path: root/babeld/babel_interface.c

// SPDX-License-Identifier: MIT
/*
Copyright 2011 by Matthieu Boutier and Juliusz Chroboczek
*/

#include <zebra.h>
#include "memory.h"
#include "log.h"
#include "command.h"
#include "prefix.h"
#include "vector.h"
#include "distribute.h"
#include "lib_errors.h"
#include "network.h"

#include "babel_main.h"
#include "util.h"
#include "kernel.h"
#include "babel_interface.h"
#include "message.h"
#include "route.h"
#include "babel_zebra.h"
#include "neighbour.h"
#include "route.h"
#include "xroute.h"
#include "babel_errors.h"

#ifndef VTYSH_EXTRACT_PL
#include "babeld/babel_interface_clippy.c"
#endif

DEFINE_MTYPE_STATIC(BABELD, BABEL_IF, "Babel Interface");

#define IS_ENABLE(ifp) (babel_enable_if_lookup(ifp->name) >= 0)

static int babel_enable_if_lookup (const char *ifname);
static int babel_enable_if_add (const char *ifname);
static int babel_enable_if_delete (const char *ifname);
static int interface_recalculate(struct interface *ifp);
static int interface_reset(struct interface *ifp);
static int babel_if_new_hook    (struct interface *ifp);
static int babel_if_delete_hook (struct interface *ifp);
static int interface_config_write (struct vty *vty);
static babel_interface_nfo * babel_interface_allocate (void);
static void babel_interface_free (babel_interface_nfo *bi);


static vector babel_enable_if;                 /* enable interfaces (by cmd). */

int babel_ifp_up(struct interface *ifp)
{
    debugf(BABEL_DEBUG_IF, "receive a 'interface up'");

    interface_recalculate(ifp);
    return 0;
}

int
babel_ifp_down(struct interface *ifp)
{
    debugf(BABEL_DEBUG_IF, "receive a 'interface down'");

    if (ifp == NULL) {
        return 0;
    }

    interface_reset(ifp);
    return 0;
}

int babel_ifp_create (struct interface *ifp)
{
    debugf(BABEL_DEBUG_IF, "receive a 'interface add'");

    interface_recalculate(ifp);

     return 0;
 }

int
babel_ifp_destroy(struct interface *ifp)
{
    debugf(BABEL_DEBUG_IF, "receive a 'interface delete'");

    if (IS_ENABLE(ifp))
        interface_reset(ifp);

    return 0;
}

int
babel_interface_address_add (ZAPI_CALLBACK_ARGS)
{
    babel_interface_nfo *babel_ifp;
    struct connected *ifc;
    struct prefix *prefix;

    debugf(BABEL_DEBUG_IF, "receive a 'interface address add'");

    ifc = zebra_interface_address_read (ZEBRA_INTERFACE_ADDRESS_ADD,
                                        zclient->ibuf, vrf_id);

    if (ifc == NULL)
        return 0;

    prefix = ifc->address;

    if (prefix->family == AF_INET) {
        flush_interface_routes(ifc->ifp, 0);
        babel_ifp = babel_get_if_nfo(ifc->ifp);
        if (babel_ifp->ipv4 == NULL) {
            babel_ifp->ipv4 = malloc(4);
            if (babel_ifp->ipv4 == NULL) {
                flog_err(EC_BABEL_MEMORY, "not enough memory");
            } else {
                memcpy(babel_ifp->ipv4, &prefix->u.prefix4, 4);
            }
        }
    }

    send_request(ifc->ifp, NULL, 0);
    send_update(ifc->ifp, 0, NULL, 0);

    return 0;
}

int
babel_interface_address_delete (ZAPI_CALLBACK_ARGS)
{
    babel_interface_nfo *babel_ifp;
    struct connected *ifc;
    struct prefix *prefix;

    debugf(BABEL_DEBUG_IF, "receive a 'interface address delete'");

    ifc = zebra_interface_address_read (ZEBRA_INTERFACE_ADDRESS_DELETE,
                                        zclient->ibuf, vrf_id);

    if (ifc == NULL)
        return 0;

    prefix = ifc->address;

    if (prefix->family == AF_INET) {
        flush_interface_routes(ifc->ifp, 0);
        babel_ifp = babel_get_if_nfo(ifc->ifp);
	if (babel_ifp->ipv4 != NULL
	    && memcmp(babel_ifp->ipv4, &prefix->u.prefix4, IPV4_MAX_BYTELEN)
		       == 0) {
		free(babel_ifp->ipv4);
		babel_ifp->ipv4 = NULL;
        }
    }

    send_request(ifc->ifp, NULL, 0);
    send_update(ifc->ifp, 0, NULL, 0);

    connected_free(&ifc);
    return 0;
}

/* Lookup function. */
static int
babel_enable_if_lookup (const char *ifname)
{
    unsigned int i;
    char *str;

    for (i = 0; i < vector_active (babel_enable_if); i++)
        if ((str = vector_slot (babel_enable_if, i)) != NULL)
            if (strcmp (str, ifname) == 0)
                return i;
    return -1;
}

/* Add interface to babel_enable_if. */
static int
babel_enable_if_add (const char *ifname)
{
    int ret;
    struct interface *ifp = NULL;

    ret = babel_enable_if_lookup (ifname);
    if (ret >= 0)
        return -1;

    vector_set (babel_enable_if, strdup (ifname));

    ifp = if_lookup_by_name(ifname, VRF_DEFAULT);
    if (ifp != NULL)
        interface_recalculate(ifp);

    return 1;
}

/* Delete interface from babel_enable_if. */
static int
babel_enable_if_delete (const char *ifname)
{
    int babel_enable_if_index;
    char *str;
    struct interface *ifp = NULL;

    babel_enable_if_index = babel_enable_if_lookup (ifname);
    if (babel_enable_if_index < 0)
        return -1;

    str = vector_slot (babel_enable_if, babel_enable_if_index);
    free (str);
    vector_unset (babel_enable_if, babel_enable_if_index);

    ifp = if_lookup_by_name(ifname, VRF_DEFAULT);
    if (ifp != NULL)
        interface_reset(ifp);

    return 1;
}

/* [Babel Command] Babel enable on specified interface or matched network. */
DEFUN (babel_network,
       babel_network_cmd,
       "network IF_OR_ADDR",
       "Enable Babel protocol on specified interface or network.\n"
       "Interface or address\n")
{
    int ret;
    struct prefix p;

    ret = str2prefix (argv[1]->arg, &p);

