vpn_api.c File Reference

library to access the VPN service and tell it how to redirect traffic More...

#include "platform.h"
#include "gnunet_vpn_service.h"
#include "vpn.h"

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Data Structures
struct	GNUNET_VPN_Handle
	Opaque VPN handle. More...
struct	GNUNET_VPN_RedirectionRequest
	Opaque redirection request handle. More...

Functions
static void	reconnect (struct GNUNET_VPN_Handle *vh)
	Disconnect from the service (communication error) and reconnect later. More...
static int	check_use_ip (void *cls, const struct RedirectToIpResponseMessage *rm)
	Check a GNUNET_MESSAGE_TYPE_VPN_CLIENT_USE_IP message from the VPN service. More...
static void	handle_use_ip (void *cls, const struct RedirectToIpResponseMessage *rm)
	Handle a GNUNET_MESSAGE_TYPE_VPN_CLIENT_USE_IP message from the VPN service. More...
static void	send_request (struct GNUNET_VPN_RedirectionRequest *rr)
	Add a request to our request queue and transmit it. More...
static void	mq_error_handler (void *cls, enum GNUNET_MQ_Error error)
	Generic error handler, called with the appropriate error code and the same closure specified at the creation of the message queue. More...
static void	connect_task (void *cls)
	Connect to the VPN service and start again to transmit our requests. More...
void	GNUNET_VPN_cancel_request (struct GNUNET_VPN_RedirectionRequest *rr)
	Cancel redirection request with the service. More...
struct GNUNET_VPN_RedirectionRequest *	GNUNET_VPN_redirect_to_peer (struct GNUNET_VPN_Handle *vh, int result_af, uint8_t protocol, const struct GNUNET_PeerIdentity *peer, const struct GNUNET_HashCode *serv, struct GNUNET_TIME_Absolute expiration_time, GNUNET_VPN_AllocationCallback cb, void *cb_cls)
	Tell the VPN that a forwarding to a particular peer offering a particular service is requested. More...
struct GNUNET_VPN_RedirectionRequest *	GNUNET_VPN_redirect_to_ip (struct GNUNET_VPN_Handle *vh, int result_af, int addr_af, const void *addr, struct GNUNET_TIME_Absolute expiration_time, GNUNET_VPN_AllocationCallback cb, void *cb_cls)
	Tell the VPN that forwarding to the Internet via some exit node is requested. More...
struct GNUNET_VPN_Handle *	GNUNET_VPN_connect (const struct GNUNET_CONFIGURATION_Handle *cfg)
	Connect to the VPN service. More...
void	GNUNET_VPN_disconnect (struct GNUNET_VPN_Handle *vh)
	Disconnect from the VPN service. More...

Detailed Description

library to access the VPN service and tell it how to redirect traffic

Author

Christian Grothoff

Definition in file vpn_api.c.

Function Documentation

reconnect()

static void reconnect ( struct GNUNET_VPN_Handle *  vh )

static

Disconnect from the service (communication error) and reconnect later.

Parameters

vh	handle to reconnect.

Definition at line 348 of file vpn_api.c.

{
  struct GNUNET_VPN_RedirectionRequest *rr;
 
  GNUNET_MQ_destroy (vh->mq);
  vh->mq = NULL;
  vh->request_id_gen = 0;
  for (rr = vh->rr_head; NULL != rr; rr = rr->next)
    rr->request_id = 0;
  vh->backoff = GNUNET_TIME_relative_max (GNUNET_TIME_UNIT_MILLISECONDS,
                                          GNUNET_TIME_relative_min (
                                            GNUNET_TIME_relative_saturating_multiply (
                                              vh->backoff, 2),
                                            GNUNET_TIME_relative_multiply (
                                              GNUNET_TIME_UNIT_SECONDS, 30)));
  vh->rt = GNUNET_SCHEDULER_add_delayed (vh->backoff,
                                         &connect_task,
                                         vh);
}

References GNUNET_VPN_Handle::backoff, connect_task(), GNUNET_MQ_destroy(), GNUNET_SCHEDULER_add_delayed(), GNUNET_TIME_relative_max(), GNUNET_TIME_relative_min(), GNUNET_TIME_relative_multiply(), GNUNET_TIME_relative_saturating_multiply(), GNUNET_TIME_UNIT_MILLISECONDS, GNUNET_TIME_UNIT_SECONDS, GNUNET_VPN_Handle::mq, GNUNET_VPN_RedirectionRequest::next, GNUNET_VPN_RedirectionRequest::request_id, GNUNET_VPN_Handle::request_id_gen, GNUNET_VPN_Handle::rr_head, GNUNET_VPN_Handle::rt, and GNUNET_VPN_RedirectionRequest::vh.

