vhost.c

    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;
            }
        }
        last_s = s;

        /* Fallback: does it match the virthost from the sar? */
        if (!strcasecmp(host, sar->virthost)) {
            /* only the first match is used */
            if (virthost_s == NULL) {
                virthost_s = s;
            }
        }
    }

    /* If ServerName and ServerAlias check failed, we end up here.  If it
     * matches a VirtualHost, virthost_s is set. Use that as fallback
     */
    if (virthost_s) {
        s = virthost_s;
        goto found;
    }

    return;

found:
    /* s is the first matching server, we're done */
    r->server = s;
}


static void check_serverpath(request_rec *r)
{
    server_rec *s;
    server_rec *last_s;
    name_chain *src;
    apr_port_t port;

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

    /*
     * This is in conjunction with the ServerPath code in http_core, so we
     * get the right host attached to a non- Host-sending request.
     *
     * See the comment in check_hostalias about how each vhost can be
     * listed multiple times.
     */

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

        s = src->server;
        if (s == last_s) {
            continue;
        }
        last_s = s;

        if (s->path && !strncmp(r->uri, s->path, s->pathlen) &&
            (s->path[s->pathlen - 1] == '/' ||
             r->uri[s->pathlen] == '/' ||
             r->uri[s->pathlen] == '\0')) {
            r->server = s;
            return;
        }
    }
}

static APR_INLINE const char *construct_host_header(request_rec *r,
                                                    int is_v6literal)
{
    struct iovec iov[5];
    apr_size_t nvec = 0;
    /*
     * We cannot use ap_get_server_name/port here, because we must
     * ignore UseCanonicalName/Port.
     */
    if (is_v6literal) {
        iov[nvec].iov_base = "[";
        iov[nvec].iov_len = 1;
        nvec++;
    }
    iov[nvec].iov_base = (void *)r->hostname;
    iov[nvec].iov_len = strlen(r->hostname);
    nvec++;
    if (is_v6literal) {
        iov[nvec].iov_base = "]";
        iov[nvec].iov_len = 1;
        nvec++;
    }
    if (r->parsed_uri.port_str) {
        iov[nvec].iov_base = ":";
        iov[nvec].iov_len = 1;
        nvec++;
        iov[nvec].iov_base = r->parsed_uri.port_str;
        iov[nvec].iov_len = strlen(r->parsed_uri.port_str);
        nvec++;
    }
    return apr_pstrcatv(r->pool, iov, nvec, NULL);
}

AP_DECLARE(void) ap_update_vhost_from_headers(request_rec *r)
{
    core_server_config *conf = ap_get_core_module_config(r->server->module_config);
    const char *host_header = apr_table_get(r->headers_in, "Host");
    int is_v6literal = 0;
    int have_hostname_from_url = 0;

    if (r->hostname) {
        /*
         * If there was a host part in the Request-URI, ignore the 'Host'
         * header.
         */
        have_hostname_from_url = 1;
        is_v6literal = fix_hostname(r, NULL, conf->http_conformance);
    }
    else if (host_header != NULL) {
        is_v6literal = fix_hostname(r, host_header, conf->http_conformance);
    }
    if (r->status != HTTP_OK)
        return;

    if (conf->http_conformance != AP_HTTP_CONFORMANCE_UNSAFE) {
        /*
         * If we have both hostname from an absoluteURI and a Host header,
         * we must ignore the Host header (RFC 2616 5.2).
         * To enforce this, we reset the Host header to the value from the
         * request line.
         */
        if (have_hostname_from_url && host_header != NULL) {
            const char *repl = construct_host_header(r, is_v6literal);
            apr_table_setn(r->headers_in, "Host", repl);
            ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(02417)
                          "Replacing host header '%s' with host '%s' given "
                          "in the request uri", host_header, repl);
        }
    }

    /* check if we tucked away a name_chain */
    if (r->connection->vhost_lookup_data) {
        if (r->hostname)
            check_hostalias(r);
        else
            check_serverpath(r);
    }
}

/**
 * For every virtual host on this connection, call func_cb.
 */
AP_DECLARE(int) ap_vhost_iterate_given_conn(conn_rec *conn,
                                            ap_vhost_iterate_conn_cb func_cb,
                                            void* baton)
{
    server_rec *s;
    server_rec *last_s;
    name_chain *src;
    apr_port_t port;
    int rv = 0;

    if (conn->vhost_lookup_data) {
        last_s = NULL;
        port = conn->local_addr->port;

        for (src = conn->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 (s == last_s) {
                /* we've already done a callback for this vhost. */
                continue;
            }

            last_s = s;

            rv = func_cb(baton, conn, s);

            if (rv != 0) {
                break;
            }
        }
    }
    else {
        rv = func_cb(baton, conn, conn->base_server);
    }

    return rv;
}

/* Called for a new connection which has a known local_addr.  Note that the
 * new connection is assumed to have conn->server == main server.
 */
AP_DECLARE(void) ap_update_vhost_given_ip(conn_rec *conn)
{
    ipaddr_chain *trav;
    apr_port_t port;

    /* scan the hash table for an exact match first */
    trav = find_ipaddr(conn->local_addr);

    if (trav) {
        /* save the name_chain for later in case this is a name-vhost */
        conn->vhost_lookup_data = trav->names;
        conn->base_server = trav->server;
        return;
    }

    /* maybe there's a default server or wildcard name-based vhost
     * matching this port
     */
    port = conn->local_addr->port;

    trav = find_default_server(port);
    if (trav) {
        conn->vhost_lookup_data = trav->names;
        conn->base_server = trav->server;
        return;
    }

    /* otherwise we're stuck with just the main server
     * and no name-based vhosts
     */
    conn->vhost_lookup_data = NULL;
}