Prabhu S wrote:
On 2/20/08, *David Schwartz* <[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>> wrote:> But, the application code tries to clear out/shutdown existing > SSL session with orderly bi-directional alerts. Once shutdown it > creates a new SSL object 'ssl' [ssl = SSL_new (ctx)] > for the next session in persistent connection.. This is nearly impossible to do. It's possible that you did it correctly, but very unlikely. The basic problem is this -- when you call 'read' to get the last message of the first session, how do you make sure you also don't get all or part of the first message of the second session?I do not think it is very difficult. The application initiates SSL sessions sequentially in a established socket connection.One cycle of SSL_connect - DataExchange-SSL_shutdown is followed by another cycle of SSL_connect - DataExchange-SSL_shutdown. As such there shouldn't be issue of session mix up.At least that is what is observed with say 400-500 clients connecting to server simultaneously.
Isn't it possible you got lucky under just the 'right' conditions? Can you guarantee it will always work?
> When the app simulates limited clients , say, 100, each client makes > hundreds of unique SSL sessions successfully in persistent connection. > It is under stress of ~800 clients , that I run into issues. > Also, the bi-directional alerts do not happen always under > high stress..could this be the reason? a possible session data mix up? Either your code properly separates the sessions or it doesn't. My bet is that it doesn't because this is very hard to do right.Yes. I believe so..I am able to establish hundreds of cycles of new sessions in persistent connection. The trouble is under high stress sessions fail as indicated by ethereal trace.Sometimes server complains of Bad_MAC error on receiving Finished message from client.Why do you do things this way? It's just plain wrong. Either layer on top of SSL or don't, but splitting the difference and "sort of" layering between SSL and TCP is just plain crazy.Multiple sessions are tried in a single TCP connect to reduce the overhead of TCP handshake and termination if the client wishes to do multiple 'new' SSL connects to server.
Have you quantified this overhead? What percentage of session establishment is TCP handshake overhead?
Thanks, Prabhu. S
Good luck! -jb -- I used to think I was indecisive, but now I'm not so sure. ______________________________________________________________________ OpenSSL Project http://www.openssl.org User Support Mailing List openssl-users@openssl.org Automated List Manager [EMAIL PROTECTED]
