Merge pull request #8458 from opensourcerouting/xref-5424

[mirror_frr.git] / lib / vrf.c

/*
 * VRF functions.
 * Copyright (C) 2014 6WIND S.A.
 *
 * 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 "if.h"
#include "vrf.h"
#include "vrf_int.h"
#include "prefix.h"
#include "table.h"
#include "log.h"
#include "memory.h"
#include "command.h"
#include "ns.h"
#include "privs.h"
#include "nexthop_group.h"
#include "lib_errors.h"
#include "northbound.h"
#include "northbound_cli.h"

/* default VRF name value used when VRF backend is not NETNS */
#define VRF_DEFAULT_NAME_INTERNAL "default"

DEFINE_MTYPE_STATIC(LIB, VRF, "VRF");
DEFINE_MTYPE_STATIC(LIB, VRF_BITMAP, "VRF bit-map");

DEFINE_QOBJ_TYPE(vrf);

static __inline int vrf_id_compare(const struct vrf *, const struct vrf *);
static __inline int vrf_name_compare(const struct vrf *, const struct vrf *);

RB_GENERATE(vrf_id_head, vrf, id_entry, vrf_id_compare);
RB_GENERATE(vrf_name_head, vrf, name_entry, vrf_name_compare);

struct vrf_id_head vrfs_by_id = RB_INITIALIZER(&vrfs_by_id);
struct vrf_name_head vrfs_by_name = RB_INITIALIZER(&vrfs_by_name);

static int vrf_backend;
static int vrf_backend_configured;
static char vrf_default_name[VRF_NAMSIZ] = VRF_DEFAULT_NAME_INTERNAL;

/*
 * Turn on/off debug code
 * for vrf.
 */
static int debug_vrf = 0;

/* Holding VRF hooks  */
static struct vrf_master {
        int (*vrf_new_hook)(struct vrf *);
        int (*vrf_delete_hook)(struct vrf *);
        int (*vrf_enable_hook)(struct vrf *);
        int (*vrf_disable_hook)(struct vrf *);
} vrf_master = {
        0,
};

static int vrf_is_enabled(struct vrf *vrf);

/* VRF list existance check by name. */
struct vrf *vrf_lookup_by_name(const char *name)
{
        struct vrf vrf;
        strlcpy(vrf.name, name, sizeof(vrf.name));
        return (RB_FIND(vrf_name_head, &vrfs_by_name, &vrf));
}

static __inline int vrf_id_compare(const struct vrf *a, const struct vrf *b)
{
        return (a->vrf_id - b->vrf_id);
}

static int vrf_name_compare(const struct vrf *a, const struct vrf *b)
{
        return strcmp(a->name, b->name);
}

int vrf_switch_to_netns(vrf_id_t vrf_id)
{
        char *name;
        struct vrf *vrf = vrf_lookup_by_id(vrf_id);

        /* VRF is default VRF. silently ignore */
        if (!vrf || vrf->vrf_id == VRF_DEFAULT)
                return 1;       /* 1 = default */
        /* VRF has no NETNS backend. silently ignore */
        if (vrf->data.l.netns_name[0] == '\0')
                return 2;       /* 2 = no netns */
        name = ns_netns_pathname(NULL, vrf->data.l.netns_name);
        if (debug_vrf)
                zlog_debug("VRF_SWITCH: %s(%u)", name, vrf->vrf_id);
        return ns_switch_to_netns(name);
}

int vrf_switchback_to_initial(void)
{
        int ret = ns_switchback_to_initial();

        if (ret == 0 && debug_vrf)
                zlog_debug("VRF_SWITCHBACK");
        return ret;
}

/* Get a VRF. If not found, create one.
 * Arg:
 *   name   - The name of the vrf.  May be NULL if unknown.
 *   vrf_id - The vrf_id of the vrf.  May be VRF_UNKNOWN if unknown
 * Description: Please note that this routine can be called with just the name
 * and 0 vrf-id
 */
struct vrf *vrf_get(vrf_id_t vrf_id, const char *name)
{
        struct vrf *vrf = NULL;
        int new = 0;

