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any traffic on a tunnel resets lastrec, not just control messages
[l2tpns.git] / ppp.c
diff --git a/ppp.c b/ppp.c
index de37bf2..806880e 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 1.9 2004-08-02 03:38:01 fred_nerk Exp $";
+char const *cvs_id_ppp = "$Id: ppp.c,v 1.79 2005-08-31 12:41:09 bodea Exp $";
 
 #include <stdio.h>
 #include <string.h>
 
 #include <stdio.h>
 #include <string.h>
@@ -19,88 +19,108 @@ extern sessiont *session;
 extern radiust *radius;
 extern int tunfd;
 extern char hostname[];
 extern radiust *radius;
 extern int tunfd;
 extern char hostname[];
-extern u32 eth_tx;
+extern uint32_t eth_tx;
 extern time_t time_now;
 extern time_t time_now;
-extern struct configt *config;
+extern configt *config;
+
+static int add_lcp_auth(uint8_t *b, int size, int authtype);
 
 // Process PAP messages
 
 // Process PAP messages
-void processpap(tunnelidt t, sessionidt s, u8 * p, u16 l)
+void processpap(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 {
 {
-       char user[129];
-       char pass[129];
-
+       char user[MAXUSER];
+       char pass[MAXPASS];
+       uint16_t hl;
+       uint16_t r;
 
 
-       CSTAT(call_processpap);
+       CSTAT(processpap);
 
 
-       log_hex(5, "PAP", p, l);
+       LOG_HEX(5, "PAP", p, l);
        if (l < 4)
        {
        if (l < 4)
        {
-               log(1, 0, s, t, "Short PAP %u bytes\n", l);
+               LOG(1, s, t, "Short PAP %u bytes\n", l);
                STAT(tunnel_rx_errors);
                STAT(tunnel_rx_errors);
-               return ;
+               sessionshutdown(s, "Short PAP packet.", 3, 0);
+               return;
        }
        }
-       if (*p != 1)
+
+       if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
        {
        {
-               log(1, 0, s, t, "Unexpected PAP code %d\n", *p);
+               LOG(1, s, t, "Length mismatch PAP %u/%u\n", hl, l);
                STAT(tunnel_rx_errors);
                STAT(tunnel_rx_errors);
-               return ;
+               sessionshutdown(s, "PAP length mismatch.", 3, 0);
+               return;
        }
        }
-       if (ntohs(*(u16 *) (p + 2)) > l)
+       l = hl;
+
+       if (*p != 1)
        {
        {
-               log(1, 0, s, t, "Length mismatch PAP %d/%d\n", ntohs(*(u16 *) (p + 2)), l);
+               LOG(1, s, t, "Unexpected PAP code %d\n", *p);
                STAT(tunnel_rx_errors);
                STAT(tunnel_rx_errors);
-               return ;
+               sessionshutdown(s, "Unexpected PAP code.", 3, 0);
+               return;
+       }
+
+       if (session[s].ppp.phase != Authenticate)
+       {
+               LOG(2, s, t, "PAP ignored in %s phase\n", ppp_phase(session[s].ppp.phase));
+               return;
        }
        }
+
        {
        {
-               u8 *b = p;
+               uint8_t *b = p;
                b += 4;
                b += 4;
+               user[0] = pass[0] = 0;
                if (*b && *b < sizeof(user))
                if (*b && *b < sizeof(user))
+               {
                        memcpy(user, b + 1, *b);
                        memcpy(user, b + 1, *b);
-               user[*b] = 0;
-               b += 1 + *b;
-               if (*b && *b < sizeof(pass))
-                       memcpy(pass, b + 1, *b);
-               pass[*b] = 0;
-               log(3, 0, s, t, "PAP login %s/%s\n", user, pass);
+                       user[*b] = 0;
+                       b += 1 + *b;
+                       if (*b && *b < sizeof(pass))
+                       {
+                               memcpy(pass, b + 1, *b);
+                               pass[*b] = 0;
+                       }
+               }
+               LOG(3, s, t, "PAP login %s/%s\n", user, pass);
        }
        }
-       if (session[s].ip || !session[s].radius)
+
+       if (session[s].ip || !(r = radiusnew(s)))
        {
                // respond now, either no RADIUS available or already authenticated
        {
                // respond now, either no RADIUS available or already authenticated
-               u8 b[MAXCONTROL];
-               u8 id = p[1];
-               u8 *p = makeppp(b, sizeof(b), 0, 0, t, s, PPPPAP);
-               if (!p) {       // Failed to make ppp header!
-                       log(1,0,0,0, "Failed to make PPP header in process pap!\n");
-                       return;
-               }
+               uint8_t b[MAXETHER];
+               uint8_t id = p[1];
+               uint8_t *p = makeppp(b, sizeof(b), 0, 0, s, t, PPPPAP);
+               if (!p) return;
+
                if (session[s].ip)
                if (session[s].ip)
-                       *p = 2;              // ACK
+                       *p = 2;                         // ACK
                else
                else
-                       *p = 3;              // cant authorise
+                       *p = 3;                         // cant authorise
                p[1] = id;
                p[1] = id;
-               *(u16 *) (p + 2) = htons(5); // length
-               p[4] = 0;               // no message
+               *(uint16_t *) (p + 2) = htons(5);       // length
+               p[4] = 0;                               // no message
+               tunnelsend(b, 5 + (p - b), t);          // send it
+
                if (session[s].ip)
                {
                if (session[s].ip)
                {
-                   log(3, session[s].ip, s, t, "%d Already an IP allocated: %s (%d)\n", getpid(), inet_toa(htonl(session[s].ip)), session[s].ip_pool_index);
+                       LOG(3, s, t, "Already an IP allocated: %s (%d)\n",
+                               fmtaddr(htonl(session[s].ip), 0), session[s].ip_pool_index);
                }
                else
                {
                }
                else
                {
-                   log(1, 0, s, t, "No radius session available to authenticate session...\n");
+                       LOG(1, s, t, "No RADIUS session available to authenticate session...\n");
+                       sessionshutdown(s, "No free RADIUS sessions.", 4, 0);
                }
                }
-               log(3, 0, s, t, "Fallback response to PAP (%s)\n", (session[s].ip) ? "ACK" : "NAK");
-               tunnelsend(b, 5 + (p - b), t); // send it
        }
        else
        }
        else
-       {                          // set up RADIUS request
-               u16 r = session[s].radius;
-
+       {
                // Run PRE_AUTH plugins
                struct param_pre_auth packet = { &tunnel[t], &session[s], strdup(user), strdup(pass), PPPPAP, 1 };
                run_plugins(PLUGIN_PRE_AUTH, &packet);
                if (!packet.continue_auth)
                {
                // Run PRE_AUTH plugins
                struct param_pre_auth packet = { &tunnel[t], &session[s], strdup(user), strdup(pass), PPPPAP, 1 };
                run_plugins(PLUGIN_PRE_AUTH, &packet);
                if (!packet.continue_auth)
                {
-                       log(3, 0, s, t, "A plugin rejected PRE_AUTH\n");
+                       LOG(3, s, t, "A plugin rejected PRE_AUTH\n");
                        if (packet.username) free(packet.username);
                        if (packet.password) free(packet.password);
                        return;
                        if (packet.username) free(packet.username);
                        if (packet.password) free(packet.password);
                        return;
@@ -113,76 +133,102 @@ void processpap(tunnelidt t, sessionidt s, u8 * p, u16 l)
                free(packet.password);
 
                radius[r].id = p[1];
                free(packet.password);
 
                radius[r].id = p[1];
-               log(3, 0, s, t, "Sending login for %s/%s to radius\n", user, pass);
+               LOG(3, s, t, "Sending login for %s/%s to RADIUS\n", user, pass);
                radiussend(r, RADIUSAUTH);
        }
 }
 
 // Process CHAP messages
                radiussend(r, RADIUSAUTH);
        }
 }
 
 // Process CHAP messages
-void processchap(tunnelidt t, sessionidt s, u8 * p, u16 l)
+void processchap(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 {
 {
-       u16 r;
-       u16 len;
+       uint16_t r;
+       uint16_t hl;
 
 
+       CSTAT(processchap);
 
 
-       CSTAT(call_processchap);
+       LOG_HEX(5, "CHAP", p, l);
 
 
-       log_hex(5, "CHAP", p, l);
-       r = session[s].radius;
-       if (!r)
+       if (l < 4)
        {
        {
-               log(1, 0, s, t, "Unexpected CHAP message\n");
-
-// FIXME: Need to drop the session here.
+               LOG(1, s, t, "Short CHAP %u bytes\n", l);
+               STAT(tunnel_rx_errors);
+               sessionshutdown(s, "Short CHAP packet.", 3, 0);
+               return;
+       }
 
 
+       if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
+       {
+               LOG(1, s, t, "Length mismatch CHAP %u/%u\n", hl, l);
                STAT(tunnel_rx_errors);
                STAT(tunnel_rx_errors);
+               sessionshutdown(s, "CHAP length mismatch.", 3, 0);
                return;
        }
                return;
        }
+       l = hl;
+
        if (*p != 2)
        {
        if (*p != 2)
        {
-               log(1, 0, s, t, "Unexpected CHAP response code %d\n", *p);
+               LOG(1, s, t, "Unexpected CHAP response code %d\n", *p);
                STAT(tunnel_rx_errors);
                STAT(tunnel_rx_errors);
+               sessionshutdown(s, "CHAP length mismatch.", 3, 0);
                return;
        }
                return;
        }
-       if (p[1] != radius[r].id)
+
+       r = sess_local[s].radius;
+       if (!r)
        {
        {
-               log(1, 0, s, t, "Wrong CHAP response ID %d (should be %d) (%d)\n", p[1], radius[r].id, r);
-               STAT(tunnel_rx_errors);
-               return ;
+               LOG(3, s, t, "Unexpected CHAP message\n");
+               return;
+       }
+
+       if (session[s].ppp.phase != Authenticate)
+       {
+               LOG(2, s, t, "CHAP ignored in %s phase\n", ppp_phase(session[s].ppp.phase));
+               return;
        }
        }
-       len = ntohs(*(u16 *) (p + 2));
-       if (len > l)
+
+       if (p[1] != radius[r].id)
        {
        {
-               log(1, 0, s, t, "Bad CHAP length %d\n", len);
+               LOG(1, s, t, "Wrong CHAP response ID %d (should be %d) (%d)\n", p[1], radius[r].id, r);
                STAT(tunnel_rx_errors);
                STAT(tunnel_rx_errors);
-               return ;
+               sessionshutdown(s, "Unexpected CHAP response ID.", 3, 0);
+               return;
        }
        }
-       if (p[4] != 16)
+
+       if (l < 5 || p[4] != 16)
        {
        {
-               log(1, 0, s, t, "Bad CHAP response length %d\n", p[4]);
+               LOG(1, s, t, "Bad CHAP response length %d\n", l < 5 ? -1 : p[4]);
                STAT(tunnel_rx_errors);
                STAT(tunnel_rx_errors);
-               return ;
+               sessionshutdown(s, "Bad CHAP response length.", 3, 0);
+               return;
        }
        }
-       if (len - 21 >= sizeof(session[s].user))
+
+       l -= 5;
+       p += 5;
+       if (l < 16 || l - 16 >= sizeof(session[s].user))
        {
        {
-               log(1, 0, s, t, "CHAP user too long %d\n", len - 21);
+               LOG(1, s, t, "CHAP user too long %d\n", l - 16);
                STAT(tunnel_rx_errors);
                STAT(tunnel_rx_errors);
-               return ;
+               sessionshutdown(s, "CHAP username too long.", 3, 0);
+               return;
        }
 
