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 <netinet/ip6.h>
   7 #include "dhcp6.h"
   8 #include "l2tpns.h"
   9 #include "plugin.h"
  10 #include "control.h"
  11
  12 /* walled garden */
  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.netfilter.ip_conntrack_max=512000"      // lots of entries
  27              " net.ipv4.netfilter.ip_conntrack_tcp_timeout_established=18000 >/dev/null", // 5hrs
  28     NULL,
  29 };
  30
  31 char *down_commands[] = {
  32     "iptables -t nat -F PREROUTING",
  33     "iptables -t nat -F garden_users",
  34     "iptables -t nat -X garden_users",
  35     "iptables -t nat -F garden",
  36     "iptables -t nat -X garden",
  37     "rmmod iptable_nat",        // Should also remove ip_conntrack, but
  38                                 // doing so can take hours...  literally.
  39                                 // If a master is re-started as a slave,
  40                                 // either rmmod manually, or reboot.
  41     NULL,
  42 };
  43
  44 #define F_UNGARDEN      0
  45 #define F_GARDEN        1
  46 #define F_CLEANUP       2
  47
  48 int garden_session(sessiont *s, int flag, char *newuser);
  49
  50 int plugin_post_auth(struct param_post_auth *data)
  51 {
  52     // Ignore if user authentication was successful
  53     if (data->auth_allowed)
  54         return PLUGIN_RET_OK;
  55
  56     f->log(3, f->get_id_by_session(data->s), data->s->tunnel,
  57         "Walled Garden allowing login\n");
  58
  59     data->auth_allowed = 1;
  60     data->s->walled_garden = 1;
  61     return PLUGIN_RET_OK;
  62 }
  63
  64 int plugin_new_session(struct param_new_session *data)
  65 {
  66     if (!iam_master)
  67         return PLUGIN_RET_OK;   // Slaves don't do walled garden processing.
  68
  69     if (data->s->walled_garden)
  70         garden_session(data->s, F_GARDEN, 0);
  71
  72     return PLUGIN_RET_OK;
  73 }
  74
  75 int plugin_kill_session(struct param_new_session *data)
  76 {
  77     if (!iam_master)
  78         return PLUGIN_RET_OK;   // Slaves don't do walled garden processing.
  79
  80     if (data->s->walled_garden)
  81         garden_session(data->s, F_CLEANUP, 0);
  82
  83     return PLUGIN_RET_OK;
  84 }
  85
  86 char *plugin_control_help[] = {
  87     "  garden USER|SID                             Put user into the walled garden",
  88     "  ungarden SID [USER]                         Release session from garden",
  89     0
  90 };
  91
  92 int plugin_control(struct param_control *data)
  93 {
  94     sessionidt session;
  95     sessiont *s = 0;
  96     int flag;
  97     char *end;
  98
  99     if (data->argc < 1)
 100         return PLUGIN_RET_OK;
 101
 102     if (strcmp(data->argv[0], "garden") && strcmp(data->argv[0], "ungarden"))
 103         return PLUGIN_RET_OK; // not for us
 104
 105     if (!iam_master)
 106         return PLUGIN_RET_NOTMASTER;
 107
 108     flag = data->argv[0][0] == 'g' ? F_GARDEN : F_UNGARDEN;
 109
 110     if (data->argc < 2 || data->argc > 3 || (data->argc > 2 && flag == F_GARDEN))
 111     {
 112         data->response = NSCTL_RES_ERR;
 113         data->additional = flag == F_GARDEN
 114             ? "requires username or session id"
 115             : "requires session id and optional username";
 116
 117         return PLUGIN_RET_STOP;
 118     }
 119
 120     if (!(session = strtol(data->argv[1], &end, 10)) || *end)
 121     {
 122         if (flag)
 123             session = f->get_session_by_username(data->argv[1]);
 124         else
 125             session = 0; // can't ungarden by username
 126     }
 127
 128     if (session)
 129         s = f->get_session_by_id(session);
 130
 131     if (!s || !s->ip)
 132     {
 133         data->response = NSCTL_RES_ERR;
 134         data->additional = "session not found";
 135         return PLUGIN_RET_STOP;
 136     }
 137
 138     if (s->walled_garden == flag)
 139     {
 140         data->response = NSCTL_RES_ERR;
 141         data->additional = flag ? "already in walled garden" : "not in walled garden";
 142         return PLUGIN_RET_STOP;
 143     }
 144
 145     garden_session(s, flag, data->argc > 2 ? data->argv[2] : 0);
 146     f->session_changed(session);
 147
 148     data->response = NSCTL_RES_OK;
 149     data->additional = 0;
 150
 151     return PLUGIN_RET_STOP;
 152 }
 153
 154 int plugin_become_master(void)
 155 {
 156     int i;
 157     iam_master = 1;     // We just became the master. Wow!
 158
 159     for (i = 0; up_commands[i] && *up_commands[i]; i++)
 160     {
 161         f->log(3, 0, 0, "Running %s\n", up_commands[i]);
 162         if (-1 == system(up_commands[i])) f->log(0, 0, 0, "error command %s\n", up_commands[i]);
 163     }
 164
 165     return PLUGIN_RET_OK;
 166 }
 167
 168 // Called for each active session after becoming master
 169 int plugin_new_session_master(sessiont *s)
 170 {
 171     if (s->walled_garden)
 172         garden_session(s, F_GARDEN, 0);
 173
 174     return PLUGIN_RET_OK;
 175 }
 176
 177 int garden_session(sessiont *s, int flag, char *newuser)
 178 {
 179     char cmd[2048];
 180     sessionidt sess;
 181         int status;
 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         status = 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             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             if (-1 == system(down_commands[i])) f->log(0, 0, 0, "error command %s\n", 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         if (-1 == system(down_commands[i])) f->log(0, 0, 0, "error command %s\n", down_commands[i]);
 296     }
 297 }
 298