    /* Given string is:               */
    if (ret) /* an IPv4 or v6 network */
        return CMD_ERR_NO_MATCH; /* not implemented yet */
    else     /* an interface name     */
        ret = babel_enable_if_add (argv[1]->arg);

    if (ret < 0) {
        vty_out (vty, "There is same network configuration %s\n",
                   argv[1]->arg);
        return CMD_WARNING;
    }

    return CMD_SUCCESS;
}

/* [Babel Command] Babel enable on specified interface or matched network. */
DEFUN (no_babel_network,
       no_babel_network_cmd,
       "no network IF_OR_ADDR",
       NO_STR
       "Disable Babel protocol on specified interface or network.\n"
       "Interface or address\n")
{
    int ret;
    struct prefix p;

    ret = str2prefix (argv[2]->arg, &p);

    /* Given string is:               */
    if (ret) /* an IPv4 or v6 network */
        return CMD_ERR_NO_MATCH; /* not implemented yet */
    else     /* an interface name     */
        ret = babel_enable_if_delete (argv[2]->arg);

    if (ret < 0) {
        vty_out (vty, "can't find network %s\n",argv[2]->arg);
        return CMD_WARNING_CONFIG_FAILED;
    }

    return CMD_SUCCESS;
}

/* There are a number of interface parameters that must be changed when
   an interface becomes wired/wireless.  In Quagga, they cannot be
   configured separately. */

static void
babel_set_wired_internal(babel_interface_nfo *babel_ifp, int wired)
{
    if(wired) {
        babel_ifp->flags |= BABEL_IF_WIRED;
        babel_ifp->flags |= BABEL_IF_SPLIT_HORIZON;
        babel_ifp->cost = BABEL_DEFAULT_RXCOST_WIRED;
        babel_ifp->channel = BABEL_IF_CHANNEL_NONINTERFERING;
        babel_ifp->flags &= ~BABEL_IF_LQ;
    } else {
        babel_ifp->flags &= ~BABEL_IF_WIRED;
        babel_ifp->flags &= ~BABEL_IF_SPLIT_HORIZON;
        babel_ifp->cost = BABEL_DEFAULT_RXCOST_WIRELESS;
        babel_ifp->channel = BABEL_IF_CHANNEL_INTERFERING;
        babel_ifp->flags |= BABEL_IF_LQ;
    }

}

/* [Interface Command] Tell the interface is wire. */
DEFPY (babel_set_wired,
       babel_set_wired_cmd,
       "[no] babel wired",
       NO_STR
       "Babel interface commands\n"
       "Enable wired optimizations\n")
{
    VTY_DECLVAR_CONTEXT(interface, ifp);
    babel_interface_nfo *babel_ifp;

    babel_ifp = babel_get_if_nfo(ifp);

    assert (babel_ifp != NULL);
    babel_set_wired_internal(babel_ifp, no ? 0 : 1);
    return CMD_SUCCESS;
}

/* [Interface Command] Tell the interface is wireless (default). */
DEFPY (babel_set_wireless,
       babel_set_wireless_cmd,
       "[no] babel wireless",
       NO_STR
       "Babel interface commands\n"
       "Disable wired optimizations (assume wireless)\n")
{
    VTY_DECLVAR_CONTEXT(interface, ifp);
    babel_interface_nfo *babel_ifp;

    babel_ifp = babel_get_if_nfo(ifp);

    assert (babel_ifp != NULL);
    babel_set_wired_internal(babel_ifp, no ? 1 : 0);
    return CMD_SUCCESS;
}

/* [Interface Command] Enable split horizon. */
DEFPY (babel_split_horizon,
       babel_split_horizon_cmd,
       "[no] babel split-horizon",
       NO_STR
       "Babel interface commands\n"
       "Enable split horizon processing\n")
{
    VTY_DECLVAR_CONTEXT(interface, ifp);
    babel_interface_nfo *babel_ifp;

    babel_ifp = babel_get_if_nfo(ifp);

    assert (babel_ifp != NULL);
    if (!no)
        SET_FLAG(babel_ifp->flags, BABEL_IF_SPLIT_HORIZON);
    else
        UNSET_FLAG(babel_ifp->flags, BABEL_IF_SPLIT_HORIZON);
    return CMD_SUCCESS;
}

/* [Interface Command]. */
DEFPY (babel_set_hello_interval,
       babel_set_hello_interval_cmd,
       "[no] babel hello-interval (20-655340)",
       NO_STR
       "Babel interface commands\n"
       "Time between scheduled hellos\n"
       "Milliseconds\n")
{
    VTY_DECLVAR_CONTEXT(interface, ifp);
    babel_interface_nfo *babel_ifp;

    babel_ifp = babel_get_if_nfo(ifp);
    assert (babel_ifp != NULL);

    babel_ifp->hello_interval = no ?
        BABEL_DEFAULT_HELLO_INTERVAL : hello_interval;
    return CMD_SUCCESS;
}

