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Sourcecode: l2tpns version File versions  Download package

garden.c

#include <string.h>
#include <malloc.h>
#include <stdlib.h>
#include <sys/wait.h>
#include <sys/types.h>
#include "l2tpns.h"
#include "plugin.h"
#include "control.h"

/* walled garden */

char const *cvs_id = "$Id: garden.c,v 1.24 2005/10/11 09:04:53 bodea Exp $";

int plugin_api_version = PLUGIN_API_VERSION;
static struct pluginfuncs *f = 0;

static int iam_master = 0;    // We're all slaves! Slaves I tell you!

char *up_commands[] = {
    "iptables -t nat -N garden >/dev/null 2>&1",            // Create a chain that all gardened users will go through
    "iptables -t nat -F garden",
    ". " PLUGINCONF "/build-garden",                        // Populate with site-specific DNAT rules
    "iptables -t nat -N garden_users >/dev/null 2>&1",            // Empty chain, users added/removed by garden_session
    "iptables -t nat -F garden_users",
    "iptables -t nat -A PREROUTING -j garden_users",        // DNAT any users on the garden_users chain
    "sysctl -w net.ipv4.ip_conntrack_max=512000 >/dev/null",      // lots of entries
    NULL,
};

char *down_commands[] = {
    "iptables -t nat -F PREROUTING",
    "iptables -t nat -F garden_users",
    "iptables -t nat -X garden_users",
    "iptables -t nat -F garden",
    "iptables -t nat -X garden",
    "rmmod iptable_nat",      // Should also remove ip_conntrack, but
                        // doing so can take hours...  literally.
                        // If a master is re-started as a slave,
                        // either rmmod manually, or reboot.
    NULL,
};

#define F_UNGARDEN      0
#define F_GARDEN  1
#define F_CLEANUP 2

int garden_session(sessiont *s, int flag, char *newuser);

int plugin_post_auth(struct param_post_auth *data)
{
    // Ignore if user authentication was successful
    if (data->auth_allowed)
      return PLUGIN_RET_OK;

    f->log(3, f->get_id_by_session(data->s), data->s->tunnel,
      "Walled Garden allowing login\n");

    data->auth_allowed = 1;
    data->s->walled_garden = 1;
    return PLUGIN_RET_OK;
}

int plugin_new_session(struct param_new_session *data)
{
    if (!iam_master)
      return PLUGIN_RET_OK;   // Slaves don't do walled garden processing.

    if (data->s->walled_garden)
      garden_session(data->s, F_GARDEN, 0);

    return PLUGIN_RET_OK;
}

int plugin_kill_session(struct param_new_session *data)
{
    if (!iam_master)
      return PLUGIN_RET_OK;   // Slaves don't do walled garden processing.

    if (data->s->walled_garden)
      garden_session(data->s, F_CLEANUP, 0);

    return PLUGIN_RET_OK;
}

char *plugin_control_help[] = {
    "  garden USER|SID                             Put user into the walled garden",
    "  ungarden SID [USER]                         Release session from garden",
    0
};

int plugin_control(struct param_control *data)
{
    sessionidt session;
    sessiont *s = 0;
    int flag;
    char *end;

    if (data->argc < 1)
      return PLUGIN_RET_OK;

    if (strcmp(data->argv[0], "garden") && strcmp(data->argv[0], "ungarden"))
      return PLUGIN_RET_OK; // not for us

    if (!iam_master)
      return PLUGIN_RET_NOTMASTER;

    flag = data->argv[0][0] == 'g' ? F_GARDEN : F_UNGARDEN;

    if (data->argc < 2 || data->argc > 3 || (data->argc > 2 && flag == F_GARDEN))
    {
      data->response = NSCTL_RES_ERR;
      data->additional = flag == F_GARDEN
          ? "requires username or session id"
          : "requires session id and optional username";

      return PLUGIN_RET_STOP;
    }

    if (!(session = strtol(data->argv[1], &end, 10)) || *end)
    {
      if (flag)
          session = f->get_session_by_username(data->argv[1]);
      else
          session = 0; // can't ungarden by username
    }

    if (session)
      s = f->get_session_by_id(session);

    if (!s || !s->ip)
    {
      data->response = NSCTL_RES_ERR;
      data->additional = "session not found";
      return PLUGIN_RET_STOP;
    }

    if (s->walled_garden == flag)
    {
      data->response = NSCTL_RES_ERR;
      data->additional = flag ? "already in walled garden" : "not in walled garden";
      return PLUGIN_RET_STOP;
    }

    garden_session(s, flag, data->argc > 2 ? data->argv[2] : 0);
    f->session_changed(session);

    data->response = NSCTL_RES_OK;
    data->additional = 0;

    return PLUGIN_RET_STOP;
}

int plugin_become_master(void)
{
    int i;
    iam_master = 1;     // We just became the master. Wow!

