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I2P: End-to-End encrypted and anonymous Internet
https://i2pd.website/
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424 lines
13 KiB
424 lines
13 KiB
#include <string.h> |
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#include <endian.h> |
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#include <cryptopp/sha.h> |
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#include <cryptopp/modes.h> |
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#include <cryptopp/aes.h> |
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#include <cryptopp/gzip.h> |
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#include "ElGamal.h" |
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#include "Timestamp.h" |
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#include "RouterContext.h" |
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#include "NetDb.h" |
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#include "Tunnel.h" |
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#include "base64.h" |
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#include "Transports.h" |
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#include "I2NPProtocol.h" |
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namespace i2p |
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{ |
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I2NPMessage * NewI2NPMessage () |
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{ |
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I2NPMessage * msg = new I2NPMessage; |
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msg->offset = 2; // reserve 2 bytes for NTCP header, should reserve more for SSU in future |
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msg->len = sizeof (I2NPHeader) + 2; |
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return msg; |
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} |
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void DeleteI2NPMessage (I2NPMessage * msg) |
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{ |
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delete msg; |
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} |
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void FillI2NPMessageHeader (I2NPMessage * msg, I2NPMessageType msgType, uint32_t replyMsgID) |
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{ |
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static uint32_t msgID = 0; |
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I2NPHeader * header = msg->GetHeader (); |
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header->typeID = msgType; |
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if (replyMsgID) // for tunnel creation |
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header->msgID = htobe32 (replyMsgID); |
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else |
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{ |
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header->msgID = htobe32 (msgID); |
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msgID++; |
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} |
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header->expiration = htobe64 (i2p::util::GetMillisecondsSinceEpoch () + 5000); // TODO: 5 secs is a magic number |
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int len = msg->GetLength () - sizeof (I2NPHeader); |
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header->size = htobe16 (len); |
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uint8_t hash[32]; |
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CryptoPP::SHA256().CalculateDigest(hash, msg->GetPayload (), len); |
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header->chks = hash[0]; |
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} |
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I2NPMessage * CreateI2NPMessage (I2NPMessageType msgType, const uint8_t * buf, int len, uint32_t replyMsgID) |
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{ |
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I2NPMessage * msg = NewI2NPMessage (); |
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memcpy (msg->GetPayload (), buf, len); |
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msg->len += len; |
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FillI2NPMessageHeader (msg, msgType, replyMsgID); |
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return msg; |
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} |
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I2NPMessage * CreateI2NPMessage (const uint8_t * buf, int len) |
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{ |
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I2NPMessage * msg = NewI2NPMessage (); |
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memcpy (msg->GetBuffer (), buf, len); |
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msg->len += msg->offset + len; |
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return msg; |
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} |
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I2NPMessage * CreateDeliveryStatusMsg () |
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{ |
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#pragma pack(1) |
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struct |
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{ |
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uint32_t msgID; |
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uint64_t timestamp; |
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} msg; |
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#pragma pack () |
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msg.msgID = 0; |
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msg.timestamp = htobe64 (i2p::util::GetMillisecondsSinceEpoch ()); |
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return CreateI2NPMessage (eI2NPDeliveryStatus, (uint8_t *)&msg, sizeof (msg)); |
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} |
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I2NPMessage * CreateDatabaseLookupMsg (const uint8_t * key, const uint8_t * from, |
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uint32_t replyTunnelID, bool exploratory) |
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{ |
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I2NPMessage * m = NewI2NPMessage (); |
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uint8_t * buf = m->GetPayload (); |
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memcpy (buf, key, 32); // key |
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buf += 32; |
