Limit conn: use complex value in limit_conn_zone (ticket #121).

One intentional side effect of this change is that key is allowed only
in the first position.  Previously, it was possible to specify the key
variable at any position, but that was never documented, and is contrary
to nginx configuration practice for positional parameters.

1 files changed, 54 insertions, 67 deletions

diff --git a/src/http/modules/ngx_http_limit_conn_module.c b/src/http/modules/ngx_http_limit_conn_module.c
index bc03d6242..dff158a4c 100644
--- a/src/http/modules/ngx_http_limit_conn_module.c
+++ b/src/http/modules/ngx_http_limit_conn_module.c
@@ -25,9 +25,8 @@ typedef struct {
 
 
 typedef struct {
-    ngx_rbtree_t       *rbtree;
-    ngx_int_t           index;
-    ngx_str_t           var;
+    ngx_rbtree_t              *rbtree;
+    ngx_http_complex_value_t   key;
 } ngx_http_limit_conn_ctx_t;
 
 
@@ -45,7 +44,7 @@ typedef struct {
 
 
 static ngx_rbtree_node_t *ngx_http_limit_conn_lookup(ngx_rbtree_t *rbtree,
-    ngx_http_variable_value_t *vv, uint32_t hash);
+    ngx_str_t *key, uint32_t hash);
 static void ngx_http_limit_conn_cleanup(void *data);
 static ngx_inline void ngx_http_limit_conn_cleanup_all(ngx_pool_t *pool);
 
@@ -141,13 +140,13 @@ ngx_module_t  ngx_http_limit_conn_module = {
 static ngx_int_t
 ngx_http_limit_conn_handler(ngx_http_request_t *r)
 {
-    size_t                          len, n;
+    size_t                          n;
     uint32_t                        hash;
+    ngx_str_t                       key;
     ngx_uint_t                      i;
     ngx_slab_pool_t                *shpool;
     ngx_rbtree_node_t              *node;
     ngx_pool_cleanup_t             *cln;
-    ngx_http_variable_value_t      *vv;
     ngx_http_limit_conn_ctx_t      *ctx;
     ngx_http_limit_conn_node_t     *lc;
     ngx_http_limit_conn_conf_t     *lccf;
@@ -164,41 +163,37 @@ ngx_http_limit_conn_handler(ngx_http_request_t *r)
     for (i = 0; i < lccf->limits.nelts; i++) {
         ctx = limits[i].shm_zone->data;
 
-        vv = ngx_http_get_indexed_variable(r, ctx->index);
-
-        if (vv == NULL || vv->not_found) {
-            continue;
+        if (ngx_http_complex_value(r, &ctx->key, &key) != NGX_OK) {
+            return NGX_HTTP_INTERNAL_SERVER_ERROR;
         }
 
-        len = vv->len;
-
-        if (len == 0) {
+        if (key.len == 0) {
             continue;
         }
 
-        if (len > 255) {
+        if (key.len > 255) {
             ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
-                          "the value of the \"%V\" variable "
-                          "is more than 255 bytes: \"%v\"",
-                          &ctx->var, vv);
+                          "the value of the \"%V\" key "
+                          "is more than 255 bytes: \"%V\"",
+                          &ctx->key.value, &key);
             continue;
         }
 
         r->main->limit_conn_set = 1;
 
-        hash = ngx_crc32_short(vv->data, len);
+        hash = ngx_crc32_short(key.data, key.len);
 
         shpool = (ngx_slab_pool_t *) limits[i].shm_zone->shm.addr;
 
         ngx_shmtx_lock(&shpool->mutex);
 
-        node = ngx_http_limit_conn_lookup(ctx->rbtree, vv, hash);
+        node = ngx_http_limit_conn_lookup(ctx->rbtree, &key, hash);
 
         if (node == NULL) {
 
             n = offsetof(ngx_rbtree_node_t, color)
                 + offsetof(ngx_http_limit_conn_node_t, data)
-                + len;
+                + key.len;
 
             node = ngx_slab_alloc_locked(shpool, n);
 
@@ -211,9 +206,9 @@ ngx_http_limit_conn_handler(ngx_http_request_t *r)
             lc = (ngx_http_limit_conn_node_t *) &node->color;
 
             node->key = hash;
-            lc->len = (u_char) len;
+            lc->len = (u_char) key.len;
             lc->conn = 1;
-            ngx_memcpy(lc->data, vv->data, len);
+            ngx_memcpy(lc->data, key.data, key.len);
 
             ngx_rbtree_insert(ctx->rbtree, node);
 
@@ -300,8 +295,7 @@ ngx_http_limit_conn_rbtree_insert_value(ngx_rbtree_node_t *temp,
 
 
 static ngx_rbtree_node_t *
-ngx_http_limit_conn_lookup(ngx_rbtree_t *rbtree, ngx_http_variable_value_t *vv,
-    uint32_t hash)
+ngx_http_limit_conn_lookup(ngx_rbtree_t *rbtree, ngx_str_t *key, uint32_t hash)
 {
     ngx_int_t                    rc;
     ngx_rbtree_node_t           *node, *sentinel;
@@ -326,8 +320,8 @@ ngx_http_limit_conn_lookup(ngx_rbtree_t *rbtree, ngx_http_variable_value_t *vv,
 
         lcn = (ngx_http_limit_conn_node_t *) &node->color;
 
