ns2: Add VTY option to change the max write queue size for UDP

Ensure that existing binds are updated as well.
In some cases the default max length of the osmo_io txqueue could be too
small. Set it to 128 by default and add a VTY option to change it for
an NSI (program-wide).

Change-Id: I993b87fd6b83b3981f5e293f70b931075afec715
Related: SYS#6550
diff --git a/src/gb/gprs_ns2.c b/src/gb/gprs_ns2.c
index 02d2266..4e496c1 100644
--- a/src/gb/gprs_ns2.c
+++ b/src/gb/gprs_ns2.c
@@ -1451,6 +1451,8 @@
 	nsi->timeout[NS_TOUT_TSNS_CONFIG_RETRIES] = 3;
 	nsi->timeout[NS_TOUT_TSNS_PROCEDURES_RETRIES] = 3;
 
+	nsi->txqueue_max_length = NS_DEFAULT_TXQUEUE_MAX_LENGTH;
+
 	return nsi;
 }
 
diff --git a/src/gb/gprs_ns2_internal.h b/src/gb/gprs_ns2_internal.h
index 37b142e..7ac77e5 100644
--- a/src/gb/gprs_ns2_internal.h
+++ b/src/gb/gprs_ns2_internal.h
@@ -80,6 +80,8 @@
 #define NS_ALLOC_SIZE	3072
 #define NS_ALLOC_HEADROOM 20
 
+#define NS_DEFAULT_TXQUEUE_MAX_LENGTH 128
+
 enum ns2_timeout {
 	NS_TOUT_TNS_BLOCK,
 	NS_TOUT_TNS_BLOCK_RETRIES,
@@ -164,6 +166,8 @@
 	/*! workaround for rate counter until rate counter accepts char str as index */
 	uint32_t nsvc_rate_ctr_idx;
 	uint32_t bind_rate_ctr_idx;
+
+	uint32_t txqueue_max_length;
 };
 
 
@@ -450,6 +454,7 @@
 struct gprs_ns2_vc_bind *ns2_ip_get_bind_by_index(struct gprs_ns2_inst *nsi,
 						  struct osmo_sockaddr *remote,
 						  int index);
+void ns2_ip_set_txqueue_max_length(struct gprs_ns2_vc_bind *bind, unsigned int max_length);
 
 /* sns */
 int ns2_sns_rx(struct gprs_ns2_vc *nsvc, struct msgb *msg, struct tlv_parsed *tp);
diff --git a/src/gb/gprs_ns2_udp.c b/src/gb/gprs_ns2_udp.c
index f24eae6..1dcc303 100644
--- a/src/gb/gprs_ns2_udp.c
+++ b/src/gb/gprs_ns2_udp.c
@@ -336,6 +336,7 @@
 	priv->iofd = osmo_iofd_setup(bind, rc, "NS bind", OSMO_IO_FD_MODE_RECVFROM_SENDTO, &ioops, bind);
 	osmo_iofd_register(priv->iofd, rc);
 	osmo_iofd_set_alloc_info(priv->iofd, 4096, 128);
+	osmo_iofd_set_txqueue_max_length(priv->iofd, nsi->txqueue_max_length);
 
 	/* IPv4: max fragmented payload can be (13 bit) * 8 byte => 65535.
 	 * IPv6: max payload can be 65535 (RFC 2460).
@@ -574,6 +575,14 @@
 	return NULL;
 }
 
+void ns2_ip_set_txqueue_max_length(struct gprs_ns2_vc_bind *bind, unsigned int max_length)
+{
+	struct priv_bind *priv = bind->priv;
+	OSMO_ASSERT(gprs_ns2_is_ip_bind(bind));
+
+	osmo_iofd_set_txqueue_max_length(priv->iofd, max_length);
+}
+
 /*! set the signalling and data weight for this bind
  * \param[in] bind
  * \param[in] signalling the signalling weight
diff --git a/src/gb/gprs_ns2_vty.c b/src/gb/gprs_ns2_vty.c
index 3046fff..3132e34 100644
--- a/src/gb/gprs_ns2_vty.c
+++ b/src/gb/gprs_ns2_vty.c
@@ -36,6 +36,7 @@
 #include <osmocom/core/fsm.h>
 #include <osmocom/core/linuxlist.h>
 #include <osmocom/core/msgb.h>
+#include <osmocom/core/osmo_io.h>
 #include <osmocom/core/rate_ctr.h>
 #include <osmocom/core/select.h>
 #include <osmocom/core/talloc.h>
@@ -595,6 +596,9 @@
 			get_value_string(gprs_ns_timer_strs, i),
 			vty_nsi->timeout[i], VTY_NEWLINE);
 
+	if (vty_nsi->txqueue_max_length != NS_DEFAULT_TXQUEUE_MAX_LENGTH)
+		vty_out(vty, " txqueue-max-length %u%s", vty_nsi->txqueue_max_length, VTY_NEWLINE);
+
 	ret = config_write_ns_bind(vty);
 	if (ret)
 		return ret;
@@ -1707,6 +1711,27 @@
 	return CMD_WARNING;
 }
 
+DEFUN(cfg_ns_txqueue_max_length, cfg_ns_txqueue_max_length_cmd,
+      "txqueue-max-length <1-4096>",
+      "Set the maximum length of the txqueue (for UDP)\n"
+      "Maximum length of the txqueue\n")
+{
+	struct gprs_ns2_vc_bind *bind;
+	uint32_t max_length = atoi(argv[0]);
+	vty_nsi->txqueue_max_length = max_length;
+
+
+	llist_for_each_entry(bind, &vty_nsi->binding, list) {
+		if (!gprs_ns2_is_ip_bind(bind))
+			continue;
+
+		ns2_ip_set_txqueue_max_length(bind, max_length);
+	}
+
+
+	return CMD_SUCCESS;
+}
+
 DEFUN(cfg_ns_nse_ip_sns_bind, cfg_ns_nse_ip_sns_bind_cmd,
       "ip-sns-bind BINDID",
       "IP SNS binds\n"
@@ -2292,6 +2317,8 @@
 	install_lib_element(L_NS_NODE, &cfg_ns_ip_sns_default_bind_cmd);
 	install_lib_element(L_NS_NODE, &cfg_no_ns_ip_sns_default_bind_cmd);
 
+	install_lib_element(L_NS_NODE, &cfg_ns_txqueue_max_length_cmd);
+
 	install_node(&ns_bind_node, NULL);
 	install_lib_element(L_NS_BIND_NODE, &cfg_ns_bind_listen_cmd);
 	install_lib_element(L_NS_BIND_NODE, &cfg_no_ns_bind_listen_cmd);