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memcpy (buf, from, 32); // from |
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buf += 32; |
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if (replyTunnelID) |
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{ |
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*buf = 0x01; // set delivery flag |
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*(uint32_t *)(buf+1) = htobe32 (replyTunnelID); |
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buf += 5; |
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} |
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else |
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{ |
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*buf = 0; // flag |
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buf++; |
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} |
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if (exploratory) |
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{ |
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*(uint16_t *)buf = htobe16 (1); // one exlude record |
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buf += 2; |
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// reply with non-floodfill routers only |
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memset (buf, 0, 32); |
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buf += 32; |
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} |
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else |
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{ |
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// nothing to exclude |
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*(uint16_t *)buf = htobe16 (0); |
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buf += 2; |
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} |
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m->len += (buf - m->GetPayload ()); |
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FillI2NPMessageHeader (m, eI2NPDatabaseLookup); |
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return m; |
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} |
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I2NPMessage * CreateDatabaseStoreMsg () |
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{ |
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I2NPMessage * m = NewI2NPMessage (); |
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I2NPDatabaseStoreMsg * msg = (I2NPDatabaseStoreMsg *)m->GetPayload (); |
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memcpy (msg->key, context.GetRouterInfo ().GetIdentHash (), 32); |
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msg->type = 0; |
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msg->replyToken = 0; |
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CryptoPP::Gzip compressor; |
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compressor.Put ((uint8_t *)context.GetRouterInfo ().GetBuffer (), context.GetRouterInfo ().GetBufferLen ()); |
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compressor.MessageEnd(); |
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int size = compressor.MaxRetrievable (); |
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uint8_t * buf = m->GetPayload () + sizeof (I2NPDatabaseStoreMsg); |
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*(uint16_t *)buf = htobe16 (size); // size |
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buf += 2; |
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compressor.Get (buf, size); |
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m->len += sizeof (I2NPDatabaseStoreMsg) + 2 + size; // payload size |
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FillI2NPMessageHeader (m, eI2NPDatabaseStore); |
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return m; |
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} |
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I2NPBuildRequestRecordClearText CreateBuildRequestRecord ( |
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const uint8_t * ourIdent, uint32_t receiveTunnelID, |
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const uint8_t * nextIdent, uint32_t nextTunnelID, |
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const uint8_t * layerKey,const uint8_t * ivKey, |
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const uint8_t * replyKey, const uint8_t * replyIV, uint32_t nextMessageID, |
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bool isGateway, bool isEndpoint) |
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{ |
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I2NPBuildRequestRecordClearText clearText; |
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clearText.receiveTunnel = htobe32 (receiveTunnelID); |
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clearText.nextTunnel = htobe32(nextTunnelID); |
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memcpy (clearText.layerKey, layerKey, 32); |
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memcpy (clearText.ivKey, ivKey, 32); |
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memcpy (clearText.replyKey, replyKey, 32); |
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memcpy (clearText.replyIV, replyIV, 16); |
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clearText.flag = 0; |
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if (isGateway) clearText.flag |= 0x80; |
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if (isEndpoint) clearText.flag |= 0x40; |
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memcpy (clearText.ourIdent, ourIdent, 32); |
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memcpy (clearText.nextIdent, nextIdent, 32); |
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clearText.requestTime = i2p::util::GetHoursSinceEpoch (); |
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clearText.nextMessageID = htobe32(nextMessageID); |
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return clearText; |
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} |
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void EncryptBuildRequestRecord (const i2p::data::RouterInfo& router, |
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const I2NPBuildRequestRecordClearText& clearText, |
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I2NPBuildRequestRecordElGamalEncrypted& record) |
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{ |
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i2p::crypto::ElGamalEncrypt (router.GetRouterIdentity ().publicKey, (uint8_t *)&clearText, sizeof(clearText), record.encrypted); |
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memcpy (record.toPeer, (const uint8_t *)router.GetIdentHash (), 16); |
