GNUnet 0.22.2
gnunet-service-nat_helper.c File Reference

runs the gnunet-helper-nat-server More...

#include "platform.h"
#include "gnunet_util_lib.h"
#include "gnunet-service-nat_helper.h"
Include dependency graph for gnunet-service-nat_helper.c:

Go to the source code of this file.

Data Structures

struct  HelperContext
 Information we keep per NAT helper process. More...
 

Functions

static void restart_nat_server (void *cls)
 Task that restarts the gnunet-helper-nat-server process after a crash after a certain delay. More...
 
static void try_again (struct HelperContext *h)
 Try again starting the helper later. More...
 
static void nat_server_read (void *cls)
 We have been notified that gnunet-helper-nat-server has written something to stdout. More...
 
struct HelperContextGN_start_gnunet_nat_server_ (const struct in_addr *internal_address, GN_ReversalCallback cb, void *cb_cls, const struct GNUNET_CONFIGURATION_Handle *cfg)
 Start the gnunet-helper-nat-server and process incoming requests. More...
 
void GN_stop_gnunet_nat_server_ (struct HelperContext *h)
 Start the gnunet-helper-nat-server and process incoming requests. More...
 
int GN_request_connection_reversal (const struct in_addr *internal_address, uint16_t internal_port, const struct in_addr *remote_v4, const struct GNUNET_CONFIGURATION_Handle *cfg)
 We want to connect to a peer that is behind NAT. More...
 

Detailed Description

runs the gnunet-helper-nat-server

Author
Milan Bouchet-Valat
Christian Grothoff

Definition in file gnunet-service-nat_helper.c.

Function Documentation

◆ restart_nat_server()

static void restart_nat_server ( void *  cls)
static

Task that restarts the gnunet-helper-nat-server process after a crash after a certain delay.

Parameters
clsa struct HelperContext

Definition at line 205 of file gnunet-service-nat_helper.c.

