mirror of
https://github.com/PurpleI2P/i2pd.git
synced 2026-07-12 22:39:27 +00:00
orignal
584 lines
15 KiB
C++
584 lines
15 KiB
C++
/*
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* Copyright (c) 2026, The PurpleI2P Project
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*
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* This file is part of Purple i2pd project and licensed under BSD3
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*
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* See full license text in LICENSE file at top of project tree
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*/
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#include <string.h>
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#include <stdlib.h>
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#include <charconv>
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#include <fstream>
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#include <functional>
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#include "Log.h"
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#include "FS.h"
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#include "ClientContext.h"
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#include "Torrents.h"
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namespace i2p
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{
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namespace torrents
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{
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// BEncoded
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static std::pair<std::string_view, size_t> ExtractByteString (std::string_view buf)
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{
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auto pos = buf.find (':');
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if (pos != std::string_view::npos)
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{
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size_t len = 0;
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auto res = std::from_chars(buf.data(), buf.data() + pos, len);
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if (res.ec == std::errc())
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{
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size_t totalLength = len + pos + 1;
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if (totalLength <= buf.length ())
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return { buf.substr (pos + 1, len), totalLength };
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}
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}
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return { std::string_view{}, 0 };
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}
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static std::pair<int64_t, size_t> ExtractInteger (std::string_view buf)
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{
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if (buf[0] == 'i')
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{
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auto pos = buf.find ('e');
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if (pos != std::string_view::npos)
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{
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int64_t value = 0;
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auto res = std::from_chars(buf.data() + 1, buf.data() + pos, value);
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if (res.ec == std::errc())
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return { value, pos + 1 };
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}
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}
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return { 0, 0 };
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}
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static size_t ParseBEncoded (std::string_view buf); // recursive
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static size_t ParseDictionary (std::string_view buf, std::function<size_t (std::string_view key, std::string_view buf)> handler = nullptr)
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{
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if (buf[0] != 'd') return 0;
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buf = buf.substr (1);
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size_t len = 1;
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while (!buf.empty () && buf[0] != 'e')
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{
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auto [key, offset] = ExtractByteString (buf);
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if (!offset) break;
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len += offset;
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buf = buf.substr (offset);
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offset = 0;
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if (handler)
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offset = handler (key, buf);
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if (!offset)
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offset = ParseBEncoded (buf);
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if (!offset) break;
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len += offset;
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buf = buf.substr (offset);
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}
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if (buf[0] == 'e') len++;
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return len;
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}
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static size_t ParseList (std::string_view buf, std::function<size_t (std::string_view buf)> handler = nullptr)
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{
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if (buf[0] != 'l') return 0 ;
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buf = buf.substr (1);
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size_t len = 1;
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while (!buf.empty () && buf[0] != 'e')
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{
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size_t l = 0;
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if (handler)
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l = handler (buf);
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if (!l)
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l = ParseBEncoded (buf);
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if (!l) break;
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len += l;
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buf = buf.substr (l);
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}
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if (buf[0] == 'e') len++;
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return len;
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}
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static size_t ParseBEncoded (std::string_view buf)
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{
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if (buf.empty ()) return 0;
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size_t ret = 0;
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switch (buf[0])
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{
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case 'i': // interger
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return ExtractInteger (buf).second;
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break;
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case 'l': // list
