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n2n/tools/n2n-route.c
Hamish Coleman 3bf584c580 Add tweaks to support windows XP
2023-08-03 21:40:31 +01:00

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/**
* (C) 2007-22 - 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 <errno.h> // for errno
#include <getopt.h> // for getopt_long, optind, optarg
#include <signal.h> // for signal, SIGINT, SIGPIPE, SIGTERM, SIG_IGN
#include <stdbool.h>
#include <stdint.h> // for uint8_t, uint16_t, uint32_t
#include <stdio.h> // for snprintf, printf, sscanf
#include <stdlib.h> // for calloc, free, atoi, EXIT_FAILURE, exit
#include <string.h> // for memset, NULL, memcmp, strchr, strcmp
#include <sys/time.h> // for timeval
#include <time.h> // for time, time_t
#include <unistd.h> // for getpid, STDIN_FILENO, _exit, geteuid
#include "json.h" // for _jsonpair, json_object_t, _jsonvalue
#include "n2n.h" // for inaddrtoa, traceEvent, TRACE_WARNING
#include "random_numbers.h" // for n2n_rand, n2n_seed, n2n_srand
#include "uthash.h" // for UT_hash_handle, HASH_ADD, HASH_DEL
#ifdef __linux__
#include <linux/netlink.h> // for nlmsghdr, NLMSG_OK, NETLINK_ROUTE, NLM...
#include <linux/rtnetlink.h> // for RTA_DATA, rtmsg, RTA_GATEWAY, RTA_NEXT
#endif
#ifdef _WIN32
#include <winsock.h>
#include <ws2tcpip.h>
#else
#include <arpa/inet.h> // for inet_pton
#include <net/if.h> // for if_indextoname
#include <net/route.h> // for rtentry, RTF_GATEWAY, RTF_UP
#include <netinet/in.h> // for in_addr, sockaddr_in, htonl, htons, ntohl
#include <sys/ioctl.h> // for ioctl, SIOCADDRT, SIOCDELRT
#include <sys/select.h> // for select, FD_ISSET, FD_SET, FD_ZERO, fd_set
#include <sys/socket.h> // for send, socket, AF_INET, recv, connect
#endif
#if defined (__linux__) || defined(_WIN64) /* currently, Linux and Windows only */
/* Technically, this could be supported on some 32-bit windows.
* The assumption here is that a version of Windows new enough to
* support the features needed is probably running with 64-bit.
*
* The alternative is that people trying to run old games are probably on
* Windows XP and are probably 32-bit.
*/
#define WITH_ADDRESS 1
#define CORRECT_TAG 2
#define SOCKET_TIMEOUT 2
#define GATEWAY_INTERVAL 5
#define INFO_INTERVAL 5
#define REFRESH_INTERVAL 10
#define PURGE_INTERVAL 30
#define REMOVE_ROUTE_AGE 75
#define LOWER_HALF "0.0.0.0"
#define UPPER_HALF "128.0.0.0"
#define MASK_HALF "128.0.0.0" /* <ip address>/1 */
#define HOST_MASK "255.255.255.255" /* <ip address>/32 */
#define ROUTE_ADD 0
#define ROUTE_DEL 1
#define NO_DETECT 0
#define AUTO_DETECT 1
// REVISIT: may become obsolete
#ifdef _WIN32
#ifndef STDIN_FILENO
#define STDIN_FILENO _fileno(stdin)
#endif
#endif
typedef struct n2n_route {
struct in_addr net_addr; /* network address to be routed, also key for hash table*/
struct in_addr net_mask; /* network address mask */
struct in_addr gateway; /* gateway address */
uint8_t purgeable; /* unpurgeable user-supplied or new default route */
time_t last_seen; /* last seen at management port output */
UT_hash_handle hh; /* makes this structure hashable */
} n2n_route_t;
typedef struct n2n_route_conf {
struct in_addr gateway_vpn; /* vpn gateway address */
struct in_addr gateway_org; /* original default gateway used for peer/supernode traffic */
uint8_t gateway_detect; /* have the gateway automatically detected */
char* password; /* pointer to management port password */
uint16_t port; /* management port */
n2n_route_t *routes; /* list of routes */
} n2n_route_conf_t;
static bool keep_running = true; /* for main loop, handled by signals */
// -------------------------------------------------------------------------------------------------------
// PLATFORM-DEPENDANT CODE
int is_privileged (void) {
#if defined(__linux__)
// taken from https://stackoverflow.com/questions/4159910/check-if-user-is-root-in-c
uid_t euid = geteuid();
return euid == 0;
#elif defined(_WIN32)
// taken from https://stackoverflow.com/a/10553065
