Internet on FIRE

/*

 *        BIRD -- OSPF

 *

 *        (c) 1999--2004 Ondrej Filip <feela@network.cz>

 *        (c) 2009--2014 Ondrej Zajicek <santiago@crfreenet.org>

 *        (c) 2009--2014 CZ.NIC z.s.p.o.

 *

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

 */

#include "ospf.h"

struct ospf_dbdes2_packet

{

  struct ospf_packet hdr;

  union ospf_auth auth;

  u16 iface_mtu;

  u8 options;

  u8 imms;                        /* I, M, MS bits */

  u32 ddseq;

  struct ospf_lsa_header lsas[];

};

struct ospf_dbdes3_packet

{

  struct ospf_packet hdr;

  u32 options;

  u16 iface_mtu;

  u8 padding;

  u8 imms;                        /* I, M, MS bits */

  u32 ddseq;

  struct ospf_lsa_header lsas[];

};

static inline uint

ospf_dbdes_hdrlen(struct ospf_proto *p)

{

  return ospf_is_v2(p) ?

    sizeof(struct ospf_dbdes2_packet) : sizeof(struct ospf_dbdes3_packet);

}

static void

ospf_dbdes_body(struct ospf_proto *p, struct ospf_packet *pkt,

                struct ospf_lsa_header **body, uint *count)

{

  uint plen = ntohs(pkt->length);

  uint hlen = ospf_dbdes_hdrlen(p);

  *body = ((void *) pkt) + hlen;

  *count = (plen - hlen) / sizeof(struct ospf_lsa_header);

}

static void

ospf_dump_dbdes(struct ospf_proto *p, struct ospf_packet *pkt)

{

  struct ospf_lsa_header *lsas;

  uint i, lsa_count;

  u32 pkt_ddseq;

  u16 pkt_iface_mtu;

  u8 pkt_imms;

  ASSERT(pkt->type == DBDES_P);

  ospf_dump_common(p, pkt);

  if (ospf_is_v2(p))

  {

    struct ospf_dbdes2_packet *ps = (void *) pkt;

    pkt_iface_mtu = ntohs(ps->iface_mtu);

    pkt_imms = ps->imms;

    pkt_ddseq = ntohl(ps->ddseq);

  }

  else /* OSPFv3 */

  {

    struct ospf_dbdes3_packet *ps = (void *) pkt;

    pkt_iface_mtu = ntohs(ps->iface_mtu);

    pkt_imms = ps->imms;

    pkt_ddseq = ntohl(ps->ddseq);

  }

  log(L_TRACE "%s:     mtu      %u", p->p.name, pkt_iface_mtu);

  log(L_TRACE "%s:     imms     %s%s%s", p->p.name,

      (pkt_imms & DBDES_I) ? "I " : "",

      (pkt_imms & DBDES_M) ? "M " : "",

      (pkt_imms & DBDES_MS) ? "MS" : "");

  log(L_TRACE "%s:     ddseq    %u", p->p.name, pkt_ddseq);

  ospf_dbdes_body(p, pkt, &lsas, &lsa_count);

  for (i = 0; i < lsa_count; i++)

    ospf_dump_lsahdr(p, lsas + i);

}

static void

ospf_prepare_dbdes(struct ospf_proto *p, struct ospf_neighbor *n)

{

  struct ospf_iface *ifa = n->ifa;

  struct ospf_packet *pkt;

  uint length;

  u16 iface_mtu = (ifa->type == OSPF_IT_VLINK) ? 0 : ifa->iface->mtu;

  /* Update DBDES buffer */

  if (n->ldd_bsize != ifa->tx_length)

  {

    mb_free(n->ldd_buffer);

    n->ldd_buffer = mb_allocz(n->pool, ifa->tx_length);

    n->ldd_bsize = ifa->tx_length;

  }

  pkt = n->ldd_buffer;

  ospf_pkt_fill_hdr(ifa, pkt, DBDES_P);

  if (ospf_is_v2(p))

  {

    struct ospf_dbdes2_packet *ps = (void *) pkt;

    ps->iface_mtu = htons(iface_mtu);

    ps->options = ifa->oa->options;

    ps->imms = 0;        /* Will be set later */

    ps->ddseq = htonl(n->dds);

    length = sizeof(struct ospf_dbdes2_packet);

