GNUnet  0.19.2
gnunet-daemon-pt.c File Reference

tool to manipulate DNS and VPN services to perform protocol translation (IPvX over GNUnet) More...

Include dependency graph for gnunet-daemon-pt.c:

Go to the source code of this file.

Data Structures

struct  ReplyContext
 Information tracked per DNS reply that we are processing. More...
 
struct  CadetExit
 Handle to a peer that advertised that it is willing to serve as a DNS exit. More...
 
struct  RequestContext
 State we keep for a request that is going out via CADET. More...
 
struct  DnsResponseMessage
 Message with a DNS response. More...
 

Macros

#define TIMEOUT   GNUNET_TIME_UNIT_MINUTES
 After how long do we time out if we could not get an IP from VPN or CADET? More...
 
#define MAX_DNS_SIZE   (8 * 1024)
 How many bytes of payload do we allow at most for a DNS reply? Given that this is pretty much limited to loopback, we can be pretty high (Linux loopback defaults to 16k, most local UDP packets should survive up to 9k (NFS), so 8k should be pretty safe in general). More...
 
#define MAX_OPEN_TUNNELS   4
 How many channels do we open at most at the same time? More...
 

Enumerations

enum  RequestGroup { ANSWERS = 0 , AUTHORITY_RECORDS = 1 , ADDITIONAL_RECORDS = 2 , END = 3 }
 Which group of DNS records are we currently processing? More...
 

Functions

static void try_open_exit (void)
 We are short on cadet exits, try to open another one. More...
 
static uint32_t get_channel_weight (struct CadetExit *exit)
 Compute the weight of the given exit. More...
 
static struct CadetExitchoose_exit ()
 Choose a cadet exit for a DNS request. More...
 
static void finish_request (struct ReplyContext *rc)
 We're done modifying all records in the response. More...
 
static void submit_request (struct ReplyContext *rc)
 Process the next record of the given request context. More...
 
static void vpn_allocation_callback (void *cls, int af, const void *address)
 Callback invoked from the VPN service once a redirection is available. More...
 
static void modify_address (struct ReplyContext *rc, struct GNUNET_DNSPARSER_Record *rec)
 Modify the given DNS record by asking VPN to create a channel to the given address. More...
 
static int work_test (const struct GNUNET_DNSPARSER_Record *ra, unsigned int ra_len)
 Test if any of the given records need protocol-translation work. More...
 
static void dns_post_request_handler (void *cls, struct GNUNET_DNS_RequestHandle *rh, size_t request_length, const char *request)
 This function is called AFTER we got an IP address for a DNS request. More...
 
static void timeout_request (void *cls)
 Task run if the time to answer a DNS request via CADET is over. More...
 
static void dns_pre_request_handler (void *cls, struct GNUNET_DNS_RequestHandle *rh, size_t request_length, const char *request)
 This function is called before the DNS request has been given to a "local" DNS resolver. More...
 
static GNUNET_NETWORK_STRUCT_END int check_dns_response (void *cls, const struct DnsResponseMessage *msg)
 Process a request via cadet to perform a DNS query. More...
 
static void handle_dns_response (void *cls, const struct DnsResponseMessage *msg)
 Process a request via cadet to perform a DNS query. More...
 
static void abort_all_requests (struct CadetExit *exit)
 Abort all pending DNS requests with the given cadet exit. More...
 
static void cleanup (void *cls)
 Function scheduled as very last function, cleans up after us. More...
 
static void cadet_channel_end_cb (void *cls, const struct GNUNET_CADET_Channel *channel)
 Function called whenever a channel is destroyed. More...
 
static void channel_idle_notify_cb (void *cls, const struct GNUNET_CADET_Channel *channel, int window_size)
 Function called whenever a channel has excess capacity. More...
 
static void handle_dht_result (void *cls, struct GNUNET_TIME_Absolute exp, const struct GNUNET_HashCode *key, const struct GNUNET_PeerIdentity *trunc_peer, const struct GNUNET_DHT_PathElement *get_path, unsigned int get_path_length, const struct GNUNET_DHT_PathElement *put_path, unsigned int put_path_length, enum GNUNET_BLOCK_Type type, size_t size, const void *data)
 Function called whenever we find an advertisement for a DNS exit in the DHT. More...
 
static void run (void *cls, char *const *args, const char *cfgfile, const struct GNUNET_CONFIGURATION_Handle *cfg_)
 Main function that will be run by the scheduler. More...
 
int main (int argc, char *const *argv)
 The main function. More...
 

Variables

static struct CadetExitexit_head
 Head of DLL of cadet exits. More...
 
static struct CadetExitexit_tail
 Tail of DLL of cadet exits. More...
 
static const struct GNUNET_CONFIGURATION_Handlecfg
 The handle to the configuration used throughout the process. More...
 
static struct GNUNET_VPN_Handlevpn_handle
 The handle to the VPN. More...
 
static struct GNUNET_CADET_Handlecadet_handle
 The handle to the CADET service. More...
 
static struct GNUNET_STATISTICS_Handlestats
 Statistics. More...
 
static struct GNUNET_DNS_Handledns_post_handle
 The handle to DNS post-resolution modifications. More...
 
static struct GNUNET_DNS_Handledns_pre_handle
 The handle to DNS pre-resolution modifications. More...
 
static struct GNUNET_DHT_Handledht
 Handle to access the DHT. More...
 
static struct GNUNET_DHT_GetHandledht_get
 Our DHT GET operation to find DNS exits. More...
 
static int ipv4_pt
 Are we doing IPv4-pt? More...
 
static int ipv6_pt
 Are we doing IPv6-pt? More...
 
static int dns_channel
 Are we channeling DNS queries? More...
 
static unsigned int dns_exit_available
 Number of DNS exit peers we currently have in the cadet channel. More...
 

Detailed Description

tool to manipulate DNS and VPN services to perform protocol translation (IPvX over GNUnet)

Author
Christian Grothoff

Definition in file gnunet-daemon-pt.c.

Macro Definition Documentation

◆ TIMEOUT

#define TIMEOUT   GNUNET_TIME_UNIT_MINUTES

After how long do we time out if we could not get an IP from VPN or CADET?

Definition at line 39 of file gnunet-daemon-pt.c.

◆ MAX_DNS_SIZE

#define MAX_DNS_SIZE   (8 * 1024)

How many bytes of payload do we allow at most for a DNS reply? Given that this is pretty much limited to loopback, we can be pretty high (Linux loopback defaults to 16k, most local UDP packets should survive up to 9k (NFS), so 8k should be pretty safe in general).

Definition at line 48 of file gnunet-daemon-pt.c.

◆ MAX_OPEN_TUNNELS

#define MAX_OPEN_TUNNELS   4

How many channels do we open at most at the same time?

Definition at line 53 of file gnunet-daemon-pt.c.

Enumeration Type Documentation

◆ RequestGroup

Which group of DNS records are we currently processing?

Enumerator
ANSWERS 

DNS answers.

AUTHORITY_RECORDS 

DNS authority records.

ADDITIONAL_RECORDS 

DNS additional records.

END 

We're done processing.

Definition at line 59 of file gnunet-daemon-pt.c.

60 {
64  ANSWERS = 0,
65 
70 
75 
79  END = 3
80 };
@ ANSWERS
DNS answers.
@ ADDITIONAL_RECORDS
DNS additional records.
@ END
We're done processing.
@ AUTHORITY_RECORDS
DNS authority records.

Function Documentation

◆ try_open_exit()

static void try_open_exit ( void  )
static

We are short on cadet exits, try to open another one.

Definition at line 1052 of file gnunet-daemon-pt.c.

