isc/unix/interfaceiter.c

/*
 * Copyright (C) 1999-2005, 2007, 2008, 2014, 2016, 2017  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: 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;
    unsigned 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);
    strlcpy(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;
}