        // Run PRE_AUTH plugins
        {
                struct param_pre_auth packet = { &tunnel[t], &session[s], NULL, NULL, PPPCHAP, 1 };
 
        }
 
        // Run PRE_AUTH plugins
        {
                struct param_pre_auth packet = { &tunnel[t], &session[s], NULL, NULL, PPPCHAP, 1 };
 
-               packet.username = calloc(len-20, 1);
-               packet.password = calloc(16, 1);
-               memcpy(packet.username, p + 21, len - 21);
-               memcpy(packet.password, p + 5, 16);
+               packet.password = calloc(17, 1);
+               memcpy(packet.password, p, 16);
+
+               p += 16;
+               l -= 16;
+
+               packet.username = calloc(l + 1, 1);
+               memcpy(packet.username, p, l);
 
                run_plugins(PLUGIN_PRE_AUTH, &packet);
                if (!packet.continue_auth)
                {
 
                run_plugins(PLUGIN_PRE_AUTH, &packet);
                if (!packet.continue_auth)
                {
-                       log(3, 0, s, t, "A plugin rejected PRE_AUTH\n");
+                       LOG(3, s, t, "A plugin rejected PRE_AUTH\n");
                        if (packet.username) free(packet.username);
                        if (packet.password) free(packet.password);
                        return;
                        if (packet.username) free(packet.username);
                        if (packet.password) free(packet.password);
                        return;
@@ -196,33 +242,18 @@ void processchap(tunnelidt t, sessionidt s, u8 * p, u16 l)
        }
 
        radius[r].chap = 1;
        }
 
        radius[r].chap = 1;
-       log(3, 0, s, t, "CHAP login %s\n", session[s].user);
+       LOG(3, s, t, "CHAP login %s\n", session[s].user);
        radiussend(r, RADIUSAUTH);
 }
 
        radiussend(r, RADIUSAUTH);
 }
 
-char *ppp_lcp_types[] = {
-       NULL,
-       "ConfigReq",
-       "ConfigAck",
-       "ConfigNak",
-       "ConfigRej",
-       "TerminateReq",
-       "TerminateAck",
-       "CodeRej",
-       "ProtocolRej",
-       "EchoReq",
-       "EchoReply",
-       "DiscardRequest",
-};
-
-void dumplcp(u8 *p, int l)
+static void dumplcp(uint8_t *p, int l)
 {
 {
-       signed int x = l - 4;
-       u8 *o = (p + 4);
+       int x = l - 4;
+       uint8_t *o = (p + 4);
 
 
-       log_hex(5, "PPP LCP Packet", p, l);
-       log(4, 0, 0, 0, "PPP LCP Packet type %d (%s len %d)\n", *p, ppp_lcp_types[(int)*p], ntohs( ((u16 *) p)[1]) );
-       log(4, 0, 0, 0, "Length: %d\n", l);
+       LOG_HEX(5, "PPP LCP Packet", p, l);
+       LOG(4, 0, 0, "PPP LCP Packet type %d (%s len %d)\n", *p, ppp_code((int)*p), ntohs( ((uint16_t *) p)[1]) );
+       LOG(4, 0, 0, "Length: %d\n", l);
        if (*p != ConfigReq && *p != ConfigRej && *p != ConfigAck)
                return;
 
        if (*p != ConfigReq && *p != ConfigRej && *p != ConfigAck)
                return;
 
@@ -232,12 +263,12 @@ void dumplcp(u8 *p, int l)
                int length = o[1];
                if (length < 2)
                {
                int length = o[1];
                if (length < 2)
                {
-                       log(4, 0, 0, 0, "       Option length is %d...\n", length);
+                       LOG(4, 0, 0, "  Option length is %d...\n", length);
                        break;
                }
                if (type == 0)
                {
                        break;
                }
                if (type == 0)
                {
-                       log(4, 0, 0, 0, "       Option type is 0...\n");
+                       LOG(4, 0, 0, "  Option type is 0...\n");
                        x -= length;
                        o += length;
                        continue;
                        x -= length;
                        o += length;
                        continue;
@@ -246,52 +277,57 @@ void dumplcp(u8 *p, int l)
                {
                        case 1: // Maximum-Receive-Unit
                                if (length == 4)
                {
                        case 1: // Maximum-Receive-Unit
                                if (length == 4)
-                               log(4, 0, 0, 0, "    %s %d\n", lcp_types[type], ntohs(*(u16 *)(o + 2)));
+                                       LOG(4, 0, 0, "    %s %d\n", ppp_lcp_option(type), ntohs(*(uint16_t *)(o + 2)));
+                               else
+                                       LOG(4, 0, 0, "    %s odd length %d\n", ppp_lcp_option(type), length);
+                               break;
+                       case 2: // Async-Control-Character-Map
+                               if (length == 6)
+                               {
+                                       uint32_t asyncmap = ntohl(*(uint32_t *)(o + 2));
+                                       LOG(4, 0, 0, "    %s %x\n", ppp_lcp_option(type), asyncmap);
+                               }
                                else
                                else
-                                       log(4, 0, 0, 0, "    %s odd length %d\n", lcp_types[type], length);
+                                       LOG(4, 0, 0, "    %s odd length %d\n", ppp_lcp_option(type), length);
                                break;
                        case 3: // Authentication-Protocol
                                break;
                        case 3: // Authentication-Protocol
+                               if (length == 4)
                                {
                                {
-                                       if (length == 4)
-                                       {
-                                       int proto = ntohs(*(u16 *)(o + 2));
-                                               log(4, 0, 0, 0, "   %s 0x%x (%s)\n", lcp_types[type], proto,
-                                                       proto == 0xC223 ? "CHAP" :
-                                                       proto == 0xC023 ? "PAP"  : "UNKNOWN");
-                                       }
-                                       else
-                                               log(4, 0, 0, 0, "   %s odd length %d\n", lcp_types[type], length);
-                                       break;
+                                       int proto = ntohs(*(uint16_t *)(o + 2));
+                                       LOG(4, 0, 0, "    %s 0x%x (%s)\n", ppp_lcp_option(type), proto,
+                                               proto == PPPPAP  ? "PAP"  : "UNSUPPORTED");
+                               }
+                               else if (length == 5)
+                               {
+                                       int proto = ntohs(*(uint16_t *)(o + 2));
+                                       int algo = *(uint8_t *)(o + 4);
+                                       LOG(4, 0, 0, "    %s 0x%x 0x%x (%s)\n", ppp_lcp_option(type), proto, algo,
+                                               (proto == PPPCHAP && algo == 5) ? "CHAP MD5"  : "UNSUPPORTED");
                                }
                                }
+                               else
+                                       LOG(4, 0, 0, "    %s odd length %d\n", ppp_lcp_option(type), length);
+                               break;
                        case 4: // Quality-Protocol
                                {
                        case 4: // Quality-Protocol
                                {
-                                       u32 qp = ntohl(*(u32 *)(o + 2));
-                                       log(4, 0, 0, 0, "    %s %x\n", lcp_types[type], qp);
-                                       break;
+                                       uint32_t qp = ntohl(*(uint32_t *)(o + 2));
+                                       LOG(4, 0, 0, "    %s %x\n", ppp_lcp_option(type), qp);
                                }
                                }
+                               break;
                        case 5: // Magic-Number
                        case 5: // Magic-Number
+                               if (length == 6)
                                {
                                {
-                                       if (length == 6)
-                                       {
-                                       u32 magicno = ntohl(*(u32 *)(o + 2));
-                                       log(4, 0, 0, 0, "    %s %x\n", lcp_types[type], magicno);
-                                       }
-                                       else
-                                               log(4, 0, 0, 0, "   %s odd length %d\n", lcp_types[type], length);
-                                       break;
+                                       uint32_t magicno = ntohl(*(uint32_t *)(o + 2));
+                                       LOG(4, 0, 0, "    %s %x\n", ppp_lcp_option(type), magicno);
                                }
                                }
+                               else
+                                       LOG(4, 0, 0, "    %s odd length %d\n", ppp_lcp_option(type), length);
+                               break;
                        case 7: // Protocol-Field-Compression
                        case 7: // Protocol-Field-Compression
-                               {
-                                       log(4, 0, 0, 0, "    %s\n", lcp_types[type]);
-                                       break;
-                               }
                        case 8: // Address-And-Control-Field-Compression
                        case 8: // Address-And-Control-Field-Compression
-                               {
-                                       log(4, 0, 0, 0, "    %s\n", lcp_types[type]);
-                                       break;
-                               }
+                               LOG(4, 0, 0, "    %s\n", ppp_lcp_option(type));
+                               break;
                        default:
                        default:
-                               log(2, 0, 0, 0, "    Unknown PPP LCP Option type %d\n", type);
+                               LOG(2, 0, 0, "    Unknown PPP LCP Option type %d\n", type);
                                break;
                }
                x -= length;
                                break;
                }
                x -= length;
@@ -299,284 +335,1017 @@ void dumplcp(u8 *p, int l)
        }
 }
 
