http: implement new evhttp_connection_get_addr() api.

Basically tcp final handshake looks like this:
    (C - client, S - server)
    ACK[C] - FIN/ACK[S] - FIN/ACK[S] - ACK [C]

However there are servers, that didn't close connection like this,
while it is still _considered_ as valid, and using libevent http layer
we can do requests to such servers.

Modified handshake:
    (C - client, S - server)
    ACK[C] - RST/ACK[S] - RST/ACK[S]

And in this case we can't extract IP address from socket, because it is
already closed, and getpeername() will return: "transport endpoint is not connected".
So we need to store address that we are connecting to, after we know it,
and that is what this patch do.

I have reproduced it, however it have some extra packages.
(I will try to fix it)
https://github.com/azat/nfq-examples/blob/master/nfqnl_rst_fin.c

1 files changed, 7 insertions, 0 deletions

diff --git a/http-internal.h b/http-internal.h
index d25753bb..82dd402a 100644
--- a/http-internal.h
+++ b/http-internal.h
@@ -99,6 +99,13 @@ struct evhttp_connection {
 
 	struct event_base *base;
 	struct evdns_base *dns_base;
+
+	/* Saved conn_addr, to extract IP address from it.
+	 *
+	 * Because some servers may reset/close connection without waiting clients,
+	 * in that case we can't extract IP address even in close_cb.
+	 * So we need to save it, just after we connected to remote server. */
+	struct sockaddr_storage *conn_address;
 };
 
 /* A callback for an http server */