#37 Protocol errors related to ICMP/GRE

[Dr Bradley Schatz]

Hi,

As per this unresolved discussion in the list [1], I have
been having the same problems. I patched up the most
recent pptpctrl.c of pptpd as below. Everything works
now.

Cheers

-b

[1] http://marc.theaimsgroup.com/?l=poptop-
server&m=109301203710004&w=2

--- pptpd-1.2.1/pptpctrl.c Wed Apr 28 13:36:07
2004
+++ pptpd-1.2.1-geht/pptpctrl.c Fri Aug 20 15:36:52
2004
@@ -233,6 +233,7 @@
#endif
int pty_fd = -1; / File
descriptor of pty /
int gre_fd = -1; / Network
file descriptor /

• int running = 0;

  unsigned char packet
  [PPTP_MAX_CTRL_PCKT_SIZE];
  unsigned char rply_packet
  [PPTP_MAX_CTRL_PCKT_SIZE];
  @@ -294,14 +295,17 @@
  #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) { + if (running && 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))
• running=1;
  +
  if (gre_fd != -1 && FD_ISSET
  (gre_fd, &fds) && decaps_gre(gre_fd, encaps_hdlc, \
  pty_fd) < 0) { + running=1;
  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 {