tor/src/tools/tor-fw-helper/tor-fw-helper-natpmp.c

/* Copyright (c) 2010, Jacob Appelbaum, Steven J. Murdoch.
 * Copyright (c) 2010, The Tor Project, Inc. */
/* See LICENSE for licensing information */

/**
  * \file tor-fw-helper-natpmp.c
  * \brief The implementation of our NAT-PMP firewall helper.
  **/

#include "orconfig.h"
#ifdef NAT_PMP
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <arpa/inet.h>

// debugging stuff
#include <assert.h>

#include "tor-fw-helper.h"
#include "tor-fw-helper-natpmp.h"

/** This hooks NAT-PMP into our multi-backend API. */
static tor_fw_backend_t tor_natpmp_backend = {
    "natpmp",
    sizeof(struct natpmp_state_t),
    tor_natpmp_init,
    tor_natpmp_cleanup,
    tor_natpmp_fetch_public_ip,
    tor_natpmp_add_tcp_mapping
};

/** Return the backend for NAT-PMP. */
const tor_fw_backend_t *
tor_fw_get_natpmp_backend(void)
{
    return &tor_natpmp_backend;
}

/** Initialize the NAT-PMP backend and store the results in
 * <b>backend_state</b>.*/
int
tor_natpmp_init(tor_fw_options_t *tor_fw_options, void *backend_state)
{
    natpmp_state_t *state = (natpmp_state_t *) backend_state;
    int r = 0;

    memset(&(state->natpmp), 0, sizeof(natpmp_t));
    memset(&(state->response), 0, sizeof(natpmpresp_t));
    state->init = 0;
    state->protocol = NATPMP_PROTOCOL_TCP;
    state->lease = NATPMP_DEFAULT_LEASE;

    if (tor_fw_options->verbose)
        fprintf(stdout, "V: natpmp init...\n");

    r = initnatpmp(&(state->natpmp));
    if (r == 0) {
        state->init = 1;
        fprintf(stdout, "tor-fw-helper: natpmp initialized...\n");
        return r;
    } else {
        fprintf(stderr, "tor-fw-helper: natpmp failed to initialize...\n");
        return r;
    }
}

/** Tear down the NAT-PMP connection stored in <b>backend_state</b>.*/
int
tor_natpmp_cleanup(tor_fw_options_t *tor_fw_options, void *backend_state)
{
    natpmp_state_t *state = (natpmp_state_t *) backend_state;
    int r = 0;
    if (tor_fw_options->verbose)
        fprintf(stdout, "V: natpmp cleanup...\n");
    r = closenatpmp(&(state->natpmp));
    if (tor_fw_options->verbose)
        fprintf(stdout, "V: closing natpmp socket: %d\n", r);
    return r;
}

/** Add a TCP port mapping for a single port stored in <b>tor_fw_options</b>
 * using the <b>natpmp_t</b> stored in <b>backend_state</b>. */
int
tor_natpmp_add_tcp_mapping(tor_fw_options_t *tor_fw_options,
                           void *backend_state)
{
    natpmp_state_t *state = (natpmp_state_t *) backend_state;
    int r = 0;
    int x = 0;
    int sav_errno;

    fd_set fds;
    struct timeval timeout;

    if (tor_fw_options->verbose)
        fprintf(stdout, "V: sending natpmp portmapping request...\n");
    r = sendnewportmappingrequest(&(state->natpmp), state->protocol,
                                  tor_fw_options->internal_port,
                                  tor_fw_options->external_port,
                                  state->lease);
    if (tor_fw_options->verbose)
        fprintf(stdout, "tor-fw-helper: NAT-PMP sendnewportmappingrequest "
                "returned %d (%s)\n", r, r==12?"SUCCESS":"FAILED");

    do {
        FD_ZERO(&fds);
        FD_SET(state->natpmp.s, &fds);
        getnatpmprequesttimeout(&(state->natpmp), &timeout);
        x = select(FD_SETSIZE, &fds, NULL, NULL, &timeout);
        if (x == -1)
        {
            fprintf(stdout, "V: select failed in "
                    "tor_natpmp_fetch_public_ip.\n");
            return -1;
        }

        if (tor_fw_options->verbose)
            fprintf(stdout, "V: attempting to readnatpmpreponseorretry...\n");
        r = readnatpmpresponseorretry(&(state->natpmp), &(state->response));
        sav_errno = errno;

        if (r<0 && r!=NATPMP_TRYAGAIN)
        {
            fprintf(stderr, "E: readnatpmpresponseorretry failed %d\n", r);
            fprintf(stderr, "E: errno=%d '%s'\n", sav_errno,
                    strerror(sav_errno));
        }

