1
0
Fork 0
mirror of https://github.com/transmission/transmission synced 2024-12-27 18:18:10 +00:00
transmission/libtransmission/magnet-metainfo.cc
Charles Kerr 1ba81938bf
refactor: use std::string_view in benc parser (#2182)
* refactor: use std::string_view to parse benc

* refactor: simplify private parsing API in variant.cc

* chore: remove unneeded includes

* refactor: merge tr_variantFromBenc and tr_variantFromBencFull
2021-11-16 21:29:30 -06:00

297 lines
8 KiB
C++

/*
* This file Copyright (C) 2010-2014 Mnemosyne LLC
*
* It may be used under the GNU GPL versions 2 or 3
* or any future license endorsed by Mnemosyne LLC.
*
*/
#include <cstring>
#include <string>
#include <string_view>
#include "transmission.h"
#include "crypto-utils.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 bitzi
{
int constexpr base32Lookup[] = {
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
/***
****
***/
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& it : trackers)
{
s += "&tr="sv;
tr_http_escape(s, tr_quark_get_string_view(it.second.announce_url), true);
}
for (auto const& webseed : webseed_urls)
{
s += "&ws="sv;
tr_http_escape(s, webseed, true);
}
return s;
}
static tr_quark announceToScrape(std::string_view announce)
{
auto buf = std::string{};
if (!tr_magnet_metainfo::convertAnnounceToScrape(buf, announce))
{
return TR_KEY_NONE;
}
return tr_quark_new(buf);
}
bool tr_magnet_metainfo::addTracker(tr_tracker_tier_t tier, std::string_view announce_sv)
{
announce_sv = tr_strvStrip(announce_sv);
if (!tr_urlIsValidTracker(announce_sv))
{
return false;
}
auto const announce_url = tr_quark_new(announce_sv);
auto const scrape_url = announceToScrape(announce_sv);
this->trackers.insert({ tier, { announce_url, scrape_url, tier } });
return true;
}
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");
return false;
}
bool got_checksum = false;
auto tier = tr_tracker_tier_t{ 0 };
for (auto const& [key, value] : tr_url_query_view{ parsed->query })
{
if (key == "dn"sv)
{
this->name = tr_urlPercentDecode(value);
}
else if (key == "tr"sv || tr_strvStartsWith(key, "tr."sv))
{
// "tr." explanation @ https://trac.transmissionbt.com/ticket/3341
addTracker(tier++, 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 40:
tr_hex_to_sha1(std::data(this->info_hash), std::data(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;
}
}
}
}
return got_checksum;
}
bool tr_magnet_metainfo::convertAnnounceToScrape(std::string& out, std::string_view in)
{
// To derive the scrape URL use the following steps:
// Begin with the announce URL. Find the last '/' in it.
// If the text immediately following that '/' isn't 'announce'
// it will be taken as a sign that that tracker doesn't support
// the scrape convention. If it does, substitute 'scrape' for
// 'announce' to find the scrape page.
auto constexpr oldval = "/announce"sv;
auto pos = in.rfind(oldval.front());
if (pos != in.npos && in.find(oldval, pos) == pos)
{
auto const prefix = in.substr(0, pos);
auto const suffix = in.substr(pos + std::size(oldval));
tr_buildBuf(out, prefix, "/scrape"sv, suffix);
return true;
}
// some torrents with UDP announce URLs don't have /announce
if (tr_strvStartsWith(in, "udp:"sv))
{
out = in;
return true;
}
return false;
}
void tr_magnet_metainfo::toVariant(tr_variant* top) const
{
tr_variantInitDict(top, 4);
// announce list
auto n = std::size(this->trackers);
if (n == 1)
{
tr_variantDictAddStr(top, TR_KEY_announce, tr_quark_get_string_view(std::begin(this->trackers)->second.announce_url));
}
else
{
auto* list = tr_variantDictAddList(top, TR_KEY_announce_list, n);
for (auto const& pair : this->trackers)
{
tr_variantListAddStr(tr_variantListAddList(list, 1), tr_quark_get_string_view(pair.second.announce_url));
}
}
// webseeds
n = std::size(this->webseed_urls);
if (n != 0)
{
tr_variant* list = tr_variantDictAddList(top, TR_KEY_url_list, n);
for (auto& url : this->webseed_urls)
{
tr_variantListAddStr(list, url);
}
}
// nonstandard keys
auto* const d = tr_variantDictAddDict(top, TR_KEY_magnet_info, 2);
tr_variantDictAddRaw(d, TR_KEY_info_hash, std::data(this->info_hash), std::size(this->info_hash));
if (!std::empty(this->name))
{
tr_variantDictAddStr(d, TR_KEY_display_name, this->name);
}
}