int main(int argc, char **argv)
{
char pppLocal[16]; /* local IP to pass to pppd */
char pppRemote[16]; /* remote IP address to pass to pppd */
struct sockaddr_in addr; /* client address */
socklen_t addrlen;
int arg = 1;
int flags;
struct in_addr inetaddrs[2];
char *pppaddrs[2] = { pppLocal, pppRemote };
gargc = argc;
gargv = argv;
/* fail if argument count invalid */
if (argc < 7) {
fprintf(stderr, "pptpctrl: insufficient arguments, see man pptpctrl\n");
exit(2);
}
/* open a connection to the syslog daemon */
openlog("pptpd", LOG_PID, PPTP_FACILITY);
/* autoreap if supported */
signal(SIGCHLD, SIG_IGN);
/* note: update pptpctrl.8 if the argument list format is changed */
GETARG_INT(pptpctrl_debug);
GETARG_INT(noipparam);
GETARG_VALUE(pppdxfig);
GETARG_VALUE(speed);
GETARG_VALUE(pppLocal);
GETARG_VALUE(pppRemote);
if (arg < argc) GETARG_INT(unique_call_id);
if (arg < argc) GETARG_STRING(ppp_binary);
if (arg < argc) GETARG_INT(pptp_logwtmp);
if (pptpctrl_debug) {
if (*pppLocal)
syslog(LOG_DEBUG, "CTRL: local address = %s", pppLocal);
if (*pppRemote)
syslog(LOG_DEBUG, "CTRL: remote address = %s", pppRemote);
if (*speed)
syslog(LOG_DEBUG, "CTRL: pppd speed = %s", speed);
if (*pppdxfig)
syslog(LOG_DEBUG, "CTRL: pppd options file = %s", pppdxfig);
}
addrlen = sizeof(addr);
if (getsockname(clientSocket, (struct sockaddr *) &addr, &addrlen) != 0) {
syslog(LOG_ERR, "CTRL: getsockname() failed");
syslog_perror("getsockname");
close(clientSocket);
bail(0); /* NORETURN */
}
inetaddrs[0] = addr.sin_addr;
addrlen = sizeof(addr);
if (getpeername(clientSocket, (struct sockaddr *) &addr, &addrlen) != 0) {
syslog(LOG_ERR, "CTRL: getpeername() failed");
syslog_perror("getpeername");
close(clientSocket);
bail(0); /* NORETURN */
}
inetaddrs[1] = addr.sin_addr;
/* Set non-blocking */
if ((flags = fcntl(clientSocket, F_GETFL, arg /* ignored */)) == -1 ||
fcntl(clientSocket, F_SETFL, flags|OUR_NB_MODE) == -1) {
syslog(LOG_ERR, "CTRL: Failed to set client socket non-blocking");
syslog_perror("fcntl");
close(clientSocket);
bail(0); /* NORETURN */
}
/* Fiddle with argv */
my_setproctitle(gargc, gargv, "pptpd [%s]%20c",
inet_ntoa(addr.sin_addr), ' ');
/* be ready for a grisly death */
sigpipe_create();
sigpipe_assign(SIGTERM);
NOTE_VALUE(PAC, call_id_pair, htons(-1));
NOTE_VALUE(PNS, call_id_pair, htons(-1));
syslog(LOG_INFO, "CTRL: Client %s control connection started", inet_ntoa(addr.sin_addr));
pptp_handle_ctrl_connection(pppaddrs, inetaddrs);
syslog(LOG_DEBUG, "CTRL: Reaping child PPP[%i]", pppfork);
if (pppfork > 0)
waitpid(pppfork, NULL, 0);
syslog(LOG_INFO, "CTRL: Client %s control connection finished", inet_ntoa(addr.sin_addr));
bail(0); /* NORETURN */
return 1; /* make gcc happy */
}
/*
* pptp_handle_ctrl_connection
*
* 1. read a packet (should be start_ctrl_conn_rqst)
* 2. reply to packet (send a start_ctrl_conn_rply)
* 3. proceed with GRE and CTRL connections
*
* args: pppaddrs - ppp local and remote addresses (strings)
* inetaddrs - local and client socket address
