+/*
+ * open_ppp_loopback - open the device we use for getting
+ * packets in demand mode, and connect it to a ppp interface.
+ * Here we use a pty.
+ */
+void
+open_ppp_loopback()
+{
+ int flags;
+ struct termios tios;
+ int pppdisc = PPPDISC;
+
+ if (openpty(&loop_master, &loop_slave, loop_name, NULL, NULL) < 0) {
+ syslog(LOG_ERR, "No free pty for loopback");
+ die(1);
+ }
+ SYSDEBUG((LOG_DEBUG, "using %s for loopback", loop_name));
+
+ if (tcgetattr(loop_slave, &tios) == 0) {
+ tios.c_cflag &= ~(CSIZE | CSTOPB | PARENB);
+ tios.c_cflag |= CS8 | CREAD;
+ tios.c_iflag = IGNPAR;
+ tios.c_oflag = 0;
+ tios.c_lflag = 0;
+ if (tcsetattr(loop_slave, TCSAFLUSH, &tios) < 0)
+ syslog(LOG_WARNING, "couldn't set attributes on loopback: %m");
+ }
+
+ if ((flags = fcntl(loop_master, F_GETFL)) != -1)
+ if (fcntl(loop_master, F_SETFL, flags | O_NONBLOCK) == -1)
+ syslog(LOG_WARNING, "couldn't set loopback to nonblock: %m");
+
+ ppp_fd = loop_slave;
+ if (ioctl(ppp_fd, TIOCSETD, &pppdisc) < 0) {
+ syslog(LOG_ERR, "ioctl(TIOCSETD): %m");
+ die(1);
+ }
+
+ /*
+ * Find out which interface we were given.
+ */
+ if (ioctl(ppp_fd, PPPIOCGUNIT, &ifunit) < 0) {
+ syslog(LOG_ERR, "ioctl(PPPIOCGUNIT): %m");
+ die(1);
+ }
+
+ /*
+ * Enable debug in the driver if requested.
+ */
+ if (kdebugflag) {
+ if (ioctl(ppp_fd, PPPIOCGFLAGS, (caddr_t) &flags) < 0) {
+ syslog(LOG_WARNING, "ioctl (PPPIOCGFLAGS): %m");
+ } else {
+ flags |= (kdebugflag & 0xFF) * SC_DEBUG;
+ if (ioctl(ppp_fd, PPPIOCSFLAGS, (caddr_t) &flags) < 0)
+ syslog(LOG_WARNING, "ioctl(PPPIOCSFLAGS): %m");
+ }
+ }
+
+}
+
+