
/*
 * $Id: neighbors.c,v 1.299.2.2 2002/08/28 04:41:16 wessels Exp $
 *
 * DEBUG: section 15    Neighbor Routines
 * AUTHOR: Harvest Derived
 *
 * SQUID Web Proxy Cache          http://www.squid-cache.org/
 * ----------------------------------------------------------
 *
 *  Squid is the result of efforts by numerous individuals from
 *  the Internet community; see the CONTRIBUTORS file for full
 *  details.   Many organizations have provided support for Squid's
 *  development; see the SPONSORS file for full details.  Squid is
 *  Copyrighted (C) 2001 by the Regents of the University of
 *  California; see the COPYRIGHT file for full details.  Squid
 *  incorporates software developed and/or copyrighted by other
 *  sources; 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 void peerProbeConnect(peer *);
static IPH peerProbeConnect2;
static CNCB peerProbeConnectDone;
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;

const 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 (0 == matchDomainName(request->host, d->domain))
           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 (0 == matchDomainName(request->host, d->domain)) {
           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;
    memset(&checklist, '\0', sizeof(checklist));
    checklist.src_addr = request->client_addr;
    checklist.my_addr = request->my_addr;
    checklist.my_port = request->my_port;
    checklist.request = request;
#if 0 && USE_IDENT
    /*
     * this is currently broken because 'request->user_ident' has been
     * moved to conn->rfc931 and we don't have access to the parent
     * ConnStateData here.
     */
    if (request->user_ident[0])
       xstrncpy(checklist.rfc931, request->user_ident, USER_IDENT_SZ);
#endif
    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;
    if (p->n_addresses == 0)
       return 0;
    if (p->icp.port == 0)
       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;
    /* Ping dead peers every timeout interval */
    if (squid_curtime - p->stats.last_query > Config.Timeout.deadPeer)
       return 1;
//2.6    if (p->icp.port == echo_port)
       if (!neighborUp(p))
          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;
    if (p->max_conn)
       if (p->stats.conn_open >= p->max_conn)
           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;
}

#if UNUSED_CODE
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;
}
#endif

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;
}


/* This gets called every 5 minutes to clear the round-robin counter. */
void
peerClearRR(void *data)
{
    peer *p = (peer *)data;
    p->rr_count -= p->rr_lastcount;
    if (p->rr_count < 0)
       p->rr_count = 0;
    p->rr_lastcount = p->rr_count;
    eventAdd("peerClearRR", peerClearRR, p, 5 * 60.0, 0);
}

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,peer);
       Config.npeers--;
    }
    first_ping = Config.peers;
}

void
neighbors_open(int fh)
{
    struct sockaddr_in name;
    socklen_t len = sizeof(struct sockaddr_in);
    struct servent *sep = NULL;
    const char *me = getMyHostname();
    peer *this_peer;
    peer *next;
    int socket;
    memset(&name, '\0', sizeof(struct sockaddr_in));
    socket = squid_fd_table.fd_table[fh].GetSocket();

    if (getsockname(socket, (struct sockaddr *) &name, &len) < 0)
       debug(15, 1) ("neighbors_open:getsockname(%d,%p,%p) failed.\n", socket, &name, &len);
    for (this_peer = Config.peers; this_peer; this_peer = next) {
       sockaddr_in_list *s;
       next = this_peer->next;
       if (0 != strcmp(this_peer->host, me))
           continue;
       for (s = Config.Sockaddr.http; s; s = s->next) {
           if (this_peer->http_port != ntohs(s->s.sin_port))
               continue;
           debug(15, 1) ("WARNING: Peer looks like this host\n");
           debug(15, 1) ("         Ignoring %s %s/%d/%d\n",
               neighborTypeStr(this_peer), this_peer->host, this_peer->http_port,
               this_peer->icp.port);
           neighborRemove(this_peer);
       }
    }

    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;
    int parent_timeout = 0, parent_exprep = 0;
    int sibling_timeout = 0, sibling_exprep = 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;
    reqnum = icpSetCacheKey((const cache_key*)entry->hash.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((const cache_key*)entry->hash.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 = (icp_common_t*)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 = (icp_common_t*)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 (neighborUp(p)) {
           /* its alive, expect a reply from it */
           if (neighborType(p, request) == PEER_PARENT) {
               parent_exprep++;
               parent_timeout += p->stats.rtt;
           } else {
               sibling_exprep++;
               sibling_timeout += p->stats.rtt;
           }
       } else {
           /* Neighbor is dead; ping it anyway, but don't expect a reply */
           /* log it once at the threshold */
           if (p->stats.logged_state == PEER_ALIVE) {
               debug(15, 1) ("Detected DEAD %s: %s/%d/%d\n",
                   neighborTypeStr(p),
                   p->host, p->http_port, p->icp.port);
               p->stats.logged_state = PEER_DEAD;
           }
       }
       p->stats.last_query = squid_curtime;
       if (p->stats.probe_start == 0)
           p->stats.probe_start = squid_curtime;
    }
    if ((first_ping = first_ping->next) == NULL)
       first_ping = Config.peers;

