Remove configure probe for sockaddr_in6 and require AF_INET6.

SUSv3 <netinet/in.h> defines struct sockaddr_in6, and all targeted Unix
systems have it.  Windows has it in <ws2ipdef.h>.  Remove the configure
probe, the macro and a small amount of dead code.

Also remove a mention of IPv6-less builds from the documentation, since
there aren't any.

This is similar to commits f5580882 and 077bf2f2 for Unix sockets.  Even
though AF_INET6 is an "optional" component of SUSv3, there are no known
modern operating system without it, and it seems even less likely to be
omitted from future systems than AF_UNIX.

Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CA+hUKGKErNfhmvb_H0UprEmp4LPzGN06yR2_0tYikjzB-2ECMw@mail.gmail.com

6 files changed, 3 insertions, 64 deletions

diff --git a/src/backend/libpq/auth.c b/src/backend/libpq/auth.c
index 10cd19e6cd9..b2b0b83a97b 100644
--- a/src/backend/libpq/auth.c
+++ b/src/backend/libpq/auth.c
@@ -3015,13 +3015,8 @@ PerformRadiusTransaction(const char *server, const char *secret, const char *por
 	int			packetlength;
 	pgsocket	sock;
 
-#ifdef HAVE_IPV6
 	struct sockaddr_in6 localaddr;
 	struct sockaddr_in6 remoteaddr;
-#else
-	struct sockaddr_in localaddr;
-	struct sockaddr_in remoteaddr;
-#endif
 	struct addrinfo hint;
 	struct addrinfo *serveraddrs;
 	int			port;
@@ -3131,18 +3126,12 @@ PerformRadiusTransaction(const char *server, const char *secret, const char *por
 	}
 
 	memset(&localaddr, 0, sizeof(localaddr));
-#ifdef HAVE_IPV6
 	localaddr.sin6_family = serveraddrs[0].ai_family;
 	localaddr.sin6_addr = in6addr_any;
 	if (localaddr.sin6_family == AF_INET6)
 		addrsize = sizeof(struct sockaddr_in6);
 	else
 		addrsize = sizeof(struct sockaddr_in);
-#else
-	localaddr.sin_family = serveraddrs[0].ai_family;
-	localaddr.sin_addr.s_addr = INADDR_ANY;
-	addrsize = sizeof(struct sockaddr_in);
-#endif
 
 	if (bind(sock, (struct sockaddr *) &localaddr, addrsize))
 	{
@@ -3245,21 +3234,11 @@ PerformRadiusTransaction(const char *server, const char *secret, const char *por
 			return STATUS_ERROR;
 		}
 
-#ifdef HAVE_IPV6
 		if (remoteaddr.sin6_port != pg_hton16(port))
-#else
-		if (remoteaddr.sin_port != pg_hton16(port))
-#endif
 		{
-#ifdef HAVE_IPV6
 			ereport(LOG,
 					(errmsg("RADIUS response from %s was sent from incorrect port: %d",
 							server, pg_ntoh16(remoteaddr.sin6_port))));
-#else
-			ereport(LOG,
-					(errmsg("RADIUS response from %s was sent from incorrect port: %d",
-							server, pg_ntoh16(remoteaddr.sin_port))));
-#endif
 			continue;
 		}
 
diff --git a/src/backend/libpq/hba.c b/src/backend/libpq/hba.c
index 1447588c4ae..8f2b8c6b03a 100644
--- a/src/backend/libpq/hba.c
+++ b/src/backend/libpq/hba.c
@@ -645,8 +645,6 @@ ipv4eq(struct sockaddr_in *a, struct sockaddr_in *b)
 	return (a->sin_addr.s_addr == b->sin_addr.s_addr);
 }
 
-#ifdef HAVE_IPV6
-
 static bool
 ipv6eq(struct sockaddr_in6 *a, struct sockaddr_in6 *b)
 {
@@ -658,7 +656,6 @@ ipv6eq(struct sockaddr_in6 *a, struct sockaddr_in6 *b)
 
 	return true;
 }
-#endif							/* HAVE_IPV6 */
 
 /*
  * Check whether host name matches pattern.
@@ -747,7 +744,6 @@ check_hostname(hbaPort *port, const char *hostname)
 					break;
 				}
 			}
-#ifdef HAVE_IPV6
 			else if (gai->ai_addr->sa_family == AF_INET6)
 			{
 				if (ipv6eq((struct sockaddr_in6 *) gai->ai_addr,
@@ -757,7 +753,6 @@ check_hostname(hbaPort *port, const char *hostname)
 					break;
 				}
 			}
-#endif
 		}
 	}
 
