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mactelnetd.c
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mactelnetd.c
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/*
Mac-Telnet - Connect to RouterOS or mactelnetd devices via MAC address
Copyright (C) 2010, Håkon Nessjøen <haakon.nessjoen@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.
*/
#define _XOPEN_SOURCE 600
#define _BSD_SOURCE
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <endian.h>
#include <time.h>
#include <arpa/inet.h>
#include <net/ethernet.h>
#include <netinet/in.h>
#include <netinet/ether.h>
#include <sys/time.h>
#include <time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <string.h>
#ifdef __linux__
#include <linux/if_ether.h>
#else
#include <sys/time.h>
#endif
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/sysinfo.h>
#include <pwd.h>
#include <utmp.h>
#include <syslog.h>
#include <sys/utsname.h>
#include "md5.h"
#include "protocol.h"
#include "console.h"
#include "interfaces.h"
#include "users.h"
#include "config.h"
#define PROGRAM_NAME "MAC-Telnet Daemon"
#define MAX_INSOCKETS 100
#define MT_INTERFACE_LEN 128
/* Max ~5 pings per second */
#define MT_MAXPPS MT_MNDP_BROADCAST_INTERVAL * 5
static int sockfd;
static int insockfd;
static int mndpsockfd;
static int pings = 0;
struct net_interface interfaces[MAX_INTERFACES];
static int use_raw_socket = 0;
static struct in_addr sourceip;
static struct in_addr destip;
static int sourceport;
static time_t last_mndp_time = 0;
/* Protocol data direction */
unsigned char mt_direction_fromserver = 1;
/* Anti-timeout is every 10 seconds. Give up after 15. */
#define MT_CONNECTION_TIMEOUT 15
/* Connection states */
enum mt_connection_state {
STATE_AUTH,
STATE_CLOSED,
STATE_ACTIVE
};
/** Connection struct */
struct mt_connection {
struct net_interface *interface;
char interface_name[256];
unsigned short seskey;
unsigned int incounter;
unsigned int outcounter;
time_t lastdata;
int terminal_mode;
enum mt_connection_state state;
int ptsfd;
int slavefd;
int pid;
int wait_for_ack;
int have_enckey;
char username[30];
unsigned char trypassword[17];
unsigned char srcip[IPV4_ALEN];
unsigned char srcmac[ETH_ALEN];
unsigned short srcport;
unsigned char dstmac[ETH_ALEN];
unsigned char enckey[16];
unsigned short terminal_width;
unsigned short terminal_height;
char terminal_type[30];
struct mt_connection *next;
};
static void uwtmp_login(struct mt_connection *);
static void uwtmp_logout(struct mt_connection *);
static struct mt_connection *connections_head = NULL;
static void list_add_connection(struct mt_connection *conn) {
struct mt_connection *p;
struct mt_connection *last;
if (connections_head == NULL) {
connections_head = conn;
connections_head->next = NULL;
return;
}
for (p = connections_head; p != NULL; p = p->next) {last = p;}
last->next = conn;
conn->next = NULL;
}
static void list_remove_connection(struct mt_connection *conn) {
struct mt_connection *p;
struct mt_connection *last;
if (connections_head == NULL) {
return;
}
if (conn->state == STATE_ACTIVE && conn->ptsfd > 0) {
close(conn->ptsfd);
}
if (conn->state == STATE_ACTIVE && conn->slavefd > 0) {
close(conn->slavefd);
}
