dns/unbound: Fix loop when ENOBUFS is returned

- Fix send of udp retries when ENOBUFS is returned. It stops looping
  and also waits for the condition to go away. Reported to upstream
  by Florian Obser.

PR:             274352, 274446
Approved by:	jaap@NLnetLabs.nl (maintainer)
MFH:		2023Q4

2 files changed, 160 insertions, 0 deletions

diff --git a/dns/unbound/Makefile b/dns/unbound/Makefile
index 7697561bdef2..b3ba87493a1e 100644
--- a/dns/unbound/Makefile
+++ b/dns/unbound/Makefile
@@ -1,5 +1,6 @@
 PORTNAME=	unbound
 DISTVERSION=	1.18.0
+PORTREVISION=	1
 CATEGORIES=	dns
 MASTER_SITES=	https://www.nlnetlabs.nl/downloads/unbound/
 
diff --git a/dns/unbound/files/patch-netevent.c b/dns/unbound/files/patch-netevent.c
new file mode 100644
index 000000000000..e94ab49defa1
--- /dev/null
+++ b/dns/unbound/files/patch-netevent.c
@@ -0,0 +1,159 @@
+--- util/netevent.c.orig	2023-08-30 01:01:13.000000000 -0700
++++ util/netevent.c	2023-10-12 19:00:53.157995000 -0700
+@@ -116,6 +116,8 @@
+ 
+ /** timeout in millisec to wait for write to unblock, packets dropped after.*/
+ #define SEND_BLOCKED_WAIT_TIMEOUT 200
++/** max number of times to wait for write to unblock, packets dropped after.*/
++#define SEND_BLOCKED_MAX_RETRY 5
+ 
+ /** Let's make timestamping code cleaner and redefine SO_TIMESTAMP* */
+ #ifndef SO_TIMESTAMP
+@@ -402,9 +404,10 @@
+ 			WSAGetLastError() == WSAENOBUFS ||
+ 			WSAGetLastError() == WSAEWOULDBLOCK) {
+ #endif
++			int retries = 0;
+ 			/* if we set the fd blocking, other threads suddenly
+ 			 * have a blocking fd that they operate on */
+-			while(sent == -1 && (
++			while(sent == -1 && retries < SEND_BLOCKED_MAX_RETRY && (
+ #ifndef USE_WINSOCK
+ 				errno == EAGAIN || errno == EINTR ||
+ #  ifdef EWOULDBLOCK
+@@ -419,6 +422,13 @@
+ #endif
+ 			)) {
+ #if defined(HAVE_POLL) || defined(USE_WINSOCK)
++				int send_nobufs = (
++#ifndef USE_WINSOCK
++					errno == ENOBUFS
++#else
++					WSAGetLastError() == WSAENOBUFS
++#endif
++				);
+ 				struct pollfd p;
+ 				int pret;
+ 				memset(&p, 0, sizeof(p));
+@@ -457,8 +467,48 @@
+ 					log_err("poll udp out failed: %s",
+ 						sock_strerror(errno));
+ 					return 0;
++				} else if((pret < 0 &&
++#ifndef USE_WINSOCK
++					errno == ENOBUFS
++#else
++					WSAGetLastError() == WSAENOBUFS
++#endif
++					) || (send_nobufs && retries > 0)) {
++					/* ENOBUFS, and poll returned without
++					 * a timeout. Or the retried send call
++					 * returned ENOBUFS. It is good to
++					 * wait a bit for the error to clear. */
++					/* The timeout is 20*(2^(retries+1)),
++					 * it increases exponentially, starting
++					 * at 40 msec. After 5 tries, 1240 msec
++					 * have passed in total, when poll
++					 * returned the error, and 1200 msec
++					 * when send returned the errors. */
++#ifndef USE_WINSOCK
++					pret = poll(NULL, 0, (SEND_BLOCKED_WAIT_TIMEOUT/10)<<(retries+1));
++#else
