transmission/libtransmission/magnet-metainfo.cc

204 lines
5.5 KiB
C++

// This file Copyright © 2010-2022 Mnemosyne LLC.
// It may be used under GPLv2 (SPDX: GPL-2.0), GPLv3 (SPDX: GPL-3.0),
// or any future license endorsed by Mnemosyne LLC.
// License text can be found in the licenses/ folder.
#include <array>
#include <cstring>
#include <string>
#include <string_view>
#include "transmission.h"
#include "crypto-utils.h"
#include "error.h"
#include "error-types.h"
#include "magnet-metainfo.h"
#include "tr-assert.h"
#include "utils.h"
#include "variant.h"
#include "web-utils.h"
using namespace std::literals;
/* this base32 code converted from code by Robert Kaye and Gordon Mohr
* and is public domain. see http://bitzi.com/publicdomain for more info */
namespace
{
namespace bitzi
{
auto constexpr Base32Lookup = std::array<int, 80>{
0xFF, 0xFF, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, /* '0', '1', '2', '3', '4', '5', '6', '7' */
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, /* '8', '9', ':', ';', '<', '=', '>', '?' */
0xFF, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, /* '@', 'A', 'B', 'C', 'D', 'E', 'F', 'G' */
0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, /* 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O' */
0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, /* 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W' */
0x17, 0x18, 0x19, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, /* 'X', 'Y', 'Z', '[', '\', ']', '^', '_' */
0xFF, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, /* '`', 'a', 'b', 'c', 'd', 'e', 'f', 'g' */
0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, /* 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o' */
0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, /* 'p', 'q', 'r', 's', 't', 'u', 'v', 'w' */
0x17, 0x18, 0x19, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF /* 'x', 'y', 'z', '{', '|', '}', '~', 'DEL' */
};
void base32_to_sha1(uint8_t* out, char const* in, size_t const inlen)
{
TR_ASSERT(inlen == 32);
size_t const outlen = 20;
memset(out, 0, 20);
size_t index = 0;
size_t offset = 0;
for (size_t i = 0; i < inlen; ++i)
{
int lookup = in[i] - '0';
/* Skip chars outside the lookup table */
if (lookup < 0)
{
continue;
}
/* If this digit is not in the table, ignore it */
int const digit = Base32Lookup[lookup];
if (digit == 0xFF)
{
continue;
}
if (index <= 3)
{
index = (index + 5) % 8;
if (index == 0)
{
out[offset] |= digit;
offset++;
if (offset >= outlen)
{
break;
}
}
else
{
out[offset] |= digit << (8 - index);
}
}
else
{
index = (index + 5) % 8;
out[offset] |= digit >> index;
offset++;
if (offset >= outlen)
{
break;
}
out[offset] |= digit << (8 - index);
}
}
}
} // namespace bitzi
} // namespace
/***
****
***/
std::string tr_magnet_metainfo::magnet() const
{
auto s = std::string{};
s += "magnet:?xt=urn:btih:"sv;
s += infoHashString();
if (!std::empty(name_))
{
s += "&dn="sv;
tr_http_escape(s, name_, true);
}
for (auto const& tracker : this->announceList())
{
s += "&tr="sv;
tr_http_escape(s, tracker.announce.full, true);
}
for (auto const& webseed : webseed_urls_)
{
s += "&ws="sv;
tr_http_escape(s, webseed, true);
}
return s;
}
bool tr_magnet_metainfo::parseMagnet(std::string_view magnet_link, tr_error** error)
{
auto const parsed = tr_urlParse(magnet_link);
if (!parsed || parsed->scheme != "magnet"sv)
{
tr_error_set(error, TR_ERROR_EINVAL, "Error parsing URL"sv);
return false;
}
bool got_checksum = false;
for (auto const& [key, value] : tr_url_query_view{ parsed->query })
{
if (key == "dn"sv)
{
this->setName(tr_urlPercentDecode(value));
}
else if (key == "tr"sv || tr_strvStartsWith(key, "tr."sv))
{
// "tr." explanation @ https://trac.transmissionbt.com/ticket/3341
this->announce_list_.add(this->announce_list_.nextTier(), tr_urlPercentDecode(value));
}
else if (key == "ws"sv)
{
auto const url = tr_urlPercentDecode(value);
auto const url_sv = tr_strvStrip(url);
if (tr_urlIsValid(url_sv))
{
this->webseed_urls_.emplace_back(url_sv);
}
}
else if (key == "xt"sv)
{
auto constexpr ValPrefix = "urn:btih:"sv;
if (tr_strvStartsWith(value, ValPrefix))
{
auto const hash = value.substr(std::size(ValPrefix));
switch (std::size(hash))
{
case TR_SHA1_DIGEST_STRLEN:
this->info_hash_ = tr_sha1_from_string(hash);
got_checksum = true;
break;
case 32:
bitzi::base32_to_sha1(
reinterpret_cast<uint8_t*>(std::data(this->info_hash_)),
std::data(hash),
std::size(hash));
got_checksum = true;
break;
default:
break;
}
}
}
}
info_hash_str_ = tr_sha1_to_string(this->infoHash());
return got_checksum;
}