uwtmp_logout(conn);
if (connections_head == conn) {
connections_head = conn->next;
free(conn);
return;
}
for (p = connections_head; p != NULL; p = p->next) {
if (p == conn) {
last->next = p->next;
free(p);
return;
}
last = p;
}
}
static struct mt_connection *list_find_connection(unsigned short seskey, unsigned char *srcmac) {
struct mt_connection *p;
if (connections_head == NULL) {
return NULL;
}
for (p = connections_head; p != NULL; p = p->next) {
if (p->seskey == seskey && memcmp(srcmac, p->srcmac, ETH_ALEN) == 0) {
return p;
}
}
return NULL;
}
static int find_socket(unsigned char *mac) {
int i;
for (i = 0; i < MAX_INTERFACES; ++i) {
if (interfaces[i].in_use && memcmp(mac, interfaces[i].mac_addr, ETH_ALEN) == 0) {
return i;
}
if (!interfaces[i].in_use) {
break;
}
}
return -1;
}
static void setup_sockets() {
int i;
for (i = 0; i < MAX_INTERFACES; ++i) {
int optval = 1;
struct sockaddr_in si_me;
struct ether_addr *mac = (struct ether_addr *)&(interfaces[i].mac_addr);
if (interfaces[i].in_use == 0 || !interfaces[i].has_mac) {
continue;
}
if (!use_raw_socket) {
interfaces[i].socketfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
if (interfaces[i].socketfd < 0) {
continue;
}
if (setsockopt(interfaces[i].socketfd, SOL_SOCKET, SO_BROADCAST, &optval, sizeof (optval))==-1) {
perror("SO_BROADCAST");
continue;
}
setsockopt(interfaces[i].socketfd, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(optval));
/* Initialize receiving socket on the device chosen */
si_me.sin_family = AF_INET;
si_me.sin_port = htons(MT_MACTELNET_PORT);
memcpy(&(si_me.sin_addr.s_addr), interfaces[i].ipv4_addr, IPV4_ALEN);
if (bind(interfaces[i].socketfd, (struct sockaddr *)&si_me, sizeof(si_me))==-1) {
fprintf(stderr, "Error binding to %s:%d, %s\n", inet_ntoa(si_me.sin_addr), sourceport, strerror(errno));
continue;
}
}
syslog(LOG_NOTICE, "Listening on %s for %s\n", interfaces[i].name, ether_ntoa(mac));
}
}
static int send_udp(const struct mt_connection *conn, const struct mt_packet *packet) {
if (use_raw_socket) {
return net_send_udp(sockfd, conn->interface, conn->dstmac, conn->srcmac, &sourceip, sourceport, &destip, conn->srcport, packet->data, packet->size);
} else {
/* Init SendTo struct */
struct sockaddr_in socket_address;
socket_address.sin_family = AF_INET;
socket_address.sin_port = htons(conn->srcport);
socket_address.sin_addr.s_addr = htonl(INADDR_BROADCAST);
return sendto(conn->interface->socketfd, packet->data, packet->size, 0, (struct sockaddr*)&socket_address, sizeof(socket_address));
}
}
static int send_special_udp(struct net_interface *interface, unsigned short port, const struct mt_packet *packet) {
unsigned char dstmac[ETH_ALEN];
if (use_raw_socket) {
memset(dstmac, 0xff, ETH_ALEN);
return net_send_udp(sockfd, interface, interface->mac_addr, dstmac, (const struct in_addr *)&interface->ipv4_addr, port, &destip, port, packet->data, packet->size);
} else {
/* Init SendTo struct */
struct sockaddr_in socket_address;
socket_address.sin_family = AF_INET;
socket_address.sin_port = htons(port);
socket_address.sin_addr.s_addr = htonl(INADDR_BROADCAST);
return sendto(interface->socketfd, packet->data, packet->size, 0, (struct sockaddr*)&socket_address, sizeof(socket_address));
