+#ifndef NO_IPV6
+
+static int socksetup(int port, int **socklist_p)
+{
+ int socknum = 0, *socklist = NULL;
+ int maxfd = -1;
+ char pbuf[NI_MAXSERV];
+
+ struct addrinfo hints, *ai0, *ai;
+ int gai;
+
+ sprintf(pbuf, "%d", port);
+ memset(&hints, 0, sizeof(hints));
+ hints.ai_family = AF_UNSPEC;
+ hints.ai_socktype = SOCK_STREAM;
+ hints.ai_protocol = IPPROTO_TCP;
+ hints.ai_flags = AI_PASSIVE;
+
+ gai = getaddrinfo(NULL, pbuf, &hints, &ai0);
+ if (gai)
+ die("getaddrinfo() failed: %s\n", gai_strerror(gai));
+
+ for (ai = ai0; ai; ai = ai->ai_next) {
+ int sockfd;
+ int *newlist;
+
+ sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
+ if (sockfd < 0)
+ continue;
+ if (sockfd >= FD_SETSIZE) {
+ error("too large socket descriptor.");
+ close(sockfd);
+ continue;
+ }
+
+#ifdef IPV6_V6ONLY
+ if (ai->ai_family == AF_INET6) {
+ int on = 1;
+ setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
+ &on, sizeof(on));
+ /* Note: error is not fatal */
+ }
+#endif
+
+ if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
+ close(sockfd);
+ continue; /* not fatal */
+ }
+ if (listen(sockfd, 5) < 0) {
+ close(sockfd);
+ continue; /* not fatal */
+ }
+
+ newlist = realloc(socklist, sizeof(int) * (socknum + 1));
+ if (!newlist)
+ die("memory allocation failed: %s", strerror(errno));
+
+ socklist = newlist;
+ socklist[socknum++] = sockfd;
+
+ if (maxfd < sockfd)
+ maxfd = sockfd;
+ }
+
+ freeaddrinfo(ai0);
+
+ *socklist_p = socklist;
+ return socknum;
+}
+
+#else /* NO_IPV6 */
+
+static int socksetup(int port, int **socklist_p)