From: Ondřej Surý <ondrej@isc.org>
Date: Tue, 20 Aug 2024 09:48:04 +0000 (+0200)
Subject: Assume IPV6_V6ONLY is universally available
X-Git-Tag: v9.21.3~9^2~4
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5b273b5726d98d98d53420fdd6d7b899ca92c0d4;p=thirdparty%2Fbind9.git

Assume IPV6_V6ONLY is universally available

In 2024, IPV6_V6ONLY socket option is either available or the operating
system is just not going to be supported.
---

diff --git a/lib/isc/include/isc/net.h b/lib/isc/include/isc/net.h
index eda799c60d2..322584c3af3 100644
--- a/lib/isc/include/isc/net.h
+++ b/lib/isc/include/isc/net.h
@@ -211,18 +211,6 @@ isc_net_probeipv6(void);
  *\li	#ISC_R_UNEXPECTED
  */
 
-isc_result_t
-isc_net_probe_ipv6only(void);
-/*%<
- * Check if the system's kernel supports the IPV6_V6ONLY socket option.
- *
- * Returns:
- *
- *\li	#ISC_R_SUCCESS		the option is supported for both TCP and UDP.
- *\li	#ISC_R_NOTFOUND		IPv6 itself or the option is not supported.
- *\li	#ISC_R_UNEXPECTED
- */
-
 isc_result_t
 isc_net_probe_ipv6pktinfo(void);
 /*
diff --git a/lib/isc/net.c b/lib/isc/net.c
index adae0fef83e..d0ab37316bc 100644
--- a/lib/isc/net.c
+++ b/lib/isc/net.c
@@ -89,7 +89,6 @@
 
 #endif /* HAVE_SYSCTLBYNAME */
 
-static isc_once_t once_ipv6only = ISC_ONCE_INIT;
 #ifdef __notyet__
 static isc_once_t once_ipv6pktinfo = ISC_ONCE_INIT;
 #endif /* ifdef __notyet__ */
@@ -106,7 +105,6 @@ static isc_once_t once = ISC_ONCE_INIT;
 
 static isc_result_t ipv4_result = ISC_R_NOTFOUND;
 static isc_result_t ipv6_result = ISC_R_NOTFOUND;
-static isc_result_t ipv6only_result = ISC_R_NOTFOUND;
 static isc_result_t ipv6pktinfo_result = ISC_R_NOTFOUND;
 
 static isc_result_t
@@ -200,66 +198,6 @@ isc_net_probeipv6(void) {
 	return ipv6_result;
 }
 
-static void
-try_ipv6only(void) {
-#ifdef IPV6_V6ONLY
-	int s, on;
-#endif /* ifdef IPV6_V6ONLY */
-	isc_result_t result;
-
-	result = isc_net_probeipv6();
-	if (result != ISC_R_SUCCESS) {
-		ipv6only_result = result;
-		return;
-	}
-
-#ifndef IPV6_V6ONLY
-	ipv6only_result = ISC_R_NOTFOUND;
-	return;
-#else  /* ifndef IPV6_V6ONLY */
-	/* check for TCP sockets */
-	s = socket(PF_INET6, SOCK_STREAM, 0);
-	if (s == -1) {
-		UNEXPECTED_SYSERROR(errno, "socket()");
-		ipv6only_result = ISC_R_UNEXPECTED;
-		return;
-	}
-
-	on = 1;
-	if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0) {
-		ipv6only_result = ISC_R_NOTFOUND;
-		goto close;
-	}
-
-	close(s);
-
-	/* check for UDP sockets */
-	s = socket(PF_INET6, SOCK_DGRAM, 0);
-	if (s == -1) {
-		UNEXPECTED_SYSERROR(errno, "socket()");
-		ipv6only_result = ISC_R_UNEXPECTED;
-		return;
-	}
-
-	on = 1;
-	if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0) {
-		ipv6only_result = ISC_R_NOTFOUND;
-		goto close;
-	}
-
-	ipv6only_result = ISC_R_SUCCESS;
-
-close:
-	close(s);
-	return;
-#endif /* IPV6_V6ONLY */
-}
-
-static void
-initialize_ipv6only(void) {
-	isc_once_do(&once_ipv6only, try_ipv6only);
-}
-
 #ifdef __notyet__
 static void
 try_ipv6pktinfo(void) {
@@ -305,12 +243,6 @@ initialize_ipv6pktinfo(void) {
 }
 #endif /* ifdef __notyet__ */
 
-isc_result_t
-isc_net_probe_ipv6only(void) {
-	initialize_ipv6only();
-	return ipv6only_result;
-}
-
 isc_result_t
 isc_net_probe_ipv6pktinfo(void) {
 /*
diff --git a/lib/ns/interfacemgr.c b/lib/ns/interfacemgr.c
index 836ee05a853..7902b1a0da9 100644
--- a/lib/ns/interfacemgr.c
+++ b/lib/ns/interfacemgr.c
@@ -1085,7 +1085,6 @@ do_scan(ns_interfacemgr_t *mgr, bool verbose, bool config) {
 	isc_interfaceiter_t *iter = NULL;
 	bool scan_ipv4 = false;
 	bool scan_ipv6 = false;
-	bool ipv6only = true;
 	bool ipv6pktinfo = true;
 	isc_result_t result;
 	isc_netaddr_t zero_address, zero_address6;
@@ -1124,15 +1123,11 @@ do_scan(ns_interfacemgr_t *mgr, bool verbose, bool config) {
 	 * packets as the form of mapped addresses unintentionally
 	 * unless explicitly allowed.
 	 */
-	if (scan_ipv6 && isc_net_probe_ipv6only() != ISC_R_SUCCESS) {
-		ipv6only = false;
-		log_explicit = true;
-	}
 	if (scan_ipv6 && isc_net_probe_ipv6pktinfo() != ISC_R_SUCCESS) {
 		ipv6pktinfo = false;
 		log_explicit = true;
 	}
-	if (scan_ipv6 && ipv6only && ipv6pktinfo) {
+	if (scan_ipv6 && ipv6pktinfo) {
 		for (le = ISC_LIST_HEAD(mgr->listenon6->elts); le != NULL;
 		     le = ISC_LIST_NEXT(le, link))
 		{
@@ -1283,7 +1278,7 @@ do_scan(ns_interfacemgr_t *mgr, bool verbose, bool config) {
 			 * The case of "any" IPv6 address will require
 			 * special considerations later, so remember it.
 			 */
-			if (family == AF_INET6 && ipv6only && ipv6pktinfo &&
+			if (family == AF_INET6 && ipv6pktinfo &&
 			    listenon_is_ip6_any(le))
 			{
 				ipv6_wildcard = true;