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fix IPCP length test to allow Terminate-Request (4 bytes)
[l2tpns.git] / ppp.c
diff --git a/ppp.c b/ppp.c
index 590a52b..578273a 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 1.81 2005/09/15 09:34:49 bodea Exp $";
+char const *cvs_id_ppp = "$Id: ppp.c,v 1.97 2006/03/27 03:01:08 bodea Exp $";
 
 #include <stdio.h>
 #include <string.h>
 
 #include <stdio.h>
 #include <string.h>
@@ -449,8 +449,7 @@ static void ppp_code_rej(sessionidt s, tunnelidt t, uint16_t proto,
 {
        uint8_t *q;
        int mru = session[s].mru;
 {
        uint8_t *q;
        int mru = session[s].mru;
-
-       if (!mru) mru = MAXMRU;
+       if (mru < MINMTU) mru = MINMTU;
        if (mru > size) mru = size;
 
        l += 4;
        if (mru > size) mru = size;
 
        l += 4;
@@ -461,7 +460,7 @@ static void ppp_code_rej(sessionidt s, tunnelidt t, uint16_t proto,
 
        *q = CodeRej;
        *(q + 1) = ++sess_local[s].lcp_ident;
 
        *q = CodeRej;
        *(q + 1) = ++sess_local[s].lcp_ident;
-       *(uint16_t *)(q + 2) = l;
+       *(uint16_t *)(q + 2) = htons(l);
        memcpy(q + 4, p, l - 4);
 
        LOG(2, s, t, "Unexpected %s code %s\n", pname, ppp_code(*p));
        memcpy(q + 4, p, l - 4);
 
        LOG(2, s, t, "Unexpected %s code %s\n", pname, ppp_code(*p));
@@ -476,7 +475,6 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 {
        uint8_t b[MAXETHER];
        uint8_t *q = NULL;
 {
        uint8_t b[MAXETHER];
        uint8_t *q = NULL;
-       uint32_t magicno = 0;
        uint16_t hl;
 
        CSTAT(processlcp);
        uint16_t hl;
 
        CSTAT(processlcp);
@@ -500,7 +498,9 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
        if (session[s].die) // going down...
                return;
 
        if (session[s].die) // going down...
                return;
 
-       LOG(*p == EchoReq ? 4 : 3, s, t, "LCP: recv %s\n", ppp_code(*p));
+       LOG((*p == EchoReq || *p == EchoReply) ? 4 : 3, s, t,
+               "LCP: recv %s\n", ppp_code(*p));
+
        if (config->debug > 3) dumplcp(p, l);
 
        if (*p == ConfigAck)
        if (config->debug > 3) dumplcp(p, l);
 
        if (*p == ConfigAck)
@@ -579,14 +579,15 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
                                case 1: // Maximum-Receive-Unit
                                        {
                                                uint16_t mru = ntohs(*(uint16_t *)(o + 2));
                                case 1: // Maximum-Receive-Unit
                                        {
                                                uint16_t mru = ntohs(*(uint16_t *)(o + 2));
-                                               if (!config->ppp_mru || mru <= config->ppp_mru)
+                                               if (mru >= MINMTU)
                                                {
                                                        session[s].mru = mru;
                                                {
                                                        session[s].mru = mru;
+                                                       cluster_send_session(s);
                                                        break;
                                                }
 
                                                LOG(3, s, t, "    Remote requesting MRU of %u.  Rejecting.\n", mru);
                                                        break;
                                                }
 
                                                LOG(3, s, t, "    Remote requesting MRU of %u.  Rejecting.\n", mru);
-                                               mru = htons(config->ppp_mru);
+                                               mru = htons(MRU);
                                                q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, (uint8_t *) &mru, sizeof(mru));
                                        }
                                        break;
                                                q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, (uint8_t *) &mru, sizeof(mru));
                                        }
                                        break;
@@ -648,11 +649,8 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
                                        }
                                        break;
 
                                        }
                                        break;
 
