Pass remotenumber to pppd.

doc/l2tpd.conf.sample

@@ -47,6 +47,7 @@
 ; rx bps = 10000000				; Receive tunnel speed
 ; tx bps = 10000000				; Transmit tunnel speed
 ; bps = 100000					; Define both receive and transmit speed in one option
+; trust remotenumber = no			; Trust dialing number AVP?
 
 ; [lac marko]							; Example VPN LAC definition
 ; lns = lns.marko.net					; * Who is our LNS?

doc/xl2tpd.conf.5

@@ -175,6 +175,12 @@ This will enable the debug for pppd.
 .B pass peer
 Pass the peer's IP address to pppd as ipparam. Enabled by default.
 
+.TP
+.B trust remotenumber
+When this is set to yes xl2tpd will trust the dialing number AVP and provide
+that as the remotenumber to pppd rather than the peer's IP address.  Default is
+not trusted.
+
 .TP 
 .B pppoptfile
 Specify the path for a file which contains pppd configuration parameters

file.c

@@ -676,6 +676,22 @@ int set_pass_peer (char *word, char *value, int context, void *item)
     return 0;
 }
 
+int set_trust_remotenumber (char *word, char *value, int context, void *item)
+{
+    switch (context & ~CONTEXT_DEFAULT)
+    {
+    case CONTEXT_LNS:
+        if (set_boolean (word, value, &(((struct lns *) item)->trust_remotenumber)))
+            return -1;
+        break;
+    default:
+        snprintf (filerr, sizeof (filerr), "'%s' not valid in this context\n",
+                  word);
+        return -1;
+    }
+    return 0;
+}
+
 int set_pppoptfile (char *word, char *value, int context, void *item)
 {
     struct lac *l = (struct lac *) item;
@@ -1611,6 +1627,7 @@ struct keyword words[] = {
     {"hostname", &set_hostname},
     {"ppp debug", &set_debug},
     {"pass peer", &set_pass_peer},
+    {"trust remotenumber", &set_trust_remotenumber},
     {"pppoptfile", &set_pppoptfile},
     {"call rws", &set_rws},
     {"tunnel rws", &set_rws},

file.h

@@ -97,6 +97,7 @@ struct lns
     int proxyauth;              /* Allow proxy authentication? */
     int debug;                  /* Debug PPP? */
     int pass_peer;              /* Pass peer IP to pppd as ipparam? */
+    int trust_remotenumber;     /* Whether or not to trust remotely supplied "Dialing Number" AVP */
     char pppoptfile[STRLEN];    /* File containing PPP options */
     struct tunnel *t;           /* Tunnel of this, if it's ready */
 };

xl2tpd.c

@@ -495,6 +495,14 @@ int start_pppd (struct call *c, struct ppp_opts *opts)
     }
 
     {
+        stropt[pos++] = strdup("remotenumber");
+        if (c->dialing[0] && (!c->lns || c->lns->trust_remotenumber)) {
+            /* if a remotenumber is available, and we're a LAC or the remote "dialing number" AVP is trusted */
+            stropt[pos++] = strdup(c->dialing);
+        } else {
+            stropt[pos++] = strdup(IPADDY(c->container->peer.sin_addr));
+        }
+
         struct ppp_opts *p = opts;
         int maxn_opts = sizeof(stropt) / sizeof(stropt[0]) - 1;
         while (p && pos < maxn_opts)