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i2pd/libi2pd/I2NPProtocol.cpp
Anatolii Cherednichenko 55534ea002 Reformat code
2022-08-30 02:11:28 +03:00

776 lines
36 KiB
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/*
* Copyright (c) 2013-2022, The PurpleI2P Project
*
* This file is part of Purple i2pd project and licensed under BSD3
*
* See full license text in LICENSE file at top of project tree
*/
#include <string.h>
#include <atomic>
#include "Base.h"
#include "Log.h"
#include "Crypto.h"
#include "I2PEndian.h"
#include "Timestamp.h"
#include "RouterContext.h"
#include "NetDb.hpp"
#include "Tunnel.h"
#include "Transports.h"
#include "Garlic.h"
#include "ECIESX25519AEADRatchetSession.h"
#include "I2NPProtocol.h"
#include "version.h"
using namespace i2p::transport;
namespace i2p {
std::shared_ptr<I2NPMessage> NewI2NPMessage() {
return std::make_shared<I2NPMessageBuffer<I2NP_MAX_MESSAGE_SIZE> >();
}
std::shared_ptr<I2NPMessage> NewI2NPShortMessage() {
return std::make_shared<I2NPMessageBuffer<I2NP_MAX_SHORT_MESSAGE_SIZE> >();
}
std::shared_ptr<I2NPMessage> NewI2NPTunnelMessage(bool endpoint) {
return i2p::tunnel::tunnels.NewI2NPTunnelMessage(endpoint);
}
std::shared_ptr<I2NPMessage> NewI2NPMessage(size_t len) {
return (len < I2NP_MAX_SHORT_MESSAGE_SIZE - I2NP_HEADER_SIZE - 2) ? NewI2NPShortMessage() : NewI2NPMessage();
}
void I2NPMessage::FillI2NPMessageHeader(I2NPMessageType msgType, uint32_t replyMsgID, bool checksum) {
SetTypeID(msgType);
if (!replyMsgID) RAND_bytes((uint8_t * ) & replyMsgID, 4);
SetMsgID(replyMsgID);
SetExpiration(i2p::util::GetMillisecondsSinceEpoch() + I2NP_MESSAGE_EXPIRATION_TIMEOUT);
UpdateSize();
if (checksum) UpdateChks();
}
void I2NPMessage::RenewI2NPMessageHeader() {
uint32_t msgID;
RAND_bytes((uint8_t * ) & msgID, 4);
SetMsgID(msgID);
SetExpiration(i2p::util::GetMillisecondsSinceEpoch() + I2NP_MESSAGE_EXPIRATION_TIMEOUT);
}
bool I2NPMessage::IsExpired() const {
auto ts = i2p::util::GetMillisecondsSinceEpoch();
auto exp = GetExpiration();
return (ts > exp + I2NP_MESSAGE_CLOCK_SKEW) ||
(ts < exp - 3 * I2NP_MESSAGE_CLOCK_SKEW); // check if expired or too far in future
}
std::shared_ptr<I2NPMessage>
CreateI2NPMessage(I2NPMessageType msgType, const uint8_t *buf, size_t len, uint32_t replyMsgID) {
auto msg = NewI2NPMessage(len);
if (msg->Concat(buf, len) < len)
LogPrint(eLogError, "I2NP: Message length ", len, " exceeds max length ", msg->maxLen);
msg->FillI2NPMessageHeader(msgType, replyMsgID);
return msg;
}
std::shared_ptr<I2NPMessage>
CreateI2NPMessage(const uint8_t *buf, size_t len, std::shared_ptr<i2p::tunnel::InboundTunnel> from) {
auto msg = NewI2NPMessage();
if (msg->offset + len < msg->maxLen) {
memcpy(msg->GetBuffer(), buf, len);
msg->len = msg->offset + len;
msg->from = from;
} else
LogPrint(eLogError, "I2NP: Message length ", len, " exceeds max length");
return msg;
}
std::shared_ptr<I2NPMessage> CopyI2NPMessage(std::shared_ptr<I2NPMessage> msg) {
if (!msg) return nullptr;
auto newMsg = NewI2NPMessage(msg->len);
newMsg->offset = msg->offset;
*newMsg = *msg;
return newMsg;
}
std::shared_ptr<I2NPMessage> CreateDeliveryStatusMsg(uint32_t msgID) {
auto m = NewI2NPShortMessage();
uint8_t *buf = m->GetPayload();
if (msgID) {
htobe32buf(buf + DELIVERY_STATUS_MSGID_OFFSET, msgID);