        /* Nothing to see, move along here */
        if (!name && vrf_id == VRF_UNKNOWN)
                return NULL;

        /* attempt to find already available VRF
         */
        if (name)
                vrf = vrf_lookup_by_name(name);
        if (vrf && vrf_id != VRF_UNKNOWN
            && vrf->vrf_id != VRF_UNKNOWN
            && vrf->vrf_id != vrf_id) {
                zlog_debug("VRF_GET: avoid %s creation(%u), same name exists (%u)",
                           name, vrf_id, vrf->vrf_id);
                return NULL;
        }
        /* Try to find VRF both by ID and name */
        if (!vrf && vrf_id != VRF_UNKNOWN)
                vrf = vrf_lookup_by_id(vrf_id);

        if (vrf == NULL) {
                vrf = XCALLOC(MTYPE_VRF, sizeof(struct vrf));
                vrf->vrf_id = VRF_UNKNOWN;
                QOBJ_REG(vrf, vrf);
                new = 1;

                if (debug_vrf)
                        zlog_debug("VRF(%u) %s is created.", vrf_id,
                                   (name) ? name : "(NULL)");
        }

        /* Set identifier */
        if (vrf_id != VRF_UNKNOWN && vrf->vrf_id == VRF_UNKNOWN) {
                vrf->vrf_id = vrf_id;
                RB_INSERT(vrf_id_head, &vrfs_by_id, vrf);
        }

        /* Set name */
        if (name && vrf->name[0] != '\0' && strcmp(name, vrf->name)) {
                /* update the vrf name */
                RB_REMOVE(vrf_name_head, &vrfs_by_name, vrf);
                strlcpy(vrf->data.l.netns_name,
                        name, NS_NAMSIZ);
                strlcpy(vrf->name, name, sizeof(vrf->name));
                RB_INSERT(vrf_name_head, &vrfs_by_name, vrf);
        } else if (name && vrf->name[0] == '\0') {
                strlcpy(vrf->name, name, sizeof(vrf->name));
                RB_INSERT(vrf_name_head, &vrfs_by_name, vrf);
        }
        if (new &&vrf_master.vrf_new_hook)
                (*vrf_master.vrf_new_hook)(vrf);

        return vrf;
}

/* Update a VRF. If not found, create one.
 * Arg:
 *   name   - The name of the vrf.
 *   vrf_id - The vrf_id of the vrf.
 * Description: This function first finds the vrf using its name. If the vrf is
 * found and the vrf-id of the existing vrf does not match the new vrf id, it
 * will disable the existing vrf and update it with new vrf-id. If the vrf is
 * not found, it will create the vrf with given name and the new vrf id.
 */
struct vrf *vrf_update(vrf_id_t new_vrf_id, const char *name)
{
        struct vrf *vrf = NULL;

        /*Treat VRF add for existing vrf as update
         * Update VRF ID and also update in VRF ID table
         */
        if (name)
                vrf = vrf_lookup_by_name(name);
        if (vrf && new_vrf_id != VRF_UNKNOWN && vrf->vrf_id != VRF_UNKNOWN
            && vrf->vrf_id != new_vrf_id) {
                if (debug_vrf) {
                        zlog_debug(
                                "Vrf Update event: %s old id: %u, new id: %u",
                                name, vrf->vrf_id, new_vrf_id);
                }

                /*Disable the vrf to simulate implicit delete
                 * so that all stale routes are deleted
                 * This vrf will be enabled down the line
                 */
                vrf_disable(vrf);


                RB_REMOVE(vrf_id_head, &vrfs_by_id, vrf);
                vrf->vrf_id = new_vrf_id;
                RB_INSERT(vrf_id_head, &vrfs_by_id, vrf);

        } else {

                /*
                 * vrf_get is implied creation if it does not exist
                 */
                vrf = vrf_get(new_vrf_id, name);
        }
        return vrf;
}