}
}
static void display_motd() {
FILE *fp;
int c;
if ((fp = fopen("/etc/motd", "r"))) {
while ((c = getc(fp)) != EOF) {
putchar(c);
}
fclose(fp);
}
}
static void display_nologin() {
FILE *fp;
int c;
if ((fp = fopen(_PATH_NOLOGIN, "r"))) {
while ((c = getc(fp)) != EOF) {
putchar(c);
}
fclose(fp);
}
}
static void uwtmp_login(struct mt_connection *conn) {
struct utmp utent;
pid_t pid;
pid = getpid();
char *line = ttyname(conn->slavefd);
if (strncmp(line, "/dev/", 5) == 0) {
line += 5;
}
/* Setup utmp struct */
memset((void *) &utent, 0, sizeof(utent));
utent.ut_type = USER_PROCESS;
utent.ut_pid = pid;
strncpy(utent.ut_user, conn->username, sizeof(utent.ut_user));
strncpy(utent.ut_line, line, sizeof(utent.ut_line));
strncpy(utent.ut_id, utent.ut_line + 3, sizeof(utent.ut_id));
strncpy(utent.ut_host, ether_ntoa((const struct ether_addr *)conn->srcmac), sizeof(utent.ut_host));
time((time_t *)&(utent.ut_time));
/* Update utmp and/or wtmp */
setutent();
pututline(&utent);
endutent();
updwtmp(_PATH_WTMP, &utent);
}
static void uwtmp_logout(struct mt_connection *conn) {
if (conn->pid > 0) {
struct utmp *utentp;
struct utmp utent;
setutent();
while ((utentp = getutent()) != NULL) {
if (utentp->ut_pid == conn->pid && utentp->ut_id) {
break;
}
}
if (utentp) {
utent = *utentp;
utent.ut_type = DEAD_PROCESS;
utent.ut_tv.tv_sec = time(NULL);
pututline(&utent);
endutent();
updwtmp(_PATH_WTMP, &utent);
}
}
}
static void abort_connection(struct mt_connection *curconn, struct mt_mactelnet_hdr *pkthdr, char *message) {
struct mt_packet pdata;
init_packet(&pdata, MT_PTYPE_DATA, pkthdr->dstaddr, pkthdr->srcaddr, pkthdr->seskey, curconn->outcounter);
add_control_packet(&pdata, MT_CPTYPE_PLAINDATA, message, strlen(message));
send_udp(curconn, &pdata);
/* Make connection time out; lets the previous message get acked before disconnecting */
curconn->state = STATE_CLOSED;
init_packet(&pdata, MT_PTYPE_END, pkthdr->dstaddr, pkthdr->srcaddr, pkthdr->seskey, curconn->outcounter);
send_udp(curconn, &pdata);
}
static void user_login(struct mt_connection *curconn, struct mt_mactelnet_hdr *pkthdr) {
struct mt_packet pdata;
unsigned char md5sum[17];
char md5data[100];
struct mt_credentials *user;
char *slavename;
/* Reparse user file before each login */
read_userfile();
if ((user = find_user(curconn->username)) != NULL) {
md5_state_t state;
/* Concat string of 0 + password + encryptionkey */
md5data[0] = 0;
strncpy(md5data + 1, user->password, 82);
memcpy(md5data + 1 + strlen(user->password), curconn->enckey, 16);
/* Generate md5 sum of md5data with a leading 0 */
md5_init(&state);
md5_append(&state, (const md5_byte_t *)md5data, strlen(user->password) + 17);
md5_finish(&state, (md5_byte_t *)md5sum + 1);
md5sum[0] = 0;
init_packet(&pdata, MT_PTYPE_DATA, pkthdr->dstaddr, pkthdr->srcaddr, pkthdr->seskey, curconn->outcounter);
curconn->outcounter += add_control_packet(&pdata, MT_CPTYPE_END_AUTH, NULL, 0);
send_udp(curconn, &pdata);
if (curconn->state == STATE_ACTIVE) {
return;
}
}
if (user == NULL || memcmp(md5sum, curconn->trypassword, 17) != 0) {
syslog(LOG_NOTICE, "(%d) Invalid login by %s.", curconn->seskey, curconn->username);