#if ALLOW_SOURCE_PING
    /* only do source_ping if we have neighbors */
    if (Config.npeers) {
       const ipcache_addrs *ia = NULL;
       struct sockaddr_in to_addr;
       char *host = request->host;
       if (!Config.onoff.source_ping) {
           debug(15, 6) ("neighborsUdpPing: Source Ping is disabled.\n");
       } else if ((ia = ipcache_gethostbyname(host, 0))) {
           debug(15, 6) ("neighborsUdpPing: Source Ping: to %s for '%s'\n",
               host, url);
           echo_hdr.reqnum = reqnum;
           if (icmp_sock_index != -1) {
               icmpSourcePing(ia->in_addrs[ia->cur], &echo_hdr, url);
           } else {
               to_addr.sin_family = AF_INET;
               to_addr.sin_addr = ia->in_addrs[ia->cur];
               to_addr.sin_port = htons(echo_port);
               query = icpCreateMessage(ICP_SECHO, 0, url, reqnum, 0);
               icpUdpSend(theOutIcpConnection,
                   &to_addr,
                   query,
                   LOG_ICP_QUERY,
                   0);
           }
       } else {
           debug(15, 6) ("neighborsUdpPing: Source Ping: unknown host: %s\n",
               host);
       }
    }
#endif
    /*
     * How many replies to expect?
     */
    *exprep = parent_exprep + sibling_exprep;

    /*
     * If there is a configured timeout, use it
     */
    if (Config.Timeout.icp_query)
       *timeout = Config.Timeout.icp_query;
    else {
       if (*exprep > 0) {
           if (parent_exprep)
               *timeout = 2 * parent_timeout / parent_exprep;
           else
               *timeout = 2 * sibling_timeout / sibling_exprep;
       } else
           *timeout = 2000;    /* 2 seconds */
       if (Config.Timeout.icp_query_max)
           if (*timeout > Config.Timeout.icp_query_max)
               *timeout = Config.Timeout.icp_query_max;
          if (*timeout < Config.Timeout.icp_query_min)
              *timeout = Config.Timeout.icp_query_min;
    }
    return peers_pinged;
}

/* lookup the digest of a given peer */
lookup_t
peerDigestLookup(peer * p, request_t * request)
{
#if USE_CACHE_DIGESTS
    const cache_key *key = request ? storeKeyPublicByRequest(request) : NULL;
    assert(p);
    assert(request);
    debug(15, 5) ("peerDigestLookup: peer %s\n", p->host);
    /* does the peeer have a valid digest? */
    if (!p->digest) {
       debug(15, 5) ("peerDigestLookup: gone!\n");
       return LOOKUP_NONE;
    } else if (!peerHTTPOkay(p, request)) {
       debug(15, 5) ("peerDigestLookup: !peerHTTPOkay\n");
       return LOOKUP_NONE;
    } else if (p->digest->flags.usable) {
       debug(15, 5) ("peerDigestLookup: usable\n");
       /* fall through; put here to have common case on top */ ;
    } else if (!p->digest->flags.needed) {
       debug(15, 5) ("peerDigestLookup: note need\n");
       peerDigestNeeded(p->digest);
       return LOOKUP_NONE;
    } else {
       debug(15, 5) ("peerDigestLookup: !ready && %srequested\n",
           p->digest->flags.requested ? "" : "!");
       return LOOKUP_NONE;
    }
    debug(15, 5) ("peerDigestLookup: OK to lookup peer %s\n", p->host);
    assert(p->digest->cd);
    /* does digest predict a hit? */
    if (!cacheDigestTest(p->digest->cd, key))
       return LOOKUP_MISS;
    debug(15, 5) ("peerDigestLookup: peer %s says HIT!\n", p->host);
    return LOOKUP_HIT;
#endif
    return LOOKUP_NONE;
}

