iproute2 add hoplimit parsing and update usage and documentation

- Parse and handle the hoplimit ip route option and add it to the usage
  line and documentation.

- Add the missing reordering ip route option to the usage line.

- Add documentation for initcwnd ip route option.

Tested by setting hoplimit and retreiving it via "show".
Signed-off-by: Gilad Ben-Yossef <gilad@codefidence.com>
[ported to HEAD, fixed a bug with hoplimit lock handling, added documentation]
Signed-off-by: Ori Finkelman <ori@comsleep.com>
Signed-off-by: Yony Amit <yony@comsleep.com>

doc/ip-cref.tex

@@ -1324,7 +1324,17 @@ peers are allowed to send to us.
     If it is not given, Linux uses the value selected with \verb|sysctl|
     variable \verb|net/ipv4/tcp_reordering|.
 
+\item \verb|hoplimit NUMBER|
 
+--- [2.5.74+ only] Maximum number of hops on the path to this destination.
+    The default is the value selected with the \verb|sysctl| variable
+    \verb|net/ipv4/ip_default_ttl|.
+
+\item \verb|initcwnd NUMBER|
+--- [2.5.70+ only] Initial congestion window size for connections to
+    this destination. Actual window size is this value multiplied by the
+    MSS (``Maximal Segment Size'') for same connection. The default is
+    zero, meaning to use the values specified in~\cite{RFC2414}.
 
 \item \verb|nexthop NEXTHOP|
 
@@ -2653,6 +2663,9 @@ http://www.cisco.com/univercd/cc/td/doc/product/software/ios120.
 \bibitem{RFC-DHCP} R.~Droms.
 ``Dynamic Host Configuration Protocol.'', RFC-2131
 
+\bibitem{RFC2414}  M.~Allman, S.~Floyd, C.~Partridge.
+``Increasing TCP's Initial Window'', RFC-2414.
+
 \end{thebibliography}
 
 

ip/iproute.c

@@ -65,10 +65,10 @@ static void usage(void)
 	fprintf(stderr, "INFO_SPEC := NH OPTIONS FLAGS [ nexthop NH ]...\n");
 	fprintf(stderr, "NH := [ via ADDRESS ] [ dev STRING ] [ weight NUMBER ] NHFLAGS\n");
 	fprintf(stderr, "OPTIONS := FLAGS [ mtu NUMBER ] [ advmss NUMBER ]\n");
-	fprintf(stderr, "           [ rtt TIME ] [ rttvar TIME ]\n");
+	fprintf(stderr, "           [ rtt TIME ] [ rttvar TIME ] [reordering NUMBER ]\n");
 	fprintf(stderr, "           [ window NUMBER] [ cwnd NUMBER ] [ initcwnd NUMBER ]\n");
 	fprintf(stderr, "           [ ssthresh NUMBER ] [ realms REALM ] [ src ADDRESS ]\n");
-	fprintf(stderr, "           [ rto_min TIME ]\n");
+	fprintf(stderr, "           [ rto_min TIME ] [ hoplimit NUMBER ] \n");
 	fprintf(stderr, "TYPE := [ unicast | local | broadcast | multicast | throw |\n");
 	fprintf(stderr, "          unreachable | prohibit | blackhole | nat ]\n");
 	fprintf(stderr, "TABLE_ID := [ local | main | default | all | NUMBER ]\n");
@@ -763,6 +763,18 @@ int iproute_modify(int cmd, unsigned flags, int argc, char **argv)
 			if (get_unsigned(&mtu, *argv, 0))
 				invarg("\"mtu\" value is invalid\n", *argv);
 			rta_addattr32(mxrta, sizeof(mxbuf), RTAX_MTU, mtu);
+#ifdef RTAX_HOPLIMIT
+		} else if (strcmp(*argv, "hoplimit") == 0) {
+			unsigned hoplimit;
+			NEXT_ARG();
+			if (strcmp(*argv, "lock") == 0) {
+				mxlock |= (1<<RTAX_HOPLIMIT);
+				NEXT_ARG();
+			}
+			if (get_unsigned(&hoplimit, *argv, 0))
+				invarg("\"hoplimit\" value is invalid\n", *argv);
+			rta_addattr32(mxrta, sizeof(mxbuf), RTAX_HOPLIMIT, hoplimit);
+#endif
 #ifdef RTAX_ADVMSS
 		} else if (strcmp(*argv, "advmss") == 0) {
 			unsigned mss;