htobe64buf(buf + DELIVERY_STATUS_TIMESTAMP_OFFSET, i2p::util::GetMillisecondsSinceEpoch());
} else // for SSU establishment
{
RAND_bytes((uint8_t * ) & msgID, 4);
htobe32buf(buf + DELIVERY_STATUS_MSGID_OFFSET, msgID);
htobe64buf(buf + DELIVERY_STATUS_TIMESTAMP_OFFSET, i2p::context.GetNetID());
}
m->len += DELIVERY_STATUS_SIZE;
m->FillI2NPMessageHeader(eI2NPDeliveryStatus);
return m;
}
std::shared_ptr<I2NPMessage> CreateRouterInfoDatabaseLookupMsg(const uint8_t *key, const uint8_t *from,
uint32_t replyTunnelID, bool exploratory,
std::set<i2p::data::IdentHash> *excludedPeers) {
auto m = excludedPeers ? NewI2NPMessage() : NewI2NPShortMessage();
uint8_t *buf = m->GetPayload();
memcpy(buf, key, 32); // key
buf += 32;
memcpy(buf, from, 32); // from
buf += 32;
uint8_t flag = exploratory ? DATABASE_LOOKUP_TYPE_EXPLORATORY_LOOKUP : DATABASE_LOOKUP_TYPE_ROUTERINFO_LOOKUP;
if (replyTunnelID) {
*buf = flag | DATABASE_LOOKUP_DELIVERY_FLAG; // set delivery flag
htobe32buf(buf + 1, replyTunnelID);
buf += 5;
} else {
*buf = flag; // flag
buf++;
}
if (excludedPeers) {
int cnt = excludedPeers->size();
htobe16buf(buf, cnt);
buf += 2;
for (auto &it: *excludedPeers) {
memcpy(buf, it, 32);
buf += 32;
}
} else {
// nothing to exclude
htobuf16(buf, 0);
buf += 2;
}
m->len += (buf - m->GetPayload());
m->FillI2NPMessageHeader(eI2NPDatabaseLookup);
return m;
}
std::shared_ptr<I2NPMessage> CreateLeaseSetDatabaseLookupMsg(const i2p::data::IdentHash &dest,
const std::set<i2p::data::IdentHash> &excludedFloodfills,
std::shared_ptr<const i2p::tunnel::InboundTunnel> replyTunnel,
const uint8_t *replyKey,
const uint8_t *replyTag, bool replyECIES) {
int cnt = excludedFloodfills.size();
auto m = cnt > 7 ? NewI2NPMessage() : NewI2NPShortMessage();
uint8_t *buf = m->GetPayload();
memcpy(buf, dest, 32); // key
buf += 32;
memcpy(buf, replyTunnel->GetNextIdentHash(), 32); // reply tunnel GW
buf += 32;
*buf = DATABASE_LOOKUP_DELIVERY_FLAG | DATABASE_LOOKUP_TYPE_LEASESET_LOOKUP; // flags
*buf |= (replyECIES ? DATABASE_LOOKUP_ECIES_FLAG : DATABASE_LOOKUP_ENCRYPTION_FLAG);
buf++;
htobe32buf(buf, replyTunnel->GetNextTunnelID()); // reply tunnel ID
buf += 4;
// excluded
if (cnt > 512) {
LogPrint(eLogWarning, "I2NP: Too many peers to exclude ", cnt, " for DatabaseLookup");
cnt = 0;
}
htobe16buf(buf, cnt);
buf += 2;
if (cnt > 0) {
for (auto &it: excludedFloodfills) {
memcpy(buf, it, 32);
buf += 32;
}
}
// encryption
memcpy(buf, replyKey, 32);
buf[32] = 1; // 1 tag
if (replyECIES) {
memcpy(buf + 33, replyTag, 8); // 8 bytes tag
buf += 41;
} else {
memcpy(buf + 33, replyTag, 32); // 32 bytes tag
buf += 65;
}
m->len += (buf - m->GetPayload());
m->FillI2NPMessageHeader(eI2NPDatabaseLookup);
return m;
}
std::shared_ptr<I2NPMessage> CreateDatabaseSearchReply(const i2p::data::IdentHash &ident,
std::vector<i2p::data::IdentHash> routers) {
auto m = NewI2NPShortMessage();
uint8_t *buf = m->GetPayload();
size_t len = 0;
memcpy(buf, ident, 32);
len += 32;
buf[len] = routers.size();
len++;
for (const auto &it: routers) {
memcpy(buf + len, it, 32);
len += 32;
}
memcpy(buf + len, i2p::context.GetRouterInfo().GetIdentHash(), 32);
len += 32;
m->len += len;
m->FillI2NPMessageHeader(eI2NPDatabaseSearchReply);
return m;
}
std::shared_ptr<I2NPMessage> CreateDatabaseStoreMsg(std::shared_ptr<const i2p::data::RouterInfo> router,
uint32_t replyToken,
