+ if (ret >= 0)
+ ret = makesock_addrinfo(l4type, passive, ai, fo);
+ if (ai)
+ freeaddrinfo(ai);
+ if (ret < 0) {
+ PARA_ERROR_LOG("can not create %s socket %s#%d.\n",
+ layer4_name(l4type), host? host : (passive?
+ "[loopback]" : "[localhost]"), port_number);
+ }
+ return ret;
+}
+
+/**
+ * Create a passive / listening socket.
+ *
+ * \param l4type The transport-layer type (\p IPPROTO_xxx).
+ * \param port The decimal port number to listen on.
+ * \param fo Flowopts (if any) to set before starting to listen.
+ *
+ * \return Positive integer (socket descriptor) on success, negative value
+ * otherwise.
+ *
+ * \sa makesock(), ip(7), ipv6(7), bind(2), listen(2).
+ */
+int para_listen(unsigned l4type, uint16_t port, struct flowopts *fo)
+{
+ int ret, fd = makesock(l4type, 1, NULL, port, fo);
+
+ if (fd > 0) {
+ ret = listen(fd, BACKLOG);
+ if (ret < 0) {
+ ret = errno;
+ close(fd);
+ return -ERRNO_TO_PARA_ERROR(ret);
+ }
+ PARA_INFO_LOG("listening on %s port %u, fd %d\n",
+ layer4_name(l4type), port, fd);
+ }
+ return fd;
+}
+
+/**
+ * Determine IPv4/v6 socket address length.
+ * \param sa Container of IPv4 or IPv6 address.
+ * \return Address-family dependent address length.
+ */
+static socklen_t salen(const struct sockaddr *sa)
+{
+ assert(sa->sa_family == AF_INET || sa->sa_family == AF_INET6);
+
+ return sa->sa_family == AF_INET6
+ ? sizeof(struct sockaddr_in6)
+ : sizeof(struct sockaddr_in);
+}
+
+/** True if @ss holds a v6-mapped-v4 address (RFC 4291, 2.5.5.2) */
+static bool SS_IS_ADDR_V4MAPPED(const struct sockaddr_storage *ss)
+{
+ const struct sockaddr_in6 *ia6 = (const struct sockaddr_in6 *)ss;
+
+ return ss->ss_family == AF_INET6 && IN6_IS_ADDR_V4MAPPED(&ia6->sin6_addr);
+}
+
+/**
+ * Process IPv4/v6 address, turn v6-mapped-v4 address into normal IPv4 address.
+ * \param ss Container of IPv4/6 address.
+ * \return Pointer to normalized address (may be static storage).
+ *
+ * \sa RFC 3493
+ */
+static const struct sockaddr *
+normalize_ip_address(const struct sockaddr_storage *ss)
+{
+ assert(ss->ss_family == AF_INET || ss->ss_family == AF_INET6);
+
+ if (SS_IS_ADDR_V4MAPPED(ss)) {
+ const struct sockaddr_in6 *ia6 = (const struct sockaddr_in6 *)ss;
+ static struct sockaddr_in ia;
+
+ ia.sin_family = AF_INET;
+ ia.sin_port = ia6->sin6_port;
+ memcpy(&ia.sin_addr.s_addr, &(ia6->sin6_addr.s6_addr[12]), 4);
+ return (const struct sockaddr *)&ia;
+ }
+ return (const struct sockaddr *)ss;