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} |
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void HandleVariableTunnelBuildMsg (uint32_t replyMsgID, uint8_t * buf, size_t len) |
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{ |
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int num = buf[0]; |
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LogPrint ("VariableTunnelBuild ", num, " records"); |
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i2p::tunnel::Tunnel * tunnel = i2p::tunnel::tunnels.GetPendingTunnel (replyMsgID); |
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if (tunnel) |
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{ |
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// endpoint of inbound tunnel |
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LogPrint ("VariableTunnelBuild reply for tunnel ", tunnel->GetTunnelID ()); |
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if (tunnel->HandleTunnelBuildResponse (buf, len)) |
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{ |
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LogPrint ("Inbound tunnel ", tunnel->GetTunnelID (), " has been created"); |
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i2p::tunnel::tunnels.AddInboundTunnel (static_cast<i2p::tunnel::InboundTunnel *>(tunnel)); |
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} |
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else |
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{ |
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LogPrint ("Inbound tunnel ", tunnel->GetTunnelID (), " has been declined"); |
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delete tunnel; |
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} |
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} |
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else |
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{ |
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I2NPBuildRequestRecordElGamalEncrypted * records = (I2NPBuildRequestRecordElGamalEncrypted *)(buf+1); |
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for (int i = 0; i < num; i++) |
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{ |
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if (!memcmp (records[i].toPeer, (const uint8_t *)i2p::context.GetRouterInfo ().GetIdentHash (), 16)) |
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{ |
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LogPrint ("Record ",i," is ours"); |
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I2NPBuildRequestRecordClearText clearText; |
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i2p::crypto::ElGamalDecrypt (i2p::context.GetPrivateKey (), records[i].encrypted, (uint8_t *)&clearText); |
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i2p::tunnel::TransitTunnel * transitTunnel = |
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i2p::tunnel::CreateTransitTunnel ( |
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be32toh (clearText.receiveTunnel), |
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clearText.nextIdent, be32toh (clearText.nextTunnel), |
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clearText.layerKey, clearText.ivKey, |
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clearText.flag & 0x80, clearText.flag & 0x40); |
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i2p::tunnel::tunnels.AddTransitTunnel (transitTunnel); |
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// replace record to reply |
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I2NPBuildResponseRecord * reply = (I2NPBuildResponseRecord *)(records + i); |
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reply->ret = 0; |
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//TODO: fill filler |
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CryptoPP::SHA256().CalculateDigest(reply->hash, reply->padding, sizeof (reply->padding) + 1); // + 1 byte of ret |
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// encrypt reply |
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CryptoPP::CBC_Mode<CryptoPP::AES>::Encryption encryption; |
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for (int j = 0; j < num; j++) |
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{ |
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encryption.SetKeyWithIV (clearText.replyKey, 32, clearText.replyIV); |
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encryption.ProcessData((uint8_t *)(records + j), (uint8_t *)(records + j), sizeof (records[j])); |
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} |
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if (clearText.flag & 0x40) // we are endpoint of outboud tunnel |
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{ |
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// so we send it to reply tunnel |
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i2p::transports.SendMessage (clearText.nextIdent, |
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CreateTunnelGatewayMsg (be32toh (clearText.nextTunnel), |
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eI2NPVariableTunnelBuildReply, buf, len, |
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be32toh (clearText.nextMessageID))); |
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} |
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else |
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i2p::transports.SendMessage (clearText.nextIdent, |
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CreateI2NPMessage (eI2NPVariableTunnelBuild, buf, len, be32toh (clearText.nextMessageID))); |
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return; |
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} |
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} |
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} |
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} |
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void HandleVariableTunnelBuildReplyMsg (uint32_t replyMsgID, uint8_t * buf, size_t len) |
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{ |
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LogPrint ("VariableTunnelBuildReplyMsg replyMsgID=", replyMsgID); |
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i2p::tunnel::Tunnel * tunnel = i2p::tunnel::tunnels.GetPendingTunnel (replyMsgID); |
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if (tunnel) |
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{ |
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// reply for outbound tunnel |
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if (tunnel->HandleTunnelBuildResponse (buf, len)) |
