isc/unix/ifiter_getifaddrs.c

	ifiter_getifaddrs.c revision 0c27b3fe77ac1d5094ba3521e8142d9e7973133f
/*
 * Copyright (C) 2003-2005, 2007-2009, 2014, 2016  Internet Systems Consortium, Inc. ("ISC")
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

/* $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;
}