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LeafOS / LeafOS-Project / android_packages_modules_Bluetooth / d8b48c6221887ac8d651df642aaedfff7be482e4 / . / system / stack / l2cap / l2c_fcr.cc
blob: be6678561ab97d0f4b36b218d7debcdf5de05ec0 [file] [log] [blame]
/******************************************************************************
*
* Copyright 2004-2012 Broadcom Corporation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
******************************************************************************/
/******************************************************************************
*
* This file contains the L2CAP 1.2 Flow Control and retransmissions
* functions
*
******************************************************************************/
#include <base/logging.h>
#include <bluetooth/log.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "include/check.h"
#include "internal_include/bt_target.h"
#include "os/log.h"
#include "osi/include/allocator.h"
#include "stack/include/bt_hdr.h"
#include "stack/include/bt_types.h"
#include "stack/include/l2c_api.h"
#include "stack/include/l2cdefs.h"
#include "stack/l2cap/l2c_int.h"
/* Flag passed to retransmit_i_frames() when all packets should be retransmitted
*/
#define L2C_FCR_RETX_ALL_PKTS 0xFF
using namespace bluetooth;
/* this is the minimal offset required by OBX to process incoming packets */
static const uint16_t OBX_BUF_MIN_OFFSET = 4;
static const char* SAR_types[] = {"Unsegmented", "Start", "End",
"Continuation"};
static const char* SUP_types[] = {"RR", "REJ", "RNR", "SREJ"};
/* Look-up table for the CRC calculation */
static const unsigned short crctab[256] = {
0x0000, 0xc0c1, 0xc181, 0x0140, 0xc301, 0x03c0, 0x0280, 0xc241, 0xc601,
0x06c0, 0x0780, 0xc741, 0x0500, 0xc5c1, 0xc481, 0x0440, 0xcc01, 0x0cc0,
0x0d80, 0xcd41, 0x0f00, 0xcfc1, 0xce81, 0x0e40, 0x0a00, 0xcac1, 0xcb81,
0x0b40, 0xc901, 0x09c0, 0x0880, 0xc841, 0xd801, 0x18c0, 0x1980, 0xd941,
0x1b00, 0xdbc1, 0xda81, 0x1a40, 0x1e00, 0xdec1, 0xdf81, 0x1f40, 0xdd01,
0x1dc0, 0x1c80, 0xdc41, 0x1400, 0xd4c1, 0xd581, 0x1540, 0xd701, 0x17c0,
0x1680, 0xd641, 0xd201, 0x12c0, 0x1380, 0xd341, 0x1100, 0xd1c1, 0xd081,
0x1040, 0xf001, 0x30c0, 0x3180, 0xf141, 0x3300, 0xf3c1, 0xf281, 0x3240,
0x3600, 0xf6c1, 0xf781, 0x3740, 0xf501, 0x35c0, 0x3480, 0xf441, 0x3c00,
0xfcc1, 0xfd81, 0x3d40, 0xff01, 0x3fc0, 0x3e80, 0xfe41, 0xfa01, 0x3ac0,
0x3b80, 0xfb41, 0x3900, 0xf9c1, 0xf881, 0x3840, 0x2800, 0xe8c1, 0xe981,
0x2940, 0xeb01, 0x2bc0, 0x2a80, 0xea41, 0xee01, 0x2ec0, 0x2f80, 0xef41,
0x2d00, 0xedc1, 0xec81, 0x2c40, 0xe401, 0x24c0, 0x2580, 0xe541, 0x2700,
0xe7c1, 0xe681, 0x2640, 0x2200, 0xe2c1, 0xe381, 0x2340, 0xe101, 0x21c0,
0x2080, 0xe041, 0xa001, 0x60c0, 0x6180, 0xa141, 0x6300, 0xa3c1, 0xa281,
0x6240, 0x6600, 0xa6c1, 0xa781, 0x6740, 0xa501, 0x65c0, 0x6480, 0xa441,
0x6c00, 0xacc1, 0xad81, 0x6d40, 0xaf01, 0x6fc0, 0x6e80, 0xae41, 0xaa01,
0x6ac0, 0x6b80, 0xab41, 0x6900, 0xa9c1, 0xa881, 0x6840, 0x7800, 0xb8c1,
0xb981, 0x7940, 0xbb01, 0x7bc0, 0x7a80, 0xba41, 0xbe01, 0x7ec0, 0x7f80,
0xbf41, 0x7d00, 0xbdc1, 0xbc81, 0x7c40, 0xb401, 0x74c0, 0x7580, 0xb541,
0x7700, 0xb7c1, 0xb681, 0x7640, 0x7200, 0xb2c1, 0xb381, 0x7340, 0xb101,
0x71c0, 0x7080, 0xb041, 0x5000, 0x90c1, 0x9181, 0x5140, 0x9301, 0x53c0,
0x5280, 0x9241, 0x9601, 0x56c0, 0x5780, 0x9741, 0x5500, 0x95c1, 0x9481,
0x5440, 0x9c01, 0x5cc0, 0x5d80, 0x9d41, 0x5f00, 0x9fc1, 0x9e81, 0x5e40,
0x5a00, 0x9ac1, 0x9b81, 0x5b40, 0x9901, 0x59c0, 0x5880, 0x9841, 0x8801,
0x48c0, 0x4980, 0x8941, 0x4b00, 0x8bc1, 0x8a81, 0x4a40, 0x4e00, 0x8ec1,
0x8f81, 0x4f40, 0x8d01, 0x4dc0, 0x4c80, 0x8c41, 0x4400, 0x84c1, 0x8581,
0x4540, 0x8701, 0x47c0, 0x4680, 0x8641, 0x8201, 0x42c0, 0x4380, 0x8341,
0x4100, 0x81c1, 0x8081, 0x4040,
};
/*******************************************************************************
* Static local functions
*/
static bool process_reqseq(tL2C_CCB* p_ccb, uint16_t ctrl_word);
static void process_s_frame(tL2C_CCB* p_ccb, BT_HDR* p_buf, uint16_t ctrl_word);
static void process_i_frame(tL2C_CCB* p_ccb, BT_HDR* p_buf, uint16_t ctrl_word,
bool delay_ack);
static bool retransmit_i_frames(tL2C_CCB* p_ccb, uint8_t tx_seq);
static void prepare_I_frame(tL2C_CCB* p_ccb, BT_HDR* p_buf,
bool is_retransmission);
static bool do_sar_reassembly(tL2C_CCB* p_ccb, BT_HDR* p_buf,
uint16_t ctrl_word);
/*******************************************************************************
*
* Function l2c_fcr_updcrc
*
* Description This function computes the CRC using the look-up table.
*
* Returns CRC
*
******************************************************************************/
static unsigned short l2c_fcr_updcrc(unsigned short icrc, unsigned char* icp,
int icnt) {
unsigned short crc = icrc;
unsigned char* cp = icp;
int cnt = icnt;
while (cnt--) {
crc = ((crc >> 8) & 0xff) ^ crctab[(crc & 0xff) ^ *cp++];
}
return (crc);
}
/*******************************************************************************
*
* Function l2c_fcr_tx_get_fcs
*
* Description This function computes the CRC for a frame to be TXed.
*
* Returns CRC
*
******************************************************************************/
static uint16_t l2c_fcr_tx_get_fcs(BT_HDR* p_buf) {
uint8_t* p = ((uint8_t*)(p_buf + 1)) + p_buf->offset;
return (l2c_fcr_updcrc(L2CAP_FCR_INIT_CRC, p, p_buf->len));
}
/*******************************************************************************
*
* Function l2c_fcr_rx_get_fcs
*
* Description This function computes the CRC for a received frame.
*
* Returns CRC
*
******************************************************************************/
static uint16_t l2c_fcr_rx_get_fcs(BT_HDR* p_buf) {
uint8_t* p = ((uint8_t*)(p_buf + 1)) + p_buf->offset;
/* offset points past the L2CAP header, but the CRC check includes it */
p -= L2CAP_PKT_OVERHEAD;
return (
l2c_fcr_updcrc(L2CAP_FCR_INIT_CRC, p, p_buf->len + L2CAP_PKT_OVERHEAD));
}
/*******************************************************************************
*
* Function l2c_fcr_start_timer
*
* Description This function starts the (monitor or retransmission) timer.
*
* Returns -
*
******************************************************************************/
void l2c_fcr_start_timer(tL2C_CCB* p_ccb) {
CHECK(p_ccb != NULL);
uint32_t tout;
/* The timers which are in milliseconds */
if (p_ccb->fcrb.wait_ack) {
tout = (uint32_t)p_ccb->our_cfg.fcr.mon_tout;
} else {
tout = (uint32_t)p_ccb->our_cfg.fcr.rtrans_tout;
}
/* Only start a timer that was not started */
if (!alarm_is_scheduled(p_ccb->fcrb.mon_retrans_timer)) {
alarm_set_on_mloop(p_ccb->fcrb.mon_retrans_timer, tout,
l2c_ccb_timer_timeout, p_ccb);
}
}
/*******************************************************************************
*
* Function l2c_fcr_stop_timer
*
* Description This function stops the (monitor or transmission) timer.
*
* Returns -
*
******************************************************************************/
void l2c_fcr_stop_timer(tL2C_CCB* p_ccb) {
CHECK(p_ccb != NULL);
alarm_cancel(p_ccb->fcrb.mon_retrans_timer);
}
/*******************************************************************************
*
* Function l2c_fcr_cleanup
*
* Description This function cleans up the variable used for
* flow-control/retrans.
