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transmission/libtransmission/net.c

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/******************************************************************************
* Copyright (c) Transmission authors and contributors
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*****************************************************************************/
#include <errno.h>
#include <string.h>
#include <assert.h>
#include <sys/types.h>
#ifdef _WIN32
#include <ws2tcpip.h>
#else
#include <netinet/tcp.h> /* TCP_CONGESTION */
#endif
#include <event2/util.h>
#include <libutp/utp.h>
#include "transmission.h"
#include "fdlimit.h" /* tr_fdSocketClose () */
#include "net.h"
#include "peer-io.h" /* tr_peerIoAddrStr () FIXME this should be moved to net.h */
#include "session.h" /* tr_sessionGetPublicAddress () */
#include "tr-utp.h" /* tr_utpSendTo () */
#include "log.h"
#include "utils.h" /* tr_time (), tr_logAddDebug () */
#ifndef IN_MULTICAST
#define IN_MULTICAST(a) (((a) & 0xf0000000) == 0xe0000000)
#endif
tr_address const tr_in6addr_any = { TR_AF_INET6, { IN6ADDR_ANY_INIT } };
tr_address const tr_inaddr_any = { TR_AF_INET, { { { { INADDR_ANY, 0x00, 0x00, 0x00 } } } } };
char* tr_net_strerror(char* buf, size_t buflen, int err)
{
*buf = '\0';
#ifdef _WIN32
DWORD len = FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM, NULL, err, 0, buf, buflen, NULL);
while (len > 0 && buf[len - 1] >= '\0' && buf[len - 1] <= ' ')
{
buf[--len] = '\0';
}
#else
tr_strlcpy(buf, tr_strerror(err), buflen);
#endif
return buf;
}
char const* tr_address_to_string_with_buf(tr_address const* addr, char* buf, size_t buflen)
{
assert(tr_address_is_valid(addr));
if (addr->type == TR_AF_INET)
{
return evutil_inet_ntop(AF_INET, &addr->addr, buf, buflen);
}
else
{
return evutil_inet_ntop(AF_INET6, &addr->addr, buf, buflen);
}
}
/*
* Non-threadsafe version of tr_address_to_string_with_buf ()
* and uses a static memory area for a buffer.
* This function is suitable to be called from libTransmission's networking code,
* which is single-threaded.
*/
char const* tr_address_to_string(tr_address const* addr)
{
static char buf[INET6_ADDRSTRLEN];
return tr_address_to_string_with_buf(addr, buf, sizeof(buf));
}
bool tr_address_from_string(tr_address* dst, char const* src)
{
bool ok;
if ((ok = evutil_inet_pton(AF_INET, src, &dst->addr) == 1))
{
dst->type = TR_AF_INET;
}
if (!ok) /* try IPv6 */
{
if ((ok = evutil_inet_pton(AF_INET6, src, &dst->addr) == 1))
{
dst->type = TR_AF_INET6;
}
}
return ok;
}
/*
* Compare two tr_address structures.