-        rc = ngx_memn2cmp(vv->data, lcn->data,
-                          (size_t) vv->len, (size_t) lcn->len);
+        rc = ngx_memn2cmp(key->data, lcn->data, key->len, (size_t) lcn->len);
+
         if (rc == 0) {
             return node;
         }
@@ -399,11 +393,16 @@ ngx_http_limit_conn_init_zone(ngx_shm_zone_t *shm_zone, void *data)
     ctx = shm_zone->data;
 
     if (octx) {
-        if (ngx_strcmp(ctx->var.data, octx->var.data) != 0) {
+        if (ctx->key.value.len != octx->key.value.len
+            || ngx_strncmp(ctx->key.value.data, octx->key.value.data,
+                           ctx->key.value.len)
+               != 0)
+        {
             ngx_log_error(NGX_LOG_EMERG, shm_zone->shm.log, 0,
-                          "limit_conn_zone \"%V\" uses the \"%V\" variable "
-                          "while previously it used the \"%V\" variable",
-                          &shm_zone->shm.name, &ctx->var, &octx->var);
+                          "limit_conn_zone \"%V\" uses the \"%V\" key "
+                          "while previously it used the \"%V\" key",
+                          &shm_zone->shm.name, &ctx->key.value,
+                          &octx->key.value);
             return NGX_ERROR;
         }
 
@@ -493,20 +492,35 @@ ngx_http_limit_conn_merge_conf(ngx_conf_t *cf, void *parent, void *child)
 static char *
 ngx_http_limit_conn_zone(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
 {
-    u_char                     *p;
-    ssize_t                     size;
-    ngx_str_t                  *value, name, s;
-    ngx_uint_t                  i;
-    ngx_shm_zone_t             *shm_zone;
-    ngx_http_limit_conn_ctx_t  *ctx;
+    u_char                            *p;
+    ssize_t                            size;
+    ngx_str_t                         *value, name, s;
+    ngx_uint_t                         i;
+    ngx_shm_zone_t                    *shm_zone;
+    ngx_http_limit_conn_ctx_t         *ctx;
+    ngx_http_compile_complex_value_t   ccv;
 
     value = cf->args->elts;
 
-    ctx = NULL;
+    ctx = ngx_pcalloc(cf->pool, sizeof(ngx_http_limit_conn_ctx_t));
+    if (ctx == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t));
+
+    ccv.cf = cf;
+    ccv.value = &value[1];
+    ccv.complex_value = &ctx->key;
+
+    if (ngx_http_compile_complex_value(&ccv) != NGX_OK) {
+        return NGX_CONF_ERROR;
+    }
+
     size = 0;
     name.len = 0;
 
-    for (i = 1; i < cf->args->nelts; i++) {
+    for (i = 2; i < cf->args->nelts; i++) {
 
         if (ngx_strncmp(value[i].data, "zone=", 5) == 0) {
 
@@ -542,26 +556,6 @@ ngx_http_limit_conn_zone(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
             continue;
         }
 
-        if (value[i].data[0] == '$') {
-
-            value[i].len--;
-            value[i].data++;
-
-            ctx = ngx_pcalloc(cf->pool, sizeof(ngx_http_limit_conn_ctx_t));
-            if (ctx == NULL) {
-                return NGX_CONF_ERROR;
-            }
-
-            ctx->index = ngx_http_get_variable_index(cf, &value[i]);
-            if (ctx->index == NGX_ERROR) {
-                return NGX_CONF_ERROR;
-            }
-
-            ctx->var = value[i];
-
-            continue;
-        }
-
         ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                            "invalid parameter \"%V\"", &value[i]);
         return NGX_CONF_ERROR;
@@ -574,13 +568,6 @@ ngx_http_limit_conn_zone(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
         return NGX_CONF_ERROR;
     }
 
-    if (ctx == NULL) {
-        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
-                           "no variable is defined for %V \"%V\"",
-                           &cmd->name, &name);
-        return NGX_CONF_ERROR;
-    }
-
     shm_zone = ngx_shared_memory_add(cf, &name, size,
                                      &ngx_http_limit_conn_module);
     if (shm_zone == NULL) {
@@ -591,8 +578,8 @@ ngx_http_limit_conn_zone(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
         ctx = shm_zone->data;
 
         ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
-                           "%V \"%V\" is already bound to variable \"%V\"",
-                           &cmd->name, &name, &ctx->var);
+                           "%V \"%V\" is already bound to key \"%V\"",
+                           &cmd->name, &name, &ctx->key.value);
         return NGX_CONF_ERROR;
     }