1053 {
1054  struct CadetExit *pos;
1055  uint32_t candidate_count;
1056  uint32_t candidate_selected;
1057  struct GNUNET_HashCode port;
1058 
1061  &port);
1062  candidate_count = 0;
1063  for (pos = exit_head; NULL != pos; pos = pos->next)
1064  if (NULL == pos->cadet_channel)
1065  candidate_count++;
1066  if (0 == candidate_count)
1067  {
1069  "No DNS exits available yet.\n");
1070  return;
1071  }
1073  candidate_count);
1074  candidate_count = 0;
1075  for (pos = exit_head; NULL != pos; pos = pos->next)
1076  if (NULL == pos->cadet_channel)
1077  {
1078  candidate_count++;
1079  if (candidate_selected < candidate_count)
1080  {
1081  struct GNUNET_MQ_MessageHandler cadet_handlers[] = {
1082  GNUNET_MQ_hd_var_size (dns_response,
1084  struct DnsResponseMessage,
1085  pos),
1087  };
1088 
1089 
1090  /* move to the head of the DLL */
1091  pos->cadet_channel
1093  pos,
1094  &pos->peer,
1095  &port,
1098  cadet_handlers);
1099  if (NULL == pos->cadet_channel)
1100  {
1101  GNUNET_break (0);
1102  continue;
1103  }
1105  exit_tail,
1106  pos);
1108  exit_tail,
1109  pos);
1111  return;
1112  }
1113  }
1114  GNUNET_assert (NULL == exit_head);
1115 }
static uint16_t port
Port number.
Definition: gnunet-bcd.c:147
static struct CadetExit * exit_head
Head of DLL of cadet exits.
static unsigned int dns_exit_available
Number of DNS exit peers we currently have in the cadet channel.
static void channel_idle_notify_cb(void *cls, const struct GNUNET_CADET_Channel *channel, int window_size)
Function called whenever a channel has excess capacity.
static struct GNUNET_CADET_Handle * cadet_handle
The handle to the CADET service.
static struct CadetExit * exit_tail
Tail of DLL of cadet exits.
static void cadet_channel_end_cb(void *cls, const struct GNUNET_CADET_Channel *channel)
Function called whenever a channel is destroyed.
#define GNUNET_APPLICATION_PORT_INTERNET_RESOLVER
Internet DNS resolution (external DNS gateway).
struct GNUNET_CADET_Channel * GNUNET_CADET_channel_create(struct GNUNET_CADET_Handle *h, void *channel_cls, const struct GNUNET_PeerIdentity *destination, const struct GNUNET_HashCode *port, GNUNET_CADET_WindowSizeEventHandler window_changes, GNUNET_CADET_DisconnectEventHandler disconnects, const struct GNUNET_MQ_MessageHandler *handlers)
Create a new channel towards a remote peer.
Definition: cadet_api.c:1015
uint32_t GNUNET_CRYPTO_random_u32(enum GNUNET_CRYPTO_Quality mode, uint32_t i)
Produce a random value.
@ GNUNET_CRYPTO_QUALITY_WEAK
No good quality of the operation is needed (i.e., random numbers can be pseudo-random).
#define GNUNET_CONTAINER_DLL_remove(head, tail, element)
Remove an element from a DLL.
#define GNUNET_CONTAINER_DLL_insert(head, tail, element)
Insert an element at the head of a DLL.
void GNUNET_CRYPTO_hash(const void *block, size_t size, struct GNUNET_HashCode *ret)
Compute hash of a given block.
Definition: crypto_hash.c:41
#define GNUNET_log(kind,...)
#define GNUNET_assert(cond)
Use this for fatal errors that cannot be handled.
#define GNUNET_break(cond)
Use this for internal assertion violations that are not fatal (can be handled) but should not occur.
@ GNUNET_ERROR_TYPE_WARNING
#define GNUNET_MQ_handler_end()
End-marker for the handlers array.
#define GNUNET_MQ_hd_var_size(name, code, str, ctx)
#define GNUNET_MESSAGE_TYPE_VPN_DNS_FROM_INTERNET
Type of messages containing an DNS reply from a DNS exit service.
Handle to a peer that advertised that it is willing to serve as a DNS exit.
struct CadetExit * next
Kept in a DLL.
struct GNUNET_CADET_Channel * cadet_channel
Channel we use for DNS requests over CADET, NULL if we did not initialize a channel to this peer yet.
struct GNUNET_PeerIdentity peer
Identity of the peer that is providing the exit for us.
Message with a DNS response.
A 512-bit hashcode.
Message handler for a specific message type.

References CadetExit::cadet_channel, cadet_channel_end_cb(), cadet_handle, channel_idle_notify_cb(), dns_exit_available, exit_head, exit_tail, GNUNET_APPLICATION_PORT_INTERNET_RESOLVER, GNUNET_assert, GNUNET_break, GNUNET_CADET_channel_create(), GNUNET_CONTAINER_DLL_insert, GNUNET_CONTAINER_DLL_remove, GNUNET_CRYPTO_hash(), GNUNET_CRYPTO_QUALITY_WEAK, GNUNET_CRYPTO_random_u32(), GNUNET_ERROR_TYPE_WARNING, GNUNET_log, GNUNET_MESSAGE_TYPE_VPN_DNS_FROM_INTERNET, GNUNET_MQ_handler_end, GNUNET_MQ_hd_var_size, CadetExit::next, CadetExit::peer, and port.

Referenced by cadet_channel_end_cb(), handle_dht_result(), and timeout_request().

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◆ get_channel_weight()

static uint32_t get_channel_weight ( struct CadetExit exit)
static

Compute the weight of the given exit.

The higher the weight, the more likely it will be that the channel will be chosen. A weigt of zero means that we should close the channel as it is so bad, that we should not use it.

Parameters
exitexit to calculate the weight for
Returns
weight of the channel

Definition at line 319 of file gnunet-daemon-pt.c.

320 {
321  uint32_t dropped;
322  uint32_t drop_percent;
323  uint32_t good_percent;
324 
325  GNUNET_assert (exit->num_transmitted >= exit->num_answered);
326  dropped = exit->num_transmitted - exit->num_answered;
327  if (exit->num_transmitted > 0)
328  drop_percent = (uint32_t) ((100LL * dropped) / exit->num_transmitted);
329  else
330  drop_percent = 50; /* no data */
331  if ((exit->num_transmitted > 20) &&
332  (drop_percent > 25))
333  return 0; /* statistically significant, and > 25% loss, die */
334  good_percent = 100 - drop_percent;
335  GNUNET_assert (0 != good_percent);
336  if (UINT32_MAX / good_percent / good_percent < exit->num_transmitted)
337  return UINT32_MAX; /* formula below would overflow */
338  return 1 + good_percent * good_percent * exit->num_transmitted;
339 }
unsigned long long drop_percent
Set to non-zero values to create random drops to test retransmissions.
unsigned int num_answered
How many DNS requests were answered via this channel?
unsigned int num_transmitted
How many DNS requests did we transmit via this channel?

References drop_percent, GNUNET_assert, CadetExit::num_answered, and CadetExit::num_transmitted.

Referenced by choose_exit(), and timeout_request().

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◆ choose_exit()

static struct CadetExit* choose_exit ( )
static

Choose a cadet exit for a DNS request.

We try to use a channel that is reliable and currently available. All existing channels are given a base weight of 1, plus a score relating to the total number of queries answered in relation to the total number of queries we sent to that channel. That score is doubled if the channel is currently idle.

Returns
NULL if no exit is known, otherwise the exit that we should use to queue a message with

Definition at line 354 of file gnunet-daemon-pt.c.

355 {
356  struct CadetExit *pos;
357  uint64_t total_transmitted;
358  uint64_t selected_offset;
359  uint32_t channel_weight;
360 
361  total_transmitted = 0;
362  for (pos = exit_head; NULL != pos; pos = pos->next)
363  {
364  if (NULL == pos->cadet_channel)
365  break;
366  channel_weight = get_channel_weight (pos);
367  total_transmitted += channel_weight;
368  /* double weight for idle channels */
369  if (0 != pos->idle)
370  total_transmitted += channel_weight;
371  }
372  if (0 == total_transmitted)
373  {
374  /* no channels available, or only a very bad one... */
375  return exit_head;
376  }
378  total_transmitted);
379  total_transmitted = 0;
380  for (pos = exit_head; NULL != pos; pos = pos->next)
381  {
382  if (NULL == pos->cadet_channel)
383  break;
384  channel_weight = get_channel_weight (pos);
385  total_transmitted += channel_weight;
386  /* double weight for idle channels */
387  if (0 != pos->idle)
388  total_transmitted += channel_weight;
389  if (total_transmitted > selected_offset)
390  return pos;
391  }
392  GNUNET_break (0);
393  return NULL;
394 }
static uint32_t get_channel_weight(struct CadetExit *exit)
Compute the weight of the given exit.
uint64_t GNUNET_CRYPTO_random_u64(enum GNUNET_CRYPTO_Quality mode, uint64_t max)
Generate a random unsigned 64-bit value.
int idle
Size of the window, 0 if we are busy.

