Initial BFD commit, work in progress.

1 files changed, 496 insertions, 0 deletions

diff --git a/proto/bfd/bfd.c b/proto/bfd/bfd.c
new file mode 100644
index 00000000..4c7fe1f1
--- /dev/null
+++ b/proto/bfd/bfd.c
@@ -0,0 +1,496 @@
+#include "nest/bird.h"
+#include "nest/iface.h"
+#include "nest/protocol.h"
+#include "nest/route.h"
+#include "nest/cli.h"
+#include "conf/conf.h"
+#include "lib/socket.h"
+#include "lib/resource.h"
+#include "lib/string.h"
+
+#include "bfd.h"
+
+
+#define HASH_ID_KEY	loc_id
+#define HASH_ID_NEXT	next_id
+#define HASH_ID_EQ(a,b)	((a)==(b))
+#define HASH_ID_FN(a)	(a)
+
+#define HASH_IP_KEY	addr
+#define HASH_IP_NEXT	next_ip
+#define HASH_IP_EQ(a,b)	((a)==(b))
+#define HASH_IP_FN(a)	(a == b)
+
+static u32
+bfd_get_free_id(struct bfd_proto *p)
+{
+  u32 id;
+  for (id = random_u32(); 1; id++)
+    if (id && !bfd_find_session_by_id(p, id))
+      break;
+
+  return id;
+}
+
+static void
+bfd_add_session(struct bfd_proto *p, ip_addr addr, struct bfd_session_config *opts)
+{
+  birdloop_enter(p->loop);
+
+  struct bfd_session *s = sl_alloc(p->session_slab);
+  bzero(s, sizeof(struct bfd_session));
+
+  /* Initialization of state variables - see RFC 5880 3.8.1 */
+  s->loc_state = BFD_STATE_DOWN;
+  s->rem_state = BFD_STATE_DOWN;
+  s->loc_id = bfd_get_free_id(p);
+  s->des_min_tx_int = s->des_min_tx_new = s->opts->idle_tx_int;
+  s->req_min_rx_int = s->req_min_rx_new = s->opts->min_rx_int;
+  s->detect_mult = s->opts->multiplier;
+  s->rem_min_rx_int = 1;
+
+  HASH_INSERT(p->session_hash_id, HASH_ID, s);
+  HASH_INSERT(p->session_hash_ip, HASH_IP, s);
+
+  s->tx_timer = tm2_new_set(xxx, bfd_rx_timer_hook, s, 0, 0);
+  s->hold_timer = tm2_new_set(xxx, bfd_hold_timer_hook, s, 0, 0);
+  bfd_session_update_tx_interval(s);
+
+  birdloop_leave(p->loop);
+}
+
+static void
+bfd_open_session(struct bfd_proto *p, struct bfd_session *s, ip_addr local, struct iface *ifa)
+{
+  birdloop_enter(p->loop);
+
+  s->bsock = bfd_get_socket(p, local, ifa);
+  s->local = local;
+  s->iface = ifa;
+  s->opened = 1;
+
+  bfd_session_control_tx_timer(s);
+
+  birdloop_leave(p->loop);
+}
+
+static void
+bfd_close_session(struct bfd_proto *p, struct bfd_session *s)
+{
+  birdloop_enter(p->loop);
+
+  bfd_free_socket(s->bsock);
+  s->bsock = NULL;
+  s->local = IPA_NONE;
+  s->iface = NULL;
+  s->opened = 0;
+
+  bfd_session_control_tx_timer(s);
+
+  birdloop_leave(p->loop);
+}
+
+static void
+bfd_remove_session(struct bfd_proto *p, struct bfd_session *s)
+{
+  birdloop_enter(p->loop);
+
+  bfd_free_socket(s->bsock);
+
+  rfree(s->tx_timer);
+  rfree(s->hold_timer);
+
+  HASH_REMOVE(p->session_hash_id, HASH_ID, s);
+  HASH_REMOVE(p->session_hash_ip, HASH_IP, s);
+
+  sl_free(p->session_slab, s);
+
+  birdloop_leave(p->loop);
+}
+
+struct bfd_session *
+bfd_find_session_by_id(struct bfd_proto *p, u32 id)
+{
+  return HASH_FIND(p->session_hash_id, HASH_ID, id);
+}
+
