new address options shut-null, null-eof

CHANGES

@@ -1,7 +1,13 @@
 
 new features:
-	new address options shut-none, shut-down, and shut-close allow to
-	control socat's half close behaviour
+	address options shut-none, shut-down, and shut-close allow to control
+	socat's half close behaviour
+
+	with address option shut-null socat sends an empty packet to the peer
+	to indicate EOF
+
+	option null-eof changes the behaviour of sockets that receive an empty
+	packet to see EOF instead of ignoring it
 
 ####################### V 1.7.0.1:
 

VERSION

@@ -1 +1 @@
-"1.7.0.1"
+"1.7.0.1+shutnull"

doc/socat.yo

@@ -1490,6 +1490,16 @@ label(OPTION_SHUT_DOWN)dit(bf(tt(shut-down)))
 label(OPTION_SHUT_CLOSE)dit(bf(tt(shut-close)))
    Changes the (address dependent) method of shutting down the write part of a
    connection to tt(close\(fd)).
+label(OPTION_SHUT_NULL)dit(bf(tt(shut-null)))
+   When one address indicates EOF, socat() will send a zero sized packet to the
+   write channel of the other address to transfer the EOF condition. This is
+   useful with UDP and other datagram protocols. Has been tested against
+   netcat and socat with option link(null-eof)(OPTION_NULL_EOF).
+label(OPTION_NULL_EOF)dit(bf(tt(null-eof)))
+   Normally socat() will ignore empty (zero size payload) packets arriving on
+   datagram sockets, so it survives port scans. With this option socat()
+   interprets empty datagram packets as EOF indicator (see
+   link(shut-null)(OPTION_SHUT_NULL).
 label(OPTION_IOCTL_VOID)dit(bf(tt(ioctl-void=<request>)))
    Calls tt(ioctl()) with the request value as second argument and NULL as
    third argument. This option allows to utilize ioctls that are not

test.sh

@@ -7558,6 +7558,58 @@ esac
 N=$((N+1))
 
 
+# test the shut-null and null-eof options
+NAME=SHUTNULLEOF
+case "$TESTS" in
+*%functions%*|*%socket%*|*%$NAME%*)
+TEST="$NAME: options shut-null and null-eof"
+# run a receiving background process with option null-eof. 
+# start a sending process with option shut-null that sends a test record to the
+# receiving process and then terminates.
+# send another test record.
+# whe the receiving process just got the first test record the test succeeded
+if ! eval $NUMCOND; then :; else
+tf="$td/test$N.stout"
+te="$td/test$N.stderr"
+tdiff="$td/test$N.diff"
+da="test$N $(date) $RANDOM"
+CMD0="$SOCAT $opts -u UDP-RECV:$PORT,null-eof CREAT:$tf"
+CMD1="$SOCAT $opts -u - UDP-SENDTO:127.0.0.1:$PORT,shut-null"
+printf "test $F_n $TEST... " $N
+$CMD0 >/dev/null 2>"${te}0" &
+pid0=$!
+waitudp4port $PORT 1
+echo "$da" |$CMD1 >"${tf}1" 2>"${te}1"
+rc1=$?
+echo "xyz" |$CMD1 >"${tf}2" 2>"${te}2"
+rc2=$?
+kill $pid0 2>/dev/null; wait
+if [ $rc1 != 0 -o $rc2 != 0 ]; then
+    $PRINTF "$FAILED\n"
+    echo "$CMD0 &"
+    echo "$CMD1"
+    cat "${te}0"
+    cat "${te}1"
+    cat "${te}2"
+    numFAIL=$((numFAIL+1))
+elif echo "$da" |diff - "${tf}" >"$tdiff"; then
+    $PRINTF "$OK\n"
+    numOK=$((numOK+1))
+else
+    $PRINTF "$FAILED\n"
+    echo "$CMD0 &"
+    echo "$CMD1"
+    cat "${te}0"
+    cat "${te}1"
+    cat "${tdiff}"
+    numFAIL=$((numFAIL+1))
+fi
+fi # NUMCOND
+ ;;
+esac
+N=$((N+1))
+
+
 NAME=UDP6LISTENBIND
 # this tests for a bug in (up to) 1.5.0.0:
 #    with udp*-listen, the bind option supported only IPv4

