Internet on FIRE

/*

 *        BIRD -- Linux Netlink Interface

 *

 *        (c) 1999--2000 Martin Mares <mj@ucw.cz>

 *

 *        Can be freely distributed and used under the terms of the GNU GPL.

 */

#include <stdio.h>

#include <unistd.h>

#include <fcntl.h>

#include <sys/socket.h>

#include <sys/uio.h>

#include <errno.h>

#undef LOCAL_DEBUG

#include "nest/bird.h"

#include "nest/route.h"

#include "nest/protocol.h"

#include "nest/iface.h"

#include "lib/alloca.h"

#include "lib/timer.h"

#include "lib/unix.h"

#include "lib/krt.h"

#include "lib/socket.h"

#include "lib/string.h"

#include "conf/conf.h"

#include <asm/types.h>

#include <linux/if.h>

#include <linux/netlink.h>

#include <linux/rtnetlink.h>

#ifndef MSG_TRUNC                        /* Hack: Several versions of glibc miss this one :( */

#define MSG_TRUNC 0x20

#endif

#ifndef IFF_LOWER_UP

#define IFF_LOWER_UP 0x10000

#endif

/*

 *        Synchronous Netlink interface

 */

struct nl_sock

{

  int fd;

  u32 seq;

  byte *rx_buffer;                        /* Receive buffer */

  struct nlmsghdr *last_hdr;                /* Recently received packet */

  uint last_size;

};

#define NL_RX_SIZE 8192

static struct nl_sock nl_scan = {.fd = -1};        /* Netlink socket for synchronous scan */

static struct nl_sock nl_req  = {.fd = -1};        /* Netlink socket for requests */

static void

nl_open_sock(struct nl_sock *nl)

{

  if (nl->fd < 0)

    {

      nl->fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);

      if (nl->fd < 0)

        die("Unable to open rtnetlink socket: %m");

      nl->seq = now;

      nl->rx_buffer = xmalloc(NL_RX_SIZE);

      nl->last_hdr = NULL;

      nl->last_size = 0;

    }

}

static void

nl_open(void)

{

  nl_open_sock(&nl_scan);

  nl_open_sock(&nl_req);

}

static void

nl_send(struct nl_sock *nl, struct nlmsghdr *nh)

{

  struct sockaddr_nl sa;

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

  sa.nl_family = AF_NETLINK;

  nh->nlmsg_pid = 0;

  nh->nlmsg_seq = ++(nl->seq);

  if (sendto(nl->fd, nh, nh->nlmsg_len, 0, (struct sockaddr *)&sa, sizeof(sa)) < 0)

    die("rtnetlink sendto: %m");

  nl->last_hdr = NULL;

}

static void

nl_request_dump(int af, int cmd)

{

  struct {

    struct nlmsghdr nh;

    struct rtgenmsg g;

  } req;

  req.nh.nlmsg_type = cmd;

  req.nh.nlmsg_len = sizeof(req);

  req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;

  req.g.rtgen_family = af;

  nl_send(&nl_scan, &req.nh);

}

static struct nlmsghdr *

nl_get_reply(struct nl_sock *nl)

{

  for(;;)

    {

      if (!nl->last_hdr)

        {

          struct iovec iov = { nl->rx_buffer, NL_RX_SIZE };

          struct sockaddr_nl sa;

          struct msghdr m = { (struct sockaddr *) &sa, sizeof(sa), &iov, 1, NULL, 0, 0 };

          int x = recvmsg(nl->fd, &m, 0);

          if (x < 0)

            die("nl_get_reply: %m");

          if (sa.nl_pid)                /* It isn't from the kernel */

            {

              DBG("Non-kernel packet\n");

              continue;

            }

          nl->last_size = x;

          nl->last_hdr = (void *) nl->rx_buffer;

          if (m.msg_flags & MSG_TRUNC)

            bug("nl_get_reply: got truncated reply which should be impossible");

        }

      if (NLMSG_OK(nl->last_hdr, nl->last_size))

        {

          struct nlmsghdr *h = nl->last_hdr;

          nl->last_hdr = NLMSG_NEXT(h, nl->last_size);

          if (h->nlmsg_seq != nl->seq)

            {

              log(L_WARN "nl_get_reply: Ignoring out of sequence netlink packet (%x != %x)",

                  h->nlmsg_seq, nl->seq);

              continue;

            }

          return h;

        }

      if (nl->last_size)

        log(L_WARN "nl_get_reply: Found packet remnant of size %d", nl->last_size);

      nl->last_hdr = NULL;

    }

}

static struct tbf rl_netlink_err = TBF_DEFAULT_LOG_LIMITS;

static int

nl_error(struct nlmsghdr *h)

{

  struct nlmsgerr *e;

  int ec;

  if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr)))

    {

      log(L_WARN "Netlink: Truncated error message received");

      return ENOBUFS;

    }

  e = (struct nlmsgerr *) NLMSG_DATA(h);

  ec = -e->error;

  if (ec)

    log_rl(&rl_netlink_err, L_WARN "Netlink: %s", strerror(ec));

  return ec;

}

static struct nlmsghdr *

nl_get_scan(void)

{

  struct nlmsghdr *h = nl_get_reply(&nl_scan);

  if (h->nlmsg_type == NLMSG_DONE)

    return NULL;

  if (h->nlmsg_type == NLMSG_ERROR)

    {

      nl_error(h);

      return NULL;

