server/connection.c

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2000 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
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 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 * Portions of this software are based upon public domain software
 * originally written at the National Center for Supercomputing Applications,
 * University of Illinois, Urbana-Champaign.
 */

#define CORE_PRIVATE
#include "ap_config.h"
#include "httpd.h"
#include "http_connection.h"
#include "http_request.h"
#include "http_protocol.h"
#include "ap_mpm.h"
#include "mpm_status.h"
#include "http_config.h"
#include "http_vhost.h"

HOOK_STRUCT(
	    HOOK_LINK(pre_connection)
	    HOOK_LINK(process_connection)
)

IMPLEMENT_HOOK_VOID(pre_connection,(conn_rec *c),(c))
IMPLEMENT_HOOK_RUN_FIRST(int,process_connection,(conn_rec *c),(c),DECLINED)

/*
 * More machine-dependent networking gooo... on some systems,
 * you've got to be *really* sure that all the packets are acknowledged
 * before closing the connection, since the client will not be able
 * to see the last response if their TCP buffer is flushed by a RST
 * packet from us, which is what the server's TCP stack will send
 * if it receives any request data after closing the connection.
 *
 * In an ideal world, this function would be accomplished by simply
 * setting the socket option SO_LINGER and handling it within the
 * server's TCP stack while the process continues on to the next request.
 * Unfortunately, it seems that most (if not all) operating systems
 * block the server process on close() when SO_LINGER is used.
 * For those that don't, see USE_SO_LINGER below.  For the rest,
 * we have created a home-brew lingering_close.
 *
 * Many operating systems tend to block, puke, or otherwise mishandle
 * calls to shutdown only half of the connection.  You should define
 * NO_LINGCLOSE in ap_config.h if such is the case for your system.
 */
#ifndef MAX_SECS_TO_LINGER
#define MAX_SECS_TO_LINGER 30
#endif

#ifdef USE_SO_LINGER
#define NO_LINGCLOSE		/* The two lingering options are exclusive */

static void sock_enable_linger(int s) 
{
    struct linger li;                 

    li.l_onoff = 1;
    li.l_linger = MAX_SECS_TO_LINGER;

    if (setsockopt(s, SOL_SOCKET, SO_LINGER, 
		   (char *) &li, sizeof(struct linger)) < 0) {
	ap_log_error(APLOG_MARK, APLOG_WARNING, server_conf,
	            "setsockopt: (SO_LINGER)");
	/* not a fatal error */
    }
}

#else
#define sock_enable_linger(s)	/* NOOP */
#endif /* USE_SO_LINGER */

#ifndef NO_LINGCLOSE

/* we now proceed to read from the client until we get EOF, or until
 * MAX_SECS_TO_LINGER has passed.  the reasons for doing this are
 * documented in a draft:
 *
 * http://www.ics.uci.edu/pub/ietf/http/draft-ietf-http-connection-00.txt
 *
 * in a nutshell -- if we don't make this effort we risk causing
 * TCP RST packets to be sent which can tear down a connection before
 * all the response data has been sent to the client.
 */

static void lingering_close(conn_rec *c)
{
    char dummybuf[512];
    ap_time_t start;
    ap_ssize_t nbytes;
    ap_status_t rc;
    int timeout;

    /* Send any leftover data to the client, but never try to again */

    if (ap_bflush(c->client) != APR_SUCCESS) {
        ap_bclose(c->client);
        return;
    }

    /* Shut down the socket for write, which will send a FIN
     * to the peer.
     */
    
    if (ap_bshutdown(c->client, 1) != APR_SUCCESS
        || ap_is_aborted(c)) {
        ap_bclose(c->client);
        return;
    }

    /* Read all data from the peer until we reach "end-of-file" (FIN
     * from peer) or we've exceeded our overall timeout.
     */
    
    start = ap_now();
    timeout = MAX_SECS_TO_LINGER;
    for (;;) {
        ap_bsetopt(c->client, BO_TIMEOUT, &timeout);
        rc = ap_bread(c->client, dummybuf, sizeof(dummybuf),
                      &nbytes);
        if (rc != APR_SUCCESS || nbytes == 0) break;

        /* how much time has elapsed? */
        timeout = (int)((ap_now() - start) / AP_USEC_PER_SEC);
        if (timeout >= MAX_SECS_TO_LINGER) break;

        /* figure out the new timeout */
        timeout = MAX_SECS_TO_LINGER - timeout;
    }

    ap_bclose(c->client);
}

#endif /* ndef NO_LINGCLOSE */

CORE_EXPORT(void) ap_process_connection(conn_rec *c)
{
    ap_update_vhost_given_ip(c);

    ap_run_pre_connection(c);

    ap_run_process_connection(c);

    /*
     * Close the connection, being careful to send out whatever is still
     * in our buffers.  If possible, try to avoid a hard close until the
     * client has ACKed our FIN and/or has stopped sending us data.
     */

#ifdef NO_LINGCLOSE
    ap_bclose(c->client);	/* just close it */
#else
    if (!c->aborted
	&& c->client
	/* && (c->client->fd >= 0) */ ) {

	lingering_close(c);
    }
    else {
	ap_bsetflag(c->client, B_EOUT, 1);
	ap_bclose(c->client);
    }
#endif
}

int ap_process_http_connection(conn_rec *c)
    {
    request_rec *r;

    /*
     * Read and process each request found on our connection
     * until no requests are left or we decide to close.
     */

    ap_update_connection_status(c->id, "Status", "Reading");
    while ((r = ap_read_request(c)) != NULL) {

	/* process the request if it was read without error */

        ap_update_connection_status(c->id, "Status", "Writing");
	if (r->status == HTTP_OK)
	    ap_process_request(r);

	if (!c->keepalive || c->aborted)
	    break;

        ap_update_connection_status(c->id, "Status", "Keepalive");
	ap_destroy_pool(r->pool);

	if (ap_graceful_stop_signalled()) {
	    /* XXX: hey wait, this should do a lingering_close! */
	    ap_bclose(c->client);
	    return OK;
	}
    }

    ap_reset_connection_status(c->id);
    return OK;
}

/* Clearly some of this stuff doesn't belong in a generalised connection
   structure, but for now...
*/

conn_rec *ap_new_connection(ap_pool_t *p, server_rec *server, BUFF *inout,
			    const struct sockaddr_in *remaddr,
			    const struct sockaddr_in *saddr, long id)
{
    conn_rec *conn = (conn_rec *) ap_pcalloc(p, sizeof(conn_rec));

    /* Got a connection structure, so initialize what fields we can
     * (the rest are zeroed out by pcalloc).
     */

    conn->conn_config=ap_create_conn_config(p);

    conn->pool = p;
    conn->local_addr = *saddr;
    conn->local_ip = ap_pstrdup(conn->pool,
				inet_ntoa(conn->local_addr.sin_addr));
    conn->base_server = server;
    conn->client = inout;

    conn->remote_addr = *remaddr;
    conn->remote_ip = ap_pstrdup(conn->pool,
			      inet_ntoa(conn->remote_addr.sin_addr));
    
    conn->id = id;

    return conn;
}



conn_rec *ap_new_apr_connection(ap_pool_t *p, server_rec *server, BUFF *inout,
			    const ap_socket_t *conn_socket, long id)
{
    struct sockaddr_in *sa_local, *sa_remote;

    ap_get_local_name(&sa_local, conn_socket);
    ap_get_remote_name(&sa_remote, conn_socket);
    return ap_new_connection(p, server, inout, sa_remote, sa_local, id);
}