lib: dont decode more nexthops than we can handle

[mirror_frr.git] / lib / if.c

/*
 * Interface functions.
 * Copyright (C) 1997, 98 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>

#include "linklist.h"
#include "vector.h"
#include "lib_errors.h"
#include "vty.h"
#include "command.h"
#include "vrf.h"
#include "if.h"
#include "sockunion.h"
#include "prefix.h"
#include "memory.h"
#include "table.h"
#include "buffer.h"
#include "log.h"
#include "northbound_cli.h"
#ifndef VTYSH_EXTRACT_PL
#include "lib/if_clippy.c"
#endif

DEFINE_MTYPE_STATIC(LIB, IF, "Interface")
DEFINE_MTYPE_STATIC(LIB, CONNECTED, "Connected")
DEFINE_MTYPE_STATIC(LIB, NBR_CONNECTED, "Neighbor Connected")
DEFINE_MTYPE(LIB, CONNECTED_LABEL, "Connected interface label")
DEFINE_MTYPE_STATIC(LIB, IF_LINK_PARAMS, "Informational Link Parameters")

static struct interface *if_lookup_by_ifindex(ifindex_t ifindex,
                                              vrf_id_t vrf_id);
static int if_cmp_func(const struct interface *, const struct interface *);
static int if_cmp_index_func(const struct interface *ifp1,
                             const struct interface *ifp2);
RB_GENERATE(if_name_head, interface, name_entry, if_cmp_func);
RB_GENERATE(if_index_head, interface, index_entry, if_cmp_index_func);

DEFINE_QOBJ_TYPE(interface)

DEFINE_HOOK(if_add, (struct interface * ifp), (ifp))
DEFINE_KOOH(if_del, (struct interface * ifp), (ifp))

static struct interface_master{
        int (*create_hook)(struct interface *ifp);
        int (*up_hook)(struct interface *ifp);
        int (*down_hook)(struct interface *ifp);
        int (*destroy_hook)(struct interface *ifp);
} ifp_master = { 0, };

/* Compare interface names, returning an integer greater than, equal to, or
 * less than 0, (following the strcmp convention), according to the
 * relationship between ifp1 and ifp2.  Interface names consist of an
 * alphabetic prefix and a numeric suffix.  The primary sort key is
 * lexicographic by name, and then numeric by number.  No number sorts
 * before all numbers.  Examples: de0 < de1, de100 < fxp0 < xl0, devpty <
 * devpty0, de0 < del0
 */
int if_cmp_name_func(const char *p1, const char *p2)
{
        unsigned int l1, l2;
        long int x1, x2;
        int res;

        while (*p1 && *p2) {
                /* look up to any number */
                l1 = strcspn(p1, "0123456789");
                l2 = strcspn(p2, "0123456789");

                /* name lengths are different -> compare names */
                if (l1 != l2)
                        return (strcmp(p1, p2));

                /* Note that this relies on all numbers being less than all
                 * letters, so
                 * that de0 < del0.
                 */
                res = strncmp(p1, p2, l1);

                /* names are different -> compare them */
                if (res)
                        return res;

                /* with identical name part, go to numeric part */
                p1 += l1;
                p2 += l1;

                if (!*p1 && !*p2)
                        return 0;
                if (!*p1)
                        return -1;
                if (!*p2)
                        return 1;

                x1 = strtol(p1, (char **)&p1, 10);
                x2 = strtol(p2, (char **)&p2, 10);

                /* let's compare numbers now */
                if (x1 < x2)
                        return -1;
                if (x1 > x2)
                        return 1;

                /* numbers were equal, lets do it again..
                (it happens with name like "eth123.456:789") */
        }
        if (*p1)
                return 1;
        if (*p2)
                return -1;
        return 0;
}

static int if_cmp_func(const struct interface *ifp1,
                       const struct interface *ifp2)
{
        return if_cmp_name_func(ifp1->name, ifp2->name);
}

static int if_cmp_index_func(const struct interface *ifp1,
                             const struct interface *ifp2)
{
        return ifp1->ifindex - ifp2->ifindex;
}

static void ifp_connected_free(void *arg)
{
        struct connected *c = arg;

        connected_free(&c);
}

/* Create new interface structure. */
static struct interface *if_new(vrf_id_t vrf_id)
{
        struct interface *ifp;

        ifp = XCALLOC(MTYPE_IF, sizeof(struct interface));

        ifp->ifindex = IFINDEX_INTERNAL;
        ifp->name[0] = '\0';

        ifp->vrf_id = vrf_id;

        ifp->connected = list_new();
        ifp->connected->del = ifp_connected_free;

        ifp->nbr_connected = list_new();
        ifp->nbr_connected->del = (void (*)(void *))nbr_connected_free;

        /* Enable Link-detection by default */
        SET_FLAG(ifp->status, ZEBRA_INTERFACE_LINKDETECTION);

        QOBJ_REG(ifp, interface);
        return ifp;
}

void if_new_via_zapi(struct interface *ifp)
{
        if (ifp_master.create_hook)
                (*ifp_master.create_hook)(ifp);
}

void if_destroy_via_zapi(struct interface *ifp)
{
        if (ifp_master.destroy_hook)
                (*ifp_master.destroy_hook)(ifp);

        if_set_index(ifp, IFINDEX_INTERNAL);
        if (!ifp->configured)
                if_delete(&ifp);
}

void if_up_via_zapi(struct interface *ifp)
{
        if (ifp_master.up_hook)
                (*ifp_master.up_hook)(ifp);
}

void if_down_via_zapi(struct interface *ifp)
{
        if (ifp_master.down_hook)
                (*ifp_master.down_hook)(ifp);
}

struct interface *if_create_name(const char *name, vrf_id_t vrf_id)
{
        struct interface *ifp;

        ifp = if_new(vrf_id);

        if_set_name(ifp, name);

        hook_call(if_add, ifp);
        return ifp;
}

struct interface *if_create_ifindex(ifindex_t ifindex, vrf_id_t vrf_id)
{
        struct interface *ifp;

        ifp = if_new(vrf_id);

        if_set_index(ifp, ifindex);

        hook_call(if_add, ifp);
        return ifp;
}

/* Create new interface structure. */
void if_update_to_new_vrf(struct interface *ifp, vrf_id_t vrf_id)
{
        struct vrf *old_vrf, *vrf;

        /* remove interface from old master vrf list */
        old_vrf = vrf_lookup_by_id(ifp->vrf_id);
        if (old_vrf) {
                if (ifp->name[0] != '\0')
                        IFNAME_RB_REMOVE(old_vrf, ifp);

                if (ifp->ifindex != IFINDEX_INTERNAL)
                        IFINDEX_RB_REMOVE(old_vrf, ifp);
        }

        ifp->vrf_id = vrf_id;
        vrf = vrf_get(ifp->vrf_id, NULL);

        if (ifp->name[0] != '\0')
                IFNAME_RB_INSERT(vrf, ifp);

        if (ifp->ifindex != IFINDEX_INTERNAL)
                IFINDEX_RB_INSERT(vrf, ifp);