        }
 }
 
-// Process LCP messages
-void processlcp(tunnelidt t, sessionidt s, u8 * p, u16 l)
+void lcp_open(sessionidt s, tunnelidt t)
+{
+       // transition to Authentication or Network phase: 
+       session[s].ppp.phase = sess_local[s].lcp_authtype ? Authenticate : Network;
+
+       LOG(3, s, t, "LCP: Opened, phase %s\n", ppp_phase(session[s].ppp.phase));
+
+       // LCP now Opened
+       change_state(s, lcp, Opened);
+
+       if (session[s].ppp.phase == Authenticate)
+       {
+               if (sess_local[s].lcp_authtype == AUTHCHAP)
+                       sendchap(s, t);
+       }
+       else
+       {
+               // This-Layer-Up
+               sendipcp(s, t);
+               change_state(s, ipcp, RequestSent);
+               // move to passive state for IPv6 (if configured), CCP
+               if (config->ipv6_prefix.s6_addr[0])
+                       change_state(s, ipv6cp, Stopped);
+               else
+                       change_state(s, ipv6cp, Closed);
+
+               change_state(s, ccp, Stopped);
+       }
+}
+
+static void lcp_restart(sessionidt s)
+{
+       session[s].ppp.phase = Establish;
+       // This-Layer-Down
+       change_state(s, ipcp, Dead);
+       change_state(s, ipv6cp, Dead);
+       change_state(s, ccp, Dead);
+}
+
+static uint8_t *ppp_rej(sessionidt s, uint8_t *buf, size_t blen, uint16_t mtype,
+       uint8_t **response, uint8_t *queued, uint8_t *packet, uint8_t *option)
+{
+       if (!*response || **response != ConfigRej)
+       {
+               queued = *response = makeppp(buf, blen, packet, 2, s, session[s].tunnel, mtype);
+               if (!queued)
+                       return 0;
+
+               *queued = ConfigRej;
+               queued += 4;
+       }
+
+       if ((queued - buf + option[1]) > blen)
+       {
+               LOG(2, s, session[s].tunnel, "PPP overflow for ConfigRej (proto %u, option %u).\n", mtype, *option);
+               return 0;
+       }
+
+       memcpy(queued, option, option[1]);
+       return queued + option[1];
+}
+
+static uint8_t *ppp_nak(sessionidt s, uint8_t *buf, size_t blen, uint16_t mtype,
+       uint8_t **response, uint8_t *queued, uint8_t *packet, uint8_t *option,
+       uint8_t *value, size_t vlen)
 {
 {
-       u8 b[MAXCONTROL];
-       u8 *q = NULL;
+       int *nak_sent;
+       switch (mtype)
+       {
+       case PPPLCP:    nak_sent = &sess_local[s].lcp.nak_sent;    break;
+       case PPPIPCP:   nak_sent = &sess_local[s].ipcp.nak_sent;   break;
+       case PPPIPV6CP: nak_sent = &sess_local[s].ipv6cp.nak_sent; break;
+       default:        return 0; // ?
+       }
+
+       if (*response && **response != ConfigNak)
+       {
+               if (*nak_sent < config->ppp_max_failure) // reject queued
+                       return queued;
+
+               return ppp_rej(s, buf, blen, mtype, response, 0, packet, option);
+       }
+
+       if (!*response)
+       {
+               if (*nak_sent >= config->ppp_max_failure)
+                       return ppp_rej(s, buf, blen, mtype, response, 0, packet, option);
+
+               queued = *response = makeppp(buf, blen, packet, 2, s, session[s].tunnel, mtype);
+               if (!queued)
+                       return 0;
+
+               (*nak_sent)++;
+               *queued = ConfigNak;
+               queued += 4;
+       }
+
+       if ((queued - buf + vlen + 2) > blen)
+       {
+               LOG(2, s, session[s].tunnel, "PPP overflow for ConfigNak (proto %u, option %u).\n", mtype, *option);
+               return 0;
+       }
+
+       *queued++ = *option;
+       *queued++ = vlen + 2;
+       memcpy(queued, value, vlen);
+       return queued + vlen;
+}
 
 
+// Process LCP messages
+void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
+{
+       uint8_t b[MAXETHER];
+       uint8_t *q = NULL;
+       uint32_t magicno = 0;
+       uint16_t hl;
 
 
-       CSTAT(call_processlcp);
+       CSTAT(processlcp);
 
 
-       log_hex(5, "LCP", p, l);
+       LOG_HEX(5, "LCP", p, l);
        if (l < 4)
        {
        if (l < 4)
        {
-               log(1, session[s].ip, s, t, "Short LCP %d bytes\n", l);
+               LOG(1, s, t, "Short LCP %d bytes\n", l);
+               STAT(tunnel_rx_errors);
+               return ;
+       }
+
+       if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
+       {
+               LOG(1, s, t, "Length mismatch LCP %u/%u\n", hl, l);
                STAT(tunnel_rx_errors);
                return ;
        }
                STAT(tunnel_rx_errors);
                return ;
        }
+       l = hl;
+
+       if (session[s].die) // going down...
+               return;
+
+       LOG(*p == EchoReq ? 4 : 3, s, t, "LCP: recv %s\n", ppp_code(*p));
+       if (config->debug > 3) dumplcp(p, l);
+
        if (*p == ConfigAck)
        {
        if (*p == ConfigAck)
        {
-               log(3, session[s].ip, s, t, "LCP: Discarding ConfigAck\n");
-               session[s].flags |= SESSIONLCPACK;
+               int x = l - 4;
+               uint8_t *o = (p + 4);
+               int authtype = 0;
+
+               while (x > 2)
+               {
+                       int type = o[0];
+                       int length = o[1];
+
+                       if (length == 0 || type == 0 || x < length) break;
+                       switch (type)
+                       {
+                               case 3: // Authentication-Protocol
+                                       {
+                                               int proto = ntohs(*(uint16_t *)(o + 2));
+                                               if (proto == PPPPAP)
+                                                       authtype = AUTHPAP;
+                                               else if (proto == PPPCHAP && *(o + 4) == 5)
+                                                       authtype = AUTHCHAP;
+                                       }
+
+                                       break;
+                       }
+                       x -= length;
+                       o += length;
+               }
+
+               if (!session[s].ip && authtype)
+                       sess_local[s].lcp_authtype = authtype;
+
+               switch (session[s].ppp.lcp)
+               {
+               case RequestSent:
+                       initialise_restart_count(s, lcp);
+                       change_state(s, lcp, AckReceived);
+                       break;
+
+               case AckReceived:
+               case Opened:
+                       LOG(2, s, t, "LCP: ConfigAck in state %s?  Sending ConfigReq\n", ppp_state(session[s].ppp.lcp));
+                       if (session[s].ppp.lcp == Opened)
+                               lcp_restart(s);
+
+                       sendlcp(s, t);
+                       change_state(s, lcp, RequestSent);
+                       break;
+
+               case AckSent:
+                       lcp_open(s, t);
+                       break;
+
+               default:
+                       LOG(2, s, t, "LCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.lcp));
+               }
        }
        else if (*p == ConfigReq)
        {
        }
        else if (*p == ConfigReq)
        {
-               signed int x = l - 4;
-               u8 *o = (p + 4);
-
-               log(3, session[s].ip, s, t, "LCP: ConfigReq (%d bytes)...\n", l);
-               dumplcp(p, l);
+               int x = l - 4;
+               uint8_t *o = (p + 4);
+               uint8_t *response = 0;
+               static uint8_t asyncmap[4] = { 0, 0, 0, 0 }; // all zero
+               static uint8_t authproto[5];
 
                while (x > 2)
                {
                        int type = o[0];
                        int length = o[1];
 
                while (x > 2)
                {
                        int type = o[0];
                        int length = o[1];
-                       if (length == 0 || type == 0) break;
+
+                       if (length == 0 || type == 0 || x < length) break;
                        switch (type)
                        {
                                case 1: // Maximum-Receive-Unit
                        switch (type)
                        {
                                case 1: // Maximum-Receive-Unit
-                                       session[s].mru = ntohs(*(u16 *)(o + 2));
+                                       session[s].mru = ntohs(*(uint16_t *)(o + 2));
+                                       break;
+
+                               case 2: // Async-Control-Character-Map
+                                       if (!ntohl(*(uint32_t *)(o + 2))) // all bits zero is OK
+                                               break;
+
+                                       LOG(3, s, t, "    Remote requesting asyncmap.  Rejecting.\n");
+                                       q = ppp_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, asyncmap, sizeof(asyncmap));
                                        break;
                                        break;
+
                                case 3: // Authentication-Protocol
                                        {
                                case 3: // Authentication-Protocol
                                        {
-                                               int proto = ntohs(*(u16 *)(o + 2));
-                                               if (proto == 0xC223)
+                                               int proto = ntohs(*(uint16_t *)(o + 2));
+                                               char proto_name[] = "0x0000";
+                                               int alen;
+
+                                               if (proto == PPPPAP)
                                                {
                                                {
-                                                       log(2, session[s].ip, s, t, "    Remote end is trying to do CHAP. Rejecting it.\n");
+                                                       if (config->radius_authtypes & AUTHPAP)
+                                                       {
+                                                               sess_local[s].lcp_authtype = AUTHPAP;
+                                                               break;
+                                                       }
 
 
-                                                       if (!q)
+                                                       strcpy(proto_name, "PAP");
+                                               }
+                                               else if (proto == PPPCHAP)
+                                               {
+                                                       if (config->radius_authtypes & AUTHCHAP
+                                                           && *(o + 4) == 5) // MD5
                                                        {
                                                        {
-                                                               q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
-                                                               if (!q) {
-                                                                       log(2, session[s].ip, s, t, " Failed to send packet.\n");
-                                                                       break;
-                                                               }
-                                                               *q++ = ConfigNak;
+                                                               sess_local[s].lcp_authtype = AUTHCHAP;
+                                                               break;
                                                        }
                                                        }
-                                                       memcpy(q, o, length);
-                                                       *(u16 *)(q += 2) = htons(0xC023); // NAK -> Use PAP instead
-                                                       q += length;
+
+                                                       strcpy(proto_name, "CHAP");
+                                               }
+                                               else
+                                                       sprintf(proto_name, "%#4.4x", proto);
+
+                                               LOG(3, s, t, "    Remote requesting %s authentication.  Rejecting.\n", proto_name);
+
+                                               alen = add_lcp_auth(authproto, sizeof(authproto), config->radius_authprefer);
+                                               if (alen < 2) break; // paranoia
+
+                                               q = ppp_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, authproto + 2, alen - 2);
+                                               if (q && *response == ConfigNak &&
+                                                       config->radius_authtypes != config->radius_authprefer)
+                                               {
+                                                       // alternate type
+                                                       alen = add_lcp_auth(authproto, sizeof(authproto), config->radius_authtypes & ~config->radius_authprefer);
+                                                       if (alen < 2) break;
+                                                       q = ppp_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, authproto + 2, alen - 2);
                                                }
                                                }
+
                                                break;
                                        }
                                                break;
                                        }
+                                       break;
+
                                case 5: // Magic-Number
                                case 5: // Magic-Number
-                                       {
-//                                             u32 magicno = ntohl(*(u32 *)(o + 2));
-                                               break;
-                                       }
+                                       magicno = ntohl(*(uint32_t *)(o + 2));
+                                       break;
+
                                case 4: // Quality-Protocol
                                case 4: // Quality-Protocol
-                                       {
-//                                             u32 qp = ntohl(*(u32 *)(o + 2));
-                                               break;
-                                       }
                                case 7: // Protocol-Field-Compression
                                case 7: // Protocol-Field-Compression
-                                       {
-//                                             u32 pfc = ntohl(*(u32 *)(o + 2));
-                                               break;
-                                       }
                                case 8: // Address-And-Control-Field-Compression
                                case 8: // Address-And-Control-Field-Compression
-                                       {
-//                                             u32 afc = ntohl(*(u32 *)(o + 2));
-                                               break;
-                                       }
-                               default:
-                                       log(2, session[s].ip, s, t, "    Unknown PPP LCP Option type %d\n", type);
                                        break;
                                        break;
+
+                               default: // Reject any unknown options
+                                       LOG(3, s, t, "    Rejecting unknown PPP LCP option %d\n", type);
+                                       q = ppp_rej(s, b, sizeof(b), PPPLCP, &response, q, p, o);
                        }
                        x -= length;
                        o += length;
                }
 
