update filter refcounts

[l2tpns.git] / ppp.c

diff --git a/ppp.c b/ppp.c
index a0f7cc2..d44ed25 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 1.21 2004-11-05 04:55:27 bodea Exp $";
+char const *cvs_id_ppp = "$Id: ppp.c,v 1.31 2004-11-27 05:19:53 bodea Exp $";

 
 #include <stdio.h>
 #include <string.h>
 
 #include <stdio.h>
 #include <string.h>


@@ -21,9 +21,9 @@ extern int tunfd;
 extern char hostname[];
 extern u32 eth_tx;
 extern time_t time_now;
 extern char hostname[];
 extern u32 eth_tx;
 extern time_t time_now;

-extern struct configt *config;
+extern configt *config;

 
 

-void sendccp(tunnelidt t, sessionidt s);
+static void initccp(tunnelidt t, sessionidt s);

 
 // Process PAP messages
 void processpap(tunnelidt t, sessionidt s, u8 *p, u16 l)
 
 // Process PAP messages
 void processpap(tunnelidt t, sessionidt s, u8 *p, u16 l)


@@ -75,10 +75,8 @@ void processpap(tunnelidt t, sessionidt s, u8 *p, u16 l)
                u8 b[MAXCONTROL];
                u8 id = p[1];
                u8 *p = makeppp(b, sizeof(b), 0, 0, t, s, PPPPAP);
                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;
-               }
+               if (!p) return;
+

                if (session[s].ip)
                        *p = 2;                 // ACK
                else
                if (session[s].ip)
                        *p = 2;                 // ACK
                else


@@ -224,7 +222,7 @@ void processchap(tunnelidt t, sessionidt s, u8 *p, u16 l)
        radiussend(r, RADIUSAUTH);
 }
 
        radiussend(r, RADIUSAUTH);
 }
 

-char *ppp_lcp_types[] = {
+static char *ppp_lcp_types[] = {

        NULL,
        "ConfigReq",
        "ConfigAck",
        NULL,
        "ConfigReq",
        "ConfigAck",


@@ -240,7 +238,7 @@ char *ppp_lcp_types[] = {
        "IdentRequest",
 };
 
        "IdentRequest",
 };
 

-void dumplcp(u8 *p, int l)
+static void dumplcp(u8 *p, int l)

 {
        int x = l - 4;
        u8 *o = (p + 4);
 {
        int x = l - 4;
        u8 *o = (p + 4);


@@ -275,46 +273,45 @@ void dumplcp(u8 *p, int l)
                                else
                                        LOG(4, 0, 0, 0, "    %s odd length %d\n", lcp_types[type], length);
                                break;
                                else
                                        LOG(4, 0, 0, 0, "    %s odd length %d\n", lcp_types[type], length);
                                break;

+                       case 2: // Async-Control-Character-Map
+                               if (length == 6)
+                               {
+                                       u32 asyncmap = ntohl(*(u32 *)(o + 2));
+                                       LOG(4, 0, 0, 0, "    %s %x\n", lcp_types[type], asyncmap);
+                               }
+                               else
+                                       LOG(4, 0, 0, 0, "   %s odd length %d\n", lcp_types[type], length);
+                               break;

                        case 3: // Authentication-Protocol
                        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 == PPPCHAP ? "CHAP" :
-                                                       proto == PPPPAP  ? "PAP"  : "UNKNOWN");
-                                       }
-                                       else
-                                               LOG(4, 0, 0, 0, "   %s odd length %d\n", lcp_types[type], length);
-                                       break;
+                                       int proto = ntohs(*(u16 *)(o + 2));
+                                       LOG(4, 0, 0, 0, "   %s 0x%x (%s)\n", lcp_types[type], proto,
+                                               proto == PPPCHAP ? "CHAP" :
+                                               proto == PPPPAP  ? "PAP"  : "UNKNOWN");

                                }
                                }

+                               else
+                                       LOG(4, 0, 0, 0, "   %s odd length %d\n", lcp_types[type], length);
+                               break;