206{
207 struct HelperContext *h = cls;
208 char *binary;
209 char ia[INET_ADDRSTRLEN];
210
211 h->server_read_task = NULL;
212 GNUNET_assert (NULL !=
213 inet_ntop (AF_INET, &h->internal_address, ia, sizeof(ia)));
214 /* Start the server process */
215 binary = GNUNET_OS_get_suid_binary_path (h->cfg, "gnunet-helper-nat-server");
217 {
218 /* move instantly to max delay, as this is unlikely to be fixed */
220 GNUNET_free (binary);
221 try_again (h);
222 return;
223 }
224 h->server_stdout =
226 if (NULL == h->server_stdout)
227 {
229 GNUNET_free (binary);
230 try_again (h);
231 return;
232 }
234 "Starting `%s' at `%s'\n",
235 "gnunet-helper-nat-server",
236 ia);
238 NULL,
239 h->server_stdout,
240 NULL,
241 binary,
242 "gnunet-helper-nat-server",
243 ia,
244 NULL);
245 GNUNET_free (binary);
246 if (NULL == h->server_proc)
247 {
249 _ ("Failed to start %s\n"),
250 "gnunet-helper-nat-server");
251 GNUNET_DISK_pipe_close (h->server_stdout);
252 h->server_stdout = NULL;
253 try_again (h);
254 return;
255 }
256 /* Close the write end of the read pipe */
258 h->server_stdout_handle =
260 h->server_read_task =
262 h->server_stdout_handle,
264 h);
265}
static struct GNUNET_ARM_Handle * h
Connection with ARM.
Definition: gnunet-arm.c:98
static void nat_server_read(void *cls)
We have been notified that gnunet-helper-nat-server has written something to stdout.
static void try_again(struct HelperContext *h)
Try again starting the helper later.
const struct GNUNET_DISK_FileHandle * GNUNET_DISK_pipe_handle(const struct GNUNET_DISK_PipeHandle *p, enum GNUNET_DISK_PipeEnd n)
Get the handle to a particular pipe end.
Definition: disk.c:1600
struct GNUNET_DISK_PipeHandle * GNUNET_DISK_pipe(enum GNUNET_DISK_PipeFlags pf)
Creates an interprocess channel.
Definition: disk.c:1423
enum GNUNET_GenericReturnValue GNUNET_DISK_pipe_close(struct GNUNET_DISK_PipeHandle *p)
Closes an interprocess channel.
Definition: disk.c:1570
enum GNUNET_GenericReturnValue GNUNET_DISK_pipe_close_end(struct GNUNET_DISK_PipeHandle *p, enum GNUNET_DISK_PipeEnd end)
Closes one half of an interprocess channel.
Definition: disk.c:1517
@ GNUNET_DISK_PF_BLOCKING_RW
Configure both pipe ends for blocking operations if set.
@ GNUNET_DISK_PIPE_END_WRITE
The writing-end of a pipe.
@ GNUNET_DISK_PIPE_END_READ
The reading-end of a pipe.
#define GNUNET_log(kind,...)
@ GNUNET_YES
#define GNUNET_assert(cond)
Use this for fatal errors that cannot be handled.
#define GNUNET_log_strerror(level, cmd)
Log an error message at log-level 'level' that indicates a failure of the command 'cmd' with the mess...
@ GNUNET_ERROR_TYPE_WARNING
@ GNUNET_ERROR_TYPE_ERROR
@ GNUNET_ERROR_TYPE_DEBUG
#define GNUNET_free(ptr)
Wrapper around free.
struct GNUNET_OS_Process * GNUNET_OS_start_process(enum GNUNET_OS_InheritStdioFlags std_inheritance, struct GNUNET_DISK_PipeHandle *pipe_stdin, struct GNUNET_DISK_PipeHandle *pipe_stdout, struct GNUNET_DISK_PipeHandle *pipe_stderr, const char *filename,...)
Start a process.
Definition: os_priority.c:620
char * GNUNET_OS_get_suid_binary_path(const struct GNUNET_CONFIGURATION_Handle *cfg, const char *progname)
Given the name of a helper, service or daemon binary construct the full path to the binary using the ...
enum GNUNET_GenericReturnValue GNUNET_OS_check_helper_binary(const char *binary, bool check_suid, const char *params)
Check whether an executable exists and possibly if the suid bit is set on the file.
@ GNUNET_OS_INHERIT_STD_NONE
No standard streams should be inherited.
Definition: gnunet_os_lib.h:77
struct GNUNET_SCHEDULER_Task * GNUNET_SCHEDULER_add_read_file(struct GNUNET_TIME_Relative delay, const struct GNUNET_DISK_FileHandle *rfd, GNUNET_SCHEDULER_TaskCallback task, void *task_cls)
Schedule a new task to be run with a specified delay or when the specified file descriptor is ready f...
Definition: scheduler.c:1660
#define GNUNET_TIME_UNIT_FOREVER_REL
Constant used to specify "forever".
#define GNUNET_TIME_STD_EXPONENTIAL_BACKOFF_THRESHOLD
Threshold after which exponential backoff should not increase (15 m).
#define _(String)
GNU gettext support macro.
Definition: platform.h:178
const struct GNUNET_CONFIGURATION_Handle * cfg
The configuration that we are using.
Definition: arm_api.c:112
Information we keep per NAT helper process.

References _, GNUNET_ARM_Handle::cfg, GNUNET_assert, GNUNET_DISK_PF_BLOCKING_RW, GNUNET_DISK_pipe(), GNUNET_DISK_pipe_close(), GNUNET_DISK_pipe_close_end(), GNUNET_DISK_PIPE_END_READ, GNUNET_DISK_PIPE_END_WRITE, GNUNET_DISK_pipe_handle(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_ERROR_TYPE_ERROR, GNUNET_ERROR_TYPE_WARNING, GNUNET_free, GNUNET_log, GNUNET_log_strerror, GNUNET_OS_check_helper_binary(), GNUNET_OS_get_suid_binary_path(), GNUNET_OS_INHERIT_STD_NONE, GNUNET_OS_start_process(), GNUNET_SCHEDULER_add_read_file(), GNUNET_TIME_STD_EXPONENTIAL_BACKOFF_THRESHOLD, GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_YES, h, nat_server_read(), and try_again().

