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 1.24 2005/10/11 09:04:53 bodea Exp $";
  13
  14 int plugin_api_version = PLUGIN_API_VERSION;
  15 static struct pluginfuncs *f = 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=512000 >/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 #define F_UNGARDEN      0
  44 #define F_GARDEN        1
  45 #define F_CLEANUP       2
  46
  47 int garden_session(sessiont *s, int flag, char *newuser);
  48
  49 int plugin_post_auth(struct param_post_auth *data)
  50 {
  51     // Ignore if user authentication was successful
  52     if (data->auth_allowed)
  53         return PLUGIN_RET_OK;
  54
  55     f->log(3, f->get_id_by_session(data->s), data->s->tunnel,
  56         "Walled Garden allowing login\n");
  57
  58     data->auth_allowed = 1;
  59     data->s->walled_garden = 1;
  60     return PLUGIN_RET_OK;
  61 }
  62
  63 int plugin_new_session(struct param_new_session *data)
  64 {
  65     if (!iam_master)
  66         return PLUGIN_RET_OK;   // Slaves don't do walled garden processing.
  67
  68     if (data->s->walled_garden)
  69         garden_session(data->s, F_GARDEN, 0);
  70
  71     return PLUGIN_RET_OK;
  72 }
  73
  74 int plugin_kill_session(struct param_new_session *data)
  75 {
  76     if (!iam_master)
  77         return PLUGIN_RET_OK;   // Slaves don't do walled garden processing.
  78
  79     if (data->s->walled_garden)
  80         garden_session(data->s, F_CLEANUP, 0);
  81
  82     return PLUGIN_RET_OK;
  83 }
  84
  85 char *plugin_control_help[] = {
  86     "  garden USER|SID                             Put user into the walled garden",
  87     "  ungarden SID [USER]                         Release session from garden",
  88     0
  89 };
  90
  91 int plugin_control(struct param_control *data)
  92 {
  93     sessionidt session;
  94     sessiont *s = 0;
  95     int flag;
  96     char *end;
  97
  98     if (data->argc < 1)
  99         return PLUGIN_RET_OK;
 100
 101     if (strcmp(data->argv[0], "garden") && strcmp(data->argv[0], "ungarden"))
 102         return PLUGIN_RET_OK; // not for us
 103
 104     if (!iam_master)
 105         return PLUGIN_RET_NOTMASTER;
 106
 107     flag = data->argv[0][0] == 'g' ? F_GARDEN : F_UNGARDEN;
 108
 109     if (data->argc < 2 || data->argc > 3 || (data->argc > 2 && flag == F_GARDEN))
 110     {
 111         data->response = NSCTL_RES_ERR;
 112         data->additional = flag == F_GARDEN
 113             ? "requires username or session id"
 114             : "requires session id and optional username";
 115
 116         return PLUGIN_RET_STOP;
 117     }
 118
 119     if (!(session = strtol(data->argv[1], &end, 10)) || *end)
 120     {
 121         if (flag)
 122             session = f->get_session_by_username(data->argv[1]);
 123         else
 124             session = 0; // can't ungarden by username
 125     }
 126
 127     if (session)
 128         s = f->get_session_by_id(session);
 129
 130     if (!s || !s->ip)
 131     {
 132         data->response = NSCTL_RES_ERR;
 133         data->additional = "session not found";
 134         return PLUGIN_RET_STOP;
 135     }
 136
 137     if (s->walled_garden == flag)
 138     {
 139         data->response = NSCTL_RES_ERR;
 140         data->additional = flag ? "already in walled garden" : "not in walled garden";
 141         return PLUGIN_RET_STOP;
 142     }
 143
 144     garden_session(s, flag, data->argc > 2 ? data->argv[2] : 0);
 145     f->session_changed(session);
 146
 147     data->response = NSCTL_RES_OK;
 148     data->additional = 0;
 149
 150     return PLUGIN_RET_STOP;
 151 }
 152
 153 int plugin_become_master(void)
 154 {
 155     int i;
 156     iam_master = 1;     // We just became the master. Wow!
