1 files changed, 184 insertions, 0 deletions

diff --git a/udp2lcm.c b/udp2lcm.c
new file mode 100644
index 0000000..ec8aee8
--- /dev/null
+++ b/udp2lcm.c
@@ -0,0 +1,184 @@
+// Encoded in UTF-8
+
+/*
+ * struct path_ctrl_t
+ * {
+ *     int8_t cmd;
+ *     int8_t speed;
+ * }
+ * 这是与轮控模块通信的数据结构，speed为0-100表示速度
+ * cmd为0停，1前，2左，3右
+ */
+#include "path/path_ctrl_t.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define MAX_BUFFER_SIZE 1024
+#define PORT 5001
+
+pthread_t udpRecv, udpSend;
+int8_t heartBeat[9] = {0}; // 用于存储需要发送的心跳信息
+// clientIP用于存储手机端IP地址，仅在第一次接收消息后修改
+// 本身就是inet_ntoa(clientAddr.sin_addr)，二者内容完全一致
+struct sockaddr_in clientAddr;
+char clientIP[20] = "";
+lcm_t *path_ctrl_lcm;
+
+bool LCMInit();
+void udpSendHandler();
+void udpRecvHandler();
+void parseCmd(const char *buffer, int bytesReceived);
+
+int main() {
+    if (!LCMInit()) {
+        fprintf(stderr, "Error: Failed to initialize LCM\n");
+        return -1;
+    }
+    // 开启udp接收线程
+    pthread_create(&udpRecv, NULL, udpRecvHandler, NULL);
+    return 0;
+}
+
+bool LCMInit() {
+    // TODO: 在这里同意初始化各个LCM变量
+    // ATTENTION:
+    // 是否在这里订阅各个通道、各个通道需要在什么地方订阅，需要慎重考虑
+    if ((path_ctrl_lcm = lcm_create(NULL)) == NULL) {
+        fprintf(stderr, "Error: Failed to create Path Ctrl LCM\n");
+        return false;
+    }
+
+    return true;
+}
+
+void udpRecvHandler() {
+    int socketfd = -1;
+    char buffer[MAX_BUFFER_SIZE];
+    struct sockaddr_in serverAddr;
+    socklen_t addrLen = sizeof(serverAddr);
+    int bytesReceived;
+
+    int retval;
+    struct pollfd fds;
+
+    if ((socketfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1) {
+        fprintf(stderr, "Error: Failed to create socket\n");
+        return;
+    }
+    memset((char *)&serverAddr, 0, sizeof(serverAddr));
+    memset(buffer, 0, sizeof(buffer));
+    serverAddr.sin_family = AF_INET;
+    serverAddr.sin_port = htons(port);
+    serverAddr.sin_addr.s_addr = htonl(INADDR_ANY);
+
+    if (bind(socketfd, (struct sockaddr *)&serverAddr, sizeof(serverAddr)) ==
+        -1) {
+        fprintf(stderr, "Error: Bind failed\n");
+        close(socketfd);
+        return;
+    }
+
+    bytesReceived = recvfrom(socketfd, buffer, MAX_BUFFER_SIZE, 0,
+                             (struct sockaddr *)&clientAddr, &addrLen);
+    if (bytesReceived == -1) {
+        fprintf(stderr, "Error: Failed to receive data\n");
+        close(socketfd);
+        return;
+    }
+    printf("Start message from %s: %s\n", inet_ntoa(clientAddr.sin_addr),
+           buffer);
+    strcpy(clientIP, inet_ntoa(clientAddr.sin_addr));
+
+    // 在接收到第一条消息之后，开启udp发送线程，用于发送心跳信息
+    if (pthread_create(&udpSend, NULL, udpSendHandler, NULL) != 0) {
+        fprintf(stderr, "Error creating udpSend thread\n");
+        close(socketfd);
+        exit(-1);
+    }
+
+    fds.fd = socketfd;
+    fds.events = POLLIN;
+
+    while (true) {
+        retval = poll(&fds, 1, 3000);
+        if (retval == -1) {
+            fprintf(stderr, "Error: select failed\n");
+            break;
+        } else if (retval == 0) {
+            printf("No data within three seconds.\n");
+            speedControl(0, 0);
+        } else {
+            bytesReceived = recvfrom(socketfd, buffer, MAX_BUFFER_SIZE, 0,
+                                     (struct sockaddr *)&clientAddr, &addrLen);
+            if (bytesReceived == -1) {
+                fprintf(stderr, "Error: Failed to receive data\n");
+                continue;
+            }
+            printf("Massage from client %s: ", clientIP);
+            for (int i = 0; i < bytesReceived; i++) {
+                printf("%02x ", buffer[i]);
+            }
+            printf("\n");
+            parseCmd(buffer, bytesReceived);
+        }
+    }
+}
+
+void udpSendHandler() {
+    // 创建UDP套接字
+    int sockfd = -1;
+    struct sockaddr_in serverAddr;
+    if ((sockfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1) {
+        fprintf(stderr, "Error: Failed to create socket\n");
+        return;
+    }
+
+    memset((char *)&serverAddr, 0, sizeof(serverAddr));
+    serverAddr.sin_family = AF_INET;   // 设置地址族为IPv4
+    serverAddr.sin_port = htons(port); // 设置端口号
+    if (inet_aton(clientIP, &serverAddr.sin_addr) == 0) {
+        fprintf(stderr, "Error: Failed to convert IP address\n");
+        close(sockfd);
+        return;
+    }
+
+    while (true) {
+        sendto(sockfd, (const char *)heartBeat, 9, 0,
+               (struct sockaddr *)&serverAddr, sizeof(serverAddr));
+        printf("Send: Data %02x udpSend successfully!\n", a);
+        sleep(1);
+    }
+}
+
+void parseCmd(const char *buffer, int bytesReceived) {
+    // TODO: 完成本函数的内容
+    if (buffer == NULL || strlen(buffer) != 9) {
+        fprintf(stderr, "Error: Invalid message\n");
+        return;
+    }
+
+    if (buffer[0] == 0) {
+        // 手机端用来与udp2lcm服务器建立连接的初始化消息
+        fprintf(stderr, "Why Init cmd here?\n");
+    } else if (buffer[0] == 1) {
+        // 建图过程中，手机端遥控小车进行移动，命令下发至轮控模块
+        path_ctrl_t path;
+        path.cmd = buffer[1];
+        path.speed = buffer[2];
+        path_ctrl_t_publish(path_ctrl_lcm, "wheel_ctrl", &path);
+    } else if (buffer[0] == 2) {
+        /*
+         * 结束建图，主要有以下几个任务：
+         * - 向轮控模块发送停止命令
+         * - 通知算法模块结束建图（FIXME: 是否接受算法模块的回应？）
+         * - 拉起http服务器进程
+         * - 向手机端通知建图完成
+         * -
+         * 开始通过lcm接受算法给出的实时坐标，存储至heartBeat数组中（对应格式）
+         */
+    } else if (buffer[0] == 3) {
+        // 手机发来的终点坐标，转发给算法模块
+        ;
+    }
+}
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