    }

  return h;

}

static int

nl_exchange(struct nlmsghdr *pkt)

{

  struct nlmsghdr *h;

  nl_send(&nl_req, pkt);

  for(;;)

    {

      h = nl_get_reply(&nl_req);

      if (h->nlmsg_type == NLMSG_ERROR)

        break;

      log(L_WARN "nl_exchange: Unexpected reply received");

    }

  return nl_error(h) ? -1 : 0;

}

/*

 *        Netlink attributes

 */

static int nl_attr_len;

static void *

nl_checkin(struct nlmsghdr *h, int lsize)

{

  nl_attr_len = h->nlmsg_len - NLMSG_LENGTH(lsize);

  if (nl_attr_len < 0)

    {

      log(L_ERR "nl_checkin: underrun by %d bytes", -nl_attr_len);

      return NULL;

    }

  return NLMSG_DATA(h);

}

static int

nl_parse_attrs(struct rtattr *a, struct rtattr **k, int ksize)

{

  int max = ksize / sizeof(struct rtattr *);

  bzero(k, ksize);

  while (RTA_OK(a, nl_attr_len))

    {

      if (a->rta_type < max)

        k[a->rta_type] = a;

      a = RTA_NEXT(a, nl_attr_len);

    }

  if (nl_attr_len)

    {

      log(L_ERR "nl_parse_attrs: remnant of size %d", nl_attr_len);

      return 0;

    }

  else

    return 1;

}

struct rtattr *

nl_add_attr(struct nlmsghdr *h, uint bufsize, uint code, const void *data, uint dlen)

{

  uint pos = NLMSG_ALIGN(h->nlmsg_len);

  uint len = RTA_LENGTH(dlen);

  if (pos + len > bufsize)

    bug("nl_add_attr: packet buffer overflow");

  struct rtattr *a = (struct rtattr *)((char *)h + pos);

  a->rta_type = code;

  a->rta_len = len;

  h->nlmsg_len = pos + len;

  if (dlen > 0)

    memcpy(RTA_DATA(a), data, dlen);

  return a;

}

static inline void

nl_add_attr_u32(struct nlmsghdr *h, unsigned bufsize, int code, u32 data)

{

  nl_add_attr(h, bufsize, code, &data, 4);

}

static inline void

nl_add_attr_ipa(struct nlmsghdr *h, unsigned bufsize, int code, ip_addr ipa)

{

  ipa_hton(ipa);

  nl_add_attr(h, bufsize, code, &ipa, sizeof(ipa));

}

static inline struct rtattr *

nl_open_attr(struct nlmsghdr *h, uint bufsize, uint code)

{

  return nl_add_attr(h, bufsize, code, NULL, 0);

}

static inline void

nl_close_attr(struct nlmsghdr *h, struct rtattr *a)

{

  a->rta_len = (void *)h + NLMSG_ALIGN(h->nlmsg_len) - (void *)a;

}

static inline struct rtnexthop *

nl_open_nexthop(struct nlmsghdr *h, uint bufsize)

{

  uint pos = NLMSG_ALIGN(h->nlmsg_len);

  uint len = RTNH_LENGTH(0);

  if (pos + len > bufsize)

    bug("nl_open_nexthop: packet buffer overflow");

  h->nlmsg_len = pos + len;

  return (void *)h + pos;

}

static inline void

nl_close_nexthop(struct nlmsghdr *h, struct rtnexthop *nh)

{

  nh->rtnh_len = (void *)h + NLMSG_ALIGN(h->nlmsg_len) - (void *)nh;

}

static void

nl_add_multipath(struct nlmsghdr *h, unsigned bufsize, struct mpnh *nh)

{

  struct rtattr *a = nl_open_attr(h, bufsize, RTA_MULTIPATH);

  for (; nh; nh = nh->next)

  {

    struct rtnexthop *rtnh = nl_open_nexthop(h, bufsize);

    rtnh->rtnh_flags = 0;

    rtnh->rtnh_hops = nh->weight;

    rtnh->rtnh_ifindex = nh->iface->index;

    nl_add_attr_ipa(h, bufsize, RTA_GATEWAY, nh->gw);

    nl_close_nexthop(h, rtnh);

  }

  nl_close_attr(h, a);

}

static struct mpnh *

nl_parse_multipath(struct krt_proto *p, struct rtattr *ra)

{

  /* Temporary buffer for multicast nexthops */

  static struct mpnh *nh_buffer;

  static int nh_buf_size;        /* in number of structures */

  static int nh_buf_used;

  struct rtattr *a[RTA_CACHEINFO+1];

  struct rtnexthop *nh = RTA_DATA(ra);

  struct mpnh *rv, *first, **last;

  int len = RTA_PAYLOAD(ra);

  first = NULL;

  last = &first;

  nh_buf_used = 0;

  while (len)

    {

      /* Use RTNH_OK(nh,len) ?? */

      if ((len < sizeof(*nh)) || (len < nh->rtnh_len))

        return NULL;

      if (nh_buf_used == nh_buf_size)

      {

        nh_buf_size = nh_buf_size ? (nh_buf_size * 2) : 4;

        nh_buffer = xrealloc(nh_buffer, nh_buf_size * sizeof(struct mpnh));

      }

      *last = rv = nh_buffer + nh_buf_used++;

      rv->next = NULL;

      last = &(rv->next);

      rv->weight = nh->rtnh_hops;

      rv->iface = if_find_by_index(nh->rtnh_ifindex);

      if (!rv->iface)

        return NULL;