*
* Returns -
*
******************************************************************************/
void l2c_fcr_cleanup(tL2C_CCB* p_ccb) {
CHECK(p_ccb != NULL);
tL2C_FCRB* p_fcrb = &p_ccb->fcrb;
alarm_free(p_fcrb->mon_retrans_timer);
p_fcrb->mon_retrans_timer = NULL;
alarm_free(p_fcrb->ack_timer);
p_fcrb->ack_timer = NULL;
osi_free_and_reset((void**)&p_fcrb->p_rx_sdu);
fixed_queue_free(p_fcrb->waiting_for_ack_q, osi_free);
p_fcrb->waiting_for_ack_q = NULL;
fixed_queue_free(p_fcrb->srej_rcv_hold_q, osi_free);
p_fcrb->srej_rcv_hold_q = NULL;
fixed_queue_free(p_fcrb->retrans_q, osi_free);
p_fcrb->retrans_q = NULL;
memset(p_fcrb, 0, sizeof(tL2C_FCRB));
}
/*******************************************************************************
*
* Function l2c_fcr_clone_buf
*
* Description This function allocates and copies requested part of a
* buffer at a new-offset.
*
* Returns pointer to new buffer
*
******************************************************************************/
BT_HDR* l2c_fcr_clone_buf(BT_HDR* p_buf, uint16_t new_offset,
uint16_t no_of_bytes) {
CHECK(p_buf != NULL);
/*
* NOTE: We allocate extra L2CAP_FCS_LEN octets, in case we need to put
* the FCS (Frame Check Sequence) at the end of the buffer.
*/
uint16_t buf_size = no_of_bytes + sizeof(BT_HDR) + new_offset + L2CAP_FCS_LEN;
BT_HDR* p_buf2 = (BT_HDR*)osi_malloc(buf_size);
p_buf2->offset = new_offset;
p_buf2->len = no_of_bytes;
memcpy(((uint8_t*)(p_buf2 + 1)) + p_buf2->offset,
((uint8_t*)(p_buf + 1)) + p_buf->offset, no_of_bytes);
return (p_buf2);
}
/*******************************************************************************
*
* Function l2c_fcr_is_flow_controlled
*
* Description This function checks if the CCB is flow controlled by peer.
*
* Returns The control word
*
******************************************************************************/
bool l2c_fcr_is_flow_controlled(tL2C_CCB* p_ccb) {
CHECK(p_ccb != NULL);
if (p_ccb->peer_cfg.fcr.mode == L2CAP_FCR_ERTM_MODE) {
/* Check if remote side flowed us off or the transmit window is full */
if ((p_ccb->fcrb.remote_busy) ||
(fixed_queue_length(p_ccb->fcrb.waiting_for_ack_q) >=
p_ccb->peer_cfg.fcr.tx_win_sz)) {
return (true);
}
}
return (false);
}
/*******************************************************************************
*
* Function prepare_I_frame
*
* Description This function sets the FCR variables in an I-frame that is
* about to be sent to HCI for transmission. This may be the
* first time the I-frame is sent, or a retransmission
*
* Returns -
*
******************************************************************************/
static void prepare_I_frame(tL2C_CCB* p_ccb, BT_HDR* p_buf,
bool is_retransmission) {
CHECK(p_ccb != NULL);
CHECK(p_buf != NULL);
tL2C_FCRB* p_fcrb = &p_ccb->fcrb;
uint8_t* p;
uint16_t fcs;
uint16_t ctrl_word;
bool set_f_bit = p_fcrb->send_f_rsp;
p_fcrb->send_f_rsp = false;
if (is_retransmission) {
/* Get the old control word and clear out the old req_seq and F bits */
p = ((uint8_t*)(p_buf + 1)) + p_buf->offset + L2CAP_PKT_OVERHEAD;
STREAM_TO_UINT16(ctrl_word, p);
ctrl_word &= ~(L2CAP_FCR_REQ_SEQ_BITS + L2CAP_FCR_F_BIT);
} else {
ctrl_word = p_buf->layer_specific & L2CAP_FCR_SEG_BITS; /* SAR bits */
ctrl_word |=
(p_fcrb->next_tx_seq << L2CAP_FCR_TX_SEQ_BITS_SHIFT); /* Tx Seq */
p_fcrb->next_tx_seq = (p_fcrb->next_tx_seq + 1) & L2CAP_FCR_SEQ_MODULO;
}
/* Set the F-bit and reqseq only if using re-transmission mode */
if (p_ccb->peer_cfg.fcr.mode == L2CAP_FCR_ERTM_MODE) {
if (set_f_bit) ctrl_word |= L2CAP_FCR_F_BIT;
ctrl_word |= (p_fcrb->next_seq_expected) << L2CAP_FCR_REQ_SEQ_BITS_SHIFT;
p_fcrb->last_ack_sent = p_ccb->fcrb.next_seq_expected;
alarm_cancel(p_ccb->fcrb.ack_timer);
}
/* Set the control word */
p = ((uint8_t*)(p_buf + 1)) + p_buf->offset + L2CAP_PKT_OVERHEAD;
UINT16_TO_STREAM(p, ctrl_word);
/* Compute the FCS and add to the end of the buffer if not bypassed */
/* length field in l2cap header has to include FCS length */
p = ((uint8_t*)(p_buf + 1)) + p_buf->offset;
UINT16_TO_STREAM(p, p_buf->len + L2CAP_FCS_LEN - L2CAP_PKT_OVERHEAD);
/* Calculate the FCS */
fcs = l2c_fcr_tx_get_fcs(p_buf);
/* Point to the end of the buffer and put the FCS there */
/*
* NOTE: Here we assume the allocated buffer is large enough
* to include extra L2CAP_FCS_LEN octets at the end.
*/
p = ((uint8_t*)(p_buf + 1)) + p_buf->offset + p_buf->len;
UINT16_TO_STREAM(p, fcs);
p_buf->len += L2CAP_FCS_LEN;
if (is_retransmission) {
log::verbose(
"L2CAP eRTM ReTx I-frame CID: 0x{:04x} Len: {} SAR: {} TxSeq: {} "
"ReqSeq: {} F: {}",
p_ccb->local_cid, p_buf->len,
SAR_types[(ctrl_word & L2CAP_FCR_SAR_BITS) >> L2CAP_FCR_SAR_BITS_SHIFT],
(ctrl_word & L2CAP_FCR_TX_SEQ_BITS) >> L2CAP_FCR_TX_SEQ_BITS_SHIFT,
(ctrl_word & L2CAP_FCR_REQ_SEQ_BITS) >> L2CAP_FCR_REQ_SEQ_BITS_SHIFT,
(ctrl_word & L2CAP_FCR_F_BIT) >> L2CAP_FCR_F_BIT_SHIFT);
} else {
log::verbose(
"L2CAP eRTM Tx I-frame CID: 0x{:04x} Len: {} SAR: {:<12s} TxSeq: {} "
" ReqSeq: {} F: {}",
p_ccb->local_cid, p_buf->len,
SAR_types[(ctrl_word & L2CAP_FCR_SAR_BITS) >> L2CAP_FCR_SAR_BITS_SHIFT],
(ctrl_word & L2CAP_FCR_TX_SEQ_BITS) >> L2CAP_FCR_TX_SEQ_BITS_SHIFT,
(ctrl_word & L2CAP_FCR_REQ_SEQ_BITS) >> L2CAP_FCR_REQ_SEQ_BITS_SHIFT,
(ctrl_word & L2CAP_FCR_F_BIT) >> L2CAP_FCR_F_BIT_SHIFT);
}
/* Start the retransmission timer if not already running */
if (p_ccb->peer_cfg.fcr.mode == L2CAP_FCR_ERTM_MODE)
l2c_fcr_start_timer(p_ccb);
}
/*******************************************************************************
*
* Function l2c_fcr_send_S_frame
*
* Description This function formats and sends an S-frame for transmission.