std::shared_ptr<const i2p::tunnel::InboundTunnel> replyTunnel) {
if (!router) // we send own RouterInfo
router = context.GetSharedRouterInfo();
if (!router->GetBuffer()) {
LogPrint(eLogError, "I2NP: Invalid RouterInfo buffer for DatabaseStore");
return nullptr;
}
auto m = NewI2NPShortMessage();
uint8_t *payload = m->GetPayload();
memcpy(payload + DATABASE_STORE_KEY_OFFSET, router->GetIdentHash(), 32);
payload[DATABASE_STORE_TYPE_OFFSET] = 0; // RouterInfo
htobe32buf(payload + DATABASE_STORE_REPLY_TOKEN_OFFSET, replyToken);
uint8_t *buf = payload + DATABASE_STORE_HEADER_SIZE;
if (replyToken) {
if (replyTunnel) {
htobe32buf(buf, replyTunnel->GetNextTunnelID());
buf += 4; // reply tunnelID
memcpy(buf, replyTunnel->GetNextIdentHash(), 32);
buf += 32; // reply tunnel gateway
} else {
memset(buf, 0, 4); // zero tunnelID means direct reply
buf += 4;
memcpy(buf, context.GetIdentHash(), 32);
buf += 32;
}
}
uint8_t *sizePtr = buf;
buf += 2;
m->len += (buf - payload); // payload size
size_t size = 0;
if (router->GetBufferLen() + (buf - payload) <= 940) // fits one tunnel message
size = i2p::data::GzipNoCompression(router->GetBuffer(), router->GetBufferLen(), buf, m->maxLen - m->len);
else {
i2p::data::GzipDeflator deflator;
size = deflator.Deflate(router->GetBuffer(), router->GetBufferLen(), buf, m->maxLen - m->len);
}
if (size) {
htobe16buf(sizePtr, size); // size
m->len += size;
} else
m = nullptr;
if (m)
m->FillI2NPMessageHeader(eI2NPDatabaseStore);
return m;
}
std::shared_ptr<I2NPMessage>
CreateDatabaseStoreMsg(const i2p::data::IdentHash &storeHash, std::shared_ptr<const i2p::data::LeaseSet> leaseSet) {
if (!leaseSet) return nullptr;
auto m = NewI2NPShortMessage();
uint8_t *payload = m->GetPayload();
memcpy(payload + DATABASE_STORE_KEY_OFFSET, storeHash, 32);
payload[DATABASE_STORE_TYPE_OFFSET] = leaseSet->GetStoreType(); // 1 for LeaseSet
htobe32buf(payload + DATABASE_STORE_REPLY_TOKEN_OFFSET, 0);
size_t size = DATABASE_STORE_HEADER_SIZE;
memcpy(payload + size, leaseSet->GetBuffer(), leaseSet->GetBufferLen());
size += leaseSet->GetBufferLen();
m->len += size;
m->FillI2NPMessageHeader(eI2NPDatabaseStore);
return m;
}
std::shared_ptr<I2NPMessage>
CreateDatabaseStoreMsg(std::shared_ptr<const i2p::data::LocalLeaseSet> leaseSet, uint32_t replyToken,
std::shared_ptr<const i2p::tunnel::InboundTunnel> replyTunnel) {
if (!leaseSet) return nullptr;
auto m = NewI2NPShortMessage();
uint8_t *payload = m->GetPayload();
memcpy(payload + DATABASE_STORE_KEY_OFFSET, leaseSet->GetStoreHash(), 32);
payload[DATABASE_STORE_TYPE_OFFSET] = leaseSet->GetStoreType(); // LeaseSet or LeaseSet2
htobe32buf(payload + DATABASE_STORE_REPLY_TOKEN_OFFSET, replyToken);
size_t size = DATABASE_STORE_HEADER_SIZE;
if (replyToken && replyTunnel) {
if (replyTunnel) {
htobe32buf(payload + size, replyTunnel->GetNextTunnelID());
size += 4; // reply tunnelID
memcpy(payload + size, replyTunnel->GetNextIdentHash(), 32);
size += 32; // reply tunnel gateway
} else
htobe32buf(payload + DATABASE_STORE_REPLY_TOKEN_OFFSET, 0);
}
memcpy(payload + size, leaseSet->GetBuffer(), leaseSet->GetBufferLen());
size += leaseSet->GetBufferLen();
m->len += size;
m->FillI2NPMessageHeader(eI2NPDatabaseStore);
return m;
}
bool IsRouterInfoMsg(std::shared_ptr<I2NPMessage> msg) {
if (!msg || msg->GetTypeID() != eI2NPDatabaseStore) return false;