      /* Nonexistent RTNH_PAYLOAD ?? */

      nl_attr_len = nh->rtnh_len - RTNH_LENGTH(0);

      nl_parse_attrs(RTNH_DATA(nh), a, sizeof(a));

      if (a[RTA_GATEWAY])

        {

          if (RTA_PAYLOAD(a[RTA_GATEWAY]) != sizeof(ip_addr))

            return NULL;

          memcpy(&rv->gw, RTA_DATA(a[RTA_GATEWAY]), sizeof(ip_addr));

          ipa_ntoh(rv->gw);

          neighbor *ng = neigh_find2(&p->p, &rv->gw, rv->iface,

                                     (nh->rtnh_flags & RTNH_F_ONLINK) ? NEF_ONLINK : 0);

          if (!ng || (ng->scope == SCOPE_HOST))

            return NULL;

        }

      else

        return NULL;

      len -= NLMSG_ALIGN(nh->rtnh_len);

      nh = RTNH_NEXT(nh);

    }

  return first;

}

static void

nl_add_metrics(struct nlmsghdr *h, uint bufsize, u32 *metrics, int max)

{

  struct rtattr *a = nl_open_attr(h, bufsize, RTA_METRICS);

  int t;

  for (t = 1; t < max; t++)

    if (metrics[0] & (1 << t))

      nl_add_attr_u32(h, bufsize, t, metrics[t]);

  nl_close_attr(h, a);

}

static int

nl_parse_metrics(struct rtattr *hdr, u32 *metrics, int max)

{

  struct rtattr *a = RTA_DATA(hdr);

  int len = RTA_PAYLOAD(hdr);

  metrics[0] = 0;

  for (; RTA_OK(a, len); a = RTA_NEXT(a, len))

  {

    if (a->rta_type == RTA_UNSPEC)

      continue;

    if (a->rta_type >= max)

      continue;

    if (RTA_PAYLOAD(a) != 4)

      return -1;

    metrics[0] |= 1 << a->rta_type;

    metrics[a->rta_type] = *(u32 *)RTA_DATA(a);

  }

  if (len > 0)

    return -1;

  return 0;

}

/*

 *        Scanning of interfaces

 */

static void

nl_parse_link(struct nlmsghdr *h, int scan)

{

  struct ifinfomsg *i;

  struct rtattr *a[IFLA_WIRELESS+1];

  int new = h->nlmsg_type == RTM_NEWLINK;

  struct iface f = {};

  struct iface *ifi;

  char *name;

  u32 mtu;

  uint fl;

  if (!(i = nl_checkin(h, sizeof(*i))) || !nl_parse_attrs(IFLA_RTA(i), a, sizeof(a)))

    return;

  if (!a[IFLA_IFNAME] || RTA_PAYLOAD(a[IFLA_IFNAME]) < 2 ||

      !a[IFLA_MTU] || RTA_PAYLOAD(a[IFLA_MTU]) != 4)

    {

      if (scan || !a[IFLA_WIRELESS])

        log(L_ERR "nl_parse_link: Malformed message received");

      return;

    }

  name = RTA_DATA(a[IFLA_IFNAME]);

  memcpy(&mtu, RTA_DATA(a[IFLA_MTU]), sizeof(u32));

  ifi = if_find_by_index(i->ifi_index);

  if (!new)

    {

      DBG("KIF: IF%d(%s) goes down\n", i->ifi_index, name);

      if (!ifi)

        return;

      if_delete(ifi);

    }

  else

    {

      DBG("KIF: IF%d(%s) goes up (mtu=%d,flg=%x)\n", i->ifi_index, name, mtu, i->ifi_flags);

      if (ifi && strncmp(ifi->name, name, sizeof(ifi->name)-1))

        if_delete(ifi);

      strncpy(f.name, name, sizeof(f.name)-1);

      f.index = i->ifi_index;

      f.mtu = mtu;

      fl = i->ifi_flags;

      if (fl & IFF_UP)

        f.flags |= IF_ADMIN_UP;

      if (fl & IFF_LOWER_UP)

        f.flags |= IF_LINK_UP;

      if (fl & IFF_LOOPBACK)                /* Loopback */

        f.flags |= IF_MULTIACCESS | IF_LOOPBACK | IF_IGNORE;

      else if (fl & IFF_POINTOPOINT)        /* PtP */

        f.flags |= IF_MULTICAST;

      else if (fl & IFF_BROADCAST)        /* Broadcast */

        f.flags |= IF_MULTIACCESS | IF_BROADCAST | IF_MULTICAST;

      else

        f.flags |= IF_MULTIACCESS;        /* NBMA */

      if (fl & IFF_MULTICAST)

        f.flags |= IF_MULTICAST;

      ifi = if_update(&f);

      if (!scan)

        if_end_partial_update(ifi);

    }

}

static void

nl_parse_addr(struct nlmsghdr *h, int scan)

{

  struct ifaddrmsg *i;

  struct rtattr *a[IFA_ANYCAST+1];

  int new = h->nlmsg_type == RTM_NEWADDR;

  struct ifa ifa;

  struct iface *ifi;

  int scope;

  if (!(i = nl_checkin(h, sizeof(*i))) || !nl_parse_attrs(IFA_RTA(i), a, sizeof(a)))

    return;

  if (i->ifa_family != BIRD_AF)

    return;

  if (!a[IFA_ADDRESS] || RTA_PAYLOAD(a[IFA_ADDRESS]) != sizeof(ip_addr)