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{ |
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LogPrint ("Outbound tunnel ", tunnel->GetTunnelID (), " has been created"); |
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i2p::tunnel::tunnels.AddOutboundTunnel (static_cast<i2p::tunnel::OutboundTunnel *>(tunnel)); |
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} |
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else |
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{ |
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LogPrint ("Outbound tunnel ", tunnel->GetTunnelID (), " has been declined"); |
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delete tunnel; |
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} |
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} |
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else |
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LogPrint ("Pending tunnel for message ", replyMsgID, " not found"); |
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} |
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I2NPMessage * CreateTunnelDataMsg (const uint8_t * buf) |
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{ |
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I2NPMessage * msg = NewI2NPMessage (); |
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memcpy (msg->GetPayload (), buf, i2p::tunnel::TUNNEL_DATA_MSG_SIZE); |
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msg->len += i2p::tunnel::TUNNEL_DATA_MSG_SIZE; |
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FillI2NPMessageHeader (msg, eI2NPTunnelData); |
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return msg; |
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} |
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I2NPMessage * CreateTunnelDataMsg (uint32_t tunnelID, const uint8_t * payload) |
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{ |
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I2NPMessage * msg = NewI2NPMessage (); |
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memcpy (msg->GetPayload () + 4, payload, i2p::tunnel::TUNNEL_DATA_MSG_SIZE - 4); |
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*(uint32_t *)(msg->GetPayload ()) = htobe32 (tunnelID); |
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msg->len += i2p::tunnel::TUNNEL_DATA_MSG_SIZE; |
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FillI2NPMessageHeader (msg, eI2NPTunnelData); |
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return msg; |
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} |
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I2NPMessage * CreateTunnelGatewayMsg (uint32_t tunnelID, const uint8_t * buf, size_t len) |
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{ |
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I2NPMessage * msg = NewI2NPMessage (); |
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TunnelGatewayHeader * header = (TunnelGatewayHeader *)msg->GetPayload (); |
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header->tunnelID = htobe32 (tunnelID); |
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header->length = htobe16 (len); |
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memcpy (msg->GetPayload () + sizeof (TunnelGatewayHeader), buf, len); |
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msg->len += sizeof (TunnelGatewayHeader) + len; |
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FillI2NPMessageHeader (msg, eI2NPTunnelGateway); |
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return msg; |
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} |
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I2NPMessage * CreateTunnelGatewayMsg (uint32_t tunnelID, I2NPMessage * msg) |
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{ |
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if (msg->offset >= sizeof (I2NPHeader) + sizeof (TunnelGatewayHeader)) |
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{ |
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// message is capable to be used without copying |
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TunnelGatewayHeader * header = (TunnelGatewayHeader *)(msg->GetBuffer () - sizeof (TunnelGatewayHeader)); |
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header->tunnelID = htobe32 (tunnelID); |
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int len = msg->GetLength (); |
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header->length = htobe16 (len); |
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msg->offset -= (sizeof (I2NPHeader) + sizeof (TunnelGatewayHeader)); |
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msg->len = msg->offset + sizeof (I2NPHeader) + sizeof (TunnelGatewayHeader) +len; |
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FillI2NPMessageHeader (msg, eI2NPTunnelGateway); |
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return msg; |
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} |
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else |
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{ |
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I2NPMessage * msg1 = CreateTunnelGatewayMsg (tunnelID, msg->GetBuffer (), msg->GetLength ()); |
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DeleteI2NPMessage (msg); |
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return msg1; |
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} |
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} |
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I2NPMessage * CreateTunnelGatewayMsg (uint32_t tunnelID, I2NPMessageType msgType, |
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const uint8_t * buf, size_t len, uint32_t replyMsgID) |
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{ |
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I2NPMessage * msg = NewI2NPMessage (); |
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size_t gatewayMsgOffset = sizeof (I2NPHeader) + sizeof (TunnelGatewayHeader); |
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msg->offset += gatewayMsgOffset; |
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msg->len += gatewayMsgOffset; |
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memcpy (msg->GetPayload (), buf, len); |
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msg->len += len; |
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FillI2NPMessageHeader (msg, msgType, replyMsgID); // create content message |
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len = msg->GetLength (); |
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msg->offset -= gatewayMsgOffset; |