-                               case 5: // Magic-Number
-                                       magicno = ntohl(*(uint32_t *)(o + 2));
-                                       break;
-
                                case 4: // Quality-Protocol
                                case 4: // Quality-Protocol
+                               case 5: // Magic-Number
                                case 7: // Protocol-Field-Compression
                                case 8: // Address-And-Control-Field-Compression
                                        break;
                                case 7: // Protocol-Field-Compression
                                case 8: // Address-And-Control-Field-Compression
                                        break;
@@ -749,13 +747,13 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
                                case 1: // Maximum-Receive-Unit
                                        if (*p == ConfigNak)
                                        {
                                case 1: // Maximum-Receive-Unit
                                        if (*p == ConfigNak)
                                        {
-                                               session[s].mru = 0;
-                                               LOG(3, s, t, "    Remote requested MRU of %u; removing option\n",
-                                                       ntohs(*(uint16_t *)(o + 2)));
+                                               if (length < 4) break;
+                                               sess_local[s].ppp_mru = ntohs(*(uint16_t *)(o + 2));
+                                               LOG(3, s, t, "    Remote requested MRU of %u\n", sess_local[s].ppp_mru);
                                        }
                                        else
                                        {
                                        }
                                        else
                                        {
-                                               session[s].mru = 0;
+                                               sess_local[s].ppp_mru = 0;
                                                LOG(3, s, t, "    Remote rejected MRU negotiation\n");
                                        }
 
                                                LOG(3, s, t, "    Remote rejected MRU negotiation\n");
                                        }
 
@@ -767,14 +765,18 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 
                                        if (*p == ConfigNak)
                                        {
 
                                        if (*p == ConfigNak)
                                        {
-                                               int proto = ntohs(*(uint16_t *)(o + 2));
+                                               int proto;
+
+                                               if (length < 4) break;
+                                               proto = ntohs(*(uint16_t *)(o + 2));
+
                                                if (proto == PPPPAP)
                                                {
                                                        authtype = config->radius_authtypes & AUTHPAP;
                                                        LOG(3, s, t, "    Remote requested PAP authentication...%sing\n",
                                                                authtype ? "accept" : "reject");
                                                }
                                                if (proto == PPPPAP)
                                                {
                                                        authtype = config->radius_authtypes & AUTHPAP;
                                                        LOG(3, s, t, "    Remote requested PAP authentication...%sing\n",
                                                                authtype ? "accept" : "reject");
                                                }
-                                               else if (proto == PPPCHAP && *(o + 4) == 5)
+                                               else if (proto == PPPCHAP && length > 4 && *(o + 4) == 5)
                                                {
                                                        authtype = config->radius_authtypes & AUTHCHAP;
                                                        LOG(3, s, t, "    Remote requested CHAP authentication...%sing\n",
                                                {
                                                        authtype = config->radius_authtypes & AUTHCHAP;
                                                        LOG(3, s, t, "    Remote requested CHAP authentication...%sing\n",
@@ -794,9 +796,26 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 
                                        break;
 
 
                                        break;
 
+                               case 5: // Magic-Number
+                                       session[s].magic = 0;
+                                       if (*p == ConfigNak)
+                                       {
+                                               if (length < 6) break;
+                                               session[s].magic = ntohl(*(uint32_t *)(o + 2));
+                                       }
+
+                                       if (session[s].magic)
+                                               LOG(3, s, t, "    Remote requested magic-no %x\n", session[s].magic);
+                                       else
+                                               LOG(3, s, t, "    Remote rejected magic-no\n");
+
+                                       cluster_send_session(s);
+                                       break;
+
                                default:
                                        LOG(2, s, t, "LCP: remote sent %s for type %u?\n", ppp_code(*p), type);
                                default:
                                        LOG(2, s, t, "LCP: remote sent %s for type %u?\n", ppp_code(*p), type);
-                                       break;
+                                       sessionshutdown(s, "Unable to negotiate LCP.", 3, 0);
+                                       return;
                        }
                        x -= length;
                        o += length;
                        }
                        x -= length;
                        o += length;
@@ -917,11 +936,17 @@ static void ipcp_open(sessionidt s, tunnelidt t)
 
        change_state(s, ipcp, Opened);
 
 
        change_state(s, ipcp, Opened);
 
