+
+/**
+ * net_connect_async - initiate connect to a server
+ * @addrinfo: linked list struct addrinfo (usually from net_client_lookup).
+ * @pfds: array of two struct pollfd.
+ *
+ * This begins connecting to a server described by @addrinfo,
+ * and places the one or two file descriptors into pfds[0] and pfds[1].
+ * It returns a valid file descriptor if connect() returned immediately.
+ *
+ * Otherwise it returns -1 and sets errno, most likely EINPROGRESS.
+ * In this case, poll() on pfds and call net_connect_complete().
+ *
+ * Example:
+ * struct pollfd pfds[2];
+ * ...
+ * fd = net_connect_async(addr, pfds);
+ * if (fd < 0 && errno != EINPROGRESS)
+ * err(1, "Failed to connect to ccan.ozlabs.org");
+ */
+int net_connect_async(const struct addrinfo *addrinfo, struct pollfd *pfds);
+
+/**
+ * net_connect_complete - complete net_connect_async call.
+ * @pfds: array of two struct pollfd handed to net_connect_async.
+ *
+ * When poll() reports some activity, this determines whether a connection
+ * has completed. If so, it cleans up and returns the connected fd.
+ * Otherwise, it returns -1, and sets errno (usually EINPROGRESS).
+ *
+ * Example:
+ * // After net_connect_async.
+ * while (fd < 0 && errno == EINPROGRESS) {
+ * // Wait for activity...
+ * poll(pfds, 2, -1);
+ * fd = net_connect_complete(pfds);
+ * }
+ * if (fd < 0)
+ * err(1, "connecting");
+ * printf("Connected on fd %i!\n", fd);
+ */
+int net_connect_complete(struct pollfd *pfds);
+
+/**
+ * net_connect_abort - abort a net_connect_async call.
+ * @pfds: array of two struct pollfd handed to net_connect_async.
+ *
+ * Closes the file descriptors.
+ *
+ * Example:
+ * // After net_connect_async.
+ * if (poll(pfds, 2, 1000) == 0) { // Timeout.
+ * net_connect_abort(pfds);
+ * fd = -1;
+ * } else {
+ * fd = net_connect_complete(pfds);
+ * if (fd < 0)
+ * err(1, "connecting");
+ * }
+ */
+void net_connect_abort(struct pollfd *pfds);
+
+/**
+ * net_server_lookup - look up a service name to bind to.
+ * @service: the service to look up
+ * @family: Usually AF_UNSPEC, otherwise AF_INET or AF_INET6.
+ * @socktype: SOCK_DGRAM or SOCK_STREAM.
+ *
+ * This will do a synchronous lookup of a given name, returning a linked list
+ * of results, or NULL on error. You should use freeaddrinfo() to free it.
+ *
+ * Example:
+ * #include <stdio.h>
+ * #include <err.h>
+ * ...
+ * struct addrinfo *addr;
+ *
+ * // Get address(es) to bind for our service.
+ * addr = net_server_lookup("8888", AF_UNSPEC, SOCK_STREAM);
+ * if (!addr)
+ * errx(1, "Failed to look up 8888 to bind to");
+ */
+struct addrinfo *net_server_lookup(const char *service,
+ int family,
+ int socktype);
+
+/**
+ * net_bind - create listening socket(s)
+ * @addrinfo: the address(es) to bind to.
+ * @fds: array of two fds.
+ *
+ * This will create one (or if necessary) two sockets, mark them
+ * SO_REUSEADDR, bind them to the given address(es), and make them
+ * listen() (if the socket type is SOCK_STREAM or SOCK_SEQPACKET).
+ *
+ * Returns -1 (and sets errno) on error, or 1 or 2 depending on how many
+ * @fds are valid.
+ *
+ * Example:
+ * int fds[2], i, num_fds;
+ *
+ * num_fds = net_bind(addr, fds);
+ * if (num_fds < 0)
+ * err(1, "Failed to listen on port 8888");
+ *
+ * for (i = 0; i < num_fds; i++)
+ * printf(" Got fd %u/%u: %i\n", i, num_fds, fds[i]);
+ */
+int net_bind(const struct addrinfo *addrinfo, int fds[2]);