1 /*
2 * lws-minimal-ws-client
3 *
4 * Written in 2010-2020 by Andy Green <andy@warmcat.com>
5 *
6 * This file is made available under the Creative Commons CC0 1.0
7 * Universal Public Domain Dedication.
8 *
9 * This demonstrates a ws client that connects by default to libwebsockets.org
10 * dumb increment ws server.
11 */
12
13 #include <libwebsockets.h>
14 #include <string.h>
15 #include <signal.h>
16 #include <pthread.h>
17
18 /*
19 * This represents your object that "contains" the client connection and has
20 * the client connection bound to it
21 */
22
23 static struct my_conn {
24 lws_sorted_usec_list_t sul; /* schedule connection retry */
25 struct lws *wsi; /* related wsi if any */
26 uint16_t retry_count; /* count of consequetive retries */
27 } mco;
28
29 static struct lws_context *context;
30 static int interrupted, port = 443, ssl_connection = LCCSCF_USE_SSL;
31 static const char *server_address = "libwebsockets.org",
32 *pro = "dumb-increment-protocol";
33
34 /*
35 * The retry and backoff policy we want to use for our client connections
36 */
37
38 static const uint32_t backoff_ms[] = { 1000, 2000, 3000, 4000, 5000 };
39
40 static const lws_retry_bo_t retry = {
41 .retry_ms_table = backoff_ms,
42 .retry_ms_table_count = LWS_ARRAY_SIZE(backoff_ms),
43 .conceal_count = LWS_ARRAY_SIZE(backoff_ms),
44
45 .secs_since_valid_ping = 3, /* force PINGs after secs idle */
46 .secs_since_valid_hangup = 10, /* hangup after secs idle */
47
48 .jitter_percent = 20,
49 };
50
51 /*
52 * Scheduled sul callback that starts the connection attempt
53 */
54
55 static void
connect_client(lws_sorted_usec_list_t * sul)56 connect_client(lws_sorted_usec_list_t *sul)
57 {
58 struct my_conn *mco = lws_container_of(sul, struct my_conn, sul);
59 struct lws_client_connect_info i;
60
61 memset(&i, 0, sizeof(i));
62
63 i.context = context;
64 i.port = port;
65 i.address = server_address;
66 i.path = "/";
67 i.host = i.address;
68 i.origin = i.address;
69 i.ssl_connection = ssl_connection;
70 i.protocol = pro;
71 i.local_protocol_name = "lws-minimal-client";
72 i.pwsi = &mco->wsi;
73 i.retry_and_idle_policy = &retry;
74 i.userdata = mco;
75
76 if (!lws_client_connect_via_info(&i))
77 /*
78 * Failed... schedule a retry... we can't use the _retry_wsi()
79 * convenience wrapper api here because no valid wsi at this
80 * point.
81 */
82 if (lws_retry_sul_schedule(context, 0, sul, &retry,
83 connect_client, &mco->retry_count)) {
84 lwsl_err("%s: connection attempts exhausted\n", __func__);
85 interrupted = 1;
86 }
87 }
88
89 static int
callback_minimal(struct lws * wsi,enum lws_callback_reasons reason,void * user,void * in,size_t len)90 callback_minimal(struct lws *wsi, enum lws_callback_reasons reason,
91 void *user, void *in, size_t len)
92 {
93 struct my_conn *mco = (struct my_conn *)user;
94
95 switch (reason) {
96
97 case LWS_CALLBACK_CLIENT_CONNECTION_ERROR:
98 lwsl_err("CLIENT_CONNECTION_ERROR: %s\n",
99 in ? (char *)in : "(null)");
100 goto do_retry;
101 break;
102
103 case LWS_CALLBACK_CLIENT_RECEIVE:
104 lwsl_hexdump_notice(in, len);
105 break;
106
107 case LWS_CALLBACK_CLIENT_ESTABLISHED:
108 lwsl_user("%s: established\n", __func__);
109 break;
110
111 case LWS_CALLBACK_CLIENT_CLOSED:
112 goto do_retry;
113
114 default:
115 break;
116 }
117
118 return lws_callback_http_dummy(wsi, reason, user, in, len);
119
120 do_retry:
121 /*
122 * retry the connection to keep it nailed up
123 *
124 * For this example, we try to conceal any problem for one set of
125 * backoff retries and then exit the app.
126 *
127 * If you set retry.conceal_count to be larger than the number of
128 * elements in the backoff table, it will never give up and keep
129 * retrying at the last backoff delay plus the random jitter amount.
130 */
131 if (lws_retry_sul_schedule_retry_wsi(wsi, &mco->sul, connect_client,
132 &mco->retry_count)) {
133 lwsl_err("%s: connection attempts exhausted\n", __func__);
134 interrupted = 1;
135 }
136
137 return 0;
138 }
139
140 static const struct lws_protocols protocols[] = {
141 { "lws-minimal-client", callback_minimal, 0, 0, },
142 { NULL, NULL, 0, 0 }
143 };
144
145 static void
sigint_handler(int sig)146 sigint_handler(int sig)
147 {
148 interrupted = 1;
149 }
150
main(int argc,const char ** argv)151 int main(int argc, const char **argv)
152 {
153 struct lws_context_creation_info info;
154 const char *p;
155 int n = 0;
156
157 signal(SIGINT, sigint_handler);
158 memset(&info, 0, sizeof info);
159 lws_cmdline_option_handle_builtin(argc, argv, &info);
160
161 lwsl_user("LWS minimal ws client\n");
162
163 info.options = LWS_SERVER_OPTION_DO_SSL_GLOBAL_INIT;
164 info.port = CONTEXT_PORT_NO_LISTEN; /* we do not run any server */
165 info.protocols = protocols;
166
167 #if defined(LWS_WITH_MBEDTLS)
168 /*
169 * OpenSSL uses the system trust store. mbedTLS has to be told which
170 * CA to trust explicitly.
171 */
172 info.client_ssl_ca_filepath = "./libwebsockets.org.cer";
173 #endif
174
175 if ((p = lws_cmdline_option(argc, argv, "--protocol")))
176 pro = p;
177
178 if ((p = lws_cmdline_option(argc, argv, "-s")))
179 server_address = p;
180
181 if ((p = lws_cmdline_option(argc, argv, "-p")))
182 port = atoi(p);
183
184 if (lws_cmdline_option(argc, argv, "-j"))
185 ssl_connection |= LCCSCF_ALLOW_SELFSIGNED;
186
187 if (lws_cmdline_option(argc, argv, "-k"))
188 ssl_connection |= LCCSCF_ALLOW_INSECURE;
189
190 if (lws_cmdline_option(argc, argv, "-m"))
191 ssl_connection |= LCCSCF_SKIP_SERVER_CERT_HOSTNAME_CHECK;
192
193 if (lws_cmdline_option(argc, argv, "-e"))
194 ssl_connection |= LCCSCF_ALLOW_EXPIRED;
195
196 info.fd_limit_per_thread = 1 + 1 + 1;
197
198 context = lws_create_context(&info);
199 if (!context) {
200 lwsl_err("lws init failed\n");
201 return 1;
202 }
203
204 /* schedule the first client connection attempt to happen immediately */
205 lws_sul_schedule(context, 0, &mco.sul, connect_client, 1);
206
207 while (n >= 0 && !interrupted)
208 n = lws_service(context, 0);
209
210 lws_context_destroy(context);
211 lwsl_user("Completed\n");
212
213 return 0;
214 }
215