32
32
/* Needed by GPGME, specifically gpgme_data_seek() */
33
#ifndef _LARGEFILE_SOURCE
34
33
#define _LARGEFILE_SOURCE
36
#ifndef _FILE_OFFSET_BITS
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34
#define _FILE_OFFSET_BITS 64
40
36
#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), asprintf() */
42
38
#include <stdio.h> /* fprintf(), stderr, fwrite(),
43
stdout, ferror(), remove() */
39
stdout, ferror(), sscanf(),
44
41
#include <stdint.h> /* uint16_t, uint32_t */
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#include <stddef.h> /* NULL, size_t, ssize_t */
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#include <stdlib.h> /* free(), EXIT_SUCCESS, srand(),
43
#include <stdlib.h> /* free(), EXIT_SUCCESS, EXIT_FAILURE,
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45
#include <stdbool.h> /* bool, false, true */
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#include <string.h> /* memset(), strcmp(), strlen(),
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strerror(), asprintf(), strcpy() */
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#include <fcntl.h> /* open() */
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#include <dirent.h> /* opendir(), struct dirent, readdir()
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#include <inttypes.h> /* PRIu16, PRIdMAX, intmax_t,
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#include <inttypes.h> /* PRIu16, intmax_t, SCNdMAX */
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#include <assert.h> /* assert() */
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#include <errno.h> /* perror(), errno */
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#include <time.h> /* nanosleep(), time(), sleep() */
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#include <time.h> /* nanosleep(), time() */
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#include <net/if.h> /* ioctl, ifreq, SIOCGIFFLAGS, IFF_UP,
68
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SIOCSIFFLAGS, if_indextoname(),
69
65
if_nametoindex(), IF_NAMESIZE */
71
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INET_ADDRSTRLEN, INET6_ADDRSTRLEN
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#include <unistd.h> /* close(), SEEK_SET, off_t, write(),
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getuid(), getgid(), seteuid(),
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getuid(), getgid(), setuid(),
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#include <arpa/inet.h> /* inet_pton(), htons */
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#include <iso646.h> /* not, or, and */
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74
#include <argp.h> /* struct argp_option, error_t, struct
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argp_state, struct argp,
80
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argp_parse(), ARGP_KEY_ARG,
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ARGP_KEY_END, ARGP_ERR_UNKNOWN */
82
#include <signal.h> /* sigemptyset(), sigaddset(),
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sigaction(), SIGTERM, sig_atomic_t,
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#include <sysexits.h> /* EX_OSERR, EX_USAGE, EX_UNAVAILABLE,
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EX_NOHOST, EX_IOERR, EX_PROTOCOL */
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#include <sys/klog.h> /* klogctl() */
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#endif /* __linux__ */
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/* All Avahi types, constants and functions
142
130
} mandos_context;
144
/* global context so signal handler can reach it*/
145
mandos_context mc = { .simple_poll = NULL, .server = NULL,
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.dh_bits = 1024, .priority = "SECURE256"
147
":!CTYPE-X.509:+CTYPE-OPENPGP" };
149
sig_atomic_t quit_now = 0;
150
int signal_received = 0;
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* Make additional room in "buffer" for at least BUFFER_SIZE more
154
* bytes. "buffer_capacity" is how much is currently allocated,
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* Make room in "buffer" for at least BUFFER_SIZE additional bytes.
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* "buffer_capacity" is how much is currently allocated,
155
135
* "buffer_length" is how much is already used.
