From 8234d064a89f929cd9a06cf8ef44dcdcbfc8cb84 Mon Sep 17 00:00:00 2001
From: Dan Walters <8643018+sretlawd@users.noreply.github.com>
Date: Tue, 26 Oct 2021 20:59:31 -0500
Subject: [PATCH] fix: apply optional peer socket TOS to UDP sockets (#1043)

This effectively makes the TOS setting apply to uTP and DHT traffic.

Co-authored-by: Charles Kerr <charles@charleskerr.com>
---
 libtransmission/session.cc |  2 ++
 libtransmission/tr-udp.cc  | 20 ++++++++++++++++++++
 libtransmission/tr-udp.h   |  1 +
 3 files changed, 23 insertions(+)

diff --git a/libtransmission/session.cc b/libtransmission/session.cc
index 6375acb97..9812bca55 100644
--- a/libtransmission/session.cc
+++ b/libtransmission/session.cc
@@ -2250,6 +2250,8 @@ static void toggle_utp(void* vsession)
 
     tr_udpSetSocketBuffers(session);
 
+    tr_udpSetSocketTOS(session);
+
     /* But don't call tr_utpClose -- see reset_timer in tr-utp.c for an
        explanation. */
 }
diff --git a/libtransmission/tr-udp.cc b/libtransmission/tr-udp.cc
index 4e1f8d738..0bb3c4970 100644
--- a/libtransmission/tr-udp.cc
+++ b/libtransmission/tr-udp.cc
@@ -124,6 +124,24 @@ void tr_udpSetSocketBuffers(tr_session* session)
     }
 }
 
+void tr_udpSetSocketTOS(tr_session* session)
+{
+    if (session->peerSocketTOS == 0)
+    {
+        return;
+    }
+
+    if (session->udp_socket != TR_BAD_SOCKET)
+    {
+        tr_netSetTOS(session->udp_socket, session->peerSocketTOS, TR_AF_INET);
+    }
+
+    if (session->udp6_socket != TR_BAD_SOCKET)
+    {
+        tr_netSetTOS(session->udp6_socket, session->peerSocketTOS, TR_AF_INET6);
+    }
+}
+
 /* BEP-32 has a rather nice explanation of why we need to bind to one
    IPv6 address, if I may say so myself. */
 // TODO: remove goto, it prevents reducing scope of local variables
@@ -359,6 +377,8 @@ void tr_udpInit(tr_session* ss)
 
     tr_udpSetSocketBuffers(ss);
 
+    tr_udpSetSocketTOS(ss);
+
     if (ss->isDHTEnabled)
     {
         tr_dhtInit(ss);
diff --git a/libtransmission/tr-udp.h b/libtransmission/tr-udp.h
index d29862b04..eb037fde5 100644
--- a/libtransmission/tr-udp.h
+++ b/libtransmission/tr-udp.h
@@ -30,5 +30,6 @@ THE SOFTWARE.
 void tr_udpInit(tr_session*);
 void tr_udpUninit(tr_session*);
 void tr_udpSetSocketBuffers(tr_session*);
+void tr_udpSetSocketTOS(tr_session*);
 
 bool tau_handle_message(tr_session* session, uint8_t const* msg, size_t msglen);