91 lines
2.2 KiB
C
91 lines
2.2 KiB
C
#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 <sys/types.h>
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#include <sys/socket.h>
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#include <arpa/inet.h>
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#include <netinet/in.h>
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#include <signal.h>
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#define MAXLINE 1024
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#define SIZE 20
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int sockfd;
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void cleanUp(int signum);
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int main(int argc, char* argv[])
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{
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char ipaddr[SIZE] = "127.0.0.1";
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int port = 9000;
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char buffer[MAXLINE];
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char *confirmation = "Message received";
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struct sockaddr_in servaddr, cliaddr;
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int n;
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socklen_t len;
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/* skapa socket */
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if ( (sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0 )
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{
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perror("socket creation failed");
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return 1;
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}
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/* kontrollera om vi angav en lyssnar-adress */
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if (argc == 2)
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{
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strncpy(ipaddr, argv[1], SIZE-1);
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}
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/* registrera signalhanterarna */
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signal(SIGTERM, cleanUp);
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signal(SIGABRT, cleanUp);
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signal(SIGQUIT, cleanUp);
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signal(SIGINT, cleanUp);
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/* nolla adress-strukturerna innan vi använder dem */
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memset(&servaddr, 0, sizeof(servaddr));
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memset(&cliaddr, 0, sizeof(cliaddr));
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/* information om IP-adress och port */
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servaddr.sin_family = AF_INET; /* IPv4 */
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servaddr.sin_addr.s_addr = inet_addr(ipaddr);
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servaddr.sin_port = htons(port);
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/* knyt ihop vår socket med adressen */
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if ( bind(sockfd, (const struct sockaddr *)&servaddr,
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sizeof(servaddr)) < 0 )
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{
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perror("bind failed");
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return 1;
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}
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len = sizeof(cliaddr); /* storleken på adressen */
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/* ta emot udp-paket och loopa för evigt */
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while(1)
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{
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n = recvfrom(sockfd, (char *)buffer, MAXLINE,
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MSG_WAITALL, ( struct sockaddr *) &cliaddr,
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&len);
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buffer[n] = '\0'; /* avsluta strängen med null */
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/* skriv ut meddelandet vi tog emot från klienten och skicka en
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bekräftelse */
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printf("Client: %s\n", buffer);
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sendto(sockfd, (const char *)confirmation,
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strlen(confirmation), 0,
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(const struct sockaddr *) &cliaddr, len);
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printf("Confirmation message sent to client\n");
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}
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/* vi når aldrig hit - men fall i fall */
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close(sockfd);
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return 0;
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}
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void cleanUp(int signum)
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{
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printf("Quitting gracefully and closing the socket\n");
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close(sockfd);
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exit(0);
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}
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