蓝牙L2CAP剖析（二）

原创专注于无线通信的蓬勃 2016-05-10 17:42

构建AI未来，Arm计算平台无处不在 破解工业通信时延困局

关键字：bluetooth 蓝牙协议 HCI剖析 HCI概述 HCI笔记 LMP L2CAP SDP RFCOMM

作者：zhongjun

本着互相学习的目的，来分享此一系列的文章，欢迎转载，请注明作者，尊重版权，谢谢

文章有不当处请指正，共同学习

此系列目前这样打算：

LMP剖析 + 模拟源码：

HCI剖析 + 模拟源码：

L2CAP剖析 + 模拟源码

SDP剖析 + 模拟源码（未完成）

rfcomm剖析 + 模拟源码（未完成）

另外可以从蓝牙栏目访问我的CSDN：http://blog.csdn.net/XiaoXiaoPengBo/article/category/5998687

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华丽分割线，进入正题

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一,部分代码没有完成，只是模拟一个面向连接的从建立到断开的过程，另外，L2CAP的重点状态机和拆包重组没有模拟

bt_l2cap.h

/*
* This file is part of the L2CAP protocal.
* Data  :20160510
* Author: zhongjun
*
*/

#ifndef BT_L2CAP_H_H
#define BT_L2CAP_H_H

#include "bt_cfg.h"

#ifdef DEBUG_BT_L2CAP
#define DEBUG(x) {printf x;}
#define BT_L2CAP_DEBUG(x) DEBUG(x)
#else
#define BT_L2CAP_DEBUG(x) 
#endif
/* L2CAP CHANNEL */
#define L2CAP_SIG_CH 0x0001
#define L2CAP_CONLESS_CH 0x0002

/* L2CAP defaults */
#define L2CAP_DEFAULT_MTU	672
#define L2CAP_DEFAULT_FLUSH_TO	0xFFFF

/* UPPER LAYER PSM */
#define SDP_PSM 0x0001
/* L2CAP command codes */
#define L2CAP_COMMAND_REJ	0x01
#define L2CAP_CONN_REQ		0x02
#define L2CAP_CONN_RSP		0x03
#define L2CAP_CONF_REQ		0x04
#define L2CAP_CONF_RSP		0x05
#define L2CAP_DISCONN_REQ	0x06
#define L2CAP_DISCONN_RSP	0x07
#define L2CAP_ECHO_REQ		0x08
#define L2CAP_ECHO_RSP		0x09
#define L2CAP_INFO_REQ		0x0a
#define L2CAP_INFO_RSP		0x0b

/* connect result */
#define L2CAP_CR_SUCCESS	0x0000
#define L2CAP_CR_PEND		0x0001
#define L2CAP_CR_NOSUP_PSM	0x0002
#define L2CAP_CR_SEC_BLOCK	0x0003
#define L2CAP_CR_NO_RSR		0x0004
/* config result */
#define L2CAP_CONF_SUCCESS	0x0000
#define L2CAP_CONF_UNACCEPT	0x0001
#define L2CAP_CONF_REJECT	0x0002
#define L2CAP_CONF_UNKNOWN	0x0003

/* config option */
#define L2CAP_CONF_MTU		0x01
#define L2CAP_CONF_FLUSH_TO	0x02
#define L2CAP_CONF_QOS		0x03
#define L2CAP_CONF_RFC		0x04
#define L2CAP_CONF_RFC_MODE	0x04

#pragma pack(1)
/* L2CAP structures hdr*/
typedef struct {
	uint16_t	len;
	uint16_t	cid;
}L2CAP_PDU_HDR_Format;

typedef struct {
	L2CAP_PDU_HDR_Format sig_hdr;
	uint8_t		code;
	uint8_t		ident;
	uint16_t	len;
}L2CAP_SIG_HDR_Format;

/* L2CAP structures detail*/
typedef struct {
	L2CAP_SIG_HDR_Format com_hdr;
	uint16_t	psm;
	uint16_t	scid;
}L2CAP_Con_Req;

typedef struct {
	L2CAP_SIG_HDR_Format com_hdr;
	uint16_t	dst_cid;
	uint16_t	src_cid;
	uint16_t	result;
	uint16_t	status;
}L2CAP_Con_Rsp;

typedef struct {
	L2CAP_SIG_HDR_Format com_hdr;
	uint16_t	dst_cid;
	uint16_t	flags;
	uint8_t		data[0];
}L2CAP_Conf_Req;

typedef struct {
	L2CAP_SIG_HDR_Format com_hdr;
	uint16_t	src_cid;
	uint16_t	flags;
	uint16_t	result;
	uint8_t		data[0];
}L2CAP_Conf_Rsp;

typedef struct {
	L2CAP_PDU_HDR_Format com_hdr;
	uint8_t		data[0];
}L2CAP_Upper_Layer_data_Format;

typedef struct {
	L2CAP_SIG_HDR_Format com_hdr;
	uint16_t	dcid;
	uint16_t	scid;
}L2CAP_Discon_req;

typedef struct {
	L2CAP_SIG_HDR_Format com_hdr;
	uint16_t	dcid;
	uint16_t	scid;
}L2CAP_Discon_rsp;
#pragma pack()

