transmission/libtransmission/net.cc

766 lines
21 KiB
C++
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

// This file Copyright © 2010-2023 Transmission authors and contributors.
// It may be used under the MIT (SPDX: MIT) license.
// License text can be found in the licenses/ folder.
#include <algorithm>
#include <array>
#include <cerrno>
#include <climits>
#include <cstdint>
#include <cstring>
#include <iterator> // std::back_inserter
#include <string_view>
#include <utility> // std::pair
#include <sys/types.h>
#ifdef _WIN32
#include <ws2tcpip.h>
#else
#include <netinet/tcp.h> /* TCP_CONGESTION */
#endif
#include <event2/util.h>
#include <fmt/core.h>
#include "libtransmission/transmission.h"
#include "libtransmission/log.h"
#include "libtransmission/net.h"
#include "libtransmission/peer-socket.h"
#include "libtransmission/session.h"
#include "libtransmission/tr-assert.h"
#include "libtransmission/tr-macros.h"
#include "libtransmission/tr-utp.h"
#include "libtransmission/utils.h"
using namespace std::literals;
#ifndef IN_MULTICAST
#define IN_MULTICAST(a) (((a)&0xf0000000) == 0xe0000000)
#endif
std::string tr_net_strerror(int err)
{
#ifdef _WIN32
auto buf = std::array<char, 512>{};
(void)FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM, nullptr, err, 0, std::data(buf), std::size(buf), nullptr);
return std::string{ tr_strv_strip(std::data(buf)) };
#else
return std::string{ tr_strerror(err) };
#endif
}
std::string_view tr_ip_protocol_to_sv(tr_address_type type)
{
using namespace std::literals;
switch (type)
{
case TR_AF_INET:
return "IPv4"sv;
case TR_AF_INET6:
return "IPv6"sv;
default:
TR_ASSERT_MSG(false, "invalid address family");
return {};
}
}
int tr_ip_protocol_to_af(tr_address_type type)
{
switch (type)
{
case TR_AF_INET:
return AF_INET;
case TR_AF_INET6:
return AF_INET6;
default:
TR_ASSERT_MSG(false, "invalid address family");
return {};
}
}
tr_address_type tr_af_to_ip_protocol(int af)
{
switch (af)
{
case AF_INET:
return TR_AF_INET;
case AF_INET6:
return TR_AF_INET6;
default:
TR_ASSERT_MSG(false, "invalid address family");
return NUM_TR_AF_INET_TYPES;
}
}
// - TCP Sockets
[[nodiscard]] std::optional<tr_tos_t> tr_tos_t::from_string(std::string_view name)
{
auto const needle = tr_strlower(tr_strv_strip(name));
for (auto const& [value, key] : Names)
{
if (needle == key)
{
return tr_tos_t(value);
}
}
if (auto value = tr_num_parse<int>(needle); value)
{
return tr_tos_t(*value);
}
return {};
}
std::string tr_tos_t::toString() const
{
for (auto const& [value, key] : Names)
{
if (value_ == value)
{
return std::string{ key };
}
}
return std::to_string(value_);
}
void tr_netSetTOS([[maybe_unused]] tr_socket_t s, [[maybe_unused]] int tos, tr_address_type type)
{
if (s == TR_BAD_SOCKET)
{
return;
}
if (type == TR_AF_INET)
{
#if defined(IP_TOS) && !defined(_WIN32)
if (setsockopt(s, IPPROTO_IP, IP_TOS, (void const*)&tos, sizeof(tos)) == -1)
{
tr_logAddDebug(fmt::format("Can't set TOS '{}': {}", tos, tr_net_strerror(sockerrno)));
}
#endif
}
else if (type == TR_AF_INET6)
{
#if defined(IPV6_TCLASS) && !defined(_WIN32)
if (setsockopt(s, IPPROTO_IPV6, IPV6_TCLASS, (void const*)&tos, sizeof(tos)) == -1)
{
tr_logAddDebug(fmt::format("Can't set IPv6 QoS '{}': {}", tos, tr_net_strerror(sockerrno)));
}
#endif
}
else
{
/* program should never reach here! */
tr_logAddDebug("Something goes wrong while setting TOS/Traffic-Class");
}
}
void tr_netSetCongestionControl([[maybe_unused]] tr_socket_t s, [[maybe_unused]] char const* algorithm)
{
#ifdef TCP_CONGESTION
if (setsockopt(s, IPPROTO_TCP, TCP_CONGESTION, (void const*)algorithm, strlen(algorithm) + 1) == -1)
{
tr_logAddDebug(fmt::format("Can't set congestion control algorithm '{}': {}", algorithm, tr_net_strerror(sockerrno)));
}
#endif
}
static tr_socket_t createSocket(int domain, int type)
{
auto const sockfd = socket(domain, type, 0);
if (sockfd == TR_BAD_SOCKET)
{
if (sockerrno != EAFNOSUPPORT)
{
tr_logAddWarn(fmt::format(
_("Couldn't create socket: {error} ({error_code})"),
fmt::arg("error", tr_net_strerror(sockerrno)),
