/* * libwebsockets - small server side websockets and web server implementation * * Copyright (C) 2010 - 2019 Andy Green * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to * deal in the Software without restriction, including without limitation the * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or * sell copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS * IN THE SOFTWARE. */ #include "private-lib-core.h" #define LWSNTPC_LI_NONE 0 #define LWSNTPC_VN_3 3 #define LWSNTPC_MODE_CLIENT 3 struct vhd_ntpc { struct lws_context *context; struct lws_vhost *vhost; const struct lws_protocols *protocol; lws_sorted_usec_list_t sul_conn; lws_sorted_usec_list_t sul_write; /* track write retries */ lws_state_notify_link_t notify_link; const char *ntp_server_ads; struct lws *wsi_udp; uint16_t retry_count_conn; uint16_t retry_count_write; char set_time; }; /* * Without a valid ntp we won't be able to do anything requiring client tls. * * We have our own outer backoff scheme that just keeps retrying dns lookup * and the transaction forever. */ static const uint32_t botable[] = { 1000, 1250, 1500, 2000, 3000 }; static const lws_retry_bo_t bo = { botable, LWS_ARRAY_SIZE(botable), LWS_RETRY_CONCEAL_ALWAYS, 0, 0, 20 }; /* * Once we resolved the remote server (implying we should have network), * we use a different policy on the wsi itself that gives it a few tries before * failing the wsi and using to outer retry policy to get dns to a different * server in the pool and try fresh */ static const uint32_t botable2[] = { 1000, 1250, 5000 /* in case dog slow */ }; static const lws_retry_bo_t bo2 = { botable2, LWS_ARRAY_SIZE(botable2), LWS_ARRAY_SIZE(botable2), /* don't conceal after the last table entry */ 0, 0, 20 }; static void lws_ntpc_retry_conn(struct lws_sorted_usec_list *sul) { struct vhd_ntpc *v = lws_container_of(sul, struct vhd_ntpc, sul_conn); lwsl_debug("%s: wsi_udp: %p\n", __func__, v->wsi_udp); if (v->wsi_udp || !lws_dll2_is_detached(&v->sul_conn.list)) return; /* create the UDP socket aimed at the server */ lwsl_debug("%s: server %s\n", __func__, v->ntp_server_ads); v->retry_count_write = 0; v->wsi_udp = lws_create_adopt_udp(v->vhost, v->ntp_server_ads, 123, 0, v->protocol->name, NULL, NULL, NULL, &bo2); lwsl_debug("%s: created wsi_udp: %p\n", __func__, v->wsi_udp); if (!v->wsi_udp) { lwsl_err("%s: unable to create udp skt\n", __func__); lws_retry_sul_schedule(v->context, 0, &v->sul_conn, &bo, lws_ntpc_retry_conn, &v->retry_count_conn); } } static void lws_ntpc_retry_write(struct lws_sorted_usec_list *sul) { struct vhd_ntpc *v = lws_container_of(sul, struct vhd_ntpc, sul_write); lwsl_debug("%s\n", __func__); if (v && v->wsi_udp) lws_callback_on_writable(v->wsi_udp); } static int lws_sys_ntpc_notify_cb(lws_state_manager_t *mgr, lws_state_notify_link_t *l, int current, int target) { struct vhd_ntpc *v = lws_container_of(l, struct vhd_ntpc, notify_link); if (target != LWS_SYSTATE_TIME_VALID || v->set_time) return 0; /* it's trying to do it ever since the protocol / vhost was set up */ return 1; } static int callback_ntpc(struct lws *wsi, enum lws_callback_reasons reason, void *user, void *in, size_t len) { struct vhd_ntpc *v = (struct vhd_ntpc *) lws_protocol_vh_priv_get(lws_get_vhost(wsi), lws_get_protocol(wsi)); uint8_t pkt[LWS_PRE + 48]; uint64_t ns; switch (reason) { case LWS_CALLBACK_PROTOCOL_INIT: /* per vhost */ if (v) break; lwsl_debug("%s: LWS_CALLBACK_PROTOCOL_INIT:\n", __func__); lws_protocol_vh_priv_zalloc(wsi->vhost, wsi->protocol, sizeof(*v)); v = (struct vhd_ntpc *)lws_protocol_vh_priv_get(wsi->vhost, wsi->protocol); v->context = lws_get_context(wsi); v->vhost = lws_get_vhost(wsi); v->protocol = lws_get_protocol(wsi); if (!lws_system_get_ops(wsi->context) || !lws_system_get_ops(wsi->context)->set_clock) { lwsl_err("%s: set up system ops for set_clock\n", __func__); // return -1; } /* register our lws_system notifier */ v->notify_link.notify_cb = lws_sys_ntpc_notify_cb; v->notify_link.name = "ntpclient"; lws_state_reg_notifier(&wsi->context->mgr_system, &v->notify_link); v->ntp_server_ads = "pool.ntp.org"; lws_system_blob_get_single_ptr(lws_system_get_blob( v->context, LWS_SYSBLOB_TYPE_NTP_SERVER, 0), (const uint8_t **)&v->ntp_server_ads); lws_ntpc_retry_conn(&v->sul_conn); break; case LWS_CALLBACK_PROTOCOL_DESTROY: /* per vhost */ if (!v) break; if (v->wsi_udp) lws_set_timeout(v->wsi_udp, 1, LWS_TO_KILL_ASYNC); lws_state_reg_deregister(&v->notify_link); v->wsi_udp = NULL; goto cancel_conn_timer; /* callbacks related to raw socket descriptor */ case LWS_CALLBACK_RAW_ADOPT: lwsl_debug("%s: LWS_CALLBACK_RAW_ADOPT\n", __func__); lws_callback_on_writable(wsi); break; case LWS_CALLBACK_CLIENT_CONNECTION_ERROR: lwsl_info("%s: CONNECTION_ERROR\n", __func__); goto do_close; case LWS_CALLBACK_RAW_CLOSE: lwsl_debug("%s: LWS_CALLBACK_RAW_CLOSE\n", __func__); do_close: v->wsi_udp = NULL; /* cancel any pending write retry */ lws_sul_schedule(v->context, 0, &v->sul_write, NULL, LWS_SET_TIMER_USEC_CANCEL); if (v->set_time) goto cancel_conn_timer; lws_retry_sul_schedule(v->context, 0, &v->sul_conn, &bo, lws_ntpc_retry_conn, &v->retry_count_conn); break; case LWS_CALLBACK_RAW_RX: if (len != 48) return 0; /* ignore it */ /* * First get the seconds, corrected for the ntp epoch of 1900 * vs the unix epoch of 1970. Then shift the seconds up by 1bn * and add in the ns */ ns = lws_ser_ru32be(((uint8_t *)in) + 40) - 2208988800; ns = (ns * 1000000000) + lws_ser_ru32be(((uint8_t *)in) + 44); lwsl_notice("%s: Unix time: %llu\n", __func__, (unsigned long long)ns / 1000000000); // lws_system_get_ops(wsi->context)->set_clock(ns / 1000); v->set_time = 1; lws_state_transition_steps(&wsi->context->mgr_system, LWS_SYSTATE_OPERATIONAL); /* close the wsi */ return -1; case LWS_CALLBACK_RAW_WRITEABLE: /* * UDP is not reliable, it can be locally dropped, or dropped * by any intermediary or the remote peer. So even though we * will do the write in a moment, we schedule another request * for rewrite according to the wsi retry policy. * * If the result came before, we'll cancel it in the close flow. * * If we have already reached the end of our concealed retries * in the policy, just close without another write. */ if (lws_dll2_is_detached(&v->sul_write.list) && lws_retry_sul_schedule_retry_wsi(wsi, &v->sul_write, lws_ntpc_retry_write, &v->retry_count_write)) { /* we have reached the end of our concealed retries */ lwsl_warn("%s: concealed retries done, failing\n", __func__); goto retry_conn; } memset(pkt + LWS_PRE, 0, sizeof(pkt) - LWS_PRE); pkt[LWS_PRE] = (LWSNTPC_LI_NONE << 6) | (LWSNTPC_VN_3 << 3) | (LWSNTPC_MODE_CLIENT << 0); if (lws_write(wsi, pkt + LWS_PRE, sizeof(pkt) - LWS_PRE, 0) == sizeof(pkt) - LWS_PRE) break; lwsl_err("%s: Failed to write ntp client req\n", __func__); retry_conn: lws_retry_sul_schedule(wsi->context, 0, &v->sul_conn, &bo, lws_ntpc_retry_conn, &v->retry_count_conn); return -1; default: break; } return 0; cancel_conn_timer: lws_sul_schedule(v->context, 0, &v->sul_conn, NULL, LWS_SET_TIMER_USEC_CANCEL); return 0; } struct lws_protocols lws_system_protocol_ntpc = { "lws-ntpclient", callback_ntpc, 0, 128, };