1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
|
/* This example code is placed in the public domain. */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <string.h>
#include <unistd.h>
#include <gnutls/gnutls.h>
#if GNUTLS_VERSION_NUMBER < 0x030300
# define DEFAULT_PRIORITY "NORMAL"
#endif
#define KEYFILE "key.pem"
#define CERTFILE "cert.pem"
#define CAFILE "/etc/ssl/certs/ca-certificates.crt"
#define CRLFILE "crl.pem"
/* This is a sample TLS echo server, supporting X.509 and PSK
authentication.
*/
#define SOCKET_ERR(err,s) if(err==-1) {perror(s);return(1);}
#define MAX_BUF 1024
#define PORT 5556 /* listen to 5556 port */
#define DH_BITS 1024
/* These are global */
static gnutls_dh_params_t dh_params;
static int generate_dh_params(void)
{
/* Generate Diffie-Hellman parameters - for use with DHE
* kx algorithms. When short bit length is used, it might
* be wise to regenerate parameters.
*
* Check the ex-serv-export.c example for using static
* parameters.
*/
gnutls_dh_params_init(&dh_params);
gnutls_dh_params_generate2(dh_params, DH_BITS);
return 0;
}
static int
pskfunc(gnutls_session_t session, const char *username,
gnutls_datum_t * key)
{
printf("psk: username %s\n", username);
key->data = gnutls_malloc(4);
key->data[0] = 0xDE;
key->data[1] = 0xAD;
key->data[2] = 0xBE;
key->data[3] = 0xEF;
key->size = 4;
return 0;
}
int main(void)
{
int err, listen_sd;
int sd, ret;
struct sockaddr_in sa_serv;
struct sockaddr_in sa_cli;
socklen_t client_len;
char topbuf[512];
gnutls_session_t session;
gnutls_certificate_credentials_t x509_cred;
gnutls_psk_server_credentials_t psk_cred;
gnutls_priority_t priority_cache;
char buffer[MAX_BUF + 1];
int optval = 1;
int kx;
if (gnutls_check_version("3.1.4") == NULL) {
fprintf(stderr, "GnuTLS 3.1.4 is required for this example\n");
exit(1);
}
gnutls_global_init();
gnutls_certificate_allocate_credentials(&x509_cred);
gnutls_certificate_set_x509_trust_file(x509_cred, CAFILE,
GNUTLS_X509_FMT_PEM);
gnutls_certificate_set_x509_crl_file(x509_cred, CRLFILE,
GNUTLS_X509_FMT_PEM);
gnutls_certificate_set_x509_key_file(x509_cred, CERTFILE, KEYFILE,
GNUTLS_X509_FMT_PEM);
gnutls_psk_allocate_server_credentials(&psk_cred);
gnutls_psk_set_server_credentials_function(psk_cred, pskfunc);
generate_dh_params();
gnutls_priority_init(&priority_cache,
GNUTLS_DEFAULT_PRIORITY
":+PSK:+ECDHE-PSK:+DHE-PSK",
NULL);
gnutls_certificate_set_dh_params(x509_cred, dh_params);
/* Socket operations
*/
listen_sd = socket(AF_INET, SOCK_STREAM, 0);
SOCKET_ERR(listen_sd, "socket");
memset(&sa_serv, '\0', sizeof(sa_serv));
sa_serv.sin_family = AF_INET;
sa_serv.sin_addr.s_addr = INADDR_ANY;
sa_serv.sin_port = htons(PORT); /* Server Port number */
setsockopt(listen_sd, SOL_SOCKET, SO_REUSEADDR, (void *) &optval,
sizeof(int));
err =
bind(listen_sd, (struct sockaddr *) &sa_serv, sizeof(sa_serv));
SOCKET_ERR(err, "bind");
err = listen(listen_sd, 1024);
SOCKET_ERR(err, "listen");
printf("Server ready. Listening to port '%d'.\n\n", PORT);
client_len = sizeof(sa_cli);
for (;;) {
gnutls_init(&session, GNUTLS_SERVER);
gnutls_priority_set(session, priority_cache);
gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE,
x509_cred);
gnutls_credentials_set(session, GNUTLS_CRD_PSK, psk_cred);
/* request client certificate if any.
*/
gnutls_certificate_server_set_request(session,
GNUTLS_CERT_REQUEST);
sd = accept(listen_sd, (struct sockaddr *) &sa_cli,
&client_len);
printf("- connection from %s, port %d\n",
inet_ntop(AF_INET, &sa_cli.sin_addr, topbuf,
sizeof(topbuf)), ntohs(sa_cli.sin_port));
gnutls_transport_set_int(session, sd);
ret = gnutls_handshake(session);
if (ret < 0) {
close(sd);
gnutls_deinit(session);
fprintf(stderr,
"*** Handshake has failed (%s)\n\n",
gnutls_strerror(ret));
continue;
}
printf("- Handshake was completed\n");
kx = gnutls_kx_get(session);
if (kx == GNUTLS_KX_PSK || kx == GNUTLS_KX_DHE_PSK ||
kx == GNUTLS_KX_ECDHE_PSK) {
printf("- User %s was connected\n",
gnutls_psk_server_get_username(session));
}
/* see the Getting peer's information example */
/* print_info(session); */
for (;;) {
ret = gnutls_record_recv(session, buffer, MAX_BUF);
if (ret == 0) {
printf
("\n- Peer has closed the GnuTLS connection\n");
break;
} else if (ret < 0
&& gnutls_error_is_fatal(ret) == 0) {
fprintf(stderr, "*** Warning: %s\n",
gnutls_strerror(ret));
} else if (ret < 0) {
fprintf(stderr, "\n*** Received corrupted "
"data(%d). Closing the connection.\n\n",
ret);
break;
} else if (ret > 0) {
/* echo data back to the client
*/
gnutls_record_send(session, buffer, ret);
}
}
printf("\n");
/* do not wait for the peer to close the connection.
*/
gnutls_bye(session, GNUTLS_SHUT_WR);
close(sd);
gnutls_deinit(session);
}
close(listen_sd);
gnutls_certificate_free_credentials(x509_cred);
gnutls_psk_free_server_credentials(psk_cred);
gnutls_priority_deinit(priority_cache);
gnutls_global_deinit();
return 0;
}
|
