*: change if_lookup_by_name() api with vrf

[mirror_frr.git] / zebra / kernel_socket.c

/* Kernel communication using routing socket.
 * Copyright (C) 1999 Kunihiro Ishiguro
 *
 * This file is part of GNU Zebra.
 *
 * GNU Zebra is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2, or (at your option) any
 * later version.
 *
 * GNU Zebra is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; see the file COPYING; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <zebra.h>

#ifndef HAVE_NETLINK

#include <net/if_types.h>
#ifdef __OpenBSD__
#include <netmpls/mpls.h>
#endif

#include "if.h"
#include "prefix.h"
#include "sockunion.h"
#include "connected.h"
#include "memory.h"
#include "zebra_memory.h"
#include "ioctl.h"
#include "log.h"
#include "table.h"
#include "rib.h"
#include "privs.h"
#include "vrf.h"
#include "lib_errors.h"

#include "zebra/rt.h"
#include "zebra/interface.h"
#include "zebra/zebra_router.h"
#include "zebra/debug.h"
#include "zebra/kernel_socket.h"
#include "zebra/rib.h"
#include "zebra/zebra_errors.h"
#include "zebra/zebra_ptm.h"

extern struct zebra_privs_t zserv_privs;

/*
 * Historically, the BSD routing socket has aligned data following a
 * struct sockaddr to sizeof(long), which was 4 bytes on some
 * platforms, and 8 bytes on others.  NetBSD 6 changed the routing
 * socket to align to sizeof(uint64_t), which is 8 bytes.  OS X
 * appears to align to sizeof(int), which is 4 bytes.
 *
 * Alignment of zero-sized sockaddrs is nonsensical, but historically
 * BSD defines RT_ROUNDUP(0) to be the alignment interval (rather than
 * 0).  We follow this practice without questioning it, but it is a
 * bug if quagga calls ROUNDUP with 0.
 */
#ifdef __APPLE__
#define ROUNDUP_TYPE    int
#else
#define ROUNDUP_TYPE    long
#endif

/*
 * Because of these varying conventions, the only sane approach is for
 * the <net/route.h> header to define some flavor of ROUNDUP macro.
 */

/* OS X (Xcode as of 2014-12) is known not to define RT_ROUNDUP */
#if defined(RT_ROUNDUP)
#define ROUNDUP(a)      RT_ROUNDUP(a)
#endif /* defined(RT_ROUNDUP) */

#if defined(SUNOS_5)
/* Solaris has struct sockaddr_in[6] definitions at 16 / 32 bytes size,
 * so the whole concept doesn't really apply. */
#define ROUNDUP(a)      (a)
#endif

/*
 * If ROUNDUP has not yet been defined in terms of platform-provided
 * defines, attempt to cope with heuristics.
 */
#if !defined(ROUNDUP)

/*
 * If you're porting to a platform that changed RT_ROUNDUP but doesn't
 * have it in its headers, this will break rather obviously and you'll
 * have to fix it here.
 */
#define ROUNDUP(a)                                                             \
        ((a) > 0 ? (1 + (((a)-1) | (sizeof(ROUNDUP_TYPE) - 1)))                \
                 : sizeof(ROUNDUP_TYPE))

#endif /* defined(ROUNDUP) */


#if defined(SA_SIZE)
/* SAROUNDUP is the only thing we need, and SA_SIZE provides that */
#define SAROUNDUP(a)    SA_SIZE(a)
#else /* !SA_SIZE */
/*
 * Given a pointer (sockaddr or void *), return the number of bytes
 * taken up by the sockaddr and any padding needed for alignment.
 */
#if defined(HAVE_STRUCT_SOCKADDR_SA_LEN)
#define SAROUNDUP(X)   ROUNDUP(((struct sockaddr *)(X))->sa_len)
#else
/*
 * One would hope all fixed-size structure definitions are aligned,
 * but round them up nonetheless.
 */
#define SAROUNDUP(X)                                                           \
        (((struct sockaddr *)(X))->sa_family == AF_INET                        \
                 ? ROUNDUP(sizeof(struct sockaddr_in))                         \
                 : (((struct sockaddr *)(X))->sa_family == AF_INET6            \
                            ? ROUNDUP(sizeof(struct sockaddr_in6))             \
                            : (((struct sockaddr *)(X))->sa_family == AF_LINK  \
                                       ? ROUNDUP(sizeof(struct sockaddr_dl))   \
                                       : sizeof(struct sockaddr))))
#endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */

#endif /* !SA_SIZE */

/* Routing socket message types. */
const struct message rtm_type_str[] = {{RTM_ADD, "RTM_ADD"},
                                       {RTM_DELETE, "RTM_DELETE"},
                                       {RTM_CHANGE, "RTM_CHANGE"},
                                       {RTM_GET, "RTM_GET"},
                                       {RTM_LOSING, "RTM_LOSING"},
                                       {RTM_REDIRECT, "RTM_REDIRECT"},
                                       {RTM_MISS, "RTM_MISS"},
#ifdef RTM_LOCK
                                       {RTM_LOCK, "RTM_LOCK"},
#endif /* RTM_LOCK */
#ifdef OLDADD
                                       {RTM_OLDADD, "RTM_OLDADD"},
#endif /* RTM_OLDADD */
#ifdef RTM_OLDDEL
                                       {RTM_OLDDEL, "RTM_OLDDEL"},
#endif /* RTM_OLDDEL */
#ifdef RTM_RESOLVE
                                       {RTM_RESOLVE, "RTM_RESOLVE"},
#endif  /* RTM_RESOLVE */
                                       {RTM_NEWADDR, "RTM_NEWADDR"},
                                       {RTM_DELADDR, "RTM_DELADDR"},
                                       {RTM_IFINFO, "RTM_IFINFO"},
#ifdef RTM_OIFINFO
                                       {RTM_OIFINFO, "RTM_OIFINFO"},
#endif /* RTM_OIFINFO */
#ifdef RTM_NEWMADDR
                                       {RTM_NEWMADDR, "RTM_NEWMADDR"},
#endif /* RTM_NEWMADDR */
#ifdef RTM_DELMADDR
                                       {RTM_DELMADDR, "RTM_DELMADDR"},
#endif /* RTM_DELMADDR */
#ifdef RTM_IFANNOUNCE
                                       {RTM_IFANNOUNCE, "RTM_IFANNOUNCE"},
#endif /* RTM_IFANNOUNCE */
                                       {0}};

