From 6c5439b80934cd6e3f0539a07874c3bda18d676d Mon Sep 17 00:00:00 2001
From: Jeffrey Hutzelman <jhutz@cmu.edu>
Date: Wed, 31 Jul 2002 23:35:09 +0000
Subject: [PATCH] deal-with-linux-EAGAIN-returns-when-receiving-20020731

sometimes you get EAGAIN from recvfrom, apparently if a packet comes in with a
bad checksum for instance. we should deal better.
---
 src/kauth/krb_udp.c | 14 ++++++++++++++
 src/rx/rx_lwp.c     |  4 +++-
 src/rx/rx_pthread.c |  3 ++-
 3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/src/kauth/krb_udp.c b/src/kauth/krb_udp.c
index 4f5d9ca268..4154fe1fcb 100644
--- a/src/kauth/krb_udp.c
+++ b/src/kauth/krb_udp.c
@@ -778,6 +778,8 @@ static SocketListener ()
 	    code = recvfrom(sock_kerb, packet.data, sizeof(packet.data), 0,
 			    (struct sockaddr *) &packet.from, &fromLen);
 	    if (code < 0) {
+		if (errno == EAGAIN || errno == ECONNREFUSED) 
+		    goto try_kerb5;
 		perror ("calling recvfrom");
 		break;
 	    }
@@ -792,10 +794,13 @@ static SocketListener ()
 	    packet.time = 0;
 	    process_udp_request (sock_kerb, &packet);
 	} 
+try_kerb5:
 	if ((sock_kerb5 >= 0) && FD_ISSET(sock_kerb5, &rfds)) {
 	    code = recvfrom(sock_kerb5, packet.data, sizeof(packet.data), 0,
 			    (struct sockaddr *) &packet.from, &fromLen);
 	    if (code < 0) {
+		if (errno == EAGAIN || errno == ECONNREFUSED) 
+		    continue;
 		perror ("calling recvfrom");
 		break;
 	    }
@@ -811,6 +816,15 @@ static SocketListener ()
 	    process_udp_request (sock_kerb5, &packet);
 	} 
     }
+    if (sock_kerb >= 0) {
+	close(sock_kerb);
+	sock_kerb = -1;
+    }
+    if (sock_kerb5 >= 0) {
+	close(sock_kerb5);
+	sock_kerb5 = -1;
+    }
+    printf("UDP SocketListener exiting due to error\n");
 }
 
 #if MAIN
diff --git a/src/rx/rx_lwp.c b/src/rx/rx_lwp.c
index 2daed73527..0e6ffb557b 100644
--- a/src/rx/rx_lwp.c
+++ b/src/rx/rx_lwp.c
@@ -431,7 +431,9 @@ int rxi_Sendmsg(osi_socket socket, struct msghdr *msg_p, int flags)
 #elif defined(AFS_LINUX22_ENV)
 	  /* linux unfortunately returns ECONNREFUSED if the target port
 	   * is no longer in use */
-	if (errno != EWOULDBLOCK && errno != ENOBUFS && errno != ECONNREFUSED)
+	  /* and EAGAIN if a UDP checksum is incorrect */
+	if (errno != EWOULDBLOCK && errno != ENOBUFS &&
+	    errno != ECONNREFUSED && errno != EAGAIN)
 #else
 	if (errno != EWOULDBLOCK && errno != ENOBUFS)
 #endif
diff --git a/src/rx/rx_pthread.c b/src/rx/rx_pthread.c
index a2b7297c99..295913f24d 100644
--- a/src/rx/rx_pthread.c
+++ b/src/rx/rx_pthread.c
@@ -403,7 +403,8 @@ rxi_Sendmsg(socket, msg_p, flags)
 #ifdef AFS_LINUX22_ENV
     /* linux unfortunately returns ECONNREFUSED if the target port
      * is no longer in use */
-    if (ret == -1 && errno != ECONNREFUSED) {
+    /* and EAGAIN if a UDP checksum is incorrect */
+    if (ret == -1 && errno != ECONNREFUSED && errno != EAGAIN) {
 #else
     if (ret == -1) {
 #endif