On Sat, 2009-04-25 at 20:05 -0300, Gustavo F. Padovan wrote: > Hi all, > > I'm a accepted student for GSoC 2009 to work with BlueZ. I'm a > Computer Engineer student at University of Campinas (Brazil). > > In my project I'm going to implement the L2CAP Enhanced Retransmission > mode. That mode will permit retransmission of corrupted or lost > packets improving bluetooth experience on Linux. My mentors are Luiz > Augusto “Vudentz” von Dentz and Marcel Holtmann. > > That's my hack for the next four months, and if you wanna see what I'm > doing look at my git repo[1] and/or read my blog[2]. Also I'll send > reports of my work to this list approximately twice a month. > > Finally, I wanna thanks all the BlueZ devs for accept me on GSoC, I'm > very glad to work with BlueZ. And I wanna congratulate the other > students accepted on BlueZ. =) > > Regards. > > > [1] http://www.las.ic.unicamp.br/~gustavo/git/ > [2] http://padovan.org/ As part of my employers work in medical devices, I've been working on implementing enhanced L2CAP mode in the kernel. Since learning of Gustavo's acceptance into Google's SOC (congratulations!), I've been cleared to open up the work which I have thus far. Because our initial target is interoperability against a specific set of medical devices from outside vendors, my work thus far has been targeted against these devices. Enhanced L2CAP is fairly complex, and has multiple parts to it. To get the first round of compatibility going, I've taken such paths as limiting the local TX window to 1 outstanding SDU. Currently, the code is at a state where it successfully negotiates between enhanced/streaming/basic modes, opens a connection, and begins sending data. Much of the work I've done thus far has been splitting out the send/receive paths for the separate modes. There have been no significant changes in and code path, and no need to make any major changes to the existing data structures. Major points left to implement include: * Support for a TX windows > 1 On both send and receive, the code limits itself to only one outstanding l2cap SDU at a time. I have added a send and receive queue of skbuffs to a socket to support this, however this is unimplemented, and quite possibly duplicates code elsewhere in the kernel. * Add logic for the retransmission and monitor timers. Again, there are stubs in place for these timers, however the code is unimplemented. My next step will be basic retransmission support for lost packets. * Optimize the FCS computation. * Improve the L2CAP state machine Currently, the state machine described in section 8.6.5 of the L2CAP specification is mostly unimplemented. Currently, the code is branched off bluetooth-testing from last week. The tree is available via: git clone git://staticfree.info/git/el2cap I'd like to thank my friend Steve from the MIT Mobile Experience Lab for graciously hosting the code. My latest work is in the "retransmission" branch. Due to the increase in code size, I've split the files up into an l2cap sub-directory under net/bluetooth. I've not yet cloned Gustavo's repository, but I should be able to rebase the code off that as necessary. If there are any comments on style or implementation, I'd be happy to address them in the code. Hopefully, this can be used as base for Gustavo's SOC work so we can focus upon complete implementation of the Enhanced L2CAP specification and interoperability with other devices. --Nathan Holstein Lamprey Networks Inc. www.lampreynetworks.com -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