Referenced by mq_error_handler().

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check_use_ip()

static int check_use_ip ( void *  cls, const struct RedirectToIpResponseMessage *  rm  )

static

Check a GNUNET_MESSAGE_TYPE_VPN_CLIENT_USE_IP message from the VPN service.

Parameters

cls	the struct GNUNET_VPN_Handle
rm	message received

Returns

GNUNET_OK if rm is well-formed

Definition at line 164 of file vpn_api.c.

{
  size_t alen;
  int af;
 
  af = (int) ntohl (rm->result_af);
  switch (af)
  {
  case AF_UNSPEC:
    alen = 0;
    break;
 
  case AF_INET:
    alen = sizeof(struct in_addr);
    break;
 
  case AF_INET6:
    alen = sizeof(struct in6_addr);
    break;
 
  default:
    GNUNET_break (0);
    return GNUNET_SYSERR;
  }
  if ((ntohs (rm->header.size) != alen + sizeof(*rm)) ||
      (0 == rm->request_id))
  {
    GNUNET_break (0);
    return GNUNET_SYSERR;
  }
  return GNUNET_OK;
}

References GNUNET_break, GNUNET_OK, GNUNET_SYSERR, RedirectToIpResponseMessage::header, consensus-simulation::int, RedirectToIpResponseMessage::request_id, RedirectToIpResponseMessage::result_af, and GNUNET_MessageHeader::size.

handle_use_ip()

static void handle_use_ip ( void *  cls, const struct RedirectToIpResponseMessage *  rm  )

static

Handle a GNUNET_MESSAGE_TYPE_VPN_CLIENT_USE_IP message from the VPN service.

Parameters

cls	the struct GNUNET_VPN_Handle
rm	message received

Definition at line 207 of file vpn_api.c.

{
  struct GNUNET_VPN_Handle *vh = cls;
  struct GNUNET_VPN_RedirectionRequest *rr;
  int af;
 
  af = (int) ntohl (rm->result_af);
  for (rr = vh->rr_head; NULL != rr; rr = rr->next)
  {
    if (rr->request_id == rm->request_id)
    {
      GNUNET_CONTAINER_DLL_remove (vh->rr_head,
                                   vh->rr_tail,
                                   rr);
      rr->cb (rr->cb_cls,
              af,
              (af == AF_UNSPEC) ? NULL : &rm[1]);
      GNUNET_free (rr);
      break;
    }
  }
}

References GNUNET_VPN_RedirectionRequest::cb, GNUNET_VPN_RedirectionRequest::cb_cls, GNUNET_CONTAINER_DLL_remove, GNUNET_free, consensus-simulation::int, GNUNET_VPN_RedirectionRequest::next, RedirectToIpResponseMessage::request_id, GNUNET_VPN_RedirectionRequest::request_id, RedirectToIpResponseMessage::result_af, GNUNET_VPN_Handle::rr_head, GNUNET_VPN_Handle::rr_tail, and GNUNET_VPN_RedirectionRequest::vh.

send_request()

static void send_request ( struct GNUNET_VPN_RedirectionRequest *  rr )

static

Add a request to our request queue and transmit it.

Parameters

rr	request to queue and transmit.

Definition at line 238 of file vpn_api.c.

{
  struct GNUNET_VPN_Handle *vh = rr->vh;
  struct RedirectToIpRequestMessage *rip;
  struct RedirectToServiceRequestMessage *rs;
  struct GNUNET_MQ_Envelope *env;
  size_t alen;
 
  if (NULL == vh->mq)
    return;
  if (NULL == rr->addr)
  {
    env = GNUNET_MQ_msg (rs,
                         GNUNET_MESSAGE_TYPE_VPN_CLIENT_REDIRECT_TO_SERVICE);
    rs->reserved = htonl (0);
    rs->expiration_time = GNUNET_TIME_absolute_hton (rr->expiration_time);
    rs->protocol = htonl (rr->protocol);
    rs->result_af = htonl (rr->result_af);
    rs->target = rr->peer;
    rs->service_descriptor = rr->serv;
    rs->request_id = rr->request_id = ++vh->request_id_gen;
  }
  else
  {
    switch (rr->addr_af)
    {
    case AF_INET:
      alen = sizeof(struct in_addr);
      break;
 
    case AF_INET6:
      alen = sizeof(struct in6_addr);
      break;
 
    default:
      GNUNET_assert (0);
      return;
    }
    env = GNUNET_MQ_msg_extra (rip,
                               alen,
                               GNUNET_MESSAGE_TYPE_VPN_CLIENT_REDIRECT_TO_IP);
    rip->reserved = htonl (0);
    rip->expiration_time = GNUNET_TIME_absolute_hton (rr->expiration_time);
    rip->result_af = htonl (rr->result_af);
    rip->addr_af = htonl (rr->addr_af);
    rip->request_id = rr->request_id = ++vh->request_id_gen;
    GNUNET_memcpy (&rip[1],
                   rr->addr,
                   alen);
  }
  GNUNET_MQ_send (vh->mq,
                  env);
}