int result;
DWORD rc;
wchar_t user_name[256];
USER_INFO_1 *info;
DWORD size = sizeof(user_name);
GetUserNameW(user_name, &size);
rc = NetUserGetInfo(NULL, user_name, 1, (unsigned char**)&info);
if (rc) {
return 0;
}
result = (info->usri1_priv == USER_PRIV_ADMIN);
NetApiBufferFree(info);
return result;
#endif
}
// -------------------------------------------------------------------------------------------------------
// PLATFORM-DEPENDANT CODE
void set_term_handler(const void *handler) {
#if defined(__linux__)
signal(SIGPIPE, SIG_IGN);
signal(SIGTERM, handler);
signal(SIGINT, handler);
#elif defined(_WIN32)
SetConsoleCtrlHandler(handler, TRUE);
#endif
}
#ifndef _WIN32
static void term_handler (int sig) {
#else
BOOL WINAPI term_handler (DWORD sig) {
#endif
static int called = 0;
if(called) {
traceEvent(TRACE_NORMAL, "ok, leaving now");
_exit(0);
} else {
traceEvent(TRACE_NORMAL, "shutting down...");
called = 1;
}
keep_running = false;
#ifdef _WIN32
return TRUE;
#endif
}
// -------------------------------------------------------------------------------------------------------
// PLATFORM-DEPENDANT CODE
#define RTLINK_BUFFER_SIZE 8192
int find_default_gateway (struct in_addr *gateway_addr, struct in_addr *exclude) {
#if defined(__linux__)
// taken from https://gist.github.com/javiermon/6272065
// with modifications
// originally licensed under GPLV2, Apache, and/or MIT
int ret = 0;
int received_bytes = 0, msg_len = 0, route_attribute_len = 0;
SOCKET sock = -1;
int msgseq = 0;
struct nlmsghdr *nlh, *nlmsg;
struct rtmsg *route_entry;
struct rtattr *route_attribute; /* this contains route attributes (route type) */
ipstr_t gateway_address;
devstr_t interface;
char msgbuf[RTLINK_BUFFER_SIZE], buffer[RTLINK_BUFFER_SIZE];
char *ptr = buffer;
struct timeval tv;
if((sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE)) < 0) {
traceEvent(TRACE_WARNING, "error from socket() while determining gateway");
// return immediately
return EXIT_FAILURE;
}
memset(msgbuf, 0, sizeof(msgbuf));
memset(buffer, 0, sizeof(buffer));
memset(gateway_address, 0, sizeof(gateway_address));
memset(interface, 0, sizeof(interface));
// point the header and the msg structure pointers into the buffer
nlmsg = (struct nlmsghdr*)msgbuf;
// fill in the nlmsg header
nlmsg->nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
nlmsg->nlmsg_type = RTM_GETROUTE; /* get the routes from kernel routing table */
nlmsg->nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST; /* the message is a request for dump */
nlmsg->nlmsg_seq = msgseq++; /* sequence of the message packet */
nlmsg->nlmsg_pid = getpid(); /* PID of process sending the request */
// 1 sec timeout to avoid stall
tv.tv_sec = 1;
setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, (struct timeval *)&tv, sizeof(struct timeval));
// send msg
if (send(sock, nlmsg, nlmsg->nlmsg_len, 0) < 0) {
traceEvent(TRACE_WARNING, "error from send() while determining gateway");
ret = EXIT_FAILURE;
goto find_default_gateway_end;
}
// receive response
do {
received_bytes = recv(sock, ptr, sizeof(buffer) - msg_len, 0);
if(received_bytes < 0) {
traceEvent(TRACE_WARNING, "error from recv() while determining gateway");
ret = EXIT_FAILURE;
goto find_default_gateway_end;
}
nlh = (struct nlmsghdr *) ptr;
// check if the header is valid
if((NLMSG_OK(nlmsg, received_bytes) == 0) ||
(nlmsg->nlmsg_type == NLMSG_ERROR)) {
traceEvent(TRACE_WARNING, "error in received packet while determining gateway");
ret = EXIT_FAILURE;
goto find_default_gateway_end;
}
// if we received all data break
if(nlh->nlmsg_type == NLMSG_DONE) {
break;
} else {
ptr += received_bytes;
msg_len += received_bytes;
}
// break if its not a multi part message
if((nlmsg->nlmsg_flags & NLM_F_MULTI) == 0)
break;
} while((nlmsg->nlmsg_seq != msgseq) || (nlmsg->nlmsg_pid != getpid()));
// parse response
for ( ; NLMSG_OK(nlh, received_bytes); nlh = NLMSG_NEXT(nlh, received_bytes)) {
// get the route data
route_entry = (struct rtmsg *) NLMSG_DATA(nlh);
