *key, uint32_t iv)
+mroute_addr_hash_function(const void *key, void *ctx)
 {
+    uint32_t *iv = ctx;
     return hash_func(mroute_addr_hash_ptr((const struct mroute_addr *)key),
-                     mroute_addr_hash_len((const struct mroute_addr *)key), iv);
+                     mroute_addr_hash_len((const struct mroute_addr *)key), *iv);
 }
 
 bool
diff --git a/src/openvpn/mroute.h b/src/openvpn/mroute.h
index 2f5d019..51b62d2 100644
--- a/src/openvpn/mroute.h
+++ b/src/openvpn/mroute.h
@@ -144,7 +144,7 @@
 
 bool mroute_learnable_address(const struct mroute_addr *addr, struct gc_arena *gc);
 
-uint64_t mroute_addr_hash_function(const void *key, uint32_t iv);
+uint64_t mroute_addr_hash_function(const void *key, void *ctx);
 
 bool mroute_addr_compare_function(const void *key1, const void *key2);
 
diff --git a/src/openvpn/multi.c b/src/openvpn/multi.c
index fe2badb..002293b 100644
--- a/src/openvpn/multi.c
+++ b/src/openvpn/multi.c
@@ -229,7 +229,7 @@
 #ifdef ENABLE_MANAGEMENT
 
 static uint64_t
-cid_hash_function(const void *key, uint32_t iv)
+cid_hash_function(const void *key, void *ctx)
 {
     const unsigned long *k = (const unsigned long *)key;
     return (uint64_t)*k;
@@ -250,7 +250,7 @@
 /*
  * inotify watcher descriptors are used as hash value
  */
-int_hash_function(const void *key, uint32_t iv)
+int_hash_function(const void *key, void *ctx)
 {
     return (uintptr_t)key;
 }
@@ -290,27 +290,30 @@
      * to determine which client sent an incoming packet
      * which is seen on the TCP/UDP socket.
      */
-    m->hash = hash_init(t->options.real_hash_size, (uint32_t)get_random(),
+    m->hash = hash_init(t->options.real_hash_size, hash_func_new_ctx(), free,
                         mroute_addr_hash_function, mroute_addr_compare_function);
 
     /*
      * Virtual address hash table.  Used to determine
      * which client to route a packet to.
      */
-    m->vhash = hash_init(t->options.virtual_hash_size, (uint32_t)get_random(),
+    m->vhash = hash_init(t->options.virtual_hash_size, hash_func_new_ctx(), free,
                          mroute_addr_hash_function, mroute_addr_compare_function);
 
 #ifdef ENABLE_MANAGEMENT
-    m->cid_hash = hash_init(t->options.real_hash_size, 0, cid_hash_function, cid_compare_function);
+    m->cid_hash = hash_init(t->options.real_hash_size, NULL, free, cid_hash_function, cid_compare_function);
 #endif
 
 #ifdef ENABLE_ASYNC_PUSH
     /*
      * Mapping between inotify watch descriptors and
      * multi_instances.
+     *
+     * Note we use a custom hash function here so we use dummy
+     * value and function for the context parameters.
      */
-    m->inotify_watchers = hash_init(t->options.real_hash_size, (uint32_t)get_random(),
-                                    int_hash_function, int_compare_function);
+    m->inotify_watchers =
+        hash_init(t->options.real_hash_size, NULL, free, int_hash_function, int_compare_function);
 #endif
 
     /*
diff --git a/tests/unit_tests/openvpn/test_misc.c b/tests/unit_tests/openvpn/test_misc.c
index fc9840a..7f22ad2 100644
--- a/tests/unit_tests/openvpn/test_misc.c
+++ b/tests/unit_tests/openvpn/test_misc.c
@@ -128,11 +128,12 @@
 
 
 static uint64_t
-word_hash_function(const void *key, uint32_t iv)
+word_hash_function(const void *key, void *ctx)
 {
+    uint32_t *iv = (uint32_t *)ctx;
     const char *str = (const char *)key;
     const uint32_t len = (uint32_t)strlen(str);
-    return hash_func((const uint8_t *)str, len, iv);
+    return hash_func((const uint8_t *)str, len, *iv);
 }
 
 static bool
@@ -174,10 +175,9 @@
      * Test the hash code by implementing a simple
      * word frequency algorithm.
      */
-
     struct gc_arena gc = gc_new();
-    struct hash *hash = hash_init(10000, get_random(), word_hash_function, word_compare_function);
-    struct hash *nhash = hash_init(256, get_random(), word_hash_function, word_compare_function);
+    struct hash *hash = hash_init(10000, hash_func_new_ctx(), free, word_hash_function, word_compare_function);
+    struct hash *nhash = hash_init(256, hash_func_new_ctx(), free, word_hash_function, word_compare_function);
 
     printf("hash_init n_buckets=%u mask=0x%08x\n", hash->n_buckets, hash->mask);
 

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Gerrit-MessageType: newpatchset
Gerrit-Project: openvpn
Gerrit-Branch: master
Gerrit-Change-Id: If47c7d920b2fa4047b7db03fcde821899839324d
Gerrit-Change-Number: 1571
Gerrit-PatchSet: 11
Gerrit-Owner: plaisthos <[email protected]>
Gerrit-Reviewer: flichtenheld <[email protected]>
Gerrit-CC: openvpn-devel <[email protected]>
Gerrit-Attention: flichtenheld <[email protected]>

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