cleanup packet length handling
[l2tpns.git] / l2tpns.c
index 0a5e6bc..d03ba2b 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 1.27 2004-09-19 23:26:46 fred_nerk Exp $";
+char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.38 2004-11-02 06:45:03 bodea Exp $";
 
 #include <arpa/inet.h>
 #include <assert.h>
@@ -57,7 +57,7 @@ int snoopfd = -1;             // UDP file handle for sending out intercept data
 int *radfds = NULL;            // RADIUS requests file handles
 int ifrfd = -1;                        // File descriptor for routing, etc
 time_t basetime = 0;           // base clock
-char *hostname = NULL;         // us.
+char hostname[1000] = "";      // us.
 int tunidx;                    // ifr_ifindex of tun device
 u32 sessionid = 0;             // session id for radius accounting
 int syslog_log = 0;            // are we logging to syslog
@@ -95,20 +95,20 @@ struct config_descriptt config_values[] = {
        CONFIG("debug", debug, INT),
        CONFIG("log_file", log_filename, STRING),
        CONFIG("pid_file", pid_file, STRING),
-       CONFIG("hostname", hostname, STRING),
        CONFIG("l2tp_secret", l2tpsecret, STRING),
        CONFIG("primary_dns", default_dns1, IP),
        CONFIG("secondary_dns", default_dns2, IP),
        CONFIG("save_state", save_state, BOOL),
        CONFIG("primary_radius", radiusserver[0], IP),
        CONFIG("secondary_radius", radiusserver[1], IP),
-       CONFIG("primary_radius_port",radiusport[0], SHORT),
-       CONFIG("secondary_radius_port",radiusport[1], SHORT),
+       CONFIG("primary_radius_port", radiusport[0], SHORT),
+       CONFIG("secondary_radius_port", radiusport[1], SHORT),
        CONFIG("radius_accounting", radius_accounting, BOOL),
        CONFIG("radius_secret", radiussecret, STRING),
        CONFIG("bind_address", bind_address, IP),
        CONFIG("send_garp", send_garp, BOOL),
        CONFIG("throttle_speed", rl_rate, UNSIGNED_LONG),
+       CONFIG("throttle_buckets", num_tbfs, INT),
        CONFIG("accounting_dir", accounting_dir, STRING),
        CONFIG("setuid", target_uid, INT),
        CONFIG("dump_speed", dump_speed, BOOL),
@@ -967,65 +967,48 @@ void controladd(controlt * c, tunnelidt t, sessionidt s)
 //
 // Throttle or Unthrottle a session
 //
-// Throttle the data folling through a session
-// to be no more than 'throttle' kbit/sec each way.
+// Throttle the data from/to through a session to no more than
+// 'rate_in' kbit/sec in (from user) or 'rate_out' kbit/sec out (to
+// user).
 //
-int throttle_session(sessionidt s, int throttle)
+// If either value is -1, the current value is retained for that
+// direction.
+//
+void throttle_session(sessionidt s, int rate_in, int rate_out)
 {
        if (!session[s].tunnel)
-               return 0;       // No-one home.
+               return; // No-one home.
 
        if (!*session[s].user)
-               return 0; // User not logged in
+               return; // User not logged in
 
-       if (throttle)
+       if (rate_in >= 0)
        {
-               int rate_in = throttle & 0x0000FFFF;
-               int rate_out = throttle >> 16;
-
-               if (session[s].tbf_in || session[s].tbf_out)
-               {
-                       if (throttle == session[s].throttle)
-                               return 1;
-
-                       // Currently throttled but the rate is changing.
-
+               int bytes = rate_in * 1024 / 8; // kbits to bytes
+               if (session[s].tbf_in)
                        free_tbf(session[s].tbf_in);
-                       free_tbf(session[s].tbf_out);
-               }
-
-               if (rate_in) session[s].tbf_in = new_tbf(s, rate_in * 1024 / 4, rate_in * 1024 / 8, send_ipin);
-               if (rate_out) session[s].tbf_out = new_tbf(s, rate_out * 1024 / 4, rate_out * 1024 / 8, send_ipout);
 
-               if (throttle != session[s].throttle)
-               {
-                       // Changed. Flood to slaves.
-                       session[s].throttle = throttle;
-                       cluster_send_session(s);
-               }
+               if (rate_in > 0)
+                       session[s].tbf_in = new_tbf(s, bytes * 2, bytes, send_ipin);
+               else
+                       session[s].tbf_in = 0;
 
