MINOR: backend: extract conn hash calculation from connect_server()

On connection reuse, a hash is first calculated. It is generated from
various connection parameters, to retrieve a matching connection.

Extract hash calculation from connect_server() into a new dedicated
function be_calculate_conn_hash(). The objective is to be able to
perform connection reuse for checks, without connect_server() invokation
which relies on a stream instance.

diff --git a/include/haproxy/backend.h b/include/haproxy/backend.h
index 93a4bee2b53190f336eec19bc53b70dd9eaa53d0..71c006391341084492b805c38d5f35715184a2ec 100644 (file)
--- a/include/haproxy/backend.h
+++ b/include/haproxy/backend.h
@@ -45,6 +45,12 @@ int assign_server_and_queue(struct stream *s);
 int alloc_bind_address(struct sockaddr_storage **ss,
                        struct server *srv, struct proxy *be,
                        struct stream *s);
+
+int64_t be_calculate_conn_hash(struct server *srv, struct stream *strm,
+                               struct session *sess,
+                               struct sockaddr_storage *src,
+                               struct sockaddr_storage *dst);
+
 int srv_redispatch_connect(struct stream *t);
 void back_try_conn_req(struct stream *s);
 void back_handle_st_req(struct stream *s);

diff --git a/src/backend.c b/src/backend.c
index e0ac22b319ca0202c7e6830b5e678cb5efa41bb7..6bed3d0823a362617db7a08d6c82db51789e4798 100644 (file)
--- a/src/backend.c
+++ b/src/backend.c
@@ -1531,6 +1531,96 @@ kill_random_idle_conn(struct server *srv)
        return 0;
 }
 
+/* Calculate hash to select a matching connection for reuse. Here is the list
+ * of input parameters :
+ * - <srv> is the server instance. Can be NULL on dispatch/transparent proxy.
+ * - <strm> is the stream instance.
+ * - <src> is the bind address if an explicit source address is used.
+ * - <dst> is the destination address. Must be set in every cases, except on
+ *   reverse HTTP.
+ *
+ * Returns the calculated hash.
+ */
+int64_t be_calculate_conn_hash(struct server *srv, struct stream *strm,
+                               struct session *sess,
+                               struct sockaddr_storage *src,
+                               struct sockaddr_storage *dst)
+{
+       struct proxy *be = srv ? srv->proxy : strm->be;
+       struct conn_hash_params hash_params;
+
+       /* Caller cannot set both <srv> and <strm> to NULL. */
+       BUG_ON_HOT(!srv && !strm);
+
+       /* first, set unique connection parameters and then calculate hash */
+       memset(&hash_params, 0, sizeof(hash_params));
+
+       /* 1. target */
+       hash_params.target = srv ? &srv->obj_type : strm->target;
+
+       /* 2. pool-conn-name */
+       if (srv && srv->pool_conn_name_expr) {
+               struct sample *name_smp;
+
+               name_smp = sample_fetch_as_type(be, sess, strm,
+                                               SMP_OPT_DIR_REQ | SMP_OPT_FINAL,
+                                               srv->pool_conn_name_expr, SMP_T_STR);
+               if (name_smp) {
+                       hash_params.name_prehash =
+                         conn_hash_prehash(name_smp->data.u.str.area,
+                                           name_smp->data.u.str.data);
+               }
+       }
+
+       /* 3. destination address */
+       hash_params.dst_addr = dst;
+
+       /* 4. source address */
+       hash_params.src_addr = src;
+
+       /* 5. proxy protocol */
+       if (srv && srv->pp_opts & SRV_PP_ENABLED) {
+               struct connection *cli_conn = objt_conn(strm_orig(strm));
+               int proxy_line_ret = make_proxy_line(trash.area, trash.size,
+                                                    srv, cli_conn, strm, sess);
+               if (proxy_line_ret) {
+                       hash_params.proxy_prehash =
+                         conn_hash_prehash(trash.area, proxy_line_ret);
+               }
+       }
+
+       /* 6. Custom mark, tos? */
+       if (strm->flags & (SF_BC_MARK | SF_BC_TOS)) {
+               /* mark: 32bits, tos: 8bits = 40bits
+                * last 2 bits are there to indicate if mark and/or tos are set
+                * total: 42bits:
+                *
+                * 63==== (unused) ====42    39----32 31-----------------------------0
+                * 0000000000000000000000 11 00000111 00000000000000000000000000000011
+                *                        ^^ ^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+                *                        ||    |                     |
+                *                       /  \    \                     \
+                *                      /    \    \                     \
+                *                    tos?   mark? \             mark value (32bits)
+                *                            tos value (8bits)
+                * ie: in the above example:
+                *  - mark is set, mark = 3
+                *  - tos is set, tos = 7
+                */
+               if (strm->flags & SF_BC_MARK) {
+                       hash_params.mark_tos_prehash |= strm->bc_mark;
+                       /* 41th bit: mark set */
+                       hash_params.mark_tos_prehash |= 1ULL << 40;
+               }
+               if (strm->flags & SF_BC_TOS) {
+                       hash_params.mark_tos_prehash |= (uint64_t)strm->bc_tos << 32;
+                       /* 42th bit: tos set */
+                       hash_params.mark_tos_prehash |= 1ULL << 41;
+               }
+       }
+
+       return conn_calculate_hash(&hash_params);
+}
 /*
  * This function initiates a connection to the server assigned to this stream
  * (s->target, (s->scb)->addr.to). It will assign a server if none
@@ -1554,11 +1644,8 @@ int connect_server(struct stream *s)
        int reuse = 0;
        int init_mux = 0;
        int err;
-       struct sample *name_smp = NULL;
        struct sockaddr_storage *bind_addr = NULL;
-       int proxy_line_ret;
        int64_t hash = 0;
-       struct conn_hash_params hash_params;
 