/* Delete a VRF. This is called when the underlying VRF goes away, a
 * pre-configured VRF is deleted or when shutting down (vrf_terminate()).
 */
void vrf_delete(struct vrf *vrf)
{
        if (debug_vrf)
                zlog_debug("VRF %s(%u) is to be deleted.", vrf->name,
                           vrf->vrf_id);

        if (vrf_is_enabled(vrf))
                vrf_disable(vrf);

        if (vrf->vrf_id != VRF_UNKNOWN) {
                RB_REMOVE(vrf_id_head, &vrfs_by_id, vrf);
                vrf->vrf_id = VRF_UNKNOWN;
        }

        /* If the VRF is user configured, it'll stick around, just remove
         * the ID mapping. Interfaces assigned to this VRF should've been
         * removed already as part of the VRF going down.
         */
        if (vrf_is_user_cfged(vrf))
                return;

        /* Do not delete the VRF if it has interfaces configured in it. */
        if (!RB_EMPTY(if_name_head, &vrf->ifaces_by_name))
                return;

        if (vrf_master.vrf_delete_hook)
                (*vrf_master.vrf_delete_hook)(vrf);

        QOBJ_UNREG(vrf);

        if (vrf->name[0] != '\0')
                RB_REMOVE(vrf_name_head, &vrfs_by_name, vrf);

        XFREE(MTYPE_VRF, vrf);
}

/* Look up a VRF by identifier. */
struct vrf *vrf_lookup_by_id(vrf_id_t vrf_id)
{
        struct vrf vrf;
        vrf.vrf_id = vrf_id;
        return (RB_FIND(vrf_id_head, &vrfs_by_id, &vrf));
}

/*
 * Enable a VRF - that is, let the VRF be ready to use.
 * The VRF_ENABLE_HOOK callback will be called to inform
 * that they can allocate resources in this VRF.
 *
 * RETURN: 1 - enabled successfully; otherwise, 0.
 */
int vrf_enable(struct vrf *vrf)
{
        if (vrf_is_enabled(vrf))
                return 1;

        if (debug_vrf)
                zlog_debug("VRF %s(%u) is enabled.", vrf->name, vrf->vrf_id);

        SET_FLAG(vrf->status, VRF_ACTIVE);

        if (vrf_master.vrf_enable_hook)
                (*vrf_master.vrf_enable_hook)(vrf);

        /*
         * If we have any nexthop group entries that
         * are awaiting vrf initialization then
         * let's let people know about it
         */
        nexthop_group_enable_vrf(vrf);

        return 1;
}

/*
 * Disable a VRF - that is, let the VRF be unusable.
 * The VRF_DELETE_HOOK callback will be called to inform
 * that they must release the resources in the VRF.
 */
void vrf_disable(struct vrf *vrf)
{
        if (!vrf_is_enabled(vrf))
                return;

        UNSET_FLAG(vrf->status, VRF_ACTIVE);

        if (debug_vrf)
                zlog_debug("VRF %s(%u) is to be disabled.", vrf->name,
                           vrf->vrf_id);

        /* Till now, nothing to be done for the default VRF. */
        // Pending: see why this statement.


        /*
         * When the vrf is disabled let's
         * handle all nexthop-groups associated
         * with this vrf
         */
        nexthop_group_disable_vrf(vrf);

        if (vrf_master.vrf_disable_hook)
                (*vrf_master.vrf_disable_hook)(vrf);
}

const char *vrf_id_to_name(vrf_id_t vrf_id)
{
        struct vrf *vrf;

        if (vrf_id == VRF_DEFAULT)
                return VRF_DEFAULT_NAME;

        vrf = vrf_lookup_by_id(vrf_id);
        return VRF_LOGNAME(vrf);
}

/* Look up the data pointer of the specified VRF. */
void *vrf_info_lookup(vrf_id_t vrf_id)
{
        struct vrf *vrf = vrf_lookup_by_id(vrf_id);
        return vrf ? vrf->info : NULL;
}