-               return 1;
+               session[s].throttle_in = rate_in;
        }
 
-       // else Unthrottling.
-
-       if (!session[s].tbf_in && !session[s].tbf_out && !session[s].throttle)
-               return 0;
-
-       free_tbf(session[s].tbf_in);
-       session[s].tbf_in = 0;
+       if (rate_out >= 0)
+       {
+               int bytes = rate_out * 1024 / 8;
+               if (session[s].tbf_out)
+                       free_tbf(session[s].tbf_out);
 
-       free_tbf(session[s].tbf_out);
-       session[s].tbf_out = 0;
+               if (rate_out > 0)
+                       session[s].tbf_out = new_tbf(s, bytes * 2, bytes, send_ipout);
+               else
+                       session[s].tbf_out = 0;
 
-       if (throttle != session[s].throttle)
-       {
-               // Changed. Flood to slaves.
-               session[s].throttle = throttle;
-               cluster_send_session(s);
+               session[s].throttle_out = rate_out;
        }
-
-       return 0;
 }
 
 // start tidy shutdown of session
@@ -1091,16 +1074,18 @@ void sessionshutdown(sessionidt s, char *reason)
                }
                else
                        free_ip_address(s);
-
-               if (session[s].throttle)        // Unthrottle if throttled.
-                       throttle_session(s, 0);
        }
+
+       if (session[s].throttle_in || session[s].throttle_out) // Unthrottle if throttled.
+               throttle_session(s, 0, 0);
+
        {                            // Send CDN
                controlt *c = controlnew(14); // sending CDN
                control16(c, 1, 3, 1);    // result code (admin reasons - TBA make error, general error, add message
                control16(c, 14, s, 1);   // assigned session (our end)
                controladd(c, session[s].tunnel, s); // send the message
        }
+
        cluster_send_session(s);
 }
 
@@ -1159,8 +1144,6 @@ void sessionkill(sessionidt s, char *reason)
 
        log(2, 0, s, session[s].tunnel, "Kill session %d (%s): %s\n", s, session[s].user, reason);
 
-       throttle_session(s, 0);         // Force session to be un-throttle. Free'ing TBF structures.
-
        memset(&session[s], 0, sizeof(session[s]));
        session[s].tunnel = T_FREE;     // Mark it as free.
        session[s].next = sessionfree;
@@ -1578,7 +1561,7 @@ void processudp(u8 * buf, int len, struct sockaddr_in *addr)
                                case 13:    // Response
                                        // Why did they send a response? We never challenge.
                                        log(2, ntohl(addr->sin_addr.s_addr), s, t, "   received unexpected challenge response\n");
-                               break;
+                                       break;
 
                                case 14:    // assigned session
                                        asession = session[s].far = ntohs(*(u16 *) (b));
@@ -2141,7 +2124,14 @@ int regular_cleanups(void)
                                a = 0; // dead, no need to check for other actions
                        }
 
-                       if (a & CLI_SESS_SNOOP)
+                       if (a & CLI_SESS_NOSNOOP)
+                       {
+                               log(2, 0, s, session[s].tunnel, "Unsnooping session by CLI\n");
+                               session[s].snoop_ip = 0;
+                               session[s].snoop_port = 0;
+                               send++;
+                       }
+                       else if (a & CLI_SESS_SNOOP)
                        {
                                log(2, 0, s, session[s].tunnel, "Snooping session by CLI (to %s:%d)\n",
                                    inet_toa(cli_session_actions[s].snoop_ip), cli_session_actions[s].snoop_port);
@@ -2151,27 +2141,20 @@ int regular_cleanups(void)
                                send++;
                        }
 
-                       if (a & CLI_SESS_NOSNOOP)
+                       if (a & CLI_SESS_NOTHROTTLE)
                        {
-                               log(2, 0, s, session[s].tunnel, "Unsnooping session by CLI\n");
-                               session[s].snoop_ip = 0;
-                               session[s].snoop_port = 0;
+                               log(2, 0, s, session[s].tunnel, "Un-throttling session by CLI\n");
+                               throttle_session(s, 0, 0);
                                send++;
                        }
-
-                       if (a & CLI_SESS_THROTTLE)
+                       else if (a & CLI_SESS_THROTTLE)
                        {
                                log(2, 0, s, session[s].tunnel, "Throttling session by CLI (to %dkb/s up and %dkb/s down)\n",
-                                   cli_session_actions[s].throttle & 0xFFFF,
-                                   cli_session_actions[s].throttle >> 16);
+                                   cli_session_actions[s].throttle_in,
+                                   cli_session_actions[s].throttle_out);
 