static const struct message rtm_flag_str[] = {{RTF_UP, "UP"},
                                              {RTF_GATEWAY, "GATEWAY"},
                                              {RTF_HOST, "HOST"},
                                              {RTF_REJECT, "REJECT"},
                                              {RTF_DYNAMIC, "DYNAMIC"},
                                              {RTF_MODIFIED, "MODIFIED"},
                                              {RTF_DONE, "DONE"},
#ifdef RTF_MASK
                                              {RTF_MASK, "MASK"},
#endif /* RTF_MASK */
#ifdef RTF_CLONING
                                              {RTF_CLONING, "CLONING"},
#endif /* RTF_CLONING */
#ifdef RTF_XRESOLVE
                                              {RTF_XRESOLVE, "XRESOLVE"},
#endif /* RTF_XRESOLVE */
#ifdef RTF_LLINFO
                                              {RTF_LLINFO, "LLINFO"},
#endif /* RTF_LLINFO */
                                              {RTF_STATIC, "STATIC"},
                                              {RTF_BLACKHOLE, "BLACKHOLE"},
#ifdef RTF_PRIVATE
                                              {RTF_PRIVATE, "PRIVATE"},
#endif /* RTF_PRIVATE */
                                              {RTF_PROTO1, "PROTO1"},
                                              {RTF_PROTO2, "PROTO2"},
#ifdef RTF_PRCLONING
                                              {RTF_PRCLONING, "PRCLONING"},
#endif /* RTF_PRCLONING */
#ifdef RTF_WASCLONED
                                              {RTF_WASCLONED, "WASCLONED"},
#endif /* RTF_WASCLONED */
#ifdef RTF_PROTO3
                                              {RTF_PROTO3, "PROTO3"},
#endif /* RTF_PROTO3 */
#ifdef RTF_PINNED
                                              {RTF_PINNED, "PINNED"},
#endif /* RTF_PINNED */
#ifdef RTF_LOCAL
                                              {RTF_LOCAL, "LOCAL"},
#endif /* RTF_LOCAL */
#ifdef RTF_BROADCAST
                                              {RTF_BROADCAST, "BROADCAST"},
#endif /* RTF_BROADCAST */
#ifdef RTF_MULTICAST
                                              {RTF_MULTICAST, "MULTICAST"},
#endif /* RTF_MULTICAST */
#ifdef RTF_MULTIRT
                                              {RTF_MULTIRT, "MULTIRT"},
#endif /* RTF_MULTIRT */
#ifdef RTF_SETSRC
                                              {RTF_SETSRC, "SETSRC"},
#endif /* RTF_SETSRC */
                                              {0}};

/* Kernel routing update socket. */
int routing_sock = -1;

/* Kernel dataplane routing update socket, used in the dataplane pthread
 * context.
 */
int dplane_routing_sock = -1;

/* Yes I'm checking ugly routing socket behavior. */
/* #define DEBUG */

size_t _rta_get(caddr_t sap, void *destp, size_t destlen, bool checkaf);
size_t rta_get(caddr_t sap, void *dest, size_t destlen);
size_t rta_getattr(caddr_t sap, void *destp, size_t destlen);
size_t rta_getsdlname(caddr_t sap, void *dest, short *destlen);
const char *rtatostr(unsigned int flags, char *buf, size_t buflen);

/* Supported address family check. */
static inline int af_check(int family)
{
        if (family == AF_INET)
                return 1;
        if (family == AF_INET6)
                return 1;
        return 0;
}

size_t _rta_get(caddr_t sap, void *destp, size_t destlen, bool checkaf)
{
        struct sockaddr *sa = (struct sockaddr *)sap;
        struct sockaddr_dl *sdl;
        uint8_t *dest = destp;
        size_t tlen, copylen;

#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
        copylen = sa->sa_len;
        tlen = (copylen == 0) ? sizeof(ROUNDUP_TYPE) : ROUNDUP(copylen);
#else  /* !HAVE_STRUCT_SOCKADDR_SA_LEN */
        copylen = tlen = SAROUNDUP(sap);
#endif /* !HAVE_STRUCT_SOCKADDR_SA_LEN */

        if (copylen > 0 && dest != NULL) {
                if (checkaf && af_check(sa->sa_family) == 0)
                        return tlen;
                /*
                 * Handle sockaddr_dl corner case:
                 * RTA_NETMASK might be AF_LINK, but it doesn't anything
                 * relevant (e.g. zeroed out fields). Check for this
                 * case and avoid warning log message.
                 */
                if (sa->sa_family == AF_LINK) {
                        sdl = (struct sockaddr_dl *)sa;
                        if (sdl->sdl_index == 0 || sdl->sdl_nlen == 0)
                                copylen = destlen;
                }

                if (copylen > destlen) {
                        zlog_warn(
                                "%s: destination buffer too small (%zu vs %zu)",
                                __func__, copylen, destlen);
                        memcpy(dest, sap, destlen);
                } else
                        memcpy(dest, sap, copylen);
        }

        return tlen;
}

size_t rta_get(caddr_t sap, void *destp, size_t destlen)
{
        return _rta_get(sap, destp, destlen, true);
}

size_t rta_getattr(caddr_t sap, void *destp, size_t destlen)
{
        return _rta_get(sap, destp, destlen, false);
}

size_t rta_getsdlname(caddr_t sap, void *destp, short *destlen)
{
        struct sockaddr_dl *sdl = (struct sockaddr_dl *)sap;
        uint8_t *dest = destp;
        size_t tlen, copylen;

        copylen = sdl->sdl_nlen;
#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
        struct sockaddr *sa = (struct sockaddr *)sap;

        tlen = (sa->sa_len == 0) ? sizeof(ROUNDUP_TYPE) : ROUNDUP(sa->sa_len);
#else  /* !HAVE_STRUCT_SOCKADDR_SA_LEN */
        tlen = SAROUNDUP(sap);
#endif /* !HAVE_STRUCT_SOCKADDR_SA_LEN */

        if (copylen > 0 && dest != NULL && sdl->sdl_family == AF_LINK) {
                if (copylen > IFNAMSIZ) {
                        zlog_warn(
                                "%s: destination buffer too small (%zu vs %d)",
                                __func__, copylen, IFNAMSIZ);
                        memcpy(dest, sdl->sdl_data, IFNAMSIZ);
                        dest[IFNAMSIZ] = 0;
                        *destlen = IFNAMSIZ;
                } else {
                        memcpy(dest, sdl->sdl_data, copylen);
                        dest[copylen] = 0;
                        *destlen = copylen;
                }
        } else
                *destlen = 0;

        return tlen;
}

const char *rtatostr(unsigned int flags, char *buf, size_t buflen)
{
        const char *flagstr, *bufstart;
        int bit, wlen;
        char ustr[32];