        /*
         * HACK: Change the interface VRF in the running configuration directly,
         * bypassing the northbound layer. This is necessary to avoid deleting
         * the interface and readding it in the new VRF, which would have
         * several implications.
         */
        if (yang_module_find("frr-interface")) {
                struct lyd_node *if_dnode;

                if_dnode = yang_dnode_get(
                        running_config->dnode,
                        "/frr-interface:lib/interface[name='%s'][vrf='%s']/vrf",
                        ifp->name, old_vrf->name);
                if (if_dnode) {
                        nb_running_unset_entry(if_dnode->parent);
                        yang_dnode_change_leaf(if_dnode, vrf->name);
                        nb_running_set_entry(if_dnode->parent, ifp);
                        running_config->version++;
                }
        }
}


/* Delete interface structure. */
void if_delete_retain(struct interface *ifp)
{
        hook_call(if_del, ifp);
        QOBJ_UNREG(ifp);

        /* Free connected address list */
        list_delete_all_node(ifp->connected);

        /* Free connected nbr address list */
        list_delete_all_node(ifp->nbr_connected);
}

/* Delete and free interface structure. */
void if_delete(struct interface **ifp)
{
        struct interface *ptr = *ifp;
        struct vrf *vrf;

        vrf = vrf_lookup_by_id(ptr->vrf_id);
        assert(vrf);

        IFNAME_RB_REMOVE(vrf, ptr);
        if (ptr->ifindex != IFINDEX_INTERNAL)
                IFINDEX_RB_REMOVE(vrf, ptr);

        if_delete_retain(ptr);

        list_delete(&ptr->connected);
        list_delete(&ptr->nbr_connected);

        if_link_params_free(ptr);

        XFREE(MTYPE_TMP, ptr->desc);

        XFREE(MTYPE_IF, ptr);
        *ifp = NULL;
}

/* Used only internally to check within VRF only */
static struct interface *if_lookup_by_ifindex(ifindex_t ifindex,
                                              vrf_id_t vrf_id)
{
        struct vrf *vrf;
        struct interface if_tmp;

        vrf = vrf_lookup_by_id(vrf_id);
        if (!vrf)
                return NULL;

        if_tmp.ifindex = ifindex;
        return RB_FIND(if_index_head, &vrf->ifaces_by_index, &if_tmp);
}

/* Interface existance check by index. */
struct interface *if_lookup_by_index(ifindex_t ifindex, vrf_id_t vrf_id)
{
        switch (vrf_get_backend()) {
        case VRF_BACKEND_UNKNOWN:
        case VRF_BACKEND_NETNS:
                return(if_lookup_by_ifindex(ifindex, vrf_id));
        case VRF_BACKEND_VRF_LITE:
                return(if_lookup_by_index_all_vrf(ifindex));
        }
        return NULL;
}

const char *ifindex2ifname(ifindex_t ifindex, vrf_id_t vrf_id)
{
        struct interface *ifp;

        return ((ifp = if_lookup_by_index(ifindex, vrf_id)) != NULL)
                       ? ifp->name
                       : "unknown";
}

ifindex_t ifname2ifindex(const char *name, vrf_id_t vrf_id)
{
        struct interface *ifp;

        return ((ifp = if_lookup_by_name(name, vrf_id)) != NULL)
                       ? ifp->ifindex
                       : IFINDEX_INTERNAL;
}

/* Interface existance check by interface name. */
struct interface *if_lookup_by_name(const char *name, vrf_id_t vrf_id)
{
        struct vrf *vrf = vrf_lookup_by_id(vrf_id);
        struct interface if_tmp;

        if (!vrf || !name
            || strnlen(name, INTERFACE_NAMSIZ) == INTERFACE_NAMSIZ)
                return NULL;

        strlcpy(if_tmp.name, name, sizeof(if_tmp.name));
        return RB_FIND(if_name_head, &vrf->ifaces_by_name, &if_tmp);
}

struct interface *if_lookup_by_name_all_vrf(const char *name)
{
        struct vrf *vrf;
        struct interface *ifp;

        if (!name || strnlen(name, INTERFACE_NAMSIZ) == INTERFACE_NAMSIZ)
                return NULL;

        RB_FOREACH (vrf, vrf_id_head, &vrfs_by_id) {
                ifp = if_lookup_by_name(name, vrf->vrf_id);
                if (ifp)
                        return ifp;
        }

        return NULL;
}

struct interface *if_lookup_by_index_all_vrf(ifindex_t ifindex)
{
        struct vrf *vrf;
        struct interface *ifp;

        if (ifindex == IFINDEX_INTERNAL)
                return NULL;

        RB_FOREACH (vrf, vrf_id_head, &vrfs_by_id) {
                ifp = if_lookup_by_ifindex(ifindex, vrf->vrf_id);
                if (ifp)
                        return ifp;
        }

        return NULL;
}

/* Lookup interface by IP address. */
struct interface *if_lookup_exact_address(void *src, int family,
                                          vrf_id_t vrf_id)
{
        struct vrf *vrf = vrf_lookup_by_id(vrf_id);
        struct listnode *cnode;
        struct interface *ifp;
        struct prefix *p;
        struct connected *c;

        FOR_ALL_INTERFACES (vrf, ifp) {
                for (ALL_LIST_ELEMENTS_RO(ifp->connected, cnode, c)) {
                        p = c->address;

                        if (p && (p->family == family)) {
                                if (family == AF_INET) {
                                        if (IPV4_ADDR_SAME(
                                                    &p->u.prefix4,
                                                    (struct in_addr *)src))
                                                return ifp;
                                } else if (family == AF_INET6) {
                                        if (IPV6_ADDR_SAME(
                                                    &p->u.prefix6,
                                                    (struct in6_addr *)src))
                                                return ifp;
                                }
                        }
                }
        }
        return NULL;
}

/* Lookup interface by IP address. */
struct connected *if_lookup_address(void *matchaddr, int family,
                                    vrf_id_t vrf_id)
{
        struct vrf *vrf = vrf_lookup_by_id(vrf_id);
        struct prefix addr;
        int bestlen = 0;
        struct listnode *cnode;
        struct interface *ifp;
        struct connected *c;
        struct connected *match;

        if (family == AF_INET) {
                addr.family = AF_INET;
                addr.u.prefix4 = *((struct in_addr *)matchaddr);
                addr.prefixlen = IPV4_MAX_BITLEN;
        } else if (family == AF_INET6) {
                addr.family = AF_INET6;
                addr.u.prefix6 = *((struct in6_addr *)matchaddr);
                addr.prefixlen = IPV6_MAX_BITLEN;
        }

        match = NULL;