/* select best peer based on cache digests */
peer *
neighborsDigestSelect(request_t * request)
{
    peer *best_p = NULL;
#if USE_CACHE_DIGESTS
    const cache_key *key;
    int best_rtt = 0;
    int choice_count = 0;
    int ichoice_count = 0;
    peer *p;
    int p_rtt;
    int i;
    if (!request->flags.hierarchical)
       return NULL;
    key = storeKeyPublicByRequest(request);
    for (i = 0, p = first_ping; i++ < Config.npeers; p = p->next) {
       lookup_t lookup;
       if (!p)
           p = Config.peers;
       if (i == 1)
           first_ping = p;
       lookup = peerDigestLookup(p, request);
       if (lookup == LOOKUP_NONE)
           continue;
       choice_count++;
       if (lookup == LOOKUP_MISS)
           continue;
       p_rtt = netdbHostRtt(p->host);
       debug(15, 5) ("neighborsDigestSelect: peer %s rtt: %d\n",
           p->host, p_rtt);
       /* is this peer better than others in terms of rtt ? */
       if (!best_p || (p_rtt && p_rtt < best_rtt)) {
           best_p = p;
           best_rtt = p_rtt;
           if (p_rtt)          /* informative choice (aka educated guess) */
               ichoice_count++;
           debug(15, 4) ("neighborsDigestSelect: peer %s leads with rtt %d\n",
               p->host, best_rtt);
       }
    }
    debug(15, 4) ("neighborsDigestSelect: choices: %d (%d)\n",
       choice_count, ichoice_count);
    peerNoteDigestLookup(request, best_p,
       best_p ? LOOKUP_HIT : (choice_count ? LOOKUP_MISS : LOOKUP_NONE));
    request->hier.n_choices = choice_count;
    request->hier.n_ichoices = ichoice_count;
#endif
    return best_p;
}

void
peerNoteDigestLookup(request_t * request, peer * p, lookup_t lookup)
{
#if USE_CACHE_DIGESTS
    if (p)
       strncpy(request->hier.cd_host, p->host, sizeof(request->hier.cd_host));
    else
       *request->hier.cd_host = '\0';
    request->hier.cd_lookup = lookup;
    debug(15, 4) ("peerNoteDigestLookup: peer %s, lookup: %s\n",
       p ? p->host : "<none>", lookup_t_str[lookup]);
#endif
}

static void
neighborAlive(peer * p, const MemObject * mem, const icp_common_t * header)
{
    if (p->stats.logged_state == PEER_DEAD && p->tcp_up) {
       debug(15, 1) ("Detected REVIVED %s: %s/%d/%d\n",
           neighborTypeStr(p),
           p->host, p->http_port, p->icp.port);
       p->stats.logged_state = PEER_ALIVE;
    }
    p->stats.last_reply = squid_curtime;
    p->stats.probe_start = 0;
    p->stats.pings_acked++;
    if ((icp_opcode) header->opcode <= ICP_END)
       p->icp.counts[header->opcode]++;
    p->icp.version = (int) header->version;
}

static void
neighborUpdateRtt(peer * p, MemObject * mem)
{
    int rtt,rtt_av_factor;
    if (!mem)
       return;
    if (!mem->start_ping.tv_sec)
       return;
    rtt = tvSubMsec(mem->start_ping, current_time);
    if (rtt < 1 || rtt > 10000)
       return;
    p->stats.rtt = intAverage(p->stats.rtt, rtt,
       p->stats.pings_acked, RTT_AV_FACTOR);
}

#if USE_HTCP
static void
neighborAliveHtcp(peer * p, const MemObject * mem, const htcpReplyData * htcp)
{
    if (p->stats.logged_state == PEER_DEAD && p->tcp_up) {
       debug(15, 1) ("Detected REVIVED %s: %s/%d/%d\n",
           neighborTypeStr(p),
           p->host, p->http_port, p->icp.port);
       p->stats.logged_state = PEER_ALIVE;
    }
    p->stats.last_reply = squid_curtime;
    p->stats.probe_start = 0;
    p->stats.pings_acked++;
    p->htcp.counts[htcp->hit ? 1 : 0]++;
    p->htcp.version = htcp->version;
}
#endif

static void
neighborCountIgnored(peer * p)
{
    if (p == NULL)
       return;
    p->stats.ignored_replies++;
    NLateReplies++;
}

static peer *non_peers = NULL;

static void
neighborIgnoreNonPeer(const struct sockaddr_in *from, icp_opcode opcode)
{
    peer *np;
    for (np = non_peers; np; np = np->next) {
       if (np->in_addr.sin_addr.s_addr != from->sin_addr.s_addr)
           continue;
       if (np->in_addr.sin_port != from->sin_port)
           continue;
       break;
    }
    if (np == NULL) {
       np = (peer *)xcalloc(1, sizeof(peer));
       np->in_addr.sin_addr = from->sin_addr;
       np->in_addr.sin_port = from->sin_port;
       np->icp.port = ntohl(from->sin_port);
       np->type = PEER_NONE;
       np->host = xstrdup(inet_ntoa(from->sin_addr));
       np->next = non_peers;
       non_peers = np;
    }
    np->icp.counts[opcode]++;
    if (isPowTen(++np->stats.ignored_replies))
       debug(15, 1) ("WARNING: Ignored %d replies from non-peer %s\n",
           np->stats.ignored_replies, np->host);
}

