ip fou: Support binding FOU ports

This patch adds support for binding FOU ports using iproute2.
Kernel-support was added in 1713cb37bf67 ("fou: Support binding FoU
socket").

The parse function now handles new arguments for setting the
binding-related attributes, while the print function writes the new
attributes if they are set. Also, the man page has been updated.

v2->v3:
* Remove redundant ll_init_map()-calls (thanks David Ahern).

v1->v2 (all changes suggested by David Ahern):
* Fix reverse Christmas tree ordering.
* Remove redundant peer_port_set-variable, it is enough to check
peer_port.
* Add proper error handling of invalid local/peer addresses.
* Use interface name and not index.
* Remove updating fou-header file, it is already done.

Signed-off-by: Kristian Evensen <kristian.evensen@gmail.com>
Signed-off-by: David Ahern <dsahern@gmail.com>

ip/ipfou.c

@@ -28,11 +28,16 @@ static void usage(void)
 {
 	fprintf(stderr,
 		"Usage: ip fou add port PORT { ipproto PROTO  | gue } [ -6 ]\n"
-		"       ip fou del port PORT [ -6 ]\n"
+		"		   [ local IFADDR ] [ peer IFADDR ]\n"
+		"		   [ peer_port PORT ] [ dev IFNAME ]\n"
+		"       ip fou del port PORT [ -6 ] [ local IFADDR ]\n"
+		"		   [ peer IFADDR ] [ peer_port PORT ]\n"
+		"		   [ dev IFNAME ]\n"
 		"       ip fou show\n"
 		"\n"
 		"Where: PROTO { ipproto-name | 1..255 }\n"
-		"       PORT { 1..65535 }\n");
+		"       PORT { 1..65535 }\n"
+		"       IFADDR { addr }\n");
 
 	exit(-1);
 }
@@ -48,12 +53,14 @@ static int genl_family = -1;
 static int fou_parse_opt(int argc, char **argv, struct nlmsghdr *n,
 			 bool adding)
 {
-	__u16 port;
+	const char *local = NULL, *peer = NULL;
-	int port_set = 0;
+	__u16 port, peer_port = 0;
-	__u8 ipproto, type;
+	__u8 family = AF_INET;
 	bool gue_set = false;
 	int ipproto_set = 0;
-	__u8 family = AF_INET;
+	__u8 ipproto, type;
+	int port_set = 0;
+	int index = 0;
 
 	while (argc > 0) {
 		if (!matches(*argv, "port")) {
@@ -77,6 +84,37 @@ static int fou_parse_opt(int argc, char **argv, struct nlmsghdr *n,
 			gue_set = true;
 		} else if (!matches(*argv, "-6")) {
 			family = AF_INET6;
+		} else if (!matches(*argv, "local")) {
+			NEXT_ARG();
+
+			local = *argv;
+		} else if (!matches(*argv, "peer")) {
+			NEXT_ARG();
+
+			peer = *argv;
+		} else if (!matches(*argv, "peer_port")) {
+			NEXT_ARG();
+
+			if (get_be16(&peer_port, *argv, 0) || peer_port == 0)
+				invarg("invalid peer port", *argv);
+		} else if (!matches(*argv, "dev")) {
+			const char *ifname;
+
+			NEXT_ARG();
+
+			ifname = *argv;
+
+			if (check_ifname(ifname)) {
+				fprintf(stderr, "fou: invalid device name\n");
+				exit(EXIT_FAILURE);
+			}
+
+			index = ll_name_to_index(ifname);
+
+			if (!index) {
+				fprintf(stderr, "fou: unknown device name\n");
+				exit(EXIT_FAILURE);
+			}
 		} else {
 			fprintf(stderr
 				, "fou: unknown command \"%s\"?\n", *argv);
@@ -101,6 +139,11 @@ static int fou_parse_opt(int argc, char **argv, struct nlmsghdr *n,
 		return -1;
 	}
 
+	if ((peer_port && !peer) || (peer && !peer_port)) {
+		fprintf(stderr, "fou: both peer and peer port must be set\n");
+		return -1;
+	}
+
 	type = gue_set ? FOU_ENCAP_GUE : FOU_ENCAP_DIRECT;
 
 	addattr16(n, 1024, FOU_ATTR_PORT, port);
@@ -110,6 +153,38 @@ static int fou_parse_opt(int argc, char **argv, struct nlmsghdr *n,
 	if (ipproto_set)
 		addattr8(n, 1024, FOU_ATTR_IPPROTO, ipproto);
 
+	if (local) {
+		inet_prefix local_addr;
+		__u8 attr_type = family == AF_INET ? FOU_ATTR_LOCAL_V4 :
+						     FOU_ATTR_LOCAL_V6;
+
+		if (get_addr(&local_addr, local, family)) {
+			fprintf(stderr, "fou: parsing local address failed\n");
+			exit(EXIT_FAILURE);
+		}
+		addattr_l(n, 1024, attr_type, &local_addr.data,
+			  local_addr.bytelen);
+	}
+
+	if (peer) {
+		inet_prefix peer_addr;
+		__u8 attr_type = family == AF_INET ? FOU_ATTR_PEER_V4 :
+						     FOU_ATTR_PEER_V6;
+
+		if (get_addr(&peer_addr, peer, family)) {
+			fprintf(stderr, "fou: parsing peer address failed\n");
+			exit(EXIT_FAILURE);
+		}
+		addattr_l(n, 1024, attr_type, &peer_addr.data,
+			  peer_addr.bytelen);
+
+		if (peer_port)
+			addattr16(n, 1024, FOU_ATTR_PEER_PORT, peer_port);
+	}
+
+	if (index)
+		addattr32(n, 1024, FOU_ATTR_IFINDEX, index);
+
 	return 0;
 }
 
