gnunet-nat-server.c File Reference

#include "platform.h"
#include "gnunet_util_lib.h"
#include "gnunet_nat_service.h"
#include "gnunet_protocols.h"
#include "nat-auto.h"

Include dependency graph for gnunet-nat-server.c:

Go to the source code of this file.

Data Structures
struct	ClientData
	Information we track per client. More...
struct	TcpContext
	Closure for tcp_send. More...

Functions
static void	try_anat (uint32_t dst_ipv4, uint16_t dport, int is_tcp)
	Try contacting the peer using autonomous NAT traversal method. More...
static void	tcp_send (void *cls)
	Task called by the scheduler once we can do the TCP send (or once we failed to connect...). More...
static void	try_send_tcp (uint32_t dst_ipv4, uint16_t dport, uint16_t data)
	Try to send data to the IP dst_ipv4' at port dport via TCP. More...
static void	try_send_udp (uint32_t dst_ipv4, uint16_t dport, uint16_t data)
	Try to send data to the IP dst_ipv4 at port dport via UDP. More...
static void	handle_test (void *cls, const struct GNUNET_NAT_AUTO_TestMessage *tm)
	We've received a request to probe a NAT traversal. More...
static void	run (void *cls, const struct GNUNET_CONFIGURATION_Handle *c, struct GNUNET_SERVICE_Handle *srv)
	Main function that will be run. More...
static void	force_timeout (void *cls)
	Forcefully drops client after 1s. More...
static void *	client_connect_cb (void *cls, struct GNUNET_SERVICE_Client *c, struct GNUNET_MQ_Handle *mq)
	Callback called when a client connects to the service. More...
static void	client_disconnect_cb (void *cls, struct GNUNET_SERVICE_Client *c, void *internal_cls)
	Callback called when a client disconnected from the service. More...
	GNUNET_SERVICE_MAIN ("nat-server", GNUNET_SERVICE_OPTION_NONE, &run, &client_connect_cb, &client_disconnect_cb, NULL, GNUNET_MQ_hd_fixed_size(test, GNUNET_MESSAGE_TYPE_NAT_TEST, struct GNUNET_NAT_AUTO_TestMessage, NULL), GNUNET_MQ_handler_end())
	Define "main" method using service macro. More...

Variables
static const struct GNUNET_CONFIGURATION_Handle *	cfg
	Our configuration. More...

Function Documentation

try_anat()

static void try_anat ( uint32_t  dst_ipv4, uint16_t  dport, int  is_tcp  )

static

Try contacting the peer using autonomous NAT traversal method.

Parameters

dst_ipv4	IPv4 address to send the fake ICMP message
dport	destination port to include in ICMP message
is_tcp	mark for TCP (GNUNET_YES) or UDP (GNUNET_NO)

Definition at line 64 of file gnunet-nat-server.c.

{
  struct GNUNET_NAT_Handle *h;
  struct sockaddr_in lsa;
  struct sockaddr_in rsa;
  const struct sockaddr *sa;
  socklen_t sa_len;
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Asking for connection reversal with %x and code %u\n",
              (unsigned int) dst_ipv4,
              (unsigned int) dport);
  memset (&lsa, 0, sizeof(lsa));
  lsa.sin_family = AF_INET;
#if HAVE_SOCKADDR_IN_SIN_LEN
  lsa.sin_len = sizeof(sa);
#endif
  lsa.sin_addr.s_addr = 0;
  lsa.sin_port = htons (dport);
  memset (&rsa, 0, sizeof(rsa));
  rsa.sin_family = AF_INET;
#if HAVE_SOCKADDR_IN_SIN_LEN
  rsa.sin_len = sizeof(sa);
#endif
  rsa.sin_addr.s_addr = dst_ipv4;
  rsa.sin_port = htons (dport);
  sa_len = sizeof(lsa);
  sa = (const struct sockaddr *) &lsa;
  h = GNUNET_NAT_register (cfg,
                           "none",
                           is_tcp ? IPPROTO_TCP : IPPROTO_UDP,
                           1,
                           &sa,
                           &sa_len,
                           NULL, NULL, NULL);
  GNUNET_NAT_request_reversal (h,
                               &lsa,
                               &rsa);
  GNUNET_NAT_unregister (h);
}

References cfg, GNUNET_ERROR_TYPE_DEBUG, GNUNET_log, GNUNET_NAT_register(), GNUNET_NAT_request_reversal(), GNUNET_NAT_unregister(), and h.

Referenced by handle_test().

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tcp_send()

static void tcp_send ( void *  cls )

static

Task called by the scheduler once we can do the TCP send (or once we failed to connect...).

Parameters

cls	the struct TcpContext

Definition at line 132 of file gnunet-nat-server.c.

