path: root/extras/router-plugin/devices/rtnetlink/netns.c

/*
 * Copyright (c) 2021 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <stddef.h>
#include <vlib/unix/unix.h>
#include <vlib/vlib.h>
#include <vnet/ethernet/ethernet.h>
#include <vnet/ip/format.h>
#include <vnet/ip/ip4_packet.h>
#include <vnet/ip/ip6_packet.h>

#include "netns.h"
#include <hicn/util/sstrncpy.h>

/* Enable some RTA values debug */
//#define RTNL_CHECK

#define is_nonzero(x)                                                         \
  ({                                                                          \
    u8 __is_zero_zero[sizeof (x)] = {};                                       \
    memcmp (__is_zero_zero, &x, sizeof (x));                                  \
  })

typedef struct
{
  u8 type;    // Attribute identifier
  u8 unique;  // Part of the values uniquely identifying an entry
  u16 offset; // Offset where stored in struct
  u16 size;   // Length of the attribute
} rtnl_mapping_t;

#define ns_foreach_ifla                                                       \
  _ (IFLA_ADDRESS, hwaddr)                                                    \
  _ (IFLA_BROADCAST, broadcast)                                               \
  _ (IFLA_IFNAME, ifname)                                                     \
  _ (IFLA_MASTER, master)                                                     \
  _ (IFLA_MTU, mtu)                                                           \
  _ (IFLA_QDISC, qdisc)

static rtnl_mapping_t ns_ifmap[] = {
#define _(t, e)                                                               \
  { .type = t,                                                                \
    .offset = offsetof (ns_link_t, e),                                        \
    .size = sizeof (((ns_link_t *) 0)->e) },
  ns_foreach_ifla
#undef _
  { .type = 0 }
};

u8 *
format_ns_link (u8 *s, va_list *args)
{
  ns_link_t *l = va_arg (*args, ns_link_t *);
  s = format (s, "%s index %u", l->ifname, l->ifi.ifi_index);
  return s;
}

#define ns_foreach_rta                                                        \
  _ (RTA_DST, dst, 1)                                                         \
  _ (RTA_SRC, src, 1)                                                         \
  _ (RTA_GATEWAY, gateway, 1)                                                 \
  _ (RTA_IIF, iif, 1)                                                         \
  _ (RTA_OIF, oif, 1)                                                         \
  _ (RTA_PREFSRC, prefsrc, 0)                                                 \
  _ (RTA_TABLE, table, 0)                                                     \
  _ (RTA_PRIORITY, priority, 0)                                               \
  _ (RTA_CACHEINFO, cacheinfo, 0)                                             \
  _ (RTA_ENCAP, encap, 1)

static rtnl_mapping_t ns_routemap[] = {
#define _(t, e, u)                                                            \
  { .type = t,                                                                \
    .unique = u,                                                              \
    .offset = offsetof (ns_route_t, e),                                       \
    .size = sizeof (((ns_route_t *) 0)->e) },
  ns_foreach_rta
#undef _
  { .type = 0 }
};

u8 *
format_ns_route (u8 *s, va_list *args)
{
  ns_route_t *r = va_arg (*args, ns_route_t *);
  void *format_ip =
    r->rtm.rtm_family == AF_INET ? format_ip4_address : format_ip6_address;
  s = format (s, "%U/%d", format_ip, r->dst, r->rtm.rtm_dst_len);
  if (r->rtm.rtm_src_len)
    s = format (s, " from %U/%d", format_ip, r->src, r->rtm.rtm_src_len);
  if (is_nonzero (r->gateway))
    s = format (s, " via %U", format_ip, r->gateway);
  if (r->iif)
    s = format (s, " iif %d", r->iif);
  if (r->oif)
    s = format (s, " oif %d", r->oif);
  if (is_nonzero (r->prefsrc))
    s = format (s, " src %U", format_ip, r->prefsrc);
  if (r->table)
    s = format (s, " table %d", r->table);
  if (r->priority)
    s = format (s, " priority %u", r->priority);
  return s;
}

