ifiter_getifaddrs.c

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/*
 * Copyright (C) 2004, 2005, 2007-2009, 2014  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 2003  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

/* $Id: ifiter_getifaddrs.c,v 1.13 2009/09/24 23:48:13 tbox Exp $ */

/*! \file
 * \brief
 * Obtain the list of network interfaces using the getifaddrs(3) library.
 */

#include <ifaddrs.h>

/*% Iterator Magic */
#define IFITER_MAGIC            ISC_MAGIC('I', 'F', 'I', 'G')
/*% Valid Iterator */
#define VALID_IFITER(t)         ISC_MAGIC_VALID(t, IFITER_MAGIC)

#ifdef __linux
static isc_boolean_t seenv6 = ISC_FALSE;
#endif

/*% Iterator structure */
struct isc_interfaceiter {
        unsigned int            magic;          /*%< Magic number. */
        isc_mem_t               *mctx;
        void                    *buf;           /*%< (unused) */
        unsigned int            bufsize;        /*%< (always 0) */
        struct ifaddrs          *ifaddrs;       /*%< List of ifaddrs */
        struct ifaddrs          *pos;           /*%< Ptr to current ifaddr */
        isc_interface_t         current;        /*%< Current interface data. */
        isc_result_t            result;         /*%< Last result code. */
#ifdef  __linux
        FILE *                  proc;
        char                    entry[ISC_IF_INET6_SZ];
        isc_result_t            valid;
#endif
};

isc_result_t
isc_interfaceiter_create(isc_mem_t *mctx, isc_interfaceiter_t **iterp) {
        isc_interfaceiter_t *iter;
        isc_result_t result;
        char strbuf[ISC_STRERRORSIZE];

        REQUIRE(mctx != NULL);
        REQUIRE(iterp != NULL);
        REQUIRE(*iterp == NULL);

        iter = isc_mem_get(mctx, sizeof(*iter));
        if (iter == NULL)
                return (ISC_R_NOMEMORY);

        iter->mctx = mctx;
        iter->buf = NULL;
        iter->bufsize = 0;
        iter->ifaddrs = NULL;
#ifdef __linux
        /*
         * Only open "/proc/net/if_inet6" if we have never seen a IPv6
         * address returned by getifaddrs().
         */
        if (!seenv6)
                iter->proc = fopen("/proc/net/if_inet6", "r");
        else
                iter->proc = NULL;
        iter->valid = ISC_R_FAILURE;
#endif

        if (getifaddrs(&iter->ifaddrs) < 0) {
                isc__strerror(errno, strbuf, sizeof(strbuf));
                UNEXPECTED_ERROR(__FILE__, __LINE__,
                                 isc_msgcat_get(isc_msgcat,
                                                ISC_MSGSET_IFITERGETIFADDRS,
                                                ISC_MSG_GETIFADDRS,
                                                "getting interface "
                                                "addresses: getifaddrs: %s"),
                                 strbuf);
                result = ISC_R_UNEXPECTED;
                goto failure;
        }

        /*
         * A newly created iterator has an undefined position
         * until isc_interfaceiter_first() is called.
         */
        iter->pos = NULL;
        iter->result = ISC_R_FAILURE;

        iter->magic = IFITER_MAGIC;
        *iterp = iter;
        return (ISC_R_SUCCESS);

 failure:
#ifdef __linux
        if (iter->proc != NULL)
                fclose(iter->proc);
#endif
        if (iter->ifaddrs != NULL) /* just in case */
                freeifaddrs(iter->ifaddrs);
        isc_mem_put(mctx, iter, sizeof(*iter));
        return (result);
}

/*
 * Get information about the current interface to iter->current.
 * If successful, return ISC_R_SUCCESS.
 * If the interface has an unsupported address family,
 * return ISC_R_IGNORE.
 */

static isc_result_t
internal_current(isc_interfaceiter_t *iter) {
        struct ifaddrs *ifa;
        int family;
        unsigned int namelen;

        REQUIRE(VALID_IFITER(iter));

        ifa = iter->pos;

#ifdef __linux
        if (iter->pos == NULL)
                return (linux_if_inet6_current(iter));
#endif

        INSIST(ifa != NULL);
        INSIST(ifa->ifa_name != NULL);

        if (ifa->ifa_addr == NULL)
                return (ISC_R_IGNORE);

        family = ifa->ifa_addr->sa_family;
        if (family != AF_INET && family != AF_INET6)
                return (ISC_R_IGNORE);

#ifdef __linux
        if (family == AF_INET6)
                seenv6 = ISC_TRUE;
#endif

        memset(&iter->current, 0, sizeof(iter->current));

        namelen = strlen(ifa->ifa_name);
        if (namelen > sizeof(iter->current.name) - 1)
                namelen = sizeof(iter->current.name) - 1;

        memset(iter->current.name, 0, sizeof(iter->current.name));
        memmove(iter->current.name, ifa->ifa_name, namelen);

        iter->current.flags = 0;

        if ((ifa->ifa_flags & IFF_UP) != 0)
                iter->current.flags |= INTERFACE_F_UP;

        if ((ifa->ifa_flags & IFF_POINTOPOINT) != 0)
                iter->current.flags |= INTERFACE_F_POINTTOPOINT;

        if ((ifa->ifa_flags & IFF_LOOPBACK) != 0)
                iter->current.flags |= INTERFACE_F_LOOPBACK;

        iter->current.af = family;

        get_addr(family, &iter->current.address, ifa->ifa_addr, ifa->ifa_name);

        if (ifa->ifa_netmask != NULL)
                get_addr(family, &iter->current.netmask, ifa->ifa_netmask,
                         ifa->ifa_name);

        if (ifa->ifa_dstaddr != NULL &&
            (iter->current.flags & INTERFACE_F_POINTTOPOINT) != 0)
                get_addr(family, &iter->current.dstaddress, ifa->ifa_dstaddr,
                         ifa->ifa_name);

        return (ISC_R_SUCCESS);
}

/*
 * Step the iterator to the next interface.  Unlike
 * isc_interfaceiter_next(), this may leave the iterator
 * positioned on an interface that will ultimately
 * be ignored.  Return ISC_R_NOMORE if there are no more
 * interfaces, otherwise ISC_R_SUCCESS.
 */
static isc_result_t
internal_next(isc_interfaceiter_t *iter) {

        if (iter->pos != NULL)
                iter->pos = iter->pos->ifa_next;
        if (iter->pos == NULL) {
#ifdef __linux
                if (!seenv6)
                        return (linux_if_inet6_next(iter));
#endif
                return (ISC_R_NOMORE);
        }

        return (ISC_R_SUCCESS);
}

static void
internal_destroy(isc_interfaceiter_t *iter) {

#ifdef __linux
        if (iter->proc != NULL)
                fclose(iter->proc);
        iter->proc = NULL;
#endif
        if (iter->ifaddrs)
                freeifaddrs(iter->ifaddrs);
        iter->ifaddrs = NULL;
}

static
void internal_first(isc_interfaceiter_t *iter) {

#ifdef __linux
        linux_if_inet6_first(iter);
#endif
        iter->pos = iter->ifaddrs;
}

---