    for (i = 0; up_commands[i] && *up_commands[i]; i++)
    {
      f->log(3, 0, 0, "Running %s\n", up_commands[i]);
      system(up_commands[i]);
    }

    return PLUGIN_RET_OK;
}

// Called for each active session after becoming master
int plugin_new_session_master(sessiont *s)
{     
    if (s->walled_garden)
      garden_session(s, F_GARDEN, 0);

    return PLUGIN_RET_OK;
}

int garden_session(sessiont *s, int flag, char *newuser)
{
    char cmd[2048];
    sessionidt sess;

    if (!s) return 0;
    if (!s->opened) return 0;

    sess = f->get_id_by_session(s);
    if (flag == F_GARDEN)
    {
      f->log(2, sess, s->tunnel, "Garden user %s (%s)\n", s->user,
          f->fmtaddr(htonl(s->ip), 0));

      snprintf(cmd, sizeof(cmd),
          "iptables -t nat -A garden_users -s %s -j garden",
          f->fmtaddr(htonl(s->ip), 0));

      f->log(3, sess, s->tunnel, "%s\n", cmd);
      system(cmd);
      s->walled_garden = 1;
    }
    else
    {
      sessionidt other;
      int count = 40;

      // Normal User
      f->log(2, sess, s->tunnel, "Un-Garden user %s (%s)\n", s->user, f->fmtaddr(htonl(s->ip), 0));
      if (newuser)
      {
          snprintf(s->user, MAXUSER, "%s", newuser);
          f->log(2, sess, s->tunnel, "  Setting username to %s\n", s->user);
      }

      // Kick off any duplicate usernames
      // but make sure not to kick off ourself
      if (s->ip && !s->die && (other = f->get_session_by_username(s->user)) &&
          s != f->get_session_by_id(other))
      {
          f->sessionkill(other,
            "Duplicate session when user released from walled garden");
      }

      /* Clean up counters */
      s->pin = s->pout = 0;
      s->cin = s->cout = 0;
      s->cin_delta = s->cout_delta = 0;
      s->cin_wrap = s->cout_wrap = 0;

      snprintf(cmd, sizeof(cmd),
          "iptables -t nat -D garden_users -s %s -j garden",
          f->fmtaddr(htonl(s->ip), 0));

      f->log(3, sess, s->tunnel, "%s\n", cmd);
      while (--count)
      {
          int status = system(cmd);
          if (WEXITSTATUS(status) != 0) break;
      }

      s->walled_garden = 0;

      if (flag != F_CLEANUP)
      {
          /* OK, we're up! */
          uint16_t r = f->radiusnew(f->get_id_by_session(s));
          if (r) f->radiussend(r, RADIUSSTART);
      }
    }

    return 1;
}

int plugin_init(struct pluginfuncs *funcs)
{
    FILE *tables;
    int found_nat = 0;

    if (!funcs)
      return 0;

    f = funcs;

    if ((tables = fopen("/proc/net/ip_tables_names", "r")))
    {
      char buf[1024];
      while (fgets(buf, sizeof(buf), tables) && !found_nat)
          found_nat = !strcmp(buf, "nat\n");

      fclose(tables);
    }

    /* master killed/crashed? */
    if (found_nat)
    {
      int i;
      for (i = 0; down_commands[i] && *down_commands[i]; i++)
      {
          f->log(3, 0, 0, "Running %s\n", down_commands[i]);
          system(down_commands[i]);
      }
    }

    return 1;
}

void plugin_done()
{
    int i;

    if (!iam_master)    // Never became master. nothing to do.
      return;

    for (i = 0; down_commands[i] && *down_commands[i]; i++)
    {
      f->log(3, 0, 0, "Running %s\n", down_commands[i]);
      system(down_commands[i]);
    }
}


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