From ff8fc7a654582cfc16d6c12a0432946bbbebbf50 Mon Sep 17 00:00:00 2001
From: xshxdex98 <xshxde98x@gmail.com>
Date: Sun, 4 Oct 2026 03:01:48 -0500
Subject: [PATCH] Network: log the Winsock error behind a failed send; the
 connect wait's select

A send that fails with an error the transport doesn't name became endpoint_io with nothing to say why (a first join to a host that then failed). The error is logged now, once for each. The connect wait treats a select that times out as still connecting, and sets its timeout each time (select may leave what is left of it).

(cherry picked from commit 5b02133ce00edcb7d9fd788db459a77cd98e9ac4)
---
 .../network/transport_endpoint_winsock.c      | 30 ++++++++++++++-----
 1 file changed, 23 insertions(+), 7 deletions(-)

diff --git a/source/bungie_net/network/transport_endpoint_winsock.c b/source/bungie_net/network/transport_endpoint_winsock.c
index c87e71ab..a95816ef 100644
--- a/source/bungie_net/network/transport_endpoint_winsock.c
+++ b/source/bungie_net/network/transport_endpoint_winsock.c
@@ -525,7 +525,17 @@ long write_endpoint(
 	result = send(ep->socket, buffer, length, 0);
 	if (result == INVALID_SOCKET)
 	{
-		switch (WSAGetLastError())
+		/* port: the Winsock error a send failed with, which the transport's
+		errors don't say (logged once for each different one) */
+		static int logged_error;
+		int code = WSAGetLastError();
+
+		if (code != 0x2733 && code != logged_error)
+		{
+			error(_error_silent, "write_endpoint: Winsock error %d", code);
+			logged_error = code;
+		}
+		switch (code)
 		{
 		case 0x2733:
 			ep->error = _transport_result_operation_would_block;
@@ -1224,25 +1234,31 @@ short connect_endpoint(
 				unsigned long timeout = system_milliseconds() + 10 * MILLISECONDS_PER_SECOND;
 				struct timeval timeval;
 
-				timeval.tv_sec = 1;
-				timeval.tv_usec = 0;
-
 				do
 				{
 					fd_set writeable;
 					fd_set failed;
+					long ready;
 
+					/* (set each time: select may leave what is left of it) */
+					timeval.tv_sec = 1;
+					timeval.tv_usec = 0;
 					writeable.fd_array[0] = ep->socket;
 					writeable.fd_count = 1;
 					failed.fd_array[0] = ep->socket;
 					failed.fd_count = 1;
 
-					/* port: a connect that failed is in the error set (not
-					writeable, and its would-block left as it was) */
-					if (select(1, NULL, &writeable, &failed, &timeval) > 0)
+					/* port: a failed connect is in the error set, and a select
+					that times out (0) means the connection is still being made */
+					ready = select(1, NULL, &writeable, &failed, &timeval);
+					if (ready > 0)
 					{
 						error = failed.fd_count ? WSAECONNREFUSED : 0;
 					}
+					else if (ready == 0)
+					{
+						error = WSAEWOULDBLOCK;
+					}
 					else
 					{
 						error = WSAGetLastError();