References GNUNET_VPN_RedirectionRequest::addr, RedirectToIpRequestMessage::addr_af, GNUNET_VPN_RedirectionRequest::addr_af, env, RedirectToIpRequestMessage::expiration_time, RedirectToServiceRequestMessage::expiration_time, GNUNET_VPN_RedirectionRequest::expiration_time, GNUNET_assert, GNUNET_memcpy, GNUNET_MESSAGE_TYPE_VPN_CLIENT_REDIRECT_TO_IP, GNUNET_MESSAGE_TYPE_VPN_CLIENT_REDIRECT_TO_SERVICE, GNUNET_MQ_msg, GNUNET_MQ_msg_extra, GNUNET_MQ_send(), GNUNET_TIME_absolute_hton(), GNUNET_VPN_Handle::mq, GNUNET_VPN_RedirectionRequest::peer, RedirectToServiceRequestMessage::protocol, GNUNET_VPN_RedirectionRequest::protocol, RedirectToIpRequestMessage::request_id, RedirectToServiceRequestMessage::request_id, GNUNET_VPN_RedirectionRequest::request_id, GNUNET_VPN_Handle::request_id_gen, RedirectToIpRequestMessage::reserved, RedirectToServiceRequestMessage::reserved, RedirectToIpRequestMessage::result_af, RedirectToServiceRequestMessage::result_af, GNUNET_VPN_RedirectionRequest::result_af, GNUNET_VPN_RedirectionRequest::serv, RedirectToServiceRequestMessage::service_descriptor, RedirectToServiceRequestMessage::target, and GNUNET_VPN_RedirectionRequest::vh.

Referenced by connect_task(), GNUNET_VPN_redirect_to_ip(), and GNUNET_VPN_redirect_to_peer().

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mq_error_handler()

static void mq_error_handler ( void *  cls, enum GNUNET_MQ_Error  error  )

static

Generic error handler, called with the appropriate error code and the same closure specified at the creation of the message queue.

Not every message queue implementation supports an error handler.

Parameters

cls	closure with the struct GNUNET_VPN_Handle *
error	error code

Definition at line 302 of file vpn_api.c.

{
  struct GNUNET_VPN_Handle *vh = cls;
 
  reconnect (vh);
}

References reconnect().

Referenced by connect_task().

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connect_task()

static void connect_task ( void *  cls )

static

Connect to the VPN service and start again to transmit our requests.

Parameters

cls	the struct GNUNET_VPN_Handle *

Definition at line 317 of file vpn_api.c.

{
  struct GNUNET_VPN_Handle *vh = cls;
  struct GNUNET_MQ_MessageHandler handlers[] = {
    GNUNET_MQ_hd_var_size (use_ip,
                           GNUNET_MESSAGE_TYPE_VPN_CLIENT_USE_IP,
                           struct RedirectToIpResponseMessage,
                           cls),
    GNUNET_MQ_handler_end ()
  };
  struct GNUNET_VPN_RedirectionRequest *rr;
 
  vh->rt = NULL;
  vh->mq = GNUNET_CLIENT_connect (vh->cfg,
                                  "vpn",
                                  handlers,
                                  &mq_error_handler,
                                  vh);
  if (NULL == vh->mq)
    return;
  for (rr = vh->rr_head; NULL != rr; rr = rr->next)
    send_request (rr);
}

References GNUNET_VPN_Handle::cfg, GNUNET_MQ_MessageHandler::cls, GNUNET_CLIENT_connect(), GNUNET_MESSAGE_TYPE_VPN_CLIENT_USE_IP, GNUNET_MQ_handler_end, GNUNET_MQ_hd_var_size, handlers, GNUNET_VPN_Handle::mq, mq_error_handler(), GNUNET_VPN_RedirectionRequest::next, GNUNET_VPN_Handle::rr_head, GNUNET_VPN_Handle::rt, send_request(), and GNUNET_VPN_RedirectionRequest::vh.

Referenced by GNUNET_VPN_connect(), and reconnect().

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