return !msg->GetPayload()[DATABASE_STORE_TYPE_OFFSET]; // 0- RouterInfo
}
static uint16_t g_MaxNumTransitTunnels = DEFAULT_MAX_NUM_TRANSIT_TUNNELS; // TODO:
void SetMaxNumTransitTunnels(uint16_t maxNumTransitTunnels) {
if (maxNumTransitTunnels > 0 && g_MaxNumTransitTunnels != maxNumTransitTunnels) {
LogPrint(eLogDebug, "I2NP: Max number of transit tunnels set to ", maxNumTransitTunnels);
g_MaxNumTransitTunnels = maxNumTransitTunnels;
}
}
uint16_t GetMaxNumTransitTunnels() {
return g_MaxNumTransitTunnels;
}
static bool HandleBuildRequestRecords(int num, uint8_t *records, uint8_t *clearText) {
for (int i = 0; i < num; i++) {
uint8_t *record = records + i * TUNNEL_BUILD_RECORD_SIZE;
if (!memcmp(record + BUILD_REQUEST_RECORD_TO_PEER_OFFSET,
(const uint8_t *) i2p::context.GetRouterInfo().GetIdentHash(), 16)) {
LogPrint(eLogDebug, "I2NP: Build request record ", i, " is ours");
if (!i2p::context.DecryptTunnelBuildRecord(record + BUILD_REQUEST_RECORD_ENCRYPTED_OFFSET,
clearText))
return false;
uint8_t retCode = 0;
// replace record to reply
if (i2p::context.AcceptsTunnels() &&
i2p::tunnel::tunnels.GetTransitTunnels().size() <= g_MaxNumTransitTunnels &&
!i2p::transport::transports.IsBandwidthExceeded() &&
!i2p::transport::transports.IsTransitBandwidthExceeded()) {
auto transitTunnel = i2p::tunnel::CreateTransitTunnel(
bufbe32toh(clearText + ECIES_BUILD_REQUEST_RECORD_RECEIVE_TUNNEL_OFFSET),
clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_IDENT_OFFSET,
bufbe32toh(clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_TUNNEL_OFFSET),
clearText + ECIES_BUILD_REQUEST_RECORD_LAYER_KEY_OFFSET,
clearText + ECIES_BUILD_REQUEST_RECORD_IV_KEY_OFFSET,
clearText[ECIES_BUILD_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_GATEWAY_FLAG,
clearText[ECIES_BUILD_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_ENDPOINT_FLAG);
i2p::tunnel::tunnels.AddTransitTunnel(transitTunnel);
} else
retCode = 30; // always reject with bandwidth reason (30)
memset(record + ECIES_BUILD_RESPONSE_RECORD_OPTIONS_OFFSET, 0, 2); // no options
record[ECIES_BUILD_RESPONSE_RECORD_RET_OFFSET] = retCode;
// encrypt reply
i2p::crypto::CBCEncryption encryption;
for (int j = 0; j < num; j++) {
uint8_t *reply = records + j * TUNNEL_BUILD_RECORD_SIZE;
if (j == i) {
uint8_t nonce[12];
memset(nonce, 0, 12);
auto &noiseState = i2p::context.GetCurrentNoiseState();
if (!i2p::crypto::AEADChaCha20Poly1305(reply, TUNNEL_BUILD_RECORD_SIZE - 16,
noiseState.m_H, 32, noiseState.m_CK, nonce, reply,
TUNNEL_BUILD_RECORD_SIZE, true)) // encrypt
{
LogPrint(eLogWarning, "I2NP: Reply AEAD encryption failed");
return false;
}
} else {
encryption.SetKey(clearText + ECIES_BUILD_REQUEST_RECORD_REPLY_KEY_OFFSET);
encryption.SetIV(clearText + ECIES_BUILD_REQUEST_RECORD_REPLY_IV_OFFSET);
encryption.Encrypt(reply, TUNNEL_BUILD_RECORD_SIZE, reply);
}
}
return true;
}
}
return false;
}
static void HandleVariableTunnelBuildMsg(uint32_t replyMsgID, uint8_t *buf, size_t len) {
int num = buf[0];
LogPrint(eLogDebug, "I2NP: VariableTunnelBuild ", num, " records");
if (len < num * TUNNEL_BUILD_RECORD_SIZE + 1) {
LogPrint(eLogError, "I2NP: VaribleTunnelBuild message of ", num, " records is too short ", len);
return;
}
auto tunnel = i2p::tunnel::tunnels.GetPendingInboundTunnel(replyMsgID);
if (tunnel) {
// endpoint of inbound tunnel