*
* Returns -
*
******************************************************************************/
void l2c_fcr_send_S_frame(tL2C_CCB* p_ccb, uint16_t function_code,
uint16_t pf_bit) {
CHECK(p_ccb != NULL);
uint8_t* p;
uint16_t ctrl_word;
uint16_t fcs;
if ((!p_ccb->in_use) || (p_ccb->chnl_state != CST_OPEN)) return;
if (pf_bit == L2CAP_FCR_P_BIT) {
p_ccb->fcrb.wait_ack = true;
l2c_fcr_stop_timer(p_ccb); /* Restart the monitor timer */
l2c_fcr_start_timer(p_ccb);
}
/* Create the control word to use */
ctrl_word = (function_code << L2CAP_FCR_SUP_SHIFT) | L2CAP_FCR_S_FRAME_BIT;
ctrl_word |= (p_ccb->fcrb.next_seq_expected << L2CAP_FCR_REQ_SEQ_BITS_SHIFT);
ctrl_word |= pf_bit;
BT_HDR* p_buf = (BT_HDR*)osi_malloc(L2CAP_CMD_BUF_SIZE);
p_buf->offset = HCI_DATA_PREAMBLE_SIZE;
p_buf->len = L2CAP_PKT_OVERHEAD + L2CAP_FCR_OVERHEAD;
/* Set the pointer to the beginning of the data */
p = (uint8_t*)(p_buf + 1) + p_buf->offset;
/* Put in the L2CAP header */
UINT16_TO_STREAM(p, L2CAP_FCR_OVERHEAD + L2CAP_FCS_LEN);
UINT16_TO_STREAM(p, p_ccb->remote_cid);
UINT16_TO_STREAM(p, ctrl_word);
/* Compute the FCS and add to the end of the buffer if not bypassed */
fcs = l2c_fcr_tx_get_fcs(p_buf);
UINT16_TO_STREAM(p, fcs);
p_buf->len += L2CAP_FCS_LEN;
/* Now, the HCI transport header */
p_buf->layer_specific = L2CAP_NON_FLUSHABLE_PKT;
l2cu_set_acl_hci_header(p_buf, p_ccb);
if ((((ctrl_word & L2CAP_FCR_SUP_BITS) >> L2CAP_FCR_SUP_SHIFT) == 1) ||
(((ctrl_word & L2CAP_FCR_SUP_BITS) >> L2CAP_FCR_SUP_SHIFT) == 3)) {
log::warn(
"L2CAP eRTM Tx S-frame CID: 0x{:04x} ctrlword: 0x{:04x} Type: {} "
"ReqSeq: {} P: {} F: {}",
p_ccb->local_cid, ctrl_word,
SUP_types[(ctrl_word & L2CAP_FCR_SUP_BITS) >> L2CAP_FCR_SUP_SHIFT],
(ctrl_word & L2CAP_FCR_REQ_SEQ_BITS) >> L2CAP_FCR_REQ_SEQ_BITS_SHIFT,
(ctrl_word & L2CAP_FCR_P_BIT) >> L2CAP_FCR_P_BIT_SHIFT,
(ctrl_word & L2CAP_FCR_F_BIT) >> L2CAP_FCR_F_BIT_SHIFT);
log::warn("Buf Len: {}", p_buf->len);
} else {
log::verbose(
"L2CAP eRTM Tx S-frame CID: 0x{:04x} ctrlword: 0x{:04x} Type: {} "
"ReqSeq: {} P: {} F: {}",
p_ccb->local_cid, ctrl_word,
SUP_types[(ctrl_word & L2CAP_FCR_SUP_BITS) >> L2CAP_FCR_SUP_SHIFT],
(ctrl_word & L2CAP_FCR_REQ_SEQ_BITS) >> L2CAP_FCR_REQ_SEQ_BITS_SHIFT,
(ctrl_word & L2CAP_FCR_P_BIT) >> L2CAP_FCR_P_BIT_SHIFT,
(ctrl_word & L2CAP_FCR_F_BIT) >> L2CAP_FCR_F_BIT_SHIFT);
log::verbose("Buf Len: {}", p_buf->len);
}
l2c_link_check_send_pkts(p_ccb->p_lcb, 0, p_buf);
p_ccb->fcrb.last_ack_sent = p_ccb->fcrb.next_seq_expected;
alarm_cancel(p_ccb->fcrb.ack_timer);
}
/*******************************************************************************
*
* Function l2c_fcr_proc_pdu
*
* Description This function is the entry point for processing of a
* received PDU when in flow control and/or retransmission
* modes.
*
* Returns -
*
******************************************************************************/
void l2c_fcr_proc_pdu(tL2C_CCB* p_ccb, BT_HDR* p_buf) {
CHECK(p_ccb != NULL);
CHECK(p_buf != NULL);
uint8_t* p;
uint16_t fcs;
uint16_t min_pdu_len;
uint16_t ctrl_word;
/* Check the length */
min_pdu_len = (uint16_t)(L2CAP_FCS_LEN + L2CAP_FCR_OVERHEAD);
if (p_buf->len < min_pdu_len) {
log::warn("Rx L2CAP PDU: CID: 0x{:04x} Len too short: {}",
p_ccb->local_cid, p_buf->len);
osi_free(p_buf);
return;
}
/* Get the control word */
p = ((uint8_t*)(p_buf + 1)) + p_buf->offset;
STREAM_TO_UINT16(ctrl_word, p);
if (ctrl_word & L2CAP_FCR_S_FRAME_BIT) {
if ((((ctrl_word & L2CAP_FCR_SUP_BITS) >> L2CAP_FCR_SUP_SHIFT) == 1) ||
(((ctrl_word & L2CAP_FCR_SUP_BITS) >> L2CAP_FCR_SUP_SHIFT) == 3)) {
/* REJ or SREJ */
log::warn(
"L2CAP eRTM Rx S-frame: cid: 0x{:04x} Len: {} Type: {} ReqSeq: {} "
" P: {} F: {}",
p_ccb->local_cid, p_buf->len,
SUP_types[(ctrl_word & L2CAP_FCR_SUP_BITS) >> L2CAP_FCR_SUP_SHIFT],
(ctrl_word & L2CAP_FCR_REQ_SEQ_BITS) >> L2CAP_FCR_REQ_SEQ_BITS_SHIFT,
(ctrl_word & L2CAP_FCR_P_BIT) >> L2CAP_FCR_P_BIT_SHIFT,
(ctrl_word & L2CAP_FCR_F_BIT) >> L2CAP_FCR_F_BIT_SHIFT);
} else {
log::verbose(
"L2CAP eRTM Rx S-frame: cid: 0x{:04x} Len: {} Type: {} ReqSeq: {} "
" P: {} F: {}",
p_ccb->local_cid, p_buf->len,
SUP_types[(ctrl_word & L2CAP_FCR_SUP_BITS) >> L2CAP_FCR_SUP_SHIFT],
(ctrl_word & L2CAP_FCR_REQ_SEQ_BITS) >> L2CAP_FCR_REQ_SEQ_BITS_SHIFT,
(ctrl_word & L2CAP_FCR_P_BIT) >> L2CAP_FCR_P_BIT_SHIFT,
(ctrl_word & L2CAP_FCR_F_BIT) >> L2CAP_FCR_F_BIT_SHIFT);
}
} else {
log::verbose(
"L2CAP eRTM Rx I-frame: cid: 0x{:04x} Len: {} SAR: {:<12s} TxSeq: "
"{} ReqSeq: {} F: {}",
p_ccb->local_cid, p_buf->len,
SAR_types[(ctrl_word & L2CAP_FCR_SAR_BITS) >> L2CAP_FCR_SAR_BITS_SHIFT],
(ctrl_word & L2CAP_FCR_TX_SEQ_BITS) >> L2CAP_FCR_TX_SEQ_BITS_SHIFT,
(ctrl_word & L2CAP_FCR_REQ_SEQ_BITS) >> L2CAP_FCR_REQ_SEQ_BITS_SHIFT,
(ctrl_word & L2CAP_FCR_F_BIT) >> L2CAP_FCR_F_BIT_SHIFT);
}
log::verbose(
"eRTM Rx Nxt_tx_seq {}, Lst_rx_ack {}, Nxt_seq_exp {}, Lst_ack_snt {}, "
"wt_q.cnt {}, tries {}",
p_ccb->fcrb.next_tx_seq, p_ccb->fcrb.last_rx_ack,
p_ccb->fcrb.next_seq_expected, p_ccb->fcrb.last_ack_sent,
fixed_queue_length(p_ccb->fcrb.waiting_for_ack_q), p_ccb->fcrb.num_tries);
/* Verify FCS if using */
p = ((uint8_t*)(p_buf + 1)) + p_buf->offset + p_buf->len - L2CAP_FCS_LEN;
/* Extract and drop the FCS from the packet */
STREAM_TO_UINT16(fcs, p);
p_buf->len -= L2CAP_FCS_LEN;
if (l2c_fcr_rx_get_fcs(p_buf) != fcs) {
log::warn("Rx L2CAP PDU: CID: 0x{:04x} BAD FCS", p_ccb->local_cid);
osi_free(p_buf);
return;
}
/* Get the control word */
p = ((uint8_t*)(p_buf + 1)) + p_buf->offset;
STREAM_TO_UINT16(ctrl_word, p);
p_buf->len -= L2CAP_FCR_OVERHEAD;
p_buf->offset += L2CAP_FCR_OVERHEAD;
/* If we had a poll bit outstanding, check if we got a final response */
if (p_ccb->fcrb.wait_ack) {
/* If final bit not set, ignore the frame unless it is a polled S-frame */
if (!(ctrl_word & L2CAP_FCR_F_BIT)) {
if ((ctrl_word & L2CAP_FCR_P_BIT) &&
(ctrl_word & L2CAP_FCR_S_FRAME_BIT)) {
if (p_ccb->fcrb.srej_sent)
l2c_fcr_send_S_frame(p_ccb, L2CAP_FCR_SUP_SREJ, L2CAP_FCR_F_BIT);
else
l2c_fcr_send_S_frame(p_ccb, L2CAP_FCR_SUP_RR, L2CAP_FCR_F_BIT);
/* Got a poll while in wait_ack state, so re-start our timer with