* retn: 0 success, -1 failure
*/
static void pptp_handle_ctrl_connection(char **pppaddrs, struct in_addr *inetaddrs)
{
/* For echo requests used to check link is alive */
int echo_wait = FALSE; /* Waiting for echo? */
u_int32_t echo_count = 0; /* Sequence # of echo */
time_t echo_time = 0; /* Time last echo req sent */
struct timeval idleTime; /* How long to select() */
/* General local variables */
ssize_t rply_size; /* Reply packet size */
fd_set fds; /* For select() */
int maxfd = clientSocket; /* For select() */
int send_packet; /* Send a packet this time? */
#if BSDUSER_PPP || SLIRP
/* not needed by stuff which uses socketpair() in startCall() */
#define init 1
#else
int init = 0; /* Has pppd initialized the pty? */
#endif
int pty_fd = -1; /* File descriptor of pty */
int gre_fd = -1; /* Network file descriptor */
int sig_fd = sigpipe_fd(); /* Signal pipe descriptor */
unsigned char packet[PPTP_MAX_CTRL_PCKT_SIZE];
unsigned char rply_packet[PPTP_MAX_CTRL_PCKT_SIZE];
for (;;) {
FD_ZERO(&fds);
FD_SET(sig_fd, &fds);
FD_SET(clientSocket, &fds);
if (pty_fd != -1)
FD_SET(pty_fd, &fds);
if (gre_fd != -1 && init)
FD_SET(gre_fd, &fds);
/* set timeout */
if (encaps_gre(-1, NULL, 0) || decaps_hdlc(-1, NULL, 0)) {
idleTime.tv_sec = 0;
idleTime.tv_usec = 50000; /* don't ack immediately */
} else {
idleTime.tv_sec = IDLE_WAIT;
idleTime.tv_usec = 0;
}
/* default: do nothing */
send_packet = FALSE;
switch (select(maxfd + 1, &fds, NULL, NULL, &idleTime)) {
case -1: /* Error with select() */
if (errno != EINTR)
syslog(LOG_ERR, "CTRL: Error with select(), quitting");
goto leave_clear_call;
case 0:
if (decaps_hdlc(-1, NULL, 0)) {
if(decaps_hdlc(-1, encaps_gre, gre_fd))
syslog(LOG_ERR, "CTRL: GRE re-xmit failed");
} else if (encaps_gre(-1, NULL, 0))
/* Pending ack and nothing else to do */
encaps_gre(gre_fd, NULL, 0); /* send ack with no payload */
else if (echo_wait != TRUE) {
/* Timeout. Start idle link detection. */
echo_count++;
if (pptpctrl_debug)
syslog(LOG_DEBUG, "CTRL: Sending ECHO REQ id %d", echo_count);
time(&echo_time);
make_echo_req_packet(rply_packet, &rply_size, echo_count);
echo_wait = TRUE;
send_packet = TRUE;
}
break;
default:
break;
}
/* check for pending SIGTERM delivery */
if (FD_ISSET(sig_fd, &fds)) {
if (sigpipe_read() == SIGTERM)
bail(SIGTERM);
}
/* detect startup of pppd */
#ifndef init
if (!init && pty_fd != -1 && FD_ISSET(pty_fd, &fds))
init = 1;
#endif
/* handle actual packets */
/* send from pty off via GRE */
if (pty_fd != -1 && FD_ISSET(pty_fd, &fds) && decaps_hdlc(pty_fd, encaps_gre, gre_fd) < 0) {
syslog(LOG_ERR, "CTRL: PTY read or GRE write failed (pty,gre)=(%d,%d)", pty_fd, gre_fd);
break;
}
/* send from GRE off to pty */
if (gre_fd != -1 && FD_ISSET(gre_fd, &fds) && decaps_gre(gre_fd, encaps_hdlc, pty_fd) < 0) {
if (gre_fd == 6 && pty_fd == 5) {
syslog(LOG_ERR, "CTRL: GRE-tunnel has collapsed (GRE read or PTY write failed (gre,pty)=(%d,%d))", gre_fd, pty_fd);
} else {
syslog(LOG_ERR, "CTRL: GRE read or PTY write failed (gre,pty)=(%d,%d)", gre_fd, pty_fd);
