*** empty log message ***

[l2tpns.git] / l2tpns.c

diff --git a/l2tpns.c b/l2tpns.c
index 3a7d851..e616b0d 100644 (file)
--- a/l2tpns.c
+++ b/l2tpns.c
@@ -4,7 +4,7 @@
 // Copyright (c) 2002 FireBrick (Andrews & Arnold Ltd / Watchfront Ltd) - GPL licenced
 // vim: sw=8 ts=8
 
 // Copyright (c) 2002 FireBrick (Andrews & Arnold Ltd / Watchfront Ltd) - GPL licenced
 // vim: sw=8 ts=8
 

-char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.129 2005/09/12 05:16:42 bodea Exp $";
+char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.134 2005/09/16 05:30:30 bodea Exp $";

 
 #include <arpa/inet.h>
 #include <assert.h>
 
 #include <arpa/inet.h>
 #include <assert.h>


@@ -75,6 +75,10 @@ static int syslog_log = 0;   // are we logging to syslog
 static FILE *log_stream = 0;   // file handle for direct logging (i.e. direct into file, not via syslog).
 uint32_t last_id = 0;          // Unique ID for radius accounting
 
 static FILE *log_stream = 0;   // file handle for direct logging (i.e. direct into file, not via syslog).
 uint32_t last_id = 0;          // Unique ID for radius accounting
 

+// calculated from config->l2tp_mtu
+uint16_t MRU = 0;              // PPP MRU
+uint16_t MSS = 0;              // TCP MSS
+

 struct cli_session_actions *cli_session_actions = NULL;        // Pending session changes requested by CLI
 struct cli_tunnel_actions *cli_tunnel_actions = NULL;  // Pending tunnel changes required by CLI
 
 struct cli_session_actions *cli_session_actions = NULL;        // Pending session changes requested by CLI
 struct cli_tunnel_actions *cli_tunnel_actions = NULL;  // Pending tunnel changes required by CLI
 


@@ -104,7 +108,8 @@ config_descriptt config_values[] = {
        CONFIG("log_file", log_filename, STRING),
        CONFIG("pid_file", pid_file, STRING),
        CONFIG("random_device", random_device, STRING),
        CONFIG("log_file", log_filename, STRING),
        CONFIG("pid_file", pid_file, STRING),
        CONFIG("random_device", random_device, STRING),

-       CONFIG("l2tp_secret", l2tpsecret, STRING),
+       CONFIG("l2tp_secret", l2tp_secret, STRING),
+       CONFIG("l2tp_mtu", l2tp_mtu, INT),

        CONFIG("ppp_restart_time", ppp_restart_time, INT),
        CONFIG("ppp_max_configure", ppp_max_configure, INT),
        CONFIG("ppp_max_failure", ppp_max_failure, INT),
        CONFIG("ppp_restart_time", ppp_restart_time, INT),
        CONFIG("ppp_max_configure", ppp_max_configure, INT),
        CONFIG("ppp_max_failure", ppp_max_failure, INT),


@@ -978,6 +983,50 @@ int tun_write(uint8_t * data, int size)
        return write(tunfd, data, size);
 }
 
        return write(tunfd, data, size);
 }
 

+// adjust tcp mss to avoid fragmentation (called only for tcp packets with syn set)
+void adjust_tcp_mss(sessionidt s, tunnelidt t, uint8_t *buf, int len, uint8_t *tcp)
+{
+       int d = (tcp[12] >> 4) * 4;
+       uint8_t *mss = 0;
+       uint8_t *data;
+
+       if ((tcp[13] & 0x3f) & ~(TCP_FLAG_SYN|TCP_FLAG_ACK)) // only want SYN and SYN,ACK
+               return;
+
+       if (tcp + d > buf + len) // short?
+               return;
+
+       data = tcp + d;
+       tcp += 20;
+
+       while (tcp < data)
+       {
+               if (*tcp == 2 && tcp[1] == 4) // mss option (2), length 4
+               {
+                       mss = tcp + 2;
+                       if (mss + 2 > data) return; // short?
+                       break;
+               }
+
+               if (*tcp == 0) return; // end of options
+               if (*tcp == 1 || !tcp[1]) // no op (one byte), or no length (prevent loop)
+                       tcp++;
+               else
+                       tcp += tcp[1]; // skip over option
+       }
+
+       if (!mss) return; // not found
+       if (ntohs(*(uint16_t *) mss) <= MSS) return; // mss OK
+
+       LOG(5, s, t, "TCP: %s:%u -> %s:%u SYN%s, adjusted mss from %u to %u\n",
+               fmtaddr(*(in_addr_t *)(buf + 12), 0), ntohs(*(uint16_t *)tcp),
+               fmtaddr(*(in_addr_t *)(buf + 16), 1), ntohs(*(uint16_t *)(tcp + 2)),
+               (tcp[13] & TCP_FLAG_ACK) ? ",ACK" : "",
+               ntohs(*(uint16_t *) mss), MSS);
+
+       // FIXME
+}
+

