Michael Richardson wrote:

-	if (tb[RTA_PROTOINFO]) {
-		fprintf(fp, "fwmark %#x ", *(__u32*)RTA_DATA(tb[RTA_PROTOINFO]));
+	if (tb[RTA_FWMARK]) {
+		__u32 value = *(__u32*)RTA_DATA(tb[RTA_PROTOINFO]);
+		if (tb[RTA_FWMARK_MASK]) {
+			__u32 mask;
+			mask=*(__u32*)RTA_DATA(tb[RTA_FWMARK_MASK]);
+			fprintf(fp, "fwmark %#x&%#x ", value, mask);

The normal way to display masks is with a "/". Also I think it shouldn't
display the default mask to avoid breaking scripts that parse the
output.

+		} else if (strcmp(*argv, "fwmarkmask") == 0) {
+			__u32 fwmarkmask;
+			NEXT_ARG();
+			if (get_u32(&fwmarkmask, *argv, 0))
+				invarg("fwmarkmask value is invalid\n", *argv);
+			addattr32(&req.n, sizeof(req), RTA_FWMARK_MASK, fwmarkmask);

ip should be able to parse its own output, and it would also look nicer
if I could just say "fwmark 0x1/32". fwmarkmask is really an incredible
ugly expression :)