abort_connection(curconn, pkthdr, "Login failed, incorrect username or password\r\n");
/* TODO: should wait some time (not with sleep) before returning, to minimalize brute force attacks */
return;
}
/* User is logged in */
curconn->state = STATE_ACTIVE;
/* Enter terminal mode */
curconn->terminal_mode = 1;
/* Open pts handle */
curconn->ptsfd = posix_openpt(O_RDWR);
if (curconn->ptsfd == -1 || grantpt(curconn->ptsfd) == -1 || unlockpt(curconn->ptsfd) == -1) {
syslog(LOG_ERR, "posix_openpt: %s", strerror(errno));
abort_connection(curconn, pkthdr, "Terminal error\r\n");
return;
}
/* Get file path for our pts */
slavename = ptsname(curconn->ptsfd);
if (slavename != NULL) {
pid_t pid;
struct stat sb;
struct passwd *user = (struct passwd *)getpwnam(curconn->username);
if (user == NULL) {
syslog(LOG_WARNING, "(%d) Login ok, but local user not accessible (%s).", curconn->seskey, curconn->username);
abort_connection(curconn, pkthdr, "Local user not accessible\r\n");
return;
}
/* Change the owner of the slave pts */
chown(slavename, user->pw_uid, user->pw_gid);
curconn->slavefd = open(slavename, O_RDWR);
if (curconn->slavefd == -1) {
syslog(LOG_ERR, "Error opening %s: %s", slavename, strerror(errno));
abort_connection(curconn, pkthdr, "Error opening terminal\r\n");
list_remove_connection(curconn);
return;
}
if ((pid = fork()) == 0) {
int i;
/* Add login information to utmp/wtmp */
uwtmp_login(curconn);
syslog(LOG_INFO, "(%d) User %s logged in.", curconn->seskey, curconn->username);
/* Initialize terminal environment */
setenv("USER", user->pw_name, 1);
setenv("HOME", user->pw_dir, 1);
setenv("SHELL", user->pw_shell, 1);
setenv("TERM", curconn->terminal_type, 1);
close(sockfd);
close(insockfd);
for (i = 0; i < MAX_INTERFACES; ++i) {
if (interfaces[i].in_use && interfaces[i].socketfd > 0) {
close(interfaces[i].socketfd);
}
if (!interfaces[i].in_use) {
break;
}
}
setsid();
/* Don't let shell process inherit slavefd */
fcntl (curconn->slavefd, F_SETFD, FD_CLOEXEC);
close(curconn->ptsfd);
/* Redirect STDIN/STDIO/STDERR */
close(0);
dup(curconn->slavefd);
close(1);
dup(curconn->slavefd);
close(2);
dup(curconn->slavefd);
/* Set controlling terminal */
ioctl(0, TIOCSCTTY, 1);
tcsetpgrp(0, getpid());
/* Set user id/group id */
if ((setgid(user->pw_gid) != 0) || (setuid(user->pw_uid) != 0)) {
syslog(LOG_ERR, "(%d) Could not log in %s (%d:%d): setuid/setgid: %s", curconn->seskey, curconn->username, user->pw_uid, user->pw_gid, strerror(errno));
abort_connection(curconn, pkthdr, "Internal error\r\n");
exit(0);
}
/* Abort login if /etc/nologin exists */
if (stat(_PATH_NOLOGIN, &sb) == 0 && getuid() != 0) {
syslog(LOG_NOTICE, "(%d) User %s disconnected with " _PATH_NOLOGIN " message.", curconn->seskey, curconn->username);
display_nologin();
curconn->state = STATE_CLOSED;
init_packet(&pdata, MT_PTYPE_END, pkthdr->dstaddr, pkthdr->srcaddr, pkthdr->seskey, curconn->outcounter);
send_udp(curconn, &pdata);
exit(0);
}
/* Display MOTD */
display_motd();
chdir(user->pw_dir);
/* Spawn shell */
/* TODO: Maybe use "login -f USER" instead? renders motd and executes shell correctly for system */
execl(user->pw_shell, "-", (char *) 0);
exit(0); // just to be sure.
