On Tue, Dec 08, 2009 at 02:54:43PM +0200, avital sela wrote: > Hello, > > I am testing a AES HW crypto driver I wrote. I test by setting up a > tunnel between the board and a Linux server and pinging packets from > the board to the server. > With my driver loaded everything works fine with small packets but > large packets (>1500) fail (100% packet loss). > I added some debug code to the standard crypto/cbc.c and noticed that > when I ping using -s1500 the encryption (aes-cbc) gets broken up to 3 > chuncks > sized 1456 , 16, 64. I also noticed that the iv for each of the > chunks is different. > Questions: > 1. Why are there 3 chunks with these sizes? Is this related to the > crypto subsystem or the ipsec one? The chunks 1456/64 is a product of the TCP stack. 16 is the IV added on by IPsec. > 2. How is the iv computed between each subsequent chunk? The last cipher (encrypted) block of a chunk should be used as the IV for the next chunk. Cheers, -- Visit Openswan at http://www.openswan.org/ Email: Herbert Xu ~{PmV>HI~} <herbert@xxxxxxxxxxxxxxxxxxx> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
