客户端-服务器消息传递：测试1

day5/weak_task/da.c

@@ -0,0 +1,57 @@
+// a->客户端
+#include <stdio.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <unistd.h>
+#include <string.h>
+
+int main(int argc, char const *argv[])
+{
+    int sock_fd = socket(AF_INET, SOCK_DGRAM, 0);
+    if (sock_fd < 0)
+    {
+        perror("socket");
+        return -1;
+    }
+
+    struct sockaddr_in addr;
+    bzero(&addr, sizeof(addr));
+    addr.sin_family = AF_INET;
+    addr.sin_port = htons(8000);
+    addr.sin_addr.s_addr = inet_addr("127.0.0.1"); // 指定服务器地址
+
+    while (1)
+    {
+        // 创建发送的数据
+        int n = 5;
+        printf("请输入内容:\n");
+        scanf("%d", &n);
+
+        // 发送 udp 数据
+        ssize_t sendnum = sendto(sock_fd, &n, sizeof(n), 0, (struct sockaddr *)&addr, sizeof(addr)); // 将 buf 数据发送给服务器
+        if (sendnum > 0)
+        {
+            perror("发送成功\n");
+        }
+
+        socklen_t addrlen = sizeof(addr);
+
+        char recvbuf[128] = "";
+
+        ssize_t recvlen = recvfrom(sock_fd, recvbuf, sizeof(recvbuf), 0, (struct sockaddr *)&addr, &addrlen); // 从服务器获取数据到 buf
+        if (recvlen < 0)
+        {
+            perror("recvfrom");
+            return 1;
+        }
+
+        printf("从服务器获取内容为 %s\n", recvbuf);
+        if (strncmp(recvbuf, "bye", 3) == 0)
+            break;
+    }
+
+    close(sock_fd);
+
+    return 0;
+}

day5/weak_task/db.c

@@ -0,0 +1,73 @@
+// b->服务端
+#include <stdio.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/socket.h>
+
+int main(int argc, char const *argv[])
+{
+    int sock_fd = socket(AF_INET, SOCK_DGRAM, 0);
+    if (sock_fd < 0)
+    {
+        perror("socket");
+        return -1;
+    }
+
+    struct sockaddr_in addr;
+    bzero(&addr, sizeof(addr));
+    addr.sin_family = AF_INET;
+    addr.sin_port = htons(8000);
+    addr.sin_addr.s_addr = htonl(INADDR_ANY);
+
+    if (bind(sock_fd, (struct sockaddr *)&addr, sizeof(addr)) != 0)
+    {
+        perror("bind");
+    }
+    else
+    {
+        printf("bind success\n");
+
+        struct sockaddr_in src_addr;
+        int n = 0; // 接收数的空间
+        socklen_t socklen = sizeof(src_addr);
+        while (1)
+        {
+            bzero(&src_addr, sizeof(src_addr));
+
+            // 接收数据，如果数据未到达，则会阻塞，直到数据到达为止
+            ssize_t len = recvfrom(sock_fd, &n, sizeof(n), 0, (struct sockaddr *)&src_addr, &socklen);
+            if (len < 0)
+            {
+                perror("recvfrom");
+                break;
+            }
+
+            char srcIP[INET_ADDRSTRLEN];                                           // 16
+            int port = ntohs(src_addr.sin_port);                                   // 将网络字节序转化为本地字节序
+            inet_ntop(AF_INET, &src_addr.sin_addr.s_addr, srcIP, INET_ADDRSTRLEN); // 将网络数字转换为点分十进制 ip
+
+            printf("从 %s:%d 位置接收到的数字为(%lu Bytes): %d\n", srcIP, port, len, n);
+
+
+            char sendbuf[128] = "";
+
+            if (n == 1)
+                strcpy(sendbuf, "disen666");
+            else if (n == 2)
+                strcpy(sendbuf, "jack good");
+            else if (n == 3)
+                strcpy(sendbuf, "disen888");
+            else if (n == 4)
+                strcpy(sendbuf, "bye");
+
+            sendto(sock_fd, &sendbuf, strlen(sendbuf), 0, (struct sockaddr *)&src_addr, socklen);
+            printf("发送回去内容为 %s\n", sendbuf);
+        }
+    }
+
+    close(sock_fd);
+
+    return 0;
+}