 // process outgoing (to tunnel) IP
 //
 static void processipout(uint8_t *buf, int len)
 // process outgoing (to tunnel) IP
 //
 static void processipout(uint8_t *buf, int len)


@@ -1085,6 +1134,14 @@ static void processipout(uint8_t *buf, int len)
        if (session[s].filter_out && !ip_filter(buf, len, session[s].filter_out - 1))
                return;
 
        if (session[s].filter_out && !ip_filter(buf, len, session[s].filter_out - 1))
                return;
 

+       // adjust MSS on SYN and SYN,ACK packets with options
+       if ((ntohs(*(uint16_t *) (buf + 6)) & 0x1fff) == 0 && buf[9] == IPPROTO_TCP) // first tcp fragment
+       {
+               int ihl = (buf[0] & 0xf) * 4; // length of IP header
+               if (len >= ihl + 20 && (buf[ihl + 13] & TCP_FLAG_SYN) && ((buf[ihl + 12] >> 4) > 5))
+                       adjust_tcp_mss(s, t, buf, len, buf + ihl);
+       }
+

        if (sp->tbf_out)
        {
                // Are we throttling this session?
        if (sp->tbf_out)
        {
                // Are we throttling this session?


@@ -2008,7 +2065,7 @@ void processudp(uint8_t *buf, int len, struct sockaddr_in *addr)
                                        uint16_t orig_len;
 
                                        // handle hidden AVPs
                                        uint16_t orig_len;
 
                                        // handle hidden AVPs

-                                       if (!*config->l2tpsecret)
+                                       if (!*config->l2tp_secret)

                                        {
                                                LOG(1, s, t, "Hidden AVP requested, but no L2TP secret.\n");
                                                fatal = flags;
                                        {
                                                LOG(1, s, t, "Hidden AVP requested, but no L2TP secret.\n");
                                                fatal = flags;


@@ -2381,7 +2438,7 @@ void processudp(uint8_t *buf, int len, struct sockaddr_in *addr)
                                        if (amagic == 0) amagic = time_now;
                                        session[s].magic = amagic; // set magic number
                                        session[s].l2tp_flags = aflags; // set flags received
                                        if (amagic == 0) amagic = time_now;
                                        session[s].magic = amagic; // set magic number
                                        session[s].l2tp_flags = aflags; // set flags received

-                                       session[s].mru = DEFAULT_MRU;
+                                       session[s].mru = PPPMTU; // default

                                        controlnull(t); // ack
 
                                        // start LCP
                                        controlnull(t); // ack
 
                                        // start LCP


@@ -2389,6 +2446,7 @@ void processudp(uint8_t *buf, int len, struct sockaddr_in *addr)
                                        sess_local[s].lcp.conf_sent = 1;
                                        sess_local[s].lcp.nak_sent = 0;
                                        sess_local[s].lcp_authtype = config->radius_authprefer;
                                        sess_local[s].lcp.conf_sent = 1;
                                        sess_local[s].lcp.nak_sent = 0;
                                        sess_local[s].lcp_authtype = config->radius_authprefer;

+                                       sess_local[s].ppp_mru = MRU;

                                        session[s].ppp.lcp = RequestSent;
                                        sendlcp(s, t);
 
                                        session[s].ppp.lcp = RequestSent;
                                        sendlcp(s, t);
 


@@ -2418,7 +2476,7 @@ void processudp(uint8_t *buf, int len, struct sockaddr_in *addr)
        }
        else
        {                          // data
        }
        else
        {                          // data

-               uint16_t prot;
+               uint16_t proto;

 
                LOG_HEX(5, "Receive Tunnel Data", p, l);
                if (l > 2 && p[0] == 0xFF && p[1] == 0x03)
 
                LOG_HEX(5, "Receive Tunnel Data", p, l);
                if (l > 2 && p[0] == 0xFF && p[1] == 0x03)


@@ -2434,12 +2492,12 @@ void processudp(uint8_t *buf, int len, struct sockaddr_in *addr)
                }
                if (*p & 1)
                {
                }
                if (*p & 1)
                {

-                       prot = *p++;
+                       proto = *p++;

                        l--;
                }
                else
                {
                        l--;
                }
                else
                {

-                       prot = ntohs(*(uint16_t *) p);
+                       proto = ntohs(*(uint16_t *) p);

                        p += 2;
                        l -= 2;
                }
                        p += 2;
                        l -= 2;
                }


@@ -2459,43 +2517,43 @@ void processudp(uint8_t *buf, int len, struct sockaddr_in *addr)
                        return;
                }
 