                        case 4: // Quality-Protocol
                                {
                                        u32 qp = ntohl(*(u32 *)(o + 2));
                                        LOG(4, 0, 0, 0, "    %s %x\n", lcp_types[type], qp);
                        case 4: // Quality-Protocol
                                {
                                        u32 qp = ntohl(*(u32 *)(o + 2));
                                        LOG(4, 0, 0, 0, "    %s %x\n", lcp_types[type], qp);

-                                       break;

                                }
                                }

+                               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;
+                                       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;

                        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, 0, "    %s\n", lcp_types[type]);
+                               break;

                        default:
                                LOG(2, 0, 0, 0, "    Unknown PPP LCP Option type %d\n", type);
                                break;
                        default:
                                LOG(2, 0, 0, 0, "    Unknown PPP LCP Option type %d\n", type);
                                break;


@@ -359,6 +356,7 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
        {
                int x = l - 4;
                u8 *o = (p + 4);
        {
                int x = l - 4;
                u8 *o = (p + 4);

+               u8 response = 0;

 
                LOG(3, session[s].ip, s, t, "LCP: ConfigReq (%d bytes)...\n", l);
                if (config->debug > 3) dumplcp(p, l);
 
                LOG(3, session[s].ip, s, t, "LCP: ConfigReq (%d bytes)...\n", l);
                if (config->debug > 3) dumplcp(p, l);


@@ -367,115 +365,135 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
                {
                        int type = o[0];
                        int length = o[1];
                {
                        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
                                        session[s].mru = ntohs(*(u16 *)(o + 2));
                                        break;
                        switch (type)
                        {
                                case 1: // Maximum-Receive-Unit
                                        session[s].mru = ntohs(*(u16 *)(o + 2));
                                        break;

-                               case 2: // asyncmap
-                                       LOG_HEX(2, "PPP LCP Packet", p, l);
-                                       LOG(2, 0, 0, 0, "PPP LCP Packet type %d (%s len %d)\n", *p, ppp_lcp_types[(int)*p], ntohs( ((u16 *) p)[1]) );
+
+                               case 2: // Async-Control-Character-Map
+                                       if (!ntohl(*(u32 *)(o + 2))) // all bits zero is OK
+                                               break;
+
+                                       if (response && response != ConfigNak) // rej already queued
+                                               break;
+
+                                       LOG(2, session[s].ip, s, t, "    Remote requesting asyncmap.  Rejecting.\n");
+                                       if (!response)
+                                       {
+                                               q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP);
+                                               if (!q) break;
+                                               response = *q++ = ConfigNak;
+                                       }
+
+                                       if ((q - b + 11) > sizeof(b))
+                                       {
+                                               LOG(2, session[s].ip, s, t, "LCP overflow for asyncmap ConfigNak.\n");
+                                               break;
+                                       }
+
+                                       *q++ = type;
+                                       *q++ = 6;
+                                       memset(q, 0, 4); // asyncmap 0
+                                       q += 4;

                                        break;
                                        break;

+

                                case 3: // Authentication-Protocol
                                        {
                                                int proto = ntohs(*(u16 *)(o + 2));
                                case 3: // Authentication-Protocol
                                        {
                                                int proto = ntohs(*(u16 *)(o + 2));

+                                               char proto_name[] = "0x0000";
+                                               if (proto == PPPPAP)
+                                                       break;
+
+                                               if (response && response != ConfigNak) // rej already queued
+                                                       break;
+

                                                if (proto == PPPCHAP)
                                                if (proto == PPPCHAP)

+                                                       strcpy(proto_name, "CHAP");
+                                               else
+                                                       sprintf(proto_name, "%#4.4x", proto);
+
+                                               LOG(2, session[s].ip, s, t, "    Remote requesting %s authentication.  Rejecting.\n", proto_name);
+
+                                               if (!response)