// we are just interested in main routing table
if (route_entry->rtm_table != RT_TABLE_MAIN)
continue;
route_attribute = (struct rtattr*)RTM_RTA(route_entry);
route_attribute_len = RTM_PAYLOAD(nlh);
gateway_address[0] = '\0';
interface[0] = '\0';
// loop through all attributes
for( ; RTA_OK(route_attribute, route_attribute_len);
route_attribute = RTA_NEXT(route_attribute, route_attribute_len)) {
switch(route_attribute->rta_type) {
case RTA_OIF:
// for informational purposes only
if_indextoname(*(int*)RTA_DATA(route_attribute), interface);
break;
case RTA_GATEWAY:
inaddrtoa(gateway_address, *(struct in_addr*)RTA_DATA(route_attribute));
break;
default:
break;
}
}
if((*gateway_address) && (*interface)) {
// REVISIT: inet_ntop followed by inet_pton... maybe not too elegant
if(inet_pton(AF_INET, gateway_address, gateway_addr)) {
// do not use the one to be excluded
if(!memcmp(gateway_addr, exclude, sizeof(*gateway_addr)))
continue;
traceEvent(TRACE_DEBUG, "assuming default gateway %s on interface %s",
gateway_address, interface);
break;
}
}
}
find_default_gateway_end:
closesocket(sock);
return ret;
#elif defined(_WIN32)
// taken from (and modified)
// https://docs.microsoft.com/en-us/windows/win32/api/iphlpapi/nf-iphlpapi-createipforwardentry
PMIB_IPFORWARDTABLE pIpForwardTable = NULL;
DWORD dwSize = 0;
BOOL bOrder = FALSE;
DWORD dwStatus = 0;
unsigned int i;
ipstr_t gateway_address;
// find out how big our buffer needs to be
dwStatus = GetIpForwardTable(pIpForwardTable, &dwSize, bOrder);
if(dwStatus == ERROR_INSUFFICIENT_BUFFER) {
// allocate the memory for the table
if(!(pIpForwardTable = (PMIB_IPFORWARDTABLE)malloc(dwSize))) {
traceEvent(TRACE_DEBUG, "malloc failed, out of memory\n");
return EXIT_FAILURE;
}
// now get the table
dwStatus = GetIpForwardTable(pIpForwardTable, &dwSize, bOrder);
}
if (dwStatus != ERROR_SUCCESS) {
traceEvent(TRACE_DEBUG, "getIpForwardTable failed\n");
if(pIpForwardTable)
free(pIpForwardTable);
return EXIT_FAILURE;
}
dwStatus = EXIT_FAILURE;
// search for the row in the table we want. The default gateway has a destination of 0.0.0.0
for(i = 0; i < pIpForwardTable->dwNumEntries; i++) {
if(pIpForwardTable->table[i].dwForwardDest == 0) {
// we have found a default route
// do not use if the gateway is the one to be excluded
if(pIpForwardTable->table[i].dwForwardNextHop == exclude->S_un.S_addr)
continue;
dwStatus = 0;
gateway_addr->S_un.S_addr = pIpForwardTable->table[i].dwForwardNextHop;
traceEvent(TRACE_DEBUG, "assuming default gateway %s",
inaddrtoa(gateway_address, *gateway_addr));
break;
}
}
if(pIpForwardTable) {
free(pIpForwardTable);
}
return dwStatus;
#endif
}
// -------------------------------------------------------------------------------------------------------
// PLATFORM-DEPENDANT CODE
#ifdef _WIN32
DWORD get_interface_index (struct in_addr addr) {
// taken from (and modified)
// https://docs.microsoft.com/en-us/windows/win32/api/iphlpapi/nf-iphlpapi-createipforwardentry
PMIB_IPFORWARDTABLE pIpForwardTable = NULL;
DWORD dwSize = 0;
BOOL bOrder = FALSE;
DWORD dwStatus = 0;
DWORD mask_addr = 0;
DWORD max_idx = 0;
uint8_t bitlen, max_bitlen = 0;
unsigned int i;
ipstr_t gateway_address;
// find out how big our buffer needs to be
dwStatus = GetIpForwardTable(pIpForwardTable, &dwSize, bOrder);
if(dwStatus == ERROR_INSUFFICIENT_BUFFER) {
// allocate the memory for the table
if(!(pIpForwardTable = (PMIB_IPFORWARDTABLE)malloc(dwSize))) {
traceEvent(TRACE_DEBUG, "malloc failed, out of memory\n");
return EXIT_FAILURE;
}
// now get the table
dwStatus = GetIpForwardTable(pIpForwardTable, &dwSize, bOrder);
}
if (dwStatus != ERROR_SUCCESS) {
traceEvent(TRACE_DEBUG, "getIpForwardTable failed\n");
if(pIpForwardTable)
free(pIpForwardTable);
return 0;
}
// search for the row in the table we want. The default gateway has a destination of 0.0.0.0
for(i = 0; i < pIpForwardTable->dwNumEntries; i++) {
mask_addr = pIpForwardTable->table[i].dwForwardMask;
// if same subnet ...
