From 9de61aa69eb808d6fba84c9664dd8b5d6a15d6c8 Mon Sep 17 00:00:00 2001
From: duB <jdube@haivision.com>
Date: Tue, 10 Jul 2018 12:55:40 -0400
Subject: [PATCH] Fix IP options (TTL and ToS) on IPv6 sockets (#423)

* set IPv6_UNICAST_HOPS when setting SRTO_IPTTL on IPv6 socket
set IPV6_TCLASS when setting SRTO_TOS on IPv6 socket
---
 docs/API.md         |  6 +++--
 srtcore/channel.cpp | 55 ++++++++++++++++++++++++++++++++++++---------
 2 files changed, 48 insertions(+), 13 deletions(-)

diff --git a/docs/API.md b/docs/API.md
index 5a9a9417d..fc0c6ebbc 100644
--- a/docs/API.md
+++ b/docs/API.md
@@ -446,7 +446,8 @@ inside the library.
 | --------------------- | ----- | ------- | --------- | ------ | ------------------ | ------ |
 | `SRTO_IPTOS`          | 1.0.5 | pre     | `int32_t` |        | (platform default) | 0..255 |
 
-- IP Type of Service (see IP_TOS option for UDP). Applies to sender only. 
+- IPv4 Type of Service (see IP_TOS option for IP) or IPv6 Traffic Class (see IPV6_TCLASS
+of IPv6) depending on socket address family. Applies to sender only. 
 - *Sender: user configurable, default: 0xB8*
 ---
 
@@ -465,7 +466,8 @@ regular development.*
 | --------------------- | ----- | ------- | --------- | ------ | ------------------ | ------ |
 | `SRTO_IPTTL`          | 1.0.5 | pre     | `int32_t` | hops   | (platform default) | 1..255 |
 
-- IP Time To Live (see IP_TTL option for UDP). Applies to sender only. 
+- IPv4 Time To Live (see IP_TTL option for IP) or IPv6 unicast hops (see IPV6_UNICAST_HOPS for
+IPV6) depending on socket address family. Applies to sender only. 
 - *Sender: user configurable, default: 64*
 ---
 
diff --git a/srtcore/channel.cpp b/srtcore/channel.cpp
index e4af2c6c3..6edbd6d2f 100644
--- a/srtcore/channel.cpp
+++ b/srtcore/channel.cpp
@@ -100,8 +100,8 @@ m_iIPversion(AF_INET),
 m_iSockAddrSize(sizeof(sockaddr_in)),
 m_iSocket(),
 #ifdef SRT_ENABLE_IPOPTS
-m_iIpTTL(-1),
-m_iIpToS(-1),
+m_iIpTTL(-1),   /* IPv4 TTL or IPv6 HOPs [1..255] (-1:undefined) */
+m_iIpToS(-1),   /* IPv4 Type of Service or IPv6 Traffic Class [0x00..0xff] (-1:undefined) */
 #endif
 m_iSndBufSize(65536),
 m_iRcvBufSize(65536)
@@ -198,13 +198,32 @@ void CChannel::setUDPSockOpt()
    #endif
 
 #ifdef SRT_ENABLE_IPOPTS
-      if ((-1 != m_iIpTTL)
-      &&  (0 != ::setsockopt(m_iSocket, IPPROTO_IP, IP_TTL, (const char*)&m_iIpTTL, sizeof(m_iIpTTL))))
-         throw CUDTException(MJ_SETUP, MN_NORES, NET_ERROR);
-         
-      if ((-1 != m_iIpToS)
-      &&  (0 != ::setsockopt(m_iSocket, IPPROTO_IP, IP_TOS, (const char*)&m_iIpToS, sizeof(m_iIpToS))))
-         throw CUDTException(MJ_SETUP, MN_NORES, NET_ERROR);
+      if (-1 != m_iIpTTL)
+      {
+         if(m_iIPversion == AF_INET)
+         {
+            if(0 != ::setsockopt(m_iSocket, IPPROTO_IP, IP_TTL, (const char*)&m_iIpTTL, sizeof(m_iIpTTL)))
+               throw CUDTException(MJ_SETUP, MN_NORES, NET_ERROR);
+         }
+         else //Assuming AF_INET6
+         {
+            if(0 != ::setsockopt(m_iSocket, IPPROTO_IPV6, IPV6_UNICAST_HOPS, (const char*)&m_iIpTTL, sizeof(m_iIpTTL)))
+               throw CUDTException(MJ_SETUP, MN_NORES, NET_ERROR);
+         }
+      }   
+      if (-1 != m_iIpToS)
+      {
+         if(m_iIPversion == AF_INET)
+         {
+            if(0 != ::setsockopt(m_iSocket, IPPROTO_IP, IP_TOS, (const char*)&m_iIpToS, sizeof(m_iIpToS)))
+               throw CUDTException(MJ_SETUP, MN_NORES, NET_ERROR);
+         }
+         else //Assuming AF_INET6
+         {
+            if(0 != ::setsockopt(m_iSocket, IPPROTO_IPV6, IPV6_TCLASS, (const char*)&m_iIpToS, sizeof(m_iIpToS)))
+               throw CUDTException(MJ_SETUP, MN_NORES, NET_ERROR);
+         }
+      }
 #endif
 
    timeval tv;
@@ -271,14 +290,28 @@ void CChannel::setRcvBufSize(int size)
 int CChannel::getIpTTL() const
 {
    socklen_t size = sizeof(m_iIpTTL);
-   ::getsockopt(m_iSocket, IPPROTO_IP, IP_TTL, (char *)&m_iIpTTL, &size);
+   if (m_iIPversion == AF_INET)
+   {
+      ::getsockopt(m_iSocket, IPPROTO_IP, IP_TTL, (char *)&m_iIpTTL, &size);
+   }
+   else
+   {
+      ::getsockopt(m_iSocket, IPPROTO_IPV6, IPV6_UNICAST_HOPS, (char *)&m_iIpTTL, &size);
+   }
    return m_iIpTTL;
 }
 
 int CChannel::getIpToS() const
 {
    socklen_t size = sizeof(m_iIpToS);
-   ::getsockopt(m_iSocket, IPPROTO_IP, IP_TOS, (char *)&m_iIpToS, &size);
+   if(m_iIPversion == AF_INET)
+   {
+      ::getsockopt(m_iSocket, IPPROTO_IP, IP_TOS, (char *)&m_iIpToS, &size);
+   }
+   else
+   {
+      ::getsockopt(m_iSocket, IPPROTO_IPV6, IPV6_TCLASS, (char *)&m_iIpToS, &size);
+   }
    return m_iIpToS;
 }