                                                {
                                                {

-                                                       LOG(2, session[s].ip, s, t, "    Remote end is trying to do CHAP. Rejecting it.\n");
-
-                                                       if (!q)
-                                                       {
-                                                               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;
-                                                       }
-                                                       memcpy(q, o, length);
-                                                       *(u16 *)(q += 2) = htons(PPPPAP); // NAK -> Use PAP instead
-                                                       q += length;
+                                                       q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP);
+                                                       if (!q) break;
+                                                       response = *q++ = ConfigNak;

                                                }
                                                }

-                                               break;
+
+                                               if ((q - b + length) > sizeof(b))
+                                               {
+                                                       LOG(2, session[s].ip, s, t, "LCP overflow for %s ConfigNak.\n", proto_name);
+                                                       break;
+                                               }
+
+                                               memcpy(q, o, length);
+                                               *(u16 *)(q += 2) = htons(PPPPAP); // NAK -> Use PAP instead
+                                               q += length;

                                        }
                                        }

+                                       break;
+

                                case 5: // Magic-Number
                                case 5: // Magic-Number

-                                       {
-                                               magicno = ntohl(*(u32 *)(o + 2));
-                                               break;
-                                       }
+                                       magicno = ntohl(*(u32 *)(o + 2));
+                                       break;
+

                                case 4: // Quality-Protocol
                                case 7: // Protocol-Field-Compression
                                case 8: // Address-And-Control-Field-Compression
                                case 4: // Quality-Protocol
                                case 7: // Protocol-Field-Compression
                                case 8: // Address-And-Control-Field-Compression

+                                       break;
+
+                               default: // Reject any unknown options
+                                       LOG(2, session[s].ip, s, t, "    Rejecting PPP LCP Option type %d\n", type);
+                                       if (!response || response != ConfigRej) // drop nak in favour of rej
+                                       {
+                                               q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP);
+                                               if (!q) return;
+                                               response = *q++ = ConfigRej;
+                                       }
+
+                                       if ((q - b + length) > sizeof(b))
+                                       {
+                                               LOG(2, session[s].ip, s, t, "LCP overflow for ConfigRej (type=%d).\n", type);

                                                break;
                                                break;

-                               case 13: // CallBack option for LCP extention of win2000/routers L2TP client
-                               case 17:
-                               case 18:
-                               {
-                                       // Reject LCP CallBack
-                                       LOG(2, session[s].ip, s, t, "    PPP LCP Option type %d, len=%d\n", type, length);
-                                       memcpy(p + 4, o, length);
-                                       *(u16 *)(p + 2) = htons(length + 4);
-                                       *p = ConfigRej;
-                                       q = makeppp(b,sizeof(b), p, length + 4, t, s, PPPLCP);
-                                       tunnelsend(b, 12 + length + 4, t);
-                                       return;

                                        }
 
                                        }
 

-                               default:
-                                       // Reject Unknown LCP Option to stop to send it again
-                                       LOG(2, session[s].ip, s, t, "    Unknown PPP LCP Option type %d\n", type);
-                                       memcpy(p + 4, o, length);
-                                       *(u16 *)(p + 2) = htons(length + 4);
-                                       *p = ConfigRej;
-                                       q = makeppp(b,sizeof(b), p, length + 4, t, s, PPPLCP);
-                                       tunnelsend(b, 12 + length + 4, t);
-                                       return;
+                                       memcpy(q, o, length);
+                                       q += length;

                        }
                        x -= length;
                        o += length;
                }
 
                        }
                        x -= length;
                        o += length;
                }
 

-               if (!(session[s].flags & SF_LCP_ACKED))
-                       initlcp(t, s);
-
-               if (!q)
+               if (!response)

                {
                        // Send back a ConfigAck
                {
                        // 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);
                        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);
-               }
-               else
-               {
-                       // Already built a ConfigNak... send it
-                       LOG(3, session[s].ip, s, t, "Sending ConfigNak\n");
-                       tunnelsend(b, l + (q - b), t);
+                       if (!q) return;
+                       response = *q = ConfigAck;