LogPrint(eLogDebug, "I2NP: VariableTunnelBuild reply for tunnel ", tunnel->GetTunnelID());
if (tunnel->HandleTunnelBuildResponse(buf, len)) {
LogPrint(eLogInfo, "I2NP: Inbound tunnel ", tunnel->GetTunnelID(), " has been created");
tunnel->SetState(i2p::tunnel::eTunnelStateEstablished);
i2p::tunnel::tunnels.AddInboundTunnel(tunnel);
} else {
LogPrint(eLogInfo, "I2NP: Inbound tunnel ", tunnel->GetTunnelID(), " has been declined");
tunnel->SetState(i2p::tunnel::eTunnelStateBuildFailed);
}
} else {
uint8_t clearText[ECIES_BUILD_REQUEST_RECORD_CLEAR_TEXT_SIZE];
if (HandleBuildRequestRecords(num, buf + 1, clearText)) {
if (clearText[ECIES_BUILD_REQUEST_RECORD_FLAG_OFFSET] &
TUNNEL_BUILD_RECORD_ENDPOINT_FLAG) // we are endpoint of outboud tunnel
{
// so we send it to reply tunnel
transports.SendMessage(clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_IDENT_OFFSET,
CreateTunnelGatewayMsg(bufbe32toh(
clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_TUNNEL_OFFSET),
eI2NPVariableTunnelBuildReply, buf, len,
bufbe32toh(clearText +
ECIES_BUILD_REQUEST_RECORD_SEND_MSG_ID_OFFSET)));
} else
transports.SendMessage(clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_IDENT_OFFSET,
CreateI2NPMessage(eI2NPVariableTunnelBuild, buf, len,
bufbe32toh(clearText +
ECIES_BUILD_REQUEST_RECORD_SEND_MSG_ID_OFFSET)));
}
}
}
static void HandleTunnelBuildMsg(uint8_t *buf, size_t len) {
LogPrint(eLogWarning, "I2NP: TunnelBuild is too old for ECIES router");
}
static void HandleTunnelBuildReplyMsg(uint32_t replyMsgID, uint8_t *buf, size_t len, bool isShort) {
int num = buf[0];
LogPrint(eLogDebug, "I2NP: TunnelBuildReplyMsg of ", num, " records replyMsgID=", replyMsgID);
size_t recordSize = isShort ? SHORT_TUNNEL_BUILD_RECORD_SIZE : TUNNEL_BUILD_RECORD_SIZE;
if (len < num * recordSize + 1) {
LogPrint(eLogError, "I2NP: TunnelBuildReply message of ", num, " records is too short ", len);
return;
}
auto tunnel = i2p::tunnel::tunnels.GetPendingOutboundTunnel(replyMsgID);
if (tunnel) {
// reply for outbound tunnel
if (tunnel->HandleTunnelBuildResponse(buf, len)) {
LogPrint(eLogInfo, "I2NP: Outbound tunnel ", tunnel->GetTunnelID(), " has been created");
tunnel->SetState(i2p::tunnel::eTunnelStateEstablished);
i2p::tunnel::tunnels.AddOutboundTunnel(tunnel);
} else {
LogPrint(eLogInfo, "I2NP: Outbound tunnel ", tunnel->GetTunnelID(), " has been declined");
tunnel->SetState(i2p::tunnel::eTunnelStateBuildFailed);
}
} else
LogPrint(eLogWarning, "I2NP: Pending tunnel for message ", replyMsgID, " not found");
}
static void HandleShortTunnelBuildMsg(uint32_t replyMsgID, uint8_t *buf, size_t len) {
int num = buf[0];
LogPrint(eLogDebug, "I2NP: ShortTunnelBuild ", num, " records");
if (len < num * SHORT_TUNNEL_BUILD_RECORD_SIZE + 1) {
LogPrint(eLogError, "I2NP: ShortTunnelBuild message of ", num, " records is too short ", len);
return;
}
auto tunnel = i2p::tunnel::tunnels.GetPendingInboundTunnel(replyMsgID);
if (tunnel) {
// endpoint of inbound tunnel
LogPrint(eLogDebug, "I2NP: ShortTunnelBuild reply for tunnel ", tunnel->GetTunnelID());
if (tunnel->HandleTunnelBuildResponse(buf, len)) {
LogPrint(eLogInfo, "I2NP: Inbound tunnel ", tunnel->GetTunnelID(), " has been created");
tunnel->SetState(i2p::tunnel::eTunnelStateEstablished);
i2p::tunnel::tunnels.AddInboundTunnel(tunnel);
} else {
LogPrint(eLogInfo, "I2NP: Inbound tunnel ", tunnel->GetTunnelID(), " has been declined");
