X-Git-Url: https://git.distorted.org.uk/~mdw/userv-utils/blobdiff_plain/33b946d92ffbe495aee70d8a49d3314975494a63..8d9c58663412f651132b7f75ca3a49514cb1fd4d:/ipif/udptunnel?ds=sidebyside

diff --git a/ipif/udptunnel b/ipif/udptunnel
index dff18ed..1b5031c 100755
--- a/ipif/udptunnel
+++ b/ipif/udptunnel
@@ -3,6 +3,7 @@
 #
 # usage:
 #  udptunnel
+#        [ -l[<local-command/arg>] ... . ]
 #            <public-local-host/addr>,<public-local-port>
 #            <public-remote-host/addr>,<public-remote-port>
 #            <private-local-addr>,<private-remote-addr>,<mtu>,<proto>
@@ -24,6 +25,8 @@
 # udptunnel will userv ipif locally, as
 #    userv root ipif <private-local-addr>,<private-remote-addr>,<mtu>,<proto>
 #                    <extra-local-nets>
+# or, if -lc was given, userv root ipif is replaced with the argument(s) to
+# successive -lc options.
 
 use Socket;
 use POSIX;
@@ -68,6 +71,19 @@ sub show_addr_port ($) {
     return inet_ntoa($s[1]).','.$s[0];
 }
 
+@lcmd= ();
+
+while ($ARGV[0] =~ m/^-/) {
+    $_= shift @ARGV;
+    last if $_ eq '--';
+    if (s/^-l//) {
+	push @lcmd,$_ if length;
+	while (@ARGV && ($_= shift @ARGV) ne '-') { push @lcmd, $_; }
+    } else {
+	quit("unknown option \`$_'");
+    }
+}
+
 ($las,$lps)= eat_addr_port('print|silent');
 $la= conv_host_addr($las);
 $lp= conv_port_number($lps);
@@ -134,7 +150,11 @@ $rsp= show_addr_port($rs);
 
 if ($lps eq 'print') { print($lsp,"\n") or quit("write port to stdout: $!"); }
 
+@lcmd= qw(userv root ipif) unless @lcmd;
+
 debug("using remote $rsp local $lsp");
+push @lcmd, ("$lva,$rva,$mtu,$proto",$lepn);
+debug("local command @lcmd");
 
 pipe(UR,UW) or fail("up pipe");
 pipe(DR,DW) or fail("down pipe");
@@ -144,8 +164,8 @@ if (!$c3) {
     close UR; close DW;
     open(STDIN,"<&DR") or fail("reopen stdin for packets");
     open(STDOUT,">&UW") or fail("reopen stdout for packets");
-    exec "userv","root","ipif","$lva,$rva,$mtu,$proto",$lepn;
-    quit("cannot execute userv ipif: $!");
+    exec @lcmd;
+    quit("cannot execute $lcmd[0]: $!");
 }
 close UW;
 close DR;
@@ -175,17 +195,17 @@ if ($keepalive) { $nextsendka= now(); }
 for (;;) {
     if ($keepalive) {
 	$now= now();
-	$timeout= $nextsendka-$now;
-	if ($timeout < 0) {
+	$thistimeout= $nextsendka-$now;
+	if ($thistimeout < 0) {
 	    defined(send L,"\300",0,$rs)
 		or warning("transmit keepalive error: $!");
 	    $nextsendka= $now+$keepalive;
-	    $timeout= $keepalive;
+	    $thistimeout= $keepalive;
 	}
     } else {
-	$timeout= undef;
+	$thistimeout= undef;
     }
-    select($readfds=$wantreadfds,'','',$timeout);
+    select($readfds=$wantreadfds,'','',$thistimeout);
     for (;;) {
 	if (!defined($r= sysread(UR,$upbuf,$mtu*2+3,length($upbuf)))) {
 	    $! == EAGAIN || warning("tunnel endpoint read error: $!");
@@ -195,13 +215,16 @@ for (;;) {
 	    quit "tunnel endpoint closed by system";
 	}
 	while (($p= index($upbuf,"\300")) >= 0) {
-	    if (!defined(send L,substr($upbuf,0,$p),0,$rs)) {
+	    if ($p && !defined(send L,substr($upbuf,0,$p),0,$rs)) {
 		warning("transmit error: $!");
-	    } elsif (!$upyet) {
-		$upyet= 1;
-		debug($downyet ? "tunnel open at this end" : "transmit channel open");
+	    } else {
+		if (!$upyet) {
+		    $upyet= 1;
+		    debug($downyet ? "tunnel open at this end" : "transmitting");
+		}
+		if ($keepalive) { $nextsendka= now()+$keepalive; }
 	    }
-	    $upbuf= substr($upbuf+1,$p);
+	    $upbuf= substr($upbuf,$p+1);
 	}
     }
     while (defined($rs_from= recv L,$downbuf,$mtu*2+3,0)) {
@@ -210,6 +233,7 @@ for (;;) {
 	    warning("got packet from incorrect peer $rsp_from");
 	    next;
 	}
+	$downbuf= "\300".$downbuf."\300";
 	if (!defined($r= syswrite(DW,$downbuf,length $downbuf))) {
 	    warning("tunnel endpoint write error: $!");
 	} elsif ($r != length $downbuf) {
@@ -217,10 +241,11 @@ for (;;) {
 	} else {
 	    if (!$downyet) {
 		$downyet= 1;
-		debug($upyet ? "tunnel open at this end" : "receive channel open");
+		debug($upyet ? "tunnel open at this end" : "receiving");
 	    }
 	    alarm($timeout) if $timeout;
 	}
     }
+    if ($! == ECONNREFUSED) { quit("tunnel closed at remote end"); }
     $! == EAGAIN || warning("receive error: $!");
 }