* 1-second */
/* This is a small optimization... the monitor timer is 12 secs, but we
* saw */
/* that if the other side sends us a poll when we are waiting for a
* final, */
/* then it speeds up recovery significantly if we poll it back soon
* after its poll. */
alarm_set_on_mloop(p_ccb->fcrb.mon_retrans_timer, BT_1SEC_TIMEOUT_MS,
l2c_ccb_timer_timeout, p_ccb);
}
osi_free(p_buf);
return;
}
p_ccb->fcrb.wait_ack = false;
/* P and F are mutually exclusive */
if (ctrl_word & L2CAP_FCR_S_FRAME_BIT) ctrl_word &= ~L2CAP_FCR_P_BIT;
if (fixed_queue_is_empty(p_ccb->fcrb.waiting_for_ack_q))
p_ccb->fcrb.num_tries = 0;
l2c_fcr_stop_timer(p_ccb);
} else {
/* Otherwise, ensure the final bit is ignored */
ctrl_word &= ~L2CAP_FCR_F_BIT;
}
/* Process receive sequence number */
if (!process_reqseq(p_ccb, ctrl_word)) {
osi_free(p_buf);
return;
}
/* Process based on whether it is an S-frame or an I-frame */
if (ctrl_word & L2CAP_FCR_S_FRAME_BIT)
process_s_frame(p_ccb, p_buf, ctrl_word);
else
process_i_frame(p_ccb, p_buf, ctrl_word, false);
/* Return if the channel got disconnected by a bad packet or max
* retransmissions */
if ((!p_ccb->in_use) || (p_ccb->chnl_state != CST_OPEN)) return;
/* If we have some buffers held while doing SREJ, and SREJ has cleared,
* process them now */
if ((!p_ccb->fcrb.srej_sent) &&
(!fixed_queue_is_empty(p_ccb->fcrb.srej_rcv_hold_q))) {
fixed_queue_t* temp_q = p_ccb->fcrb.srej_rcv_hold_q;
p_ccb->fcrb.srej_rcv_hold_q = fixed_queue_new(SIZE_MAX);
while ((p_buf = (BT_HDR*)fixed_queue_try_dequeue(temp_q)) != NULL) {
if (p_ccb->in_use && (p_ccb->chnl_state == CST_OPEN)) {
/* Get the control word */
p = ((uint8_t*)(p_buf + 1)) + p_buf->offset - L2CAP_FCR_OVERHEAD;
STREAM_TO_UINT16(ctrl_word, p);
log::verbose(
"l2c_fcr_proc_pdu() CID: 0x{:04x} Process Buffer from SREJ_Hold_Q "
" TxSeq: {} Expected_Seq: {}",
p_ccb->local_cid,
(ctrl_word & L2CAP_FCR_TX_SEQ_BITS) >> L2CAP_FCR_TX_SEQ_BITS_SHIFT,
p_ccb->fcrb.next_seq_expected);
/* Process the SREJ held I-frame, but do not send an RR for each
* individual frame */
process_i_frame(p_ccb, p_buf, ctrl_word, true);
} else
osi_free(p_buf);
/* If more frames were lost during SREJ, send a REJ */
if (p_ccb->fcrb.rej_after_srej) {
p_ccb->fcrb.rej_after_srej = false;
p_ccb->fcrb.rej_sent = true;
l2c_fcr_send_S_frame(p_ccb, L2CAP_FCR_SUP_REJ, 0);
}
}
fixed_queue_free(temp_q, NULL);
/* Now, if needed, send one RR for the whole held queue */
if ((!p_ccb->fcrb.rej_sent) && (!p_ccb->fcrb.srej_sent) &&
(p_ccb->fcrb.next_seq_expected != p_ccb->fcrb.last_ack_sent))
l2c_fcr_send_S_frame(p_ccb, L2CAP_FCR_SUP_RR, 0);
else {
log::verbose(
"l2c_fcr_proc_pdu() not sending RR CID: 0x{:04x} local_busy:{} "
"rej_sent:{} srej_sent:{} Expected_Seq:{} Last_Ack:{}",
p_ccb->local_cid, 0, p_ccb->fcrb.rej_sent, p_ccb->fcrb.srej_sent,
p_ccb->fcrb.next_seq_expected, p_ccb->fcrb.last_ack_sent);
}
}
/* If a window has opened, check if we can send any more packets */
if ((!fixed_queue_is_empty(p_ccb->fcrb.retrans_q) ||
!fixed_queue_is_empty(p_ccb->xmit_hold_q)) &&
(!p_ccb->fcrb.wait_ack) && (!l2c_fcr_is_flow_controlled(p_ccb))) {
l2c_link_check_send_pkts(p_ccb->p_lcb, 0, NULL);
}
}
/*******************************************************************************
*
* Function l2c_lcc_proc_pdu
*
* Description This function is the entry point for processing of a
* received PDU when in LE Coc flow control modes.
*
* Returns -
*
******************************************************************************/
void l2c_lcc_proc_pdu(tL2C_CCB* p_ccb, BT_HDR* p_buf) {
CHECK(p_ccb != NULL);
CHECK(p_buf != NULL);
uint8_t* p = (uint8_t*)(p_buf + 1) + p_buf->offset;
uint16_t sdu_length;
BT_HDR* p_data = NULL;
/* Buffer length should not exceed local mps */
if (p_buf->len > p_ccb->local_conn_cfg.mps) {
log::error("buffer length={} exceeds local mps={}. Drop and disconnect.",
p_buf->len, p_ccb->local_conn_cfg.mps);
/* Discard the buffer and disconnect*/
osi_free(p_buf);
l2cu_disconnect_chnl(p_ccb);
return;
}
if (p_ccb->is_first_seg) {
if (p_buf->len < sizeof(sdu_length)) {
log::error("buffer length={} too small. Need at least 2.", p_buf->len);
/* Discard the buffer */
osi_free(p_buf);
return;
}
STREAM_TO_UINT16(sdu_length, p);
/* Check the SDU Length with local MTU size */
if (sdu_length > p_ccb->local_conn_cfg.mtu) {
log::error("sdu length={} exceeds local mtu={}. Drop and disconnect.",
sdu_length, p_ccb->local_conn_cfg.mtu);
/* Discard the buffer and disconnect*/
osi_free(p_buf);
l2cu_disconnect_chnl(p_ccb);
return;
}
p_buf->len -= sizeof(sdu_length);
p_buf->offset += sizeof(sdu_length);
if (sdu_length < p_buf->len) {
log::error("Invalid sdu_length: {}", sdu_length);
/* Discard the buffer */
osi_free(p_buf);
return;
}
p_data = (BT_HDR*)osi_malloc(BT_HDR_SIZE + sdu_length);
if (p_data == NULL) {
osi_free(p_buf);
return;
}
p_ccb->ble_sdu = p_data;
p_data->len = 0;
p_ccb->ble_sdu_length = sdu_length;
log::verbose("SDU Length = {}", sdu_length);
p_data->offset = 0;
} else {
p_data = p_ccb->ble_sdu;
if (p_data == NULL) {
osi_free(p_buf);
return;
}
if (p_buf->len > (p_ccb->ble_sdu_length - p_data->len)) {
log::error("buffer length={} too big. max={}. Dropped", p_data->len,
(p_ccb->ble_sdu_length - p_data->len));
osi_free(p_buf);
/* Throw away all pending fragments and disconnects */
p_ccb->is_first_seg = true;
osi_free(p_ccb->ble_sdu);
p_ccb->ble_sdu = NULL;
p_ccb->ble_sdu_length = 0;
l2cu_disconnect_chnl(p_ccb);
return;
}
}
memcpy((uint8_t*)(p_data + 1) + p_data->offset + p_data->len,
(uint8_t*)(p_buf + 1) + p_buf->offset, p_buf->len);
p_data->len += p_buf->len;
p = (uint8_t*)(p_data + 1) + p_data->offset;
if (p_data->len == p_ccb->ble_sdu_length) {
l2c_csm_execute(p_ccb, L2CEVT_L2CAP_DATA, p_data);
p_ccb->is_first_seg = true;
p_ccb->ble_sdu = NULL;
p_ccb->ble_sdu_length = 0;
} else if (p_data->len < p_ccb->ble_sdu_length) {
p_ccb->is_first_seg = false;
}
osi_free(p_buf);
return;
}
/*******************************************************************************
*
* Function l2c_fcr_proc_tout
*
* Description Handle a timeout. We should be in error recovery state.
