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/*
net_socket.c -- Handle various kinds of sockets.
Copyright (C) 1998-2005 Ivo Timmermans,
2000-2012 Guus Sliepen <guus@tinc-vpn.org>
2006 Scott Lamb <slamb@slamb.org>
2009 Florian Forster <octo@verplant.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "system.h"
#include "avl_tree.h"
#include "conf.h"
#include "connection.h"
#include "event.h"
#include "logger.h"
#include "meta.h"
#include "net.h"
#include "netutl.h"
#include "protocol.h"
#include "utils.h"
#include "xalloc.h"
/* Needed on Mac OS/X */
#ifndef SOL_TCP
#define SOL_TCP IPPROTO_TCP
#endif
int addressfamily = AF_UNSPEC;
int maxtimeout = 900;
int seconds_till_retry = 5;
int udp_rcvbuf = 0;
int udp_sndbuf = 0;
listen_socket_t listen_socket[MAXSOCKETS];
int listen_sockets;
list_t *outgoing_list = NULL;
/* Setup sockets */
static void configure_tcp(connection_t *c) {
int option;
#ifdef O_NONBLOCK
int flags = fcntl(c->socket, F_GETFL);
if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
logger(LOG_ERR, "fcntl for %s: %s", c->hostname, strerror(errno));
}
#elif defined(WIN32)
unsigned long arg = 1;
if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) {
logger(LOG_ERR, "ioctlsocket for %s: %d", c->hostname, sockstrerror(sockerrno));
}
#endif
#if defined(SOL_TCP) && defined(TCP_NODELAY)
option = 1;
setsockopt(c->socket, SOL_TCP, TCP_NODELAY, (void *)&option, sizeof(option));
#endif
#if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY)
option = IPTOS_LOWDELAY;
setsockopt(c->socket, SOL_IP, IP_TOS, (void *)&option, sizeof(option));
#endif
}
static bool bind_to_interface(int sd) {
char *iface;
#if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
struct ifreq ifr;
int status;
#endif /* defined(SOL_SOCKET) && defined(SO_BINDTODEVICE) */
if(!get_config_string (lookup_config (config_tree, "BindToInterface"), &iface))
return true;
#if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
memset(&ifr, 0, sizeof(ifr));
strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
status = setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr));
if(status) {
logger(LOG_ERR, "Can't bind to interface %s: %s", iface,
strerror(errno));
return false;
}
#else /* if !defined(SOL_SOCKET) || !defined(SO_BINDTODEVICE) */
logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface");
#endif
return true;
}
int setup_listen_socket(const sockaddr_t *sa) {
int nfd;
char *addrstr;
int option;
char *iface;
nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
if(nfd < 0) {
ifdebug(STATUS) logger(LOG_ERR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
return -1;
}
#ifdef FD_CLOEXEC
fcntl(nfd, F_SETFD, FD_CLOEXEC);
#endif
/* Optimize TCP settings */
option = 1;
setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
#if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
if(sa->sa.sa_family == AF_INET6)
setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
#endif
if(get_config_string
(lookup_config(config_tree, "BindToInterface"), &iface)) {
#if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
struct ifreq ifr;
memset(&ifr, 0, sizeof(ifr));
strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr))) {
closesocket(nfd);
logger(LOG_ERR, "Can't bind to interface %s: %s", iface,
strerror(sockerrno));
return -1;
}
#else
logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface");
#endif
}
if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
closesocket(nfd);
addrstr = sockaddr2hostname(sa);
logger(LOG_ERR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
free(addrstr);
return -1;
}
if(listen(nfd, 3)) {
closesocket(nfd);
logger(LOG_ERR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
return -1;
}
return nfd;
}
int setup_vpn_in_socket(const sockaddr_t *sa) {
int nfd;
char *addrstr;
int option;
nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
if(nfd < 0) {
logger(LOG_ERR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
return -1;
}
#ifdef FD_CLOEXEC
fcntl(nfd, F_SETFD, FD_CLOEXEC);
#endif
#ifdef O_NONBLOCK
{
int flags = fcntl(nfd, F_GETFL);
if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
closesocket(nfd);
logger(LOG_ERR, "System call `%s' failed: %s", "fcntl",
strerror(errno));
return -1;
}
}
#elif defined(WIN32)
{
unsigned long arg = 1;
if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
closesocket(nfd);
logger(LOG_ERR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
return -1;
}
}
#endif
