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 <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/if_packet.h b/include/linux/if_packet.h
index ad09609..d4d3c82 100644
--- a/include/linux/if_packet.h
+++ b/include/linux/if_packet.h
@@ -43,6 +43,8 @@
#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 @@
#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: