diff --git a/proto/babel/babel.c b/proto/babel/babel.c
index ecfd2763d737a697900d2c7df5777a0fac07bc98..23cb67744c65fbf778076873c66cf0f148e1c6e5 100644
--- a/proto/babel/babel.c
+++ b/proto/babel/babel.c
@@ -53,7 +53,7 @@ static void babel_expire_requests(struct babel_proto *p, struct babel_entry *e);
static void babel_select_route(struct babel_proto *p, struct babel_entry *e, struct babel_route *mod);
static inline void babel_announce_retraction(struct babel_proto *p, struct babel_entry *e);
static void babel_send_route_request(struct babel_proto *p, struct babel_entry *e, struct babel_neighbor *n);
-static void babel_send_seqno_request(struct babel_proto *p, struct babel_entry *e, struct babel_seqno_request *sr);
+static void babel_send_seqno_request(struct babel_proto *p, struct babel_entry *e, struct babel_seqno_request *sr, struct babel_neighbor *n);
static void babel_update_cost(struct babel_neighbor *n);
static inline void babel_kick_timer(struct babel_proto *p);
static inline void babel_iface_kick_timer(struct babel_iface *ifa);
@@ -288,9 +288,6 @@ babel_expire_routes(struct babel_proto *p)
babel_expire_routes_(p, &p->ip6_rtable);
}
-static inline int seqno_request_valid(struct babel_seqno_request *sr)
-{ return !sr->nbr || sr->nbr->ifa; }
-
/*
* Add seqno request to the table of pending requests (RFC 6216 3.2.6) and send
* it to network. Do nothing if it is already in the table.
@@ -299,50 +296,82 @@ static inline int seqno_request_valid(struct babel_seqno_request *sr)
static void
babel_add_seqno_request(struct babel_proto *p, struct babel_entry *e,
u64 router_id, u16 seqno, u8 hop_count,
- struct babel_neighbor *nbr)
+ struct babel_neighbor *target)
{
struct babel_seqno_request *sr;
+ btime now_ = current_time();
WALK_LIST(sr, e->requests)
if (sr->router_id == router_id)
{
- /* Found matching or newer */
- if (ge_mod64k(sr->seqno, seqno) && seqno_request_valid(sr))
+ /*
+ * To suppress duplicates, check if we already have a newer (higher seqno)
+ * outstanding request. If we do, suppress this request if the outstanding
+ * request is one we originated ourselves. If the outstanding request is
+ * forwarded, suppress only if this request is also one we're forwarding
+ * *and* we're within the duplicate suppression time of that request (see
+ * below).
+ */
+ if (ge_mod64k(sr->seqno, seqno) &&
+ (!sr->forwarded || (target && now_ < sr->dup_suppress_time)))
return;
- /* Found older */
rem_node(NODE sr);
- if (sr->nbr)
- rem_node(&sr->nbr_node);
+ /* Allow upgrading from forwarded to non-forwarded */
+ if (!target)
+ sr->forwarded = 0;
goto found;
}
/* No entries found */
sr = sl_allocz(p->seqno_slab);
+ sr->forwarded = !!target;
found:
sr->router_id = router_id;
sr->seqno = seqno;
- sr->hop_count = hop_count;
+ sr->hop_count = hop_count ?: BABEL_INITIAL_HOP_COUNT;
sr->count = 0;
- sr->expires = current_time() + BABEL_SEQNO_REQUEST_EXPIRY;
- if (sr->nbr = nbr)
- add_tail(&nbr->requests, &sr->nbr_node);
+ if (sr->forwarded)
+ {
+ /*
+ * We want to keep the entry around for a reasonable period of time so it
+ * can be used to trigger an update (through babel_satisfy_seqno_request()).
+ * However, duplicate suppression should only trigger for a short period of
+ * time so it suppresses duplicates from multiple sources, but not
+ * retransmissions from the same source. Hence we keep two timers.
