neighbors.c

-

/*
 * $Id: neighbors.c,v 1.270.2.4 1999/07/07 02:02:26 wessels Exp $
 *
 * DEBUG: section 15    Neighbor Routines
 * AUTHOR: Harvest Derived
 *
 * 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"

/* count mcast group peers every 15 minutes */
#define MCAST_COUNT_RATE 900

static int peerAllowedToUse(const peer *, request_t *);
static int peerWouldBePinged(const peer *, request_t *);
static void neighborRemove(peer *);
static void neighborAlive(peer *, const MemObject *, const icp_common_t *);
#if USE_HTCP
static void neighborAliveHtcp(peer *, const MemObject *, const htcpReplyData *);
#endif
static void neighborCountIgnored(peer *);
static void peerRefreshDNS(void *);
static IPH peerDNSConfigure;
static EVH peerCheckConnect;
static IPH peerCheckConnect2;
static CNCB peerCheckConnectDone;
static void peerCountMcastPeersDone(void *data);
static void peerCountMcastPeersStart(void *data);
static void peerCountMcastPeersSchedule(peer * p, time_t when);
static IRCB peerCountHandleIcpReply;
static void neighborIgnoreNonPeer(const struct sockaddr_in *, icp_opcode);
static OBJH neighborDumpPeers;
static OBJH neighborDumpNonPeers;
static void dump_peers(StoreEntry * sentry, peer * peers);

static icp_common_t echo_hdr;
static u_short echo_port;

static int NLateReplies = 0;
static peer *first_ping = NULL;

char *
neighborTypeStr(const peer * p)
{
    if (p->type == PEER_NONE)
	return "Non-Peer";
    if (p->type == PEER_SIBLING)
	return "Sibling";
    if (p->type == PEER_MULTICAST)
	return "Multicast Group";
    return "Parent";
}


peer *
whichPeer(const struct sockaddr_in * from)
{
    int j;
    u_short port = ntohs(from->sin_port);
    struct in_addr ip = from->sin_addr;
    peer *p = NULL;
    debug(15, 3) ("whichPeer: from %s port %d\n", inet_ntoa(ip), port);
    for (p = Config.peers; p; p = p->next) {
	for (j = 0; j < p->n_addresses; j++) {
	    if (ip.s_addr == p->addresses[j].s_addr && port == p->icp.port) {
		return p;
	    }
	}
    }
    return NULL;
}

peer_t
neighborType(const peer * p, const request_t * request)
{
    const struct _domain_type *d = NULL;
    for (d = p->typelist; d; d = d->next) {
	if (matchDomainName(d->domain, request->host))
	    if (d->type != PEER_NONE)
		return d->type;
    }
    return p->type;
}

/*
 * peerAllowedToUse
 *
 * this function figures out if it is appropriate to fetch REQUEST
 * from PEER.
 */
static int
peerAllowedToUse(const peer * p, request_t * request)
{
    const struct _domain_ping *d = NULL;
    int do_ping = 1;
    aclCheck_t checklist;
    assert(request != NULL);
    if (neighborType(p, request) == PEER_SIBLING) {
	if (request->flags.nocache)
	    return 0;
	if (request->flags.refresh)
	    return 0;
	if (request->flags.loopdetect)
	    return 0;
	if (request->flags.need_validation)
	    return 0;
    }
    if (p->peer_domain == NULL && p->access == NULL)
	return do_ping;
    do_ping = 0;
    for (d = p->peer_domain; d; d = d->next) {
	if (matchDomainName(d->domain, request->host)) {
	    do_ping = d->do_ping;
	    break;
	}
	do_ping = !d->do_ping;
    }
    if (p->peer_domain && 0 == do_ping)
	return do_ping;
    if (p->access == NULL)
	return do_ping;
    checklist.src_addr = request->client_addr;
    checklist.my_addr = request->my_addr;
    checklist.request = request;
    return aclCheckFast(p->access, &checklist);
}

