[PATCH] packet.h: decrease packet capture length to 96 bytes

[Vitezslav Samel]

This size fits the comment above the definition and also
tcpdump has this default capture length.

Also reorganize the pkt_hdr strcture to have (almost) all
variables fitted into one CPU cacheline (should speed things up).

Signed-off-by: Vitezslav Samel 
---
 src/packet.h |   13 ++++++-------
 1 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/src/packet.h b/src/packet.h
index dd24533..f194db8 100644
--- a/src/packet.h
+++ b/src/packet.h
@@ -7,15 +7,14 @@ packet.h - external declarations for packet.c

***/

+#include "fltselect.h"
+
 /*
- * Number of bytes from captured packet to move into an aligned buffer.
+ * Number of bytes from captured packet to move into a buffer.
  * 96 bytes should be enough for the IP header, TCP/UDP/ICMP/whatever header
  * with reasonable numbers of options.
  */
-
-#include "fltselect.h"
-
-#define MAX_PACKET_SIZE 256	/* 256B should be enough to see all headers */
+#define MAX_PACKET_SIZE 96

#define INVALID_PACKET 0
 #define PACKET_OK 1
@@ -26,17 +25,17 @@ packet.h - external declarations for packet.c
 extern int isdnfd;

struct pkt_hdr {
-	char		pkt_buf[MAX_PACKET_SIZE];
    size_t		pkt_bufsize;
    char	       *pkt_payload;
    size_t		pkt_caplen;	/* bytes captured */
    size_t		pkt_len;	/* bytes on-the-wire */
-	unsigned short	pkt_protocol;	/* Physical layer protocol: ETH_P_* */
    int		pkt_ifindex;	/* Interface number */
+	unsigned short	pkt_protocol;	/* Physical layer protocol: ETH_P_* */
    unsigned short	pkt_hatype;	/* Header type: ARPHRD_* */
    unsigned char	pkt_pkttype;	/* Packet type: PACKET_OUTGOING, PACKET_BROADCAST, ... */
    unsigned char	pkt_halen;	/* Length of address */
    unsigned char	pkt_addr[8];	/* Physical layer address */
+	char		pkt_buf[MAX_PACKET_SIZE];
 };

#define PACKET_INIT(packet) \

[Nikola Pajkovsky]

Vitezslav Samel  writes:
> This size fits the comment above the definition and also
> tcpdump has this default capture length.
>
> Also reorganize the pkt_hdr strcture to have (almost) all
> variables fitted into one CPU cacheline (should speed things up).
> Signed-off-by: Vitezslav Samel
>
> src/packet.h |   13 ++++++-------
>  1 files changed, 6 insertions(+), 7 deletions(-)

applied. thanks.