                        }
                        x -= length;
                        o += length;
                }
 
-               if (!q)
+               if (response)
                {
                {
-                       // Send back a ConfigAck
-                       log(3, session[s].ip, s, t, "ConfigReq accepted, sending as Ack\n");
-                       q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
-                       if (!q) {
-                               log(3, session[s].ip, s, t, " failed to create packet.\n");
-                               return;
-                       }
-                       *q = ConfigAck;
-                       tunnelsend(b, l + (q - b), t);
+                       l = q - response; // LCP packet length
+                       *((uint16_t *) (response + 2)) = htons(l); // update header
                }
                else
                {
                }
                else
                {
-                       // Already built a ConfigNak... send it
-                       log(3, session[s].ip, s, t, "Sending ConfigNak\n");
-                       tunnelsend(b, l + (q - b), t);
+                       // Send packet back as ConfigAck
+                       response = makeppp(b, sizeof(b), p, l, s, t, PPPLCP);
+                       if (!response) return;
+                       *response = ConfigAck;
                }
 
                }
 
-               if (!(session[s].flags & SESSIONLCPACK))
-                       initlcp(t, s);
-       }
-       else if (*p == ConfigNak)
-       {
-               log(1, session[s].ip, s, t, "Remote end sent a ConfigNak. Ignoring\n");
-               dumplcp(p, l);
-               return ;
-       }
-       else if (*p == TerminateReq)
-       {
-               *p = TerminateAck;     // close
-               q = makeppp(b, sizeof(b),  p, l, t, s, PPPLCP);
-               if (!q) {
-                       log(3, session[s].ip, s, t, "Failed to create PPP packet in processlcp.\n");
-                       return;
-               }
-               log(3, session[s].ip, s, t, "LCP: Received TerminateReq. Sending TerminateAck\n");
-               sessionshutdown(s, "Remote end closed connection.");
-               tunnelsend(b, l + (q - b), t); // send it
-       }
-       else if (*p == TerminateAck)
-       {
-               sessionshutdown(s, "Connection closed.");
-       }
-       else if (*p == EchoReq)
-       {
-               *p = EchoReply;      // reply
-               *(u32 *) (p + 4) = htonl(session[s].magic); // our magic number
-               q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
-               if (!q) {
-                       log(3, session[s].ip, s, t, " failed to send EchoReply.\n");
+               switch (session[s].ppp.lcp)
+               {
+               case Closed:
+                       response = makeppp(b, sizeof(b), p, 2, s, t, PPPLCP);
+                       if (!response) return;
+                       *response = TerminateAck;
+                       *((uint16_t *) (response + 2)) = htons(l = 4);
+                       break;
+
+               case Stopped:
+                       initialise_restart_count(s, lcp);
+                       sendlcp(s, t);
+                       if (*response == ConfigAck)
+                               change_state(s, lcp, AckSent);
+                       else
+                               change_state(s, lcp, RequestSent);
+
+                       break;
+
+               case RequestSent:
+                       if (*response == ConfigAck)
+                               change_state(s, lcp, AckSent);
+
+                       break;
+
+               case AckReceived:
+                       if (*response == ConfigAck)
+                               lcp_open(s, t);
+
+                       break;
+
+               case Opened:
+                       lcp_restart(s);
+                       sendlcp(s, t);
+                       /* fallthrough */
+
+               case AckSent:
+                       if (*response == ConfigAck)
+                               change_state(s, lcp, AckSent);
+                       else
+                               change_state(s, lcp, RequestSent);
+
+                       break;
+
+               default:
+                       LOG(2, s, t, "LCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.lcp));
                        return;
                }
                        return;
                }
-               log(5, session[s].ip, s, t, "LCP: Received EchoReq. Sending EchoReply\n");
-               tunnelsend(b, l + (q - b), t); // send it
-       }
-       else if (*p == EchoReply)
-       {
-               // Ignore it, last_packet time is set earlier than this.
+
+               LOG(3, s, t, "LCP: send %s\n", ppp_code(*response));
+               if (config->debug > 3) dumplcp(response, l);
+
+               tunnelsend(b, l + (response - b), t);
        }
        }
-       else
+       else if (*p == ConfigNak || *p == ConfigRej)
        {
        {
-               log(1, session[s].ip, s, t, "Unexpected LCP code %d\n", *p);
-               STAT(tunnel_rx_errors);
-               return ;
-       }
-}
-
-// Process IPCP messages
-void processipcp(tunnelidt t, sessionidt s, u8 * p, u16 l)
-{
+               int x = l - 4;
+               uint8_t *o = (p + 4);
+               int authtype = -1;
 
 
-       CSTAT(call_processipcp);
+               while (x > 2)
+               {
+                       int type = o[0];
+                       int length = o[1];
+
+                       if (length == 0 || type == 0 || x < length) break;
+                       switch (type)
+                       {
+                               case 1: // Maximum-Receive-Unit
+                                       if (*p == ConfigNak)
+                                       {
+                                               session[s].mru = ntohs(*(uint16_t *)(o + 2));
+                                               LOG(3, s, t, "    Remote requested MRU of %u\n", session[s].mru);
+                                       }
+                                       else
+                                       {
+                                               session[s].mru = 0;
+                                               LOG(3, s, t, "    Remote rejected MRU negotiation\n");
+                                       }
+
+                                       break;
+
+                               case 3: // Authentication-Protocol
+                                       if (authtype > 0)
+                                               break;
+
+                                       if (*p == ConfigNak)
+                                       {
+                                               int 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");
+                                               }
+                                               else if (proto == PPPCHAP && *(o + 4) == 5)
+                                               {
+                                                       authtype = config->radius_authtypes & AUTHCHAP;
+                                                       LOG(3, s, t, "    Remote requested CHAP authentication...%sing\n",
+                                                               authtype ? "accept" : "reject");
+                                               }
+                                               else
+                                               {
+                                                       LOG(3, s, t, "    Rejecting unsupported authentication %#4x\n",
+                                                               proto);
+                                               }
+                                       }
+                                       else
+                                       {
+                                               LOG(2, s, t, "LCP: remote rejected auth negotiation\n");
+                                               authtype = 0; // shutdown
+                                       }
+
+                                       break;
+
+                               default:
+                                       LOG(2, s, t, "LCP: remote sent %s for type %u?\n", ppp_code(*p), type);
+                                       break;
+                       }
+                       x -= length;
+                       o += length;
+               }
+
+               if (!authtype)
+               {
+                       sessionshutdown(s, "Unsupported authentication.", 3, 0);
+                       return;
+               }
+
+               if (authtype > 0)
+                       sess_local[s].lcp_authtype = authtype;
+
+               switch (session[s].ppp.lcp)
+               {
+               case Closed:
+               case Stopped:
+                       {
+                               uint8_t *response = makeppp(b, sizeof(b), p, 2, s, t, PPPLCP);
+                               if (!response) return;
+                               *response = TerminateAck;
+                               *((uint16_t *) (response + 2)) = htons(l = 4);
+
+                               LOG(3, s, t, "LCP: send %s\n", ppp_code(*response));
+                               if (config->debug > 3) dumplcp(response, l);
+
+                               tunnelsend(b, l + (response - b), t);
+                       }
+                       break;
+
+               case RequestSent:
+               case AckSent:
+                       initialise_restart_count(s, lcp);
+                       sendlcp(s, t);
+                       break;
+
+               case AckReceived:
+                       LOG(2, s, t, "LCP: ConfigNak in state %s?  Sending ConfigReq\n", ppp_state(session[s].ppp.lcp));
+                       sendlcp(s, t);
+                       break;
+
+               case Opened:
+                       lcp_restart(s);
+                       sendlcp(s, t);
+                       break;
+
+               default:
+                       LOG(2, s, t, "LCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.lcp));
+                       return;
+               }
+       }
+       else if (*p == TerminateReq)
+       {
+               *p = TerminateAck;      // close
+               q = makeppp(b, sizeof(b),  p, l, s, t, PPPLCP);
+               if (!q) return;
 
