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n2n/edge.c
emanuele-f d689691599 n2n.h cleanup
2019-04-14 18:08:51 +02:00

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/**
* (C) 2007-18 - ntop.org and contributors
*
* 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 3 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 see see <http://www.gnu.org/licenses/>
*
*/
#include "n2n.h"
#ifdef WIN32
#include <sys/stat.h>
#endif
#define N2N_NETMASK_STR_SIZE 16 /* dotted decimal 12 numbers + 3 dots */
#define N2N_MACNAMSIZ 18 /* AA:BB:CC:DD:EE:FF + NULL*/
#define N2N_IF_MODE_SIZE 16 /* static | dhcp */
/* *************************************************** */
/** maximum length of command line arguments */
#define MAX_CMDLINE_BUFFER_LENGTH 4096
/** maximum length of a line in the configuration file */
#define MAX_CONFFILE_LINE_LENGTH 1024
/* ***************************************************** */
typedef struct {
int local_port;
int mgmt_port;
char tuntap_dev_name[N2N_IFNAMSIZ];
char ip_mode[N2N_IF_MODE_SIZE];
char ip_addr[N2N_NETMASK_STR_SIZE];
char netmask[N2N_NETMASK_STR_SIZE];
int mtu;
int got_s;
char device_mac[N2N_MACNAMSIZ];
char * encrypt_key;
#ifndef WIN32
uid_t userid;
gid_t groupid;
#endif
} edge_conf_t;
/* ***************************************************** */
/** Find the address and IP mode for the tuntap device.
*
* s is one of these forms:
*
* <host> := <hostname> | A.B.C.D
*
* <host> | static:<host> | dhcp:<host>
*
* If the mode is present (colon required) then fill ip_mode with that value
* otherwise do not change ip_mode. Fill ip_mode with everything after the
* colon if it is present; or s if colon is not present.
*
* ip_add and ip_mode are NULL terminated if modified.
*
* return 0 on success and -1 on error
*/
static int scan_address(char * ip_addr, size_t addr_size,
char * ip_mode, size_t mode_size,
const char * s) {
int retval = -1;
char * p;
if((NULL == s) || (NULL == ip_addr))
{
return -1;
}
memset(ip_addr, 0, addr_size);
p = strpbrk(s, ":");
if(p)
{
/* colon is present */
if(ip_mode)
{
size_t end=0;
memset(ip_mode, 0, mode_size);
end = MIN(p-s, (ssize_t)(mode_size-1)); /* ensure NULL term */
strncpy(ip_mode, s, end);
strncpy(ip_addr, p+1, addr_size-1); /* ensure NULL term */
retval = 0;
}
}
else
{
/* colon is not present */
strncpy(ip_addr, s, addr_size);
}
return retval;
}
/* *************************************************** */
static void help() {
print_n2n_version();
printf("edge <config file> (see edge.conf)\n"
"or\n"
);
printf("edge "
#if defined(N2N_CAN_NAME_IFACE)
"-d <tun device> "
#endif /* #if defined(N2N_CAN_NAME_IFACE) */
"-a [static:|dhcp:]<tun IP address> "
"-c <community> "
"[-k <encrypt key> | -K <key file>]\n"
" "
"[-s <netmask>] "
#ifndef WIN32
"[-u <uid> -g <gid>]"
#endif /* #ifndef WIN32 */
#ifndef WIN32
"[-f]"
#endif /* #ifndef WIN32 */
"[-m <MAC address>] "
"-l <supernode host:port>\n"
" "
"[-p <local port>] [-M <mtu>] "
"[-r] [-E] [-v] [-t <mgmt port>] [-b] [-A] [-h]\n\n");
#ifdef __linux__
printf("-d <tun device> | tun device name\n");
#endif
printf("-a <mode:address> | Set interface address. For DHCP use '-r -a dhcp:0.0.0.0'\n");
printf("-c <community> | n2n community name the edge belongs to.\n");
printf("-k <encrypt key> | Encryption key (ASCII) - also N2N_KEY=<encrypt key>. Not with -K.\n");
