Add new option (-target_addr) to control how to deal with incoming packets

not associated with any pre-existing link.

Submitted by:	brian

2 files changed, 34 insertions, 1 deletions

diff --git a/sbin/natd/natd.8 b/sbin/natd/natd.8
index b6cedee..be1ac6f 100644
--- a/sbin/natd/natd.8
+++ b/sbin/natd/natd.8
@@ -15,6 +15,7 @@ Network Address Translation Daemon
 .Op Fl o Ar outport
 .Op Fl p Ar port
 .Op Fl a Ar address
+.Op Fl t Ar address
 .Op Fl n Ar interface
 .Op Fl f Ar configfile
 
@@ -32,6 +33,7 @@ Network Address Translation Daemon
 .Op Fl outport Ar outport
 .Op Fl port Ar port
 .Op Fl alias_address Ar address
+.Op Fl target_address Ar address
 .Op Fl interface Ar interface
 .Op Fl config Ar configfile
 .Op Fl redirect_port Ar linkspec
@@ -291,7 +293,25 @@ and if
 .Fl deny_incoming
 is not specified, the packet is delivered to the local machine and port
 as specified in the packet.
-
+.It Fl t | target_address Ar address
+Set the target address.
+When an incoming packet not associated with any pre-existing link
+arrives at the host machine, it will be sent to the specified
+.Ar address .
+.Pp
+The target address may be set to
+.Dq 255.255.255.255 ,
+in which case all new incoming packets go to the alias address set by
+.Fl alias_address
+or
+.Fl interface .
+.Pp
+If this option is not used, or called with
+.Dq 0.0.0.0
+argument, then all new incoming packets go to the address specified in
+the packet.
+This allows external machines to talk directly to internal machines if
+they can route packets to the machine in question.
 .It Fl n | interface Ar interface
 Use
 .Ar interface
diff --git a/sbin/natd/natd.c b/sbin/natd/natd.c
index 6bb3584..a465ce2 100644
--- a/sbin/natd/natd.c
+++ b/sbin/natd/natd.c
@@ -860,6 +860,7 @@ enum Option {
 	OutPort,
 	Port,
 	AliasAddress,
+	TargetAddress,
 	InterfaceName,
 	RedirectPort,
 	RedirectProto,
@@ -1007,6 +1008,14 @@ static struct OptionInfo optionTable[] = {
 		"alias_address",
 		"a" },
 	
+	{ TargetAddress,
+		0,
+		Address,
+		"x.x.x.x",
+		"address to use for incoming sessions",
+		"target_address",
+		"t" },
+	
 	{ InterfaceName,
 		0,
 		String,
@@ -1206,6 +1215,10 @@ static void ParseOption (const char* option, const char* parms, int cmdLine)
 		memcpy (&aliasAddr, &addrValue, sizeof (struct in_addr));
 		break;
 
+	case TargetAddress:
+		PacketAliasSetTarget(addrValue);
+		break;
+
 	case RedirectPort:
 		SetupPortRedirect (strValue);
 		break;