I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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#ifndef TUNNEL_CONFIG_H__
#define TUNNEL_CONFIG_H__
#include <inttypes.h>
#include <sstream>
#include <vector>
#include "aes.h"
#include "RouterInfo.h"
#include "RouterContext.h"
namespace i2p
{
namespace tunnel
{
struct TunnelHopConfig
{
const i2p::data::RouterInfo * router, * nextRouter;
uint32_t tunnelID, nextTunnelID;
uint8_t layerKey[32];
uint8_t ivKey[32];
uint8_t replyKey[32];
uint8_t replyIV[16];
bool isGateway, isEndpoint;
TunnelHopConfig * next, * prev;
i2p::crypto::TunnelDecryption decryption;
int recordIndex; // record # in tunnel build message
TunnelHopConfig (const i2p::data::RouterInfo * r)
{
CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
rnd.GenerateBlock (layerKey, 32);
rnd.GenerateBlock (ivKey, 32);
rnd.GenerateBlock (replyIV, 16);
tunnelID = rnd.GenerateWord32 ();
isGateway = true;
isEndpoint = true;
router = r;
nextRouter = 0;
nextTunnelID = 0;
next = 0;
prev = 0;
}
void SetNextRouter (const i2p::data::RouterInfo * r)
{
nextRouter = r;
isEndpoint = false;
CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
nextTunnelID = rnd.GenerateWord32 ();
}
void SetReplyHop (TunnelHopConfig * replyFirstHop)
{
nextRouter = replyFirstHop->router;
nextTunnelID = replyFirstHop->tunnelID;
isEndpoint = true;
}
void SetNext (TunnelHopConfig * n)
{
next = n;
if (next)
{
next->prev = this;
next->isGateway = false;
isEndpoint = false;
nextRouter = next->router;
nextTunnelID = next->tunnelID;
}
}
void SetPrev (TunnelHopConfig * p)
{
prev = p;
if (prev)
{
prev->next = this;
prev->isEndpoint = false;
isGateway = false;
}
}
};
class TunnelConfig
{
public:
TunnelConfig (std::vector<const i2p::data::RouterInfo *> peers,
TunnelConfig * replyTunnelConfig = 0) // replyTunnelConfig=0 means inbound
{
TunnelHopConfig * prev = nullptr;
for (auto it: peers)
{
auto hop = new TunnelHopConfig (it);
if (prev)
prev->SetNext (hop);
else
m_FirstHop = hop;
prev = hop;
}
m_LastHop = prev;
if (replyTunnelConfig) // outbound
{
m_FirstHop->isGateway = false;
m_LastHop->SetReplyHop (replyTunnelConfig->GetFirstHop ());
}
else // inbound
m_LastHop->SetNextRouter (&i2p::context.GetRouterInfo ());
}
~TunnelConfig ()
{
TunnelHopConfig * hop = m_FirstHop;
while (hop)
{
auto tmp = hop;
hop = hop->next;
delete tmp;
}
}
TunnelHopConfig * GetFirstHop () const
{
return m_FirstHop;
}
TunnelHopConfig * GetLastHop () const
{
return m_LastHop;
}
int GetNumHops () const
{
int num = 0;
TunnelHopConfig * hop = m_FirstHop;
while (hop)
{
num++;
hop = hop->next;
}
return num;
}
void Print (std::stringstream& s) const
{
TunnelHopConfig * hop = m_FirstHop;
if (!m_FirstHop->isGateway)
s << "me";
s << "-->" << m_FirstHop->tunnelID;
while (hop)
{
s << ":" << hop->router->GetIdentHashAbbreviation () << "-->";
if (!hop->isEndpoint)
s << hop->nextTunnelID;
else
return;
hop = hop->next;
}
// we didn't reach enpoint that mean we are last hop
s << ":me";
}
TunnelConfig * Invert () const
{
TunnelConfig * newConfig = new TunnelConfig ();
TunnelHopConfig * hop = m_FirstHop, * nextNewHop = nullptr;
while (hop)
{
TunnelHopConfig * newHop = new TunnelHopConfig (hop->router);
if (nextNewHop)
newHop->SetNext (nextNewHop);
nextNewHop = newHop;
newHop->isEndpoint = hop->isGateway;
newHop->isGateway = hop->isEndpoint;
if (!hop->prev) // first hop
{
newConfig->m_LastHop = newHop;
if (hop->isGateway) // inbound tunnel
newHop->SetReplyHop (m_FirstHop); // use it as reply tunnel
else
newHop->SetNextRouter (&i2p::context.GetRouterInfo ());
}
if (!hop->next) newConfig->m_FirstHop = newHop; // last hop
hop = hop->next;
}
return newConfig;
}
private:
// this constructor can't be called from outside
TunnelConfig (): m_FirstHop (nullptr), m_LastHop (nullptr)
{
}
private:
TunnelHopConfig * m_FirstHop, * m_LastHop;
};
}
}
#endif