#define ns_foreach_ifaddr                                                     \
  _ (IFA_ADDRESS, addr, 1)                                                    \
  _ (IFA_LOCAL, local, 1)                                                     \
  _ (IFA_LABEL, label, 0)                                                     \
  _ (IFA_BROADCAST, broadcast, 0)                                             \
  _ (IFA_ANYCAST, anycast, 0)                                                 \
  _ (IFA_CACHEINFO, cacheinfo, 0)

static rtnl_mapping_t ns_addrmap[] = {
#define _(t, e, u)                                                            \
  { .type = t,                                                                \
    .unique = u,                                                              \
    .offset = offsetof (ns_addr_t, e),                                        \
    .size = sizeof (((ns_addr_t *) 0)->e) },
  ns_foreach_ifaddr
#undef _
  { .type = 0 }
};

u8 *
format_ns_addr (u8 *s, va_list *args)
{
  ns_addr_t *a = va_arg (*args, ns_addr_t *);
  void *format_ip =
    a->ifaddr.ifa_family == AF_INET ? format_ip4_address : format_ip6_address;
  s = format (s, "%U/%d", format_ip, a->addr, a->ifaddr.ifa_prefixlen);
  if (is_nonzero (a->label))
    s = format (s, " dev %s", a->label);
  if (is_nonzero (a->broadcast))
    s = format (s, " broadcast %U", format_ip, a->broadcast);
  if (is_nonzero (a->anycast))
    s = format (s, " anycast %U", format_ip, a->anycast);
  if (is_nonzero (a->local))
    s = format (s, " local %U", format_ip, a->local);
  return s;
}

#ifndef NDA_RTA
#define NDA_RTA(r)                                                            \
  ((struct rtattr *) (((char *) (r)) + NLMSG_ALIGN (sizeof (struct ndmsg))))
#define NDA_PAYLOAD(n) NLMSG_PAYLOAD (n, sizeof (struct ndmsg))
#endif

#define ns_foreach_neigh                                                      \
  _ (NDA_DST, dst, 1)                                                         \
  _ (NDA_LLADDR, lladdr, 0)                                                   \
  _ (NDA_PROBES, probes, 0)                                                   \
  _ (NDA_CACHEINFO, cacheinfo, 0)

static rtnl_mapping_t ns_neighmap[] = {
#define _(t, e, u)                                                            \
  { .type = t,                                                                \
    .unique = u,                                                              \
    .offset = offsetof (ns_neigh_t, e),                                       \
    .size = sizeof (((ns_neigh_t *) 0)->e) },
  ns_foreach_neigh
#undef _
  { .type = 0 }
};

u8 *
format_ns_neigh (u8 *s, va_list *args)
{
  ns_neigh_t *n = va_arg (*args, ns_neigh_t *);
  void *format_ip =
    n->nd.ndm_family == AF_INET ? format_ip4_address : format_ip6_address;
  s = format (s, "%U", format_ip, n->dst);
  if (is_nonzero (n->lladdr))
    s = format (s, " lladdr %U", format_ethernet_address, n->lladdr);
  if (n->probes)
    s = format (s, " probes %d", n->probes);
  return s;
}

typedef struct
{
  void (*notify) (void *obj, netns_type_t type, u32 flags, uword opaque);
  uword opaque;
  u32 netns_index;
} netns_handle_t;

typedef struct
{
  netns_t netns;
  u32 rtnl_handle;
  u32 subscriber_count;
} netns_p;

typedef struct
{
  netns_p *netnss;
  netns_handle_t *handles;
} netns_main_t;

netns_main_t netns_main;

static int
rtnl_parse_rtattr (struct rtattr *db[], size_t max, struct rtattr *rta,
		   size_t len)
{
  for (; RTA_OK (rta, len); rta = RTA_NEXT (rta, len))
    {
      if (rta->rta_type <= max)
	db[rta->rta_type] = rta;
#ifdef RTNL_CHECK
      else
	clib_warning ("RTA type too high: %d", rta->rta_type);
#endif
    }

  if (len)
    {
      clib_warning ("rattr lenght mistmatch %d %d len", (int) len,
		    (int) rta->rta_len);
      return -1;
    }
  return 0;
}

