Got a couple more (hopefully easy) questions. 1. What type do I use? The LDAP example uses ( 100 | 0x400 ). I know 0x400 is BIO_TYPE_SOURCE_SINK, but is 100 just a magic number pulled out of a hat? What magic number can I pull out of my hat for mine and how do I ensure it doesn't conflict with others (or does it not matter)?
2. Which callbacks can be left out? bss_fd.c sets the callback for "gets" to NULL, and the LDAP example implements it but it returns -1. So "gets" must be an optional callback, right? (Creating a custom BIO could be so easy if there was a short tutorial to answer some of these simple questions.) Phillip On Mon, Apr 12, 2010 at 10:27 AM, Phillip Hellewell <ssh...@gmail.com>wrote: > Thanks for the example. Yeah, my best idea so far was to look at existing > examples, such as bss_mem.c. One question I still have is which of the > BIO_CTRL_* commands does my ctrl function need to handle? bss_mem.c handles > about a dozen of them, but the example you gave me only handles > BIO_CTRL_FLUSH, so is that the only one I'm required to handle? > > Phillip > > > On Mon, Apr 12, 2010 at 10:15 AM, Howard Chu <h...@highlandsun.com> wrote: > >> Phillip Hellewell wrote: >> >>> Hi all, >>> >>> How do I implement my own BIO? Do I just create a function that returns >>> a >>> BIO_METHOD* with pointers to my custom functions? Is there any >>> documentation >>> on how to do this? >>> >>> I searched the mailing list and found that this question has been asked >>> before >>> but no one ever responds. The lack of documentation and responses leads >>> me to >>> believe that the BIO interface is not really meant to be used for >>> user-defined >>> I/O. >>> >>> 1999: http://marc.info/?l=ssl-users&m=91639275613495&w=2 >>> <http://marc.info/?l=ssl-users&m=91639275613495&w=2> >>> 2005: http://marc.info/?l=openssl-users&m=110624296809686&w=2 >>> <http://marc.info/?l=openssl-users&m=110624296809686&w=2> >>> 2008: http://marc.info/?l=openssl-dev&m=122959672906832&w=2 >>> <http://marc.info/?l=openssl-dev&m=122959672906832&w=2> >>> >>> Please, at least will someone respond with one of the following: >>> 1. "No, don't even try to do it. You're not supposed to." >>> 2. "Yes, you can do it but no one is going to help you. Just look at >>> some of >>> the files in crypto/bio/ and see if you can figure it out." >>> >> >> Some things are probably too easy to justify the time it takes to respond. >> In this case, define a BIO_METHOD struct with your handlers and just use it. >> >> One example is in OpenLDAP's libldap/tls_o.c. >> >> >> http://www.openldap.org/devel/cvsweb.cgi/~checkout~/libraries/libldap/tls_o.c?rev=1.16<http://www.openldap.org/devel/cvsweb.cgi/%7Echeckout%7E/libraries/libldap/tls_o.c?rev=1.16> >> >> -- >> -- Howard Chu >> CTO, Symas Corp. http://www.symas.com >> Director, Highland Sun http://highlandsun.com/hyc/ >> Chief Architect, OpenLDAP http://www.openldap.org/project/ >> > >