/*
 * VRF hash for storing set or not.
 */
struct vrf_bit_set {
        vrf_id_t vrf_id;
        bool set;
};

static unsigned int vrf_hash_bitmap_key(const void *data)
{
        const struct vrf_bit_set *bit = data;

        return bit->vrf_id;
}

static bool vrf_hash_bitmap_cmp(const void *a, const void *b)
{
        const struct vrf_bit_set *bit1 = a;
        const struct vrf_bit_set *bit2 = b;

        return bit1->vrf_id == bit2->vrf_id;
}

static void *vrf_hash_bitmap_alloc(void *data)
{
        struct vrf_bit_set *copy = data;
        struct vrf_bit_set *bit;

        bit = XMALLOC(MTYPE_VRF_BITMAP, sizeof(*bit));
        bit->vrf_id = copy->vrf_id;

        return bit;
}

static void vrf_hash_bitmap_free(void *data)
{
        struct vrf_bit_set *bit = data;

        XFREE(MTYPE_VRF_BITMAP, bit);
}

vrf_bitmap_t vrf_bitmap_init(void)
{
        return hash_create_size(32, vrf_hash_bitmap_key, vrf_hash_bitmap_cmp,
                                "VRF BIT HASH");
}

void vrf_bitmap_free(vrf_bitmap_t bmap)
{
        struct hash *vrf_hash = bmap;

        if (vrf_hash == NULL)
                return;

        hash_clean(vrf_hash, vrf_hash_bitmap_free);
        hash_free(vrf_hash);
}

void vrf_bitmap_set(vrf_bitmap_t bmap, vrf_id_t vrf_id)
{
        struct vrf_bit_set lookup = { .vrf_id = vrf_id };
        struct hash *vrf_hash = bmap;
        struct vrf_bit_set *bit;

        if (vrf_hash == NULL || vrf_id == VRF_UNKNOWN)
                return;

        bit = hash_get(vrf_hash, &lookup, vrf_hash_bitmap_alloc);
        bit->set = true;
}

void vrf_bitmap_unset(vrf_bitmap_t bmap, vrf_id_t vrf_id)
{
        struct vrf_bit_set lookup = { .vrf_id = vrf_id };
        struct hash *vrf_hash = bmap;
        struct vrf_bit_set *bit;

        if (vrf_hash == NULL || vrf_id == VRF_UNKNOWN)
                return;

        bit = hash_get(vrf_hash, &lookup, vrf_hash_bitmap_alloc);
        bit->set = false;
}

int vrf_bitmap_check(vrf_bitmap_t bmap, vrf_id_t vrf_id)
{
        struct vrf_bit_set lookup = { .vrf_id = vrf_id };
        struct hash *vrf_hash = bmap;
        struct vrf_bit_set *bit;

        if (vrf_hash == NULL || vrf_id == VRF_UNKNOWN)
                return 0;

        bit = hash_lookup(vrf_hash, &lookup);
        if (bit)
                return bit->set;

        return 0;
}

static void vrf_autocomplete(vector comps, struct cmd_token *token)
{
        struct vrf *vrf = NULL;

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

static const struct cmd_variable_handler vrf_var_handlers[] = {
        {
                .varname = "vrf",
                .completions = vrf_autocomplete,
        },
        {
                .varname = "vrf_name",
                .completions = vrf_autocomplete,
        },
        {
                .varname = "nexthop_vrf",
                .completions = vrf_autocomplete,
        },
        {.completions = NULL},
};

/* Initialize VRF module. */
void vrf_init(int (*create)(struct vrf *), int (*enable)(struct vrf *),
              int (*disable)(struct vrf *), int (*destroy)(struct vrf *))
{
        struct vrf *default_vrf;

        /* initialise NS, in case VRF backend if NETNS */
        ns_init();
        if (debug_vrf)
                zlog_debug("%s: Initializing VRF subsystem", __func__);

        vrf_master.vrf_new_hook = create;
        vrf_master.vrf_enable_hook = enable;
        vrf_master.vrf_disable_hook = disable;
        vrf_master.vrf_delete_hook = destroy;

        /* The default VRF always exists. */
        default_vrf = vrf_get(VRF_DEFAULT, VRF_DEFAULT_NAME);
        if (!default_vrf) {
                flog_err(EC_LIB_VRF_START,
                         "vrf_init: failed to create the default VRF!");
                exit(1);
        }
        if (vrf_is_backend_netns()) {
                struct ns *ns;

                strlcpy(default_vrf->data.l.netns_name,
                        VRF_DEFAULT_NAME, NS_NAMSIZ);
                ns = ns_lookup(NS_DEFAULT);
                ns->vrf_ctxt = default_vrf;
                default_vrf->ns_ctxt = ns;
        }