#ifdef IPV6

      || a[IFA_LOCAL] && RTA_PAYLOAD(a[IFA_LOCAL]) != sizeof(ip_addr)

#else

      || !a[IFA_LOCAL] || RTA_PAYLOAD(a[IFA_LOCAL]) != sizeof(ip_addr)

      || (a[IFA_BROADCAST] && RTA_PAYLOAD(a[IFA_BROADCAST]) != sizeof(ip_addr))

#endif

      )

    {

      log(L_ERR "nl_parse_addr: Malformed message received");

      return;

    }

  ifi = if_find_by_index(i->ifa_index);

  if (!ifi)

    {

      log(L_ERR "KIF: Received address message for unknown interface %d", i->ifa_index);

      return;

    }

  bzero(&ifa, sizeof(ifa));

  ifa.iface = ifi;

  if (i->ifa_flags & IFA_F_SECONDARY)

    ifa.flags |= IA_SECONDARY;

  /* IFA_LOCAL can be unset for IPv6 interfaces */

  memcpy(&ifa.ip, RTA_DATA(a[IFA_LOCAL] ? : a[IFA_ADDRESS]), sizeof(ifa.ip));

  ipa_ntoh(ifa.ip);

  ifa.pxlen = i->ifa_prefixlen;

  if (i->ifa_prefixlen > BITS_PER_IP_ADDRESS)

    {

      log(L_ERR "KIF: Invalid prefix length for interface %s: %d", ifi->name, i->ifa_prefixlen);

      new = 0;

    }

  if (i->ifa_prefixlen == BITS_PER_IP_ADDRESS)

    {

      ip_addr addr;

      memcpy(&addr, RTA_DATA(a[IFA_ADDRESS]), sizeof(addr));

      ipa_ntoh(addr);

      ifa.prefix = ifa.brd = addr;

      /* It is either a host address or a peer address */

      if (ipa_equal(ifa.ip, addr))

        ifa.flags |= IA_HOST;

      else

        {

          ifa.flags |= IA_PEER;

          ifa.opposite = addr;

        }

    }

  else

    {

      ip_addr netmask = ipa_mkmask(ifa.pxlen);

      ifa.prefix = ipa_and(ifa.ip, netmask);

      ifa.brd = ipa_or(ifa.ip, ipa_not(netmask));

      if (i->ifa_prefixlen == BITS_PER_IP_ADDRESS - 1)

        ifa.opposite = ipa_opposite_m1(ifa.ip);

#ifndef IPV6

      if (i->ifa_prefixlen == BITS_PER_IP_ADDRESS - 2)

        ifa.opposite = ipa_opposite_m2(ifa.ip);

      if ((ifi->flags & IF_BROADCAST) && a[IFA_BROADCAST])

        {

          ip_addr xbrd;

          memcpy(&xbrd, RTA_DATA(a[IFA_BROADCAST]), sizeof(xbrd));

          ipa_ntoh(xbrd);

          if (ipa_equal(xbrd, ifa.prefix) || ipa_equal(xbrd, ifa.brd))

            ifa.brd = xbrd;

          else if (ifi->flags & IF_TMP_DOWN) /* Complain only during the first scan */

            log(L_ERR "KIF: Invalid broadcast address %I for %s", xbrd, ifi->name);

        }

#endif

    }

  scope = ipa_classify(ifa.ip);

  if (scope < 0)

    {

      log(L_ERR "KIF: Invalid interface address %I for %s", ifa.ip, ifi->name);

      return;

    }

  ifa.scope = scope & IADDR_SCOPE_MASK;

  DBG("KIF: IF%d(%s): %s IPA %I, flg %x, net %I/%d, brd %I, opp %I\n",

      ifi->index, ifi->name,

      new ? "added" : "removed",

      ifa.ip, ifa.flags, ifa.prefix, ifa.pxlen, ifa.brd, ifa.opposite);

  if (new)

    ifa_update(&ifa);

  else

    ifa_delete(&ifa);

  if (!scan)

    if_end_partial_update(ifi);

}

void

kif_do_scan(struct kif_proto *p UNUSED)

{

  struct nlmsghdr *h;

  if_start_update();

  nl_request_dump(AF_UNSPEC, RTM_GETLINK);

  while (h = nl_get_scan())

    if (h->nlmsg_type == RTM_NEWLINK || h->nlmsg_type == RTM_DELLINK)

      nl_parse_link(h, 1);

    else

      log(L_DEBUG "nl_scan_ifaces: Unknown packet received (type=%d)", h->nlmsg_type);

  nl_request_dump(BIRD_AF, RTM_GETADDR);

  while (h = nl_get_scan())

    if (h->nlmsg_type == RTM_NEWADDR || h->nlmsg_type == RTM_DELADDR)

      nl_parse_addr(h, 1);

    else

      log(L_DEBUG "nl_scan_ifaces: Unknown packet received (type=%d)", h->nlmsg_type);

  if_end_update();

}

/*

 *        Routes

 */

static struct krt_proto *nl_table_map[NL_NUM_TABLES];

int

krt_capable(rte *e)

{

  rta *a = e->attrs;

  if (a->cast != RTC_UNICAST)

    return 0;

  switch (a->dest)

