interfaceiter.c

Go to the documentation of this file.

/*
 * Copyright (C) 2004, 2005, 2007, 2008, 2014  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 1999-2003  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: interfaceiter.c,v 1.45 2008/12/01 03:51:47 marka Exp $ */

/*! \file */

#include <config.h>

#include <sys/types.h>
#include <sys/ioctl.h>
#ifdef HAVE_SYS_SOCKIO_H
#include <sys/sockio.h>         /* Required for ifiter_ioctl.c. */
#endif

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>

#include <isc/interfaceiter.h>
#include <isc/log.h>
#include <isc/magic.h>
#include <isc/mem.h>
#include <isc/msgs.h>
#include <isc/net.h>
#include <isc/print.h>
#include <isc/result.h>
#include <isc/strerror.h>
#include <isc/string.h>
#include <isc/types.h>
#include <isc/util.h>

/* Must follow <isc/net.h>. */
#ifdef HAVE_NET_IF6_H
#include <net/if6.h>
#endif
#include <net/if.h>

/* Common utility functions */

/*%
 * Extract the network address part from a "struct sockaddr".
 * \brief
 * The address family is given explicitly
 * instead of using src->sa_family, because the latter does not work
 * for copying a network mask obtained by SIOCGIFNETMASK (it does
 * not have a valid address family).
 */

static void
get_addr(unsigned int family, isc_netaddr_t *dst, struct sockaddr *src,
         char *ifname)
{
        struct sockaddr_in6 *sa6;

#if !defined(ISC_PLATFORM_HAVEIFNAMETOINDEX) || \
    !defined(ISC_PLATFORM_HAVESCOPEID)
        UNUSED(ifname);
#endif

        /* clear any remaining value for safety */
        memset(dst, 0, sizeof(*dst));

        dst->family = family;
        switch (family) {
        case AF_INET:
                memmove(&dst->type.in,
                        &((struct sockaddr_in *) src)->sin_addr,
                        sizeof(struct in_addr));
                break;
        case AF_INET6:
                sa6 = (struct sockaddr_in6 *)src;
                memmove(&dst->type.in6, &sa6->sin6_addr,
                        sizeof(struct in6_addr));
#ifdef ISC_PLATFORM_HAVESCOPEID
                if (sa6->sin6_scope_id != 0)
                        isc_netaddr_setzone(dst, sa6->sin6_scope_id);
                else {
                        /*
                         * BSD variants embed scope zone IDs in the 128bit
                         * address as a kernel internal form.  Unfortunately,
                         * the embedded IDs are not hidden from applications
                         * when getting access to them by sysctl or ioctl.
                         * We convert the internal format to the pure address
                         * part and the zone ID part.
                         * Since multicast addresses should not appear here
                         * and they cannot be distinguished from netmasks,
                         * we only consider unicast link-local addresses.
                         */
                        if (IN6_IS_ADDR_LINKLOCAL(&sa6->sin6_addr)) {
                                isc_uint16_t zone16;

                                memmove(&zone16, &sa6->sin6_addr.s6_addr[2],
                                        sizeof(zone16));
                                zone16 = ntohs(zone16);
                                if (zone16 != 0) {
                                        /* the zone ID is embedded */
                                        isc_netaddr_setzone(dst,
                                                            (isc_uint32_t)zone16);
                                        dst->type.in6.s6_addr[2] = 0;
                                        dst->type.in6.s6_addr[3] = 0;
#ifdef ISC_PLATFORM_HAVEIFNAMETOINDEX
                                } else if (ifname != NULL) {
                                        unsigned int zone;

                                        /*
                                         * sin6_scope_id is still not provided,
                                         * but the corresponding interface name
                                         * is know.  Use the interface ID as
                                         * the link ID.
                                         */
                                        zone = if_nametoindex(ifname);
                                        if (zone != 0) {
                                                isc_netaddr_setzone(dst,
                                                                    (isc_uint32_t)zone);
                                        }
#endif
                                }
                        }
                }
#endif
                break;
        default:
                INSIST(0);
                break;
        }
}

/*
 * Include system-dependent code.
 */

#ifdef __linux
#define ISC_IF_INET6_SZ \
    sizeof("00000000000000000000000000000001 01 80 10 80 XXXXXXloXXXXXXXX\n")
static isc_result_t linux_if_inet6_next(isc_interfaceiter_t *);
static isc_result_t linux_if_inet6_current(isc_interfaceiter_t *);
static void linux_if_inet6_first(isc_interfaceiter_t *iter);
#endif

#if HAVE_GETIFADDRS
#include "ifiter_getifaddrs.c"
#elif HAVE_IFLIST_SYSCTL
#include "ifiter_sysctl.c"
#else
#include "ifiter_ioctl.c"
#endif

