From 09161fbda0af6d06e453f1ea034481d26485ad2f Mon Sep 17 00:00:00 2001
From: jrd <gh26.x.jrd@xoxy.net>
Date: Sat, 28 Mar 2026 22:32:09 +0000
Subject: [PATCH 1/2] Retry UDP request on timeout before giving up

Replace the single 1.5s socket timeout with a 500ms timeout and up to
3 attempts. If no data is received within the window, the same request
is re-sent. This recovers from dropped UDP packets without increasing
the worst-case wait time beyond the original 1.5s.
---
 servers.php | 34 ++++++++++++++++++++++++++++------
 1 file changed, 28 insertions(+), 6 deletions(-)

diff --git a/servers.php b/servers.php
index 5a0d344..d0d261d 100644
--- a/servers.php
+++ b/servers.php
@@ -932,7 +932,8 @@ function process_received($sock, $data, $n, $fromip, $fromport) {
 	}
 }
 
-socket_set_option($sock, SOL_SOCKET, SO_RCVTIMEO, array('sec'=>1, 'usec'=>500000));
+$timeout_ms = 500;
+socket_set_option($sock, SOL_SOCKET, SO_RCVTIMEO, array('sec'=>0, 'usec'=>$timeout_ms * 1000));
 
 $name = isset($_GET['name']) ? $_GET['name'] : $host;
 
@@ -957,12 +958,28 @@ function process_received($sock, $data, $n, $fromip, $fromport) {
 // $maxgap = 0;
 // $last = gettimeofday(true);
 
-while (!$done && $n = socket_recvfrom($sock, $data, 32767, 0, $fromip, $fromport)) {
-	// printf("socket_recvfrom: %d bytes received from %s:%d\n", $n, $fromip, $fromport);
+$attempts = 1;
+$max_attempts = 3;
 
-	if ($n != strlen($data)) {
-		error_log("Returned data length does not match string from $fromip:$fromport");
-		continue;
+while (!$done) {
+	$n = socket_recvfrom($sock, $data, 32767, 0, $fromip, $fromport);
+
+	if ($n === false) {
+		if (count($servers) <= 1 && $attempts < $max_attempts) {
+			// Timeout with no data yet — re-send and try again
+			$attempts++;
+			if (isset($_GET['directory'])) {
+				send_request($sock, CLM_REQ_SERVER_LIST, $ip, $port);
+			} else {
+				send_ping_with_num_clients($sock, $ip, $port);
+			}
+			continue;
+		} elseif (count($servers) <= 1) {
+			error_log("servers.php: no response from $ip after $max_attempts attempts");
+			break;
+		} else {
+			break; // normal end-of-stream
+		}
 	}
 
 	// $now = gettimeofday(true);
@@ -970,6 +987,11 @@ function process_received($sock, $data, $n, $fromip, $fromport) {
 	// if ($now - $last > $maxgap) $maxgap = $now - $last;
 	// $last = $now;
 
+	if ($n != strlen($data)) {
+		error_log("Returned data length does not match string from $fromip:$fromport");
+		continue;
+	}
+
 	process_received($sock, $data, $n, $fromip, $fromport);
 }
 

From c5040670daf6e51d890160f8bd7745fc05d440bc Mon Sep 17 00:00:00 2001
From: jrd <gh26.x.jrd@xoxy.net>
Date: Tue, 31 Mar 2026 05:38:12 +0000
Subject: [PATCH 2/2] Fix retry condition to use $received_data flag instead of
 count($servers)

The original count($servers) <= 1 heuristic fails for directory servers
that legitimately have only one registered server: data is received
successfully but the trailing timeout still triggers an unnecessary retry,
adding ~500ms latency. Using an explicit $received_data flag correctly
distinguishes "no response at all" (retry) from "stream ended normally"
(stop).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 servers.php | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/servers.php b/servers.php
index d0d261d..584966e 100644
--- a/servers.php
+++ b/servers.php
@@ -960,12 +960,13 @@ function process_received($sock, $data, $n, $fromip, $fromport) {
 
 $attempts = 1;
 $max_attempts = 3;
+$received_data = false;
 
 while (!$done) {
 	$n = socket_recvfrom($sock, $data, 32767, 0, $fromip, $fromport);
 
 	if ($n === false) {
-		if (count($servers) <= 1 && $attempts < $max_attempts) {
+		if (!$received_data && $attempts < $max_attempts) {
 			// Timeout with no data yet — re-send and try again
 			$attempts++;
 			if (isset($_GET['directory'])) {
@@ -974,7 +975,7 @@ function process_received($sock, $data, $n, $fromip, $fromport) {
 				send_ping_with_num_clients($sock, $ip, $port);
 			}
 			continue;
-		} elseif (count($servers) <= 1) {
+		} elseif (!$received_data) {
 			error_log("servers.php: no response from $ip after $max_attempts attempts");
 			break;
 		} else {
@@ -992,6 +993,7 @@ function process_received($sock, $data, $n, $fromip, $fromport) {
 		continue;
 	}
 
+	$received_data = true;
 	process_received($sock, $data, $n, $fromip, $fromport);
 }