printf("-K <key file> | Specify a key schedule file to load. Not with -k.\n");
printf("-s <netmask> | Edge interface netmask in dotted decimal notation (255.255.255.0).\n");
printf("-l <supernode host:port> | Supernode IP:port\n");
printf("-b | Periodically resolve supernode IP\n");
printf(" | (when supernodes are running on dynamic IPs)\n");
printf("-p <local port> | Fixed local UDP port.\n");
#ifndef WIN32
printf("-u <UID> | User ID (numeric) to use when privileges are dropped.\n");
printf("-g <GID> | Group ID (numeric) to use when privileges are dropped.\n");
#endif /* ifndef WIN32 */
#ifndef WIN32
printf("-f | Do not fork and run as a daemon; rather run in foreground.\n");
#endif /* #ifndef WIN32 */
printf("-m <MAC address> | Fix MAC address for the TAP interface (otherwise it may be random)\n"
" | eg. -m 01:02:03:04:05:06\n");
printf("-M <mtu> | Specify n2n MTU of edge interface (default %d).\n", DEFAULT_MTU);
printf("-r | Enable packet forwarding through n2n community.\n");
#ifdef N2N_HAVE_AES
printf("-A | Set AES CBC as the preferred encryption mode.\n");
#endif
printf("-E | Accept multicast MAC addresses (default=drop).\n");
printf("-v | Make more verbose. Repeat as required.\n");
printf("-t <port> | Management UDP Port (for multiple edges on a machine).\n");
printf("\nEnvironment variables:\n");
printf(" N2N_KEY | Encryption key (ASCII). Not with -K or -k.\n");
exit(0);
}
/* *************************************************** */
static int setOption(int optkey, char *optargument, edge_conf_t *ec, n2n_edge_t *eee) {
/* traceEvent(TRACE_NORMAL, "Option %c = %s", optkey, optargument ? optargument : ""); */
switch(optkey) {
case'K':
{
if(ec->encrypt_key) {
traceEvent(TRACE_ERROR, "Error: -K and -k options are mutually exclusive");
exit(1);
} else {
strncpy(eee->keyschedule, optargument, N2N_PATHNAME_MAXLEN-1);
/* strncpy does not add NULL if the source has no NULL. */
eee->keyschedule[N2N_PATHNAME_MAXLEN-1] = 0;
traceEvent(TRACE_NORMAL, "keyfile = '%s'\n", eee->keyschedule);
}
break;
}
case 'a': /* IP address and mode of TUNTAP interface */
{
scan_address(ec->ip_addr, N2N_NETMASK_STR_SIZE,
ec->ip_mode, N2N_IF_MODE_SIZE,
optargument);
break;
}
case 'c': /* community as a string */
{
memset(eee->community_name, 0, N2N_COMMUNITY_SIZE);
strncpy((char *)eee->community_name, optargument, N2N_COMMUNITY_SIZE);
break;
}
case 'E': /* multicast ethernet addresses accepted. */
{
eee->drop_multicast=0;
traceEvent(TRACE_DEBUG, "Enabling ethernet multicast traffic");
break;
}
#ifndef WIN32
case 'u': /* unprivileged uid */
{
ec->userid = atoi(optargument);
break;
}
case 'g': /* unprivileged uid */
{
ec->groupid = atoi(optargument);
break;
}
#endif
#ifndef WIN32
case 'f' : /* do not fork as daemon */
{
eee->daemon=0;
break;
}
#endif /* #ifndef WIN32 */
case 'm' : /* TUNTAP MAC address */
{
strncpy(ec->device_mac,optargument,N2N_MACNAMSIZ);
break;
}
case 'M' : /* TUNTAP MTU */
{
ec->mtu = atoi(optargument);
break;
}
case 'k': /* encrypt key */
{
if(strlen(eee->keyschedule) > 0) {
traceEvent(TRACE_ERROR, "-K and -k options are mutually exclusive");
exit(1);
} else {
traceEvent(TRACE_DEBUG, "encrypt_key = '%s'\n", ec->encrypt_key);
ec->encrypt_key = strdup(optargument);
}
break;
}
case 'r': /* enable packet routing across n2n endpoints */
{
eee->allow_routing = 1;
