ESP8266 datasheet(108/117 Pages) ESPRESSIF

108 / 117 page

14. Sniffer Introduction

};

struct sniffer_buf2{

struct RxControl rx_ctrl;

u8 buf[112]; //may be 240, please refer to the real source code

u16 cnt;

u16 len;

//length of packet

};

Callback wifi_promiscuous_rx has two parameters (buf and len). len means the

length of buf, it can be: len = sizeof(struct sniffer_buf2), len = X * 10, len = sizeof(struct

RxControl):

Case of LEN == sizeof (struct sniffer_buf2)

•

buf contains structure sniffer_buf2: it is the management packet, it has 112

Bytes data.

•

sniffer_buf2.cnt is 1.

•

sniffer_buf2.len is the length of packet.

Case of LEN == X * 10

• buf contains structure sniffer_buf: this structure is reliable, data packets

represented by it has been veriﬁed by CRC.

•

sniffer_buf.cnt means the count of packets in buf. The value of len depends

on sniffer_buf.cnt.

- sniffer_buf.cnt==0, invalid buf; otherwise, len = 50 + cnt * 10

• sniffer_buf.buf contains the ﬁrst 36 Bytes of IEEE80211 packet. Starting from

sniffer_buf.lenseq[0], each structure lenseq represent a length information of

packet. lenseq[0] represents the length of ﬁrst packet. If there are two packets

where (sniffer_buf.cnt == 2), lenseq[1] represents the length of second

packet.

•

If sniffer_buf.cnt > 1, it is a AMPDU packet, head of each MPDU packets are

similar, so we only provide the length of each packet (from head of MAC packet to

FCS)

•

This structure contains: length of packet, MAC address of both sides of

communication, length of the head of packet.

Case of LEN == sizeof(struct RxControl)

•

buf contains structure RxControl; but this structure is not reliable, we can not get

neither MAC address of both sides of communication nor length of the head of

packet.

•

For AMPDU packet, we can not get the count of packets or the length of packet.

Espressif

100 104

2017.05

ESP8266 Datasheet(PDF) 108 Page - ESPRESSIF SYSTEMS (SHANGHAI) CO., LTD.

ESP8266 Datasheet(HTML) 108 Page - ESPRESSIF SYSTEMS (SHANGHAI) CO., LTD.

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL