From 761175ea525dc5204f02411518a594213f48392b Mon Sep 17 00:00:00 2001
From: Greg Hudson <ghudson@mit.edu>
Date: Fri, 21 Aug 1998 02:25:30 +0000
Subject: Don't penalize clients when we get an EAGAIN or ENOBUFS from
 sendto().

---
 server/dispatch.c | 61 +++++++++++++++++++++++++++++++------------------------
 1 file changed, 35 insertions(+), 26 deletions(-)

(limited to 'server/dispatch.c')

diff --git a/server/dispatch.c b/server/dispatch.c
index 50769a7..db66bbe 100644
--- a/server/dispatch.c
+++ b/server/dispatch.c
@@ -499,9 +499,7 @@ nack_release(client)
     for (i = 0; i < NACKTAB_HASHSIZE; i++) {
 	for (nacked = nacktab[i]; nacked; nacked = next) {
 	    next = nacked->next;
-	    if (nacked->dest.addr.sin_addr.s_addr ==
-		client->addr.sin_addr.s_addr &&
-		nacked->dest.addr.sin_port == client->addr.sin_port) {
+	    if (nacked->client == client) {
 		timer_reset(nacked->timer);
 		LIST_DELETE(nacked);
 		free(nacked->packet);
@@ -529,12 +527,14 @@ xmit_frag(notice, buf, len, waitforack)
     char *savebuf;
     Unacked *nacked;
     Code_t retval;
-    int hashval;
+    int hashval, sendfail = 0;
 
     retval = ZSendPacket(buf, len, 0);
     if (retval != ZERR_NONE) {
 	syslog(LOG_WARNING, "xmit_frag send: %s", error_message(retval));
-	return retval;
+	if (retval != EAGAIN)
+	    return retval;
+	sendfail = 1;
     }
 
     /* now we've sent it, mark it as not ack'ed */
@@ -556,7 +556,8 @@ xmit_frag(notice, buf, len, waitforack)
     memcpy(savebuf, buf, len);
 
     sin = ZGetDestAddr();
-    nacked->rexmits = 0;
+    nacked->client = NULL;
+    nacked->rexmits = (sendfail) ? -1 : 0;
     nacked->packet = savebuf;
     nacked->dest.addr = sin;
     nacked->packsz = len;
@@ -580,7 +581,7 @@ xmit(notice, dest, auth, client)
 {
     char *noticepack;
     Unacked *nacked;
-    int packlen;
+    int packlen, sendfail = 0;
     Code_t retval;
 
 #if 0
@@ -641,8 +642,11 @@ xmit(notice, dest, auth, client)
     if (retval != ZERR_NONE) {
 	syslog(LOG_WARNING, "xmit xmit: (%s/%d) %s", inet_ntoa(dest->sin_addr),
 	       ntohs(dest->sin_port), error_message(retval));
-	free(noticepack);
-	return;
+	if (retval != EAGAIN) {
+	    free(noticepack);
+	    return;
+	}
+	sendfail = 1;
     }
 
     /* now we've sent it, mark it as not ack'ed */
@@ -655,7 +659,8 @@ xmit(notice, dest, auth, client)
 	return;
     }
 
-    nacked->rexmits = 0;
+    nacked->client = client;
+    nacked->rexmits = (sendfail) ? -1 : 0;
     nacked->packet = noticepack;
     nacked->dest.addr = *dest;
     nacked->packsz = packlen;
@@ -676,7 +681,6 @@ rexmit(arg)
 {
     Unacked *nacked = (Unacked *) arg;
     int retval;
-    Client *client;
 
 #if 1
     syslog(LOG_DEBUG, "rexmit %s/%d #%d time %d",
@@ -686,22 +690,23 @@ rexmit(arg)
 
     nacked->rexmits++;
     if (rexmit_times[nacked->rexmits] == -1) {
-	/* Unresponsive client, find it in our database. */
-	client = client_find(&nacked->dest.addr.sin_addr,
-			     nacked->dest.addr.sin_port);
-
-	/* unlink & free nacked */
-	LIST_DELETE(nacked);
-	free(nacked->packet);
-	free(nacked);
-
-	/* Kill the client. */
-	if (client) {
-	    server_kill_clt(client);
-	    client_deregister(client, 1);
+	if (!nacked->client
+	    || NOW - nacked->client->last_ack >= CLIENT_GIVEUP_MIN) {
+	    /* The client (if there was one) has been unresponsive.  Give up
+	     * sending this packet, and kill the client if there was one. */
+	    LIST_DELETE(nacked);
+	    free(nacked->packet);
+	    free(nacked);
+	    if (nacked->client) {
+		server_kill_clt(nacked->client);
+		client_deregister(nacked->client, 1);
+	    }
+	    return;
+	} else {
+	    /* The client has sent us an ack recently.  Retry with the maximum
+	     * retransmit time. */
+	    nacked->rexmits--;
 	}
-
-	return;
     }
 
     /* retransmit the packet */
@@ -716,6 +721,8 @@ rexmit(arg)
 	retval = ZSendPacket(nacked->packet, nacked->packsz, 0);
 	if (retval != ZERR_NONE)
 	    syslog(LOG_WARNING, "rexmit xmit: %s", error_message(retval));
+	if (retval == EAGAIN)
+	    nacked->rexmits--;
     }
 
     /* reset the timer */
@@ -834,6 +841,8 @@ nack_cancel(notice, who)
 	if (nacked->dest.addr.sin_addr.s_addr == who->sin_addr.s_addr
 	    && nacked->dest.addr.sin_port == who->sin_port
 	    && ZCompareUID(&nacked->uid, &notice->z_uid)) {
+	    if (nacked->client)
+		nacked->client->last_ack = NOW;
 	    timer_reset(nacked->timer);
 	    free(nacked->packet);
 	    LIST_DELETE(nacked);
-- 
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