32
33
#define _LARGEFILE_SOURCE
33
34
#define _FILE_OFFSET_BITS 64
39
#include <net/if.h> /* if_nametoindex */
40
#include <sys/ioctl.h> /* ioctl, ifreq, SIOCGIFFLAGS, IFF_UP,
36
#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), asprintf() */
38
#include <stdio.h> /* fprintf(), stderr, fwrite(),
39
stdout, ferror(), sscanf(),
41
#include <stdint.h> /* uint16_t, uint32_t */
42
#include <stddef.h> /* NULL, size_t, ssize_t */
43
#include <stdlib.h> /* free(), EXIT_SUCCESS, EXIT_FAILURE,
45
#include <stdbool.h> /* bool, true */
46
#include <string.h> /* memset(), strcmp(), strlen(),
47
strerror(), asprintf(), strcpy() */
48
#include <sys/ioctl.h> /* ioctl */
49
#include <sys/types.h> /* socket(), inet_pton(), sockaddr,
50
sockaddr_in6, PF_INET6,
51
SOCK_STREAM, INET6_ADDRSTRLEN,
52
uid_t, gid_t, open(), opendir(),
54
#include <sys/stat.h> /* open() */
55
#include <sys/socket.h> /* socket(), struct sockaddr_in6,
56
struct in6_addr, inet_pton(),
58
#include <fcntl.h> /* open() */
59
#include <dirent.h> /* opendir(), struct dirent, readdir()
61
#include <inttypes.h> /* PRIu16, intmax_t, SCNdMAX */
62
#include <assert.h> /* assert() */
63
#include <errno.h> /* perror(), errno */
64
#include <time.h> /* nanosleep(), time() */
42
65
#include <net/if.h> /* ioctl, ifreq, SIOCGIFFLAGS, IFF_UP,
66
SIOCSIFFLAGS, if_indextoname(),
67
if_nametoindex(), IF_NAMESIZE */
68
#include <netinet/in.h>
69
#include <unistd.h> /* close(), SEEK_SET, off_t, write(),
70
getuid(), getgid(), setuid(),
72
#include <arpa/inet.h> /* inet_pton(), htons */
73
#include <iso646.h> /* not, and, or */
74
#include <argp.h> /* struct argp_option, error_t, struct
75
argp_state, struct argp,
76
argp_parse(), ARGP_KEY_ARG,
77
ARGP_KEY_END, ARGP_ERR_UNKNOWN */
78
#include <sys/klog.h> /* klogctl() */
81
/* All Avahi types, constants and functions
45
84
#include <avahi-core/core.h>
46
85
#include <avahi-core/lookup.h>
47
86
#include <avahi-core/log.h>
49
88
#include <avahi-common/malloc.h>
50
89
#include <avahi-common/error.h>
52
/* Mandos client part */
53
#include <sys/types.h> /* socket(), inet_pton() */
54
#include <sys/socket.h> /* socket(), struct sockaddr_in6,
55
struct in6_addr, inet_pton() */
56
#include <gnutls/gnutls.h> /* All GnuTLS stuff */
57
#include <gnutls/openpgp.h> /* GnuTLS with openpgp stuff */
59
#include <unistd.h> /* close() */
60
#include <netinet/in.h>
61
#include <stdbool.h> /* true */
62
#include <string.h> /* memset */
63
#include <arpa/inet.h> /* inet_pton() */
64
#include <iso646.h> /* not */
65
#include <net/if.h> /* IF_NAMESIZE */
92
#include <gnutls/gnutls.h> /* All GnuTLS types, constants and
95
init_gnutls_session(),
97
#include <gnutls/openpgp.h>
98
/* gnutls_certificate_set_openpgp_key_file(),
99
GNUTLS_OPENPGP_FMT_BASE64 */
68
#include <errno.h> /* perror() */
102
#include <gpgme.h> /* All GPGME types, constants and
105
GPGME_PROTOCOL_OpenPGP,
74
108
#define BUFFER_SIZE 256
76
static const char *keydir = "/conf/conf.d/mandos";
77
static const char *pubkeyfile = "pubkey.txt";
78
static const char *seckeyfile = "seckey.txt";
110
#define PATHDIR "/conf/conf.d/mandos"
111
#define SECKEY "seckey.txt"
112
#define PUBKEY "pubkey.txt"
80
114
bool debug = false;
115
static const char mandos_protocol_version[] = "1";
116
const char *argp_program_version = "mandos-client " VERSION;
117
const char *argp_program_bug_address = "<mandos@fukt.bsnet.se>";
82
/* Used for passing in values through all the callback functions */
119
/* Used for passing in values through the Avahi callback functions */
84
121
AvahiSimplePoll *simple_poll;
85
122
AvahiServer *server;
86
123
gnutls_certificate_credentials_t cred;
87
124
unsigned int dh_bits;
125
gnutls_dh_params_t dh_params;
88
126
const char *priority;
131
* Make room in "buffer" for at least BUFFER_SIZE additional bytes.
