/*********************************************************************************
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* Copyright: (C) 2018 LingYun IoT Studio
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* All rights reserved.
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*
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* Filename: udp_server.c
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* Description: This file is UDP socket server sample source code, it will
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* echo back the receive data from client.
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*
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* Version: 1.0.0(10/23/2018)
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* Author: Guo Wenxue <guowenxue@gmail.com>
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* ChangeLog: 1, Release initial version on "2017-10-23 01:41:05 PM"
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*
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********************************************************************************/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <ctype.h>
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#include <errno.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#define DEF_SERV_PORT 8059
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void dump_buf(char *buf, int size)
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{
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int i;
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for(i=0; i<size; i++)
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{
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printf("0x%02x ", buf[i]);
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}
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printf("\n");
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}
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int main(int argc, char **argv)
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{
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struct sockaddr_in servaddr, cliaddr;
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socklen_t cliaddr_len;
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int sockfd;
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char buf[1024];
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char ip[INET_ADDRSTRLEN];
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int i, len;
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int port = DEF_SERV_PORT;
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printf("You can use '%s [port]' to change default port[%d].\n", argv[0], DEF_SERV_PORT);
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if( argc == 2 )
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{
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port = atoi(argv[1]);
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}
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sockfd = socket(AF_INET, SOCK_DGRAM, 0);
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bzero(&servaddr, sizeof(servaddr));
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servaddr.sin_family = AF_INET;
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servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
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servaddr.sin_port = htons(port);
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printf("Start listen on port[%d]\n", port);
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bind(sockfd, (struct sockaddr*)&servaddr, sizeof(servaddr));
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printf("Start Accepting connections ...\n");
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while(1)
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{
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cliaddr_len = sizeof(cliaddr);
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memset(buf, 0, sizeof(buf));
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len = recvfrom(sockfd, buf, sizeof(buf), 0, (struct sockaddr*)&cliaddr, &cliaddr_len);
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if(len == -1)
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{
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printf("recvfrom error: %s\n", strerror(errno));
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}
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printf("Received %d bytes datas from %s at PORT %d\n", len, inet_ntop(AF_INET, &cliaddr.sin_addr, ip, sizeof(ip)),
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ntohs(cliaddr.sin_port));
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printf("%s\n", buf);
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dump_buf(buf, len);
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#if 0
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for(i = 0; i < len; i++)
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{
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buf[i] = toupper(buf[i]);
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}
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dump_buf(buf, len);
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#endif
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len = sendto(sockfd, buf, len, 0, (struct sockaddr*)&cliaddr, sizeof(cliaddr));
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if(len == -1)
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{
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printf("sendto error: %s\n", strerror(errno));
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}
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}
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close(sockfd);
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return 0;
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}
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