if((mask_addr & addr.S_un.S_addr) == (mask_addr & pIpForwardTable->table[i].dwForwardDest)) {
mask_addr = ntohl(mask_addr);
for(bitlen = 0; (int)mask_addr < 0; mask_addr <<= 1)
bitlen++;
if(bitlen > max_bitlen) {
max_bitlen = bitlen;
max_idx = pIpForwardTable->table[i].dwForwardIfIndex;
}
}
}
traceEvent(TRACE_DEBUG, "found interface index %u for gateway %s",
max_idx, inaddrtoa(gateway_address, addr));
if(pIpForwardTable) {
free(pIpForwardTable);
}
return max_idx;
}
#endif
// -------------------------------------------------------------------------------------------------------
// PLATFORM-DEPENDANT CODE
/* adds (verb == ROUTE_ADD) or deletes (verb == ROUTE_DEL) a route */
void handle_route (n2n_route_t* in_route, int verb) {
#if defined(__linux__)
struct sockaddr_in *addr_tmp;
struct rtentry route;
SOCKET sock;
struct sockaddr_in *dst, *mask, *gateway;
ipstr_t dst_ip_str, gateway_ip_str;
in_addr_t mask_addr;
int bitlen = 0;
// prepare rtentry-typed route entry
memset(&route, 0, sizeof(route));
addr_tmp = (struct sockaddr_in*)&route.rt_dst;
addr_tmp->sin_family = AF_INET;
addr_tmp->sin_addr.s_addr = in_route->net_addr.s_addr;
addr_tmp = (struct sockaddr_in*)&route.rt_genmask;
addr_tmp->sin_family = AF_INET;
addr_tmp->sin_addr.s_addr = in_route->net_mask.s_addr;
addr_tmp = (struct sockaddr_in*)&route.rt_gateway;
addr_tmp->sin_family = AF_INET;
addr_tmp->sin_addr.s_addr = in_route->gateway.s_addr;
route.rt_flags = RTF_UP | RTF_GATEWAY;
route.rt_metric = 0;
// open a socket
sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
// prepare route data for eventual text output
dst = (struct sockaddr_in*)&route.rt_dst;
mask = (struct sockaddr_in*)&route.rt_genmask;
mask_addr = ntohl(mask->sin_addr.s_addr);
for(bitlen = 0; (int)mask_addr < 0; mask_addr <<= 1)
bitlen++;
gateway = (struct sockaddr_in*)&route.rt_gateway;
// try to set route through ioctl
if(ioctl(sock, verb == ROUTE_ADD ? SIOCADDRT : SIOCDELRT, &route) < 0) {
traceEvent(TRACE_WARNING, "error '%s' while %s route to %s/%u via %s",
strerror(errno),
!verb ? "adding" : "deleting",
inaddrtoa(dst_ip_str, dst->sin_addr),
bitlen,
inaddrtoa(gateway_ip_str, gateway->sin_addr));
} else {
traceEvent(TRACE_INFO, "%s route to %s/%u via %s",
!verb ? "added" : "deleted",
inaddrtoa(dst_ip_str, dst->sin_addr),
bitlen,
inaddrtoa(gateway_ip_str, gateway->sin_addr));
}
closesocket(sock);
#elif defined(_WIN32)
// REVISIT: use 'CreateIpForwardEntry()' and 'DeleteIpForwardEntry()' [iphlpapi.h]
char c_net_addr[32];
char c_gateway[32];
char c_interface[32];
char c_verb[32];
uint32_t mask;
uint8_t bitlen;
DWORD if_idx;
char cmd[256];
// assemble route command components
_snprintf(c_net_addr, sizeof(c_net_addr), inet_ntoa(in_route->net_addr));
_snprintf(c_gateway, sizeof(c_gateway), inet_ntoa(in_route->gateway));
mask = ntohl(in_route->net_mask.S_un.S_addr);
for(bitlen = 0; (int)mask < 0; mask <<= 1)
bitlen++;
if_idx = get_interface_index(in_route->gateway);
_snprintf(c_interface, sizeof(c_interface), "if %u", if_idx);
_snprintf(c_verb, sizeof(c_verb), (verb == ROUTE_ADD) ? "add" : "delete");
_snprintf(cmd, sizeof(cmd), "route %s %s/%d %s %s > nul", c_verb, c_net_addr, bitlen, c_gateway, c_interface);
traceEvent(TRACE_INFO, "ROUTE CMD = '%s'\n", cmd);
// issue the route command
system(cmd);
#endif
}
// -------------------------------------------------------------------------------------------------------
void fill_route (n2n_route_t* route, struct in_addr net_addr, struct in_addr net_mask, struct in_addr gateway) {
route->net_addr = net_addr;
route->net_mask = net_mask;
route->gateway = gateway;
}
// applies inet_pton on input string and returns address struct-in_addr-typed address
struct in_addr inet_address (char* in) {
struct in_addr out;
if(inet_pton(AF_INET, in, &out) <= 0) {