Referenced by GN_start_gnunet_nat_server_(), and try_again().

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◆ try_again()

static void try_again ( struct HelperContext h)
static

Try again starting the helper later.

Parameters
hcontext of the helper

Definition at line 100 of file gnunet-service-nat_helper.c.

101{
102 GNUNET_assert (NULL == h->server_read_task);
103 h->server_retry_delay = GNUNET_TIME_STD_BACKOFF (h->server_retry_delay);
104 h->server_read_task = GNUNET_SCHEDULER_add_delayed (h->server_retry_delay,
106 h);
107}
static void restart_nat_server(void *cls)
Task that restarts the gnunet-helper-nat-server process after a crash after a certain delay.
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:1276
#define GNUNET_TIME_STD_BACKOFF(r)
Perform our standard exponential back-off calculation, starting at 1 ms and then going by a factor of...

References GNUNET_assert, GNUNET_SCHEDULER_add_delayed(), GNUNET_TIME_STD_BACKOFF, h, and restart_nat_server().

Referenced by nat_server_read(), and restart_nat_server().

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◆ nat_server_read()

static void nat_server_read ( void *  cls)
static

We have been notified that gnunet-helper-nat-server has written something to stdout.

Handle the output, then reschedule this function to be called again once more is available.

Parameters
clsthe struct HelperContext

Definition at line 118 of file gnunet-service-nat_helper.c.

119{
120 struct HelperContext *h = cls;
121 char mybuf[40];
122 ssize_t bytes;
123 int port;
124 const char *port_start;
125 struct sockaddr_in sin_addr;
126
127 h->server_read_task = NULL;
128 memset (mybuf, 0, sizeof(mybuf));
129 bytes =
130 GNUNET_DISK_file_read (h->server_stdout_handle, mybuf, sizeof(mybuf));
131 if (bytes < 1)
132 {
134 "Finished reading from server stdout with code: %d\n",
135 (int) bytes);
136 if (0 != GNUNET_OS_process_kill (h->server_proc, GNUNET_TERM_SIG))
138 GNUNET_OS_process_wait (h->server_proc);
139 GNUNET_OS_process_destroy (h->server_proc);
140 h->server_proc = NULL;
141 GNUNET_DISK_pipe_close (h->server_stdout);
142 h->server_stdout = NULL;
143 h->server_stdout_handle = NULL;
144 try_again (h);
145 return;
146 }
147
148 port_start = NULL;
149 for (size_t i = 0; i < sizeof(mybuf); i++)
150 {
151 if (mybuf[i] == '\n')
152 {
153 mybuf[i] = '\0';
154 break;
155 }
156 if ((mybuf[i] == ':') && (i + 1 < sizeof(mybuf)))
157 {
158 mybuf[i] = '\0';
159 port_start = &mybuf[i + 1];
160 }
161 }
162
163 /* construct socket address of sender */
164 memset (&sin_addr, 0, sizeof(sin_addr));
165 sin_addr.sin_family = AF_INET;
166#if HAVE_SOCKADDR_IN_SIN_LEN
167 sin_addr.sin_len = sizeof(sin_addr);
168#endif
169 if ((NULL == port_start) || (1 != sscanf (port_start, "%d", &port)) ||
170 (-1 == inet_pton (AF_INET, mybuf, &sin_addr.sin_addr)))
171 {
172 /* should we restart gnunet-helper-nat-server? */
174 _ (
175 "gnunet-helper-nat-server generated malformed address `%s'\n"),
176 mybuf);
177 h->server_read_task =
179 h->server_stdout_handle,
181 h);
182 return;
183 }
184 sin_addr.sin_port = htons ((uint16_t) port);
186 "gnunet-helper-nat-server read: %s:%d\n",
187 mybuf,
188 port);
189 h->cb (h->cb_cls, &sin_addr);
190 h->server_read_task =
192 h->server_stdout_handle,
194 h);
195}
static uint16_t port
Port number.
Definition: gnunet-bcd.c:146
ssize_t GNUNET_DISK_file_read(const struct GNUNET_DISK_FileHandle *h, void *result, size_t len)
Read the contents of a binary file into a buffer.
Definition: disk.c:645
#define GNUNET_log_from_strerror(level, component, cmd)
Log an error message at log-level 'level' that indicates a failure of the command 'cmd' with the mess...
void GNUNET_OS_process_destroy(struct GNUNET_OS_Process *proc)
Cleans up process structure contents (OS-dependent) and deallocates it.
Definition: os_priority.c:260
int GNUNET_OS_process_kill(struct GNUNET_OS_Process *proc, int sig)
Sends a signal to the process.
Definition: os_priority.c:210
enum GNUNET_GenericReturnValue GNUNET_OS_process_wait(struct GNUNET_OS_Process *proc)
Wait for a process to terminate.
Definition: os_priority.c:871
#define GNUNET_TERM_SIG
The termination signal.
Definition: platform.h:234