}
break;
}
/* handle control messages */
if (FD_ISSET(clientSocket, &fds)) {
send_packet = TRUE;
switch (read_pptp_packet(clientSocket, packet, rply_packet, &rply_size)) {
case 0:
syslog(LOG_ERR, "CTRL: CTRL read failed");
goto leave_drop_call;
case -1:
send_packet = FALSE;
break;
case STOP_CTRL_CONN_RQST:
if (pptpctrl_debug)
syslog(LOG_DEBUG, "CTRL: Received STOP CTRL CONN request (disconnecting)");
if (gre_fd != -1 || pty_fd != -1)
syslog(LOG_WARNING, "CTRL: Request to close control connection when call is open, closing");
send_pptp_packet(clientSocket, rply_packet, rply_size);
goto leave_drop_call;
case CALL_CLR_RQST:
if(pptpctrl_debug)
syslog(LOG_DEBUG, "CTRL: Received CALL CLR request (closing call)");
if (gre_fd == -1 || pty_fd == -1)
syslog(LOG_WARNING, "CTRL: Request to close call but call not open");
if (gre_fd != -1) {
FD_CLR(gre_fd, &fds);
close(gre_fd);
gre_fd = -1;
}
if (pty_fd != -1) {
FD_CLR(pty_fd, &fds);
close(pty_fd);
pty_fd = -1;
}
/* violating RFC */
goto leave_drop_call;
case OUT_CALL_RQST:
/* for killing off the link later (ugly) */
NOTE_VALUE(PAC, call_id_pair, ((struct pptp_out_call_rply *) (rply_packet))->call_id);
NOTE_VALUE(PNS, call_id_pair, ((struct pptp_out_call_rply *) (rply_packet))->call_id_peer);
if (gre_fd != -1 || pty_fd != -1) {
syslog(LOG_WARNING, "CTRL: Request to open call when call is already open, closing");
if (gre_fd != -1) {
FD_CLR(gre_fd, &fds);
close(gre_fd);
gre_fd = -1;
}
if (pty_fd != -1) {
FD_CLR(pty_fd, &fds);
close(pty_fd);
pty_fd = -1;
}
}
/* change process title for accounting and status scripts */
my_setproctitle(gargc, gargv,
"pptpd [%s:%04X - %04X]",
inet_ntoa(inetaddrs[1]),
ntohs(((struct pptp_out_call_rply *) (rply_packet))->call_id_peer),
ntohs(((struct pptp_out_call_rply *) (rply_packet))->call_id));
/* start the call, by launching pppd */
syslog(LOG_INFO, "CTRL: Starting call (launching pppd, opening GRE)");
pty_fd = startCall(pppaddrs, inetaddrs);
if (pty_fd > maxfd) maxfd = pty_fd;
if ((gre_fd = pptp_gre_init(call_id_pair, pty_fd, inetaddrs)) > maxfd)
maxfd = gre_fd;
break;
case ECHO_RPLY:
if (echo_wait == TRUE && ((struct pptp_echo_rply *) (packet))->identifier == echo_count)
echo_wait = FALSE;
else
syslog(LOG_WARNING, "CTRL: Unexpected ECHO REPLY packet");
/* FALLTHRU */
case SET_LINK_INFO:
send_packet = FALSE;
break;
#ifdef PNS_MODE
case IN_CALL_RQST:
case IN_CALL_RPLY:
case IN_CALL_CONN:
#endif
case CALL_DISCONN_NTFY:
case STOP_CTRL_CONN_RPLY:
/* These don't generate replies. Also they come from things we don't send in this section. */
syslog(LOG_WARNING, "CTRL: Got a reply to a packet we didn't send");
send_packet = FALSE;
break;
/* Otherwise, the already-formed reply will do fine, so send it */
}
}
/* send reply packet - this may block, but it should be very rare */
if (send_packet == TRUE && send_pptp_packet(clientSocket, rply_packet, rply_size) < 0) {
syslog(LOG_ERR, "CTRL: Error sending GRE, aborting call");
goto leave_clear_call;