-       if (!session[s].walled_garden)
+       if (!(session[s].walled_garden || session[s].flags & SESSION_STARTED))
        {
                uint16_t r = radiusnew(s);
                if (r)
        {
                uint16_t r = radiusnew(s);
                if (r)
+               {
                        radiussend(r, RADIUSSTART); // send radius start
                        radiussend(r, RADIUSSTART); // send radius start
+
+                       // don't send further Start records if IPCP is restarted
+                       session[s].flags |= SESSION_STARTED;
+                       cluster_send_session(s);
+               }
        }
 
        // start IPv6 if configured and still in passive state
        }
 
        // start IPv6 if configured and still in passive state
@@ -942,7 +967,7 @@ void processipcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
        CSTAT(processipcp);
 
        LOG_HEX(5, "IPCP", p, l);
        CSTAT(processipcp);
 
        LOG_HEX(5, "IPCP", p, l);
-       if (l < 5)
+       if (l < 4)
        {
                LOG(1, s, t, "Short IPCP %d bytes\n", l);
                STAT(tunnel_rx_errors);
        {
                LOG(1, s, t, "Short IPCP %d bytes\n", l);
                STAT(tunnel_rx_errors);
@@ -999,11 +1024,13 @@ void processipcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 
                while (length > 2)
                {
 
                while (length > 2)
                {
+                       if (!o[1] || o[1] > length) return;
+
                        switch (*o)
                        {
                        case 3: // ip address
                                gotip++; // seen address
                        switch (*o)
                        {
                        case 3: // ip address
                                gotip++; // seen address
-                               if (o[1] != 6 || o[1] > length) return;
+                               if (o[1] != 6) return;
 
                                addr = htonl(session[s].ip);
                                if (memcmp(o + 2, &addr, (sizeof addr)))
 
                                addr = htonl(session[s].ip);
                                if (memcmp(o + 2, &addr, (sizeof addr)))
@@ -1020,7 +1047,7 @@ void processipcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
                                break;
 
                        case 129: // primary DNS
                                break;
 
                        case 129: // primary DNS
-                               if (o[1] != 6 || o[1] > length) return;
+                               if (o[1] != 6) return;
 
                                addr = htonl(session[s].dns1);
                                if (memcmp(o + 2, &addr, (sizeof addr)))
 
                                addr = htonl(session[s].dns1);
                                if (memcmp(o + 2, &addr, (sizeof addr)))
@@ -1032,9 +1059,9 @@ void processipcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
                                break;
 
                        case 131: // secondary DNS
                                break;
 
                        case 131: // secondary DNS
-                               if (o[1] != 6 || o[1] > length) return;
+                               if (o[1] != 6) return;
 
 
-                               addr = htonl(session[s].dns1);
+                               addr = htonl(session[s].dns2);
                                if (memcmp(o + 2, &addr, sizeof(addr)))
                                {
                                        q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
                                if (memcmp(o + 2, &addr, sizeof(addr)))
                                {
                                        q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
@@ -1224,11 +1251,13 @@ void processipv6cp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 
                while (length > 2)
                {
 
                while (length > 2)
                {
+                       if (!o[1] || o[1] > length) return;
+
                        switch (*o)
                        {
                        case 1: // interface identifier
                                gotip++; // seen address
                        switch (*o)
                        {
                        case 1: // interface identifier
                                gotip++; // seen address
-                               if (o[1] != 10 || o[1] > length) return;
+                               if (o[1] != 10) return;
 
                                *(uint32_t *) ident = htonl(session[s].ip);
                                *(uint32_t *) (ident + 4) = 0;
 
                                *(uint32_t *) ident = htonl(session[s].ip);
                                *(uint32_t *) (ident + 4) = 0;
@@ -1349,6 +1378,13 @@ void processipin(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 
        LOG_HEX(5, "IP", p, l);
 
 
        LOG_HEX(5, "IP", p, l);
 
