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don't shutdown on TerminateReq, wait for CDN
[l2tpns.git] / ppp.c
diff --git a/ppp.c b/ppp.c
index 17fde89..3e8bed9 100644 (file)
--- a/ppp.c
+++ b/ppp.c
@@ -1,6 +1,6 @@
 // L2TPNS PPP Stuff
 
 // L2TPNS PPP Stuff
 
-char const *cvs_id_ppp = "$Id: ppp.c,v 1.88 2005/12/07 05:21:37 bodea Exp $";
+char const *cvs_id_ppp = "$Id: ppp.c,v 1.99 2006/04/18 06:00:08 bodea Exp $";
 
 #include <stdio.h>
 #include <string.h>
 
 #include <stdio.h>
 #include <string.h>
@@ -40,7 +40,7 @@ void processpap(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
        {
                LOG(1, s, t, "Short PAP %u bytes\n", l);
                STAT(tunnel_rx_errors);
        {
                LOG(1, s, t, "Short PAP %u bytes\n", l);
                STAT(tunnel_rx_errors);
-               sessionshutdown(s, "Short PAP packet.", 3, 0);
+               sessionshutdown(s, "Short PAP packet.", CDN_ADMIN_DISC, TERM_USER_ERROR);
                return;
        }
 
                return;
        }
 
@@ -48,7 +48,7 @@ void processpap(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
        {
                LOG(1, s, t, "Length mismatch PAP %u/%u\n", hl, l);
                STAT(tunnel_rx_errors);
        {
                LOG(1, s, t, "Length mismatch PAP %u/%u\n", hl, l);
                STAT(tunnel_rx_errors);
-               sessionshutdown(s, "PAP length mismatch.", 3, 0);
+               sessionshutdown(s, "PAP length mismatch.", CDN_ADMIN_DISC, TERM_USER_ERROR);
                return;
        }
        l = hl;
                return;
        }
        l = hl;
@@ -57,7 +57,7 @@ void processpap(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
        {
                LOG(1, s, t, "Unexpected PAP code %d\n", *p);
                STAT(tunnel_rx_errors);
        {
                LOG(1, s, t, "Unexpected PAP code %d\n", *p);
                STAT(tunnel_rx_errors);
-               sessionshutdown(s, "Unexpected PAP code.", 3, 0);
+               sessionshutdown(s, "Unexpected PAP code.", CDN_ADMIN_DISC, TERM_USER_ERROR);
                return;
        }
 
                return;
        }
 
@@ -110,7 +110,7 @@ void processpap(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
                else
                {
                        LOG(1, s, t, "No RADIUS session available to authenticate session...\n");
                else
                {
                        LOG(1, s, t, "No RADIUS session available to authenticate session...\n");
-                       sessionshutdown(s, "No free RADIUS sessions.", 4, 0);
+                       sessionshutdown(s, "No free RADIUS sessions.", CDN_UNAVAILABLE, TERM_SERVICE_UNAVAILABLE);
                }
        }
        else
                }
        }
        else
@@ -152,7 +152,7 @@ void processchap(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
        {
                LOG(1, s, t, "Short CHAP %u bytes\n", l);
                STAT(tunnel_rx_errors);
        {
                LOG(1, s, t, "Short CHAP %u bytes\n", l);
                STAT(tunnel_rx_errors);
-               sessionshutdown(s, "Short CHAP packet.", 3, 0);
+               sessionshutdown(s, "Short CHAP packet.", CDN_ADMIN_DISC, TERM_USER_ERROR);
                return;
        }
 
