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authorHendrik Brueckner <brueckner@linux.vnet.ibm.com>2009-04-21 23:26:23 +0000
committerDavid S. Miller <davem@davemloft.net>2009-04-23 04:04:33 -0700
commitb8942e3b6c4b35dda5e8ca75aec5e2f027fe39a9 (patch)
tree1d89b4fc4aa5d327c0c43feb4281b1a3aa6e0a23 /include/net/iucv
parent9d5c5d8f4105dc56ec10864b195dd1714f282c22 (diff)
af_iucv: Support data in IUCV msg parameter lists (IPRMDATA)
The patch allows to send and receive data in the parameter list of an iucv message. The parameter list is an arry of 8 bytes that are used by af_iucv as follows: 0..6 7 bytes for socket data and 7 1 byte to store the data length. Instead of storing the data length directly, the difference between 0xFF and the data length is used. This convention does not interfere with the existing use of PRM messages for shutting down the send direction of an AF_IUCV socket (shutdown() operation). Data lenghts greater than 7 (or PRM message byte 8 is less than 0xF8) denotes to special messages. Currently, the special SEND_SHUTDOWN message is supported only. To use IPRM messages, both communicators must set the IUCV_IPRMDATA flag during path negotiation, i.e. in iucv_connect() and path_pending(). To be compatible to older af_iucv implementations, sending PRM messages is controlled by the socket option SO_IPRMDATA_MSG. Receiving PRM messages does not depend on the socket option (but requires the IUCV_IPRMDATA path flag to be set). Sending/Receiving data in the parameter list improves performance for small amounts of data by reducing message_completion() interrupts and memory copy operations. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/iucv')
0 files changed, 0 insertions, 0 deletions