usr.sbin/snoop/snoop_ipaddr.c

	snoop_ipaddr.c revision b127ac411761a3d8d642d9342d9cac2785e1faaa
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <net/if.h>
#include <netinet/in_systm.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <netinet/ip.h>
#include <netdb.h>
#include <string.h>
#include <signal.h>
#include <setjmp.h>
#include <arpa/inet.h>
#include "snoop.h"

static sigjmp_buf nisjmp;

#define MAXHASH 1024  /* must be a power of 2 */

#define SEPARATORS " \t\n"

struct hostdata {
    struct hostdata *h_next;
    char        *h_hostname;
    int     h_pktsout;
    int     h_pktsin;
};

struct hostdata4 {
    struct hostdata4    *h4_next;
    char        *h4_hostname;
    int     h4_pktsout;
    int     h4_pktsin;
    struct in_addr  h4_addr;
};

struct hostdata6 {
    struct hostdata6    *h6_next;
    char        *h6_hostname;
    int     h6_pktsout;
    int     h6_pktsin;
    struct in6_addr h6_addr;
};

static struct hostdata *addhost(int, const void *, const char *, char **);

static struct hostdata4 *h_table4[MAXHASH];
static struct hostdata6 *h_table6[MAXHASH];

#define iphash(e)  ((e) & (MAXHASH-1))

/* ARGSUSED */
static void
wakeup(int n)
{
    siglongjmp(nisjmp, 1);
}

extern char *inet_ntoa();

static struct hostdata *
iplookup(struct in_addr ipaddr)
{
    register struct hostdata4 *h;
    struct hostent *hp = NULL;
    struct netent *np;
    int error_num;
    struct hostdata *retval;

    for (h = h_table4[iphash(ipaddr.s_addr)]; h; h = h->h4_next) {
        if (h->h4_addr.s_addr == ipaddr.s_addr)
            return ((struct hostdata *)h);
    }

    /* not found.  Put it in */

    if (ipaddr.s_addr == htonl(INADDR_BROADCAST))
        return (addhost(AF_INET, &ipaddr, "BROADCAST", NULL));
    if (ipaddr.s_addr == htonl(INADDR_ANY))
        return (addhost(AF_INET, &ipaddr, "OLD-BROADCAST", NULL));

    /*
     * Set an alarm here so we don't get held up by
     * an unresponsive name server.
     * Give it 3 sec to do its work.
     */
    if (! rflg && sigsetjmp(nisjmp, 1) == 0) {
        (void) snoop_alarm(3, wakeup);
        hp = getipnodebyaddr((char *)&ipaddr, sizeof (int),
            AF_INET, &error_num);
        if (hp == NULL && inet_lnaof(ipaddr) == 0) {
            np = getnetbyaddr(inet_netof(ipaddr), AF_INET);
            if (np)
                return (addhost(AF_INET, &ipaddr, np->n_name,
                    np->n_aliases));
        }
        (void) snoop_alarm(0, wakeup);
    }

    retval = addhost(AF_INET, &ipaddr,
        hp ? hp->h_name : inet_ntoa(ipaddr),
        hp ? hp->h_aliases : NULL);
    if (hp != NULL)
        freehostent(hp);
    return (retval);
}

static struct hostdata *
ip6lookup(const struct in6_addr *ip6addr)
{
    struct hostdata6 *h;
    struct hostent *hp = NULL;
    int error_num;
    char addrstr[INET6_ADDRSTRLEN];
    char *addname;
    struct hostdata *retval;

    for (h = h_table6[iphash(((uint32_t *)ip6addr)[3])]; h;
        h = h->h6_next) {
        if (IN6_ARE_ADDR_EQUAL(&h->h6_addr, ip6addr))
            return ((struct hostdata *)h);
    }

    /* not in the hash table, put it in */
    if (IN6_IS_ADDR_UNSPECIFIED(ip6addr))
        return (addhost(AF_INET6, ip6addr, "UNSPECIFIED", NULL));