fmt::arg("error_code", sockerrno)));
}
return TR_BAD_SOCKET;
}
if (evutil_make_socket_nonblocking(sockfd) == -1)
{
tr_net_close_socket(sockfd);
return TR_BAD_SOCKET;
}
if (static bool buf_logged = false; !buf_logged)
{
int i = 0;
socklen_t size = sizeof(i);
if (getsockopt(sockfd, SOL_SOCKET, SO_SNDBUF, reinterpret_cast<char*>(&i), &size) != -1)
{
tr_logAddTrace(fmt::format("SO_SNDBUF size is {}", i));
}
i = 0;
size = sizeof(i);
if (getsockopt(sockfd, SOL_SOCKET, SO_RCVBUF, reinterpret_cast<char*>(&i), &size) != -1)
{
tr_logAddTrace(fmt::format("SO_RCVBUF size is {}", i));
}
buf_logged = true;
}
return sockfd;
}
tr_peer_socket tr_netOpenPeerSocket(tr_session* session, tr_socket_address const& socket_address, bool client_is_seed)
{
auto const& [addr, port] = socket_address;
TR_ASSERT(addr.is_valid());
TR_ASSERT(!tr_peer_socket::limit_reached(session));
if (tr_peer_socket::limit_reached(session) || !session->allowsTCP() || !socket_address.is_valid_for_peers())
{
return {};
}
auto const s = createSocket(tr_ip_protocol_to_af(addr.type), SOCK_STREAM);
if (s == TR_BAD_SOCKET)
{
return {};
}
// seeds don't need a big read buffer, so make it smaller
if (client_is_seed)
{
int n = 8192;
if (setsockopt(s, SOL_SOCKET, SO_RCVBUF, reinterpret_cast<char const*>(&n), sizeof(n)) == -1)
{
tr_logAddDebug(fmt::format("Unable to set SO_RCVBUF on socket {}: {}", s, tr_net_strerror(sockerrno)));
}
}
auto const [sock, addrlen] = socket_address.to_sockaddr();
// set source address
auto const source_addr = session->bind_address(addr.type);
auto const [source_sock, sourcelen] = tr_socket_address::to_sockaddr(source_addr, {});
if (bind(s, reinterpret_cast<sockaddr const*>(&source_sock), sourcelen) == -1)
{
tr_logAddWarn(fmt::format(
_("Couldn't set source address {address} on {socket}: {error} ({error_code})"),
fmt::arg("address", source_addr.display_name()),
fmt::arg("socket", s),
fmt::arg("error", tr_net_strerror(sockerrno)),
fmt::arg("error_code", sockerrno)));
tr_net_close_socket(s);
return {};
}
auto ret = tr_peer_socket{};
if (connect(s, reinterpret_cast<sockaddr const*>(&sock), addrlen) == -1 &&
#ifdef _WIN32
sockerrno != WSAEWOULDBLOCK &&
#endif
sockerrno != EINPROGRESS)
{
if (auto const tmperrno = sockerrno;
(tmperrno != ECONNREFUSED && tmperrno != ENETUNREACH && tmperrno != EHOSTUNREACH) || addr.is_ipv4())
{
tr_logAddWarn(fmt::format(
_("Couldn't connect socket {socket} to {address}:{port}: {error} ({error_code})"),
fmt::arg("socket", s),
fmt::arg("address", addr.display_name()),
fmt::arg("port", port.host()),
fmt::arg("error", tr_net_strerror(tmperrno)),
fmt::arg("error_code", tmperrno)));
}
tr_net_close_socket(s);
}
else
{
ret = tr_peer_socket{ session, socket_address, s };
}
tr_logAddTrace(fmt::format("New OUTGOING connection {} ({})", s, socket_address.display_name()));
return ret;
}
static tr_socket_t tr_netBindTCPImpl(tr_address const& addr, tr_port port, bool suppress_msgs, int* err_out)
{
TR_ASSERT(addr.is_valid());
auto const fd = socket(tr_ip_protocol_to_af(addr.type), SOCK_STREAM, 0);
if (fd == TR_BAD_SOCKET)
{
*err_out = sockerrno;
return TR_BAD_SOCKET;
}
if (evutil_make_socket_nonblocking(fd) == -1)
{
*err_out = sockerrno;
tr_net_close_socket(fd);
return TR_BAD_SOCKET;
}
int optval = 1;
(void)setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, reinterpret_cast<char const*>(&optval), sizeof(optval));
(void)setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, reinterpret_cast<char const*>(&optval), sizeof(optval));
#ifdef IPV6_V6ONLY
if (addr.is_ipv6() &&
(setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, reinterpret_cast<char const*>(&optval), sizeof(optval)) == -1) &&
(sockerrno != ENOPROTOOPT)) // if the kernel doesn't support it, ignore it
{
*err_out = sockerrno;
tr_net_close_socket(fd);
return TR_BAD_SOCKET;
}
#endif
auto const [sock, addrlen] = tr_socket_address::to_sockaddr(addr, port);
if (bind(fd, reinterpret_cast<sockaddr const*>(&sock), addrlen) == -1)
{
int const err = sockerrno;
if (!suppress_msgs)
{
tr_logAddError(fmt::format(
err == EADDRINUSE ?