References _, GNUNET_DISK_file_read(), GNUNET_DISK_pipe_close(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_ERROR_TYPE_WARNING, GNUNET_log, GNUNET_log_from_strerror, GNUNET_OS_process_destroy(), GNUNET_OS_process_kill(), GNUNET_OS_process_wait(), GNUNET_SCHEDULER_add_read_file(), GNUNET_TERM_SIG, GNUNET_TIME_UNIT_FOREVER_REL, h, nat_server_read(), port, and try_again().

Referenced by nat_server_read(), and restart_nat_server().

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◆ GN_start_gnunet_nat_server_()

struct HelperContext * GN_start_gnunet_nat_server_ ( const struct in_addr *  internal_address,
GN_ReversalCallback  cb,
void *  cb_cls,
const struct GNUNET_CONFIGURATION_Handle cfg 
)

Start the gnunet-helper-nat-server and process incoming requests.

Parameters
internal_address
cbfunction to call if we receive a request
cb_clsclosure for cb
cfghandle to the GNUnet configuration
Returns
NULL on error

Definition at line 269 of file gnunet-service-nat_helper.c.

273{
274 struct HelperContext *h;
275
276 h = GNUNET_new (struct HelperContext);
277 h->cb = cb;
278 h->cb_cls = cb_cls;
279 h->internal_address = *internal_address;
280 h->cfg = cfg;
282 if (NULL == h->server_stdout)
283 {
285 return NULL;
286 }
287 return h;
288}
static struct GNUNET_CONFIGURATION_Handle * cfg
Our configuration.
Definition: gnunet-arm.c:108
void GN_stop_gnunet_nat_server_(struct HelperContext *h)
Start the gnunet-helper-nat-server and process incoming requests.
#define GNUNET_new(type)
Allocate a struct or union of the given type.
struct in_addr internal_address
IP address we pass to the NAT helper.
GN_ReversalCallback cb
Function to call if we receive a reversal request.
void * cb_cls
Closure for cb.

References HelperContext::cb, HelperContext::cb_cls, cfg, GNUNET_ARM_Handle::cfg, GN_stop_gnunet_nat_server_(), GNUNET_new, h, HelperContext::internal_address, and restart_nat_server().

Referenced by run_scan().

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◆ GN_stop_gnunet_nat_server_()

void GN_stop_gnunet_nat_server_ ( struct HelperContext h)

Start the gnunet-helper-nat-server and process incoming requests.

Parameters
hhelper context to stop

Definition at line 298 of file gnunet-service-nat_helper.c.