* Returns:
* <0 if a < b
* >0 if a > b
* 0 if a == b
*/
int tr_address_compare(tr_address const* a, tr_address const* b)
{
static int const sizes[2] = { sizeof(struct in_addr), sizeof(struct in6_addr) };
/* IPv6 addresses are always "greater than" IPv4 */
if (a->type != b->type)
{
return a->type == TR_AF_INET ? 1 : -1;
}
return memcmp(&a->addr, &b->addr, sizes[a->type]);
}
/***********************************************************************
* TCP sockets
**********************************************************************/
void tr_netSetTOS(tr_socket_t s, int tos)
{
#if defined(IP_TOS) && !defined(_WIN32)
if (setsockopt(s, IPPROTO_IP, IP_TOS, (void const*)&tos, sizeof(tos)) == -1)
{
char err_buf[512];
tr_logAddNamedInfo("Net", "Can't set TOS '%d': %s", tos, tr_net_strerror(err_buf, sizeof(err_buf), sockerrno));
}
#else
(void)s;
(void)tos;
#endif
}
void tr_netSetCongestionControl(tr_socket_t s, char const* algorithm)
{
#ifdef TCP_CONGESTION
if (setsockopt(s, IPPROTO_TCP, TCP_CONGESTION, (void const*)algorithm, strlen(algorithm) + 1) == -1)
{
char err_buf[512];
tr_logAddNamedInfo("Net", "Can't set congestion control algorithm '%s': %s", algorithm, tr_net_strerror(err_buf,
sizeof(err_buf), sockerrno));
}
#else
(void)s;
(void)algorithm;
#endif
}
bool tr_address_from_sockaddr_storage(tr_address* setme_addr, tr_port* setme_port, struct sockaddr_storage const* from)
{
if (from->ss_family == AF_INET)
{
struct sockaddr_in* sin = (struct sockaddr_in*)from;
setme_addr->type = TR_AF_INET;
setme_addr->addr.addr4.s_addr = sin->sin_addr.s_addr;
*setme_port = sin->sin_port;
return true;
}
if (from->ss_family == AF_INET6)
{
struct sockaddr_in6* sin6 = (struct sockaddr_in6*)from;
setme_addr->type = TR_AF_INET6;
setme_addr->addr.addr6 = sin6->sin6_addr;
*setme_port = sin6->sin6_port;
return true;
}
return false;
}
static socklen_t setup_sockaddr(tr_address const* addr, tr_port port, struct sockaddr_storage* sockaddr)
{
assert(tr_address_is_valid(addr));
if (addr->type == TR_AF_INET)
{
struct sockaddr_in sock4;
memset(&sock4, 0, sizeof(sock4));
sock4.sin_family = AF_INET;
sock4.sin_addr.s_addr = addr->addr.addr4.s_addr;
sock4.sin_port = port;
memcpy(sockaddr, &sock4, sizeof(sock4));
return sizeof(struct sockaddr_in);
}
else
{
struct sockaddr_in6 sock6;
memset(&sock6, 0, sizeof(sock6));
sock6.sin6_family = AF_INET6;
sock6.sin6_port = port;
sock6.sin6_flowinfo = 0;
sock6.sin6_addr = addr->addr.addr6;
memcpy(sockaddr, &sock6, sizeof(sock6));
return sizeof(struct sockaddr_in6);
}
}
tr_socket_t tr_netOpenPeerSocket(tr_session* session, tr_address const* addr, tr_port port, bool clientIsSeed)
{
static int const domains[NUM_TR_AF_INET_TYPES] = { AF_INET, AF_INET6 };
tr_socket_t s;
struct sockaddr_storage sock;
socklen_t addrlen;
tr_address const* source_addr;
socklen_t sourcelen;
struct sockaddr_storage source_sock;
char err_buf[512];
assert(tr_address_is_valid(addr));
if (!tr_address_is_valid_for_peers(addr, port))
{
return TR_BAD_SOCKET; /* -EINVAL */
}
s = tr_fdSocketCreate(session, domains[addr->type], SOCK_STREAM);
if (s == TR_BAD_SOCKET)
{
return TR_BAD_SOCKET;
}
/* seeds don't need much of a read buffer... */