+       if (l < 20)
+       {
+               LOG(1, s, t, "IP packet too short %d\n", l);
+               STAT(tunnel_rx_errors);
+               return ;
+       }
+
        ip = ntohl(*(uint32_t *)(p + 12));
 
        if (l > MAXETHER)
        ip = ntohl(*(uint32_t *)(p + 12));
 
        if (l > MAXETHER)
@@ -1372,6 +1408,14 @@ void processipin(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
        if (session[s].filter_in && !ip_filter(p, l, session[s].filter_in - 1))
                return;
 
        if (session[s].filter_in && !ip_filter(p, l, session[s].filter_in - 1))
                return;
 
+       // adjust MSS on SYN and SYN,ACK packets with options
+       if ((ntohs(*(uint16_t *) (p + 6)) & 0x1fff) == 0 && p[9] == IPPROTO_TCP) // first tcp fragment
+       {
+               int ihl = (p[0] & 0xf) * 4; // length of IP header
+               if (l >= ihl + 20 && (p[ihl + 13] & TCP_FLAG_SYN) && ((p[ihl + 12] >> 4) > 5))
+                       adjust_tcp_mss(s, t, p, l, p + ihl);
+       }
+
        // Add on the tun header
        p -= 4;
        *(uint32_t *) p = htonl(PKTIP);
        // Add on the tun header
        p -= 4;
        *(uint32_t *) p = htonl(PKTIP);
@@ -1730,15 +1774,12 @@ void sendchap(sessionidt s, tunnelidt t)
 }
 
 // fill in a L2TP message with a PPP frame,
 }
 
 // fill in a L2TP message with a PPP frame,
-// copies existing PPP message and changes magic number if seen
 // returns start of PPP frame
 uint8_t *makeppp(uint8_t *b, int size, uint8_t *p, int l, sessionidt s, tunnelidt t, uint16_t mtype)
 {
        if (size < 12) // Need more space than this!!
        {
 // returns start of PPP frame
 uint8_t *makeppp(uint8_t *b, int size, uint8_t *p, int l, sessionidt s, tunnelidt t, uint16_t mtype)
 {
        if (size < 12) // Need more space than this!!
        {
-               static int backtrace_count = 0;
                LOG(0, s, t, "makeppp buffer too small for L2TP header (size=%d)\n", size);
                LOG(0, s, t, "makeppp buffer too small for L2TP header (size=%d)\n", size);
-               log_backtrace(backtrace_count, 5)
                return NULL;
        }
 
                return NULL;
        }
 
@@ -1746,12 +1787,12 @@ uint8_t *makeppp(uint8_t *b, int size, uint8_t *p, int l, sessionidt s, tunnelid
        *(uint16_t *) (b + 2) = htons(tunnel[t].far); // tunnel
        *(uint16_t *) (b + 4) = htons(session[s].far); // session
        b += 6;
        *(uint16_t *) (b + 2) = htons(tunnel[t].far); // tunnel
        *(uint16_t *) (b + 4) = htons(session[s].far); // session
        b += 6;
-       if (mtype == PPPLCP || !(session[s].l2tp_flags & SESSIONACFC))
+       if (mtype == PPPLCP || !(session[s].flags & SESSION_ACFC))
        {
                *(uint16_t *) b = htons(0xFF03); // HDLC header
                b += 2;
        }
        {
                *(uint16_t *) b = htons(0xFF03); // HDLC header
                b += 2;
        }
-       if (mtype < 0x100 && session[s].l2tp_flags & SESSIONPFC)
+       if (mtype < 0x100 && session[s].flags & SESSION_PFC)
                *b++ = mtype;
        else
        {
                *b++ = mtype;
        else
        {
@@ -1761,9 +1802,7 @@ uint8_t *makeppp(uint8_t *b, int size, uint8_t *p, int l, sessionidt s, tunnelid
 
        if (l + 12 > size)
        {
 
        if (l + 12 > size)
        {
-               static int backtrace_count = 0;
                LOG(2, s, t, "makeppp would overflow buffer (size=%d, header+payload=%d)\n", size, l + 12);
                LOG(2, s, t, "makeppp would overflow buffer (size=%d, header+payload=%d)\n", size, l + 12);
-               log_backtrace(backtrace_count, 5)
                return NULL;
        }
 