-                               throttle_session(s, cli_session_actions[s].throttle);
-                       }
-
-                       if (a & CLI_SESS_NOTHROTTLE)
-                       {
-                               log(2, 0, s, session[s].tunnel, "Un-throttling session by CLI\n");
-                               throttle_session(s, 0);
+                               throttle_session(s, cli_session_actions[s].throttle_in, cli_session_actions[s].throttle_out);
+                               send++;
                        }
 
                        if (send)
@@ -2181,7 +2164,7 @@ int regular_cleanups(void)
                }
        }
 
-       if (config->accounting_dir && next_acct <= TIME)
+       if (*config->accounting_dir && next_acct <= TIME)
        {
                // Dump accounting data
                next_acct = TIME + ACCT_TIME;
@@ -2221,8 +2204,8 @@ int still_busy(void)
                return 1;
        }
 
-       // We stop waiting for radius after BUSY_WAIT_TIMEOUT 1/10th seconds
-       if (abs(TIME - start_busy_wait) > BUSY_WAIT_TIMEOUT)
+       // We stop waiting for radius after BUSY_WAIT_TIME 1/10th seconds
+       if (abs(TIME - start_busy_wait) > BUSY_WAIT_TIME)
        {
                log(1, 0, 0, 0, "Giving up waiting for RADIUS to be empty. Shutting down anyway.\n");
                return 0;
@@ -2246,11 +2229,13 @@ int still_busy(void)
        return 0;
 }
 
+static fd_set readset;
+static int readset_n = 0;
+
 // main loop - gets packets on tun or udp and processes them
 void mainloop(void)
 {
-       fd_set cr;
-       int cn, i;
+       int i;
        u8 buf[65536];
        struct timeval to;
        clockt next_cluster_ping = 0;   // send initial ping immediately
@@ -2259,29 +2244,22 @@ void mainloop(void)
        log(4, 0, 0, 0, "Beginning of main loop. udpfd=%d, tunfd=%d, cluster_sockfd=%d, controlfd=%d\n",
                        udpfd, tunfd, cluster_sockfd, controlfd);
 
-       FD_ZERO(&cr);
-       FD_SET(udpfd, &cr);
-       FD_SET(tunfd, &cr);
-       FD_SET(controlfd, &cr);
-       FD_SET(clifd, &cr);
-       if (cluster_sockfd) FD_SET(cluster_sockfd, &cr);
-       cn = udpfd;
-       if (cn < tunfd) cn = tunfd;
-       if (cn < controlfd) cn = controlfd;
-       if (cn < clifd) cn = clifd;
-       if (cn < cluster_sockfd) cn = cluster_sockfd;
-       for (i = 0; i < config->num_radfds; i++)
-       {
-               if (!radfds[i]) continue;
-               FD_SET(radfds[i], &cr);
-               if (radfds[i] > cn)
-                       cn = radfds[i];
-       }
+       FD_ZERO(&readset);
+       FD_SET(udpfd, &readset);
+       FD_SET(tunfd, &readset);
+       FD_SET(controlfd, &readset);
+       FD_SET(clifd, &readset);
+       if (cluster_sockfd) FD_SET(cluster_sockfd, &readset);
+       readset_n = udpfd;
+       if (tunfd > readset_n)          readset_n = tunfd;
+       if (controlfd > readset_n)      readset_n = controlfd;
+       if (clifd > readset_n)          readset_n = clifd;
+       if (cluster_sockfd > readset_n) readset_n = cluster_sockfd;
 
        while (!main_quit || still_busy())
        {
                fd_set r;
-               int n = cn;
+               int n = readset_n;
 #ifdef BGP
                fd_set w;
                int bgp_set[BGP_NUM_PEERS];
@@ -2293,7 +2271,7 @@ void mainloop(void)
                        update_config();
                }
 
-               memcpy(&r, &cr, sizeof(fd_set));
+               memcpy(&r, &readset, sizeof(fd_set));
                to.tv_sec = 0;
                to.tv_usec = 100000; // 1/10th of a second.
 