  }

  else /* OSPFv3 */

  {

    struct ospf_dbdes3_packet *ps = (void *) pkt;

    ps->options = htonl(ifa->oa->options);

    ps->iface_mtu = htons(iface_mtu);

    ps->padding = 0;

    ps->imms = 0;        /* Will be set later */

    ps->ddseq = htonl(n->dds);

    length = sizeof(struct ospf_dbdes3_packet);

  }

  /* Prepare DBDES body */

  if (!(n->myimms & DBDES_I) && (n->myimms & DBDES_M))

  {

    struct ospf_lsa_header *lsas;

    struct top_hash_entry *en;

    uint i = 0, lsa_max;

    ospf_dbdes_body(p, pkt, &lsas, &lsa_max);

    en = (void *) s_get(&(n->dbsi));

    while (i < lsa_max)

    {

      if (!SNODE_VALID(en))

      {

        n->myimms &= ~DBDES_M;        /* Unset More bit */

        break;

      }

      if ((en->lsa.age < LSA_MAXAGE) &&

          lsa_flooding_allowed(en->lsa_type, en->domain, ifa))

      {

        lsa_hton_hdr(&(en->lsa), lsas + i);

        i++;

      }

      en = SNODE_NEXT(en);

    }

    s_put(&(n->dbsi), SNODE en);

    length += i * sizeof(struct ospf_lsa_header);

  }

  if (ospf_is_v2(p))

    ((struct ospf_dbdes2_packet *) pkt)->imms = n->myimms;

  else

    ((struct ospf_dbdes3_packet *) pkt)->imms = n->myimms;

  pkt->length = htons(length);

}

static void

ospf_do_send_dbdes(struct ospf_proto *p, struct ospf_neighbor *n)

{

  struct ospf_iface *ifa = n->ifa;

  OSPF_PACKET(ospf_dump_dbdes, n->ldd_buffer,

              "DBDES packet sent to nbr %R on %s", n->rid, ifa->ifname);

  sk_set_tbuf(ifa->sk, n->ldd_buffer);

  ospf_send_to(ifa, n->ip);

  sk_set_tbuf(ifa->sk, NULL);

}

/**

 * ospf_send_dbdes - transmit database description packet

 * @p: OSPF protocol instance

 * @n: neighbor

 *

 * Sending of a database description packet is described in 10.8 of RFC 2328.

 * Reception of each packet is acknowledged in the sequence number of another.

 * When I send a packet to a neighbor I keep a copy in a buffer. If the neighbor

 * does not reply, I don't create a new packet but just send the content

 * of the buffer.

 */

void

ospf_send_dbdes(struct ospf_proto *p, struct ospf_neighbor *n)

{

  /* RFC 2328 10.8 */

  ASSERT((n->state == NEIGHBOR_EXSTART) || (n->state == NEIGHBOR_EXCHANGE));

  if (n->ifa->oa->rt == NULL)

    return;

  ospf_prepare_dbdes(p, n);

  ospf_do_send_dbdes(p, n);

}

void

ospf_rxmt_dbdes(struct ospf_proto *p, struct ospf_neighbor *n)

{

  ASSERT(n->state > NEIGHBOR_EXSTART);

  if (!n->ldd_buffer)

  {

    log(L_WARN "%s: No DBDES packet for retransmit", p->p.name);

    ospf_neigh_sm(n, INM_SEQMIS);

    return;

  }

  /* Send last packet */

  ospf_do_send_dbdes(p, n);

}

static int

ospf_process_dbdes(struct ospf_proto *p, struct ospf_packet *pkt, struct ospf_neighbor *n)

{

  struct ospf_iface *ifa = n->ifa;

  struct ospf_lsa_header *lsas, lsa;

  struct top_hash_entry *en, *req;

  const char *err_dsc = NULL;

  u32 lsa_type, lsa_domain;

  uint i, lsa_count;

  ospf_dbdes_body(p, pkt, &lsas, &lsa_count);

  for (i = 0; i < lsa_count; i++)

  {

    lsa_ntoh_hdr(lsas + i, &lsa);

    lsa_get_type_domain(&lsa, ifa, &lsa_type, &lsa_domain);