References CadetExit::cadet_channel, exit_head, get_channel_weight(), GNUNET_break, GNUNET_CRYPTO_QUALITY_WEAK, GNUNET_CRYPTO_random_u64(), CadetExit::idle, and CadetExit::next.

Referenced by cadet_channel_end_cb(), and dns_pre_request_handler().

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◆ finish_request()

static void finish_request ( struct ReplyContext rc)
static

We're done modifying all records in the response.

Submit the reply and free the resources of the rc.

Parameters
rccontext to process

Definition at line 404 of file gnunet-daemon-pt.c.

405 {
406  char *buf;
407  size_t buf_len;
408 
409  if (GNUNET_SYSERR ==
411  MAX_DNS_SIZE,
412  &buf,
413  &buf_len))
414  {
416  _ ("Failed to pack DNS request. Dropping.\n"));
418  }
419  else
420  {
422  gettext_noop ("# DNS requests mapped to VPN"),
423  1, GNUNET_NO);
425  buf_len,
426  buf);
427  GNUNET_free (buf);
428  }
430  GNUNET_free (rc);
431 }
#define gettext_noop(String)
Definition: gettext.h:70
static struct GNUNET_STATISTICS_Handle * stats
Statistics.
#define MAX_DNS_SIZE
How many bytes of payload do we allow at most for a DNS reply? Given that this is pretty much limited...
static char buf[2048]
void GNUNET_DNSPARSER_free_packet(struct GNUNET_DNSPARSER_Packet *p)
Free memory taken by a packet.
Definition: dnsparser.c:854
int GNUNET_DNSPARSER_pack(const struct GNUNET_DNSPARSER_Packet *p, uint16_t max, char **buf, size_t *buf_length)
Given a DNS packet p, generate the corresponding UDP payload.
Definition: dnsparser.c:1259
void GNUNET_DNS_request_answer(struct GNUNET_DNS_RequestHandle *rh, uint16_t reply_length, const char *reply)
If a GNUNET_DNS_RequestHandler calls this function, the request is supposed to be answered with the d...
Definition: dns_api.c:296
void GNUNET_DNS_request_drop(struct GNUNET_DNS_RequestHandle *rh)
If a GNUNET_DNS_RequestHandler calls this function, the request is to be dropped and no response shou...
Definition: dns_api.c:265
@ GNUNET_NO
@ GNUNET_SYSERR
@ GNUNET_ERROR_TYPE_ERROR
#define GNUNET_free(ptr)
Wrapper around free.
void GNUNET_STATISTICS_update(struct GNUNET_STATISTICS_Handle *handle, const char *name, int64_t delta, int make_persistent)
Set statistic value for the peer.
#define _(String)
GNU gettext support macro.
Definition: platform.h:177
struct GNUNET_DNS_RequestHandle * rh
Handle to submit the final result.
struct GNUNET_DNSPARSER_Packet * dns
DNS packet that is being modified.

References _, buf, ReplyContext::dns, gettext_noop, GNUNET_DNS_request_answer(), GNUNET_DNS_request_drop(), GNUNET_DNSPARSER_free_packet(), GNUNET_DNSPARSER_pack(), GNUNET_ERROR_TYPE_ERROR, GNUNET_free, GNUNET_log, GNUNET_NO, GNUNET_STATISTICS_update(), GNUNET_SYSERR, MAX_DNS_SIZE, ReplyContext::rh, and stats.

Referenced by submit_request().

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◆ submit_request()

static void submit_request ( struct ReplyContext rc)
static

Process the next record of the given request context.

When done, submit the reply and free the resources of the rc.

Parameters
rccontext to process

Definition at line 555 of file gnunet-daemon-pt.c.

556 {
557  struct GNUNET_DNSPARSER_Record *ra;
558  unsigned int ra_len;
559  unsigned int i;
560 
561  while (1)
562  {
563  switch (rc->group)
564  {
565  case ANSWERS:
566  ra = rc->dns->answers;
567  ra_len = rc->dns->num_answers;
568  break;
569 
570  case AUTHORITY_RECORDS:
571  ra = rc->dns->authority_records;
572  ra_len = rc->dns->num_authority_records;
573  break;
574 
575  case ADDITIONAL_RECORDS:
576  ra = rc->dns->additional_records;
577  ra_len = rc->dns->num_additional_records;
578  break;
579 
580  case END:
581  finish_request (rc);
582  return;
583 
584  default:
585  GNUNET_assert (0);
586  }
587  for (i = rc->offset; i < ra_len; i++)
588  {
589  switch (ra[i].type)
590  {
592  if (ipv4_pt)
593  {
594  rc->offset = i + 1;
595  modify_address (rc,
596  &ra[i]);
597  return;
598  }
599  break;
600 
602  if (ipv6_pt)
603  {
604  rc->offset = i + 1;
605  modify_address (rc,
606  &ra[i]);
607  return;
608  }
609  break;
610  }
611  }
612  rc->group++;
613  }
614 }
static int ipv4_pt
Are we doing IPv4-pt?
static int ipv6_pt
Are we doing IPv6-pt?
static void modify_address(struct ReplyContext *rc, struct GNUNET_DNSPARSER_Record *rec)
Modify the given DNS record by asking VPN to create a channel to the given address.
static void finish_request(struct ReplyContext *rc)
We're done modifying all records in the response.
#define GNUNET_DNSPARSER_TYPE_A
#define GNUNET_DNSPARSER_TYPE_AAAA
unsigned int num_answers
Number of answers in the packet, should be 0 for queries.
struct GNUNET_DNSPARSER_Record * answers
Array of all answers in the packet, must contain "num_answers" entries.
unsigned int num_additional_records
Number of additional records in the packet, should be 0 for queries.
struct GNUNET_DNSPARSER_Record * additional_records
Array of all additional answers in the packet, must contain "num_additional_records" entries.
struct GNUNET_DNSPARSER_Record * authority_records
Array of all authority records in the packet, must contain "num_authority_records" entries.
unsigned int num_authority_records
Number of authoritative answers in the packet, should be 0 for queries.
A DNS response record.
unsigned int offset
Offset in the current record group that is being modified.
enum RequestGroup group
Group that is being modified.
enum GNUNET_TESTBED_UnderlayLinkModelType type
the type of this model

References GNUNET_DNSPARSER_Packet::additional_records, ADDITIONAL_RECORDS, GNUNET_DNSPARSER_Packet::answers, ANSWERS, GNUNET_DNSPARSER_Packet::authority_records, AUTHORITY_RECORDS, ReplyContext::dns, END, finish_request(), GNUNET_assert, GNUNET_DNSPARSER_TYPE_A, GNUNET_DNSPARSER_TYPE_AAAA, ReplyContext::group, ipv4_pt, ipv6_pt, modify_address(), GNUNET_DNSPARSER_Packet::num_additional_records, GNUNET_DNSPARSER_Packet::num_answers, GNUNET_DNSPARSER_Packet::num_authority_records, ReplyContext::offset, and type.

Referenced by dns_post_request_handler(), and vpn_allocation_callback().

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◆ vpn_allocation_callback()

static void vpn_allocation_callback ( void *  cls,
int  af,
const void *  address 
)
static

Callback invoked from the VPN service once a redirection is available.

Provides the IP address that can now be used to reach the requested destination. We substitute the active record and then continue with 'submit_request' to look at the other records.

Parameters
clsour struct ReplyContext
afaddress family, AF_INET or AF_INET6; AF_UNSPEC on error; will match 'result_af' from the request
addressIP address (struct in_addr or struct in_addr6, depending on 'af') that the VPN allocated for the redirection; traffic to this IP will now be redirected to the specified target peer; NULL on error

Definition at line 461 of file gnunet-daemon-pt.c.