out.s_addr = INADDR_NONE;
}
return out;
}
int inet_address_valid (struct in_addr in) {
if(in.s_addr == INADDR_NONE)
return 0;
else
return 1;
}
int same_subnet (struct in_addr addr0, struct in_addr addr1, struct in_addr subnet) {
return (addr0.s_addr & subnet.s_addr) == (addr1.s_addr & subnet.s_addr);
}
// -------------------------------------------------------------------------------------------------------
// PLATFORM-DEPENDANT CODE
SOCKET connect_to_management_port (n2n_route_conf_t *rrr) {
SOCKET ret;
struct sockaddr_in sock_addr;
#ifdef _WIN32
// Windows requires a call to WSAStartup() before it can work with sockets
WORD wVersionRequested;
WSADATA wsaData;
int err;
// Use the MAKEWORD(lowbyte, highbyte) macro declared in Windef.h
wVersionRequested = MAKEWORD(2, 2);
err = WSAStartup(wVersionRequested, &wsaData);
if (err != 0) {
// tell the user that we could not find a usable Winsock DLL
traceEvent(TRACE_ERROR, "WSAStartup failed with error: %d\n", err);
return -1;
}
#endif
ret = socket (PF_INET, SOCK_DGRAM, 0);
if((int)ret < 0)
return -1;
sock_addr.sin_family = AF_INET;
sock_addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
sock_addr.sin_port = htons(rrr->port);
if(0 != connect(ret, (struct sockaddr *)&sock_addr, sizeof(sock_addr)))
return -1;
return ret;
}
// -------------------------------------------------------------------------------------------------------
int get_addr_from_json (struct in_addr *addr, json_object_t *json, char *key, int tag, int flags) {
int i;
char *colon = NULL;
if(NULL == json)
return 0;
for(i = 0; i < json->count; i++) {
if(json->pairs[i].type == JSON_STRING) {
if(!strcmp(json->pairs[i].key, key)) {
// cut off port from IP address
if((colon = strchr(json->pairs[i].value->string_value, ':'))) {
*colon = '\0';
}
*addr = inet_address(json->pairs[i].value->string_value);
flags |= WITH_ADDRESS;
}
if(!strcmp(json->pairs[i].key, "_tag" )) {
if(atoi(json->pairs[i].value->string_value) == tag) {
flags |= CORRECT_TAG;
}
}
} else if(json->pairs[i].type == JSON_OBJECT) {
flags |= get_addr_from_json(addr, json, key, tag, flags);
}
}
return flags;
}
// -------------------------------------------------------------------------------------------------------
// PLATFORM-DEPENDANT CODE
#ifndef _WIN32
// taken from https://web.archive.org/web/20170407122137/http://cc.byexamples.com/2007/04/08/non-blocking-user-input-in-loop-without-ncurses/
int _kbhit () {
struct timeval tv;
fd_set fds;
tv.tv_sec = 0;
tv.tv_usec = 0;
FD_ZERO(&fds);
FD_SET(STDIN_FILENO, &fds); //STDIN_FILENO is 0
select(STDIN_FILENO+1, &fds, NULL, NULL, &tv);
return FD_ISSET(STDIN_FILENO, &fds);
}
#else
// A dummy definition to avoid compile errors on windows
int _kbhit () {
return 0;
}
#endif
// -------------------------------------------------------------------------------------------------------
static void help (int level) {
if(level == 0) return; /* no help required */
printf(" n2n-route [-t <manangement_port>] [-p <management_port_password>] [-v] [-V]"
"\n [-g <default gateway>] [-n <network address>/bitlen[:gateway]]"
"\n <vpn gateway>"
"\n"
"\n This tool sets new routes for all the traffic to be routed via the"
"\n <vpn gateway> and polls the management port of a local n2n edge for"
"\n it can add routes to supernodes and peers via the original default"
"\n gateway. Adapt port (default: %d) and password (default: '%s')"
"\n to match your edge's configuration."
"\n\n If no <default gateway> provided, the tool will try to auto-detect."
"\n\n To only route some traffic through vpn, inidicate the networks to be"
"\n routed with '-n' option and use as many as required."
"\n\n Verbosity can be increased or decreased with -v or -V , repeat as"
"\n as needed."
"\n\n Run with sufficient rights to let the tool add and delete routes."