option = 1;
setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
setsockopt(nfd, SOL_SOCKET, SO_BROADCAST, (void *)&option, sizeof(option));
if(udp_rcvbuf && setsockopt(nfd, SOL_SOCKET, SO_RCVBUF, (void *)&udp_rcvbuf, sizeof(udp_rcvbuf)))
logger(LOG_WARNING, "Can't set UDP SO_RCVBUF to %i: %s", udp_rcvbuf, strerror(errno));
if(udp_sndbuf && setsockopt(nfd, SOL_SOCKET, SO_SNDBUF, (void *)&udp_sndbuf, sizeof(udp_sndbuf)))
logger(LOG_WARNING, "Can't set UDP SO_SNDBUF to %i: %s", udp_sndbuf, strerror(errno));
#if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
if(sa->sa.sa_family == AF_INET6)
setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
#endif
#if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
#define IP_DONTFRAGMENT IP_DONTFRAG
#endif
#if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
if(myself->options & OPTION_PMTU_DISCOVERY) {
option = IP_PMTUDISC_DO;
setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
}
#elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT)
if(myself->options & OPTION_PMTU_DISCOVERY) {
option = 1;
setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
}
#else
#warning No way to disable IPv4 fragmentation
#endif
#if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
if(myself->options & OPTION_PMTU_DISCOVERY) {
option = IPV6_PMTUDISC_DO;
setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
}
#elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
if(myself->options & OPTION_PMTU_DISCOVERY) {
option = 1;
setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
}
#else
#warning No way to disable IPv6 fragmentation
#endif
if (!bind_to_interface(nfd)) {
closesocket(nfd);
return -1;
}
if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
closesocket(nfd);
addrstr = sockaddr2hostname(sa);
logger(LOG_ERR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
free(addrstr);
return -1;
}
return nfd;
} /* int setup_vpn_in_socket */
void retry_outgoing(outgoing_t *outgoing) {
outgoing->timeout += 5;
if(outgoing->timeout > maxtimeout)
outgoing->timeout = maxtimeout;
if(outgoing->event)
event_del(outgoing->event);
outgoing->event = new_event();
outgoing->event->handler = (event_handler_t) setup_outgoing_connection;
outgoing->event->time = now + outgoing->timeout;
outgoing->event->data = outgoing;
event_add(outgoing->event);
ifdebug(CONNECTIONS) logger(LOG_NOTICE,
"Trying to re-establish outgoing connection in %d seconds",
outgoing->timeout);
}
void finish_connecting(connection_t *c) {
ifdebug(CONNECTIONS) logger(LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
if(proxytype != PROXY_EXEC)
configure_tcp(c);
c->last_ping_time = now;
send_id(c);
}
static void do_outgoing_pipe(connection_t *c, char *command) {
#ifndef HAVE_MINGW
int fd[2];
if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd)) {
logger(LOG_ERR, "Could not create socketpair: %s\n", strerror(errno));
return;
}
if(fork()) {
c->socket = fd[0];
close(fd[1]);
logger(LOG_DEBUG, "Using proxy %s", command);
return;
}
close(0);
close(1);
close(fd[0]);
dup2(fd[1], 0);
dup2(fd[1], 1);
close(fd[1]);
// Other filedescriptors should be closed automatically by CLOEXEC
char *host = NULL;
char *port = NULL;
sockaddr2str(&c->address, &host, &port);
setenv("REMOTEADDRESS", host, true);
setenv("REMOTEPORT", port, true);
setenv("NODE", c->name, true);
setenv("NAME", myself->name, true);
if(netname)
setenv("NETNAME", netname, true);
int result = system(command);
if(result < 0)
logger(LOG_ERR, "Could not execute %s: %s\n", command, strerror(errno));
else if(result)
logger(LOG_ERR, "%s exited with non-zero status %d", command, result);
exit(result);
#else
logger(LOG_ERR, "Proxy type exec not supported on this platform!");
return;
#endif
}
void do_outgoing_connection(connection_t *c) {
char *address, *port, *space;
struct addrinfo *proxyai = NULL;
int result;
if(!c->outgoing) {
logger(LOG_ERR, "do_outgoing_connection() for %s called without c->outgoing", c->name);
abort();
}
begin:
if(!c->outgoing->ai) {
if(!c->outgoing->cfg) {
ifdebug(CONNECTIONS) logger(LOG_ERR, "Could not set up a meta connection to %s",
c->name);
c->status.remove = true;
retry_outgoing(c->outgoing);
c->outgoing = NULL;
return;
}
get_config_string(c->outgoing->cfg, &address);
space = strchr(address, ' ');
if(space) {
port = xstrdup(space + 1);
*space = 0;
} else {
if(!get_config_string(lookup_config(c->config_tree, "Port"), &port))
port = xstrdup("655");
}