@@ -2325,7 +2303,8 @@ void mainloop(void)
                TIME = now();
                if (n < 0)
                {
-                       if (errno == EINTR)
+                       if (errno == EINTR ||
+                           errno == ECHILD) // EINTR was clobbered by sigchild_handler()
                                continue;
 
                        log(0, 0, 0, 0, "Error returned from select(): %s\n", strerror(errno));
@@ -2358,17 +2337,22 @@ void mainloop(void)
                                                break;
                                }
                        }
-                       for (i = 0; i < config->num_radfds; i++)
-                               if (FD_ISSET(radfds[i], &r))
-                                       processrad(buf, recv(radfds[i], buf, sizeof(buf), 0), i);
+
+                       if (config->cluster_iam_master)
+                               for (i = 0; i < config->num_radfds; i++)
+                                       if (FD_ISSET(radfds[i], &r))
+                                               processrad(buf, recv(radfds[i], buf, sizeof(buf), 0), i);
+
                        if (FD_ISSET(cluster_sockfd, &r))
                        {
                                int size;
                                size = recvfrom(cluster_sockfd, buf, sizeof(buf), MSG_WAITALL, (void *) &addr, &alen);
                                processcluster(buf, size, addr.sin_addr.s_addr);
                        }
+
                        if (FD_ISSET(controlfd, &r))
                                processcontrol(buf, recvfrom(controlfd, buf, sizeof(buf), MSG_WAITALL, (void *) &addr, &alen), &addr);
+
                        if (FD_ISSET(clifd, &r))
                        {
                                struct sockaddr_in addr;
@@ -2459,55 +2443,58 @@ void mainloop(void)
 }
 
 // Init data structures
-void initdata(void)
+void initdata(int optdebug, char *optconfig)
 {
        int i;
-       char *p;
 
-       if ((_statistics = shared_malloc(sizeof(struct Tstats))) == MAP_FAILED)
+       if (!(_statistics = shared_malloc(sizeof(struct Tstats))))
        {
                log(0, 0, 0, 0, "Error doing malloc for _statistics: %s\n", strerror(errno));
                exit(1);
        }
-       if ((config = shared_malloc(sizeof(struct configt))) == MAP_FAILED)
+       if (!(config = shared_malloc(sizeof(struct configt))))
        {
                log(0, 0, 0, 0, "Error doing malloc for configuration: %s\n", strerror(errno));
                exit(1);
        }
        memset(config, 0, sizeof(struct configt));
        time(&config->start_time);
-       strncpy(config->config_file, CONFIGFILE, sizeof(config->config_file) - 1);
-       if ((tunnel = shared_malloc(sizeof(tunnelt) * MAXTUNNEL)) == MAP_FAILED);
+       strncpy(config->config_file, optconfig, strlen(optconfig));
+       config->debug = optdebug;
+       config->num_tbfs = MAXTBFS;
+       config->rl_rate = 28; // 28kbps
+
+       if (!(tunnel = shared_malloc(sizeof(tunnelt) * MAXTUNNEL)))
        {
                log(0, 0, 0, 0, "Error doing malloc for tunnels: %s\n", strerror(errno));
                exit(1);
        }
-       if ((session = shared_malloc(sizeof(sessiont) * MAXSESSION)) == MAP_FAILED)
+       if (!(session = shared_malloc(sizeof(sessiont) * MAXSESSION)))
        {
                log(0, 0, 0, 0, "Error doing malloc for sessions: %s\n", strerror(errno));
                exit(1);
        }
 
-       if ((sess_count = shared_malloc(sizeof(sessioncountt) * MAXSESSION)) == MAP_FAILED)
+       if (!(sess_count = shared_malloc(sizeof(sessioncountt) * MAXSESSION)))
        {
                log(0, 0, 0, 0, "Error doing malloc for sessions_count: %s\n", strerror(errno));
                exit(1);
        }
 
-       if ((radius = shared_malloc(sizeof(radiust) * MAXRADIUS)) == MAP_FAILED)
+       if (!(radius = shared_malloc(sizeof(radiust) * MAXRADIUS)))
        {
                log(0, 0, 0, 0, "Error doing malloc for radius: %s\n", strerror(errno));
                exit(1);
        }
 
-       if ((ip_address_pool = shared_malloc(sizeof(ippoolt) * MAXIPPOOL)) == MAP_FAILED)
+       if (!(ip_address_pool = shared_malloc(sizeof(ippoolt) * MAXIPPOOL)))
        {
                log(0, 0, 0, 0, "Error doing malloc for ip_address_pool: %s\n", strerror(errno));
                exit(1);
        }
 