/*
 * Debug function to display when
 * we receive an RTA that I forgot in
 * the mapping table (there are so many of them).
 */
#ifdef RTNL_CHECK
static void
rtnl_entry_check (struct rtattr *rtas[], size_t rta_len, rtnl_mapping_t map[],
		  char *logstr)
{
  int i;
  for (i = 0; i < rta_len; i++)
    {
      if (!rtas[i])
	continue;

      rtnl_mapping_t *m = map;
      for (m = map; m->type; m++)
	{
	  if (m->type == rtas[i]->rta_type)
	    break;
	}
      if (!m->type)
	clib_warning ("Unknown RTA type %d (%s)", rtas[i]->rta_type, logstr);
    }
}
#endif

/*
 * Check if the provided entry matches the parsed and unique rtas
 */
static int
rtnl_entry_match (void *entry, struct rtattr *rtas[], rtnl_mapping_t map[])
{
  u8 zero[1024] = {};
  for (; map->type != 0; map++)
    {
      struct rtattr *rta = rtas[map->type];
      size_t rta_len = rta ? RTA_PAYLOAD (rta) : 0;
      if (!map->unique)
	continue;

      if (rta && RTA_PAYLOAD (rta) > map->size)
	{
	  clib_warning ("rta (type=%d len=%d) too long (max %d)",
			rta->rta_type, rta->rta_len, map->size);
	  return -1;
	}

      if ((rta && memcmp (RTA_DATA (rta), entry + map->offset, rta_len)) ||
	  memcmp (entry + map->offset + rta_len, zero, map->size - rta_len))
	{
	  return 0;
	}
    }
  return 1;
}

static int
rtnl_entry_set (void *entry, struct rtattr *rtas[], rtnl_mapping_t map[],
		int init)
{
  for (; map->type != 0; map++)
    {

      struct rtattr *rta = rtas[map->type];

      if (map->type == RTA_ENCAP && rta)
	{
	  /*Data of RTA_ENCAP is a pointer to rta attributes for MPLS*/
	  rta = (struct rtattr *) RTA_DATA (rta);
	  if (RTA_PAYLOAD (rta) > map->size)
	    {
	      clib_warning ("rta (type=%d len=%d) too long (max %d)",
			    rta->rta_type, rta->rta_len, map->size);
	      return -1;
	    }
	  memcpy (entry + map->offset, RTA_DATA (rta), map->size);
	  memset (entry + map->offset + map->size, 0, 0);
	}
      else if (rta)
	{
	  if (RTA_PAYLOAD (rta) > map->size)
	    {
	      clib_warning ("rta (type=%d len=%d) too long (max %d)",
			    rta->rta_type, rta->rta_len, map->size);
	      return -1;
	    }
	  memcpy (entry + map->offset, RTA_DATA (rta), RTA_PAYLOAD (rta));
	  memset (entry + map->offset + RTA_PAYLOAD (rta), 0,
		  map->size - RTA_PAYLOAD (rta));
	}
      else if (init)
	{
	  memset (entry + map->offset, 0, map->size);
	}
    }
  return 0;
}

void
netns_notify (netns_p *ns, void *obj, netns_type_t type, u32 flags)
{
  netns_main_t *nm = &netns_main;
  netns_handle_t *h;
  pool_foreach (h, nm->handles, {
    if (h->netns_index == (ns - nm->netnss) && h->notify)
      h->notify (obj, type, flags, h->opaque);
  })
    ;
}

static_always_inline int
mask_match (void *a, void *b, void *mask, size_t len)
{
  u8 *va = (u8 *) a;
  u8 *vb = (u8 *) b;
  u8 *vm = (u8 *) mask;
  while (len--)
    {
      if ((va[len] ^ vb[len]) & vm[len])
	return 0;
    }
  return 1;
}