/* ignoreMulticastReply
 *
 * * We want to ignore replies from multicast peers if the
 * * cache_host_domain rules would normally prevent the peer
 * * from being used
 */
static int
ignoreMulticastReply(peer * p, MemObject * mem)
{
    if (p == NULL)
       return 0;
    if (!p->options.mcast_responder)
       return 0;
    if (peerHTTPOkay(p, mem->request))
       return 0;
    return 1;
}

/* I should attach these records to the entry.  We take the first
 * hit we get our wait until everyone misses.  The timeout handler
 * call needs to nip this shopping list or call one of the misses.
 *
 * If a hit process is already started, then sobeit
 */
void
neighborsUdpAck(const cache_key * key, icp_common_t * header, const struct sockaddr_in *from)
{
    peer *p = NULL;
    StoreEntry *entry;
    MemObject *mem = NULL;
    peer_t ntype = PEER_NONE;
    char *opcode_d;
    icp_opcode opcode = (icp_opcode) header->opcode;

    debug(15, 6) ("neighborsUdpAck: opcode %d '%s'\n",
       (int) opcode, storeKeyText(key));
    if (NULL != (entry = storeGet(key)))
       mem = entry->mem_obj;
    p = whichPeer(from);
    if (p)
       neighborAlive(p, mem, header);
    if (opcode > ICP_END)
       return;
    opcode_d = icp_opcode_str[opcode];
    if (p)
       neighborUpdateRtt(p, mem);
    /* Does the entry exist? */
    if (NULL == entry) {
       debug(12, 3) ("neighborsUdpAck: Cache key '%s' not found\n",
           storeKeyText(key));
       neighborCountIgnored(p);
       return;
    }
    /* check if someone is already fetching it */
    if (EBIT_TEST(entry->flags, ENTRY_DISPATCHED)) {
       debug(15, 3) ("neighborsUdpAck: '%s' already being fetched.\n",
           storeKeyText(key));
       neighborCountIgnored(p);
       return;
    }
    if (mem == NULL) {
       debug(15, 2) ("Ignoring %s for missing mem_obj: %s\n",
           opcode_d, storeKeyText(key));
       neighborCountIgnored(p);
       return;
    }
    if (entry->ping_status != PING_WAITING) {
       debug(15, 2) ("neighborsUdpAck: Late %s for %s\n",
           opcode_d, storeKeyText(key));
       neighborCountIgnored(p);
       return;
    }
    if (entry->lock_count == 0) {
       debug(12, 1) ("neighborsUdpAck: '%s' has no locks\n",
           storeKeyText(key));
       neighborCountIgnored(p);
       return;
    }
    debug(15, 3) ("neighborsUdpAck: %s for '%s' from %s \n",
       opcode_d, storeKeyText(key), p ? p->host : "source");
    if (p) {
       ntype = neighborType(p, mem->request);
    }
    if (ignoreMulticastReply(p, mem)) {
       neighborCountIgnored(p);
    } else if (opcode == ICP_MISS) {
       if (p == NULL) {
           neighborIgnoreNonPeer(from, opcode);
       } else {
           mem->ping_reply_callback(p, ntype, PROTO_ICP, header, mem->ircb_data);
       }
    } else if (opcode == ICP_HIT) {
       if (p == NULL) {
           neighborIgnoreNonPeer(from, opcode);
       } else {
           header->opcode = ICP_HIT;
           mem->ping_reply_callback(p, ntype, PROTO_ICP, header, mem->ircb_data);
       }
    } else if (opcode == ICP_DECHO) {
       if (p == NULL) {
           neighborIgnoreNonPeer(from, opcode);
       } else if (ntype == PEER_SIBLING) {
           debug_trap("neighborsUdpAck: Found non-ICP cache as SIBLING\n");
           debug_trap("neighborsUdpAck: non-ICP neighbors must be a PARENT\n");
       } else {
           mem->ping_reply_callback(p, ntype, PROTO_ICP, header, mem->ircb_data);
       }
    } else if (opcode == ICP_SECHO) {
       if (p) {
           debug(15, 1) ("Ignoring SECHO from neighbor %s\n", p->host);
           neighborCountIgnored(p);
#if ALLOW_SOURCE_PING
       } else if (Config.onoff.source_ping) {
           mem->ping_reply_callback(NULL, ntype, PROTO_ICP, header, mem->ircb_data);
#endif
       } else {
           debug(15, 1) ("Unsolicited SECHO from %s\n", inet_ntoa(from->sin_addr));
       }
    } else if (opcode == ICP_DENIED) {
       if (p == NULL) {
           neighborIgnoreNonPeer(from, opcode);
       } else if (p->stats.pings_acked > 100) {
           if (100 * p->icp.counts[ICP_DENIED] / p->stats.pings_acked > 95) {
               debug(15, 0) ("95%% of replies from '%s' are UDP_DENIED\n", p->host);
               debug(15, 0) ("Disabling '%s', please check your configuration.\n", p->host);
               neighborRemove(p);
               p = NULL;
           } else {
               neighborCountIgnored(p);
           }
       }
    } else if (opcode == ICP_MISS_NOFETCH) {
       mem->ping_reply_callback(p, ntype, PROTO_ICP, header, mem->ircb_data);
    } else {
       debug(15, 0) ("neighborsUdpAck: Unexpected ICP reply: %s\n", opcode_d);
    }
}

