I have recently started using SSL with LWP and it works great! I am currently going through the code to get a basic understanding of where (and how) the SSL handshake happens. After enabling debugs in SSL.pm, I figured that connect_SSL() is the relevant function call and the SSL handshake seems to be 'complete' after the following code snippet: 

    for my $dummy (1) {
        #DEBUG( 'calling ssleay::connect' );
        my $rv = Net::SSLeay::connect($ssl);
        $DEBUG>=3 && DEBUG("Net::SSLeay::connect -> $rv" );
        if ( $rv < 0 ) {
            unless ( $self->_set_rw_error( $ssl,$rv )) {
                $self->error("SSL connect attempt failed with unknown 
+error");
                delete ${*$self}{'_SSL_opening'};
                ${*$self}{'_SSL_opened'} = -1;
                $DEBUG>=1 && DEBUG( "fatal SSL error: $SSL_ERROR" );
                return $self->fatal_ssl_error();
            }

            $DEBUG>=2 && DEBUG('ssl handshake in progress' );
            # connect failed because handshake needs to be completed
            # if socket was non-blocking or no timeout was given retur
+n with this error
            return if ! defined($timeout);

            # wait until socket is readable or writable
            my $rv;
            if ( $timeout>0 ) {
                my $vec = '';
                vec($vec,$self->fileno,1) = 1;
                $DEBUG>=2 && DEBUG( "waiting for fd to become ready: $
+SSL_ERROR" );
                $rv =
                    $SSL_ERROR == SSL_WANT_READ ? select( $vec,undef,u
+ndef,$timeout) :
                    $SSL_ERROR == SSL_WANT_WRITE ? select( undef,$vec,
+undef,$timeout) :
                    undef;
            } else {
                $DEBUG>=2 && DEBUG("handshake failed because no more t
+ime" );
                $! = ETIMEDOUT
            }
            if ( ! $rv ) {
                $DEBUG>=2 && DEBUG("handshake failed because socket di
+d not became ready" );
                # failed because of timeout, return
                $! ||= ETIMEDOUT;
                delete ${*$self}{'_SSL_opening'};
                ${*$self}{'_SSL_opened'} = -1;
                $self->blocking(1); # was blocking before
                return
            }

            # socket is ready, try non-blocking connect again after re
+computing timeout
            $DEBUG>=2 && DEBUG("socket ready, retrying connect" );
            my $now = time();
            $timeout -= $now - $start;
            $start = $now;
            redo;

        } elsif ( $rv == 0 ) {
            delete ${*$self}{'_SSL_opening'};
            $DEBUG>=2 && DEBUG("connection failed - connect returned 0
+" );
            $self->error("SSL connect attempt failed because of handsh
+ake problems" );
            ${*$self}{'_SSL_opened'} = -1;
            return $self->fatal_ssl_error();
        }
    }

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I can see the cipher list being set before this 'for' loop. But I do not understand the code in this loop. Why does SSLeay::connect() fail and why is a READ performed on the socket? From debugs, I could see that this loop is executing more than once. After the READ is successful, there is a comment 'socket is ready, try non-blocking connect again after recomputing timeout'. Does this mean that there is some data on the socket (client/server cipher list?) and will be 'processed'? This example here http://search.cpan.org/~sampo/Net_SSLeay.pm-1.25/SSLeay.pm calls this function only once, which doesn't clarify things. Can someone please help me understand this.

IO::Socket::SSL version: 1.84

Net::SSLeay version: 1.21

Thanks & Regards,

In reply to Query regarding connect_SSL (IO::Socket::SSL.pm) by albus123

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