From a70cd026df05d4085545860f05f6b93618f594ad Mon Sep 17 00:00:00 2001
From: Evan Hunt <each@isc.org>
Date: Thu, 1 Apr 2021 14:02:03 -0700
Subject: [PATCH] move UDP connect retries from dig into isc_nm_udpconnect()

dig previously ran isc_nm_udpconnect() three times before giving
up, to work around a freebsd bug that caused connect() to return
a spurious transient EADDRINUSE. this commit moves the retry code
into the network manager itself, so that isc_nm_udpconnect() no
longer needs to return a result code.
---
 bin/dig/dighost.c    | 50 +++++++++++++-------------------------------
 bin/dig/dighost.h    |  1 -
 lib/isc/netmgr/udp.c | 11 +++++++++-
 3 files changed, 25 insertions(+), 37 deletions(-)

diff --git a/bin/dig/dighost.c b/bin/dig/dighost.c
index 9d8a1e5a22..3ec72f96f7 100644
--- a/bin/dig/dighost.c
+++ b/bin/dig/dighost.c
@@ -2794,12 +2794,11 @@ start_tcp(dig_query_t *query) {
 		if (query->lookup->tls_mode) {
 			result = isc_tlsctx_createclient(&query->tlsctx);
 			RUNTIME_CHECK(result == ISC_R_SUCCESS);
-			result = isc_nm_tlsdnsconnect(
-				netmgr, (isc_nmiface_t *)&localaddr,
-				(isc_nmiface_t *)&query->sockaddr,
-				tcp_connected, query, local_timeout, 0,
-				query->tlsctx);
-			check_result(result, "isc_nm_tlsdnsconnect");
+			isc_nm_tlsdnsconnect(netmgr,
+					     (isc_nmiface_t *)&localaddr,
+					     (isc_nmiface_t *)&query->sockaddr,
+					     tcp_connected, query,
+					     local_timeout, 0, query->tlsctx);
 		} else if (query->lookup->https_mode) {
 			char uri[4096] = { 0 };
 			snprintf(uri, sizeof(uri), "https://%s:%u%s",
@@ -2814,18 +2813,16 @@ start_tcp(dig_query_t *query) {
 					query->tlsctx);
 			}
 
-			result = isc_nm_httpconnect(
-				netmgr, (isc_nmiface_t *)&localaddr,
-				(isc_nmiface_t *)&query->sockaddr, uri,
-				!query->lookup->https_get, tcp_connected, query,
-				query->tlsctx, local_timeout, 0);
-			check_result(result, "isc_nm_httpconnect");
+			isc_nm_httpconnect(netmgr, (isc_nmiface_t *)&localaddr,
+					   (isc_nmiface_t *)&query->sockaddr,
+					   uri, !query->lookup->https_get,
+					   tcp_connected, query, query->tlsctx,
+					   local_timeout, 0);
 		} else {
-			result = isc_nm_tcpdnsconnect(
+			isc_nm_tcpdnsconnect(
 				netmgr, (isc_nmiface_t *)&localaddr,
 				(isc_nmiface_t *)&query->sockaddr,
 				tcp_connected, query, local_timeout, 0);
-			check_result(result, "isc_nm_tcpdnsconnect");
 		}
 
 		/* XXX: set DSCP */
@@ -2904,9 +2901,7 @@ udp_ready(isc_nmhandle_t *handle, isc_result_t eresult, void *arg) {
 			debug("udp setup failed: %s",
 			      isc_result_totext(eresult));
 		}
-		if (query->tries == 0) {
-			query_detach(&query);
-		}
+		query_detach(&query);
 		return;
 	}
 
@@ -2993,24 +2988,9 @@ start_udp(dig_query_t *query) {
 		}
 	}
 
-	query->tries = 3;
-	do {
-		int local_timeout = timeout * 1000;
-		if (local_timeout == 0) {
-			local_timeout = UDP_TIMEOUT * 1000;
-		}
-
-		/*
-		 * On FreeBSD the UDP connect() call sometimes results
-		 * in a spurious transient EADDRINUSE. Try a few more times
-		 * before giving up.
-		 */
-		debug("isc_nm_udpconnect(): %d tries left", --query->tries);
-		result = isc_nm_udpconnect(netmgr, (isc_nmiface_t *)&localaddr,
-					   (isc_nmiface_t *)&query->sockaddr,
-					   udp_ready, query, local_timeout, 0);
-	} while (result != ISC_R_SUCCESS && query->tries > 0);
-	check_result(result, "isc_nm_udpconnect");
+	isc_nm_udpconnect(netmgr, (isc_nmiface_t *)&localaddr,
+			  (isc_nmiface_t *)&query->sockaddr, udp_ready, query,
+			  (timeout ? timeout : UDP_TIMEOUT) * 1000, 0);
 }
 
 /*%
diff --git a/bin/dig/dighost.h b/bin/dig/dighost.h
index 0dfeb56da5..8da437625b 100644
--- a/bin/dig/dighost.h
+++ b/bin/dig/dighost.h
@@ -208,7 +208,6 @@ struct dig_query {
 	isc_time_t time_recv;
 	uint64_t byte_count;
 	isc_timer_t *timer;
-	uint8_t tries;
 	isc_tlsctx_t *tlsctx;
 };
 
diff --git a/lib/isc/netmgr/udp.c b/lib/isc/netmgr/udp.c
index 843be0b6ac..9485fb76d5 100644
--- a/lib/isc/netmgr/udp.c
+++ b/lib/isc/netmgr/udp.c
@@ -597,6 +597,7 @@ udp_connect_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req) {
 	isc__networker_t *worker = NULL;
 	int uv_bind_flags = UV_UDP_REUSEADDR;
 	isc_result_t result = ISC_R_DEFAULT;
+	int tries = 3;
 	int r;
 
 	REQUIRE(isc__nm_in_netthread());
@@ -642,7 +643,15 @@ udp_connect_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req) {
 			    &(int){ ISC_SEND_BUFFER_SIZE });
 #endif
 
-	r = isc_uv_udp_connect(&sock->uv_handle.udp, &req->peer.type.sa);
+	/*
+	 * On FreeBSD the UDP connect() call sometimes results in a
+	 * spurious transient EADDRINUSE. Try a few more times before
+	 * giving up.
+	 */
+	do {
+		r = isc_uv_udp_connect(&sock->uv_handle.udp,
+				       &req->peer.type.sa);
+	} while (r == UV_EADDRINUSE && --tries > 0);
 	if (r != 0) {
 		isc__nm_incstats(sock->mgr,
 				 sock->statsindex[STATID_CONNECTFAIL]);