Assume that IPv4 and IPv6 is always available

In 2024, it is reasonable to assume that IPv4 and IPv6 is always
available on a socket() level.  We still keep the option to enable or
disable each IP version individually, as the routing might be broken or
undesirable for one of the versions.

diff --git a/lib/isc/include/isc/net.h b/lib/isc/include/isc/net.h
index 322584c3af3d0e0417fd4c9c95af5dc28c0ad548..7d04bfe6b07e48d49dc82d79be3f35878b8db1d4 100644 (file)
--- a/lib/isc/include/isc/net.h
+++ b/lib/isc/include/isc/net.h
@@ -188,27 +188,23 @@ ISC_LANG_BEGINDECLS
 isc_result_t
 isc_net_probeipv4(void);
 /*%<
- * Check if the system's kernel supports IPv4.
+ * Check if the IPv4 has been disabled.
  *
  * Returns:
  *
  *\li  #ISC_R_SUCCESS          IPv4 is supported.
- *\li  #ISC_R_NOTFOUND         IPv4 is not supported.
  *\li  #ISC_R_DISABLED         IPv4 is disabled.
- *\li  #ISC_R_UNEXPECTED
  */
 
 isc_result_t
 isc_net_probeipv6(void);
 /*%<
- * Check if the system's kernel supports IPv6.
+ * Check if the IPv6 has been disabled.
  *
  * Returns:
  *
  *\li  #ISC_R_SUCCESS          IPv6 is supported.
- *\li  #ISC_R_NOTFOUND         IPv6 is not supported.
  *\li  #ISC_R_DISABLED         IPv6 is disabled.
- *\li  #ISC_R_UNEXPECTED
  */
 
 isc_result_t

diff --git a/lib/isc/net.c b/lib/isc/net.c
index d0ab37316bc70e4fa692fedc8ad90bcd84b3c6c4..8f73185696f3d50ae8b4b7dcaa1859c4baef680b 100644 (file)
--- a/lib/isc/net.c
+++ b/lib/isc/net.c
@@ -101,100 +101,17 @@ static isc_once_t once_ipv6pktinfo = ISC_ONCE_INIT;
 #endif /* ! __APPLE__ */
 #endif /* ! ISC_CMSG_IP_TOS */
 
-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 ipv4_result = ISC_R_SUCCESS;
+static isc_result_t ipv6_result = ISC_R_SUCCESS;
 static isc_result_t ipv6pktinfo_result = ISC_R_NOTFOUND;
 
-static isc_result_t
-try_proto(int domain) {
-       int s;
-       isc_result_t result = ISC_R_SUCCESS;
-
-       s = socket(domain, SOCK_STREAM, 0);
-       if (s == -1) {
-               switch (errno) {
-#ifdef EAFNOSUPPORT
-               case EAFNOSUPPORT:
-#endif /* ifdef EAFNOSUPPORT */
-#ifdef EPFNOSUPPORT
-               case EPFNOSUPPORT:
-#endif /* ifdef EPFNOSUPPORT */
-#ifdef EPROTONOSUPPORT
-               case EPROTONOSUPPORT:
-#endif /* ifdef EPROTONOSUPPORT */
-#ifdef EINVAL
-               case EINVAL:
-#endif /* ifdef EINVAL */
-                       return ISC_R_NOTFOUND;
-               default:
-                       UNEXPECTED_SYSERROR(errno, "socket()");
-                       return ISC_R_UNEXPECTED;
-               }
-       }
-
-       if (domain == PF_INET6) {
-               struct sockaddr_in6 sin6;
-               unsigned int len;
-
-               /*
-                * Check to see if IPv6 is broken, as is common on Linux.
-                */
-               len = sizeof(sin6);
-               if (getsockname(s, (struct sockaddr *)&sin6, (void *)&len) < 0)
-               {
-                       isc_log_write(ISC_LOGCATEGORY_GENERAL,
-                                     ISC_LOGMODULE_SOCKET, ISC_LOG_ERROR,
-                                     "retrieving the address of an IPv6 "
-                                     "socket from the kernel failed.");
-                       isc_log_write(ISC_LOGCATEGORY_GENERAL,
-                                     ISC_LOGMODULE_SOCKET, ISC_LOG_ERROR,
-                                     "IPv6 is not supported.");
-                       result = ISC_R_NOTFOUND;
-               } else {
-                       if (len == sizeof(struct sockaddr_in6)) {
-                               result = ISC_R_SUCCESS;
-                       } else {
-                               isc_log_write(ISC_LOGCATEGORY_GENERAL,
-                                             ISC_LOGMODULE_SOCKET,
-                                             ISC_LOG_ERROR,
-                                             "IPv6 structures in kernel and "
-                                             "user space do not match.");
-                               isc_log_write(ISC_LOGCATEGORY_GENERAL,
-                                             ISC_LOGMODULE_SOCKET,
-                                             ISC_LOG_ERROR,
-                                             "IPv6 is not supported.");
-                               result = ISC_R_NOTFOUND;
-                       }
-               }
-       }
-
-       (void)close(s);
-
-       return result;
-}
-
-static void
-initialize_action(void) {
-       ipv4_result = try_proto(PF_INET);
-       ipv6_result = try_proto(PF_INET6);
-}
-
-static void
-initialize(void) {
-       isc_once_do(&once, initialize_action);
-}
-
 isc_result_t
 isc_net_probeipv4(void) {
-       initialize();
        return ipv4_result;
 }
 
 isc_result_t
 isc_net_probeipv6(void) {
-       initialize();
        return ipv6_result;
 }
 
@@ -382,7 +299,6 @@ isc_net_getudpportrange(int af, in_port_t *low, in_port_t *high) {
 
 void
 isc_net_disableipv4(void) {
-       initialize();
        if (ipv4_result == ISC_R_SUCCESS) {
                ipv4_result = ISC_R_DISABLED;
        }
@@ -390,7 +306,6 @@ isc_net_disableipv4(void) {
 
 void
 isc_net_disableipv6(void) {
-       initialize();
        if (ipv6_result == ISC_R_SUCCESS) {
                ipv6_result = ISC_R_DISABLED;
        }
@@ -398,7 +313,6 @@ isc_net_disableipv6(void) {
 
 void
 isc_net_enableipv4(void) {
-       initialize();
        if (ipv4_result == ISC_R_DISABLED) {
                ipv4_result = ISC_R_SUCCESS;
        }
@@ -406,7 +320,6 @@ isc_net_enableipv4(void) {
 
 void
 isc_net_enableipv6(void) {
-       initialize();
        if (ipv6_result == ISC_R_DISABLED) {
                ipv6_result = ISC_R_SUCCESS;
        }