        /* Enable the default VRF. */
        if (!vrf_enable(default_vrf)) {
                flog_err(EC_LIB_VRF_START,
                         "vrf_init: failed to enable the default VRF!");
                exit(1);
        }

        cmd_variable_handler_register(vrf_var_handlers);
}

static void vrf_terminate_single(struct vrf *vrf)
{
        /* Clear configured flag and invoke delete. */
        UNSET_FLAG(vrf->status, VRF_CONFIGURED);
        if_terminate(vrf);
        vrf_delete(vrf);
}

/* Terminate VRF module. */
void vrf_terminate(void)
{
        struct vrf *vrf, *tmp;

        if (debug_vrf)
                zlog_debug("%s: Shutting down vrf subsystem", __func__);

        RB_FOREACH_SAFE (vrf, vrf_id_head, &vrfs_by_id, tmp) {
                if (vrf->vrf_id == VRF_DEFAULT)
                        continue;

                vrf_terminate_single(vrf);
        }

        RB_FOREACH_SAFE (vrf, vrf_name_head, &vrfs_by_name, tmp) {
                if (vrf->vrf_id == VRF_DEFAULT)
                        continue;

                vrf_terminate_single(vrf);
        }

        /* Finally terminate default VRF */
        vrf = vrf_lookup_by_id(VRF_DEFAULT);
        if (vrf)
                vrf_terminate_single(vrf);
}

int vrf_socket(int domain, int type, int protocol, vrf_id_t vrf_id,
               const char *interfacename)
{
        int ret, save_errno, ret2;

        ret = vrf_switch_to_netns(vrf_id);
        if (ret < 0)
                flog_err_sys(EC_LIB_SOCKET, "%s: Can't switch to VRF %u (%s)",
                             __func__, vrf_id, safe_strerror(errno));

        ret = socket(domain, type, protocol);
        save_errno = errno;
        ret2 = vrf_switchback_to_initial();
        if (ret2 < 0)
                flog_err_sys(EC_LIB_SOCKET,
                             "%s: Can't switchback from VRF %u (%s)", __func__,
                             vrf_id, safe_strerror(errno));
        errno = save_errno;
        if (ret <= 0)
                return ret;
        ret2 = vrf_bind(vrf_id, ret, interfacename);
        if (ret2 < 0) {
                close(ret);
                ret = ret2;
        }
        return ret;
}

int vrf_is_backend_netns(void)
{
        return (vrf_backend == VRF_BACKEND_NETNS);
}

int vrf_get_backend(void)
{
        if (!vrf_backend_configured)
                return VRF_BACKEND_UNKNOWN;
        return vrf_backend;
}

int vrf_configure_backend(enum vrf_backend_type backend)
{
        /* Work around issue in old gcc */
        switch (backend) {
        case VRF_BACKEND_UNKNOWN:
        case VRF_BACKEND_NETNS:
        case VRF_BACKEND_VRF_LITE:
                break;
        default:
                return -1;
        }

        vrf_backend = backend;
        vrf_backend_configured = 1;

        return 0;
}

/* vrf CLI commands */
DEFUN_NOSH(vrf_exit,
           vrf_exit_cmd,
           "exit-vrf",
           "Exit current mode and down to previous mode\n")
{
        cmd_exit(vty);
        return CMD_SUCCESS;
}

