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[l2tpns.git] / ppp.c
diff --git a/ppp.c b/ppp.c
index a169512..9467ef1 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 1.27 2004-11-18 13:15:28 bodea Exp $";
+char const *cvs_id_ppp = "$Id: ppp.c,v 1.28 2004-11-25 02:45:27 bodea Exp $";
 
 #include <stdio.h>
 #include <string.h>
 
 #include <stdio.h>
 #include <string.h>
@@ -23,8 +23,6 @@ extern u32 eth_tx;
 extern time_t time_now;
 extern struct configt *config;
 
 extern time_t time_now;
 extern struct configt *config;
 
-static void sendccp(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 +73,8 @@ 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
@@ -384,14 +380,17 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
                                        LOG(2, session[s].ip, s, t, "    Remote requesting asyncmap.  Rejecting.\n");
                                        if (!response)
                                        {
                                        LOG(2, session[s].ip, s, t, "    Remote requesting asyncmap.  Rejecting.\n");
                                        if (!response)
                                        {
-                                               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 = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP);
+                                               if (!q) break;
                                                response = *q++ = ConfigNak;
                                        }
                                                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++ = type;
                                        *q++ = 6;
                                        memset(q, 0, 4); // asyncmap 0
@@ -417,14 +416,17 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
 
                                                if (!response)
                                                {
 
                                                if (!response)
                                                {
-                                                       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 = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP);
+                                                       if (!q) break;
                                                        response = *q++ = ConfigNak;
                                                }
                                                        response = *q++ = ConfigNak;
                                                }
+
+                                               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;
                                                memcpy(q, o, length);
                                                *(u16 *)(q += 2) = htons(PPPPAP); // NAK -> Use PAP instead
                                                q += length;
@@ -444,15 +446,17 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
                                        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
                                        {
                                        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), p, l, t, s, PPPLCP);
-                                               if (!q)
-                                               {
-                                                       LOG(2, session[s].ip, s, t, " Failed to send packet.\n");
-                                                       break;
-                                               }
+                                               q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP);
+                                               if (!q) return;
                                                response = *q++ = ConfigRej;
                                        }
 
                                                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;
+                                       }
+
                                        memcpy(q, o, length);
                                        q += length;
                        }
                                        memcpy(q, o, length);
                                        q += length;
                        }
@@ -464,11 +468,7 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
                {
                        // Send back a ConfigAck
                        q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
                {
                        // Send back a ConfigAck
                        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;
-                       }
+                       if (!q) return;
                        response = *q = ConfigAck;
                }
 
                        response = *q = ConfigAck;
                }
 
@@ -480,22 +480,18 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
        }
        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)
        {
@@ -503,15 +499,11 @@ 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)
@@ -527,11 +519,7 @@ 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);
        }
@@ -639,10 +627,8 @@ 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])
@@ -696,10 +682,8 @@ 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
                }
        }
@@ -814,41 +798,40 @@ void send_ipin(sessionidt s, u8 *buf, int len)
 // 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))
-       {
-               LOG(1, 0, s, t, "Unexpected CCP request code %d\n", *p);
-               STAT(tunnel_rx_errors);
-               return ;
-       }
-       // reject
+       switch (l > 1 ? *p : 0)
        {
        {
-               u8 b[MAXCONTROL];
-               u8 *q;
-               if (*p == ConfigReq)
-               {
-                       if (l < 6)
-                       {
-                               *p = ConfigAck;         // accept no compression
-                       }
-                       else
-                       {
-                               *p = ConfigRej;         // reject
-                               sendccp(t, s);
-                       }
-               }
+       case ConfigReq:
+               if (l < 6)
+                       *p = ConfigAck;         // accept no compression
                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
+                       *p = ConfigRej;         // reject
+
+               break;
+
+       case TerminateReq:
+               *p = TerminateAck;
+               break;
+
+       default:
+               if (l > 1)
+                       LOG(1, 0, s, t, "Unexpected CCP request code %d\n", *p);
+               else
+                       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
@@ -886,11 +869,8 @@ 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
@@ -905,8 +885,13 @@ 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
@@ -925,12 +910,17 @@ 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;
 }
 
        return b;
 }
 
@@ -939,12 +929,9 @@ void initlcp(tunnelidt t, sessionidt s)
 {
        char b[500] = {0}, *q;
 
 {
        char b[500] = {0}, *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
@@ -957,17 +944,3 @@ void initlcp(tunnelidt t, sessionidt s)
        *(u16 *)(q + 12) = htons(PPPPAP); // PAP
        tunnelsend(b, 12 + 14, t);
 }
        *(u16 *)(q + 12) = htons(PPPPAP); // PAP
        tunnelsend(b, 12 + 14, t);
 }
-
-// Send CCP reply
-static void sendccp(tunnelidt t, sessionidt s)
-{
-       char *q, b[500] = {0};
-
-       q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPCCP);
-       *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);
-}
-
for cloning use: "git clone git://git.sameswireless.fr/l2tpns.git" ; For add to your sources.list: "deb http://package.sameswifi.fr/ jessie main"