if (clientIsSeed)
{
int n = 8192;
if (setsockopt(s, SOL_SOCKET, SO_RCVBUF, (void const*)&n, sizeof(n)))
{
tr_logAddInfo("Unable to set SO_RCVBUF on socket %" PRIdMAX ": %s", (intmax_t)s,
tr_net_strerror(err_buf, sizeof(err_buf), sockerrno));
}
}
if (evutil_make_socket_nonblocking(s) < 0)
{
tr_netClose(session, s);
return TR_BAD_SOCKET;
}
addrlen = setup_sockaddr(addr, port, &sock);
/* set source address */
source_addr = tr_sessionGetPublicAddress(session, addr->type, NULL);
assert(source_addr);
sourcelen = setup_sockaddr(source_addr, 0, &source_sock);
if (bind(s, (struct sockaddr*)&source_sock, sourcelen))
{
tr_logAddError(_("Couldn't set source address %s on %" PRIdMAX ": %s"), tr_address_to_string(source_addr), (intmax_t)s,
tr_net_strerror(err_buf, sizeof(err_buf), sockerrno));
tr_netClose(session, s);
return TR_BAD_SOCKET; /* -errno */
}
if ((connect(s, (struct sockaddr*)&sock, addrlen) < 0) &&
#ifdef _WIN32
(sockerrno != WSAEWOULDBLOCK) &&
#endif
(sockerrno != EINPROGRESS))
{
int tmperrno;
tmperrno = sockerrno;
if ((tmperrno != ENETUNREACH && tmperrno != EHOSTUNREACH) || addr->type == TR_AF_INET)
{
tr_logAddError(_("Couldn't connect socket %" PRIdMAX " to %s, port %d (errno %d - %s)"), (intmax_t)s,
tr_address_to_string(addr), (int)ntohs(port), tmperrno, tr_net_strerror(err_buf, sizeof(err_buf), tmperrno));
}
tr_netClose(session, s);
s = TR_BAD_SOCKET; /* -tmperrno */
}
tr_logAddDeep(__FILE__, __LINE__, NULL, "New OUTGOING connection %" PRIdMAX " (%s)", (intmax_t)s,
tr_peerIoAddrStr(addr, port));
return s;
}
struct UTPSocket* tr_netOpenPeerUTPSocket(tr_session* session, tr_address const* addr, tr_port port, bool clientIsSeed UNUSED)
{
struct UTPSocket* ret = NULL;
if (tr_address_is_valid_for_peers(addr, port))
{
struct sockaddr_storage ss;
socklen_t const sslen = setup_sockaddr(addr, port, &ss);
ret = UTP_Create(tr_utpSendTo, session, (struct sockaddr*)&ss, sslen);
}
return ret;
}
static tr_socket_t tr_netBindTCPImpl(tr_address const* addr, tr_port port, bool suppressMsgs, int* errOut)
{
static int const domains[NUM_TR_AF_INET_TYPES] = { AF_INET, AF_INET6 };
struct sockaddr_storage sock;
tr_socket_t fd;
int addrlen;
int optval;
assert(tr_address_is_valid(addr));
fd = socket(domains[addr->type], SOCK_STREAM, 0);
if (fd == TR_BAD_SOCKET)
{
*errOut = sockerrno;
return TR_BAD_SOCKET;
}
if (evutil_make_socket_nonblocking(fd) < 0)
{
*errOut = sockerrno;
tr_netCloseSocket(fd);
return TR_BAD_SOCKET;
}
optval = 1;
setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, (void const*)&optval, sizeof(optval));
setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (void const*)&optval, sizeof(optval));
#ifdef IPV6_V6ONLY
if (addr->type == TR_AF_INET6)
{
if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, (void const*)&optval, sizeof(optval)) == -1)
{
if (sockerrno != ENOPROTOOPT) /* if the kernel doesn't support it, ignore it */
{
*errOut = sockerrno;
tr_netCloseSocket(fd);
return TR_BAD_SOCKET;
}
}
}
#endif
addrlen = setup_sockaddr(addr, htons(port), &sock);
if (bind(fd, (struct sockaddr*)&sock, addrlen))
{
int const err = sockerrno;
if (!suppressMsgs)
{
char const* fmt;
