SNI: reuse selected configuration for all requests in a connection.

Previously, only the first request in a connection was assigned the
configuration selected by SNI.  All subsequent requests initially
used the default server's configuration, ignoring SNI, which was
wrong.

Now all subsequent requests in a connection will initially use the
configuration selected by SNI.  This is done by storing a pointer
to configuration in http connection object.  It points to default
server's configuration initially, but changed upon receipt of SNI.

(The request's configuration can be further refined when parsing
the request line and Host: header.)

This change was not made specific to SNI as it also allows slightly
faster access to configuration without the request object.

src/http/ngx_http.h

@@ -27,11 +27,11 @@ typedef u_char *(*ngx_http_log_handler_pt)(ngx_http_request_t *r,
 
 
 #include <ngx_http_variables.h>
+#include <ngx_http_config.h>
 #include <ngx_http_request.h>
 #include <ngx_http_script.h>
 #include <ngx_http_upstream.h>
 #include <ngx_http_upstream_round_robin.h>
-#include <ngx_http_config.h>
 #include <ngx_http_busy_lock.h>
 #include <ngx_http_core_module.h>
 

src/http/ngx_http_request.c

@@ -292,6 +292,9 @@ ngx_http_init_connection(ngx_connection_t *c)
         }
     }
 
+    /* the default server configuration for the address:port */
+    hc->conf_ctx = hc->addr_conf->default_server->ctx;
+
     ctx = ngx_palloc(c->pool, sizeof(ngx_http_log_ctx_t));
     if (ctx == NULL) {
         ngx_http_close_connection(c);
@@ -399,12 +402,9 @@ ngx_http_init_request(ngx_event_t *rev)
 
     r->connection = c;
 
-    /* the default server configuration for the address:port */
-    cscf = hc->addr_conf->default_server;
-
-    r->main_conf = cscf->ctx->main_conf;
-    r->srv_conf = cscf->ctx->srv_conf;
-    r->loc_conf = cscf->ctx->loc_conf;
+    r->main_conf = hc->conf_ctx->main_conf;
+    r->srv_conf = hc->conf_ctx->srv_conf;
+    r->loc_conf = hc->conf_ctx->loc_conf;
 
     rev->handler = ngx_http_process_request_line;
     r->read_event_handler = ngx_http_block_reading;
@@ -449,6 +449,8 @@ ngx_http_init_request(ngx_event_t *rev)
 
     ngx_http_set_connection_log(r->connection, clcf->error_log);
 
+    cscf = ngx_http_get_module_srv_conf(r, ngx_http_core_module);
+
     if (c->buffer == NULL) {
         c->buffer = ngx_create_temp_buf(c->pool,
                                         cscf->client_header_buffer_size);
@@ -689,6 +691,8 @@ ngx_http_ssl_servername(ngx_ssl_conn_t *ssl_conn, int *ad, void *arg)
         return SSL_TLSEXT_ERR_NOACK;
     }
 
+    hc->conf_ctx = cscf->ctx;
+
     r->srv_conf = cscf->ctx->srv_conf;
     r->loc_conf = cscf->ctx->loc_conf;
 

src/http/ngx_http_request.h

@@ -293,6 +293,7 @@ typedef struct ngx_http_addr_conf_s  ngx_http_addr_conf_t;
 
 typedef struct {
     ngx_http_addr_conf_t             *addr_conf;
+    ngx_http_conf_ctx_t              *conf_ctx;
 
     ngx_http_request_t               *request;