xio-fd.c

@@ -78,6 +78,7 @@ const struct optdesc opt_end_close = { "end-close", "close", OPT_END_CLOSE, GROU
 const struct optdesc opt_shut_none = { "shut-none", NULL,    OPT_SHUT_NONE,  GROUP_FD, PH_INIT, TYPE_BOOL,  OFUNC_OFFSET, (bool)&((xiofile_t *)0)->stream.howtoshut, XIOSHUT_NONE };
 const struct optdesc opt_shut_down = { "shut-down", NULL,    OPT_SHUT_DOWN,  GROUP_FD, PH_INIT, TYPE_BOOL,  OFUNC_OFFSET, (bool)&((xiofile_t *)0)->stream.howtoshut, XIOSHUT_DOWN };
 const struct optdesc opt_shut_close= { "shut-close", NULL,   OPT_SHUT_CLOSE, GROUP_FD, PH_INIT, TYPE_BOOL,  OFUNC_OFFSET, (bool)&((xiofile_t *)0)->stream.howtoshut, XIOSHUT_CLOSE };
+const struct optdesc opt_shut_null = { "shut-null", NULL,        OPT_SHUT_NULL, GROUP_FD, PH_INIT, TYPE_CONST, OFUNC_OFFSET, (bool)&((xiofile_t *)0)->stream.howtoshut, XIOSHUT_NULL };
 
 /****** generic ioctl() options ******/
 const struct optdesc opt_ioctl_void   = { "ioctl-void",  "ioctl",    OPT_IOCTL_VOID,  GROUP_FD, PH_FD, TYPE_INT,       OFUNC_IOCTL_GENERIC, 0, 0, 0 };

xio-fd.h

@@ -45,6 +45,7 @@ extern const struct optdesc opt_end_close;
 extern const struct optdesc opt_shut_none;
 extern const struct optdesc opt_shut_down;
 extern const struct optdesc opt_shut_close;
+extern const struct optdesc opt_shut_null;
 extern const struct optdesc opt_streams_i_push;
 
 #endif /* !defined(__xio_fd_h_included) */

xio-socket.c

@@ -196,6 +196,8 @@ const struct optdesc opt_setsockopt_int    = { "setsockopt-int",    "sockopt-int
 const struct optdesc opt_setsockopt_bin    = { "setsockopt-bin",    "sockopt-bin",    OPT_SETSOCKOPT_BIN,        GROUP_SOCKET,PH_PASTSOCKET,TYPE_INT_INT_BIN,     OFUNC_SOCKOPT_GENERIC, 0, 0 };
 const struct optdesc opt_setsockopt_string = { "setsockopt-string", "sockopt-string", OPT_SETSOCKOPT_STRING,     GROUP_SOCKET,PH_PASTSOCKET,TYPE_INT_INT_STRING,  OFUNC_SOCKOPT_GENERIC, 0, 0 };
 
+const struct optdesc opt_null_eof = { "null-eof", NULL, OPT_NULL_EOF, GROUP_SOCKET, PH_INIT, TYPE_BOOL, OFUNC_OFFSET, (bool)&((xiofile_t *)0)->stream.para.socket.null_eof };
+
 
 #if WITH_GENERICSOCKET
 

xio-socket.h

@@ -1,5 +1,5 @@
 /* source: xio-socket.h */
-/* Copyright Gerhard Rieger 2001-2008 */
+/* Copyright Gerhard Rieger 2001-2009 */
 /* Published under the GNU General Public License V.2, see file COPYING */
 
 #ifndef __xio_socket_h_included
@@ -67,6 +67,7 @@ extern const struct optdesc opt_protocol_family;
 extern const struct optdesc opt_setsockopt_int;
 extern const struct optdesc opt_setsockopt_bin;
 extern const struct optdesc opt_setsockopt_string;
+extern const struct optdesc opt_null_eof;
 
 
 extern

xio.h

@@ -147,10 +147,11 @@ typedef struct single {
    char  *unlink_close;	/* name of a symlink or unix socket to be removed */
    int dtype;
    enum {
-      XIOSHUT_UNSPEC,	/* fall back to old (up to 1.7.0.0) behaviour */
+      XIOSHUT_UNSPEC,	/* standard (address dependent) behaviour */
       XIOSHUT_NONE,	/* do nothing on shutdown */
       XIOSHUT_CLOSE,	/* close the FD */
-      XIOSHUT_DOWN	/* shutdown() */
+      XIOSHUT_DOWN,	/* shutdown() */
+      XIOSHUT_NULL	/* send an empty packet (dgram socket) */
    } howtoshut;
    enum {
       END_UNSPEC,	/* after init, when no end-close... option */
@@ -183,7 +184,7 @@ typedef struct single {
       struct {
 	 struct timeval connect_timeout; /* how long to hang in connect() */
 	 union sockaddr_union la;	/* local socket address */
-	 bool emptyiseof;	/* with dgram: empty packet means EOF */
+	 bool null_eof;		/* with dgram: empty packet means EOF */
 	 bool dorange;
 	 struct xiorange range;	/* restrictions for peer address */
 #if _WITH_IP4 || _WITH_IP6

