--- /dev/null
+#include <ccan/net/net.h>
+#include <ccan/noerr/noerr.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <poll.h>
+#include <netdb.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <stdbool.h>
+
+struct addrinfo *net_client_lookup(const char *hostname,
+ const char *service,
+ int family,
+ int socktype)
+{
+ struct addrinfo hints;
+ struct addrinfo *res;
+
+ memset(&hints, 0, sizeof(hints));
+ hints.ai_family = family;
+ hints.ai_socktype = socktype;
+ hints.ai_flags = 0;
+ hints.ai_protocol = 0;
+
+ if (getaddrinfo(hostname, service, &hints, &res) != 0)
+ return NULL;
+
+ return res;
+}
+
+static bool set_nonblock(int fd, bool nonblock)
+{
+ long flags;
+
+ flags = fcntl(fd, F_GETFL);
+ if (flags == -1)
+ return false;
+
+ if (nonblock)
+ flags |= O_NONBLOCK;
+ else
+ flags &= ~(long)O_NONBLOCK;
+
+ return (fcntl(fd, F_SETFL, flags) == 0);
+}
+
+/* We only handle IPv4 and IPv6 */
+#define MAX_PROTOS 2
+
+static void remove_fd(struct pollfd pfd[],
+ const struct addrinfo *addr[],
+ socklen_t slen[],
+ unsigned int *num,
+ unsigned int i)
+{
+ memmove(pfd + i, pfd + i + 1, (*num - i - 1) * sizeof(pfd[0]));
+ memmove(addr + i, addr + i + 1, (*num - i - 1) * sizeof(addr[0]));
+ memmove(slen + i, slen + i + 1, (*num - i - 1) * sizeof(slen[0]));
+ (*num)--;
+}
+
+int net_connect(const struct addrinfo *addrinfo)
+{
+ int sockfd = -1;
+ unsigned int i, num;
+ const struct addrinfo *ipv4 = NULL, *ipv6 = NULL;
+ const struct addrinfo *addr[MAX_PROTOS];
+ socklen_t slen[MAX_PROTOS];
+ struct pollfd pfd[MAX_PROTOS];
+
+ for (; addrinfo; addrinfo = addrinfo->ai_next) {
+ switch (addrinfo->ai_family) {
+ case AF_INET:
+ if (!ipv4)
+ ipv4 = addrinfo;
+ break;
+ case AF_INET6:
+ if (!ipv6)
+ ipv6 = addrinfo;
+ break;
+ }
+ }
+
+ num = 0;
+ /* We give IPv6 a slight edge by connecting it first. */
+ if (ipv6) {
+ addr[num] = ipv6;
+ slen[num] = sizeof(struct sockaddr_in6);
+ pfd[num].fd = socket(AF_INET6, ipv6->ai_socktype,
+ ipv6->ai_protocol);
+ if (pfd[num].fd != -1)
+ num++;
+ }
+ if (ipv4) {
+ addr[num] = ipv4;
+ slen[num] = sizeof(struct sockaddr_in);
+ pfd[num].fd = socket(AF_INET, ipv4->ai_socktype,
+ ipv4->ai_protocol);
+ if (pfd[num].fd != -1)
+ num++;
+ }
+
+ for (i = 0; i < num; i++) {
+ if (!set_nonblock(pfd[i].fd, true)) {
+ remove_fd(pfd, addr, slen, &num, i--);
+ continue;
+ }
+ /* Connect *can* be instant. */
+ if (connect(pfd[i].fd, addr[i]->ai_addr, slen[i]) == 0)
+ goto got_one;
+ if (errno != EINPROGRESS) {
+ /* Remove dead one. */
+ remove_fd(pfd, addr, slen, &num, i--);
+ }
+ pfd[i].events = POLLOUT;
+ }
+
+ while (num && poll(pfd, num, -1) != -1) {
+ for (i = 0; i < num; i++) {
+ int err;
+ socklen_t errlen = sizeof(err);
+ if (!pfd[i].revents)
+ continue;
+ if (getsockopt(pfd[i].fd, SOL_SOCKET, SO_ERROR, &err,
+ &errlen) != 0)
+ goto out;
+ if (err == 0)
+ goto got_one;
+
+ /* Remove dead one. */
+ errno = err;
+ remove_fd(pfd, addr, slen, &num, i--);
+ }
+ }
+
+got_one:
+ /* We don't want to hand them a non-blocking socket! */
+ if (set_nonblock(pfd[i].fd, false))
+ sockfd = pfd[i].fd;
+
+out:
+ for (i = 0; i < num; i++)
+ if (pfd[i].fd != sockfd)
+ close_noerr(pfd[i].fd);
+ return sockfd;
+}