break;
}
#ifdef N2N_HAVE_AES
case 'A':
{
eee->preferred_aes = 1;
break;
}
#endif
case 'l': /* supernode-list */
if(optargument) {
if(eee->sn_num < N2N_EDGE_NUM_SUPERNODES) {
strncpy((eee->sn_ip_array[eee->sn_num]), optargument, N2N_EDGE_SN_HOST_SIZE);
traceEvent(TRACE_NORMAL, "Adding supernode[%u] = %s", (unsigned int)eee->sn_num, (eee->sn_ip_array[eee->sn_num]));
++eee->sn_num;
} else {
traceEvent(TRACE_WARNING, "Too many supernodes!");
exit(1);
}
break;
}
#if defined(N2N_CAN_NAME_IFACE)
case 'd': /* TUNTAP name */
{
strncpy(ec->tuntap_dev_name, optargument, N2N_IFNAMSIZ);
break;
}
#endif
case 'b':
{
eee->re_resolve_supernode_ip = 1;
break;
}
case 'p':
{
ec->local_port = atoi(optargument);
break;
}
case 't':
{
ec->mgmt_port = atoi(optargument);
break;
}
case 's': /* Subnet Mask */
{
if(0 != ec->got_s) {
traceEvent(TRACE_WARNING, "Multiple subnet masks supplied");
}
strncpy(ec->netmask, optargument, N2N_NETMASK_STR_SIZE);
ec->got_s = 1;
break;
}
case 'h': /* help */
{
help();
break;
}
case 'v': /* verbose */
setTraceLevel(4); /* DEBUG */
break;
default:
{
traceEvent(TRACE_WARNING, "Unknown option -%c: Ignored", (char)optkey);
return(-1);
}
}
return(0);
}
/* *********************************************** */
static const struct option long_options[] = {
{ "community", required_argument, NULL, 'c' },
{ "supernode-list", required_argument, NULL, 'l' },
{ "tun-device", required_argument, NULL, 'd' },
{ "euid", required_argument, NULL, 'u' },
{ "egid", required_argument, NULL, 'g' },
{ "help" , no_argument, NULL, 'h' },
{ "verbose", no_argument, NULL, 'v' },
{ NULL, 0, NULL, 0 }
};
/* *************************************************** */
/* read command line options */
static int loadFromCLI(int argc, char *argv[], edge_conf_t *ec, n2n_edge_t *eee) {
u_char c;
while((c = getopt_long(argc, argv,
"K:k:a:bc:Eu:g:m:M:s:d:l:p:fvhrt:"
#ifdef N2N_HAVE_AES
"A"
#endif
,
long_options, NULL)) != '?') {
if(c == 255) break;
setOption(c, optarg, ec, eee);
}
return 0;
}
/* *************************************************** */
static char *trim(char *s) {
char *end;
while(isspace(s[0]) || (s[0] == '"') || (s[0] == '\'')) s++;
if(s[0] == 0) return s;
end = &s[strlen(s) - 1];
while(end > s
&& (isspace(end[0])|| (end[0] == '"') || (end[0] == '\'')))
end--;
end[1] = 0;
return s;
}
/* *************************************************** */
/* parse the configuration file */
static int loadFromFile(const char *path, edge_conf_t *ec, n2n_edge_t *eee) {
char buffer[4096], *line, *key, *value;
u_int line_len, opt_name_len;
FILE *fd;
const struct option *opt;
fd = fopen(path, "r");
if(fd == NULL) {
traceEvent(TRACE_WARNING, "Config file %s not found", path);
return -1;
}
while((line = fgets(buffer, sizeof(buffer), fd)) != NULL) {
line = trim(line);
value = NULL;
if((line_len = strlen(line)) < 2 || line[0] == '#')
continue;
if(!strncmp(line, "--", 2)) { /* long opt */
key = &line[2], line_len -= 2;
opt = long_options;
while(opt->name != NULL) {
opt_name_len = strlen(opt->name);
if(!strncmp(key, opt->name, opt_name_len)
&& (line_len <= opt_name_len
|| key[opt_name_len] == '\0'
|| key[opt_name_len] == ' '
|| key[opt_name_len] == '=')) {
if(line_len > opt_name_len) key[opt_name_len] = '\0';
if(line_len > opt_name_len + 1) value = trim(&key[opt_name_len + 1]);