132
* "buffer_capacity" is how much is currently allocated,
133
* "buffer_length" is how much is already used.
135
size_t adjustbuffer(char **buffer, size_t buffer_length,
136
size_t buffer_capacity){
137
if(buffer_length + BUFFER_SIZE > buffer_capacity){
138
*buffer = realloc(*buffer, buffer_capacity + BUFFER_SIZE);
142
buffer_capacity += BUFFER_SIZE;
144
return buffer_capacity;
92
* Decrypt OpenPGP data using keyrings in HOMEDIR.
95
static ssize_t pgp_packet_decrypt (const char *cryptotext,
99
gpgme_data_t dh_crypto, dh_plain;
150
static bool init_gpgme(mandos_context *mc, const char *seckey,
151
const char *pubkey, const char *tempdir){
101
153
gpgme_error_t rc;
103
size_t plaintext_capacity = 0;
104
ssize_t plaintext_length = 0;
105
154
gpgme_engine_info_t engine_info;
108
fprintf(stderr, "Trying to decrypt OpenPGP data\n");
158
* Helper function to insert pub and seckey to the engine keyring.
160
bool import_key(const char *filename){
162
gpgme_data_t pgp_data;
164
fd = (int)TEMP_FAILURE_RETRY(open(filename, O_RDONLY));
170
rc = gpgme_data_new_from_fd(&pgp_data, fd);
171
if(rc != GPG_ERR_NO_ERROR){
172
fprintf(stderr, "bad gpgme_data_new_from_fd: %s: %s\n",
173
gpgme_strsource(rc), gpgme_strerror(rc));
177
rc = gpgme_op_import(mc->ctx, pgp_data);
178
if(rc != GPG_ERR_NO_ERROR){
179
fprintf(stderr, "bad gpgme_op_import: %s: %s\n",
180
gpgme_strsource(rc), gpgme_strerror(rc));
184
ret = (int)TEMP_FAILURE_RETRY(close(fd));
188
gpgme_data_release(pgp_data);
193
fprintf(stderr, "Initialize gpgme\n");
112
197
gpgme_check_version(NULL);
113
198
rc = gpgme_engine_check_version(GPGME_PROTOCOL_OpenPGP);
114
if (rc != GPG_ERR_NO_ERROR){
199
if(rc != GPG_ERR_NO_ERROR){
115
200
fprintf(stderr, "bad gpgme_engine_check_version: %s: %s\n",
116
201
gpgme_strsource(rc), gpgme_strerror(rc));
120
/* Set GPGME home directory for the OpenPGP engine only */
121
rc = gpgme_get_engine_info (&engine_info);
122
if (rc != GPG_ERR_NO_ERROR){
205
/* Set GPGME home directory for the OpenPGP engine only */
206
rc = gpgme_get_engine_info(&engine_info);
207
if(rc != GPG_ERR_NO_ERROR){
123
208
fprintf(stderr, "bad gpgme_get_engine_info: %s: %s\n",
124
209
gpgme_strsource(rc), gpgme_strerror(rc));
127
212
while(engine_info != NULL){
128
213
if(engine_info->protocol == GPGME_PROTOCOL_OpenPGP){
129
214
gpgme_set_engine_info(GPGME_PROTOCOL_OpenPGP,
130
engine_info->file_name, homedir);
215
engine_info->file_name, tempdir);
133
218
engine_info = engine_info->next;
135
220
if(engine_info == NULL){
136
fprintf(stderr, "Could not set GPGME home dir to %s\n", homedir);
221
fprintf(stderr, "Could not set GPGME home dir to %s\n", tempdir);
225
/* Create new GPGME "context" */
226
rc = gpgme_new(&(mc->ctx));
227
if(rc != GPG_ERR_NO_ERROR){
228
fprintf(stderr, "bad gpgme_new: %s: %s\n",
229
gpgme_strsource(rc), gpgme_strerror(rc));
233
if(not import_key(pubkey) or not import_key(seckey)){
241
* Decrypt OpenPGP data.