        /* Hold the pointer to the buffer beginning. */
        bufstart = buf;

        for (bit = 1; bit; bit <<= 1) {
                if ((flags & bit) == 0)
                        continue;

                switch (bit) {
                case RTA_DST:
                        flagstr = "DST";
                        break;
                case RTA_GATEWAY:
                        flagstr = "GATEWAY";
                        break;
                case RTA_NETMASK:
                        flagstr = "NETMASK";
                        break;
#ifdef RTA_GENMASK
                case RTA_GENMASK:
                        flagstr = "GENMASK";
                        break;
#endif /* RTA_GENMASK */
                case RTA_IFP:
                        flagstr = "IFP";
                        break;
                case RTA_IFA:
                        flagstr = "IFA";
                        break;
#ifdef RTA_AUTHOR
                case RTA_AUTHOR:
                        flagstr = "AUTHOR";
                        break;
#endif /* RTA_AUTHOR */
                case RTA_BRD:
                        flagstr = "BRD";
                        break;
#ifdef RTA_SRC
                case RTA_SRC:
                        flagstr = "SRC";
                        break;
#endif /* RTA_SRC */
#ifdef RTA_SRCMASK
                case RTA_SRCMASK:
                        flagstr = "SRCMASK";
                        break;
#endif /* RTA_SRCMASK */
#ifdef RTA_LABEL
                case RTA_LABEL:
                        flagstr = "LABEL";
                        break;
#endif /* RTA_LABEL */

                default:
                        snprintf(ustr, sizeof(ustr), "0x%x", bit);
                        flagstr = ustr;
                        break;
                }

                wlen = snprintf(buf, buflen, "%s,", flagstr);
                buf += wlen;
                buflen -= wlen;
        }

        /* Check for empty buffer. */
        if (bufstart != buf)
                buf--;

        /* Remove the last comma. */
        *buf = 0;

        return bufstart;
}

/* Dump routing table flag for debug purpose. */
static void rtm_flag_dump(int flag)
{
        const struct message *mes;
        static char buf[BUFSIZ];

        buf[0] = '\0';
        for (mes = rtm_flag_str; mes->key != 0; mes++) {
                if (mes->key & flag) {
                        strlcat(buf, mes->str, BUFSIZ);
                        strlcat(buf, " ", BUFSIZ);
                }
        }
        zlog_debug("Kernel: %s", buf);
}

#ifdef RTM_IFANNOUNCE
/* Interface adding function */
static int ifan_read(struct if_announcemsghdr *ifan)
{
        struct interface *ifp;
        struct vrf *vrf = vrf_lookup_by_id(VRF_DEFAULT);

        ifp = if_lookup_by_index(ifan->ifan_index, VRF_DEFAULT);

        if (ifp)
                assert((ifp->ifindex == ifan->ifan_index)
                       || (ifp->ifindex == IFINDEX_INTERNAL));

        if ((ifp == NULL) || ((ifp->ifindex == IFINDEX_INTERNAL)
                              && (ifan->ifan_what == IFAN_ARRIVAL))) {
                if (IS_ZEBRA_DEBUG_KERNEL)
                        zlog_debug(
                                "%s: creating interface for ifindex %d, name %s",
                                __func__, ifan->ifan_index, ifan->ifan_name);

                /* Create Interface */
                ifp = if_get_by_name(ifan->ifan_name, vrf);
                if_set_index(ifp, ifan->ifan_index);

                if_get_metric(ifp);
                if_add_update(ifp);
        } else if (ifp != NULL && ifan->ifan_what == IFAN_DEPARTURE)
                if_delete_update(ifp);

        if_get_flags(ifp);
        if_get_mtu(ifp);
        if_get_metric(ifp);

        if (IS_ZEBRA_DEBUG_KERNEL)
                zlog_debug("%s: interface %s index %d", __func__,
                           ifan->ifan_name, ifan->ifan_index);

        return 0;
}
#endif /* RTM_IFANNOUNCE */

#ifdef HAVE_BSD_IFI_LINK_STATE
/* BSD link detect translation */
static void bsd_linkdetect_translate(struct if_msghdr *ifm)
{
        if ((ifm->ifm_data.ifi_link_state >= LINK_STATE_UP)
            || (ifm->ifm_data.ifi_link_state == LINK_STATE_UNKNOWN))
                SET_FLAG(ifm->ifm_flags, IFF_RUNNING);
        else
                UNSET_FLAG(ifm->ifm_flags, IFF_RUNNING);
}
#endif /* HAVE_BSD_IFI_LINK_STATE */

static enum zebra_link_type sdl_to_zebra_link_type(unsigned int sdlt)
{
        switch (sdlt) {
        case IFT_ETHER:
                return ZEBRA_LLT_ETHER;
        case IFT_X25:
                return ZEBRA_LLT_X25;
        case IFT_FDDI:
                return ZEBRA_LLT_FDDI;
        case IFT_PPP:
                return ZEBRA_LLT_PPP;
        case IFT_LOOP:
                return ZEBRA_LLT_LOOPBACK;
        case IFT_SLIP:
                return ZEBRA_LLT_SLIP;
        case IFT_ARCNET:
                return ZEBRA_LLT_ARCNET;
        case IFT_ATM:
                return ZEBRA_LLT_ATM;
        case IFT_LOCALTALK:
                return ZEBRA_LLT_LOCALTLK;
        case IFT_HIPPI:
                return ZEBRA_LLT_HIPPI;
#ifdef IFT_IEEE1394
        case IFT_IEEE1394:
                return ZEBRA_LLT_IEEE1394;
#endif

        default:
                return ZEBRA_LLT_UNKNOWN;
        }
}

/*
 * Handle struct if_msghdr obtained from reading routing socket or
 * sysctl (from interface_list).  There may or may not be sockaddrs
 * present after the header.
 */
int ifm_read(struct if_msghdr *ifm)
{
        struct interface *ifp = NULL;
        struct sockaddr_dl *sdl = NULL;
        char ifname[IFNAMSIZ];
        short ifnlen = 0;
        int maskbit;
        caddr_t cp;
        char fbuf[64];
        struct vrf *vrf = vrf_lookup_by_id(VRF_DEFAULT);

        /* terminate ifname at head (for strnlen) and tail (for safety) */
        ifname[IFNAMSIZ - 1] = '\0';

        /* paranoia: sanity check structure */
        if (ifm->ifm_msglen < sizeof(struct if_msghdr)) {
                flog_err(EC_ZEBRA_NETLINK_LENGTH_ERROR,
                         "ifm_read: ifm->ifm_msglen %d too short\n",
                         ifm->ifm_msglen);
                return -1;
        }

        /*
         * Check for a sockaddr_dl following the message.  First, point to
         * where a socakddr might be if one follows the message.
         */
        cp = (void *)(ifm + 1);

#ifdef SUNOS_5
        /*
         * XXX This behavior should be narrowed to only the kernel versions
         * for which the structures returned do not match the headers.
         *
         * if_msghdr_t on 64 bit kernels in Solaris 9 and earlier versions
         * is 12 bytes larger than the 32 bit version.
         */
        if (((struct sockaddr *)cp)->sa_family == AF_UNSPEC)
                cp = cp + 12;
#endif