_("Couldn't bind port {port} on {address}: {error} ({error_code}) -- Is another copy of Transmission already running?") :
_("Couldn't bind port {port} on {address}: {error} ({error_code})"),
fmt::arg("address", addr.display_name()),
fmt::arg("port", port.host()),
fmt::arg("error", tr_net_strerror(err)),
fmt::arg("error_code", err)));
}
tr_net_close_socket(fd);
*err_out = err;
return TR_BAD_SOCKET;
}
if (!suppress_msgs)
{
tr_logAddDebug(fmt::format(FMT_STRING("Bound socket {:d} to port {:d} on {:s}"), fd, port.host(), addr.display_name()));
}
#ifdef TCP_FASTOPEN
#ifndef SOL_TCP
#define SOL_TCP IPPROTO_TCP
#endif
optval = 5;
(void)setsockopt(fd, SOL_TCP, TCP_FASTOPEN, reinterpret_cast<char const*>(&optval), sizeof(optval));
#endif
#ifdef _WIN32
if (listen(fd, SOMAXCONN) == -1)
#else /* _WIN32 */
/* Listen queue backlog will be capped to the operating system's limit. */
if (listen(fd, INT_MAX) == -1)
#endif /* _WIN32 */
{
*err_out = sockerrno;
tr_net_close_socket(fd);
return TR_BAD_SOCKET;
}
return fd;
}
tr_socket_t tr_netBindTCP(tr_address const& addr, tr_port port, bool suppress_msgs)
{
int unused = 0;
return tr_netBindTCPImpl(addr, port, suppress_msgs, &unused);
}
std::optional<std::pair<tr_socket_address, tr_socket_t>> tr_netAccept(tr_session* session, tr_socket_t listening_sockfd)
{
TR_ASSERT(session != nullptr);
// accept the incoming connection
auto sock = sockaddr_storage{};
socklen_t len = sizeof(struct sockaddr_storage);
auto const sockfd = accept(listening_sockfd, reinterpret_cast<sockaddr*>(&sock), &len);
if (sockfd == TR_BAD_SOCKET)
{
return {};
}
// get the address and port,
// make the socket unblocking,
// and confirm we don't have too many peers
auto const addrport = tr_socket_address::from_sockaddr(reinterpret_cast<struct sockaddr*>(&sock));
if (!addrport || evutil_make_socket_nonblocking(sockfd) == -1 || tr_peer_socket::limit_reached(session))
{
tr_net_close_socket(sockfd);
return {};
}
return std::pair{ *addrport, sockfd };
}
void tr_net_close_socket(tr_socket_t sockfd)
{
evutil_closesocket(sockfd);
}
// ---
namespace
{
namespace is_valid_for_peers_helpers
{
[[nodiscard]] constexpr auto is_ipv4_mapped_address(tr_address const& addr)
{
return addr.is_ipv6() && IN6_IS_ADDR_V4MAPPED(&addr.addr.addr6);
}
[[nodiscard]] constexpr auto is_ipv6_link_local_address(tr_address const& addr)
{
return addr.is_ipv6() && IN6_IS_ADDR_LINKLOCAL(&addr.addr.addr6);
}
/* isMartianAddr was written by Juliusz Chroboczek,
and is covered under the same license as third-party/dht/dht.c. */
[[nodiscard]] auto is_martian_addr(tr_address const& addr)
{
static auto constexpr Zeroes = std::array<unsigned char, 16>{};
switch (addr.type)
{
case TR_AF_INET:
{
auto const* const address = reinterpret_cast<unsigned char const*>(&addr.addr.addr4);
return address[0] == 0 || address[0] == 127 || (address[0] & 0xE0) == 0xE0;
}
case TR_AF_INET6:
{
auto const* const address = reinterpret_cast<unsigned char const*>(&addr.addr.addr6);
return address[0] == 0xFF ||
(memcmp(address, std::data(Zeroes), 15) == 0 && (address[15] == 0 || address[15] == 1));
}
default:
return true;
}
}
} // namespace is_valid_for_peers_helpers
} // namespace
// --- tr_port
std::pair<tr_port, std::byte const*> tr_port::from_compact(std::byte const* compact) noexcept
{
