add Multilink support from Khaled Al Hamwi
[l2tpns.git] / l2tpns.c
index b181ca4..bd044eb 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
 
-char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.162 2006/04/23 23:18:31 bodea Exp $";
+char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.163 2006/04/27 09:53:49 bodea Exp $";
 
 #include <arpa/inet.h>
 #include <assert.h>
@@ -127,6 +127,7 @@ config_descriptt config_values[] = {
        CONFIG("radius_authtypes", radius_authtypes_s, STRING),
        CONFIG("radius_dae_port", radius_dae_port, SHORT),
        CONFIG("allow_duplicate_users", allow_duplicate_users, BOOL),
+       CONFIG("guest_account", guest_user, STRING),
        CONFIG("bind_address", bind_address, IPv4),
        CONFIG("peer_address", peer_address, IPv4),
        CONFIG("send_garp", send_garp, BOOL),
@@ -174,6 +175,8 @@ static sessiont shut_acct[8192];
 static sessionidt shut_acct_n = 0;
 
 tunnelt *tunnel = NULL;                        // Array of tunnel structures.
+bundlet *bundle = NULL;                        // Array of bundle structures.
+fragmentationt *frag = NULL;           // Array of fragmentation structures.
 sessiont *session = NULL;              // Array of session structures.
 sessionlocalt *sess_local = NULL;      // Array of local per-session counters.
 radiust *radius = NULL;                        // Array of radius structures.
@@ -203,6 +206,7 @@ static void plugins_done(void);
 static void processcontrol(uint8_t *buf, int len, struct sockaddr_in *addr, int alen, struct in_addr *local);
 static tunnelidt new_tunnel(void);
 static void unhide_value(uint8_t *value, size_t len, uint16_t type, uint8_t *vector, size_t vec_len);
+static void bundleclear(bundleidt b);
 
 // on slaves, alow BGP to withdraw cleanly before exiting
 #define QUIT_DELAY     5
@@ -1051,6 +1055,54 @@ void adjust_tcp_mss(sessionidt s, tunnelidt t, uint8_t *buf, int len, uint8_t *t
        *(uint16_t *) (tcp + 16) = htons(sum + (sum >> 16));
 }
 
+void processmpframe(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l, uint8_t extra)
+{
+       uint16_t proto;
+       if (extra) {
+               // Skip the four extra bytes
+               p += 4;
+               l -= 4;
+       }
+
+       // Process this frame
+       if (*p & 1)
+       {
+               proto = *p++;
+               l--;
+       }
+       else
+       {
+               proto = ntohs(*(uint16_t *) p);
+               p += 2;
+               l -= 2;
+       }
+       if (proto == PPPIP)
+       {
+               if (session[s].die)
+               {
+                       LOG(4, s, t, "MPPP: Session %d is closing.  Don't process PPP packets\n", s);
+                       return;              // closing session, PPP not processed
+               }
+               session[s].last_packet = time_now;
+               processipin(s, t, p, l);
+       }
+       else if (proto == PPPIPV6 && config->ipv6_prefix.s6_addr[0])
+       {
+               if (session[s].die)
+               {
+                       LOG(4, s, t, "MPPP: Session %d is closing.  Don't process PPP packets\n", s);
+                       return;              // closing session, PPP not processed
+               }
+
+               session[s].last_packet = time_now;
+               processipv6in(s, t, p, l);
+       }
+       else
+       {
+               LOG(2, s, t, "MPPP: Unsupported MP protocol 0x%04X received\n",proto);
+       }
+}
+
 // process outgoing (to tunnel) IP
 //
 static void processipout(uint8_t *buf, int len)
@@ -1063,7 +1115,8 @@ static void processipout(uint8_t *buf, int len)
        uint8_t *data = buf;    // Keep a copy of the originals.
        int size = len;
 
-       uint8_t b[MAXETHER + 20];
+       uint8_t b1[MAXETHER + 20];
+       uint8_t b2[MAXETHER + 20];
 
        CSTAT(processipout);
 
@@ -1183,13 +1236,43 @@ static void processipout(uint8_t *buf, int len)
                return;
        }
 
