ddnet/src/engine/shared/network_stun.cpp

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#include "network.h"
#include <base/log.h>
#include <base/system.h>
static int IndexFromNetType(int NetType)
{
switch(NetType)
{
case NETTYPE_IPV6:
return 0;
case NETTYPE_IPV4:
return 1;
}
return -1;
}
static const char *IndexToSystem(int Index)
{
switch(Index)
{
case 0:
return "stun/6";
case 1:
return "stun/4";
}
dbg_break();
return nullptr;
}
static int RetryWaitSeconds(int NumUnsuccessfulTries)
{
return (1 << clamp(NumUnsuccessfulTries, 0, 9));
}
CStun::CProtocol::CProtocol(int Index, NETSOCKET Socket) :
m_Index(Index),
m_Socket(Socket)
{
mem_zero(&m_StunServer, sizeof(NETADDR));
// Initialize `m_Stun` with random data.
unsigned char aBuf[32];
StunMessagePrepare(aBuf, sizeof(aBuf), &m_Stun);
}
void CStun::CProtocol::FeedStunServer(NETADDR StunServer)
{
if(m_HaveStunServer && net_addr_comp(&m_StunServer, &StunServer) == 0)
{
return;
}
m_HaveStunServer = true;
m_StunServer = StunServer;
m_NumUnsuccessfulTries = 0;
Refresh();
}
void CStun::CProtocol::Refresh()
{
m_NextTry = time_get();
}
void CStun::CProtocol::Update()
{
int64_t Now = time_get();
if(m_NextTry == -1 || Now < m_NextTry || !m_HaveStunServer)
{
return;
}
m_NextTry = Now + RetryWaitSeconds(m_NumUnsuccessfulTries) * time_freq();
m_NumUnsuccessfulTries += 1;
unsigned char aBuf[32];
int Size = StunMessagePrepare(aBuf, sizeof(aBuf), &m_Stun);
if(net_udp_send(m_Socket, &m_StunServer, aBuf, Size) == -1)
{
log_debug(IndexToSystem(m_Index), "couldn't send stun request");
return;
}
}
bool CStun::CProtocol::OnPacket(NETADDR Addr, unsigned char *pData, int DataSize)
{
if(m_NextTry < 0 || !m_HaveStunServer)
{
return false;
}
bool Success;
NETADDR StunAddr;
if(StunMessageParse(pData, DataSize, &m_Stun, &Success, &StunAddr))
{
return false;
}
m_LastResponse = time_get();
if(!Success)
{
m_HaveAddr = false;
log_debug(IndexToSystem(m_Index), "got error response");
return true;
}
m_NextTry = -1;
m_NumUnsuccessfulTries = -1;
m_HaveAddr = true;
m_Addr = StunAddr;
char aStunAddr[NETADDR_MAXSTRSIZE];
net_addr_str(&StunAddr, aStunAddr, sizeof(aStunAddr), true);
log_debug(IndexToSystem(m_Index), "got address: %s", aStunAddr);
return true;
}
CONNECTIVITY CStun::CProtocol::GetConnectivity(NETADDR *pGlobalAddr)
{
if(!m_HaveStunServer)
{
return CONNECTIVITY::UNKNOWN;
}
int64_t Now = time_get();
int64_t Freq = time_freq();
bool HaveTriedALittle = m_NumUnsuccessfulTries >= 5 && (m_LastResponse == -1 || Now - m_LastResponse >= 30 * Freq);
if(m_LastResponse == -1 && !HaveTriedALittle)
{
return CONNECTIVITY::CHECKING;
}
else if(HaveTriedALittle)
{
return CONNECTIVITY::UNREACHABLE;
}
else if(!m_HaveAddr)
{
return CONNECTIVITY::REACHABLE;
}
else
{
*pGlobalAddr = m_Addr;
return CONNECTIVITY::ADDRESS_KNOWN;
}
}
CStun::CStun(NETSOCKET Socket) :
m_aProtocols{CProtocol(0, Socket), CProtocol(1, Socket)}
{
}
void CStun::FeedStunServer(NETADDR StunServer)
{
int Index = IndexFromNetType(StunServer.type);
if(Index < 0)
{
return;
}
m_aProtocols[Index].FeedStunServer(StunServer);
}
void CStun::Refresh()
{
for(auto &Protocol : m_aProtocols)
{
Protocol.Refresh();
}
}
void CStun::Update()
{
for(auto &Protocol : m_aProtocols)
{
Protocol.Update();
}
}
bool CStun::OnPacket(NETADDR Addr, unsigned char *pData, int DataSize)
{
int Index = IndexFromNetType(Addr.type);
if(Index < 0)
{
return false;
}
return m_aProtocols[Index].OnPacket(Addr, pData, DataSize);
}
CONNECTIVITY CStun::GetConnectivity(int NetType, NETADDR *pGlobalAddr)
{
int Index = IndexFromNetType(NetType);
dbg_assert(Index != -1, "invalid nettype");
return m_aProtocols[Index].GetConnectivity(pGlobalAddr);
}