From bbd6ef87c544d88c30e4b762b1b61ef267a7d279 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Mon, 14 Jul 2008 22:50:15 -0700 Subject: packet: support extensible, 64 bit clean mmaped ring structure The tpacket_hdr is not 64 bit clean due to use of an unsigned long and can't be extended because the following struct sockaddr_ll needs to be at a fixed offset. Add support for a version 2 tpacket protocol that removes these limitations. Userspace can query the header size through a new getsockopt option and change the protocol version through a setsockopt option. The changes needed to switch to the new protocol version are: 1. replace struct tpacket_hdr by struct tpacket2_hdr 2. query header len and save 3. set protocol version to 2 - set up ring as usual 4. for getting the sockaddr_ll, use (void *)hdr + TPACKET_ALIGN(hdrlen) instead of (void *)hdr + TPACKET_ALIGN(sizeof(struct tpacket_hdr)) Steps 2 and 4 can be omitted if the struct sockaddr_ll isn't needed. Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- include/linux/if_packet.h | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'include/linux') diff --git a/include/linux/if_packet.h b/include/linux/if_packet.h index ad09609227ff..d4d3c82448f5 100644 --- a/include/linux/if_packet.h +++ b/include/linux/if_packet.h @@ -43,6 +43,8 @@ struct sockaddr_ll #define PACKET_COPY_THRESH 7 #define PACKET_AUXDATA 8 #define PACKET_ORIGDEV 9 +#define PACKET_VERSION 10 +#define PACKET_HDRLEN 11 struct tpacket_stats { @@ -79,6 +81,25 @@ struct tpacket_hdr #define TPACKET_ALIGN(x) (((x)+TPACKET_ALIGNMENT-1)&~(TPACKET_ALIGNMENT-1)) #define TPACKET_HDRLEN (TPACKET_ALIGN(sizeof(struct tpacket_hdr)) + sizeof(struct sockaddr_ll)) +struct tpacket2_hdr +{ + __u32 tp_status; + __u32 tp_len; + __u32 tp_snaplen; + __u16 tp_mac; + __u16 tp_net; + __u32 tp_sec; + __u32 tp_nsec; +}; + +#define TPACKET2_HDRLEN (TPACKET_ALIGN(sizeof(struct tpacket2_hdr)) + sizeof(struct sockaddr_ll)) + +enum tpacket_versions +{ + TPACKET_V1, + TPACKET_V2, +}; + /* Frame structure: -- cgit v1.2.3-59-g8ed1b