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tinc/src/net_setup.c
Guus Sliepen 5a28aa7b8b Add LocalDiscovery option which tries to detect peers on the local network. 
Currently, this is implemented by sending IPv4 broadcast packets to the
LAN during path MTU discovery.
2012-02-22 23:17:43 +01:00

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/*
net_setup.c -- Setup.
Copyright (C) 1998-2005 Ivo Timmermans,
2000-2012 Guus Sliepen <guus@tinc-vpn.org>
2006 Scott Lamb <slamb@slamb.org>
2010 Brandon Black <blblack@gmail.com>
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 <openssl/pem.h>
#include <openssl/rsa.h>
#include <openssl/rand.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include "avl_tree.h"
#include "conf.h"
#include "connection.h"
#include "device.h"
#include "event.h"
#include "graph.h"
#include "logger.h"
#include "net.h"
#include "netutl.h"
#include "process.h"
#include "protocol.h"
#include "route.h"
#include "subnet.h"
#include "utils.h"
#include "xalloc.h"
char *myport;
devops_t devops;
bool read_rsa_public_key(connection_t *c) {
FILE *fp;
char *fname;
char *key;
if(!c->rsa_key) {
c->rsa_key = RSA_new();
// RSA_blinding_on(c->rsa_key, NULL);
}
/* First, check for simple PublicKey statement */
if(get_config_string(lookup_config(c->config_tree, "PublicKey"), &key)) {
BN_hex2bn(&c->rsa_key->n, key);
BN_hex2bn(&c->rsa_key->e, "FFFF");
free(key);
return true;
}
/* Else, check for PublicKeyFile statement and read it */
if(get_config_string(lookup_config(c->config_tree, "PublicKeyFile"), &fname)) {
fp = fopen(fname, "r");
if(!fp) {
logger(LOG_ERR, "Error reading RSA public key file `%s': %s",
fname, strerror(errno));
free(fname);
return false;
}
free(fname);
c->rsa_key = PEM_read_RSAPublicKey(fp, &c->rsa_key, NULL, NULL);
fclose(fp);
if(c->rsa_key)
return true; /* Woohoo. */
/* If it fails, try PEM_read_RSA_PUBKEY. */
fp = fopen(fname, "r");
if(!fp) {
logger(LOG_ERR, "Error reading RSA public key file `%s': %s",
fname, strerror(errno));
free(fname);
return false;
}
free(fname);
c->rsa_key = PEM_read_RSA_PUBKEY(fp, &c->rsa_key, NULL, NULL);
fclose(fp);
if(c->rsa_key) {
// RSA_blinding_on(c->rsa_key, NULL);
return true;
}
logger(LOG_ERR, "Reading RSA public key file `%s' failed: %s",
fname, strerror(errno));
return false;
}
/* Else, check if a harnessed public key is in the config file */
xasprintf(&fname, "%s/hosts/%s", confbase, c->name);
fp = fopen(fname, "r");
if(!fp) {
logger(LOG_ERR, "Error reading RSA public key file `%s': %s", fname, strerror(errno));
free(fname);
return false;
}
c->rsa_key = PEM_read_RSAPublicKey(fp, &c->rsa_key, NULL, NULL);
fclose(fp);
free(fname);
if(c->rsa_key)
return true;
/* Try again with PEM_read_RSA_PUBKEY. */
xasprintf(&fname, "%s/hosts/%s", confbase, c->name);
fp = fopen(fname, "r");
if(!fp) {
logger(LOG_ERR, "Error reading RSA public key file `%s': %s", fname, strerror(errno));
free(fname);
return false;
}
c->rsa_key = PEM_read_RSA_PUBKEY(fp, &c->rsa_key, NULL, NULL);
// RSA_blinding_on(c->rsa_key, NULL);
fclose(fp);
free(fname);
if(c->rsa_key)
return true;
logger(LOG_ERR, "No public key for %s specified!", c->name);
return false;
}
static bool read_rsa_private_key(void) {
FILE *fp;
char *fname, *key, *pubkey;
struct stat s;
if(get_config_string(lookup_config(config_tree, "PrivateKey"), &key)) {