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size_t incbuffer(char **buffer, size_t buffer_length,
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size_t adjustbuffer(char **buffer, size_t buffer_length,
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138
size_t buffer_capacity){
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if(buffer_length + BUFFER_SIZE > buffer_capacity){
160
140
*buffer = realloc(*buffer, buffer_capacity + BUFFER_SIZE);
317
298
gpgme_recipient_t recipient;
318
299
recipient = result->recipients;
319
while(recipient != NULL){
320
fprintf(stderr, "Public key algorithm: %s\n",
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gpgme_pubkey_algo_name(recipient->pubkey_algo));
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fprintf(stderr, "Key ID: %s\n", recipient->keyid);
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fprintf(stderr, "Secret key available: %s\n",
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recipient->status == GPG_ERR_NO_SECKEY
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recipient = recipient->next;
301
while(recipient != NULL){
302
fprintf(stderr, "Public key algorithm: %s\n",
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gpgme_pubkey_algo_name(recipient->pubkey_algo));
304
fprintf(stderr, "Key ID: %s\n", recipient->keyid);
305
fprintf(stderr, "Secret key available: %s\n",
306
recipient->status == GPG_ERR_NO_SECKEY
308
recipient = recipient->next;
455
439
/* GnuTLS server initialization */
456
ret = gnutls_dh_params_init(&mc.dh_params);
440
ret = gnutls_dh_params_init(&mc->dh_params);
457
441
if(ret != GNUTLS_E_SUCCESS){
458
442
fprintf(stderr, "Error in GnuTLS DH parameter initialization:"
459
443
" %s\n", safer_gnutls_strerror(ret));
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ret = gnutls_dh_params_generate2(mc.dh_params, mc.dh_bits);
446
ret = gnutls_dh_params_generate2(mc->dh_params, mc->dh_bits);
463
447
if(ret != GNUTLS_E_SUCCESS){
464
448
fprintf(stderr, "Error in GnuTLS prime generation: %s\n",
465
449
safer_gnutls_strerror(ret));
469
gnutls_certificate_set_dh_params(mc.cred, mc.dh_params);
453
gnutls_certificate_set_dh_params(mc->cred, mc->dh_params);
475
gnutls_certificate_free_credentials(mc.cred);
459
gnutls_certificate_free_credentials(mc->cred);
476
460
gnutls_global_deinit();
477
gnutls_dh_params_deinit(mc.dh_params);
461
gnutls_dh_params_deinit(mc->dh_params);
481
static int init_gnutls_session(gnutls_session_t *session){
465
static int init_gnutls_session(mandos_context *mc,
466
gnutls_session_t *session){
483
468
/* GnuTLS session creation */
485
ret = gnutls_init(session, GNUTLS_SERVER);
489
} while(ret == GNUTLS_E_INTERRUPTED or ret == GNUTLS_E_AGAIN);
469
ret = gnutls_init(session, GNUTLS_SERVER);
490
470
if(ret != GNUTLS_E_SUCCESS){
491
471
fprintf(stderr, "Error in GnuTLS session initialization: %s\n",
492
472
safer_gnutls_strerror(ret));
836
730
fprintf(stderr, "Closing TLS session\n");
845
ret = gnutls_bye(session, GNUTLS_SHUT_RDWR);
850
} while(ret == GNUTLS_E_AGAIN or ret == GNUTLS_E_INTERRUPTED);
733
gnutls_bye(session, GNUTLS_SHUT_RDWR);
852
735
if(buffer_length > 0){
853
ssize_t decrypted_buffer_size;
854
decrypted_buffer_size = pgp_packet_decrypt(buffer,
736
decrypted_buffer_size = pgp_packet_decrypt(mc, buffer,
856
738
&decrypted_buffer);
857
739
if(decrypted_buffer_size >= 0){
860
741
while(written < (size_t) decrypted_buffer_size){
866
742
ret = (int)fwrite(decrypted_buffer + written, 1,
867
743
(size_t)decrypted_buffer_size - written,
869
745
if(ret == 0 and ferror(stdout)){
872
747
fprintf(stderr, "Error writing encrypted data: %s\n",
873
748
strerror(errno));
878
753
written += (size_t)ret;
755
free(decrypted_buffer);
884
763
/* Shutdown procedure */
889
free(decrypted_buffer);
892
ret = (int)TEMP_FAILURE_RETRY(close(tcp_sd));
900
gnutls_deinit(session);
767
ret = (int)TEMP_FAILURE_RETRY(close(tcp_sd));
771
gnutls_deinit(session);
991
850
the callback function is called the Avahi server will free the
992
851
resolver for us. */
994
if(avahi_s_service_resolver_new(mc.server, interface, protocol,
995
name, type, domain, protocol, 0,
996
resolve_callback, NULL) == NULL)
853
if(!(avahi_s_service_resolver_new(mc->server, interface,
854
protocol, name, type, domain,
855
AVAHI_PROTO_INET6, 0,
856
resolve_callback, mc)))
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fprintf(stderr, "Avahi: Failed to resolve service '%s': %s\n",
998
name, avahi_strerror(avahi_server_errno(mc.server)));
858
name, avahi_strerror(avahi_server_errno(mc->server)));
1001
861
case AVAHI_BROWSER_REMOVE:
1013
/* stop main loop after sigterm has been called */
1014
static void handle_sigterm(int sig){
1019
signal_received = sig;
1020
int old_errno = errno;
1021
if(mc.simple_poll != NULL){
1022
avahi_simple_poll_quit(mc.simple_poll);
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* This function determines if a directory entry in /sys/class/net
1029
* corresponds to an acceptable network device.