                }
                }

+
+               LOG(3, session[s].ip, s, t, "Sending %s\n", ppp_lcp_types[response]);
+               tunnelsend(b, l + (q - b), t);
+
+               if (!(session[s].flags & SF_LCP_ACKED))
+                       initlcp(t, s);

        }
        else if (*p == ConfigNak)
        {
        }
        else if (*p == ConfigNak)
        {

-               LOG(1, session[s].ip, s, t, "Remote end sent a ConfigNak. Ignoring\n");
+               LOG(1, session[s].ip, s, t, "Remote end sent a ConfigNak.  Ignoring\n");

                if (config->debug > 3) dumplcp(p, l);
                return ;
        }
        else if (*p == TerminateReq)
        {
                if (config->debug > 3) dumplcp(p, l);
                return ;
        }
        else if (*p == TerminateReq)
        {

+               LOG(3, session[s].ip, s, t, "LCP: Received TerminateReq.  Sending TerminateAck\n");

                *p = TerminateAck;      // close
                q = makeppp(b, sizeof(b),  p, l, t, s, PPPLCP);
                *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.");
+               if (!q) return;

                tunnelsend(b, l + (q - b), t); // send it
                tunnelsend(b, l + (q - b), t); // send it

+               sessionshutdown(s, "Remote end closed connection.");

        }
        else if (*p == TerminateAck)
        {
        }
        else if (*p == TerminateAck)
        {


@@ -483,14 +501,11 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
        }
        else if (*p == EchoReq)
        {
        }
        else if (*p == EchoReq)
        {

+               LOG(5, session[s].ip, s, t, "LCP: Received EchoReq.  Sending EchoReply\n");

                *p = EchoReply;         // reply
                *(u32 *) (p + 4) = htonl(session[s].magic); // our magic number
                q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
                *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");
-                       return;
-               }
-               LOG(5, session[s].ip, s, t, "LCP: Received EchoReq. Sending EchoReply\n");
+               if (!q) return;

                tunnelsend(b, l + (q - b), t); // send it
        }
        else if (*p == EchoReply)
                tunnelsend(b, l + (q - b), t); // send it
        }
        else if (*p == EchoReply)


@@ -506,11 +521,7 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
                        l = 1400;
                }
                q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
                        l = 1400;
                }
                q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);

-               if (!q)
-               {
-                       LOG(3, session[s].ip, s, t, "Failed to create IdentRej.\n");
-                       return;
-               }
+               if (!q) return;

                LOG_HEX(5, "LCPIdentRej", q, l + 4);
                tunnelsend(b, 12 + 4 + l, t);
        }
                LOG_HEX(5, "LCPIdentRej", q, l + 4);
                tunnelsend(b, 12 + 4 + l, t);
        }


@@ -522,6 +533,26 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
        }
 }
 
        }
 }
 

+// find a PPP option, returns point to option, or 0 if not found
+static u8 *findppp(u8 *b, u8 mtype)
+{
+       u16 l = ntohs(*(u16 *) (b + 2));
+       if (l < 4)
+               return 0;
+       b += 4;
+       l -= 4;
+       while (l)
+       {
+               if (l < b[1] || !b[1])
+                       return 0;               // faulty
+               if (*b == mtype)
+                       return b;
+               l -= b[1];
+               b += b[1];
+       }
+       return 0;
+}
+

 // Process IPCP messages
 void processipcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
 {
 // Process IPCP messages
 void processipcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
 {


@@ -559,6 +590,10 @@ void processipcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
                session[s].flags |= SF_IPCP_ACKED;
 
                LOG(3, session[s].ip, s, t, "IPCP Acked, session is now active\n");
                session[s].flags |= SF_IPCP_ACKED;
 
                LOG(3, session[s].ip, s, t, "IPCP Acked, session is now active\n");