-       LOG(5, s, t, "Ethernet -> Tunnel (%d bytes)\n", len);
-
        // Add on L2TP header
        {
-               uint8_t *p = makeppp(b, sizeof(b), buf, len, s, t, PPPIP);
-               if (!p) return;
-               tunnelsend(b, len + (p-b), t); // send it...
+               bundleidt bid = 0;
+               if (session[s].bundle && bundle[session[s].bundle].num_of_links > 1)
+               {
+                       bid = session[s].bundle;
+                       s = bundle[bid].members[bundle[bid].current_ses = ++bundle[bid].current_ses % bundle[bid].num_of_links];
+                       LOG(4, s, t, "MPPP: (1)Session number becomes: %d\n", s);
+                       if (len > 256)
+                       {
+                               // Partition the packet to 2 fragments
+                               uint32_t frag1len = len / 2;
+                               uint32_t frag2len = len - frag1len;
+                               uint8_t *p = makeppp(b1, sizeof(b1), buf, frag1len, s, t, PPPIP, 0, bid, MP_BEGIN);
+                               uint8_t *q;
+
+                               if (!p) return;
+                               tunnelsend(b1, frag1len + (p-b1), t); // send it...
+                               s = bundle[bid].members[bundle[bid].current_ses = ++bundle[bid].current_ses % bundle[bid].num_of_links];
+                               LOG(4, s, t, "MPPP: (2)Session number becomes: %d\n", s);
+                               q = makeppp(b2, sizeof(b2), buf+frag1len, frag2len, s, t, PPPIP, 0, bid, MP_END);
+                               if (!q) return;
+                               tunnelsend(b2, frag2len + (q-b2), t); // send it...
+                       }
+                       else {
+                               // Send it as one frame
+                               uint8_t *p = makeppp(b1, sizeof(b1), buf, len, s, t, PPPIP, 0, bid, MP_BOTH_BITS);
+                               if (!p) return;
+                               tunnelsend(b1, len + (p-b1), t); // send it...
+                       }
+               }
+               else
+               {
+                       uint8_t *p = makeppp(b1, sizeof(b1), buf, len, s, t, PPPIP, 0, 0, 0);
+                       if (!p) return;
+                       tunnelsend(b1, len + (p-b1), t); // send it...
+               }
        }
 
        // Snooping this session, send it to intercept box
@@ -1273,6 +1356,12 @@ static void processipv6out(uint8_t * buf, int len)
                }
                return;
        }
+       if (session[s].bundle && bundle[session[s].bundle].num_of_links > 1)
+       {
+               bundleidt bid = session[s].bundle;
+               s = bundle[bid].members[bundle[bid].current_ses = ++bundle[bid].current_ses % bundle[bid].num_of_links];
+               LOG(3, s, session[s].tunnel, "MPPP: Session number becomes: %d\n", s);
+       }
        t = session[s].tunnel;
        sp = &session[s];
 
@@ -1298,7 +1387,7 @@ static void processipv6out(uint8_t * buf, int len)
 
        // Add on L2TP header
        {
-               uint8_t *p = makeppp(b, sizeof(b), buf, len, s, t, PPPIPV6);
+               uint8_t *p = makeppp(b, sizeof(b), buf, len, s, t, PPPIPV6, 0, 0, 0);
                if (!p) return;
                tunnelsend(b, len + (p-b), t); // send it...
        }
@@ -1350,7 +1439,7 @@ static void send_ipout(sessionidt s, uint8_t *buf, int len)
 
        // Add on L2TP header
        {
-               uint8_t *p = makeppp(b, sizeof(b), buf, len, s, t, PPPIP);
+               uint8_t *p = makeppp(b, sizeof(b), buf, len, s, t, PPPIP, 0, 0, 0);
                if (!p) return;
                tunnelsend(b, len + (p-b), t); // send it...
        }
@@ -1679,7 +1768,7 @@ void sendipcp(sessionidt s, tunnelidt t)
                session[s].unique_id = last_id;
        }
 
-       q = makeppp(buf, sizeof(buf), 0, 0, s, t, PPPIPCP);
+       q = makeppp(buf, sizeof(buf), 0, 0, s, t, PPPIPCP, 0, 0, 0);
        if (!q) return;
 
        *q = ConfigReq;
@@ -1703,7 +1792,7 @@ void sendipv6cp(sessionidt s, tunnelidt t)
        CSTAT(sendipv6cp);
        LOG(3, s, t, "IPV6CP: send ConfigReq\n");
 
-       q = makeppp(buf, sizeof(buf), 0, 0, s, t, PPPIPV6CP);
+       q = makeppp(buf, sizeof(buf), 0, 0, s, t, PPPIPV6CP, 0, 0, 0);
        if (!q) return;
 
        *q = ConfigReq;
@@ -1735,6 +1824,7 @@ static void sessionclear(sessionidt s)
 // kill a session now
 void sessionkill(sessionidt s, char *reason)
 {
+       bundleidt b;
 