#ifdef __linux
static void
linux_if_inet6_first(isc_interfaceiter_t *iter) {
        if (iter->proc != NULL) {
                rewind(iter->proc);
                (void)linux_if_inet6_next(iter);
        } else
                iter->valid = ISC_R_NOMORE;
}

static isc_result_t
linux_if_inet6_next(isc_interfaceiter_t *iter) {
        if (iter->proc != NULL &&
            fgets(iter->entry, sizeof(iter->entry), iter->proc) != NULL)
                iter->valid = ISC_R_SUCCESS;
        else
                iter->valid = ISC_R_NOMORE;
        return (iter->valid);
}

static isc_result_t
linux_if_inet6_current(isc_interfaceiter_t *iter) {
        char address[33];
        char name[IF_NAMESIZE+1];
        struct in6_addr addr6;
        int ifindex, prefix, flag3, flag4;
        int res;
        unsigned int i;

        if (iter->valid != ISC_R_SUCCESS)
                return (iter->valid);
        if (iter->proc == NULL) {
                isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
                              ISC_LOGMODULE_INTERFACE, ISC_LOG_ERROR,
                              "/proc/net/if_inet6:iter->proc == NULL");
                return (ISC_R_FAILURE);
        }

        res = sscanf(iter->entry, "%32[a-f0-9] %x %x %x %x %16s\n",
                     address, &ifindex, &prefix, &flag3, &flag4, name);
        if (res != 6) {
                isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
                              ISC_LOGMODULE_INTERFACE, ISC_LOG_ERROR,
                              "/proc/net/if_inet6:sscanf() -> %d (expected 6)",
                              res);
                return (ISC_R_FAILURE);
        }
        if (strlen(address) != 32) {
                isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
                              ISC_LOGMODULE_INTERFACE, ISC_LOG_ERROR,
                              "/proc/net/if_inet6:strlen(%s) != 32", address);
                return (ISC_R_FAILURE);
        }
        for (i = 0; i < 16; i++) {
                unsigned char byte;
                static const char hex[] = "0123456789abcdef";
                byte = ((strchr(hex, address[i * 2]) - hex) << 4) |
                       (strchr(hex, address[i * 2 + 1]) - hex);
                addr6.s6_addr[i] = byte;
        }
        iter->current.af = AF_INET6;
        iter->current.flags = INTERFACE_F_UP;
        isc_netaddr_fromin6(&iter->current.address, &addr6);
        if (isc_netaddr_islinklocal(&iter->current.address)) {
                isc_netaddr_setzone(&iter->current.address,
                                    (isc_uint32_t)ifindex);
        }
        for (i = 0; i < 16; i++) {
                if (prefix > 8) {
                        addr6.s6_addr[i] = 0xff;
                        prefix -= 8;
                } else {
                        addr6.s6_addr[i] = (0xff << (8 - prefix)) & 0xff;
                        prefix = 0;
                }
        }
        isc_netaddr_fromin6(&iter->current.netmask, &addr6);
        strncpy(iter->current.name, name, sizeof(iter->current.name));
        return (ISC_R_SUCCESS);
}
#endif

/*
 * The remaining code is common to the sysctl and ioctl case.
 */

isc_result_t
isc_interfaceiter_current(isc_interfaceiter_t *iter,
                          isc_interface_t *ifdata)
{
        REQUIRE(iter->result == ISC_R_SUCCESS);
        memmove(ifdata, &iter->current, sizeof(*ifdata));
        return (ISC_R_SUCCESS);
}

isc_result_t
isc_interfaceiter_first(isc_interfaceiter_t *iter) {
        isc_result_t result;

        REQUIRE(VALID_IFITER(iter));

        internal_first(iter);
        for (;;) {
                result = internal_current(iter);
                if (result != ISC_R_IGNORE)
                        break;
                result = internal_next(iter);
                if (result != ISC_R_SUCCESS)
                        break;
        }
        iter->result = result;
        return (result);
}

isc_result_t
isc_interfaceiter_next(isc_interfaceiter_t *iter) {
        isc_result_t result;

        REQUIRE(VALID_IFITER(iter));
        REQUIRE(iter->result == ISC_R_SUCCESS);

        for (;;) {
                result = internal_next(iter);
                if (result != ISC_R_SUCCESS)
                        break;
                result = internal_current(iter);
                if (result != ISC_R_IGNORE)
                        break;
        }
        iter->result = result;
        return (result);
}

void
isc_interfaceiter_destroy(isc_interfaceiter_t **iterp)
{
        isc_interfaceiter_t *iter;
        REQUIRE(iterp != NULL);
        iter = *iterp;
        REQUIRE(VALID_IFITER(iter));

        internal_destroy(iter);
        if (iter->buf != NULL)
                isc_mem_put(iter->mctx, iter->buf, iter->bufsize);

        iter->magic = 0;
        isc_mem_put(iter->mctx, iter, sizeof(*iter));
        *iterp = NULL;
}

---