464 {
465  struct ReplyContext *rc = cls;
466 
467  rc->rr = NULL;
468  if (af == AF_UNSPEC)
469  {
472  GNUNET_free (rc);
473  return;
474  }
476  gettext_noop ("# DNS records modified"),
477  1,
478  GNUNET_NO);
479  switch (rc->rec->type)
480  {
482  GNUNET_assert (AF_INET == af);
483  GNUNET_memcpy (rc->rec->data.raw.data,
484  address,
485  sizeof(struct in_addr));
486  break;
487 
489  GNUNET_assert (AF_INET6 == af);
490  GNUNET_memcpy (rc->rec->data.raw.data,
491  address,
492  sizeof(struct in6_addr));
493  break;
494 
495  default:
496  GNUNET_assert (0);
497  return;
498  }
499  rc->rec = NULL;
500  submit_request (rc);
501 }
static char * address
GNS address for this phone.
static void submit_request(struct ReplyContext *rc)
Process the next record of the given request context.
#define GNUNET_memcpy(dst, src, n)
Call memcpy() but check for n being 0 first.
void * data
Binary record data.
uint16_t type
See GNUNET_DNSPARSER_TYPE_*.
union GNUNET_DNSPARSER_Record::@24 data
Payload of the record (which one of these is valid depends on the 'type').
struct GNUNET_DNSPARSER_RawRecord raw
Raw data for all other types.
Information tracked per DNS reply that we are processing.
struct GNUNET_DNSPARSER_Record * rec
Record for which we have an active redirection request.
struct GNUNET_VPN_RedirectionRequest * rr
Active redirection request with the VPN.

References address, GNUNET_DNSPARSER_RawRecord::data, GNUNET_DNSPARSER_Record::data, ReplyContext::dns, gettext_noop, GNUNET_assert, GNUNET_DNS_request_drop(), GNUNET_DNSPARSER_free_packet(), GNUNET_DNSPARSER_TYPE_A, GNUNET_DNSPARSER_TYPE_AAAA, GNUNET_free, GNUNET_memcpy, GNUNET_NO, GNUNET_STATISTICS_update(), GNUNET_DNSPARSER_Record::raw, ReplyContext::rec, ReplyContext::rh, ReplyContext::rr, stats, submit_request(), and GNUNET_DNSPARSER_Record::type.

Referenced by modify_address().

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◆ modify_address()

static void modify_address ( struct ReplyContext rc,
struct GNUNET_DNSPARSER_Record rec 
)
static

Modify the given DNS record by asking VPN to create a channel to the given address.

When done, continue with submitting other records from the request context ('submit_request' is our continuation).

Parameters
rccontext to process
recrecord to modify

Definition at line 514 of file gnunet-daemon-pt.c.

516 {
517  int af;
518 
519  switch (rec->type)
520  {
522  af = AF_INET;
523  GNUNET_assert (rec->data.raw.data_len == sizeof(struct in_addr));
524  break;
525 
527  af = AF_INET6;
528  GNUNET_assert (rec->data.raw.data_len == sizeof(struct in6_addr));
529  break;
530 
531  default:
532  GNUNET_assert (0);
533  return;
534  }
535  rc->rec = rec;
537  af,
538  af,
539  rec->data.raw.data,
541  TIMEOUT),
543  rc);
544 }
static struct GNUNET_VPN_Handle * vpn_handle
The handle to the VPN.
#define TIMEOUT
After how long do we time out if we could not get an IP from VPN or CADET?
static void vpn_allocation_callback(void *cls, int af, const void *address)
Callback invoked from the VPN service once a redirection is available.
struct GNUNET_TIME_Absolute GNUNET_TIME_relative_to_absolute(struct GNUNET_TIME_Relative rel)
Convert relative time to an absolute time in the future.
Definition: time.c:316
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.
Definition: vpn_api.c:439
size_t data_len
Number of bytes in data.

References GNUNET_DNSPARSER_RawRecord::data, GNUNET_DNSPARSER_Record::data, GNUNET_DNSPARSER_RawRecord::data_len, GNUNET_assert, GNUNET_DNSPARSER_TYPE_A, GNUNET_DNSPARSER_TYPE_AAAA, GNUNET_TIME_relative_to_absolute(), GNUNET_VPN_redirect_to_ip(), GNUNET_DNSPARSER_Record::raw, ReplyContext::rec, ReplyContext::rr, TIMEOUT, GNUNET_DNSPARSER_Record::type, vpn_allocation_callback(), and vpn_handle.

Referenced by submit_request().

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◆ work_test()

static int work_test ( const struct GNUNET_DNSPARSER_Record ra,
unsigned int  ra_len 
)
static

Test if any of the given records need protocol-translation work.

Parameters
raarray of records
ra_lennumber of entries in ra
Returns
GNUNET_YES if any of the given records require protocol-translation

Definition at line 625 of file gnunet-daemon-pt.c.

627 {
628  unsigned int i;
629 
630  for (i = 0; i < ra_len; i++)
631  {
632  switch (ra[i].type)
633  {
635  if (ipv4_pt)
636  return GNUNET_YES;
637  break;
638 
640  if (ipv6_pt)
641  return GNUNET_YES;
642  break;
643  }
644  }
645  return GNUNET_NO;
646 }
@ GNUNET_YES

References GNUNET_DNSPARSER_TYPE_A, GNUNET_DNSPARSER_TYPE_AAAA, GNUNET_NO, GNUNET_YES, ipv4_pt, ipv6_pt, and type.

Referenced by dns_post_request_handler().

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◆ dns_post_request_handler()

static void dns_post_request_handler ( void *  cls,
struct GNUNET_DNS_RequestHandle rh,
size_t  request_length,
const char *  request 
)
static

This function is called AFTER we got an IP address for a DNS request.

Now, the PT daemon has the chance to substitute the IP address with one from the VPN range to channel requests destined for this IP address via VPN and CADET.

Parameters
clsclosure
rhrequest handle to user for reply
request_lengthnumber of bytes in request
requestudp payload of the DNS request

Definition at line 661 of file gnunet-daemon-pt.c.

665 {
666  struct GNUNET_DNSPARSER_Packet *dns;
667  struct ReplyContext *rc;
668  int work;
669 
671  gettext_noop ("# DNS replies intercepted"),
672  1, GNUNET_NO);
674  request_length);
675  if (NULL == dns)
676  {
678  _ ("Failed to parse DNS request. Dropping.\n"));
680  return;
681  }
682  work = GNUNET_NO;
683  work |= work_test (dns->answers,
684  dns->num_answers);
689  if (! work)
690  {
693  return;
694  }
695  rc = GNUNET_new (struct ReplyContext);
696  rc->rh = rh;
697  rc->dns = dns;
698  rc->offset = 0;
699  rc->group = ANSWERS;
700  submit_request (rc);
701 }
static void work(void *cls)
Function called to process work items.
static int work_test(const struct GNUNET_DNSPARSER_Record *ra, unsigned int ra_len)
Test if any of the given records need protocol-translation work.
static struct GNUNET_VPN_RedirectionRequest * request
Opaque redirection request handle.
Definition: gnunet-vpn.c:40
struct GNUNET_DNSPARSER_Packet * GNUNET_DNSPARSER_parse(const char *udp_payload, size_t udp_payload_length)
Parse a UDP payload of a DNS packet in to a nice struct for further processing and manipulation.
Definition: dnsparser.c:656
void GNUNET_DNS_request_forward(struct GNUNET_DNS_RequestHandle *rh)
If a GNUNET_DNS_RequestHandler calls this function, the request is given to other clients or the glob...
Definition: dns_api.c:237
#define GNUNET_new(type)
Allocate a struct or union of the given type.
Easy-to-process, parsed version of a DNS packet.

References _, GNUNET_DNSPARSER_Packet::additional_records, GNUNET_DNSPARSER_Packet::answers, ANSWERS, GNUNET_DNSPARSER_Packet::authority_records, ReplyContext::dns, gettext_noop, GNUNET_DNS_request_drop(), GNUNET_DNS_request_forward(), GNUNET_DNSPARSER_free_packet(), GNUNET_DNSPARSER_parse(), GNUNET_ERROR_TYPE_ERROR, GNUNET_log, GNUNET_new, GNUNET_NO, GNUNET_STATISTICS_update(), ReplyContext::group, GNUNET_DNSPARSER_Packet::num_additional_records, GNUNET_DNSPARSER_Packet::num_answers, GNUNET_DNSPARSER_Packet::num_authority_records, ReplyContext::offset, request, ReplyContext::rh, stats, submit_request(), work(), and work_test().

