Initial BFD commit, work in progress.

1 files changed, 208 insertions, 0 deletions

diff --git a/proto/bfd/packets.c b/proto/bfd/packets.c
new file mode 100644
index 00000000..e48a5aaa
--- /dev/null
+++ b/proto/bfd/packets.c
@@ -0,0 +1,208 @@
+
+
+#define BFD_FLAG_POLL		(1 << 5)
+#define BFD_FLAG_FINAL		(1 << 4)
+#define BFD_FLAG_CPI		(1 << 3)
+#define BFD_FLAG_AP		(1 << 2)
+#define BFD_FLAG_DEMAND		(1 << 1)
+#define BFD_FLAG_MULTIPOINT	(1 << 0)
+
+
+struct bfd_ctl_packet
+{
+  u8 vdiag;			/* version and diagnostic */
+  u8 flags;			/* state and flags */
+  u8 detect_mult;
+  u8 length;
+  u32 snd_id;			/* sender ID, aka 'my discriminator' */
+  u32 rcv_id;			/* receiver ID, aka 'your discriminator' */
+  u32 des_min_tx_int;
+  u32 req_min_rx_int;
+  u32 req_min_echo_rx_int;
+};
+
+
+static inline void bfd_pack_vdiag(u8 version, u8 diag)
+{ return (version << 5) | diag; }
+
+static inline void bfd_pack_flags(u8 state, u8 flags)
+{ return (state << 6) | diag; }
+
+static inline u8 bfd_pkt_get_version(struct bfd_ctl_packet *pkt)
+{ return pkt->vdiag >> 5; }
+
+static inline u8 bfd_pkt_get_diag(struct bfd_ctl_packet *pkt)
+{ return pkt->vdiag && 0x1f; }
+
+
+static inline u8 bfd_pkt_get_state(struct bfd_ctl_packet *pkt)
+{ return pkt->flags >> 6; }
+
+static inline void bfd_pkt_set_state(struct bfd_ctl_packet *pkt, u8 val)
+{ pkt->flags = val << 6; }
+
+
+void
+bfd_send_ctl(struct bfd_proto *p, struct bfd_session *s, int final)
+{
+  sock *sk = p->skX;
+  struct bfd_ctl_packet *pkt = (struct ospf_packet *) sk->tbuf;
+
+  pkt->vdiag = bfd_pack_vdiag(1, s->loc_diag);
+  pkt->flags = bfd_pack_flags(s->loc_state, 0);
+  pkt->detect_mult = s->detect_mult;
+  pkt->length = 24;
+  pkt->snd_id = htonl(s->loc_id);
+  pkt->rcv_id = htonl(s->rem_id);
+  pkt->des_min_tx_int = htonl(s->des_min_tx_int);
+  pkt->req_min_rx_int = htonl(s->req_min_rx_int);
+  pkt->req_min_echo_rx_int = 0;
+
+  if (final)
+    pkt->flags |= BFD_FLAG_FINAL;
+  else if (s->poll_active)
+    pkt->flags |= BFD_FLAG_POLL;
+
+  // XXX
+  sk_send_to(sk, len, dst, 0);  
+}
+
+int
+bfd_ctl_rx_hook(sock *sk, int len)
+{
+  struct bfd_proto *p = sk->data;
+  struct bfd_ctl_packet *pkt =sk->rbuf;
+
+  if (len < BFD_BASE_LEN)
+    DROP("too short", len);
+
+  u8 version = bfd_pkt_get_version(pkt);
+  if (version != 1)
+    DROP("version mismatch", version);
+
+  if ((pkt->length < BFD_BASE_LEN) || (pkt->length > len))
+    DROP("length mismatch", pkt->length);
+
+  if (pkt->detect_mult == 0)
+    DROP("invalid detect mult", 0);
+
+  if (pkt->flags & BFD_FLAG_MULTIPOINT)
+    DROP("invalid flags", pkt->flags);
+
