Quelle est la différence entre SO_REUSEADDR et SO_REUSEPORT ?
Bienvenue dans le merveilleux monde de la portabilité… ou plutôt de son absence. Before we start analyzing these two options in detail and take a deeper look how different operating systems handle them, it should be noted that the BSD socket implementation is the mother of all socket implementations. Basically all other systems copied the BSD socket implementation at some point in time (or at least its interfaces) and then started evolving it on their own. Of course the BSD socket implementation was evolved as well at the same time and thus systems that copied it later got features that were lacking in systems that copied it earlier. Understanding the BSD socket implementation is the key to understanding all other socket implementations, so you should read about it even if you don’t care to ever write code for a BSD system.
There are a couple of basics you should know before we look at these two options. A TCP/UDP connection is identified by a tuple of five values:
{<protocol>, <src addr>, <src port>, <dest addr>, <dest port>}
Any unique combination of these values identifies a connection. As a result, no two connections can have the same five values, otherwise the system would not be able to distinguish these connections any longer.
The protocol of a socket is set when a socket is created with the socket() function. The source address and port are set with the bind() function. The destination address and port are set with the connect() function. Since UDP is a connectionless protocol, UDP sockets can be used without connecting them. Yet it is allowed to connect them and in some cases very advantageous for your code and general application design. In connectionless mode, UDP sockets that were not explicitly bound when data is sent over them for the first time are usually automatically bound by the system, as an unbound UDP socket cannot receive any (reply) data. Same is true for an unbound TCP socket, it is automatically bound before it will be connected.
If
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