/* [Interface Command]. */
DEFPY (babel_set_update_interval,
       babel_set_update_interval_cmd,
       "[no] babel update-interval (20-655340)",
       NO_STR
       "Babel interface commands\n"
       "Time between scheduled updates\n"
       "Milliseconds\n")
{
    VTY_DECLVAR_CONTEXT(interface, ifp);
    babel_interface_nfo *babel_ifp;

    babel_ifp = babel_get_if_nfo(ifp);
    assert (babel_ifp != NULL);

    babel_ifp->update_interval = no ?
        BABEL_DEFAULT_UPDATE_INTERVAL : update_interval;
    return CMD_SUCCESS;
}

DEFPY (babel_set_rxcost,
       babel_set_rxcost_cmd,
       "[no] babel rxcost (1-65534)",
       NO_STR
       "Babel interface commands\n"
       "Rxcost multiplier\n"
       "Units\n")
{
    VTY_DECLVAR_CONTEXT(interface, ifp);
    babel_interface_nfo *babel_ifp;

    babel_ifp = babel_get_if_nfo(ifp);
    assert (babel_ifp != NULL);

    if (no)
        rxcost = CHECK_FLAG(babel_ifp->flags, BABEL_IF_WIRED) ?
            BABEL_DEFAULT_RXCOST_WIRED : BABEL_DEFAULT_RXCOST_WIRELESS;

    babel_ifp->cost = rxcost;
    return CMD_SUCCESS;
}

DEFPY (babel_set_rtt_decay,
       babel_set_rtt_decay_cmd,
       "[no] babel rtt-decay (1-256)",
       NO_STR
       "Babel interface commands\n"
       "Decay factor for exponential moving average of RTT samples\n"
       "Units of 1/256\n")
{
    VTY_DECLVAR_CONTEXT(interface, ifp);
    babel_interface_nfo *babel_ifp;

    babel_ifp = babel_get_if_nfo(ifp);
    assert (babel_ifp != NULL);

    babel_ifp->rtt_decay = no ? BABEL_DEFAULT_RTT_DECAY : rtt_decay;
    return CMD_SUCCESS;
}

DEFPY (babel_set_rtt_min,
       babel_set_rtt_min_cmd,
       "[no] babel rtt-min (1-65535)",
       NO_STR
       "Babel interface commands\n"
       "Minimum RTT starting for increasing cost\n"
       "Milliseconds\n")
{
    VTY_DECLVAR_CONTEXT(interface, ifp);
    babel_interface_nfo *babel_ifp;

    babel_ifp = babel_get_if_nfo(ifp);
    assert (babel_ifp != NULL);

    /* The value is entered in milliseconds but stored as microseconds. */
    babel_ifp->rtt_min = no ? BABEL_DEFAULT_RTT_MIN : rtt_min * 1000;
    return CMD_SUCCESS;
}

DEFPY (babel_set_rtt_max,
       babel_set_rtt_max_cmd,
       "[no] babel rtt-max (1-65535)",
       NO_STR
       "Babel interface commands\n"
       "Maximum RTT\n"
       "Milliseconds\n")
{
    VTY_DECLVAR_CONTEXT(interface, ifp);
    babel_interface_nfo *babel_ifp;

    babel_ifp = babel_get_if_nfo(ifp);
    assert (babel_ifp != NULL);

    /* The value is entered in milliseconds but stored as microseconds. */
    babel_ifp->rtt_max = no ? BABEL_DEFAULT_RTT_MAX : rtt_max * 1000;
    return CMD_SUCCESS;
}

DEFPY (babel_set_max_rtt_penalty,
       babel_set_max_rtt_penalty_cmd,
       "[no] babel max-rtt-penalty (0-65535)",
       NO_STR
       "Babel interface commands\n"
       "Maximum additional cost due to RTT\n"
       "Milliseconds\n")
{
  VTY_DECLVAR_CONTEXT(interface, ifp);
    babel_interface_nfo *babel_ifp;

    babel_ifp = babel_get_if_nfo(ifp);
    assert (babel_ifp != NULL);

    babel_ifp->max_rtt_penalty = no ?
        BABEL_DEFAULT_MAX_RTT_PENALTY : max_rtt_penalty;
    return CMD_SUCCESS;
}

DEFPY (babel_set_enable_timestamps,
       babel_set_enable_timestamps_cmd,
       "[no] babel enable-timestamps",
       NO_STR
       "Babel interface commands\n"
       "Enable timestamps\n")
{
    VTY_DECLVAR_CONTEXT(interface, ifp);
    babel_interface_nfo *babel_ifp;

    babel_ifp = babel_get_if_nfo(ifp);
    assert (babel_ifp != NULL);
    if (!no)
        SET_FLAG(babel_ifp->flags, BABEL_IF_TIMESTAMPS);
    else
        UNSET_FLAG(babel_ifp->flags, BABEL_IF_TIMESTAMPS);
    return CMD_SUCCESS;
}

DEFPY (babel_set_channel,
       babel_set_channel_cmd,
       "[no] babel channel <(1-254)$ch|interfering$interfering|"
       "noninterfering$noninterfering>",
       NO_STR
       "Babel interface commands\n"
       "Channel number for diversity routing\n"
       "Number\n"
       "Mark channel as interfering\n"
       "Mark channel as noninterfering\n"
       )
{
    VTY_DECLVAR_CONTEXT(interface, ifp);
    babel_interface_nfo *babel_ifp;

    babel_ifp = babel_get_if_nfo(ifp);
    assert (babel_ifp != NULL);

    if (no)
        ch = CHECK_FLAG(babel_ifp->flags, BABEL_IF_WIRED) ?
            BABEL_IF_CHANNEL_NONINTERFERING : BABEL_IF_CHANNEL_INTERFERING;
    else if (interfering)
        ch = BABEL_IF_CHANNEL_INTERFERING;
    else if (noninterfering)
        ch = BABEL_IF_CHANNEL_NONINTERFERING;

    babel_ifp->channel = ch;
    return CMD_SUCCESS;
}

/* This should be no more than half the hello interval, so that hellos
   aren't sent late.  The result is in milliseconds. */
unsigned
jitter(babel_interface_nfo *babel_ifp, int urgent)
{
    unsigned interval = babel_ifp->hello_interval;
    if(urgent)
        interval = MIN(interval, 100);
    else
        interval = MIN(interval, 4000);
    return roughly(interval) / 4;
}

unsigned
update_jitter(babel_interface_nfo *babel_ifp, int urgent)
{
    unsigned interval = babel_ifp->hello_interval;
    if(urgent)
        interval = MIN(interval, 100);
    else
        interval = MIN(interval, 4000);
    return roughly(interval);
}

