helloword sever demo support IPv6.

F-Stack's kni can work on DPDK 18.11 LTS now.

F-Stack's kni can work on DPDK 18.11 LTS now.

remove unnecessary one byte from html page

remove unnecessary one byte from html page

Example: fix listen queue overflow.

According to the FreeBSD Manual Page:
- When kevent() returns and if `flags` is EVFILT_READ, sockets which have previously been passed to listen() return when the

Example: fix listen queue overflow.

According to the FreeBSD Manual Page:
- When kevent() returns and if `flags` is EVFILT_READ, sockets which have previously been passed to listen() return when there is an incoming connection pending. `data` contains the size of the listen backlog.

So if an EVFILT_READ event reaches and it is the listen socket, we must accept `event->data` times. And for `ff_epoll` interface, we should continue to accept until it fails.

In the previous version, we only accept once when event reaches, it will cause listen queue overflow.

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Example: fix listen queue overflow.

According to the FreeBSD Manual Page:
- When kevent() returns and if `flags` is EVFILT_READ, sockets which have previously been passed to listen() return when the

Example: fix listen queue overflow.

According to the FreeBSD Manual Page:
- When kevent() returns and if `flags` is EVFILT_READ, sockets which have previously been passed to listen() return when there is an incoming connection pending. `data` contains the size of the listen backlog.

So if an EVFILT_READ event reaches and it is the listen socket, we must accept `event->data` times. And for `ff_epoll` interface, we should continue to accept until it fails.

In the previous version, we only accept once when event reaches, it will cause listen queue overflow.

show more ...

Example: keep run when accept failed.

Example: keep run when accept failed.

Example: exit when ff_api failed

Fix `ff_fdused_range` not work.

Simplify startup arguments and add ff_fdisused.

Changes:
1.Simplify f-stack startup arguments:"--conf, --proc-type, --proc-id".
2.add a function `ff_fdisused` to check if fd is used in f-stack.

example: remove printf.

init