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 31struct 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 52static const uint32_t botable[] = 53 { 300, 500, 650, 800, 800, 900, 1000, 1100, 1500 }; 54static 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 64static const uint32_t botable2[] = { 1000, 1250, 5000 /* in case dog slow */ }; 65static 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 69static void 70lws_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 96static void 97lws_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 107static int 108callback_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__); 181do_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 278retry_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 292cancel_conn_timer: 293 lws_sul_cancel(&v->sul_conn); 294 295 return 0; 296} 297 298void 299lws_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 308struct lws_protocols lws_system_protocol_ntpc = 309 { "lws-ntpclient", callback_ntpc, 0, 128, 0, NULL, 0 }; 310 311