Function tap_nl_recv

dpdk/drivers/net/tap/tap_netlink.c:236–280

* Receive a message from the kernel on the netlink socket, following an * tap_nl_send(). * * @param[in] nlsk_fd * The netlink socket file descriptor used for communication. * @param[in] cb * The callback function to call for each netlink message received. * @param[in, out] arg * Custom arguments for the callback. * * @return * 0 on success, -1 otherwise with errno set. */

 *   0 on success, -1 otherwise with errno set.
 */
int
tap_nl_recv(int nlsk_fd, int (*cb)(struct nlmsghdr *, void *arg), void *arg)
{
	char buf[BUF_SIZE];
	int multipart = 0;
	int ret = 0;

	do {
		struct nlmsghdr *nh;
		int recv_bytes;

retry:
		recv_bytes = recv(nlsk_fd, buf, sizeof(buf), 0);
		if (recv_bytes < 0) {
			if (errno == EINTR)
				goto retry;
			return -1;
		}

		for (nh = (struct nlmsghdr *)buf;
		     NLMSG_OK(nh, (unsigned int)recv_bytes);
		     nh = NLMSG_NEXT(nh, recv_bytes)) {
			if (nh->nlmsg_type == NLMSG_ERROR) {
				struct nlmsgerr *err_data = NLMSG_DATA(nh);

				tap_nl_dump_ext_ack(nh, err_data);
				if (err_data->error < 0) {
					errno = -err_data->error;
					return -1;
				}
				/* Ack message. */
				return 0;
			}
			/* Multi-part msgs and their trailing DONE message. */
			if (nh->nlmsg_flags & NLM_F_MULTI) {
				if (nh->nlmsg_type == NLMSG_DONE)
					return 0;
				multipart = 1;
			}
			if (cb)
				ret = cb(nh, arg);
		}
	} while (multipart);
	return ret;
}

/**
 * Append a netlink attribute to a message.