IPv6 mobility: Print the protocol name before the checks

Use nd_print_protocol().

Update a test output.

Author: fxlb

print-mobility.c

@@ -208,6 +208,8 @@ mobility_print(netdissect_options *ndo,
 	uint8_t type;
 
 	ndo->ndo_protocol = "mobility";
+	nd_print_protocol(ndo);
+	ND_PRINT(": ");
 	mh = (const struct ip6_mobility *)bp;
 
 	/* 'ep' points to the end of available data. */
@@ -238,7 +240,7 @@ mobility_print(netdissect_options *ndo,
 		ND_PRINT("(header length %u is too small for type %u)", mhlen, type);
 		goto trunc;
 	}
-	ND_PRINT("mobility: %s", tok2str(ip6m_str, "type-#%u", type));
+	ND_PRINT("%s", tok2str(ip6m_str, "type-#%u", type));
 	switch (type) {
 	case IP6M_BINDING_REQUEST:
 		hlen = IP6M_MINLEN;

tests/cve2015-0261-ipv6.out

@@ -1,2 +1,2 @@
     1  2002-12-31 13:55:31.300000 IP6 [header+payload length 26510 > length 185] (invalid) (class 0x76, flowlabel 0x76767, hlim 103, next-header Mobility (135), payload length 26470) 6767:6767:6767:6767:6767:6767:6767:6767 > 6767:6767:6767:6767:6767:6767:6767:6705: mobility: BU seq#=26471 HL lifetime=105884(type-0x67: len=103) [|mobility]
-    2  2003-03-06 15:21:11.300000 IP6 [header+payload length 26510 > length 185] (invalid) (class 0x76, flowlabel 0x76767, hlim 103, next-header Mobility (135), payload length 26470) 6767:6767:6767:6767:6767:6767:6767:6767 > 6767:6767:4f67:6767:6767:6767:6767:6767: (header length 8 is too small for type 6) [|mobility]
+    2  2003-03-06 15:21:11.300000 IP6 [header+payload length 26510 > length 185] (invalid) (class 0x76, flowlabel 0x76767, hlim 103, next-header Mobility (135), payload length 26470) 6767:6767:6767:6767:6767:6767:6767:6767 > 6767:6767:4f67:6767:6767:6767:6767:6767: mobility: (header length 8 is too small for type 6) [|mobility]