From a8873733dcbca6f5f83dcdae1ccfefb95bcb18ab Mon Sep 17 00:00:00 2001
From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Sun, 4 Aug 2013 00:48:53 +0200
Subject: Cleanup nexthop maintenance logic

---
 src/babel.h |  2 ++
 src/route.c | 85 +++++++++++++++++++++++++++++++++----------------------------
 2 files changed, 48 insertions(+), 39 deletions(-)

diff --git a/src/babel.h b/src/babel.h
index 625b570..0e1ebb9 100644
--- a/src/babel.h
+++ b/src/babel.h
@@ -103,6 +103,8 @@ struct gp_babel_route {
 
 	gp_babel_nexthop_t *selected;
 	gp_babel_nexthop_t *nexthops;
+
+	gmrf_time_t last_nexthop;
 };
 
 struct gp_babel_nexthop {
diff --git a/src/route.c b/src/route.c
index db89896..ccb2d84 100644
--- a/src/route.c
+++ b/src/route.c
@@ -27,6 +27,7 @@
 #include "babel.h"
 #include "neigh.h"
 
+#include <assert.h>
 #include <stdlib.h>
 
 
@@ -88,51 +89,52 @@ gp_babel_nexthop_t* gp_babel_route_nexthop_new(gp_babel_route_t *route, gp_babel
 	return nexthop;
 }
 
-static void maintain_nexthops(gmrf_context_t *ctx, gp_babel_route_t *route) {
-	gp_babel_nexthop_t **cur, **next;
-	for (cur = &route->nexthops; *cur; cur = next) {
-		gp_babel_nexthop_t *nexthop = *cur;
-		next = &nexthop->next;
+static inline bool nexthop_has_expired(gmrf_context_t *ctx, gp_babel_nexthop_t *nexthop) {
+	return (gp_babel_since(ctx, nexthop->last_update) > GP_BABEL_UPDATE_TIMEOUT(nexthop->interval));
+}
 
-		if (!nexthop->neigh) /* local */
-			continue;
+static void nexthop_delete(gmrf_context_t *ctx, gp_babel_route_t *route, gp_babel_nexthop_t *nexthop) {
+	gp_babel_nexthop_t **nexthopp;
+	for (nexthopp = &route->nexthops; *nexthopp; nexthopp = &(*nexthopp)->next) {
+		if (*nexthopp == nexthop)
+			break;
+	}
+	assert(*nexthopp == nexthop);
 
-		if (!nexthop->neigh->iface) {
-			// TODO find out what this is supposed to to
+	*nexthopp = nexthop->next;
 
-			if (nexthop->metric_seqno.metric != GP_BABEL_INFINITY) {
-				nexthop->metric_seqno.metric = GP_BABEL_INFINITY;
-				nexthop->last_update = gmrf_now(ctx->gmrf);
-				nexthop->last_update += GP_BABEL_UPDATE_TIMEOUT(nexthop->interval)*10;
-			}
+	if (route->selected == nexthop)
+		route->selected = NULL;
 
-			continue;
-		}
+	gp_babel_neigh_unref(nexthop->neigh);
+	free(nexthop);
 
-		if (gp_babel_since(ctx, nexthop->last_update) > GP_BABEL_UPDATE_TIMEOUT(nexthop->interval)) {
-			if (nexthop->metric_seqno.metric == GP_BABEL_INFINITY) {
-				*cur = *next;
-				next = cur;
+	route->last_nexthop = gmrf_now(ctx->gmrf);
+}
 
-				if (route->selected == nexthop)
-					route->selected = NULL;
+static void maintain_nexthop(gmrf_context_t *ctx, gp_babel_route_t *route, gp_babel_nexthop_t *nexthop) {
+	if (!nexthop->neigh) /* local */
+		return;
 
-				gp_babel_neigh_unref(nexthop->neigh);
+	if (nexthop_has_expired(ctx, nexthop)) {
+		nexthop_delete(ctx, route, nexthop);
+		return;
+	}
 
-				free(nexthop);
-			}
-			else {
-				nexthop->metric_seqno.metric = GP_BABEL_INFINITY;
-				nexthop->last_update += GP_BABEL_UPDATE_TIMEOUT(nexthop->interval)*10;
-			}
-		}
-		else if (gp_babel_since(ctx, nexthop->last_update) > GP_BABEL_UPDATE_REQUEST_TIMEOUT(nexthop->interval) && route->selected == nexthop) {
-			if (!nexthop->requested_update) {
-				gmrf_logf(ctx->gmrf, LOG_INFO, "route about to expire, requesting update");
-				gp_babel_send_route_request(ctx, NULL, nexthop->neigh, &route->node);
-				nexthop->requested_update = true;
-			}
-		}
+	if (gp_babel_since(ctx, nexthop->last_update) > GP_BABEL_UPDATE_REQUEST_TIMEOUT(nexthop->interval)
+	    && route->selected == nexthop && !nexthop->requested_update) {
+		gmrf_logf(ctx->gmrf, LOG_INFO, "route about to expire, requesting update");
+		gp_babel_send_route_request(ctx, NULL, nexthop->neigh, &route->node);
+		nexthop->requested_update = true;
+	}
+}
+
+static void maintain_nexthops(gmrf_context_t *ctx, gp_babel_route_t *route) {
+	gp_babel_nexthop_t *nexthop, *next;
+	for (nexthop = route->nexthops; nexthop; nexthop = next) {
+		next = nexthop->next;
+
+		maintain_nexthop(ctx, route, nexthop);
 	}
 }
 
@@ -190,12 +192,17 @@ void gp_babel_route_update(gmrf_context_t *ctx, gp_babel_route_t *route) {
 }
 
 void gp_babel_route_update_nexthop(gmrf_context_t *ctx, gp_babel_route_t *route, gp_babel_nexthop_t *nexthop, gp_babel_metric_seqno_t ms, uint16_t interval) {
-	if (ms.metric != GP_BABEL_INFINITY || nexthop->metric_seqno.metric != GP_BABEL_INFINITY)
-		nexthop->last_update = gmrf_now(ctx->gmrf);
+	if (ms.metric == GP_BABEL_INFINITY) {
+		gmrf_logf(ctx->gmrf, LOG_DEBUG, "retract received, deleting nexthop");
+		nexthop_delete(ctx, route, nexthop);
+		gp_babel_route_update(ctx, route);
+		return;
+	}
 
 	nexthop->metric_seqno = ms;
 	nexthop->interval = interval;
 	nexthop->requested_update = false;
+	nexthop->last_update = gmrf_now(ctx->gmrf);
 
 	gp_babel_route_update(ctx, route);
 }
-- 
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