    {

    case RTD_ROUTER:

    case RTD_DEVICE:

      if (a->iface == NULL)

        return 0;

    case RTD_BLACKHOLE:

    case RTD_UNREACHABLE:

    case RTD_PROHIBIT:

    case RTD_MULTIPATH:

      break;

    default:

      return 0;

    }

  return 1;

}

static inline int

nh_bufsize(struct mpnh *nh)

{

  int rv = 0;

  for (; nh != NULL; nh = nh->next)

    rv += RTNH_LENGTH(RTA_LENGTH(sizeof(ip_addr)));

  return rv;

}

static int

nl_send_route(struct krt_proto *p, rte *e, struct ea_list *eattrs, int new)

{

  eattr *ea;

  net *net = e->net;

  rta *a = e->attrs;

  struct {

    struct nlmsghdr h;

    struct rtmsg r;

    char buf[128 + KRT_METRICS_MAX*8 + nh_bufsize(a->nexthops)];

  } r;

  DBG("nl_send_route(%I/%d,new=%d)\n", net->n.prefix, net->n.pxlen, new);

  bzero(&r.h, sizeof(r.h));

  bzero(&r.r, sizeof(r.r));

  r.h.nlmsg_type = new ? RTM_NEWROUTE : RTM_DELROUTE;

  r.h.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));

  r.h.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | (new ? NLM_F_CREATE|NLM_F_EXCL : 0);

  r.r.rtm_family = BIRD_AF;

  r.r.rtm_dst_len = net->n.pxlen;

  r.r.rtm_tos = 0;

  r.r.rtm_table = KRT_CF->sys.table_id;

  r.r.rtm_protocol = RTPROT_BIRD;

  r.r.rtm_scope = RT_SCOPE_UNIVERSE;

  nl_add_attr_ipa(&r.h, sizeof(r), RTA_DST, net->n.prefix);

  if (ea = ea_find(eattrs, EA_KRT_METRIC))

    nl_add_attr_u32(&r.h, sizeof(r), RTA_PRIORITY, ea->u.data);

  if (ea = ea_find(eattrs, EA_KRT_PREFSRC))

    nl_add_attr_ipa(&r.h, sizeof(r), RTA_PREFSRC, *(ip_addr *)ea->u.ptr->data);

  if (ea = ea_find(eattrs, EA_KRT_REALM))

    nl_add_attr_u32(&r.h, sizeof(r), RTA_FLOW, ea->u.data);

  u32 metrics[KRT_METRICS_MAX];

  metrics[0] = 0;

  struct ea_walk_state ews = { .eattrs = eattrs };

  while (ea = ea_walk(&ews, EA_KRT_METRICS, KRT_METRICS_MAX))

  {

    int id = ea->id - EA_KRT_METRICS;

    metrics[0] |= 1 << id;

    metrics[id] = ea->u.data;

  }

  if (metrics[0])

    nl_add_metrics(&r.h, sizeof(r), metrics, KRT_METRICS_MAX);

  /* a->iface != NULL checked in krt_capable() for router and device routes */

  switch (a->dest)

    {

    case RTD_ROUTER:

      r.r.rtm_type = RTN_UNICAST;

      nl_add_attr_u32(&r.h, sizeof(r), RTA_OIF, a->iface->index);

      nl_add_attr_ipa(&r.h, sizeof(r), RTA_GATEWAY, a->gw);

      break;

    case RTD_DEVICE:

      r.r.rtm_type = RTN_UNICAST;

      nl_add_attr_u32(&r.h, sizeof(r), RTA_OIF, a->iface->index);

      break;

    case RTD_BLACKHOLE:

      r.r.rtm_type = RTN_BLACKHOLE;

      break;

    case RTD_UNREACHABLE:

      r.r.rtm_type = RTN_UNREACHABLE;

      break;

    case RTD_PROHIBIT:

      r.r.rtm_type = RTN_PROHIBIT;

      break;

    case RTD_MULTIPATH:

      r.r.rtm_type = RTN_UNICAST;

      nl_add_multipath(&r.h, sizeof(r), a->nexthops);

      break;

    default:

      bug("krt_capable inconsistent with nl_send_route");

    }

  return nl_exchange(&r.h);

}

void

krt_replace_rte(struct krt_proto *p, net *n, rte *new, rte *old, struct ea_list *eattrs)

{

  int err = 0;

  /*

   * NULL for eattr of the old route is a little hack, but we don't

   * get proper eattrs for old in rt_notify() anyway. NULL means no

   * extended route attributes and therefore matches if the kernel

   * route has any of them.

