+ if (local)
+ freeaddrinfo(local);
+ if (remote)
+ freeaddrinfo(remote);
+
+ if (src == NULL && dst == NULL) {
+ PARA_ERROR_LOG("can not create %s socket %s#%s.\n",
+ layer4_name(l4type), host? host : (passive?
+ "[loopback]" : "[localhost]"), port);
+ return -ERRNO_TO_PARA_ERROR(errno);
+ }
+ return sockfd;
+}
+
+/**
+ * Create a passive / listening socket.
+ *
+ * \param l3type The network-layer type (\p AF_xxx).
+ * \param l4type The transport-layer type (\p IPPROTO_xxx).
+ * \param port The decimal port number to listen on.
+ *
+ * \return Positive integer (socket descriptor) on success, negative value
+ * otherwise.
+ *
+ * \sa makesock(), ip(7), ipv6(7), bind(2), listen(2).
+ */
+int para_listen(unsigned l3type, unsigned l4type, unsigned short port)
+{
+ int ret, fd = makesock(l3type, l4type, 1, NULL, port);
+
+ if (fd > 0) {
+ ret = listen(fd, BACKLOG);
+ if (ret < 0) {
+ close(fd);
+ return -ERRNO_TO_PARA_ERROR(errno);
+ }
+ PARA_INFO_LOG("listening on %s port %u, fd %d\n",
+ layer4_name(l4type), port, fd);
+ }
+ return fd;
+}
+
+/**
+ * Print numeric host and port number (beware - uses static char).
+ *
+ * \param sa The IPv4/IPv6 socket address to use.
+ * \param len The length of \p sa.
+ *
+ * \sa getnameinfo(3).
+ */
+static char *host_and_port(struct sockaddr *sa, socklen_t len)
+{
+ static char output[NI_MAXHOST + NI_MAXSERV + 2];
+ char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];
+ int ret;
+
+ ret = getnameinfo(sa, len, hbuf, sizeof(hbuf), sbuf, sizeof(sbuf),
+ NI_NUMERICHOST | NI_NUMERICSERV);
+ if (ret) {
+ PARA_WARNING_LOG("hostname lookup error (%s).\n",
+ gai_strerror(ret));
+ sprintf(output, "(unknown)");
+ } else
+ sprintf(output, "%s#%s", hbuf, sbuf);
+ return output;
+}
+
+/**
+ * Look up the local or remote side of a connected socket structure.
+ *
+ * \param fd The socket descriptor of the connected socket.
+ * \param getname Either \p getsockname() for local, or \p getpeername() for
+ * remote side.
+ *
+ * \return A static character string identifying hostname and port of the
+ * chosen side.
+ *
+ * \sa getsockname(2), getpeername(2).
+ */
+static char *__get_sock_name(int fd, int (*getname)(int, struct sockaddr*,
+ socklen_t *))
+{
+ struct sockaddr_storage ss;
+ socklen_t sslen = sizeof(ss);
+
+ if (getname(fd, (struct sockaddr *)&ss, &sslen) < 0) {
+ static char *dont_know = "(don't know)";
+ PARA_ERROR_LOG("can not determine address from fd %d: %s\n",
+ fd, strerror(errno));
+ return dont_know;
+ }
+ return host_and_port((struct sockaddr *)&ss, sslen);
+}
+
+char *local_name(int sockfd)
+{
+ return __get_sock_name(sockfd, getsockname);
+}
+
+char *remote_name(int sockfd)
+{
+ return __get_sock_name(sockfd, getpeername);
+}
+
+/**
+ * Extract IPv4 or IPv6-mapped-IPv4 address from sockaddr_storage.
+ * \param ss Container of IPv4/6 address
+ * \return Extracted IPv4 address (different from 0) or 0 if unsuccessful.
+ *
+ * \sa RFC 3493
+ */
+struct in_addr extract_v4_addr(const struct sockaddr_storage *ss)
+{
+ struct in_addr ia = {.s_addr = 0};
+
+ if (ss->ss_family == AF_INET)
+ ia.s_addr = ((struct sockaddr_in *)ss)->sin_addr.s_addr;
+ if (ss->ss_family == AF_INET6) {
+ const struct in6_addr v6_addr = ((struct sockaddr_in6 *)ss)->sin6_addr;
+
+ if (IN6_IS_ADDR_V4MAPPED(&v6_addr))
+ memcpy(&ia.s_addr, &(v6_addr.s6_addr[12]), 4);
+ }
+ return ia;