+ strlcpy(slave_name, pty_name, 16);
+ *master_fdp = mfd;
+ *slave_fdp = sfd;
+ if (tcgetattr(sfd, &tios) == 0) {
+ tios.c_cflag &= ~(CSIZE | CSTOPB | PARENB);
+ tios.c_cflag |= CS8 | CREAD;
+ tios.c_iflag = IGNPAR | CLOCAL;
+ tios.c_oflag = 0;
+ tios.c_lflag = 0;
+ if (tcsetattr(sfd, TCSAFLUSH, &tios) < 0)
+ warn("couldn't set attributes on pty: %m");
+ } else
+ warn("couldn't get attributes on pty: %m");
+
+ return 1;
+}
+
+/********************************************************************
+ *
+ * open_loopback - open the device we use for getting packets
+ * in demand mode. Under Linux, we use a pty master/slave pair.
+ */
+int
+open_ppp_loopback(void)
+{
+ int flags;
+
+ looped = 1;
+ if (new_style_driver) {
+ /* allocate ourselves a ppp unit */
+ ifunit = -1;
+ if (ioctl(ppp_dev_fd, PPPIOCNEWUNIT, &ifunit) < 0)
+ fatal("Couldn't create PPP unit: %m");
+ set_flags(ppp_dev_fd, SC_LOOP_TRAFFIC);
+ set_kdebugflag(kdebugflag);
+ ppp_fd = -1;
+ return ppp_dev_fd;
+ }
+
+ if (!get_pty(&master_fd, &slave_fd, loop_name, 0))
+ fatal("No free pty for loopback");
+ SYSDEBUG(("using %s for loopback", loop_name));
+
+ set_ppp_fd(slave_fd);
+
+ flags = fcntl(master_fd, F_GETFL);
+ if (flags == -1 ||
+ fcntl(master_fd, F_SETFL, flags | O_NONBLOCK) == -1)
+ warn("couldn't set master loopback to nonblock: %m(%d)", errno);
+
+ flags = fcntl(ppp_fd, F_GETFL);
+ if (flags == -1 ||
+ fcntl(ppp_fd, F_SETFL, flags | O_NONBLOCK) == -1)
+ warn("couldn't set slave loopback to nonblock: %m(%d)", errno);
+
+ if (ioctl(ppp_fd, TIOCSETD, &ppp_disc) < 0)
+ fatal("ioctl(TIOCSETD): %m(%d)", errno);
+/*
+ * Find out which interface we were given.
+ */
+ if (ioctl(ppp_fd, PPPIOCGUNIT, &ifunit) < 0)
+ fatal("ioctl(PPPIOCGUNIT): %m(%d)", errno);
+/*
+ * Enable debug in the driver if requested.
+ */
+ set_kdebugflag (kdebugflag);
+
+ return master_fd;
+}
+
+/********************************************************************
+ *
+ * restore_loop - reattach the ppp unit to the loopback.
+ *
+ * The kernel ppp driver automatically reattaches the ppp unit to
+ * the loopback if the serial port is set to a line discipline other
+ * than ppp, or if it detects a modem hangup. The former will happen
+ * in disestablish_ppp if the latter hasn't already happened, so we
+ * shouldn't need to do anything.
+ *
+ * Just to be sure, set the real serial port to the normal discipline.
+ */
+
+void
+restore_loop(void)
+{
+ looped = 1;
+ if (new_style_driver) {
+ set_flags(ppp_dev_fd, get_flags(ppp_dev_fd) | SC_LOOP_TRAFFIC);
+ return;
+ }
+ if (ppp_fd != slave_fd) {
+ (void) ioctl(ppp_fd, TIOCSETD, &tty_disc);
+ set_ppp_fd(slave_fd);
+ }
+}
+
+/********************************************************************
+ *
+ * sifnpmode - Set the mode for handling packets for a given NP.
+ */