+struct bfd_session *
+bfd_find_session_by_addr(struct bfd_proto *p, ip_addr addr)
+{
+  return HASH_FIND(p->session_hash_ip, HASH_IP, addr);
+}
+
+static void
+bfd_rx_timer_hook(timer2 *t)
+{
+  struct bfd_session *s = timer->data;
+
+  s->last_tx = xxx_now;
+  bfd_send_ctl(s->bfd, s, 0);
+}
+
+static void
+bfd_hold_timer_hook(timer2 *t)
+{
+  bfd_session_timeout(timer->data);
+}
+
+static void 
+bfd_session_timeout(struct bfd_session *s)
+{
+  s->rem_state = BFD_STATE_DOWN;
+  s->rem_id = 0;
+  s->rem_min_tx_int = 0;
+  s->rem_min_rx_int = 1;
+  s->rem_demand_mode = 0;
+
+  bfd_session_update_state(s, BFD_STATE_DOWN, BFD_DIAG_TIMEOUT);
+}
+
+static void
+bfd_session_control_tx_timer(struct bfd_session *s)
+{
+  if (!s->opened)
+    goto stop;
+
+  if (s->passive && (s->rem_id == 0))
+    goto stop;
+
+  if (s->rem_demand_mode && 
+      !s->poll_active && 
+      (s->loc_state == BFD_STATE_UP) &&
+      (s->rem_state == BFD_STATE_UP))
+    goto stop;
+
+  if (s->rem_min_rx_int == 0)
+    goto stop;
+
+  /* So TX timer should run */
+  if (tm2_active(s->tx_timer))
+    return;
+
+  tm2_start(s->tx_timer, 0);
+  return;
+
+ stop:
+  tm2_stop(s->tx_timer);
+  s->last_tx = 0;
+}
+
+static void
+bfd_session_update_tx_interval(struct bfd_session *s)
+{
+  u32 tx_int = MAX(s->des_min_tx_int, s->rem_min_rx_int);
+  u32 tx_int_l = tx_int - (tx_int / 4);	 // 75 %
+  u32 tx_int_h = tx_int - (tx_int / 10); // 90 %
+
+  s->tx_timer->recurrent = tx_int_l;
+  s->tx_timer->randomize = tx_int_h - tx_int_l;
+
+  /* Do not set timer if no previous event */
+  if (!s->last_tx)
+    return;
+
+  /* Set timer relative to last tx_timer event */
+  tm2_set(s->tx_timer, s->last_tx + tx_int_l);
+}
+
+static void
+bfd_session_update_detection_time(struct bfd_session *s, int kick)
+{
+  xxx_time timeout = (xxx_time) MAX(s->req_min_rx_int, s->rem_min_tx_int) * s->rem_detect_mult;
+
+  if (kick)
+    s->last_rx = xxx_now;
+
+  if (!s->last_rx)
+    return;
+
+  tm2_set(s->hold_timer, s->last_rx + timeout);
+}
+
+void
+bfd_session_request_poll(struct bfd_session *s, u8 request)
+{
+  s->poll_scheduled |= request;
+
+  if (s->poll_active)
+    return;
+
+  s->poll_active = s->poll_scheduled;
+  s->poll_scheduled = 0;
+  bfd_send_ctl(s->bfd, s, 0);
+}
+
+void
+bfd_session_terminate_poll(struct bfd_session *s)
+{
+  u8 poll_done = s->poll_active & ~s->poll_scheduled;
+
+  if (poll_done & BFD_POLL_TX)
+    s->des_min_tx_int = s->des_min_tx_new;
+
+  if (poll_done & BFD_POLL_RX)
+    s->req_min_rx_int = s->req_min_rx_new;
+
+  s->poll_active = 0;
+
+  /* Timers are updated by caller - bfd_session_process_ctl() */
+
+  xxx_restart_poll();
+}
+
+void
+bfd_session_process_ctl(struct bfd_session *s, u8 flags, u32 old_rx_int, u32 old_tx_int)
+{
+  if (s->poll_active && (flags & BFD_FLAG_FINAL))
+    bfd_session_terminate_poll(s);
+
+  if ((s->des_min_tx_int != old_rx_int) || (s->rem_min_rx_int != old_tx_int))