}
close(curconn->slavefd);
curconn->pid = pid;
set_terminal_size(curconn->ptsfd, curconn->terminal_width, curconn->terminal_height);
}
}
static void handle_data_packet(struct mt_connection *curconn, struct mt_mactelnet_hdr *pkthdr, int data_len) {
struct mt_mactelnet_control_hdr cpkt;
struct mt_packet pdata;
unsigned char *data = pkthdr->data;
int got_user_packet = 0;
int got_pass_packet = 0;
int got_width_packet = 0;
int got_height_packet = 0;
int success;
/* Parse first control packet */
success = parse_control_packet(data, data_len - MT_HEADER_LEN, &cpkt);
while (success) {
if (cpkt.cptype == MT_CPTYPE_BEGINAUTH) {
int plen,i;
if (!curconn->have_enckey) {
for (i = 0; i < 16; ++i) {
curconn->enckey[i] = rand() % 256;
}
curconn->have_enckey = 1;
memset(curconn->trypassword, 0, sizeof(curconn->trypassword));
}
init_packet(&pdata, MT_PTYPE_DATA, pkthdr->dstaddr, pkthdr->srcaddr, pkthdr->seskey, curconn->outcounter);
plen = add_control_packet(&pdata, MT_CPTYPE_ENCRYPTIONKEY, (curconn->enckey), 16);
curconn->outcounter += plen;
send_udp(curconn, &pdata);
} else if (cpkt.cptype == MT_CPTYPE_USERNAME) {
memcpy(curconn->username, cpkt.data, cpkt.length > 29 ? 29 : cpkt.length);
curconn->username[cpkt.length > 29 ? 29 : cpkt.length] = 0;
got_user_packet = 1;
} else if (cpkt.cptype == MT_CPTYPE_TERM_WIDTH) {
unsigned short width;
memcpy(&width, cpkt.data, 2);
curconn->terminal_width = le16toh(width);
got_width_packet = 1;
} else if (cpkt.cptype == MT_CPTYPE_TERM_HEIGHT) {
unsigned short height;
memcpy(&height, cpkt.data, 2);
curconn->terminal_height = le16toh(height);
got_height_packet = 1;
} else if (cpkt.cptype == MT_CPTYPE_TERM_TYPE) {
memcpy(curconn->terminal_type, cpkt.data, cpkt.length > 29 ? 29 : cpkt.length);
curconn->terminal_type[cpkt.length > 29 ? 29 : cpkt.length] = 0;
} else if (cpkt.cptype == MT_CPTYPE_PASSWORD) {
memcpy(curconn->trypassword, cpkt.data, 17);
got_pass_packet = 1;
} else if (cpkt.cptype == MT_CPTYPE_PLAINDATA) {
/* relay data from client to shell */
if (curconn->state == STATE_ACTIVE && curconn->ptsfd != -1) {
write(curconn->ptsfd, cpkt.data, cpkt.length);
}
} else {
syslog(LOG_WARNING, "(%d) Unhandeled control packet type: %d", curconn->seskey, cpkt.cptype);
}
/* Parse next control packet */
success = parse_control_packet(NULL, 0, &cpkt);
}
if (got_user_packet && got_pass_packet) {
user_login(curconn, pkthdr);
}
if (curconn->state == STATE_ACTIVE && (got_width_packet || got_height_packet)) {
set_terminal_size(curconn->ptsfd, curconn->terminal_width, curconn->terminal_height);
}
}
static void handle_packet(unsigned char *data, int data_len, const struct sockaddr_in *address) {
struct mt_mactelnet_hdr pkthdr;
struct mt_connection *curconn = NULL;
struct mt_packet pdata;
int interface_index;
parse_packet(data, &pkthdr);
/* Drop packets not belonging to us */
if ((interface_index = find_socket(pkthdr.dstaddr)) < 0) {
return;
}
switch (pkthdr.ptype) {
case MT_PTYPE_PING:
if (pings++ > MT_MAXPPS) {
break;
}
init_pongpacket(&pdata, (unsigned char *)&(pkthdr.dstaddr), (unsigned char *)&(pkthdr.srcaddr));
add_packetdata(&pdata, pkthdr.data - 4, data_len - (MT_HEADER_LEN - 4));