}
/* waiting for echo reply and curtime - echo_time > max wait */
if (echo_wait == TRUE && (time(NULL) - echo_time) > MAX_ECHO_WAIT) {
syslog(LOG_INFO, "CTRL: Session timed out, ending call");
goto leave_clear_call;
}
}
/* Finished! :-) */
leave_drop_call:
NOTE_VALUE(PAC, call_id_pair, htons(-1));
NOTE_VALUE(PNS, call_id_pair, htons(-1));
close(clientSocket);
leave_clear_call:
/* leave clientSocket and call_id_pair alone for bail() */
if (gre_fd != -1)
close(gre_fd);
gre_fd = -1;
if (pty_fd != -1)
close(pty_fd);
pty_fd = -1;
return;
#ifdef init
#undef init
#endif
}
/*
* pptp_handle_ctrl_connection
*
* 1. read a packet (should be start_ctrl_conn_rqst)
* 2. reply to packet (send a start_ctrl_conn_rply)
* 3. proceed with GRE and CTRL connections
*
* args: pppaddrs - ppp local and remote addresses (strings)
* inetaddrs - local and client socket address
* retn: 0 success, -1 failure
*/
static void pptp_handle_ctrl_connection(char **pppaddrs, struct in_addr *inetaddrs)
{
/* For echo requests used to check link is alive */
int echo_wait = FALSE; /* Waiting for echo? */
u_int32_t echo_count = 0; /* Sequence # of echo */
time_t echo_time = 0; /* Time last echo req sent */
struct timeval idleTime; /* How long to select() */
/* General local variables */
ssize_t rply_size; /* Reply packet size */
fd_set fds; /* For select() */
int maxfd = clientSocket; /* For select() */
int send_packet; /* Send a packet this time? */
#if BSDUSER_PPP || SLIRP
/* not needed by stuff which uses socketpair() in startCall() */
#define init 1
#else
int init = 0; /* Has pppd initialized the pty? */
#endif
int sig_fd = sigpipe_fd(); /* Signal pipe descriptor */
unsigned char packet[PPTP_MAX_CTRL_PCKT_SIZE];
unsigned char rply_packet[PPTP_MAX_CTRL_PCKT_SIZE];
struct sockaddr_pppox dst_addr;
for (;;) {
FD_ZERO(&fds);
FD_SET(sig_fd, &fds);
FD_SET(clientSocket, &fds);
/* set timeout */
idleTime.tv_sec = IDLE_WAIT;
idleTime.tv_usec = 0;
/* default: do nothing */
send_packet = FALSE;
switch (select(maxfd + 1, &fds, NULL, NULL, &idleTime)) {
case -1: /* Error with select() */
if (errno != EINTR)
syslog(LOG_ERR, "CTRL: Error with select(), quitting");
goto leave_clear_call;
case 0:
if (echo_wait != TRUE) {
/* Timeout. Start idle link detection. */
echo_count++;
if (pptpctrl_debug)
syslog(LOG_DEBUG, "CTRL: Sending ECHO REQ id %d", echo_count);
time(&echo_time);
make_echo_req_packet(rply_packet, &rply_size, echo_count);
echo_wait = TRUE;
send_packet = TRUE;
}
break;
default:
break;
}
/* check for pending SIGTERM delivery */
if (FD_ISSET(sig_fd, &fds)) {
if (sigpipe_read() == SIGTERM)
bail(SIGTERM);
}
/* handle control messages */
if (FD_ISSET(clientSocket, &fds)) {
send_packet = TRUE;
switch (read_pptp_packet(clientSocket, packet, rply_packet, &rply_size)) {
case 0:
syslog(LOG_ERR, "CTRL: CTRL read failed");
goto leave_drop_call;
case -1:
send_packet = FALSE;
break;
case STOP_CTRL_CONN_RQST:
if (pptpctrl_debug)
syslog(LOG_DEBUG, "CTRL: Received STOP CTRL CONN request (disconnecting)");