    /*
     * Set an alarm here so we don't get held up by
     * an unresponsive name server.
     * Give it 3 sec to do its work.
     */
    if (! rflg && sigsetjmp(nisjmp, 1) == 0) {
        (void) snoop_alarm(3, wakeup);
        hp = getipnodebyaddr(ip6addr, sizeof (struct in6_addr),
            AF_INET6, &error_num);
        (void) snoop_alarm(0, wakeup);
    } else {
        hp = NULL;
    }

    if (hp != NULL)
        addname = hp->h_name;
    else {
        (void) inet_ntop(AF_INET6, ip6addr, addrstr, INET6_ADDRSTRLEN);
        addname = addrstr;
    }

    retval = addhost(AF_INET6, ip6addr, addname, hp ? hp->h_aliases : NULL);
    if (hp != NULL)
        freehostent(hp);
    return (retval);
}

static struct hostdata *
addhost(int family, const void *ipaddr, const char *name, char **aliases)
{
    struct hostdata **hp, *n = NULL;
    extern FILE *namefile;
    int hashval;
    static char aname[128];
    char *np;
    static struct hostdata h;
    int ind;

    switch (family) {
    case AF_INET:
        n = (struct hostdata *)malloc(sizeof (struct hostdata4));
        if (n == NULL)
            goto alloc_failed;

        memset(n, 0, sizeof (struct hostdata4));
        n->h_hostname = strdup(name);
        if (n->h_hostname == NULL)
            goto alloc_failed;

        ((struct hostdata4 *)n)->h4_addr =
            *(const struct in_addr *)ipaddr;
        hashval = ((struct in_addr *)ipaddr)->s_addr;
        hp = (struct hostdata **)&h_table4[iphash(hashval)];
        break;
    case AF_INET6:
        n = (struct hostdata *)malloc(sizeof (struct hostdata6));
        if (n == NULL)
            goto alloc_failed;

        memset(n, 0, sizeof (struct hostdata6));
        n->h_hostname = strdup(name);
        if (n->h_hostname == NULL)
            goto alloc_failed;

        memcpy(&((struct hostdata6 *)n)->h6_addr, ipaddr,
            sizeof (struct in6_addr));
        hashval = ((const int *)ipaddr)[3];
        hp = (struct hostdata **)&h_table6[iphash(hashval)];
        break;
    default:
        fprintf(stderr, "snoop: ERROR: Unknown address family: %d",
            family);
        exit(1);
    }

    n->h_next = *hp;
    *hp = n;

    if (namefile != NULL) {
        if (family == AF_INET) {
            np = inet_ntoa(*(const struct in_addr *)ipaddr);
            if (np) {
                (void) fprintf(namefile, "%s\t%s", np, name);
                if (aliases) {
                    for (ind = 0;
                        aliases[ind] != NULL;
                        ind++) {
                        (void) fprintf(namefile, " %s",
                            aliases[ind]);
                    }
                }
                (void) fprintf(namefile, "\n");
            }
        } else if (family == AF_INET6) {
            np = (char *)inet_ntop(AF_INET6, (void *)ipaddr, aname,
                sizeof (aname));
            if (np) {
                (void) fprintf(namefile, "%s\t%s", np, name);
                if (aliases) {
                    for (ind = 0;
                        aliases[ind] != NULL;
                        ind++) {
                        (void) fprintf(namefile, " %s",
                            aliases[ind]);
                    }
                }
                (void) fprintf(namefile, "\n");
            }
        } else {
            (void) fprintf(stderr, "addhost: unknown family %d\n",
                family);
        }
    }
    return (n);

alloc_failed:
    if (n)
        free(n);
    (void) fprintf(stderr, "addhost: no mem\n");

    aname[0] = '\0';
    memset(&h, 0, sizeof (struct hostdata));
    h.h_hostname = aname;
    return (&h);
}

char *
addrtoname(int family, const void *ipaddr)
{
    switch (family) {
    case AF_INET:
        return (iplookup(*(const struct in_addr *)ipaddr)->h_hostname);
    case AF_INET6:
        return (ip6lookup((const struct in6_addr *)ipaddr)->h_hostname);
    }
    (void) fprintf(stderr, "snoop: ERROR: unknown address family: %d\n",
        family);
    exit(1);
    /* NOTREACHED */
}

void
load_names(fname)
    char *fname;
{
    char buf[1024];
    char *addr, *name, *alias;
    FILE *f;
    unsigned int addrv4;
    struct in6_addr addrv6;
    int family;
    void *naddr;

