- isc__netievent_storage_t was to small to contain
isc__netievent__socket_streaminfo_t on Windows
- handle isc_uv_export and isc_uv_import errors properly
- rewrite isc_uv_export and isc_uv_import on Windows
If a connection was closed early (right after accept()) an assertion
that assumed that the connection was still alive could be triggered
in accept_connection. Handle those errors properly and not with
assertions, free all the resources afterwards.
- the socket stat counters have been moved from socket.h to stats.h.
- isc_nm_t now attaches to the same stats counter group as
isc_socketmgr_t, so that both managers can increment the same
set of statistics
- isc__nmsocket_init() now takes an interface as a paramter so that
the address family can be determined when initializing the socket.
- based on the address family and socket type, a group of statistics
counters will be associated with the socket - for example, UDP4Active
with IPv4 UDP sockets and TCP6Active with IPv6 TCP sockets. note
that no counters are currently associated with TCPDNS sockets; those
stats will be handled by the underlying TCP socket.
- the counters are not actually used by netmgr sockets yet; counter
increment and decrement calls will be added in a later commit.
- use UV_{TC,UD}P_IPV6ONLY for IPv6 sockets, keeping the pre-netmgr
behaviour.
- add a new listening_error bool flag which is set if the child
listener fails to start listening. This fixes a bug where named would
hang if, e.g., we failed to bind to a TCP socket.
For multithreaded TCP listening we need to pass a bound socket to all
listening threads. Instead of using uv_pipe handle passing method which
is quite complex (lots of callbacks, each of them with its own error
handling) we now use isc_uv_export() to export the socket, pass it as a
member of the isc__netievent_tcpchildlisten_t structure, and then
isc_uv_import() it in the child thread, simplifying the process
significantly.
- make tcp listening IPC pipe name saner
- put the pipe in /tmp on unices
- add pid to the pipe name to avoid conflicts between processes
- fsync directory in which the pipe resides to make sure that the
child threads will see it and be able to open it
even when worker is paused (e.g. interface reconfiguration). This is
needed to prevent deadlocks when reconfiguring interfaces - as network
manager is paused then, but we still need to stop/start listening.
- Proper handling of TCP listen errors in netmgr - bind to the socket first,
then return the error code.
When listening for TCP connections we create a socket, bind it
and then pass it over IPC to all threads - which then listen on
in and accept connections. This sounds broken, but it's the
official way of dealing with multithreaded TCP listeners in libuv,
and works on all platforms supported by libuv.
- restore support for tcp-initial-timeout, tcp-idle-timeout,
tcp-keepalive-timeout and tcp-advertised-timeout configuration
options, which were ineffective previously.
- add timeout support for TCP and TCPDNS connections to protect against
slowloris style attacks. currently, all timeouts are hard-coded.
- rework and simplify the TCPDNS state machine.
when the TCPDNS_CLIENTS_PER_CONN limit has been exceeded for a TCP
DNS connection, switch to sequential mode to ensure that memory cannot
be exhausted by too many simultaneous queries.
This is a replacement for the existing isc_socket and isc_socketmgr
implementation. It uses libuv for asynchronous network communication;
"networker" objects will be distributed across worker threads reading
incoming packets and sending them for processing.
UDP listener sockets automatically create an array of "child" sockets
so each worker can listen separately.
TCP sockets are shared amongst worker threads.
A TCPDNS socket is a wrapper around a TCP socket, which handles the
the two-byte length field at the beginning of DNS messages over TCP.
(Other wrapper socket types can be implemented in the future to handle
DNS over TLS, DNS over HTTPS, etc.)
