udp_io, traceroute: Standardise IPv6 PKTINFO handling to be portable

The current standard (RFC 3542) is for IPV6_RECVPKTINFO to be given to
setsockopt, and IPV6_PKTINFO to be used as the packet type. Previously,
RFC 2292 required IPV6_PKTINFO to be used for both, but RFC 3542
re-purposed IPV6_PKTINFO when given to setsockopt. The special
Linux-specific IPV6_2292PKTINFO has the same semantics as IPV6_PKTINFO
in RFC 2292, but was introduced at the same time as IPV6_RECVPKTINFO.

Therefore, if we have IPV6_RECVPKTINFO available, we can use the RFC
3542 style, and if not, we assume that only the RFC 2292 API is
available, using IPV6_PKTINFO for both.

Signed-off-by: James Clarke <jrtc27@jrtc27.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/libbb/udp_io.c b/libbb/udp_io.c
index 6e3ef484e4a1f4419bdfce8807ba7ec14f922425..68355e6c4002ad3b1b027832e9facdd4864b9cb3 100644 (file)
--- a/libbb/udp_io.c
+++ b/libbb/udp_io.c
@@ -8,6 +8,10 @@
  */
 #include "libbb.h"
 
+#if defined(IPV6_PKTINFO) && !defined(IPV6_RECVPKTINFO)
+# define IPV6_RECVPKTINFO IPV6_PKTINFO
+#endif
+
 /*
  * This asks kernel to let us know dst addr/port of incoming packets
  * We don't check for errors here. Not supported == won't be used
@@ -18,8 +22,8 @@ socket_want_pktinfo(int fd UNUSED_PARAM)
 #ifdef IP_PKTINFO
        setsockopt_1(fd, IPPROTO_IP, IP_PKTINFO);
 #endif
-#if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
-       setsockopt_1(fd, IPPROTO_IPV6, IPV6_PKTINFO);
+#if ENABLE_FEATURE_IPV6 && defined(IPV6_RECVPKTINFO)
+       setsockopt_1(fd, IPPROTO_IPV6, IPV6_RECVPKTINFO);
 #endif
 }
 

diff --git a/networking/traceroute.c b/networking/traceroute.c
index df7122047d045ad8698629b466ae2e4c45b95fe5..6dcbc2faad39ca82387ebb3db4b7092f60d42467 100644 (file)
--- a/networking/traceroute.c
+++ b/networking/traceroute.c
@@ -311,6 +311,9 @@
 # ifndef SOL_IPV6
 #  define SOL_IPV6 IPPROTO_IPV6
 # endif
+# if defined(IPV6_PKTINFO) && !defined(IPV6_RECVPKTINFO)
+#  define IPV6_RECVPKTINFO IPV6_PKTINFO
+# endif
 #endif
 
 #include "libbb.h"
@@ -911,12 +914,7 @@ common_traceroute_main(int op, char **argv)
 #if ENABLE_TRACEROUTE6
        if (af == AF_INET6) {
                xmove_fd(xsocket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6), rcvsock);
-# ifdef IPV6_RECVPKTINFO
                setsockopt_1(rcvsock, SOL_IPV6, IPV6_RECVPKTINFO);
-               setsockopt_1(rcvsock, SOL_IPV6, IPV6_2292PKTINFO);
-# else
-               setsockopt_1(rcvsock, SOL_IPV6, IPV6_PKTINFO);
-# endif
        } else
 #endif
        {