    /* RFC 2328 10.6 and RFC 5340 4.2.2 */

    if (!lsa_type)

      DROP1("LSA of unknown type");

    if (!oa_is_ext(ifa->oa) && (LSA_SCOPE(lsa_type) == LSA_SCOPE_AS))

      DROP1("LSA with AS scope in stub area");

    /* Errata 3746 to RFC 2328 - rt-summary-LSAs forbidden in stub areas */

    if (!oa_is_ext(ifa->oa) && (lsa_type == LSA_T_SUM_RT))

      DROP1("rt-summary-LSA in stub area");

    /* Not explicitly mentioned in RFC 5340 4.2.2 but makes sense */

    if (LSA_SCOPE(lsa_type) == LSA_SCOPE_RES)

      DROP1("LSA with invalid scope");

    en = ospf_hash_find(p->gr, lsa_domain, lsa.id, lsa.rt, lsa_type);

    if (!en || (lsa_comp(&lsa, &(en->lsa)) == CMP_NEWER))

    {

      /* This should be splitted to ospf_lsa_lsrq_up() */

      req = ospf_hash_get(n->lsrqh, lsa_domain, lsa.id, lsa.rt, lsa_type);

      if (!SNODE_VALID(req))

        s_add_tail(&n->lsrql, SNODE req);

      if (!SNODE_VALID(n->lsrqi))

        n->lsrqi = req;

      req->lsa = lsa;

      req->lsa_body = LSA_BODY_DUMMY;

      if (!tm_active(n->lsrq_timer))

        tm_start(n->lsrq_timer, 0);

    }

  }

  return 0;

drop:

  LOG_LSA1("Bad LSA (Type: %04x, Id: %R, Rt: %R) in DBDES", lsa_type, lsa.id, lsa.rt);

  LOG_LSA2("  received from nbr %R on %s - %s", n->rid, ifa->ifname, err_dsc);

  ospf_neigh_sm(n, INM_SEQMIS);

  return -1;

}

void

ospf_receive_dbdes(struct ospf_packet *pkt, struct ospf_iface *ifa,

                   struct ospf_neighbor *n)

{

  struct ospf_proto *p = ifa->oa->po;

  const char *err_dsc = NULL;

  u32 rcv_ddseq, rcv_options;

  u16 rcv_iface_mtu;

  u8 rcv_imms;

  uint plen, err_val = 0;

  /* RFC 2328 10.6 */

  plen = ntohs(pkt->length);

  if (plen < ospf_dbdes_hdrlen(p))

  {

    LOG_PKT("Bad DBDES packet from nbr %R on %s - %s (%u)", n->rid, ifa->ifname, "too short", plen);

    return;

  }

  OSPF_PACKET(ospf_dump_dbdes, pkt, "DBDES packet received from nbr %R on %s", n->rid, ifa->ifname);

  ospf_neigh_sm(n, INM_HELLOREC);

  if (ospf_is_v2(p))

  {

    struct ospf_dbdes2_packet *ps = (void *) pkt;

    rcv_iface_mtu = ntohs(ps->iface_mtu);

    rcv_options = ps->options;

    rcv_imms = ps->imms;

    rcv_ddseq = ntohl(ps->ddseq);

  }

  else /* OSPFv3 */

  {

    struct ospf_dbdes3_packet *ps = (void *) pkt;

    rcv_options = ntohl(ps->options);

    rcv_iface_mtu = ntohs(ps->iface_mtu);

    rcv_imms = ps->imms;

    rcv_ddseq = ntohl(ps->ddseq);

  }

  switch (n->state)

  {

  case NEIGHBOR_DOWN:

  case NEIGHBOR_ATTEMPT:

  case NEIGHBOR_2WAY:

    OSPF_TRACE(D_PACKETS, "DBDES packet ignored - lesser state than ExStart");

    return;

  case NEIGHBOR_INIT:

    ospf_neigh_sm(n, INM_2WAYREC);

    if (n->state != NEIGHBOR_EXSTART)

      return;

  case NEIGHBOR_EXSTART:

    if ((ifa->type != OSPF_IT_VLINK) &&

        (rcv_iface_mtu != ifa->iface->mtu) &&

        (rcv_iface_mtu != 0) &&

        (ifa->iface->mtu != 0))