if(!get_config_string(lookup_config(config_tree, "PublicKey"), &pubkey)) {
logger(LOG_ERR, "PrivateKey used but no PublicKey found!");
return false;
}
myself->connection->rsa_key = RSA_new();
// RSA_blinding_on(myself->connection->rsa_key, NULL);
BN_hex2bn(&myself->connection->rsa_key->d, key);
BN_hex2bn(&myself->connection->rsa_key->n, pubkey);
BN_hex2bn(&myself->connection->rsa_key->e, "FFFF");
free(key);
free(pubkey);
return true;
}
if(!get_config_string(lookup_config(config_tree, "PrivateKeyFile"), &fname))
xasprintf(&fname, "%s/rsa_key.priv", confbase);
fp = fopen(fname, "r");
if(!fp) {
logger(LOG_ERR, "Error reading RSA private key file `%s': %s",
fname, strerror(errno));
free(fname);
return false;
}
#if !defined(HAVE_MINGW) && !defined(HAVE_CYGWIN)
if(fstat(fileno(fp), &s)) {
logger(LOG_ERR, "Could not stat RSA private key file `%s': %s'",
fname, strerror(errno));
free(fname);
return false;
}
if(s.st_mode & ~0100700)
logger(LOG_WARNING, "Warning: insecure file permissions for RSA private key file `%s'!", fname);
#endif
myself->connection->rsa_key = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL);
fclose(fp);
if(!myself->connection->rsa_key) {
logger(LOG_ERR, "Reading RSA private key file `%s' failed: %s",
fname, strerror(errno));
free(fname);
return false;
}
free(fname);
return true;
}
/*
Read Subnets from all host config files
*/
void load_all_subnets(void) {
DIR *dir;
struct dirent *ent;
char *dname;
char *fname;
avl_tree_t *config_tree;
config_t *cfg;
subnet_t *s, *s2;
node_t *n;
bool result;
xasprintf(&dname, "%s/hosts", confbase);
dir = opendir(dname);
if(!dir) {
logger(LOG_ERR, "Could not open %s: %s", dname, strerror(errno));
free(dname);
return;
}
while((ent = readdir(dir))) {
if(!check_id(ent->d_name))
continue;
n = lookup_node(ent->d_name);
#ifdef _DIRENT_HAVE_D_TYPE
//if(ent->d_type != DT_REG)
// continue;
#endif
xasprintf(&fname, "%s/hosts/%s", confbase, ent->d_name);
init_configuration(&config_tree);
result = read_config_file(config_tree, fname);
free(fname);
if(!result)
continue;
if(!n) {
n = new_node();
n->name = xstrdup(ent->d_name);
node_add(n);
}
for(cfg = lookup_config(config_tree, "Subnet"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
if(!get_config_subnet(cfg, &s))
continue;
if((s2 = lookup_subnet(n, s))) {
s2->expires = -1;
} else {
subnet_add(n, s);
}
}
exit_configuration(&config_tree);
}
closedir(dir);
}
/*
Configure node_t myself and set up the local sockets (listen only)
*/
static bool setup_myself(void) {
config_t *cfg;
subnet_t *subnet;
char *name, *hostname, *mode, *afname, *cipher, *digest, *type;
char *fname = NULL;
char *address = NULL;
char *envp[5];
struct addrinfo *ai, *aip, hint = {0};
bool choice;
int i, err;
int replaywin_int;
myself = new_node();
myself->connection = new_connection();
myself->hostname = xstrdup("MYSELF");
myself->connection->hostname = xstrdup("MYSELF");
myself->connection->options = 0;
myself->connection->protocol_version = PROT_CURRENT;
if(!get_config_string(lookup_config(config_tree, "Name"), &name)) { /* Not acceptable */
logger(LOG_ERR, "Name for tinc daemon required!");
return false;
}
if(!check_id(name)) {
logger(LOG_ERR, "Invalid name for myself!");
free(name);
return false;
}
myself->name = name;
myself->connection->name = xstrdup(name);
xasprintf(&fname, "%s/hosts/%s", confbase, name);