diff --git a/src/backend/libpq/ifaddr.c b/src/backend/libpq/ifaddr.c
index de35fbba455..ff9dadfb379 100644
--- a/src/backend/libpq/ifaddr.c
+++ b/src/backend/libpq/ifaddr.c
@@ -34,11 +34,9 @@ static int	range_sockaddr_AF_INET(const struct sockaddr_in *addr,
 								   const struct sockaddr_in *netaddr,
 								   const struct sockaddr_in *netmask);
 
-#ifdef HAVE_IPV6
 static int	range_sockaddr_AF_INET6(const struct sockaddr_in6 *addr,
 									const struct sockaddr_in6 *netaddr,
 									const struct sockaddr_in6 *netmask);
-#endif
 
 
 /*
@@ -56,12 +54,10 @@ pg_range_sockaddr(const struct sockaddr_storage *addr,
 		return range_sockaddr_AF_INET((const struct sockaddr_in *) addr,
 									  (const struct sockaddr_in *) netaddr,
 									  (const struct sockaddr_in *) netmask);
-#ifdef HAVE_IPV6
 	else if (addr->ss_family == AF_INET6)
 		return range_sockaddr_AF_INET6((const struct sockaddr_in6 *) addr,
 									   (const struct sockaddr_in6 *) netaddr,
 									   (const struct sockaddr_in6 *) netmask);
-#endif
 	else
 		return 0;
 }
@@ -78,9 +74,6 @@ range_sockaddr_AF_INET(const struct sockaddr_in *addr,
 		return 0;
 }
 
-
-#ifdef HAVE_IPV6
-
 static int
 range_sockaddr_AF_INET6(const struct sockaddr_in6 *addr,
 						const struct sockaddr_in6 *netaddr,
@@ -97,7 +90,6 @@ range_sockaddr_AF_INET6(const struct sockaddr_in6 *addr,
 
 	return 1;
 }
-#endif							/* HAVE_IPV6 */
 
 /*
  *	pg_sockaddr_cidr_mask - make a network mask of the appropriate family
@@ -147,7 +139,6 @@ pg_sockaddr_cidr_mask(struct sockaddr_storage *mask, char *numbits, int family)
 				break;
 			}
 
-#ifdef HAVE_IPV6
 		case AF_INET6:
 			{
 				struct sockaddr_in6 mask6;
@@ -172,7 +163,7 @@ pg_sockaddr_cidr_mask(struct sockaddr_storage *mask, char *numbits, int family)
 				memcpy(mask, &mask6, sizeof(mask6));
 				break;
 			}
-#endif
+
 		default:
 			return -1;
 	}
@@ -207,13 +198,11 @@ run_ifaddr_callback(PgIfAddrCallback callback, void *cb_data,
 			if (((struct sockaddr_in *) mask)->sin_addr.s_addr == INADDR_ANY)
 				mask = NULL;
 		}
-#ifdef HAVE_IPV6
 		else if (mask->sa_family == AF_INET6)
 		{
 			if (IN6_IS_ADDR_UNSPECIFIED(&((struct sockaddr_in6 *) mask)->sin6_addr))
 				mask = NULL;
 		}
-#endif
 	}
 
 	/* If mask is invalid, generate our own fully-set mask */
@@ -437,10 +426,7 @@ pg_foreach_ifaddr(PgIfAddrCallback callback, void *cb_data)
 {
 	struct sockaddr_in addr;
 	struct sockaddr_storage mask;
-
-#ifdef HAVE_IPV6
 	struct sockaddr_in6 addr6;
-#endif
 
 	/* addr 127.0.0.1/8 */
 	memset(&addr, 0, sizeof(addr));
@@ -452,7 +438,6 @@ pg_foreach_ifaddr(PgIfAddrCallback callback, void *cb_data)
 						(struct sockaddr *) &addr,
 						(struct sockaddr *) &mask);
 