"\n\n",
N2N_EDGE_MGMT_PORT, N2N_MGMT_PASSWORD);
exit(0);
}
static int set_option (n2n_route_conf_t *rrr, int optkey, char *optargument) {
switch(optkey) {
case 't': /* management port */ {
uint16_t port = atoi(optargument);
if(port) {
rrr->port = port;
} else {
traceEvent(TRACE_WARNING, "invalid management port provided with '-t'");
}
break;
}
case 'p': /* management port password string */ {
rrr->password = optargument;
break;
}
case 'g': /* user-provided original default route */ {
rrr->gateway_org = inet_address(optargument);
if(inet_address_valid(rrr->gateway_org)) {
rrr->gateway_detect = NO_DETECT;
} else {
traceEvent(TRACE_WARNING, "invalid original default gateway provided with '-g'");
}
break;
}
case 'n': /* user-provided network to be routed */ {
char cidr_net[64], bitlen, gateway[64];
n2n_route_t *route;
struct in_addr mask;
int ret;
gateway[0] = '\0'; // optional parameter
ret = sscanf(optargument, "%63[^/]/%hhd:%63s", cidr_net, &bitlen, gateway);
if((ret < 2) || (ret > 3)) {
traceEvent(TRACE_WARNING, "bad cidr network format '%s'", optargument);
return 1;
}
if((bitlen < 0) || (bitlen > 32)) {
traceEvent(TRACE_WARNING, "bad prefix '%d' in '%s'", bitlen, optargument);
return 1;
}
if(!inet_address_valid(inet_address(cidr_net))) {
traceEvent(TRACE_WARNING, "bad network '%s' in '%s'", cidr_net, optargument);
return 1;
}
if(gateway[0]) {
if(!inet_address_valid(inet_address(gateway))) {
traceEvent(TRACE_WARNING, "bad gateway '%s' in '%s'", gateway, optargument);
return 1;
}
}
traceEvent(TRACE_NORMAL, "routing %s/%d via %s", cidr_net, bitlen, gateway[0] ? gateway : "vpn gateway");
route = calloc(1, sizeof(*route));
if(route) {
mask.s_addr = htonl(bitlen2mask(bitlen));
// gateway might be unknown at this point, will be rectified later
fill_route(route, inet_address(cidr_net), mask, inet_address(gateway));
HASH_ADD(hh, rrr->routes, net_addr, sizeof(route->net_addr), route);
// will be added to system table later
}
break;
}
case 'v': /* more verbose */ {
setTraceLevel(getTraceLevel() + 1);
break;
}
case 'V': /* less verbose */ {
setTraceLevel(getTraceLevel() - 1);
break;
}
default: /* unknown option */ {
return 1; /* for help */
}
}
return 0;
}
// -------------------------------------------------------------------------------------------------------
int main (int argc, char* argv[]) {
n2n_route_conf_t rrr;
uint8_t c;
char *p;
SOCKET sock;
size_t msg_len;
char udp_buf[N2N_PKT_BUF_SIZE];
fd_set socket_mask;
struct timeval wait_time;
time_t now = 0;
time_t last_gateway_check = 0;
time_t last_info_req = 0;
time_t last_read_req = 0;
time_t last_purge = 0;
json_object_t *json;
int ret;
int tag_info, tag_route_ip;
struct in_addr addr, edge, edge_netmask, addr_tmp;
ipstr_t ip_str;
n2n_route_t *route, *tmp_route;
// version
print_n2n_version();
// handle signals to properly end the tool
set_term_handler(term_handler);
// init data structure
rrr.gateway_vpn = inet_address("");
rrr.gateway_org = inet_address("");
rrr.gateway_detect = AUTO_DETECT;
rrr.password = N2N_MGMT_PASSWORD;
rrr.port = N2N_EDGE_MGMT_PORT;
rrr.routes = NULL;
setTraceLevel(2); /* NORMAL, should already be default */
n2n_srand(n2n_seed());
// get command line options and eventually overwrite initialized conf
while((c = getopt_long(argc, argv, "t:p:g:n:vV", NULL, NULL)) != '?') {
if(c == 255) break;
help(set_option(&rrr, c, optarg));
}
// get mandatory vpn gateway from command line and ...
if(argv[optind]) {
rrr.gateway_vpn = inet_address(argv[optind]);
}
// ... output help if invalid
help(!inet_address_valid(rrr.gateway_vpn));
traceEvent(TRACE_NORMAL, "using vpn gateway %s", inaddrtoa(ip_str, rrr.gateway_vpn));
// verify conf and react with output to conf-related changes
if(rrr.gateway_detect == NO_DETECT) {
traceEvent(TRACE_NORMAL, "using default gateway %s", inaddrtoa(ip_str, rrr.gateway_org));
}
// if nothing else set, set new default route
if(!rrr.routes) {
route = calloc(1, sizeof(n2n_route_t));
if(route) {
traceEvent(TRACE_NORMAL, "routing 0.0.0.1/1");
fill_route(route, inet_address(LOWER_HALF), inet_address(MASK_HALF), rrr.gateway_vpn);
HASH_ADD(hh, rrr.routes, net_addr, sizeof(route->net_addr), route);
}
route = calloc(1, sizeof(n2n_route_t));
if(route) {
traceEvent(TRACE_NORMAL, "routing 128.0.0.1/1");
fill_route(route, inet_address(UPPER_HALF), inet_address(MASK_HALF), rrr.gateway_vpn);
HASH_ADD(hh, rrr.routes, net_addr, sizeof(route->net_addr), route);
}
} else {
traceEvent(TRACE_WARNING, "only user-supplied networks will be routed, not the complete traffic");
}
// set gateway for all so far present routes if '-n'-provided do not have it yet,
// make them UNPURGEABLE and add them to system table
HASH_ITER(hh, rrr.routes, route, tmp_route) {
if(!inet_address_valid(route->gateway)) {
route->gateway = rrr.gateway_vpn;
}
route->purgeable = false;
handle_route(route, ROUTE_ADD);
}
// additional checks
// check for sufficient rights for adding/deleting routes
if(!is_privileged()) {
traceEvent(TRACE_WARNING, "did not detect sufficient privileges to exercise route control");
}
// REVISIT: can we check if forwarding is enabled and, if not so, warn the user?