// traceEvent(TRACE_NORMAL, "long key: %s value: %s", key, value);
setOption(opt->val, value, ec, eee);
break;
}
opt++;
}
} else if(line[0] == '-') { /* short opt */
key = &line[1], line_len--;
if(line_len > 1) key[1] = '\0';
if(line_len > 2) value = trim(&key[2]);
// traceEvent(TRACE_NORMAL, "key: %c value: %s", key[0], value);
setOption(key[0], value, ec, eee);
} else {
traceEvent(TRACE_WARNING, "Skipping unrecognized line: %s", line);
continue;
}
}
fclose(fd);
return 0;
}
/* ************************************** */
#if defined(DUMMY_ID_00001) /* Disabled waiting for config option to enable it */
static char gratuitous_arp[] = {
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, /* Dest mac */
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* Src mac */
0x08, 0x06, /* ARP */
0x00, 0x01, /* Ethernet */
0x08, 0x00, /* IP */
0x06, /* Hw Size */
0x04, /* Protocol Size */
0x00, 0x01, /* ARP Request */
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* Src mac */
0x00, 0x00, 0x00, 0x00, /* Src IP */
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* Target mac */
0x00, 0x00, 0x00, 0x00 /* Target IP */
};
/* ************************************** */
/** Build a gratuitous ARP packet for a /24 layer 3 (IP) network. */
static int build_gratuitous_arp(char *buffer, uint16_t buffer_len) {
if(buffer_len < sizeof(gratuitous_arp)) return(-1);
memcpy(buffer, gratuitous_arp, sizeof(gratuitous_arp));
memcpy(&buffer[6], device.mac_addr, 6);
memcpy(&buffer[22], device.mac_addr, 6);
memcpy(&buffer[28], &device.ip_addr, 4);
/* REVISIT: BbMaj7 - use a real netmask here. This is valid only by accident
* for /24 IPv4 networks. */
buffer[31] = 0xFF; /* Use a faked broadcast address */
memcpy(&buffer[38], &device.ip_addr, 4);
return(sizeof(gratuitous_arp));
}
/* ************************************** */
/** Called from update_supernode_reg to periodically send gratuitous ARP
* broadcasts. */
static void send_grat_arps(n2n_edge_t * eee,) {
char buffer[48];
size_t len;
traceEvent(TRACE_NORMAL, "Sending gratuitous ARP...");
len = build_gratuitous_arp(buffer, sizeof(buffer));
send_packet2net(eee, buffer, len);
send_packet2net(eee, buffer, len); /* Two is better than one :-) */
}
#endif /* #if defined(DUMMY_ID_00001) */
/* ************************************** */
static void daemonize() {
#ifndef WIN32
int childpid;
traceEvent(TRACE_NORMAL, "Parent process is exiting (this is normal)");
signal(SIGPIPE, SIG_IGN);
signal(SIGHUP, SIG_IGN);
signal(SIGCHLD, SIG_IGN);
signal(SIGQUIT, SIG_IGN);
if((childpid = fork()) < 0)
traceEvent(TRACE_ERROR, "Occurred while daemonizing (errno=%d)",
errno);
else {
if(!childpid) { /* child */
int rc;
//traceEvent(TRACE_NORMAL, "Bye bye: I'm becoming a daemon...");
rc = chdir("/");
if(rc != 0)
traceEvent(TRACE_ERROR, "Error while moving to / directory");
setsid(); /* detach from the terminal */
fclose(stdin);
fclose(stdout);
/* fclose(stderr); */
/*
* clear any inherited file mode creation mask
*/
//umask(0);
/*
* Use line buffered stdout
*/
/* setlinebuf (stdout); */
setvbuf(stdout, (char *)NULL, _IOLBF, 0);
} else /* father */
exit(0);
}
#endif
}
/* *************************************************** */
/** Entry point to program from kernel. */
int main(int argc, char* argv[]) {
int keep_on_running = 1;
int rc;
int i;
n2n_edge_t eee; /* single instance for this program */