        FOR_ALL_INTERFACES (vrf, ifp) {
                for (ALL_LIST_ELEMENTS_RO(ifp->connected, cnode, c)) {
                        if (c->address && (c->address->family == AF_INET)
                            && prefix_match(CONNECTED_PREFIX(c), &addr)
                            && (c->address->prefixlen > bestlen)) {
                                bestlen = c->address->prefixlen;
                                match = c;
                        }
                }
        }
        return match;
}

/* Lookup interface by prefix */
struct interface *if_lookup_prefix(struct prefix *prefix, vrf_id_t vrf_id)
{
        struct vrf *vrf = vrf_lookup_by_id(vrf_id);
        struct listnode *cnode;
        struct interface *ifp;
        struct connected *c;

        FOR_ALL_INTERFACES (vrf, ifp) {
                for (ALL_LIST_ELEMENTS_RO(ifp->connected, cnode, c)) {
                        if (prefix_cmp(c->address, prefix) == 0) {
                                return ifp;
                        }
                }
        }
        return NULL;
}

size_t if_lookup_by_hwaddr(const uint8_t *hw_addr, size_t addrsz,
                           struct interface ***result, vrf_id_t vrf_id)
{
        struct vrf *vrf = vrf_lookup_by_id(vrf_id);

        struct list *rs = list_new();
        struct interface *ifp;

        FOR_ALL_INTERFACES (vrf, ifp) {
                if (ifp->hw_addr_len == (int)addrsz
                    && !memcmp(hw_addr, ifp->hw_addr, addrsz))
                        listnode_add(rs, ifp);
        }

        if (rs->count) {
                *result = XCALLOC(MTYPE_TMP,
                                  sizeof(struct interface *) * rs->count);
                list_to_array(rs, (void **)*result, rs->count);
        }

        int count = rs->count;

        list_delete(&rs);

        return count;
}


/* Get interface by name if given name interface doesn't exist create
   one. */
struct interface *if_get_by_name(const char *name, vrf_id_t vrf_id)
{
        struct interface *ifp;

        switch (vrf_get_backend()) {
        case VRF_BACKEND_UNKNOWN:
        case VRF_BACKEND_NETNS:
                ifp = if_lookup_by_name(name, vrf_id);
                if (ifp)
                        return ifp;
                return if_create_name(name, vrf_id);
        case VRF_BACKEND_VRF_LITE:
                ifp = if_lookup_by_name_all_vrf(name);
                if (ifp) {
                        if (ifp->vrf_id == vrf_id)
                                return ifp;
                        /* If it came from the kernel or by way of zclient,
                         * believe it and update the ifp accordingly.
                         */
                        if_update_to_new_vrf(ifp, vrf_id);
                        return ifp;
                }
                return if_create_name(name, vrf_id);
        }

        return NULL;
}

struct interface *if_get_by_ifindex(ifindex_t ifindex, vrf_id_t vrf_id)
{
        struct interface *ifp;

        switch (vrf_get_backend()) {
        case VRF_BACKEND_UNKNOWN:
        case VRF_BACKEND_NETNS:
                ifp = if_lookup_by_ifindex(ifindex, vrf_id);
                if (ifp)
                        return ifp;
                return if_create_ifindex(ifindex, vrf_id);
        case VRF_BACKEND_VRF_LITE:
                ifp = if_lookup_by_index_all_vrf(ifindex);
                if (ifp) {
                        if (ifp->vrf_id == vrf_id)
                                return ifp;
                        /* If it came from the kernel or by way of zclient,
                         * believe it and update the ifp accordingly.
                         */
                        if_update_to_new_vrf(ifp, vrf_id);
                        return ifp;
                }
                return if_create_ifindex(ifindex, vrf_id);
        }

        return NULL;
}

void if_set_index(struct interface *ifp, ifindex_t ifindex)
{
        struct vrf *vrf;

        vrf = vrf_get(ifp->vrf_id, NULL);
        assert(vrf);

        if (ifp->ifindex == ifindex)
                return;

        if (ifp->ifindex != IFINDEX_INTERNAL)
                IFINDEX_RB_REMOVE(vrf, ifp);

        ifp->ifindex = ifindex;

        if (ifp->ifindex != IFINDEX_INTERNAL)
                IFINDEX_RB_INSERT(vrf, ifp)
}

void if_set_name(struct interface *ifp, const char *name)
{
        struct vrf *vrf;

        vrf = vrf_get(ifp->vrf_id, NULL);
        assert(vrf);

        if (if_cmp_name_func(ifp->name, name) == 0)
                return;

        if (ifp->name[0] != '\0')
                IFNAME_RB_REMOVE(vrf, ifp);

        strlcpy(ifp->name, name, sizeof(ifp->name));

        if (ifp->name[0] != '\0')
                IFNAME_RB_INSERT(vrf, ifp);
}

/* Does interface up ? */
int if_is_up(const struct interface *ifp)
{
        return ifp->flags & IFF_UP;
}

/* Is interface running? */
int if_is_running(const struct interface *ifp)
{
        return ifp->flags & IFF_RUNNING;
}

/* Is the interface operative, eg. either UP & RUNNING
   or UP & !ZEBRA_INTERFACE_LINK_DETECTION and
   if ptm checking is enabled, then ptm check has passed */
int if_is_operative(const struct interface *ifp)
{
        return ((ifp->flags & IFF_UP)
                && (((ifp->flags & IFF_RUNNING)
                     && (ifp->ptm_status || !ifp->ptm_enable))
                    || !CHECK_FLAG(ifp->status,
                                   ZEBRA_INTERFACE_LINKDETECTION)));
}

/* Is the interface operative, eg. either UP & RUNNING
   or UP & !ZEBRA_INTERFACE_LINK_DETECTION, without PTM check */
int if_is_no_ptm_operative(const struct interface *ifp)
{
        return ((ifp->flags & IFF_UP)
                && ((ifp->flags & IFF_RUNNING)
                    || !CHECK_FLAG(ifp->status,
                                   ZEBRA_INTERFACE_LINKDETECTION)));
}

/* Is this loopback interface ? */
int if_is_loopback(const struct interface *ifp)
{
        /* XXX: Do this better, eg what if IFF_WHATEVER means X on platform M
         * but Y on platform N?
         */
        return (ifp->flags & (IFF_LOOPBACK | IFF_NOXMIT | IFF_VIRTUAL));
}

/* Check interface is VRF */
int if_is_vrf(const struct interface *ifp)
{
        return CHECK_FLAG(ifp->status, ZEBRA_INTERFACE_VRF_LOOPBACK);
}

bool if_is_loopback_or_vrf(const struct interface *ifp)
{
        if (if_is_loopback(ifp) || if_is_vrf(ifp))
                return true;

        return false;
}

/* Does this interface support broadcast ? */
int if_is_broadcast(const struct interface *ifp)
{
        return ifp->flags & IFF_BROADCAST;
}

/* Does this interface support broadcast ? */
int if_is_pointopoint(const struct interface *ifp)
{
        return ifp->flags & IFF_POINTOPOINT;
}