        /* Look up for RTA_IFP and skip others. */
        for (maskbit = 1; maskbit; maskbit <<= 1) {
                if ((maskbit & ifm->ifm_addrs) == 0)
                        continue;
                if (maskbit != RTA_IFP) {
                        cp += rta_get(cp, NULL, 0);
                        continue;
                }

                /* Save the pointer to the structure. */
                sdl = (struct sockaddr_dl *)cp;
                cp += rta_getsdlname(cp, ifname, &ifnlen);
        }

        if (IS_ZEBRA_DEBUG_KERNEL)
                zlog_debug("%s: sdl ifname %s addrs {%s}", __func__,
                           (ifnlen ? ifname : "(nil)"),
                           rtatostr(ifm->ifm_addrs, fbuf, sizeof(fbuf)));

        /*
         * Look up on ifindex first, because ifindices are the primary handle
         * for
         * interfaces across the user/kernel boundary, for most systems.  (Some
         * messages, such as up/down status changes on NetBSD, do not include a
         * sockaddr_dl).
         */
        if ((ifp = if_lookup_by_index(ifm->ifm_index, VRF_DEFAULT)) != NULL) {
                /* we have an ifp, verify that the name matches as some systems,
                 * eg Solaris, have a 1:many association of ifindex:ifname
                 * if they dont match, we dont have the correct ifp and should
                 * set it back to NULL to let next check do lookup by name
                 */
                if (ifnlen && (strncmp(ifp->name, ifname, IFNAMSIZ) != 0)) {
                        if (IS_ZEBRA_DEBUG_KERNEL)
                                zlog_debug(
                                        "%s: ifp name %s doesn't match sdl name %s",
                                        __func__, ifp->name, ifname);
                        ifp = NULL;
                }
        }

        /*
         * If we dont have an ifp, try looking up by name.  Particularly as some
         * systems (Solaris) have a 1:many mapping of ifindex:ifname - the
         * ifname
         * is therefore our unique handle to that interface.
         *
         * Interfaces specified in the configuration file for which the ifindex
         * has not been determined will have ifindex == IFINDEX_INTERNAL, and
         * such
         * interfaces are found by this search, and then their ifindex values
         * can
         * be filled in.
         */
        if ((ifp == NULL) && ifnlen)
                ifp = if_lookup_by_name(ifname, vrf);

        /*
         * If ifp still does not exist or has an invalid index
         * (IFINDEX_INTERNAL),
         * create or fill in an interface.
         */
        if ((ifp == NULL) || (ifp->ifindex == IFINDEX_INTERNAL)) {
                /*
                 * To create or fill in an interface, a sockaddr_dl (via
                 * RTA_IFP) is required.
                 */
                if (!ifnlen) {
                        zlog_debug("Interface index %d (new) missing ifname",
                                   ifm->ifm_index);
                        return -1;
                }

#ifndef RTM_IFANNOUNCE
                /* Down->Down interface should be ignored here.
                 * See further comment below.
                 */
                if (!CHECK_FLAG(ifm->ifm_flags, IFF_UP))
                        return 0;
#endif /* !RTM_IFANNOUNCE */

                if (ifp == NULL) {
                        /* Interface that zebra was not previously aware of, so
                         * create. */
                        ifp = if_create(ifname, vrf);
                        if (IS_ZEBRA_DEBUG_KERNEL)
                                zlog_debug("%s: creating ifp for ifindex %d",
                                           __func__, ifm->ifm_index);
                }

                if (IS_ZEBRA_DEBUG_KERNEL)
                        zlog_debug(
                                "%s: updated/created ifp, ifname %s, ifindex %d",
                                __func__, ifp->name, ifp->ifindex);
                /*
                 * Fill in newly created interface structure, or larval
                 * structure with ifindex IFINDEX_INTERNAL.
                 */
                if_set_index(ifp, ifm->ifm_index);

#ifdef HAVE_BSD_IFI_LINK_STATE /* translate BSD kernel msg for link-state */
                bsd_linkdetect_translate(ifm);
#endif /* HAVE_BSD_IFI_LINK_STATE */

                if_flags_update(ifp, ifm->ifm_flags);
#if defined(__bsdi__)
                if_kvm_get_mtu(ifp);
#else
                if_get_mtu(ifp);
#endif /* __bsdi__ */
                if_get_metric(ifp);

                /*
                 * XXX sockaddr_dl contents can be larger than the structure
                 * definition.  There are 2 big families here:
                 *  - BSD has sdl_len + sdl_data[16] + overruns sdl_data
                 *    we MUST use sdl_len here or we'll truncate data.
                 *  - Solaris has no sdl_len, but sdl_data[244]
                 *    presumably, it's not going to run past that, so sizeof()
                 *    is fine here.
                 * a nonzero ifnlen from rta_getsdlname() means sdl is valid
                 */
                ifp->ll_type = ZEBRA_LLT_UNKNOWN;
                ifp->hw_addr_len = 0;
                if (ifnlen) {
#ifdef HAVE_STRUCT_SOCKADDR_DL_SDL_LEN
                        memcpy(&((struct zebra_if *)ifp->info)->sdl, sdl,
                               sdl->sdl_len);
#else
                        memcpy(&((struct zebra_if *)ifp->info)->sdl, sdl,
                               sizeof(struct sockaddr_dl));
#endif /* HAVE_STRUCT_SOCKADDR_DL_SDL_LEN */

                        ifp->ll_type = sdl_to_zebra_link_type(sdl->sdl_type);
                        if (sdl->sdl_alen <= sizeof(ifp->hw_addr)) {
                                memcpy(ifp->hw_addr, LLADDR(sdl),
                                       sdl->sdl_alen);
                                ifp->hw_addr_len = sdl->sdl_alen;
                        }
                }

                if_add_update(ifp);
        } else
        /*
         * Interface structure exists.  Adjust stored flags from
         * notification.  If interface has up->down or down->up
         * transition, call state change routines (to adjust routes,
         * notify routing daemons, etc.).  (Other flag changes are stored
         * but apparently do not trigger action.)
         */
        {
                if (ifp->ifindex != ifm->ifm_index) {
                        zlog_debug(
                                "%s: index mismatch, ifname %s, ifp index %d, "
                                "ifm index %d",
                                __func__, ifp->name, ifp->ifindex,
                                ifm->ifm_index);
                        return -1;
                }

#ifdef HAVE_BSD_IFI_LINK_STATE /* translate BSD kernel msg for link-state */
                bsd_linkdetect_translate(ifm);
#endif /* HAVE_BSD_IFI_LINK_STATE */

                /* update flags and handle operative->inoperative transition, if
                 * any */
                if_flags_update(ifp, ifm->ifm_flags);

