On 23/01/15 11:20, Daniel Borkmann wrote:
On 01/23/2015 11:07 AM, Stathis Voukelatos wrote:This patch adds support the Ethernet Packet Sniffer H/W module developed by Linn Products Ltd and found in the IMG Pistachio SoC. The module allows Ethernet packets to be parsed, matched against a user-defined pattern and timestamped. It sits between a 100M Ethernet MAC and PHY and is completely passive with respect to Ethernet frames. Matched packet bytes and timestamp values are returned through a FIFO. Timestamps are provided to the module through an externally generated Gray-encoded counter. The command pattern for packet matching is stored in module RAM and consists of a sequence of 16-bit entries. Each entry includes an 8-bit command code and and 8-bit data value. Valid command codes are: 0 - Don't care 1 - Match: packet data must match command string byte 2 - Copy: packet data will be copied to FIFO 3 - Match/Stamp: if packet data matches string byte, a timestamp is copied into the FIFO 4 - Copy/Done: packet data will be copied into the FIFO. This command terminates the command string. The driver consists of two modules: - Core: it provides an API to user space using the Generic Netlink framework. Specific backend implementations, like the Ethernet Packet Sniffer, register one or more channels with the Core. For each channel a Genl family is created. User space can access a channel by sending Genl messages to the Genl family associated with the channel. Packet matching events are multicast. - Ethernet Packet Sniffer backend: provides the driver for the Linn Ethernet Packet Sniffer H/W modules. The split between a core and backend modules allows software-only implementations to be added for platforms where no H/W support is available. Based on 3.19-rc5 Signed-off-by: Stathis Voukelatos <stathis.voukelatos@xxxxxxxxxx>Please have a look at packet sockets, they offer already all the functionality (if not more) your driver interface to the user space resembles, are transparent to the underlying hardware, and easily can cope with 100Mbit. If I understand this correctly, you are effectively introducing a parallel API *next* to packet sockets to user space that we have to maintain forever ... Thanks !
Hello Daniel. Thank you for your feedback. Packet sockets could also be used for the driver interface to user space, however I think that both approaches would require the same amount of maintenance. We need to maintain a protocol consisting of a set of messages or commands that user space can use to communicate with the driver in order to configure the H/W and retrieve results. We could use packet sockets to send those messages too, but I thought netlink already provides a message exchange framework that we could make use of. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
