[PATCH 1/1] ping: Fix hop limit (TTL) handling for IPv6

[Radoslav Kolev]

Setting the hop limit was not implemented for IPv6. Also there was
a hack to override IPV6_HOPLIMIT to the value of IPV6_2292HOPLIMIT,
which was only introduced for backwards compatibility when RFC 3542
superseded RFC 2292. The proper way is to use IPV6_RECVHOPLIMIT in
the setsockopt call when requesting the value and IPV6_HOPLIMIT only
when retrieving it.

Signed-off-by: Radoslav Kolev <radoslav.kolev at suse.com>
---
 networking/ping.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/networking/ping.c b/networking/ping.c
index b7e6955a9..4e1979d5a 100644
--- a/networking/ping.c
+++ b/networking/ping.c
@@ -92,8 +92,7 @@
 //usage:     "\n	-s SIZE		Send SIZE data bytes in packets (default 56)"
 //usage:     "\n	-i SECS		Interval"
 //usage:     "\n	-A		Ping as soon as reply is received"
-///////:     "\n	-t TTL		Set TTL"
-///////^^^^^ -t not tested for IPv6, might be not working
+//usage:     "\n	-t TTL		Set TTL"
 //usage:     "\n	-I IFACE/IP	Source interface or IP address"
 //usage:     "\n	-W SEC		Seconds to wait for the first response (default 10)"
 //usage:     "\n			(after all -c CNT packets are sent)"
@@ -156,12 +155,6 @@
 
 #if ENABLE_PING6
 # include <netinet/icmp6.h>
-/* I see RENUMBERED constants in bits/in.h - !!?
- * What a fuck is going on with libc? Is it a glibc joke? */
-# ifdef IPV6_2292HOPLIMIT
-#  undef IPV6_HOPLIMIT
-#  define IPV6_HOPLIMIT IPV6_2292HOPLIMIT
-# endif
 #endif
 
 #if defined(__FreeBSD__)
@@ -844,6 +837,12 @@ static void ping6(len_and_sockaddr *lsa)
 	/* enable broadcast pings */
 	setsockopt_broadcast(pingsock);
 
+	if (opt_ttl != 0) {
+		setsockopt_int(pingsock, IPPROTO_IPV6, IPV6_UNICAST_HOPS, opt_ttl);
+		/* above doesn't affect packets sent to bcast IP, so... */
+		setsockopt_int(pingsock, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, opt_ttl);
+	}
+
 	/* set recv buf (needed if we can get lots of responses: flood ping,
 	 * broadcast ping etc) */
 	sockopt = (datalen * 2) + 7 * 1024; /* giving it a bit of extra room */
@@ -854,7 +853,7 @@ static void ping6(len_and_sockaddr *lsa)
 	setsockopt_int(pingsock, SOL_RAW, IPV6_CHECKSUM, sockopt);
 
 	/* request ttl info to be returned in ancillary data */
-	setsockopt_1(pingsock, SOL_IPV6, IPV6_HOPLIMIT);
+	setsockopt_1(pingsock, SOL_IPV6, IPV6_RECVHOPLIMIT);
 
 	if (if_index)
 		pingaddr.sin6.sin6_scope_id = if_index;
-- 
2.49.0