 
-       log_hex(5, "IPCP", p, l);
+               LOG(3, s, t, "LCP: send %s\n", ppp_code(*q));
+               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)
+       {
+               uint16_t proto = 0;
+
+               if (l > 4)
+               {
+                       proto = *(p+4);
+                       if (l > 5 && !(proto & 1))
+                       {
+                               proto <<= 8;
+                               proto |= *(p+5);
+                       }
+               }
+
+               if (proto == PPPIPV6CP)
+               {
+                       LOG(3, s, t, "IPv6 rejected\n");
+                       change_state(s, ipv6cp, Closed);
+               }
+               else
+               {
+                       LOG(3, s, t, "LCP protocol reject: 0x%04X\n", proto);
+               }
+       }
+       else if (*p == EchoReq)
+       {
+               *p = EchoReply;         // reply
+               *(uint32_t *) (p + 4) = htonl(session[s].magic); // our magic number
+               q = makeppp(b, sizeof(b), p, l, s, t, PPPLCP);
+               if (!q) return;
+
+               LOG(4, s, t, "LCP: send %s\n", ppp_code(*q));
+               if (config->debug > 3) dumplcp(q, l);
+
+               tunnelsend(b, l + (q - b), t); // send it
+       }
+       else if (*p == EchoReply)
+       {
+               // Ignore it, last_packet time is set earlier than this.
+       }
+       else if (*p != CodeRej)
+       {
+               int code = *p;
+               int mru = session[s].mru;
+               if (!mru)
+                       mru = DEFAULT_MRU;
+
+               if (l > mru) l = mru;
+
+               *p = CodeRej;
+               q = makeppp(b, sizeof(b), p, l, s, t, PPPLCP);
+               if (!q) return;
+
+               LOG(2, s, t, "Unexpected LCP code %s\n", ppp_code(code));
+               LOG(3, s, t, "LCP: send %s\n", ppp_code(*q));
+               if (config->debug > 3) dumplcp(q, l);
+
+               tunnelsend(b, l + (q - b), t);
+       }
+}
+
+static void ipcp_open(sessionidt s, tunnelidt t)
+{
+       LOG(3, s, t, "IPCP: Opened, session is now active\n");
+
+       change_state(s, ipcp, Opened);
+
+       if (!session[s].walled_garden)
+       {
+               uint16_t r = radiusnew(s);
+               if (r)
+                       radiussend(r, RADIUSSTART); // send radius start
+       }
+
+       // start IPv6 if configured and still in passive state
+       if (session[s].ppp.ipv6cp == Stopped)
+       {
+               sendipv6cp(s, t);
+               change_state(s, ipv6cp, RequestSent);
+       }
+}
+
+// Process IPCP messages
+void processipcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
+{
+       uint8_t b[MAXETHER];
+       uint8_t *q = 0;
+       uint16_t hl;
+
+       CSTAT(processipcp);
+
+       LOG_HEX(5, "IPCP", p, l);
        if (l < 5)
        {
        if (l < 5)
        {
-               log(1, 0, s, t, "Short IPCP %d bytes\n", l);
+               LOG(1, s, t, "Short IPCP %d bytes\n", l);
+               STAT(tunnel_rx_errors);
+               return ;
+       }
+
+       if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
+       {
+               LOG(1, s, t, "Length mismatch IPCP %u/%u\n", hl, l);
                STAT(tunnel_rx_errors);
                return ;
        }
                STAT(tunnel_rx_errors);
                return ;
        }
+       l = hl;
+
+       if (session[s].ppp.phase < Network)
+       {
+               LOG(2, s, t, "IPCP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
+               return;
+       }
+
+       LOG(3, s, t, "IPCP: recv %s\n", ppp_code(*p));
+
        if (*p == ConfigAck)
        if (*p == ConfigAck)
-       {                          // happy with our IPCP
-               u16 r = session[s].radius;
-               if ((!r || radius[r].state == RADIUSIPCP) && !session[s].walled_garden) {
-                       if (!r)
-                               r = radiusnew(s);
-                       if (r)
-                               radiussend(r, RADIUSSTART); // send radius start, having got IPCP at last
+       {
+               switch (session[s].ppp.ipcp)
+               {
+               case RequestSent:
+                       initialise_restart_count(s, ipcp);
+                       change_state(s, ipcp, AckReceived);
+                       break;
+
+               case AckReceived:
+               case Opened:
+                       LOG(2, s, t, "IPCP: ConfigAck in state %s?  Sending ConfigReq\n", ppp_state(session[s].ppp.ipcp));
+                       sendipcp(s, t);
+                       change_state(s, ipcp, RequestSent);
+                       break;
+
+               case AckSent:
+                       ipcp_open(s, t);
+                       break;
+
+               default:
+                       LOG(2, s, t, "IPCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipcp));
+               }
+       }
+       else if (*p == ConfigReq)
+       {
+               uint8_t *response = 0;
+               uint8_t *o = p + 4;
+               int length = l - 4;
+               int gotip = 0;
+               in_addr_t addr;
+
+               while (length > 2)
+               {
+                       switch (*o)
+                       {
+                       case 3: // ip address
+                               gotip++; // seen address
+                               if (o[1] != 6 || o[1] > length) return;
+
+                               addr = htonl(session[s].ip);
+                               if (memcmp(o + 2, &addr, (sizeof addr)))
+                               {
+                                       uint8_t *oq = q;
+                                       q = ppp_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);
+                                               return;
+                                       }
+                               }
+
+                               break;
+
+                       case 129: // primary DNS
+                               if (o[1] != 6 || o[1] > length) return;
+
+                               addr = htonl(session[s].dns1);
+                               if (memcmp(o + 2, &addr, (sizeof addr)))
+                               {
+                                       q = ppp_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
+                                       if (!q) return;
+                               }
+
+                               break;
+
+                       case 131: // secondary DNS
+                               if (o[1] != 6 || o[1] > length) return;
+
+                               addr = htonl(session[s].dns1);
+                               if (memcmp(o + 2, &addr, sizeof(addr)))
+                               {
+                                       q = ppp_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
+                                       if (!q) return;
+                               }
+
+                               break;
+
+                       default:
+                               LOG(2, s, t, "    Rejecting PPP IPCP Option type %d\n", *o);
+                               q = ppp_rej(s, b, sizeof(b), PPPIPCP, &response, q, p, o);
+                               if (!q) return;
+                       }
+
+                       length -= o[1];
+                       o += o[1];
+               }
+
+               if (response)
+               {
+                       l = q - response; // IPCP packet length
+                       *((uint16_t *) (response + 2)) = htons(l); // update header
+               }
+               else if (gotip)
+               {
+                       // Send packet back as ConfigAck
+                       response = makeppp(b, sizeof(b), p, l, s, t, PPPIPCP);
+                       if (!response) return;
+                       *response = ConfigAck;
+               }
+               else
+               {
+                       LOG(1, s, t, "No IP in IPCP request\n");
+                       STAT(tunnel_rx_errors);
+                       return;
+               }
+
+               switch (session[s].ppp.ipcp)
+               {
+               case Closed:
+                       response = makeppp(b, sizeof(b), p, 2, s, t, PPPIPCP);
+                       if (!response) return;
+                       *response = TerminateAck;
+                       *((uint16_t *) (response + 2)) = htons(l = 4);
+                       break;
+
+               case Stopped:
+                       initialise_restart_count(s, ipcp);
+                       sendipcp(s, t);
+                       if (*response == ConfigAck)
+                               change_state(s, ipcp, AckSent);
+                       else
+                               change_state(s, ipcp, RequestSent);
+
+                       break;
+
+               case RequestSent:
+                       if (*response == ConfigAck)
+                               change_state(s, ipcp, AckSent);
+
+                       break;
+
+               case AckReceived:
+                       if (*response == ConfigAck)
+                               ipcp_open(s, t);
+
+                       break;
+
+               case Opened:
+                       initialise_restart_count(s, ipcp);
+                       sendipcp(s, t);
+                       /* fallthrough */
+
+               case AckSent:
+                       if (*response == ConfigAck)
+                               change_state(s, ipcp, AckSent);
+                       else
+                               change_state(s, ipcp, RequestSent);
+
+                       break;
+
+               default:
+                       LOG(2, s, t, "IPCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipcp));
+                       return;
                }
                }
-               session[s].flags |= SF_IPCP_ACKED;
 
 
-               return ;                 // done
+               LOG(3, s, t, "IPCP: send %s\n", ppp_code(*response));
+               tunnelsend(b, l + (response - b), t);
+       }
+       else if (*p == TerminateReq)
+       {
+               *p = TerminateAck;
+               q = makeppp(b, sizeof(b), p, l, s, t, PPPIPCP);
+               if (!q) return;
+               LOG(3, s, t, "IPCP: send %s\n", ppp_code(*q));
+               tunnelsend(b, l + (q - b), t);
+               change_state(s, ipcp, Stopped);
        }
        }
-       if (*p != ConfigReq)
+       else if (*p != CodeRej)
        {
        {
-               log(1, 0, s, t, "Unexpected IPCP code %d\n", *p);
+               int code = *p;
+               int mru = session[s].mru;
+               if (!mru)
+                       mru = DEFAULT_MRU;
+
+               if (l > mru) l = mru;
+
+               *p = CodeRej;
+               q = makeppp(b, sizeof(b), p, l, s, t, PPPIPCP);
+               if (!q) return;
+
+               LOG(2, s, t, "Unexpected IPCP code %s\n", ppp_code(code));
+               LOG(3, s, t, "IPCP: send %s\n", ppp_code(*q));
+               tunnelsend(b, l + (q - b), t);
+       }
+}
+
+static void ipv6cp_open(sessionidt s, tunnelidt t)
+{
+       LOG(3, s, t, "IPV6CP: Opened\n");
+
+       change_state(s, ipv6cp, Opened);
+       if (session[s].ipv6prefixlen)
+               route6set(s, session[s].ipv6route, session[s].ipv6prefixlen, 1);
+
+       // Send an initial RA (TODO: Should we send these regularly?)
+       send_ipv6_ra(s, t, NULL);
+}
+
+// Process IPV6CP messages
+void processipv6cp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
+{
+       uint8_t b[MAXETHER];
+       uint8_t *q = 0;
+       uint16_t hl;
+
+       CSTAT(processipv6cp);
+
+       LOG_HEX(5, "IPV6CP", p, l);
+       if (l < 4)
+       {
+               LOG(1, s, t, "Short IPV6CP %d bytes\n", l);
                STAT(tunnel_rx_errors);
                return ;
        }
                STAT(tunnel_rx_errors);
                return ;
        }
-       if (ntohs(*(u16 *) (p + 2)) > l)
+
+       if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
        {
        {
-               log(1, 0, s, t, "Length mismatch IPCP %d/%d\n", ntohs(*(u16 *) (p + 2)), l);
+               LOG(1, s, t, "Length mismatch IPV6CP %u/%u\n", hl, l);
                STAT(tunnel_rx_errors);
                return ;
        }
                STAT(tunnel_rx_errors);
                return ;
        }
+       l = hl;
+
+       if (session[s].ppp.phase < Network)
+       {
+               LOG(2, s, t, "IPV6CP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
+               return;
+       }
+
+       LOG(3, s, t, "IPV6CP: recv %s\n", ppp_code(*p));
+
+       if (!config->ipv6_prefix.s6_addr[0])
+       {
+               LOG(2, s, t, "IPV6CP: %s rejected (not configured)\n", ppp_code(*p));
+               *p = ProtocolRej;
+               q = makeppp(b, sizeof(b),  p, l, s, t, PPPIPV6CP);
+               if (!q) return;
+               tunnelsend(b, l + (q - b), t);
+               return;
+       }
+
        if (!session[s].ip)
        {
        if (!session[s].ip)
        {
-               log(3, 0, s, t, "Waiting on radius reply\n");
-               return ;                   // have to wait on RADIUS reply
+               LOG(3, s, t, "IPV6CP: no IPv4 address (IPCP in state %s)\n", ppp_state(session[s].ppp.ipcp));
+               return; // need IPCP to complete...
        }
        }
-       // form a config reply quoting the IP in the session
+
+       if (*p == ConfigAck)
        {
        {
-               u8 b[MAXCONTROL];
-               u8 *i,
-               *q;
+               switch (session[s].ppp.ipv6cp)
+               {
+               case RequestSent:
+                       initialise_restart_count(s, ipv6cp);
+                       change_state(s, ipv6cp, AckReceived);
+                       break;
+
+               case AckReceived:
+               case Opened:
+                       LOG(2, s, t, "IPV6CP: ConfigAck in state %s?  Sending ConfigReq\n", ppp_state(session[s].ppp.ipv6cp));
+                       sendipv6cp(s, t);
+                       change_state(s, ipv6cp, RequestSent);
+                       break;
+
+               case AckSent:
+                       ipv6cp_open(s, t);
+                       break;
+
+               default:
+                       LOG(2, s, t, "IPV6CP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipv6cp));
+               }
+       }
+       else if (*p == ConfigReq)
+       {
+               uint8_t *response = 0;
+               uint8_t *o = p + 4;
+               int length = l - 4;
+               int gotip = 0;
+               uint8_t ident[8];
 