242
* Returns -1 on error
244
static ssize_t pgp_packet_decrypt(const mandos_context *mc,
245
const char *cryptotext,
248
gpgme_data_t dh_crypto, dh_plain;
251
size_t plaintext_capacity = 0;
252
ssize_t plaintext_length = 0;
255
fprintf(stderr, "Trying to decrypt OpenPGP data\n");
140
258
/* Create new GPGME data buffer from memory cryptotext */
141
259
rc = gpgme_data_new_from_mem(&dh_crypto, cryptotext, crypto_size,
143
if (rc != GPG_ERR_NO_ERROR){
261
if(rc != GPG_ERR_NO_ERROR){
144
262
fprintf(stderr, "bad gpgme_data_new_from_mem: %s: %s\n",
145
263
gpgme_strsource(rc), gpgme_strerror(rc));
149
267
/* Create new empty GPGME data buffer for the plaintext */
150
268
rc = gpgme_data_new(&dh_plain);
151
if (rc != GPG_ERR_NO_ERROR){
269
if(rc != GPG_ERR_NO_ERROR){
152
270
fprintf(stderr, "bad gpgme_data_new: %s: %s\n",
153
271
gpgme_strsource(rc), gpgme_strerror(rc));
154
272
gpgme_data_release(dh_crypto);
158
/* Create new GPGME "context" */
159
rc = gpgme_new(&ctx);
160
if (rc != GPG_ERR_NO_ERROR){
161
fprintf(stderr, "bad gpgme_new: %s: %s\n",
162
gpgme_strsource(rc), gpgme_strerror(rc));
163
plaintext_length = -1;
167
276
/* Decrypt data from the cryptotext data buffer to the plaintext
169
rc = gpgme_op_decrypt(ctx, dh_crypto, dh_plain);
170
if (rc != GPG_ERR_NO_ERROR){
278
rc = gpgme_op_decrypt(mc->ctx, dh_crypto, dh_plain);
279
if(rc != GPG_ERR_NO_ERROR){
171
280
fprintf(stderr, "bad gpgme_op_decrypt: %s: %s\n",
172
281
gpgme_strsource(rc), gpgme_strerror(rc));
173
282
plaintext_length = -1;
284
gpgme_decrypt_result_t result;
285
result = gpgme_op_decrypt_result(mc->ctx);
287
fprintf(stderr, "gpgme_op_decrypt_result failed\n");
289
fprintf(stderr, "Unsupported algorithm: %s\n",
290
result->unsupported_algorithm);
291
fprintf(stderr, "Wrong key usage: %u\n",
292
result->wrong_key_usage);
293
if(result->file_name != NULL){
294
fprintf(stderr, "File name: %s\n", result->file_name);
296
gpgme_recipient_t recipient;
297
recipient = result->recipients;
299
while(recipient != NULL){
300
fprintf(stderr, "Public key algorithm: %s\n",
301
gpgme_pubkey_algo_name(recipient->pubkey_algo));
302
fprintf(stderr, "Key ID: %s\n", recipient->keyid);
303
fprintf(stderr, "Secret key available: %s\n",
304
recipient->status == GPG_ERR_NO_SECKEY
306
recipient = recipient->next;
174
311
goto decrypt_end;
178
315
fprintf(stderr, "Decryption of OpenPGP data succeeded\n");
182
gpgme_decrypt_result_t result;
183
result = gpgme_op_decrypt_result(ctx);
185
fprintf(stderr, "gpgme_op_decrypt_result failed\n");
187
fprintf(stderr, "Unsupported algorithm: %s\n",
188
result->unsupported_algorithm);
189
fprintf(stderr, "Wrong key usage: %d\n",
190
result->wrong_key_usage);
191
if(result->file_name != NULL){
192
fprintf(stderr, "File name: %s\n", result->file_name);
194
gpgme_recipient_t recipient;
195
recipient = result->recipients;
197
while(recipient != NULL){
198
fprintf(stderr, "Public key algorithm: %s\n",
199
gpgme_pubkey_algo_name(recipient->pubkey_algo));
200
fprintf(stderr, "Key ID: %s\n", recipient->keyid);
201
fprintf(stderr, "Secret key available: %s\n",
202
recipient->status == GPG_ERR_NO_SECKEY
204