DEFUN_YANG_NOSH (vrf,
       vrf_cmd,
       "vrf NAME",
       "Select a VRF to configure\n"
       "VRF's name\n")
{
        int idx_name = 1;
        const char *vrfname = argv[idx_name]->arg;
        char xpath_list[XPATH_MAXLEN];
        struct vrf *vrf;
        int ret;

        if (strlen(vrfname) > VRF_NAMSIZ) {
                vty_out(vty,
                        "%% VRF name %s invalid: length exceeds %d bytes\n",
                        vrfname, VRF_NAMSIZ);
                return CMD_WARNING_CONFIG_FAILED;
        }

        snprintf(xpath_list, sizeof(xpath_list), FRR_VRF_KEY_XPATH, vrfname);

        nb_cli_enqueue_change(vty, xpath_list, NB_OP_CREATE, NULL);
        ret = nb_cli_apply_changes_clear_pending(vty, xpath_list);
        if (ret == CMD_SUCCESS) {
                VTY_PUSH_XPATH(VRF_NODE, xpath_list);
                vrf = vrf_lookup_by_name(vrfname);
                if (vrf)
                        VTY_PUSH_CONTEXT(VRF_NODE, vrf);
        }

        return ret;
}

DEFUN_YANG (no_vrf,
       no_vrf_cmd,
       "no vrf NAME",
       NO_STR
       "Delete a pseudo VRF's configuration\n"
       "VRF's name\n")
{
        const char *vrfname = argv[2]->arg;
        char xpath_list[XPATH_MAXLEN];

        struct vrf *vrfp;

        vrfp = vrf_lookup_by_name(vrfname);

        if (vrfp == NULL)
                return CMD_SUCCESS;

        if (CHECK_FLAG(vrfp->status, VRF_ACTIVE)) {
                vty_out(vty, "%% Only inactive VRFs can be deleted\n");
                return CMD_WARNING_CONFIG_FAILED;
        }

        if (vrf_get_backend() == VRF_BACKEND_VRF_LITE) {
                /*
                 * Remove the VRF interface config when removing the VRF.
                 */
                snprintf(xpath_list, sizeof(xpath_list),
                         "/frr-interface:lib/interface[name='%s']", vrfname);
                nb_cli_enqueue_change(vty, xpath_list, NB_OP_DESTROY, NULL);
        }

        snprintf(xpath_list, sizeof(xpath_list), FRR_VRF_KEY_XPATH, vrfname);

        nb_cli_enqueue_change(vty, xpath_list, NB_OP_DESTROY, NULL);
        return nb_cli_apply_changes(vty, NULL);
}


static struct cmd_node vrf_node = {
        .name = "vrf",
        .node = VRF_NODE,
        .parent_node = CONFIG_NODE,
        .prompt = "%s(config-vrf)# ",
};

/*
 * Debug CLI for vrf's
 */
DEFUN (vrf_debug,
      vrf_debug_cmd,
      "debug vrf",
      DEBUG_STR
      "VRF Debugging\n")
{
        debug_vrf = 1;

        return CMD_SUCCESS;
}

DEFUN (no_vrf_debug,
      no_vrf_debug_cmd,
      "no debug vrf",
      NO_STR
      DEBUG_STR
      "VRF Debugging\n")
{
        debug_vrf = 0;

        return CMD_SUCCESS;
}

static int vrf_write_host(struct vty *vty)
{
        if (debug_vrf)
                vty_out(vty, "debug vrf\n");

        return 1;
}

static int vrf_write_host(struct vty *vty);
static struct cmd_node vrf_debug_node = {
        .name = "vrf debug",
        .node = VRF_DEBUG_NODE,
        .prompt = "",
        .config_write = vrf_write_host,
};

void vrf_install_commands(void)
{
        install_node(&vrf_debug_node);

        install_element(CONFIG_NODE, &vrf_debug_cmd);
        install_element(ENABLE_NODE, &vrf_debug_cmd);
        install_element(CONFIG_NODE, &no_vrf_debug_cmd);
        install_element(ENABLE_NODE, &no_vrf_debug_cmd);
}

void vrf_cmd_init(int (*writefunc)(struct vty *vty))
{
        install_element(CONFIG_NODE, &vrf_cmd);
        install_element(CONFIG_NODE, &no_vrf_cmd);
        vrf_node.config_write = writefunc;
        install_node(&vrf_node);
        install_default(VRF_NODE);
        install_element(VRF_NODE, &vrf_exit_cmd);
}

void vrf_set_default_name(const char *default_name)
{
        snprintf(vrf_default_name, VRF_NAMSIZ, "%s", default_name);
}

const char *vrf_get_default_name(void)
{
        return vrf_default_name;
}

int vrf_bind(vrf_id_t vrf_id, int fd, const char *ifname)
{
        int ret = 0;
        struct interface *ifp;
        struct vrf *vrf;

        if (fd < 0)
                return -1;

        if (vrf_id == VRF_UNKNOWN)
                return -1;