@@ -139,8 +214,10 @@ static int do_del(int argc, char **argv)
 
 static int print_fou_mapping(struct nlmsghdr *n, void *arg)
 {
-	struct genlmsghdr *ghdr;
+	__u8 family = AF_INET, local_attr_type, peer_attr_type, byte_len;
 	struct rtattr *tb[FOU_ATTR_MAX + 1];
+	__u8 empty_buf[16] = {0};
+	struct genlmsghdr *ghdr;
 	int len = n->nlmsg_len;
 
 	if (n->nlmsg_type != genl_family)
@@ -166,7 +243,7 @@ static int print_fou_mapping(struct nlmsghdr *n, void *arg)
 			   " ipproto %u", rta_getattr_u8(tb[FOU_ATTR_IPPROTO]));
 
 	if (tb[FOU_ATTR_AF]) {
-		__u8 family = rta_getattr_u8(tb[FOU_ATTR_AF]);
+		family = rta_getattr_u8(tb[FOU_ATTR_AF]);
 
 		print_string(PRINT_JSON, "family", NULL,
 			     family_name(family));
@@ -175,6 +252,48 @@ static int print_fou_mapping(struct nlmsghdr *n, void *arg)
 			print_string(PRINT_FP, NULL,
 				     " -6", NULL);
 	}
+
+	local_attr_type = family == AF_INET ? FOU_ATTR_LOCAL_V4 :
+					      FOU_ATTR_LOCAL_V6;
+	peer_attr_type = family == AF_INET ? FOU_ATTR_PEER_V4 :
+					     FOU_ATTR_PEER_V6;
+	byte_len = af_bit_len(family) / 8;
+
+	if (tb[local_attr_type] && memcmp(RTA_DATA(tb[local_attr_type]),
+					  empty_buf, byte_len)) {
+		print_string(PRINT_ANY, "local", " local %s",
+			     format_host_rta(family, tb[local_attr_type]));
+	}
+
+	if (tb[peer_attr_type] && memcmp(RTA_DATA(tb[peer_attr_type]),
+					 empty_buf, byte_len)) {
+		print_string(PRINT_ANY, "peer", " peer %s",
+			     format_host_rta(family, tb[peer_attr_type]));
+	}
+
+	if (tb[FOU_ATTR_PEER_PORT]) {
+		__u16 p_port = ntohs(rta_getattr_u16(tb[FOU_ATTR_PEER_PORT]));
+
+		if (p_port)
+			print_uint(PRINT_ANY, "peer_port", " peer_port %u",
+				   p_port);
+
+	}
+
+	if (tb[FOU_ATTR_IFINDEX]) {
+		int index = rta_getattr_s32(tb[FOU_ATTR_IFINDEX]);
+
+		if (index) {
+			const char *ifname;
+
+			ifname = ll_index_to_name(index);
+
+			if (ifname)
+				print_string(PRINT_ANY, "dev", " dev %s",
+					     ifname);
+		}
+	}
+
 	print_string(PRINT_FP, NULL, "\n", NULL);
 	close_json_object();
 

man/man8/ip-fou.8

@@ -24,11 +24,43 @@ ip-gue \- Generic UDP Encapsulation receive port configuration
 .B ipproto
 .IR PROTO
 .RB " }"
+.RB "[ "
+.B local
+.IR IFADDR
+.RB " ]"
+.RB "[ "
+.B peer
+.IR IFADDR
+.RB " ]"
+.RB "[ "
+.B peer_port
+.IR PORT
+.RB " ]"
+.RB "[ "
+.B dev
+.IR IFNAME
+.RB " ]"
 .br
 .ti -8
 .BR "ip fou del"
 .B port
 .IR PORT
+.RB "[ "
+.B local
+.IR IFADDR
+.RB " ]"
+.RB "[ "
+.B peer
+.IR IFADDR
+.RB " ]"
+.RB "[ "
+.B peer_port
+.IR PORT
+.RB " ]"
+.RB "[ "
+.B dev
+.IR IFNAME
+.RB " ]"
 .br
 .ti -8
 .B ip fou show
@@ -50,11 +82,22 @@ When creating a FOU or GUE receive port, the port number is specified in
 .I PORT
 argument. If FOU is used, the IP protocol number associated with the port is specified in
 .I PROTO
+argument. You can bind a port to a local address/interface, by specifying the
+address in the local
+.I IFADDR
+argument or the device in the
+.I IFNAME
+argument. If you would like to connect the port, you can specify the peer
+address in the peer
+.I IFADDR
+argument and peer port in the peer_port
+.I PORT
 argument.
 .PP
 A FOU or GUE receive port is deleted by specifying
 .I PORT
-in the delete command.
+in the delete command, as well as local address/interface or peer address/port
+(if set).
 .SH EXAMPLES
 .PP
 .SS Configure a FOU receive port for GRE bound to 7777
@@ -72,6 +115,10 @@ in the delete command.
 .SS Delete the GUE receive port bound to 9999
 .nf
 # ip fou del port 9999
+.SS Configure a FOU receive port for GRE bound to 1.2.3.4:7777
+.nf
+# ip fou add port 7777 ipproto 47 local 1.2.3.4
+.PP
 .SH SEE ALSO
 .br
 .BR ip (8)