/* Does this interface support multicast ? */
int if_is_multicast(const struct interface *ifp)
{
        return ifp->flags & IFF_MULTICAST;
}

/* Printout flag information into log */
const char *if_flag_dump(unsigned long flag)
{
        int separator = 0;
        static char logbuf[BUFSIZ];

#define IFF_OUT_LOG(X, STR)                                                    \
        if (flag & (X)) {                                                      \
                if (separator)                                                 \
                        strlcat(logbuf, ",", sizeof(logbuf));                  \
                else                                                           \
                        separator = 1;                                         \
                strlcat(logbuf, STR, sizeof(logbuf));                          \
        }

        strlcpy(logbuf, "<", BUFSIZ);
        IFF_OUT_LOG(IFF_UP, "UP");
        IFF_OUT_LOG(IFF_BROADCAST, "BROADCAST");
        IFF_OUT_LOG(IFF_DEBUG, "DEBUG");
        IFF_OUT_LOG(IFF_LOOPBACK, "LOOPBACK");
        IFF_OUT_LOG(IFF_POINTOPOINT, "POINTOPOINT");
        IFF_OUT_LOG(IFF_NOTRAILERS, "NOTRAILERS");
        IFF_OUT_LOG(IFF_RUNNING, "RUNNING");
        IFF_OUT_LOG(IFF_NOARP, "NOARP");
        IFF_OUT_LOG(IFF_PROMISC, "PROMISC");
        IFF_OUT_LOG(IFF_ALLMULTI, "ALLMULTI");
        IFF_OUT_LOG(IFF_OACTIVE, "OACTIVE");
        IFF_OUT_LOG(IFF_SIMPLEX, "SIMPLEX");
        IFF_OUT_LOG(IFF_LINK0, "LINK0");
        IFF_OUT_LOG(IFF_LINK1, "LINK1");
        IFF_OUT_LOG(IFF_LINK2, "LINK2");
        IFF_OUT_LOG(IFF_MULTICAST, "MULTICAST");
        IFF_OUT_LOG(IFF_NOXMIT, "NOXMIT");
        IFF_OUT_LOG(IFF_NORTEXCH, "NORTEXCH");
        IFF_OUT_LOG(IFF_VIRTUAL, "VIRTUAL");
        IFF_OUT_LOG(IFF_IPV4, "IPv4");
        IFF_OUT_LOG(IFF_IPV6, "IPv6");

        strlcat(logbuf, ">", sizeof(logbuf));

        return logbuf;
#undef IFF_OUT_LOG
}

/* For debugging */
static void if_dump(const struct interface *ifp)
{
        struct listnode *node;
        struct connected *c __attribute__((unused));

        for (ALL_LIST_ELEMENTS_RO(ifp->connected, node, c))
                zlog_info(
                        "Interface %s vrf %u index %d metric %d mtu %d "
                        "mtu6 %d %s",
                        ifp->name, ifp->vrf_id, ifp->ifindex, ifp->metric,
                        ifp->mtu, ifp->mtu6, if_flag_dump(ifp->flags));
}

/* Interface printing for all interface. */
void if_dump_all(void)
{
        struct vrf *vrf;
        void *ifp;

        RB_FOREACH (vrf, vrf_id_head, &vrfs_by_id)
                FOR_ALL_INTERFACES (vrf, ifp)
                        if_dump(ifp);
}

#ifdef SUNOS_5
/* Need to handle upgrade from SUNWzebra to Quagga. SUNWzebra created
 * a seperate struct interface for each logical interface, so config
 * file may be full of 'interface fooX:Y'. Solaris however does not
 * expose logical interfaces via PF_ROUTE, so trying to track logical
 * interfaces can be fruitless, for that reason Quagga only tracks
 * the primary IP interface.
 *
 * We try accomodate SUNWzebra by:
 * - looking up the interface name, to see whether it exists, if so
 *   its useable
 *   - for protocol daemons, this could only because zebra told us of
 *     the interface
 *   - for zebra, only because it learnt from kernel
 * - if not:
 *   - search the name to see if it contains a sub-ipif / logical interface
 *     seperator, the ':' char. If it does:
 *     - text up to that char must be the primary name - get that name.
 *     if not:
 *     - no idea, just get the name in its entirety.
 */
static struct interface *if_sunwzebra_get(const char *name, vrf_id_t vrf_id)
{
        struct interface *ifp;
        char *cp;

        if ((ifp = if_lookup_by_name(name, vrf_id)) != NULL)
                return ifp;

        /* hunt the primary interface name... */
        cp = strchr(name, ':');
        if (cp)
                *cp = '\0';

        return if_get_by_name(name, vrf_id);
}
#endif /* SUNOS_5 */

#if 0
/* For debug purpose. */
DEFUN (show_address,
       show_address_cmd,
       "show address [vrf NAME]",
       SHOW_STR
       "address\n"
       VRF_CMD_HELP_STR)
{
  int idx_vrf = 3;
  struct listnode *node;
  struct interface *ifp;
  struct connected *ifc;
  struct prefix *p;
  vrf_id_t vrf_id = VRF_DEFAULT;

  if (argc > 2)
    VRF_GET_ID (vrf_id, argv[idx_vrf]->arg);

  FOR_ALL_INTERFACES (vrf, ifp)
    {
      for (ALL_LIST_ELEMENTS_RO (ifp->connected, node, ifc))
        {
          p = ifc->address;

          if (p->family == AF_INET)
            vty_out (vty, "%s/%d\n", inet_ntoa (p->u.prefix4), p->prefixlen);
        }
    }
  return CMD_SUCCESS;
}

DEFUN (show_address_vrf_all,
       show_address_vrf_all_cmd,
       "show address vrf all",
       SHOW_STR
       "address\n"
       VRF_ALL_CMD_HELP_STR)
{
  struct vrf *vrf;
  struct listnode *node;
  struct interface *ifp;
  struct connected *ifc;
  struct prefix *p;

  RB_FOREACH (vrf, vrf_name_head, &vrfs_by_name)
    {
      if (RB_EMPTY (if_name_head, &vrf->ifaces_by_name))
        continue;

      vty_out (vty, "\nVRF %u\n\n", vrf->vrf_id);

      FOR_ALL_INTERFACES (vrf, ifp)
        {
          for (ALL_LIST_ELEMENTS_RO (ifp->connected, node, ifc))
            {
              p = ifc->address;

              if (p->family == AF_INET)
                vty_out (vty, "%s/%d\n", inet_ntoa (p->u.prefix4), p->prefixlen);
            }
        }
    }
  return CMD_SUCCESS;
}
#endif

/* Allocate connected structure. */
struct connected *connected_new(void)
{
        return XCALLOC(MTYPE_CONNECTED, sizeof(struct connected));
}

