Add mac address config option handling

[l2tpns.git] / l2tpns.c

diff --git a/l2tpns.c b/l2tpns.c
index eb7783b..7d726cb 100644 (file)
--- a/l2tpns.c
+++ b/l2tpns.c
@@ -4,7 +4,7 @@
 // Copyright (c) 2002 FireBrick (Andrews & Arnold Ltd / Watchfront Ltd) - GPL licenced
 // vim: sw=8 ts=8
 
-char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.25 2004/09/02 04:18:07 fred_nerk Exp $";
+char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.28 2004/09/20 23:34:35 fred_nerk Exp $";
 
 #include <arpa/inet.h>
 #include <assert.h>
@@ -57,7 +57,7 @@ int snoopfd = -1;             // UDP file handle for sending out intercept data
 int *radfds = NULL;            // RADIUS requests file handles
 int ifrfd = -1;                        // File descriptor for routing, etc
 time_t basetime = 0;           // base clock
-char hostname[1000] = "";      // us.
+char *hostname = NULL;         // us.
 int tunidx;                    // ifr_ifindex of tun device
 u32 sessionid = 0;             // session id for radius accounting
 int syslog_log = 0;            // are we logging to syslog
@@ -95,6 +95,7 @@ struct config_descriptt config_values[] = {
        CONFIG("debug", debug, INT),
        CONFIG("log_file", log_filename, STRING),
        CONFIG("pid_file", pid_file, STRING),
+       CONFIG("hostname", hostname, STRING),
        CONFIG("l2tp_secret", l2tpsecret, STRING),
        CONFIG("primary_dns", default_dns1, IP),
        CONFIG("secondary_dns", default_dns2, IP),
@@ -169,6 +170,7 @@ void dump_state();
 void tunnel_clean();
 tunnelidt new_tunnel();
 void update_config();
+int unhide_avp(u8 *avp, tunnelidt t, sessionidt s, u16 length);
 
 static void cache_ipmap(ipt ip, int s);
 static void uncache_ipmap(ipt ip);
@@ -1452,6 +1454,13 @@ void processudp(u8 * buf, int len, struct sockaddr_in *addr)
                                                continue;
                                        }
                                        log(4, ntohl(addr->sin_addr.s_addr), s, t, "Hidden AVP\n");
+                                       // Unhide the AVP
+                                       n = unhide_avp(b, t, s, n);
+                                       if (n == 0)
+                                       {
+                                               fatal = flags;
+                                               continue;
+                                       }
                                }
                                if (*b & 0x3C)
                                {
@@ -1566,6 +1575,11 @@ void processudp(u8 * buf, int len, struct sockaddr_in *addr)
                                                build_chap_response(b, 2, n, &chapresponse);
                                        }
                                        break;
+                               case 13:    // Response
+                                       // Why did they send a response? We never challenge.
+                                       log(2, ntohl(addr->sin_addr.s_addr), s, t, "   received unexpected challenge response\n");
+                               break;
+
                                case 14:    // assigned session
                                        asession = session[s].far = ntohs(*(u16 *) (b));
                                        log(4, ntohl(addr->sin_addr.s_addr), s, t, "   assigned session = %d\n", asession);
@@ -2448,6 +2462,7 @@ void mainloop(void)
 void initdata(void)
 {
        int i;
+       char *p;
 
        if ((_statistics = shared_malloc(sizeof(struct Tstats))) == MAP_FAILED)
        {
@@ -2534,13 +2549,11 @@ void initdata(void)
        for (i = 1; i < MAXTUNNEL- 1; i++)
                tunnel[i].state = TUNNELUNDEF;  // mark it as not filled in.
 
-       if (!*hostname)
-       {
-               char *p;
-               // Grab my hostname unless it's been specified
-               gethostname(hostname, sizeof(hostname));
-               if ((p = strchr(hostname, '.'))) *p = 0;
-       }
+       // Grab my hostname unless it's been specified
+       gethostname(config->hostname, sizeof(config->hostname));
+       if ((p = strchr(config->hostname, '.'))) *p = 0;
+       hostname = config->hostname;
+
        _statistics->start_time = _statistics->last_reset = time(NULL);
 
 #ifdef BGP
@@ -2854,7 +2867,7 @@ void dump_acct_info()
 
        for (i = 0; i < MAXSESSION; i++)
        {
-               if (!session[i].opened || !session[i].ip || !session[i].cin || !session[i].cout || !*session[i].user || session[i].walled_garden)
+               if (!session[i].opened || !session[i].ip || (!session[i].cin && !session[i].cout) || !*session[i].user || session[i].walled_garden)
                        continue;
                if (!f)
                {
@@ -2944,7 +2957,7 @@ int main(int argc, char *argv[])
        config->debug = optdebug;
 
        init_tbf();
-       init_cli(hostname);
+       init_cli();
        read_config_file();
 
        log(0, 0, 0, 0, "L2TPNS version " VERSION "\n");
@@ -4013,3 +4026,77 @@ int cmd_show_hist_open(struct cli_def *cli, char *command, char **argv, int argc
        cli_print(cli, "%d total sessions open.", count);
        return CLI_OK;
 }
+
+/* Unhide an avp.
+ *
+ * This unencodes the AVP using the L2TP CHAP secret and the
+ * previously stored random vector. It replaces the hidden data with
+ * the cleartext data and returns the length of the cleartext data
+ * (including the AVP "header" of 6 bytes).
+ *
+ * Based on code from rp-l2tpd by Roaring Penguin Software Inc.
+ */
+int unhide_avp(u8 *avp, tunnelidt t, sessionidt s, u16 length)
+{
+       MD5_CTX ctx;
+       u8 *cursor;
+       u8 digest[16];
+       u8 working_vector[16];
+       uint16_t hidden_length;
+       u8 type[2];
+       size_t done, todo;
+       u8 *output;
+
+       // Find the AVP type.
+       type[0] = *(avp + 4);
+       type[1] = *(avp + 5);
+
+       // Line up with the hidden data
+       cursor = output = avp + 6;
+
+       // Compute initial pad
+       MD5Init(&ctx);
+       MD5Update(&ctx, type, 2);
+       MD5Update(&ctx, config->l2tpsecret, strlen(config->l2tpsecret));
+       MD5Update(&ctx, session[s].random_vector, session[s].random_vector_length);
+       MD5Final(digest, &ctx);
+
+       // Get hidden length
+       hidden_length = ((uint16_t) (digest[0] ^ cursor[0])) * 256 + (uint16_t) (digest[1] ^ cursor[1]);
+
+       // Keep these for later use
+       working_vector[0] = *cursor;
+       working_vector[1] = *(cursor + 1);
+       cursor += 2;
+
+       if (hidden_length > length - 8)
+       {
+               log(1, 0, s, t, "Hidden length %d too long in AVP of length %d\n", (int) hidden_length, (int) length);
+               return 0;
+       }
+
+       /* Decrypt remainder */
+       done = 2;
+       todo = hidden_length;
+       while (todo)
+       {
+               working_vector[done] = *cursor;
+               *output = digest[done] ^ *cursor;
+               ++output;
+               ++cursor;
+               --todo;
+               ++done;
+               if (done == 16 && todo)
+               {
+                       // Compute new digest
+                       done = 0;
+                       MD5Init(&ctx);
+                       MD5Update(&ctx, config->l2tpsecret, strlen(config->l2tpsecret));
+                       MD5Update(&ctx, &working_vector, 16);
+                       MD5Final(digest, &ctx);
+               }
+       }
+
+       return hidden_length + 6;
+}
+