#ifndef RTM_IFANNOUNCE
                if (!if_is_up(ifp)) {
                        /* No RTM_IFANNOUNCE on this platform, so we can never
                         * distinguish between ~IFF_UP and delete. We must
                         * presume
                         * it has been deleted.
                         * Eg, Solaris will not notify us of unplumb.
                         *
                         * XXX: Fixme - this should be runtime detected
                         * So that a binary compiled on a system with IFANNOUNCE
                         * will still behave correctly if run on a platform
                         * without
                         */
                        if_delete_update(ifp);
                }
#endif /* RTM_IFANNOUNCE */
                if (if_is_up(ifp)) {
#if defined(__bsdi__)
                        if_kvm_get_mtu(ifp);
#else
                        if_get_mtu(ifp);
#endif /* __bsdi__ */
                        if_get_metric(ifp);
                }
        }

#ifdef HAVE_NET_RT_IFLIST
        ifp->stats = ifm->ifm_data;
#endif /* HAVE_NET_RT_IFLIST */
        ifp->speed = ifm->ifm_data.ifi_baudrate / 1000000;

        if (IS_ZEBRA_DEBUG_KERNEL)
                zlog_debug("%s: interface %s index %d", __func__, ifp->name,
                           ifp->ifindex);

        return 0;
}

/* Address read from struct ifa_msghdr. */
static void ifam_read_mesg(struct ifa_msghdr *ifm, union sockunion *addr,
                           union sockunion *mask, union sockunion *brd,
                           char *ifname, short *ifnlen)
{
        caddr_t pnt, end;
        union sockunion dst;
        union sockunion gateway;
        int maskbit;
        char fbuf[64];

        pnt = (caddr_t)(ifm + 1);
        end = ((caddr_t)ifm) + ifm->ifam_msglen;

        /* Be sure structure is cleared */
        memset(mask, 0, sizeof(union sockunion));
        memset(addr, 0, sizeof(union sockunion));
        memset(brd, 0, sizeof(union sockunion));
        memset(&dst, 0, sizeof(union sockunion));
        memset(&gateway, 0, sizeof(union sockunion));

        /* We fetch each socket variable into sockunion. */
        for (maskbit = 1; maskbit; maskbit <<= 1) {
                if ((maskbit & ifm->ifam_addrs) == 0)
                        continue;

                switch (maskbit) {
                case RTA_DST:
                        pnt += rta_get(pnt, &dst, sizeof(dst));
                        break;
                case RTA_GATEWAY:
                        pnt += rta_get(pnt, &gateway, sizeof(gateway));
                        break;
                case RTA_NETMASK:
                        pnt += rta_getattr(pnt, mask, sizeof(*mask));
                        break;
                case RTA_IFP:
                        pnt += rta_getsdlname(pnt, ifname, ifnlen);
                        break;
                case RTA_IFA:
                        pnt += rta_get(pnt, addr, sizeof(*addr));
                        break;
                case RTA_BRD:
                        pnt += rta_get(pnt, brd, sizeof(*brd));
                        break;

                default:
                        pnt += rta_get(pnt, NULL, 0);
                        break;
                }

                if (pnt > end) {
                        zlog_warn("%s: overflow detected (pnt:%p end:%p)",
                                  __func__, pnt, end);
                        break;
                }
        }

        if (IS_ZEBRA_DEBUG_KERNEL) {
                switch (sockunion_family(addr)) {
                case AF_INET:
                case AF_INET6: {
                        char buf[4][INET6_ADDRSTRLEN];
                        int masklen =
                                (sockunion_family(addr) == AF_INET)
                                        ? ip_masklen(mask->sin.sin_addr)
                                        : ip6_masklen(mask->sin6.sin6_addr);
                        zlog_debug(
                                "%s: ifindex %d, ifname %s, ifam_addrs {%s}, "
                                "ifam_flags 0x%x, addr %s/%d broad %s dst %s "
                                "gateway %s",
                                __func__, ifm->ifam_index,
                                (ifnlen ? ifname : "(nil)"),
                                rtatostr(ifm->ifam_addrs, fbuf, sizeof(fbuf)),
                                ifm->ifam_flags,
                                sockunion2str(addr, buf[0], sizeof(buf[0])),
                                masklen,
                                sockunion2str(brd, buf[1], sizeof(buf[1])),
                                sockunion2str(&dst, buf[2], sizeof(buf[2])),
                                sockunion2str(&gateway, buf[2],
                                              sizeof(buf[2])));
                } break;
                default:
                        zlog_debug("%s: ifindex %d, ifname %s, ifam_addrs {%s}",
                                   __func__, ifm->ifam_index,
                                   (ifnlen ? ifname : "(nil)"),
                                   rtatostr(ifm->ifam_addrs, fbuf,
                                            sizeof(fbuf)));
                        break;
                }
        }

        /* Assert read up end point matches to end point */
        pnt = (caddr_t)ROUNDUP((size_t)pnt);
        if (pnt != (caddr_t)ROUNDUP((size_t)end))
                zlog_debug("ifam_read() doesn't read all socket data");
}

/* Interface's address information get. */
int ifam_read(struct ifa_msghdr *ifam)
{
        struct interface *ifp = NULL;
        union sockunion addr, mask, brd;
        char ifname[INTERFACE_NAMSIZ];
        short ifnlen = 0;
        char isalias = 0;
        int flags = 0;

        ifname[0] = ifname[INTERFACE_NAMSIZ - 1] = '\0';

        /* Allocate and read address information. */
        ifam_read_mesg(ifam, &addr, &mask, &brd, ifname, &ifnlen);

        if ((ifp = if_lookup_by_index(ifam->ifam_index, VRF_DEFAULT)) == NULL) {
                flog_warn(EC_ZEBRA_UNKNOWN_INTERFACE,
                          "%s: no interface for ifname %s, index %d", __func__,
                          ifname, ifam->ifam_index);
                return -1;
        }

        if (ifnlen && strncmp(ifp->name, ifname, INTERFACE_NAMSIZ))
                isalias = 1;

        /* N.B. The info in ifa_msghdr does not tell us whether the RTA_BRD
           field contains a broadcast address or a peer address, so we are
           forced to
           rely upon the interface type. */
        if (if_is_pointopoint(ifp))
                SET_FLAG(flags, ZEBRA_IFA_PEER);

#if 0
  /* it might seem cute to grab the interface metric here, however
   * we're processing an address update message, and so some systems
   * (e.g. FBSD) dont bother to fill in ifam_metric. Disabled, but left
   * in deliberately, as comment.
   */
  ifp->metric = ifam->ifam_metric;
#endif

