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/* client.c
* Greatly inspired from examples written by tmouse, July 2005
* http://cboard.cprogramming.com/showthread.php?t=67469
* Modified to run multi-platform by Christian Beier <dontmind@freeshell.org>.
*/
#ifndef __MINGW32__
#include <unistd.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include "msock.h"
#define MULTICAST_RECV_BUF 10240
#define MULTICAST_SO_RCVBUF 425984
#define DEFAULT_MCAST_IP_STR "ff02::114"
#define DEFAULT_PORT_STR "9000"
/* Cmdline Arguments */
char *prog_name = NULL;
char *mcast_ip = NULL;
char *port = NULL;
/* Sockets as global, used everywhere, even in die() */
SOCKET mcast_sock = (SOCKET) -1; /* Multicast socket for receiving data */
SOCKET ucast_sock = (SOCKET) -1; /* Unicast socket for give feedback to server */
/* Buffer used for earch recvfrom() */
char recvbuf[MULTICAST_RECV_BUF];
/* Strings to print out representation of various states of the program */
const char * const state_str[] = {
"exiting",
"wait_hello_and_connect_back",
"wait_start_and_start_job",
"receive_data",
"finalize_job",
"is_there_more_job"
};
/* Some boring funcs you didn't want to read now */
void die(char* msg);
void usage(char *msg);
void arg_parse(int argc, char* argv[]);
/* Parts of the "protocol", definitions are after main() */
int wait_hello_and_connect_back();
int wait_start_and_start_job();
int receive_data();
int finalize_job();
int is_there_more_job();
int main(int argc, char* argv[]) {
int state = 1; /* state of the "protocol" state machine */
int res;
arg_parse(argc, argv);
/* Finite state machine */
while ( state > 0 ) {
fprintf(stderr, "Now in %s state\n", state_str[state]);
switch ( state ) {
case 1: state = (wait_hello_and_connect_back() == 0)?2:1; break;
case 2: state = (wait_start_and_start_job() == 0)?2:3; break;
case 3: res = receive_data();
if (res==0) state = 4;
else if (res==1) state=3;
else state = -1;
break;
case 4: state = (finalize_job() == 0)?5:-2; break;
case 5: state = (is_there_more_job() == 0)?2:0; break;
}
}
if ( mcast_sock > 0 ) {
close(mcast_sock);
}
if ( state < 0 )
return -state;
return EXIT_SUCCESS;
}
int wait_hello_and_connect_back() {
/* Buffers for host and service strings after resolve */
char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];
/* Server address, filled by system after first recvfrom */
struct sockaddr_storage peer_addr;
socklen_t peer_addr_len;
/* Various needed variables */
ssize_t nread;
int res;
/* Setup mcast_sock */
if ( mcast_sock > 0 ) {
close(mcast_sock);
mcast_sock = 0;
}
mcast_sock = mcast_recv_socket(mcast_ip, port, MULTICAST_SO_RCVBUF);
if(mcast_sock < 0)
usage("Could not setup multicast socket. Wrong args given ?");
/* Wait for a single datagram from the server (for sync, no check on contain) */
peer_addr_len = sizeof(struct sockaddr_storage);
nread = recvfrom(mcast_sock, recvbuf, MULTICAST_RECV_BUF, 0, (struct sockaddr *) &peer_addr, &peer_addr_len);
if (nread < 0 ) {
perror("recvfrom() failed");
return -1;
}
/* Get peer informations as strings from peer_addr */
res = getnameinfo((struct sockaddr *) &peer_addr, peer_addr_len,
hbuf, NI_MAXHOST, sbuf, NI_MAXSERV, NI_NUMERICSERV);
if ( res != 0 ) {
fprintf(stderr, "getnameinfo: %s\n", gai_strerror(res));
return -2;
}
/* Connect back to the server, with reliable unicast */
if ( ucast_sock > 0 ) {
close(ucast_sock);
}
ucast_sock = ucast_client_socket(hbuf,port);
if(ucast_sock < 0) {
fprintf(stderr, "Could not setup unicast socket or connect to %s:%s\n", hbuf, port);
return -3;
}
return 0;
}
int wait_start_and_start_job() {
ssize_t nread, nwrite;
/* Wait for a "start" datagram from the server */
nread = recvfrom(mcast_sock, recvbuf, MULTICAST_RECV_BUF, 0, NULL, 0);
if (nread < 0 ) {
perror("recvfrom() failed");
return -1;
}
if ( nread >= 5 && strncmp("start", recvbuf, 5) == 0 ) {
nwrite = write(ucast_sock, "ready", 5);
if ( nwrite < 0 ) {
fprintf(stderr, "write() failed\n");
return -2;
}
if (nwrite != 5) {
fprintf(stderr, "write() short\n");
return -3;
}
return 1;
}
return 0;
}
int receive_data() {
ssize_t nread;
uint32_t seq;
uint16_t datalen;
/* Wait for a "dataN" datagram from the server */
nread = recvfrom(mcast_sock, recvbuf, MULTICAST_RECV_BUF, 0, NULL, 0);
if (nread < 0 ) {
perror("recvfrom() failed");
return -1;
}
if ( nread >= 10 && strncmp("data", recvbuf, 4) == 0 ) {
seq = ntohl( *( (uint32_t *) recvbuf+1 ) );
datalen = ntohs( *( (uint16_t *) recvbuf+4 ) );
//fprintf(stderr, "debug seq==%i, datalen==%hi\n", seq, datalen);
if ( nread != (10 + datalen) ) {
fprintf(stderr, "debug nread==%zi, (10 + datalen)==%i\n", nread, (10 + datalen));
//TODO nack ?
return -2;
}
fprintf(stdout, "data #%i, ", seq);
fwrite(recvbuf+10, datalen, 1, stdout);
fflush(stdout);
//TODO buffer zero copy, ack
return 1;
}
return 0;
}
int finalize_job() {
return 0;
}
int is_there_more_job() {
return 1;
}
void die(char* msg) {
fprintf(stderr, "%s\n", msg);
if (mcast_sock > 0)
close(mcast_sock);
if (ucast_sock > 0)
close(ucast_sock);
exit(EXIT_FAILURE);
}
void usage(char *msg) {
char ubuf[256];
if ( msg != NULL )
fprintf(stderr, "%s\n", msg);
ubuf[0] = '\0';
snprintf(ubuf, 255, "Usage: %s [port] [mcast_ip]\n", prog_name);
die(ubuf);
}
void arg_parse(int argc, char* argv[]) {
prog_name = argv[0];
if ( argc > 3 )
usage("Too many arguments");
port = (argc >= 2)?argv[1]:DEFAULT_PORT_STR;
mcast_ip = (argc >= 3)?argv[2]:DEFAULT_MCAST_IP_STR;
}
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