 
-               q = p + 4;
-               i = p + l;
-               while (q < i && q[1])
+               while (length > 2)
                {
                {
-                       if (*q != 0x81 && *q != 0x83 && *q != 3)
-                               break;
-                       q += q[1];
-               }
-               if (q < i)
-               {                       // reject
-                       u16 n = 4;
-                       i = p + l;
-                       q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP);
-                       if (!q) {
-                               log(2, 0, s, t, "Failed to send IPCP.\n");
-                               return;
-                       }
-                       *q = ConfigRej;
-                       p += 4;
-                       while (p < i && p[1])
+                       switch (*o)
                        {
                        {
-                               if (*p != 0x81 && *p != 0x83 && *p != 3)
+                       case 1: // interface identifier
+                               gotip++; // seen address
+                               if (o[1] != 10 || o[1] > length) return;
+
+                               *(uint32_t *) ident = htonl(session[s].ip);
+                               *(uint32_t *) (ident + 4) = 0;
+
+                               if (memcmp(o + 2, ident, sizeof(ident)))
                                {
                                {
-                                       log(2, 0, s, t, "IPCP reject %d\n", *p);
-                                       memcpy(q + n, p, p[1]);
-                                       n += p[1];
+                                       q = ppp_nak(s, b, sizeof(b), PPPIPV6CP, &response, q, p, o, ident, sizeof(ident));
+                                       if (!q) return;
                                }
                                }
-                               p += p[1];
+
+                               break;
+
+                       default:
+                               LOG(2, s, t, "    Rejecting PPP IPV6CP Option type %d\n", *o);
+                               q = ppp_rej(s, b, sizeof(b), PPPIPV6CP, &response, q, p, o);
+                               if (!q) return;
                        }
                        }
-                       *(u16 *) (q + 2) = htons(n);
-                       tunnelsend(b, n + (q - b), t); // send it
+
+                       length -= o[1];
+                       o += o[1];
+               }
+
+               if (response)
+               {
+                       l = q - response; // IPV6CP packet length
+                       *((uint16_t *) (response + 2)) = htons(l); // update header
+               }
+               else if (gotip)
+               {
+                       // Send packet back as ConfigAck
+                       response = makeppp(b, sizeof(b), p, l, s, t, PPPIPV6CP);
+                       if (!response) return;
+                       *response = ConfigAck;
                }
                else
                {
                }
                else
                {
-                       *p = ConfigAck;
-                       i = findppp(p, 0x81); // Primary DNS address
-                       if (i)
-                       {
-                               if (*(u32 *) (i + 2) != htonl(session[s].dns1))
-                               {
-                                       *(u32 *) (i + 2) = htonl(session[s].dns1);
-                                       *p = ConfigNak;
-                               }
-                       }
-                       i = findppp(p, 0x83); // Secondary DNS address (TBA, is it)
-                       if (i)
-                       {
-                               if (*(u32 *) (i + 2) != htonl(session[s].dns2))
-                               {
-                                       *(u32 *) (i + 2) = htonl(session[s].dns2);
-                                       *p = ConfigNak;
-                               }
-                       }
-                       i = findppp(p, 3);   // IP address
-                       if (!i || i[1] != 6)
-                       {
-                               log(1, 0, s, t, "No IP in IPCP request\n");
-                               STAT(tunnel_rx_errors);
-                               return ;
-                       }
-                       if (*(u32 *) (i + 2) != htonl(session[s].ip))
-                       {
-                               *(u32 *) (i + 2) = htonl(session[s].ip);
-                               *p = ConfigNak;
-                       }
-                       q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP);
-                       if (!q) {
-                               log(2, 0, s, t, " Failed to send IPCP packet.\n");
-                               return;
-                       }
-                       tunnelsend(b, l + (q - b), t); // send it
+                       LOG(1, s, t, "No interface identifier in IPV6CP request\n");
+                       STAT(tunnel_rx_errors);
+                       return;
                }
                }
+
+               switch (session[s].ppp.ipv6cp)
+               {
+               case Closed:
+                       response = makeppp(b, sizeof(b), p, 2, s, t, PPPIPV6CP);
+                       if (!response) return;
+                       *response = TerminateAck;
+                       *((uint16_t *) (response + 2)) = htons(l = 4);
+                       break;
+
+               case Stopped:
+                       initialise_restart_count(s, ipv6cp);
+                       sendipv6cp(s, t);
+                       if (*response == ConfigAck)
+                               change_state(s, ipv6cp, AckSent);
+                       else
+                               change_state(s, ipv6cp, RequestSent);
+
+                       break;
+
+               case RequestSent:
+                       if (*response == ConfigAck)
+                               change_state(s, ipv6cp, AckSent);
+
+                       break;
+
+               case AckReceived:
+                       if (*response == ConfigAck)
+                               ipv6cp_open(s, t);
+
+                       break;
+
+               case Opened:
+                       initialise_restart_count(s, ipv6cp);
+                       sendipv6cp(s, t);
+                       /* fallthrough */
+
+               case AckSent:
+                       if (*response == ConfigAck)
+                               change_state(s, ipv6cp, AckSent);
+                       else
+                               change_state(s, ipv6cp, RequestSent);
+
+                       break;
+
+               default:
+                       LOG(2, s, t, "IPV6CP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipv6cp));
+                       return;
+               }
+
+               LOG(3, s, t, "IPV6CP: send %s\n", ppp_code(*response));
+               tunnelsend(b, l + (response - b), t);
+       }
+       else if (*p == TerminateReq)
+       {
+               *p = TerminateAck;
+               q = makeppp(b, sizeof(b),  p, l, s, t, PPPIPV6CP);
+               if (!q) return;
+               LOG(3, s, t, "IPV6CP: send %s\n", ppp_code(*q));
+               tunnelsend(b, l + (q - b), t);
+               change_state(s, ipv6cp, Stopped);
+       }
+       else if (*p != CodeRej)
+       {
+               int code = *p;
+               int mru = session[s].mru;
+               if (!mru)
+                       mru = DEFAULT_MRU;
+
+               if (l > mru) l = mru;
+
+               *p = CodeRej;
+               q = makeppp(b, sizeof(b), p, l, s, t, PPPIPV6CP);
+               if (!q) return;
+
+               LOG(2, s, t, "Unexpected IPV6CP code %s\n", ppp_code(code));
+               LOG(3, s, t, "IPV6CP: send %s\n", ppp_code(*q));
+               tunnelsend(b, l + (q - b), t);
        }
 }
 
        }
 }
 
@@ -584,57 +1353,148 @@ void processipcp(tunnelidt t, sessionidt s, u8 * p, u16 l)
 //
 // This MUST be called with at least 4 byte behind 'p'.
 // (i.e. this routine writes to p[-4]).
 //
 // This MUST be called with at least 4 byte behind 'p'.
 // (i.e. this routine writes to p[-4]).
-void processipin(tunnelidt t, sessionidt s, u8 * p, u16 l)
+void processipin(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 {
 {
-       ipt ip;
-
+       in_addr_t ip;
 
 
-       CSTAT(call_processipin);
+       CSTAT(processipin);
 
 
-       log_hex(5, "IP", p, l);
+       LOG_HEX(5, "IP", p, l);
 
 
-       ip = ntohl(*(u32 *)(p + 12));
+       ip = ntohl(*(uint32_t *)(p + 12));
 
        if (l > MAXETHER)
        {
 
        if (l > MAXETHER)
        {
-               log(1, ip, s, t, "IP packet too long %d\n", l);
+               LOG(1, s, t, "IP packet too long %d\n", l);
                STAT(tunnel_rx_errors);
                return ;
        }
 
                STAT(tunnel_rx_errors);
                return ;
        }
 
+       if (session[s].ppp.phase != Network || session[s].ppp.ipcp != Opened)
+               return;
+
        // no spoof (do sessionbyip to handled statically routed subnets)
        if (ip != session[s].ip && sessionbyip(htonl(ip)) != s)
        {
        // no spoof (do sessionbyip to handled statically routed subnets)
        if (ip != session[s].ip && sessionbyip(htonl(ip)) != s)
        {
-               log(5, ip, s, t, "Dropping packet with spoofed IP %s\n", inet_toa(htonl(ip)));
+               LOG(5, s, t, "Dropping packet with spoofed IP %s\n", fmtaddr(htonl(ip), 0));
                return;
        }
 
                return;
        }
 
+       // run access-list if any
+       if (session[s].filter_in && !ip_filter(p, l, session[s].filter_in - 1))
+               return;
+
        // Add on the tun header
        p -= 4;
        // Add on the tun header
        p -= 4;
-       *(u32 *)p = htonl(0x00000800);
+       *(uint32_t *) p = htonl(PKTIP);
        l += 4;
 
        l += 4;
 
-       if (session[s].tbf_in && !config->cluster_iam_master) { // Are we throttled and a slave?
-               master_throttle_packet(session[s].tbf_in, p, l); // Pass it to the master for handling.
+       // Are we throttled and a slave?
+       if (session[s].tbf_in && !config->cluster_iam_master) {
+               // Pass it to the master for handling.
+               master_throttle_packet(session[s].tbf_in, p, l);
                return;
        }
 
                return;
        }
 
-       session[s].cin += l - 4;
-       session[s].total_cin += l - 4;
-       sess_count[s].cin += l - 4;
+       // Are we throttled and a master??
+       if (session[s].tbf_in && config->cluster_iam_master) {
+               // Actually handle the throttled packets.
+               tbf_queue_packet(session[s].tbf_in, p, l);
+               return;
+       }
 