      LOG_PKT_WARN("MTU mismatch with nbr %R on %s (remote %d, local %d)",

                   n->rid, ifa->ifname, rcv_iface_mtu, ifa->iface->mtu);

    if ((rcv_imms == DBDES_IMMS) &&

        (n->rid > p->router_id) &&

        (plen == ospf_dbdes_hdrlen(p)))

    {

      /* I'm slave! */

      n->dds = rcv_ddseq;

      n->ddr = rcv_ddseq;

      n->options = rcv_options;

      n->myimms &= ~DBDES_MS;

      n->imms = rcv_imms;

      tm_stop(n->dbdes_timer);

      ospf_neigh_sm(n, INM_NEGDONE);

      ospf_send_dbdes(p, n);

      break;

    }

    if (!(rcv_imms & DBDES_I) &&

        !(rcv_imms & DBDES_MS) &&

        (n->rid < p->router_id) &&

        (n->dds == rcv_ddseq))

    {

      /* I'm master! */

      n->options = rcv_options;

      n->ddr = rcv_ddseq - 1;        /* It will be set corectly a few lines down */

      n->imms = rcv_imms;

      ospf_neigh_sm(n, INM_NEGDONE);

      /* Continue to the NEIGHBOR_EXCHANGE case */

    }

    else

    {

      DBG("%s: Nothing happend to %I (imms=%d)\n", p->name, n->ip, rcv_imms);

      break;

    }

  case NEIGHBOR_EXCHANGE:

    if ((rcv_imms == n->imms) &&

        (rcv_options == n->options) &&

        (rcv_ddseq == n->ddr))

      goto duplicate;

    if ((rcv_imms & DBDES_MS) != (n->imms & DBDES_MS))

      DROP("MS-bit mismatch", rcv_imms);

    if (rcv_imms & DBDES_I)

      DROP("I-bit mismatch", rcv_imms);

    if (rcv_options != n->options)

      DROP("options mismatch", rcv_options);

    n->ddr = rcv_ddseq;

    n->imms = rcv_imms;

    if (n->myimms & DBDES_MS)

    {

      /* MASTER */

      if (rcv_ddseq != n->dds)

        DROP("DD sequence number mismatch", rcv_ddseq);

      n->dds++;

      if (ospf_process_dbdes(p, pkt, n) < 0)

        return;

      if (!(n->myimms & DBDES_M) && !(n->imms & DBDES_M))

      {

        tm_stop(n->dbdes_timer);

        ospf_neigh_sm(n, INM_EXDONE);

        break;

      }

      ospf_send_dbdes(p, n);

      tm_start(n->dbdes_timer, n->ifa->rxmtint);

    }

    else

    {

      /* SLAVE */

      if (rcv_ddseq != (n->dds + 1))

        DROP("DD sequence number mismatch", rcv_ddseq);

      n->ddr = rcv_ddseq;

      n->dds = rcv_ddseq;

      if (ospf_process_dbdes(p, pkt, n) < 0)

        return;

      ospf_send_dbdes(p, n);

      if (!(n->myimms & DBDES_M) && !(n->imms & DBDES_M))

        ospf_neigh_sm(n, INM_EXDONE);

    }

    break;

  case NEIGHBOR_LOADING:

  case NEIGHBOR_FULL:

    if ((rcv_imms == n->imms) &&

        (rcv_options == n->options) &&

        (rcv_ddseq == n->ddr))

      goto duplicate;

    DROP("too late for DD exchange", n->state);

  default:

    bug("Undefined interface state");

  }

  return;

duplicate:

  OSPF_TRACE(D_PACKETS, "DBDES packet is duplicate");

  /* Slave should retransmit DBDES packet */

  if (!(n->myimms & DBDES_MS))

    ospf_rxmt_dbdes(p, n);

  return;

drop:

  LOG_PKT("Bad DBDES packet from nbr %R on %s - %s (%u)",

          n->rid, ifa->ifname, err_dsc, err_val);

  ospf_neigh_sm(n, INM_SEQMIS);

  return;

}