1 /*
2 * libwebsockets - small server side websockets and web server implementation
3 *
4 * Copyright (C) 2010 - 2020 Andy Green <andy@warmcat.com>
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to
8 * deal in the Software without restriction, including without limitation the
9 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
10 * sell copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
22 * IN THE SOFTWARE.
23 */
24
25 #include "private-lib-core.h"
26
27 #define LWSNTPC_LI_NONE 0
28 #define LWSNTPC_VN_3 3
29 #define LWSNTPC_MODE_CLIENT 3
30
31 struct vhd_ntpc {
32 struct lws_context *context;
33 struct lws_vhost *vhost;
34 const struct lws_protocols *protocol;
35 lws_sorted_usec_list_t sul_conn;
36 lws_sorted_usec_list_t sul_write; /* track write retries */
37 const char *ntp_server_ads;
38 struct lws *wsi_udp;
39 uint16_t retry_count_conn;
40 uint16_t retry_count_write;
41
42 char set_time;
43 };
44
45 /*
46 * Without a valid ntp we won't be able to do anything requiring client tls.
47 *
48 * We have our own outer backoff scheme that just keeps retrying dns lookup
49 * and the transaction forever.
50 */
51
52 static const uint32_t botable[] =
53 { 300, 500, 650, 800, 800, 900, 1000, 1100, 1500 };
54 static const lws_retry_bo_t bo = {
55 botable, LWS_ARRAY_SIZE(botable), LWS_RETRY_CONCEAL_ALWAYS, 0, 0, 20 };
56
57 /*
58 * Once we resolved the remote server (implying we should have network),
59 * we use a different policy on the wsi itself that gives it a few tries before
60 * failing the wsi and using to outer retry policy to get dns to a different
61 * server in the pool and try fresh
62 */
63
64 static const uint32_t botable2[] = { 1000, 1250, 5000 /* in case dog slow */ };
65 static const lws_retry_bo_t bo2 = {
66 botable2, LWS_ARRAY_SIZE(botable2), LWS_ARRAY_SIZE(botable2),
67 /* don't conceal after the last table entry */ 0, 0, 20 };
68
69 static void
lws_ntpc_retry_conn(struct lws_sorted_usec_list * sul)70 lws_ntpc_retry_conn(struct lws_sorted_usec_list *sul)
71 {
72 struct vhd_ntpc *v = lws_container_of(sul, struct vhd_ntpc, sul_conn);
73
74 lwsl_debug("%s: wsi_udp: %s\n", __func__, lws_wsi_tag(v->wsi_udp));
75
76 if (v->wsi_udp || !lws_dll2_is_detached(&v->sul_conn.list))
77 return;
78
79 /* create the UDP socket aimed at the server */
80
81 lwsl_notice("%s: server %s\n", __func__, v->ntp_server_ads);
82
83 v->retry_count_write = 0;
84 v->wsi_udp = lws_create_adopt_udp(v->vhost, v->ntp_server_ads, 123, 0,
85 v->protocol->name, NULL, NULL, NULL,
86 &bo2, "ntpclient");
87 lwsl_debug("%s: created wsi_udp: %s\n", __func__, lws_wsi_tag(v->wsi_udp));
88 if (!v->wsi_udp) {
89 lwsl_err("%s: unable to create udp skt\n", __func__);
90
91 lws_retry_sul_schedule(v->context, 0, &v->sul_conn, &bo,
92 lws_ntpc_retry_conn, &v->retry_count_conn);
93 }
94 }
95
96 static void
lws_ntpc_retry_write(struct lws_sorted_usec_list * sul)97 lws_ntpc_retry_write(struct lws_sorted_usec_list *sul)
98 {