 
-       session[s].pin++;
-       eth_tx += l - 4;
+       // send to ethernet
+       if (tun_write(p, l) < 0)
+       {
+               STAT(tun_tx_errors);
+               LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
+                       l, strerror(errno), tunfd, p);
+
+               return;
+       }
+
+       p += 4;
+       l -= 4;
 
        if (session[s].snoop_ip && session[s].snoop_port)
        {
 
        if (session[s].snoop_ip && session[s].snoop_port)
        {
-               // Snooping this session, send it to ASIO
+               // Snooping this session
                snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
        }
                snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
        }
+
+       increment_counter(&session[s].cin, &session[s].cin_wrap, l);
+       session[s].cin_delta += l;
+       session[s].pin++;
+
+       sess_local[s].cin += l;
+       sess_local[s].pin++;
+
+       eth_tx += l;
+
        STAT(tun_tx_packets);
        INC_STAT(tun_tx_bytes, l);
        STAT(tun_tx_packets);
        INC_STAT(tun_tx_bytes, l);
+}
 
 
-       if (session[s].tbf_in && config->cluster_iam_master) { // Are we throttled and a master?? actually handle the throttled packets.
+// process IPv6 packet received
+//
+// This MUST be called with at least 4 byte behind 'p'.
+// (i.e. this routine writes to p[-4]).
+void processipv6in(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
+{
+       struct in6_addr ip;
+       in_addr_t ipv4;
+
+       CSTAT(processipv6in);
+
+       LOG_HEX(5, "IPv6", p, l);
+
+       ip = *(struct in6_addr *) (p + 8);
+       ipv4 = ntohl(*(uint32_t *)(p + 16));
+
+       if (l > MAXETHER)
+       {
+               LOG(1, s, t, "IP packet too long %d\n", l);
+               STAT(tunnel_rx_errors);
+               return ;
+       }
+
+       if (session[s].ppp.phase != Network || session[s].ppp.ipv6cp != Opened)
+               return;
+
+       // no spoof
+       if (ipv4 != session[s].ip && memcmp(&config->ipv6_prefix, &ip, 8) && sessionbyipv6(ip) != s)
+       {
+               char str[INET6_ADDRSTRLEN];
+               LOG(5, s, t, "Dropping packet with spoofed IP %s\n",
+                               inet_ntop(AF_INET6, &ip, str, INET6_ADDRSTRLEN));
+               return;
+       }
+
+       // Check if it's a Router Solicition message.
+       if (*(p + 6) == 58 && *(p + 7) == 255 && *(p + 24) == 0xFF && *(p + 25) == 2 &&
+                       *(uint32_t *)(p + 26) == 0 && *(uint32_t *)(p + 30) == 0 &&
+                       *(uint32_t *)(p + 34) == 0 &&
+                       *(p + 38) == 0 && *(p + 39) == 2 && *(p + 40) == 133) {
+               LOG(3, s, t, "Got IPv6 RS\n");
+               send_ipv6_ra(s, t, &ip);
+               return;
+       }
+
+       // Add on the tun header
+       p -= 4;
+       *(uint32_t *) p = htonl(PKTIPV6);
+       l += 4;
+
+       // Are we throttled and a slave?
+       if (session[s].tbf_in && !config->cluster_iam_master) {
+               // Pass it to the master for handling.
+               master_throttle_packet(session[s].tbf_in, p, l);
+               return;
+       }
+
+       // Are we throttled and a master??
+       if (session[s].tbf_in && config->cluster_iam_master) {
+               // Actually handle the throttled packets.
                tbf_queue_packet(session[s].tbf_in, p, l);
                return;
        }
                tbf_queue_packet(session[s].tbf_in, p, l);
                return;
        }
@@ -643,194 +1503,382 @@ void processipin(tunnelidt t, sessionidt s, u8 * p, u16 l)
        if (tun_write(p, l) < 0)
        {
                STAT(tun_tx_errors);
        if (tun_write(p, l) < 0)
        {
                STAT(tun_tx_errors);
-               log(0, 0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
+               LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
                        l, strerror(errno), tunfd, p);
                        l, strerror(errno), tunfd, p);
+
+               return;
+       }
+
+       p += 4;
+       l -= 4;
+
+       if (session[s].snoop_ip && session[s].snoop_port)
+       {
+               // Snooping this session
+               snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
        }
 
        }
 
+       increment_counter(&session[s].cin, &session[s].cin_wrap, l);
+       session[s].cin_delta += l;
+       session[s].pin++;
+
+       sess_local[s].cin += l;
+       sess_local[s].pin++;
+
+       eth_tx += l;
+
+       STAT(tun_tx_packets);
+       INC_STAT(tun_tx_bytes, l);
 }
 
 //
 // Helper routine for the TBF filters.
 // Used to send queued data in from the user.
 //
 }
 
 //
 // Helper routine for the TBF filters.
 // Used to send queued data in from the user.
 //
-void send_ipin(sessionidt s, u8 *buf, int len)
+void send_ipin(sessionidt s, uint8_t *buf, int len)
 {
 {
-       log_hex(5, "IP in throttled", buf, len);
+       LOG_HEX(5, "IP in throttled", buf, len);
+
        if (write(tunfd, buf, len) < 0)
        {
                STAT(tun_tx_errors);
        if (write(tunfd, buf, len) < 0)
        {
                STAT(tun_tx_errors);
-               log(0, 0, 0, 0, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
+               LOG(0, 0, 0, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
                        len, strerror(errno), tunfd, buf);
                        len, strerror(errno), tunfd, buf);
+
+               return;
        }
 
        }
 
-       // Increment packet counters
-       session[s].cin += len - 4;
-       session[s].total_cin += len - 4;
-       sess_count[s].cin += len - 4;
+       buf += 4;
+       len -= 4;
+
+       if (session[s].snoop_ip && session[s].snoop_port)
+       {
+               // Snooping this session
+               snoop_send_packet(buf, len, session[s].snoop_ip, session[s].snoop_port);
+       }
 
 
+       // Increment packet counters
+       increment_counter(&session[s].cin, &session[s].cin_wrap, len);
+       session[s].cin_delta += len;
        session[s].pin++;
        session[s].pin++;
-       eth_tx += len - 4;
+
+       sess_local[s].cin += len;
+       sess_local[s].pin++;
+
+       eth_tx += len;
+
+       STAT(tun_tx_packets);
+       INC_STAT(tun_tx_bytes, len - 4);
 }
 
 
 }
 
 
-// Process LCP messages
-void processccp(tunnelidt t, sessionidt s, u8 * p, u16 l)
+// Process CCP messages
+void processccp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 {
 {
+       uint8_t b[MAXETHER];
+       uint8_t *q;
 
 
-       CSTAT(call_processccp);
+       CSTAT(processccp);
 
 
-       log_hex(5, "CCP", p, l);
-       if (l < 2 || (*p != ConfigReq && *p != TerminateReq))
+       LOG_HEX(5, "CCP", p, l);
+
+       if (session[s].ppp.phase < Network)
        {
        {
-               log(1, 0, s, t, "Unexpecetd CCP request code %d\n", *p);
+               LOG(2, s, t, "CCP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
+               return;
+       }
+
+       if (l < 1)
+       {
+               LOG(1, s, t, "Short CCP packet\n");
                STAT(tunnel_rx_errors);
                STAT(tunnel_rx_errors);
-               return ;
        }
        }
-       // reject
+
+       LOG(3, s, t, "CCP: recv %s\n", ppp_code(*p));
+       if (*p == ConfigAck)
        {
        {
-               u8 b[MAXCONTROL];
-               u8 *q;
-               if (*p == ConfigReq)
+               switch (session[s].ppp.ccp)
                {
                {
-                       if (l < 6)
-                       {
-                               *p = ConfigAck;         // accept no compression
-                       }
-                       else
-                       {
-                               *p = ConfigRej;        // reject
-                       }
+               case RequestSent:
+                       initialise_restart_count(s, ccp);
+                       change_state(s, ccp, AckReceived);
+                       break;
+
+               case AckReceived:
+               case Opened:
+                       LOG(2, s, t, "CCP: ConfigAck in state %s?  Sending ConfigReq\n", ppp_state(session[s].ppp.ccp));
+                       sendccp(s, t);
+                       change_state(s, ccp, RequestSent);
+                       break;
+
+               case AckSent:
+                       LOG(3, s, t, "CCP: Opened\n");
+                       change_state(s, ccp, Opened);
+                       break;
+
+               default:
+                       LOG(2, s, t, "CCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ccp));
                }
                }
-               else
-                       *p = TerminateAck;     // close
-               q = makeppp(b, sizeof(b), p, l, t, s, PPPCCP);
-               if (!q) {
-                       log(1,0,0,0, "Failed to send CCP packet.\n");   
+       }
+       else if (*p == ConfigReq)
+       {
+               if (l < 6) // accept no compression
+                       *p = ConfigAck;
+               else // compression requested--reject
+                       *p = ConfigRej;
+
+               q = makeppp(b, sizeof(b), p, l, s, t, PPPCCP);
+               if (!q) return;
+
+               switch (session[s].ppp.ccp)
+               {
+               case Closed:
+                       q = makeppp(b, sizeof(b), p, 2, s, t, PPPCCP);
+                       if (!q) return;
+                       *q = TerminateAck;
+                       *((uint16_t *) (q + 2)) = htons(l = 4);
+                       break;
+
+               case Stopped:
+                       initialise_restart_count(s, ccp);
+                       sendccp(s, t);
+                       if (*q == ConfigAck)
+                               change_state(s, ccp, AckSent);
+                       else
+                               change_state(s, ccp, RequestSent);
+
+                       break;
+
+               case RequestSent:
+                       if (*q == ConfigAck)
+                               change_state(s, ccp, AckSent);
+
+                       break;
+
+               case AckReceived:
+                       if (*q == ConfigAck)
+                               change_state(s, ccp, Opened);
+
+                       break;
+
+               case Opened:
+                       initialise_restart_count(s, ccp);
+                       sendccp(s, t);
+                       /* fallthrough */
+
+               case AckSent:
+                       if (*q == ConfigAck)
+                               change_state(s, ccp, AckSent);
+                       else
+                               change_state(s, ccp, RequestSent);
+
+                       break;
+
+               default:
+                       LOG(2, s, t, "CCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ccp));
                        return;
                }
                        return;
                }
-               tunnelsend(b, l + (q - b), t); // send it
+
+               LOG(3, s, t, "CCP: send %s\n", ppp_code(*q));
+               tunnelsend(b, l + (q - b), t);
+       }
+       else if (*p == TerminateReq)
+       {
+               *p = TerminateAck;
+               q = makeppp(b, sizeof(b),  p, l, s, t, PPPCCP);
+               if (!q) return;
+               LOG(3, s, t, "CCP: send %s\n", ppp_code(*q));
+               tunnelsend(b, l + (q - b), t);
+               change_state(s, ccp, Stopped);
+       }
+       else if (*p != CodeRej)
+       {
+               int code = *p;
+               int mru = session[s].mru;
+               if (!mru)
+                       mru = DEFAULT_MRU;
+
+               if (l > mru) l = mru;
+
+               *p = CodeRej;
+               q = makeppp(b, sizeof(b), p, l, s, t, PPPCCP);
+               if (!q) return;
+
+               LOG(2, s, t, "Unexpected CCP code %s\n", ppp_code(code));
+               LOG(3, s, t, "CCP: send %s\n", ppp_code(*q));
+               tunnelsend(b, l + (q - b), t);
        }
 }
 