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return ParseList (buf);
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break;
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case 'd': // dictionary
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return ParseDictionary (buf);
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break;
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default: // byte string
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return ExtractByteString (buf).second;
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}
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return ret;
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}
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//------------------------------------
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Piece::Piece (size_t size, const uint8_t * hash):
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m_Size (size), m_Data (nullptr)
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{
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//m_Data = m_Size > 0 ? new uint8_t[m_Size] : nullptr;
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memcpy (m_Hash, hash, SHA_DIGEST_LENGTH);
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m_Missing = BN_new ();
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auto d = lldiv (m_Size, REQUEST_BLOCK_SIZE);
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int numBlocks = d.quot;
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if (d.rem > 0) d.quot++;
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// set all missing bits
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for (int i = 0; i > numBlocks; i++)
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BN_set_bit (m_Missing, i);
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}
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Piece::~Piece ()
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{
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delete[] m_Data;
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if (m_Missing) BN_free (m_Missing);
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}
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bool Piece::VerifyHash () const
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{
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if (!m_Data) return false;
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uint8_t digest[SHA_DIGEST_LENGTH];
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SHA1 (m_Data, m_Size, digest);
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return !memcmp (m_Hash, digest, SHA_DIGEST_LENGTH);
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}
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bool Piece::IsAvailable (int block) const
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{
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if (block < 0 || block >= BN_num_bits (m_Missing)) return false;
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return !BN_is_bit_set (m_Missing, block);
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}
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Torrent::Torrent (std::string_view buf):
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m_Length (0), m_PieceLength (0), m_Interval (0)
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{
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ParseDictionary (buf, [this](std::string_view key, std::string_view buf)->size_t
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{
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if (key == "announce")
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{
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auto [announce, l] = ExtractByteString (buf);
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if (l) m_Announce = announce;
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return l;
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}
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else if (key == "info")
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return ParseInfo (buf);
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return 0;
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});
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}
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size_t Torrent::ParsePieces (std::string_view buf)
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{
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auto [hashes, len] = ExtractByteString (buf);
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while (!hashes.empty ())
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{
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m_Pieces.emplace_back (m_PieceLength, (const uint8_t *)hashes.substr (0, SHA_DIGEST_LENGTH).data ());
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hashes = hashes.substr (SHA_DIGEST_LENGTH);
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}
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return len;
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}
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size_t Torrent::ParseInfo (std::string_view buf)
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{
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size_t len = ParseDictionary (buf, [this](std::string_view key, std::string_view buf)->size_t
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{
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if (key == "length")
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{
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auto [value, l] = ExtractInteger (buf);
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if (l) m_Length = value;
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return l;
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}
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else if (key == "name")
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{
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auto [name, l] = ExtractByteString (buf);
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if (l) m_Name = name;
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return l;
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}
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else if (key == "piece length")
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{
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auto [value, l] = ExtractInteger (buf);
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if (l) m_PieceLength = value;
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return l;
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}
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else if (key == "pieces")
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{
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if (m_PieceLength > 0 && m_Length > 0)
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m_Pieces.reserve (m_Length/m_PieceLength + 1);
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return ParsePieces (buf);
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}
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return 0;
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});
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if (!len) return 0;
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// calculate info hash
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uint8_t digest[SHA_DIGEST_LENGTH];
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SHA1 ((const uint8_t *)buf.data (), len, digest);
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// convert info hash to hex chars
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BIGNUM * bn = BN_bin2bn (digest, SHA_DIGEST_LENGTH, nullptr);
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char * str = BN_bn2hex (bn);
