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transmission/libtransmission/blocklist.cc

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// This file Copyright © 2008-2022 Mnemosyne LLC.
// It may be used under GPLv2 (SPDX: GPL-2.0-only), GPLv3 (SPDX: GPL-3.0-only),
// or any future license endorsed by Mnemosyne LLC.
// License text can be found in the licenses/ folder.
#include <cerrno>
#include <cstdio>
#include <cstdlib> /* bsearch(), qsort() */
#include <cstring>
#include <string_view>
#include <fmt/core.h>
#include "transmission.h"
#include "blocklist.h"
#include "error.h"
#include "file.h"
#include "log.h"
#include "net.h"
#include "tr-assert.h"
#include "utils.h"
/***
**** PRIVATE
***/
struct tr_ipv4_range
{
uint32_t begin;
uint32_t end;
};
struct tr_blocklistFile
{
bool isEnabled;
tr_sys_file_t fd;
size_t ruleCount;
uint64_t byteCount;
char* filename;
struct tr_ipv4_range* rules;
};
static void blocklistClose(tr_blocklistFile* b)
{
if (b->rules != nullptr)
{
tr_sys_file_unmap(b->rules, b->byteCount);
tr_sys_file_close(b->fd);
b->rules = nullptr;
b->ruleCount = 0;
b->byteCount = 0;
b->fd = TR_BAD_SYS_FILE;
}
}
static void blocklistLoad(tr_blocklistFile* b)
{
blocklistClose(b);
auto info = tr_sys_path_info{};
if (!tr_sys_path_get_info(b->filename, 0, &info))
{
return;
}
auto const byteCount = info.size;
if (byteCount == 0)
{
return;
}
tr_error* error = nullptr;
auto const fd = tr_sys_file_open(b->filename, TR_SYS_FILE_READ, 0, &error);
if (fd == TR_BAD_SYS_FILE)
{
tr_logAddWarn(fmt::format(
_("Couldn't read '{path}': {error} ({error_code})"),
fmt::arg("path", b->filename),
fmt::arg("error", error->message),
fmt::arg("error_code", error->code)));
tr_error_free(error);
return;
}
b->rules = static_cast<struct tr_ipv4_range*>(tr_sys_file_map_for_reading(fd, 0, byteCount, &error));
if (b->rules == nullptr)
{
tr_logAddWarn(fmt::format(
_("Couldn't read '{path}': {error} ({error_code})"),
fmt::arg("path", b->filename),
fmt::arg("error", error->message),
fmt::arg("error_code", error->code)));
tr_sys_file_close(fd);
tr_error_free(error);
return;
}
b->fd = fd;
b->byteCount = byteCount;
b->ruleCount = byteCount / sizeof(struct tr_ipv4_range);
tr_logAddInfo(fmt::format(
ngettext("Blocklist '{path}' has {count} entry", "Blocklist '{path}' has {count} entries", b->ruleCount),
fmt::arg("path", tr_sys_path_basename(b->filename)),
fmt::arg("count", b->ruleCount)));
}
static void blocklistEnsureLoaded(tr_blocklistFile* b)
{
if (b->rules == nullptr)
{
blocklistLoad(b);
}
}
static int compareAddressToRange(void const* va, void const* vb)
{
auto const* a = static_cast<uint32_t const*>(va);
auto const* b = static_cast<struct tr_ipv4_range const*>(vb);
if (*a < b->begin)
{
return -1;
}
if (*a > b->end)
{
return 1;
}
return 0;
}
static void blocklistDelete(tr_blocklistFile* b)
{
blocklistClose(b);
tr_sys_path_remove(b->filename);
}
/***
**** PACKAGE-VISIBLE
***/
tr_blocklistFile* tr_blocklistFileNew(char const* filename, bool isEnabled)
{
auto* const b = tr_new0(tr_blocklistFile, 1);
b->fd = TR_BAD_SYS_FILE;
b->filename = tr_strdup(filename);
b->isEnabled = isEnabled;
return b;
}
char const* tr_blocklistFileGetFilename(tr_blocklistFile const* b)
{
return b->filename;
}
void tr_blocklistFileFree(tr_blocklistFile* b)
{
blocklistClose(b);
tr_free(b->filename);
tr_free(b);
