forward.c

-

/*
 * $Id: forward.c,v 1.54.2.6 1999/07/07 01:52:50 wessels Exp $
 *
 * DEBUG: section 17    Request Forwarding
 * AUTHOR: Duane Wessels
 *
 * SQUID Internet Object Cache  http://squid.nlanr.net/Squid/
 * ----------------------------------------------------------
 *
 *  Squid is the result of efforts by numerous individuals from the
 *  Internet community.  Development is led by Duane Wessels of the
 *  National Laboratory for Applied Network Research and funded by the
 *  National Science Foundation.  Squid is Copyrighted (C) 1998 by
 *  Duane Wessels and the University of California San Diego.  Please
 *  see the COPYRIGHT file for full details.  Squid incorporates
 *  software developed and/or copyrighted by other sources.  Please see
 *  the CREDITS file for full details.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *  
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *  
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 *
 */


#include "squid.h"

static PSC fwdStartComplete;
static void fwdDispatch(FwdState *);
static void fwdConnectStart(void *);	/* should be same as EVH */
static void fwdStateFree(FwdState * fwdState);
static PF fwdConnectTimeout;
static PF fwdServerClosed;
static CNCB fwdConnectDone;
static int fwdCheckRetry(FwdState * fwdState);
static int fwdReforward(FwdState *);
static void fwdStartFail(FwdState *);
static void fwdLogReplyStatus(int tries, http_status status);
static OBJH fwdStats;
static STABH fwdAbort;

#define MAX_FWD_STATS_IDX 9
static int FwdReplyCodes[MAX_FWD_STATS_IDX + 1][HTTP_INVALID_HEADER + 1];

static void
fwdServerFree(FwdServer * fs)
{
    if (fs->peer)
	cbdataUnlock(fs->peer);
    memFree(fs, MEM_FWD_SERVER);
}

static void
fwdStateFree(FwdState * fwdState)
{
    StoreEntry *e = fwdState->entry;
    int sfd;
    debug(17, 3) ("fwdStateFree: %p\n", fwdState);
    assert(e->mem_obj);
    if (e->store_status == STORE_PENDING) {
	if (e->mem_obj->inmem_hi == 0) {
	    assert(fwdState->err);
	    errorAppendEntry(e, fwdState->err);
	    fwdState->err = NULL;
	} else {
	    EBIT_CLR(e->flags, ENTRY_FWD_HDR_WAIT);
	    storeComplete(e);
	    storeReleaseRequest(e);
	}
    }
    if (storePendingNClients(e) > 0)
	assert(!EBIT_TEST(e->flags, ENTRY_FWD_HDR_WAIT));
    fwdServersFree(&fwdState->servers);
    requestUnlink(fwdState->request);
    fwdState->request = NULL;
    if (fwdState->err)
	errorStateFree(fwdState->err);
    storeUnregisterAbort(e);
    storeUnlockObject(e);
    fwdState->entry = NULL;
    sfd = fwdState->server_fd;
    if (sfd > -1) {
	comm_remove_close_handler(sfd, fwdServerClosed, fwdState);
	fwdState->server_fd = -1;
	debug(17, 3) ("fwdStateFree: closing FD %d\n", sfd);
	comm_close(sfd);
    }
    cbdataFree(fwdState);
}

static int
fwdCheckRetry(FwdState * fwdState)
{
    if (fwdState->entry->store_status != STORE_PENDING)
	return 0;
    if (fwdState->entry->mem_obj->inmem_hi > 0)
	return 0;
    if (fwdState->n_tries > 10)
	return 0;
    if (squid_curtime - fwdState->start > 120)
	return 0;
    if (fwdState->flags.dont_retry)
	return 0;
    if (pumpMethod(fwdState->request->method))
	if (0 == pumpRestart(fwdState->request))
	    return 0;
    return 1;
}

static void
fwdServerClosed(int fd, void *data)
{
    FwdState *fwdState = data;
    debug(17, 2) ("fwdServerClosed: FD %d %s\n", fd, storeUrl(fwdState->entry));
    assert(fwdState->server_fd == fd);
    fwdState->server_fd = -1;
    if (fwdCheckRetry(fwdState)) {
	debug(17, 3) ("fwdServerClosed: re-forwarding (%d tries, %d secs)\n",
	    fwdState->n_tries,
	    (int) (squid_curtime - fwdState->start));
	if (fwdState->servers->next) {
	    /* cycle */
	    FwdServer *fs = fwdState->servers;
	    FwdServer **T;
	    fwdState->servers = fs->next;
	    for (T = &fwdState->servers; *T; T = &(*T)->next);
	    *T = fs;
	    fs->next = NULL;
	}
	/* use eventAdd to break potential call sequence loops */
	eventAdd("fwdConnectStart", fwdConnectStart, fwdState, 0.0, 1);
    } else {
	fwdStateFree(fwdState);
    }
}

