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 1.20 2004/12/16 08:49:53 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=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);
  48
  49 int plugin_post_auth(struct param_post_auth *data)
  50 {
  51         // Ignore if user authentication was successful
  52         if (data->auth_allowed) return PLUGIN_RET_OK;
  53
  54         p->log(3, p->get_id_by_session(data->s), data->s->tunnel, "Walled Garden allowing login\n");
  55         data->auth_allowed = 1;
  56         data->s->walled_garden = 1;
  57         return PLUGIN_RET_OK;
  58 }
  59
  60 int plugin_new_session(struct param_new_session *data)
  61 {
  62         if (!iam_master)
  63                 return PLUGIN_RET_OK;   // Slaves don't do walled garden processing.
  64
  65         if (data->s->walled_garden)
  66                 garden_session(data->s, F_GARDEN);
  67
  68         return PLUGIN_RET_OK;
  69 }
  70
  71 int plugin_kill_session(struct param_new_session *data)
  72 {
  73         if (!iam_master)
  74                 return PLUGIN_RET_OK;   // Slaves don't do walled garden processing.
  75
  76         if (data->s->walled_garden)
  77                 garden_session(data->s, F_CLEANUP);
  78
  79         return PLUGIN_RET_OK;
  80 }
  81
  82 char *plugin_control_help[] = {
  83         "  garden USER|SID                             Put user into the walled garden",
  84         "  ungarden SID                                Release session from garden",
  85         0
  86 };
  87
  88 int plugin_control(struct param_control *data)
  89 {
  90         sessionidt session;
  91         sessiont *s = 0;
  92         int flag;
  93         char *end;
  94
  95         if (data->argc < 1)
  96                 return PLUGIN_RET_OK;
  97
  98         if (strcmp(data->argv[0], "garden") && strcmp(data->argv[0], "ungarden"))
  99                 return PLUGIN_RET_OK; // not for us
 100
 101         if (!iam_master)
 102                 return PLUGIN_RET_NOTMASTER;
 103
 104         flag = data->argv[0][0] == 'g' ? F_GARDEN : F_UNGARDEN;
 105
 106         if (data->argc != 2)
 107         {
 108                 data->response = NSCTL_RES_ERR;
 109                 data->additional = "one argument required: username or session id";
 110                 return PLUGIN_RET_STOP;
 111         }
 112
 113         if (!(session = strtol(data->argv[1], &end, 10)) || *end)
 114         {
 115                 if (flag)
 116                         session = p->get_session_by_username(data->argv[1]);
 117                 else
 118                         session = 0; // can't ungarden by username
 119         }
 120
 121         if (session)
 122                 s = p->get_session_by_id(session);
 123
 124         if (!s || !s->ip)
 125         {
 126                 data->response = NSCTL_RES_ERR;
 127                 data->additional = "session not found";
 128                 return PLUGIN_RET_STOP;
 129         }
 130
 131         if (s->walled_garden == flag)
 132         {
 133                 data->response = NSCTL_RES_ERR;
 134                 data->additional = flag ? "already in walled garden" : "not in walled garden";
 135                 return PLUGIN_RET_STOP;
 136         }
 137
 138         garden_session(s, flag);
 139         p->session_changed(session);
 140
 141         data->response = NSCTL_RES_OK;
 142         data->additional = 0;
 143
 144         return PLUGIN_RET_STOP;
 145 }
 146
 147 int plugin_become_master(void)
 148 {
 149         int i;
 150         iam_master = 1; // We just became the master. Wow!
 151
 152         for (i = 0; up_commands[i] && *up_commands[i]; i++)
 153         {
 154                 p->log(3, 0, 0, "Running %s\n", up_commands[i]);
 155                 system(up_commands[i]);
 156         }
 157
 158         return PLUGIN_RET_OK;
 159 }
 160
 161 // Called for each active session after becoming master
 162 int plugin_new_session_master(sessiont *s)
 163 {
 164         if (s->walled_garden)
 165                 garden_session(s, F_GARDEN);
 166
 167         return PLUGIN_RET_OK;
 168 }
 169
 170 int garden_session(sessiont *s, int flag)
 171 {
 172         char cmd[2048];
 173         sessionidt sess;
 174
 175         if (!s) return 0;
 176         if (!s->opened) return 0;
 177
 178         sess = p->get_id_by_session(s);
 179         if (flag == F_GARDEN)
 180         {
 181                 p->log(2, sess, s->tunnel, "Garden user %s (%s)\n", s->user, p->fmtaddr(htonl(s->ip), 0));
 182                 snprintf(cmd, sizeof(cmd), "iptables -t nat -A garden_users -s %s -j garden", p->fmtaddr(htonl(s->ip), 0));
 183                 p->log(3, sess, s->tunnel, "%s\n", cmd);
 184                 system(cmd);
 185                 s->walled_garden = 1;
 186         }
 187         else
 188         {
 189                 sessionidt other;
 190                 int count = 40;
 191
 192                 // Normal User
 193                 p->log(2, sess, s->tunnel, "Un-Garden user %s (%s)\n", s->user, p->fmtaddr(htonl(s->ip), 0));
 194                 // Kick off any duplicate usernames
 195                 // but make sure not to kick off ourself
 196                 if (s->ip && !s->die && (other = p->get_session_by_username(s->user)) && s != p->get_session_by_id(other)) {
 197                         p->sessionkill(other, "Duplicate session when user released from walled garden");
 198                 }
 199                 /* Clean up counters */
 200                 s->cin = s->cout = 0;
 201                 s->pin = s->pout = 0;
 202
 203                 snprintf(cmd, sizeof(cmd), "iptables -t nat -D garden_users -s %s -j garden", p->fmtaddr(htonl(s->ip), 0));
 204                 p->log(3, sess, s->tunnel, "%s\n", cmd);
 205                 while (--count)
 206                 {
 207                         int status = system(cmd);
 208                         if (WEXITSTATUS(status) != 0) break;
 209                 }
 210
 211                 s->walled_garden = 0;
 212
 213                 if (flag != F_CLEANUP)
 214                 {
 215                         /* OK, we're up! */
 216                         uint16_t r = p->radiusnew(p->get_id_by_session(s));
 217                         p->radiussend(r, RADIUSSTART);
 218                 }
 219         }
 220
 221         return 1;
 222 }
 223
 224 int plugin_init(struct pluginfuncs *funcs)
 225 {
 226         FILE *tables;
 227         int found_nat = 0;
 228
 229         if (!funcs)
 230                 return 0;
 231
 232         p = funcs;
 233
 234         if ((tables = fopen("/proc/net/ip_tables_names", "r")))
 235         {
 236                 char buf[1024];
 237                 while (fgets(buf, sizeof(buf), tables) && !found_nat)
 238                         found_nat = !strcmp(buf, "nat\n");
 239
 240                 fclose(tables);
 241         }
 242
 243         /* master killed/crashed? */
 244         if (found_nat)
 245         {
 246                 int i;
 247                 for (i = 0; down_commands[i] && *down_commands[i]; i++)
 248                 {
 249                         p->log(3, 0, 0, "Running %s\n", down_commands[i]);
 250                         system(down_commands[i]);
 251                 }
 252         }
 253
 254         return 1;
 255 }
 256
 257 void plugin_done()
 258 {
 259         int i;
 260
 261         if (!iam_master)        // Never became master. nothing to do.
 262                 return;
 263
 264         for (i = 0; down_commands[i] && *down_commands[i]; i++)
 265         {
 266                 p->log(3, 0, 0, "Running %s\n", down_commands[i]);
 267                 system(down_commands[i]);
 268         }
 269 }
 270