4
* This file demonstrates how to use Avahi's core API, this is
5
* the embeddable mDNS stack for embedded applications.
7
* End user applications should *not* use this API and should use
8
* the D-Bus or C APIs, please see
9
* client-browse-services.c and glib-integration.c
11
* I repeat, you probably do *not* want to use this example.
15
This file is part of avahi.
17
avahi is free software; you can redistribute it and/or modify it
18
under the terms of the GNU Lesser General Public License as
19
published by the Free Software Foundation; either version 2.1 of the
20
License, or (at your option) any later version.
22
avahi is distributed in the hope that it will be useful, but WITHOUT
23
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
24
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
25
Public License for more details.
27
You should have received a copy of the GNU Lesser General Public
28
License along with avahi; if not, write to the Free Software
29
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
33
#define _LARGEFILE_SOURCE
34
#define _FILE_OFFSET_BITS 64
40
#include <net/if.h> /* if_nametoindex */
42
#include <avahi-core/core.h>
43
#include <avahi-core/lookup.h>
44
#include <avahi-core/log.h>
45
#include <avahi-common/simple-watch.h>
46
#include <avahi-common/malloc.h>
47
#include <avahi-common/error.h>
50
#include <sys/types.h> /* socket(), setsockopt(), inet_pton() */
51
#include <sys/socket.h> /* socket(), setsockopt(), struct sockaddr_in6, struct in6_addr, inet_pton() */
52
#include <gnutls/gnutls.h> /* ALL GNUTLS STUFF */
53
#include <gnutls/openpgp.h> /* gnutls with openpgp stuff */
55
#include <unistd.h> /* close() */
56
#include <netinet/in.h>
57
#include <stdbool.h> /* true */
58
#include <string.h> /* memset */
59
#include <arpa/inet.h> /* inet_pton() */
60
#include <iso646.h> /* not */
63
#include <errno.h> /* perror() */
68
#define CERT_ROOT "/conf/conf.d/cryptkeyreq/"
70
#define CERTFILE CERT_ROOT "openpgp-client.txt"
71
#define KEYFILE CERT_ROOT "openpgp-client-key.txt"
72
#define BUFFER_SIZE 256
76
gnutls_session_t session;
77
gnutls_certificate_credentials_t cred;
78
gnutls_dh_params_t dh_params;
82
ssize_t gpg_packet_decrypt (char *packet, size_t packet_size, char **new_packet, char *homedir){
83
gpgme_data_t dh_crypto, dh_plain;
87
size_t new_packet_capacity = 0;
88
size_t new_packet_length = 0;
89
gpgme_engine_info_t engine_info;
92
gpgme_check_version(NULL);
93
gpgme_engine_check_version(GPGME_PROTOCOL_OpenPGP);
95
/* Set GPGME home directory */
96
rc = gpgme_get_engine_info (&engine_info);
97
if (rc != GPG_ERR_NO_ERROR){
98
fprintf(stderr, "bad gpgme_get_engine_info: %s: %s\n",
99
gpgme_strsource(rc), gpgme_strerror(rc));
102
while(engine_info != NULL){
103
if(engine_info->protocol == GPGME_PROTOCOL_OpenPGP){
104
gpgme_set_engine_info(GPGME_PROTOCOL_OpenPGP,
105
engine_info->file_name, homedir);
108
engine_info = engine_info->next;
110
if(engine_info == NULL){
111
fprintf(stderr, "Could not set home dir to %s\n", homedir);
115
/* Create new GPGME data buffer from packet buffer */
116
rc = gpgme_data_new_from_mem(&dh_crypto, packet, packet_size, 0);
117
if (rc != GPG_ERR_NO_ERROR){
118
fprintf(stderr, "bad gpgme_data_new_from_mem: %s: %s\n",
119
gpgme_strsource(rc), gpgme_strerror(rc));
123
/* Create new empty GPGME data buffer for the plaintext */
124
rc = gpgme_data_new(&dh_plain);
