On Thu, 28 Sep 2017 21:33:45 +0800
Hangbin Liu <[email protected]> wrote:
>
> +static int __rtnl_recvmsg(int fd, struct msghdr *msg, int flags)
> +{
> + int len;
> +
> + do {
> + len = recvmsg(fd, msg, flags);
> + } while (len < 0 && (errno == EINTR || errno == EAGAIN));
> +
> + if (len < 0) {
> + fprintf(stderr, "netlink receive error %s (%d)\n",
> + strerror(errno), errno);
> + return -errno;
> + }
> +
> + if (len == 0) {
> + fprintf(stderr, "EOF on netlink\n");
> + return -ENODATA;
> + }
> +
> + return len;
> +}
> +
> +static int rtnl_recvmsg(int fd, struct msghdr *msg, char **answer)
> +{
> + struct iovec *iov = msg->msg_iov;
> + char *buf;
> + int len;
> +
> + iov->iov_base = NULL;
> + iov->iov_len = 0;
> +
> + len = __rtnl_recvmsg(fd, msg, MSG_PEEK | MSG_TRUNC);
> + if (len < 0)
> + return len;
> +
> + buf = malloc(len);
> + if (!buf) {
> + fprintf(stderr, "malloc error: not enough buffer\n");
> + return -ENOMEM;
> + }
> +
> + iov->iov_base = buf;
> + iov->iov_len = len;
> +
> + len = __rtnl_recvmsg(fd, msg, 0);
> + if (len < 0) {
> + free(buf);
> + return len;
> + }
> +
> + if (answer)
> + *answer = buf;
> + else
> + free(buf);
> +
> + return len;
> +}
Doubling the number of system calls per message is not going to make
users with 5,000,000 routes or 1000 vlans, or 10,000 tunnels happy.
Please rethink this.
