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 <sys/socket.h>
   7 #include <linux/rtnetlink.h>
   8
   9 #include "l2tpns.h"
  10 #include "plugin.h"
  11 #include "control.h"
  12
  13 /* walled garden */
  14
  15 int plugin_api_version = PLUGIN_API_VERSION;
  16 static struct pluginfuncs *f = 0;
  17
  18 static int iam_master = 0;      // We're all slaves! Slaves I tell you!
  19
  20 char *up_commands[] = {
  21     "iptables -t nat -N garden >/dev/null 2>&1",                // Create a chain that all gardened users will go through
  22     "iptables -t nat -F garden",
  23     ". " PLUGINCONF "/build-garden",                            // Populate with site-specific DNAT rules
  24     "iptables -t nat -N garden_users >/dev/null 2>&1",          // Empty chain, users added/removed by garden_session
  25     "iptables -t nat -F garden_users",
  26     "iptables -t nat -A PREROUTING -j garden_users",            // DNAT any users on the garden_users chain
  27     "sysctl -w net.ipv4.netfilter.ip_conntrack_max=512000"      // lots of entries
  28              " net.ipv4.netfilter.ip_conntrack_tcp_timeout_established=18000 >/dev/null", // 5hrs
  29     NULL,
  30 };
  31
  32 char *down_commands[] = {
  33     "iptables -t nat -F PREROUTING",
  34     "iptables -t nat -F garden_users",
  35     "iptables -t nat -X garden_users",
  36     "iptables -t nat -F garden",
  37     "iptables -t nat -X garden",
  38     "rmmod iptable_nat",        // Should also remove ip_conntrack, but
  39                                 // doing so can take hours...  literally.
  40                                 // If a master is re-started as a slave,
  41                                 // either rmmod manually, or reboot.
  42     NULL,
  43 };
  44
  45 #define F_UNGARDEN      0
  46 #define F_GARDEN        1
  47 #define F_CLEANUP       2
  48
  49 int garden_session(sessiont *s, int flag, char *newuser);
  50
  51 int plugin_post_auth(struct param_post_auth *data)
  52 {
  53     // Ignore if user authentication was successful
  54     if (data->auth_allowed)
  55         return PLUGIN_RET_OK;
  56
  57     f->log(3, f->get_id_by_session(data->s), data->s->tunnel,
  58         "Walled Garden allowing login\n");
  59
  60     data->auth_allowed = 1;
  61     data->s->walled_garden = 1;
  62     return PLUGIN_RET_OK;
  63 }
  64
  65 int plugin_new_session(struct param_new_session *data)
  66 {
  67     if (!iam_master)
  68         return PLUGIN_RET_OK;   // Slaves don't do walled garden processing.
  69
  70     if (data->s->walled_garden)
  71         garden_session(data->s, F_GARDEN, 0);
  72
  73     return PLUGIN_RET_OK;
  74 }
  75
  76 int plugin_kill_session(struct param_new_session *data)
  77 {
  78     if (!iam_master)
  79         return PLUGIN_RET_OK;   // Slaves don't do walled garden processing.
  80
  81     if (data->s->walled_garden)
  82         garden_session(data->s, F_CLEANUP, 0);
  83
  84     return PLUGIN_RET_OK;
  85 }
  86
  87 char *plugin_control_help[] = {
  88     "  garden USER|SID                             Put user into the walled garden",
  89     "  ungarden SID [USER]                         Release session from garden",
  90     0
  91 };
  92
  93 int plugin_control(struct param_control *data)
  94 {
  95     sessionidt session;
  96     sessiont *s = 0;
  97     int flag;
  98     char *end;
  99
 100     if (data->argc < 1)
 101         return PLUGIN_RET_OK;
 102
 103     if (strcmp(data->argv[0], "garden") && strcmp(data->argv[0], "ungarden"))
 104         return PLUGIN_RET_OK; // not for us
 105
 106     if (!iam_master)
 107         return PLUGIN_RET_NOTMASTER;
 108
 109     flag = data->argv[0][0] == 'g' ? F_GARDEN : F_UNGARDEN;
 110
 111     if (data->argc < 2 || data->argc > 3 || (data->argc > 2 && flag == F_GARDEN))
 112     {
 113         data->response = NSCTL_RES_ERR;
 114         data->additional = flag == F_GARDEN
 115             ? "requires username or session id"
 116             : "requires session id and optional username";
 117
 118         return PLUGIN_RET_STOP;
 119     }
 120
 121     if (!(session = strtol(data->argv[1], &end, 10)) || *end)
 122     {
 123         if (flag)
 124             session = f->get_session_by_username(data->argv[1]);
 125         else
 126             session = 0; // can't ungarden by username
 127     }
 128
 129     if (session)
 130         s = f->get_session_by_id(session);
 131
 132     if (!s || !s->ip)
 133     {
 134         data->response = NSCTL_RES_ERR;
 135         data->additional = "session not found";
 136         return PLUGIN_RET_STOP;
 137     }
 138
 139     if (s->walled_garden == flag)
 140     {
 141         data->response = NSCTL_RES_ERR;
 142         data->additional = flag ? "already in walled garden" : "not in walled garden";
 143         return PLUGIN_RET_STOP;
 144     }
 145
 146     garden_session(s, flag, data->argc > 2 ? data->argv[2] : 0);
 147     f->session_changed(session);
 148
 149     data->response = NSCTL_RES_OK;
 150     data->additional = 0;
 151
 152     return PLUGIN_RET_STOP;
 153 }
 154
 155 int plugin_become_master(void)
 156 {
 157     int i;
 158     iam_master = 1;     // We just became the master. Wow!