125
if (rc != GPG_ERR_NO_ERROR){
126
fprintf(stderr, "bad gpgme_data_new: %s: %s\n",
127
gpgme_strsource(rc), gpgme_strerror(rc));
131
/* Create new GPGME "context" */
132
rc = gpgme_new(&ctx);
133
if (rc != GPG_ERR_NO_ERROR){
134
fprintf(stderr, "bad gpgme_new: %s: %s\n",
135
gpgme_strsource(rc), gpgme_strerror(rc));
139
/* Decrypt data from the FILE pointer to the plaintext data buffer */
140
rc = gpgme_op_decrypt(ctx, dh_crypto, dh_plain);
141
if (rc != GPG_ERR_NO_ERROR){
142
fprintf(stderr, "bad gpgme_op_decrypt: %s: %s\n",
143
gpgme_strsource(rc), gpgme_strerror(rc));
147
/* gpgme_decrypt_result_t result; */
148
/* result = gpgme_op_decrypt_result(ctx); */
149
/* fprintf(stderr, "Unsupported algorithm: %s\n", result->unsupported_algorithm); */
150
/* fprintf(stderr, "Wrong key usage: %d\n", result->wrong_key_usage); */
151
/* if(result->file_name != NULL){ */
152
/* fprintf(stderr, "File name: %s\n", result->file_name); */
154
/* gpgme_recipient_t recipient; */
155
/* recipient = result->recipients; */
157
/* while(recipient != NULL){ */
158
/* fprintf(stderr, "Public key algorithm: %s\n", */
159
/* gpgme_pubkey_algo_name(recipient->pubkey_algo)); */
160
/* fprintf(stderr, "Key ID: %s\n", recipient->keyid); */
161
/* fprintf(stderr, "Secret key available: %s\n", */
162
/* recipient->status == GPG_ERR_NO_SECKEY ? "No" : "Yes"); */
163
/* recipient = recipient->next; */
167
/* Delete the GPGME FILE pointer cryptotext data buffer */
168
gpgme_data_release(dh_crypto);
170
/* Seek back to the beginning of the GPGME plaintext data buffer */
171
gpgme_data_seek(dh_plain, 0, SEEK_SET);
175
if (new_packet_length + BUFFER_SIZE > new_packet_capacity){
176
*new_packet = realloc(*new_packet, new_packet_capacity + BUFFER_SIZE);
177
if (*new_packet == NULL){
181
new_packet_capacity += BUFFER_SIZE;
184
ret = gpgme_data_read(dh_plain, *new_packet + new_packet_length, BUFFER_SIZE);
185
/* Print the data, if any */
187
/* If password is empty, then a incorrect error will be printed */
191
perror("gpgme_data_read");
194
new_packet_length += ret;
197
/* Delete the GPGME plaintext data buffer */
198
gpgme_data_release(dh_plain);
199
return new_packet_length;
202
static const char * safer_gnutls_strerror (int value) {
203
const char *ret = gnutls_strerror (value);
209
void debuggnutls(int level, const char* string){
210
fprintf(stderr, "%s", string);
213
int initgnutls(encrypted_session *es){
217
if ((ret = gnutls_global_init ())
218
!= GNUTLS_E_SUCCESS) {
219
fprintf (stderr, "global_init: %s\n", safer_gnutls_strerror(ret));
223
/* Uncomment to enable full debuggin on the gnutls library */
224
/* gnutls_global_set_log_level(11); */
225
/* gnutls_global_set_log_function(debuggnutls); */
228
/* openpgp credentials */
229
if ((ret = gnutls_certificate_allocate_credentials (&es->cred))
230
!= GNUTLS_E_SUCCESS) {
231
fprintf (stderr, "memory error: %s\n", safer_gnutls_strerror(ret));
235
ret = gnutls_certificate_set_openpgp_key_file
236
(es->cred, CERTFILE, KEYFILE, GNUTLS_OPENPGP_FMT_BASE64);
237
if (ret != GNUTLS_E_SUCCESS) {
239
(stderr, "Error[%d] while reading the OpenPGP key pair ('%s', '%s')\n",
240
ret, CERTFILE, KEYFILE);
241
fprintf(stdout, "The Error is: %s\n",
242
safer_gnutls_strerror(ret));
246
//Gnutls server initialization
247
if ((ret = gnutls_dh_params_init (&es->dh_params))
248
!= GNUTLS_E_SUCCESS) {