        /* Add connected address. */
        switch (sockunion_family(&addr)) {
        case AF_INET:
                if (ifam->ifam_type == RTM_NEWADDR)
                        connected_add_ipv4(ifp, flags, &addr.sin.sin_addr,
                                           ip_masklen(mask.sin.sin_addr),
                                           &brd.sin.sin_addr,
                                           (isalias ? ifname : NULL),
                                           METRIC_MAX);
                else
                        connected_delete_ipv4(ifp, flags, &addr.sin.sin_addr,
                                              ip_masklen(mask.sin.sin_addr),
                                              &brd.sin.sin_addr);
                break;
        case AF_INET6:
                /* Unset interface index from link-local address when IPv6 stack
                   is KAME. */
                if (IN6_IS_ADDR_LINKLOCAL(&addr.sin6.sin6_addr)) {
                        SET_IN6_LINKLOCAL_IFINDEX(addr.sin6.sin6_addr, 0);
                }

                if (ifam->ifam_type == RTM_NEWADDR)
                        connected_add_ipv6(ifp, flags, &addr.sin6.sin6_addr,
                                           NULL,
                                           ip6_masklen(mask.sin6.sin6_addr),
                                           (isalias ? ifname : NULL),
                                           METRIC_MAX);
                else
                        connected_delete_ipv6(ifp, &addr.sin6.sin6_addr, NULL,
                                              ip6_masklen(mask.sin6.sin6_addr));
                break;
        default:
                /* Unsupported family silently ignore... */
                break;
        }

        /* Check interface flag for implicit up of the interface. */
        if_refresh(ifp);

#ifdef SUNOS_5
        /* In addition to lacking IFANNOUNCE, on SUNOS IFF_UP is strange.
         * See comments for SUNOS_5 in interface.c::if_flags_mangle.
         *
         * Here we take care of case where the real IFF_UP was previously
         * unset (as kept in struct zebra_if.primary_state) and the mangled
         * IFF_UP (ie IFF_UP set || listcount(connected) has now transitioned
         * to unset due to the lost non-primary address having DELADDR'd.
         *
         * we must delete the interface, because in between here and next
         * event for this interface-name the administrator could unplumb
         * and replumb the interface.
         */
        if (!if_is_up(ifp))
                if_delete_update(ifp);
#endif /* SUNOS_5 */

        return 0;
}

/* Interface function for reading kernel routing table information. */
static int rtm_read_mesg(struct rt_msghdr *rtm, union sockunion *dest,
                         union sockunion *mask, union sockunion *gate,
                         char *ifname, short *ifnlen)
{
        caddr_t pnt, end;
        int maskbit;

        /* Pnt points out socket data start point. */
        pnt = (caddr_t)(rtm + 1);
        end = ((caddr_t)rtm) + rtm->rtm_msglen;

        /* rt_msghdr version check. */
        if (rtm->rtm_version != RTM_VERSION)
                flog_warn(EC_ZEBRA_RTM_VERSION_MISMATCH,
                          "Routing message version different %d should be %d."
                          "This may cause problem\n",
                          rtm->rtm_version, RTM_VERSION);

        /* Be sure structure is cleared */
        memset(dest, 0, sizeof(union sockunion));
        memset(gate, 0, sizeof(union sockunion));
        memset(mask, 0, sizeof(union sockunion));

        /* We fetch each socket variable into sockunion. */
        /* We fetch each socket variable into sockunion. */
        for (maskbit = 1; maskbit; maskbit <<= 1) {
                if ((maskbit & rtm->rtm_addrs) == 0)
                        continue;

                switch (maskbit) {
                case RTA_DST:
                        pnt += rta_get(pnt, dest, sizeof(*dest));
                        break;
                case RTA_GATEWAY:
                        pnt += rta_get(pnt, gate, sizeof(*gate));
                        break;
                case RTA_NETMASK:
                        pnt += rta_getattr(pnt, mask, sizeof(*mask));
                        break;
                case RTA_IFP:
                        pnt += rta_getsdlname(pnt, ifname, ifnlen);
                        break;

                default:
                        pnt += rta_get(pnt, NULL, 0);
                        break;
                }

                if (pnt > end) {
                        zlog_warn("%s: overflow detected (pnt:%p end:%p)",
                                  __func__, pnt, end);
                        break;
                }
        }

        /* If there is netmask information set it's family same as
           destination family*/
        if (rtm->rtm_addrs & RTA_NETMASK)
                mask->sa.sa_family = dest->sa.sa_family;

        /* Assert read up to the end of pointer. */
        if (pnt != end)
                zlog_debug("rtm_read() doesn't read all socket data.");

        return rtm->rtm_flags;
}

void rtm_read(struct rt_msghdr *rtm)
{
        int flags;
        uint8_t zebra_flags;
        union sockunion dest, mask, gate;
        char ifname[INTERFACE_NAMSIZ + 1];
        short ifnlen = 0;
        struct nexthop nh;
        struct prefix p;
        ifindex_t ifindex = 0;
        afi_t afi;
        char fbuf[64];

        zebra_flags = 0;

        /* Read destination and netmask and gateway from rtm message
           structure. */
        flags = rtm_read_mesg(rtm, &dest, &mask, &gate, ifname, &ifnlen);
        if (!(flags & RTF_DONE))
                return;
        if (IS_ZEBRA_DEBUG_KERNEL)
                zlog_debug("%s: got rtm of type %d (%s) addrs {%s}", __func__,
                           rtm->rtm_type,
                           lookup_msg(rtm_type_str, rtm->rtm_type, NULL),
                           rtatostr(rtm->rtm_addrs, fbuf, sizeof(fbuf)));

#ifdef RTF_CLONED /*bsdi, netbsd 1.6*/
        if (flags & RTF_CLONED)
                return;
#endif
#ifdef RTF_WASCLONED /*freebsd*/
        if (flags & RTF_WASCLONED)
                return;
#endif

        if ((rtm->rtm_type == RTM_ADD || rtm->rtm_type == RTM_CHANGE)
            && !(flags & RTF_UP))
                return;

        /* This is connected route. */
        if (!(flags & RTF_GATEWAY))
                return;

        if (flags & RTF_PROTO1)
                SET_FLAG(zebra_flags, ZEBRA_FLAG_SELFROUTE);

        memset(&nh, 0, sizeof(nh));

        nh.vrf_id = VRF_DEFAULT;
        /* This is a reject or blackhole route */
        if (flags & RTF_REJECT) {
                nh.type = NEXTHOP_TYPE_BLACKHOLE;
                nh.bh_type = BLACKHOLE_REJECT;
        } else if (flags & RTF_BLACKHOLE) {
                nh.type = NEXTHOP_TYPE_BLACKHOLE;
                nh.bh_type = BLACKHOLE_NULL;
        }