*
* Returns -
*
******************************************************************************/
void l2c_fcr_proc_tout(tL2C_CCB* p_ccb) {
CHECK(p_ccb != NULL);
log::verbose(
"l2c_fcr_proc_tout: CID: 0x{:04x} num_tries: {} (max: {}) wait_ack: "
"{} ack_q_count: {}",
p_ccb->local_cid, p_ccb->fcrb.num_tries, p_ccb->peer_cfg.fcr.max_transmit,
p_ccb->fcrb.wait_ack, fixed_queue_length(p_ccb->fcrb.waiting_for_ack_q));
if ((p_ccb->peer_cfg.fcr.max_transmit != 0) &&
(++p_ccb->fcrb.num_tries > p_ccb->peer_cfg.fcr.max_transmit)) {
l2cu_disconnect_chnl(p_ccb);
} else {
if (!p_ccb->fcrb.srej_sent && !p_ccb->fcrb.rej_sent) {
l2c_fcr_send_S_frame(p_ccb, L2CAP_FCR_SUP_RR, L2CAP_FCR_P_BIT);
}
}
}
/*******************************************************************************
*
* Function l2c_fcr_proc_ack_tout
*
* Description Send RR/RNR if we have not acked I frame
*
* Returns -
*
******************************************************************************/
void l2c_fcr_proc_ack_tout(tL2C_CCB* p_ccb) {
CHECK(p_ccb != NULL);
log::verbose(
"l2c_fcr_proc_ack_tout: CID: 0x{:04x} State: {} Wack:{} Rq:{} "
"Acked:{}",
p_ccb->local_cid, p_ccb->chnl_state, p_ccb->fcrb.wait_ack,
p_ccb->fcrb.next_seq_expected, p_ccb->fcrb.last_ack_sent);
if ((p_ccb->chnl_state == CST_OPEN) && (!p_ccb->fcrb.wait_ack) &&
(p_ccb->fcrb.last_ack_sent != p_ccb->fcrb.next_seq_expected)) {
l2c_fcr_send_S_frame(p_ccb, L2CAP_FCR_SUP_RR, 0);
}
}
/*******************************************************************************
*
* Function process_reqseq
*
* Description Handle receive sequence number
*
* Returns -
*
******************************************************************************/
static bool process_reqseq(tL2C_CCB* p_ccb, uint16_t ctrl_word) {
CHECK(p_ccb != NULL);
tL2C_FCRB* p_fcrb = &p_ccb->fcrb;
uint8_t req_seq, num_bufs_acked, xx;
uint16_t ls;
uint16_t full_sdus_xmitted;
/* Receive sequence number does not ack anything for SREJ with P-bit set to
* zero */
if ((ctrl_word & L2CAP_FCR_S_FRAME_BIT) &&
((ctrl_word & L2CAP_FCR_SUP_BITS) ==
(L2CAP_FCR_SUP_SREJ << L2CAP_FCR_SUP_SHIFT)) &&
((ctrl_word & L2CAP_FCR_P_BIT) == 0)) {
/* If anything still waiting for ack, restart the timer if it was stopped */
if (!fixed_queue_is_empty(p_fcrb->waiting_for_ack_q))
l2c_fcr_start_timer(p_ccb);
return (true);
}
/* Extract the receive sequence number from the control word */
req_seq =
(ctrl_word & L2CAP_FCR_REQ_SEQ_BITS) >> L2CAP_FCR_REQ_SEQ_BITS_SHIFT;
num_bufs_acked = (req_seq - p_fcrb->last_rx_ack) & L2CAP_FCR_SEQ_MODULO;
/* Verify the request sequence is in range before proceeding */
if (num_bufs_acked > fixed_queue_length(p_fcrb->waiting_for_ack_q)) {
/* The channel is closed if ReqSeq is not in range */
log::warn(
"L2CAP eRTM Frame BAD Req_Seq - ctrl_word: 0x{:04x} req_seq 0x{:02x} "
"last_rx_ack: 0x{:02x} QCount: {}",
ctrl_word, req_seq, p_fcrb->last_rx_ack,
fixed_queue_length(p_fcrb->waiting_for_ack_q));
l2cu_disconnect_chnl(p_ccb);
return (false);
}
p_fcrb->last_rx_ack = req_seq;
/* Now we can release all acknowledged frames, and restart the retransmission
* timer if needed */
if (num_bufs_acked != 0) {
p_fcrb->num_tries = 0;
full_sdus_xmitted = 0;
for (xx = 0; xx < num_bufs_acked; xx++) {
BT_HDR* p_tmp =
(BT_HDR*)fixed_queue_try_dequeue(p_fcrb->waiting_for_ack_q);
ls = p_tmp->layer_specific & L2CAP_FCR_SAR_BITS;
if ((ls == L2CAP_FCR_UNSEG_SDU) || (ls == L2CAP_FCR_END_SDU))
full_sdus_xmitted++;
osi_free(p_tmp);
}
/* If we are still in a wait_ack state, do not mess with the timer */
if (!p_ccb->fcrb.wait_ack) l2c_fcr_stop_timer(p_ccb);
/* Check if we need to call the "packet_sent" callback */
if ((p_ccb->p_rcb) && (p_ccb->p_rcb->api.pL2CA_TxComplete_Cb) &&
(full_sdus_xmitted)) {
/* Special case for eRTM, if all packets sent, send 0xFFFF */
if (fixed_queue_is_empty(p_fcrb->waiting_for_ack_q) &&
fixed_queue_is_empty(p_ccb->xmit_hold_q)) {
full_sdus_xmitted = 0xFFFF;
}
(*p_ccb->p_rcb->api.pL2CA_TxComplete_Cb)(p_ccb->local_cid,
full_sdus_xmitted);
}
}
/* If anything still waiting for ack, restart the timer if it was stopped */
if (!fixed_queue_is_empty(p_fcrb->waiting_for_ack_q))
l2c_fcr_start_timer(p_ccb);
return (true);
}
/*******************************************************************************
*
* Function process_s_frame
*
* Description Process an S frame
*
* Returns -
*
******************************************************************************/
static void process_s_frame(tL2C_CCB* p_ccb, BT_HDR* p_buf,
uint16_t ctrl_word) {
CHECK(p_ccb != NULL);
CHECK(p_buf != NULL);
tL2C_FCRB* p_fcrb = &p_ccb->fcrb;
uint16_t s_frame_type =
(ctrl_word & L2CAP_FCR_SUP_BITS) >> L2CAP_FCR_SUP_SHIFT;
bool remote_was_busy;
bool all_ok = true;
if (p_buf->len != 0) {
log::warn("Incorrect S-frame Length ({})", p_buf->len);
}
log::verbose("process_s_frame ctrl_word 0x{:04x} fcrb_remote_busy:{}",
ctrl_word, p_fcrb->remote_busy);
if (ctrl_word & L2CAP_FCR_P_BIT) {
p_fcrb->rej_sent = false; /* After checkpoint, we can send anoher REJ */
p_fcrb->send_f_rsp = true; /* Set a flag in case an I-frame is pending */
}
switch (s_frame_type) {
case L2CAP_FCR_SUP_RR:
remote_was_busy = p_fcrb->remote_busy;
p_fcrb->remote_busy = false;
if ((ctrl_word & L2CAP_FCR_F_BIT) || (remote_was_busy))
all_ok = retransmit_i_frames(p_ccb, L2C_FCR_RETX_ALL_PKTS);
break;
case L2CAP_FCR_SUP_REJ:
p_fcrb->remote_busy = false;
all_ok = retransmit_i_frames(p_ccb, L2C_FCR_RETX_ALL_PKTS);
break;
case L2CAP_FCR_SUP_RNR:
p_fcrb->remote_busy = true;
l2c_fcr_stop_timer(p_ccb);
break;
case L2CAP_FCR_SUP_SREJ:
p_fcrb->remote_busy = false;
all_ok = retransmit_i_frames(
p_ccb, (uint8_t)((ctrl_word & L2CAP_FCR_REQ_SEQ_BITS) >>
L2CAP_FCR_REQ_SEQ_BITS_SHIFT));
break;
}
if (all_ok) {
/* If polled, we need to respond with F-bit. Note, we may have sent a
* I-frame with the F-bit */
if (p_fcrb->send_f_rsp) {
if (p_fcrb->srej_sent)
l2c_fcr_send_S_frame(p_ccb, L2CAP_FCR_SUP_SREJ, L2CAP_FCR_F_BIT);
else
l2c_fcr_send_S_frame(p_ccb, L2CAP_FCR_SUP_RR, L2CAP_FCR_F_BIT);
p_fcrb->send_f_rsp = false;
}
} else {
log::verbose("process_s_frame hit_max_retries");
}
osi_free(p_buf);
}
/*******************************************************************************
*
* Function process_i_frame
*
* Description Process an I frame
*
* Returns -
*
******************************************************************************/
static void process_i_frame(tL2C_CCB* p_ccb, BT_HDR* p_buf, uint16_t ctrl_word,
bool delay_ack) {
CHECK(p_ccb != NULL);
CHECK(p_buf != NULL);
tL2C_FCRB* p_fcrb = &p_ccb->fcrb;
uint8_t tx_seq, num_lost, num_to_ack, next_srej;
/* If we were doing checkpoint recovery, first retransmit all unacked I-frames
*/
if (ctrl_word & L2CAP_FCR_F_BIT) {
if (!retransmit_i_frames(p_ccb, L2C_FCR_RETX_ALL_PKTS)) {
osi_free(p_buf);
return;
}
}
/* Extract the sequence number */
tx_seq = (ctrl_word & L2CAP_FCR_TX_SEQ_BITS) >> L2CAP_FCR_TX_SEQ_BITS_SHIFT;
/* Check if tx-sequence is the expected one */
if (tx_seq != p_fcrb->next_seq_expected) {
num_lost = (tx_seq - p_fcrb->next_seq_expected) & L2CAP_FCR_SEQ_MODULO;
/* Is the frame a duplicate ? If so, just drop it */