read_config_options(config_tree, name);
read_config_file(config_tree, fname);
free(fname);
if(!read_rsa_private_key())
return false;
if(!get_config_string(lookup_config(config_tree, "Port"), &myport))
myport = xstrdup("655");
if(!atoi(myport)) {
struct addrinfo *ai = str2addrinfo("localhost", myport, SOCK_DGRAM);
sockaddr_t sa;
if(!ai || !ai->ai_addr)
return false;
free(myport);
memcpy(&sa, ai->ai_addr, ai->ai_addrlen);
sockaddr2str(&sa, NULL, &myport);
}
/* Read in all the subnets specified in the host configuration file */
cfg = lookup_config(config_tree, "Subnet");
while(cfg) {
if(!get_config_subnet(cfg, &subnet))
return false;
subnet_add(myself, subnet);
cfg = lookup_config_next(config_tree, cfg);
}
/* Check some options */
if(get_config_bool(lookup_config(config_tree, "IndirectData"), &choice) && choice)
myself->options |= OPTION_INDIRECT;
if(get_config_bool(lookup_config(config_tree, "TCPOnly"), &choice) && choice)
myself->options |= OPTION_TCPONLY;
if(myself->options & OPTION_TCPONLY)
myself->options |= OPTION_INDIRECT;
get_config_bool(lookup_config(config_tree, "DirectOnly"), &directonly);
get_config_bool(lookup_config(config_tree, "StrictSubnets"), &strictsubnets);
get_config_bool(lookup_config(config_tree, "TunnelServer"), &tunnelserver);
get_config_bool(lookup_config(config_tree, "LocalDiscovery"), &localdiscovery);
strictsubnets |= tunnelserver;
if(get_config_string(lookup_config(config_tree, "Mode"), &mode)) {
if(!strcasecmp(mode, "router"))
routing_mode = RMODE_ROUTER;
else if(!strcasecmp(mode, "switch"))
routing_mode = RMODE_SWITCH;
else if(!strcasecmp(mode, "hub"))
routing_mode = RMODE_HUB;
else {
logger(LOG_ERR, "Invalid routing mode!");
return false;
}
free(mode);
}
if(get_config_string(lookup_config(config_tree, "Forwarding"), &mode)) {
if(!strcasecmp(mode, "off"))
forwarding_mode = FMODE_OFF;
else if(!strcasecmp(mode, "internal"))
forwarding_mode = FMODE_INTERNAL;
else if(!strcasecmp(mode, "kernel"))
forwarding_mode = FMODE_KERNEL;
else {
logger(LOG_ERR, "Invalid forwarding mode!");
return false;
}
free(mode);
}
choice = true;
get_config_bool(lookup_config(config_tree, "PMTUDiscovery"), &choice);
if(choice)
myself->options |= OPTION_PMTU_DISCOVERY;
choice = true;
get_config_bool(lookup_config(config_tree, "ClampMSS"), &choice);
if(choice)
myself->options |= OPTION_CLAMP_MSS;
get_config_bool(lookup_config(config_tree, "PriorityInheritance"), &priorityinheritance);
get_config_bool(lookup_config(config_tree, "DecrementTTL"), &decrement_ttl);
get_config_bool(lookup_config(config_tree, "Broadcast"), &broadcast);
#if !defined(SOL_IP) || !defined(IP_TOS)
if(priorityinheritance)
logger(LOG_WARNING, "%s not supported on this platform", "PriorityInheritance");
#endif
if(!get_config_int(lookup_config(config_tree, "MACExpire"), &macexpire))
macexpire = 600;
if(get_config_int(lookup_config(config_tree, "MaxTimeout"), &maxtimeout)) {
if(maxtimeout <= 0) {
logger(LOG_ERR, "Bogus maximum timeout!");
return false;
}
} else
maxtimeout = 900;
if(get_config_int(lookup_config(config_tree, "UDPRcvBuf"), &udp_rcvbuf)) {
if(udp_rcvbuf <= 0) {
logger(LOG_ERR, "UDPRcvBuf cannot be negative!");
return false;
}
}
if(get_config_int(lookup_config(config_tree, "UDPSndBuf"), &udp_sndbuf)) {
if(udp_sndbuf <= 0) {
logger(LOG_ERR, "UDPSndBuf cannot be negative!");