        /*
         * Ignore our own messages.
         */
        if (rtm->rtm_type != RTM_GET && rtm->rtm_pid == pid)
                return;

        if (dest.sa.sa_family == AF_INET) {
                afi = AFI_IP;
                p.family = AF_INET;
                p.u.prefix4 = dest.sin.sin_addr;
                if (flags & RTF_HOST)
                        p.prefixlen = IPV4_MAX_PREFIXLEN;
                else
                        p.prefixlen = ip_masklen(mask.sin.sin_addr);

                if (!nh.type) {
                        nh.type = NEXTHOP_TYPE_IPV4;
                        nh.gate.ipv4 = gate.sin.sin_addr;
                }
        } else if (dest.sa.sa_family == AF_INET6) {
                afi = AFI_IP6;
                p.family = AF_INET6;
                p.u.prefix6 = dest.sin6.sin6_addr;
                if (flags & RTF_HOST)
                        p.prefixlen = IPV6_MAX_PREFIXLEN;
                else
                        p.prefixlen = ip6_masklen(mask.sin6.sin6_addr);

#ifdef KAME
                if (IN6_IS_ADDR_LINKLOCAL(&gate.sin6.sin6_addr)) {
                        ifindex = IN6_LINKLOCAL_IFINDEX(gate.sin6.sin6_addr);
                        SET_IN6_LINKLOCAL_IFINDEX(gate.sin6.sin6_addr, 0);
                }
#endif /* KAME */

                if (!nh.type) {
                        nh.type = ifindex ? NEXTHOP_TYPE_IPV6_IFINDEX
                                          : NEXTHOP_TYPE_IPV6;
                        nh.gate.ipv6 = gate.sin6.sin6_addr;
                        nh.ifindex = ifindex;
                }
        } else
                return;

        /*
         * CHANGE: delete the old prefix, we have no further information
         * to specify the route really
         */
        if (rtm->rtm_type == RTM_CHANGE)
                rib_delete(afi, SAFI_UNICAST, VRF_DEFAULT, ZEBRA_ROUTE_KERNEL,
                           0, zebra_flags, &p, NULL, NULL, RT_TABLE_MAIN,
                           0, 0, true);
        if (rtm->rtm_type == RTM_GET || rtm->rtm_type == RTM_ADD
            || rtm->rtm_type == RTM_CHANGE)
                rib_add(afi, SAFI_UNICAST, VRF_DEFAULT, ZEBRA_ROUTE_KERNEL, 0,
                        zebra_flags, &p, NULL, &nh, RT_TABLE_MAIN, 0, 0, 0, 0);
        else
                rib_delete(afi, SAFI_UNICAST, VRF_DEFAULT, ZEBRA_ROUTE_KERNEL,
                           0, zebra_flags, &p, NULL, &nh, RT_TABLE_MAIN,
                           0, 0, true);
}

/* Interface function for the kernel routing table updates.  Support
 * for RTM_CHANGE will be needed.
 * Exported only for rt_socket.c
 */
int rtm_write(int message, union sockunion *dest, union sockunion *mask,
              union sockunion *gate, union sockunion *mpls, unsigned int index,
              enum blackhole_type bh_type, int metric)
{
        int ret;
        caddr_t pnt;
        struct interface *ifp;

        /* Sequencial number of routing message. */
        static int msg_seq = 0;

        /* Struct of rt_msghdr and buffer for storing socket's data. */
        struct {
                struct rt_msghdr rtm;
                char buf[512];
        } msg;

        if (dplane_routing_sock < 0)
                return ZEBRA_ERR_EPERM;

        /* Clear and set rt_msghdr values */
        memset(&msg, 0, sizeof(struct rt_msghdr));
        msg.rtm.rtm_version = RTM_VERSION;
        msg.rtm.rtm_type = message;
        msg.rtm.rtm_seq = msg_seq++;
        msg.rtm.rtm_addrs = RTA_DST;
        msg.rtm.rtm_addrs |= RTA_GATEWAY;
        msg.rtm.rtm_flags = RTF_UP;
#ifdef __OpenBSD__
        msg.rtm.rtm_flags |= RTF_MPATH;
        msg.rtm.rtm_fmask = RTF_MPLS;
#endif
        msg.rtm.rtm_index = index;

        if (metric != 0) {
                msg.rtm.rtm_rmx.rmx_hopcount = metric;
                msg.rtm.rtm_inits |= RTV_HOPCOUNT;
        }

        ifp = if_lookup_by_index(index, VRF_DEFAULT);

        if (gate && (message == RTM_ADD || message == RTM_CHANGE))
                msg.rtm.rtm_flags |= RTF_GATEWAY;

/* When RTF_CLONING is unavailable on BSD, should we set some
 * other flag instead?
 */
#ifdef RTF_CLONING
        if (!gate && (message == RTM_ADD || message == RTM_CHANGE) && ifp
            && (ifp->flags & IFF_POINTOPOINT) == 0)
                msg.rtm.rtm_flags |= RTF_CLONING;
#endif /* RTF_CLONING */

        /* If no protocol specific gateway is specified, use link
           address for gateway. */
        if (!gate) {
                if (!ifp) {
                        char dest_buf[INET_ADDRSTRLEN] = "NULL",
                             mask_buf[INET_ADDRSTRLEN] = "255.255.255.255";
                        if (dest)
                                inet_ntop(AF_INET, &dest->sin.sin_addr,
                                          dest_buf, INET_ADDRSTRLEN);
                        if (mask)
                                inet_ntop(AF_INET, &mask->sin.sin_addr,
                                          mask_buf, INET_ADDRSTRLEN);
                        flog_warn(
                                EC_ZEBRA_RTM_NO_GATEWAY,
                                "%s: %s/%s: gate == NULL and no gateway found for ifindex %d",
                                __func__, dest_buf, mask_buf, index);
                        return -1;
                }
                gate = (union sockunion *)&((struct zebra_if *)ifp->info)->sdl;
        }

        if (mask)
                msg.rtm.rtm_addrs |= RTA_NETMASK;
        else if (message == RTM_ADD || message == RTM_CHANGE)
                msg.rtm.rtm_flags |= RTF_HOST;

#ifdef __OpenBSD__
        if (mpls) {
                msg.rtm.rtm_addrs |= RTA_SRC;
                msg.rtm.rtm_flags |= RTF_MPLS;

                if (mpls->smpls.smpls_label
                    != htonl(MPLS_LABEL_IMPLICIT_NULL << MPLS_LABEL_OFFSET))
                        msg.rtm.rtm_mpls = MPLS_OP_PUSH;
        }
#endif

        /* Tagging route with flags */
        msg.rtm.rtm_flags |= (RTF_PROTO1);

        switch (bh_type) {
        case BLACKHOLE_UNSPEC:
                break;
        case BLACKHOLE_REJECT:
                msg.rtm.rtm_flags |= RTF_REJECT;
                break;
        default:
                msg.rtm.rtm_flags |= RTF_BLACKHOLE;
                break;
        }