/* calculate babeld's specific datas of an interface (change when the interface
 change) */
static int
interface_recalculate(struct interface *ifp)
{
    babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
    unsigned char *tmp = NULL;
    int mtu, rc;
    struct ipv6_mreq mreq;

    if (!IS_ENABLE(ifp))
        return -1;

    if (!if_is_operative(ifp) || !CHECK_FLAG(ifp->flags, IFF_RUNNING)) {
        interface_reset(ifp);
        return -1;
    }

    babel_ifp->flags |= BABEL_IF_IS_UP;

    mtu = MIN(ifp->mtu, ifp->mtu6);

    /* We need to be able to fit at least two messages into a packet,
     so MTUs below 116 require lower layer fragmentation. */
    /* In IPv6, the minimum MTU is 1280, and every host must be able
     to reassemble up to 1500 bytes, but I'd rather not rely on this. */
    if(mtu < 128) {
        debugf(BABEL_DEBUG_IF, "Suspiciously low MTU %d on interface %s (%d).",
               mtu, ifp->name, ifp->ifindex);
        mtu = 128;
    }

    /* 4 for Babel header; 40 for IPv6 header, 8 for UDP header, 12 for good luck. */
    babel_ifp->bufsize = mtu - 4 - 60;
    tmp = babel_ifp->sendbuf;
    babel_ifp->sendbuf = realloc(babel_ifp->sendbuf, babel_ifp->bufsize);
    if(babel_ifp->sendbuf == NULL) {
        flog_err(EC_BABEL_MEMORY, "Couldn't reallocate sendbuf.");
        free(tmp);
        babel_ifp->bufsize = 0;
        return -1;
    }
    tmp = NULL;

    rc = resize_receive_buffer(mtu);
    if(rc < 0)
        zlog_warn("couldn't resize receive buffer for interface %s (%d) (%d bytes).",
                  ifp->name, ifp->ifindex, mtu);

    memset(&mreq, 0, sizeof(mreq));
    memcpy(&mreq.ipv6mr_multiaddr, protocol_group, 16);
    mreq.ipv6mr_interface = ifp->ifindex;

    rc = setsockopt(protocol_socket, IPPROTO_IPV6, IPV6_JOIN_GROUP,
                    (char*)&mreq, sizeof(mreq));
    if (rc < 0 && errno != EADDRINUSE) {
	    flog_err_sys(EC_LIB_SOCKET,
			 "setsockopt(IPV6_JOIN_GROUP) on interface '%s': %s",
			 ifp->name, safe_strerror(errno));
	    /* This is probably due to a missing link-local address,
	     so down this interface, and wait until the main loop
	     tries to up it again. */
	    interface_reset(ifp);
	    return -1;
    }

    set_timeout(&babel_ifp->hello_timeout, babel_ifp->hello_interval);
    set_timeout(&babel_ifp->update_timeout, babel_ifp->update_interval);
    send_hello(ifp);
    send_request(ifp, NULL, 0);

    update_interface_metric(ifp);

    debugf(BABEL_DEBUG_COMMON,
           "Upped interface %s (%s, cost=%d, channel=%d%s).",
           ifp->name,
           (babel_ifp->flags & BABEL_IF_WIRED) ? "wired" : "wireless",
           babel_ifp->cost,
           babel_ifp->channel,
           babel_ifp->ipv4 ? ", IPv4" : "");

    if(rc > 0)
        send_update(ifp, 0, NULL, 0);

    return 1;
}

/* Reset the interface as it was new: it's not removed from the interface list,
 and may be considered as a upped interface. */
static int
interface_reset(struct interface *ifp)
{
    int rc;
    struct ipv6_mreq mreq;
    babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);

    if (!(babel_ifp->flags & BABEL_IF_IS_UP))
        return 0;

    debugf(BABEL_DEBUG_IF, "interface reset: %s", ifp->name);
    babel_ifp->flags &= ~BABEL_IF_IS_UP;

    flush_interface_routes(ifp, 0);
    babel_ifp->buffered = 0;
    babel_ifp->bufsize = 0;
    free(babel_ifp->sendbuf);
    babel_ifp->num_buffered_updates = 0;
    babel_ifp->update_bufsize = 0;
    if(babel_ifp->buffered_updates)
        free(babel_ifp->buffered_updates);
    babel_ifp->buffered_updates = NULL;
    babel_ifp->sendbuf = NULL;

    if(ifp->ifindex > 0) {
        memset(&mreq, 0, sizeof(mreq));
        memcpy(&mreq.ipv6mr_multiaddr, protocol_group, 16);
        mreq.ipv6mr_interface = ifp->ifindex;
        rc = setsockopt(protocol_socket, IPPROTO_IPV6, IPV6_LEAVE_GROUP,
                        (char*)&mreq, sizeof(mreq));
        if(rc < 0)
            flog_err_sys(EC_LIB_SOCKET,
		      "setsockopt(IPV6_LEAVE_GROUP) on interface '%s': %s",
                      ifp->name, safe_strerror(errno));
    }

    update_interface_metric(ifp);

    debugf(BABEL_DEBUG_COMMON,"Upped network %s (%s, cost=%d%s).",
           ifp->name,
           (babel_ifp->flags & BABEL_IF_WIRED) ? "wired" : "wireless",
           babel_ifp->cost,
           babel_ifp->ipv4 ? ", IPv4" : "");

    return 1;
}

/* Send retraction to all, and reset all interfaces statistics. */
void
babel_interface_close_all(void)
{
    struct vrf *vrf = vrf_lookup_by_id(VRF_DEFAULT);
    struct interface *ifp = NULL;