tunnel->SetState(i2p::tunnel::eTunnelStateBuildFailed);
}
return;
}
const uint8_t *record = buf + 1;
for (int i = 0; i < num; i++) {
if (!memcmp(record, (const uint8_t *) i2p::context.GetRouterInfo().GetIdentHash(), 16)) {
LogPrint(eLogDebug, "I2NP: Short request record ", i, " is ours");
uint8_t clearText[SHORT_REQUEST_RECORD_CLEAR_TEXT_SIZE];
if (!i2p::context.DecryptTunnelShortRequestRecord(record + SHORT_REQUEST_RECORD_ENCRYPTED_OFFSET,
clearText)) {
LogPrint(eLogWarning, "I2NP: Can't decrypt short request record ", i);
return;
}
if (clearText[SHORT_REQUEST_RECORD_LAYER_ENCRYPTION_TYPE]) // not AES
{
LogPrint(eLogWarning, "I2NP: Unknown layer encryption type ",
clearText[SHORT_REQUEST_RECORD_LAYER_ENCRYPTION_TYPE], " in short request record");
return;
}
auto &noiseState = i2p::context.GetCurrentNoiseState();
uint8_t replyKey[32], layerKey[32], ivKey[32];
i2p::crypto::HKDF(noiseState.m_CK, nullptr, 0, "SMTunnelReplyKey", noiseState.m_CK);
memcpy(replyKey, noiseState.m_CK + 32, 32);
i2p::crypto::HKDF(noiseState.m_CK, nullptr, 0, "SMTunnelLayerKey", noiseState.m_CK);
memcpy(layerKey, noiseState.m_CK + 32, 32);
bool isEndpoint = clearText[SHORT_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_ENDPOINT_FLAG;
if (isEndpoint) {
i2p::crypto::HKDF(noiseState.m_CK, nullptr, 0, "TunnelLayerIVKey", noiseState.m_CK);
memcpy(ivKey, noiseState.m_CK + 32, 32);
} else
memcpy(ivKey, noiseState.m_CK, 32);
// check if we accept this tunnel
uint8_t retCode = 0;
if (!i2p::context.AcceptsTunnels() ||
i2p::tunnel::tunnels.GetTransitTunnels().size() > g_MaxNumTransitTunnels ||
i2p::transport::transports.IsBandwidthExceeded() ||
i2p::transport::transports.IsTransitBandwidthExceeded())
retCode = 30;
if (!retCode) {
// create new transit tunnel
auto transitTunnel = i2p::tunnel::CreateTransitTunnel(
bufbe32toh(clearText + SHORT_REQUEST_RECORD_RECEIVE_TUNNEL_OFFSET),
clearText + SHORT_REQUEST_RECORD_NEXT_IDENT_OFFSET,
bufbe32toh(clearText + SHORT_REQUEST_RECORD_NEXT_TUNNEL_OFFSET),
layerKey, ivKey,
clearText[SHORT_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_GATEWAY_FLAG,
clearText[SHORT_REQUEST_RECORD_FLAG_OFFSET] & TUNNEL_BUILD_RECORD_ENDPOINT_FLAG);
i2p::tunnel::tunnels.AddTransitTunnel(transitTunnel);
}
// encrypt reply
uint8_t nonce[12];
memset(nonce, 0, 12);
uint8_t *reply = buf + 1;
for (int j = 0; j < num; j++) {
nonce[4] = j; // nonce is record #
if (j == i) {
memset(reply + SHORT_RESPONSE_RECORD_OPTIONS_OFFSET, 0, 2); // no options
reply[SHORT_RESPONSE_RECORD_RET_OFFSET] = retCode;
if (!i2p::crypto::AEADChaCha20Poly1305(reply, SHORT_TUNNEL_BUILD_RECORD_SIZE - 16,
noiseState.m_H, 32, replyKey, nonce, reply,
SHORT_TUNNEL_BUILD_RECORD_SIZE, true)) // encrypt
{
LogPrint(eLogWarning, "I2NP: Short reply AEAD encryption failed");
return;
}
} else
i2p::crypto::ChaCha20(reply, SHORT_TUNNEL_BUILD_RECORD_SIZE, replyKey, nonce, reply);
reply += SHORT_TUNNEL_BUILD_RECORD_SIZE;
}
// send reply
if (isEndpoint) {
auto replyMsg = NewI2NPShortMessage();
replyMsg->Concat(buf, len);
replyMsg->FillI2NPMessageHeader(eI2NPShortTunnelBuildReply,
bufbe32toh(clearText + SHORT_REQUEST_RECORD_SEND_MSG_ID_OFFSET));
if (memcmp((const uint8_t *) i2p::context.GetIdentHash(),
clearText + SHORT_REQUEST_RECORD_NEXT_IDENT_OFFSET, 32)) // reply IBGW is not local?
