Witam. Muszę przerobić ten kod tak, żeby mozna było pisać z jednego portu (chat UDP)
Otwierając dwa terminale (loguje sie na 2 roznych maszynach)
Na 1 terminalu: ./chat 5555 (IP drugiej maszyny do ktorej bede wysylac odpowiedzi) 5556
Na 2 terminalu: ./chat 5556 (IP pierwszej maszyny do ktorej bede wysylac odpowiedzi) 5555
// gdzie 5555 i 5556 to porty
a o to kod:
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <errno.h>
#include <fcntl.h>
#include <netinet/in.h>
#include <poll.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
void start_chat(int sock_fd, struct sockaddr_in *peer)
{
int ret;
ssize_t bytes;
char input_buffer[1024];
char output_buffer[1024];
struct pollfd fds[2];
fds[0].fd = 0;
fds[1].fd = sock_fd;
fds[0].events = POLLIN | POLLPRI;
fds[1].events = POLLIN | POLLPRI;
while (1)
{
ret = poll(fds, 2, -1);
if (ret < 0)
{
printf("Error - poll zwrocil error: %s\n", strerror(errno));
break;
}
if (ret > 0)
{
/* Regardless of requested events, poll() can always return these */
if (fds[0].revents & (POLLERR | POLLHUP | POLLNVAL))
{
printf("Error - stdin error\n");
break;
}
if (fds[1].revents & (POLLERR | POLLHUP | POLLNVAL))
{
printf("Error - socket error\n");
break;
}
if (fds[0].revents & (POLLIN | POLLPRI))
{
bytes = read(0, output_buffer, sizeof(output_buffer));
if (bytes < 0)
{
printf("Error - stdin error: %s\n", strerror(errno));
break;
}
printf("Sending: %.*s\n", (int)bytes, output_buffer);
bytes = sendto(sock_fd, output_buffer, bytes, 0,
(struct sockaddr *)peer, sizeof(struct sockaddr_in));
if (bytes < 0)
{
printf("Error - sendto error: %s\n", strerror(errno));
break;
}
}
if (fds[1].revents & (POLLIN | POLLPRI))
{
bytes = recvfrom(sock_fd, input_buffer, sizeof(input_buffer),
0, NULL, NULL);
if (bytes < 0)
{
printf("Error - recvfrom error: %s\n", strerror(errno));
break;
}
if (bytes > 0)
{
printf("Received: %.*s\n", (int)bytes, input_buffer);
}
}
}
}
}
int main(int argc, char *argv[])
{
unsigned long local_port;
unsigned long remote_port;
int sock_fd;
struct sockaddr_in server_addr;
struct sockaddr_in peer_addr;
if (argc < 4)
{
printf("Usage: %s <local port> <remote host> <remote port>\n", argv[0]);
return 1;
}
local_port = strtoul(argv[1], NULL, 0);
if (local_port < 1 || local_port > 65535)
{
printf("Error - invalid local port '%s'\n", argv[1]);
return 1;
}
remote_port = strtoul(argv[3], NULL, 0);
if (remote_port < 1 || remote_port > 65535)
{
printf("Error - invalid remote port '%s'\n", argv[3]);
return 1;
}
peer_addr.sin_family = AF_INET;
peer_addr.sin_port = htons(remote_port);
if (inet_aton(argv[2], &peer_addr.sin_addr) == 0)
{
printf("Error - invalid remote address '%s'\n", argv[2]);
return 1;
}
/* Create UDP socket */
sock_fd = socket(AF_INET, SOCK_DGRAM, 0);
if (sock_fd < 0)
{
printf("Error - failed to open socket: %s\n", strerror(errno));
return 1;
}
server_addr.sin_family = AF_INET;
server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
server_addr.sin_port = htons(local_port);
if (bind(sock_fd, (struct sockaddr *)(&server_addr),
sizeof(server_addr)) < 0)
{
printf("Error - failed to bind socket: %s\n", strerror(errno));
return 1;
}
start_chat(sock_fd, &peer_addr);
close(sock_fd);
return 0;
}