recipient = recipient->next;
210
318
/* Seek back to the beginning of the GPGME plaintext data buffer */
211
if (gpgme_data_seek(dh_plain, (off_t) 0, SEEK_SET) == -1){
212
perror("pgpme_data_seek");
319
if(gpgme_data_seek(dh_plain, (off_t)0, SEEK_SET) == -1){
320
perror("gpgme_data_seek");
213
321
plaintext_length = -1;
214
322
goto decrypt_end;
217
325
*plaintext = NULL;
219
if (plaintext_length + BUFFER_SIZE
220
> (ssize_t) plaintext_capacity){
221
*plaintext = realloc(*plaintext, plaintext_capacity
223
if (*plaintext == NULL){
327
plaintext_capacity = adjustbuffer(plaintext,
328
(size_t)plaintext_length,
330
if(plaintext_capacity == 0){
331
perror("adjustbuffer");
225
332
plaintext_length = -1;
226
333
goto decrypt_end;
228
plaintext_capacity += BUFFER_SIZE;
231
336
ret = gpgme_data_read(dh_plain, *plaintext + plaintext_length,
233
338
/* Print the data, if any */
300
407
/* OpenPGP credentials */
301
if ((ret = gnutls_certificate_allocate_credentials (&mc->cred))
302
!= GNUTLS_E_SUCCESS) {
303
fprintf (stderr, "GnuTLS memory error: %s\n",
304
safer_gnutls_strerror(ret));
408
gnutls_certificate_allocate_credentials(&mc->cred);
409
if(ret != GNUTLS_E_SUCCESS){
410
fprintf(stderr, "GnuTLS memory error: %s\n", /* Spurious warning
414
safer_gnutls_strerror(ret));
415
gnutls_global_deinit();
309
fprintf(stderr, "Attempting to use OpenPGP certificate %s"
310
" and keyfile %s as GnuTLS credentials\n", pubkeyfile,
420
fprintf(stderr, "Attempting to use OpenPGP public key %s and"
421
" secret key %s as GnuTLS credentials\n", pubkeyfilename,
314
425
ret = gnutls_certificate_set_openpgp_key_file
315
(mc->cred, pubkeyfile, seckeyfile, GNUTLS_OPENPGP_FMT_BASE64);
316
if (ret != GNUTLS_E_SUCCESS) {
426
(mc->cred, pubkeyfilename, seckeyfilename,
427
GNUTLS_OPENPGP_FMT_BASE64);
428
if(ret != GNUTLS_E_SUCCESS) {
318
430
"Error[%d] while reading the OpenPGP key pair ('%s',"
319
" '%s')\n", ret, pubkeyfile, seckeyfile);
320
fprintf(stdout, "The GnuTLS error is: %s\n",
431
" '%s')\n", ret, pubkeyfilename, seckeyfilename);
432
fprintf(stderr, "The GnuTLS error is: %s\n",
321
433
safer_gnutls_strerror(ret));
325
437
/* GnuTLS server initialization */
326
ret = gnutls_dh_params_init(dh_params);
327
if (ret != GNUTLS_E_SUCCESS) {
328
fprintf (stderr, "Error in GnuTLS DH parameter initialization:"
329
" %s\n", safer_gnutls_strerror(ret));
332
ret = gnutls_dh_params_generate2(*dh_params, mc->dh_bits);
333
if (ret != GNUTLS_E_SUCCESS) {
334
fprintf (stderr, "Error in GnuTLS prime generation: %s\n",
335
safer_gnutls_strerror(ret));
339
gnutls_certificate_set_dh_params(mc->cred, *dh_params);
438
ret = gnutls_dh_params_init(&mc->dh_params);
439
if(ret != GNUTLS_E_SUCCESS) {
440
fprintf(stderr, "Error in GnuTLS DH parameter initialization:"
441
" %s\n", safer_gnutls_strerror(ret));
444
ret = gnutls_dh_params_generate2(mc->dh_params, mc->dh_bits);
445
if(ret != GNUTLS_E_SUCCESS) {
446
fprintf(stderr, "Error in GnuTLS prime generation: %s\n",
447
safer_gnutls_strerror(ret));
451
gnutls_certificate_set_dh_params(mc->cred, mc->dh_params);
457
gnutls_certificate_free_credentials(mc->cred);
458
gnutls_global_deinit();
459