// connect to mamagement port
traceEvent(TRACE_NORMAL, "connecting to edge management port %d", rrr.port);
sock = connect_to_management_port(&rrr);
if(sock == -1) {
traceEvent(TRACE_ERROR, "unable to open socket for management port connection");
goto end_route_tool;
}
// output status
traceEvent(TRACE_NORMAL, "press ENTER to end the program");
reset_main_loop:
wait_time.tv_sec = SOCKET_TIMEOUT;
wait_time.tv_usec = 0;
edge = inet_address("");
edge_netmask = inet_address("");
addr_tmp = inet_address("");
tag_info = 0;
tag_route_ip = 0;
// main loop
// read answer packet by packet which are only accepted if a corresponding request was sent before
// of which we know about by having set the related tag, tag_info or tag_route_ip resp.
// a valid edge ip address indicates that we have seen a valid answer to the info request
while(keep_running && !_kbhit()) {
// current time
now = time(NULL);
// in case of AUTO_DETECT, check for (changed) default gateway from time to time (and initially)
if((rrr.gateway_detect == AUTO_DETECT) && (now > last_gateway_check + GATEWAY_INTERVAL)) {
// determine the original default gateway excluding the VPN gateway from search
find_default_gateway(&addr_tmp, &rrr.gateway_vpn);
if(memcmp(&addr_tmp, &rrr.gateway_org, sizeof(rrr.gateway_org))) {
// store the detected change
rrr.gateway_org = addr_tmp;
// delete all purgeable routes as they are still relying on old original default gateway
HASH_ITER(hh, rrr.routes, route, tmp_route) {
if((route->purgeable == true)) {
handle_route(route, ROUTE_DEL);
HASH_DEL(rrr.routes, route);
free(route);
}
}
// give way for new info and read requests
last_info_req = 0;
last_read_req = 0;
traceEvent(TRACE_NORMAL, "using default gateway %s", inaddrtoa(ip_str, rrr.gateway_org));
}
last_gateway_check = now;
}
// check if we need to send info request again
if(now > last_info_req + INFO_INTERVAL) {
// send info read request
while(!(tag_info = ((uint32_t)n2n_rand()) >> 23));
msg_len = 0;
msg_len += snprintf((char *) (udp_buf + msg_len), (N2N_PKT_BUF_SIZE - msg_len),
"r %u info\n", tag_info);
ret = send(sock, udp_buf, msg_len, 0);
last_info_req = now;
}
// check if we need to send read request again
if(now > last_read_req + REFRESH_INTERVAL) {
// the following requests shall only be sent if we have a valid local edge ip address,
// i.e. a valid answer to the info request
if(inet_address_valid(edge)) {
// REVISIT: send unsubscribe request to management port if required to re-subscribe
// send subscribe request to management port, generate fresh tag
while(!(tag_route_ip = ((uint32_t)n2n_rand()) >> 23)); /* >> 23: tags too long can crash the mgmt */
msg_len = 0;
msg_len += snprintf((char *) (udp_buf + msg_len), (N2N_PKT_BUF_SIZE - msg_len),
"s %u:1:%s peer\n", tag_route_ip, rrr.password);
// REVISIT: something smashes the edge when sending subscritpion request or when edge sends event
// so, the subscription request is not sent yet
// ret = send(sock, udp_buf, msg_len, 0);
// send read requests to management port with same tag
msg_len = 0;
msg_len += snprintf((char *) (udp_buf + msg_len), (N2N_PKT_BUF_SIZE - msg_len),
"r %u edges\n", tag_route_ip);
ret = send(sock, udp_buf, msg_len, 0);
msg_len = 0;
msg_len += snprintf((char *) (udp_buf + msg_len), (N2N_PKT_BUF_SIZE - msg_len),
"r %u supernodes\n", tag_route_ip);
ret = send(sock, udp_buf, msg_len, 0);
last_read_req = now;
}
}
// purge the routes from time to time
if(now > last_purge + PURGE_INTERVAL) {
last_purge = now;
HASH_ITER(hh, rrr.routes, route, tmp_route) {
if((route->purgeable == true) && (now > route->last_seen + REMOVE_ROUTE_AGE)) {
handle_route(route, ROUTE_DEL);
HASH_DEL(rrr.routes, route);
free(route);
}
}
}
// REVISIT: check all routes from rrr.routes for still being in system table from time to time?