static auto constexpr PortLen = size_t{ 2 };
static_assert(PortLen == sizeof(uint16_t));
auto nport = uint16_t{};
std::copy_n(compact, PortLen, reinterpret_cast<std::byte*>(&nport));
compact += PortLen;
return std::make_pair(tr_port::from_network(nport), compact);
}
// --- tr_address
std::optional<tr_address> tr_address::from_string(std::string_view address_sv)
{
auto const address_sz = tr_strbuf<char, TR_ADDRSTRLEN>{ address_sv };
auto addr = tr_address{};
addr.addr.addr4 = {};
if (evutil_inet_pton(AF_INET, address_sz, &addr.addr.addr4) == 1)
{
addr.type = TR_AF_INET;
return addr;
}
addr.addr.addr6 = {};
if (evutil_inet_pton(AF_INET6, address_sz, &addr.addr.addr6) == 1)
{
addr.type = TR_AF_INET6;
return addr;
}
return {};
}
std::string_view tr_address::display_name(char* out, size_t outlen) const
{
TR_ASSERT(is_valid());
return evutil_inet_ntop(tr_ip_protocol_to_af(type), &addr, out, outlen);
}
[[nodiscard]] std::string tr_address::display_name() const
{
auto buf = std::array<char, INET6_ADDRSTRLEN>{};
return std::string{ display_name(std::data(buf), std::size(buf)) };
}
std::pair<tr_address, std::byte const*> tr_address::from_compact_ipv4(std::byte const* compact) noexcept
{
static auto constexpr Addr4Len = tr_address::CompactAddrBytes[TR_AF_INET];
auto address = tr_address{};
static_assert(sizeof(address.addr.addr4) == Addr4Len);
address.type = TR_AF_INET;
std::copy_n(compact, Addr4Len, reinterpret_cast<std::byte*>(&address.addr));
compact += Addr4Len;
return { address, compact };
}
std::pair<tr_address, std::byte const*> tr_address::from_compact_ipv6(std::byte const* compact) noexcept
{
static auto constexpr Addr6Len = tr_address::CompactAddrBytes[TR_AF_INET6];
auto address = tr_address{};
address.type = TR_AF_INET6;
std::copy_n(compact, Addr6Len, reinterpret_cast<std::byte*>(&address.addr.addr6.s6_addr));
compact += Addr6Len;
return { address, compact };
}
int tr_address::compare(tr_address const& that) const noexcept // <=>
{
// IPv6 addresses are always "greater than" IPv4
if (auto const val = tr_compare_3way(this->type, that.type); val != 0)
{
return val;
}
return this->is_ipv4() ? memcmp(&this->addr.addr4, &that.addr.addr4, sizeof(this->addr.addr4)) :
memcmp(&this->addr.addr6.s6_addr, &that.addr.addr6.s6_addr, sizeof(this->addr.addr6.s6_addr));
}
// https://en.wikipedia.org/wiki/Reserved_IP_addresses
[[nodiscard]] bool tr_address::is_global_unicast_address() const noexcept
{
if (is_ipv4())
{
auto const* const a = reinterpret_cast<uint8_t const*>(&addr.addr4.s_addr);
// [0.0.0.00.255.255.255]
// Current network.
if (a[0] == 0)
{
return false;
}
// [10.0.0.0 10.255.255.255]
// Used for local communications within a private network.
if (a[0] == 10)
{
return false;
}
// [100.64.0.0100.127.255.255]
// Shared address space for communications between a service provider
// and its subscribers when using a carrier-grade NAT.
if ((a[0] == 100) && (64 <= a[1] && a[1] <= 127))
{
return false;
}
// [169.254.0.0169.254.255.255]
// Used for link-local addresses[5] between two hosts on a single link
// when no IP address is otherwise specified, such as would have
// normally been retrieved from a DHCP server.
if (a[0] == 169 && a[1] == 254)
{
return false;
}
// [172.16.0.0172.31.255.255]
// Used for local communications within a private network.