        /* can't bind to a VRF that doesn't exist */
        vrf = vrf_lookup_by_id(vrf_id);
        if (!vrf_is_enabled(vrf))
                return -1;

        if (ifname && strcmp(ifname, vrf->name)) {
                /* binding to a regular interface */

                /* can't bind to an interface that doesn't exist */
                ifp = if_lookup_by_name(ifname, vrf_id);
                if (!ifp)
                        return -1;
        } else {
                /* binding to a VRF device */

                /* nothing to do for netns */
                if (vrf_is_backend_netns())
                        return 0;

                /* nothing to do for default vrf */
                if (vrf_id == VRF_DEFAULT)
                        return 0;

                ifname = vrf->name;
        }

#ifdef SO_BINDTODEVICE
        ret = setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, ifname,
                         strlen(ifname) + 1);
        if (ret < 0)
                zlog_err("bind to interface %s failed, errno=%d", ifname,
                         errno);
#endif /* SO_BINDTODEVICE */
        return ret;
}
int vrf_getaddrinfo(const char *node, const char *service,
                    const struct addrinfo *hints, struct addrinfo **res,
                    vrf_id_t vrf_id)
{
        int ret, ret2, save_errno;

        ret = vrf_switch_to_netns(vrf_id);
        if (ret < 0)
                flog_err_sys(EC_LIB_SOCKET, "%s: Can't switch to VRF %u (%s)",
                             __func__, vrf_id, safe_strerror(errno));
        ret = getaddrinfo(node, service, hints, res);
        save_errno = errno;
        ret2 = vrf_switchback_to_initial();
        if (ret2 < 0)
                flog_err_sys(EC_LIB_SOCKET,
                             "%s: Can't switchback from VRF %u (%s)", __func__,
                             vrf_id, safe_strerror(errno));
        errno = save_errno;
        return ret;
}

int vrf_ioctl(vrf_id_t vrf_id, int d, unsigned long request, char *params)
{
        int ret, saved_errno, rc;

        ret = vrf_switch_to_netns(vrf_id);
        if (ret < 0) {
                flog_err_sys(EC_LIB_SOCKET, "%s: Can't switch to VRF %u (%s)",
                             __func__, vrf_id, safe_strerror(errno));
                return 0;
        }
        rc = ioctl(d, request, params);
        saved_errno = errno;
        ret = vrf_switchback_to_initial();
        if (ret < 0)
                flog_err_sys(EC_LIB_SOCKET,
                             "%s: Can't switchback from VRF %u (%s)", __func__,
                             vrf_id, safe_strerror(errno));
        errno = saved_errno;
        return rc;
}

int vrf_sockunion_socket(const union sockunion *su, vrf_id_t vrf_id,
                         const char *interfacename)
{
        int ret, save_errno, ret2;

        ret = vrf_switch_to_netns(vrf_id);
        if (ret < 0)
                flog_err_sys(EC_LIB_SOCKET, "%s: Can't switch to VRF %u (%s)",
                             __func__, vrf_id, safe_strerror(errno));
        ret = sockunion_socket(su);
        save_errno = errno;
        ret2 = vrf_switchback_to_initial();
        if (ret2 < 0)
                flog_err_sys(EC_LIB_SOCKET,
                             "%s: Can't switchback from VRF %u (%s)", __func__,
                             vrf_id, safe_strerror(errno));
        errno = save_errno;

        if (ret <= 0)
                return ret;
        ret2 = vrf_bind(vrf_id, ret, interfacename);
        if (ret2 < 0) {
                close(ret);
                ret = ret2;
        }
        return ret;
}