/* API */
/* send pdu */
int L2CAP_Send_SIG_Con_Req(uint8_t ident,uint16_t psm,uint16_t scid);
int L2CAP_Send_SIG_Conf_Req(uint8_t ident,uint16_t dcid,uint16_t flags,uint8_t *conf_opt,uint8_t opt_len);
int L2CAP_Send_Upper_Layer_data(uint16_t cid,uint8_t *data,uint16_t length);
int L2CAP_Send_SIG_Discon_Req(uint8_t ident,uint16_t dcid,uint16_t scid);
int L2CAP_Send_PDU(uint8_t *PDU,uint32_t length);

/* reve pdu */
int L2CAP_Parse_PDU(uint8_t *PDU,uint32_t length);
int L2CAP_Parse_SIG_Con_Rsp_PDU(uint8_t *PDU,uint32_t length);
int L2CAP_Parse_SIG_Conf_Rsp_PDU(uint8_t *PDU,uint32_t length);
int L2CAP_Parse_SIG_Discon_Rsp_PDU(uint8_t *PDU,uint32_t length);
#endif

bt_l2cap.c

#include "bt_l2cap.h"

int L2CAP_Send_SIG_Con_Req(uint8_t ident,uint16_t psm,uint16_t scid)
{
	L2CAP_Con_Req PDU;
	PDU.com_hdr.sig_hdr.cid = L2CAP_SIG_CH;
	PDU.com_hdr.sig_hdr.len = sizeof(L2CAP_Con_Req) - sizeof(L2CAP_PDU_HDR_Format);

	PDU.com_hdr.code = L2CAP_CONN_REQ;
	PDU.com_hdr.ident = ident;
	PDU.com_hdr.len = sizeof(L2CAP_Con_Req) - sizeof(L2CAP_SIG_HDR_Format);

	PDU.psm = psm;
	PDU.scid = scid;
	L2CAP_Send_PDU((uint8_t *)&PDU,sizeof(L2CAP_Con_Req));
}
int L2CAP_Send_SIG_Conf_Req(uint8_t ident,uint16_t dcid,uint16_t flags,uint8_t *conf_opt,uint8_t opt_len)
{
	L2CAP_Conf_Req *PDU = (L2CAP_Conf_Req *)malloc(sizeof(L2CAP_Conf_Req) + opt_len);
	(PDU->com_hdr).sig_hdr.cid = L2CAP_SIG_CH;
	(PDU->com_hdr).sig_hdr.len = sizeof(L2CAP_Conf_Req) - sizeof(L2CAP_PDU_HDR_Format) + opt_len;
	
	(PDU->com_hdr).code = L2CAP_CONF_REQ;
	(PDU->com_hdr).ident = ident;
	(PDU->com_hdr).len = sizeof(L2CAP_Conf_Req) - sizeof(L2CAP_SIG_HDR_Format) + opt_len;
	
	PDU->dst_cid = dcid;
	PDU->flags = flags;
	memcpy(PDU->data,conf_opt,opt_len);

	L2CAP_Send_PDU(PDU,sizeof(L2CAP_Conf_Req) + opt_len);
}

int L2CAP_Send_Upper_Layer_data(uint16_t cid,uint8_t *data,uint16_t length)
{
	L2CAP_Upper_Layer_data_Format *PDU = (L2CAP_Upper_Layer_data_Format *)malloc(sizeof(L2CAP_Upper_Layer_data_Format) + length);
	(PDU->com_hdr).cid = cid;
	(PDU->com_hdr).len = sizeof(L2CAP_Upper_Layer_data_Format) + length;

	memcpy(PDU->data,data,length);	
	L2CAP_Send_PDU(PDU,sizeof(L2CAP_Upper_Layer_data_Format) + length);
}

int L2CAP_Send_SIG_Discon_Req(uint8_t ident,uint16_t dcid,uint16_t scid)
{
	L2CAP_Discon_req PDU;
	PDU.com_hdr.sig_hdr.cid = L2CAP_SIG_CH;
	PDU.com_hdr.sig_hdr.len = sizeof(L2CAP_Discon_req) - sizeof(L2CAP_PDU_HDR_Format);
	
	PDU.com_hdr.code = L2CAP_DISCONN_REQ;
	PDU.com_hdr.ident = ident;
	PDU.com_hdr.len = sizeof(L2CAP_Con_Req) - sizeof(L2CAP_SIG_HDR_Format);
	
