Function update_server_from_aliases

server/vhost.c:1000–1090

* Updates r->server from ServerName/ServerAlias. Per the interaction * of ip and name-based vhosts, it only looks in the best match from the * connection-level ip-based matching. * Returns HTTP_BAD_REQUEST if there was no match. */

 * Returns HTTP_BAD_REQUEST if there was no match.
 */
static int update_server_from_aliases(request_rec *r)
{
    /*
     * Even if the request has a Host: header containing a port we ignore
     * that port.  We always use the physical port of the socket.  There
     * are a few reasons for this:
     *
     * - the default of 80 or 443 for SSL is easier to handle this way
     * - there is less of a possibility of a security problem
     * - it simplifies the data structure
     * - the client may have no idea that a proxy somewhere along the way
     *   translated the request to another ip:port
     * - except for the addresses from the VirtualHost line, none of the other
     *   names we'll match have ports associated with them
     */
    const char *host = r->hostname;
    apr_port_t port;
    server_rec *s;
    server_rec *virthost_s;
    server_rec *last_s;
    name_chain *src;

    virthost_s = NULL;
    last_s = NULL;

    port = r->connection->local_addr->port;

    /* Recall that the name_chain is a list of server_addr_recs, some of
     * whose ports may not match.  Also each server may appear more than
     * once in the chain -- specifically, it will appear once for each
     * address from its VirtualHost line which matched.  We only want to
     * do the full ServerName/ServerAlias comparisons once for each
     * server, fortunately we know that all the VirtualHost addresses for
     * a single server are adjacent to each other.
     */

    for (src = r->connection->vhost_lookup_data; src; src = src->next) {
        server_addr_rec *sar;

        /* We only consider addresses on the name_chain which have a matching
         * port
         */
        sar = src->sar;
        if (sar->host_port != 0 && port != sar->host_port) {
            continue;
        }

        s = src->server;

        /* If we still need to do ServerName and ServerAlias checks for this
         * server, do them now.
         */
        if (s != last_s) {
            /* does it match any ServerName or ServerAlias directive? */
            if (matches_aliases(s, host)) {
                goto found;
            }
        }