    FOR_ALL_INTERFACES(vrf, ifp) {
        if(!if_up(ifp))
            continue;
        send_wildcard_retraction(ifp);
        /* Make sure that we expire quickly from our neighbours'
         association caches. */
        send_hello_noupdate(ifp, 10);
        flushbuf(ifp);
        usleep(roughly(1000));
        gettime(&babel_now);
    }
    FOR_ALL_INTERFACES(vrf, ifp) {
        if(!if_up(ifp))
            continue;
        /* Make sure they got it. */
        send_wildcard_retraction(ifp);
        send_hello_noupdate(ifp, 1);
        flushbuf(ifp);
        usleep(roughly(10000));
        gettime(&babel_now);
        interface_reset(ifp);
    }
}

/* return "true" if address is one of our ipv6 addresses */
int
is_interface_ll_address(struct interface *ifp, const unsigned char *address)
{
    struct connected *connected;
    struct listnode *node;

    if(!if_up(ifp))
        return 0;

    FOR_ALL_INTERFACES_ADDRESSES(ifp, connected, node) {
	    if (connected->address->family == AF_INET6
		&& memcmp(&connected->address->u.prefix6, address,
			  IPV6_MAX_BYTELEN)
			   == 0)
		    return 1;
    }

    return 0;
}

static void
show_babel_interface_sub (struct vty *vty, struct interface *ifp)
{
  int is_up;
  babel_interface_nfo *babel_ifp;

  vty_out (vty, "%s is %s\n", ifp->name,
    ((is_up = if_is_operative(ifp)) ? "up" : "down"));
  vty_out (vty, "  ifindex %u, MTU %u bytes %s\n",
    ifp->ifindex, MIN(ifp->mtu, ifp->mtu6), if_flag_dump(ifp->flags));

  if (!IS_ENABLE(ifp))
  {
    vty_out (vty, "  Babel protocol is not enabled on this interface\n");
    return;
  }
  if (!is_up)
  {
    vty_out (vty,
               "  Babel protocol is enabled, but not running on this interface\n");
    return;
  }
  babel_ifp = babel_get_if_nfo (ifp);
  vty_out (vty, "  Babel protocol is running on this interface\n");
  vty_out (vty, "  Operating mode is \"%s\"\n",
           CHECK_FLAG(babel_ifp->flags, BABEL_IF_WIRED) ? "wired" : "wireless");
  vty_out (vty, "  Split horizon mode is %s\n",
           CHECK_FLAG(babel_ifp->flags, BABEL_IF_SPLIT_HORIZON) ? "On" : "Off");
  vty_out (vty, "  Hello interval is %u ms\n", babel_ifp->hello_interval);
  vty_out (vty, "  Update interval is %u ms\n", babel_ifp->update_interval);
  vty_out (vty, "  Rxcost multiplier is %u\n", babel_ifp->cost);
}

DEFUN (show_babel_interface,
       show_babel_interface_cmd,
       "show babel interface [IFNAME]",
       SHOW_STR
       "Babel information\n"
       "Interface information\n"
       "Interface\n")
{
  struct vrf *vrf = vrf_lookup_by_id(VRF_DEFAULT);
  struct interface *ifp;

  if (argc == 3)
  {
    FOR_ALL_INTERFACES (vrf, ifp)
      show_babel_interface_sub (vty, ifp);
    return CMD_SUCCESS;
  }
  if ((ifp = if_lookup_by_name (argv[3]->arg, VRF_DEFAULT)) == NULL)
  {
    vty_out (vty, "No such interface name\n");
    return CMD_WARNING;
  }
  show_babel_interface_sub (vty, ifp);
  return CMD_SUCCESS;
}

static void
show_babel_neighbour_sub (struct vty *vty, struct neighbour *neigh)
{
    vty_out (vty,
             "Neighbour %s dev %s reach %04x rxcost %d txcost %d rtt %s rttcost %d%s.\n",
             format_address(neigh->address),
             neigh->ifp->name,
             neigh->reach,
             neighbour_rxcost(neigh),
             neigh->txcost,
             format_thousands(neigh->rtt),
             neighbour_rttcost(neigh),
             if_up(neigh->ifp) ? "" : " (down)");
}

DEFUN (show_babel_neighbour,
       show_babel_neighbour_cmd,
       "show babel neighbor [IFNAME]",
       SHOW_STR
       "Babel information\n"
       "Print neighbors\n"
       "Interface\n")
{
    struct neighbour *neigh;
    struct interface *ifp;

    if (argc == 3) {
        FOR_ALL_NEIGHBOURS(neigh) {
            show_babel_neighbour_sub(vty, neigh);
        }
        return CMD_SUCCESS;
    }
    if ((ifp = if_lookup_by_name (argv[3]->arg, VRF_DEFAULT)) == NULL)
    {
        vty_out (vty, "No such interface name\n");
        return CMD_WARNING;
    }
    FOR_ALL_NEIGHBOURS(neigh) {
        if(ifp->ifindex == neigh->ifp->ifindex) {
            show_babel_neighbour_sub(vty, neigh);
        }
    }
    return CMD_SUCCESS;
}

static int
babel_prefix_eq(struct prefix *prefix, unsigned char *p, int plen)
{
    if(prefix->family == AF_INET6) {
	    if (prefix->prefixlen != plen
		|| memcmp(&prefix->u.prefix6, p, IPV6_MAX_BYTELEN) != 0)
		    return 0;
    } else if(prefix->family == AF_INET) {
	    if (plen < 96 || !v4mapped(p) || prefix->prefixlen != plen - 96
		|| memcmp(&prefix->u.prefix4, p + 12, IPV4_MAX_BYTELEN) != 0)
		    return 0;
    } else {
        return 0;
    }

