连接一个 UDP 套接字，但仍然接收来自其他来源的数据报

Question

Is it possible to set the default destination of a UDP socket just like connect does, but without loosing the ability to receive datagrams from other sources?

I'm talking about the native OS socket API (BSD-socket / winsock2) and I'm interested in answers for both linux and windows platforms.

[ EDIT :]
In case this is unclear, here is the problematic part from the connect docs :

If the socket sockfd is of type SOCK_DGRAM then addr is the address to which datagrams are sent by default, and the only address from which datagrams are received.

Answer 1

Is it possible to set the default destination of a UDP socket just like connect does, but without loosing the ability to receive packages from other sources?

As far as I can tell, it is not -- connect() on a UDP socket both sets a default-send-destination and installs a filter so that incoming UDP packets from all other destinations than the specified address/port are dropped.

My solution to the problem was to just call sendto() and recvfrom() instead (if you have a UDPSocket class or similar in your codebase, you can cache the default-send address as a private member variable in that class, so that the rest of your codebase can just call a Send() method, and leave it to that method to handle the sendto() arguments)