+
+               // clear LCP_ACKED/CCP_ACKED flag for possible fast renegotiaion for routers
+               session[s].flags &= ~(SF_LCP_ACKED|SF_CCP_ACKED);
+

                return;
        }
        if (*p != ConfigReq)
                return;
        }
        if (*p != ConfigReq)


@@ -594,10 +629,8 @@ void processipcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
                        u16 n = 4;
                        i = p + l;
                        if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP)))
                        u16 n = 4;
                        i = p + l;
                        if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP)))

-                       {
-                               LOG(2, 0, s, t, "Failed to send IPCP ConfigRej\n");

                                return;
                                return;

-                       }
+

                        *q = ConfigRej;
                        p += 4;
                        while (p < i && p[1])
                        *q = ConfigRej;
                        p += 4;
                        while (p < i && p[1])


@@ -651,10 +684,8 @@ void processipcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
                                                inet_toa(htonl(session[s].ip)));
                        }
                        if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP)))
                                                inet_toa(htonl(session[s].ip)));
                        }
                        if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP)))

-                       {
-                               LOG(2, 0, s, t, " Failed to send IPCP packet.\n");

                                return;
                                return;

-                       }
+

                        tunnelsend(b, l + (q - b), t); // send it
                }
        }
                        tunnelsend(b, l + (q - b), t); // send it
                }
        }


@@ -688,12 +719,6 @@ void processipin(tunnelidt t, sessionidt s, u8 *p, u16 l)
                return;
        }
 
                return;
        }
 

-       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);
-       }
-

        // Add on the tun header
        p -= 4;
        *(u32 *)p = htonl(0x00000800);
        // Add on the tun header
        p -= 4;
        *(u32 *)p = htonl(0x00000800);


@@ -704,16 +729,6 @@ void processipin(tunnelidt t, sessionidt s, u8 *p, u16 l)
                return;
        }
 
                return;
        }
 

-       session[s].cin += l - 4;
-       session[s].total_cin += l - 4;
-       sess_count[s].cin += l - 4;
-
-       session[s].pin++;
-       eth_tx += l - 4;
-
-       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.
                tbf_queue_packet(session[s].tbf_in, p, l);
                return;
        if (session[s].tbf_in && config->cluster_iam_master) { // Are we throttled and a master?? actually handle the throttled packets.
                tbf_queue_packet(session[s].tbf_in, p, l);
                return;


@@ -725,8 +740,25 @@ void processipin(tunnelidt t, sessionidt s, u8 *p, u16 l)
                STAT(tun_tx_errors);
                LOG(0, 0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
                        l, strerror(errno), tunfd, p);
                STAT(tun_tx_errors);
                LOG(0, 0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
                        l, strerror(errno), tunfd, p);

+
+               return;

        }
 
        }
 

+       if (session[s].snoop_ip && session[s].snoop_port)
+       {
+               // Snooping this session
+               snoop_send_packet(p + 4, l - 4, session[s].snoop_ip, session[s].snoop_port);
+       }
+
+       session[s].cin += l - 4;
+       session[s].total_cin += l - 4;
+       sess_count[s].cin += l - 4;
+
+       session[s].pin++;
+       eth_tx += l - 4;
+
+       STAT(tun_tx_packets);
+       INC_STAT(tun_tx_bytes, l - 4);

 }
 
 //
 }
 
 //


@@ -736,11 +768,20 @@ void processipin(tunnelidt t, sessionidt s, u8 *p, u16 l)
 void send_ipin(sessionidt s, u8 *buf, int len)
 {
        LOG_HEX(5, "IP in throttled", buf, len);
 void send_ipin(sessionidt s, u8 *buf, int len)
 {
        LOG_HEX(5, "IP in throttled", buf, len);

+

        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",
                        len, strerror(errno), tunfd, buf);
        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",
                        len, strerror(errno), tunfd, buf);

+
+               return;
+       }
+
+       if (session[s].snoop_ip && session[s].snoop_port)
+       {
+               // Snooping this session
+               snoop_send_packet(buf + 4, len - 4, session[s].snoop_ip, session[s].snoop_port);