return false;
}
}
if(get_config_int(lookup_config(config_tree, "ReplayWindow"), &replaywin_int)) {
if(replaywin_int < 0) {
logger(LOG_ERR, "ReplayWindow cannot be negative!");
return false;
}
replaywin = (unsigned)replaywin_int;
}
if(get_config_string(lookup_config(config_tree, "AddressFamily"), &afname)) {
if(!strcasecmp(afname, "IPv4"))
addressfamily = AF_INET;
else if(!strcasecmp(afname, "IPv6"))
addressfamily = AF_INET6;
else if(!strcasecmp(afname, "any"))
addressfamily = AF_UNSPEC;
else {
logger(LOG_ERR, "Invalid address family!");
return false;
}
free(afname);
}
get_config_bool(lookup_config(config_tree, "Hostnames"), &hostnames);
/* Generate packet encryption key */
if(get_config_string
(lookup_config(config_tree, "Cipher"), &cipher)) {
if(!strcasecmp(cipher, "none")) {
myself->incipher = NULL;
} else {
myself->incipher = EVP_get_cipherbyname(cipher);
if(!myself->incipher) {
logger(LOG_ERR, "Unrecognized cipher type!");
return false;
}
}
} else
myself->incipher = EVP_bf_cbc();
if(myself->incipher)
myself->inkeylength = myself->incipher->key_len + myself->incipher->iv_len;
else
myself->inkeylength = 1;
myself->connection->outcipher = EVP_bf_ofb();
if(!get_config_int(lookup_config(config_tree, "KeyExpire"), &keylifetime))
keylifetime = 3600;
keyexpires = now + keylifetime;
/* Check if we want to use message authentication codes... */
if(get_config_string(lookup_config(config_tree, "Digest"), &digest)) {
if(!strcasecmp(digest, "none")) {
myself->indigest = NULL;
} else {
myself->indigest = EVP_get_digestbyname(digest);
if(!myself->indigest) {
logger(LOG_ERR, "Unrecognized digest type!");
return false;
}
}
} else
myself->indigest = EVP_sha1();
myself->connection->outdigest = EVP_sha1();
if(get_config_int(lookup_config(config_tree, "MACLength"), &myself->inmaclength)) {
if(myself->indigest) {
if(myself->inmaclength > myself->indigest->md_size) {
logger(LOG_ERR, "MAC length exceeds size of digest!");
return false;
} else if(myself->inmaclength < 0) {
logger(LOG_ERR, "Bogus MAC length!");
return false;
}
}
} else
myself->inmaclength = 4;
myself->connection->outmaclength = 0;
/* Compression */
if(get_config_int(lookup_config(config_tree, "Compression"), &myself->incompression)) {
if(myself->incompression < 0 || myself->incompression > 11) {
logger(LOG_ERR, "Bogus compression level!");
return false;
}
} else
myself->incompression = 0;
myself->connection->outcompression = 0;
/* Done */
myself->nexthop = myself;
myself->via = myself;
myself->status.reachable = true;
node_add(myself);
graph();
if(strictsubnets)
load_all_subnets();
/* Open device */
devops = os_devops;
if(get_config_string(lookup_config(config_tree, "DeviceType"), &type)) {
if(!strcasecmp(type, "dummy"))
devops = dummy_devops;
else if(!strcasecmp(type, "raw_socket"))
devops = raw_socket_devops;
#ifdef ENABLE_UML
else if(!strcasecmp(type, "uml"))
devops = uml_devops;
#endif
#ifdef ENABLE_VDE
else if(!strcasecmp(type, "vde"))
devops = vde_devops;
#endif
}
if(!devops.setup())
return false;
/* Run tinc-up script to further initialize the tap interface */
xasprintf(&envp[0], "NETNAME=%s", netname ? : "");
xasprintf(&envp[1], "DEVICE=%s", device ? : "");
xasprintf(&envp[2], "INTERFACE=%s", iface ? : "");
xasprintf(&envp[3], "NAME=%s", myself->name);
envp[4] = NULL;
execute_script("tinc-up", envp);