static ns_link_t *
ns_get_link (netns_p *ns, struct ifinfomsg *ifi, struct rtattr *rtas[])
{
  ns_link_t *link;
  pool_foreach (link, ns->netns.links, {
    if (ifi->ifi_index == link->ifi.ifi_index)
      return link;
  })
    ;
  return NULL;
}

static int
ns_rcv_link (netns_p *ns, struct nlmsghdr *hdr)
{
  ns_link_t *link;
  struct ifinfomsg *ifi;
  struct rtattr *rtas[IFLA_MAX + 1] = {};
  size_t datalen = hdr->nlmsg_len - NLMSG_ALIGN (sizeof (*hdr));

  if (datalen < sizeof (*ifi))
    return -1;

  ifi = NLMSG_DATA (hdr);
  if ((datalen > NLMSG_ALIGN (sizeof (*ifi))) &&
      rtnl_parse_rtattr (rtas, IFLA_MAX, IFLA_RTA (ifi), IFLA_PAYLOAD (hdr)))
    {
      return -1;
    }
#ifdef RTNL_CHECK
  rtnl_entry_check (rtas, IFLA_MAX + 1, ns_ifmap, "link");
#endif

  link = ns_get_link (ns, ifi, rtas);

  if (hdr->nlmsg_type == RTM_DELLINK)
    {
      if (!link)
	return -1;
      pool_put (ns->netns.links, link);
      netns_notify (ns, link, NETNS_TYPE_LINK, NETNS_F_DEL);
      return 0;
    }

  if (!link)
    {
      pool_get (ns->netns.links, link);
      rtnl_entry_set (link, rtas, ns_ifmap, 1);
    }
  else
    {
      rtnl_entry_set (link, rtas, ns_ifmap, 0);
    }

  link->ifi = *ifi;
  link->last_updated = vlib_time_now (vlib_get_main ());
  netns_notify (ns, link, NETNS_TYPE_LINK, NETNS_F_ADD);
  return 0;
}

static ns_route_t *
ns_get_route (netns_p *ns, struct rtmsg *rtm, struct rtattr *rtas[])
{
  ns_route_t *route;

  // This describes the values which uniquely identify a route
  struct rtmsg msg = { .rtm_family = 0xff,
		       .rtm_dst_len = 0xff,
		       .rtm_src_len = 0xff,
		       .rtm_table = 0xff,
		       .rtm_protocol = 0xff,
		       .rtm_type = 0xff };

  pool_foreach (route, ns->netns.routes, {
    if (mask_match (&route->rtm, rtm, &msg, sizeof (struct rtmsg)) &&
	rtnl_entry_match (route, rtas, ns_routemap))
      return route;
  })
    ;
  return NULL;
}

static int
ns_rcv_route (netns_p *ns, struct nlmsghdr *hdr)
{
  ns_route_t *route;
  struct rtmsg *rtm;
  struct rtattr *rtas[RTA_MAX + 1] = {};
  size_t datalen = hdr->nlmsg_len - NLMSG_ALIGN (sizeof (*hdr));

  if (datalen < sizeof (*rtm))
    return -1;

  rtm = NLMSG_DATA (hdr);
  if ((datalen > NLMSG_ALIGN (sizeof (*rtm))) &&
      rtnl_parse_rtattr (rtas, RTA_MAX, RTM_RTA (rtm), RTM_PAYLOAD (hdr)))
    {
      return -1;
    }
#ifdef RTNL_CHECK
  rtnl_entry_check (rtas, RTA_MAX + 1, ns_routemap, "route");
#endif
  route = ns_get_route (ns, rtm, rtas);

  if (hdr->nlmsg_type == RTM_DELROUTE)
    {
      if (!route)
	return -1;
      pool_put (ns->netns.routes, route);
      netns_notify (ns, route, NETNS_TYPE_ROUTE, NETNS_F_DEL);
      return 0;
    }