Referenced by run().

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◆ timeout_request()

static void timeout_request ( void *  cls)
static

Task run if the time to answer a DNS request via CADET is over.

Parameters
clsthe struct RequestContext to abort

Definition at line 710 of file gnunet-daemon-pt.c.

711 {
712  struct RequestContext *rc = cls;
713  struct CadetExit *exit = rc->exit;
714 
716  gettext_noop ("# DNS requests dropped (timeout)"),
717  1,
718  GNUNET_NO);
720  GNUNET_free (rc);
721  if ((0 == get_channel_weight (exit)) &&
722  (NULL == exit->receive_queue_head))
723  {
724  /* this straw broke the camel's back: this channel now has
725  such a low score that it will not be used; close it! */
727  exit->cadet_channel = NULL;
729  exit_tail,
730  exit);
732  exit_tail,
733  exit);
734  /* go back to semi-innocent: mark as not great, but
735  avoid a prohibitively negative score (see
736  #get_channel_weight(), which checks for a certain
737  minimum number of transmissions before making
738  up an opinion) */exit->num_transmitted = 5;
739  exit->num_answered = 0;
741  /* now try to open an alternative exit */
742  try_open_exit ();
743  }
744 }
static void try_open_exit(void)
We are short on cadet exits, try to open another one.
void GNUNET_CADET_channel_destroy(struct GNUNET_CADET_Channel *channel)
Destroy an existing channel.
Definition: cadet_api.c:830
#define GNUNET_CONTAINER_DLL_insert_tail(head, tail, element)
Insert an element at the tail of a DLL.
struct RequestContext * receive_queue_head
Head of DLL of requests waiting for a response.
State we keep for a request that is going out via CADET.
struct CadetExit * exit
Exit that was chosen for this request.
struct GNUNET_DNS_RequestHandle * rh
Handle for interaction with DNS service.

References CadetExit::cadet_channel, dns_exit_available, RequestContext::exit, exit_head, exit_tail, get_channel_weight(), gettext_noop, GNUNET_CADET_channel_destroy(), GNUNET_CONTAINER_DLL_insert_tail, GNUNET_CONTAINER_DLL_remove, GNUNET_DNS_request_drop(), GNUNET_free, GNUNET_NO, GNUNET_STATISTICS_update(), CadetExit::num_answered, CadetExit::num_transmitted, CadetExit::receive_queue_head, RequestContext::rh, stats, and try_open_exit().

Referenced by dns_pre_request_handler().

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◆ dns_pre_request_handler()

static void dns_pre_request_handler ( void *  cls,
struct GNUNET_DNS_RequestHandle rh,
size_t  request_length,
const char *  request 
)
static

This function is called before the DNS request has been given to a "local" DNS resolver.

Channeling for DNS requests was enabled, so we now need to send the request via some CADET channel to a DNS EXIT for resolution.

Parameters
clsclosure
rhrequest handle to user for reply
request_lengthnumber of bytes in request
requestudp payload of the DNS request

Definition at line 759 of file gnunet-daemon-pt.c.

763 {
764  struct RequestContext *rc;
765  struct GNUNET_MQ_Envelope *env;
766  struct GNUNET_MessageHeader *hdr;
767  struct GNUNET_TUN_DnsHeader dns;
768  struct CadetExit *exit;
769 
771  gettext_noop ("# DNS requests intercepted"),
772  1, GNUNET_NO);
773  if (0 == dns_exit_available)
774  {
776  gettext_noop (
777  "# DNS requests dropped (DNS cadet channel down)"),
778  1, GNUNET_NO);
780  return;
781  }
782  if (request_length < sizeof(dns))
783  {
785  gettext_noop (
786  "# DNS requests dropped (malformed)"),
787  1, GNUNET_NO);
789  return;
790  }
791  exit = choose_exit ();
792  GNUNET_assert (NULL != exit);
793  GNUNET_assert (NULL != exit->cadet_channel);
794 
795  env = GNUNET_MQ_msg_extra (hdr,
796  request_length,
798  GNUNET_memcpy (&hdr[1],
799  request,
800  request_length);
801  rc = GNUNET_new (struct RequestContext);
802  rc->exit = exit;
803  rc->rh = rh;
806  rc);
807  GNUNET_memcpy (&dns,
808  request,
809  sizeof(dns));
810  rc->dns_id = dns.id;
811  rc->env = env;
813  exit->receive_queue_tail,
814  rc);
815  if (0 < exit->idle)
816  exit->idle--;
817  exit->num_transmitted++;
820 }
struct GNUNET_MQ_Envelope * env
Definition: 005.c:1
static void timeout_request(void *cls)
Task run if the time to answer a DNS request via CADET is over.
static struct CadetExit * choose_exit()
Choose a cadet exit for a DNS request.
struct GNUNET_MQ_Handle * GNUNET_CADET_get_mq(const struct GNUNET_CADET_Channel *channel)
Obtain the message queue for a connected peer.
Definition: cadet_api.c:1066
void GNUNET_MQ_send(struct GNUNET_MQ_Handle *mq, struct GNUNET_MQ_Envelope *ev)
Send a message with the given message queue.
Definition: mq.c:304
#define GNUNET_MQ_msg_extra(mvar, esize, type)
Allocate an envelope, with extra space allocated after the space needed by the message struct.
Definition: gnunet_mq_lib.h:62
struct GNUNET_MQ_Envelope * GNUNET_MQ_env_copy(struct GNUNET_MQ_Envelope *env)
Function to copy an envelope.
Definition: mq.c:359
#define GNUNET_MESSAGE_TYPE_VPN_DNS_TO_INTERNET
Type of messages containing an DNS request for a DNS exit service.
struct GNUNET_SCHEDULER_Task * GNUNET_SCHEDULER_add_delayed(struct GNUNET_TIME_Relative delay, GNUNET_SCHEDULER_TaskCallback task, void *task_cls)
Schedule a new task to be run with a specified delay.
Definition: scheduler.c:1241
struct RequestContext * receive_queue_tail
Tail of DLL of requests waiting for a response.
Header for all communications.
struct GNUNET_SCHEDULER_Task * timeout_task
Task used to abort this operation with timeout.
struct GNUNET_MQ_Envelope * env
Envelope with the request we are transmitting.
uint16_t dns_id
ID of the original DNS request (used to match the reply).

References CadetExit::cadet_channel, choose_exit(), dns_exit_available, RequestContext::dns_id, env, RequestContext::env, RequestContext::exit, gettext_noop, GNUNET_assert, GNUNET_CADET_get_mq(), GNUNET_CONTAINER_DLL_remove, GNUNET_DNS_request_drop(), GNUNET_memcpy, GNUNET_MESSAGE_TYPE_VPN_DNS_TO_INTERNET, GNUNET_MQ_env_copy(), GNUNET_MQ_msg_extra, GNUNET_MQ_send(), GNUNET_new, GNUNET_NO, GNUNET_SCHEDULER_add_delayed(), GNUNET_STATISTICS_update(), GNUNET_TUN_DnsHeader::id, CadetExit::idle, CadetExit::num_transmitted, CadetExit::receive_queue_head, CadetExit::receive_queue_tail, request, RequestContext::rh, stats, TIMEOUT, timeout_request(), and RequestContext::timeout_task.

Referenced by run().

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◆ check_dns_response()

static GNUNET_NETWORK_STRUCT_END int check_dns_response ( void *  cls,
const struct DnsResponseMessage msg 
)
static

Process a request via cadet to perform a DNS query.

Parameters
clsthe struct CadetExit which got the message
msgthe actual message
Returns
GNUNET_OK to keep the connection open, GNUNET_SYSERR to close it (signal serious error)

Definition at line 854 of file gnunet-daemon-pt.c.

856 {
857  return GNUNET_OK; /* all OK */
858 }
@ GNUNET_OK

References GNUNET_OK.

◆ handle_dns_response()

static void handle_dns_response ( void *  cls,
const struct DnsResponseMessage msg 
)
static

Process a request via cadet to perform a DNS query.

Parameters
clsthe struct CadetExit which got the message
msgthe actual message

Definition at line 868 of file gnunet-daemon-pt.c.

