--- src/usr.bin/nc/nc.1

+++ src/usr.bin/nc/nc.1

@@ -153,6 +153,8 @@ instead of sequentially within a range or in the order that the system

 assigns them.

 .It Fl S

 Enables the RFC 2385 TCP MD5 signature option.

+.Ar NOTE:

+This option is supported under OpenBSD, but not under Linux yet.

 .It Fl s Ar source_ip_address

 Specifies the IP of the interface which is used to send the packets.

 It is an error to use this option in conjunction with the

@@ -182,6 +184,8 @@ Use UDP instead of the default option of TCP.

 .It Fl V Ar rtable

 Set the routing table to be used.

 The default is 0.

+.Ar NOTE:

+This option is supported under OpenBSD, but not under Linux yet.

 .It Fl v

 Have

 .Nm

--- src/usr.bin/nc/netcat.c

+++ src/usr.bin/nc/netcat.c

@@ -56,6 +56,18 @@

 #include "atomicio.h"

 #include <time.h>

+#ifdef TCP_MD5SIG

+# define HAVE_TCP_MD5SIG 1

+#endif

+

+#ifdef SO_JUMBO

+# define HAVE_SO_JUMBO 1

+#endif

+

+#ifdef SO_RTABLE

+# define HAVE_SO_RTABLE 1

+#endif

+

 #ifndef SUN_LEN

 #define SUN_LEN(su) \

 	(sizeof(*(su)) - sizeof((su)->sun_path) + strlen((su)->sun_path))

@@ -67,7 +79,9 @@

 /* Command Line Options */

 int	dflag;					/* detached, no stdin */

 unsigned int iflag;				/* Interval Flag */

+#ifdef HAVE_SO_JUMBO

 int	jflag;					/* use jumbo frames if we can */

+#endif

 int	kflag;					/* More than one connect */

 int	lflag;					/* Bind to local port */

 int	nflag;					/* Don't do name look up */

@@ -83,9 +97,13 @@ int	zflag;					/* Port Scan Flag */

 int	Dflag;					/* sodebug */

 int	Iflag;					/* TCP receive buffer size */

 int	Oflag;					/* TCP send buffer size */

+#ifdef HAVE_TCP_MD5SIG

 int	Sflag;					/* TCP MD5 signature option */

+#endif

 int	Tflag = -1;				/* IP Type of Service */

+#ifdef HAVE_SO_RTABLE

 u_int	rtableid;

+#endif

 int timeout = -1;

 int family = AF_INET;

@@ -163,7 +181,11 @@ main(int argc, char *argv[])

 				errx(1, "interval %s: %s", errstr, optarg);

 			break;

 		case 'j':

+#ifdef HAVE_SO_JUMBO

 			jflag = 1;

+#else

+			errx(1, "-j requires SO_JUMBO kernel support that is missing under Linux yet");

+#endif

 			break;

 		case 'k':

 			kflag = 1;

@@ -194,10 +216,14 @@ main(int argc, char *argv[])

 			uflag = 1;

 			break;

 		case 'V':

+#ifdef HAVE_SO_RTABLE

 			rtableid = (unsigned int)strtonum(optarg, 0,

 			    RT_TABLEID_MAX, &errstr);

 			if (errstr)

 				errx(1, "rtable %s: %s", errstr, optarg);

+#else

+			errx(1, "-V requires SO_RTABLE kernel support that is missing under Linux yet");

+#endif

 			break;

 		case 'v':

 			vflag = 1;

@@ -232,7 +258,11 @@ main(int argc, char *argv[])

 				    errstr, optarg);

 			break;

 		case 'S':

+#ifdef HAVE_TCP_MD5SIG

 			Sflag = 1;

+#else

+			errx(1, "-S requires TCP_MD5SIG kernel support that is missing under Linux yet");

+#endif

 			break;

 		case 'T':

 			Tflag = parse_iptos(optarg);

@@ -332,7 +362,11 @@ main(int argc, char *argv[])

 				struct sockaddr_storage z;

 				len = sizeof(z);

+#ifdef HAVE_SO_JUMBO

 				plen = jflag ? 16384 : 2048;

+#else

+				plen = 2048;

+#endif

 				rv = recvfrom(s, buf, plen, MSG_PEEK,

 				    (struct sockaddr *)&z, &len);

 				if (rv < 0)

@@ -515,18 +549,22 @@ remote_connect(const char *host, const char *port, struct addrinfo hints)

 		    res0->ai_protocol)) < 0)

 			continue;