    return 1;
}

static void
show_babel_routes_sub(struct babel_route *route, struct vty *vty,
                      struct prefix *prefix)
{
	const unsigned char *nexthop =
		memcmp(route->nexthop, route->neigh->address, IPV6_MAX_BYTELEN)
				== 0
			? NULL
			: route->nexthop;
	char channels[100];

	if (prefix
	    && !babel_prefix_eq(prefix, route->src->prefix, route->src->plen))
		return;

	if (route->channels[0] == 0)
		channels[0] = '\0';
	else {
		int k, j = 0;
		snprintf(channels, sizeof(channels), " chan (");
		j = strlen(channels);
		for (k = 0; k < DIVERSITY_HOPS; k++) {
			if (route->channels[k] == 0)
				break;
			if (k > 0)
				channels[j++] = ',';
			snprintf(channels + j, 100 - j, "%u",
				 route->channels[k]);
			j = strlen(channels);
		}
		snprintf(channels + j, 100 - j, ")");
		if (k == 0)
			channels[0] = '\0';
    }

    vty_out (vty,
            "%s metric %d refmetric %d id %s seqno %d%s age %d via %s neigh %s%s%s%s\n",
            format_prefix(route->src->prefix, route->src->plen),
            route_metric(route), route->refmetric,
            format_eui64(route->src->id),
            (int)route->seqno,
            channels,
            (int)(babel_now.tv_sec - route->time),
            route->neigh->ifp->name,
            format_address(route->neigh->address),
            nexthop ? " nexthop " : "",
            nexthop ? format_address(nexthop) : "",
            route->installed ? " (installed)" : route_feasible(route) ? " (feasible)" : "");
}

static void
show_babel_xroutes_sub (struct xroute *xroute, struct vty *vty,
                        struct prefix *prefix)
{
    if(prefix && !babel_prefix_eq(prefix, xroute->prefix, xroute->plen))
        return;

    vty_out (vty, "%s metric %d (exported)\n",
            format_prefix(xroute->prefix, xroute->plen),
            xroute->metric);
}

DEFUN (show_babel_route,
       show_babel_route_cmd,
       "show babel route",
       SHOW_STR
       "Babel information\n"
       "Babel internal routing table\n")
{
    struct route_stream *routes = NULL;
    struct xroute_stream *xroutes = NULL;
    routes = route_stream(0);
    if(routes) {
        while(1) {
            struct babel_route *route = route_stream_next(routes);
            if(route == NULL)
                break;
            show_babel_routes_sub(route, vty, NULL);
        }
        route_stream_done(routes);
    } else {
        flog_err(EC_BABEL_MEMORY, "Couldn't allocate route stream.");
    }
    xroutes = xroute_stream();
    if(xroutes) {
        while(1) {
            struct xroute *xroute = xroute_stream_next(xroutes);
            if(xroute == NULL)
                break;
            show_babel_xroutes_sub(xroute, vty, NULL);
        }
        xroute_stream_done(xroutes);
    } else {
        flog_err(EC_BABEL_MEMORY, "Couldn't allocate route stream.");
    }
    return CMD_SUCCESS;
}

DEFUN (show_babel_route_prefix,
       show_babel_route_prefix_cmd,
       "show babel route <A.B.C.D/M|X:X::X:X/M>",
       SHOW_STR
       "Babel information\n"
       "Babel internal routing table\n"
       "IPv4 prefix <network>/<length>\n"
       "IPv6 prefix <network>/<length>\n")
{
    struct route_stream *routes = NULL;
    struct xroute_stream *xroutes = NULL;
    struct prefix prefix;
    int ret;

    ret = str2prefix(argv[3]->arg, &prefix);
    if(ret == 0) {
      vty_out (vty, "%% Malformed address\n");
      return CMD_WARNING;
    }

    routes = route_stream(0);
    if(routes) {
        while(1) {
            struct babel_route *route = route_stream_next(routes);
            if(route == NULL)
                break;
            show_babel_routes_sub(route, vty, &prefix);
        }
        route_stream_done(routes);
    } else {
        flog_err(EC_BABEL_MEMORY, "Couldn't allocate route stream.");
    }
    xroutes = xroute_stream();
    if(xroutes) {
        while(1) {
            struct xroute *xroute = xroute_stream_next(xroutes);
            if(xroute == NULL)
                break;
            show_babel_xroutes_sub(xroute, vty, &prefix);
        }
        xroute_stream_done(xroutes);
    } else {
        flog_err(EC_BABEL_MEMORY, "Couldn't allocate route stream.");
    }
    return CMD_SUCCESS;
}


DEFUN (show_babel_route_addr,
       show_babel_route_addr_cmd,
       "show babel route A.B.C.D",
       SHOW_STR
       "Babel information\n"
       "Babel internal routing table\n"
       "IPv4 address <network>/<length>\n")
{
    struct in_addr addr;
    char buf[INET_ADDRSTRLEN + 8];
    char buf1[INET_ADDRSTRLEN + 8];
    struct route_stream *routes = NULL;
    struct xroute_stream *xroutes = NULL;
    struct prefix prefix;
    int ret;

    ret = inet_aton (argv[3]->arg, &addr);
    if (ret <= 0) {
        vty_out (vty, "%% Malformed address\n");
        return CMD_WARNING;
    }