870 {
871  struct CadetExit *exit = cls;
872  size_t mlen;
873  struct RequestContext *rc;
874 
875  mlen = ntohs (msg->header.size) - sizeof(*msg);
876  for (rc = exit->receive_queue_head; NULL != rc; rc = rc->next)
877  {
878  if (msg->dns.id == rc->dns_id)
879  {
881  gettext_noop ("# DNS replies received"),
882  1,
883  GNUNET_NO);
885  mlen + sizeof(struct GNUNET_TUN_DnsHeader),
886  (const void *) &msg->dns);
889  rc);
891  GNUNET_MQ_discard (rc->env);
892  GNUNET_free (rc);
893  exit->num_answered++;
894  return;
895  }
896  }
898  gettext_noop ("# DNS replies dropped (too late?)"),
899  1, GNUNET_NO);
900 }
struct GNUNET_MessageHeader * msg
Definition: 005.c:2
void GNUNET_MQ_discard(struct GNUNET_MQ_Envelope *mqm)
Discard the message queue message, free all allocated resources.
Definition: mq.c:285
void * GNUNET_SCHEDULER_cancel(struct GNUNET_SCHEDULER_Task *task)
Cancel the task with the specified identifier.
Definition: scheduler.c:944
uint16_t size
The length of the struct (in bytes, including the length field itself), in big-endian format.
struct RequestContext * next
We keep these in a DLL.
uint16_t mlen
Length of the request message that follows this struct.

References RequestContext::dns_id, RequestContext::env, RequestContext::exit, gettext_noop, GNUNET_CONTAINER_DLL_remove, GNUNET_DNS_request_answer(), GNUNET_free, GNUNET_MQ_discard(), GNUNET_NO, GNUNET_SCHEDULER_cancel(), GNUNET_STATISTICS_update(), RequestContext::mlen, msg, RequestContext::next, CadetExit::num_answered, CadetExit::receive_queue_head, CadetExit::receive_queue_tail, RequestContext::rh, GNUNET_MessageHeader::size, stats, and RequestContext::timeout_task.

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◆ abort_all_requests()

static void abort_all_requests ( struct CadetExit exit)
static

Abort all pending DNS requests with the given cadet exit.

Parameters
exitcadet exit to abort requests for

Definition at line 909 of file gnunet-daemon-pt.c.

910 {
911  struct RequestContext *rc;
912 
913  while (NULL != (rc = exit->receive_queue_head))
914  {
917  rc);
920  GNUNET_MQ_discard (rc->env);
921  GNUNET_free (rc);
922  }
923 }

References RequestContext::env, RequestContext::exit, GNUNET_CONTAINER_DLL_remove, GNUNET_DNS_request_drop(), GNUNET_free, GNUNET_MQ_discard(), GNUNET_SCHEDULER_cancel(), CadetExit::receive_queue_head, CadetExit::receive_queue_tail, RequestContext::rh, and RequestContext::timeout_task.

Referenced by cleanup().

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◆ cleanup()

static void cleanup ( void *  cls)
static

Function scheduled as very last function, cleans up after us.

Parameters
clsclosure, NULL

Definition at line 932 of file gnunet-daemon-pt.c.

933 {
934  struct CadetExit *exit;
935 
937  "Protocol translation daemon is shutting down now\n");
938  if (NULL != vpn_handle)
939  {
941  vpn_handle = NULL;
942  }
943  while (NULL != (exit = exit_head))
944  {
946  exit_tail,
947  exit);
948  if (NULL != exit->cadet_channel)
949  {
951  exit->cadet_channel = NULL;
952  }
953  abort_all_requests (exit);
954  GNUNET_free (exit);
955  }
956  if (NULL != cadet_handle)
957  {
959  cadet_handle = NULL;
960  }
961  if (NULL != dns_post_handle)
962  {
964  dns_post_handle = NULL;
965  }
966  if (NULL != dns_pre_handle)
967  {
969  dns_pre_handle = NULL;
970  }
971  if (NULL != stats)
972  {
974  stats = NULL;
975  }
976  if (NULL != dht_get)
977  {
979  dht_get = NULL;
980  }
981  if (NULL != dht)
982  {
984  dht = NULL;
985  }
986 }
static struct GNUNET_DNS_Handle * dns_pre_handle
The handle to DNS pre-resolution modifications.
static struct GNUNET_DHT_Handle * dht
Handle to access the DHT.
static struct GNUNET_DNS_Handle * dns_post_handle
The handle to DNS post-resolution modifications.
static void abort_all_requests(struct CadetExit *exit)
Abort all pending DNS requests with the given cadet exit.
static struct GNUNET_DHT_GetHandle * dht_get
Our DHT GET operation to find DNS exits.
void GNUNET_CADET_disconnect(struct GNUNET_CADET_Handle *handle)
Disconnect from the cadet service.
Definition: cadet_api.c:774
void GNUNET_DHT_get_stop(struct GNUNET_DHT_GetHandle *get_handle)
Stop async DHT-get.
Definition: dht_api.c:1237
void GNUNET_DHT_disconnect(struct GNUNET_DHT_Handle *handle)
Shutdown connection with the DHT service.
Definition: dht_api.c:1062
void GNUNET_DNS_disconnect(struct GNUNET_DNS_Handle *dh)
Disconnect from the DNS service.
Definition: dns_api.c:363
@ GNUNET_ERROR_TYPE_DEBUG
void GNUNET_STATISTICS_destroy(struct GNUNET_STATISTICS_Handle *h, int sync_first)
Destroy a handle (free all state associated with it).
void GNUNET_VPN_disconnect(struct GNUNET_VPN_Handle *vh)
Disconnect from the VPN service.
Definition: vpn_api.c:512

References abort_all_requests(), CadetExit::cadet_channel, cadet_handle, dht, dht_get, dns_post_handle, dns_pre_handle, exit_head, exit_tail, GNUNET_CADET_channel_destroy(), GNUNET_CADET_disconnect(), GNUNET_CONTAINER_DLL_remove, GNUNET_DHT_disconnect(), GNUNET_DHT_get_stop(), GNUNET_DNS_disconnect(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_free, GNUNET_log, GNUNET_STATISTICS_destroy(), GNUNET_VPN_disconnect(), GNUNET_YES, stats, and vpn_handle.

Referenced by run().

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◆ cadet_channel_end_cb()

static void cadet_channel_end_cb ( void *  cls,
const struct GNUNET_CADET_Channel channel 
)
static

Function called whenever a channel is destroyed.

Should clean up the associated state and attempt to build a new one.

It must NOT call GNUNET_CADET_channel_destroy on the channel.

Parameters
clsclosure (the struct CadetExit set from GNUNET_CADET_connect)
channelconnection to the other end (henceforth invalid)
channel_ctxplace where local state associated with the channel is stored

Definition at line 1001 of file gnunet-daemon-pt.c.

1003 {
1004  struct CadetExit *exit = cls;
1005  struct CadetExit *alt;
1006  struct RequestContext *rc;
1007 
1008  exit->cadet_channel = NULL;
1010  /* open alternative channels */
1011  /* our channel is now closed, move our requests to an alternative
1012  channel */
1013  alt = choose_exit ();
1014  while (NULL != (rc = exit->receive_queue_head))
1015  {
1018  rc);
1019  rc->exit = alt;
1021  alt->receive_queue_tail,
1022  rc);
1024  GNUNET_MQ_env_copy (rc->env));
1025  }
1026  try_open_exit ();
1027 }

References CadetExit::cadet_channel, choose_exit(), dns_exit_available, RequestContext::env, RequestContext::exit, GNUNET_CADET_get_mq(), GNUNET_CONTAINER_DLL_insert, GNUNET_CONTAINER_DLL_remove, GNUNET_MQ_env_copy(), GNUNET_MQ_send(), CadetExit::receive_queue_head, CadetExit::receive_queue_tail, and try_open_exit().

Referenced by try_open_exit().

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◆ channel_idle_notify_cb()

static void channel_idle_notify_cb ( void *  cls,
const struct GNUNET_CADET_Channel channel,
int  window_size 
)
static

Function called whenever a channel has excess capacity.

Parameters
clsthe struct CadetExit
channelconnection to the other end
window_sizehow much capacity do we have

Definition at line 1038 of file gnunet-daemon-pt.c.

