|
|
/* is_seqnum_cl.c
|
|
A simple Internet stream socket client. This client requests a sequence
|
number from the server.
|
|
See also is_seqnum_sv.c.
|
*/
|
#include <netdb.h>
|
#include "is_seqnum.h"
|
|
int
|
main(int argc, char *argv[])
|
{
|
char request[1024]; /* Requested length of sequence */
|
char response[1024];
|
int cfd;
|
ssize_t numRead;
|
struct addrinfo hints;
|
struct addrinfo *result, *rp;
|
|
if (argc < 2 || strcmp(argv[1], "--help") == 0)
|
printf("%s server-host\n", argv[0]);
|
|
/* Call getaddrinfo() to obtain a list of addresses that
|
we can try connecting to */
|
|
memset(&hints, 0, sizeof(struct addrinfo));
|
hints.ai_canonname = NULL;
|
hints.ai_addr = NULL;
|
hints.ai_next = NULL;
|
hints.ai_family = AF_UNSPEC; /* Allows IPv4 or IPv6 */
|
hints.ai_socktype = SOCK_STREAM;
|
hints.ai_flags = AI_NUMERICSERV;
|
|
if (getaddrinfo(argv[1], PORT_NUM, &hints, &result) != 0)
|
err_exit(errno, "getaddrinfo");
|
|
/* Walk through returned list until we find an address structure
|
that can be used to successfully connect a socket */
|
|
for (rp = result; rp != NULL; rp = rp->ai_next) {
|
cfd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
|
if (cfd == -1)
|
continue; /* On error, try next address */
|
|
if (connect(cfd, rp->ai_addr, rp->ai_addrlen) != -1)
|
break; /* Success */
|
|
/* Connect failed: close this socket and try next address */
|
|
close(cfd);
|
}
|
|
if (rp == NULL)
|
err_exit(errno, "Could not connect socket to any address");
|
|
freeaddrinfo(result);
|
|
/* Send requested sequence length, with terminating newline */
|
|
fputs("request:", stdout);
|
if(fgets(request, 1024, stdin) != NULL) {
|
if (write(cfd, request, strlen(request)) != strlen(request))
|
err_exit(errno, "Partial/failed write (reqLenStr)");
|
|
numRead = readLine(cfd, response, 1024);
|
if (numRead == -1)
|
err_exit(errno, "readLine");
|
if (numRead == 0)
|
err_exit(errno, "Unexpected EOF from server");
|
|
printf("response: %s", response); /* Includes '\n' */
|
puts("request:");
|
}
|
exit(EXIT_SUCCESS);
|
}
|