  if (!route)
    {
      pool_get (ns->netns.routes, route);
      memset (route, 0, sizeof (*route));
      rtnl_entry_set (route, rtas, ns_routemap, 1);
    }
  else
    {
      rtnl_entry_set (route, rtas, ns_routemap, 0);
    }

  route->rtm = *rtm;
  route->last_updated = vlib_time_now (vlib_get_main ());
  netns_notify (ns, route, NETNS_TYPE_ROUTE, NETNS_F_ADD);
  return 0;
}

static ns_addr_t *
ns_get_addr (netns_p *ns, struct ifaddrmsg *ifaddr, struct rtattr *rtas[])
{
  ns_addr_t *addr;

  // This describes the values which uniquely identify a route
  struct ifaddrmsg msg = {
    .ifa_family = 0xff,
    .ifa_prefixlen = 0xff,
  };

  pool_foreach (addr, ns->netns.addresses, {
    if (mask_match (&addr->ifaddr, ifaddr, &msg, sizeof (struct ifaddrmsg)) &&
	rtnl_entry_match (addr, rtas, ns_addrmap))
      return addr;
  })
    ;
  return NULL;
}

static int
ns_rcv_addr (netns_p *ns, struct nlmsghdr *hdr)
{
  ns_addr_t *addr;
  struct ifaddrmsg *ifaddr;
  struct rtattr *rtas[IFA_MAX + 1] = {};
  size_t datalen = hdr->nlmsg_len - NLMSG_ALIGN (sizeof (*hdr));

  if (datalen < sizeof (*ifaddr))
    return -1;

  ifaddr = NLMSG_DATA (hdr);
  if ((datalen > NLMSG_ALIGN (sizeof (*ifaddr))) &&
      rtnl_parse_rtattr (rtas, IFA_MAX, IFA_RTA (ifaddr), IFA_PAYLOAD (hdr)))
    {
      return -1;
    }
#ifdef RTNL_CHECK
  rtnl_entry_check (rtas, IFA_MAX + 1, ns_addrmap, "addr");
#endif
  addr = ns_get_addr (ns, ifaddr, rtas);

  if (hdr->nlmsg_type == RTM_DELADDR)
    {
      if (!addr)
	return -1;
      pool_put (ns->netns.addresses, addr);
      netns_notify (ns, addr, NETNS_TYPE_ADDR, NETNS_F_DEL);
      return 0;
    }

  if (!addr)
    {
      pool_get (ns->netns.addresses, addr);
      memset (addr, 0, sizeof (*addr));
      rtnl_entry_set (addr, rtas, ns_addrmap, 1);
    }
  else
    {
      rtnl_entry_set (addr, rtas, ns_addrmap, 0);
    }

  addr->ifaddr = *ifaddr;
  addr->last_updated = vlib_time_now (vlib_get_main ());
  netns_notify (ns, addr, NETNS_TYPE_ADDR, NETNS_F_ADD);
  return 0;
}

static ns_neigh_t *
ns_get_neigh (netns_p *ns, struct ndmsg *nd, struct rtattr *rtas[])
{
  ns_neigh_t *neigh;

  // This describes the values which uniquely identify a route
  struct ndmsg msg = {
    .ndm_family = 0xff,
    .ndm_ifindex = 0xff,
  };

  pool_foreach (neigh, ns->netns.neighbors, {
    if (mask_match (&neigh->nd, nd, &msg, sizeof (&msg)) &&
	rtnl_entry_match (neigh, rtas, ns_neighmap))
      return neigh;
  })
    ;
  return NULL;
}

static int
ns_rcv_neigh (netns_p *ns, struct nlmsghdr *hdr)
{
  ns_neigh_t *neigh;
  struct ndmsg *nd;
  struct rtattr *rtas[NDA_MAX + 1] = {};
  size_t datalen = hdr->nlmsg_len - NLMSG_ALIGN (sizeof (*hdr));