if ((a[0] == 172) && (16 <= a[1] && a[1] <= 31))
{
return false;
}
// [192.0.0.0192.0.0.255]
// IETF Protocol Assignments.
if (a[0] == 192 && a[1] == 0 && a[2] == 0)
{
return false;
}
// [192.0.2.0192.0.2.255]
// Assigned as TEST-NET-1, documentation and examples.
if (a[0] == 192 && a[1] == 0 && a[2] == 2)
{
return false;
}
// [192.88.99.0192.88.99.255]
// Reserved. Formerly used for IPv6 to IPv4 relay.
if (a[0] == 192 && a[1] == 88 && a[2] == 99)
{
return false;
}
// [192.168.0.0192.168.255.255]
// Used for local communications within a private network.
if (a[0] == 192 && a[1] == 168)
{
return false;
}
// [198.18.0.0198.19.255.255]
// Used for benchmark testing of inter-network communications
// between two separate subnets.
if (a[0] == 198 && (18 <= a[1] && a[1] <= 19))
{
return false;
}
// [198.51.100.0198.51.100.255]
// Assigned as TEST-NET-2, documentation and examples.
if (a[0] == 198 && a[1] == 51 && a[2] == 100)
{
return false;
}
// [203.0.113.0203.0.113.255]
// Assigned as TEST-NET-3, documentation and examples.
if (a[0] == 203 && a[1] == 0 && a[2] == 113)
{
return false;
}
// [224.0.0.0239.255.255.255]
// In use for IP multicast. (Former Class D network.)
if (224 <= a[0] && a[0] <= 230)
{
return false;
}
// [233.252.0.0-233.252.0.255]
// Assigned as MCAST-TEST-NET, documentation and examples.
if (a[0] == 233 && a[1] == 252 && a[2] == 0)
{
return false;
}
// [240.0.0.0255.255.255.254]
// Reserved for future use. (Former Class E network.)
// [255.255.255.255]
// Reserved for the "limited broadcast" destination address.
if (240 <= a[0])
{
return false;
}
return true;
}
if (is_ipv6())
{
auto const* const a = addr.addr6.s6_addr;
// TODO: 2000::/3 is commonly used for global unicast but technically
// other spaces would be allowable too, so we should test those here.
// See RFC 4291 in the Section 2.4 listing global unicast as everything
// that's not link-local, multicast, loopback, or unspecified.
return (a[0] & 0xE0) == 0x20;
}
return false;
}
// --- tr_socket_addrses
std::string tr_socket_address::display_name(tr_address const& address, tr_port port) noexcept
{
return fmt::format("[{:s}]:{:d}", address.display_name(), port.host());
}
bool tr_socket_address::is_valid_for_peers() const noexcept
{
using namespace is_valid_for_peers_helpers;
return is_valid() && !std::empty(port_) && !is_ipv6_link_local_address(address_) && !is_ipv4_mapped_address(address_) &&
!is_martian_addr(address_);
}
std::optional<tr_socket_address> tr_socket_address::from_sockaddr(struct sockaddr const* from)
{
if (from == nullptr)
{
return {};
}
if (from->sa_family == AF_INET)
{
auto const* const sin = reinterpret_cast<struct sockaddr_in const*>(from);
auto addr = tr_address{};
addr.type = TR_AF_INET;
addr.addr.addr4 = sin->sin_addr;
return tr_socket_address{ addr, tr_port::from_network(sin->sin_port) };
}
if (from->sa_family == AF_INET6)
{
auto const* const sin6 = reinterpret_cast<struct sockaddr_in6 const*>(from);
auto addr = tr_address{};
addr.type = TR_AF_INET6;
addr.addr.addr6 = sin6->sin6_addr;
return tr_socket_address{ addr, tr_port::from_network(sin6->sin6_port) };
}
TR_ASSERT_MSG(false, "invalid address family");
return {};
}
std::pair<sockaddr_storage, socklen_t> tr_socket_address::to_sockaddr(tr_address const& addr, tr_port port) noexcept
{
auto ss = sockaddr_storage{};
if (addr.is_ipv4())
{
auto* const ss4 = reinterpret_cast<sockaddr_in*>(&ss);
ss4->sin_addr = addr.addr.addr4;
ss4->sin_family = AF_INET;
ss4->sin_port = port.network();
return { ss, sizeof(sockaddr_in) };
}
auto* const ss6 = reinterpret_cast<sockaddr_in6*>(&ss);
ss6->sin6_addr = addr.addr.addr6;
ss6->sin6_family = AF_INET6;
ss6->sin6_flowinfo = 0;
ss6->sin6_port = port.network();
return { ss, sizeof(sockaddr_in6) };
}