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TunnelGatewayHeader * header = (TunnelGatewayHeader *)msg->GetPayload (); |
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header->tunnelID = htobe32 (tunnelID); |
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header->length = htobe16 (len); |
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FillI2NPMessageHeader (msg, eI2NPTunnelGateway); // gateway message |
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return msg; |
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} |
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void HandleTunnelGatewayMsg (I2NPMessage * msg) |
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{ |
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TunnelGatewayHeader * header = (TunnelGatewayHeader *)msg->GetPayload (); |
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uint32_t tunnelID = be32toh(header->tunnelID); |
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uint16_t len = be16toh(header->length); |
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LogPrint ("TunnelGateway of ", (int)len, " bytes for tunnel ", (unsigned int)tunnelID); |
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i2p::tunnel::TransitTunnel * tunnel = i2p::tunnel::tunnels.GetTransitTunnel (tunnelID); |
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if (tunnel) |
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{ |
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// we make payload as new I2NP message to send |
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msg->offset += sizeof (I2NPHeader) + sizeof (TunnelGatewayHeader); |
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msg->len = msg->offset + len; |
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tunnel->SendTunnelDataMsg (nullptr, 0, msg); |
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} |
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else |
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{ |
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LogPrint ("Tunnel ", (unsigned int)tunnelID, " not found"); |
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i2p::DeleteI2NPMessage (msg); |
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} |
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} |
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void HandleI2NPMessage (uint8_t * msg, size_t len) |
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{ |
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I2NPHeader * header = (I2NPHeader *)msg; |
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uint32_t msgID = be32toh (header->msgID); |
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LogPrint ("I2NP msg received len=", len,", type=", (int)header->typeID, ", msgID=", (unsigned int)msgID); |
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uint8_t * buf = msg + sizeof (I2NPHeader); |
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int size = be16toh (header->size); |
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switch (header->typeID) |
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{ |
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case eI2NPGarlic: |
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LogPrint ("Garlic"); |
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break; |
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break; |
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case eI2NPDeliveryStatus: |
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LogPrint ("DeliveryStatus"); |
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break; |
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case eI2NPVariableTunnelBuild: |
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LogPrint ("VariableTunnelBuild"); |
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HandleVariableTunnelBuildMsg (msgID, buf, size); |
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break; |
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case eI2NPVariableTunnelBuildReply: |
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LogPrint ("VariableTunnelBuildReply"); |
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HandleVariableTunnelBuildReplyMsg (msgID, buf, size); |
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break; |
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default: |
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LogPrint ("Unexpected message ", (int)header->typeID); |
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} |
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} |
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void HandleI2NPMessage (I2NPMessage * msg) |
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{ |
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if (msg) |
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{ |
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switch (msg->GetHeader ()->typeID) |
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{ |
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case eI2NPTunnelData: |
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LogPrint ("TunnelData"); |
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i2p::tunnel::tunnels.PostTunnelData (msg); |
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break; |
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case eI2NPTunnelGateway: |
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LogPrint ("TunnelGateway"); |
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HandleTunnelGatewayMsg (msg); |
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break; |
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case eI2NPDatabaseStore: |
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LogPrint ("DatabaseStore"); |
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i2p::data::netdb.PostI2NPMsg (msg); |
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break; |
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case eI2NPDatabaseSearchReply: |
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LogPrint ("DatabaseSearchReply"); |
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i2p::data::netdb.PostI2NPMsg (msg); |
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break; |
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default: |
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HandleI2NPMessage (msg->GetBuffer (), msg->GetLength ()); |
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DeleteI2NPMessage (msg); |
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} |
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} |
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} |
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}
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