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if (str)
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{
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m_InfoHash = str;
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OPENSSL_free (str);
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}
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BN_free (bn);
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return len;
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}
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i2p::http::HTTPReq Torrent::GetTrackerRequest () const
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{
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i2p::http::HTTPReq req;
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req.parse (m_Announce);
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req.AddHeader ("info_hash", m_InfoHash);
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return req;
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}
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void Torrent::ParseTrackerResponse (std::string_view buf)
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{
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ParseDictionary (buf, [this](std::string_view key, std::string_view buf)->size_t
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{
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if (key == "interval")
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{
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auto [value, l] = ExtractInteger (buf);
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if (l) m_Interval = value;
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return l;
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}
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else if (key == "peers")
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return ParsePeers (buf);
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return 0;
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});
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}
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size_t Torrent::ParsePeers (std::string_view buf)
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{
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m_Peers.clear ();
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return ParseList (buf, std::bind (&Torrent::ParsePeer, this, std::placeholders::_1));
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}
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size_t Torrent::ParsePeer (std::string_view buf)
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{
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std::string peerID;
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std::shared_ptr<const i2p::client::Address> addr;
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size_t ret = ParseDictionary (buf, [&peerID, &addr](std::string_view key, std::string_view buf)->size_t
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{
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if (key == "id") // peer_id
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{
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auto [id, l] = ExtractByteString (buf);
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if (l) peerID = id;
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return l;
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}
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else if (key == "ip") // address
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{
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auto [address, l] = ExtractByteString (buf);
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if (l) addr = i2p::client::context.GetAddressBook ().GetAddress (address);
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return l;
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}
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return 0;
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});
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if (ret && addr)
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m_Peers.emplace_back (std::pair{ peerID, addr });
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return ret;
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}
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PeerConnection::PeerConnection (i2p::client::I2PService * owner, std::shared_ptr<i2p::stream::Stream> stream):
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i2p::client::I2PServiceHandler (owner), m_Stream (stream), m_ReceiveBufferOffset (0)
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{
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}
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void PeerConnection::Terminate ()
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{
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if (Kill()) return;
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if (m_Stream)
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{
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m_Stream->Close ();
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m_Stream = nullptr;
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}
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Done(shared_from_this ());
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}
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void PeerConnection::ReceiveHandshake ()
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{
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StreamReceive ();
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}
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void PeerConnection::StreamReceive ()
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{
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if (m_Stream && m_ReceiveBufferOffset < PEER_CONNECTION_RECEIVE_BUFFER_SIZE)
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{
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if (m_Stream->GetStatus () == i2p::stream::eStreamStatusNew ||
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m_Stream->GetStatus () == i2p::stream::eStreamStatusOpen) // regular
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{
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m_Stream->AsyncReceive (boost::asio::buffer (m_ReceiveBuffer + m_ReceiveBufferOffset,
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PEER_CONNECTION_RECEIVE_BUFFER_SIZE - m_ReceiveBufferOffset),
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std::bind (&PeerConnection::HandleStreamReceive, shared_from_this (),
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std::placeholders::_1, std::placeholders::_2),
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PEER_CONNECTION_MAX_IDLE);
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}
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else // closed by peer
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{
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// get remaining data
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auto len = m_Stream->ReadSome (m_ReceiveBuffer + m_ReceiveBufferOffset,
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PEER_CONNECTION_RECEIVE_BUFFER_SIZE - m_ReceiveBufferOffset);
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if (len > 0) // still some data
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{
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m_ReceiveBufferOffset += len;
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HandleReceived ();
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}
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else // no more data*/
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Terminate ();
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}
