From 7aa24f32dbbf14067ddb016c1fc43b72b04db06a Mon Sep 17 00:00:00 2001
From: Jay Satiro <raysatiro@yahoo.com>
Date: Wed, 17 Jan 2024 00:10:40 -0500
Subject: [PATCH] cf-socket: show errno in tcpkeepalive error messages

- If the socket keepalive options (TCP_KEEPIDLE, etc) cannot be set
  then show the errno in the verbose error messages.

Ref: https://github.com/curl/curl/discussions/12715#discussioncomment-8151652

Closes https://github.com/curl/curl/pull/12726
---
 lib/cf-socket.c | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/lib/cf-socket.c b/lib/cf-socket.c
index cfb98386d9..64af604ad3 100644
--- a/lib/cf-socket.c
+++ b/lib/cf-socket.c
@@ -163,8 +163,9 @@ tcpkeepalive(struct Curl_easy *data,
   /* only set IDLE and INTVL if setting KEEPALIVE is successful */
   if(setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE,
         (void *)&optval, sizeof(optval)) < 0) {
-    infof(data, "Failed to set SO_KEEPALIVE on fd %" CURL_FORMAT_SOCKET_T,
-          sockfd);
+    infof(data, "Failed to set SO_KEEPALIVE on fd "
+          "%" CURL_FORMAT_SOCKET_T ": errno %d",
+          sockfd, SOCKERRNO);
   }
   else {
 #if defined(SIO_KEEPALIVE_VALS)
@@ -180,8 +181,8 @@ tcpkeepalive(struct Curl_easy *data,
     if(WSAIoctl(sockfd, SIO_KEEPALIVE_VALS, (LPVOID) &vals, sizeof(vals),
                 NULL, 0, &dummy, NULL, NULL) != 0) {
       infof(data, "Failed to set SIO_KEEPALIVE_VALS on fd "
-                  "%" CURL_FORMAT_SOCKET_T ": %d",
-                  sockfd, WSAGetLastError());
+                  "%" CURL_FORMAT_SOCKET_T ": errno %d",
+                  sockfd, SOCKERRNO);
     }
 #else
 #ifdef TCP_KEEPIDLE
@@ -189,8 +190,9 @@ tcpkeepalive(struct Curl_easy *data,
     KEEPALIVE_FACTOR(optval);
     if(setsockopt(sockfd, IPPROTO_TCP, TCP_KEEPIDLE,
           (void *)&optval, sizeof(optval)) < 0) {
-      infof(data, "Failed to set TCP_KEEPIDLE on fd %" CURL_FORMAT_SOCKET_T,
-            sockfd);
+      infof(data, "Failed to set TCP_KEEPIDLE on fd "
+            "%" CURL_FORMAT_SOCKET_T ": errno %d",
+            sockfd, SOCKERRNO);
     }
 #elif defined(TCP_KEEPALIVE)
     /* Mac OS X style */
@@ -198,8 +200,9 @@ tcpkeepalive(struct Curl_easy *data,
     KEEPALIVE_FACTOR(optval);
     if(setsockopt(sockfd, IPPROTO_TCP, TCP_KEEPALIVE,
       (void *)&optval, sizeof(optval)) < 0) {
-      infof(data, "Failed to set TCP_KEEPALIVE on fd %" CURL_FORMAT_SOCKET_T,
-            sockfd);
+      infof(data, "Failed to set TCP_KEEPALIVE on fd "
+            "%" CURL_FORMAT_SOCKET_T ": errno %d",
+            sockfd, SOCKERRNO);
     }
 #endif
 #ifdef TCP_KEEPINTVL
@@ -207,8 +210,9 @@ tcpkeepalive(struct Curl_easy *data,
     KEEPALIVE_FACTOR(optval);
     if(setsockopt(sockfd, IPPROTO_TCP, TCP_KEEPINTVL,
           (void *)&optval, sizeof(optval)) < 0) {
-      infof(data, "Failed to set TCP_KEEPINTVL on fd %" CURL_FORMAT_SOCKET_T,
-            sockfd);
+      infof(data, "Failed to set TCP_KEEPINTVL on fd "
+            "%" CURL_FORMAT_SOCKET_T ": errno %d",
+            sockfd, SOCKERRNO);
     }
 #endif
 #endif
-- 
2.47.3