1030
* (This function is passed to scandir(3) as a filter function.)
1032
int good_interface(const struct dirent *if_entry){
1034
char *flagname = NULL;
1035
if(if_entry->d_name[0] == '.'){
1038
int ret = asprintf(&flagname, "%s/%s/flags", sys_class_net,
1044
int flags_fd = (int)TEMP_FAILURE_RETRY(open(flagname, O_RDONLY));
1051
typedef short ifreq_flags; /* ifreq.ifr_flags in netdevice(7) */
1052
/* read line from flags_fd */
1053
ssize_t to_read = (sizeof(ifreq_flags)*2)+3; /* "0x1003\n" */
1054
char *flagstring = malloc((size_t)to_read+1); /* +1 for final \0 */
1055
flagstring[(size_t)to_read] = '\0';
1056
if(flagstring == NULL){
1062
ssret = (ssize_t)TEMP_FAILURE_RETRY(read(flags_fd, flagstring,
1079
tmpmax = strtoimax(flagstring, &tmp, 0);
1080
if(errno != 0 or tmp == flagstring or (*tmp != '\0'
1081
and not (isspace(*tmp)))
1082
or tmpmax != (ifreq_flags)tmpmax){
1084
fprintf(stderr, "Invalid flags \"%s\" for interface \"%s\"\n",
1085
flagstring, if_entry->d_name);
1091
ifreq_flags flags = (ifreq_flags)tmpmax;
1092
/* Reject the loopback device */
1093
if(flags & IFF_LOOPBACK){
1095
fprintf(stderr, "Rejecting loopback interface \"%s\"\n",
1100
/* Accept point-to-point devices only if connect_to is specified */
1101
if(connect_to != NULL and (flags & IFF_POINTOPOINT)){
1103
fprintf(stderr, "Accepting point-to-point interface \"%s\"\n",
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/* Otherwise, reject non-broadcast-capable devices */
1109
if(not (flags & IFF_BROADCAST)){
1111
fprintf(stderr, "Rejecting non-broadcast interface \"%s\"\n",
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/* Accept this device */
1118
fprintf(stderr, "Interface \"%s\" is acceptable\n",
1124
873
int main(int argc, char *argv[]){
1125
874
AvahiSServiceBrowser *sb = NULL;
1128
877
intmax_t tmpmax;
1130
879
int exitcode = EXIT_SUCCESS;
1131
const char *interface = "";
880
const char *interface = "eth0";
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881
struct ifreq network;
1134
bool take_down_interface = false;
885
char *connect_to = NULL;
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char tempdir[] = "/tmp/mandosXXXXXX";
1138
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bool tempdir_created = false;
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AvahiIfIndex if_index = AVAHI_IF_UNSPEC;
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const char *seckey = PATHDIR "/" SECKEY;
1141
890
const char *pubkey = PATHDIR "/" PUBKEY;
892
mandos_context mc = { .simple_poll = NULL, .server = NULL,
893
.dh_bits = 1024, .priority = "SECURE256"
894
":!CTYPE-X.509:+CTYPE-OPENPGP" };
1143
895
bool gnutls_initialized = false;
1144
896
bool gpgme_initialized = false;
1147
struct sigaction old_sigterm_action = { .sa_handler = SIG_DFL };
1148
struct sigaction sigterm_action = { .sa_handler = handle_sigterm };
1153
/* Lower any group privileges we might have, just to be safe */
1160
/* Lower user privileges (temporarily) */
1172
900
struct argp_option options[] = {
1202
930
.arg = "SECONDS",
1203
931
.doc = "Maximum delay to wait for interface startup",
1206
* These reproduce what we would get without ARGP_NO_HELP
1208
{ .name = "help", .key = '?',