+ */
+ sr->expires = now_ + BABEL_SEQNO_FORWARD_EXPIRY;
+ sr->dup_suppress_time = now_ + BABEL_SEQNO_DUP_SUPPRESS_TIME;
+ }
+ else
+ {
+ sr->expires = now_ + BABEL_SEQNO_REQUEST_EXPIRY;
+ }
add_tail(&e->requests, NODE sr);
+ babel_send_seqno_request(p, e, sr, target);
+}
- babel_send_seqno_request(p, e, sr);
+static void
+babel_generate_seqno_request(struct babel_proto *p, struct babel_entry *e,
+ u64 router_id, u16 seqno, struct babel_neighbor *target)
+{
+ struct babel_seqno_request req = {
+ .router_id = router_id,
+ .seqno = seqno,
+ .hop_count = BABEL_INITIAL_HOP_COUNT,
+ };
+
+ babel_send_seqno_request(p, e, &req, target);
}
static void
babel_remove_seqno_request(struct babel_proto *p UNUSED, struct babel_seqno_request *sr)
{
- if (sr->nbr)
- rem_node(&sr->nbr_node);
-
rem_node(NODE sr);
sl_free(sr);
}
@@ -372,21 +401,14 @@ babel_expire_requests(struct babel_proto *p, struct babel_entry *e)
WALK_LIST_DELSAFE(sr, srx, e->requests)
{
- /* Remove seqno requests sent to dead neighbors */
- if (!seqno_request_valid(sr))
- {
- babel_remove_seqno_request(p, sr);
- continue;
- }
-
/* Handle expired requests - resend or remove */
if (sr->expires && sr->expires <= now_)
{
- if (sr->count < BABEL_SEQNO_REQUEST_RETRY)
+ if (!sr->forwarded && sr->count < BABEL_SEQNO_REQUEST_RETRY)
{
sr->count++;
sr->expires += (BABEL_SEQNO_REQUEST_EXPIRY << sr->count);
- babel_send_seqno_request(p, e, sr);
+ babel_send_seqno_request(p, e, sr, NULL);
}
else
{
@@ -431,7 +453,6 @@ babel_get_neighbor(struct babel_iface *ifa, ip_addr addr)
nbr->cost = BABEL_INFINITY;
nbr->init_expiry = current_time() + BABEL_INITIAL_NEIGHBOR_TIMEOUT;
init_list(&nbr->routes);
- init_list(&nbr->requests);
add_tail(&ifa->neigh_list, NODE nbr);
return nbr;
@@ -452,10 +473,6 @@ babel_flush_neighbor(struct babel_proto *p, struct babel_neighbor *nbr)
babel_flush_route(p, r);
}
- struct babel_seqno_request *sr;
- WALK_LIST_FIRST2(sr, nbr_node, nbr->requests)
- babel_remove_seqno_request(p, sr);
-
nbr->ifa = NULL;
rem_node(NODE nbr);
mb_free(nbr);
@@ -903,22 +920,23 @@ babel_send_wildcard_request(struct babel_iface *ifa)
}
static void
-babel_send_seqno_request(struct babel_proto *p, struct babel_entry *e, struct babel_seqno_request *sr)
+babel_send_seqno_request(struct babel_proto *p, struct babel_entry *e,
+ struct babel_seqno_request *sr, struct babel_neighbor *n)
{
union babel_msg msg = {};
msg.type = BABEL_TLV_SEQNO_REQUEST;
- msg.seqno_request.hop_count = sr->hop_count ?: BABEL_INITIAL_HOP_COUNT;
+ msg.seqno_request.hop_count = sr->hop_count;
msg.seqno_request.seqno = sr->seqno;
msg.seqno_request.router_id = sr->router_id;
net_copy(&msg.seqno_request.net, e->n.addr);
- if (sr->nbr)
+ if (n)
{
TRACE(D_PACKETS, "Sending seqno request for %N router-id %lR seqno %d to %I on %s",
- e->n.addr, sr->router_id, sr->seqno, sr->nbr->addr, sr->nbr->ifa->ifname);
+ e->n.addr, sr->router_id, sr->seqno, n->addr, n->ifa->ifname);
- babel_send_unicast(&msg, sr->nbr->ifa, sr->nbr->addr);
+ babel_send_unicast(&msg, n->ifa, n->addr);
}
else
{
@@ -1285,10 +1303,13 @@ babel_handle_update(union babel_msg *m, struct babel_iface *ifa)
metric = babel_compute_metric(nbr, msg->metric);
best = e->selected;
- /* RFC section 3.8.2.2 - Dealing with unfeasible updates */
+ /*
+ * RFC section 3.8.2.2 - Dealing with unfeasible updates. Generate a one-off