{
  struct TcpContext *ctx = cls;
  const struct GNUNET_SCHEDULER_TaskContext *tc;
 
  tc = GNUNET_SCHEDULER_get_task_context ();
  if ((NULL != tc->write_ready) &&
      (GNUNET_NETWORK_fdset_isset (tc->write_ready, ctx->s)))
  {
    if (-1 ==
        GNUNET_NETWORK_socket_send (ctx->s, &ctx->data, sizeof(ctx->data)))
    {
      GNUNET_log_strerror (GNUNET_ERROR_TYPE_DEBUG, "send");
    }
    GNUNET_NETWORK_socket_shutdown (ctx->s, SHUT_RDWR);
  }
  GNUNET_NETWORK_socket_close (ctx->s);
  GNUNET_free (ctx);
}

References ctx, GNUNET_ERROR_TYPE_DEBUG, GNUNET_free, GNUNET_log_strerror, GNUNET_NETWORK_fdset_isset(), GNUNET_NETWORK_socket_close(), GNUNET_NETWORK_socket_send(), GNUNET_NETWORK_socket_shutdown(), GNUNET_SCHEDULER_get_task_context(), tc, and GNUNET_SCHEDULER_TaskContext::write_ready.

Referenced by try_send_tcp().

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try_send_tcp()

static void try_send_tcp ( uint32_t  dst_ipv4, uint16_t  dport, uint16_t  data  )

static

Try to send data to the IP dst_ipv4' at port dport via TCP.

Parameters

dst_ipv4	target IP
dport	target port
data	data to send

Definition at line 162 of file gnunet-nat-server.c.

{
  struct GNUNET_NETWORK_Handle *s;
  struct sockaddr_in sa;
  struct TcpContext *ctx;
 
  s = GNUNET_NETWORK_socket_create (AF_INET,
                                    SOCK_STREAM,
                                    0);
  if (NULL == s)
  {
    GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
                         "socket");
    return;
  }
  memset (&sa, 0, sizeof(sa));
  sa.sin_family = AF_INET;
#if HAVE_SOCKADDR_IN_SIN_LEN
  sa.sin_len = sizeof(sa);
#endif
  sa.sin_addr.s_addr = dst_ipv4;
  sa.sin_port = htons (dport);
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Sending TCP message to `%s'\n",
              GNUNET_a2s ((struct sockaddr *) &sa,
                          sizeof(sa)));
  if ((GNUNET_OK !=
       GNUNET_NETWORK_socket_connect (s,
                                      (const struct sockaddr *) &sa,
                                      sizeof(sa))) &&
      (errno != EINPROGRESS))
  {
    GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
                         "connect");
    GNUNET_NETWORK_socket_close (s);
    return;
  }
  ctx = GNUNET_new (struct TcpContext);
  ctx->s = s;
  ctx->data = data;
  GNUNET_SCHEDULER_add_write_net (GNUNET_TIME_UNIT_SECONDS,
                                  s,
                                  &tcp_send,
                                  ctx);
}

References ctx, data, GNUNET_a2s(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_ERROR_TYPE_WARNING, GNUNET_log, GNUNET_log_strerror, GNUNET_NETWORK_socket_close(), GNUNET_NETWORK_socket_connect(), GNUNET_NETWORK_socket_create(), GNUNET_new, GNUNET_OK, GNUNET_SCHEDULER_add_write_net(), GNUNET_TIME_UNIT_SECONDS, TcpContext::s, and tcp_send().

Referenced by handle_test().

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try_send_udp()

static void try_send_udp ( uint32_t  dst_ipv4, uint16_t  dport, uint16_t  data  )

static

Try to send data to the IP dst_ipv4 at port dport via UDP.

Parameters

dst_ipv4	target IP
dport	target port
data	data to send

Definition at line 220 of file gnunet-nat-server.c.

{
  struct GNUNET_NETWORK_Handle *s;
  struct sockaddr_in sa;
 
  s = GNUNET_NETWORK_socket_create (AF_INET,
                                    SOCK_DGRAM,
                                    0);
  if (NULL == s)
  {
    GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
                         "socket");
    return;
  }
  memset (&sa, 0, sizeof(sa));
  sa.sin_family = AF_INET;
#if HAVE_SOCKADDR_IN_SIN_LEN
  sa.sin_len = sizeof(sa);
#endif
  sa.sin_addr.s_addr = dst_ipv4;
  sa.sin_port = htons (dport);
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Sending UDP packet to `%s'\n",
              GNUNET_a2s ((struct sockaddr *) &sa,
                          sizeof(sa)));
  if (-1 ==
      GNUNET_NETWORK_socket_sendto (s,
                                    &data,
                                    sizeof(data),
                                    (const struct sockaddr *) &sa,
                                    sizeof(sa)))
    GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
                         "sendto");
  GNUNET_NETWORK_socket_close (s);
}

References data, GNUNET_a2s(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_ERROR_TYPE_WARNING, GNUNET_log, GNUNET_log_strerror, GNUNET_NETWORK_socket_close(), GNUNET_NETWORK_socket_create(), and GNUNET_NETWORK_socket_sendto().