    } while ( r == NATPMP_TRYAGAIN );

    if (r != 0)
    {
        /* XXX TODO: NATPMP_* should be formatted into useful error strings */
        fprintf(stderr, "E: NAT-PMP It appears that something went wrong:"
                " %d\n", r);
        if (r == -51)
            fprintf(stderr, "E: NAT-PMP It appears that the request was "
                    "unauthorized\n");
        return r;
    }

    if (r == NATPMP_SUCCESS) {
        fprintf(stdout, "tor-fw-helper: NAT-PMP mapped public port %hu to"
                " localport %hu liftime %u\n",
                (state->response).pnu.newportmapping.mappedpublicport,
                (state->response).pnu.newportmapping.privateport,
                (state->response).pnu.newportmapping.lifetime);
    }

    tor_fw_options->nat_pmp_status = 1;

    return r;
}

/** Fetch our likely public IP from our upstream NAT-PMP enabled NAT device.
 * Use the connection context stored in <b>backend_state</b>. */
int
tor_natpmp_fetch_public_ip(tor_fw_options_t *tor_fw_options,
                           void *backend_state)
{
    int r = 0;
    int x = 0;
    int sav_errno;
    natpmp_state_t *state = (natpmp_state_t *) backend_state;

    struct timeval timeout;
    fd_set fds;

    r = sendpublicaddressrequest(&(state->natpmp));
    fprintf(stdout, "tor-fw-helper: NAT-PMP sendpublicaddressrequest returned"
            " %d (%s)\n", r, r==2?"SUCCESS":"FAILED");

    do {

        if (state->natpmp.s >= FD_SETSIZE)
        {
            fprintf(stderr, "E: NAT-PMP FD_SETSIZE error %d\n",
                    state->natpmp.s);
            return -1;
        }
        FD_ZERO(&fds);
        FD_SET(state->natpmp.s, &fds);
        getnatpmprequesttimeout(&(state->natpmp), &timeout);
        x = select(FD_SETSIZE, &fds, NULL, NULL, &timeout);
        if (x == -1)
        {
            fprintf(stdout, "V: select failed in "
                    "tor_natpmp_fetch_public_ip.\n");
            return -1;
        }

        if (tor_fw_options->verbose)
            fprintf(stdout, "V: NAT-PMP attempting to read reponse...\n");
        r = readnatpmpresponseorretry(&(state->natpmp), &(state->response));
        sav_errno = errno;

        if (tor_fw_options->verbose)
            fprintf(stdout, "V: NAT-PMP readnatpmpresponseorretry returned"
                    " %d\n", r);

        if ( r < 0 && r != NATPMP_TRYAGAIN)
        {
            fprintf(stderr, "E: NAT-PMP readnatpmpresponseorretry failed %d\n",
                    r);
            fprintf(stderr, "E: NAT-PMP errno=%d '%s'\n", sav_errno,
                    strerror(sav_errno));
        }

    } while ( r == NATPMP_TRYAGAIN );

    if (r != 0)
    {
        fprintf(stderr, "E: NAT-PMP It appears that something went wrong:"
                " %d\n", r);
        return r;
    }

    fprintf(stdout, "tor-fw-helper: ExternalIPAddress = %s\n",
           inet_ntoa((state->response).pnu.publicaddress.addr));
    tor_fw_options->public_ip_status = 1;

    if (tor_fw_options->verbose)
    {
        fprintf(stdout, "V: result = %u\n", r);
        fprintf(stdout, "V: type = %u\n", (state->response).type);
        fprintf(stdout, "V: resultcode = %u\n", (state->response).resultcode);
        fprintf(stdout, "V: epoch = %u\n", (state->response).epoch);
    }

    return r;
}
#endif