 159
 160     for (i = 0; up_commands[i] && *up_commands[i]; i++)
 161     {
 162         f->log(3, 0, 0, "Running %s\n", up_commands[i]);
 163         system(up_commands[i]);
 164     }
 165
 166     return PLUGIN_RET_OK;
 167 }
 168
 169 // Called for each active session after becoming master
 170 int plugin_new_session_master(sessiont *s)
 171 {
 172     if (s->walled_garden)
 173         garden_session(s, F_GARDEN, 0);
 174
 175     return PLUGIN_RET_OK;
 176 }
 177
 178 int garden_session(sessiont *s, int flag, char *newuser)
 179 {
 180     char cmd[2048];
 181     sessionidt sess;
 182
 183     if (!s) return 0;
 184     if (!s->opened) return 0;
 185
 186     sess = f->get_id_by_session(s);
 187     if (flag == F_GARDEN)
 188     {
 189         f->log(2, sess, s->tunnel, "Garden user %s (%s)\n", s->user,
 190             f->fmtaddr(htonl(s->ip), 0));
 191
 192         snprintf(cmd, sizeof(cmd),
 193             "iptables -t nat -A garden_users -s %s -j garden",
 194             f->fmtaddr(htonl(s->ip), 0));
 195
 196         f->log(3, sess, s->tunnel, "%s\n", cmd);
 197         system(cmd);
 198         s->walled_garden = 1;
 199     }
 200     else
 201     {
 202         sessionidt other;
 203         int count = 40;
 204
 205         // Normal User
 206         f->log(2, sess, s->tunnel, "Un-Garden user %s (%s)\n", s->user, f->fmtaddr(htonl(s->ip), 0));
 207         if (newuser)
 208         {
 209             snprintf(s->user, MAXUSER, "%s", newuser);
 210             f->log(2, sess, s->tunnel, "  Setting username to %s\n", s->user);
 211         }
 212
 213         // Kick off any duplicate usernames
 214         // but make sure not to kick off ourself
 215         if (s->ip && !s->die && (other = f->get_session_by_username(s->user)) &&
 216             s != f->get_session_by_id(other))
 217         {
 218             f->sessionkill(other,
 219                 "Duplicate session when user released from walled garden");
 220         }
 221
 222         /* Clean up counters */
 223         s->pin = s->pout = 0;
 224         s->cin = s->cout = 0;
 225         s->cin_delta = s->cout_delta = 0;
 226         s->cin_wrap = s->cout_wrap = 0;
 227
 228         snprintf(cmd, sizeof(cmd),
 229             "iptables -t nat -D garden_users -s %s -j garden",
 230             f->fmtaddr(htonl(s->ip), 0));
 231
 232         f->log(3, sess, s->tunnel, "%s\n", cmd);
 233         while (--count)
 234         {
 235             int status = system(cmd);
 236             if (WEXITSTATUS(status) != 0) break;
 237         }
 238
 239         s->walled_garden = 0;
 240
 241         if (flag != F_CLEANUP)
 242         {
 243             /* OK, we're up! */
 244             uint16_t r = f->radiusnew(f->get_id_by_session(s));
 245             if (r) f->radiussend(r, RADIUSSTART);
 246         }
 247     }
 248
 249     return 1;
 250 }
 251
 252 int plugin_init(struct pluginfuncs *funcs)
 253 {
 254     FILE *tables;
 255     int found_nat = 0;
 256
 257     if (!funcs)
 258         return 0;
 259
 260     f = funcs;
 261
 262     if ((tables = fopen("/proc/net/ip_tables_names", "r")))
 263     {
 264         char buf[1024];
 265         while (fgets(buf, sizeof(buf), tables) && !found_nat)
 266             found_nat = !strcmp(buf, "nat\n");
 267
 268         fclose(tables);
 269     }
 270
 271     /* master killed/crashed? */
 272     if (found_nat)
 273     {
 274         int i;
 275         for (i = 0; down_commands[i] && *down_commands[i]; i++)
 276         {
 277             f->log(3, 0, 0, "Running %s\n", down_commands[i]);
 278             system(down_commands[i]);
 279         }
 280     }
 281
 282     return 1;
 283 }
 284
 285 void plugin_done()
 286 {
 287     int i;
 288
 289     if (!iam_master)    // Never became master. nothing to do.
 290         return;
 291
 292     for (i = 0; down_commands[i] && *down_commands[i]; i++)
 293     {
 294         f->log(3, 0, 0, "Running %s\n", down_commands[i]);
 295         system(down_commands[i]);
 296     }
 297 }
 298