   */

  if (old)

    nl_send_route(p, old, NULL, 0);

  if (new)

    err = nl_send_route(p, new, eattrs, 1);

  if (err < 0)

    n->n.flags |= KRF_SYNC_ERROR;

  else

    n->n.flags &= ~KRF_SYNC_ERROR;

}

#define SKIP(ARG...) do { DBG("KRT: Ignoring route - " ARG); return; } while(0)

static void

nl_parse_route(struct nlmsghdr *h, int scan)

{

  struct krt_proto *p;

  struct rtmsg *i;

  struct rtattr *a[RTA_CACHEINFO+1];

  int new = h->nlmsg_type == RTM_NEWROUTE;

  ip_addr dst = IPA_NONE;

  u32 oif = ~0;

  int src;

  if (!(i = nl_checkin(h, sizeof(*i))) || !nl_parse_attrs(RTM_RTA(i), a, sizeof(a)))

    return;

  if (i->rtm_family != BIRD_AF)

    return;

  if ((a[RTA_DST] && RTA_PAYLOAD(a[RTA_DST]) != sizeof(ip_addr)) ||

#ifdef IPV6

      (a[RTA_IIF] && RTA_PAYLOAD(a[RTA_IIF]) != 4) ||

#endif

      (a[RTA_OIF] && RTA_PAYLOAD(a[RTA_OIF]) != 4) ||

      (a[RTA_GATEWAY] && RTA_PAYLOAD(a[RTA_GATEWAY]) != sizeof(ip_addr)) ||

      (a[RTA_PRIORITY] && RTA_PAYLOAD(a[RTA_PRIORITY]) != 4) ||

      (a[RTA_PREFSRC] && RTA_PAYLOAD(a[RTA_PREFSRC]) != sizeof(ip_addr)) ||

      (a[RTA_FLOW] && RTA_PAYLOAD(a[RTA_FLOW]) != 4))

    {

      log(L_ERR "KRT: Malformed message received");

      return;

    }

  if (a[RTA_DST])

    {

      memcpy(&dst, RTA_DATA(a[RTA_DST]), sizeof(dst));

      ipa_ntoh(dst);

    }

  if (a[RTA_OIF])

    memcpy(&oif, RTA_DATA(a[RTA_OIF]), sizeof(oif));

  p = nl_table_map[i->rtm_table];        /* Do we know this table? */

  DBG("KRT: Got %I/%d, type=%d, oif=%d, table=%d, prid=%d, proto=%s\n", dst, i->rtm_dst_len, i->rtm_type, oif, i->rtm_table, i->rtm_protocol, p ? p->p.name : "(none)");

  if (!p)

    SKIP("unknown table %d\n", i->rtm_table);

#ifdef IPV6

  if (a[RTA_IIF])

    SKIP("IIF set\n");

#else

  if (i->rtm_tos != 0)                        /* We don't support TOS */

    SKIP("TOS %02x\n", i->rtm_tos);

#endif

  if (scan && !new)

    SKIP("RTM_DELROUTE in scan\n");

  int c = ipa_classify_net(dst);

  if ((c < 0) || !(c & IADDR_HOST) || ((c & IADDR_SCOPE_MASK) <= SCOPE_LINK))

    SKIP("strange class/scope\n");

  // ignore rtm_scope, it is not a real scope

  // if (i->rtm_scope != RT_SCOPE_UNIVERSE)

  //   SKIP("scope %u\n", i->rtm_scope);

  switch (i->rtm_protocol)

    {

    case RTPROT_UNSPEC:

      SKIP("proto unspec\n");

    case RTPROT_REDIRECT:

      src = KRT_SRC_REDIRECT;

      break;

    case RTPROT_KERNEL:

      src = KRT_SRC_KERNEL;

      return;

    case RTPROT_BIRD:

      if (!scan)

        SKIP("echo\n");

      src = KRT_SRC_BIRD;

      break;

    case RTPROT_BOOT:

    default:

      src = KRT_SRC_ALIEN;

    }

  net *net = net_get(p->p.table, dst, i->rtm_dst_len);

  rta ra = {

    .src= p->p.main_source,

    .source = RTS_INHERIT,

    .scope = SCOPE_UNIVERSE,

    .cast = RTC_UNICAST

  };

  switch (i->rtm_type)

    {

    case RTN_UNICAST:

      if (a[RTA_MULTIPATH])

        {

          ra.dest = RTD_MULTIPATH;

          ra.nexthops = nl_parse_multipath(p, a[RTA_MULTIPATH]);

          if (!ra.nexthops)

            {

              log(L_ERR "KRT: Received strange multipath route %I/%d",

                  net->n.prefix, net->n.pxlen);

              return;

            }

          break;

        }

      ra.iface = if_find_by_index(oif);

      if (!ra.iface)

        {

          log(L_ERR "KRT: Received route %I/%d with unknown ifindex %u",

              net->n.prefix, net->n.pxlen, oif);

          return;

        }

      if (a[RTA_GATEWAY])

        {

          neighbor *ng;

          ra.dest = RTD_ROUTER;

          memcpy(&ra.gw, RTA_DATA(a[RTA_GATEWAY]), sizeof(ra.gw));

          ipa_ntoh(ra.gw);

#ifdef IPV6

          /* Silently skip strange 6to4 routes */

          if (ipa_in_net(ra.gw, IPA_NONE, 96))

            return;

#endif

          ng = neigh_find2(&p->p, &ra.gw, ra.iface,

                           (i->rtm_flags & RTNH_F_ONLINK) ? NEF_ONLINK : 0);

          if (!ng || (ng->scope == SCOPE_HOST))

            {

              log(L_ERR "KRT: Received route %I/%d with strange next-hop %I",

                  net->n.prefix, net->n.pxlen, ra.gw);

              return;

            }

        }

      else

        {

          ra.dest = RTD_DEVICE;

        }

      break;

    case RTN_BLACKHOLE:

      ra.dest = RTD_BLACKHOLE;

      break;

    case RTN_UNREACHABLE:

      ra.dest = RTD_UNREACHABLE;

      break;

    case RTN_PROHIBIT:

      ra.dest = RTD_PROHIBIT;

      break;

