Add SRTO_IPV6ONLY option

srtcore/api.cpp

@@ -1690,6 +1690,7 @@ void CUDTUnited::updateMux(
 #endif
    m.m_pChannel->setSndBufSize(s->m_pUDT->m_iUDPSndBufSize);
    m.m_pChannel->setRcvBufSize(s->m_pUDT->m_iUDPRcvBufSize);
+   m.m_pChannel->setIpV6Only(s->m_pUDT->m_bIpV6Only);
 
    try
    {

srtcore/channel.cpp

@@ -102,7 +102,8 @@ 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)
+m_iRcvBufSize(65536),
+m_iIpV6Only(-1)
 {
 }
 
@@ -115,6 +116,7 @@ m_iIpToS(-1),
 #endif
 m_iSndBufSize(65536),
 m_iRcvBufSize(65536),
+m_iIpV6Only(-1),
 m_BindAddr(version)
 {
    m_iSockAddrSize = (AF_INET == m_iIPversion) ? sizeof(sockaddr_in) : sizeof(sockaddr_in6);
@@ -136,6 +138,9 @@ void CChannel::open(const sockaddr* addr)
    #endif
       throw CUDTException(MJ_SETUP, MN_NONE, NET_ERROR);
 
+   if ((m_iIpV6Only != -1) && (m_iIPversion == AF_INET6)) // (not an error if it fails)
+      ::setsockopt(m_iSocket, IPPROTO_IPV6, IPV6_V6ONLY, (const char*)(&m_iIpV6Only), sizeof(m_iIpV6Only));
+
    if (NULL != addr)
    {
       socklen_t namelen = m_iSockAddrSize;
@@ -287,6 +292,11 @@ void CChannel::setRcvBufSize(int size)
    m_iRcvBufSize = size;
 }
 
+void CChannel::setIpV6Only(bool ipV6Only) 
+{
+   m_iIpV6Only = ipV6Only;
+}
+
 #ifdef SRT_ENABLE_IPOPTS
 int CChannel::getIpTTL() const
 {

srtcore/channel.h

@@ -106,6 +106,11 @@ class CChannel
 
    void setRcvBufSize(int size);
 
+   /// Set the IPV6ONLY option.
+   /// @param [in] IPV6ONLY value.
+
+   void setIpV6Only(bool ipV6Only);
+
       /// Query the socket address that the channel is using.
       /// @param [out] addr pointer to store the returned socket address.
 
@@ -174,6 +179,7 @@ class CChannel
 #endif
    int m_iSndBufSize;                   // UDP sending buffer size
    int m_iRcvBufSize;                   // UDP receiving buffer size
+   int m_iIpV6Only;                     // IPV6_V6ONLY option (-1 if not set)
    sockaddr_any m_BindAddr;
 };
 

srtcore/core.cpp

@@ -264,6 +264,7 @@ CUDT::CUDT()
    m_bTLPktDrop = true;         //Too-late Packet Drop
    m_bMessageAPI = true;
    m_zOPT_ExpPayloadSize = SRT_LIVE_DEF_PLSIZE;
+   m_bIpV6Only = true;
    //Runtime
    m_bRcvNakReport = true;      //Receiver's Periodic NAK Reports
    m_llInputBW = 0;             // Application provided input bandwidth (internal input rate sampling == 0)
@@ -326,6 +327,7 @@ CUDT::CUDT(const CUDT& ancestor)
    m_zOPT_ExpPayloadSize = ancestor.m_zOPT_ExpPayloadSize;
    m_bTLPktDrop = ancestor.m_bTLPktDrop;
    m_bMessageAPI = ancestor.m_bMessageAPI;
+   m_bIpV6Only = ancestor.m_bIpV6Only;
    //Runtime
    m_bRcvNakReport = ancestor.m_bRcvNakReport;
 
@@ -844,6 +846,13 @@ void CUDT::setOpt(SRT_SOCKOPT optName, const void* optval, int optlen)
         m_bOPT_StrictEncryption = bool_int_value(optval, optlen);
         break;
 
+   case SRTO_IPV6ONLY:
+      if (m_bConnected)
+         throw CUDTException(MJ_NOTSUP, MN_ISCONNECTED, 0);
+
+      m_bIpV6Only = bool_int_value(optval, optlen);
+      break;
+
     default:
         throw CUDTException(MJ_NOTSUP, MN_INVAL, 0);
     }
@@ -1116,6 +1125,11 @@ void CUDT::getOpt(SRT_SOCKOPT optName, void* optval, int& optlen)
       *(int32_t*)optval = m_bOPT_StrictEncryption;
       break;
 
+   case SRTO_IPV6ONLY:
+      optlen = sizeof(int32_t);
+      *(int32_t*)optval = m_bIpV6Only;
+      break;
+
    default:
       throw CUDTException(MJ_NOTSUP, MN_NONE, 0);
    }

srtcore/core.h

@@ -573,6 +573,7 @@ class CUDT
     int64_t m_llInputBW;                         // Input stream rate (bytes/sec)
     int m_iOverheadBW;                           // Percent above input stream rate (applies if m_llMaxBW == 0)
     bool m_bRcvNakReport;                        // Enable Receiver Periodic NAK Reports
+    bool m_bIpV6Only;                            // IPV6_V6ONLY option
 private:
     UniquePtr<CCryptoControl> m_pCryptoControl;                            // congestion control SRT class (small data extension)
     CCache<CInfoBlock>* m_pCache;                // network information cache

srtcore/srt.h

@@ -180,6 +180,7 @@ typedef enum SRT_SOCKOPT {
    SRTO_KMREFRESHRATE,       // After sending how many packets the encryption key should be flipped to the new key
    SRTO_KMPREANNOUNCE,       // How many packets before key flip the new key is annnounced and after key flip the old one decommissioned
    SRTO_STRICTENC,           // Connection to be rejected or quickly broken when one side encryption set or bad password
+   SRTO_IPV6ONLY,            // IPV6_V6ONLY mode
 } SRT_SOCKOPT;
 
 // DEPRECATED OPTIONS:
@@ -501,7 +502,7 @@ inline bool operator&(int flags, SRT_EPOLL_OPT eflg)
     // Using an enum prevents treating int automatically as enum,
     // requires explicit enum to be passed here, and minimizes the
     // risk that the right side value will contain multiple flags.
-    return flags & int(eflg);
+    return (flags & int(eflg)) != 0;
 }
 #endif