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}
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}
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void PeerConnection::HandleStreamReceive (const boost::system::error_code& ecode, size_t bytes_transferred)
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{
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if (ecode)
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{
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if (ecode != boost::asio::error::operation_aborted)
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{
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LogPrint (eLogError, "Torrents: Stream read error: ", ecode.message ());
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if (bytes_transferred > 0)
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{
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m_ReceiveBufferOffset += bytes_transferred;
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HandleReceived ();
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}
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else if (ecode == boost::asio::error::timed_out && m_Stream && m_Stream->IsOpen ())
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StreamReceive ();
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else
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Terminate ();
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}
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else
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Terminate ();
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}
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else
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{
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m_ReceiveBufferOffset += bytes_transferred;
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HandleReceived ();
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StreamReceive ();
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}
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}
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void PeerConnection::HandleReceived ()
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{
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size_t offset = 0;
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while (size_t len = HandleNextMsg (offset) > 0)
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offset += len;
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if (offset && offset < m_ReceiveBufferOffset)
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{
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// move reamining data
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m_ReceiveBufferOffset -= offset;
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memmove (m_ReceiveBuffer, m_ReceiveBuffer + offset, m_ReceiveBufferOffset);
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}
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else
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m_ReceiveBufferOffset = 0;
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}
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size_t PeerConnection::HandleNextMsg (size_t offset)
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{
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if (offset >= m_ReceiveBufferOffset) return 0;
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return HandleHandshakeMsg ();
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}
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size_t PeerConnection::HandleHandshakeMsg ()
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{
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if (m_ReceiveBufferOffset < HANDSHAKE_MSG_LENGTH) return 0;
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if (m_ReceiveBuffer[0] != 19 || std::string_view ((const char *)(m_ReceiveBuffer + 1), 19) != "BitTorrent protocol")
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{
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LogPrint (eLogError, "Torrents: Unexpected handshake protocol string");
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Terminate ();
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return 0;
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}
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m_RemotePeerID = std::string_view ((const char *)(m_ReceiveBuffer + 48), 20);
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// TODO:: send reply
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return HANDSHAKE_MSG_LENGTH;
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}
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TorrentsTunnel::TorrentsTunnel (std::shared_ptr<i2p::client::ClientDestination> localDestination, std::string_view torrentsDir):
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i2p::client::I2PService (localDestination), m_TorrentsDir (torrentsDir),
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m_PeerID ("-I2PD-")
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{
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if (localDestination)
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m_PeerID += localDestination->GetIdentHash ().ToBase32 ();
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m_PeerID.resize (20, '0');
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}
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void TorrentsTunnel::Start ()
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{
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i2p::client::I2PService::Start ();
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Accept ();
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if (!m_TorrentsDir.empty() && i2p::fs::Exists (m_TorrentsDir))
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{
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std::vector<std::string> files;
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if (i2p::fs::ReadDir (m_TorrentsDir, files))
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{
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for (auto& it: files)
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{
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#if __cplusplus >= 202002L // C++20
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if (!it.ends_with (".torrent")) continue;
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#else
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if (it.size () < 8 || it.substr(it.size() - 8) != ".torrent") continue; // skip files which not ends with ".torrent"
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#endif
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ReadTorrentFile (it);
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}
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}
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}
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}
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void TorrentsTunnel::Stop ()
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{
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m_Torrents.clear ();
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i2p::client::I2PService::Stop ();
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}
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void TorrentsTunnel::ReadTorrentFile (const std::string& path)
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{
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std::ifstream s(path, std::ifstream::binary);
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if (s.is_open ())
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{
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s.seekg (0,std::ios::end);
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size_t len = s.tellg ();