                return;
        }
 
@@ -160,7 +160,7 @@ void processchap(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
        {
                LOG(1, s, t, "Length mismatch CHAP %u/%u\n", hl, l);
                STAT(tunnel_rx_errors);
        {
                LOG(1, s, t, "Length mismatch CHAP %u/%u\n", hl, l);
                STAT(tunnel_rx_errors);
-               sessionshutdown(s, "CHAP length mismatch.", 3, 0);
+               sessionshutdown(s, "CHAP length mismatch.", CDN_ADMIN_DISC, TERM_USER_ERROR);
                return;
        }
        l = hl;
                return;
        }
        l = hl;
@@ -169,7 +169,7 @@ void processchap(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
        {
                LOG(1, s, t, "Unexpected CHAP response code %d\n", *p);
                STAT(tunnel_rx_errors);
        {
                LOG(1, s, t, "Unexpected CHAP response code %d\n", *p);
                STAT(tunnel_rx_errors);
-               sessionshutdown(s, "CHAP length mismatch.", 3, 0);
+               sessionshutdown(s, "CHAP length mismatch.", CDN_ADMIN_DISC, TERM_USER_ERROR);
                return;
        }
 
                return;
        }
 
@@ -190,7 +190,7 @@ void processchap(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
        {
                LOG(1, s, t, "Wrong CHAP response ID %d (should be %d) (%d)\n", p[1], radius[r].id, r);
                STAT(tunnel_rx_errors);
        {
                LOG(1, s, t, "Wrong CHAP response ID %d (should be %d) (%d)\n", p[1], radius[r].id, r);
                STAT(tunnel_rx_errors);
-               sessionshutdown(s, "Unexpected CHAP response ID.", 3, 0);
+               sessionshutdown(s, "Unexpected CHAP response ID.", CDN_ADMIN_DISC, TERM_USER_ERROR);
                return;
        }
 
                return;
        }
 
@@ -198,7 +198,7 @@ void processchap(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
        {
                LOG(1, s, t, "Bad CHAP response length %d\n", l < 5 ? -1 : p[4]);
                STAT(tunnel_rx_errors);
        {
                LOG(1, s, t, "Bad CHAP response length %d\n", l < 5 ? -1 : p[4]);
                STAT(tunnel_rx_errors);
-               sessionshutdown(s, "Bad CHAP response length.", 3, 0);
+               sessionshutdown(s, "Bad CHAP response length.", CDN_ADMIN_DISC, TERM_USER_ERROR);
                return;
        }
 
                return;
        }
 
@@ -208,7 +208,7 @@ void processchap(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
        {
                LOG(1, s, t, "CHAP user too long %d\n", l - 16);
                STAT(tunnel_rx_errors);
        {
                LOG(1, s, t, "CHAP user too long %d\n", l - 16);
                STAT(tunnel_rx_errors);
-               sessionshutdown(s, "CHAP username too long.", 3, 0);
+               sessionshutdown(s, "CHAP username too long.", CDN_ADMIN_DISC, TERM_USER_ERROR);
                return;
        }
 
                return;
        }
 
@@ -475,7 +475,6 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 {
        uint8_t b[MAXETHER];
        uint8_t *q = NULL;
 {
        uint8_t b[MAXETHER];
        uint8_t *q = NULL;
-       uint32_t magicno = 0;
        uint16_t hl;
 
        CSTAT(processlcp);
        uint16_t hl;
 
        CSTAT(processlcp);
@@ -499,7 +498,9 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
        if (session[s].die) // going down...
                return;
 
        if (session[s].die) // going down...
                return;
 
-       LOG(*p == EchoReq ? 4 : 3, s, t, "LCP: recv %s\n", ppp_code(*p));
+       LOG((*p == EchoReq || *p == EchoReply) ? 4 : 3, s, t,
+               "LCP: recv %s\n", ppp_code(*p));
+
        if (config->debug > 3) dumplcp(p, l);
 
        if (*p == ConfigAck)
        if (config->debug > 3) dumplcp(p, l);
 
        if (*p == ConfigAck)
@@ -581,6 +582,7 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
                                                if (mru >= MINMTU)
                                                {
                                                        session[s].mru = mru;
                                                if (mru >= MINMTU)
                                                {
                                                        session[s].mru = mru;
+                                                       cluster_send_session(s);
                                                        break;
                                                }
 
                                                        break;
                                                }
 
@@ -647,11 +649,8 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
                                        }
                                        break;
 