char const* hint;
char err_buf[512];
if (err == EADDRINUSE)
{
hint = _("Is another copy of Transmission already running?");
}
else
{
hint = NULL;
}
if (hint == NULL)
{
fmt = _("Couldn't bind port %d on %s: %s");
}
else
{
fmt = _("Couldn't bind port %d on %s: %s (%s)");
}
tr_logAddError(fmt, port, tr_address_to_string(addr), tr_net_strerror(err_buf, sizeof(err_buf), err), hint);
}
tr_netCloseSocket(fd);
*errOut = err;
return TR_BAD_SOCKET;
}
if (!suppressMsgs)
{
tr_logAddDebug("Bound socket %" PRIdMAX " to port %d on %s", (intmax_t)fd, port, tr_address_to_string(addr));
}
#ifdef TCP_FASTOPEN
#ifndef SOL_TCP
#define SOL_TCP IPPROTO_TCP
#endif
optval = 5;
setsockopt(fd, SOL_TCP, TCP_FASTOPEN, (void const*)&optval, sizeof(optval));
#endif
if (listen(fd, 128) == -1)
{
*errOut = sockerrno;
tr_netCloseSocket(fd);
return TR_BAD_SOCKET;
}
return fd;
}
tr_socket_t tr_netBindTCP(tr_address const* addr, tr_port port, bool suppressMsgs)
{
int unused;
return tr_netBindTCPImpl(addr, port, suppressMsgs, &unused);
}
bool tr_net_hasIPv6(tr_port port)
{
static bool result = false;
static bool alreadyDone = false;
if (!alreadyDone)
{
int err;
tr_socket_t fd = tr_netBindTCPImpl(&tr_in6addr_any, port, true, &err);
if (fd != TR_BAD_SOCKET || err != EAFNOSUPPORT) /* we support ipv6 */
{
result = true;
}
if (fd != TR_BAD_SOCKET)
{
tr_netCloseSocket(fd);
}
alreadyDone = true;
}
return result;
}
tr_socket_t tr_netAccept(tr_session* session, tr_socket_t b, tr_address* addr, tr_port* port)
{
tr_socket_t fd = tr_fdSocketAccept(session, b, addr, port);
if (fd != TR_BAD_SOCKET && evutil_make_socket_nonblocking(fd) < 0)
{
tr_netClose(session, fd);
fd = TR_BAD_SOCKET;
}
return fd;
}
void tr_netCloseSocket(tr_socket_t fd)
{
evutil_closesocket(fd);
}
void tr_netClose(tr_session* session, tr_socket_t s)
{
tr_fdSocketClose(session, s);
}
/*
get_source_address () and global_unicast_address () were written by
Juliusz Chroboczek, and are covered under the same license as dht.c.
Please feel free to copy them into your software if it can help
unbreaking the double-stack Internet. */
/* Get the source address used for a given destination address. Since
there is no official interface to get this information, we create
a connected UDP socket (connected UDP... hmm...) and check its source
address. */
static int get_source_address(struct sockaddr const* dst, socklen_t dst_len, struct sockaddr* src, socklen_t* src_len)
{
tr_socket_t s;
int rc, save;
s = socket(dst->sa_family, SOCK_DGRAM, 0);
if (s == TR_BAD_SOCKET)
{
goto fail;
}
/* Since it's a UDP socket, this doesn't actually send any packets. */
rc = connect(s, dst, dst_len);
if (rc < 0)
{
goto fail;
}
rc = getsockname(s, src, src_len);
if (rc < 0)
{
goto fail;
}
evutil_closesocket(s);
return rc;
fail:
save = errno;
evutil_closesocket(s);
errno = save;
return -1;
}
/* We all hate NATs. */
static int global_unicast_address(struct sockaddr* sa)
{
if (sa->sa_family == AF_INET)
{
unsigned char const* a = (unsigned char*)&((struct sockaddr_in*)sa)->sin_addr;
if (a[0] == 0 || a[0] == 127 || a[0] >= 224 || a[0] == 10 || (a[0] == 172 && a[1] >= 16 && a[1] <= 31) ||
(a[0] == 192 && a[1] == 168))