                        return;
                }
 

-               if (prot == PPPPAP)
+               if (proto == PPPPAP)

                {
                        session[s].last_packet = time_now;
                        if (!config->cluster_iam_master) { master_forward_packet(buf, len, addr->sin_addr.s_addr, addr->sin_port); return; }
                        processpap(s, t, p, l);
                }
                {
                        session[s].last_packet = time_now;
                        if (!config->cluster_iam_master) { master_forward_packet(buf, len, addr->sin_addr.s_addr, addr->sin_port); return; }
                        processpap(s, t, p, l);
                }

-               else if (prot == PPPCHAP)
+               else if (proto == PPPCHAP)

                {
                        session[s].last_packet = time_now;
                        if (!config->cluster_iam_master) { master_forward_packet(buf, len, addr->sin_addr.s_addr, addr->sin_port); return; }
                        processchap(s, t, p, l);
                }
                {
                        session[s].last_packet = time_now;
                        if (!config->cluster_iam_master) { master_forward_packet(buf, len, addr->sin_addr.s_addr, addr->sin_port); return; }
                        processchap(s, t, p, l);
                }

-               else if (prot == PPPLCP)
+               else if (proto == PPPLCP)

                {
                        session[s].last_packet = time_now;
                        if (!config->cluster_iam_master) { master_forward_packet(buf, len, addr->sin_addr.s_addr, addr->sin_port); return; }
                        processlcp(s, t, p, l);
                }
                {
                        session[s].last_packet = time_now;
                        if (!config->cluster_iam_master) { master_forward_packet(buf, len, addr->sin_addr.s_addr, addr->sin_port); return; }
                        processlcp(s, t, p, l);
                }

-               else if (prot == PPPIPCP)
+               else if (proto == PPPIPCP)

                {
                        session[s].last_packet = time_now;
                        if (!config->cluster_iam_master) { master_forward_packet(buf, len, addr->sin_addr.s_addr, addr->sin_port); return; }
                        processipcp(s, t, p, l);
                }
                {
                        session[s].last_packet = time_now;
                        if (!config->cluster_iam_master) { master_forward_packet(buf, len, addr->sin_addr.s_addr, addr->sin_port); return; }
                        processipcp(s, t, p, l);
                }

-               else if (prot == PPPIPV6CP)
+               else if (proto == PPPIPV6CP && config->ipv6_prefix.s6_addr[0])

                {
                        session[s].last_packet = time_now;
                        if (!config->cluster_iam_master) { master_forward_packet(buf, len, addr->sin_addr.s_addr, addr->sin_port); return; }
                        processipv6cp(s, t, p, l);
                }
                {
                        session[s].last_packet = time_now;
                        if (!config->cluster_iam_master) { master_forward_packet(buf, len, addr->sin_addr.s_addr, addr->sin_port); return; }
                        processipv6cp(s, t, p, l);
                }

-               else if (prot == PPPCCP)
+               else if (proto == PPPCCP)

                {
                        session[s].last_packet = time_now;
                        if (!config->cluster_iam_master) { master_forward_packet(buf, len, addr->sin_addr.s_addr, addr->sin_port); return; }
                        processccp(s, t, p, l);
                }
                {
                        session[s].last_packet = time_now;
                        if (!config->cluster_iam_master) { master_forward_packet(buf, len, addr->sin_addr.s_addr, addr->sin_port); return; }
                        processccp(s, t, p, l);
                }

-               else if (prot == PPPIP)
+               else if (proto == PPPIP)

                {
                        if (session[s].die)
                        {
                {
                        if (session[s].die)
                        {


@@ -2512,13 +2570,8 @@ void processudp(uint8_t *buf, int len, struct sockaddr_in *addr)
 
                        processipin(s, t, p, l);
                }
 
                        processipin(s, t, p, l);
                }

-               else if (prot == PPPIPV6)
+               else if (proto == PPPIPV6 && config->ipv6_prefix.s6_addr[0])

                {
                {

-                       if (!config->ipv6_prefix.s6_addr[0])
-                       {
-                               LOG(1, s, t, "IPv6 not configured; yet received IPv6 packet. Ignoring.\n");
-                               return;
-                       }

                        if (session[s].die)
                        {
                                LOG(4, s, t, "Session %d is closing.  Don't process PPP packets\n", s);
                        if (session[s].die)
                        {
                                LOG(4, s, t, "Session %d is closing.  Don't process PPP packets\n", s);


@@ -2534,10 +2587,36 @@ void processudp(uint8_t *buf, int len, struct sockaddr_in *addr)
 