if (num_lost >= p_ccb->our_cfg.fcr.tx_win_sz) {
/* Duplicate - simply drop it */
log::warn(
"process_i_frame() Dropping Duplicate Frame tx_seq:{} ExpectedTxSeq "
"{}",
tx_seq, p_fcrb->next_seq_expected);
osi_free(p_buf);
} else {
log::warn(
"process_i_frame() CID: 0x{:04x} Lost: {} tx_seq:{} ExpTxSeq {} "
"Rej: {} SRej: {}",
p_ccb->local_cid, num_lost, tx_seq, p_fcrb->next_seq_expected,
p_fcrb->rej_sent, p_fcrb->srej_sent);
if (p_fcrb->srej_sent) {
/* If SREJ sent, save the frame for later processing as long as it is in
* sequence */
next_srej =
(((BT_HDR*)fixed_queue_try_peek_last(p_fcrb->srej_rcv_hold_q))
->layer_specific +
1) &
L2CAP_FCR_SEQ_MODULO;
if ((tx_seq == next_srej) &&
(fixed_queue_length(p_fcrb->srej_rcv_hold_q) <
p_ccb->our_cfg.fcr.tx_win_sz)) {
log::verbose(
"process_i_frame() Lost: {} tx_seq:{} ExpTxSeq {} Rej: {} "
"SRej1",
num_lost, tx_seq, p_fcrb->next_seq_expected, p_fcrb->rej_sent);
p_buf->layer_specific = tx_seq;
fixed_queue_enqueue(p_fcrb->srej_rcv_hold_q, p_buf);
} else {
log::warn(
"process_i_frame() CID: 0x{:04x} frame dropped in Srej Sent "
"next_srej:{} hold_q.count:{} win_sz:{}",
p_ccb->local_cid, next_srej,
fixed_queue_length(p_fcrb->srej_rcv_hold_q),
p_ccb->our_cfg.fcr.tx_win_sz);
p_fcrb->rej_after_srej = true;
osi_free(p_buf);
}
} else if (p_fcrb->rej_sent) {
log::warn(
"process_i_frame() CID: 0x{:04x} Lost: {} tx_seq:{} ExpTxSeq {} "
" Rej: 1 SRej: {}",
p_ccb->local_cid, num_lost, tx_seq, p_fcrb->next_seq_expected,
p_fcrb->srej_sent);
/* If REJ sent, just drop the frame */
osi_free(p_buf);
} else {
log::verbose(
"process_i_frame() CID: 0x{:04x} tx_seq:{} ExpTxSeq {} Rej: {}",
p_ccb->local_cid, tx_seq, p_fcrb->next_seq_expected,
p_fcrb->rej_sent);
/* If only one lost, we will send SREJ, otherwise we will send REJ */
if (num_lost > 1) {
osi_free(p_buf);
p_fcrb->rej_sent = true;
l2c_fcr_send_S_frame(p_ccb, L2CAP_FCR_SUP_REJ, 0);
} else {
if (!fixed_queue_is_empty(p_fcrb->srej_rcv_hold_q)) {
log::error(
"process_i_frame() CID: 0x{:04x} sending SREJ tx_seq:{} "
"hold_q.count:{}",
p_ccb->local_cid, tx_seq,
fixed_queue_length(p_fcrb->srej_rcv_hold_q));
}
p_buf->layer_specific = tx_seq;
fixed_queue_enqueue(p_fcrb->srej_rcv_hold_q, p_buf);
p_fcrb->srej_sent = true;
l2c_fcr_send_S_frame(p_ccb, L2CAP_FCR_SUP_SREJ, 0);
}
alarm_cancel(p_ccb->fcrb.ack_timer);
}
}
return;
}
/* Seq number is the next expected. Clear possible reject exception in case it
* occured */
p_fcrb->rej_sent = p_fcrb->srej_sent = false;
/* Adjust the next_seq, so that if the upper layer sends more data in the
callback
context, the received frame is acked by an I-frame. */
p_fcrb->next_seq_expected = (tx_seq + 1) & L2CAP_FCR_SEQ_MODULO;
/* If any SAR problem in eRTM mode, spec says disconnect. */
if (!do_sar_reassembly(p_ccb, p_buf, ctrl_word)) {
log::warn("process_i_frame() CID: 0x{:04x} reassembly failed",
p_ccb->local_cid);
l2cu_disconnect_chnl(p_ccb);
return;
}
/* RR optimization - if peer can still send us more, then start an ACK timer
*/
num_to_ack = (p_fcrb->next_seq_expected - p_fcrb->last_ack_sent) &
L2CAP_FCR_SEQ_MODULO;
if (num_to_ack < p_ccb->fcrb.max_held_acks) delay_ack = true;
/* We should neve never ack frame if we are not in OPEN state */
if ((num_to_ack != 0) && p_ccb->in_use && (p_ccb->chnl_state == CST_OPEN)) {
/* If no frames are awaiting transmission or are held, send an RR or RNR
* S-frame for ack */
if (delay_ack) {
/* If it is the first I frame we did not ack, start ack timer */
if (!alarm_is_scheduled(p_ccb->fcrb.ack_timer)) {
alarm_set_on_mloop(p_ccb->fcrb.ack_timer, L2CAP_FCR_ACK_TIMEOUT_MS,
l2c_fcrb_ack_timer_timeout, p_ccb);
}
} else if ((fixed_queue_is_empty(p_ccb->xmit_hold_q) ||
l2c_fcr_is_flow_controlled(p_ccb)) &&
fixed_queue_is_empty(p_ccb->fcrb.srej_rcv_hold_q)) {
l2c_fcr_send_S_frame(p_ccb, L2CAP_FCR_SUP_RR, 0);
}
}
}
/*******************************************************************************
*
* Function do_sar_reassembly
*
* Description Process SAR bits and re-assemble frame
*
* Returns true if all OK, else false
*
******************************************************************************/
static bool do_sar_reassembly(tL2C_CCB* p_ccb, BT_HDR* p_buf,
uint16_t ctrl_word) {
CHECK(p_ccb != NULL);
CHECK(p_buf != NULL);
tL2C_FCRB* p_fcrb = &p_ccb->fcrb;
uint16_t sar_type = ctrl_word & L2CAP_FCR_SEG_BITS;
bool packet_ok = true;
uint8_t* p;
/* Check if the SAR state is correct */
if ((sar_type == L2CAP_FCR_UNSEG_SDU) || (sar_type == L2CAP_FCR_START_SDU)) {
if (p_fcrb->p_rx_sdu != NULL) {
log::warn(
"SAR - got unexpected unsegmented or start SDU Expected len: {} "
"Got so far: {}",
p_fcrb->rx_sdu_len, p_fcrb->p_rx_sdu->len);
packet_ok = false;
}
/* Check the length of the packet */
if ((sar_type == L2CAP_FCR_START_SDU) &&
(p_buf->len < L2CAP_SDU_LEN_OVERHEAD)) {
log::warn("SAR start packet too short: {}", p_buf->len);
packet_ok = false;
}
} else {
if (p_fcrb->p_rx_sdu == NULL) {
log::warn("SAR - got unexpected cont or end SDU");
packet_ok = false;
}
}
if ((packet_ok) && (sar_type != L2CAP_FCR_UNSEG_SDU)) {
p = ((uint8_t*)(p_buf + 1)) + p_buf->offset;
/* For start SDU packet, extract the SDU length */
if (sar_type == L2CAP_FCR_START_SDU) {
/* Get the SDU length */
STREAM_TO_UINT16(p_fcrb->rx_sdu_len, p);
p_buf->offset += 2;
p_buf->len -= 2;
if (p_fcrb->rx_sdu_len > p_ccb->max_rx_mtu) {
log::warn("SAR - SDU len: {} larger than MTU: {}", p_fcrb->rx_sdu_len,
p_ccb->max_rx_mtu);
packet_ok = false;
} else {
p_fcrb->p_rx_sdu = (BT_HDR*)osi_malloc(
BT_HDR_SIZE + OBX_BUF_MIN_OFFSET + p_fcrb->rx_sdu_len);
p_fcrb->p_rx_sdu->offset = OBX_BUF_MIN_OFFSET;
p_fcrb->p_rx_sdu->len = 0;
}
}
if (packet_ok) {
if ((p_fcrb->p_rx_sdu->len + p_buf->len) > p_fcrb->rx_sdu_len) {
log::error("SAR - SDU len exceeded Type: {} Lengths: {} {} {}",
sar_type, p_fcrb->p_rx_sdu->len, p_buf->len,
p_fcrb->rx_sdu_len);
packet_ok = false;
} else if ((sar_type == L2CAP_FCR_END_SDU) &&
((p_fcrb->p_rx_sdu->len + p_buf->len) != p_fcrb->rx_sdu_len)) {
log::warn("SAR - SDU end rcvd but SDU incomplete: {} {} {}",
p_fcrb->p_rx_sdu->len, p_buf->len, p_fcrb->rx_sdu_len);
packet_ok = false;
} else {
memcpy(((uint8_t*)(p_fcrb->p_rx_sdu + 1)) + p_fcrb->p_rx_sdu->offset +
p_fcrb->p_rx_sdu->len,
p, p_buf->len);
p_fcrb->p_rx_sdu->len += p_buf->len;
osi_free(p_buf);
p_buf = NULL;
if (sar_type == L2CAP_FCR_END_SDU) {
p_buf = p_fcrb->p_rx_sdu;
p_fcrb->p_rx_sdu = NULL;
}
}
}
}
if (!packet_ok) {
osi_free(p_buf);
} else if (p_buf != NULL) {
if (p_ccb->local_cid < L2CAP_BASE_APPL_CID &&
(p_ccb->local_cid >= L2CAP_FIRST_FIXED_CHNL &&
p_ccb->local_cid <= L2CAP_LAST_FIXED_CHNL)) {
if (l2cb.fixed_reg[p_ccb->local_cid - L2CAP_FIRST_FIXED_CHNL]
.pL2CA_FixedData_Cb)
(*l2cb.fixed_reg[p_ccb->local_cid - L2CAP_FIRST_FIXED_CHNL]
.pL2CA_FixedData_Cb)(p_ccb->local_cid,
p_ccb->p_lcb->remote_bd_addr, p_buf);
} else
l2c_csm_execute(p_ccb, L2CEVT_L2CAP_DATA, p_buf);
}
return (packet_ok);
}
/*******************************************************************************
*
* Function retransmit_i_frames
*
* Description This function retransmits i-frames awaiting acks.