/* Return TRUE if it is okay to send an ICP request to this peer.   */
static int
peerWouldBePinged(const peer * p, request_t * request)
{
    if (!peerAllowedToUse(p, request))
	return 0;
    if (p->options.no_query)
	return 0;
    if (p->options.mcast_responder)
	return 0;
    /* the case below seems strange, but can happen if the
     * URL host is on the other side of a firewall */
    if (p->type == PEER_SIBLING)
	if (!request->flags.hierarchical)
	    return 0;
    if (p->icp.port == echo_port)
	if (!neighborUp(p))
	    return 0;
    if (p->n_addresses == 0)
	return 0;
    return 1;
}

/* Return TRUE if it is okay to send an HTTP request to this peer. */
int
peerHTTPOkay(const peer * p, request_t * request)
{
    if (!peerAllowedToUse(p, request))
	return 0;
    if (!neighborUp(p))
	return 0;
    return 1;
}

int
neighborsCount(request_t * request)
{
    peer *p = NULL;
    int count = 0;
    for (p = Config.peers; p; p = p->next)
	if (peerWouldBePinged(p, request))
	    count++;
    debug(15, 3) ("neighborsCount: %d\n", count);
    return count;
}

peer *
getSingleParent(request_t * request)
{
    peer *p = NULL;
    peer *q = NULL;
    for (q = Config.peers; q; q = q->next) {
	if (!peerHTTPOkay(q, request))
	    continue;
	if (neighborType(q, request) != PEER_PARENT)
	    return NULL;	/* oops, found SIBLING */
	if (p)
	    return NULL;	/* oops, found second parent */
	p = q;
    }
    if (p != NULL && !p->options.no_query)
	return NULL;
    debug(15, 3) ("getSingleParent: returning %s\n", p ? p->host : "NULL");
    return p;
}

peer *
getFirstUpParent(request_t * request)
{
    peer *p = NULL;
    for (p = Config.peers; p; p = p->next) {
	if (!neighborUp(p))
	    continue;
	if (neighborType(p, request) != PEER_PARENT)
	    continue;
	if (!peerHTTPOkay(p, request))
	    continue;
	break;
    }
    debug(15, 3) ("getFirstUpParent: returning %s\n", p ? p->host : "NULL");
    return p;
}

peer *
getRoundRobinParent(request_t * request)
{
    peer *p;
    peer *q = NULL;
    for (p = Config.peers; p; p = p->next) {
	if (!p->options.roundrobin)
	    continue;
	if (neighborType(p, request) != PEER_PARENT)
	    continue;
	if (!peerHTTPOkay(p, request))
	    continue;
	if (q && q->rr_count < p->rr_count)
	    continue;
	q = p;
    }
    if (q)
	q->rr_count++;
    debug(15, 3) ("getRoundRobinParent: returning %s\n", q ? q->host : "NULL");
    return q;
}

peer *
getDefaultParent(request_t * request)
{
    peer *p = NULL;
    for (p = Config.peers; p; p = p->next) {
	if (neighborType(p, request) != PEER_PARENT)
	    continue;
	if (!p->options.default_parent)
	    continue;
	if (!peerHTTPOkay(p, request))
	    continue;
	debug(15, 3) ("getDefaultParent: returning %s\n", p->host);
	return p;
    }
    debug(15, 3) ("getDefaultParent: returning NULL\n");
    return NULL;
}

peer *
getAnyParent(request_t * request)
{
    peer *p = NULL;
    for (p = Config.peers; p; p = p->next) {
	if (neighborType(p, request) != PEER_PARENT)
	    continue;
	if (!peerHTTPOkay(p, request))
	    continue;
	debug(15, 3) ("getAnyParent: returning %s\n", p->host);
	return p;
    }
    debug(15, 3) ("getAnyParent: returning NULL\n");
    return NULL;
}

peer *
getNextPeer(peer * p)
{
    return p->next;
}

peer *
getFirstPeer(void)
{
    return Config.peers;
}

static void
neighborRemove(peer * target)
{
    peer *p = NULL;
    peer **P = NULL;
    p = Config.peers;
    P = &Config.peers;
    while (p) {
	if (target == p)
	    break;
	P = &p->next;
	p = p->next;
    }
    if (p) {
	*P = p->next;
	cbdataFree(p);
	Config.npeers--;
    }
    first_ping = Config.peers;
}