 157
 158     for (i = 0; up_commands[i] && *up_commands[i]; i++)
 159     {
 160         f->log(3, 0, 0, "Running %s\n", up_commands[i]);
 161         system(up_commands[i]);
 162     }
 163
 164     return PLUGIN_RET_OK;
 165 }
 166
 167 // Called for each active session after becoming master
 168 int plugin_new_session_master(sessiont *s)
 169 {
 170     if (s->walled_garden)
 171         garden_session(s, F_GARDEN, 0);
 172
 173     return PLUGIN_RET_OK;
 174 }
 175
 176 int garden_session(sessiont *s, int flag, char *newuser)
 177 {
 178     char cmd[2048];
 179     sessionidt sess;
 180
 181     if (!s) return 0;
 182     if (!s->opened) return 0;
 183
 184     sess = f->get_id_by_session(s);
 185     if (flag == F_GARDEN)
 186     {
 187         f->log(2, sess, s->tunnel, "Garden user %s (%s)\n", s->user,
 188             f->fmtaddr(htonl(s->ip), 0));
 189
 190         snprintf(cmd, sizeof(cmd),
 191             "iptables -t nat -A garden_users -s %s -j garden",
 192             f->fmtaddr(htonl(s->ip), 0));
 193
 194         f->log(3, sess, s->tunnel, "%s\n", cmd);
 195         system(cmd);
 196         s->walled_garden = 1;
 197     }
 198     else
 199     {
 200         sessionidt other;
 201         int count = 40;
 202
 203         // Normal User
 204         f->log(2, sess, s->tunnel, "Un-Garden user %s (%s)\n", s->user, f->fmtaddr(htonl(s->ip), 0));
 205         if (newuser)
 206         {
 207             snprintf(s->user, MAXUSER, "%s", newuser);
 208             f->log(2, sess, s->tunnel, "  Setting username to %s\n", s->user);
 209         }
 210
 211         // Kick off any duplicate usernames
 212         // but make sure not to kick off ourself
 213         if (s->ip && !s->die && (other = f->get_session_by_username(s->user)) &&
 214             s != f->get_session_by_id(other))
 215         {
 216             f->sessionkill(other,
 217                 "Duplicate session when user released from walled garden");
 218         }
 219
 220         /* Clean up counters */
 221         s->pin = s->pout = 0;
 222         s->cin = s->cout = 0;
 223         s->cin_delta = s->cout_delta = 0;
 224         s->cin_wrap = s->cout_wrap = 0;
 225
 226         snprintf(cmd, sizeof(cmd),
 227             "iptables -t nat -D garden_users -s %s -j garden",
 228             f->fmtaddr(htonl(s->ip), 0));
 229
 230         f->log(3, sess, s->tunnel, "%s\n", cmd);
 231         while (--count)
 232         {
 233             int status = system(cmd);
 234             if (WEXITSTATUS(status) != 0) break;
 235         }
 236
 237         s->walled_garden = 0;
 238
 239         if (flag != F_CLEANUP)
 240         {
 241             /* OK, we're up! */
 242             uint16_t r = f->radiusnew(f->get_id_by_session(s));
 243             if (r) f->radiussend(r, RADIUSSTART);
 244         }
 245     }
 246
 247     return 1;
 248 }
 249
 250 int plugin_init(struct pluginfuncs *funcs)
 251 {
 252     FILE *tables;
 253     int found_nat = 0;
 254
 255     if (!funcs)
 256         return 0;
 257
 258     f = funcs;
 259
 260     if ((tables = fopen("/proc/net/ip_tables_names", "r")))
 261     {
 262         char buf[1024];
 263         while (fgets(buf, sizeof(buf), tables) && !found_nat)
 264             found_nat = !strcmp(buf, "nat\n");
 265
 266         fclose(tables);
 267     }
 268
 269     /* master killed/crashed? */
 270     if (found_nat)
 271     {
 272         int i;
 273         for (i = 0; down_commands[i] && *down_commands[i]; i++)
 274         {
 275             f->log(3, 0, 0, "Running %s\n", down_commands[i]);
 276             system(down_commands[i]);
 277         }
 278     }
 279
 280     return 1;
 281 }
 282
 283 void plugin_done()
 284 {
 285     int i;
 286
 287     if (!iam_master)    // Never became master. nothing to do.
 288         return;
 289
 290     for (i = 0; down_commands[i] && *down_commands[i]; i++)
 291     {
 292         f->log(3, 0, 0, "Running %s\n", down_commands[i]);
 293         system(down_commands[i]);
 294     }
 295 }
 296