net_db.c

-

/*
 * $Id: net_db.c,v 1.136.2.1 1999/03/22 03:21:54 wessels Exp $
 *
 * DEBUG: section 38    Network Measurement Database
 * 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"

#if USE_ICMP

typedef struct {
    peer *p;
    StoreEntry *e;
    request_t *r;
    off_t seen;
    off_t used;
    size_t buf_sz;
    char *buf;
} netdbExchangeState;

static hash_table *addr_table = NULL;
static hash_table *host_table = NULL;

static struct in_addr networkFromInaddr(struct in_addr a);
static void netdbRelease(netdbEntry * n);
static void netdbHashInsert(netdbEntry * n, struct in_addr addr);
static void netdbHashDelete(const char *key);
static void netdbHostInsert(netdbEntry * n, const char *hostname);
static void netdbHostDelete(const net_db_name * x);
static void netdbPurgeLRU(void);
static netdbEntry *netdbLookupHost(const char *key);
static net_db_peer *netdbPeerByName(const netdbEntry * n, const char *);
static net_db_peer *netdbPeerAdd(netdbEntry * n, peer * e);
static char *netdbPeerName(const char *name);
static IPH netdbSendPing;
static QS sortPeerByRtt;
static QS sortByRtt;
static QS netdbLRU;
static FREE netdbFreeNameEntry;
static FREE netdbFreeNetdbEntry;
static STCB netdbExchangeHandleReply;
static void netdbExchangeDone(void *);

/* We have to keep a local list of peer names.  The Peers structure
 * gets freed during a reconfigure.  We want this database to
 * remain persisitent, so _net_db_peer->peername points into this
 * linked list */
static wordlist *peer_names = NULL;

static void
netdbHashInsert(netdbEntry * n, struct in_addr addr)
{
    xstrncpy(n->network, inet_ntoa(networkFromInaddr(addr)), 16);
    n->key = n->network;
    assert(hash_lookup(addr_table, n->network) == NULL);
    hash_join(addr_table, (hash_link *) n);
}

static void
netdbHashDelete(const char *key)
{
    hash_link *hptr = hash_lookup(addr_table, key);
    if (hptr == NULL) {
	debug_trap("netdbHashDelete: key not found");
	return;
    }
    hash_remove_link(addr_table, hptr);
}

static void
netdbHostInsert(netdbEntry * n, const char *hostname)
{
    net_db_name *x = memAllocate(MEM_NET_DB_NAME);
    x->name = xstrdup(hostname);
    x->next = n->hosts;
    n->hosts = x;
    x->net_db_entry = n;
    assert(hash_lookup(host_table, hostname) == NULL);
    hash_join(host_table, (hash_link *) x);
    n->link_count++;
}

static void
netdbHostDelete(const net_db_name * x)
{
    netdbEntry *n;
    net_db_name **X;
    assert(x != NULL);
    assert(x->net_db_entry != NULL);
    n = x->net_db_entry;
    n->link_count--;
    for (X = &n->hosts; *X; X = &(*X)->next) {
	if (*X == x) {
	    *X = x->next;
	    break;
	}
    }
    hash_remove_link(host_table, (hash_link *) x);
    xfree(x->name);
    memFree((void *) x, MEM_NET_DB_NAME);
}

static netdbEntry *
netdbLookupHost(const char *key)
{
    net_db_name *x = (net_db_name *) hash_lookup(host_table, key);
    return x ? x->net_db_entry : NULL;
}

static void
netdbRelease(netdbEntry * n)
{
    net_db_name *x;
    net_db_name *next;
    for (x = n->hosts; x; x = next) {
	next = x->next;
	netdbHostDelete(x);
    }
    n->hosts = NULL;
    safe_free(n->peers);
    n->peers = NULL;
    n->n_peers = 0;
    n->n_peers_alloc = 0;
    if (n->link_count == 0) {
	netdbHashDelete(n->network);
	memFree(n, MEM_NETDBENTRY);
    }
}

static int
netdbLRU(const void *A, const void *B)
{
    const netdbEntry *const *n1 = A;
    const netdbEntry *const *n2 = B;
    if ((*n1)->last_use_time > (*n2)->last_use_time)
	return (1);
    if ((*n1)->last_use_time < (*n2)->last_use_time)
	return (-1);
    return (0);
}

static void
netdbPurgeLRU(void)
{
    netdbEntry *n;
    netdbEntry **list;
    int k = 0;
    int list_count = 0;
    int removed = 0;
    list = xcalloc(memInUse(MEM_NETDBENTRY), sizeof(netdbEntry *));
    hash_first(addr_table);
    while ((n = (netdbEntry *) hash_next(addr_table))) {
	assert(list_count < memInUse(MEM_NETDBENTRY));
	*(list + list_count) = n;
	list_count++;
    }
    qsort((char *) list,
	list_count,
	sizeof(netdbEntry *),
	netdbLRU);
    for (k = 0; k < list_count; k++) {
	if (memInUse(MEM_NETDBENTRY) < Config.Netdb.low)
	    break;
	netdbRelease(*(list + k));
	removed++;
    }
    xfree(list);
}

