本篇使用的是lwip編寫udp服務端。需要提前準備好一個PARAM_HOTSPOT_SSID宏定義的熱點，并且密碼為PARAM_HOTSPOT_PSK。

修改網絡參數

在Hi3861開發板上運行上述四個測試程序之前，需要根據你的無線路由、Linux系統IP修改 net_params.h文件的相關代碼：

• PARAM_HOTSPOT_SSID 修改為你的熱點名稱
• PARAM_HOTSPOT_PSK 修改為你的熱點密碼；
• PARAM_SERVER_PORT 修改為你的udp服務器端口號；

LwIP Socket API編程udp服務端主要步驟

創建Socket socket()

設置服務器地址和端口 sockaddr_in

綁定Socket bind()

發送和接收數據 sendto() recv() recvfrom()

關閉Socket close()

代碼編寫

修改D:\DevEcoProjects\test\src\vendor\rtplay\rt_hi3861\demo\BUILD.gn文件

# Copyright (c) 2023 Beijing HuaQing YuanJian Education Technology Co., Ltd
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
# 
#    http://www.apache.org/licenses/LICENSE-2.0
# 
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License. import("//build/lite/config/component/lite_component.gni")lite_component("demo") {features = [#"base_00_helloworld:base_helloworld_example",#"base_01_led:base_led_example",#"base_02_loopkey:base_loopkey_example",#"base_03_irqkey:base_irqkey_example",#"base_04_adc:base_adc_example",#"base_05_pwm:base_pwm_example",#"base_06_ssd1306:base_ssd1306_example",#"kernel_01_task:kernel_task_example",#"kernel_02_timer:kernel_timer_example",#"kernel_03_event:kernel_event_example",#"kernel_04_mutex:kernel_mutex_example",#"kernel_05_semaphore_as_mutex:kernel_semaphore_as_mutex_example",#"kernel_06_semaphore_for_sync:kernel_semaphore_for_sync_example",#"kernel_07_semaphore_for_count:kernel_semaphore_for_count_example",#"kernel_08_message_queue:kernel_message_queue_example",#"wifi_09_hotspot:wifi_hotspot_example",#"wifi_10_sta:wifi_sta_example",#"tcp_11_server:tcp_server_example",#"tcp_12_client:tcp_client_example","udp_13_server:udp_server_example",]
}

創建D:\DevEcoProjects\test\src\vendor\rtplay\rt_hi3861\demo\udp_13_server文件夾

文件夾中創建D:\DevEcoProjects\test\src\vendor\rtplay\rt_hi3861\demo\udp_13_server\BUILD.gn文件

#Copyright (C) 2021 HiHope Open Source Organization .
#Licensed under the Apache License, Version 2.0 (the "License");
#you may not use this file except in compliance with the License.
#You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
#Unless required by applicable law or agreed to in writing, software
#distributed under the License is distributed on an "AS IS" BASIS,
#WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#See the License for the specific language governing permissions and
#
#limitations under the License.static_library("udp_server_example") {# uncomment one of following line, to enable one test:sources = ["udp_server_example.c"]sources += ["wifi_connecter.c"]include_dirs = ["//utils/native/lite/include","//kernel/liteos_m/kal","//foundation/communication/wifi_lite/interfaces/wifiservice",]
}

文件夾中創建D:\DevEcoProjects\test\src\vendor\rtplay\rt_hi3861\demo\udp_13_server\net_common.h文件，文件主要引入一些頭文件。文件同tcp_11_server\net_common.h

文件夾中創建D:\DevEcoProjects\test\src\vendor\rtplay\rt_hi3861\demo\udp_13_server\wifi_connecter.h文件，該頭文件包含wifi連接的宏。文件同tcp_11_server\wifi_connecter.h

文件夾中創建D:\DevEcoProjects\test\src\vendor\rtplay\rt_hi3861\demo\udp_13_server\wifi_connecter.c文件，文件同tcp_11_server\wifi_connecter.c

文件夾中創建D:\DevEcoProjects\test\src\vendor\rtplay\rt_hi3861\demo\udp_13_server\udp_server_example.c文件

/** Copyright (C) 2021 HiHope Open Source Organization .* Licensed under the Apache License, Version 2.0 (the "License");* you may not use this file except in compliance with the License.* You may obtain a copy of the License at**     http://www.apache.org/licenses/LICENSE-2.0** Unless required by applicable law or agreed to in writing, software* distributed under the License is distributed on an "AS IS" BASIS,* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.* See the License for the specific language governing permissions and** limitations under the License.*/#include <errno.h>
#include <stdio.h>
#include <string.h>
// #include <stddef.h>
#include <unistd.h>
#include "ohos_init.h"
#include "cmsis_os2.h"#include "net_common.h"
#include "wifi_connecter.h"#define DELAY_TICKS_10     (10)static char message[128] = "";void UdpServerTest(void)
{WifiDeviceConfig config = {0};// 準備AP的配置參數// strcpy(config.ssid, PARAM_HOTSPOT_SSID);// strcpy(config.preSharedKey, PARAM_HOTSPOT_PSK);strcpy_s(config.ssid, WIFI_MAX_SSID_LEN, PARAM_HOTSPOT_SSID);strcpy_s(config.preSharedKey, WIFI_MAX_KEY_LEN, PARAM_HOTSPOT_PSK);config.securityType = PARAM_HOTSPOT_TYPE;osDelay(DELAY_TICKS_10);int netId = ConnectToHotspot(&config);ssize_t retval = 0;int sockfd = socket(AF_INET, SOCK_DGRAM, 0); // UDP socketstruct sockaddr_in clientAddr = {0};socklen_t clientAddrLen = sizeof(clientAddr);struct sockaddr_in serverAddr = {0};serverAddr.sin_family = AF_INET;serverAddr.sin_port = htons(PARAM_SERVER_PORT);serverAddr.sin_addr.s_addr = htonl(INADDR_ANY);retval = bind(sockfd, (struct sockaddr *)&serverAddr, sizeof(serverAddr));if (retval < 0) {printf("bind failed, %ld!\r\n", retval);goto do_cleanup;}printf("bind to port %hu success!\r\n", PARAM_SERVER_PORT);retval = recvfrom(sockfd, message, sizeof(message), 0, (struct sockaddr *)&clientAddr, &clientAddrLen);if (retval < 0) {printf("recvfrom failed, %ld!\r\n", retval);goto do_cleanup;}printf("recv message {%s} %ld done!\r\n", message, retval);printf("peer info: ipaddr = %s, port = %hu\r\n", inet_ntoa(clientAddr.sin_addr), ntohs(clientAddr.sin_port));retval = sendto(sockfd, message, strlen(message), 0, (struct sockaddr *)&clientAddr, sizeof(clientAddr));if (retval <= 0) {printf("send failed, %ld!\r\n", retval);goto do_cleanup;}printf("send message {%s} %ld done!\r\n", message, retval);do_cleanup:printf("do_cleanup...\r\n");close(sockfd);DisconnectWithHotspot(netId);
}SYS_RUN(UdpServerTest);

使用build，編譯成功后，使用upload進行燒錄。