                return NULL;
        }
 
@@ -1799,7 +1838,7 @@ static int add_lcp_auth(uint8_t *b, int size, int authtype)
        return len;
 }
 
        return len;
 }
 
-// Send initial LCP ConfigReq for MRU, authentication type and magic no
+// Send LCP ConfigReq for MRU, authentication type and magic no
 void sendlcp(sessionidt s, tunnelidt t)
 {
        uint8_t b[500], *q, *l;
 void sendlcp(sessionidt s, tunnelidt t)
 {
        uint8_t b[500], *q, *l;
@@ -1819,18 +1858,21 @@ void sendlcp(sessionidt s, tunnelidt t)
 
        l += 2; //Save space for length
 
 
        l += 2; //Save space for length
 
-       if (session[s].mru)
+       if (sess_local[s].ppp_mru)
        {
                *l++ = 1; *l++ = 4; // Maximum-Receive-Unit (length 4)
        {
                *l++ = 1; *l++ = 4; // Maximum-Receive-Unit (length 4)
-               *(uint16_t *) l = htons(session[s].mru); l += 2;
+               *(uint16_t *) l = htons(sess_local[s].ppp_mru); l += 2;
        }
 
        if (authtype)
                l += add_lcp_auth(l, sizeof(b) - (l - b), authtype);
 
        }
 
        if (authtype)
                l += add_lcp_auth(l, sizeof(b) - (l - b), authtype);
 
-       *l++ = 5; *l++ = 6; // Magic-Number (length 6)
-       *(uint32_t *) l = htonl(session[s].magic);
-       l += 4;
+       if (session[s].magic)
+       {
+               *l++ = 5; *l++ = 6; // Magic-Number (length 6)
+               *(uint32_t *) l = htonl(session[s].magic);
+               l += 4;
+       }
 
        *(uint16_t *)(q + 2) = htons(l - q); // Length
 
 
        *(uint16_t *)(q + 2) = htons(l - q); // Length
 
@@ -1838,6 +1880,7 @@ void sendlcp(sessionidt s, tunnelidt t)
        if (config->debug > 3) dumplcp(q, l - q);
 
        tunnelsend(b, (l - b), t);
        if (config->debug > 3) dumplcp(q, l - q);
 
        tunnelsend(b, (l - b), t);
+       restart_timer(s, lcp);
 }
 
 // Send CCP request for no compression
 }
 
 // Send CCP request for no compression
@@ -1856,4 +1899,35 @@ void sendccp(sessionidt s, tunnelidt t)
 
        LOG_HEX(5, "PPPCCP", q, 4);
        tunnelsend(b, (q - b) + 4 , t);
 
        LOG_HEX(5, "PPPCCP", q, 4);
        tunnelsend(b, (q - b) + 4 , t);
+       restart_timer(s, ccp);
+}
+
+// Reject unknown/unconfigured protocols
+void protoreject(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l, uint16_t proto)
+{
+
+       uint8_t buf[MAXETHER];
+       uint8_t *q;
+       int mru = session[s].mru;
+       if (mru < MINMTU) mru = MINMTU;
+       if (mru > sizeof(buf)) mru = sizeof(buf);
+
+       l += 6;
+       if (l > mru) l = mru;
+
+       q = makeppp(buf, sizeof(buf), 0, 0, s, t, PPPLCP);
+       if (!q) return;
+
+       *q = ProtocolRej;
+       *(q + 1) = ++sess_local[s].lcp_ident;
+       *(uint16_t *)(q + 2) = htons(l);
+       *(uint16_t *)(q + 4) = htons(proto);
+       memcpy(q + 6, p, l - 6);
+
+       if (proto == PPPIPV6CP)
+               LOG(3, s, t, "LCP: send ProtocolRej (IPV6CP: not configured)\n");
+       else
+               LOG(2, s, t, "LCP: sent ProtocolRej (0x%04X: unsupported)\n", proto);
+
+       tunnelsend(buf, l + (q - buf), 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"