    /* Quagga has no convenient prefix constructors. */
    snprintf(buf, sizeof(buf), "%s/%d",
	     inet_ntop(AF_INET, &addr, buf1, sizeof(buf1)), 32);

    ret = str2prefix(buf, &prefix);
    if (ret == 0) {
        vty_out (vty, "%% Parse error -- this shouldn't happen\n");
        return CMD_WARNING;
    }

    routes = route_stream(0);
    if(routes) {
        while(1) {
            struct babel_route *route = route_stream_next(routes);
            if(route == NULL)
                break;
            show_babel_routes_sub(route, vty, &prefix);
        }
        route_stream_done(routes);
    } else {
        flog_err(EC_BABEL_MEMORY, "Couldn't allocate route stream.");
    }
    xroutes = xroute_stream();
    if(xroutes) {
        while(1) {
            struct xroute *xroute = xroute_stream_next(xroutes);
            if(xroute == NULL)
                break;
            show_babel_xroutes_sub(xroute, vty, &prefix);
        }
        xroute_stream_done(xroutes);
    } else {
        flog_err(EC_BABEL_MEMORY, "Couldn't allocate route stream.");
    }
    return CMD_SUCCESS;
}

DEFUN (show_babel_route_addr6,
       show_babel_route_addr6_cmd,
       "show babel route X:X::X:X",
       SHOW_STR
       "Babel information\n"
       "Babel internal routing table\n"
       "IPv6 address <network>/<length>\n")
{
    struct in6_addr addr;
    char buf1[INET6_ADDRSTRLEN];
    char buf[INET6_ADDRSTRLEN + 8];
    struct route_stream *routes = NULL;
    struct xroute_stream *xroutes = NULL;
    struct prefix prefix;
    int ret;

    ret = inet_pton (AF_INET6, argv[3]->arg, &addr);
    if (ret <= 0) {
        vty_out (vty, "%% Malformed address\n");
        return CMD_WARNING;
    }

    /* Quagga has no convenient prefix constructors. */
    snprintf(buf, sizeof(buf), "%s/%d",
             inet_ntop(AF_INET6, &addr, buf1, sizeof(buf1)), 128);

    ret = str2prefix(buf, &prefix);
    if (ret == 0) {
        vty_out (vty, "%% Parse error -- this shouldn't happen\n");
        return CMD_WARNING;
    }

    routes = route_stream(0);
    if(routes) {
        while(1) {
            struct babel_route *route = route_stream_next(routes);
            if(route == NULL)
                break;
            show_babel_routes_sub(route, vty, &prefix);
        }
        route_stream_done(routes);
    } else {
        flog_err(EC_BABEL_MEMORY, "Couldn't allocate route stream.");
    }
    xroutes = xroute_stream();
    if(xroutes) {
        while(1) {
            struct xroute *xroute = xroute_stream_next(xroutes);
            if(xroute == NULL)
                break;
            show_babel_xroutes_sub(xroute, vty, &prefix);
        }
        xroute_stream_done(xroutes);
    } else {
        flog_err(EC_BABEL_MEMORY, "Couldn't allocate route stream.");
    }
    return CMD_SUCCESS;
}

DEFUN (show_babel_parameters,
       show_babel_parameters_cmd,
       "show babel parameters",
       SHOW_STR
       "Babel information\n"
       "Configuration information\n")
{
    struct babel *babel_ctx;

    vty_out (vty, "    -- Babel running configuration --\n");
    show_babel_main_configuration(vty);

    babel_ctx = babel_lookup();
    if (babel_ctx) {
        vty_out (vty, "    -- distribution lists --\n");
        config_show_distribute(vty, babel_ctx->distribute_ctx);
    }
    return CMD_SUCCESS;
}

void
babel_if_init(void)
{
    /* initialize interface list */
    hook_register_prio(if_add, 0, babel_if_new_hook);
    hook_register_prio(if_del, 0, babel_if_delete_hook);

    babel_enable_if = vector_init (1);

    /* install interface node and commands */
    if_cmd_init(interface_config_write);

    install_element(BABEL_NODE, &babel_network_cmd);
    install_element(BABEL_NODE, &no_babel_network_cmd);
    install_element(INTERFACE_NODE, &babel_split_horizon_cmd);
    install_element(INTERFACE_NODE, &babel_set_wired_cmd);
    install_element(INTERFACE_NODE, &babel_set_wireless_cmd);
    install_element(INTERFACE_NODE, &babel_set_hello_interval_cmd);
    install_element(INTERFACE_NODE, &babel_set_update_interval_cmd);
    install_element(INTERFACE_NODE, &babel_set_rxcost_cmd);
    install_element(INTERFACE_NODE, &babel_set_channel_cmd);
    install_element(INTERFACE_NODE, &babel_set_rtt_decay_cmd);
    install_element(INTERFACE_NODE, &babel_set_rtt_min_cmd);
    install_element(INTERFACE_NODE, &babel_set_rtt_max_cmd);
    install_element(INTERFACE_NODE, &babel_set_max_rtt_penalty_cmd);
    install_element(INTERFACE_NODE, &babel_set_enable_timestamps_cmd);

    /* "show babel ..." commands */
    install_element(VIEW_NODE, &show_babel_interface_cmd);
    install_element(VIEW_NODE, &show_babel_neighbour_cmd);
    install_element(VIEW_NODE, &show_babel_route_cmd);
    install_element(VIEW_NODE, &show_babel_route_prefix_cmd);
    install_element(VIEW_NODE, &show_babel_route_addr_cmd);
    install_element(VIEW_NODE, &show_babel_route_addr6_cmd);
    install_element(VIEW_NODE, &show_babel_parameters_cmd);
}

/* hooks: functions called respectively when struct interface is
 created or deleted. */
static int
babel_if_new_hook (struct interface *ifp)
{
    ifp->info = babel_interface_allocate();
    return 0;
}

static int
babel_if_delete_hook (struct interface *ifp)
{
    babel_interface_free(ifp->info);
    ifp->info = NULL;
    return 0;
}