}
int tr_blocklistFileGetRuleCount(tr_blocklistFile const* b)
{
blocklistEnsureLoaded((tr_blocklistFile*)b);
return b->ruleCount;
}
void tr_blocklistFileSetEnabled(tr_blocklistFile* b, bool isEnabled)
{
TR_ASSERT(b != nullptr);
b->isEnabled = isEnabled;
}
bool tr_blocklistFileHasAddress(tr_blocklistFile* b, tr_address const* addr)
{
TR_ASSERT(tr_address_is_valid(addr));
if (!b->isEnabled || addr->type == TR_AF_INET6)
{
return false;
}
blocklistEnsureLoaded(b);
if (b->rules == nullptr || b->ruleCount == 0)
{
return false;
}
auto const needle = ntohl(addr->addr.addr4.s_addr);
auto const* range = static_cast<struct tr_ipv4_range const*>(
bsearch(&needle, b->rules, b->ruleCount, sizeof(struct tr_ipv4_range), compareAddressToRange));
return range != nullptr;
}
/*
* P2P plaintext format: "comment:x.x.x.x-y.y.y.y"
* http://wiki.phoenixlabs.org/wiki/P2P_Format
* https://en.wikipedia.org/wiki/PeerGuardian#P2P_plaintext_format
*/
static bool parseLine1(std::string_view line, struct tr_ipv4_range* range)
{
// remove leading "comment:"
auto pos = line.find(':');
if (pos == std::string_view::npos)
{
return false;
}
line = line.substr(pos + 1);
// parse the leading 'x.x.x.x'
pos = line.find('-');
if (pos == std::string_view::npos)
{
return false;
}
if (auto addr = tr_address{}; tr_address_from_string(&addr, line.substr(0, pos)))
{
range->begin = ntohl(addr.addr.addr4.s_addr);
}
else
{
return false;
}
line = line.substr(pos + 1);
// parse the trailing 'y.y.y.y'
if (auto addr = tr_address{}; tr_address_from_string(&addr, line))
{
range->end = ntohl(addr.addr.addr4.s_addr);
}
else
{
return false;
}
return true;
}
/*
* DAT / eMule format: "000.000.000.000 - 000.255.255.255 , 000 , invalid ip"a
* https://sourceforge.net/p/peerguardian/wiki/dev-blocklist-format-dat/
*/
static bool parseLine2(std::string_view line, struct tr_ipv4_range* range)
{
static auto constexpr Delim1 = std::string_view{ " - " };
static auto constexpr Delim2 = std::string_view{ " , " };
auto pos = line.find(Delim1);
if (pos == std::string_view::npos)
{
return false;
}
if (auto addr = tr_address{}; tr_address_from_string(&addr, line.substr(0, pos)))
{
range->begin = ntohl(addr.addr.addr4.s_addr);
}
else
{
return false;
}
line = line.substr(pos + std::size(Delim1));
pos = line.find(Delim2);
if (pos == std::string_view::npos)
{
return false;
}
if (auto addr = tr_address{}; tr_address_from_string(&addr, line.substr(0, pos)))
{
range->end = ntohl(addr.addr.addr4.s_addr);
}
else
{
return false;
}
return true;
}
/*
* CIDR notation: "0.0.0.0/8", IPv4 only
* https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing#CIDR_notation
*/
static bool parseLine3(char const* line, struct tr_ipv4_range* range)
{
unsigned int ip[4];
unsigned int pflen = 0;
uint32_t ip_u = 0;
uint32_t mask = 0xffffffff;
if (sscanf(line, "%u.%u.%u.%u/%u", TR_ARG_TUPLE(&ip[0], &ip[1], &ip[2], &ip[3]), &pflen) != 5)
{
return false;
}
if (pflen > 32 || ip[0] > 0xff || ip[1] > 0xff || ip[2] > 0xff || ip[3] > 0xff)
{
return false;
}
/* this is host order */
mask <<= 32 - pflen;
ip_u = ip[0] << 24 | ip[1] << 16 | ip[2] << 8 | ip[3];
/* fill the non-prefix bits the way we need it */
range->begin = ip_u & mask;
range->end = ip_u | (~mask);
return true;
}
static bool parseLine(char const* line, struct tr_ipv4_range* range)
{
