libnsl/nss/inet_matchaddr.c

	inet_matchaddr.c revision 9b241b4ed1cf882400b069ff9853cdd310d469bf
/*
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms of version
 * 1.0 of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source.  A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 *
 * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
 */

/*
 * inet_matchaddr
 *
 * Match IPv4 or IPv6 address provided in sa (sockaddr_in/sockaddr_in6)
 * against standard text representation specified in name:
 *
 * IPv4:
 *  IPv4
 *  IPv4/netmask
 *
 * IPv6:
 *  [IPv6]
 *  [IPv6]/prefix
 */

#include <sys/socket.h>
#include <sys/types.h>

#include <arpa/inet.h>

#include <netinet/in.h>

#include <ctype.h>
#include <err.h>
#include <netdb.h>
#include <stdlib.h>
#include <strings.h>


boolean_t
inet_matchaddr(const void *sa, const char *name)
{
    boolean_t ret = B_FALSE;
    char *lname, *mp, *p;
    uint32_t claddr4 = 0;

    if ((p = lname = strdup(name)) == NULL)
        err(1, "strdup");

    if ((mp = strchr(p, '/')) != NULL)
        *mp++ = '\0';

    switch (((struct sockaddr_in *)sa)->sin_family) {
    case AF_INET6: {
        char *pp;
        int prefix6;
        ipaddr_t ipaddr4;
        struct in6_addr hcaddr6;
        struct in6_addr *claddr6 =
            &((struct sockaddr_in6 *)sa)->sin6_addr;

        if (!IN6_IS_ADDR_V4MAPPED(claddr6)) {
            /* IPv6 address */
            if ((p = strchr(p, '[')) == NULL)
                break;
            p++;

            if ((pp = strchr(p, ']')) == NULL)
                break;
            *pp = '\0';

            if (inet_pton(AF_INET6, p, &hcaddr6) != 1)
                break;

            if (mp != NULL) {
                /* Match only first prefix bits */
                if ((prefix6 = (int)strtol(mp,
                    (char **)NULL, 10)) == 0)
                    break;
                ret = IN6_ARE_PREFIXEDADDR_EQUAL(claddr6,
                    &hcaddr6, prefix6);
                break;
            } else {
                /* No prefix, exact match */
                ret = IN6_ARE_ADDR_EQUAL(claddr6, &hcaddr6);
                break;
            }
        } else {
            /* IPv4-mapped IPv6 address, fallthrough to IPv4 */
            IN6_V4MAPPED_TO_IPADDR(claddr6, ipaddr4);
            claddr4 = ntohl(ipaddr4);
        }
        /*FALLTHROUGH*/
    }
    case AF_INET: {
        int bits, i;
        uint32_t hcaddr4 = 0, mask4;

        if (claddr4 == 0)
            claddr4 = ntohl(
                ((struct sockaddr_in *)sa)->sin_addr.s_addr);

        for (i = 0; i < 4; i++) {
            hcaddr4 |= (int)strtol(p, (char **)NULL, 10) <<
                ((3 - i) * 8);
            if ((p = strchr(p, '.')) == NULL)
                break;
            p++;
        }

        if (hcaddr4 == 0)
            break;

        if (mp != NULL) {
            /* Mask is specified explicitly */
            if ((bits = (int)strtol(mp, (char **)NULL, 10)) == 0)
                break;
            mask4 = bits ? ~0 << ((sizeof (struct in_addr) * NBBY)
                - bits) : 0;
            hcaddr4 &= mask4;
        } else {
            /*
             * Use old-fashioned implicit netmasking by checking
             * for lower-end zeroes. On the off chance we don't
             * match any well-known prefixes, return an exact-
             * match prefix which is misleadingly labelled as
             * IN_CLASSE_NET.
             */
            if ((hcaddr4 & IN_CLASSA_HOST) == 0)
                mask4 = IN_CLASSA_NET;
            else if ((hcaddr4 & IN_CLASSB_HOST) == 0)
                mask4 = IN_CLASSB_NET;
            else if ((hcaddr4 & IN_CLASSC_HOST) == 0)
                mask4 = IN_CLASSC_NET;
            else
                mask4 = IN_CLASSE_NET;
        }

        ret = ((claddr4 & mask4) == hcaddr4);
        break;
    }
    }

    free(lname);

    return (ret);
}