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- /*
- net_socket.c -- Handle various kinds of sockets.
- Copyright (C) 1998-2005 Ivo Timmermans,
- 2000-2017 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 "proxy.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 mintimeout = 0;
- 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: %s", 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(IP_TOS) && defined(IPTOS_LOWDELAY)
- option = IPTOS_LOWDELAY;
- setsockopt(c->socket, IPPROTO_IP, IP_TOS, (void *)&option, sizeof(option));
- #endif
- #if defined(IPV6_TCLASS) && defined(IPTOS_LOWDELAY)
- option = IPTOS_LOWDELAY;
- setsockopt(c->socket, IPPROTO_IPV6, IPV6_TCLASS, (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;
- free(iface);
- status = setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr));
- if(status) {
- logger(LOG_ERR, "Can't bind to interface %s: %s", ifr.ifr_ifrn.ifrn_name, 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(IPV6_V6ONLY)
- if(sa->sa.sa_family == AF_INET6) {
- setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
- }
- #else
- #warning IPV6_V6ONLY not defined
- #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);
- ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
- free(iface);
- if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr))) {
- closesocket(nfd);
- logger(LOG_ERR, "Can't bind to interface %s: %s", ifr.ifr_ifrn.ifrn_name, 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(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(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
- if(myself->options & OPTION_PMTU_DISCOVERY) {
- option = IP_PMTUDISC_DO;
- setsockopt(nfd, IPPROTO_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
- }
- #elif defined(IP_DONTFRAGMENT)
- if(myself->options & OPTION_PMTU_DISCOVERY) {
- option = 1;
- setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
- }
- #endif
- #if defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
- if(myself->options & OPTION_PMTU_DISCOVERY) {
- option = IPV6_PMTUDISC_DO;
- setsockopt(nfd, IPPROTO_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
- }
- #elif defined(IPV6_DONTFRAG)
- if(myself->options & OPTION_PMTU_DISCOVERY) {
- option = 1;
- setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
- }
- #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 < mintimeout) {
- outgoing->timeout = mintimeout;
- }
- 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);
- 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]);
- ifdebug(CONNECTIONS) 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
- }
- static bool is_valid_host_port(const char *host, const char *port) {
- for(const char *p = host; *p; p++)
- if(!isalnum(*p) && *p != '-' && *p != '.') {
- return false;
- }
- for(const char *p = port; *p; p++)
- if(!isalnum(*p)) {
- return false;
- }
- return true;
- }
- void do_outgoing_connection(connection_t *c) {
- 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;
- }
- char *address, *port, *space;
- 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);
- // If we cannot resolve the address, maybe we are using a proxy that can?
- if(!c->outgoing->ai && proxytype != PROXY_NONE && is_valid_host_port(address, port)) {
- memset(&c->address, 0, sizeof(c->address));
- c->address.sa.sa_family = AF_UNKNOWN;
- c->address.unknown.address = address;
- c->address.unknown.port = port;
- } else {
- 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->ai && proxytype != PROXY_NONE) {
- goto connect;
- }
- }
- 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;
- connect:
- 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);
- } else if(proxytype == PROXY_EXEC) {
- c->status.proxy_passed = true;
- 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;
- }
- if(proxytype != PROXY_EXEC) {
- configure_tcp(c);
- }
- #ifdef FD_CLOEXEC
- fcntl(c->socket, F_SETFD, FD_CLOEXEC);
- #endif
- if(proxytype != PROXY_EXEC) {
- #if defined(IPV6_V6ONLY)
- int option = 1;
- if(c->address.sa.sa_family == AF_INET6) {
- setsockopt(c->socket, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
- }
- #endif
- bind_to_interface(c->socket);
- int b = -1;
- for(int i = 0; i < listen_sockets; i++) {
- if(listen_socket[i].sa.sa.sa_family == c->address.sa.sa_family) {
- if(b == -1) {
- b = i;
- } else {
- b = -1;
- break;
- }
- }
- }
- if(b != -1) {
- sockaddr_t sa = listen_socket[b].sa;
- if(sa.sa.sa_family == AF_INET) {
- sa.in.sin_port = 0;
- } else if(sa.sa.sa_family == AF_INET6) {
- sa.in6.sin6_port = 0;
- }
- if(bind(c->socket, &sa.sa, SALEN(sa.sa))) {
- char *addrstr = sockaddr2hostname(&sa);
- logger(LOG_ERR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
- free(addrstr);
- }
- }
- }
- /* 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);
- }
- now = time(NULL);
- if(result == -1) {
- if(sockinprogress(sockerrno)) {
- c->last_ping_time = now;
- 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);
- if(!read_connection_config(c)) {
- free_connection(c);
- outgoing->timeout = maxtimeout;
- retry_outgoing(outgoing);
- return;
- }
- outgoing->cfg = lookup_config(c->config_tree, "Address");
- if(!outgoing->cfg) {
- logger(LOG_ERR, "No address specified for %s", c->name);
- free_connection(c);
- outgoing->timeout = maxtimeout;
- retry_outgoing(outgoing);
- 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) {
- static const int max_accept_burst = 10;
- static int last_accept_burst;
- static int last_accept_time;
- 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;
- }
- if(last_accept_time == now) {
- last_accept_burst++;
- if(last_accept_burst >= max_accept_burst) {
- if(last_accept_burst == max_accept_burst) {
- ifdebug(CONNECTIONS) logger(LOG_WARNING, "Throttling incoming connections");
- }
- tarpit(fd);
- return false;
- }
- } else {
- last_accept_burst = 0;
- last_accept_time = now;
- }
- 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;
- 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);
- }
- }
|