o Added initial SCTP port scanning support to Nmap. SCTP is

a layer 4 protocol used mostly for telephony related applications.
  This brings the following new features:
  o SCTP INIT chunk port scan (-sY): open ports return an INIT-ACK
    chunk, closed ones an ABORT chunk.  This is the SCTP equivalent
    of a TCP SYN stealth scan.
  o SCTP COOKIE-ECHO chunk port scan (-sZ): open ports are silent,
    closed ports return an ABORT chunk.
  o SCTP INIT chunk ping probes (-PY): host discovery using SCTP
    INIT chunk packets.
  o SCTP-specific IP protocol scan (-sO -p sctp).
  o SCTP-specific traceroute support (--traceroute).
  o The ability to use the deprecated Adler32 algorithm as specified
    in RFC 2960 instead of CRC32C from RFC 4960 (--adler32).
  o 42 well-known SCTP ports were added to the nmap-services file.
  Part of the work on SCTP support was kindly sponsored by
  Compass Security AG, Switzerland.  [Daniel Roethlisberger]

protocols.h

@@ -111,4 +111,16 @@ struct protocol_list {
 int addprotocolsfromservmask(char *mask, u8 *porttbl);
 struct protoent *nmap_getprotbynum(int num);
 
+#define MAX_IPPROTOSTRLEN 4
+#define IPPROTO2STR(p)		\
+  ((p)==IPPROTO_TCP ? "tcp" :	\
+   (p)==IPPROTO_UDP ? "udp" :	\
+   (p)==IPPROTO_SCTP ? "sctp" :	\
+   "n/a")
+#define IPPROTO2STR_UC(p)	\
+  ((p)==IPPROTO_TCP ? "TCP" :	\
+   (p)==IPPROTO_UDP ? "UDP" :	\
+   (p)==IPPROTO_SCTP ? "SCTP" :	\
+   "N/A")
+
 #endif