*
* Returns bool - true if retransmitted
*
******************************************************************************/
static bool retransmit_i_frames(tL2C_CCB* p_ccb, uint8_t tx_seq) {
CHECK(p_ccb != NULL);
BT_HDR* p_buf = NULL;
uint8_t* p;
uint8_t buf_seq;
uint16_t ctrl_word;
if ((!fixed_queue_is_empty(p_ccb->fcrb.waiting_for_ack_q)) &&
(p_ccb->peer_cfg.fcr.max_transmit != 0) &&
(p_ccb->fcrb.num_tries >= p_ccb->peer_cfg.fcr.max_transmit)) {
log::verbose(
"Max Tries Exceeded: (last_acq: {} CID: 0x{:04x} num_tries: {} "
"(max: {}) ack_q_count: {}",
p_ccb->fcrb.last_rx_ack, p_ccb->local_cid, p_ccb->fcrb.num_tries,
p_ccb->peer_cfg.fcr.max_transmit,
fixed_queue_length(p_ccb->fcrb.waiting_for_ack_q));
l2cu_disconnect_chnl(p_ccb);
return (false);
}
/* tx_seq indicates whether to retransmit a specific sequence or all (if ==
* L2C_FCR_RETX_ALL_PKTS) */
list_t* list_ack = NULL;
const list_node_t* node_ack = NULL;
if (!fixed_queue_is_empty(p_ccb->fcrb.waiting_for_ack_q)) {
list_ack = fixed_queue_get_list(p_ccb->fcrb.waiting_for_ack_q);
node_ack = list_begin(list_ack);
}
if (tx_seq != L2C_FCR_RETX_ALL_PKTS) {
/* If sending only one, the sequence number tells us which one. Look for it.
*/
if (list_ack != NULL) {
for (; node_ack != list_end(list_ack); node_ack = list_next(node_ack)) {
p_buf = (BT_HDR*)list_node(node_ack);
/* Get the old control word */
p = ((uint8_t*)(p_buf + 1)) + p_buf->offset + L2CAP_PKT_OVERHEAD;
STREAM_TO_UINT16(ctrl_word, p);
buf_seq =
(ctrl_word & L2CAP_FCR_TX_SEQ_BITS) >> L2CAP_FCR_TX_SEQ_BITS_SHIFT;
log::verbose("retransmit_i_frames() cur seq: {} looking for: {}",
buf_seq, tx_seq);
if (tx_seq == buf_seq) break;
}
}
if (!p_buf) {
log::error("retransmit_i_frames() UNKNOWN seq: {} q_count: {}", tx_seq,
fixed_queue_length(p_ccb->fcrb.waiting_for_ack_q));
return (true);
}
} else {
// Iterate though list and flush the amount requested from
// the transmit data queue that satisfy the layer and event conditions.
for (list_node_t* node_tmp = list_begin(p_ccb->p_lcb->link_xmit_data_q);
node_tmp != list_end(p_ccb->p_lcb->link_xmit_data_q);) {
BT_HDR* p_tmp = (BT_HDR*)list_node(node_tmp);
node_tmp = list_next(node_tmp);
/* Do not flush other CIDs or partial segments */
if ((p_tmp->layer_specific == 0) && (p_tmp->event == p_ccb->local_cid)) {
list_remove(p_ccb->p_lcb->link_xmit_data_q, p_tmp);
osi_free(p_tmp);
}
}
/* Also flush our retransmission queue */
while (!fixed_queue_is_empty(p_ccb->fcrb.retrans_q))
osi_free(fixed_queue_try_dequeue(p_ccb->fcrb.retrans_q));
if (list_ack != NULL) node_ack = list_begin(list_ack);
}
if (list_ack != NULL) {
while (node_ack != list_end(list_ack)) {
p_buf = (BT_HDR*)list_node(node_ack);
node_ack = list_next(node_ack);
BT_HDR* p_buf2 = l2c_fcr_clone_buf(p_buf, p_buf->offset, p_buf->len);
if (p_buf2) {
p_buf2->layer_specific = p_buf->layer_specific;
fixed_queue_enqueue(p_ccb->fcrb.retrans_q, p_buf2);
}
if ((tx_seq != L2C_FCR_RETX_ALL_PKTS) || (p_buf2 == NULL)) break;
}
}
l2c_link_check_send_pkts(p_ccb->p_lcb, 0, NULL);
if (fixed_queue_length(p_ccb->fcrb.waiting_for_ack_q)) {
p_ccb->fcrb.num_tries++;
l2c_fcr_start_timer(p_ccb);
}
return (true);
}
/*******************************************************************************
*
* Function l2c_fcr_get_next_xmit_sdu_seg
*
* Description Get the next SDU segment to transmit.
*
* Returns pointer to buffer with segment or NULL
*
******************************************************************************/
BT_HDR* l2c_fcr_get_next_xmit_sdu_seg(tL2C_CCB* p_ccb,
uint16_t max_packet_length) {
CHECK(p_ccb != NULL);
bool first_seg = false, /* The segment is the first part of data */
mid_seg = false, /* The segment is the middle part of data */
last_seg = false; /* The segment is the last part of data */
uint16_t sdu_len = 0;
BT_HDR *p_buf, *p_xmit;
uint8_t* p;
uint16_t max_pdu = p_ccb->tx_mps /* Needed? - L2CAP_MAX_HEADER_FCS*/;
/* If there is anything in the retransmit queue, that goes first
*/
p_buf = (BT_HDR*)fixed_queue_try_dequeue(p_ccb->fcrb.retrans_q);
if (p_buf != NULL) {
/* Update Rx Seq and FCS if we acked some packets while this one was queued
*/
prepare_I_frame(p_ccb, p_buf, true);
p_buf->event = p_ccb->local_cid;
return (p_buf);
}
/* For BD/EDR controller, max_packet_length is set to 0 */
/* For AMP controller, max_packet_length is set by available blocks */
if ((max_packet_length > L2CAP_MAX_HEADER_FCS) &&
(max_pdu + L2CAP_MAX_HEADER_FCS > max_packet_length)) {
max_pdu = max_packet_length - L2CAP_MAX_HEADER_FCS;
}
p_buf = (BT_HDR*)fixed_queue_try_peek_first(p_ccb->xmit_hold_q);
/* If there is more data than the MPS, it requires segmentation */
if (p_buf->len > max_pdu) {
/* We are using the "event" field to tell is if we already started
* segmentation */
if (p_buf->event == 0) {
first_seg = true;
sdu_len = p_buf->len;
} else
mid_seg = true;
/* Get a new buffer and copy the data that can be sent in a PDU */
p_xmit = l2c_fcr_clone_buf(p_buf, L2CAP_MIN_OFFSET + L2CAP_SDU_LEN_OFFSET,
max_pdu);
if (p_xmit != NULL) {
p_buf->event = p_ccb->local_cid;
p_xmit->event = p_ccb->local_cid;
p_buf->len -= max_pdu;
p_buf->offset += max_pdu;
/* copy PBF setting */
p_xmit->layer_specific = p_buf->layer_specific;
} else /* Should never happen if the application has configured buffers
correctly */
{
log::error("L2CAP - cannot get buffer for segmentation, max_pdu: {}",
max_pdu);
return (NULL);
}
} else /* Use the original buffer if no segmentation, or the last segment */
{
p_xmit = (BT_HDR*)fixed_queue_try_dequeue(p_ccb->xmit_hold_q);
if (p_xmit->event != 0) last_seg = true;
p_xmit->event = p_ccb->local_cid;
}
/* Step back to add the L2CAP headers */
p_xmit->offset -= (L2CAP_PKT_OVERHEAD + L2CAP_FCR_OVERHEAD);
p_xmit->len += L2CAP_PKT_OVERHEAD + L2CAP_FCR_OVERHEAD;
if (first_seg) {
p_xmit->offset -= L2CAP_SDU_LEN_OVERHEAD;
p_xmit->len += L2CAP_SDU_LEN_OVERHEAD;
}
/* Set the pointer to the beginning of the data */
p = (uint8_t*)(p_xmit + 1) + p_xmit->offset;
/* Now the L2CAP header */
/* Note: if FCS has to be included then the length is recalculated later */
UINT16_TO_STREAM(p, p_xmit->len - L2CAP_PKT_OVERHEAD);
UINT16_TO_STREAM(p, p_ccb->remote_cid);
if (first_seg) {
/* Skip control word and add SDU length */
p += 2;
UINT16_TO_STREAM(p, sdu_len);
/* We will store the SAR type in layer-specific */
/* layer_specific is shared with flushable flag(bits 0-1), don't clear it */
p_xmit->layer_specific |= L2CAP_FCR_START_SDU;
first_seg = false;
} else if (mid_seg)
p_xmit->layer_specific |= L2CAP_FCR_CONT_SDU;
else if (last_seg)
p_xmit->layer_specific |= L2CAP_FCR_END_SDU;
else
p_xmit->layer_specific |= L2CAP_FCR_UNSEG_SDU;
prepare_I_frame(p_ccb, p_xmit, false);
if (p_ccb->peer_cfg.fcr.mode == L2CAP_FCR_ERTM_MODE) {
BT_HDR* p_wack =
l2c_fcr_clone_buf(p_xmit, HCI_DATA_PREAMBLE_SIZE, p_xmit->len);
if (!p_wack) {
log::error(
"L2CAP - no buffer for xmit cloning, CID: 0x{:04x} Length: {}",
p_ccb->local_cid, p_xmit->len);
/* We will not save the FCS in case we reconfigure and change options */
p_xmit->len -= L2CAP_FCS_LEN;
/* Pretend we sent it and it got lost */
fixed_queue_enqueue(p_ccb->fcrb.waiting_for_ack_q, p_xmit);
return (NULL);
} else {
/* We will not save the FCS in case we reconfigure and change options */
p_wack->len -= L2CAP_FCS_LEN;
p_wack->layer_specific = p_xmit->layer_specific;
fixed_queue_enqueue(p_ccb->fcrb.waiting_for_ack_q, p_wack);
}
}
return (p_xmit);
}
/** Get the next PDU to transmit for LE connection oriented channel. Returns
* pointer to buffer with PDU. |last_piece_of_sdu| will be set to true, if
* returned PDU is last piece from this SDU.*/
BT_HDR* l2c_lcc_get_next_xmit_sdu_seg(tL2C_CCB* p_ccb,
bool* last_piece_of_sdu) {
uint16_t max_pdu = p_ccb->peer_conn_cfg.mps - 4 /* Length and CID */;
BT_HDR* p_buf = (BT_HDR*)fixed_queue_try_peek_first(p_ccb->xmit_hold_q);
bool first_pdu = (p_buf->event == 0) ? true : false;
uint16_t no_of_bytes_to_send = std::min(
p_buf->len,
(uint16_t)(first_pdu ? (max_pdu - L2CAP_LCC_SDU_LENGTH) : max_pdu));
bool last_pdu = (no_of_bytes_to_send == p_buf->len);
/* Get a new buffer and copy the data that can be sent in a PDU */
BT_HDR* p_xmit =
l2c_fcr_clone_buf(p_buf, first_pdu ? L2CAP_LCC_OFFSET : L2CAP_MIN_OFFSET,
no_of_bytes_to_send);
p_buf->event = p_ccb->local_cid;
p_xmit->event = p_ccb->local_cid;
if (first_pdu) {
p_xmit->offset -= L2CAP_LCC_SDU_LENGTH; /* for writing the SDU length. */
uint8_t* p = (uint8_t*)(p_xmit + 1) + p_xmit->offset;
UINT16_TO_STREAM(p, p_buf->len);
p_xmit->len += L2CAP_LCC_SDU_LENGTH;
}
p_buf->len -= no_of_bytes_to_send;
p_buf->offset += no_of_bytes_to_send;
/* copy PBF setting */
p_xmit->layer_specific = p_buf->layer_specific;
if (last_piece_of_sdu) *last_piece_of_sdu = last_pdu;
if (last_pdu) {
p_buf = (BT_HDR*)fixed_queue_try_dequeue(p_ccb->xmit_hold_q);
osi_free(p_buf);
}
/* Step back to add the L2CAP headers */
p_xmit->offset -= L2CAP_PKT_OVERHEAD;
p_xmit->len += L2CAP_PKT_OVERHEAD;
/* Set the pointer to the beginning of the data */
uint8_t* p = (uint8_t*)(p_xmit + 1) + p_xmit->offset;
/* Note: if FCS has to be included then the length is recalculated later */
UINT16_TO_STREAM(p, p_xmit->len - L2CAP_PKT_OVERHEAD);
UINT16_TO_STREAM(p, p_ccb->remote_cid);
return (p_xmit);
}
/*******************************************************************************
* Configuration negotiation functions
*
* The following functions are used in negotiating channel modes during
* configuration
******************************************************************************/
/*******************************************************************************
*
* Function l2c_fcr_chk_chan_modes
*
* Description Validates and adjusts if necessary, the FCR options
* based on remote EXT features.