	PDU.dcid = dcid;
	PDU.scid = scid;
	L2CAP_Send_PDU((uint8_t *)&PDU,sizeof(L2CAP_Con_Req));
}
int L2CAP_Send_PDU(uint8_t *PDU,uint32_t length)
{
	int index = 0;
	BT_L2CAP_DEBUG((" >> Send L2CAP REQ PDU:"));
	for(index = 0; index < length; index++)
	{
		BT_L2CAP_DEBUG(("0x%02x ",PDU[index]));
	}
	BT_L2CAP_DEBUG(("\n"));
}


int L2CAP_Parse_PDU(uint8_t *PDU,uint32_t length)
{
	L2CAP_PDU_HDR_Format *TMP_PDU = (L2CAP_PDU_HDR_Format *)PDU;
	if((TMP_PDU->cid) == L2CAP_SIG_CH)
	{
		uint8_t tmp_code;
		L2CAP_SIG_HDR_Format *pdu = (L2CAP_SIG_HDR_Format *)PDU;
		BT_L2CAP_DEBUG(("SIG PDU\n"));		
		tmp_code = pdu->code;
		switch(tmp_code)
		{
			case L2CAP_CONN_RSP:
			{
				BT_L2CAP_DEBUG(("L2CAP_CONN_RSP\n"));
				L2CAP_Parse_SIG_Con_Rsp_PDU(PDU,length);
				break;
			}
			case L2CAP_CONF_RSP:
			{
				BT_L2CAP_DEBUG(("L2CAP_CONF_RSP\n"));
				L2CAP_Parse_SIG_Conf_Rsp_PDU(PDU,length);
				break;
			}
			case L2CAP_DISCONN_RSP:
			{
				BT_L2CAP_DEBUG(("L2CAP_DISCONN_RSP\n"));
				L2CAP_Parse_SIG_Discon_Rsp_PDU(PDU,length);
				break;
			}
			default:
			{
				break;
			}
		}
		
	}
	else
	{
		//TODO
	}
}

int L2CAP_Parse_SIG_Con_Rsp_PDU(uint8_t *PDU,uint32_t length)
{
	L2CAP_Con_Rsp *tmp_pdu = (L2CAP_Con_Rsp *)PDU;
	if(tmp_pdu->result == L2CAP_CR_SUCCESS)
	{
		BT_L2CAP_DEBUG(("connect successful\n"));
	}
	else if(tmp_pdu->result == L2CAP_CR_PEND)
	{
		BT_L2CAP_DEBUG(("connect pending\n"));
	}
}

int L2CAP_Parse_SIG_Conf_Rsp_PDU(uint8_t *PDU,uint32_t length)
{
	L2CAP_Conf_Rsp *tmp_pdu = (L2CAP_Conf_Rsp *)PDU;
	if(tmp_pdu->result == L2CAP_CONF_SUCCESS)
	{
		BT_L2CAP_DEBUG(("config successful\n"));
	}
	else if(tmp_pdu->result == L2CAP_CONF_UNACCEPT)
	{
		BT_L2CAP_DEBUG(("config unaccept\n"));
	}
}

int L2CAP_Parse_SIG_Discon_Rsp_PDU(uint8_t *PDU,uint32_t length)
{
	
}

bt_cfg.h

#ifndef BT_LMP_CFG_H
#define BT_LMP_CFG_H

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#define DEBUG_BT_L2CAP

typedef unsigned char uint8_t;
typedef unsigned short uint16_t;
typedef unsigned int uint32_t;



typedef  char int8_t;
typedef  short int16_t;
typedef  int int32_t;

#undef NULL 
#if defined(__cplusplus)
#define NULL 0
#else
#define NULL ((void *)0)
#endif

#endif

main.c

#include <stdio.h>
#include "bt_l2cap.h"

int main()
{
	uint8_t con_rsp_pdu[] = {0x0C,0x00,0x01,0x00,0x03,0x79,0x08,0x00,0x06,0x08,0x40,0x00,0x00,0x00,0x00,0x00}; 
	uint8_t conf_option[] = {0x01,0x02,0xF4,0x01,0x02,0x02,0xFF,0xFF};
	uint8_t conf_rsp_pdu[] = {0x0E,0x00,0x01,0x00,0x05,0x7A,0x0A,0x00,0x40,0x00,0x00,0x00,0x00,0x00,0x01,0x02,0xF4,0x01};
	uint8_t upper_layer_data[] = {0x1,0x1,0x1,0x1,0x1,0x1};
	L2CAP_Send_SIG_Con_Req(0x79,SDP_PSM,0x40);
	L2CAP_Parse_PDU(con_rsp_pdu,sizeof(con_rsp_pdu));

	L2CAP_Send_SIG_Conf_Req(0x79,0x0806,0x0,conf_option,sizeof(conf_option));
	L2CAP_Parse_PDU(conf_rsp_pdu,sizeof(conf_rsp_pdu));

	L2CAP_Send_Upper_Layer_data(0x40,upper_layer_data,sizeof(upper_layer_data));

	L2CAP_Send_SIG_Discon_Req(0x79,0x40,0x0806);
}

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