Referenced by handle_test().

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handle_test()

static void handle_test ( void *  cls, const struct GNUNET_NAT_AUTO_TestMessage *  tm  )

static

We've received a request to probe a NAT traversal.

Do it.

Parameters

cls	handle to client (we always close)
tm	message with details about what to test

Definition at line 267 of file gnunet-nat-server.c.

{
  struct ClientData *cd = cls;
  uint16_t dport;
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Received test request\n");
  dport = ntohs (tm->dport);
  if (0 == dport)
    try_anat (tm->dst_ipv4,
              ntohs (tm->data),
              (int) ntohl (tm->is_tcp));
  else if (GNUNET_YES == ntohl (tm->is_tcp))
    try_send_tcp (tm->dst_ipv4,
                  dport,
                  tm->data);
  else
    try_send_udp (tm->dst_ipv4,
                  dport,
                  tm->data);
  GNUNET_SERVICE_client_drop (cd->client);
}

References ClientData::client, GNUNET_NAT_AUTO_TestMessage::data, GNUNET_NAT_AUTO_TestMessage::dport, GNUNET_NAT_AUTO_TestMessage::dst_ipv4, GNUNET_ERROR_TYPE_DEBUG, GNUNET_log, GNUNET_SERVICE_client_drop(), GNUNET_YES, GNUNET_NAT_AUTO_TestMessage::is_tcp, try_anat(), try_send_tcp(), and try_send_udp().

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run()

static void run ( void *  cls, const struct GNUNET_CONFIGURATION_Handle *  c, struct GNUNET_SERVICE_Handle *  srv  )

static

Main function that will be run.

Parameters

cls	closure
c	configuration
srv	service handle

Definition at line 300 of file gnunet-nat-server.c.

{
  cfg = c;
}

References cfg.

force_timeout()

static void force_timeout ( void *  cls )

static

Forcefully drops client after 1s.

Parameters

cls	our struct ClientData of a client to drop

Definition at line 314 of file gnunet-nat-server.c.

{
  struct ClientData *cd = cls;
 
  cd->tt = NULL;
  GNUNET_SERVICE_client_drop (cd->client);
}

References ClientData::client, GNUNET_SERVICE_client_drop(), and ClientData::tt.

Referenced by client_connect_cb().

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client_connect_cb()

static void* client_connect_cb ( void *  cls, struct GNUNET_SERVICE_Client *  c, struct GNUNET_MQ_Handle *  mq  )

static

Callback called when a client connects to the service.

Parameters

cls	closure for the service
c	the new client that connected to the service
mq	the message queue used to send messages to the client

Returns

our struct ClientData

Definition at line 332 of file gnunet-nat-server.c.

{
  struct ClientData *cd;
 
  cd = GNUNET_new (struct ClientData);
  cd->client = c;
  cd->tt = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS,
                                         &force_timeout,
                                         cd);
  return cd;
}

References ClientData::client, force_timeout(), GNUNET_new, GNUNET_SCHEDULER_add_delayed(), GNUNET_TIME_UNIT_SECONDS, and ClientData::tt.

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client_disconnect_cb()

static void client_disconnect_cb ( void *  cls, struct GNUNET_SERVICE_Client *  c, void *  internal_cls  )

static

Callback called when a client disconnected from the service.

Parameters

cls	closure for the service
c	the client that disconnected
internal_cls	our struct ClientData

Definition at line 355 of file gnunet-nat-server.c.

{
  struct ClientData *cd = internal_cls;
 
  if (NULL != cd->tt)
    GNUNET_SCHEDULER_cancel (cd->tt);
  GNUNET_free (cd);
}

References GNUNET_free, GNUNET_SCHEDULER_cancel(), and ClientData::tt.

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GNUNET_SERVICE_MAIN()

GNUNET_SERVICE_MAIN	(	"nat-server"	,
		GNUNET_SERVICE_OPTION_NONE	,
		&	run,
		&	client_connect_cb,
		&	client_disconnect_cb,
		NULL	,
		GNUNET_MQ_hd_fixed_size(test, GNUNET_MESSAGE_TYPE_NAT_TEST, struct GNUNET_NAT_AUTO_TestMessage, NULL)	,
		GNUNET_MQ_handler_end()
	)

Define "main" method using service macro.

Variable Documentation

cfg

const struct GNUNET_CONFIGURATION_Handle* cfg

static

Our configuration.

Definition at line 53 of file gnunet-nat-server.c.

Referenced by run(), and try_anat().