Chronological Thread 

< Chronological >      < Thread >

---

Hi,

I'm trying to write an echo program using TCP-style sockets in C and getting the program to use multi-stream instead of the default single stream. Problem is, I've read <draft-ietf-tsvwg-sctpsocket-04.txt> about 5 times over, gone through sctpterminal.cc and sctpmultiserver.cc examples, and I still don't understand how to initiate a multi-stream socket.

I've been trying at it for the past week but with no results, which is why I'm attaching my codes below, hoping that someone can point out what's wrong. My problem primary lies at the spot marked by "%%%". I don't know how to use sendmsg() because of all the struct msghdr and cmsghdr stated in the draft and initiating it.

Perhaps someone can also point out some of the important points that I should note when coding the echo server program.

***********************************************************
#include <stdio.h> /* for printf() and fprintf() */
#include <sys/socket.h> /* for socket(), connect(), send(), and recv() */
#include <arpa/inet.h> /* for sockaddr_in and inet_addr() */
#include <stdlib.h> /* for atoi() */
#include <string.h> /* for memset() */
#include <unistd.h> /* for close() */
#include <sys/types.h>
#include <sys/time.h>
#include <ext_socket.h>
#include <net/route.h>
#include <net/if.h>
#include <netinet/in.h>
#include <sctp.h>

#define RCVBUFSIZE 16 /* Size of receive buffer */
#define OUTSTREAM 3 /* Number of out-bound streams */
#define INSTREAM 2 /* Number of in-bound streams */


void DieWithError(char *errorMessage)
{
perror(errorMessage);
exit(1);
}


int main(int argc, char *argv[])
{
int sock; /* Socket descriptor */
struct sockaddr_in echoServAddr;/* Echo server address */
unsigned short echoServPort; /* Echo server port */
char *servIP; /* Server IP address (dotted quad) */
char *echoString; /* String to send to echo server */
char echoBuffer[RCVBUFSIZE]; /* Buffer for echo string */
unsigned int echoStringLen; /* Length of string to echo */
int bytesRcvd, totalBytesRcvd; /* Bytes read in single recv() and total bytes read */
struct sctp_initmsg *sim;

sim->sinit_num_ostreams = OUTSTREAM;
sim->sinit_max_instreams = INSTREAM;
sim->sinit_max_attempts = 3;
sim->sinit_max_init_timeo = 30;

/* Test for correct number of arguments */
if ((argc < 3) || (argc > 4))
{
fprintf(stderr, "Usage: %s <Server IP> <Echo Word> [<Echo Port>]\n", argv[0]);
exit(1);
}

servIP = argv[1]; /* First arg: server IP address (dotted quad) */

echoString = argv[2]; /* Second arg: string to echo */

if (argc == 4)
echoServPort = atoi(argv[3]); /* Use given port, if any */
else
/* 7 is the well-known port for the echo service */
echoServPort = 7;

printf("\nCreating socket... ");
/* Create a reliable, stream socket using TCP-style */
if ((sock = ext_socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP)) < 0)
{
DieWithError("socket() failed");
exit(1);
}
printf("Socket created.\n\n");

/* Setting socket options */
if (ext_setsockopt(IPPROTO_SCTP, SCTP_INITMSG, sim, sizeof(*sim)) < 0)
{
DieWithError("setsockopt() failed");
exit(1);
}

/* Construct the server address structure */
/* Zero out structure */
memset(&echoServAddr, 0, sizeof(echoServAddr));

echoServAddr.sin_family = AF_INET; /* Internet address family */

/* Server IP address */
echoServAddr.sin_addr.s_addr = inet_addr(servIP);

echoServAddr.sin_port = htons(echoServPort); /* Server port */

printf("Connecting to server at %s:%u ... ", servIP, echoServPort);
/* Establish the connection to the echo server */
if (ext_connect(sock, (struct sockaddr *) &echoServAddr, sizeof(echoServAddr)) < 0)
DieWithError("connect() failed");
printf("Connected.\n\n");

echoStringLen = strlen(echoString); /* Determine input length */

printf("Sending message \"%s\" to server... ", echoString);
/* Send the string to the server */
%%% if (ext_sendmsg(sock, ))
DieWithError("send() sent a diff. num. of bytes than expected");
printf("Message sent.\n\n");

/* Receive the same string back from the server */
totalBytesRcvd = 0;

printf("Receiving echo from server... ");
printf("Received: "); /* Setup to print the echoed string */

while (totalBytesRcvd < echoStringLen)
{
/* Receive up to the buffer size (minus 1 to leave space for a null terminator) bytes from the sender */
if ((bytesRcvd = ext_recv(sock, echoBuffer, RCVBUFSIZE - 1, 0)) <= 0)
DieWithError("recv() failed or conn. closed prematurely");

totalBytesRcvd += bytesRcvd; /* Keep tally of total bytes */

echoBuffer[bytesRcvd] = '\0'; /* Terminate the string! */

printf(echoBuffer); /* Print the echo buffer */
}

printf("\n\n"); /* Print a final linefeed */

ext_close(sock);

exit(0);
}
**********************************************************

Desperately need some help here... Thanks a million!!! :)



Oon, Heok Kee
National University of Singapore

_________________________________________________________________
Chat with friends online, try MSN Messenger: http://messenger.msn.com

---

• [SCTP-Discussion] Problem trying to use multi-stream, Oon Heok Kee, 08/29/2002
  • Re: [SCTP-Discussion] Problem trying to use multi-stream, Thomas Dreibholz, 08/29/2002
  • <Possible follow-up(s)>
  • Re: [SCTP-Discussion] Problem trying to use multi-stream, Oon Heok Kee, 08/30/2002
    • Re: [SCTP-Discussion] Problem trying to use multi-stream, Torbjorn Andersson, 08/30/2002
    • Re: [SCTP-Discussion] Problem trying to use multi-stream, Thomas Dreibholz, 08/30/2002

---

Archive powered by MHonArc 2.6.19+.