 #ifdef RINGBUFFER
-       if ((ringbuffer = shared_malloc(sizeof(struct Tringbuffer))) == MAP_FAILED)
+       if (!(ringbuffer = shared_malloc(sizeof(struct Tringbuffer))))
        {
                log(0, 0, 0, 0, "Error doing malloc for ringbuffer: %s\n", strerror(errno));
                exit(1);
@@ -2515,16 +2502,14 @@ void initdata(void)
        memset(ringbuffer, 0, sizeof(struct Tringbuffer));
 #endif
 
-       if ((cli_session_actions = shared_malloc(sizeof(struct cli_session_actions) * MAXSESSION))
-                       == MAP_FAILED)
+       if (!(cli_session_actions = shared_malloc(sizeof(struct cli_session_actions) * MAXSESSION)))
        {
                log(0, 0, 0, 0, "Error doing malloc for cli session actions: %s\n", strerror(errno));
                exit(1);
        }
        memset(cli_session_actions, 0, sizeof(struct cli_session_actions) * MAXSESSION);
 
-       if ((cli_tunnel_actions = shared_malloc(sizeof(struct cli_tunnel_actions) * MAXSESSION))
-                       == MAP_FAILED)
+       if (!(cli_tunnel_actions = shared_malloc(sizeof(struct cli_tunnel_actions) * MAXSESSION)))
        {
                log(0, 0, 0, 0, "Error doing malloc for cli tunnel actions: %s\n", strerror(errno));
                exit(1);
@@ -2549,15 +2534,18 @@ void initdata(void)
        for (i = 1; i < MAXTUNNEL- 1; i++)
                tunnel[i].state = TUNNELUNDEF;  // mark it as not filled in.
 
-       // Grab my hostname unless it's been specified
-       gethostname(config->hostname, sizeof(config->hostname));
-       if ((p = strchr(config->hostname, '.'))) *p = 0;
-       hostname = config->hostname;
+       if (!*hostname)
+       {
+               char *p;
+               // Grab my hostname unless it's been specified
+               gethostname(hostname, sizeof(hostname));
+               if ((p = strchr(hostname, '.'))) *p = 0;
+       }
 
        _statistics->start_time = _statistics->last_reset = time(NULL);
 
 #ifdef BGP
-       if ((bgp_peers = shared_malloc(sizeof(struct bgp_peer) * BGP_NUM_PEERS)) == MAP_FAILED)
+       if (!(bgp_peers = shared_malloc(sizeof(struct bgp_peer) * BGP_NUM_PEERS)))
        {
                log(0, 0, 0, 0, "Error doing malloc for bgp: %s\n", strerror(errno));
                exit(1);
@@ -2867,7 +2855,7 @@ void dump_acct_info()
 
        for (i = 0; i < MAXSESSION; i++)
        {
-               if (!session[i].opened || !session[i].ip || !session[i].cin || !session[i].cout || !*session[i].user || session[i].walled_garden)
+               if (!session[i].opened || !session[i].ip || !(session[i].cin || session[i].cout) || !*session[i].user || session[i].walled_garden)
                        continue;
                if (!f)
                {
@@ -2890,11 +2878,11 @@ void dump_acct_info()
 
                log(4, 0, 0, 0, "Dumping accounting information for %s\n", session[i].user);
                fprintf(f, "%s %s %d %u %u\n",
-                       session[i].user,                // username
-                       inet_toa(htonl(session[i].ip)), // ip
-                       (session[i].throttle) ? 2 : 1,  // qos
-                       (u32)session[i].cin,            // uptxoctets
-                       (u32)session[i].cout);          // downrxoctets
+                       session[i].user,                                                // username
+                       inet_toa(htonl(session[i].ip)),                                 // ip
+                       (session[i].throttle_in || session[i].throttle_out) ? 2 : 1,    // qos
+                       (u32)session[i].cin,                                            // uptxoctets
+                       (u32)session[i].cout);                                          // downrxoctets
 
                session[i].pin = session[i].cin = 0;
                session[i].pout = session[i].cout = 0;
@@ -2909,13 +2897,14 @@ int main(int argc, char *argv[])
 {
        int o;
        int optdebug = 0;
+       char *optconfig = CONFIGFILE;
 