+#ifdef HAVE_SO_RTABLE

 		if (rtableid) {

 			if (setsockopt(s, IPPROTO_IP, SO_RTABLE, &rtableid,

 			    sizeof(rtableid)) == -1)

 				err(1, "setsockopt SO_RTABLE");

 		}

+#endif

 		/* Bind to a local port or source address if specified. */

 		if (sflag || pflag) {

 			struct addrinfo ahints, *ares;

+#ifdef SO_BINDANY

 			/* try SO_BINDANY, but don't insist */

 			setsockopt(s, SOL_SOCKET, SO_BINDANY, &on, sizeof(on));

+#endif

 			memset(&ahints, 0, sizeof(struct addrinfo));

 			ahints.ai_family = res0->ai_family;

 			ahints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM;

@@ -601,11 +639,13 @@ local_listen(char *host, char *port, struct addrinfo hints)

 		    res0->ai_protocol)) < 0)

 			continue;

+#ifdef HAVE_SO_RTABLE

 		if (rtableid) {

 			if (setsockopt(s, IPPROTO_IP, SO_RTABLE, &rtableid,

 			    sizeof(rtableid)) == -1)

 				err(1, "setsockopt SO_RTABLE");

 		}

+#endif

 		ret = setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &x, sizeof(x));

 		if (ret == -1)

@@ -645,7 +685,11 @@ readwrite(int nfd)

 	int lfd = fileno(stdout);

 	int plen;

+#ifdef HAVE_SO_JUMBO

 	plen = jflag ? 16384 : 2048;

+#else

+	plen = 2048;

+#endif

 	/* Setup Network FD */

 	pfd[0].fd = nfd;

@@ -808,21 +852,25 @@ set_common_sockopts(int s)

 {

 	int x = 1;

+#ifdef HAVE_TCP_MD5SIG

 	if (Sflag) {

 		if (setsockopt(s, IPPROTO_TCP, TCP_MD5SIG,

 			&x, sizeof(x)) == -1)

 			err(1, NULL);

 	}

+#endif

 	if (Dflag) {

 		if (setsockopt(s, SOL_SOCKET, SO_DEBUG,

 			&x, sizeof(x)) == -1)

 			err(1, NULL);

 	}

+#ifdef HAVE_SO_JUMBO

 	if (jflag) {

 		if (setsockopt(s, SOL_SOCKET, SO_JUMBO,

 			&x, sizeof(x)) == -1)

 			err(1, NULL);

 	}

+#endif

 	if (Tflag != -1) {

 		if (setsockopt(s, IPPROTO_IP, IP_TOS,

 		    &Tflag, sizeof(Tflag)) == -1)

@@ -875,15 +923,19 @@ help(void)

 	\t-O length	TCP send buffer length\n\

 	\t-P proxyuser\tUsername for proxy authentication\n\

 	\t-p port\t	Specify local port for remote connects\n\

-	\t-r		Randomize remote ports\n\

-	\t-S		Enable the TCP MD5 signature option\n\

-	\t-s addr\t	Local source address\n\

+	\t-r		Randomize remote ports\n"

+#ifdef HAVE_TCP_MD5SIG

+"	\t-S		Enable the TCP MD5 signature option\n"

+#endif

+"	\t-s addr\t	Local source address\n\

 	\t-T ToS\t	Set IP Type of Service\n\

 	\t-t		Answer TELNET negotiation\n\

 	\t-U		Use UNIX domain socket\n\

-	\t-u		UDP mode\n\

-	\t-V rtable	Specify alternate routing table\n\

-	\t-v		Verbose\n\

+	\t-u		UDP mode\n"

+#ifdef HAVE_SO_RTABLE

+"	\t-V rtable	Specify alternate routing table\n"

+#endif

+"	\t-v		Verbose\n\

 	\t-w secs\t	Timeout for connects and final net reads\n\

 	\t-X proto	Proxy protocol: \"4\", \"5\" (SOCKS) or \"connect\"\n\

 	\t-x addr[:port]\tSpecify proxy address and port\n\

@@ -896,9 +948,9 @@ void

 usage(int ret)

 {

 	fprintf(stderr,

-	    "usage: netcat [-46DdhklnrStUuvz] [-I length] [-i interval] [-O length]\n"

+	    "usage: netcat [-46DdhklnrtUuvz] [-I length] [-i interval] [-O length]\n"

 	    "              [-P proxy_username] [-p source_port] [-s source_ip_address] [-T ToS]\n"

-	    "              [-V rtable] [-w timeout] [-X proxy_protocol]\n"

+	    "              [-w timeout] [-X proxy_protocol]\n"

 	    "              [-x proxy_address[:port]] [hostname] [port]\n");

 	if (ret)

 		exit(1);