249
fprintf (stderr, "Error in dh parameter initialization: %s\n",
250
safer_gnutls_strerror(ret));
254
if ((ret = gnutls_dh_params_generate2 (es->dh_params, DH_BITS))
255
!= GNUTLS_E_SUCCESS) {
256
fprintf (stderr, "Error in prime generation: %s\n",
257
safer_gnutls_strerror(ret));
261
gnutls_certificate_set_dh_params (es->cred, es->dh_params);
263
// Gnutls session creation
264
if ((ret = gnutls_init (&es->session, GNUTLS_SERVER))
265
!= GNUTLS_E_SUCCESS){
266
fprintf(stderr, "Error in gnutls session initialization: %s\n",
267
safer_gnutls_strerror(ret));
270
if ((ret = gnutls_priority_set_direct (es->session, "NORMAL", &err))
271
!= GNUTLS_E_SUCCESS) {
272
fprintf(stderr, "Syntax error at: %s\n", err);
273
fprintf(stderr, "Gnutls error: %s\n",
274
safer_gnutls_strerror(ret));
278
if ((ret = gnutls_credentials_set
279
(es->session, GNUTLS_CRD_CERTIFICATE, es->cred))
280
!= GNUTLS_E_SUCCESS) {
281
fprintf(stderr, "Error setting a credentials set: %s\n",
282
safer_gnutls_strerror(ret));
286
/* ignore client certificate if any. */
287
gnutls_certificate_server_set_request (es->session, GNUTLS_CERT_IGNORE);
289
gnutls_dh_set_prime_bits (es->session, DH_BITS);
294
void empty_log(AvahiLogLevel level, const char *txt){}
296
int start_mandos_communcation(char *ip, uint16_t port){
298
struct sockaddr_in6 to;
299
struct in6_addr ip_addr;
300
encrypted_session es;
302
char *decrypted_buffer;
303
size_t buffer_length = 0;
304
size_t buffer_capacity = 0;
305
ssize_t decrypted_buffer_size;
309
tcp_sd = socket(PF_INET6, SOCK_STREAM, 0);
315
ret = setsockopt(tcp_sd, SOL_SOCKET, SO_BINDTODEVICE, "eth0", 5);
317
perror("setsockopt bindtodevice");
321
memset(&to,0,sizeof(to));
322
to.sin6_family = AF_INET6;
323
ret = inet_pton(AF_INET6, ip, &ip_addr);
329
fprintf(stderr, "Bad address: %s\n", ip);
332
to.sin6_port = htons(port);
333
to.sin6_scope_id = if_nametoindex("eth0");
335
ret = connect(tcp_sd, (struct sockaddr *) &to, sizeof(to));
341
ret = initgnutls (&es);
348
gnutls_transport_set_ptr (es.session, (gnutls_transport_ptr_t) tcp_sd);
350
ret = gnutls_handshake (es.session);
352
if (ret != GNUTLS_E_SUCCESS){
353
fprintf(stderr, "\n*** Handshake failed ***\n");
361
if (buffer_length + BUFFER_SIZE > buffer_capacity){
362
buffer = realloc(buffer, buffer_capacity + BUFFER_SIZE);
367
buffer_capacity += BUFFER_SIZE;
370
ret = gnutls_record_recv
371
(es.session, buffer+buffer_length, BUFFER_SIZE);
377
case GNUTLS_E_INTERRUPTED:
380
case GNUTLS_E_REHANDSHAKE:
381
ret = gnutls_handshake (es.session);
383
fprintf(stderr, "\n*** Handshake failed ***\n");
390
fprintf(stderr, "Unknown error while reading data from encrypted session with mandos server\n");
392
gnutls_bye (es.session, GNUTLS_SHUT_RDWR);
396
buffer_length += ret;
400
if (buffer_length > 0){
401
if ((decrypted_buffer_size = gpg_packet_decrypt(buffer, buffer_length, &decrypted_buffer, CERT_ROOT)) == 0){
404
fwrite (decrypted_buffer, 1, decrypted_buffer_size, stdout);
405
free(decrypted_buffer);
412
gnutls_bye (es.session, GNUTLS_SHUT_RDWR);
415
gnutls_deinit (es.session);
416
gnutls_certificate_free_credentials (es.cred);
417
gnutls_global_deinit ();
421
static AvahiSimplePoll *simple_poll = NULL;
422
static AvahiServer *server = NULL;
424
static void resolve_callback(
425
AvahiSServiceResolver *r,
426
AVAHI_GCC_UNUSED AvahiIfIndex interface,
427
AVAHI_GCC_UNUSED AvahiProtocol protocol,