                        processipv6in(s, t, p, l);
                }
 
                        processipv6in(s, t, p, l);
                }

+               else if (session[s].ppp.lcp == Opened)
+               {
+                       uint8_t buf[MAXETHER];
+                       uint8_t *q;
+                       int mru = session[s].mru;
+                       if (mru > sizeof(buf)) mru = sizeof(buf);
+
+                       l += 6;
+                       if (l > mru) l = mru;
+
+                       q = makeppp(buf, sizeof(buf), 0, 0, s, t, proto);
+                       if (!q) return;
+
+                       *q = CodeRej;
+                       *(q + 1) = ++sess_local[s].lcp_ident;
+                       *(uint16_t *)(q + 2) = 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);
+               }

                else
                {
                else
                {

-                       STAT(tunnel_rx_errors);
-                       LOG(1, s, t, "Unknown PPP protocol %04X\n", prot);
+                       LOG(2, s, t, "Unknown PPP protocol 0x%04X received in LCP %s state\n",
+                               proto, ppp_state(session[s].ppp.lcp));

                }
        }
 }
                }
        }
 }


@@ -4146,7 +4225,7 @@ static void build_chap_response(uint8_t *challenge, uint8_t id, uint16_t challen
        MD5_CTX ctx;
        *challenge_response = NULL;
 
        MD5_CTX ctx;
        *challenge_response = NULL;
 

-       if (!*config->l2tpsecret)
+       if (!*config->l2tp_secret)

        {
                LOG(0, 0, 0, "LNS requested CHAP authentication, but no l2tp secret is defined\n");
                return;
        {
                LOG(0, 0, 0, "LNS requested CHAP authentication, but no l2tp secret is defined\n");
                return;


@@ -4158,7 +4237,7 @@ static void build_chap_response(uint8_t *challenge, uint8_t id, uint16_t challen
 
        MD5_Init(&ctx);
        MD5_Update(&ctx, &id, 1);
 
        MD5_Init(&ctx);
        MD5_Update(&ctx, &id, 1);

-       MD5_Update(&ctx, config->l2tpsecret, strlen(config->l2tpsecret));
+       MD5_Update(&ctx, config->l2tp_secret, strlen(config->l2tp_secret));

        MD5_Update(&ctx, challenge, challenge_length);
        MD5_Final(*challenge_response, &ctx);
 
        MD5_Update(&ctx, challenge, challenge_length);
        MD5_Final(*challenge_response, &ctx);
 


@@ -4225,6 +4304,17 @@ static void update_config()
                setbuf(log_stream, NULL);
        }
 
                setbuf(log_stream, NULL);
        }
 

+#define L2TP_HDRS              (20+8+6+4)      // L2TP data encaptulation: ip + udp + l2tp (data) + ppp (inc hdlc)
+#define TCP_HDRS               (20+20)         // TCP encapsulation: ip + tcp
+
+       if (config->l2tp_mtu <= 0)              config->l2tp_mtu = PPPMTU;
+       else if (config->l2tp_mtu < MINMTU)     config->l2tp_mtu = MINMTU;
+       else if (config->l2tp_mtu > MAXMTU)     config->l2tp_mtu = MAXMTU;
+
+       // reset MRU/MSS globals
+       MRU = config->l2tp_mtu - L2TP_HDRS;
+       MSS = MRU - TCP_HDRS;
+

        // Update radius
        config->numradiusservers = 0;
        for (i = 0; i < MAXRADSERVER; i++)
        // Update radius
        config->numradiusservers = 0;
        for (i = 0; i < MAXRADSERVER; i++)


@@ -5123,7 +5213,7 @@ static void unhide_value(uint8_t *value, size_t len, uint16_t type, uint8_t *vec
        // Compute initial pad
        MD5_Init(&ctx);
        MD5_Update(&ctx, (unsigned char *) &m, 2);
        // Compute initial pad
        MD5_Init(&ctx);
        MD5_Update(&ctx, (unsigned char *) &m, 2);

-       MD5_Update(&ctx, config->l2tpsecret, strlen(config->l2tpsecret));
+       MD5_Update(&ctx, config->l2tp_secret, strlen(config->l2tp_secret));

        MD5_Update(&ctx, vector, vec_len);
        MD5_Final(digest, &ctx);
 
        MD5_Update(&ctx, vector, vec_len);
        MD5_Final(digest, &ctx);
 


@@ -5136,7 +5226,7 @@ static void unhide_value(uint8_t *value, size_t len, uint16_t type, uint8_t *vec
                if (d >= sizeof(digest))
                {
                        MD5_Init(&ctx);
                if (d >= sizeof(digest))
                {
                        MD5_Init(&ctx);

-                       MD5_Update(&ctx, config->l2tpsecret, strlen(config->l2tpsecret));
+                       MD5_Update(&ctx, config->l2tp_secret, strlen(config->l2tp_secret));

                        MD5_Update(&ctx, last, sizeof(digest));
                        MD5_Final(digest, &ctx);
 
                        MD5_Update(&ctx, last, sizeof(digest));
                        MD5_Final(digest, &ctx);