-#ifdef HAVE_IPV6
 	/* addr ::1/128 */
 	memset(&addr6, 0, sizeof(addr6));
 	addr6.sin6_family = AF_INET6;
@@ -462,7 +447,6 @@ pg_foreach_ifaddr(PgIfAddrCallback callback, void *cb_data)
 	run_ifaddr_callback(callback, cb_data,
 						(struct sockaddr *) &addr6,
 						(struct sockaddr *) &mask);
-#endif
 
 	return 0;
 }
diff --git a/src/backend/libpq/pqcomm.c b/src/backend/libpq/pqcomm.c
index 7112e9751b1..cba0caced73 100644
--- a/src/backend/libpq/pqcomm.c
+++ b/src/backend/libpq/pqcomm.c
@@ -413,11 +413,9 @@ StreamServerPort(int family, const char *hostName, unsigned short portNumber,
 			case AF_INET:
 				familyDesc = _("IPv4");
 				break;
-#ifdef HAVE_IPV6
 			case AF_INET6:
 				familyDesc = _("IPv6");
 				break;
-#endif
 			case AF_UNIX:
 				familyDesc = _("Unix");
 				break;
diff --git a/src/backend/utils/adt/network.c b/src/backend/utils/adt/network.c
index ea1c7390d0d..6d580ea78f6 100644
--- a/src/backend/utils/adt/network.c
+++ b/src/backend/utils/adt/network.c
@@ -1725,9 +1725,7 @@ inet_client_addr(PG_FUNCTION_ARGS)
 	switch (port->raddr.addr.ss_family)
 	{
 		case AF_INET:
-#ifdef HAVE_IPV6
 		case AF_INET6:
-#endif
 			break;
 		default:
 			PG_RETURN_NULL();
@@ -1764,9 +1762,7 @@ inet_client_port(PG_FUNCTION_ARGS)
 	switch (port->raddr.addr.ss_family)
 	{
 		case AF_INET:
-#ifdef HAVE_IPV6
 		case AF_INET6:
-#endif
 			break;
 		default:
 			PG_RETURN_NULL();
@@ -1801,9 +1797,7 @@ inet_server_addr(PG_FUNCTION_ARGS)
 	switch (port->laddr.addr.ss_family)
 	{
 		case AF_INET:
-#ifdef HAVE_IPV6
 		case AF_INET6:
-#endif
 			break;
 		default:
 			PG_RETURN_NULL();
@@ -1840,9 +1834,7 @@ inet_server_port(PG_FUNCTION_ARGS)
 	switch (port->laddr.addr.ss_family)
 	{
 		case AF_INET:
-#ifdef HAVE_IPV6
 		case AF_INET6:
-#endif
 			break;
 		default:
 			PG_RETURN_NULL();
@@ -2102,7 +2094,6 @@ inetmi(PG_FUNCTION_ARGS)
 void
 clean_ipv6_addr(int addr_family, char *addr)
 {
-#ifdef HAVE_IPV6
 	if (addr_family == AF_INET6)
 	{
 		char	   *pct = strchr(addr, '%');
@@ -2110,5 +2101,4 @@ clean_ipv6_addr(int addr_family, char *addr)
 		if (pct)
 			*pct = '\0';
 	}
-#endif
 }
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index d9e2a793829..4cca30aae7c 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -735,11 +735,8 @@ pg_stat_get_activity(PG_FUNCTION_ARGS)
 			}
 			else
 			{
-				if (beentry->st_clientaddr.addr.ss_family == AF_INET
-#ifdef HAVE_IPV6
-					|| beentry->st_clientaddr.addr.ss_family == AF_INET6
-#endif
-					)
+				if (beentry->st_clientaddr.addr.ss_family == AF_INET ||
+					beentry->st_clientaddr.addr.ss_family == AF_INET6)
 				{
 					char		remote_host[NI_MAXHOST];
 					char		remote_port[NI_MAXSERV];
@@ -1105,9 +1102,7 @@ pg_stat_get_backend_client_addr(PG_FUNCTION_ARGS)
 	switch (beentry->st_clientaddr.addr.ss_family)
 	{
 		case AF_INET:
-#ifdef HAVE_IPV6
 		case AF_INET6:
-#endif
 			break;
 		default:
 			PG_RETURN_NULL();
@@ -1152,9 +1147,7 @@ pg_stat_get_backend_client_port(PG_FUNCTION_ARGS)
 	switch (beentry->st_clientaddr.addr.ss_family)
 	{
 		case AF_INET:
-#ifdef HAVE_IPV6
 		case AF_INET6:
-#endif
 			break;
 		case AF_UNIX:
 			PG_RETURN_INT32(-1);