        CSTAT(sessionkill);
 
@@ -1753,6 +1843,38 @@ void sessionkill(sessionidt s, char *reason)
                radiusclear(sess_local[s].radius, s); // cant send clean accounting data, session is killed
 
        LOG(2, s, session[s].tunnel, "Kill session %d (%s): %s\n", s, session[s].user, reason);
+       if ((b = session[s].bundle))
+       {
+               // This session was part of a bundle
+               bundle[b].num_of_links--;
+               LOG(3, s, 0, "MPPP: Dropping member link: %d from bundle %d\n",s,b);
+               if (bundle[b].num_of_links == 0)
+               {
+                       bundleclear(b);
+                       LOG(3, s, 0, "MPPP: Kill bundle: %d (No remaing member links)\n",b);
+               }
+               else
+               {
+                       // Adjust the members array to accomodate the new change
+                       uint8_t mem_num = 0;
+                       // It should be here num_of_links instead of num_of_links-1 (previous instruction "num_of_links--")
+                       if (bundle[b].members[bundle[b].num_of_links] != s)
+                       {
+                               uint8_t ml;
+                               for (ml = 0; ml<bundle[b].num_of_links; ml++)
+                               {
+                                       if (bundle[b].members[ml] == s)
+                                       {
+                                               mem_num = ml;
+                                               break;
+                                       }
+                               }
+                               bundle[b].members[mem_num] = bundle[b].members[bundle[b].num_of_links];
+                               LOG(3, s, 0, "MPPP: Adjusted member links array\n");
+                       }
+               }
+               cluster_send_bundle(b);
+       }
        sessionclear(s);
        cluster_send_session(s);
 }
@@ -1764,6 +1886,13 @@ static void tunnelclear(tunnelidt t)
        tunnel[t].state = TUNNELFREE;
 }
 
+static void bundleclear(bundleidt b)
+{
+       if (!b) return;
+       memset(&bundle[b], 0, sizeof(bundle[b]));
+       bundle[b].state = BUNDLEFREE;
+}
+
 // kill a tunnel now
 static void tunnelkill(tunnelidt t, char *reason)
 {
@@ -2556,6 +2685,11 @@ void processudp(uint8_t *buf, int len, struct sockaddr_in *addr)
                                        // start LCP
                                        sess_local[s].lcp_authtype = config->radius_authprefer;
                                        sess_local[s].ppp_mru = MRU;
+
+                                       // Set multilink options before sending initial LCP packet
+                                       sess_local[s].mp_mrru = 1614;
+                                       sess_local[s].mp_epdis = config->bind_address ? config->bind_address : my_address;
+
                                        sendlcp(s, t);
                                        change_state(s, lcp, RequestSent);
                                        break;
@@ -2679,6 +2813,23 @@ void processudp(uint8_t *buf, int len, struct sockaddr_in *addr)
 
                        processipin(s, t, p, l);
                }
+               else if (proto == PPPMP)
+               {
+                       if (session[s].die)
+                       {
+                               LOG(4, s, t, "Session %d is closing.  Don't process PPP packets\n", s);
+                               return;              // closing session, PPP not processed
+                       }
+
+                       session[s].last_packet = time_now;
+                       if (session[s].walled_garden && !config->cluster_iam_master)
+                       {
+                               master_forward_packet(buf, len, addr->sin_addr.s_addr, addr->sin_port);
+                               return;
+                       }
+
+                       processmpin(s, t, p, l);
+               }
                else if (proto == PPPIPV6 && config->ipv6_prefix.s6_addr[0])
                {
                        if (session[s].die)
@@ -2873,6 +3024,37 @@ static void regular_cleanups(double period)
                        continue;
                }
 
+               // check for timed out sessions
+               if (session[s].timeout)
+               {
+                       bundleidt bid = session[s].bundle;
+                       if (bid)
+                       {
+                               clockt curr_time = time_now;
+                               if (curr_time - bundle[bid].last_check >= 1)
+                               {
+                                       bundle[bid].online_time += (curr_time-bundle[bid].last_check)*bundle[bid].num_of_links;
+                                       bundle[bid].last_check = curr_time;
+                                       if (bundle[bid].online_time >= session[s].timeout)
+                                       {
+                                               int ses;
+                                               for (ses = bundle[bid].num_of_links - 1; ses >= 0; ses--)
+                                               {
+                                                       sessionshutdown(bundle[bid].members[ses], "Session timeout", CDN_ADMIN_DISC, TERM_SESSION_TIMEOUT);
+                                                       s_actions++;
+                                                       continue;
+                                               }
+                                       }
+                               }
+                       }
+                       else if (session[s].timeout <= time_now - session[s].opened)
+                       {
+                               sessionshutdown(s, "Session timeout", CDN_ADMIN_DISC, TERM_SESSION_TIMEOUT);
+                               s_actions++;
+                               continue;
+                       }
+               }
+
                // PPP timeouts
                if (sess_local[s].lcp.restart <= time_now)
                {
@@ -2999,7 +3181,7 @@ static void regular_cleanups(double period)
                {
                        uint8_t b[MAXETHER];
 