{
i2p::crypto::HKDF(noiseState.m_CK, nullptr, 0, "RGarlicKeyAndTag", noiseState.m_CK);
uint64_t tag;
memcpy(&tag, noiseState.m_CK, 8);
// we send it to reply tunnel
transports.SendMessage(clearText + SHORT_REQUEST_RECORD_NEXT_IDENT_OFFSET,
CreateTunnelGatewayMsg(
bufbe32toh(clearText + SHORT_REQUEST_RECORD_NEXT_TUNNEL_OFFSET),
i2p::garlic::WrapECIESX25519Message(replyMsg,
noiseState.m_CK + 32, tag)));
} else {
// IBGW is local
uint32_t tunnelID = bufbe32toh(clearText + SHORT_REQUEST_RECORD_NEXT_TUNNEL_OFFSET);
auto tunnel = i2p::tunnel::tunnels.GetTunnel(tunnelID);
if (tunnel)
tunnel->SendTunnelDataMsg(replyMsg);
else
LogPrint(eLogWarning, "I2NP: Tunnel ", tunnelID, " not found for short tunnel build reply");
}
} else
transports.SendMessage(clearText + SHORT_REQUEST_RECORD_NEXT_IDENT_OFFSET,
CreateI2NPMessage(eI2NPShortTunnelBuild, buf, len,
bufbe32toh(clearText +
SHORT_REQUEST_RECORD_SEND_MSG_ID_OFFSET)));
return;
}
record += SHORT_TUNNEL_BUILD_RECORD_SIZE;
}
}
std::shared_ptr<I2NPMessage> CreateTunnelDataMsg(const uint8_t *buf) {
auto msg = NewI2NPTunnelMessage(false);
msg->Concat(buf, i2p::tunnel::TUNNEL_DATA_MSG_SIZE);
msg->FillI2NPMessageHeader(eI2NPTunnelData);
return msg;
}
std::shared_ptr<I2NPMessage> CreateTunnelDataMsg(uint32_t tunnelID, const uint8_t *payload) {
auto msg = NewI2NPTunnelMessage(false);
htobe32buf(msg->GetPayload(), tunnelID);
msg->len += 4; // tunnelID
msg->Concat(payload, i2p::tunnel::TUNNEL_DATA_MSG_SIZE - 4);
msg->FillI2NPMessageHeader(eI2NPTunnelData);
return msg;
}
std::shared_ptr<I2NPMessage> CreateEmptyTunnelDataMsg(bool endpoint) {
auto msg = NewI2NPTunnelMessage(endpoint);
msg->len += i2p::tunnel::TUNNEL_DATA_MSG_SIZE;
return msg;
}
std::shared_ptr<I2NPMessage> CreateTunnelGatewayMsg(uint32_t tunnelID, const uint8_t *buf, size_t len) {
auto msg = NewI2NPMessage(len);
uint8_t *payload = msg->GetPayload();
htobe32buf(payload + TUNNEL_GATEWAY_HEADER_TUNNELID_OFFSET, tunnelID);
htobe16buf(payload + TUNNEL_GATEWAY_HEADER_LENGTH_OFFSET, len);
msg->len += TUNNEL_GATEWAY_HEADER_SIZE;
if (msg->Concat(buf, len) < len)
LogPrint(eLogError, "I2NP: Tunnel gateway buffer overflow ", msg->maxLen);
msg->FillI2NPMessageHeader(eI2NPTunnelGateway);
return msg;
}
std::shared_ptr<I2NPMessage> CreateTunnelGatewayMsg(uint32_t tunnelID, std::shared_ptr<I2NPMessage> msg) {
if (msg->offset >= I2NP_HEADER_SIZE + TUNNEL_GATEWAY_HEADER_SIZE) {
// message is capable to be used without copying
uint8_t *payload = msg->GetBuffer() - TUNNEL_GATEWAY_HEADER_SIZE;
htobe32buf(payload + TUNNEL_GATEWAY_HEADER_TUNNELID_OFFSET, tunnelID);
int len = msg->GetLength();
htobe16buf(payload + TUNNEL_GATEWAY_HEADER_LENGTH_OFFSET, len);
msg->offset -= (I2NP_HEADER_SIZE + TUNNEL_GATEWAY_HEADER_SIZE);
msg->len = msg->offset + I2NP_HEADER_SIZE + TUNNEL_GATEWAY_HEADER_SIZE + len;
msg->FillI2NPMessageHeader(eI2NPTunnelGateway);
return msg;
} else
return CreateTunnelGatewayMsg(tunnelID, msg->GetBuffer(), msg->GetLength());
}
std::shared_ptr<I2NPMessage> CreateTunnelGatewayMsg(uint32_t tunnelID, I2NPMessageType msgType,
const uint8_t *buf, size_t len, uint32_t replyMsgID) {
auto msg = NewI2NPMessage(len);
size_t gatewayMsgOffset = I2NP_HEADER_SIZE + TUNNEL_GATEWAY_HEADER_SIZE;
msg->offset += gatewayMsgOffset;
msg->len += gatewayMsgOffset;
if (msg->Concat(buf, len) < len)
LogPrint(eLogError, "I2NP: Tunnel gateway buffer overflow ", msg->maxLen);
msg->FillI2NPMessageHeader(msgType, replyMsgID); // create content message
len = msg->GetLength();
msg->offset -= gatewayMsgOffset;
uint8_t *payload = msg->GetPayload();