edge_conf_t ec;
if(argc == 1)
help();
ec.local_port = 0 /* any port */;
ec.mgmt_port = N2N_EDGE_MGMT_PORT; /* 5644 by default */
snprintf(ec.tuntap_dev_name, sizeof(ec.tuntap_dev_name), "edge0");
snprintf(ec.ip_mode, sizeof(ec.ip_mode), "static");
snprintf(ec.netmask, sizeof(ec.netmask), "255.255.255.0");
ec.ip_addr[0] = '\0';
ec.device_mac[0] = '\0';
ec.mtu = DEFAULT_MTU;
ec.got_s = 0;
ec.encrypt_key = NULL;
#ifndef WIN32
ec.userid = 0; /* root is the only guaranteed ID */
ec.groupid = 0; /* root is the only guaranteed ID */
#endif
if(-1 == edge_init(&eee)) {
traceEvent(TRACE_ERROR, "Failed in edge_init");
exit(1);
}
if(getenv("N2N_KEY")) {
ec.encrypt_key = strdup(getenv("N2N_KEY"));
}
#ifdef WIN32
ec.tuntap_dev_name[0] = '\0';
#endif
memset(&(eee.supernode), 0, sizeof(eee.supernode));
eee.supernode.family = AF_INET;
#ifndef WIN32
if((argc >= 2) && (argv[1][0] != '-')) {
rc = loadFromFile(argv[1], &ec, &eee);
if(argc > 2)
rc = loadFromCLI(argc, argv, &ec, &eee);
} else
#endif
rc = loadFromCLI(argc, argv, &ec, &eee);
if((rc < 0) || (eee.sn_num == 0))
help();
traceEvent(TRACE_NORMAL, "Starting n2n edge %s %s", PACKAGE_VERSION, PACKAGE_BUILDDATE);
for (i=0; i<eee.sn_num; ++i)
traceEvent(TRACE_NORMAL, "supernode %u => %s\n", i, (eee.sn_ip_array[i]));
supernode2addr(&(eee.supernode), eee.sn_ip_array[eee.sn_idx]);
if(!(
#ifdef __linux__
(ec.tuntap_dev_name[0] != 0) &&
#endif
(eee.community_name[0] != 0) &&
(ec.ip_addr[0] != 0)
))
{
help();
}
#ifndef WIN32
if(eee.daemon) {
setUseSyslog(1); /* traceEvent output now goes to syslog. */
daemonize();
}
#endif /* #ifndef WIN32 */
if((NULL == ec.encrypt_key) && (0 == strlen(eee.keyschedule)))
{
traceEvent(TRACE_WARNING, "Encryption is disabled in edge.");
eee.null_transop = 1;
}
#ifndef WIN32
/* If running suid root then we need to setuid before using the force. */
setuid(0);
/* setgid(0); */
#endif
if(0 == strcmp("dhcp", ec.ip_mode)) {
traceEvent(TRACE_NORMAL, "Dynamic IP address assignment enabled.");
eee.dyn_ip_mode = 1;
} else
traceEvent(TRACE_NORMAL, "ip_mode='%s'", ec.ip_mode);
if(tuntap_open(&(eee.device), ec.tuntap_dev_name, ec.ip_mode, ec.ip_addr, ec.netmask, ec.device_mac, ec.mtu) < 0)
return(-1);
#ifndef WIN32
if((ec.userid != 0) || (ec.groupid != 0)) {
traceEvent(TRACE_NORMAL, "Interface up. Dropping privileges to uid=%d, gid=%d",
(signed int)ec.userid, (signed int)ec.groupid);
/* Finished with the need for root privileges. Drop to unprivileged user. */
setreuid(ec.userid, ec.userid);
setregid(ec.groupid, ec.groupid);
}
#endif
if(ec.local_port > 0)
traceEvent(TRACE_NORMAL, "Binding to local port %d", (signed int)ec.local_port);
if(ec.encrypt_key) {
if(edge_init_encryption(&eee, (uint8_t *)ec.encrypt_key, strlen(ec.encrypt_key)) != 0) {
traceEvent(TRACE_ERROR, "Error: encryption setup failed");
return(-1);
}
} else if(strlen(eee.keyschedule) > 0) {
if(edge_init_keyschedule(&eee) < 0) {
traceEvent(TRACE_ERROR, "Error: keyschedule setup failed");
return(-1);
}
}
/* else run in NULL mode */
if(edge_init_sockets(&eee, ec.local_port, ec.mgmt_port) < 0) {
traceEvent(TRACE_ERROR, "Error: socket setup failed");
return(-1);
}
traceEvent(TRACE_NORMAL, "edge started");
return run_edge_loop(&eee, &keep_on_running);
}
/* ************************************** */
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