diff --git a/src/backend/libpq/v6util.c b/src/backend/libpq/v6util.c
new file mode 100644
index 0000000000000000000000000000000000000000..10bab95303ce298f186334b47abd5057f174c4cd
--- /dev/null
+++ b/src/backend/libpq/v6util.c
@@ -0,0 +1,300 @@
+#include "postgres.h"
+
+#include <errno.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#ifdef HAVE_NETINET_TCP_H
+#include <netinet/tcp.h>
+#endif
+#include <arpa/inet.h>
+#include <sys/file.h>
+
+#include "libpq/libpq.h"
+#include "miscadmin.h"
+
+
+
+
+
+
+#ifdef HAVE_UNIX_SOCKETS
+static int ga_unix(const char* path, const struct addrinfo* hintsp,
+ struct addrinfo** result);
+#endif /* HAVE_UNIX_SOCKETS */
+
+
+int getaddrinfo2(const char* hostname, const char* servname,
+ const struct addrinfo* hintp, struct addrinfo **result)
+{
+#ifdef HAVE_UNIX_SOCKETS
+ if( hintp != NULL && hintp->ai_family == AF_UNIX){
+ return ga_unix(servname, hintp, result);
+ }
+ else {
+#endif /* HAVE_UNIX_SOCKETS */
+ return getaddrinfo(hostname, servname, hintp, result);
+#ifdef HAVE_UNIX_SOCKETS
+ }
+#endif /* HAVE_UNIX_SOCKETS */
+}
+
+void freeaddrinfo2(int hint_ai_family, struct addrinfo *ai)
+{
+#ifdef HAVE_UNIX_SOCKETS
+ if(hint_ai_family == AF_UNIX){
+ struct addrinfo *p;
+ while(ai != NULL){
+ p = ai;
+ ai = ai->ai_next;
+ free(p->ai_addr);
+ free(p);
+ }
+ }
+ else {
+#endif /* HAVE_UNIX_SOCKETS */
+ freeaddrinfo(ai);
+#ifdef HAVE_UNIX_SOCKETS
+ }
+#endif /* HAVE_UNIX_SOCKETS */
+}
+
+
+#ifdef HAVE_UNIX_SOCKETS
+/**
+ * Bug: only one addrinfo is set even though hintsp is NULL or
+ * ai_socktype is 0
+ * AI_CANNONNAME does not support.
+ */
+static int ga_unix(const char* path, const struct addrinfo* hintsp,
+ struct addrinfo** result)
+{
+ struct addrinfo hints;
+ struct addrinfo* aip;
+ struct sockaddr_un* unp;
+ memset(&hints, 0, sizeof(hints));
+
+
+ if(hintsp == NULL){
+ hints.ai_family = AF_UNIX;
+ hints.ai_socktype = SOCK_STREAM;
+ }
+ else {
+ memcpy(&hints, hintsp, sizeof(hints));
+ }
+ if(hints.ai_socktype == 0){
+ hints.ai_socktype = SOCK_STREAM;
+ }
+
+ if(!(hints.ai_family == AF_UNIX)){
+ printf("hints.ai_family is invalied ga_unix()\n");
+ return EAI_ADDRFAMILY;
+ }
+
+
+ aip = calloc(1, sizeof(struct addrinfo));
+ if(aip == NULL){
+ return EAI_MEMORY;
+ }
+
+ aip->ai_family = AF_UNIX;
+ aip->ai_socktype = hints.ai_socktype;
+ aip->ai_protocol = hints.ai_protocol;
+ aip->ai_next = NULL;
+ aip->ai_canonname = NULL;
+ *result = aip;
+
+ unp = calloc(1, sizeof(struct sockaddr_un));
+ if(aip == NULL){
+ return EAI_MEMORY;
+ }
+
+ unp->sun_family = AF_UNIX;
+ aip->ai_addr = (struct sockaddr*) unp;
+ aip->ai_addrlen = sizeof(struct sockaddr_un);
+
+ if(strlen(path) >= sizeof(unp->sun_path)){
+ return EAI_SERVICE;
+ }
+ strcpy(unp->sun_path, path);
+
+#if SALEN
+ unp->sun_len = sizeof(struct sockaddr_un);
+#endif /* SALEN */
+
+ if(hints.ai_flags & AI_PASSIVE){
+ unlink(unp->sun_path);
+ }
+
+ return 0;
+}
+#endif /* HAVE_UNIX_SOCKETS */
+
+
+
+
+
+/**
+ * SockAddr_ntop - set IP address string from SockAddr
+ *
+ * parameters... sa : SockAddr union
+ * dst : buffer for address string
+ * cnt : sizeof dst
+ * v4conv: non-zero: if address is IPv4 mapped IPv6 address then
+ * convert to IPv4 address.
+ * returns... pointer to dst
+ * if sa.sa_family is not AF_INET or AF_INET6 dst is set as empy string.