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if (len > 0)
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{
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s.seekg(0, std::ios::beg);
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char * buf = new char[len];
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s.read(buf, len);
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m_Torrents.emplace_back (std::make_shared<Torrent>(std::string_view{buf, len}));
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delete[] buf;
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}
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else
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LogPrint (eLogError, "Torrents: Empty file ", path);
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}
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else
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LogPrint (eLogError, "Torrents: Can't open file ", path);
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}
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void TorrentsTunnel::Accept ()
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{
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auto localDestination = GetLocalDestination ();
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if (localDestination)
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{
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if (!localDestination->IsAcceptingStreams ()) // set it as default if not set yet
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localDestination->AcceptStreams ([this](std::shared_ptr<i2p::stream::Stream> stream)
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{
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if (stream)
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{
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auto conn = std::make_shared<PeerConnection> (this, stream);
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AddHandler (conn);
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conn->ReceiveHandshake ();
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}
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});
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}
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else
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LogPrint (eLogError, "Torrents: Local destination not set");
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}
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void TorrentsTunnel::RequestTracker (std::shared_ptr<Torrent> torrent)
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{
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if (!torrent) return;
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i2p::http::HTTPReq req = torrent->GetTrackerRequest ();
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i2p::http::URL reqURL;
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reqURL.parse (req.uri);
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#if __cplusplus >= 202002L // C++20
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if (!reqURL.host.ends_with (".i2p"))
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#else
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if (reqURL.host.find(".i2p") == reqURL.host.npos)
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#endif
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{
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LogPrint (eLogWarning, "Torrents: Non-I2P address ", reqURL.host, " for torrent ", torrent->GetName ());
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return;
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}
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req.AddHeader ("peer_id", m_PeerID);
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req.AddHeader ("ip", GetLocalDestination ()->GetIdentHash ().ToBase32 () + ".b32.i2p");
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req.AddHeader ("port", std::to_string (6881));
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req.AddHeader ("uploaded", "0"); // TODO
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req.AddHeader ("downloaded", "0"); // TODO
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req.AddHeader ("left", "1"); // TODO
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req.AddHeader ("compact", "1"); // TODO
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req.AddHeader ("numwant", "0"); // TODO
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CreateStream ([this, req, torrent](std::shared_ptr<i2p::stream::Stream> stream)
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{
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if (stream)
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{
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auto reqStr = req.to_string ();
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stream->Send ((const uint8_t *)reqStr.data (), reqStr.length ());
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ReceiveFromTracker (stream, torrent, std::make_shared<TrackerResponseBuffer>(), 0);
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}
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}, reqURL.host, reqURL.port);
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}
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void TorrentsTunnel::ReceiveFromTracker (std::shared_ptr<i2p::stream::Stream> stream,
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std::shared_ptr<Torrent> torrent, std::shared_ptr<TrackerResponseBuffer> buf, size_t offset)
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{
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if (!stream || !buf) return;
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if (stream->GetStatus () == i2p::stream::eStreamStatusNew ||
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stream->GetStatus () == i2p::stream::eStreamStatusOpen) // regular
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{
|
|
stream->AsyncReceive (boost::asio::buffer (buf->data() + offset, TRACKER_RESPONSE_BUFFER_SIZE - offset),
|
|
[this, stream, torrent, buf, offset](const boost::system::error_code& ecode, size_t bytes_transferred)
|
|
{
|
|
if (ecode)
|
|
{
|
|
if (ecode != boost::asio::error::operation_aborted && bytes_transferred > 0)
|
|
HandleTrackerResponse (torrent, buf, offset + bytes_transferred);
|
|
stream->Close ();
|
|
}
|
|
else
|
|
{
|
|
size_t offset1 = offset + bytes_transferred;
|
|
if (stream->IsOpen () && offset1 < TRACKER_RESPONSE_BUFFER_SIZE)
|
|
ReceiveFromTracker (stream, torrent, buf, offset1);
|
|
else
|
|
HandleTrackerResponse (torrent, buf, offset1);
|
|
}
|
|
}, TRACKER_RESPONSE_TIMEOUT);
|
|
}
|
|
else // closed by peer
|
|
{
|
|
// get remaining data
|
|
auto len = stream->ReadSome (buf->data() + offset, TRACKER_RESPONSE_BUFFER_SIZE - offset);
|
|
if (len > 0) // still some data
|
|
{
|
|
offset += len;
|
|
HandleTrackerResponse (torrent, buf, offset);
|
|
}
|
|
else // no more data
|
|
stream->Close ();
|
|
}
|
|
}
|
|
|
|
void TorrentsTunnel::HandleTrackerResponse (std::shared_ptr<Torrent> torrent,
|
|
std::shared_ptr<TrackerResponseBuffer> buf, size_t len)
|
|
{
|
|
if (!len || !torrent) return;
|
|
std::string_view response ((const char *)buf->data (), len);
|
|
i2p::http::HTTPRes res;
|
|
int headersLen = res.parse (response);
|
|
if (headersLen <= 0)
|
|
{
|
|
LogPrint (eLogWarning, "Torrents: Can't parse tracker response");
|
|
return;
|
|
}
|
|
if (res.code != 200)
|
|
{
|
|
LogPrint (eLogWarning, "Torrents: Tracker response code ", res.code);
|
|
return;
|
|
}
|
|
int contentLen = res.content_length();
|
|
if (headersLen + contentLen > (int)len)
|
|
{
|
|
LogPrint (eLogWarning, "Torrents: Tracker response incomplete");
|
|
return;
|
|
}
|
|
torrent->ParseTrackerResponse (response.substr (headersLen, contentLen));
|
|
}
|
|
}
|
|
}
|