{
if (index >= 0) {
send_special_udp(&interfaces[interface_index], MT_MACTELNET_PORT, &pdata);
}
}
break;
case MT_PTYPE_SESSIONSTART:
syslog(LOG_DEBUG, "(%d) New connection from %s.", pkthdr.seskey, ether_ntoa((struct ether_addr*)&(pkthdr.srcaddr)));
curconn = calloc(1, sizeof(struct mt_connection));
curconn->seskey = pkthdr.seskey;
curconn->lastdata = time(NULL);
curconn->state = STATE_AUTH;
curconn->interface = &interfaces[interface_index];
strncpy(curconn->interface_name, interfaces[interface_index].name, 254);
curconn->interface_name[255] = '\0';
memcpy(curconn->srcmac, pkthdr.srcaddr, ETH_ALEN);
memcpy(curconn->srcip, &(address->sin_addr), IPV4_ALEN);
curconn->srcport = htons(address->sin_port);
memcpy(curconn->dstmac, pkthdr.dstaddr, ETH_ALEN);
list_add_connection(curconn);
init_packet(&pdata, MT_PTYPE_ACK, pkthdr.dstaddr, pkthdr.srcaddr, pkthdr.seskey, pkthdr.counter);
send_udp(curconn, &pdata);
break;
case MT_PTYPE_END:
curconn = list_find_connection(pkthdr.seskey, (unsigned char *)&(pkthdr.srcaddr));
if (curconn == NULL) {
break;
}
if (curconn->state != STATE_CLOSED) {
init_packet(&pdata, MT_PTYPE_END, pkthdr.dstaddr, pkthdr.srcaddr, pkthdr.seskey, pkthdr.counter);
send_udp(curconn, &pdata);
}
syslog(LOG_DEBUG, "(%d) Connection closed.", curconn->seskey);
list_remove_connection(curconn);
return;
case MT_PTYPE_ACK:
curconn = list_find_connection(pkthdr.seskey, (unsigned char *)&(pkthdr.srcaddr));
if (curconn == NULL) {
break;
}
if (pkthdr.counter <= curconn->outcounter) {
curconn->wait_for_ack = 0;
}
if (time(0) - curconn->lastdata > 9) {
// Answer to anti-timeout packet
init_packet(&pdata, MT_PTYPE_ACK, pkthdr.dstaddr, pkthdr.srcaddr, pkthdr.seskey, pkthdr.counter);
send_udp(curconn, &pdata);
}
curconn->lastdata = time(NULL);
return;
case MT_PTYPE_DATA:
curconn = list_find_connection(pkthdr.seskey, (unsigned char *)&(pkthdr.srcaddr));
if (curconn == NULL) {
break;
}
curconn->lastdata = time(NULL);
/* ack the data packet */
init_packet(&pdata, MT_PTYPE_ACK, pkthdr.dstaddr, pkthdr.srcaddr, pkthdr.seskey, pkthdr.counter + (data_len - MT_HEADER_LEN));
send_udp(curconn, &pdata);
/* Accept first packet, and all packets greater than incounter, and if counter has
wrapped around. */
if (curconn->incounter == 0 || pkthdr.counter > curconn->incounter || (curconn->incounter - pkthdr.counter) > 16777216) {
curconn->incounter = pkthdr.counter;
} else {
/* Ignore double or old packets */
return;
}
handle_data_packet(curconn, &pkthdr, data_len);
break;
default:
if (curconn) {
syslog(LOG_WARNING, "(%d) Unhandeled packet type: %d", curconn->seskey, pkthdr.ptype);
init_packet(&pdata, MT_PTYPE_ACK, pkthdr.dstaddr, pkthdr.srcaddr, pkthdr.seskey, pkthdr.counter);
send_udp(curconn, &pdata);
}
}
if (0 && curconn != NULL) {
printf("Packet, incounter %d, outcounter %d\n", curconn->incounter, curconn->outcounter);
}
}
static void daemonize() {
int pid,fd;
pid = fork();
/* Error? */
if (pid < 0) {
exit(1);
}
/* Parent exit */
if (pid > 0) {
exit(0);
}
setsid();
close(0);
close(1);
close(2);
fd = open("/dev/null",O_RDWR);
dup(fd);
dup(fd);
}