for(i = 0; i < 5; i++)
free(envp[i]);
/* Run subnet-up scripts for our own subnets */
subnet_update(myself, NULL, true);
/* Open sockets */
listen_sockets = 0;
cfg = lookup_config(config_tree, "BindToAddress");
do {
get_config_string(cfg, &address);
if(cfg)
cfg = lookup_config_next(config_tree, cfg);
hint.ai_family = addressfamily;
hint.ai_socktype = SOCK_STREAM;
hint.ai_protocol = IPPROTO_TCP;
hint.ai_flags = AI_PASSIVE;
err = getaddrinfo(address, myport, &hint, &ai);
free(address);
if(err || !ai) {
logger(LOG_ERR, "System call `%s' failed: %s", "getaddrinfo",
gai_strerror(err));
return false;
}
for(aip = ai; aip; aip = aip->ai_next) {
if(listen_sockets >= MAXSOCKETS) {
logger(LOG_ERR, "Too many listening sockets");
return false;
}
listen_socket[listen_sockets].tcp =
setup_listen_socket((sockaddr_t *) aip->ai_addr);
if(listen_socket[listen_sockets].tcp < 0)
continue;
listen_socket[listen_sockets].udp =
setup_vpn_in_socket((sockaddr_t *) aip->ai_addr);
if(listen_socket[listen_sockets].udp < 0)
continue;
ifdebug(CONNECTIONS) {
hostname = sockaddr2hostname((sockaddr_t *) aip->ai_addr);
logger(LOG_NOTICE, "Listening on %s", hostname);
free(hostname);
}
memcpy(&listen_socket[listen_sockets].sa, aip->ai_addr, aip->ai_addrlen);
listen_sockets++;
}
freeaddrinfo(ai);
} while(cfg);
if(listen_sockets)
logger(LOG_NOTICE, "Ready");
else {
logger(LOG_ERR, "Unable to create any listening socket!");
return false;
}
return true;
}
/*
initialize network
*/
bool setup_network(void) {
now = time(NULL);
init_events();
init_connections();
init_subnets();
init_nodes();
init_edges();
init_requests();
if(get_config_int(lookup_config(config_tree, "PingInterval"), &pinginterval)) {
if(pinginterval < 1) {
pinginterval = 86400;
}
} else
pinginterval = 60;
if(!get_config_int(lookup_config(config_tree, "PingTimeout"), &pingtimeout))
pingtimeout = 5;
if(pingtimeout < 1 || pingtimeout > pinginterval)
pingtimeout = pinginterval;
if(!get_config_int(lookup_config(config_tree, "MaxOutputBufferSize"), &maxoutbufsize))
maxoutbufsize = 10 * MTU;
if(!setup_myself())
return false;
return true;
}
/*
close all open network connections
*/
void close_network_connections(void) {
avl_node_t *node, *next;
connection_t *c;
char *envp[5];
int i;
for(node = connection_tree->head; node; node = next) {
next = node->next;
c = node->data;
c->outgoing = NULL;
terminate_connection(c, false);
}
for(list_node_t *node = outgoing_list->head; node; node = node->next) {
outgoing_t *outgoing = node->data;
if(outgoing->event)
event_del(outgoing->event);
}
list_delete_list(outgoing_list);
if(myself && myself->connection) {
subnet_update(myself, NULL, false);
terminate_connection(myself->connection, false);
free_connection(myself->connection);
}
for(i = 0; i < listen_sockets; i++) {
close(listen_socket[i].tcp);
close(listen_socket[i].udp);
}
xasprintf(&envp[0], "NETNAME=%s", netname ? : "");
xasprintf(&envp[1], "DEVICE=%s", device ? : "");
xasprintf(&envp[2], "INTERFACE=%s", iface ? : "");
xasprintf(&envp[3], "NAME=%s", myself->name);
envp[4] = NULL;
exit_requests();
exit_edges();
exit_subnets();
exit_nodes();
exit_connections();
exit_events();
execute_script("tinc-down", envp);
if(myport) free(myport);
for(i = 0; i < 4; i++)
free(envp[i]);
devops.close();
return;
}
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