+    bfd_session_update_tx_interval(s);
+
+  bfd_session_update_detection_time(s, 1);
+
+  /* Update session state */
+  int next_state = 0;
+  int diag = BFD_DIAG_NOTHING;
+
+  switch (s->loc_state)
+  {
+  case BFD_STATE_ADMIN_DOWN:
+    return;
+
+  case BFD_STATE_DOWN:
+    if (s->rem_state == BFD_STATE_DOWN)		next_state = BFD_STATE_INIT;
+    else if (s->rem_state == BFD_STATE_INIT)	next_state = BFD_STATE_UP;
+    break;
+
+  case BFD_STATE_INIT:
+    if (s->rem_state == BFD_STATE_ADMIN_DOWN)	next_state = BFD_STATE_DOWN, diag = BFD_DIAG_NEIGHBOR_DOWN;
+    else if (s->rem_state >= BFD_STATE_INIT)	next_state = BFD_STATE_UP;
+    break;
+
+  case BFD_STATE_UP:
+    if (s->rem_state <= BFD_STATE_DOWN)		next_state = BFD_STATE_DOWN, diag = BFD_DIAG_NEIGHBOR_DOWN;
+    break;
+  }
+
+  if (next_state)
+    bfd_session_update_state(s, next_state, diag);
+
+  bfd_session_control_tx_timer(s);
+
+  if (flags & BFD_FLAG_POLL)
+    bfd_send_ctl(p, s, 1);
+}
+
+
+static void
+bfd_session_set_min_tx(struct bfd_session *s, u32 val)
+{
+  /* Note that des_min_tx_int <= des_min_tx_new */
+
+  if (val == s->des_min_tx_new)
+    return;
+
+  s->des_min_tx_new = val;
+
+  /* Postpone timer update if des_min_tx_int increases and the session is up */
+  if ((s->loc_state != BFD_STATE_UP) || (val < s->des_min_tx_int))
+  {
+    s->des_min_tx_int = val;
+    bfd_session_update_tx_interval(s);
+  }
+
+  bfd_session_request_poll(s, BFD_POLL_TX);
+}
+
+static void
+bfd_session_set_min_rx(struct bfd_session *s, u32 val)
+{
+  /* Note that req_min_rx_int >= req_min_rx_new */
+
+  if (val == s->req_min_rx_new)
+    return;
+
+  s->req_min_rx_new = val; 
+
+  /* Postpone timer update if req_min_rx_int decreases and the session is up */
+  if ((s->loc_state != BFD_STATE_UP) || (val > s->req_min_rx_int))
+  {
+    s->req_min_rx_int = val;
+    bfd_session_update_detection_time(s, 0);
+  }
+
+  bfd_session_request_poll(s, BFD_POLL_RX);
+}
+
+static void
+bfd_start_neighbor(struct bfd_proto *p, struct bfd_neighbor *n)
+{
+  n->session = bfd_add_session(p, n->addr, n->opts);
+
+  if (n->opts->multihop)
+  {
+    bfd_open_session(p, n->session, n->local, NULL);
+    return;
+  }
+
+  struct neighbor *nb = neigh_find2(&p->p, &n->addr, n->iface, NEF_STICKY);
+  if (!nb)
+  {
+    log(L_ERR "%s: Invalid remote address %I%J", p->p.name, n->addr, n->iface);
+    return;
+  }
+
+  if (nb->data)
+  {
+    log(L_ERR "%s: Duplicate remote address %I", p->p.name, n->addr);
+    return;
+  }
+
+  nb->data = n->session;
+
+  if (nb->scope > 0)
+    bfd_open_session(p, n->session, nb->iface->addr->ip, nb->iface);
+  else
+    TRACE(D_EVENTS, "Waiting for %I%J to become my neighbor", n->addr, cf->iface);
+}
+
+static void
+bfd_stop_neighbor(struct bfd_proto *p, struct bfd_neighbor *n)
+{
+  if (!n->opts->multihop)
+  {
+    struct neighbor *nb = neigh_find2(&p->p, &n->addr, n->iface, 0);
+    if (nb)
+      nb->data = NULL;