c->outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
free(address);
free(port);
c->outgoing->aip = c->outgoing->ai;
c->outgoing->cfg = lookup_config_next(c->config_tree, c->outgoing->cfg);
}
if(!c->outgoing->aip) {
if(c->outgoing->ai)
freeaddrinfo(c->outgoing->ai);
c->outgoing->ai = NULL;
goto begin;
}
memcpy(&c->address, c->outgoing->aip->ai_addr, c->outgoing->aip->ai_addrlen);
c->outgoing->aip = c->outgoing->aip->ai_next;
if(c->hostname)
free(c->hostname);
c->hostname = sockaddr2hostname(&c->address);
ifdebug(CONNECTIONS) logger(LOG_INFO, "Trying to connect to %s (%s)", c->name,
c->hostname);
if(!proxytype) {
c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
configure_tcp(c);
} else if(proxytype == PROXY_EXEC) {
do_outgoing_pipe(c, proxyhost);
} else {
proxyai = str2addrinfo(proxyhost, proxyport, SOCK_STREAM);
if(!proxyai)
goto begin;
ifdebug(CONNECTIONS) logger(LOG_INFO, "Using proxy at %s port %s", proxyhost, proxyport);
c->socket = socket(proxyai->ai_family, SOCK_STREAM, IPPROTO_TCP);
}
if(c->socket == -1) {
ifdebug(CONNECTIONS) logger(LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
goto begin;
}
#ifdef FD_CLOEXEC
fcntl(c->socket, F_SETFD, FD_CLOEXEC);
#endif
if(proxytype != PROXY_EXEC) {
#if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
int option = 1;
if(c->address.sa.sa_family == AF_INET6)
setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, (void *)&option, sizeof option);
#endif
bind_to_interface(c->socket);
}
/* Connect */
if(!proxytype) {
result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
} else if(proxytype == PROXY_EXEC) {
result = 0;
} else {
result = connect(c->socket, proxyai->ai_addr, proxyai->ai_addrlen);
freeaddrinfo(proxyai);
}
if(result == -1) {
if(sockinprogress(sockerrno)) {
c->status.connecting = true;
return;
}
closesocket(c->socket);
ifdebug(CONNECTIONS) logger(LOG_ERR, "%s: %s", c->hostname, sockstrerror(sockerrno));
goto begin;
}
finish_connecting(c);
return;
}
void setup_outgoing_connection(outgoing_t *outgoing) {
connection_t *c;
node_t *n;
outgoing->event = NULL;
n = lookup_node(outgoing->name);
if(n)
if(n->connection) {
ifdebug(CONNECTIONS) logger(LOG_INFO, "Already connected to %s", outgoing->name);
n->connection->outgoing = outgoing;
return;
}
c = new_connection();
c->name = xstrdup(outgoing->name);
c->outcipher = myself->connection->outcipher;
c->outdigest = myself->connection->outdigest;
c->outmaclength = myself->connection->outmaclength;
c->outcompression = myself->connection->outcompression;
init_configuration(&c->config_tree);
read_connection_config(c);
outgoing->cfg = lookup_config(c->config_tree, "Address");
if(!outgoing->cfg) {
logger(LOG_ERR, "No address specified for %s", c->name);
free_connection(c);
return;
}
c->outgoing = outgoing;
c->last_ping_time = now;
connection_add(c);
do_outgoing_connection(c);
}
/*
accept a new tcp connect and create a
new connection
*/
bool handle_new_meta_connection(int sock) {
connection_t *c;
sockaddr_t sa;
int fd;
socklen_t len = sizeof(sa);
fd = accept(sock, &sa.sa, &len);
if(fd < 0) {
logger(LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
return false;
}
sockaddrunmap(&sa);
c = new_connection();
c->name = xstrdup("<unknown>");
c->outcipher = myself->connection->outcipher;
c->outdigest = myself->connection->outdigest;
c->outmaclength = myself->connection->outmaclength;
c->outcompression = myself->connection->outcompression;
c->address = sa;
c->hostname = sockaddr2hostname(&sa);
c->socket = fd;
c->last_ping_time = now;
ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection from %s", c->hostname);
configure_tcp(c);
connection_add(c);
c->allow_request = ID;
send_id(c);
return true;
}
static void free_outgoing(outgoing_t *outgoing) {
if(outgoing->ai)
freeaddrinfo(outgoing->ai);
if(outgoing->name)
free(outgoing->name);
free(outgoing);
}
void try_outgoing_connections(void) {
static config_t *cfg = NULL;
char *name;
outgoing_t *outgoing;
outgoing_list = list_alloc((list_action_t)free_outgoing);
for(cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
get_config_string(cfg, &name);
if(!check_id(name)) {
logger(LOG_ERR,
"Invalid name for outgoing connection in %s line %d",
cfg->file, cfg->line);
free(name);
continue;
}
outgoing = xmalloc_and_zero(sizeof(*outgoing));
outgoing->name = name;
list_insert_tail(outgoing_list, outgoing);
setup_outgoing_connection(outgoing);
}
}
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