                                        }
                                        break;
 
-                               case 5: // Magic-Number
-                                       magicno = ntohl(*(uint32_t *)(o + 2));
-                                       break;
-
                                case 4: // Quality-Protocol
                                case 4: // Quality-Protocol
+                               case 5: // Magic-Number
                                case 7: // Protocol-Field-Compression
                                case 8: // Address-And-Control-Field-Compression
                                        break;
                                case 7: // Protocol-Field-Compression
                                case 8: // Address-And-Control-Field-Compression
                                        break;
@@ -748,6 +747,7 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
                                case 1: // Maximum-Receive-Unit
                                        if (*p == ConfigNak)
                                        {
                                case 1: // Maximum-Receive-Unit
                                        if (*p == ConfigNak)
                                        {
+                                               if (length < 4) break;
                                                sess_local[s].ppp_mru = ntohs(*(uint16_t *)(o + 2));
                                                LOG(3, s, t, "    Remote requested MRU of %u\n", sess_local[s].ppp_mru);
                                        }
                                                sess_local[s].ppp_mru = ntohs(*(uint16_t *)(o + 2));
                                                LOG(3, s, t, "    Remote requested MRU of %u\n", sess_local[s].ppp_mru);
                                        }
@@ -765,14 +765,18 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 
                                        if (*p == ConfigNak)
                                        {
 
                                        if (*p == ConfigNak)
                                        {
-                                               int proto = ntohs(*(uint16_t *)(o + 2));
+                                               int proto;
+
+                                               if (length < 4) break;
+                                               proto = ntohs(*(uint16_t *)(o + 2));
+
                                                if (proto == PPPPAP)
                                                {
                                                        authtype = config->radius_authtypes & AUTHPAP;
                                                        LOG(3, s, t, "    Remote requested PAP authentication...%sing\n",
                                                                authtype ? "accept" : "reject");
                                                }
                                                if (proto == PPPPAP)
                                                {
                                                        authtype = config->radius_authtypes & AUTHPAP;
                                                        LOG(3, s, t, "    Remote requested PAP authentication...%sing\n",
                                                                authtype ? "accept" : "reject");
                                                }
-                                               else if (proto == PPPCHAP && *(o + 4) == 5)
+                                               else if (proto == PPPCHAP && length > 4 && *(o + 4) == 5)
                                                {
                                                        authtype = config->radius_authtypes & AUTHCHAP;
                                                        LOG(3, s, t, "    Remote requested CHAP authentication...%sing\n",
                                                {
                                                        authtype = config->radius_authtypes & AUTHCHAP;
                                                        LOG(3, s, t, "    Remote requested CHAP authentication...%sing\n",
@@ -792,9 +796,26 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 
                                        break;
 
 
                                        break;
 
+                               case 5: // Magic-Number
+                                       session[s].magic = 0;
+                                       if (*p == ConfigNak)
+                                       {
+                                               if (length < 6) break;
+                                               session[s].magic = ntohl(*(uint32_t *)(o + 2));
+                                       }
+
+                                       if (session[s].magic)
+                                               LOG(3, s, t, "    Remote requested magic-no %x\n", session[s].magic);
+                                       else
+                                               LOG(3, s, t, "    Remote rejected magic-no\n");
+
+                                       cluster_send_session(s);
+                                       break;
+
                                default:
                                        LOG(2, s, t, "LCP: remote sent %s for type %u?\n", ppp_code(*p), type);
                                default:
                                        LOG(2, s, t, "LCP: remote sent %s for type %u?\n", ppp_code(*p), type);
-                                       break;
+                                       sessionshutdown(s, "Unable to negotiate LCP.", CDN_ADMIN_DISC, TERM_USER_ERROR);
+                                       return;
                        }
                        x -= length;
                        o += length;
                        }
                        x -= length;
                        o += length;
@@ -802,7 +823,7 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 
                if (!authtype)
                {
 
                if (!authtype)
                {
-                       sessionshutdown(s, "Unsupported authentication.", 3, 0);
+                       sessionshutdown(s, "Unsupported authentication.", CDN_ADMIN_DISC, TERM_USER_ERROR);
                        return;
                }
 