+  }
+
+  bfd_remove_session(p, n->session);
+}
+
+
+static void
+bfd_neigh_notify(struct neighbor *nb)
+{
+  struct bfd_proto *p = (struct bfd_proto *) nb->proto;
+  struct bfd_session *s = nb->data;
+
+  if (!s)
+    return;
+
+  if ((nb->scope > 0) && !s->opened)
+    bfd_open_session(p, s, nb->iface->addr->ip, nb->iface);
+
+  if ((nb->scope <= 0) && s->opened)
+    bfd_close_session(p, s);
+}
+
+
+
+static struct proto *
+bfd_init(struct proto_config *c)
+{
+  struct proto *p = proto_new(c, sizeof(struct bfd_proto));
+
+  p->if_notify = bfd_if_notify;
+  p->ifa_notify = bfd_ifa_notify;
+
+  return p;
+}
+
+static int
+bfd_start(struct proto *P)
+{
+  struct bfd_proto *p = (struct bfd_proto *) P;
+  struct bfd_config *cf = (struct bfd_config *) (P->cf);
+
+  p->session_slab = sl_new(P->pool, sizeof(struct bfd_session));
+  init_list(&p->sockets);
+
+  HASH_INIT(p->session_hash_id, P->pool, 16);
+  HASH_INIT(p->session_hash_ip, P->pool, 16);
+
+  struct bfd_neighbor *n;
+  WALK_LIST(n, cf->neighbors)
+    bfd_start_neighbor(p, n);
+
+  return PS_UP;
+}
+
+
+static int
+bfd_shutdown(struct proto *P)
+{
+  struct bfd_proto *p = (struct bfd_proto *) P;
+
+  return PS_DOWN;
+}
+
+static inline int
+bfd_same_neighbor(struct bfd_neighbor *x, struct bfd_neighbor *y)
+{
+  return ipa_equal(x->addr, y->addr) && ipa_equal(x->local, y->local) &&
+    (x->iface == y->iface) && (x->opts->multihop == y->opts->multihop);
+}
+
+static void
+bfd_match_neighbor(struct bfd_proto *p, struct bfd_neighbor *on, struct bfd_config *new)
+{
+  struct bfd_neighbor *nn;
+
+  if (r->neigh)
+    r->neigh->data = NULL;
+
+  WALK_LIST(nn, new->neighbors)
+    if (bfd_same_neighbor(nn, on))
+    {
+      nn->session = on->session;
+      // XXX reconfiguration of session?
+      return;
+    }
+
+  bfd_stop_neighbor(p, on);
+}
+
+static int
+bfd_reconfigure(struct proto *P, struct proto_config *c)
+{
+  struct bfd_proto *p = (struct bfd_proto *) P;
+  struct bfd_config *old = (struct bfd_config *) (P->cf);
+  struct bfd_config *new = (struct bfd_config *) c;
+  struct bfd_neighbor *n;
+
+  WALK_LIST(n, old->neighbors)
+    bfd_match_neighbor(p, n, new);
+
+  WALK_LIST(n, new->neighbors)
+    if (!n->session)
+      bfd_start_neighbor(p, n);
+
+  return 1;
+}
+
+static void
+bfd_copy_config(struct proto_config *dest, struct proto_config *src)
+{
+  struct bfd_config *d = (struct bfd_config *) dest;
+  struct bfd_config *s = (struct bfd_config *) src;
+
+  /* We clean up patt_list, ifaces are non-sharable */
+  init_list(&d->patt_list);
+
+  /* We copy pref_list, shallow copy suffices */
+  cfg_copy_list(&d->pref_list, &s->pref_list, sizeof(struct bfd_prefix_config));
+}
+
+struct protocol proto_bfd = {
+  .name =		"BFD",
+  .template =		"bfd%d",
+  .init =		bfd_init,
+  .start =		bfd_start,
+  .shutdown =		bfd_shutdown,
+  .reconfigure =	bfd_reconfigure,
+  .copy_config =	bfd_copy_config,
+};