  if (datalen < sizeof (*nd))
    return -1;

  nd = NLMSG_DATA (hdr);
  if ((datalen > NLMSG_ALIGN (sizeof (*nd))) &&
      rtnl_parse_rtattr (rtas, NDA_MAX, NDA_RTA (nd), NDA_PAYLOAD (hdr)))
    {
      return -1;
    }
#ifdef RTNL_CHECK
  rtnl_entry_check (rtas, NDA_MAX + 1, ns_neighmap, "nd");
#endif
  neigh = ns_get_neigh (ns, nd, rtas);

  if (hdr->nlmsg_type == RTM_DELNEIGH)
    {
      if (!neigh)
	return -1;
      pool_put (ns->netns.neighbors, neigh);
      netns_notify (ns, neigh, NETNS_TYPE_NEIGH, NETNS_F_DEL);
      return 0;
    }

  if (!neigh)
    {
      pool_get (ns->netns.neighbors, neigh);
      memset (neigh, 0, sizeof (*neigh));
      rtnl_entry_set (neigh, rtas, ns_neighmap, 1);
    }
  else
    {
      rtnl_entry_set (neigh, rtas, ns_neighmap, 0);
    }

  neigh->nd = *nd;
  neigh->last_updated = vlib_time_now (vlib_get_main ());
  netns_notify (ns, neigh, NETNS_TYPE_NEIGH, NETNS_F_ADD);
  return 0;
}

#define ns_object_foreach                                                     \
  _ (neighbors, NETNS_TYPE_NEIGH)                                             \
  _ (routes, NETNS_TYPE_ROUTE)                                                \
  _ (addresses, NETNS_TYPE_ADDR)                                              \
  _ (links, NETNS_TYPE_LINK)

static void
ns_recv_error (rtnl_error_t err, uword o)
{
  // An error was received. Reset everything.
  netns_p *ns = &netns_main.netnss[o];
  u32 *indexes = 0;
  u32 *i = 0;

#define _(pool, type)                                                         \
  pool_foreach_index (*i, ns->netns.pool, { vec_add1 (indexes, *i); })        \
    vec_foreach (i, indexes)                                                  \
      {                                                                       \
	pool_put_index (ns->netns.pool, *i);                                  \
	netns_notify (ns, &ns->netns.pool[*i], type, NETNS_F_DEL);            \
      }                                                                       \
  vec_reset_length (indexes);

  ns_object_foreach

#undef _
    vec_free (indexes);
}

static void
ns_recv_rtnl (struct nlmsghdr *hdr, uword o)
{
  netns_p *ns = &netns_main.netnss[o];
  switch (hdr->nlmsg_type)
    {
    case RTM_NEWROUTE:
    case RTM_DELROUTE:
      ns_rcv_route (ns, hdr);
      break;
    case RTM_NEWLINK:
    case RTM_DELLINK:
      ns_rcv_link (ns, hdr);
      break;
    case RTM_NEWADDR:
    case RTM_DELADDR:
      ns_rcv_addr (ns, hdr);
      break;
    case RTM_NEWNEIGH:
    case RTM_DELNEIGH:
      ns_rcv_neigh (ns, hdr);
      break;
    default:
      clib_warning ("unknown rtnl type %d", hdr->nlmsg_type);
      break;
    }
}

static void
netns_destroy (netns_p *ns)
{
  netns_main_t *nm = &netns_main;
  rtnl_stream_close (ns->rtnl_handle);
  pool_put (nm->netnss, ns);
  pool_free (ns->netns.links);
  pool_free (ns->netns.addresses);
  pool_free (ns->netns.routes);
  pool_free (ns->netns.neighbors);
}

static netns_p *
netns_get (char *name)
{
  netns_main_t *nm = &netns_main;
  netns_p *ns;
  pool_foreach (ns, nm->netnss, {
    if (!strcmp (name, ns->netns.name))
      return ns;
  })
    ;