gnutls_dh_params_deinit(mc->dh_params);
463
static int init_gnutls_session(mandos_context *mc,
464
gnutls_session_t *session){
341
466
/* GnuTLS session creation */
342
467
ret = gnutls_init(session, GNUTLS_SERVER);
343
if (ret != GNUTLS_E_SUCCESS){
468
if(ret != GNUTLS_E_SUCCESS){
344
469
fprintf(stderr, "Error in GnuTLS session initialization: %s\n",
345
470
safer_gnutls_strerror(ret));
662
/* Combines file name and path and returns the malloced new
663
string. some sane checks could/should be added */
664
static const char *combinepath(const char *first, const char *second){
665
size_t f_len = strlen(first);
666
size_t s_len = strlen(second);
667
char *tmp = malloc(f_len + s_len + 2);
672
memcpy(tmp, first, f_len); /* Spurious warning */
676
memcpy(tmp + f_len + 1, second, s_len); /* Spurious warning */
678
tmp[f_len + 1 + s_len] = '\0';
683
822
int main(int argc, char *argv[]){
684
823
AvahiSServiceBrowser *sb = NULL;
687
828
int exitcode = EXIT_SUCCESS;
688
829
const char *interface = "eth0";
689
830
struct ifreq network;
691
834
char *connect_to = NULL;
835
char tempdir[] = "/tmp/mandosXXXXXX";
836
bool tempdir_created = false;
692
837
AvahiIfIndex if_index = AVAHI_IF_UNSPEC;
838
const char *seckey = PATHDIR "/" SECKEY;
839
const char *pubkey = PATHDIR "/" PUBKEY;
693
841
mandos_context mc = { .simple_poll = NULL, .server = NULL,
694
.dh_bits = 1024, .priority = "SECURE256"};
842
.dh_bits = 1024, .priority = "SECURE256"
843
":!CTYPE-X.509:+CTYPE-OPENPGP" };
844
bool gnutls_initialized = false;
845
bool gpgme_initialized = false;
697
/* Temporary int to get the address of for getopt_long */
698
int debug_int = debug ? 1 : 0;
700
struct option long_options[] = {
701
{"debug", no_argument, &debug_int, 1},
702
{"connect", required_argument, NULL, 'c'},
703
{"interface", required_argument, NULL, 'i'},
704
{"keydir", required_argument, NULL, 'd'},
705
{"seckey", required_argument, NULL, 's'},
706
{"pubkey", required_argument, NULL, 'p'},
707
{"dh-bits", required_argument, NULL, 'D'},
708
{"priority", required_argument, NULL, 'P'},
711
int option_index = 0;
712
ret = getopt_long (argc, argv, "i:", long_options,
739
mc.dh_bits = (unsigned int) strtol(optarg, NULL, 10);
746
mc.priority = optarg;
849
struct argp_option options[] = {
850
{ .name = "debug", .key = 128,
851
.doc = "Debug mode", .group = 3 },
852
{ .name = "connect", .key = 'c',
853
.arg = "ADDRESS:PORT",
854
.doc = "Connect directly to a specific Mandos server",
856
{ .name = "interface", .key = 'i',
858
.doc = "Interface that will be used to search for Mandos"
861
{ .name = "seckey", .key = 's',
863
.doc = "OpenPGP secret key file base name",
865
{ .name = "pubkey", .key = 'p',
867
.doc = "OpenPGP public key file base name",
869
{ .name = "dh-bits", .key = 129,
871
.doc = "Bit length of the prime number used in the"
872
" Diffie-Hellman key exchange",
874
{ .name = "priority", .key = 130,
876
.doc = "GnuTLS priority string for the TLS handshake",
878
{ .name = "delay", .key = 131,
880
.doc = "Maximum delay to wait for interface startup",
885
error_t parse_opt(int key, char *arg,
886
struct argp_state *state) {
888