static netdbEntry *
netdbLookupAddr(struct in_addr addr)
{
    netdbEntry *n;
    char *key = inet_ntoa(networkFromInaddr(addr));
    n = (netdbEntry *) hash_lookup(addr_table, key);
    return n;
}

static netdbEntry *
netdbAdd(struct in_addr addr)
{
    netdbEntry *n;
    if (memInUse(MEM_NETDBENTRY) > Config.Netdb.high)
	netdbPurgeLRU();
    if ((n = netdbLookupAddr(addr)) == NULL) {
	n = memAllocate(MEM_NETDBENTRY);
	netdbHashInsert(n, addr);
    }
    return n;
}

static void
netdbSendPing(const ipcache_addrs * ia, void *data)
{
    struct in_addr addr;
    char *hostname = data;
    netdbEntry *n;
    netdbEntry *na;
    net_db_name *x;
    net_db_name **X;
    cbdataUnlock(hostname);
    if (ia == NULL) {
	cbdataFree(hostname);
	return;
    }
    addr = ia->in_addrs[ia->cur];
    if ((n = netdbLookupHost(hostname)) == NULL) {
	n = netdbAdd(addr);
	netdbHostInsert(n, hostname);
    } else if ((na = netdbLookupAddr(addr)) != n) {
	/*
	 *hostname moved from 'network n' to 'network na'!
	 */
	if (na == NULL)
	    na = netdbAdd(addr);
	debug(38, 3) ("netdbSendPing: %s moved from %s to %s\n",
	    hostname, n->network, na->network);
	x = (net_db_name *) hash_lookup(host_table, hostname);
	if (x == NULL) {
	    debug(38, 1) ("netdbSendPing: net_db_name list bug: %s not found", hostname);
	    cbdataFree(hostname);
	    return;
	}
	/* remove net_db_name from 'network n' linked list */
	for (X = &n->hosts; *X; X = &(*X)->next) {
	    if (*X == x) {
		*X = x->next;
		break;
	    }
	}
	n->link_count--;
	/* point to 'network na' from host entry */
	x->net_db_entry = na;
	/* link net_db_name to 'network na' */
	x->next = na->hosts;
	na->hosts = x;
	na->link_count++;
	n = na;
    }
    if (n->next_ping_time <= squid_curtime) {
	debug(38, 3) ("netdbSendPing: pinging %s\n", hostname);
	icmpDomainPing(addr, hostname);
	n->pings_sent++;
	n->next_ping_time = squid_curtime + Config.Netdb.period;
	n->last_use_time = squid_curtime;
    }
    cbdataFree(hostname);
}

static struct in_addr
networkFromInaddr(struct in_addr a)
{
    struct in_addr b;
    b.s_addr = ntohl(a.s_addr);
#if USE_CLASSFUL
    if (IN_CLASSC(b.s_addr))
	b.s_addr &= IN_CLASSC_NET;
    else if (IN_CLASSB(b.s_addr))
	b.s_addr &= IN_CLASSB_NET;
    else if (IN_CLASSA(b.s_addr))
	b.s_addr &= IN_CLASSA_NET;
#else
    /* use /24 for everything */
    b.s_addr &= IN_CLASSC_NET;
#endif
    b.s_addr = htonl(b.s_addr);
    return b;
}

static int
sortByRtt(const void *A, const void *B)
{
    const netdbEntry *const *n1 = A;
    const netdbEntry *const *n2 = B;
    if ((*n1)->rtt > (*n2)->rtt)
	return 1;
    else if ((*n1)->rtt < (*n2)->rtt)
	return -1;
    else
	return 0;
}

static net_db_peer *
netdbPeerByName(const netdbEntry * n, const char *peername)
{
    int i;
    net_db_peer *p = n->peers;
    for (i = 0; i < n->n_peers; i++, p++) {
	if (!strcmp(p->peername, peername))
	    return p;
    }
    return NULL;
}

static net_db_peer *
netdbPeerAdd(netdbEntry * n, peer * e)
{
    net_db_peer *p;
    net_db_peer *o;
    int osize;
    int i;
    if (n->n_peers == n->n_peers_alloc) {
	o = n->peers;
	osize = n->n_peers_alloc;
	if (n->n_peers_alloc == 0)
	    n->n_peers_alloc = 2;
	else
	    n->n_peers_alloc <<= 1;
	debug(38, 3) ("netdbPeerAdd: Growing peer list for '%s' to %d\n",
	    n->network, n->n_peers_alloc);
	n->peers = xcalloc(n->n_peers_alloc, sizeof(net_db_peer));
	for (i = 0; i < osize; i++)
	    *(n->peers + i) = *(o + i);
	if (osize) {
	    safe_free(o);
	}
    }
    p = n->peers + n->n_peers;
    p->peername = netdbPeerName(e->host);
    n->n_peers++;
    return p;
}