{
return 0;
}
return 1;
}
else if (sa->sa_family == AF_INET6)
{
unsigned char const* a = (unsigned char*)&((struct sockaddr_in6*)sa)->sin6_addr;
/* 2000::/3 */
return (a[0] & 0xE0) == 0x20;
}
else
{
errno = EAFNOSUPPORT;
return -1;
}
}
static int tr_globalAddress(int af, void* addr, int* addr_len)
{
struct sockaddr_storage ss;
socklen_t sslen = sizeof(ss);
struct sockaddr_in sin;
struct sockaddr_in6 sin6;
struct sockaddr* sa;
socklen_t salen;
int rc;
switch (af)
{
case AF_INET:
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
evutil_inet_pton(AF_INET, "91.121.74.28", &sin.sin_addr);
sin.sin_port = htons(6969);
sa = (struct sockaddr*)&sin;
salen = sizeof(sin);
break;
case AF_INET6:
memset(&sin6, 0, sizeof(sin6));
sin6.sin6_family = AF_INET6;
/* In order for address selection to work right, this should be
a native IPv6 address, not Teredo or 6to4. */
evutil_inet_pton(AF_INET6, "2001:1890:1112:1::20", &sin6.sin6_addr);
sin6.sin6_port = htons(6969);
sa = (struct sockaddr*)&sin6;
salen = sizeof(sin6);
break;
default:
return -1;
}
rc = get_source_address(sa, salen, (struct sockaddr*)&ss, &sslen);
if (rc < 0)
{
return -1;
}
if (!global_unicast_address((struct sockaddr*)&ss))
{
return -1;
}
switch (af)
{
case AF_INET:
if (*addr_len < 4)
{
return -1;
}
memcpy(addr, &((struct sockaddr_in*)&ss)->sin_addr, 4);
*addr_len = 4;
return 1;
case AF_INET6:
if (*addr_len < 16)
{
return -1;
}
memcpy(addr, &((struct sockaddr_in6*)&ss)->sin6_addr, 16);
*addr_len = 16;
return 1;
default:
return -1;
}
}
/* Return our global IPv6 address, with caching. */
unsigned char const* tr_globalIPv6(void)
{
static unsigned char ipv6[16];
static time_t last_time = 0;
static bool have_ipv6 = false;
time_t const now = tr_time();
/* Re-check every half hour */
if (last_time < now - 1800)
{
int addrlen = 16;
int const rc = tr_globalAddress(AF_INET6, ipv6, &addrlen);
have_ipv6 = (rc >= 0) && (addrlen == 16);
last_time = now;
}
return have_ipv6 ? ipv6 : NULL;
}
/***
****
****
***/
static bool isIPv4MappedAddress(tr_address const* addr)
{
return (addr->type == TR_AF_INET6) && IN6_IS_ADDR_V4MAPPED(&addr->addr.addr6);
}
static bool isIPv6LinkLocalAddress(tr_address const* addr)
{
return (addr->type == TR_AF_INET6) && 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. */
static bool isMartianAddr(struct tr_address const* a)
{
static unsigned char const zeroes[16] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
assert(tr_address_is_valid(a));
switch (a->type)
{
case TR_AF_INET:
{
unsigned char const* address = (unsigned char const*)&a->addr.addr4;
return (address[0] == 0) || (address[0] == 127) || ((address[0] & 0xE0) == 0xE0);
}
case TR_AF_INET6:
{
unsigned char const* address = (unsigned char const*)&a->addr.addr6;
return (address[0] == 0xFF) || (memcmp(address, zeroes, 15) == 0 && (address[15] == 0 || address[15] == 1));
}
default:
return true;
}
}
bool tr_address_is_valid_for_peers(tr_address const* addr, tr_port port)
{
return (port != 0) && (tr_address_is_valid(addr)) && (!isIPv6LinkLocalAddress(addr)) && (!isIPv4MappedAddress(addr)) &&
(!isMartianAddr(addr));
}
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