299{
300 if (NULL != h->server_read_task)
301 {
302 GNUNET_SCHEDULER_cancel (h->server_read_task);
303 h->server_read_task = NULL;
304 }
305 if (NULL != h->server_proc)
306 {
307 if (0 != GNUNET_OS_process_kill (h->server_proc, GNUNET_TERM_SIG))
309 GNUNET_OS_process_wait (h->server_proc);
310 GNUNET_OS_process_destroy (h->server_proc);
311 h->server_proc = NULL;
312 GNUNET_DISK_pipe_close (h->server_stdout);
313 h->server_stdout = NULL;
314 h->server_stdout_handle = NULL;
315 }
316 if (NULL != h->server_stdout)
317 {
318 GNUNET_DISK_pipe_close (h->server_stdout);
319 h->server_stdout = NULL;
320 h->server_stdout_handle = NULL;
321 }
322 GNUNET_free (h);
323}
void * GNUNET_SCHEDULER_cancel(struct GNUNET_SCHEDULER_Task *task)
Cancel the task with the specified identifier.
Definition: scheduler.c:979

References GNUNET_DISK_pipe_close(), GNUNET_ERROR_TYPE_WARNING, GNUNET_free, GNUNET_log_strerror, GNUNET_OS_process_destroy(), GNUNET_OS_process_kill(), GNUNET_OS_process_wait(), GNUNET_SCHEDULER_cancel(), GNUNET_TERM_SIG, and h.

Referenced by free_lal(), and GN_start_gnunet_nat_server_().

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◆ GN_request_connection_reversal()

int GN_request_connection_reversal ( const struct in_addr *  internal_address,
uint16_t  internal_port,
const struct in_addr *  remote_v4,
const struct GNUNET_CONFIGURATION_Handle cfg 
)

We want to connect to a peer that is behind NAT.

Run the gnunet-helper-nat-client to send dummy ICMP responses to cause that peer to connect to us (connection reversal).

Parameters
internal_addressout internal address to use
internal_portport to use
remote_v4the address of the peer (IPv4-only)
cfghandle to the GNUnet configuration
Returns
GNUNET_SYSERR on error, GNUNET_OK otherwise

Definition at line 339 of file gnunet-service-nat_helper.c.

343{
344 char intv4[INET_ADDRSTRLEN];
345 char remv4[INET_ADDRSTRLEN];
346 char port_as_string[6];
347 struct GNUNET_OS_Process *proc;
348 char *binary;
349
350 if (NULL == inet_ntop (AF_INET, internal_address, intv4, INET_ADDRSTRLEN))
351 {
353 return GNUNET_SYSERR;
354 }
355 if (NULL == inet_ntop (AF_INET, remote_v4, remv4, INET_ADDRSTRLEN))
356 {
358 return GNUNET_SYSERR;
359 }
360 GNUNET_snprintf (port_as_string,
361 sizeof(port_as_string),
362 "%d",
363 internal_port);
365 "Running gnunet-helper-nat-client %s %s %u\n",
366 intv4,
367 remv4,
368 internal_port);
369 binary = GNUNET_OS_get_suid_binary_path (cfg, "gnunet-helper-nat-client");
371 NULL,
372 NULL,
373 NULL,
374 binary,
375 "gnunet-helper-nat-client",
376 intv4,
377 remv4,
378 port_as_string,
379 NULL);
380 GNUNET_free (binary);
381 if (NULL == proc)
382 return GNUNET_SYSERR;
383 /* we know that the gnunet-helper-nat-client will terminate virtually
384 * instantly */
387 return GNUNET_OK;
388}
@ GNUNET_OK
@ GNUNET_SYSERR
int GNUNET_snprintf(char *buf, size_t size, const char *format,...) __attribute__((format(printf
Like snprintf, just aborts if the buffer is of insufficient size.

References cfg, GNUNET_ERROR_TYPE_DEBUG, GNUNET_ERROR_TYPE_WARNING, GNUNET_free, GNUNET_log, GNUNET_log_strerror, GNUNET_OK, GNUNET_OS_get_suid_binary_path(), GNUNET_OS_INHERIT_STD_NONE, GNUNET_OS_process_destroy(), GNUNET_OS_process_wait(), GNUNET_OS_start_process(), GNUNET_snprintf(), and GNUNET_SYSERR.

Referenced by handle_request_connection_reversal().

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