    /* FIXME: What about RTN_THROW? */

    default:

      SKIP("type %d\n", i->rtm_type);

      return;

    }

  rte *e = rte_get_temp(&ra);

  e->net = net;

  e->u.krt.src = src;

  e->u.krt.proto = i->rtm_protocol;

  e->u.krt.type = i->rtm_type;

  if (a[RTA_PRIORITY])

    memcpy(&e->u.krt.metric, RTA_DATA(a[RTA_PRIORITY]), sizeof(e->u.krt.metric));

  else

    e->u.krt.metric = 0;

  if (a[RTA_PREFSRC])

    {

      ip_addr ps;

      memcpy(&ps, RTA_DATA(a[RTA_PREFSRC]), sizeof(ps));

      ipa_ntoh(ps);

      ea_list *ea = alloca(sizeof(ea_list) + sizeof(eattr));

      ea->next = ra.eattrs;

      ra.eattrs = ea;

      ea->flags = EALF_SORTED;

      ea->count = 1;

      ea->attrs[0].id = EA_KRT_PREFSRC;

      ea->attrs[0].flags = 0;

      ea->attrs[0].type = EAF_TYPE_IP_ADDRESS;

      ea->attrs[0].u.ptr = alloca(sizeof(struct adata) + sizeof(ps));

      ea->attrs[0].u.ptr->length = sizeof(ps);

      memcpy(ea->attrs[0].u.ptr->data, &ps, sizeof(ps));

    }

  if (a[RTA_FLOW])

    {

      ea_list *ea = alloca(sizeof(ea_list) + sizeof(eattr));

      ea->next = ra.eattrs;

      ra.eattrs = ea;

      ea->flags = EALF_SORTED;

      ea->count = 1;

      ea->attrs[0].id = EA_KRT_REALM;

      ea->attrs[0].flags = 0;

      ea->attrs[0].type = EAF_TYPE_INT;

      memcpy(&ea->attrs[0].u.data, RTA_DATA(a[RTA_FLOW]), 4);

    }

  if (a[RTA_METRICS])

    {

      u32 metrics[KRT_METRICS_MAX];

      ea_list *ea = alloca(sizeof(ea_list) + KRT_METRICS_MAX * sizeof(eattr));

      int t, n = 0;

      if (nl_parse_metrics(a[RTA_METRICS], metrics, ARRAY_SIZE(metrics)) < 0)

        {

          log(L_ERR "KRT: Received route %I/%d with strange RTA_METRICS attribute",

              net->n.prefix, net->n.pxlen);

          return;

        }

      for (t = 1; t < KRT_METRICS_MAX; t++)

        if (metrics[0] & (1 << t))

          {

            ea->attrs[n].id = EA_CODE(EAP_KRT, KRT_METRICS_OFFSET + t);

            ea->attrs[n].flags = 0;

            ea->attrs[n].type = EAF_TYPE_INT; /* FIXME: Some are EAF_TYPE_BITFIELD */

            ea->attrs[n].u.data = metrics[t];

            n++;

          }

      if (n > 0)

        {

          ea->next = ra.eattrs;

          ea->flags = EALF_SORTED;

          ea->count = n;

          ra.eattrs = ea;

        }

    }

  if (scan)

    krt_got_route(p, e);

  else

    krt_got_route_async(p, e, new);

}

void

krt_do_scan(struct krt_proto *p UNUSED)        /* CONFIG_ALL_TABLES_AT_ONCE => p is NULL */

{

  struct nlmsghdr *h;

  nl_request_dump(BIRD_AF, RTM_GETROUTE);

  while (h = nl_get_scan())

    if (h->nlmsg_type == RTM_NEWROUTE || h->nlmsg_type == RTM_DELROUTE)

      nl_parse_route(h, 1);

    else

      log(L_DEBUG "nl_scan_fire: Unknown packet received (type=%d)", h->nlmsg_type);

}

/*

 *        Asynchronous Netlink interface

 */

static sock *nl_async_sk;                /* BIRD socket for asynchronous notifications */

static byte *nl_async_rx_buffer;        /* Receive buffer */

static void

nl_async_msg(struct nlmsghdr *h)

{

  switch (h->nlmsg_type)

    {

    case RTM_NEWROUTE:

    case RTM_DELROUTE:

      DBG("KRT: Received async route notification (%d)\n", h->nlmsg_type);

      nl_parse_route(h, 0);

      break;

    case RTM_NEWLINK:

    case RTM_DELLINK:

      DBG("KRT: Received async link notification (%d)\n", h->nlmsg_type);

      nl_parse_link(h, 0);

      break;

    case RTM_NEWADDR:

    case RTM_DELADDR:

      DBG("KRT: Received async address notification (%d)\n", h->nlmsg_type);

      nl_parse_addr(h, 0);

      break;

    default:

      DBG("KRT: Received unknown async notification (%d)\n", h->nlmsg_type);

    }

}

static int

nl_async_hook(sock *sk, int size UNUSED)

{

  struct iovec iov = { nl_async_rx_buffer, NL_RX_SIZE };

  struct sockaddr_nl sa;

  struct msghdr m = { (struct sockaddr *) &sa, sizeof(sa), &iov, 1, NULL, 0, 0 };

  struct nlmsghdr *h;

  int x;

  uint len;

  x = recvmsg(sk->fd, &m, 0);

  if (x < 0)

    {

      if (errno == ENOBUFS)

        {

          /*

           *  Netlink reports some packets have been thrown away.