1209
.doc = "Give this help list", .group = -1 },
1210
{ .name = "usage", .key = -3,
1211
.doc = "Give a short usage message", .group = -1 },
1212
{ .name = "version", .key = 'V',
1213
.doc = "Print program version", .group = -1 },
1214
933
{ .name = NULL }
1217
936
error_t parse_opt(int key, char *arg,
1218
937
struct argp_state *state){
1221
939
case 128: /* --debug */
1246
964
mc.priority = arg;
1248
966
case 131: /* --delay */
1250
delay = strtof(arg, &tmp);
1251
if(errno != 0 or tmp == arg or *tmp != '\0'){
1252
argp_error(state, "Bad delay");
967
ret = sscanf(arg, "%lf%n", &delay, &numchars);
968
if(ret < 1 or arg[numchars] != '\0'){
969
fprintf(stderr, "Bad delay\n");
1256
* These reproduce what we would get without ARGP_NO_HELP
1258
case '?': /* --help */
1259
argp_state_help(state, state->out_stream,
1260
(ARGP_HELP_STD_HELP | ARGP_HELP_EXIT_ERR)
1261
& ~(unsigned int)ARGP_HELP_EXIT_OK);
1262
case -3: /* --usage */
1263
argp_state_help(state, state->out_stream,
1264
ARGP_HELP_USAGE | ARGP_HELP_EXIT_ERR);
1265
case 'V': /* --version */
1266
fprintf(state->out_stream, "%s\n", argp_program_version);
1267
exit(argp_err_exit_status);
1270
978
return ARGP_ERR_UNKNOWN;
1275
983
struct argp argp = { .options = options, .parser = parse_opt,
1277
985
.doc = "Mandos client -- Get and decrypt"
1278
986
" passwords from a Mandos server" };
1279
ret = argp_parse(&argp, argc, argv,
1280
ARGP_IN_ORDER | ARGP_NO_HELP, 0, NULL);
1287
perror("argp_parse");
1288
exitcode = EX_OSERR;
1291
exitcode = EX_USAGE;
1297
avahi_set_log_function(empty_log);
1300
if(interface[0] == '\0'){
1301
struct dirent **direntries;
1302
ret = scandir(sys_class_net, &direntries, good_interface,
1305
/* Pick the first good interface */
1306
interface = strdup(direntries[0]->d_name);
1308
fprintf(stderr, "Using interface \"%s\"\n", interface);
1310
if(interface == NULL){
1313
exitcode = EXIT_FAILURE;
1319
fprintf(stderr, "Could not find a network interface\n");
987
ret = argp_parse(&argp, argc, argv, 0, 0, NULL);
988
if(ret == ARGP_ERR_UNKNOWN){
989
fprintf(stderr, "Unknown error while parsing arguments\n");
1320
990
exitcode = EXIT_FAILURE;
1325
/* Initialize Avahi early so avahi_simple_poll_quit() can be called
1326
from the signal handler */
1327
/* Initialize the pseudo-RNG for Avahi */
1328
srand((unsigned int) time(NULL));
1329
mc.simple_poll = avahi_simple_poll_new();
1330
if(mc.simple_poll == NULL){
1331
fprintf(stderr, "Avahi: Failed to create simple poll object.\n");
1332
exitcode = EX_UNAVAILABLE;
1336
sigemptyset(&sigterm_action.sa_mask);
1337
ret = sigaddset(&sigterm_action.sa_mask, SIGINT);
1339
perror("sigaddset");
1340
exitcode = EX_OSERR;
1343
ret = sigaddset(&sigterm_action.sa_mask, SIGHUP);
1345
perror("sigaddset");
1346
exitcode = EX_OSERR;
1349
ret = sigaddset(&sigterm_action.sa_mask, SIGTERM);
1351
perror("sigaddset");
1352
exitcode = EX_OSERR;
1355
/* Need to check if the handler is SIG_IGN before handling:
1356
| [[info:libc:Initial Signal Actions]] |
1357
| [[info:libc:Basic Signal Handling]] |
1359
ret = sigaction(SIGINT, NULL, &old_sigterm_action);
1361
perror("sigaction");
1364
if(old_sigterm_action.sa_handler != SIG_IGN){
1365
ret = sigaction(SIGINT, &sigterm_action, NULL);