99 struct vhd_ntpc *v = lws_container_of(sul, struct vhd_ntpc, sul_write);
100
101 lwsl_debug("%s\n", __func__);
102
103 if (v && v->wsi_udp)
104 lws_callback_on_writable(v->wsi_udp);
105 }
106
107 static int
callback_ntpc(struct lws * wsi,enum lws_callback_reasons reason,void * user,void * in,size_t len)108 callback_ntpc(struct lws *wsi, enum lws_callback_reasons reason, void *user,
109 void *in, size_t len)
110 {
111 struct vhd_ntpc *v = (struct vhd_ntpc *)
112 lws_protocol_vh_priv_get(lws_get_vhost(wsi),
113 lws_get_protocol(wsi));
114 uint8_t pkt[LWS_PRE + 48];
115 struct timeval t1;
116 int64_t delta_us;
117 uint64_t ns;
118
119 switch (reason) {
120
121 case LWS_CALLBACK_PROTOCOL_INIT: /* per vhost */
122 if (v)
123 break;
124
125 lwsl_debug("%s: LWS_CALLBACK_PROTOCOL_INIT:\n", __func__);
126 lws_protocol_vh_priv_zalloc(wsi->a.vhost, wsi->a.protocol,
127 sizeof(*v));
128 v = (struct vhd_ntpc *)lws_protocol_vh_priv_get(wsi->a.vhost,
129 wsi->a.protocol);
130 v->context = lws_get_context(wsi);
131 v->vhost = lws_get_vhost(wsi);
132 v->protocol = lws_get_protocol(wsi);
133
134 v->context->ntpclient_priv = v;
135
136 if (!lws_system_get_ops(wsi->a.context) ||
137 !lws_system_get_ops(wsi->a.context)->set_clock) {
138 #if !defined(LWS_ESP_PLATFORM)
139 lwsl_err("%s: set up system ops for set_clock\n",
140 __func__);
141 #endif
142
143 // return -1;
144 }
145
146 /* register our lws_system notifier */
147
148 v->ntp_server_ads = "pool.ntp.org";
149 lws_plat_ntpclient_config(v->context);
150 lws_system_blob_get_single_ptr(lws_system_get_blob(
151 v->context, LWS_SYSBLOB_TYPE_NTP_SERVER, 0),
152 (const uint8_t **)&v->ntp_server_ads);
153 if (!v->ntp_server_ads || v->ntp_server_ads[0] == '\0')
154 v->ntp_server_ads = "pool.ntp.org";
155
156 lwsl_notice("%s: using ntp server %s\n", __func__,
157 v->ntp_server_ads);
158 break;
159
160 case LWS_CALLBACK_PROTOCOL_DESTROY: /* per vhost */
161 if (!v)
162 break;
163 if (v->wsi_udp)
164 lws_set_timeout(v->wsi_udp, 1, LWS_TO_KILL_ASYNC);
165 v->wsi_udp = NULL;
166 goto cancel_conn_timer;
167
168 /* callbacks related to raw socket descriptor */
169
170 case LWS_CALLBACK_RAW_ADOPT:
171 lwsl_debug("%s: LWS_CALLBACK_RAW_ADOPT\n", __func__);
172 lws_callback_on_writable(wsi);
173 break;
174
175 case LWS_CALLBACK_CLIENT_CONNECTION_ERROR:
176 lwsl_info("%s: CONNECTION_ERROR\n", __func__);
177 goto do_close;
178
179 case LWS_CALLBACK_RAW_CLOSE:
180 lwsl_debug("%s: LWS_CALLBACK_RAW_CLOSE\n", __func__);
181 do_close:
182 v->wsi_udp = NULL;
183
184 /* cancel any pending write retry */
185 lws_sul_cancel(&v->sul_write);
186
187 if (v->set_time)
188 goto cancel_conn_timer;
189
190 lws_retry_sul_schedule(v->context, 0, &v->sul_conn, &bo,
191 lws_ntpc_retry_conn,
192 &v->retry_count_conn);
193 break;
194
195 case LWS_CALLBACK_RAW_RX:
196
197 if (len != 48)
198 return 0; /* ignore it */
199
200 /*
201 * First get the seconds, corrected for the ntp epoch of 1900
202 * vs the unix epoch of 1970. Then shift the seconds up by 1bn
