From 70bf0cbe84abe430a9f50aed999dd32d215f0d45 Mon Sep 17 00:00:00 2001
From: Johannes Schlatow <johannes.schlatow@genode-labs.com>
Date: Wed, 9 Feb 2022 17:14:32 +0100
Subject: [PATCH] vfs/lwip: add missing signal handlers

Note, without batching from the Nic server this may slow down the
throughput a bit.

genodelabs/genode#4427
---
 repos/libports/include/lwip/nic_netif.h | 21 ++++++++++++++++++++-
 repos/libports/src/lib/vfs/lwip/vfs.cc  | 12 ++++++++++--
 2 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/repos/libports/include/lwip/nic_netif.h b/repos/libports/include/lwip/nic_netif.h
index 167abecb3f..004ad00a55 100644
--- a/repos/libports/include/lwip/nic_netif.h
+++ b/repos/libports/include/lwip/nic_netif.h
@@ -95,6 +95,7 @@ class Lwip::Nic_netif
 
 		Genode::Io_signal_handler<Nic_netif> _link_state_handler;
 		Genode::Io_signal_handler<Nic_netif> _rx_packet_handler;
+		Genode::Io_signal_handler<Nic_netif> _tx_ready_handler;
 
 		bool _dhcp { false };
 
@@ -167,6 +168,21 @@ class Lwip::Nic_netif
 			}
 		}
 
+		/**
+		 * Handle tx ack_avail and ready_to_submit signals
+		 */
+		void handle_tx_ready()
+		{
+			auto &tx = *_nic.tx();
+
+			/* flush acknowledgements */
+			while (tx.ack_avail())
+				tx.release_packet(tx.get_acked_packet());
+
+			/* notify subclass to resume pending transmissions */
+			status_callback();
+		}
+
 		void configure(Genode::Xml_node const &config)
 		{
 			_dhcp = config.attribute_value("dhcp", false);
@@ -232,7 +248,8 @@ class Lwip::Nic_netif
 			     BUF_SIZE, BUF_SIZE,
 			     config.attribute_value("label", Genode::String<160>("lwip")).string()),
 			_link_state_handler(env.ep(), *this, &Nic_netif::handle_link_state),
-			_rx_packet_handler( env.ep(), *this, &Nic_netif::handle_rx_packets)
+			_rx_packet_handler( env.ep(), *this, &Nic_netif::handle_rx_packets),
+			_tx_ready_handler(  env.ep(), *this, &Nic_netif::handle_tx_ready)
 		{
 			Genode::memset(&_netif, 0x00, sizeof(_netif));
 
@@ -307,6 +324,8 @@ class Lwip::Nic_netif
 			_nic.link_state_sigh(_link_state_handler);
 			_nic.rx_channel()->sigh_packet_avail(_rx_packet_handler);
 			_nic.rx_channel()->sigh_ready_to_ack(_rx_packet_handler);
+			_nic.tx_channel()->sigh_ready_to_submit(_tx_ready_handler);
+			_nic.tx_channel()->sigh_ack_avail      (_tx_ready_handler);
 
 			return ERR_OK;
 		}
diff --git a/repos/libports/src/lib/vfs/lwip/vfs.cc b/repos/libports/src/lib/vfs/lwip/vfs.cc
index e0721cbb89..c3b592d49c 100644
--- a/repos/libports/src/lib/vfs/lwip/vfs.cc
+++ b/repos/libports/src/lib/vfs/lwip/vfs.cc
@@ -1006,7 +1006,9 @@ class Lwip::Udp_socket_dir final :
 
 					err_t err = udp_sendto(_pcb, buf, &_to_addr, _to_port);
 					pbuf_free(buf);
-					if (err != ERR_OK)
+					if (err == ERR_WOULDBLOCK)
+						return Write_result::WRITE_ERR_WOULD_BLOCK;
+					else if (err != ERR_OK)
 						return Write_result::WRITE_ERR_IO;
 					remain -= buf->tot_len;
 					src += buf->tot_len;
@@ -1496,7 +1498,13 @@ class Lwip::Tcp_socket_dir final :
 					}
 
 					/* send queued data */
-					if (out > 0) tcp_output(_pcb);
+					if (out > 0) {
+						err_t err = tcp_output(_pcb);
+						if (err == ERR_WOULDBLOCK)
+							return Write_result::WRITE_ERR_WOULD_BLOCK;
+						else if (err != ERR_OK)
+							return Write_result::WRITE_ERR_IO;
+					}
 
 					out_count = out;
 					return res;