From bf2dc85619aa8253659fe478f7511b9b519c3529 Mon Sep 17 00:00:00 2001
From: Laurent Ghigonis <laurent@p1sec.com>
Date: Fri, 28 Jun 2013 01:31:13 +0200
Subject: libglouglou: traceroute: improve hops counting

---
 libglouglou/libggnet_traceroute.c | 66 +++++++++++++++++++++------------------
 libglouglou/libggnet_traceroute.h |  3 +-
 2 files changed, 38 insertions(+), 31 deletions(-)

diff --git a/libglouglou/libggnet_traceroute.c b/libglouglou/libggnet_traceroute.c
index 352cb0b..c7b095b 100644
--- a/libglouglou/libggnet_traceroute.c
+++ b/libglouglou/libggnet_traceroute.c
@@ -83,8 +83,7 @@ static struct ggnet_traceroute_hop *
 	_hop_ip_id(struct ggnet_traceroute_req *, int);
 static struct ggnet_traceroute_hop *
 	_hop_sport(struct ggnet_traceroute_req *, int);
-static struct ggnet_traceroute_hop *
-	_hop_last(struct ggnet_traceroute_req *);
+static void _trace_done(struct ggnet_traceroute_req *);
 static int pcap_dloff(pcap_t *); // XXX move to libggnet_utils ?
 double timeval_diff(struct timeval *, struct timeval *);
 
@@ -259,10 +258,12 @@ ggnet_traceroute_report(struct ggnet_traceroute_req *req) {
 #define left (sizeof(report) - (p - report))
 
 	p = report;
-	if (req->hopcount != 0)
-		p += (u_char)snprintf(p, left, "%d hops\n", req->hopcount);
+	if (req->target->ttl > 0)
+		p += (u_char)snprintf(p, left, "target:\t\tanswering\n");
 	else
-		p += (u_char)snprintf(p, left, "target not answering\n");
+		p += (u_char)snprintf(p, left, "target:\t\tnot answering\n");
+	p += (u_char)snprintf(p, left, "hops total:\t%d\n", req->hopcount_total);
+	p += (u_char)snprintf(p, left, "hops answering:\t%d\n", req->hopcount_answering);
 	TAILQ_FOREACH(hop, &req->hops_list, entry) {
 		p += (u_char)snprintf(p, left, "%.2d: %s %s %.2f [XXX %p]\n", hop->ttl, addr_ntoa(&hop->ip), hop->answer, hop->delay, hop);
 	}
@@ -486,19 +487,13 @@ static void
 _cb_trace_timeout(evutil_socket_t fd, short what, void *arg)
 {
 	struct ggnet_traceroute_req *req;
-	struct ggnet_traceroute_hop *last;
 
 	req = arg;
 
 	if (req->ggtr->verbose)
 		printf("XXX cbggnet_traceroute cb_trace_timeout (%s -> %s)\n",
 			addr_ntoa(&req->srcip), addr_ntoa(&req->target->ip));
-	last = _hop_last(req);
-	if (req->ggtr->verbose)
-		printf("XXX last %p\n", last);
-	if (last)
-		req->target->ttl = last->ttl + 1;
-	req->cb_done(req, req->data);
+	_trace_done(req);
 }
 
 static void
@@ -538,30 +533,41 @@ _hop_sport(struct ggnet_traceroute_req *req, int sport)
 	return NULL;
 }
 
-/**
- * Returns the target hop, and clean the hops_list before calling user callback
- * Also sets the hopcount
+/** Called at the end of a traceroute
+ * - Clean the hops_list by removing last non-answering hops
+ * - Updates target ttl
+ * - Count answering and total hops
+ * - Calls user callback
  */
-static struct ggnet_traceroute_hop *
-_hop_last(struct ggnet_traceroute_req *req)
+static void
+_trace_done(struct ggnet_traceroute_req *req)
 {
-	struct ggnet_traceroute_hop *h, *ht;
-	struct ggnet_traceroute_hop *last = NULL;
-	int found = 0;
-	int count = 0;
-
-	TAILQ_FOREACH_SAFE(h, &req->hops_list, entry, ht) {
-		count++;
-		if (found)
+	struct ggnet_traceroute_hop *h, *ht, *hp;
+	int hopcount_total = 0;
+	int hopcount_answering = 0;
+
+	TAILQ_FOREACH_REVERSE_SAFE(h, &req->hops_list, tailhead, entry, ht) {
+		if (h->answer_count) {
+			if (addr_cmp(&h->ip, &req->target->ip) == 0) {
+				req->target->ttl = h->ttl + 1;
+				hp = TAILQ_PREV(h, tailhead, entry);
+				if (hp && (addr_cmp(&hp->ip, &req->target->ip) == 0)) {
+					TAILQ_REMOVE(&req->hops_list, h, entry);
+					continue;
+				}
+			}
+			hopcount_answering++;
+		}
+		if (hopcount_answering > 0)
+			hopcount_total++;
+		else {
 			TAILQ_REMOVE(&req->hops_list, h, entry);
-		else if (addr_cmp(&h->ip, &req->target->ip) == 0) {
-			last = h;
-			found = 1;
-			req->hopcount = count;
 		}
 	}
+	req->hopcount_total = hopcount_total;
+	req->hopcount_answering = hopcount_answering;
 
-	return last;
+	req->cb_done(req, req->data);
 }
 
 static int
diff --git a/libglouglou/libggnet_traceroute.h b/libglouglou/libggnet_traceroute.h
index dbbb9ec..1d28299 100644
--- a/libglouglou/libggnet_traceroute.h
+++ b/libglouglou/libggnet_traceroute.h
@@ -55,7 +55,8 @@ struct ggnet_traceroute_req {
 	struct ggnet_traceroute_hop *target;
 	struct addr srcip;
 	struct ggnet_traceroute_req_params *params;
-	int hopcount;
+	int hopcount_total;
+	int hopcount_answering;
 	TAILQ_HEAD(tailhead, ggnet_traceroute_hop) hops_list;
 	struct {
 		struct event *ev_recv;
-- 
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