        /* in standard configuration, srv will be valid
         * it can be NULL for dispatch mode or transparent backend */
@@ -1576,12 +1663,6 @@ int connect_server(struct stream *s)
        if (err != SRV_STATUS_OK)
                return SF_ERR_INTERNAL;
 
-       if (srv && srv->pool_conn_name_expr) {
-               name_smp = sample_fetch_as_type(s->be, s->sess, s,
-                                               SMP_OPT_DIR_REQ | SMP_OPT_FINAL,
-                                               srv->pool_conn_name_expr, SMP_T_STR);
-       }
-
        /* disable reuse if websocket stream and the protocol to use is not the
         * same as the main protocol of the server.
         */
@@ -1592,65 +1673,7 @@ int connect_server(struct stream *s)
                }
        }
 
-       /* first, set unique connection parameters and then calculate hash */
-       memset(&hash_params, 0, sizeof(hash_params));
-
-       /* 1. target */
-       hash_params.target = s->target;
-
-       /* 2. pool-conn-name */
-       if (name_smp) {
-               hash_params.name_prehash =
-                 conn_hash_prehash(name_smp->data.u.str.area,
-                                   name_smp->data.u.str.data);
-       }
-
-       /* 3. destination address */
-       hash_params.dst_addr = s->scb->dst;
-
-       /* 4. source address */
-       hash_params.src_addr = bind_addr;
-
-       /* 5. proxy protocol */
-       if (srv && (srv->pp_opts & SRV_PP_ENABLED)) {
-               proxy_line_ret = make_proxy_line(trash.area, trash.size, srv, cli_conn, s, strm_sess(s));
-               if (proxy_line_ret) {
-                       hash_params.proxy_prehash =
-                         conn_hash_prehash(trash.area, proxy_line_ret);
-               }
-       }
-
-       /* 6. Custom mark, tos? */
-       if (s->flags & (SF_BC_MARK | SF_BC_TOS)) {
-               /* mark: 32bits, tos: 8bits = 40bits
-                * last 2 bits are there to indicate if mark and/or tos are set
-                * total: 42bits:
-                *
-                * 63==== (unused) ====42    39----32 31-----------------------------0
-                * 0000000000000000000000 11 00000111 00000000000000000000000000000011
-                *                        ^^ ^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-                *                        ||    |                     |
-                *                       /  \    \                     \
-                *                      /    \    \                     \
-                *                    tos?   mark? \             mark value (32bits)
-                *                            tos value (8bits)
-                * ie: in the above example:
-                *  - mark is set, mark = 3
-                *  - tos is set, tos = 7
-                */
-               if (s->flags & SF_BC_MARK) {
-                       hash_params.mark_tos_prehash |= s->bc_mark;
-                       /* 41th bit: mark set */
-                       hash_params.mark_tos_prehash |= 1ULL << 40;
-               }
-               if (s->flags & SF_BC_TOS) {
-                       hash_params.mark_tos_prehash |= (uint64_t)s->bc_tos << 32;
-                       /* 42th bit: tos set */
-                       hash_params.mark_tos_prehash |= 1ULL << 41;
-               }
-       }
-
-       hash = conn_calculate_hash(&hash_params);
+       hash = be_calculate_conn_hash(srv, s, s->sess, bind_addr, s->scb->dst);
 
        /* first, search for a matching connection in the session's idle conns */
        srv_conn = session_get_conn(s->sess, s->target, hash);