Ethereal-users: [Ethereal-users] RE: Capture Header Decoding for Netxray (NetAsyst)

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From: "Ken Mann" <KMann@xxxxxxxxxxxxxxx>
Date: Thu, 27 Jan 2005 12:06:26 -0700
The structure below is what I have come up with. The noise level seems to use different units from the signal strength, 127 = 100%, 0xFF = ignore it. dummy2[2] appears to be set to 5 when the packet is WEP encrypted. The errorFlag value is either 1 or 5 when there is a problem with the packet (either CRC or WEP errors).
typedef struct
{
    UINT64  pktTimeuSec;
    SINT16  capLen;
    SINT16  pktLen;
    UCHAR   dummy[8];    // Appear to always be zero
    UCHAR errorFlag;     // 802.11 only
    UCHAR dummy2[3];     // Appear to always be zero
    UCHAR channel;       // 802.11 only
    UCHAR speed;         // 802.11 only
    UCHAR signalStrength;// 802.11 only
    UCHAR noiseLevel;    // FF (none reported) or 127 (0x7F) == 100%
    UCHAR dummy3[4];    // Meaning unknown, can be zeroed
    UCHAR srcMac[6];     // 802.11 only
    UCHAR dummy4[2];     // Meaning unknown, can be zeroed
} capHeaderTag;