客户端
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <netinet/in.h> #include <sys/socket.h> #include <arpa/inet.h> #include <unistd.h> // UDP 通讯程序代码-Client int main(int argc, char* argv[]) { if (argc < 2) { printf("Please input something!\r\n"); exit(1); } // 因为是UDP套接字,使用SOCK_DGRAM,而不是SOCK_STREAM int sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP/*TCP使用0*/); if (sock < 0) { printf("创建套接字失败!\r\n"); exit(1); } // Send to struct sockaddr_in toAddr; memset(&toAddr, 0, sizeof(toAddr)); toAddr.sin_family = AF_INET; toAddr.sin_addr.s_addr = inet_addr("127.0.0.1"); toAddr.sin_port = htons(4000); // Start to send to if (sendto(sock, argv[1], strlen(argv[1]), 0, (struct sockaddr*)&toAddr, sizeof(toAddr)) != strlen(argv[1])) { printf("sendto()函数使用失败!,\r\n"); close(sock); exit(1); } // Receive form struct sockaddr_in fromAddr; char recvBuffer[128] = {0}; unsigned int fromLen = sizeof(fromAddr); if( recvfrom(sock, recvBuffer, 128, 0, (struct sockaddr*)&fromAddr, &fromLen) < 0) { printf("recvfrom()函数使用失败!,\r\n"); close(sock); exit(1); } // 把接收的数据输出到屏幕上 printf("recvfrom()result: %s\r\n", recvBuffer); close(sock); return 0; }
服务端
// UDP Server #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <netinet/in.h> #include <sys/socket.h> #include <arpa/inet.h> #include <unistd.h> int main() { // Create UDP socket int sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); if (sock < 0) { printf("Create socket faild\r\n"); exit(1); } // Bind socket and the client of send link request struct sockaddr_in fromAddr; memset(&fromAddr, 0, sizeof(fromAddr)); fromAddr.sin_family = AF_INET; fromAddr.sin_addr.s_addr = htonl(INADDR_ANY); fromAddr.sin_port = htons(4000); if (bind(sock, (struct sockaddr*)&fromAddr, sizeof(fromAddr)) < 0) { printf("Bind socket faild!\r\n"); close(sock); exit(1); } struct sockaddr_in toAddr; char recvBuffer[128] = {0}; int recvLen = -1; unsigned int addrLen = sizeof(toAddr); while(1) { if ((recvLen = recvfrom(sock, recvBuffer, 128, 0, (struct sockaddr*)&toAddr, &addrLen)) < 0) { printf("Receive message faild!\r\n"); close(sock); exit(1); } if (recvLen > 0) { printf("Recive message:%s\r\n", recvBuffer); } if (sendto(sock, recvBuffer, recvLen, 0, (struct sockaddr*)&toAddr, sizeof(toAddr)) != recvLen) { printf("sendto faild\r\n"); close(sock); exit(1); } } close(sock); return 0; }