#define SOCKADDRSET(X, R)                                                      \
        if (msg.rtm.rtm_addrs & (R)) {                                         \
                int len = SAROUNDUP(X);                                        \
                memcpy(pnt, (caddr_t)(X), len);                                \
                pnt += len;                                                    \
        }

        pnt = (caddr_t)msg.buf;

        /* Write each socket data into rtm message buffer */
        SOCKADDRSET(dest, RTA_DST);
        SOCKADDRSET(gate, RTA_GATEWAY);
        SOCKADDRSET(mask, RTA_NETMASK);
#ifdef __OpenBSD__
        SOCKADDRSET(mpls, RTA_SRC);
#endif

        msg.rtm.rtm_msglen = pnt - (caddr_t)&msg;

        ret = write(dplane_routing_sock, &msg, msg.rtm.rtm_msglen);

        if (ret != msg.rtm.rtm_msglen) {
                if (errno == EEXIST)
                        return ZEBRA_ERR_RTEXIST;
                if (errno == ENETUNREACH)
                        return ZEBRA_ERR_RTUNREACH;
                if (errno == ESRCH)
                        return ZEBRA_ERR_RTNOEXIST;

                flog_err_sys(EC_LIB_SOCKET, "%s: write : %s (%d)", __func__,
                             safe_strerror(errno), errno);
                return ZEBRA_ERR_KERNEL;
        }
        return ZEBRA_ERR_NOERROR;
}


#include "thread.h"
#include "zebra/zserv.h"

/* For debug purpose. */
static void rtmsg_debug(struct rt_msghdr *rtm)
{
        char fbuf[64];

        zlog_debug("Kernel: Len: %d Type: %s", rtm->rtm_msglen,
                   lookup_msg(rtm_type_str, rtm->rtm_type, NULL));
        rtm_flag_dump(rtm->rtm_flags);
        zlog_debug("Kernel: message seq %d", rtm->rtm_seq);
        zlog_debug("Kernel: pid %lld, rtm_addrs {%s}", (long long)rtm->rtm_pid,
                   rtatostr(rtm->rtm_addrs, fbuf, sizeof(fbuf)));
}

/* This is pretty gross, better suggestions welcome -- mhandler */
#ifndef RTAX_MAX
#ifdef RTA_NUMBITS
#define RTAX_MAX        RTA_NUMBITS
#else
#define RTAX_MAX        8
#endif /* RTA_NUMBITS */
#endif /* RTAX_MAX */

/* Kernel routing table and interface updates via routing socket. */
static int kernel_read(struct thread *thread)
{
        int sock;
        int nbytes;
        struct rt_msghdr *rtm;

        /*
         * This must be big enough for any message the kernel might send.
         * Rather than determining how many sockaddrs of what size might be
         * in each particular message, just use RTAX_MAX of sockaddr_storage
         * for each.  Note that the sockaddrs must be after each message
         * definition, or rather after whichever happens to be the largest,
         * since the buffer needs to be big enough for a message and the
         * sockaddrs together.
         */
        union {
                /* Routing information. */
                struct {
                        struct rt_msghdr rtm;
                        struct sockaddr_storage addr[RTAX_MAX];
                } r;

                /* Interface information. */
                struct {
                        struct if_msghdr ifm;
                        struct sockaddr_storage addr[RTAX_MAX];
                } im;

                /* Interface address information. */
                struct {
                        struct ifa_msghdr ifa;
                        struct sockaddr_storage addr[RTAX_MAX];
                } ia;

#ifdef RTM_IFANNOUNCE
                /* Interface arrival/departure */
                struct {
                        struct if_announcemsghdr ifan;
                        struct sockaddr_storage addr[RTAX_MAX];
                } ian;
#endif /* RTM_IFANNOUNCE */

        } buf;

        /* Fetch routing socket. */
        sock = THREAD_FD(thread);

        nbytes = read(sock, &buf, sizeof buf);

        if (nbytes <= 0) {
                if (nbytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN)
                        flog_err_sys(EC_LIB_SOCKET, "routing socket error: %s",
                                     safe_strerror(errno));
                return 0;
        }

        thread_add_read(zrouter.master, kernel_read, NULL, sock, NULL);

        if (IS_ZEBRA_DEBUG_KERNEL)
                rtmsg_debug(&buf.r.rtm);

        rtm = &buf.r.rtm;

        /*
         * Ensure that we didn't drop any data, so that processing routines
         * can assume they have the whole message.
         */
        if (rtm->rtm_msglen != nbytes) {
                zlog_debug(
                        "kernel_read: rtm->rtm_msglen %d, nbytes %d, type %d\n",
                        rtm->rtm_msglen, nbytes, rtm->rtm_type);
                return -1;
        }

        switch (rtm->rtm_type) {
        case RTM_ADD:
        case RTM_DELETE:
        case RTM_CHANGE:
                rtm_read(rtm);
                break;
        case RTM_IFINFO:
                ifm_read(&buf.im.ifm);
                break;
        case RTM_NEWADDR:
        case RTM_DELADDR:
                ifam_read(&buf.ia.ifa);
                break;
#ifdef RTM_IFANNOUNCE
        case RTM_IFANNOUNCE:
                ifan_read(&buf.ian.ifan);
                break;
#endif /* RTM_IFANNOUNCE */
        default:
                if (IS_ZEBRA_DEBUG_KERNEL)
                        zlog_debug("Unprocessed RTM_type: %d", rtm->rtm_type);
                break;
        }
        return 0;
}

/* Make routing socket. */
static void routing_socket(struct zebra_ns *zns)
{
        frr_elevate_privs(&zserv_privs) {
                routing_sock = ns_socket(AF_ROUTE, SOCK_RAW, 0, zns->ns_id);

                dplane_routing_sock =
                        ns_socket(AF_ROUTE, SOCK_RAW, 0, zns->ns_id);
        }

        if (routing_sock < 0) {
                flog_err_sys(EC_LIB_SOCKET, "Can't init kernel routing socket");
                return;
        }

        if (dplane_routing_sock < 0) {
                flog_err_sys(EC_LIB_SOCKET,
                             "Can't init kernel dataplane routing socket");
                return;
        }

        /* XXX: Socket should be NONBLOCK, however as we currently
         * discard failed writes, this will lead to inconsistencies.
         * For now, socket must be blocking.
         */
        /*if (fcntl (routing_sock, F_SETFL, O_NONBLOCK) < 0)
          zlog_warn ("Can't set O_NONBLOCK to routing socket");*/

        /* kernel_read needs rewrite. */
        thread_add_read(zrouter.master, kernel_read, NULL, routing_sock, NULL);
}

/* Exported interface function.  This function simply calls
   routing_socket (). */
void kernel_init(struct zebra_ns *zns)
{
        routing_socket(zns);
}

void kernel_terminate(struct zebra_ns *zns, bool complete)
{
        return;
}

#endif /* !HAVE_NETLINK */