static void print_version() {
fprintf(stderr, PROGRAM_NAME " " PROGRAM_VERSION "\n");
}
void mndp_broadcast() {
struct mt_packet pdata;
struct utsname s_uname;
int i;
unsigned int uptime;
#ifdef __linux__
struct sysinfo s_sysinfo;
if (sysinfo(&s_sysinfo) != 0) {
return;
}
/* Seems like ping uptime is transmitted as little endian? */
uptime = htole32(s_sysinfo.uptime);
#else
struct timespec ts;
if (clock_gettime(CLOCK_UPTIME, &ts) != -1) {
uptime = htole32(((unsigned int)ts.tv_sec));
}
#endif
if (uname(&s_uname) != 0) {
return;
}
for (i = 0; i < MAX_INTERFACES; ++i) {
struct net_interface *interface = &interfaces[i];
struct mt_mndp_hdr *header = (struct mt_mndp_hdr *)&(pdata.data);
if (interfaces[i].has_mac == 0) {
continue;
}
if (interfaces[i].in_use == 0) {
break;
}
mndp_init_packet(&pdata, 0, 1);
mndp_add_attribute(&pdata, MT_MNDPTYPE_ADDRESS, interface->mac_addr, ETH_ALEN);
mndp_add_attribute(&pdata, MT_MNDPTYPE_IDENTITY, s_uname.nodename, strlen(s_uname.nodename));
mndp_add_attribute(&pdata, MT_MNDPTYPE_VERSION, s_uname.release, strlen(s_uname.release));
mndp_add_attribute(&pdata, MT_MNDPTYPE_PLATFORM, PLATFORM_NAME, strlen(PLATFORM_NAME));
mndp_add_attribute(&pdata, MT_MNDPTYPE_HARDWARE, s_uname.machine, strlen(s_uname.machine));
mndp_add_attribute(&pdata, MT_MNDPTYPE_TIMESTAMP, &uptime, 4);
header->cksum = in_cksum((unsigned short *)&(pdata.data), pdata.size);
send_special_udp(interface, MT_MNDP_PORT, &pdata);
}
}
void sigterm_handler() {
struct mt_connection *p;
struct mt_packet pdata;
char message[] = "\r\n\r\nDaemon shutting down.\r\n";
syslog(LOG_NOTICE, "Daemon shutting down");
for (p = connections_head; p != NULL; p = p->next) {
if (p->state == STATE_ACTIVE) {
init_packet(&pdata, MT_PTYPE_DATA, p->interface->mac_addr, p->srcmac, p->seskey, p->outcounter);
add_control_packet(&pdata, MT_CPTYPE_PLAINDATA, message, strlen(message));
send_udp(p, &pdata);
init_packet(&pdata, MT_PTYPE_END, p->interface->mac_addr, p->srcmac, p->seskey, p->outcounter);
send_udp(p, &pdata);
}
}
/* Doesn't hurt to tidy up */
close(sockfd);
close(insockfd);
if (!use_raw_socket) {
int i;
for (i = 0; i < MAX_INTERFACES; ++i) {
if (interfaces[i].in_use && interfaces[i].socketfd > 0)
close(interfaces[i].socketfd);
}
}
closelog();
exit(0);
}
void sighup_handler() {
int i;
struct mt_connection *p;
syslog(LOG_NOTICE, "SIGHUP: Reloading interfaces");
if (!use_raw_socket) {
for (i = 0; i < MAX_INTERFACES; ++i) {
close(interfaces[i].socketfd);
}
}
bzero(interfaces, sizeof(interfaces));
if (net_get_interfaces(interfaces, MAX_INTERFACES) <= 0) {
syslog(LOG_ERR, "No devices found! Exiting.\n");
exit(1);
}
setup_sockets();
/* Reassign outgoing interfaces to connections again, since they may have changed */
for (p = connections_head; p != NULL; p = p->next) {
if (p->interface_name != NULL) {
struct net_interface *interface = net_get_interface_ptr(interfaces, MAX_INTERFACES, p->interface_name, 0);
if (interface != NULL) {
p->interface = interface;
} else {
struct mt_connection tmp;
syslog(LOG_NOTICE, "(%d) Connection closed because interface %s is gone.", p->seskey, p->interface_name);