        }
 
        // Increment packet counters
        }
 
        // Increment packet counters


@@ -750,47 +791,61 @@ void send_ipin(sessionidt s, u8 *buf, int len)
 
        session[s].pin++;
        eth_tx += len - 4;
 
        session[s].pin++;
        eth_tx += len - 4;

+
+       STAT(tun_tx_packets);
+       INC_STAT(tun_tx_bytes, len - 4);

 }
 
 
 // Process CCP messages
 void processccp(tunnelidt t, sessionidt s, u8 *p, u16 l)
 {
 }
 
 
 // Process CCP messages
 void processccp(tunnelidt t, sessionidt s, u8 *p, u16 l)
 {

+       u8 b[MAXCONTROL];
+       u8 *q;

 
        CSTAT(call_processccp);
 
        LOG_HEX(5, "CCP", p, l);
 
        CSTAT(call_processccp);
 
        LOG_HEX(5, "CCP", p, l);

-       if (l < 2 || (*p != ConfigReq && *p != TerminateReq))
+       switch (l > 1 ? *p : 0)

        {
        {

-               LOG(1, 0, s, t, "Unexpected CCP request code %d\n", *p);
-               STAT(tunnel_rx_errors);
-               return ;
-       }
-       // reject
-       {
-               u8 b[MAXCONTROL];
-               u8 *q;
-               if (*p == ConfigReq)
+       case ConfigAck:
+               session[s].flags |= SF_CCP_ACKED;
+               return;
+
+       case ConfigReq:
+               if (l < 6) // accept no compression

                {
                {

-                       if (l < 6)
-                       {
-                               *p = ConfigAck;         // accept no compression
-                       }
-                       else
-                       {
-                               *p = ConfigRej;         // reject
-                               sendccp(t, s);
-                       }
+                       *p = ConfigAck;
+                       break;

                }
                }

+
+               // compression requested--reject
+               *p = ConfigRej;
+
+               // send CCP request for no compression for our end if not negotiated
+               if (!(session[s].flags & SF_CCP_ACKED))
+                       initccp(t, s);
+
+               break;
+
+       case TerminateReq:
+               *p = TerminateAck;
+               break;
+
+       default:
+               if (l > 1)
+                       LOG(1, 0, s, t, "Unexpected CCP request code %d\n", *p);

                else
                else

-                       *p = TerminateAck;              // close
-               if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPCCP)))
-               {
-                       LOG(1,0,0,0, "Failed to send CCP packet.\n");   
-                       return;
-               }
-               tunnelsend(b, l + (q - b), t); // send it
+                       LOG(1, 0, s, t, "Short CCP packet\n");
+
+               STAT(tunnel_rx_errors);
+               return;

        }
        }

+
+       if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPCCP)))
+               return;
+
+       tunnelsend(b, l + (q - b), t); // send it

 }
 
 // send a CHAP PP packet
 }
 
 // send a CHAP PP packet


@@ -828,10 +883,8 @@ void sendchap(tunnelidt t, sessionidt s)
                return ;
        }
        q = makeppp(b, sizeof(b), 0, 0, t, s, PPPCHAP);
                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;
-       }
+       if (!q) return;
+

        *q = 1;                                 // challenge
        q[1] = radius[r].id;                    // ID
        q[4] = 16;                              // length
        *q = 1;                                 // challenge
        q[1] = radius[r].id;                    // ID
        q[4] = 16;                              // length


@@ -846,8 +899,13 @@ void sendchap(tunnelidt t, sessionidt s)
 // returns start of PPP frame
 u8 *makeppp(u8 *b, int size, u8 *p, int l, tunnelidt t, sessionidt s, u16 mtype)
 {
 // returns start of PPP frame
 u8 *makeppp(u8 *b, int size, u8 *p, int l, tunnelidt t, sessionidt s, u16 mtype)
 {