// or even apply some rtlink magic to get notified on route changes?
// wait for any answer to info or read request
FD_ZERO(&socket_mask);
FD_SET(sock, &socket_mask);
ret = select(sock + 1, &socket_mask, NULL, NULL, &wait_time);
// refresh current time after having waited
now = time(NULL);
if(ret > 0) {
if(FD_ISSET(sock, &socket_mask)) {
msg_len = recv(sock, udp_buf, sizeof(udp_buf), 0);
if((msg_len > 0) && (msg_len < sizeof(udp_buf))) {
// make sure it is a string and replace all newlines with spaces
udp_buf[msg_len] = '\0';
for (p = udp_buf; (p = strchr(p, '\n')) != NULL; p++) *p = ' ';
traceEvent(TRACE_DEBUG, "received '%s' from management port", udp_buf);
// handle the answer, json needs to be freed later
json = json_parse(udp_buf);
// look for local edge information
if(tag_info) {
// local IP address (for information)
ret = get_addr_from_json(&addr, json, "ip4addr", tag_info, 0);
if(ret == (WITH_ADDRESS | CORRECT_TAG)) {
traceEvent(TRACE_DEBUG, "received information about %s being edge's IP address", inaddrtoa(ip_str, addr));
if(memcmp(&edge, &addr, sizeof(edge))) {
edge = addr;
traceEvent(TRACE_NORMAL, "found %s being edge's IP address", inaddrtoa(ip_str, addr));
}
}
// local netmask
ret = get_addr_from_json(&addr, json, "ip4netmask", tag_info, 0);
if(ret == (WITH_ADDRESS | CORRECT_TAG)) {
traceEvent(TRACE_DEBUG, "received information about %s being edge's IP netmask", inaddrtoa(ip_str, addr));
if(memcmp(&edge_netmask, &addr, sizeof(edge_netmask))) {
edge_netmask = addr;
traceEvent(TRACE_NORMAL, "found %s being edge's IP netmask", inaddrtoa(ip_str, addr));
// check if vpn gateway matches edge information and warn user if not so
if(!same_subnet(edge, rrr.gateway_vpn, edge_netmask)) {
traceEvent(TRACE_WARNING, "vpn gateway and edge do not share the same subnet");
}
}
}
}
// look for edge/supernode ip addresses
if(tag_route_ip) {
ret = get_addr_from_json(&addr, json, "sockaddr", tag_route_ip, 0);
if(ret == (WITH_ADDRESS | CORRECT_TAG)) {
// add to hash list if required
traceEvent(TRACE_DEBUG, "received information about %s to be routed via default gateway", inaddrtoa(ip_str, addr));
HASH_FIND(hh, rrr.routes, &addr, sizeof(route->net_addr), route);
if(!route)
route = calloc(1, sizeof(n2n_route_t));
else
HASH_DEL(rrr.routes, route);
if(route) {
fill_route(route, addr, inet_address(HOST_MASK), rrr.gateway_org);
route->purgeable = true;
if(!(route->last_seen)) {
handle_route(route, ROUTE_ADD);
}
route->last_seen = now;
HASH_ADD(hh, rrr.routes, net_addr, sizeof(route->net_addr), route);
}
}
}
// no need for current json object anymore
json_free(json);
}
} else {
// can this happen? reset the loop
traceEvent(TRACE_ERROR, "loop reset");
goto reset_main_loop;
}
} else if(ret == 0) {
// select() timeout
// action required?
} else {
// select() error
// action required?
}
}
// REVISIT: send unsubscribe request to management port if required
end_route_tool:
// delete all routes
HASH_ITER(hh, rrr.routes, route, tmp_route) {
handle_route(route, ROUTE_DEL);
HASH_DEL(rrr.routes, route);
free(route);
}
// close connection
closesocket(sock);
return 0;
}
#else /* if defined(__linux__) || defined(_WIN64) -- currently, Linux and Windows only */
int main (int argc, char* argv[]) {
traceEvent(TRACE_WARNING, "currently, only Linux and 64-bit Windows are supported");
traceEvent(TRACE_WARNING, "if you want to port to other OS, please find the source code having clearly marked the platform-dependant portions");
return 0;
}
#endif /* if defined (__linux__) || defined(_WIN64) -- currently, Linux and Windows only */
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