tmp.next = p->next;
list_remove_connection(p);
p = &tmp;
}
}
}
}
/*
* TODO: Rewrite main() when all sub-functionality is tested
*/
int main (int argc, char **argv) {
int result,i;
struct sockaddr_in si_me;
struct sockaddr_in si_me_mndp;
struct timeval timeout;
struct mt_packet pdata;
fd_set read_fds;
int c,optval = 1;
int print_help = 0;
int foreground = 0;
int interface_count = 0;
while ((c = getopt(argc, argv, "fnvh?")) != -1) {
switch (c) {
case 'f':
foreground = 1;
break;
case 'n':
use_raw_socket = 1;
break;
case 'v':
print_version();
exit(0);
break;
case 'h':
case '?':
print_help = 1;
break;
}
}
if (print_help) {
print_version();
fprintf(stderr, "Usage: %s [-f|-n|-h]\n", argv[0]);
if (print_help) {
fprintf(stderr, "\nParameters:\n");
fprintf(stderr, " -f Run process in foreground.\n");
fprintf(stderr, " -n Do not use broadcast packets. Just a tad less insecure.\n");
fprintf(stderr, " -h This help.\n");
fprintf(stderr, "\n");
}
return 1;
}
if (geteuid() != 0) {
fprintf(stderr, "You need to have root privileges to use %s.\n", argv[0]);
return 1;
}
/* Try to read user file */
read_userfile();
/* Seed randomizer */
srand(time(NULL));
if (use_raw_socket) {
/* Transmit raw packets with this socket */
sockfd = net_init_raw_socket();
}
/* Receive regular udp packets with this socket */
insockfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
if (insockfd < 0) {
perror("insockfd");
return 1;
}
/* Set source port */
sourceport = MT_MACTELNET_PORT;
/* Listen address*/
inet_pton(AF_INET, (char *)"0.0.0.0", &sourceip);
/* Set up global info about the connection */
inet_pton(AF_INET, (char *)"255.255.255.255", &destip);
/* Initialize receiving socket on the device chosen */
memset((char *) &si_me, 0, sizeof(si_me));
si_me.sin_family = AF_INET;
si_me.sin_port = htons(sourceport);
memcpy(&(si_me.sin_addr), &sourceip, IPV4_ALEN);
setsockopt(insockfd, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof (optval));
/* Bind to udp port */
if (bind(insockfd, (struct sockaddr *)&si_me, sizeof(si_me))==-1) {
fprintf(stderr, "Error binding to %s:%d, %s\n", inet_ntoa(si_me.sin_addr), sourceport, strerror(errno));
return 1;
}
/* TODO: Move socket initialization out of main() */
/* Receive mndp udp packets with this socket */
mndpsockfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
if (mndpsockfd < 0) {
perror("mndpsockfd");
return 1;
}
memset((char *)&si_me_mndp, 0, sizeof(si_me_mndp));
si_me_mndp.sin_family = AF_INET;
si_me_mndp.sin_port = htons(MT_MNDP_PORT);
memcpy(&(si_me_mndp.sin_addr), &sourceip, IPV4_ALEN);
setsockopt(mndpsockfd, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof (optval));
/* Bind to udp port */
if (bind(mndpsockfd, (struct sockaddr *)&si_me_mndp, sizeof(si_me_mndp))==-1) {
fprintf(stderr, "MNDP: Error binding to %s:%d, %s\n", inet_ntoa(si_me_mndp.sin_addr), MT_MNDP_PORT, strerror(errno));
}
openlog("mactelnetd", LOG_PID, LOG_DAEMON);
syslog(LOG_NOTICE, "Bound to %s:%d", inet_ntoa(si_me.sin_addr), sourceport);
/* Enumerate available interfaces */
net_get_interfaces(interfaces, MAX_INTERFACES);
setup_sockets();
if (!foreground) {
daemonize();