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- #include <stdlib.h>
- #include <stdio.h>
- #include <unistd.h>
- #include <string.h>
- #include <sys/types.h>
- #include <sys/socket.h>
- #include <sys/wait.h>
- #include <arpa/inet.h>
- #include <netinet/in.h>
- #define SRV_IP "127.0.0.1"
- #define PORT 9930
- #define BUFLEN 512
- #define NPACK 10
- enum { SINGLE, PARALLEL } mode = PARALLEL;
- int do_fork = 0;
- int pipefds[2];
- int server(void)
- {
- struct sockaddr_in si_me, si_other;
- int s, i;
- socklen_t slen = sizeof(si_other);
- char buf[BUFLEN];
- if ((s=socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP))==-1) {
- fprintf(stderr, "socket() failed\n");
- exit(1);
- }
- memset((char *) &si_me, 0, sizeof(si_me));
- si_me.sin_family = AF_INET;
- si_me.sin_port = htons(PORT);
- si_me.sin_addr.s_addr = htonl(INADDR_ANY);
- if (bind(s, (struct sockaddr *) &si_me, sizeof(si_me))==-1) {
- fprintf(stderr, "bind() failed\n");
- exit(1);
- }
- if (mode == PARALLEL) {
- close(pipefds[0]);
- char byte = 0;
- write(pipefds[1], &byte, 1);
- }
- if (do_fork) {
- if (fork() > 0) {
- close(s);
- wait(NULL);
- return 0;
- }
- }
- for (i=0; i<NPACK; i++) {
- if (recvfrom(s, buf, BUFLEN, 0, (struct sockaddr *) &si_other,
- &slen)==-1) {
- fprintf(stderr, "recvfrom() failed\n");
- exit(1);
- }
- printf("Received packet from %s:%d\nData: %s\n",
- inet_ntoa(si_other.sin_addr), ntohs(si_other.sin_port), buf);
- }
- close(s);
- if (do_fork)
- exit(0);
- return 0;
- }
- int client(void)
- {
- struct sockaddr_in si_other;
- int s, i;
- socklen_t slen = sizeof(si_other);
- char buf[BUFLEN]= "hi";
- int res;
- if (mode == PARALLEL) {
- close(pipefds[1]);
- char byte = 0;
- read(pipefds[0], &byte, 1);
- }
- if ((s=socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP))==-1) {
- fprintf(stderr, "socket() failed\n");
- exit(1);
- }
- if (do_fork) {
- if (fork() > 0) {
- close(s);
- wait(NULL);
- return 0;
- }
- }
- memset((char *) &si_other, 0, sizeof(si_other));
- si_other.sin_family = AF_INET;
- si_other.sin_port = htons((PORT));
- if (inet_aton(SRV_IP, &si_other.sin_addr)==0) {
- fprintf(stderr, "inet_aton() failed\n");
- exit(1);
- }
- for (i=0; i<10; i++) {
- printf("Sending packet %d\n", i);
- sprintf(buf, "This is packet %d", i);
- if ( (res = sendto(s, buf, BUFLEN, 0, (struct sockaddr *) &si_other,
- slen))== -1) {
- fprintf(stderr, "sendto() failed\n");
- exit(1);
- }
- }
- close(s);
- if (do_fork)
- exit(0);
- return 0;
- }
- int main(int argc, char ** argv)
- {
- if (argc > 1) {
- if (strcmp(argv[1], "client") == 0) {
- mode = SINGLE;
- client();
- return 0;
- }
- if (strcmp(argv[1], "server") == 0) {
- mode = SINGLE;
- server();
- return 0;
- }
- if (strcmp(argv[1], "fork") == 0) {
- do_fork = 1;
- goto old;
- }
- }
- else {
- old:
- pipe(pipefds);
- int pid = fork();
- if (pid == 0)
- client();
- else {
- server();
- waitpid(pid, NULL, -1);
- }
- }
- return 0;
- }
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