send_pptp_packet(clientSocket, rply_packet, rply_size);
goto leave_drop_call;
case CALL_CLR_RQST:
if(pptpctrl_debug)
syslog(LOG_DEBUG, "CTRL: Received CALL CLR request (closing call)");
/* violating RFC */
goto leave_drop_call;
case OUT_CALL_RQST:
/* for killing off the link later (ugly) */
NOTE_VALUE(PAC, call_id_pair, ((struct pptp_out_call_rply *) (rply_packet))->call_id);
NOTE_VALUE(PNS, call_id_pair, ((struct pptp_out_call_rply *) (rply_packet))->call_id_peer);
pptp_timeout*=1000;
if (setsockopt(pptp_sock,0,PPTP_SO_TIMEOUT,&pptp_timeout,sizeof(pptp_timeout)))
syslog(LOG_WARNING,"CTRL: failed to setsockopt SO_TIMEOUT\n");
dst_addr.sa_family=AF_PPPOX;
dst_addr.sa_protocol=PX_PROTO_PPTP;
dst_addr.sa_addr.pptp.call_id=htons(((struct pptp_out_call_rply *) (rply_packet))->call_id_peer);
dst_addr.sa_addr.pptp.sin_addr=inetaddrs[1];
if (connect(pptp_sock,(struct sockaddr*)&dst_addr,sizeof(dst_addr))){
syslog(LOG_ERR,"CTRL: failed to connect PPTP socket (%s)\n",strerror(errno));
exit(-1);
break;
}
/* change process title for accounting and status scripts */
my_setproctitle(gargc, gargv,
"pptpd [%s:%04X - %04X]",
inet_ntoa(inetaddrs[1]),
ntohs(((struct pptp_out_call_rply *) (rply_packet))->call_id_peer),
ntohs(((struct pptp_out_call_rply *) (rply_packet))->call_id));
/* start the call, by launching pppd */
syslog(LOG_INFO, "CTRL: Starting call (launching pppd, opening GRE)");
startCall(pppaddrs, inetaddrs);
if (PPP_WAIT) {
switch(ioctl(pptp_sock,PPPTPIOWFP,PPP_WAIT)){
case -1:
syslog(LOG_ERR,
"CTRL: waiting for first packet failed, ignoring");
break;
case 0:
syslog(LOG_ERR,
"CTRL: timeout waiting for first packet");
break;
}
}
close(pptp_sock);
pptp_sock=-1;
break;
case ECHO_RPLY:
if (echo_wait == TRUE && ((struct pptp_echo_rply *) (packet))->identifier == echo_count)
echo_wait = FALSE;
else
syslog(LOG_WARNING, "CTRL: Unexpected ECHO REPLY packet");
/* FALLTHRU */
case SET_LINK_INFO:
send_packet = FALSE;
break;
#ifdef PNS_MODE
case IN_CALL_RQST:
case IN_CALL_RPLY:
case IN_CALL_CONN:
#endif
case CALL_DISCONN_NTFY:
case STOP_CTRL_CONN_RPLY:
/* These don't generate replies. Also they come from things we don't send in this section. */
syslog(LOG_WARNING, "CTRL: Got a reply to a packet we didn't send");
send_packet = FALSE;
break;
/* Otherwise, the already-formed reply will do fine, so send it */
}
}
/* send reply packet - this may block, but it should be very rare */
if (send_packet == TRUE && send_pptp_packet(clientSocket, rply_packet, rply_size) < 0) {
syslog(LOG_ERR, "CTRL: Error sending GRE, aborting call");
goto leave_clear_call;
}
/* waiting for echo reply and curtime - echo_time > max wait */
if (echo_wait == TRUE && (time(NULL) - echo_time) > MAX_ECHO_WAIT) {
syslog(LOG_INFO, "CTRL: Session timed out, ending call");
goto leave_clear_call;
}
}
/* Finished! :-) */
leave_drop_call:
NOTE_VALUE(PAC, call_id_pair, htons(-1));
NOTE_VALUE(PNS, call_id_pair, htons(-1));
close(clientSocket);
leave_clear_call:
return;
#ifdef init
#undef init
#endif
}