From c847e3da86ca56305cf1f3c06989c23cb23b0ce4 Mon Sep 17 00:00:00 2001
From: hg <4683435+hgtw@users.noreply.github.com>
Date: Wed, 27 Jul 2022 09:52:25 -0400
Subject: [PATCH] [Netcode] Adjust first packet for compress flag (#2326)

When a packet was over max_raw_size and zlib failed to compress the
first packet chunk then the final output would be 513 bytes which
exceeded m_max_packet_size of 512.

This occured because the first packet chunk used sublen without
adjusting for the new_length + 1 compression flag added in Compress().
When the packet failed to compress then it was already at its max.
After the first packet, chunk sizes are calculated using max_raw_size
which already accounted for the compress flag. (From #979)

This should fix #2325
---
 common/net/daybreak_connection.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/common/net/daybreak_connection.cpp b/common/net/daybreak_connection.cpp
index 125a240dd..641f482ac 100644
--- a/common/net/daybreak_connection.cpp
+++ b/common/net/daybreak_connection.cpp
@@ -1394,7 +1394,7 @@ void EQ::Net::DaybreakConnection::InternalQueuePacket(Packet &p, int stream_id,
 		first_header.total_size = (uint32_t)HostToNetwork((uint32_t)length);
 
 		size_t used = 0;
-		size_t sublen = m_max_packet_size - m_crc_bytes - DaybreakReliableFragmentHeader::size();
+		size_t sublen = m_max_packet_size - m_crc_bytes - DaybreakReliableFragmentHeader::size() - 1; // -1 for compress flag
 		DynamicPacket first_packet;
 		first_packet.PutSerialize(0, first_header);
 		first_packet.PutData(DaybreakReliableFragmentHeader::size(), (char*)p.Data() + used, sublen);