/* Allocate nbr connected structure. */
struct nbr_connected *nbr_connected_new(void)
{
        return XCALLOC(MTYPE_NBR_CONNECTED, sizeof(struct nbr_connected));
}

/* Free connected structure. */
void connected_free(struct connected **connected)
{
        struct connected *ptr = *connected;

        if (ptr->address)
                prefix_free(&ptr->address);

        if (ptr->destination)
                prefix_free(&ptr->destination);

        XFREE(MTYPE_CONNECTED_LABEL, ptr->label);

        XFREE(MTYPE_CONNECTED, ptr);
        *connected = NULL;
}

/* Free nbr connected structure. */
void nbr_connected_free(struct nbr_connected *connected)
{
        if (connected->address)
                prefix_free(&connected->address);

        XFREE(MTYPE_NBR_CONNECTED, connected);
}

/* If same interface nbr address already exists... */
struct nbr_connected *nbr_connected_check(struct interface *ifp,
                                          struct prefix *p)
{
        struct nbr_connected *ifc;
        struct listnode *node;

        for (ALL_LIST_ELEMENTS_RO(ifp->nbr_connected, node, ifc))
                if (prefix_same(ifc->address, p))
                        return ifc;

        return NULL;
}

/* Print if_addr structure. */
static void __attribute__((unused))
connected_log(struct connected *connected, char *str)
{
        struct prefix *p;
        struct interface *ifp;
        char logbuf[BUFSIZ];
        char buf[BUFSIZ];

        ifp = connected->ifp;
        p = connected->address;

        snprintf(logbuf, BUFSIZ, "%s interface %s vrf %u %s %s/%d ", str,
                 ifp->name, ifp->vrf_id, prefix_family_str(p),
                 inet_ntop(p->family, &p->u.prefix, buf, BUFSIZ), p->prefixlen);

        p = connected->destination;
        if (p) {
                strncat(logbuf, inet_ntop(p->family, &p->u.prefix, buf, BUFSIZ),
                        BUFSIZ - strlen(logbuf));
        }
        zlog_info("%s", logbuf);
}

/* Print if_addr structure. */
static void __attribute__((unused))
nbr_connected_log(struct nbr_connected *connected, char *str)
{
        struct prefix *p;
        struct interface *ifp;
        char logbuf[BUFSIZ];
        char buf[BUFSIZ];

        ifp = connected->ifp;
        p = connected->address;

        snprintf(logbuf, BUFSIZ, "%s interface %s %s %s/%d ", str, ifp->name,
                 prefix_family_str(p),
                 inet_ntop(p->family, &p->u.prefix, buf, BUFSIZ), p->prefixlen);

        zlog_info("%s", logbuf);
}

/* If two connected address has same prefix return 1. */
static int connected_same_prefix(struct prefix *p1, struct prefix *p2)
{
        if (p1->family == p2->family) {
                if (p1->family == AF_INET
                    && IPV4_ADDR_SAME(&p1->u.prefix4, &p2->u.prefix4))
                        return 1;
                if (p1->family == AF_INET6
                    && IPV6_ADDR_SAME(&p1->u.prefix6, &p2->u.prefix6))
                        return 1;
        }
        return 0;
}

/* count the number of connected addresses that are in the given family */
unsigned int connected_count_by_family(struct interface *ifp, int family)
{
        struct listnode *cnode;
        struct connected *connected;
        unsigned int cnt = 0;

        for (ALL_LIST_ELEMENTS_RO(ifp->connected, cnode, connected))
                if (connected->address->family == family)
                        cnt++;

        return cnt;
}

struct connected *connected_lookup_prefix_exact(struct interface *ifp,
                                                struct prefix *p)
{
        struct listnode *node;
        struct listnode *next;
        struct connected *ifc;

        for (node = listhead(ifp->connected); node; node = next) {
                ifc = listgetdata(node);
                next = node->next;

                if (connected_same_prefix(ifc->address, p))
                        return ifc;
        }
        return NULL;
}

struct connected *connected_delete_by_prefix(struct interface *ifp,
                                             struct prefix *p)
{
        struct listnode *node;
        struct listnode *next;
        struct connected *ifc;

        /* In case of same prefix come, replace it with new one. */
        for (node = listhead(ifp->connected); node; node = next) {
                ifc = listgetdata(node);
                next = node->next;

                if (connected_same_prefix(ifc->address, p)) {
                        listnode_delete(ifp->connected, ifc);
                        return ifc;
                }
        }
        return NULL;
}

/* Find the address on our side that will be used when packets
   are sent to dst. */
struct connected *connected_lookup_prefix(struct interface *ifp,
                                          struct prefix *addr)
{
        struct listnode *cnode;
        struct connected *c;
        struct connected *match;

        match = NULL;

        for (ALL_LIST_ELEMENTS_RO(ifp->connected, cnode, c)) {
                if (c->address && (c->address->family == addr->family)
                    && prefix_match(CONNECTED_PREFIX(c), addr)
                    && (!match
                        || (c->address->prefixlen > match->address->prefixlen)))
                        match = c;
        }
        return match;
}

struct connected *connected_add_by_prefix(struct interface *ifp,
                                          struct prefix *p,
                                          struct prefix *destination)
{
        struct connected *ifc;

        /* Allocate new connected address. */
        ifc = connected_new();
        ifc->ifp = ifp;

        /* Fetch interface address */
        ifc->address = prefix_new();
        memcpy(ifc->address, p, sizeof(struct prefix));

        /* Fetch dest address */
        if (destination) {
                ifc->destination = prefix_new();
                memcpy(ifc->destination, destination, sizeof(struct prefix));
        }

        /* Add connected address to the interface. */
        listnode_add(ifp->connected, ifc);
        return ifc;
}

struct connected *connected_get_linklocal(struct interface *ifp)
{
        struct listnode *n;
        struct connected *c = NULL;

        for (ALL_LIST_ELEMENTS_RO(ifp->connected, n, c)) {
                if (c->address->family == AF_INET6
                    && IN6_IS_ADDR_LINKLOCAL(&c->address->u.prefix6))
                        break;
        }
        return c;
}

#if 0  /* this route_table of struct connected's is unused                     \
        * however, it would be good to use a route_table rather than           \
        * a list..                                                             \
        */
/* Interface looking up by interface's address. */
/* Interface's IPv4 address reverse lookup table. */
struct route_table *ifaddr_ipv4_table;
/* struct route_table *ifaddr_ipv6_table; */

static void
ifaddr_ipv4_add (struct in_addr *ifaddr, struct interface *ifp)
{
  struct route_node *rn;
  struct prefix_ipv4 p;

  p.family = AF_INET;
  p.prefixlen = IPV4_MAX_PREFIXLEN;
  p.prefix = *ifaddr;

  rn = route_node_get (ifaddr_ipv4_table, (struct prefix *) &p);
  if (rn)
    {
      route_unlock_node (rn);
      zlog_info ("ifaddr_ipv4_add(): address %s is already added",
                 inet_ntoa (*ifaddr));
      return;
    }
  rn->info = ifp;
}

static void
ifaddr_ipv4_delete (struct in_addr *ifaddr, struct interface *ifp)
{
  struct route_node *rn;
  struct prefix_ipv4 p;

  p.family = AF_INET;
  p.prefixlen = IPV4_MAX_PREFIXLEN;
  p.prefix = *ifaddr;

  rn = route_node_lookup (ifaddr_ipv4_table, (struct prefix *) &p);
  if (! rn)
    {
      zlog_info ("ifaddr_ipv4_delete(): can't find address %s",
                 inet_ntoa (*ifaddr));
      return;
    }
  rn->info = NULL;
  route_unlock_node (rn);
  route_unlock_node (rn);
}

