Re: Support for L2TP/IPsec

[Vincent Bernat <bernat luffy cx>]

OoO En ce  doux début de matinée  du samedi 24 mai 2008,  vers 08:44, je
disais:

>> We might have to patch xl2tpd then; I understand why they did it, but
>> passing files around is just broken.

> Hi Dan!

> I will propose a patch for xl2tpd to be able to do anything from command
> line (for a  client only) and I  will try to push the  patch upstream. I
> keep you in touch.

Hi Dan!

I have proposed a patch to  upstream that would allow to use xl2tpd just
like pppd. I attach the patch  to this message. xl2tpd should be invoked
like this:
 xl2tpd --simple <hostname> <pppd args>

This  patch needs  more work.  For example,  if the  host  is incorrect,
xl2tpd will  just wait forever but  I think this  is a good start  for a
prototype.

diff --git a/doc/xl2tpd.8 b/doc/xl2tpd.8
index fa86355..b2b8f47 100644
--- a/doc/xl2tpd.8
+++ b/doc/xl2tpd.8
@@ -40,6 +40,12 @@ Tells xl2tpd to use an alternate pid file.  Default is
 Tells xl2tpd to use an alternate control file.  Default is
 /var/run/xl2tpd/l2tp-control
 
+.TP 
+.B --simple host args
+Tells xl2tpd to connect to "host" and pass the given args to pppd.
+This mode prevents xl2tpd to daemonize itself. It is aimed at allowing
+LAC connection without any config file.
+
 
 .SH "FILES"
 
diff --git a/file.c b/file.c
index 3072022..b84183c 100644
--- a/file.c
+++ b/file.c
@@ -33,6 +33,9 @@ struct global gconfig;
 char filerr[STRLEN];
 
 int parse_config (FILE *);
+struct lac *new_lac ();
+int set_lns (char *word, char *value, int context, void *item);
+int set_autodial (char *word, char *value, int context, void *item);
 struct keyword words[];
 
 int init_config ()
@@ -51,6 +54,14 @@ int init_config ()
     laclist = NULL;
     deflac = (struct lac *) malloc (sizeof (struct lac));
 
+    if (gconfig.simple)
+    {
+        laclist = new_lac();
+        strncpy(laclist->entname, gconfig.host, sizeof(laclist->entname));
+        set_lns("lns", gconfig.host, CONTEXT_LAC, laclist);
+        set_autodial("autodial", "yes", CONTEXT_LAC, laclist);
+        return 0;
+    }
     f = fopen (gconfig.configfile, "r");
     if (!f) 
     {
diff --git a/file.h b/file.h
index f5488e5..06074a7 100644
--- a/file.h
+++ b/file.h
@@ -153,6 +153,10 @@ struct global
     int debug_tunnel;		/* Print tunnel debugging info? */
     int debug_state;		/* Print FSM debugging info? */
     int ipsecsaref;
+    int simple;                 /* Simple LAC mode */
+    char host[STRLEN];          /* Host to connect in simple LAC mode */
+    char **pppdargs;            /* Args for pppd */
+    int pppdargs_c;
 };
 
 extern struct global gconfig;   /* Global configuration options */
diff --git a/xl2tpd.c b/xl2tpd.c
index a423101..a3aef34 100644
--- a/xl2tpd.c
+++ b/xl2tpd.c
@@ -295,6 +295,7 @@ int start_pppd (struct call *c, struct ppp_opts *opts)
     char tty[512];
     char *stropt[80];
     struct ppp_opts *p;
+    char **q;
 #ifdef USE_KERNEL
     struct sockaddr_pppol2tp sax;
     int flags;
@@ -317,6 +318,18 @@ int start_pppd (struct call *c, struct ppp_opts *opts)
         pos++;
         p = p->next;
     }
+    if (gconfig.simple)
+    {
+        q = gconfig.pppdargs;
+        while(gconfig.pppdargs_c)
+        {
+        stropt[pos] = (char *) malloc (strlen (*q) + 1);
+        strncpy (stropt[pos], *q, strlen (*q) + 1);
+        pos++;
+        q++;
+        gconfig.pppdargs_c--;
+        }
+    }
     stropt[pos] = NULL;
     if (c->pppd > 0)
     {
@@ -1027,7 +1040,7 @@ void do_control ()
 
 void usage(void) {
     printf("\nxl2tpd version:  %s\n",SERVER_VERSION);
-    printf("Usage: xl2tpd [-c <config file>] [-s <secret file>] [-p <pid file>]  \n             [-C <control file>] [-D]\n");
+    printf("Usage: xl2tpd [--simple host args | [-c <config file>] [-s <secret file>] [-p <pid file>]  \n             [-C <control file>] [-D]]\n");
     printf("\n");
     exit(1);
 }
@@ -1056,12 +1069,31 @@ void init_args(int argc, char *argv[])
     strncpy(gconfig.controlfile,CONTROL_PIPE,
             sizeof(gconfig.controlfile) - 1);
     gconfig.ipsecsaref = 0;
+    gconfig.simple = 0;
+    memset(gconfig.host,0,STRLEN);
+    gconfig.pppdargs = NULL;
+    gconfig.pppdargs_c = 0;
 
     for (i = 1; i < argc; i++) {
         if (! strncmp(argv[i],"--version",9)) {
             printf("\nxl2tpd version:  %s\n",SERVER_VERSION);
             exit(1);
         }
+        if (! strncmp(argv[i],"--simple",6)) {
+            if (i != 1)
+                usage();
+            else if (++i == argc)
+                usage();
+            else {
+                strncpy(gconfig.host,argv[i],
+                        sizeof(gconfig.host) - 1);
+                gconfig.pppdargs = &argv[++i];
+                gconfig.pppdargs_c = argc-3;
+                gconfig.daemon = 0;
+                gconfig.simple = 1;
+                break;
+            }
+        }
 
         if(! strncmp(argv[i],"-c",2)) {
             if(++i == argc)

-- 
Don't patch bad code - rewrite it.
            - The Elements of Programming Style (Kernighan & Plauger)