GB28181协议--校时

article/2025/9/19 15:47:14

1、简介

根据《GB/T 28181 —2016》7.10、9.10的要求，GB28181设备网络校时功能描述如下：
联网系统内的IP 网络服务器设备宜支持 NTP(见IETF RFC2030) 协议的网络统一校时服务。网络校时设备分为时钟源和客户端, 支持客户/服务器的工作模式; 时钟源应支持 TCP/IP、UDP 及 NTP协议, 能将输入的或自身产生的时间信号以标准的 NTP 信息包格式输出。联网系统内的IP 网络接入设备应支持SIP 信令的统一校时, 接入设备应在注册时接受来自SIP 服务器通过消息头 Date 域携带的授时。

2、基本流程

联网内设备支持基于SIP 方式或 NTP 方式的网络校时功能, 标准时间为北京时间。流程如下所示：
在这里插入图片描述
在注册成功情况下, 注册流程的最后一个 SIP 应答消息200 OK 中的 Date 头域中携带时间信息。采用的格式为 XML 标准格式:Date: yyyy-MM-dd’T’HH: mm:ss.SSS。
若SIP 代理通过注册方式校时, 其注册过期时间宜设置为小于 SIP 代理与 SIP 服务器出现1 s 误差所经过的运行时间。例如:SIP 代理与SIP 服务器校时后,SIP 代理运行10 h 后设备时间与SIP 服务器时间相差大于1 s, 则宜将注册过期时间设置为10 h(36 000s) , 以保证SIP 代理与SIP 服务器之间时间误差小于1 s。

3、基于SIP的校时

sip信令处理：

int SipReg(GB28181Param_t *pGB28181Param, int isReg)
{int ret = 0;int len = 0;char *msg;int expires = 0 ;int regState = 0;int unAuthorized = 0;eXosip_event_t *je = NULL;osip_header_t *dest = NULL;osip_message_t *reg = NULL;long interval = GetSysSec();if (!pGB28181Param){return SIP_FAILED;}if (isReg){expires = strtoul(pGB28181Param->userParam.sipExpires, 0, 0);}while(GetSysSec() -interval <= MAX_SIP_REG_TIMEOUT_SEC){// 先进行不认证注册if (0 == unAuthorized){ret = SipRegisterUnauthorized(pGB28181Param, expires);if (ret < 0){if(je){eXosip_event_free(je);}return SIP_FAILED;}else {unAuthorized = 1;}}je = eXosip_event_wait(0, 100);  		/* 等待新消息的到来 */if(NULL == je){/* 以下语句会导致eXosip_register_send_register失败 */eXosip_automatic_action();usleep(100*1000);continue;}/* 返回注册失败 */if(EXOSIP_REGISTRATION_FAILURE == je->type){/* 未认证注册失败，那么使用认证的方式进行注册 */if((je->response!=NULL) && (401==je->response->status_code)){ret = SipRegisterAuthorized(pGB28181Param, je->rid, expires);eXosip_event_free(je);if(ret != OSIP_SUCCESS){return SIP_FAILED;}}else {eXosip_event_free(je);unAuthorized = 0;			/* 注册失败， 重新走一遍注册流程 */if (isReg){return SIP_REREG_AFTER_60S;}return SIP_FAILED;}}else if (EXOSIP_REGISTRATION_SUCCESS == je->type){regState = 1;/* 收到服务器返回的注册成功 */g_SipState.registerID = je->rid;	if (MSG_IS_REGISTER(je->request) && je->response){if (OSIP_SUCCESS == osip_message_to_str(je->response, &msg, &len)){if (osip_message_get_date(je->response, 0, &dest) > 0){SipSetSystemTime(dest->hvalue);}}}eXosip_execute();eXosip_automatic_action();eXosip_event_free(je);break;}else{eXosip_event_free(je);}}if( (GetSysSec() -interval > MAX_SIP_REG_TIMEOUT_SEC) && (regState == 0)){return SIP_FAILED;}pthread_mutex_lock(&g_SipState.mutex);// 更新sip的注册状态if (isReg){g_SipState.sipRegStatus = 1;g_SipState.keepliveAckTime = GetSysSec();}else {g_SipState.sipRegStatus = 0;}pthread_mutex_unlock(&g_SipState.mutex);return SIP_SUCCESS;
}

设置系统时间接口：

static int SipSetSystemTime(char *timeStr)
{char *beginStr = timeStr;char *endStr = NULL;char tempStr[10] = {0, };struct tm st_time = {0, };struct timeval tv = {0, };uint32_t stime = 0;if (!timeStr){return SIP_FAILED;}if ((endStr = strstr(beginStr, "-"))){memset(tempStr, 0, sizeof(tempStr));strncpy(tempStr, beginStr, endStr-beginStr);beginStr = endStr + 1;stime = strtoul(tempStr, NULL, sizeof(tempStr));st_time.tm_year = stime - 1900;}if ((endStr = strstr(beginStr, "-"))){memset(tempStr, 0, sizeof(tempStr));strncpy(tempStr, beginStr, endStr-beginStr);beginStr = endStr + 1;stime = strtoul(tempStr, NULL, sizeof(tempStr));st_time.tm_mon = stime - 1;}if ((endStr = strstr(beginStr, "T"))){memset(tempStr, 0, sizeof(tempStr));strncpy(tempStr, beginStr, endStr-beginStr);beginStr = endStr + 1;stime = strtoul(tempStr, NULL, sizeof(tempStr));st_time.tm_mday = stime;}if ((endStr = strstr(beginStr, ":"))){memset(tempStr, 0, sizeof(tempStr));strncpy(tempStr, beginStr, endStr-beginStr);beginStr = endStr + 1;stime = strtoul(tempStr, NULL, sizeof(tempStr));st_time.tm_hour = stime;}if ((endStr = strstr(beginStr, ":"))){memset(tempStr, 0, sizeof(tempStr));strncpy(tempStr, beginStr, endStr-beginStr);beginStr = endStr + 1;stime = strtoul(tempStr, NULL, sizeof(tempStr));st_time.tm_min = stime;}if ((endStr = strstr(beginStr, "."))){memset(tempStr, 0, sizeof(tempStr));strncpy(tempStr, beginStr, endStr-beginStr);beginStr = endStr + 1;stime = strtoul(tempStr, NULL, sizeof(tempStr));st_time.tm_sec = stime;}// 设置系统时间if ((tv.tv_sec = mktime(&st_time)) < 0){GB_PrintError("mktime failed\n");return SIP_FAILED;}settimeofday(&tv, NULL);// 设置RTC时间struct tm *stTime = gmtime(&tv);if (SetRtcTime(stTime) < 0){return SIP_FAILED;		}return SIP_SUCCESS;
}