archie/prospero/lib/ardp/ardp_xmit.c

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2024-05-27 16:13:40 +02:00
/*
* Copyright (c) 1993 by the University of Southern California
*
* For copying and distribution information, please see the file
* <usc-license.h>.
*
* Written by bcn 1/93 to send a list of packets to a destination
*/
#include <usc-license.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <ardp.h>
#include <pmachine.h> /* for bcopy() and select() */
extern int pfs_debug; /* Debug level */
extern int ardp_port; /* Opened UDP port */
/*
* ardp_xmit - transmits packets in req->trns
*
* ardp_xmit takes a pointer to a request structure of type RREQ and a
* window size. It then sends the packet on the request structure
* transmit queue to the peer address in the request structure starting after
* the indicated peer rcvd_thru value, and up to the number of packets
* specified by the window size. It returns ARDP_SUCCESS on success and
* returns an error code on failure.
*
* This is called on both the client and server side, called respectively by
* ardp_send() and ardp_pr_actv().
*/
int
ardp_xmit(RREQ req, /* Request structure with packets to send */
int window) /* Max packets to send at once. Note that
right now this is always identical to
req->pwindow_sz.
0 means infinite window size
-1 means just send an ACK; don't send any
data packets. */
{
PTEXT ptmp; /* Packet pointer for stepping through trns */
unsigned short stmp; /* Temp short for conversions */
int ns; /* Number of bytes actually sent */
static PTEXT ack = NOPKT; /* Only an ack to be sent */
if(window < 0 || req->prcvd_thru >= req->trns_tot) {
/* All our packets got through, send acks only */
if(ack == NOPKT) {
ack = ardp_ptalloc();
/* Add header */
ack->start -= 9;
ack->length += 9;
*(ack->start) = (char) 9;
/* An unsequenced control packet */
bzero4(ack->start+3);
}
/* Received Through */
stmp = htons(req->rcvd_thru);
bcopy2(&stmp,ack->start+7);
/* Connection ID */
bcopy2(&(req->cid),ack->start+1);
ptmp = ack;
}
else ptmp = req->trns;
/* Note that we don't want to get rid of packts before the */
/* peer received through since the peer might later tell */
/* us it forgot them and ask us to send them again */
/* XXX whether this is allowable should be an application */
/* specific configration option. */
while(ptmp) {
if((window > 0) && (ptmp->seq > req->prcvd_thru + window)) break;
if((ptmp->seq == 0) || (ptmp->seq > req->prcvd_thru)) {
if (pfs_debug >= 6) {
if (req->peer.sin_family == AF_INET)
fprintf(stderr,
"Sending message%s (cid=%d) (seq=%d) to %s(%d)...",
(ptmp == ack) ? " (ACK only)" : "",
ntohs(req->cid), ntohs(ptmp->seq),
inet_ntoa(req->peer_addr), PEER_PORT(req));
else fprintf(stderr,"Sending message...");
(void) fflush(stderr);
}
ns = sendto(ardp_port,(char *)(ptmp->start), ptmp->length, 0,
&(req->peer), S_AD_SZ);
if(ns != ptmp->length) {
if (pfs_debug >= 1) {
fprintf(stderr,"\nsent only %d/%d: ",ns, ptmp->length);
perror("");
}
return(ARDP_NOT_SENT);
}
if (pfs_debug >= 6) fprintf(stderr,"Sent.\n");
}
ptmp = ptmp->next;
}
return(ARDP_SUCCESS);
}