/* Output an "interface" section for each of the known interfaces with
babeld-specific statement lines where appropriate. */
static int
interface_config_write (struct vty *vty)
{
    struct vrf *vrf = vrf_lookup_by_id(VRF_DEFAULT);
    struct interface *ifp;
    int write = 0;

    FOR_ALL_INTERFACES (vrf, ifp) {
        if_vty_config_start(vty, ifp);
        if (ifp->desc)
            vty_out (vty, " description %s\n",ifp->desc);
        babel_interface_nfo *babel_ifp = babel_get_if_nfo (ifp);
        /* wireless is the default*/
        if (CHECK_FLAG (babel_ifp->flags, BABEL_IF_WIRED))
        {
            vty_out (vty, " babel wired\n");
            write++;
        }
        if (babel_ifp->hello_interval != BABEL_DEFAULT_HELLO_INTERVAL)
        {
            vty_out (vty, " babel hello-interval %u\n",
                       babel_ifp->hello_interval);
            write++;
        }
        if (babel_ifp->update_interval != BABEL_DEFAULT_UPDATE_INTERVAL)
        {
            vty_out (vty, " babel update-interval %u\n",
                       babel_ifp->update_interval);
            write++;
        }
	if (CHECK_FLAG(babel_ifp->flags, BABEL_IF_TIMESTAMPS)) {
		vty_out(vty, " babel enable-timestamps\n");
		write++;
	}
	if (babel_ifp->max_rtt_penalty != BABEL_DEFAULT_MAX_RTT_PENALTY) {
		vty_out(vty, " babel max-rtt-penalty %u\n",
			babel_ifp->max_rtt_penalty);
		write++;
	}
	if (babel_ifp->rtt_decay != BABEL_DEFAULT_RTT_DECAY) {
		vty_out(vty, " babel rtt-decay %u\n", babel_ifp->rtt_decay);
		write++;
	}
	if (babel_ifp->rtt_min != BABEL_DEFAULT_RTT_MIN) {
		vty_out(vty, " babel rtt-min %u\n", babel_ifp->rtt_min / 1000);
		write++;
	}
	if (babel_ifp->rtt_max != BABEL_DEFAULT_RTT_MAX) {
		vty_out(vty, " babel rtt-max %u\n", babel_ifp->rtt_max / 1000);
		write++;
	}
	/* Some parameters have different defaults for wired/wireless. */
	if (CHECK_FLAG (babel_ifp->flags, BABEL_IF_WIRED)) {
            if (!CHECK_FLAG (babel_ifp->flags, BABEL_IF_SPLIT_HORIZON)) {
                vty_out (vty, " no babel split-horizon\n");
                write++;
            }
            if (babel_ifp->cost != BABEL_DEFAULT_RXCOST_WIRED) {
                vty_out (vty, " babel rxcost %u\n", babel_ifp->cost);
                write++;
            }
            if (babel_ifp->channel == BABEL_IF_CHANNEL_INTERFERING) {
                vty_out (vty, " babel channel interfering\n");
                write++;
            } else if(babel_ifp->channel != BABEL_IF_CHANNEL_NONINTERFERING) {
                vty_out (vty, " babel channel %d\n",babel_ifp->channel);
                write++;
            }
        } else {
            if (CHECK_FLAG (babel_ifp->flags, BABEL_IF_SPLIT_HORIZON)) {
                vty_out (vty, " babel split-horizon\n");
                write++;
            }
            if (babel_ifp->cost != BABEL_DEFAULT_RXCOST_WIRELESS) {
                vty_out (vty, " babel rxcost %u\n", babel_ifp->cost);
                write++;
            }
            if (babel_ifp->channel == BABEL_IF_CHANNEL_NONINTERFERING) {
                vty_out (vty, " babel channel noninterfering\n");
                write++;
            } else if(babel_ifp->channel != BABEL_IF_CHANNEL_INTERFERING) {
                vty_out (vty, " babel channel %d\n",babel_ifp->channel);
                write++;
            }
        }
        if_vty_config_end(vty);
        write++;
    }
    return write;
}

/* Output a "network" statement line for each of the enabled interfaces. */
int
babel_enable_if_config_write (struct vty * vty)
{
    unsigned int i, lines = 0;
    char *str;

    for (i = 0; i < vector_active (babel_enable_if); i++)
        if ((str = vector_slot (babel_enable_if, i)) != NULL)
        {
            vty_out (vty, " network %s\n", str);
            lines++;
        }
    return lines;
}

/* functions to allocate or free memory for a babel_interface_nfo, filling
 needed fields */
static babel_interface_nfo *
babel_interface_allocate (void)
{
    babel_interface_nfo *babel_ifp;
    babel_ifp = XCALLOC(MTYPE_BABEL_IF, sizeof(babel_interface_nfo));
    /* All flags are unset */
    babel_ifp->bucket_time = babel_now.tv_sec;
    babel_ifp->bucket = BUCKET_TOKENS_MAX;
    babel_ifp->hello_seqno = (frr_weak_random() & 0xFFFF);
    babel_ifp->rtt_decay = BABEL_DEFAULT_RTT_DECAY;
    babel_ifp->rtt_min = BABEL_DEFAULT_RTT_MIN;
    babel_ifp->rtt_max = BABEL_DEFAULT_RTT_MAX;
    babel_ifp->max_rtt_penalty = BABEL_DEFAULT_MAX_RTT_PENALTY;
    babel_ifp->hello_interval = BABEL_DEFAULT_HELLO_INTERVAL;
    babel_ifp->update_interval = BABEL_DEFAULT_UPDATE_INTERVAL;
    babel_ifp->channel = BABEL_IF_CHANNEL_INTERFERING;
    babel_set_wired_internal(babel_ifp, 0);

    return babel_ifp;
}

static void
babel_interface_free (babel_interface_nfo *babel_ifp)
{
    XFREE(MTYPE_BABEL_IF, babel_ifp);
}