                        return;
                }
 
@@ -849,7 +870,29 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
        }
        else if (*p == TerminateReq)
        {
        }
        else if (*p == TerminateReq)
        {
-               *p = TerminateAck;      // close
+               switch (session[s].ppp.lcp)
+               {
+               case Closed:
+               case Stopped:
+               case Closing:
+               case Stopping:
+               case RequestSent:
+               case AckReceived:
+               case AckSent:
+                       break;
+
+               case Opened:
+                       lcp_restart(s);
+                       zero_restart_count(s, lcp);
+                       change_state(s, lcp, Closing);
+                       break;
+
+               default:
+                       LOG(2, s, t, "LCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.lcp));
+                       return;
+               }
+
+               *p = TerminateAck;      // send ack
                q = makeppp(b, sizeof(b),  p, l, s, t, PPPLCP);
                if (!q) return;
 
                q = makeppp(b, sizeof(b),  p, l, s, t, PPPLCP);
                if (!q) return;
 
@@ -857,11 +900,6 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
                if (config->debug > 3) dumplcp(q, l);
 
                tunnelsend(b, l + (q - b), t); // send it
                if (config->debug > 3) dumplcp(q, l);
 
                tunnelsend(b, l + (q - b), t); // send it
-               sessionshutdown(s, "Remote end closed connection.", 3, 0);
-       }
-       else if (*p == TerminateAck)
-       {
-               sessionshutdown(s, "Connection closed.", 3, 0);
        }
        else if (*p == ProtocolRej)
        {
        }
        else if (*p == ProtocolRej)
        {
@@ -946,7 +984,7 @@ void processipcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
        CSTAT(processipcp);
 
        LOG_HEX(5, "IPCP", p, l);
        CSTAT(processipcp);
 
        LOG_HEX(5, "IPCP", p, l);
-       if (l < 5)
+       if (l < 4)
        {
                LOG(1, s, t, "Short IPCP %d bytes\n", l);
                STAT(tunnel_rx_errors);
        {
                LOG(1, s, t, "Short IPCP %d bytes\n", l);
                STAT(tunnel_rx_errors);
@@ -1003,11 +1041,13 @@ void processipcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 
                while (length > 2)
                {
 
                while (length > 2)
                {
+                       if (!o[1] || o[1] > length) return;
+
                        switch (*o)
                        {
                        case 3: // ip address
                                gotip++; // seen address
                        switch (*o)
                        {
                        case 3: // ip address
                                gotip++; // seen address
-                               if (o[1] != 6 || o[1] > length) return;
+                               if (o[1] != 6) return;
 
                                addr = htonl(session[s].ip);
                                if (memcmp(o + 2, &addr, (sizeof addr)))
 
                                addr = htonl(session[s].ip);
                                if (memcmp(o + 2, &addr, (sizeof addr)))
@@ -1016,7 +1056,7 @@ void processipcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
                                        q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
                                        if (!q || (q != oq && *response == ConfigRej))
                                        {
                                        q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
                                        if (!q || (q != oq && *response == ConfigRej))
                                        {
-                                               sessionshutdown(s, "Can't negotiate IPCP.", 3, 0);
+                                               sessionshutdown(s, "Can't negotiate IPCP.", CDN_ADMIN_DISC, TERM_USER_ERROR);
                                                return;
                                        }
                                }
                                                return;
                                        }
                                }
@@ -1024,7 +1064,7 @@ void processipcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
                                break;
 
                        case 129: // primary DNS
                                break;
 
                        case 129: // primary DNS
-                               if (o[1] != 6 || o[1] > length) return;
+                               if (o[1] != 6) return;
 
                                addr = htonl(session[s].dns1);
                                if (memcmp(o + 2, &addr, (sizeof addr)))
 
                                addr = htonl(session[s].dns1);
                                if (memcmp(o + 2, &addr, (sizeof addr)))
@@ -1036,7 +1076,7 @@ void processipcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
                                break;
 