        _program_name = strdup(argv[0]);
 
        time(&basetime);             // start clock
 
        // scan args
-       while ((o = getopt(argc, argv, "vc:h:a:")) >= 0)
+       while ((o = getopt(argc, argv, "dvc:h:")) >= 0)
        {
                switch (o)
                {
@@ -2927,10 +2916,12 @@ int main(int argc, char *argv[])
                        case 'v':
                                optdebug++;
                                break;
+                       case 'c':
+                               optconfig = optarg;
+                               break;
                        case 'h':
                                snprintf(hostname, sizeof(hostname), "%s", optarg);
                                break;
-                       case '?':
                        default:
                                printf("Args are:\n"
                                       "\t-d\tDetach from terminal\n"
@@ -2952,13 +2943,11 @@ int main(int argc, char *argv[])
 
        initiptables();
        initplugins();
-       initdata();
-
-       config->debug = optdebug;
+       initdata(optdebug, optconfig);
 
-       init_tbf();
-       init_cli();
+       init_cli(hostname);
        read_config_file();
+       init_tbf(config->num_tbfs);
 
        log(0, 0, 0, 0, "L2TPNS version " VERSION "\n");
        log(0, 0, 0, 0, "Copyright (c) 2003, 2004 Optus Internet Engineering\n");
@@ -3529,7 +3518,6 @@ int sessionsetup(tunnelidt t, sessionidt s)
 
        CSTAT(call_sessionsetup);
 
-
        log(3, session[s].ip, s, t, "Doing session setup for session\n");
 
        if (!session[s].ip || session[s].ip == 0xFFFFFFFE)
@@ -3539,7 +3527,11 @@ int sessionsetup(tunnelidt t, sessionidt s)
                        log(3, 0, s, t, "   No IP allocated. Assigned %s from pool\n",
                                        inet_toa(htonl(session[s].ip)));
                else
+               {
                        log(0, 0, s, t, "   No IP allocated. The IP address pool is FULL!\n");
+                       sessionshutdown(s, "No IP addresses available");
+                       return 0;
+               }
        }
 
 
@@ -3588,10 +3580,9 @@ int sessionsetup(tunnelidt t, sessionidt s)
                run_plugins(PLUGIN_NEW_SESSION, &data);
        }
 
-       // Force throttling on or off (Actually : refresh the current throttling status)
-       // This has the advantage of cleaning up after another throttled user who may have left
-       // firewall rules lying around
-       throttle_session(s, session[s].throttle);
+       // Allocate TBFs if throttled
+       if (session[s].throttle_in || session[s].throttle_out)
+               throttle_session(s, session[s].throttle_in, session[s].throttle_out);
 
        session[s].last_packet = time_now;
 
@@ -3680,6 +3671,12 @@ int load_session(sessionidt s, sessiont *new)
                                        // for walking the sessions to forward byte counts to the master.
                config->cluster_highest_sessionid = s;
 
+       // TEMP: old session struct used a u32 to define the throttle
+       // speed for both up/down, new uses a u16 for each.  Deal with
+       // sessions from an old master for migration.
+       if (new->throttle_out == 0 && new->tbf_out)
+               new->throttle_out = new->throttle_in;
+
        memcpy(&session[s], new, sizeof(session[s]));   // Copy over..
 
                // Do fixups into address pool.
@@ -3935,19 +3932,33 @@ tunnelidt new_tunnel()
 //
 void become_master(void)
 {
-       int s;
+       int s, i;
        run_plugins(PLUGIN_BECOME_MASTER, NULL);
 
-       for (s = 1; s <= config->cluster_highest_sessionid ; ++s)
+       // running a bunch of iptables commands is slow and can cause
+       // the master to drop tunnels on takeover--kludge around the
+       // problem by forking for the moment (note: race)
+       if (!fork_and_close())
        {
-               if (!session[s].tunnel) // Not an in-use session.
-                       continue;
+               for (s = 1; s <= config->cluster_highest_sessionid ; ++s)
+               {
+                       if (!session[s].tunnel) // Not an in-use session.
+                               continue;
 
-               run_plugins(PLUGIN_NEW_SESSION_MASTER, &session[s]);
+                       run_plugins(PLUGIN_NEW_SESSION_MASTER, &session[s]);
+               }
+               exit(0);
        }
-}
-
 
+       // add radius fds
+       for (i = 0; i < config->num_radfds; i++)
+       {
+               if (!radfds[i]) continue;
+               FD_SET(radfds[i], &readset);
+               if (radfds[i] > readset_n)
+                       readset_n = radfds[i];
+       }
+}
 
 int cmd_show_hist_idle(struct cli_def *cli, char *command, char **argv, int argc)
 {