Hi Sye Loong, I am using a simulated sensor node in cooja. wismote is a simulated wireless sensor node which simulates a TI MSP430 with 16kB RAM and 128 kB Rom, so this suites in the class 1 category. Currently I am still in the state of getting tinydtls working on the TI MSP430.
Hauke On 08/27/2013 03:32 AM, Keoh, Sye Loong wrote: > Hi Hauke, > > What is a wismote? Do you have a use case for your work? and what are > the assumptions of the nodes in your network? Are they class 1 devices > as defined in the Terminology draft? > > Great that you are willing to contribute! > > cheers > Sye Loong > > -----Original Message----- From: Hauke Mehrtens > Sent: Monday, August 26, 2013 10:42 PM > To: Sye Loong Keoh > Cc: [email protected] ; [email protected] ; [email protected] > Subject: [SPAM?] Re: [Lwip] Notes on draft-tschofenig-lwig-tls-minimal-03 > > Hi Sye Loong, > > I am currently at implementing reordering, it seams to work, but it is > not committed to github yet. > > I am also sending only one message at a time, so a flight contains many > UDP packages. > > I am currently trying to get it to work in cooja on a simulated wismote, > the psk handshake already works, but I still have problems with the > ECDH_ECDSA handshake, something is probably wrong in the ecc code, on > x86 it works. Cooja also has a nice tool which shows the stack usage of > the application running. > > Too bad you can not give me access to your modified tinydtls version. > > Most of my code is at github, it misses some of the things that I am > currently working on and that are not cleaned up right now. > > I want to do some measurements similar to the ones, you did for the psk > case with ECDH_ECDSA for my master's thesis and I would like to get them > integrated into the draft. > > Hauke > > On 08/26/2013 12:04 PM, Keoh, Sye Loong wrote: >> Hi Hauke, >> >> Thank you for your interest in our draft. It is great to hear that you >> are extending TinyDTLS with raw public key support, and this is indeed >> the contribution that we needed in this document, as we only had >> performance and implementation details of PSK in TinyDTLS. >> >> At least in your implementation, we needed the re-ordering because >> messages were not sent using message flights. Each message is sent >> individually. >> >> I am sorry that the the modified TinyDTLS code cannot be made available >> due to some constraints that we have. But, we can discuss specific needs >> that you have. >> When you compile and flash the application to the hardware, you can get >> the RAM size measurement. >> >> Would be great if you could share your implementation details and >> measurements with us, so that they can be incorporated into our Internet >> Draft. >> >> cheers >> Sye Loong >> >>>>> >> Hi Hannes, >> >> I have some notes on >> https://tools.ietf.org/html/draft-tschofenig-lwig-tls-minimal-03 >> >> I am working on tinyDTLS and came across some problems. I extended it to >> support raw public keys with TLS_ECDHE_ECDSA_WITH_AES_128_CCM_8 on the >> SECP256R1 curve. The ECC code just supports this specific curve. >> >> The ClientHello without a cookie is now 99 Bytes big (value in UDP >> header) and on ieee802.15.4 it has to be fragmented somewhere. But to do >> fragmentation we have to store a state somewhere. >> >> For retransmission, instead of storing the whole message you could store >> the data which is needed to recreate the message. Data like the server >> certificate already has to be stored somewhere. I am planing to >> implement this. >> >> We have a high memory consumption in the handshake process, you could >> make it possible to be able to just do one handshake at a time, but have >> more than one DTLS session open at a time. All these DTLS session will >> then share a common memory space to store their temporary handshake >> data. I am planing to implement this. >> >> If you have a pretty reliable medium you could leave out implementation >> of reordering, the other peer will resend the messages if a message will >> be lost and then the client could start at the position where the >> package was lost again. This could save some ram to store the messages. >> >> Is the code of the modified tinyDTLS version and a more detailed >> description of the setup available somewhere? I am planing to so some >> measurements with tinyDTLS and raw public keys. How was the RAM size >> measurement done? >> >> As already discussed in the meeting the sizes for the tls implementation >> are pretty big. I haven't implemented a generic ASN.1 parser, I am just >> supporting one type of raw public key, so I am doing a memcmp() to >> ensure it is the one I excepted, then there is the public key at a >> constant offset. >> >> My tinyDTLS implementation with raw public keys and >> TLS_ECDHE_ECDSA_WITH_AES_128_CCM_8 on the SECP256R1 curve is about 30% >> bigger then the version just supporting PSK cipher. This measurement was >> done on a AMD64 system without any compiler optimization for size. I am >> planing to do a better measurement. >> >> Hauke >> >> [0]: https://github.com/hauke/tinydtls/tree/ecdh-merge > _______________________________________________ Lwip mailing list [email protected] https://www.ietf.org/mailman/listinfo/lwip
