From 057122e466f2420244502f9b069df8f51f8363fd Mon Sep 17 00:00:00 2001
From: Harald Welte <laforge@osmocom.org>
Date: Sat, 6 Jun 2020 22:04:20 +0200
Subject: NS: Optionally disable NS-{RESET,BLOCK,UNBLOCK} when using UDP/IP

3GPP TS 48.016 is quite clear in that no NS-{RESET,BLOCK,UNBLOCK}
procedures shall be used over an IP based transport.  They are only
for use in Frame Relay based transport.

However, as libosmogb was first developed against ip.access nanoBTS,
and their Gb implementation mandates those procedures, we
unconditionally implemented those procedures back then.  Let's
give the user the option of disabling this behavior to become
more spec compliant (and interoperate with more other vendors out
there).

Change-Id: Ic4eba1b4dcbeac00f5879db295e0a9f1a50f71d8
---
 src/gb/gprs_ns_vty.c | 62 +++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 42 insertions(+), 20 deletions(-)

(limited to 'src/gb/gprs_ns_vty.c')

diff --git a/src/gb/gprs_ns_vty.c b/src/gb/gprs_ns_vty.c
index 9cffb71d..bd53f2f1 100644
--- a/src/gb/gprs_ns_vty.c
+++ b/src/gb/gprs_ns_vty.c
@@ -90,6 +90,32 @@ static int config_write_ns(struct vty *vty)
 
 	vty_out(vty, "ns%s", VTY_NEWLINE);
 
+	/* global configuration must be written first, as some of it may be
+	 * relevant when creating the NSE/NSVC later below */
+
+	if (vty_nsi->nsip.local_ip) {
+		ia.s_addr = osmo_htonl(vty_nsi->nsip.local_ip);
+		vty_out(vty, " encapsulation udp local-ip %s%s",
+			inet_ntoa(ia), VTY_NEWLINE);
+	}
+	if (vty_nsi->nsip.local_port)
+		vty_out(vty, " encapsulation udp local-port %u%s",
+			vty_nsi->nsip.local_port, VTY_NEWLINE);
+	if (vty_nsi->nsip.dscp)
+		vty_out(vty, " encapsulation udp dscp %d%s",
+			vty_nsi->nsip.dscp, VTY_NEWLINE);
+
+	vty_out(vty, " encapsulation udp use-reset-block-unblock %s%s",
+		vty_nsi->nsip.use_reset_block_unblock ? "enabled" : "disabled", VTY_NEWLINE);
+
+	vty_out(vty, " encapsulation framerelay-gre enabled %u%s",
+		vty_nsi->frgre.enabled ? 1 : 0, VTY_NEWLINE);
+	if (vty_nsi->frgre.local_ip) {
+		ia.s_addr = osmo_htonl(vty_nsi->frgre.local_ip);
+		vty_out(vty, " encapsulation framerelay-gre local-ip %s%s",
+			inet_ntoa(ia), VTY_NEWLINE);
+	}
+
 	llist_for_each_entry(nsvc, &vty_nsi->gprs_nsvcs, list) {
 		if (!nsvc->persistent)
 			continue;
@@ -130,26 +156,6 @@ static int config_write_ns(struct vty *vty)
 			get_value_string(gprs_ns_timer_strs, i),
 			vty_nsi->timeout[i], VTY_NEWLINE);
 
-	if (vty_nsi->nsip.local_ip) {
-		ia.s_addr = osmo_htonl(vty_nsi->nsip.local_ip);
-		vty_out(vty, " encapsulation udp local-ip %s%s",
-			inet_ntoa(ia), VTY_NEWLINE);
-	}
-	if (vty_nsi->nsip.local_port)
-		vty_out(vty, " encapsulation udp local-port %u%s",
-			vty_nsi->nsip.local_port, VTY_NEWLINE);
-	if (vty_nsi->nsip.dscp)
-		vty_out(vty, " encapsulation udp dscp %d%s",
-			vty_nsi->nsip.dscp, VTY_NEWLINE);
-
-	vty_out(vty, " encapsulation framerelay-gre enabled %u%s",
-		vty_nsi->frgre.enabled ? 1 : 0, VTY_NEWLINE);
-	if (vty_nsi->frgre.local_ip) {
-		ia.s_addr = osmo_htonl(vty_nsi->frgre.local_ip);
-		vty_out(vty, " encapsulation framerelay-gre local-ip %s%s",
-			inet_ntoa(ia), VTY_NEWLINE);
-	}
-
 	return CMD_SUCCESS;
 }
 
@@ -500,6 +506,21 @@ DEFUN(cfg_nsip_dscp, cfg_nsip_dscp_cmd,
 	return CMD_SUCCESS;
 }
 
+DEFUN(cfg_nsip_res_block_unblock, cfg_nsip_res_block_unblock_cmd,
+	"encapsulation udp use-reset-block-unblock (enabled|disabled)",
+	ENCAPS_STR "NS over UDP Encapsulation\n"
+	"Use NS-{RESET,BLOCK,UNBLOCK} procedures in violation of 3GPP TS 48.016\n"
+	"Enable NS-{RESET,BLOCK,UNBLOCK}\n"
+	"Disable NS-{RESET,BLOCK,UNBLOCK}\n")
+{
+	if (!strcmp(argv[0], "enabled"))
+		vty_nsi->nsip.use_reset_block_unblock = true;
+	else
+		vty_nsi->nsip.use_reset_block_unblock = false;
+
+	return CMD_SUCCESS;
+}
+
 DEFUN(cfg_frgre_local_ip, cfg_frgre_local_ip_cmd,
       "encapsulation framerelay-gre local-ip A.B.C.D",
 	ENCAPS_STR "NS over Frame Relay over GRE Encapsulation\n"
@@ -643,6 +664,7 @@ int gprs_ns_vty_init(struct gprs_ns_inst *nsi)
 	install_element(L_NS_NODE, &cfg_nsip_local_ip_cmd);
 	install_element(L_NS_NODE, &cfg_nsip_local_port_cmd);
 	install_element(L_NS_NODE, &cfg_nsip_dscp_cmd);
+	install_element(L_NS_NODE, &cfg_nsip_res_block_unblock_cmd);
 	install_element(L_NS_NODE, &cfg_frgre_enable_cmd);
 	install_element(L_NS_NODE, &cfg_frgre_local_ip_cmd);
 
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