peer *
peerFindByName(const char *name)
{
    peer *p = NULL;
    for (p = Config.peers; p; p = p->next) {
       if (!strcasecmp(name, p->host))
           break;
    }
    return p;
}

peer *
peerFindByNameAndPort(const char *name, unsigned short port)
{
    peer *p = NULL;
    for (p = Config.peers; p; p = p->next) {
       if (strcasecmp(name, p->host))
           continue;
       if (port != p->http_port)
           continue;
       break;
    }
    return p;
}

int
neighborUp(const peer * p)
{
    if (!p->tcp_up) {
       peerProbeConnect((peer *) p);
       return 0;
    }
    if (p->options.no_query)
       return 1;
    if (p->stats.probe_start != 0 &&
       squid_curtime - p->stats.probe_start > Config.Timeout.deadPeer)
       return 0;
    /*
     * The peer can not be UP if we don't have any IP addresses
     * for it.
     */
    if (0 == p->n_addresses)
       return 0;
    return 1;
}

void
peerDestroy(void *data)
{
    peer *p = ( peer *)data;
    struct _domain_ping *l = NULL;
    struct _domain_ping *nl = NULL;
    if (p == NULL)
       return;
    for (l = p->peer_domain; l; l = nl) {
       nl = l->next;
       safe_free(l->domain);
       safe_free(l);
    }
    safe_free(p->host);
#if USE_CACHE_DIGESTS
    if (p->digest) {
       PeerDigest *pd = p->digest;
       p->digest = NULL;
       cbdataUnlock(pd);
    }

#endif
}

void
peerNoteDigestGone(peer * p)
{
#if USE_CACHE_DIGESTS
    if (p->digest) {
       PeerDigest *pd = p->digest;
       p->digest = NULL;
       cbdataUnlock(pd);
    }
#endif
}

static void
peerDNSConfigure(const ipcache_addrs * ia, void *data)
{
    peer *p = (peer *)data;
    struct sockaddr_in *ap;
    int j;
    if (p->n_addresses == 0) {
       debug(15, 1) ("Configuring %s %s/%d/%d\n", neighborTypeStr(p),
           p->host, p->http_port, p->icp.port);
       if (p->type == PEER_MULTICAST)
           debug(15, 1) ("    Multicast TTL = %d\n", p->mcast.ttl);
    }
    p->n_addresses = 0;
    if (ia == NULL) {
       debug(0, 0) ("WARNING: DNS lookup for '%s' failed!\n", p->host);
       return;
    }
    if ((int) ia->count < 1) {
       debug(0, 0) ("WARNING: No IP address found for '%s'!\n", p->host);
       return;
    }
    for (j = 0; j < (int) ia->count && j < PEER_MAX_ADDRESSES; j++) {
       p->addresses[j] = ia->in_addrs[j];
       debug(15, 2) ("--> IP address #%d: %s\n", j, inet_ntoa(p->addresses[j]));
       p->n_addresses++;
    }
    ap = &p->in_addr;
    memset(ap, '\0', sizeof(struct sockaddr_in));
    ap->sin_family = AF_INET;
    ap->sin_addr = p->addresses[0];
    ap->sin_port = htons(p->icp.port);
    if (p->type == PEER_MULTICAST)
       peerCountMcastPeersSchedule(p, 10);
    if (p->type != PEER_MULTICAST)
       if (!p->options.no_netdb_exchange)
           eventAddIsh("netdbExchangeStart", netdbExchangeStart, p, 30.0, 1);
}

static void
peerRefreshDNS(void *data)
{
    peer *p = NULL;
    if (eventFind(peerRefreshDNS, NULL))
       eventDelete(peerRefreshDNS, NULL);
    if (!data && 0 == stat5minClientRequests()) {
       /* no recent client traffic, wait a bit */
       eventAddIsh("peerRefreshDNS", peerRefreshDNS, NULL, 180.0, 1);
       return;
    }
    for (p = Config.peers; p; p = p->next)
       ipcache_nbgethostbyname(p->host, peerDNSConfigure, p);
    /* Reconfigure the peers every hour */
    eventAddIsh("peerRefreshDNS", peerRefreshDNS, NULL, 3600.0, 1);
}