++					pret = WSAPoll(NULL, 0, (SEND_BLOCKED_WAIT_TIMEOUT/10)<<(retries+1));
++#endif
++					if(pret < 0 &&
++#ifndef USE_WINSOCK
++						errno != EAGAIN && errno != EINTR &&
++#  ifdef EWOULDBLOCK
++						errno != EWOULDBLOCK &&
++#  endif
++						errno != ENOBUFS
++#else
++						WSAGetLastError() != WSAEINPROGRESS &&
++						WSAGetLastError() != WSAEINTR &&
++						WSAGetLastError() != WSAENOBUFS &&
++						WSAGetLastError() != WSAEWOULDBLOCK
++#endif
++					) {
++						log_err("poll udp out timer failed: %s",
++							sock_strerror(errno));
++					}
+ 				}
+ #endif /* defined(HAVE_POLL) || defined(USE_WINSOCK) */
++				retries++;
+ 				if (!is_connected) {
+ 					sent = sendto(c->fd, (void*)sldns_buffer_begin(packet),
+ 						sldns_buffer_remaining(packet), 0,
+@@ -665,7 +715,8 @@
+ 			WSAGetLastError() == WSAENOBUFS ||
+ 			WSAGetLastError() == WSAEWOULDBLOCK) {
+ #endif
+-			while(sent == -1 && (
++			int retries = 0;
++			while(sent == -1 && retries < SEND_BLOCKED_MAX_RETRY && (
+ #ifndef USE_WINSOCK
+ 				errno == EAGAIN || errno == EINTR ||
+ #  ifdef EWOULDBLOCK
+@@ -680,6 +731,13 @@
+ #endif
+ 			)) {
+ #if defined(HAVE_POLL) || defined(USE_WINSOCK)
++				int send_nobufs = (
++#ifndef USE_WINSOCK
++					errno == ENOBUFS
++#else
++					WSAGetLastError() == WSAENOBUFS
++#endif
++				);
+ 				struct pollfd p;
+ 				int pret;
+ 				memset(&p, 0, sizeof(p));
+@@ -718,8 +776,48 @@
+ 					log_err("poll udp out failed: %s",
+ 						sock_strerror(errno));
+ 					return 0;
++				} else if((pret < 0 &&
++#ifndef USE_WINSOCK
++					errno == ENOBUFS
++#else
++					WSAGetLastError() == WSAENOBUFS
++#endif
++					) || (send_nobufs && retries > 0)) {
++					/* ENOBUFS, and poll returned without
++					 * a timeout. Or the retried send call
++					 * returned ENOBUFS. It is good to
++					 * wait a bit for the error to clear. */
++					/* The timeout is 20*(2^(retries+1)),
++					 * it increases exponentially, starting
++					 * at 40 msec. After 5 tries, 1240 msec
++					 * have passed in total, when poll
++					 * returned the error, and 1200 msec
++					 * when send returned the errors. */
++#ifndef USE_WINSOCK
++					pret = poll(NULL, 0, (SEND_BLOCKED_WAIT_TIMEOUT/10)<<(retries+1));
++#else
++					pret = WSAPoll(NULL, 0, (SEND_BLOCKED_WAIT_TIMEOUT/10)<<(retries+1));
++#endif
++					if(pret < 0 &&
++#ifndef USE_WINSOCK
++						errno != EAGAIN && errno != EINTR &&
++#  ifdef EWOULDBLOCK
++						errno != EWOULDBLOCK &&
++#  endif
++						errno != ENOBUFS
++#else
++						WSAGetLastError() != WSAEINPROGRESS &&
++						WSAGetLastError() != WSAEINTR &&
++						WSAGetLastError() != WSAENOBUFS &&
++						WSAGetLastError() != WSAEWOULDBLOCK
++#endif
++					) {
++						log_err("poll udp out timer failed: %s",
++							sock_strerror(errno));
++					}
+ 				}
+ #endif /* defined(HAVE_POLL) || defined(USE_WINSOCK) */
++				retries++;
+ 				sent = sendmsg(c->fd, &msg, 0);
+ 			}
+ 		}