static void
fwdConnectDone(int server_fd, int status, void *data)
{
    FwdState *fwdState = data;
    static FwdState *current = NULL;
    FwdServer *fs = fwdState->servers;
    ErrorState *err;
    request_t *request = fwdState->request;
    assert(current != fwdState);
    current = fwdState;
    assert(fwdState->server_fd == server_fd);
    if (status == COMM_ERR_DNS) {
	fwdState->flags.dont_retry = 1;
	debug(17, 4) ("fwdConnectDone: Unknown host: %s\n",
	    request->host);
	err = errorCon(ERR_DNS_FAIL, HTTP_SERVICE_UNAVAILABLE);
	err->dnsserver_msg = xstrdup(dns_error_message);
	err->request = requestLink(request);
	fwdFail(fwdState, err);
	comm_close(server_fd);
    } else if (status != COMM_OK) {
	assert(fs);
	err = errorCon(ERR_CONNECT_FAIL, HTTP_SERVICE_UNAVAILABLE);
	err->xerrno = errno;
	if (fs->peer) {
	    err->host = xstrdup(fs->peer->host);
	    err->port = fs->peer->http_port;
	} else {
	    err->host = xstrdup(request->host);
	    err->port = request->port;
	}
	err->request = requestLink(request);
	fwdFail(fwdState, err);
	if (fs->peer)
	    peerCheckConnectStart(fs->peer);
	comm_close(server_fd);
    } else {
	debug(17, 3) ("fwdConnectDone: FD %d: '%s'\n", server_fd, storeUrl(fwdState->entry));
	fd_note(server_fd, storeUrl(fwdState->entry));
	fd_table[server_fd].uses++;
	fwdDispatch(fwdState);
    }
    current = NULL;
}

static void
fwdConnectTimeout(int fd, void *data)
{
    FwdState *fwdState = data;
    StoreEntry *entry = fwdState->entry;
    ErrorState *err;
    debug(17, 2) ("fwdConnectTimeout: FD %d: '%s'\n", fd, storeUrl(entry));
    assert(fd == fwdState->server_fd);
    if (entry->mem_obj->inmem_hi == 0) {
	err = errorCon(ERR_CONNECT_FAIL, HTTP_GATEWAY_TIMEOUT);
	err->request = requestLink(fwdState->request);
	err->xerrno = ETIMEDOUT;
	fwdFail(fwdState, err);
    }
    comm_close(fd);
}

static void
fwdConnectStart(void *data)
{
    FwdState *fwdState = data;
    const char *url = storeUrl(fwdState->entry);
    int fd;
    ErrorState *err;
    FwdServer *fs = fwdState->servers;
    const char *host;
    unsigned short port;
    assert(fs);
    assert(fwdState->server_fd == -1);
    debug(17, 3) ("fwdConnectStart: %s\n", url);
    if (fs->peer) {
	host = fs->peer->host;
	port = fs->peer->http_port;
    } else {
	host = fwdState->request->host;
	port = fwdState->request->port;
    }
    hierarchyNote(&fwdState->request->hier, fs->code, host);
    if ((fd = pconnPop(host, port)) >= 0) {
	debug(17, 3) ("fwdConnectStart: reusing pconn FD %d\n", fd);
	fwdState->server_fd = fd;
	fwdState->n_tries++;
	comm_add_close_handler(fd, fwdServerClosed, fwdState);
	fwdConnectDone(fd, COMM_OK, fwdState);
	return;
    }
    fd = comm_open(SOCK_STREAM,
	0,
	Config.Addrs.tcp_outgoing,
	0,
	COMM_NONBLOCKING,
	url);
    if (fd < 0) {
	debug(50, 4) ("fwdConnectStart: %s\n", xstrerror());
	err = errorCon(ERR_SOCKET_FAILURE, HTTP_INTERNAL_SERVER_ERROR);
	err->xerrno = errno;
	err->request = requestLink(fwdState->request);
	fwdFail(fwdState, err);
	fwdStateFree(fwdState);
	return;
    }
    fwdState->server_fd = fd;
    fwdState->n_tries++;
    comm_add_close_handler(fd, fwdServerClosed, fwdState);
    commSetTimeout(fd,
	Config.Timeout.connect,
	fwdConnectTimeout,
	fwdState);
    commConnectStart(fd, host, port, fwdConnectDone, fwdState);
}

static void
fwdStartComplete(FwdServer * servers, void *data)
{
    FwdState *fwdState = data;
    debug(17, 3) ("fwdStartComplete: %s\n", storeUrl(fwdState->entry));
    if (servers != NULL) {
	fwdState->servers = servers;
	fwdConnectStart(fwdState);
    } else {
	fwdStartFail(fwdState);
    }
}

static void
fwdStartFail(FwdState * fwdState)
{
    ErrorState *err;
    debug(17, 3) ("fwdStartFail: %s\n", storeUrl(fwdState->entry));
    err = errorCon(ERR_CANNOT_FORWARD, HTTP_SERVICE_UNAVAILABLE);
    err->request = requestLink(fwdState->request);
    err->xerrno = errno;
    fwdFail(fwdState, err);
    fwdStateFree(fwdState);
}

static void
fwdDispatch(FwdState * fwdState)
{
    peer *p;
    request_t *request = fwdState->request;
    StoreEntry *entry = fwdState->entry;
    debug(17, 3) ("fwdDispatch: FD %d: Fetching '%s %s'\n",
	fwdState->client_fd,
	RequestMethodStr[request->method],
	storeUrl(entry));
    /*assert(!EBIT_TEST(entry->flags, ENTRY_DISPATCHED)); */
    assert(entry->ping_status != PING_WAITING);
    assert(entry->lock_count);
    EBIT_SET(entry->flags, ENTRY_DISPATCHED);
    netdbPingSite(request->host);
    /*