void
peerConnectFailed(peer * p)
{
    p->stats.last_connect_failure = squid_curtime;
    if (!p->tcp_up) {
       debug(15, 2) ("TCP connection to %s/%d dead\n", p->host, p->http_port);
       return;
    }
    debug(15, 1) ("TCP connection to %s/%d failed\n", p->host, p->http_port);
    p->tcp_up--;
    if (!p->tcp_up) {
       debug(15, 1) ("Detected DEAD %s: %s/%d/%d\n",
           neighborTypeStr(p),
           p->host, p->http_port, p->icp.port);
       p->stats.logged_state = PEER_DEAD;
    }
}

void
peerConnectSucceded(peer * p)
{
    if (!p->tcp_up) {
       debug(15, 2) ("TCP connection to %s/%d succeded\n", p->host, p->http_port);
       debug(15, 1) ("Detected REVIVED %s: %s/%d/%d\n",
           neighborTypeStr(p),
           p->host, p->http_port, p->icp.port);
       p->stats.logged_state = PEER_ALIVE;
    }
    p->tcp_up = PEER_TCP_MAGIC_COUNT;
}

/*
 * peerProbeConnect will be called on dead peers by neighborUp
 */
static void
peerProbeConnect(peer * p)
{
    int fd;
    if (p->test_fd != -1)
       return;                 /* probe already running */
    if (squid_curtime - p->stats.last_connect_probe < Config.Timeout.connect)
       return;                 /* don't probe to often */
    fd = comm_open(SOCK_STREAM, 0, getOutgoingAddr(NULL),
       0, COMM_NONBLOCKING, p->host);
    if (fd < 0)
       return;
    p->test_fd = fd;
    p->stats.last_connect_probe = squid_curtime;
    ipcache_nbgethostbyname(p->host, peerProbeConnect2, p);
}

static void
peerProbeConnect2(const ipcache_addrs * ianotused, void *data)
{
    peer *p = ( peer *)data;
    commConnectStart(p->test_fd,
       p->host,
       p->http_port,
       peerProbeConnectDone,
       p);
}

static void
peerProbeConnectDone(int fd, int status, void *data)
{
    peer *p = (peer *)data;
    if (status == COMM_OK) {
       peerConnectSucceded(p);
    } else {
       peerConnectFailed(p);
    }
    comm_close(fd);
    p->test_fd = -1;
    return;
}

static void
peerCountMcastPeersSchedule(peer * p, time_t when)
{
    if (p->mcast.flags.count_event_pending)
       return;
    eventAdd("peerCountMcastPeersStart",
       peerCountMcastPeersStart,
       p,
       (double) when, 1);
    p->mcast.flags.count_event_pending = 1;
}

static void
peerCountMcastPeersStart(void *data)
{
    peer *p = (peer *)data;
    ps_state *psstate;
    StoreEntry *fake;
    MemObject *mem;
    icp_common_t *query;
    int reqnum;
    LOCAL_ARRAY(char, url, MAX_URL);
    assert(p->type == PEER_MULTICAST);
    p->mcast.flags.count_event_pending = 0;
    snprintf(url, MAX_URL, "http://%s/", inet_ntoa(p->in_addr.sin_addr));
    fake = storeCreateEntry(url, url, null_request_flags, METHOD_GET);
    psstate = cbdataAlloc(ps_state);
    psstate->request = requestLink(urlParse(METHOD_GET, url));
    psstate->entry = fake;
    psstate->callback = NULL;
    psstate->callback_data = p;
    psstate->ping.start = current_time;
    mem = fake->mem_obj;
    mem->request = requestLink(psstate->request);
    mem->start_ping = current_time;
    mem->ping_reply_callback = peerCountHandleIcpReply;
    mem->ircb_data = psstate;
    mcastSetTtl(theOutIcpConnection, p->mcast.ttl);
    p->mcast.id = mem->id;
    reqnum = icpSetCacheKey((const cache_key*)fake->hash.key);
    query = (icp_common_t*)icpCreateMessage(ICP_QUERY, 0, url, reqnum, 0);
    icpUdpSend(theOutIcpConnection,
       &p->in_addr,
       query,
       LOG_ICP_QUERY,
       0);
    fake->ping_status = PING_WAITING;
    eventAdd("peerCountMcastPeersDone",
       peerCountMcastPeersDone,
       psstate,
       (double) Config.Timeout.mcast_icp_query, 1);
    p->mcast.flags.counting = 1;
    peerCountMcastPeersSchedule(p, MCAST_COUNT_RATE);
}