xioopts.c

@@ -926,6 +926,7 @@ const struct optname optionnames[] = {
 #ifdef O_NSHARE
 	IF_OPEN   ("nshare",	&opt_o_nshare)
 #endif
+	IF_SOCKET ("null-eof",		&opt_null_eof)
 #ifdef O_ASYNC
 	IF_ANY    ("o-async",		&opt_async)
 #endif
@@ -1316,6 +1317,7 @@ const struct optname optionnames[] = {
 	IF_ANY    ("shut-close",	&opt_shut_close)
 	IF_ANY    ("shut-down",	&opt_shut_down)
 	IF_ANY    ("shut-none",	&opt_shut_none)
+	IF_ANY    ("shut-null",		&opt_shut_null)
 #if WITH_EXEC || WITH_SYSTEM
 	IF_ANY    ("sid",	&opt_setsid)
 #endif

xioopts.h

@@ -444,6 +444,7 @@ enum e_optcode {
    OPT_NOFLSH,		/* termios.c_lflag */
    OPT_NOFORK,		/* exec, system */
    OPT_NOPROMPT,	/* readline */
+   OPT_NULL_EOF,		/* receiving empty packet triggers EOF */
 #ifdef OCRNL
    OPT_OCRNL,		/* termios.c_oflag */
 #endif
@@ -593,6 +594,7 @@ enum e_optcode {
    OPT_SHUT_CLOSE,
    OPT_SHUT_DOWN,
    OPT_SHUT_NONE,
+   OPT_SHUT_NULL,	/* send 0 bytes on shutdown */
    OPT_SIGHUP,
    OPT_SIGINT,
    OPT_SIGQUIT,

xioread.c

@@ -1,5 +1,5 @@
 /* source: xioread.c */
-/* Copyright Gerhard Rieger 2001-2008 */
+/* Copyright Gerhard Rieger 2001-2009 */
 /* Published under the GNU General Public License V.2, see file COPYING */
 
 /* this is the source of the extended read function */
@@ -159,7 +159,7 @@ ssize_t xioread(xiofile_t *file, void *buff, size_t bufsiz) {
 	      bytes,
 	      sockaddr_info(&from.soa, fromlen, infobuff, sizeof(infobuff)));
       if (bytes == 0) {
-	 if (!pipe->para.socket.emptyiseof) {
+	 if (!pipe->para.socket.null_eof) {
 	    errno = EAGAIN; return -1;
 	 }
 	 return bytes;
@@ -350,7 +350,7 @@ ssize_t xioread(xiofile_t *file, void *buff, size_t bufsiz) {
 	      bytes,
 	      sockaddr_info(&from.soa, fromlen, infobuff, sizeof(infobuff)));
       if (bytes == 0) {
-	 if (!pipe->para.socket.emptyiseof) {
+	 if (!pipe->para.socket.null_eof) {
 	    errno = EAGAIN; return -1;
 	 }
 	 return bytes;

xioshutdown.c

@@ -35,6 +35,7 @@ int xioshutdown(xiofile_t *sock, int how) {
    }
 
    switch (sock->stream.howtoshut) {
+      char writenull;
    case XIOSHUT_NONE:
       return 0;
    case XIOSHUT_CLOSE:
@@ -49,9 +50,16 @@ int xioshutdown(xiofile_t *sock, int how) {
 	       sock->stream.fd, how, strerror(errno));
       }
       return 0;
+#if _WITH_SOCKET
+   case XIOSHUT_NULL:
+      /* send an empty packet; only useful on datagram sockets? */
+      xiowrite(sock, &writenull, 0);
+      return 0;
+#endif /* _WITH_SOCKET */
    default: ;
    }
 
+
 #if WITH_OPENSSL
    if ((sock->stream.dtype & XIODATA_MASK) == XIODATA_OPENSSL) {
       sycSSL_shutdown (sock->stream.para.openssl.ssl);