  if (strlen (name) > RTNL_NETNS_NAMELEN)
    return NULL;

  pool_get (nm->netnss, ns);
  rtnl_stream_t s = {
    .recv_message = ns_recv_rtnl,
    .error = ns_recv_error,
    .opaque = (uword) (ns - nm->netnss),
  };
  int rc = strcpy_s (s.name, sizeof (s.name), name);
  if (rc != EOK)
    return NULL;

  u32 handle;
  if ((handle = rtnl_stream_open (&s)) == ~0)
    {
      pool_put (nm->netnss, ns);
      return NULL;
    }

  rc = strcpy_s (ns->netns.name, sizeof (ns->netns.name), name);
  if (rc != EOK)
    return NULL;
  ns->netns.addresses = 0;
  ns->netns.links = 0;
  ns->netns.neighbors = 0;
  ns->netns.routes = 0;
  ns->subscriber_count = 0;
  ns->rtnl_handle = handle;
  return ns;
}

u32
netns_open (char *name, netns_sub_t *sub)
{
  netns_main_t *nm = &netns_main;
  netns_p *ns;
  netns_handle_t *p;
  if (!(ns = netns_get (name)))
    return ~0;

  pool_get (nm->handles, p);
  p->netns_index = ns - nm->netnss;
  p->notify = sub->notify;
  p->opaque = sub->opaque;
  ns->subscriber_count++;
  return p - nm->handles;
}

netns_t *
netns_getns (u32 handle)
{
  netns_main_t *nm = &netns_main;
  netns_handle_t *h = pool_elt_at_index (nm->handles, handle);
  netns_p *ns = pool_elt_at_index (nm->netnss, h->netns_index);
  return &ns->netns;
}

void
netns_close (u32 handle)
{
  netns_main_t *nm = &netns_main;
  netns_handle_t *h = pool_elt_at_index (nm->handles, handle);
  netns_p *ns = pool_elt_at_index (nm->netnss, h->netns_index);
  pool_put (h, nm->handles);
  ns->subscriber_count--;
  if (!ns->subscriber_count)
    netns_destroy (ns);
}

void
netns_callme (u32 handle, char del)
{
  netns_main_t *nm = &netns_main;
  netns_handle_t *h = pool_elt_at_index (nm->handles, handle);
  netns_p *ns = pool_elt_at_index (nm->netnss, h->netns_index);
  u32 i = 0;
  if (!h->notify)
    return;

#define _(pool, type)                                                         \
  pool_foreach_index (i, ns->netns.pool, {                                    \
    h->notify (&ns->netns.pool[i], type, del ? NETNS_F_DEL : NETNS_F_ADD,     \
	       h->opaque);                                                    \
  })                                                                          \
    ;

  ns_object_foreach
#undef _
}

u8 *
format_ns_object (u8 *s, va_list *args)
{
  netns_type_t t = va_arg (*args, netns_type_t);
  void *o = va_arg (*args, void *);
  switch (t)
    {
    case NETNS_TYPE_ADDR:
      return format (s, "addr %U", format_ns_addr, o);
    case NETNS_TYPE_ROUTE:
      return format (s, "route %U", format_ns_route, o);
    case NETNS_TYPE_LINK:
      return format (s, "link %U", format_ns_link, o);
    case NETNS_TYPE_NEIGH:
      return format (s, "neigh %U", format_ns_neigh, o);
    }
  return s;
}

u8 *
format_ns_flags (u8 *s, va_list *args)
{
  u32 flags = va_arg (*args, u32);
  if (flags & NETNS_F_ADD)
    s = format (s, "add");
  else if (flags & NETNS_F_DEL)
    s = format (s, "del");
  else
    s = format (s, "mod");
  return s;
}

clib_error_t *
netns_init (vlib_main_t *vm)
{
  netns_main_t *nm = &netns_main;
  nm->netnss = 0;
  nm->handles = 0;
  return 0;
}

VLIB_INIT_FUNCTION (netns_init);