static void
peerCountMcastPeersDone(void *data)
{
    ps_state *psstate = (ps_state*)data;
    peer *p = ( peer *)psstate->callback_data;
    StoreEntry *fake = psstate->entry;
    p->mcast.flags.counting = 0;
    p->mcast.avg_n_members = doubleAverage(p->mcast.avg_n_members,
       (double) psstate->ping.n_recv,
       ++p->mcast.n_times_counted,
       10);
    debug(15, 1) ("Group %s: %d replies, %4.1f average, RTT %d\n",
       p->host,
       psstate->ping.n_recv,
       p->mcast.avg_n_members,
       p->stats.rtt);
    p->mcast.n_replies_expected = (int) p->mcast.avg_n_members;
    EBIT_SET(fake->flags, ENTRY_ABORTED);
    requestUnlink(fake->mem_obj->request);
    fake->mem_obj->request = NULL;
    storeReleaseRequest(fake);
    storeUnlockObject(fake);
    requestUnlink(psstate->request);
    cbdataFree(psstate,ps_state);
}

static void
peerCountHandleIcpReply(peer * p, peer_t type, protocol_t proto, void *hdrnotused, void *data)
{   int rtt_av_factor;
    ps_state *psstate = (ps_state *)data;
    StoreEntry *fake = psstate->entry;
    MemObject *mem = fake->mem_obj;
    int rtt = tvSubMsec(mem->start_ping, current_time);
    assert(proto == PROTO_ICP);
    assert(fake);
    assert(mem);
    psstate->ping.n_recv++;
    p->stats.rtt = intAverage(p->stats.rtt, rtt, psstate->ping.n_recv, RTT_AV_FACTOR);
}

static void
neighborDumpPeers(StoreEntry * sentry)
{
    dump_peers(sentry, Config.peers);
}

static void
neighborDumpNonPeers(StoreEntry * sentry)
{
    dump_peers(sentry, non_peers);
}

void
dump_peer_options(StoreEntry * sentry, peer * p)
{
    if (p->options.proxy_only)
       storeAppendPrintf(sentry, " proxy-only");
    if (p->options.no_query)
       storeAppendPrintf(sentry, " no-query");
    if (p->options.no_digest)
       storeAppendPrintf(sentry, " no-digest");
    if (p->options.default_parent)
       storeAppendPrintf(sentry, " default");
    if (p->options.roundrobin)
       storeAppendPrintf(sentry, " round-robin");
    if (p->options.mcast_responder)
       storeAppendPrintf(sentry, " multicast-responder");
    if (p->options.closest_only)
       storeAppendPrintf(sentry, " closest-only");
#if USE_HTCP
    if (p->options.htcp)
       storeAppendPrintf(sentry, " htcp");
#endif
    if (p->options.no_netdb_exchange)
       storeAppendPrintf(sentry, " no-netdb-exchange");
#if DELAY_POOLS
    if (p->options.no_delay)
       storeAppendPrintf(sentry, " no-delay");
#endif
    if (p->login)
       storeAppendPrintf(sentry, " login=%s", p->login);
    if (p->mcast.ttl > 0)
       storeAppendPrintf(sentry, " ttl=%d", p->mcast.ttl);
    storeAppendPrintf(sentry, "\n");
}