-                       uint8_t *q = makeppp(b, sizeof(b), 0, 0, s, session[s].tunnel, PPPLCP);
+                       uint8_t *q = makeppp(b, sizeof(b), 0, 0, s, session[s].tunnel, PPPLCP, 1, 0, 0);
                        if (!q) continue;
 
                        *q = EchoReq;
@@ -3714,6 +3896,16 @@ static void initdata(int optdebug, char *optconfig)
                LOG(0, 0, 0, "Error doing malloc for tunnels: %s\n", strerror(errno));
                exit(1);
        }
+       if (!(bundle = shared_malloc(sizeof(bundlet) * MAXBUNDLE)))
+       {
+               LOG(0, 0, 0, "Error doing malloc for bundles: %s\n", strerror(errno));
+               exit(1);
+       }
+       if (!(frag = shared_malloc(sizeof(fragmentationt) * MAXBUNDLE)))
+       {
+               LOG(0, 0, 0, "Error doing malloc for fragmentations: %s\n", strerror(errno));
+               exit(1);
+       }
        if (!(session = shared_malloc(sizeof(sessiont) * MAXSESSION)))
        {
                LOG(0, 0, 0, "Error doing malloc for sessions: %s\n", strerror(errno));
@@ -3760,6 +3952,7 @@ static void initdata(int optdebug, char *optconfig)
        memset(cli_tunnel_actions, 0, sizeof(struct cli_tunnel_actions) * MAXSESSION);
 
        memset(tunnel, 0, sizeof(tunnelt) * MAXTUNNEL);
+       memset(bundle, 0, sizeof(bundlet) * MAXBUNDLE);
        memset(session, 0, sizeof(sessiont) * MAXSESSION);
        memset(radius, 0, sizeof(radiust) * MAXRADIUS);
        memset(ip_address_pool, 0, sizeof(ippoolt) * MAXIPPOOL);
@@ -3777,6 +3970,10 @@ static void initdata(int optdebug, char *optconfig)
        for (i = 1; i < MAXTUNNEL; i++)
                tunnel[i].state = TUNNELUNDEF;  // mark it as not filled in.
 
+       for (i = 1; i < MAXBUNDLE; i++) {
+               bundle[i].state = BUNDLEUNDEF;
+       }
+
        if (!*hostname)
        {
                // Grab my hostname unless it's been specified
@@ -4601,6 +4798,14 @@ int sessionsetup(sessionidt s, tunnelidt t)
        // Make sure this is right
        session[s].tunnel = t;
 
+       // Join a bundle if the MRRU option is accepted
+       if (session[s].mrru > 0 && !session[s].bundle)
+       {
+               LOG(3, s, t, "This session can be part of multilink bundle\n");
+               if (join_bundle(s))
+                       cluster_send_bundle(session[s].bundle);
+       }
+
        // zap old sessions with same IP and/or username
        // Don't kill gardened sessions - doing so leads to a DoS
        // from someone who doesn't need to know the password
@@ -4617,8 +4822,21 @@ int sessionsetup(sessionidt s, tunnelidt t)
                                continue;
                        }
 
-                       if (config->allow_duplicate_users) continue;
-                       if (session[s].walled_garden || session[i].walled_garden) continue;
+                       if (config->allow_duplicate_users)
+                               continue;
+
+                       if (session[s].walled_garden || session[i].walled_garden)
+                               continue;
+
+                       // Allow duplicate sessions for guest account.
+                       if (*config->guest_user && !strcasecmp(user, config->guest_user))
+                               continue;
+
+                       // Allow duplicate sessions for multilink ones of the same bundle.
+                       if (session[s].bundle && session[i].bundle && session[s].bundle == session[i].bundle)
+                               continue;
+
+                       // Drop the new session in case of duplicate sessionss, not the old one.
                        if (!strcasecmp(user, session[i].user))
                                sessionkill(i, "Duplicate session for users");
                }