1041 {
1042  struct CadetExit *pos = cls;
1043 
1044  pos->idle = window_size;
1045 }

References CadetExit::idle.

Referenced by try_open_exit().

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◆ handle_dht_result()

static void handle_dht_result ( void *  cls,
struct GNUNET_TIME_Absolute  exp,
const struct GNUNET_HashCode key,
const struct GNUNET_PeerIdentity trunc_peer,
const struct GNUNET_DHT_PathElement get_path,
unsigned int  get_path_length,
const struct GNUNET_DHT_PathElement put_path,
unsigned int  put_path_length,
enum GNUNET_BLOCK_Type  type,
size_t  size,
const void *  data 
)
static

Function called whenever we find an advertisement for a DNS exit in the DHT.

If we don't have a cadet channel, we should build one; otherwise, we should save the advertisement for later use.

Parameters
clsclosure
expwhen will this value expire
keykey of the result
trunc_peerpeer that was truncated (or NULL if not truncated)
get_pathpeers on reply path (or NULL if not recorded) [0] = datastore's first neighbor, [length - 1] = local peer
get_path_lengthnumber of entries in get_path
put_pathpeers on the PUT path (or NULL if not recorded) [0] = origin, [length - 1] = datastore
put_path_lengthnumber of entries in put_path
typetype of the result
sizenumber of bytes in data
datapointer to the result data

Definition at line 1139 of file gnunet-daemon-pt.c.

1149 {
1150  const struct GNUNET_DNS_Advertisement *ad;
1151  struct CadetExit *exit;
1152 
1153  if (sizeof(struct GNUNET_DNS_Advertisement) != size)
1154  {
1155  GNUNET_break (0);
1156  return;
1157  }
1158  ad = data;
1159  for (exit = exit_head; NULL != exit; exit = exit->next)
1160  if (0 == GNUNET_memcmp (&ad->peer,
1161  &exit->peer))
1162  break;
1163  if (NULL == exit)
1164  {
1165  exit = GNUNET_new (struct CadetExit);
1166  exit->peer = ad->peer;
1167  /* channel is closed, so insert at the end */
1169  exit_tail,
1170  exit);
1171  }
1174  ad->expiration_time));
1176  try_open_exit ();
1177 }
#define MAX_OPEN_TUNNELS
How many channels do we open at most at the same time?
uint32_t data
The data value.
#define GNUNET_memcmp(a, b)
Compare memory in a and b, where both must be of the same pointer type.
struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_max(struct GNUNET_TIME_Absolute t1, struct GNUNET_TIME_Absolute t2)
Return the maximum of two absolute time values.
Definition: time.c:367
struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_ntoh(struct GNUNET_TIME_AbsoluteNBO a)
Convert absolute time from network byte order.
Definition: time.c:737
static unsigned int size
Size of the "table".
Definition: peer.c:68
struct GNUNET_TIME_Absolute expiration
At what time did the peer's advertisement expire?
This is the structure describing an DNS exit service.
Definition: block_dns.h:45
struct GNUNET_PeerIdentity peer
The peer providing this service.
Definition: block_dns.h:65
struct GNUNET_TIME_AbsoluteNBO expiration_time
When does this signature expire?
Definition: block_dns.h:60

References data, dns_exit_available, exit_head, exit_tail, CadetExit::expiration, GNUNET_DNS_Advertisement::expiration_time, GNUNET_break, GNUNET_CONTAINER_DLL_insert_tail, GNUNET_memcmp, GNUNET_new, GNUNET_TIME_absolute_max(), GNUNET_TIME_absolute_ntoh(), MAX_OPEN_TUNNELS, CadetExit::next, GNUNET_DNS_Advertisement::peer, CadetExit::peer, size, and try_open_exit().

Referenced by run().

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◆ run()

static void run ( void *  cls,
char *const *  args,
const char *  cfgfile,
const struct GNUNET_CONFIGURATION_Handle cfg_ 
)
static

Main function that will be run by the scheduler.

Parameters
clsclosure
argsremaining command-line arguments
cfgfilename of the configuration file used (for saving, can be NULL!)
cfg_configuration

Definition at line 1189 of file gnunet-daemon-pt.c.

1192 {
1193  struct GNUNET_HashCode dns_key;
1194 
1195  cfg = cfg_;
1197  cfg);
1199  "pt",
1200  "TUNNEL_IPV4");
1202  "pt",
1203  "TUNNEL_IPV6");
1205  "pt",
1206  "TUNNEL_DNS");
1207  if (! (ipv4_pt || ipv6_pt || dns_channel))
1208  {
1210  _ ("No useful service enabled. Exiting.\n"));
1212  return;
1213  }
1215  if (ipv4_pt || ipv6_pt)
1216  {
1221  NULL);
1222  if (NULL == dns_post_handle)
1223  {
1225  _ ("Failed to connect to %s service. Exiting.\n"),
1226  "DNS");
1228  return;
1229  }
1231  if (NULL == vpn_handle)
1232  {
1234  _ ("Failed to connect to %s service. Exiting.\n"),
1235  "VPN");
1237  return;
1238  }
1239  }
1240  if (dns_channel)
1241  {
1246  NULL);
1247  if (NULL == dns_pre_handle)
1248  {
1250  _ ("Failed to connect to %s service. Exiting.\n"),
1251  "DNS");
1253  return;
1254  }
1256  if (NULL == cadet_handle)
1257  {
1259  _ ("Failed to connect to %s service. Exiting.\n"),
1260  "CADET");
1262  return;
1263  }
1264  dht = GNUNET_DHT_connect (cfg, 1);
1265  if (NULL == dht)
1266  {
1268  _ ("Failed to connect to %s service. Exiting.\n"),
1269  "DHT");
1271  return;
1272  }
1273  GNUNET_CRYPTO_hash ("dns",
1274  strlen ("dns"),
1275  &dns_key);
1278  &dns_key,
1279  1,
1281  NULL, 0,
1283  NULL);
1284  }
1285 }
@ GNUNET_BLOCK_TYPE_DNS
Block for storing DNS exit service advertisements.
static void dns_pre_request_handler(void *cls, struct GNUNET_DNS_RequestHandle *rh, size_t request_length, const char *request)
This function is called before the DNS request has been given to a "local" DNS resolver.
static int dns_channel
Are we channeling DNS queries?
static const struct GNUNET_CONFIGURATION_Handle * cfg
The handle to the configuration used throughout the process.
static void cleanup(void *cls)
Function scheduled as very last function, cleans up after us.
static void handle_dht_result(void *cls, struct GNUNET_TIME_Absolute exp, const struct GNUNET_HashCode *key, const struct GNUNET_PeerIdentity *trunc_peer, const struct GNUNET_DHT_PathElement *get_path, unsigned int get_path_length, const struct GNUNET_DHT_PathElement *put_path, unsigned int put_path_length, enum GNUNET_BLOCK_Type type, size_t size, const void *data)
Function called whenever we find an advertisement for a DNS exit in the DHT.
static void dns_post_request_handler(void *cls, struct GNUNET_DNS_RequestHandle *rh, size_t request_length, const char *request)
This function is called AFTER we got an IP address for a DNS request.
struct GNUNET_CADET_Handle * GNUNET_CADET_connect(const struct GNUNET_CONFIGURATION_Handle *cfg)
Connect to the MQ-based cadet service.
Definition: cadet_api.c:894
enum GNUNET_GenericReturnValue GNUNET_CONFIGURATION_get_value_yesno(const struct GNUNET_CONFIGURATION_Handle *cfg, const char *section, const char *option)
Get a configuration value that should be in a set of "YES" or "NO".
struct GNUNET_DHT_Handle * GNUNET_DHT_connect(const struct GNUNET_CONFIGURATION_Handle *cfg, unsigned int ht_len)
Initialize the connection with the DHT service.
Definition: dht_api.c:1039
struct GNUNET_DHT_GetHandle * GNUNET_DHT_get_start(struct GNUNET_DHT_Handle *handle, enum GNUNET_BLOCK_Type type, const struct GNUNET_HashCode *key, uint32_t desired_replication_level, enum GNUNET_DHT_RouteOption options, const void *xquery, size_t xquery_size, GNUNET_DHT_GetIterator iter, void *iter_cls)
Perform an asynchronous GET operation on the DHT identified.
Definition: dht_api.c:1164
@ GNUNET_DHT_RO_DEMULTIPLEX_EVERYWHERE
Each peer along the way should process the request (otherwise only peers locally closest to the key w...
struct GNUNET_DNS_Handle * GNUNET_DNS_connect(const struct GNUNET_CONFIGURATION_Handle *cfg, enum GNUNET_DNS_Flags flags, GNUNET_DNS_RequestHandler rh, void *rh_cls)
Connect to the service-dns.
Definition: dns_api.c:340
@ GNUNET_DNS_FLAG_PRE_RESOLUTION
This client should be called on requests that have not yet been resolved as this client provides a re...
@ GNUNET_DNS_FLAG_POST_RESOLUTION
This client wants to be called on the results of a DNS resolution (either resolved by PRE-RESOLUTION ...
void GNUNET_SCHEDULER_shutdown(void)
Request the shutdown of a scheduler.
Definition: scheduler.c:534
struct GNUNET_SCHEDULER_Task * GNUNET_SCHEDULER_add_shutdown(GNUNET_SCHEDULER_TaskCallback task, void *task_cls)
Schedule a new task to be run on shutdown, that is when a CTRL-C signal is received,...
Definition: scheduler.c:1303
struct GNUNET_STATISTICS_Handle * GNUNET_STATISTICS_create(const char *subsystem, const struct GNUNET_CONFIGURATION_Handle *cfg)
Get handle for the statistics service.
struct GNUNET_VPN_Handle * GNUNET_VPN_connect(const struct GNUNET_CONFIGURATION_Handle *cfg)
Connect to the VPN service.
Definition: vpn_api.c:490

