garden.c

   1 #include <string.h>
   2 #include <malloc.h>
   3 #include <stdlib.h>
   4 #include <sys/wait.h>
   5 #include <sys/types.h>
   6 #include "l2tpns.h"
   7 #include "plugin.h"
   8 #include "control.h"
   9
  10 /* walled garden */
  11
  12 char const *cvs_id = "$Id: garden.c,v 1.17 2004/11/29 02:17:17 bodea Exp $";
  13
  14 int plugin_api_version = PLUGIN_API_VERSION;
  15 static struct pluginfuncs *p = 0;
  16
  17 static int iam_master = 0;      // We're all slaves! Slaves I tell you!
  18
  19 char *up_commands[] = {
  20         "iptables -t nat -N garden >/dev/null 2>&1",                    // Create a chain that all gardened users will go through
  21         "iptables -t nat -F garden",
  22         ". " PLUGINCONF "/build-garden",                                // Populate with site-specific DNAT rules
  23         "iptables -t nat -N garden_users >/dev/null 2>&1",              // Empty chain, users added/removed by garden_session
  24         "iptables -t nat -F garden_users",
  25         "iptables -t nat -A PREROUTING -j garden_users",                // DNAT any users on the garden_users chain
  26         "sysctl -w net.ipv4.ip_conntrack_max=256000 >/dev/null",        // lots of entries
  27         NULL,
  28 };
  29
  30 char *down_commands[] = {
  31         "iptables -t nat -F PREROUTING",
  32         "iptables -t nat -F garden_users",
  33         "iptables -t nat -X garden_users",
  34         "iptables -t nat -F garden",
  35         "iptables -t nat -X garden",
  36         "rmmod iptable_nat",    // Should also remove ip_conntrack, but
  37                                 // doing so can take hours...  literally.
  38                                 // If a master is re-started as a slave,
  39                                 // either rmmod manually, or reboot.
  40         NULL,
  41 };
  42
  43 int garden_session(sessiont *s, int flag);
  44
  45 int plugin_post_auth(struct param_post_auth *data)
  46 {
  47         // Ignore if user authentication was successful
  48         if (data->auth_allowed) return PLUGIN_RET_OK;
  49
  50         p->log(3, p->get_id_by_session(data->s), data->s->tunnel, "Walled Garden allowing login\n");
  51         data->auth_allowed = 1;
  52         data->s->walled_garden = 1;
  53         return PLUGIN_RET_OK;
  54 }
  55
  56 int plugin_new_session(struct param_new_session *data)
  57 {
  58         if (!iam_master)
  59                 return PLUGIN_RET_OK;   // Slaves don't do walled garden processing.
  60
  61         if (data->s->walled_garden)
  62                 garden_session(data->s, 1);
  63
  64         return PLUGIN_RET_OK;
  65 }
  66
  67 int plugin_kill_session(struct param_new_session *data)
  68 {
  69         if (!iam_master)
  70                 return PLUGIN_RET_OK;   // Slaves don't do walled garden processing.
  71
  72         if (data->s->walled_garden)
  73                 garden_session(data->s, 0);
  74
  75         return PLUGIN_RET_OK;
  76 }
  77
  78 char *plugin_control_help[] = {
  79         "  garden USER|SID                             Put user into the walled garden",
  80         "  ungarden SID                                Release session from garden",
  81         0
  82 };
  83
  84 int plugin_control(struct param_control *data)
  85 {
  86         sessionidt session;
  87         sessiont *s = 0;
  88         int flag;
  89         char *end;
  90
  91         if (data->argc < 1)
  92                 return PLUGIN_RET_OK;
  93
  94         if (strcmp(data->argv[0], "garden") && strcmp(data->argv[0], "ungarden"))
  95                 return PLUGIN_RET_OK; // not for us
  96
  97         if (!iam_master)
  98                 return PLUGIN_RET_NOTMASTER;
  99
 100         flag = data->argv[0][0] != 'u';
 101
 102         if (data->argc != 2)
 103         {
 104                 data->response = NSCTL_RES_ERR;
 105                 data->additional = "one argument required: username or session id";
 106                 return PLUGIN_RET_STOP;
 107         }
 108
 109         if (!(session = strtol(data->argv[1], &end, 10)) || *end)
 110         {
 111                 if (flag)
 112                         session = p->get_session_by_username(data->argv[1]);
 113                 else
 114                         session = 0; // can't ungarden by username
 115         }
 116
 117         if (session)
 118                 s = p->get_session_by_id(session);
 119
 120         if (!s || !s->ip)
 121         {
 122                 data->response = NSCTL_RES_ERR;
 123                 data->additional = "session not found";
 124                 return PLUGIN_RET_STOP;
 125         }
 126
 127         if (s->walled_garden == flag)
 128         {
 129                 data->response = NSCTL_RES_ERR;
 130                 data->additional = flag ? "already in walled garden" : "not in walled garden";
 131                 return PLUGIN_RET_STOP;
 132         }
 133
 134         garden_session(s, flag);
 135         p->session_changed(session);
 136
 137         data->response = NSCTL_RES_OK;
 138         data->additional = 0;
 139
 140         return PLUGIN_RET_STOP;
 141 }
 142
 143 int plugin_become_master(void)
 144 {
 145         int i;
 146         iam_master = 1; // We just became the master. Wow!