/* Lookup interface by interface's IP address or interface index. */
static struct interface *
ifaddr_ipv4_lookup (struct in_addr *addr, ifindex_t ifindex)
{
  struct prefix_ipv4 p;
  struct route_node *rn;
  struct interface *ifp;

  if (addr)
    {
      p.family = AF_INET;
      p.prefixlen = IPV4_MAX_PREFIXLEN;
      p.prefix = *addr;

      rn = route_node_lookup (ifaddr_ipv4_table, (struct prefix *) &p);
      if (! rn)
        return NULL;

      ifp = rn->info;
      route_unlock_node (rn);
      return ifp;
    }
  else
    return if_lookup_by_index(ifindex, VRF_DEFAULT);
}
#endif /* ifaddr_ipv4_table */

void if_terminate(struct vrf *vrf)
{
        struct interface *ifp;

        while (!RB_EMPTY(if_name_head, &vrf->ifaces_by_name)) {
                ifp = RB_ROOT(if_name_head, &vrf->ifaces_by_name);

                if (ifp->node) {
                        ifp->node->info = NULL;
                        route_unlock_node(ifp->node);
                }
                if_delete(&ifp);
        }
}

const char *if_link_type_str(enum zebra_link_type llt)
{
        switch (llt) {
#define llts(T,S) case (T): return (S)
                llts(ZEBRA_LLT_UNKNOWN, "Unknown");
                llts(ZEBRA_LLT_ETHER, "Ethernet");
                llts(ZEBRA_LLT_EETHER, "Experimental Ethernet");
                llts(ZEBRA_LLT_AX25, "AX.25 Level 2");
                llts(ZEBRA_LLT_PRONET, "PROnet token ring");
                llts(ZEBRA_LLT_IEEE802, "IEEE 802.2 Ethernet/TR/TB");
                llts(ZEBRA_LLT_ARCNET, "ARCnet");
                llts(ZEBRA_LLT_APPLETLK, "AppleTalk");
                llts(ZEBRA_LLT_DLCI, "Frame Relay DLCI");
                llts(ZEBRA_LLT_ATM, "ATM");
                llts(ZEBRA_LLT_METRICOM, "Metricom STRIP");
                llts(ZEBRA_LLT_IEEE1394, "IEEE 1394 IPv4");
                llts(ZEBRA_LLT_EUI64, "EUI-64");
                llts(ZEBRA_LLT_INFINIBAND, "InfiniBand");
                llts(ZEBRA_LLT_SLIP, "SLIP");
                llts(ZEBRA_LLT_CSLIP, "Compressed SLIP");
                llts(ZEBRA_LLT_SLIP6, "SLIPv6");
                llts(ZEBRA_LLT_CSLIP6, "Compressed SLIPv6");
                llts(ZEBRA_LLT_ROSE, "ROSE packet radio");
                llts(ZEBRA_LLT_X25, "CCITT X.25");
                llts(ZEBRA_LLT_PPP, "PPP");
                llts(ZEBRA_LLT_CHDLC, "Cisco HDLC");
                llts(ZEBRA_LLT_RAWHDLC, "Raw HDLC");
                llts(ZEBRA_LLT_LAPB, "LAPB");
                llts(ZEBRA_LLT_IPIP, "IPIP Tunnel");
                llts(ZEBRA_LLT_IPIP6, "IPIP6 Tunnel");
                llts(ZEBRA_LLT_FRAD, "FRAD");
                llts(ZEBRA_LLT_SKIP, "SKIP vif");
                llts(ZEBRA_LLT_LOOPBACK, "Loopback");
                llts(ZEBRA_LLT_LOCALTLK, "Localtalk");
                llts(ZEBRA_LLT_FDDI, "FDDI");
                llts(ZEBRA_LLT_SIT, "IPv6-in-IPv4 SIT");
                llts(ZEBRA_LLT_IPDDP, "IP-in-DDP tunnel");
                llts(ZEBRA_LLT_IPGRE, "GRE over IP");
                llts(ZEBRA_LLT_PIMREG, "PIMSM registration");
                llts(ZEBRA_LLT_HIPPI, "HiPPI");
                llts(ZEBRA_LLT_IRDA, "IrDA");
                llts(ZEBRA_LLT_FCPP, "Fibre-Channel PtP");
                llts(ZEBRA_LLT_FCAL, "Fibre-Channel Arbitrated Loop");
                llts(ZEBRA_LLT_FCPL, "Fibre-Channel Public Loop");
                llts(ZEBRA_LLT_FCFABRIC, "Fibre-Channel Fabric");
                llts(ZEBRA_LLT_IEEE802_TR, "IEEE 802.2 Token Ring");
                llts(ZEBRA_LLT_IEEE80211, "IEEE 802.11");
                llts(ZEBRA_LLT_IEEE80211_RADIOTAP, "IEEE 802.11 Radiotap");
                llts(ZEBRA_LLT_IEEE802154, "IEEE 802.15.4");
                llts(ZEBRA_LLT_IEEE802154_PHY, "IEEE 802.15.4 Phy");
        default:
                flog_err(EC_LIB_DEVELOPMENT, "Unknown value %d", llt);
                return "Unknown type!";
#undef llts
        }
        return NULL;
}

struct if_link_params *if_link_params_get(struct interface *ifp)
{
        int i;

        if (ifp->link_params != NULL)
                return ifp->link_params;

        struct if_link_params *iflp =
                XCALLOC(MTYPE_IF_LINK_PARAMS, sizeof(struct if_link_params));
        if (iflp == NULL)
                return NULL;

        /* Set TE metric equal to standard metric */
        iflp->te_metric = ifp->metric;

        /* Compute default bandwidth based on interface */
        iflp->default_bw =
                ((ifp->bandwidth ? ifp->bandwidth : DEFAULT_BANDWIDTH)
                 * TE_KILO_BIT / TE_BYTE);

        /* Set Max, Reservable and Unreserved Bandwidth */
        iflp->max_bw = iflp->default_bw;
        iflp->max_rsv_bw = iflp->default_bw;
        for (i = 0; i < MAX_CLASS_TYPE; i++)
                iflp->unrsv_bw[i] = iflp->default_bw;