    (void) fprintf(stderr, "Loading name file %s\n", fname);
    f = fopen(fname, "r");
    if (f == NULL) {
        perror(fname);
        return;
    }

    while (fgets(buf, 1024, f) != NULL) {
        addr = strtok(buf, SEPARATORS);
        if (addr == NULL || *addr == '#')
            continue;
        if (inet_pton(AF_INET6, addr, (void *)&addrv6) == 1) {
            family = AF_INET6;
            naddr = (void *)&addrv6;
        } else if ((addrv4 = inet_addr(addr)) != (ulong_t)-1) {
            family = AF_INET;
            naddr = (void *)&addrv4;
        }
        name = strtok(NULL, SEPARATORS);
        if (name == NULL)
            continue;
        while ((alias = strtok(NULL, SEPARATORS)) != NULL &&
            (*alias != '#')) {
            (void) addhost(family, naddr, alias, NULL);
        }
        (void) addhost(family, naddr, name, NULL);
        /* Note: certain addresses such as broadcast are skipped */
    }

    (void) fclose(f);
}

/*
 * lgetipnodebyname: looks up hostname in cached address data. This allows
 * filtering on hostnames from the .names file to work properly, and
 * avoids name clashes between domains. Note that only the first of the
 * ipv4, ipv6, or v4mapped address will be returned, because the
 * cache does not contain information on multi-homed hosts.
 */
/*ARGSUSED*/
struct hostent *
lgetipnodebyname(const char *name, int af, int flags, int *error_num)
{
    int i;
    struct hostdata4 *h;
    struct hostdata6 *h6;
    static struct hostent he;       /* host entry */
    static struct in6_addr h46_addr[MAXADDRS];  /* v4mapped address */
    static char h_name[MAXHOSTNAMELEN]; /* hostname */
    static char *list[MAXADDRS];        /* addr_list array */
    struct hostent *hp = &he;
    int ind;

    (void) memset((char *)hp, 0, sizeof (struct hostent));
    hp->h_name = h_name;
    h_name[0] = '\0';
    strcpy(h_name, name);

    hp->h_addrtype = AF_INET6;

    hp->h_addr_list = list;
    for (i = 0; i < MAXADDRS; i++)
        hp->h_addr_list[i] = NULL;
    ind = 0;

    /* ipv6 lookup */
    if (af == AF_INET6) {
        hp->h_length = sizeof (struct in6_addr);
        for (i = 0; i < MAXHASH; i++) {
            for (h6 = h_table6[i]; h6; h6 = h6->h6_next) {
                if (strcmp(name, h6->h6_hostname) == 0) {
                    if (ind >= MAXADDRS - 1) {
                        /* too many addresses */
                        return (hp);
                    }
                    /* found ipv6 addr */
                    hp->h_addr_list[ind] =
                        (char *)&h6->h6_addr;
                    ind++;
                }
            }
        }
    }
    /* ipv4 or v4mapped lookup */
    if (af == AF_INET || (flags & AI_ALL)) {
        for (i = 0; i < MAXHASH; i++) {
            for (h = h_table4[i]; h; h = h->h4_next) {
                if (strcmp(name, h->h4_hostname) == 0) {
                    if (ind >= MAXADDRS - 1) {
                        /* too many addresses */
                        return (hp);
                    }
                    if (af == AF_INET) {
                        /* found ipv4 addr */
                        hp->h_addrtype = AF_INET;
                        hp->h_length =
                            sizeof (struct in_addr);
                        hp->h_addr_list[ind] =
                            (char *)&h->h4_addr;
                        ind++;
                    } else {
                        /* found v4mapped addr */
                        hp->h_length =
                            sizeof (struct in6_addr);
                        hp->h_addr_list[ind] =
                            (char *)&h46_addr[ind];
                        IN6_INADDR_TO_V4MAPPED(
                            &h->h4_addr,
                            &h46_addr[ind]);
                        ind++;
                    }
                }
            }
        }
    }
    return (ind > 0 ? hp : NULL);
}