-       if (size < 12)
-               return NULL;    // Need more space than this!!
+       if (size < 12) // Need more space than this!!
+       {
+               static int backtrace_count = 0;
+               LOG(0, session[s].ip, s, t, "makeppp buffer too small for L2TP header (size=%d)\n", size);
+               log_backtrace(backtrace_count, 5)
+               return NULL;
+       }

 
        *(u16 *) (b + 0) = htons(0x0002); // L2TP with no options
        *(u16 *) (b + 2) = htons(tunnel[t].far); // tunnel
 
        *(u16 *) (b + 0) = htons(0x0002); // L2TP with no options
        *(u16 *) (b + 2) = htons(tunnel[t].far); // tunnel


@@ -866,45 +924,28 @@ u8 *makeppp(u8 *b, int size, u8 *p, int l, tunnelidt t, sessionidt s, u16 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, session[s].ip, 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;
-}

 
 

-// find a PPP option, returns point to option, or 0 if not found
-u8 *findppp(u8 *b, u8 mtype)
-{
-       u16 l = ntohs(*(u16 *) (b + 2));
-       if (l < 4)
-               return 0;
-       b += 4;
-       l -= 4;
-       while (l)
-       {
-               if (l < b[1] || !b[1])
-                       return 0;               // faulty
-               if (*b == mtype)
-                       return b;
-               l -= b[1];
-               b += b[1];
-       }
-       return 0;
+       return b;

 }
 
 }
 

-// Send initial LCP ConfigReq
+// Send initial LCP ConfigReq for PAP, set magic no.

 void initlcp(tunnelidt t, sessionidt s)
 {
 void initlcp(tunnelidt t, sessionidt s)
 {

-       char b[500] = {0}, *q;
+       char b[500], *q;

 
 

-       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, t, s, PPPLCP)))

                return;
                return;

-       }
+

        LOG(4, 0, s, t, "Sending LCP ConfigReq for PAP\n");
        *q = ConfigReq;
        *(u8 *)(q + 1) = (time_now % 255) + 1; // ID
        LOG(4, 0, s, t, "Sending LCP ConfigReq for PAP\n");
        *q = ConfigReq;
        *(u8 *)(q + 1) = (time_now % 255) + 1; // ID


@@ -915,19 +956,24 @@ void initlcp(tunnelidt t, sessionidt s)
        *(u8 *)(q + 10) = 3;
        *(u8 *)(q + 11) = 4;
        *(u16 *)(q + 12) = htons(PPPPAP); // PAP
        *(u8 *)(q + 10) = 3;
        *(u8 *)(q + 11) = 4;
        *(u16 *)(q + 12) = htons(PPPPAP); // PAP

-       tunnelsend(b, 12 + 14, t);
+
+       LOG_HEX(5, "PPPLCP", q, 14);
+       tunnelsend(b, (q - b) + 14, t);

 }
 
 }
 

-// Send CCP reply
-void sendccp(tunnelidt t, sessionidt s)
+// Send CCP request for no compression
+static void initccp(tunnelidt t, sessionidt s)

 {
 {

-       char *q, b[500] = {0};
+       char b[500], *q;
+
+       if (!(q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPCCP)))
+               return;

 
 

-       q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPCCP);
+       LOG(4, 0, s, t, "Sending CCP ConfigReq for no compression\n");

        *q = ConfigReq;
        *(u8 *)(q + 1) = (time_now % 255) + 1; // ID
        *(u16 *)(q + 2) = htons(4); // Length
        *q = ConfigReq;
        *(u8 *)(q + 1) = (time_now % 255) + 1; // ID
        *(u16 *)(q + 2) = htons(4); // Length

+

        LOG_HEX(5, "PPPCCP", q, 4);
        tunnelsend(b, (q - b) + 4 , t);
 }
        LOG_HEX(5, "PPPCCP", q, 4);
        tunnelsend(b, (q - b) + 4 , t);
 }

-