+ */
+char* SockAddr_ntop(const SockAddr* sa, char* dst, size_t cnt, int v4conv)
+{
+ switch(sa->sa.sa_family){
+ case AF_INET:
+ inet_ntop(AF_INET, &sa->in.sin_addr, dst, cnt);
+ break;
+ case AF_INET6:
+ inet_ntop(AF_INET6, &sa->in6.sin6_addr, dst, cnt);
+ if(v4conv && IN6_IS_ADDR_V4MAPPED(&sa->in6.sin6_addr) ){
+ strcpy(dst, dst + 7);
+ }
+ break;
+ default:
+ dst[0] = '\0';
+ break;
+ }
+ return dst;
+}
+
+int SockAddr_pton(SockAddr* sa, const char* src, size_t cnt)
+{
+ int i;
+ int family = AF_INET;
+ for(i = 0; i < cnt; i++){
+ if(src[i] == ':'){
+ family = AF_INET6;
+ break;
+ }
+ }
+
+ sa->sa.sa_family = family;
+ switch(family){
+ case AF_INET:
+ return inet_pton(AF_INET, src, &sa->in.sin_addr);
+ case AF_INET6:
+ return inet_pton(AF_INET6, src, &sa->in6.sin6_addr);
+ break;
+ default:
+ return -1;
+ }
+}
+
+
+
+
+/**
+ * isAF_INETx - check to see if sa is AF_INET or AF_INET6
+ *
+ * parameters... sa : SockAddr union
+ * returns...
+ * if sa->sa.sa_famil is AF_INET or AF_INET6 then
+ * return 1
+ * else
+ * return 0
+ */
+int isAF_INETx(const SockAddr* sa)
+{
+ if(sa->sa.sa_family == AF_INET ||
+ sa->sa.sa_family == AF_INET6
+ ){
+ return 1;
+ }
+ else {
+ return 0;
+ }
+}
+
+int isAF_INETx2(int family)
+{
+ if(family == AF_INET ||
+ family == AF_INET6
+ ){
+ return 1;
+ }
+ else {
+ return 0;
+ }
+}
+
+
+int rangeSockAddr(const SockAddr* addr, const SockAddr* netaddr, const SockAddr* netmask)
+{
+ if(addr->sa.sa_family == AF_INET){
+ return rangeSockAddrAF_INET(addr, netaddr, netmask);
+ }
+ else if(addr->sa.sa_family == AF_INET6){
+ return rangeSockAddrAF_INET6(addr, netaddr, netmask);
+ }
+ else {
+ return 0;
+ }
+}
+
+int rangeSockAddrAF_INET(const SockAddr* addr, const SockAddr* netaddr,
+ const SockAddr* netmask)
+{
+ if(addr->sa.sa_family != AF_INET ||
+ netaddr->sa.sa_family != AF_INET ||
+ netmask->sa.sa_family != AF_INET ){
+ return 0;
+ }
+ if( ((addr->in.sin_addr.s_addr ^ netaddr->in.sin_addr.s_addr ) &
+ netmask->in.sin_addr.s_addr) == 0){
+ return 1;
+ }
+ else {
+ return 0;
+ }
+}
+
+int rangeSockAddrAF_INET6(const SockAddr* addr, const SockAddr* netaddr,
+ const SockAddr* netmask)
+{
+ int i;
+
+ if(IN6_IS_ADDR_V4MAPPED(&addr->in6.sin6_addr) ){
+ SockAddr addr4;
+ convSockAddr6to4(addr, &addr4);
+ if(rangeSockAddrAF_INET(&addr4, netaddr, netmask)){
+ return 1;
+ }
+ }
+
+ if(netaddr->sa.sa_family != AF_INET6 ||
+ netmask->sa.sa_family != AF_INET6 ){
+ return 0;
+ }
+
+ for( i = 0; i < 16; i++){
+ if( ((addr->in6.sin6_addr.s6_addr[i] ^ netaddr->in6.sin6_addr.s6_addr[i] ) &
+ netmask->in6.sin6_addr.s6_addr[i] ) != 0){
+ return 0;
+ }
+ }
+
+ return 1;
+}
+
+void convSockAddr6to4(const SockAddr* src, SockAddr* dst)
+{
+ char addr_str[INET6_ADDRSTRLEN];
+
+ dst->in.sin_family = AF_INET;
+ dst->in.sin_port = src->in6.sin6_port;
+
+ dst->in.sin_addr.s_addr = src->in6.sin6_addr.s6_addr32[3];
+ SockAddr_ntop(src, addr_str, INET6_ADDRSTRLEN, 0);
+}
+
+
diff --git a/src/include/libpq/v6util.h b/src/include/libpq/v6util.h
new file mode 100644
index 0000000000000000000000000000000000000000..6e325d17c0753672f690db9e38144c4368024c55
--- /dev/null
+++ b/src/include/libpq/v6util.h
@@ -0,0 +1,17 @@
+#ifndef V6UTIL_H
+#define V6UTIL_H
+void freeaddrinfo2(int hint_ai_family, struct addrinfo *ai);
+int getaddrinfo2(const char* hostname, const char* servname,
+ const struct addrinfo* hintp, struct addrinfo **result);
+char* SockAddr_ntop(const SockAddr* sa, char* dst, size_t cnt, int v4conv);
+int SockAddr_pton(SockAddr* sa, const char* src, size_t cnt);
+int isAF_INETx(const SockAddr* sa);
+int isAF_INETx2(int family);
+int rangeSockAddr(const SockAddr* addr, const SockAddr* netaddr, const SockAddr* netmask);
+int rangeSockAddrAF_INET(const SockAddr* addr, const SockAddr* netaddr,
+ const SockAddr* netmask);
+int rangeSockAddrAF_INET6(const SockAddr* addr, const SockAddr* netaddr,
+ const SockAddr* netmask);
+void convSockAddr6to4(const SockAddr* src, SockAddr* dst);
+
+#endif /* V6UTIL_H */