OpenWrt Forum Archive

l2tpd doesn't work because the kernel is compiled with CONFIG_UNIX98_PTYS enabled. The following patch (needs to go in openwrt/package/l2tpd/patches) makes it work without having to compile a custom kernel, I adapted it from http://www.jacco2.dds.nl/networking/fre … onfigLinux.

--- l2tpd-0.70-pre20031121.orig/l2tpd.c    2005-09-25 14:54:09.000000000 +0200
+++ l2tpd-0.70-pre20031121/l2tpd.c    2005-09-25 15:02:31.000000000 +0200
@@ -14,6 +14,7 @@
  */
 
 #include <stdlib.h>
+#include <sys/types.h>
 #include <sys/utsname.h>
 #include <sys/stat.h>
 #include <sys/wait.h>
@@ -259,8 +260,8 @@ void death_handler (int signal)
 
 int start_pppd (struct call *c, struct ppp_opts *opts)
 {
-    char a, b;
-    char tty[80];
+    /* char a, b; */
+    char *tty;
     char *stropt[80];
     struct ppp_opts *p;
 #ifdef USE_KERNEL
@@ -309,12 +310,45 @@ int start_pppd (struct call *c, struct p
     else
     {
 #endif
-        if ((c->fd = getPtyMaster (&a, &b)) < 0)
+    c->fd = open("/dev/ptmx", O_RDWR | O_NONBLOCK);
+    if (c->fd == -1)
+    {
+        log (LOG_WARN, "%s: unable to open /dev/ptmx to allocate pty\n",
+                __FUNCTION__);
+        return -EINVAL;
+    } else
+    {
+        if (grantpt(c->fd))
+        {
+        log (LOG_WARN, "%s: unable to grantpt() on pty\n",
+                __FUNCTION__);
+        close(c->fd);
+        return -EINVAL;
+        }
+        if (unlockpt(c->fd))
+        {
+        log (LOG_WARN, "%s: unable to unlockpt() on pty\n",
+            __FUNCTION__);
+        close(c->fd);
+        return -EINVAL;
+        }
+        tty = ptsname(c->fd);
+        if (tty == NULL)
+        {
+        log (LOG_WARN, "%s: unable to obtain name of slave tty\n",
+            __FUNCTION__);
+        close(c->fd);
+        return -EINVAL;
+        }
+    }
+    
+    
+ /*    if ((c->fd = getPtyMaster (&a, &b)) < 0)
         {
             log (LOG_WARN, "%s: unable to allocate pty, abandoning!\n",
                  __FUNCTION__);
             return -EINVAL;
-        }
+        } */
 
         /* set fd opened above to not echo so we don't see read our own packets
            back of the file descriptor that we just wrote them to */
@@ -323,8 +357,8 @@ int start_pppd (struct call *c, struct p
         ptyconf.c_cflag &= ~(ICANON | ECHO);
         tcsetattr (c->fd, TCSANOW, &ptyconf);
 
-        snprintf (tty, sizeof (tty), "/dev/tty%c%c", a, b);
+/*        snprintf (tty, sizeof (tty), "/dev/tty%c%c", a, b); */
         fd2 = open (tty, O_RDWR);
         if(!fd2)
             log(LOG_WARN, "unable to open tty %s", tty);

I don't get a clean patch into the original file:

$ patch -p0 < l2tpd.patch
patching file l2tpd-0.70-pre20031121.orig/l2tpd.c
Hunk #1 succeeded at 16 (offset 2 lines).
Hunk #2 succeeded at 272 (offset 12 lines).
Hunk #3 succeeded at 322 (offset 12 lines).
Hunk #4 FAILED at 369.
1 out of 4 hunks FAILED -- saving rejects to file l2tpd-0.70-pre20031121.orig/l2tpd.c.rej

Here's the .rej file:

***************
*** 335,342 ****
ptyconf.c_cflag &= ~(ICANON | ECHO);
tcsetattr (c->fd, TCSANOW, &ptyconf);

- snprintf (tty, sizeof (tty), "/dev/tty%c%c", a, b);
fd2 = open (tty, O_RDWR);
if(!fd2)
log(LOG_WARN, "unable to open tty %s", tty);

--- 369,376 ----
ptyconf.c_cflag &= ~(ICANON | ECHO);
tcsetattr (c->fd, TCSANOW, &ptyconf);

+ /* snprintf (tty, sizeof (tty), "/dev/tty%c%c", a, b); */
fd2 = open (tty, O_RDWR);
if(!fd2)
log(LOG_WARN, "unable to open tty %s", tty);