htobe32buf(payload + TUNNEL_GATEWAY_HEADER_TUNNELID_OFFSET, tunnelID);
htobe16buf(payload + TUNNEL_GATEWAY_HEADER_LENGTH_OFFSET, len);
msg->FillI2NPMessageHeader(eI2NPTunnelGateway); // gateway message
return msg;
}
size_t GetI2NPMessageLength(const uint8_t *msg, size_t len) {
if (len < I2NP_HEADER_SIZE_OFFSET + 2) {
LogPrint(eLogError, "I2NP: Message length ", len, " is smaller than header");
return len;
}
auto l = bufbe16toh(msg + I2NP_HEADER_SIZE_OFFSET) + I2NP_HEADER_SIZE;
if (l > len) {
LogPrint(eLogError, "I2NP: Message length ", l, " exceeds buffer length ", len);
l = len;
}
return l;
}
void HandleI2NPMessage(uint8_t *msg, size_t len) {
if (len < I2NP_HEADER_SIZE) {
LogPrint(eLogError, "I2NP: Message length ", len, " is smaller than header");
return;
}
uint8_t typeID = msg[I2NP_HEADER_TYPEID_OFFSET];
uint32_t msgID = bufbe32toh(msg + I2NP_HEADER_MSGID_OFFSET);
LogPrint(eLogDebug, "I2NP: Msg received len=", len, ", type=", (int) typeID, ", msgID=", (unsigned int) msgID);
uint8_t *buf = msg + I2NP_HEADER_SIZE;
auto size = bufbe16toh(msg + I2NP_HEADER_SIZE_OFFSET);
len -= I2NP_HEADER_SIZE;
if (size > len) {
LogPrint(eLogError, "I2NP: Payload size ", size, " exceeds buffer length ", len);
size = len;
}
switch (typeID) {
case eI2NPVariableTunnelBuild:
HandleVariableTunnelBuildMsg(msgID, buf, size);
break;
case eI2NPShortTunnelBuild:
HandleShortTunnelBuildMsg(msgID, buf, size);
break;
case eI2NPVariableTunnelBuildReply:
HandleTunnelBuildReplyMsg(msgID, buf, size, false);
break;
case eI2NPShortTunnelBuildReply:
HandleTunnelBuildReplyMsg(msgID, buf, size, true);
break;
case eI2NPTunnelBuild:
HandleTunnelBuildMsg(buf, size);
break;
case eI2NPTunnelBuildReply:
// TODO:
break;
default:
LogPrint(eLogWarning, "I2NP: Unexpected message ", (int) typeID);
}
}
void HandleI2NPMessage(std::shared_ptr<I2NPMessage> msg) {
if (msg) {
uint8_t typeID = msg->GetTypeID();
LogPrint(eLogDebug, "I2NP: Handling message with type ", (int) typeID);
switch (typeID) {
case eI2NPTunnelData:
i2p::tunnel::tunnels.PostTunnelData(msg);
break;
case eI2NPTunnelGateway:
i2p::tunnel::tunnels.PostTunnelData(msg);
break;
case eI2NPGarlic: {
if (msg->from && msg->from->GetTunnelPool())
msg->from->GetTunnelPool()->ProcessGarlicMessage(msg);
else
i2p::context.ProcessGarlicMessage(msg);
break;
}
case eI2NPDatabaseStore:
case eI2NPDatabaseSearchReply:
case eI2NPDatabaseLookup:
// forward to netDb
i2p::data::netdb.PostI2NPMsg(msg);
break;
case eI2NPDeliveryStatus: {
if (msg->from && msg->from->GetTunnelPool())
msg->from->GetTunnelPool()->ProcessDeliveryStatus(msg);
else
i2p::context.ProcessDeliveryStatusMessage(msg);
break;
}
case eI2NPVariableTunnelBuild:
case eI2NPVariableTunnelBuildReply:
case eI2NPTunnelBuild:
case eI2NPTunnelBuildReply:
case eI2NPShortTunnelBuild:
case eI2NPShortTunnelBuildReply:
// forward to tunnel thread
i2p::tunnel::tunnels.PostTunnelData(msg);
break;
default:
HandleI2NPMessage(msg->GetBuffer(), msg->GetLength());
}
}
}
I2NPMessagesHandler::~I2NPMessagesHandler() {
Flush();
}
void I2NPMessagesHandler::PutNextMessage(std::shared_ptr<I2NPMessage> &&msg) {
if (msg) {
switch (msg->GetTypeID()) {
case eI2NPTunnelData:
m_TunnelMsgs.push_back(msg);
break;
case eI2NPTunnelGateway:
m_TunnelGatewayMsgs.push_back(msg);
break;
default:
HandleI2NPMessage(msg);
}
}
}
void I2NPMessagesHandler::Flush() {
if (!m_TunnelMsgs.empty()) {
i2p::tunnel::tunnels.PostTunnelData(m_TunnelMsgs);
m_TunnelMsgs.clear();
}
if (!m_TunnelGatewayMsgs.empty()) {
i2p::tunnel::tunnels.PostTunnelData(m_TunnelGatewayMsgs);
m_TunnelGatewayMsgs.clear();
}
}
}
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