                        case 131: // secondary DNS
                                break;
 
                        case 131: // secondary DNS
-                               if (o[1] != 6 || o[1] > length) return;
+                               if (o[1] != 6) return;
 
                                addr = htonl(session[s].dns2);
                                if (memcmp(o + 2, &addr, sizeof(addr)))
 
                                addr = htonl(session[s].dns2);
                                if (memcmp(o + 2, &addr, sizeof(addr)))
@@ -1130,12 +1170,33 @@ void processipcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
        }
        else if (*p == TerminateReq)
        {
        }
        else if (*p == TerminateReq)
        {
-               *p = TerminateAck;
-               q = makeppp(b, sizeof(b), p, l, s, t, PPPIPCP);
+               switch (session[s].ppp.ipcp)
+               {
+               case Closed:
+               case Stopped:
+               case Closing:
+               case Stopping:
+               case RequestSent:
+               case AckReceived:
+               case AckSent:
+                       break;
+
+               case Opened:
+                       zero_restart_count(s, ipcp);
+                       change_state(s, ipcp, Closing);
+                       break;
+
+               default:
+                       LOG(2, s, t, "IPCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipcp));
+                       return;
+               }
+
+               *p = TerminateAck;      // send ack
+               q = makeppp(b, sizeof(b),  p, l, s, t, PPPIPCP);
                if (!q) return;
                if (!q) return;
+
                LOG(3, s, t, "IPCP: send %s\n", ppp_code(*q));
                LOG(3, s, t, "IPCP: send %s\n", ppp_code(*q));
-               tunnelsend(b, l + (q - b), t);
-               change_state(s, ipcp, Stopped);
+               tunnelsend(b, l + (q - b), t); // send it
        }
        else if (*p != CodeRej)
        {
        }
        else if (*p != CodeRej)
        {
@@ -1228,11 +1289,13 @@ void processipv6cp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 
                while (length > 2)
                {
 
                while (length > 2)
                {
+                       if (!o[1] || o[1] > length) return;
+
                        switch (*o)
                        {
                        case 1: // interface identifier
                                gotip++; // seen address
                        switch (*o)
                        {
                        case 1: // interface identifier
                                gotip++; // seen address
-                               if (o[1] != 10 || o[1] > length) return;
+                               if (o[1] != 10) return;
 
                                *(uint32_t *) ident = htonl(session[s].ip);
                                *(uint32_t *) (ident + 4) = 0;
 
                                *(uint32_t *) ident = htonl(session[s].ip);
                                *(uint32_t *) (ident + 4) = 0;
@@ -1328,12 +1391,33 @@ void processipv6cp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
        }
        else if (*p == TerminateReq)
        {
        }
        else if (*p == TerminateReq)
        {
-               *p = TerminateAck;
+               switch (session[s].ppp.ipv6cp)
+               {
+               case Closed:
+               case Stopped:
+               case Closing:
+               case Stopping:
+               case RequestSent:
+               case AckReceived:
+               case AckSent:
+                       break;
+
+               case Opened:
+                       zero_restart_count(s, ipv6cp);
+                       change_state(s, ipv6cp, Closing);
+                       break;
+
+               default:
+                       LOG(2, s, t, "IPV6CP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipv6cp));
+                       return;
+               }
+
+               *p = TerminateAck;      // send ack
                q = makeppp(b, sizeof(b),  p, l, s, t, PPPIPV6CP);
                if (!q) return;
                q = makeppp(b, sizeof(b),  p, l, s, t, PPPIPV6CP);
                if (!q) return;
+
                LOG(3, s, t, "IPV6CP: send %s\n", ppp_code(*q));
                LOG(3, s, t, "IPV6CP: send %s\n", ppp_code(*q));
-               tunnelsend(b, l + (q - b), t);
-               change_state(s, ipv6cp, Stopped);
+               tunnelsend(b, l + (q - b), t); // send it
        }
        else if (*p != CodeRej)
        {
        }
        else if (*p != CodeRej)
        {
@@ -1732,7 +1816,7 @@ void sendchap(sessionidt s, tunnelidt t)
        radius[r].retry = backoff(radius[r].try++);
        if (radius[r].try > 5)
        {
        radius[r].retry = backoff(radius[r].try++);
        if (radius[r].try > 5)
        {
-               sessionshutdown(s, "CHAP timeout.", 3, 0);
+               sessionshutdown(s, "CHAP timeout.", CDN_ADMIN_DISC, TERM_REAUTHENTICATION_FAILURE);
                STAT(tunnel_tx_errors);
                return ;
        }
                STAT(tunnel_tx_errors);
                return ;
        }
@@ -1749,15 +1833,12 @@ void sendchap(sessionidt s, tunnelidt t)
 }
 