static void
dump_peers(StoreEntry * sentry, peer * peers)
{
    peer *e = NULL;
    struct _domain_ping *d = NULL;
//EK    icp_opcode op;
    int op;
    int i;
    if (peers == NULL)
       storeAppendPrintf(sentry, "There are no neighbors installed.\n");
    for (e = peers; e; e = e->next) {
       assert(e->host != NULL);
       storeAppendPrintf(sentry, "\n%-11.11s: %s/%d/%d\n",
           neighborTypeStr(e),
           e->host,
           e->http_port,
           e->icp.port);
       storeAppendPrintf(sentry, "Flags      :");
       dump_peer_options(sentry, e);
       for (i = 0; i < e->n_addresses; i++) {
           storeAppendPrintf(sentry, "Address[%d] : %s\n", i,
               inet_ntoa(e->addresses[i]));
       }
       storeAppendPrintf(sentry, "Status     : %s\n",
           neighborUp(e) ? "Up" : "Down");
       storeAppendPrintf(sentry, "AVG RTT    : %d msec\n", e->stats.rtt);
       storeAppendPrintf(sentry, "OPEN CONNS : %d\n", e->stats.conn_open);
       storeAppendPrintf(sentry, "LAST QUERY : %8d seconds ago\n",
           (int) (squid_curtime - e->stats.last_query));
       storeAppendPrintf(sentry, "LAST REPLY : %8d seconds ago\n",
           (int) (squid_curtime - e->stats.last_reply));
       storeAppendPrintf(sentry, "PINGS SENT : %8d\n", e->stats.pings_sent);
       storeAppendPrintf(sentry, "PINGS ACKED: %8d %3d%%\n",
           e->stats.pings_acked,
           percent(e->stats.pings_acked, e->stats.pings_sent));
       storeAppendPrintf(sentry, "FETCHES    : %8d %3d%%\n",
           e->stats.fetches,
           percent(e->stats.fetches, e->stats.pings_acked));
       storeAppendPrintf(sentry, "IGNORED    : %8d %3d%%\n",
           e->stats.ignored_replies,
           percent(e->stats.ignored_replies, e->stats.pings_acked));
       storeAppendPrintf(sentry, "Histogram of PINGS ACKED:\n");
#if USE_HTCP
       if (e->options.htcp) {
           storeAppendPrintf(sentry, "\tMisses\t%8d %3d%%\n",
               e->htcp.counts[0],
               percent(e->htcp.counts[0], e->stats.pings_acked));
           storeAppendPrintf(sentry, "\tHits\t%8d %3d%%\n",
               e->htcp.counts[1],
               percent(e->htcp.counts[1], e->stats.pings_acked));
       } else {
#endif
           for (op = ICP_INVALID; op < ICP_END; op++) {
               if (e->icp.counts[op] == 0)
                   continue;
               storeAppendPrintf(sentry, "    %12.12s : %8d %3d%%\n",
                   icp_opcode_str[op],
                   e->icp.counts[op],
                   percent(e->icp.counts[op], e->stats.pings_acked));
           }
#if USE_HTCP
       }
#endif
       if (e->stats.last_connect_failure) {
           storeAppendPrintf(sentry, "Last failed connect() at: %s\n",
               mkhttpdlogtime(&(e->stats.last_connect_failure)));
       }
       if (e->peer_domain != NULL) {
           storeAppendPrintf(sentry, "DOMAIN LIST: ");
           for (d = e->peer_domain; d; d = d->next) {
               storeAppendPrintf(sentry, "%s%s ",
                   d->do_ping ? null_string : "!", d->domain);
           }
           storeAppendPrintf(sentry, "\n");
       }
       storeAppendPrintf(sentry, "keep-alive ratio: %d%%\n",
           percent(e->stats.n_keepalives_recv, e->stats.n_keepalives_sent));
    }
}

#if USE_HTCP
void
neighborsHtcpReply(const cache_key * key, htcpReplyData * htcp, const struct sockaddr_in *from)
{
    StoreEntry *e = storeGet(key);
    MemObject *mem = NULL;
    peer *p;
    peer_t ntype = PEER_NONE;
    debug(15, 6) ("neighborsHtcpReply: %s %s\n",
       htcp->hit ? "HIT" : "MISS", storeKeyText(key));
    if (NULL != (e = storeGet(key)))
       mem = e->mem_obj;
    if ((p = whichPeer(from)))
       neighborAliveHtcp(p, mem, htcp);
    /* Does the entry exist? */
    if (NULL == e) {
       debug(12, 3) ("neighyborsHtcpReply: Cache key '%s' not found\n",
           storeKeyText(key));
       neighborCountIgnored(p);
       return;
    }
    /* check if someone is already fetching it */
    if (EBIT_TEST(e->flags, ENTRY_DISPATCHED)) {
       debug(15, 3) ("neighborsUdpAck: '%s' already being fetched.\n",
           storeKeyText(key));
       neighborCountIgnored(p);
       return;
    }
    if (mem == NULL) {
       debug(15, 2) ("Ignoring reply for missing mem_obj: %s\n",
           storeKeyText(key));
       neighborCountIgnored(p);
       return;
    }
    if (e->ping_status != PING_WAITING) {
       debug(15, 2) ("neighborsUdpAck: Entry %s is not PING_WAITING\n",
           storeKeyText(key));
       neighborCountIgnored(p);
       return;
    }
    if (e->lock_count == 0) {
       debug(12, 1) ("neighborsUdpAck: '%s' has no locks\n",
           storeKeyText(key));
       neighborCountIgnored(p);
       return;
    }
    if (p) {
       ntype = neighborType(p, mem->request);
       neighborUpdateRtt(p, mem);
    }
    if (ignoreMulticastReply(p, mem)) {
       neighborCountIgnored(p);
       return;
    }
    debug(15, 3) ("neighborsHtcpReply: e = %p\n", e);
    mem->ping_reply_callback(p, ntype, PROTO_HTCP, htcp, mem->ircb_data);
}
#endif
