From: Willy Tarreau <w@1wt.eu>
Date: Sun, 6 Jun 2010 10:11:37 +0000 (+0200)
Subject: [MINOR] stick_table: add support for variable-sized data
X-Git-Tag: v1.5-dev8~569
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=393379c3e0a39aacc3d87065ae7cb7cbcc52cc7e;p=thirdparty%2Fhaproxy.git

[MINOR] stick_table: add support for variable-sized data

Right now we're only able to store a server ID in a sticky session.
The goal is to be able to store anything whose size is known at startup
time. For this, we store the extra data before the stksess pointer,
using a negative offset. It will then be easy to cumulate multiple
data provided they each have their own offset.
---

diff --git a/include/proto/stick_table.h b/include/proto/stick_table.h
index 1cc4624efd..ed44cc0c75 100644
--- a/include/proto/stick_table.h
+++ b/include/proto/stick_table.h
@@ -25,7 +25,7 @@
 #include <types/stick_table.h>
 
 struct stksess *stksess_new(struct stktable *t, struct stktable_key *key);
-void stksess_key(struct stktable *t, struct stksess *ts, struct stktable_key *key);
+void stksess_setkey(struct stktable *t, struct stksess *ts, struct stktable_key *key);
 void stksess_free(struct stktable *t, struct stksess *ts);
 
 int stktable_init(struct stktable *t);
diff --git a/include/types/stick_table.h b/include/types/stick_table.h
index b63b790e7a..bbb9d0d0f6 100644
--- a/include/types/stick_table.h
+++ b/include/types/stick_table.h
@@ -48,7 +48,11 @@ struct stktable_type {
 	size_t default_size;      /* default key size */
 };
 
-/* sticky session */
+/* Sticky session.
+ * Any additional data related to the stuck session is installed *before*
+ * stksess (with negative offsets). This allows us to run variable-sized
+ * keys and variable-sized data without making use of intermediate pointers.
+ */
 struct stksess {
 	int sid;                  /* id of server to use for this session */
 	unsigned int expire;      /* session expiration date */
@@ -70,6 +74,7 @@ struct stktable {
 	int nopurge;              /* if non-zero, don't purge sticky sessions when full */
 	int exp_next;             /* next expiration date (ticks) */
 	int expire;               /* time to live for sticky sessions (milliseconds) */
+	int data_size;            /* the size of the data that is prepended *before* stksess */
 };
 
 /*** The definitions below should probably be better placed in pattern.h ***/
diff --git a/src/session.c b/src/session.c
index ba8cec132e..137bbd330d 100644
--- a/src/session.c
+++ b/src/session.c
@@ -1032,7 +1032,7 @@ int process_store_rules(struct session *s, struct buffer *rep, int an_bit)
 				continue;
 
 			if (storereqidx != -1) {
-				stksess_key(s->store[storereqidx].table, s->store[storereqidx].ts, key);
+				stksess_setkey(s->store[storereqidx].table, s->store[storereqidx].ts, key);
 				s->store[storereqidx].flags = 1;
 			}
 			else if (s->store_count < (sizeof(s->store) / sizeof(s->store[0]))) {
diff --git a/src/stick_table.c b/src/stick_table.c
index bc75f67f8a..19cef35ecd 100644
--- a/src/stick_table.c
+++ b/src/stick_table.c
@@ -35,14 +35,14 @@
 void stksess_free(struct stktable *t, struct stksess *ts)
 {
 	t->current--;
-	pool_free2(t->pool, ts);
+	pool_free2(t->pool, (void *)ts - t->data_size);
 }
 
 /*
  * Initialize or update the key in the sticky session <ts> present in table <t>
  * from the value present in <key>.
  */
-void stksess_key(struct stktable *t, struct stksess *ts, struct stktable_key *key)
+void stksess_setkey(struct stktable *t, struct stksess *ts, struct stktable_key *key)
 {
 	if (t->type != STKTABLE_TYPE_STRING)
 		memcpy(ts->keys.key, key->key, t->key_size);
@@ -54,15 +54,15 @@ void stksess_key(struct stktable *t, struct stksess *ts, struct stktable_key *ke
 
 
 /*
- * Init sticky session <ts> of table <t> using <key>.
+ * Init sticky session <ts> of table <t>. The data parts are cleared and <ts>
+ * is returned.
  */
-struct stksess *stksess_init(struct stktable *t, struct stksess * ts, struct stktable_key *key)
+static struct stksess *stksess_init(struct stktable *t, struct stksess * ts)
 {
+	memset((void *)ts - t->data_size, 0, t->data_size);
+	ts->sid = 0;
 	ts->keys.node.leaf_p = NULL;
 	ts->exps.node.leaf_p = NULL;
-	ts->sid = 0;
-	stksess_key(t, ts, key);
-
 	return ts;
 }
 
@@ -138,10 +138,11 @@ struct stksess *stksess_new(struct stktable *t, struct stktable_key *key)
 			return NULL;
 	}
 
-	ts = pool_alloc2(t->pool);
+	ts = pool_alloc2(t->pool) + t->data_size;
 	if (ts) {
 		t->current++;
-		stksess_init(t, ts, key);
+		stksess_init(t, ts);
+		stksess_setkey(t, ts, key);
 	}
 
 	return ts;
@@ -281,7 +282,7 @@ int stktable_init(struct stktable *t)
 		memset(&t->keys, 0, sizeof(t->keys));
 		memset(&t->exps, 0, sizeof(t->exps));
 
-		t->pool = create_pool("sticktables", sizeof(struct stksess) + t->key_size, MEM_F_SHARED);
+		t->pool = create_pool("sticktables", sizeof(struct stksess) + t->data_size + t->key_size, MEM_F_SHARED);
 
 		t->exp_next = TICK_ETERNITY;
 		if ( t->expire ) {