+ * (not retransmitted) unicast seqno request to the originator of this update
+ */
if (!feasible && (metric != BABEL_INFINITY) &&
(!best || (r == best) || (metric < best->metric)))
- babel_add_seqno_request(p, e, s->router_id, s->seqno + 1, 0, nbr);
+ babel_generate_seqno_request(p, e, s->router_id, s->seqno + 1, nbr);
/* Special case - ignore unfeasible update to best route */
if (r == best && !feasible && (msg->router_id == r->router_id))
@@ -1353,6 +1374,32 @@ babel_handle_route_request(union babel_msg *m, struct babel_iface *ifa)
}
}
+static struct babel_neighbor *
+babel_find_seqno_request_target(struct babel_entry *e, struct babel_neighbor *skip)
+{
+ struct babel_route *r, *best_feasible = NULL, *best_any = NULL;
+
+ WALK_LIST(r, e->routes)
+ {
+ if (r->neigh == skip)
+ continue;
+
+ if (r->feasible && (!best_feasible || r->metric < best_feasible->metric))
+ best_feasible = r;
+
+ if (!best_any || r->metric < best_any->metric)
+ best_any = r;
+ }
+
+ if (best_feasible)
+ return best_feasible->neigh;
+
+ if (best_any)
+ return best_any->neigh;
+
+ return NULL;
+}
+
void
babel_handle_seqno_request(union babel_msg *m, struct babel_iface *ifa)
{
@@ -1389,26 +1436,21 @@ babel_handle_seqno_request(union babel_msg *m, struct babel_iface *ifa)
{
/* Not ours; forward if TTL allows it */
- /* Find best admissible route */
- struct babel_route *r, *best1 = NULL, *best2 = NULL;
- WALK_LIST(r, e->routes)
- if ((r->router_id == msg->router_id) && !ipa_equal(r->neigh->addr, msg->sender))
- {
- /* Find best feasible route */
- if ((!best1 || r->metric < best1->metric) && r->feasible)
- best1 = r;
+ struct babel_neighbor *nbr, *target;
- /* Find best not necessary feasible route */
- if (!best2 || r->metric < best2->metric)
- best2 = r;
- }
+ nbr = babel_find_neighbor(ifa, msg->sender);
+ if (!nbr)
+ return;
- /* If no route is found, do nothing */
- r = best1 ?: best2;
- if (!r)
+ target = babel_find_seqno_request_target(e, nbr);
+ if (!target)
+ {
+ TRACE(D_PACKETS, "No neighbor to forward seqno request for %N router-id %lR seqno %d to",
+ e->n.addr, msg->router_id, msg->seqno);
return;
+ }
- babel_add_seqno_request(p, e, msg->router_id, msg->seqno, msg->hop_count-1, r->neigh);
+ babel_add_seqno_request(p, e, msg->router_id, msg->seqno, msg->hop_count-1, target);
}
}
diff --git a/proto/babel/babel.h b/proto/babel/babel.h
index 8b6da3c8ce917440584d74f86d59eac4dcf60c84..da8386b3b76a63442d3e6153630ec881ee0e13ec 100644
--- a/proto/babel/babel.h
+++ b/proto/babel/babel.h
@@ -48,6 +48,8 @@
#define BABEL_ROUTE_REFRESH_FACTOR(X) ((btime)(X)*5/2) /* 2.5 */
#define BABEL_SEQNO_REQUEST_RETRY 4
#define BABEL_SEQNO_REQUEST_EXPIRY (2 S_)
+#define BABEL_SEQNO_FORWARD_EXPIRY (10 S_)
+#define BABEL_SEQNO_DUP_SUPPRESS_TIME (1 S_)
#define BABEL_GARBAGE_INTERVAL (300 S_)
#define BABEL_RXCOST_WIRED 96
#define BABEL_RXCOST_WIRELESS 256
@@ -240,7 +242,6 @@ struct babel_neighbor {
btime init_expiry;
list routes; /* Routes this neighbour has sent us (struct babel_route) */
- list requests; /* Seqno requests bound to this neighbor */
};
struct babel_source {
@@ -270,13 +271,13 @@ struct babel_route {
struct babel_seqno_request {
node n;
- node nbr_node;
u64 router_id;
u16 seqno;
+ u8 forwarded;
u8 hop_count;
u8 count;
btime expires;
- struct babel_neighbor *nbr;
+ btime dup_suppress_time;
};
struct babel_entry {