Question

I have a program that consists of a master server and distributed slave servers. The slave servers send status updates to the server, and if the server hasn’t heard from a specific slave in a fixed period, it marks the slave as down. This is happening consistently.

From inspecting logs, I have found that the slave is only able to send one status update to the server, and then is never able to send another update, always failing on the call to connect() “Cannot assign requested address (99).

Oddly enough, the slave is able to send several other updates to the server, and all of the connections are happening on the same port. It seems that the most common cause of this failure is that connections are left open, but I’m having trouble finding anything left open. Are there other possible explanations?

To clarify, here’s how I’m connecting:

struct sockaddr *sa; // parameter
size_t           sa_size; //parameter
int              i = 1;
int              stream;

stream = socket(AF_INET,SOCK_STREAM,0);
setsockopt(stream,SOL_SOCKET,SO_REUSEADDR,&i,sizeof(i));
bindresvport(stream,NULL);
connect(stream,sa,sa_size);

This code is in a function to obtain a connection to another server, and a failure on any of those 4 calls causes the function to fail.

Answer 1

Maybe SO_REUSEADDR helps here?
http://www.unixguide.net/network/socketfaq/4.5.shtml