void
neighbors_open(int fd)
{
    struct sockaddr_in name;
    socklen_t len = sizeof(struct sockaddr_in);
    struct servent *sep = NULL;
    memset(&name, '\0', sizeof(struct sockaddr_in));
    if (getsockname(fd, (struct sockaddr *) &name, &len) < 0)
	debug(15, 1) ("getsockname(%d,%p,%p) failed.\n", fd, &name, &len);
    peerRefreshDNS((void *) 1);
    if (0 == echo_hdr.opcode) {
	echo_hdr.opcode = ICP_SECHO;
	echo_hdr.version = ICP_VERSION_CURRENT;
	echo_hdr.length = 0;
	echo_hdr.reqnum = 0;
	echo_hdr.flags = 0;
	echo_hdr.pad = 0;
	echo_hdr.shostid = name.sin_addr.s_addr;
	sep = getservbyname("echo", "udp");
	echo_port = sep ? ntohs((u_short) sep->s_port) : 7;
    }
    first_ping = Config.peers;
    cachemgrRegister("server_list",
	"Peer Cache Statistics",
	neighborDumpPeers, 0, 1);
    cachemgrRegister("non_peers",
	"List of Unknown sites sending ICP messages",
	neighborDumpNonPeers, 0, 1);
}

int
neighborsUdpPing(request_t * request,
    StoreEntry * entry,
    IRCB * callback,
    void *callback_data,
    int *exprep,
    int *timeout)
{
    const char *url = storeUrl(entry);
    MemObject *mem = entry->mem_obj;
    peer *p = NULL;
    int i;
    int reqnum = 0;
    int flags;
    icp_common_t *query;
    int queries_sent = 0;
    int peers_pinged = 0;

    if (Config.peers == NULL)
	return 0;
    if (theOutIcpConnection < 0)
	fatal("neighborsUdpPing: There is no ICP socket!");
    assert(entry->swap_status == SWAPOUT_NONE);
    mem->start_ping = current_time;
    mem->ping_reply_callback = callback;
    mem->ircb_data = callback_data;
    *timeout = 0.0;
    reqnum = icpSetCacheKey(entry->key);
    for (i = 0, p = first_ping; i++ < Config.npeers; p = p->next) {
	if (p == NULL)
	    p = Config.peers;
	debug(15, 5) ("neighborsUdpPing: Peer %s\n", p->host);
	if (!peerWouldBePinged(p, request))
	    continue;		/* next peer */
	peers_pinged++;
	debug(15, 4) ("neighborsUdpPing: pinging peer %s for '%s'\n",
	    p->host, url);
	if (p->type == PEER_MULTICAST)
	    mcastSetTtl(theOutIcpConnection, p->mcast.ttl);
	debug(15, 3) ("neighborsUdpPing: key = '%s'\n", storeKeyText(entry->key));
	debug(15, 3) ("neighborsUdpPing: reqnum = %d\n", reqnum);

#if USE_HTCP
	if (p->options.htcp) {
	    debug(15, 3) ("neighborsUdpPing: sending HTCP query\n");
	    htcpQuery(entry, request, p);
	} else
#endif
	if (p->icp.port == echo_port) {
	    debug(15, 4) ("neighborsUdpPing: Looks like a dumb cache, send DECHO ping\n");
	    echo_hdr.reqnum = reqnum;
	    query = icpCreateMessage(ICP_DECHO, 0, url, reqnum, 0);
	    icpUdpSend(theOutIcpConnection,
		&p->in_addr,
		query,
		LOG_ICP_QUERY,
		0);
	} else {
	    flags = 0;
	    if (Config.onoff.query_icmp)
		if (p->icp.version == ICP_VERSION_2)
		    flags |= ICP_FLAG_SRC_RTT;
	    query = icpCreateMessage(ICP_QUERY, flags, url, reqnum, 0);
	    icpUdpSend(theOutIcpConnection,
		&p->in_addr,
		query,
		LOG_ICP_QUERY,
		0);
	}
	queries_sent++;

	p->stats.pings_sent++;
	if (p->type == PEER_MULTICAST) {
	    /*
	     * set a bogus last_reply time so neighborUp() never
	     * says a multicast peer is dead.
	     */
	    p->stats.last_reply = squid_curtime;
	    (*exprep) += p->mcast.n_replies_expected;
	} else if (squid_curtime - p->stats.last_query > Config.Timeout.deadPeer) {