 147
 148         for (i = 0; up_commands[i] && *up_commands[i]; i++)
 149         {
 150                 p->log(3, 0, 0, "Running %s\n", up_commands[i]);
 151                 system(up_commands[i]);
 152         }
 153
 154         return PLUGIN_RET_OK;
 155 }
 156
 157 // Called for each active session after becoming master
 158 int plugin_new_session_master(sessiont *s)
 159 {
 160         if (s->walled_garden)
 161         {
 162                 s->walled_garden = 0;
 163                 garden_session(s, 1);
 164         }
 165
 166         return PLUGIN_RET_OK;
 167 }
 168
 169 int garden_session(sessiont *s, int flag)
 170 {
 171         char cmd[2048];
 172         sessionidt sess;
 173
 174         if (!s) return 0;
 175         if (!s->opened) return 0;
 176
 177         sess = p->get_id_by_session(s);
 178         if (flag == 1)
 179         {
 180                 p->log(2, sess, s->tunnel, "Garden user %s (%s)\n", s->user, p->fmtaddr(htonl(s->ip), 0));
 181                 snprintf(cmd, sizeof(cmd), "iptables -t nat -A garden_users -s %s -j garden", p->fmtaddr(htonl(s->ip), 0));
 182                 p->log(3, sess, s->tunnel, "%s\n", cmd);
 183                 system(cmd);
 184                 s->walled_garden = 1;
 185         }
 186         else
 187         {
 188                 sessionidt other;
 189                 int count = 40;
 190
 191                 // Normal User
 192                 p->log(2, sess, s->tunnel, "Un-Garden user %s (%s)\n", s->user, p->fmtaddr(htonl(s->ip), 0));
 193                 // Kick off any duplicate usernames
 194                 // but make sure not to kick off ourself
 195                 if (s->ip && !s->die && (other = p->get_session_by_username(s->user)) && s != p->get_session_by_id(other)) {
 196                         p->sessionkill(other, "Duplicate session when user released from walled garden");
 197                 }
 198                 /* Clean up counters */
 199                 s->cin = s->cout = 0;
 200                 s->pin = s->pout = 0;
 201
 202                 snprintf(cmd, sizeof(cmd), "iptables -t nat -D garden_users -s %s -j garden", p->fmtaddr(htonl(s->ip), 0));
 203                 p->log(3, sess, s->tunnel, "%s\n", cmd);
 204                 while (--count)
 205                 {
 206                         int status = system(cmd);
 207                         if (WEXITSTATUS(status) != 0) break;
 208                 }
 209
 210                 s->walled_garden = 0;
 211
 212                 if (!s->die) {
 213                         /* OK, we're up! */
 214                         u16 r = p->radiusnew(p->get_id_by_session(s));
 215                         p->radiussend(r, RADIUSSTART);
 216                 }
 217         }
 218         s->walled_garden = flag;
 219         return 1;
 220 }
 221
 222 int plugin_init(struct pluginfuncs *funcs)
 223 {
 224         FILE *tables;
 225         int found_nat = 0;
 226
 227         if (!funcs)
 228                 return 0;
 229
 230         p = funcs;
 231
 232         if ((tables = fopen("/proc/net/ip_tables_names", "r")))
 233         {
 234                 char buf[1024];
 235                 while (fgets(buf, sizeof(buf), tables) && !found_nat)
 236                         found_nat = !strcmp(buf, "nat\n");
 237
 238                 fclose(tables);
 239         }
 240
 241         /* master killed/crashed? */
 242         if (found_nat)
 243         {
 244                 int i;
 245                 for (i = 0; down_commands[i] && *down_commands[i]; i++)
 246                 {
 247                         p->log(3, 0, 0, "Running %s\n", down_commands[i]);
 248                         system(down_commands[i]);
 249                 }
 250         }
 251
 252         return 1;
 253 }
 254
 255 void plugin_done()
 256 {
 257         int i;
 258
 259         if (!iam_master)        // Never became master. nothing to do.
 260                 return;
 261
 262         for (i = 0; down_commands[i] && *down_commands[i]; i++)
 263         {
 264                 p->log(3, 0, 0, "Running %s\n", down_commands[i]);
 265                 system(down_commands[i]);
 266         }
 267 }
 268