 // fill in a L2TP message with a PPP frame,
 }
 
 // fill in a L2TP message with a PPP frame,
-// copies existing PPP message and changes magic number if seen
 // returns start of PPP frame
 uint8_t *makeppp(uint8_t *b, int size, uint8_t *p, int l, sessionidt s, tunnelidt t, uint16_t mtype)
 {
        if (size < 12) // Need more space than this!!
        {
 // returns start of PPP frame
 uint8_t *makeppp(uint8_t *b, int size, uint8_t *p, int l, sessionidt s, tunnelidt t, uint16_t mtype)
 {
        if (size < 12) // Need more space than this!!
        {
-               static int backtrace_count = 0;
                LOG(0, s, t, "makeppp buffer too small for L2TP header (size=%d)\n", size);
                LOG(0, s, t, "makeppp buffer too small for L2TP header (size=%d)\n", size);
-               log_backtrace(backtrace_count, 5)
                return NULL;
        }
 
                return NULL;
        }
 
@@ -1780,9 +1861,7 @@ uint8_t *makeppp(uint8_t *b, int size, uint8_t *p, int l, sessionidt s, tunnelid
 
        if (l + 12 > size)
        {
 
        if (l + 12 > size)
        {
-               static int backtrace_count = 0;
                LOG(2, s, t, "makeppp would overflow buffer (size=%d, header+payload=%d)\n", size, l + 12);
                LOG(2, s, t, "makeppp would overflow buffer (size=%d, header+payload=%d)\n", size, l + 12);
-               log_backtrace(backtrace_count, 5)
                return NULL;
        }
 
                return NULL;
        }
 
@@ -1818,7 +1897,7 @@ static int add_lcp_auth(uint8_t *b, int size, int authtype)
        return len;
 }
 
        return len;
 }
 
-// Send initial LCP ConfigReq for MRU, authentication type and magic no
+// Send LCP ConfigReq for MRU, authentication type and magic no
 void sendlcp(sessionidt s, tunnelidt t)
 {
        uint8_t b[500], *q, *l;
 void sendlcp(sessionidt s, tunnelidt t)
 {
        uint8_t b[500], *q, *l;
@@ -1847,9 +1926,12 @@ void sendlcp(sessionidt s, tunnelidt t)
        if (authtype)
                l += add_lcp_auth(l, sizeof(b) - (l - b), authtype);
 
        if (authtype)
                l += add_lcp_auth(l, sizeof(b) - (l - b), authtype);
 
-       *l++ = 5; *l++ = 6; // Magic-Number (length 6)
-       *(uint32_t *) l = htonl(session[s].magic);
-       l += 4;
+       if (session[s].magic)
+       {
+               *l++ = 5; *l++ = 6; // Magic-Number (length 6)
+               *(uint32_t *) l = htonl(session[s].magic);
+               l += 4;
+       }
 
        *(uint16_t *)(q + 2) = htons(l - q); // Length
 
 
        *(uint16_t *)(q + 2) = htons(l - q); // Length
 
for cloning use: "git clone git://git.sameswireless.fr/l2tpns.git" ; For add to your sources.list: "deb http://package.sameswifi.fr/ jessie main"