203 * and add in the ns
204 */
205
206 ns = (uint64_t)lws_ser_ru32be(((uint8_t *)in) + 40) - (uint64_t)2208988800;
207 ns = (ns * 1000000000) + lws_ser_ru32be(((uint8_t *)in) + 44);
208
209 /*
210 * Compute the step
211 */
212
213 gettimeofday(&t1, NULL);
214
215 delta_us = ((int64_t)ns / 1000) -
216 ((t1.tv_sec * LWS_US_PER_SEC) + t1.tv_usec);
217
218 lwsl_notice("%s: Unix time: %llu, step: %lldus\n", __func__,
219 (unsigned long long)ns / 1000000000,
220 (long long)delta_us);
221
222 #if defined(LWS_PLAT_FREERTOS)
223 {
224 struct timeval t;
225
226 t.tv_sec = (unsigned long long)ns / 1000000000;
227 t.tv_usec = (ns % 1000000000) / 1000;
228
229 lws_sul_nonmonotonic_adjust(wsi->a.context, delta_us);
230
231 settimeofday(&t, NULL);
232 }
233 #endif
234 if (lws_system_get_ops(wsi->a.context) &&
235 lws_system_get_ops(wsi->a.context)->set_clock)
236 lws_system_get_ops(wsi->a.context)->set_clock((int64_t)ns / 1000);
237
238 v->set_time = 1;
239 lws_state_transition_steps(&wsi->a.context->mgr_system,
240 LWS_SYSTATE_OPERATIONAL);
241
242 /* close the wsi */
243 return -1;
244
245 case LWS_CALLBACK_RAW_WRITEABLE:
246
247 /*
248 * UDP is not reliable, it can be locally dropped, or dropped
249 * by any intermediary or the remote peer. So even though we
250 * will do the write in a moment, we schedule another request
251 * for rewrite according to the wsi retry policy.
252 *
253 * If the result came before, we'll cancel it in the close flow.
254 *
255 * If we have already reached the end of our concealed retries
256 * in the policy, just close without another write.
257 */
258 if (lws_dll2_is_detached(&v->sul_write.list) &&
259 lws_retry_sul_schedule_retry_wsi(wsi, &v->sul_write,
260 lws_ntpc_retry_write,
261 &v->retry_count_write)) {
262 /* we have reached the end of our concealed retries */
263 lwsl_warn("%s: concealed retries done, failing\n", __func__);
264 goto retry_conn;
265 }
266
267 memset(pkt + LWS_PRE, 0, sizeof(pkt) - LWS_PRE);
268 pkt[LWS_PRE] = (LWSNTPC_LI_NONE << 6) |
269 (LWSNTPC_VN_3 << 3) |
270 (LWSNTPC_MODE_CLIENT << 0);
271
272 if (lws_write(wsi, pkt + LWS_PRE, sizeof(pkt) - LWS_PRE, 0) ==
273 sizeof(pkt) - LWS_PRE)
274 break;
275
276 lwsl_err("%s: Failed to write ntp client req\n", __func__);
277
278 retry_conn:
279 lws_retry_sul_schedule(wsi->a.context, 0, &v->sul_conn, &bo,
280 lws_ntpc_retry_conn,
281 &v->retry_count_conn);
282
283 return -1;
284
285 default:
286 break;
287 }
288
289 return 0;
290
291
292 cancel_conn_timer:
293 lws_sul_cancel(&v->sul_conn);
294
295 return 0;
296 }
297
298 void
lws_ntpc_trigger(struct lws_context * ctx)299 lws_ntpc_trigger(struct lws_context *ctx)
300 {
301 struct vhd_ntpc *v = (struct vhd_ntpc *)ctx->ntpclient_priv;
302
303 lwsl_notice("%s\n", __func__);
304 v->retry_count_conn = 0;
305 lws_ntpc_retry_conn(&v->sul_conn);
306 }
307
308 struct lws_protocols lws_system_protocol_ntpc =
309 { "lws-ntpclient", callback_ntpc, 0, 128, 0, NULL, 0 };
310
311