static int
sortPeerByRtt(const void *A, const void *B)
{
    const net_db_peer *p1 = A;
    const net_db_peer *p2 = B;
    if (p1->rtt > p2->rtt)
	return 1;
    else if (p1->rtt < p2->rtt)
	return -1;
    else
	return 0;
}

static void
netdbSaveState(void *foo)
{
    LOCAL_ARRAY(char, path, SQUID_MAXPATHLEN);
    FILE *fp;
    netdbEntry *n;
    net_db_name *x;
    struct timeval start = current_time;
    int count = 0;
    snprintf(path, SQUID_MAXPATHLEN, "%s/netdb_state", storeSwapDir(0));
    fp = fopen(path, "w");
    if (fp == NULL) {
	debug(50, 1) ("netdbSaveState: %s: %s\n", path, xstrerror());
	return;
    }
    hash_first(addr_table);
    while ((n = (netdbEntry *) hash_next(addr_table))) {
	if (n->pings_recv == 0)
	    continue;
	fprintf(fp, "%s %d %d %10.5f %10.5f %d %d",
	    n->network,
	    n->pings_sent,
	    n->pings_recv,
	    n->hops,
	    n->rtt,
	    (int) n->next_ping_time,
	    (int) n->last_use_time);
	for (x = n->hosts; x; x = x->next)
	    fprintf(fp, " %s", x->name);
	fprintf(fp, "\n");
	count++;
    }
    fclose(fp);
    getCurrentTime();
    debug(38, 1) ("NETDB state saved; %d entries, %d msec\n",
	count, tvSubMsec(start, current_time));
    eventAddIsh("netdbSaveState", netdbSaveState, NULL, 3600.0, 1);
}

static void
netdbReloadState(void)
{
    LOCAL_ARRAY(char, path, SQUID_MAXPATHLEN);
    char *buf;
    char *t;
    FILE *fp;
    netdbEntry *n;
    netdbEntry N;
    struct in_addr addr;
    int count = 0;
    struct timeval start = current_time;
    snprintf(path, SQUID_MAXPATHLEN, "%s/netdb_state", storeSwapDir(0));
    fp = fopen(path, "r");
    if (fp == NULL)
	return;
    buf = memAllocate(MEM_4K_BUF);
    while (fgets(buf, 4095, fp)) {
	memset(&N, '\0', sizeof(netdbEntry));
	if ((t = strtok(buf, w_space)) == NULL)
	    continue;
	if (!safe_inet_addr(t, &addr))
	    continue;
	if (netdbLookupAddr(addr) != NULL)	/* no dups! */
	    continue;
	if ((t = strtok(NULL, w_space)) == NULL)
	    continue;
	N.pings_sent = atoi(t);
	if ((t = strtok(NULL, w_space)) == NULL)
	    continue;
	N.pings_recv = atoi(t);
	if (N.pings_recv == 0)
	    continue;
	/* give this measurement low weight */
	N.pings_sent = 1;
	N.pings_recv = 1;
	if ((t = strtok(NULL, w_space)) == NULL)
	    continue;
	N.hops = atof(t);
	if ((t = strtok(NULL, w_space)) == NULL)
	    continue;
	N.rtt = atof(t);
	if ((t = strtok(NULL, w_space)) == NULL)
	    continue;
	N.next_ping_time = (time_t) atoi(t);
	if ((t = strtok(NULL, w_space)) == NULL)
	    continue;
	N.last_use_time = (time_t) atoi(t);
	n = memAllocate(MEM_NETDBENTRY);
	xmemcpy(n, &N, sizeof(netdbEntry));
	netdbHashInsert(n, addr);
	while ((t = strtok(NULL, w_space)) != NULL) {
	    if (netdbLookupHost(t) != NULL)	/* no dups! */
		continue;
	    netdbHostInsert(n, t);
	}
	count++;
    }
    memFree(buf, MEM_4K_BUF);
    fclose(fp);
    getCurrentTime();
    debug(38, 1) ("NETDB state reloaded; %d entries, %d msec\n",
	count, tvSubMsec(start, current_time));
}

static char *
netdbPeerName(const char *name)
{
    wordlist *w;
    for (w = peer_names; w; w = w->next) {
	if (!strcmp(w->key, name))
	    return w->key;
    }
    w = wordlistAdd(&peer_names, name);
    return w->key;
}

static void
netdbFreeNetdbEntry(void *data)
{
    netdbEntry *n = data;
    safe_free(n->peers);
    memFree(n, MEM_NETDBENTRY);
}

static void
netdbFreeNameEntry(void *data)
{
    net_db_name *x = data;
    xfree(x->name);
    memFree(x, MEM_NET_DB_NAME);
}

static void
netdbExchangeHandleReply(void *data, char *buf, ssize_t size)
{
    netdbExchangeState *ex = data;
    int rec_sz = 0;
    off_t o;
    struct in_addr addr;
    double rtt;
    double hops;
    char *p;
    int j;
    HttpReply *rep;
    size_t hdr_sz;
    int nused = 0;