From eaaab8850fddb8f8f70cecf485d9f8e839cc8886 Mon Sep 17 00:00:00 2001
From: MysterD <myster@d>
Date: Tue, 15 Sep 2020 22:45:17 -0700
Subject: [PATCH] Added exponential backoff to reliable packets

---
 src/pc/network/packets/packet_reliable.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/pc/network/packets/packet_reliable.c b/src/pc/network/packets/packet_reliable.c
index b80a4f77..285286a9 100644
--- a/src/pc/network/packets/packet_reliable.c
+++ b/src/pc/network/packets/packet_reliable.c
@@ -1,11 +1,14 @@
 #include <stdio.h>
 #include "../network.h"
+#include "pc/debuglog.h"
 
 #define RELIABLE_RESEND_RATE 0.10f
+#define MAX_RESEND_ATTEMPTS 20
 
 struct PacketLinkedList {
     struct Packet p;
     clock_t lastSend;
+    int sendAttempts;
     struct PacketLinkedList* prev;
     struct PacketLinkedList* next;
 };
@@ -65,6 +68,7 @@ void network_remember_reliable(struct Packet* p) {
     node->p = *p;
     node->p.sent = true;
     node->lastSend = clock();
+    node->sendAttempts = 1;
     node->prev = NULL;
     node->next = NULL;
 
@@ -87,10 +91,19 @@ void network_update_reliable(void) {
     struct PacketLinkedList* node = head;
     while (node != NULL) {
         float elapsed = (clock() - node->lastSend) / CLOCKS_PER_SEC;
-        if (elapsed > RELIABLE_RESEND_RATE) {
+        float maxElapsed = (node->sendAttempts * node->sendAttempts * RELIABLE_RESEND_RATE) / ((float)MAX_RESEND_ATTEMPTS);
+        if (elapsed > maxElapsed) {
             // resend
             network_send(&node->p);
             node->lastSend = clock();
+            node->sendAttempts++;
+            if (node->sendAttempts >= MAX_RESEND_ATTEMPTS) {
+                struct PacketLinkedList* next = node->next;
+                remove_node_from_list(node);
+                node = next;
+                LOG_ERROR("giving up on reliable packet");
+                continue;
+            }
         }
         node = node->next;
     }