        /* Update Link parameters status */
        iflp->lp_status =
                LP_TE_METRIC | LP_MAX_BW | LP_MAX_RSV_BW | LP_UNRSV_BW;

        /* Finally attach newly created Link Parameters */
        ifp->link_params = iflp;

        return iflp;
}

void if_link_params_free(struct interface *ifp)
{
        if (ifp->link_params == NULL)
                return;
        XFREE(MTYPE_IF_LINK_PARAMS, ifp->link_params);
        ifp->link_params = NULL;
}

/* ----------- CLI commands ----------- */

/*
 * XPath: /frr-interface:lib/interface
 */
DEFPY_NOSH (interface,
       interface_cmd,
       "interface IFNAME [vrf NAME$vrf_name]",
       "Select an interface to configure\n"
       "Interface's name\n"
       VRF_CMD_HELP_STR)
{
        char xpath_list[XPATH_MAXLEN];
        vrf_id_t vrf_id;
        struct interface *ifp;
        int ret;

        if (!vrf_name)
                vrf_name = VRF_DEFAULT_NAME;

        /*
         * This command requires special handling to maintain backward
         * compatibility. If a VRF name is not specified, it means we're willing
         * to accept any interface with the given name on any VRF. If no
         * interface is found, then a new one should be created on the default
         * VRF.
         */
        VRF_GET_ID(vrf_id, vrf_name, false);
        ifp = if_lookup_by_name_all_vrf(ifname);
        if (ifp && ifp->vrf_id != vrf_id) {
                struct vrf *vrf;

                /*
                 * Special case 1: a VRF name was specified, but the found
                 * interface is associated to different VRF. Reject the command.
                 */
                if (vrf_id != VRF_DEFAULT) {
                        vty_out(vty, "%% interface %s not in %s vrf\n", ifname,
                                vrf_name);
                        return CMD_WARNING_CONFIG_FAILED;
                }

                /*
                 * Special case 2: a VRF name was *not* specified, and the found
                 * interface is associated to a VRF other than the default one.
                 * Update vrf_id and vrf_name to account for that.
                 */
                vrf = vrf_lookup_by_id(ifp->vrf_id);
                assert(vrf);
                vrf_id = ifp->vrf_id;
                vrf_name = vrf->name;
        }

        snprintf(xpath_list, sizeof(xpath_list),
                 "/frr-interface:lib/interface[name='%s'][vrf='%s']", ifname,
                 vrf_name);

        nb_cli_enqueue_change(vty, ".", NB_OP_CREATE, NULL);
        ret = nb_cli_apply_changes(vty, xpath_list);
        if (ret == CMD_SUCCESS) {
                VTY_PUSH_XPATH(INTERFACE_NODE, xpath_list);

                /*
                 * For backward compatibility with old commands we still need
                 * to use the qobj infrastructure. This can be removed once
                 * all interface-level commands are converted to the new
                 * northbound model.
                 */
                ifp = if_lookup_by_name(ifname, vrf_id);
                if (ifp)
                        VTY_PUSH_CONTEXT(INTERFACE_NODE, ifp);
        }

        return ret;
}

DEFPY (no_interface,
       no_interface_cmd,
       "no interface IFNAME [vrf NAME$vrf_name]",
       NO_STR
       "Delete a pseudo interface's configuration\n"
       "Interface's name\n"
       VRF_CMD_HELP_STR)
{
        if (!vrf_name)
                vrf_name = VRF_DEFAULT_NAME;

        nb_cli_enqueue_change(vty, ".", NB_OP_DESTROY, NULL);

        return nb_cli_apply_changes(
                vty, "/frr-interface:lib/interface[name='%s'][vrf='%s']",
                ifname, vrf_name);
}

static void cli_show_interface(struct vty *vty, struct lyd_node *dnode,
                        bool show_defaults)
{
        const char *vrf;

        vrf = yang_dnode_get_string(dnode, "./vrf");

        vty_out(vty, "!\n");
        vty_out(vty, "interface %s", yang_dnode_get_string(dnode, "./name"));
        if (!strmatch(vrf, VRF_DEFAULT_NAME))
                vty_out(vty, " vrf %s", vrf);
        vty_out(vty, "\n");
}

/*
 * XPath: /frr-interface:lib/interface/description
 */
DEFPY (interface_desc,
       interface_desc_cmd,
       "description LINE...",
       "Interface specific description\n"
       "Characters describing this interface\n")
{
        char *desc;
        int ret;

        desc = argv_concat(argv, argc, 1);
        nb_cli_enqueue_change(vty, "./description", NB_OP_MODIFY, desc);
        ret = nb_cli_apply_changes(vty, NULL);
        XFREE(MTYPE_TMP, desc);

        return ret;
}

DEFPY  (no_interface_desc,
        no_interface_desc_cmd,
        "no description",
        NO_STR
        "Interface specific description\n")
{
        nb_cli_enqueue_change(vty, "./description", NB_OP_DESTROY, NULL);

        return nb_cli_apply_changes(vty, NULL);
}

static void cli_show_interface_desc(struct vty *vty, struct lyd_node *dnode,
                             bool show_defaults)
{
        vty_out(vty, " description %s\n", yang_dnode_get_string(dnode, NULL));
}

/* Interface autocomplete. */
static void if_autocomplete(vector comps, struct cmd_token *token)
{
        struct interface *ifp;
        struct vrf *vrf;

        RB_FOREACH (vrf, vrf_name_head, &vrfs_by_name) {
                FOR_ALL_INTERFACES (vrf, ifp) {
                        vector_set(comps, XSTRDUP(MTYPE_COMPLETION, ifp->name));
                }
        }
}

static const struct cmd_variable_handler if_var_handlers[] = {
        {/* "interface NAME" */
         .varname = "interface",
         .completions = if_autocomplete},
        {.tokenname = "IFNAME", .completions = if_autocomplete},
        {.tokenname = "INTERFACE", .completions = if_autocomplete},
        {.completions = NULL}};

void if_cmd_init(void)
{
        cmd_variable_handler_register(if_var_handlers);

        install_element(CONFIG_NODE, &interface_cmd);
        install_element(CONFIG_NODE, &no_interface_cmd);

        install_default(INTERFACE_NODE);
        install_element(INTERFACE_NODE, &interface_desc_cmd);
        install_element(INTERFACE_NODE, &no_interface_desc_cmd);
}

void if_zapi_callbacks(int (*create)(struct interface *ifp),
                       int (*up)(struct interface *ifp),
                       int (*down)(struct interface *ifp),
                       int (*destroy)(struct interface *ifp))
{
        ifp_master.create_hook = create;
        ifp_master.up_hook = up;
        ifp_master.down_hook = down;
        ifp_master.destroy_hook = destroy;
}