           *  One day we might react to it by asking for route table

           *  scan in near future.

           */

          return 1;        /* More data are likely to be ready */

        }

      else if (errno != EWOULDBLOCK)

        log(L_ERR "Netlink recvmsg: %m");

      return 0;

    }

  if (sa.nl_pid)                /* It isn't from the kernel */

    {

      DBG("Non-kernel packet\n");

      return 1;

    }

  h = (void *) nl_async_rx_buffer;

  len = x;

  if (m.msg_flags & MSG_TRUNC)

    {

      log(L_WARN "Netlink got truncated asynchronous message");

      return 1;

    }

  while (NLMSG_OK(h, len))

    {

      nl_async_msg(h);

      h = NLMSG_NEXT(h, len);

    }

  if (len)

    log(L_WARN "nl_async_hook: Found packet remnant of size %d", len);

  return 1;

}

static void

nl_open_async(void)

{

  sock *sk;

  struct sockaddr_nl sa;

  int fd;

  if (nl_async_sk)

    return;

  DBG("KRT: Opening async netlink socket\n");

  fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);

  if (fd < 0)

    {

      log(L_ERR "Unable to open asynchronous rtnetlink socket: %m");

      return;

    }

  bzero(&sa, sizeof(sa));

  sa.nl_family = AF_NETLINK;

#ifdef IPV6

  sa.nl_groups = RTMGRP_LINK | RTMGRP_IPV6_IFADDR | RTMGRP_IPV6_ROUTE;

#else

  sa.nl_groups = RTMGRP_LINK | RTMGRP_IPV4_IFADDR | RTMGRP_IPV4_ROUTE;

#endif

  if (bind(fd, (struct sockaddr *) &sa, sizeof(sa)) < 0)

    {

      log(L_ERR "Unable to bind asynchronous rtnetlink socket: %m");

      close(fd);

      return;

    }

  nl_async_rx_buffer = xmalloc(NL_RX_SIZE);

  sk = nl_async_sk = sk_new(krt_pool);

  sk->type = SK_MAGIC;

  sk->rx_hook = nl_async_hook;

  sk->fd = fd;

  if (sk_open(sk) < 0)

    bug("Netlink: sk_open failed");

}

/*

 *        Interface to the UNIX krt module

 */

static u8 nl_cf_table[(NL_NUM_TABLES+7) / 8];

void

krt_sys_start(struct krt_proto *p)

{

  nl_table_map[KRT_CF->sys.table_id] = p;

  nl_open();

  nl_open_async();

}

void

krt_sys_shutdown(struct krt_proto *p UNUSED)

{

  nl_table_map[KRT_CF->sys.table_id] = NULL;

}

int

krt_sys_reconfigure(struct krt_proto *p UNUSED, struct krt_config *n, struct krt_config *o)

{

  return n->sys.table_id == o->sys.table_id;

}

void

krt_sys_preconfig(struct config *c UNUSED)

{

  bzero(&nl_cf_table, sizeof(nl_cf_table));

}

void

krt_sys_postconfig(struct krt_config *x)

{

  int id = x->sys.table_id;

  if (nl_cf_table[id/8] & (1 << (id%8)))

    cf_error("Multiple kernel syncers defined for table #%d", id);

  nl_cf_table[id/8] |= (1 << (id%8));

}

void

krt_sys_init_config(struct krt_config *cf)

{

  cf->sys.table_id = RT_TABLE_MAIN;

}

void

krt_sys_copy_config(struct krt_config *d, struct krt_config *s)

{

  d->sys.table_id = s->sys.table_id;

}

static const char *krt_metrics_names[KRT_METRICS_MAX] = {

  NULL, "lock", "mtu", "window", "rtt", "rttvar", "sstresh", "cwnd", "advmss",

  "reordering", "hoplimit", "initcwnd", "features", "rto_min", "initrwnd", "quickack"

};

static const char *krt_features_names[KRT_FEATURES_MAX] = {

  "ecn", NULL, NULL, "allfrag"

};

int

krt_sys_get_attr(eattr *a, byte *buf, int buflen UNUSED)

{

  switch (a->id)

  {

  case EA_KRT_PREFSRC:

    bsprintf(buf, "prefsrc");

    return GA_NAME;

  case EA_KRT_REALM:

    bsprintf(buf, "realm");

    return GA_NAME;

  case EA_KRT_LOCK:

    buf += bsprintf(buf, "lock:");

    ea_format_bitfield(a, buf, buflen, krt_metrics_names, 2, KRT_METRICS_MAX);

    return GA_FULL;

  case EA_KRT_FEATURES:

    buf += bsprintf(buf, "features:");

    ea_format_bitfield(a, buf, buflen, krt_features_names, 0, KRT_FEATURES_MAX);

    return GA_FULL;

  default:;

    int id = (int)EA_ID(a->id) - KRT_METRICS_OFFSET;

    if (id > 0 && id < KRT_METRICS_MAX)

    {

      bsprintf(buf, "%s", krt_metrics_names[id]);

      return GA_NAME;

    }

    return GA_UNKNOWN;

  }

}

void

kif_sys_start(struct kif_proto *p UNUSED)

{

  nl_open();

  nl_open_async();

}

void

kif_sys_shutdown(struct kif_proto *p UNUSED)

{

}