return parseLine1(line, range) || parseLine2(line, range) || parseLine3(line, range);
}
static int compareAddressRangesByFirstAddress(void const* va, void const* vb)
{
auto const* a = static_cast<struct tr_ipv4_range const*>(va);
auto const* b = static_cast<struct tr_ipv4_range const*>(vb);
if (a->begin < b->begin)
{
return -1;
}
if (a->begin > b->begin)
{
return 1;
}
return 0;
}
int tr_blocklistFileSetContent(tr_blocklistFile* b, char const* filename)
{
int inCount = 0;
char line[2048];
// TODO: should be a vector
struct tr_ipv4_range* ranges = nullptr;
size_t ranges_alloc = 0;
size_t ranges_count = 0;
tr_error* error = nullptr;
if (filename == nullptr)
{
blocklistDelete(b);
return 0;
}
auto const in = tr_sys_file_open(filename, TR_SYS_FILE_READ, 0, &error);
if (in == TR_BAD_SYS_FILE)
{
tr_logAddWarn(fmt::format(
_("Couldn't read '{path}': {error} ({error_code})"),
fmt::arg("path", filename),
fmt::arg("error", error->message),
fmt::arg("error_code", error->code)));
tr_error_free(error);
return 0;
}
blocklistClose(b);
auto const out = tr_sys_file_open(b->filename, TR_SYS_FILE_WRITE | TR_SYS_FILE_CREATE | TR_SYS_FILE_TRUNCATE, 0666, &error);
if (out == TR_BAD_SYS_FILE)
{
tr_logAddWarn(fmt::format(
_("Couldn't read '{path}': {error} ({error_code})"),
fmt::arg("path", b->filename),
fmt::arg("error", error->message),
fmt::arg("error_code", error->code)));
tr_error_free(error);
tr_sys_file_close(in);
return 0;
}
/* load the rules into memory */
while (tr_sys_file_read_line(in, line, sizeof(line)))
{
struct tr_ipv4_range range;
++inCount;
if (!parseLine(line, &range))
{
/* don't try to display the actual lines - it causes issues */
tr_logAddWarn(fmt::format(_("Couldn't parse line: '{line}'"), fmt::arg("line", inCount)));
continue;
}
if (ranges_alloc == ranges_count)
{
ranges_alloc += 4096; /* arbitrary */
ranges = tr_renew(struct tr_ipv4_range, ranges, ranges_alloc);
}
ranges[ranges_count++] = range;
}
if (ranges_count > 0) /* sort and merge */
{
struct tr_ipv4_range* keep = ranges;
/* sort */
qsort(ranges, ranges_count, sizeof(struct tr_ipv4_range), compareAddressRangesByFirstAddress);
/* merge */
for (size_t i = 1; i < ranges_count; ++i)
{
struct tr_ipv4_range const* r = &ranges[i];
if (keep->end < r->begin)
{
*++keep = *r;
}
else if (keep->end < r->end)
{
keep->end = r->end;
}
}
ranges_count = keep + 1 - ranges;
#ifdef TR_ENABLE_ASSERTS
/* sanity checks: make sure the rules are sorted in ascending order and don't overlap */
for (size_t i = 0; i < ranges_count; ++i)
{
TR_ASSERT(ranges[i].begin <= ranges[i].end);
}
for (size_t i = 1; i < ranges_count; ++i)
{
TR_ASSERT(ranges[i - 1].end < ranges[i].begin);
}
#endif
}
if (!tr_sys_file_write(out, ranges, sizeof(struct tr_ipv4_range) * ranges_count, nullptr, &error))
{
tr_logAddWarn(fmt::format(
_("Couldn't save '{path}': {error} ({error_code})"),
fmt::arg("path", b->filename),
fmt::arg("error", error->message),
fmt::arg("error_code", error->code)));
tr_error_free(error);
}
else
{
tr_logAddInfo(fmt::format(
ngettext("Blocklist '{path}' has {count} entry", "Blocklist '{path}' has {count} entries", b->ruleCount),
fmt::arg("path", tr_sys_path_basename(b->filename)),
fmt::arg("count", b->ruleCount)));
}
tr_free(ranges);
tr_sys_file_close(out);
tr_sys_file_close(in);
blocklistLoad(b);
return ranges_count;
}
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