/* ------- Northbound callbacks ------- */

/*
 * XPath: /frr-interface:lib/interface
 */
static int lib_interface_create(enum nb_event event,
                                const struct lyd_node *dnode,
                                union nb_resource *resource)
{
        const char *ifname;
        const char *vrfname;
        struct vrf *vrf;
        struct interface *ifp;

        ifname = yang_dnode_get_string(dnode, "./name");
        vrfname = yang_dnode_get_string(dnode, "./vrf");

        switch (event) {
        case NB_EV_VALIDATE:
                vrf = vrf_lookup_by_name(vrfname);
                if (!vrf) {
                        zlog_warn("%s: VRF %s doesn't exist", __func__,
                                  vrfname);
                        return NB_ERR_VALIDATION;
                }
                if (vrf->vrf_id == VRF_UNKNOWN) {
                        zlog_warn("%s: VRF %s is not active", __func__,
                                  vrf->name);
                        return NB_ERR_VALIDATION;
                }

                /* if VRF is netns or not yet known - init for instance
                 * then assumption is that passed config is exact
                 * then the user intent was not to use an other iface
                 */
                if (vrf_get_backend() == VRF_BACKEND_VRF_LITE) {
                        ifp = if_lookup_by_name_all_vrf(ifname);
                        if (ifp && ifp->vrf_id != vrf->vrf_id) {
                                zlog_warn(
                                        "%s: interface %s already exists in another VRF",
                                        __func__, ifp->name);
                                return NB_ERR_VALIDATION;
                        }
                }
                break;
        case NB_EV_PREPARE:
        case NB_EV_ABORT:
                break;
        case NB_EV_APPLY:
                vrf = vrf_lookup_by_name(vrfname);
                assert(vrf);
#ifdef SUNOS_5
                ifp = if_sunwzebra_get(ifname, vrf->vrf_id);
#else
                ifp = if_get_by_name(ifname, vrf->vrf_id);
#endif /* SUNOS_5 */

                ifp->configured = true;
                nb_running_set_entry(dnode, ifp);
                break;
        }

        return NB_OK;
}

static int lib_interface_destroy(enum nb_event event,
                                 const struct lyd_node *dnode)
{
        struct interface *ifp;


        switch (event) {
        case NB_EV_VALIDATE:
                ifp = nb_running_get_entry(dnode, NULL, true);
                if (CHECK_FLAG(ifp->status, ZEBRA_INTERFACE_ACTIVE)) {
                        zlog_warn("%s: only inactive interfaces can be deleted",
                                  __func__);
                        return NB_ERR_VALIDATION;
                }
                break;
        case NB_EV_PREPARE:
        case NB_EV_ABORT:
                break;
        case NB_EV_APPLY:
                ifp = nb_running_unset_entry(dnode);

                ifp->configured = false;
                if_delete(&ifp);
                break;
        }

        return NB_OK;
}

/*
 * XPath: /frr-interface:lib/interface
 */
static const void *lib_interface_get_next(const void *parent_list_entry,
                                          const void *list_entry)
{
        struct vrf *vrf;
        struct interface *pif = (struct interface *)list_entry;

        if (list_entry == NULL) {
                vrf = RB_MIN(vrf_name_head, &vrfs_by_name);
                assert(vrf);
                pif = RB_MIN(if_name_head, &vrf->ifaces_by_name);
        } else {
                vrf = vrf_lookup_by_id(pif->vrf_id);
                pif = RB_NEXT(if_name_head, pif);
                /* if no more interfaces, switch to next vrf */
                while (pif == NULL) {
                        vrf = RB_NEXT(vrf_name_head, vrf);
                        if (!vrf)
                                return NULL;
                        pif = RB_MIN(if_name_head, &vrf->ifaces_by_name);
                }
        }

        return pif;
}

static int lib_interface_get_keys(const void *list_entry,
                                  struct yang_list_keys *keys)
{
        const struct interface *ifp = list_entry;

        struct vrf *vrf = vrf_lookup_by_id(ifp->vrf_id);

        assert(vrf);

        keys->num = 2;
        strlcpy(keys->key[0], ifp->name, sizeof(keys->key[0]));
        strlcpy(keys->key[1], vrf->name, sizeof(keys->key[1]));

        return NB_OK;
}

static const void *lib_interface_lookup_entry(const void *parent_list_entry,
                                              const struct yang_list_keys *keys)
{
        const char *ifname = keys->key[0];
        const char *vrfname = keys->key[1];
        struct vrf *vrf = vrf_lookup_by_name(vrfname);

        return vrf ? if_lookup_by_name(ifname, vrf->vrf_id) : NULL;
}

/*
 * XPath: /frr-interface:lib/interface/description
 */
static int lib_interface_description_modify(enum nb_event event,
                                            const struct lyd_node *dnode,
                                            union nb_resource *resource)
{
        struct interface *ifp;
        const char *description;

        if (event != NB_EV_APPLY)
                return NB_OK;

        ifp = nb_running_get_entry(dnode, NULL, true);
        XFREE(MTYPE_TMP, ifp->desc);
        description = yang_dnode_get_string(dnode, NULL);
        ifp->desc = XSTRDUP(MTYPE_TMP, description);

        return NB_OK;
}

static int lib_interface_description_destroy(enum nb_event event,
                                             const struct lyd_node *dnode)
{
        struct interface *ifp;

        if (event != NB_EV_APPLY)
                return NB_OK;

        ifp = nb_running_get_entry(dnode, NULL, true);
        XFREE(MTYPE_TMP, ifp->desc);

        return NB_OK;
}

/* clang-format off */

#if defined(__GNUC__) && ((__GNUC__ - 0) < 5) && !defined(__clang__)
/* gcc versions before 5.x miscalculate the size for structs with variable
 * length arrays (they just count it as size 0)
 */
struct frr_yang_module_info_size3 {
        /* YANG module name. */
        const char *name;

        /* Northbound callbacks. */
        const struct {
                /* Data path of this YANG node. */
                const char *xpath;

                /* Callbacks implemented for this node. */
                struct nb_callbacks cbs;

                /* Priority - lower priorities are processed first. */
                uint32_t priority;
        } nodes[3];
};

const struct frr_yang_module_info_size3 frr_interface_info_size3 asm("frr_interface_info") = {
#else
const struct frr_yang_module_info frr_interface_info = {
#endif
        .name = "frr-interface",
        .nodes = {
                {
                        .xpath = "/frr-interface:lib/interface",
                        .cbs = {
                                .create = lib_interface_create,
                                .destroy = lib_interface_destroy,
                                .cli_show = cli_show_interface,
                                .get_next = lib_interface_get_next,
                                .get_keys = lib_interface_get_keys,
                                .lookup_entry = lib_interface_lookup_entry,
                        },
                },
                {
                        .xpath = "/frr-interface:lib/interface/description",
                        .cbs = {
                                .modify = lib_interface_description_modify,
                                .destroy = lib_interface_description_destroy,
                                .cli_show = cli_show_interface_desc,
                        },
                },
                {
                        .xpath = NULL,
                },
        }
};