From a934dcc3ce78b22a0ff4db5d353a3d8dcc2b5f1d Mon Sep 17 00:00:00 2001
From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Mon, 8 Oct 2012 00:01:10 +0200
Subject: Purge old neigh and announce entries

---
 ffd/announce.c | 31 +++++++++++++++++++++++++++++++
 ffd/ffd.c      | 56 ++++++++++++++++++++++++++++++++++++++++----------------
 ffd/ffd.h      |  2 ++
 3 files changed, 73 insertions(+), 16 deletions(-)

diff --git a/ffd/announce.c b/ffd/announce.c
index 99bf1aa..6b30ec6 100644
--- a/ffd/announce.c
+++ b/ffd/announce.c
@@ -28,6 +28,35 @@
 #include "neigh.h"
 
 
+static void maintain_nexthops(ffd_announce_t *announce) {
+	ffd_nexthop_t **cur, **next;
+	for (cur = &announce->nexthop_list; *cur; cur = next) {
+		ffd_nexthop_t *nexthop = *cur;
+		next = &nexthop->next;
+
+		if (!nexthop->neigh) /* local */
+			continue;
+
+		if (timespec_diff(&now, &nexthop->last_update) > FFD_UPDATE_TIMEOUT(nexthop->interval)) {
+			if (nexthop->metric_seqno.metric == 0xffff) {
+				*cur = *next;
+				next = cur;
+
+				if (announce->selected == nexthop)
+					announce->selected = NULL;
+
+				nexthop->neigh->nexthop_refs--;
+
+				free(nexthop);
+			}
+			else {
+				nexthop->metric_seqno.metric = 0xffff;
+				add_interval(&nexthop->last_update, FFD_UPDATE_TIMEOUT(nexthop->interval));
+			}
+		}
+	}
+}
+
 static ffd_nexthop_t* select_nexthop(const ffd_announce_t *announce) {
 	uint16_t ret_metric = 0xffff;
 	ffd_nexthop_t *ret = NULL;
@@ -63,6 +92,8 @@ ffd_metric_seqno_t get_metric(const ffd_announce_t *announce) {
 }
 
 void ffd_announce_update(ffd_announce_t *announce) {
+	maintain_nexthops(announce);
+
 	announce->selected = select_nexthop(announce);
 	announce->metric = get_metric(announce);
 }
diff --git a/ffd/ffd.c b/ffd/ffd.c
index ee1e3ea..7cc3d3f 100644
--- a/ffd/ffd.c
+++ b/ffd/ffd.c
@@ -320,6 +320,8 @@ static ffd_nexthop_t* new_nexthop(ffd_announce_t *announce, ffd_neigh_t *neigh)
 	nexthop->next = announce->nexthop_list;
 	announce->nexthop_list = nexthop;
 
+	neigh->nexthop_refs++;
+
 	return nexthop;
 }
 
@@ -475,8 +477,19 @@ static void send_updates(void) {
 static void maintenance(void) {
 	ffd_iface_t *iface;
 	for (iface = iface_list; iface; iface = iface->next) {
-		ffd_neigh_t *neigh;
-		for (neigh = iface->neigh_list; neigh; neigh = neigh->next) {
+		ffd_neigh_t **cur, **next;
+		for (cur = &iface->neigh_list; *cur; cur = next) {
+			ffd_neigh_t *neigh = *cur;
+			next = &neigh->next;
+
+			if (ffd_neigh_get_rxcost(neigh) == 0xffff && ffd_neigh_get_txcost(neigh) == 0xffff && !neigh->nexthop_refs) {
+				*cur = *next;
+				next = cur;
+				free(neigh);
+
+				continue;
+			}
+
 			fprintf(stderr, "debug: maintenance: %02x:%02x:%02x:%02x:%02x:%02x[%s]: %u (rx %u/tx %u)\n",
 				neigh->addr.d[0], neigh->addr.d[1], neigh->addr.d[2],
 				neigh->addr.d[3], neigh->addr.d[4], neigh->addr.d[5],
@@ -484,28 +497,39 @@ static void maintenance(void) {
 		}
 	}
 
-	ffd_announce_t *announce;
-	for (announce = announce_list; announce; announce = announce->next) {
+	ffd_announce_t **cur, **next;
+	for (cur = &announce_list; *cur; cur = next) {
+		ffd_announce_t *announce = *cur;
+		next = &announce->next;
+
 		ffd_announce_update(announce);
 
-		fprintf(stderr, "debug: maintenance: node %04x%04x, type %04x, announce %04x: ", ntohl(*(uint32_t*)announce->node.id), ntohl(*(uint32_t*)(announce->node.id+4)), announce->type, announce->key);
+		if (!announce->nexthop_list) {
+			*cur = *next;
+			next = cur;
+			free(announce);
 
-		if (!announce->selected) {
-			fprintf(stderr, "nexthop: none\n");
 			continue;
 		}
 
-		ffd_neigh_t *neigh = announce->selected->neigh;
+		fprintf(stderr, "debug: node %04x%04x, type %04x, announce %04x (%u, seqno=%04x):\n",
+			ntohl(*(uint32_t*)announce->node.id), ntohl(*(uint32_t*)(announce->node.id+4)), announce->type, announce->key, announce->metric.metric, announce->metric.seqno);
 
-		if (!neigh) {
-			fprintf(stderr, "local\n");
-			continue;
-		}
+		ffd_nexthop_t *nexthop;
+		for (nexthop = announce->nexthop_list; nexthop; nexthop = nexthop->next) {
+			ffd_neigh_t *neigh = nexthop->neigh;
+
+			if (!neigh) {
+				fprintf(stderr, "\tlocal\n");
+				continue;
+			}
 
-		fprintf(stderr, "nexthop: %02x:%02x:%02x:%02x:%02x:%02x (%u, seqno=%04x)\n",
-			neigh->addr.d[0], neigh->addr.d[1], neigh->addr.d[2],
-			neigh->addr.d[3], neigh->addr.d[4], neigh->addr.d[5],
-			announce->metric.metric, announce->metric.seqno);
+			fprintf(stderr, "\tnexthop: %02x:%02x:%02x:%02x:%02x:%02x (%u, seqno=%04x, cost=%u%s)\n",
+				neigh->addr.d[0], neigh->addr.d[1], neigh->addr.d[2],
+				neigh->addr.d[3], neigh->addr.d[4], neigh->addr.d[5],
+				nexthop->metric_seqno.metric, nexthop->metric_seqno.seqno, ffd_neigh_get_cost(neigh),
+				(nexthop == announce->selected) ? ", selected" : "");
+		}
 	}
 }
 
diff --git a/ffd/ffd.h b/ffd/ffd.h
index fa2c378..9bd0d2c 100644
--- a/ffd/ffd.h
+++ b/ffd/ffd.h
@@ -91,6 +91,8 @@ typedef struct _ffd_announce_t {
 typedef struct _ffd_neigh_t {
 	struct _ffd_neigh_t *next;
 
+	unsigned nexthop_refs;
+
 	/* for actual routing, we'd also have to link back to the iface
 	   this neighbour belongs to */
 	eth_addr_t addr;
-- 
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