case 128: /* --debug */
891
case 'c': /* --connect */
894
case 'i': /* --interface */
897
case 's': /* --seckey */
900
case 'p': /* --pubkey */
903
case 129: /* --dh-bits */
904
ret = sscanf(arg, "%" SCNdMAX "%n", &tmpmax, &numchars);
905
if(ret < 1 or tmpmax != (typeof(mc.dh_bits))tmpmax
906
or arg[numchars] != '\0'){
907
fprintf(stderr, "Bad number of DH bits\n");
910
mc.dh_bits = (typeof(mc.dh_bits))tmpmax;
912
case 130: /* --priority */
915
case 131: /* --delay */
916
ret = sscanf(arg, "%lf%n", &delay, &numchars);
917
if(ret < 1 or arg[numchars] != '\0'){
918
fprintf(stderr, "Bad delay\n");
750
/* getopt_long() has already printed a message about the
751
unrcognized option, so just exit. */
755
/* Set the global debug flag from the temporary int */
756
debug = debug_int ? true : false;
759
pubkeyfile = combinepath(keydir, pubkeyfile);
760
if (pubkeyfile == NULL){
761
perror("combinepath");
762
exitcode = EXIT_FAILURE;
766
seckeyfile = combinepath(keydir, seckeyfile);
767
if (seckeyfile == NULL){
768
perror("combinepath");
927
return ARGP_ERR_UNKNOWN;
932
struct argp argp = { .options = options, .parser = parse_opt,
934
.doc = "Mandos client -- Get and decrypt"
935
" passwords from a Mandos server" };
936
ret = argp_parse(&argp, argc, argv, 0, 0, NULL);
937
if(ret == ARGP_ERR_UNKNOWN){
938
fprintf(stderr, "Unknown error while parsing arguments\n");
939
exitcode = EXIT_FAILURE;
944
/* If the interface is down, bring it up */
946
/* Lower kernel loglevel to KERN_NOTICE to avoid KERN_INFO
947
messages to mess up the prompt */
948
ret = klogctl(8, NULL, 5);
953
sd = socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP);
956
exitcode = EXIT_FAILURE;
957
ret = klogctl(7, NULL, 0);
963
strcpy(network.ifr_name, interface);
964
ret = ioctl(sd, SIOCGIFFLAGS, &network);
966
perror("ioctl SIOCGIFFLAGS");
967
ret = klogctl(7, NULL, 0);
971
exitcode = EXIT_FAILURE;
974
if((network.ifr_flags & IFF_UP) == 0){
975
network.ifr_flags |= IFF_UP;
976
ret = ioctl(sd, SIOCSIFFLAGS, &network);
978
perror("ioctl SIOCSIFFLAGS");
979
exitcode = EXIT_FAILURE;
980
ret = klogctl(7, NULL, 0);
987
/* sleep checking until interface is running */
988
for(int i=0; i < delay * 4; i++){
989
ret = ioctl(sd, SIOCGIFFLAGS, &network);
991
perror("ioctl SIOCGIFFLAGS");
992
} else if(network.ifr_flags & IFF_RUNNING){
995
struct timespec sleeptime = { .tv_nsec = 250000000 };
996
nanosleep(&sleeptime, NULL);
998
ret = (int)TEMP_FAILURE_RETRY(close(sd));
1002
/* Restores kernel loglevel to default */
1003
ret = klogctl(7, NULL, 0);
1022
ret = init_gnutls_global(&mc, pubkey, seckey);
1024
fprintf(stderr, "init_gnutls_global failed\n");
1025
exitcode = EXIT_FAILURE;
1028
gnutls_initialized = true;
1031
if(mkdtemp(tempdir) == NULL){
1035
tempdir_created = true;
1037
if(not init_gpgme(&mc, pubkey, seckey, tempdir)){
1038
fprintf(stderr, "init_gpgme failed\n");
1039
exitcode = EXIT_FAILURE;
1042
gpgme_initialized = true;
772
1045
if_index = (AvahiIfIndex) if_nametoindex(interface);
773
1046
if(if_index == 0){
774
1047
fprintf(stderr, "No such interface: \"%s\"\n", interface);
1048
exitcode = EXIT_FAILURE;
778
1052
if(connect_to != NULL){