        }
 }
 
-// send a CHAP PP packet
-void sendchap(tunnelidt t, sessionidt s)
+// send a CHAP challenge
+void sendchap(sessionidt s, tunnelidt t)
 {
 {
-       u8 b[MAXCONTROL];
-       u16 r = session[s].radius;
-       u8 *q;
+       uint8_t b[MAXETHER];
+       uint16_t r;
+       uint8_t *q;
 
 
-       CSTAT(call_sendchap);
+       CSTAT(sendchap);
 
 
+       r = radiusnew(s);
        if (!r)
        {
        if (!r)
        {
-               log(1, 0, s, t, "No RADIUS to send challenge\n");
+               LOG(1, s, t, "No RADIUS to send challenge\n");
                STAT(tunnel_tx_errors);
                STAT(tunnel_tx_errors);
-               return ;
-       }
-       log(1, 0, s, t, "Send CHAP challenge\n");
-       {                            // new challenge
-               int n;
-               for (n = 0; n < 15; n++)
-                       radius[r].auth[n] = rand();
+               return;
        }
        }
-       radius[r].chap = 1;          // CHAP not PAP
+
+       LOG(1, s, t, "Send CHAP challenge\n");
+
+       radius[r].chap = 1;             // CHAP not PAP
        radius[r].id++;
        if (radius[r].state != RADIUSCHAP)
                radius[r].try = 0;
        radius[r].id++;
        if (radius[r].state != RADIUSCHAP)
                radius[r].try = 0;
+
        radius[r].state = RADIUSCHAP;
        radius[r].retry = backoff(radius[r].try++);
        if (radius[r].try > 5)
        {
        radius[r].state = RADIUSCHAP;
        radius[r].retry = backoff(radius[r].try++);
        if (radius[r].try > 5)
        {
-               sessionshutdown(s, "Timeout CHAP");
+               sessionshutdown(s, "CHAP timeout.", 3, 0);
                STAT(tunnel_tx_errors);
                return ;
        }
                STAT(tunnel_tx_errors);
                return ;
        }
-       q = makeppp(b, sizeof(b), 0, 0, t, s, PPPCHAP);
-       if (!q) {
-               log(1, 0, s, t, "failed to send CHAP challenge.\n");
-               return;
-       }
-       *q = 1;                      // challenhe
-       q[1] = radius[r].id;         // ID
-       q[4] = 16;                   // length
-       memcpy(q + 5, radius[r].auth, 16); // challenge
-       strcpy(q + 21, hostname);    // our name
-       *(u16 *) (q + 2) = htons(strlen(hostname) + 21); // length
+       q = makeppp(b, sizeof(b), 0, 0, s, t, PPPCHAP);
+       if (!q) return;
+
+       *q = 1;                                 // challenge
+       q[1] = radius[r].id;                    // ID
+       q[4] = 16;                              // value size (size of challenge)
+       memcpy(q + 5, radius[r].auth, 16);      // challenge
+       strcpy((char *) q + 21, hostname);      // our name
+       *(uint16_t *) (q + 2) = htons(strlen(hostname) + 21); // length
        tunnelsend(b, strlen(hostname) + 21 + (q - b), t); // send it
 }
 
 // fill in a L2TP message with a PPP frame,
 // copies existing PPP message and changes magic number if seen
 // returns start of PPP frame
        tunnelsend(b, strlen(hostname) + 21 + (q - b), t); // send it
 }
 
 // fill in a L2TP message with a PPP frame,
 // copies existing PPP message and changes magic number if seen
 // returns start of PPP frame
-u8 *makeppp(u8 * b, int size, u8 * p, int l, tunnelidt t, sessionidt s, u16 mtype)
+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_backtrace(backtrace_count, 5)
+               return NULL;
+       }
 
 
-       if (size < 12)
-               return NULL;    // Need more space than this!!
-
-       *(u16 *) (b + 0) = htons(0x0002); // L2TP with no options
-       *(u16 *) (b + 2) = htons(tunnel[t].far); // tunnel
-       *(u16 *) (b + 4) = htons(session[s].far); // session
+       *(uint16_t *) (b + 0) = htons(0x0002); // L2TP with no options
+       *(uint16_t *) (b + 2) = htons(tunnel[t].far); // tunnel
+       *(uint16_t *) (b + 4) = htons(session[s].far); // session
        b += 6;
        b += 6;
-       if (mtype != PPPLCP && !(session[s].l2tp_flags & SESSIONACFC))
+       if (mtype == PPPLCP || !(session[s].l2tp_flags & SESSIONACFC))
        {
        {
-               *(u16 *) b = htons(0xFF03); // HDLC header
+               *(uint16_t *) b = htons(0xFF03); // HDLC header
                b += 2;
        }
        if (mtype < 0x100 && session[s].l2tp_flags & SESSIONPFC)
                *b++ = mtype;
        else
        {
                b += 2;
        }
        if (mtype < 0x100 && session[s].l2tp_flags & SESSIONPFC)
                *b++ = mtype;
        else
        {
-               *(u16 *) b = htons(mtype);
+               *(uint16_t *) b = htons(mtype);
                b += 2;
        }
 
                b += 2;
        }
 
-       if (l + 12 > size) {
-               log(3,0,0,0, "Would have overflowed the buffer in makeppp: size %d, len %d.\n", size, l);
-               return NULL;    // Run out of room to hold the packet!
+       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_backtrace(backtrace_count, 5)
+               return NULL;
        }
        }
+
        if (p && l)
                memcpy(b, p, l);
        if (p && l)
                memcpy(b, p, l);
+
        return b;
 }
 
        return b;
 }
 
-// find a PPP option, returns point to option, or 0 if not found
-u8 *findppp(u8 * b, u8 mtype)
+static int add_lcp_auth(uint8_t *b, int size, int authtype)
 {
 {
-       u16 l = ntohs(*(u16 *) (b + 2));
-       if (l < 4)
+       int len = 0;
+       if ((authtype == AUTHCHAP && size < 5) || size < 4)
                return 0;
                return 0;
-       b += 4;
-       l -= 4;
-       while (l)
+
+       *b++ = 3; // Authentication-Protocol
+       if (authtype == AUTHCHAP)
+       {
+               len = *b++ = 5; // length
+               *(uint16_t *) b = htons(PPPCHAP); b += 2;
+               *b++ = 5; // MD5
+       }
+       else if (authtype == AUTHPAP)
+       {
+               len = *b++ = 4; // length
+               *(uint16_t *) b = htons(PPPPAP); b += 2;
+       }
+       else
        {
        {
-               if (l < b[1] || !b[1])
-                       return 0;            // faulty
-               if (*b == mtype)
-                       return b;
-               l -= b[1];
-               b += b[1];
+               LOG(0, 0, 0, "add_lcp_auth called with unsupported auth type %d\n", authtype);
        }
        }
-       return 0;
+
+       return len;
 }
 
 }
 
-// Send initial LCP ConfigReq
-void initlcp(tunnelidt t, sessionidt s)
+// Send initial LCP ConfigReq for MRU, authentication type and magic no
+void sendlcp(sessionidt s, tunnelidt t)
 {
 {
-       char b[500] = {0}, *q;
+       uint8_t b[500], *q, *l;
+       int authtype = sess_local[s].lcp_authtype;
 
 
-       q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP);
-       if (!q) {
-               log(1, 0, s, t, "Failed to send LCP ConfigReq.\n");
+       if (!(q = makeppp(b, sizeof(b), NULL, 0, s, t, PPPLCP)))
                return;
                return;
+
+       LOG(3, s, t, "LCP: send ConfigReq%s%s%s\n",
+           authtype ? " (" : "",
+           authtype ? (authtype == AUTHCHAP ? "CHAP" : "PAP") : "",
+           authtype ? ")" : "");
+
+       l = q;
+       *l++ = ConfigReq;
+       *l++ = (time_now % 255) + 1; // ID
+
+       l += 2; //Save space for length
+
+       if (session[s].mru)
+       {
+               *l++ = 1; *l++ = 4; // Maximum-Receive-Unit (length 4)
+               *(uint16_t *) l = htons(session[s].mru); l += 2;
        }
        }
-       log(4, 0, s, t, "Sending LCP ConfigReq for PAP\n");
-       *q = ConfigReq;
-       *(u8 *)(q + 1) = (time_now % 255) + 1; // ID
-       *(u16 *)(q + 2) = htons(8); // Length
-       *(u8 *)(q + 4) = 3;
-       *(u8 *)(q + 5) = 4;
-       *(u16 *)(q + 6) = htons(0xC023); // PAP
-       tunnelsend(b, 12 + 8, t);
+
+       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;
+
+       *(uint16_t *)(q + 2) = htons(l - q); // Length
+
+       LOG_HEX(5, "PPPLCP", q, l - q);
+       if (config->debug > 3) dumplcp(q, l - q);
+
+       tunnelsend(b, (l - b), t);
 }
 
 }
 
+// Send CCP request for no compression
+void sendccp(sessionidt s, tunnelidt t)
+{
+       uint8_t b[500], *q;
+
+       if (!(q = makeppp(b, sizeof(b), NULL, 0, s, t, PPPCCP)))
+               return;
+
+       LOG(3, s, t, "CCP: send ConfigReq (no compression)\n");
+
+       *q = ConfigReq;
+       *(uint8_t *)(q + 1) = (time_now % 255) + 1; // ID
+       *(uint16_t *)(q + 2) = htons(4); // Length
+
+       LOG_HEX(5, "PPPCCP", q, 4);
+       tunnelsend(b, (q - b) + 4 , t);
+}
for cloning use: "git clone git://git.sameswireless.fr/l2tpns.git" ; For add to your sources.list: "deb http://package.sameswifi.fr/ jessie main"