1367
perror("sigaction");
1368
exitcode = EX_OSERR;
1372
ret = sigaction(SIGHUP, NULL, &old_sigterm_action);
1374
perror("sigaction");
1377
if(old_sigterm_action.sa_handler != SIG_IGN){
1378
ret = sigaction(SIGHUP, &sigterm_action, NULL);
1380
perror("sigaction");
1381
exitcode = EX_OSERR;
1385
ret = sigaction(SIGTERM, NULL, &old_sigterm_action);
1387
perror("sigaction");
1390
if(old_sigterm_action.sa_handler != SIG_IGN){
1391
ret = sigaction(SIGTERM, &sigterm_action, NULL);
1393
perror("sigaction");
1394
exitcode = EX_OSERR;
1399
995
/* If the interface is down, bring it up */
1400
if(strcmp(interface, "none") != 0){
1401
if_index = (AvahiIfIndex) if_nametoindex(interface);
1403
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1404
exitcode = EX_UNAVAILABLE;
1412
/* Re-raise priviliges */
996
if(interface[0] != '\0'){
1419
997
#ifdef __linux__
1420
998
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
1421
messages about the network interface to mess up the prompt */
999
messages to mess up the prompt */
1422
1000
ret = klogctl(8, NULL, 5);
1423
1001
bool restore_loglevel = true;
1425
1003
restore_loglevel = false;
1426
1004
perror("klogctl");
1428
#endif /* __linux__ */
1430
1008
sd = socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP);
1432
1010
perror("socket");
1433
exitcode = EX_OSERR;
1011
exitcode = EXIT_FAILURE;
1434
1012
#ifdef __linux__
1435
1013
if(restore_loglevel){
1436
1014
ret = klogctl(7, NULL, 0);
1522
1077
perror("klogctl");
1525
#endif /* __linux__ */
1526
/* Lower privileges */
1528
if(take_down_interface){
1529
/* Lower privileges */
1535
/* Lower privileges permanently */
1547
ret = init_gnutls_global(pubkey, seckey);
1097
ret = init_gnutls_global(&mc, pubkey, seckey);
1549
1099
fprintf(stderr, "init_gnutls_global failed\n");
1550
exitcode = EX_UNAVAILABLE;
1100
exitcode = EXIT_FAILURE;
1553
1103
gnutls_initialized = true;
1560
tempdir_created = true;
1561
1106
if(mkdtemp(tempdir) == NULL){
1562
tempdir_created = false;
1563
1107
perror("mkdtemp");
1571
if(not init_gpgme(pubkey, seckey, tempdir)){
1110
tempdir_created = true;
1112
if(not init_gpgme(&mc, pubkey, seckey, tempdir)){
1572
1113
fprintf(stderr, "init_gpgme failed\n");
1573
exitcode = EX_UNAVAILABLE;
1114
exitcode = EXIT_FAILURE;
1576
1117
gpgme_initialized = true;
1120
if(interface[0] != '\0'){
1121
if_index = (AvahiIfIndex) if_nametoindex(interface);
1123
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1124
exitcode = EXIT_FAILURE;
1583
1129
if(connect_to != NULL){
1664
1200
if(mc.server == NULL){
1665
1201
fprintf(stderr, "Failed to create Avahi server: %s\n",
1666
1202
avahi_strerror(error));
1667
exitcode = EX_UNAVAILABLE;
1203
exitcode = EXIT_FAILURE;
1675
1207
/* Create the Avahi service browser */
1676
1208
sb = avahi_s_service_browser_new(mc.server, if_index,
1677
AVAHI_PROTO_UNSPEC, "_mandos._tcp",
1678
NULL, 0, browse_callback, NULL);
1209
AVAHI_PROTO_INET6, "_mandos._tcp",
1210
NULL, 0, browse_callback, &mc);
1679
1211
if(sb == NULL){
1680
1212
fprintf(stderr, "Failed to create service browser: %s\n",
1681
1213
avahi_strerror(avahi_server_errno(mc.server)));
1682
exitcode = EX_UNAVAILABLE;
1214
exitcode = EXIT_FAILURE;