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

/*
 * XPath: /frr-vrf:lib/vrf
 */
static int lib_vrf_create(struct nb_cb_create_args *args)
{
        const char *vrfname;
        struct vrf *vrfp;

        vrfname = yang_dnode_get_string(args->dnode, "./name");

        if (args->event != NB_EV_APPLY)
                return NB_OK;

        vrfp = vrf_get(VRF_UNKNOWN, vrfname);

        SET_FLAG(vrfp->status, VRF_CONFIGURED);
        nb_running_set_entry(args->dnode, vrfp);

        return NB_OK;
}

static int lib_vrf_destroy(struct nb_cb_destroy_args *args)
{
        struct vrf *vrfp;

        switch (args->event) {
        case NB_EV_VALIDATE:
                vrfp = nb_running_get_entry(args->dnode, NULL, true);
                if (CHECK_FLAG(vrfp->status, VRF_ACTIVE)) {
                        snprintf(args->errmsg, args->errmsg_len,
                                 "Only inactive VRFs can be deleted");
                        return NB_ERR_VALIDATION;
                }
                break;
        case NB_EV_PREPARE:
        case NB_EV_ABORT:
                break;
        case NB_EV_APPLY:
                vrfp = nb_running_unset_entry(args->dnode);

                /* Clear configured flag and invoke delete. */
                UNSET_FLAG(vrfp->status, VRF_CONFIGURED);
                vrf_delete(vrfp);
                break;
        }

        return NB_OK;
}

static const void *lib_vrf_get_next(struct nb_cb_get_next_args *args)
{
        struct vrf *vrfp = (struct vrf *)args->list_entry;

        if (args->list_entry == NULL) {
                vrfp = RB_MIN(vrf_name_head, &vrfs_by_name);
        } else {
                vrfp = RB_NEXT(vrf_name_head, vrfp);
        }

        return vrfp;
}

static int lib_vrf_get_keys(struct nb_cb_get_keys_args *args)
{
        struct vrf *vrfp = (struct vrf *)args->list_entry;

        args->keys->num = 1;
        strlcpy(args->keys->key[0], vrfp->name, sizeof(args->keys->key[0]));

        return NB_OK;
}

static const void *lib_vrf_lookup_entry(struct nb_cb_lookup_entry_args *args)
{
        const char *vrfname = args->keys->key[0];

        struct vrf *vrf = vrf_lookup_by_name(vrfname);

        return vrf;
}

/*
 * XPath: /frr-vrf:lib/vrf/id
 */
static struct yang_data *
lib_vrf_state_id_get_elem(struct nb_cb_get_elem_args *args)
{
        struct vrf *vrfp = (struct vrf *)args->list_entry;

        return yang_data_new_uint32(args->xpath, vrfp->vrf_id);
}

/*
 * XPath: /frr-vrf:lib/vrf/active
 */
static struct yang_data *
lib_vrf_state_active_get_elem(struct nb_cb_get_elem_args *args)
{
        struct vrf *vrfp = (struct vrf *)args->list_entry;

        if (vrfp->status == VRF_ACTIVE)
                return yang_data_new_bool(
                        args->xpath, vrfp->status == VRF_ACTIVE ? true : false);

        return NULL;
}

/* clang-format off */
const struct frr_yang_module_info frr_vrf_info = {
        .name = "frr-vrf",
        .nodes = {
                {
                        .xpath = "/frr-vrf:lib/vrf",
                        .cbs = {
                                .create = lib_vrf_create,
                                .destroy = lib_vrf_destroy,
                                .get_next = lib_vrf_get_next,
                                .get_keys = lib_vrf_get_keys,
                                .lookup_entry = lib_vrf_lookup_entry,
                        },
                        .priority = NB_DFLT_PRIORITY - 2,
                },
                {
                        .xpath = "/frr-vrf:lib/vrf/state/id",
                        .cbs = {
                                .get_elem = lib_vrf_state_id_get_elem,
                        }
                },
                {
                        .xpath = "/frr-vrf:lib/vrf/state/active",
                        .cbs = {
                                .get_elem = lib_vrf_state_active_get_elem,
                        }
                },
                {
                        .xpath = NULL,
                },
        }
};