References _, cadet_handle, cfg, cleanup(), dht, dht_get, dns_channel, dns_post_handle, dns_post_request_handler(), dns_pre_handle, dns_pre_request_handler(), GNUNET_BLOCK_TYPE_DNS, GNUNET_CADET_connect(), GNUNET_CONFIGURATION_get_value_yesno(), GNUNET_CRYPTO_hash(), GNUNET_DHT_connect(), GNUNET_DHT_get_start(), GNUNET_DHT_RO_DEMULTIPLEX_EVERYWHERE, GNUNET_DNS_connect(), GNUNET_DNS_FLAG_POST_RESOLUTION, GNUNET_DNS_FLAG_PRE_RESOLUTION, GNUNET_ERROR_TYPE_ERROR, GNUNET_log, GNUNET_SCHEDULER_add_shutdown(), GNUNET_SCHEDULER_shutdown(), GNUNET_STATISTICS_create(), GNUNET_VPN_connect(), handle_dht_result(), ipv4_pt, ipv6_pt, stats, and vpn_handle.

Referenced by main().

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◆ main()

int main ( int  argc,
char *const *  argv 
)

The main function.

Parameters
argcnumber of arguments from the command line
argvcommand line arguments
Returns
0 ok, 1 on error

Definition at line 1296 of file gnunet-daemon-pt.c.

1298 {
1299  static const struct GNUNET_GETOPT_CommandLineOption options[] = {
1301  };
1302  int ret;
1303 
1305  argv,
1306  &argc,
1307  &argv))
1308  return 2;
1309  ret = (GNUNET_OK ==
1310  GNUNET_PROGRAM_run (argc,
1311  argv,
1312  "gnunet-daemon-pt",
1313  gettext_noop (
1314  "Daemon to run to perform IP protocol translation to GNUnet"),
1315  options,
1316  &run,
1317  NULL))
1318  ? 0
1319  : 1;
1320  GNUNET_free_nz ((void *) argv);
1321  return ret;
1322 }
struct GNUNET_GETOPT_CommandLineOption GNUNET_GETOPT_OPTION_END
Definition: 002.c:13
struct GNUNET_GETOPT_CommandLineOption options[]
Definition: 002.c:5
static int ret
Return value of the commandline.
Definition: gnunet-abd.c:81
static void run(void *cls, char *const *args, const char *cfgfile, const struct GNUNET_CONFIGURATION_Handle *cfg_)
Main function that will be run by the scheduler.
#define GNUNET_free_nz(ptr)
Wrapper around free.
enum GNUNET_GenericReturnValue GNUNET_PROGRAM_run(int argc, char *const *argv, const char *binaryName, const char *binaryHelp, const struct GNUNET_GETOPT_CommandLineOption *options, GNUNET_PROGRAM_Main task, void *task_cls)
Run a standard GNUnet command startup sequence (initialize loggers and configuration,...
Definition: program.c:400
enum GNUNET_GenericReturnValue GNUNET_STRINGS_get_utf8_args(int argc, char *const *argv, int *u8argc, char *const **u8argv)
Returns utf-8 encoded arguments.
Definition: strings.c:1222
Definition of a command line option.

References gettext_noop, GNUNET_free_nz, GNUNET_GETOPT_OPTION_END, GNUNET_OK, GNUNET_PROGRAM_run(), GNUNET_STRINGS_get_utf8_args(), options, ret, and run().

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Variable Documentation

◆ exit_head

struct CadetExit* exit_head
static

Head of DLL of cadet exits.

Cadet exits with an open channel are always at the beginning (so we do not have to traverse the entire list to find them).

Definition at line 232 of file gnunet-daemon-pt.c.

Referenced by choose_exit(), cleanup(), handle_dht_result(), timeout_request(), and try_open_exit().

◆ exit_tail

struct CadetExit* exit_tail
static

Tail of DLL of cadet exits.

Definition at line 237 of file gnunet-daemon-pt.c.

Referenced by cleanup(), handle_dht_result(), timeout_request(), and try_open_exit().

◆ cfg

const struct GNUNET_CONFIGURATION_Handle* cfg
static

The handle to the configuration used throughout the process.

Definition at line 242 of file gnunet-daemon-pt.c.

Referenced by run().

◆ vpn_handle

struct GNUNET_VPN_Handle* vpn_handle
static

The handle to the VPN.

Definition at line 247 of file gnunet-daemon-pt.c.

Referenced by cleanup(), modify_address(), and run().

◆ cadet_handle

struct GNUNET_CADET_Handle* cadet_handle
static

The handle to the CADET service.

Definition at line 252 of file gnunet-daemon-pt.c.

Referenced by cleanup(), run(), and try_open_exit().

◆ stats

◆ dns_post_handle

struct GNUNET_DNS_Handle* dns_post_handle
static

The handle to DNS post-resolution modifications.

Definition at line 262 of file gnunet-daemon-pt.c.

Referenced by cleanup(), and run().

◆ dns_pre_handle

struct GNUNET_DNS_Handle* dns_pre_handle
static

The handle to DNS pre-resolution modifications.

Definition at line 267 of file gnunet-daemon-pt.c.

Referenced by cleanup(), and run().

◆ dht

struct GNUNET_DHT_Handle* dht
static

Handle to access the DHT.

Definition at line 272 of file gnunet-daemon-pt.c.

Referenced by cleanup(), and run().

◆ dht_get

struct GNUNET_DHT_GetHandle* dht_get
static

Our DHT GET operation to find DNS exits.

Definition at line 277 of file gnunet-daemon-pt.c.

Referenced by cleanup(), and run().

◆ ipv4_pt

int ipv4_pt
static

Are we doing IPv4-pt?

Definition at line 282 of file gnunet-daemon-pt.c.

Referenced by run(), submit_request(), and work_test().

◆ ipv6_pt

int ipv6_pt
static

Are we doing IPv6-pt?

Definition at line 287 of file gnunet-daemon-pt.c.

Referenced by run(), submit_request(), and work_test().

◆ dns_channel

int dns_channel
static

Are we channeling DNS queries?

Definition at line 292 of file gnunet-daemon-pt.c.

Referenced by run().

◆ dns_exit_available

unsigned int dns_exit_available
static

Number of DNS exit peers we currently have in the cadet channel.

Used to see if using the cadet channel makes any sense right now, as well as to decide if we should open new channels.

Definition at line 299 of file gnunet-daemon-pt.c.

Referenced by cadet_channel_end_cb(), dns_pre_request_handler(), handle_dht_result(), timeout_request(), and try_open_exit().