428
AvahiResolverEvent event,
432
const char *host_name,
433
const AvahiAddress *address,
435
AvahiStringList *txt,
436
AvahiLookupResultFlags flags,
437
AVAHI_GCC_UNUSED void* userdata) {
441
/* Called whenever a service has been resolved successfully or timed out */
444
case AVAHI_RESOLVER_FAILURE:
445
fprintf(stderr, "(Resolver) Failed to resolve service '%s' of type '%s' in domain '%s': %s\n", name, type, domain, avahi_strerror(avahi_server_errno(server)));
448
case AVAHI_RESOLVER_FOUND: {
449
char ip[AVAHI_ADDRESS_STR_MAX];
450
avahi_address_snprint(ip, sizeof(ip), address);
451
int ret = start_mandos_communcation(ip, port);
459
avahi_s_service_resolver_free(r);
462
static void browse_callback(
463
AvahiSServiceBrowser *b,
464
AvahiIfIndex interface,
465
AvahiProtocol protocol,
466
AvahiBrowserEvent event,
470
AVAHI_GCC_UNUSED AvahiLookupResultFlags flags,
473
AvahiServer *s = userdata;
476
/* Called whenever a new services becomes available on the LAN or is removed from the LAN */
480
case AVAHI_BROWSER_FAILURE:
482
fprintf(stderr, "(Browser) %s\n", avahi_strerror(avahi_server_errno(server)));
483
avahi_simple_poll_quit(simple_poll);
486
case AVAHI_BROWSER_NEW:
487
/* We ignore the returned resolver object. In the callback
488
function we free it. If the server is terminated before
489
the callback function is called the server will free
490
the resolver for us. */
492
if (!(avahi_s_service_resolver_new(s, interface, protocol, name, type, domain, AVAHI_PROTO_INET6, 0, resolve_callback, s)))
493
fprintf(stderr, "Failed to resolve service '%s': %s\n", name, avahi_strerror(avahi_server_errno(s)));
497
case AVAHI_BROWSER_REMOVE:
500
case AVAHI_BROWSER_ALL_FOR_NOW:
501
case AVAHI_BROWSER_CACHE_EXHAUSTED:
506
int main(AVAHI_GCC_UNUSED int argc, AVAHI_GCC_UNUSED char*argv[]) {
507
AvahiServerConfig config;
508
AvahiSServiceBrowser *sb = NULL;
512
avahi_set_log_function(empty_log);
514
/* Initialize the psuedo-RNG */
517
/* Allocate main loop object */
518
if (!(simple_poll = avahi_simple_poll_new())) {
519
fprintf(stderr, "Failed to create simple poll object.\n");
523
/* Do not publish any local records */
524
avahi_server_config_init(&config);
525
config.publish_hinfo = 0;
526
config.publish_addresses = 0;
527
config.publish_workstation = 0;
528
config.publish_domain = 0;
530
/* /\* Set a unicast DNS server for wide area DNS-SD *\/ */
531
/* avahi_address_parse("193.11.177.11", AVAHI_PROTO_UNSPEC, &config.wide_area_servers[0]); */
532
/* config.n_wide_area_servers = 1; */
533
/* config.enable_wide_area = 1; */
535
/* Allocate a new server */
536
server = avahi_server_new(avahi_simple_poll_get(simple_poll), &config, NULL, NULL, &error);
538
/* Free the configuration data */
539
avahi_server_config_free(&config);
541
/* Check wether creating the server object succeeded */
543
fprintf(stderr, "Failed to create server: %s\n", avahi_strerror(error));
547
/* Create the service browser */
548
if (!(sb = avahi_s_service_browser_new(server, if_nametoindex("eth0"), AVAHI_PROTO_INET6, "_mandos._tcp", NULL, 0, browse_callback, server))) {
549
fprintf(stderr, "Failed to create service browser: %s\n", avahi_strerror(avahi_server_errno(server)));
553
/* Run the main loop */
554
avahi_simple_poll_loop(simple_poll);
562
avahi_s_service_browser_free(sb);
565
avahi_server_free(server);
568
avahi_simple_poll_free(simple_poll);