+  if (pkt->snd_id == 0)
+    DROP("invalid my discriminator", 0);
+
+  struct bfd_session *s;
+  u32 id = ntohl(pkt->rcv_id);
+
+  if (id)
+  {
+    s = bfd_find_session_by_id(p, id);
+
+    if (!s)
+      DROP("unknown session", id);
+  }
+  else
+  {
+    u8 ps = bfd_pkt_get_state(pkt);
+    if (ps > BFD_STATE_DOWN)
+      DROP("invalid init state", ps);
+      
+    s = bfd_find_session_by_ip(p, sk->faddr);
+
+    /* FIXME: better session matching and message */
+    if (!s || !s->opened)
+      return;
+  }
+
+  /* FIXME: better authentication handling and message */
+  if (pkt->flags & BFD_FLAG_AP)
+    DROP("authentication not supported", 0);
+
+
+  u32 old_rx_int = s->des_min_tx_int;
+  u32 old_tx_int = s->rem_min_rx_int;
+
+  s->rem_id = ntohl(pkt->snd_id);
+  s->rem_state = bfd_pkt_get_state(pkt);
+  s->rem_demand_mode = pkt->flags & BFD_FLAG_DEMAND;
+  s->rem_min_tx_int = ntohl(pkt->des_min_tx_int);
+  s->rem_min_rx_int = ntohl(pkt->req_min_rx_int);
+  s->rem_detect_mult = pkt->detect_mult;
+
+  bfd_session_process_ctl(s, pkt->flags, xxx);
+  return 1;
+
+ drop:
+  // log(L_WARN "%s: Bad packet from %I - %s (%u)", p->p.name, sk->faddr, err_dsc, err_val);
+  return 1;
+}
+
+sock *
+bfd_open_rx_sk(struct bfd_proto *p, int multihop)
+{
+  sock *sk = sk_new(p->p.pool);
+  sk->type = SK_UDP;
+  sk->sport = !multihop ? BFD_CONTROL_PORT : BFD_MULTI_CTL_PORT;
+  sk->data = p;
+
+  sk->rbsize = 64; // XXX
+  sk->rx_hook = bfd_rx_hook;
+  sk->err_hook = bfd_err_hook;
+  
+  sk->flags = SKF_LADDR_RX | (!multihop ? SKF_TTL_RX : 0);
+
+  if (sk_open(sk) < 0)
+    goto err;
+}
+
+static inline sock *
+bfd_open_tx_sk(struct bfd_proto *p, ip_addr local, struct iface *ifa)
+{
+  sock *sk = sk_new(p->p.pool);
+  sk->type = SK_UDP;
+  sk->saddr = local;
+  sk->data = p;
+
+  sk->tbsize = 64; // XXX
+  sk->err_hook = bfd_err_hook;
+ 
+  sk->iface = new;
+
+  sk->tos = PATT->tx_tos;
+  sk->priority = PATT->tx_priority;
+  sk->ttl = PATT->ttl_security ? 255 : 1;
+
+  if (sk_open(sk) < 0)
+    goto err;
+
+}
+
+struct bfd_socket *
+bfd_get_socket(struct bfd_proto *p, ip_addr local, struct iface *ifa)
+{
+  struct bfd_socket *sk;
+
+  WALK_LIST(sk, p->sockets)
+    if (ipa_equal(sk->sk->saddr, local) && (sk->sk->iface == ifa))
+      return sk->uc++, sk;
+
+  sk = mb_allocz(p->p.pool, sizeof(struct bfd_socket));
+  sk->sk = bfd_open_tx_sk(p, local, ifa);
+  sk->uc = 1;
+  add_tail(&p->sockets, &sk->n);
+
+  return sk;
+}
+
+void
+bfd_free_socket(struct bfd_socket *sk)
+{
+  if (!sk || --sk->uc)
+    return;
+
+  rem_node(&sk->n);
+  sk_stop(sk->sk);
+  rfree(sk->sk);
+  mb_free(sk);
+}