*
* Note: This assumes peer EXT Features have been received.
* Basic mode is used if FCR Options have not been received
*
* Returns uint8_t - nonzero if can continue, '0' if no compatible
* channels
*
******************************************************************************/
uint8_t l2c_fcr_chk_chan_modes(tL2C_CCB* p_ccb) {
CHECK(p_ccb != NULL);
/* Remove nonbasic options that the peer does not support */
if (!(p_ccb->p_lcb->peer_ext_fea & L2CAP_EXTFEA_ENH_RETRANS) &&
p_ccb->p_rcb->ertm_info.preferred_mode == L2CAP_FCR_ERTM_MODE) {
log::warn("L2CAP - Peer does not support our desired channel types");
p_ccb->p_rcb->ertm_info.preferred_mode = 0;
return false;
}
return true;
}
/*******************************************************************************
*
* Function l2c_fcr_adj_monitor_retran_timeout
*
* Description Overrides monitor/retrans timer value based on controller
*
* Returns None
*
******************************************************************************/
void l2c_fcr_adj_monitor_retran_timeout(tL2C_CCB* p_ccb) {
CHECK(p_ccb != NULL);
/* adjust our monitor/retran timeout */
if (p_ccb->out_cfg_fcr_present) {
/*
** if we requestd ERTM or accepted ERTM
** We may accept ERTM even if we didn't request ERTM, in case of requesting
*STREAM
*/
if ((p_ccb->our_cfg.fcr.mode == L2CAP_FCR_ERTM_MODE) ||
(p_ccb->peer_cfg.fcr.mode == L2CAP_FCR_ERTM_MODE)) {
/* upper layer setting is ignored */
p_ccb->our_cfg.fcr.mon_tout = L2CAP_MIN_MONITOR_TOUT;
p_ccb->our_cfg.fcr.rtrans_tout = L2CAP_MIN_RETRANS_TOUT;
} else {
p_ccb->our_cfg.fcr.mon_tout = 0;
p_ccb->our_cfg.fcr.rtrans_tout = 0;
}
log::verbose(
"l2c_fcr_adj_monitor_retran_timeout: mon_tout:{}, rtrans_tout:{}",
p_ccb->our_cfg.fcr.mon_tout, p_ccb->our_cfg.fcr.rtrans_tout);
}
}
/*******************************************************************************
*
* Function l2c_fcr_adj_our_rsp_options
*
* Description Overrides any neccesary FCR options passed in from
* L2CA_ConfigRsp based on our FCR options.
* Only makes adjustments if channel is in ERTM mode.
*
* Returns None
*
******************************************************************************/
void l2c_fcr_adj_our_rsp_options(tL2C_CCB* p_ccb, tL2CAP_CFG_INFO* p_cfg) {
CHECK(p_ccb != NULL);
CHECK(p_cfg != NULL);
/* adjust our monitor/retran timeout */
l2c_fcr_adj_monitor_retran_timeout(p_ccb);
p_cfg->fcr_present = p_ccb->out_cfg_fcr_present;
if (p_cfg->fcr_present) {
/* Temporary - until a better algorithm is implemented */
/* If peer's tx_wnd_sz requires too many buffers for us to support, then
* adjust it. For now, respond with our own tx_wnd_sz. */
/* Note: peer is not guaranteed to obey our adjustment */
if (p_ccb->peer_cfg.fcr.tx_win_sz > p_ccb->our_cfg.fcr.tx_win_sz) {
log::verbose("adjusting requested tx_win_sz from {} to {}",
p_ccb->peer_cfg.fcr.tx_win_sz, p_ccb->our_cfg.fcr.tx_win_sz);
p_ccb->peer_cfg.fcr.tx_win_sz = p_ccb->our_cfg.fcr.tx_win_sz;
}
p_cfg->fcr.mode = p_ccb->peer_cfg.fcr.mode;
p_cfg->fcr.tx_win_sz = p_ccb->peer_cfg.fcr.tx_win_sz;
p_cfg->fcr.max_transmit = p_ccb->peer_cfg.fcr.max_transmit;
p_cfg->fcr.mps = p_ccb->peer_cfg.fcr.mps;
p_cfg->fcr.rtrans_tout = p_ccb->our_cfg.fcr.rtrans_tout;
p_cfg->fcr.mon_tout = p_ccb->our_cfg.fcr.mon_tout;
}
}
/*******************************************************************************
*
* Function l2c_fcr_renegotiate_chan
*
* Description Called upon unsuccessful peer response to config request.
* If the error is because of the channel mode, it will try
* to resend using another supported optional channel.
*
* Returns true if resent configuration, False if channel matches or
* cannot match.
*
******************************************************************************/
bool l2c_fcr_renegotiate_chan(tL2C_CCB* p_ccb, tL2CAP_CFG_INFO* p_cfg) {
CHECK(p_ccb != NULL);
CHECK(p_cfg != NULL);
uint8_t peer_mode = p_ccb->our_cfg.fcr.mode;
bool can_renegotiate;
/* Skip if this is a reconfiguration from OPEN STATE or if FCR is not returned
*/
if (!p_cfg->fcr_present || (p_ccb->config_done & RECONFIG_FLAG))
return (false);
/* Only retry if there are more channel options to try */
if (p_cfg->result == L2CAP_CFG_UNACCEPTABLE_PARAMS) {
peer_mode = (p_cfg->fcr_present) ? p_cfg->fcr.mode : L2CAP_FCR_BASIC_MODE;
if (p_ccb->our_cfg.fcr.mode != peer_mode) {
if ((--p_ccb->fcr_cfg_tries) == 0) {
p_cfg->result = L2CAP_CFG_FAILED_NO_REASON;
log::warn("l2c_fcr_renegotiate_chan (Max retries exceeded)");
}
can_renegotiate = false;
/* Try another supported mode if available based on our last attempted
* channel */
switch (p_ccb->our_cfg.fcr.mode) {
case L2CAP_FCR_ERTM_MODE:
/* We can try basic for any other peer mode because it's always
* supported */
log::verbose("(Trying Basic)");
can_renegotiate = true;
p_ccb->our_cfg.fcr.mode = L2CAP_FCR_BASIC_MODE;
break;
default:
/* All other scenarios cannot be renegotiated */
break;
}
if (can_renegotiate) {
p_ccb->our_cfg.fcr_present = true;
if (p_ccb->our_cfg.fcr.mode == L2CAP_FCR_BASIC_MODE) {
p_ccb->our_cfg.fcs_present = false;
p_ccb->our_cfg.ext_flow_spec_present = false;
/* Basic Mode uses ACL Data Pool, make sure the MTU fits */
if ((p_cfg->mtu_present) && (p_cfg->mtu > L2CAP_MTU_SIZE)) {
log::warn("L2CAP - adjust MTU: {} too large", p_cfg->mtu);
p_cfg->mtu = L2CAP_MTU_SIZE;
}
}
l2cu_process_our_cfg_req(p_ccb, &p_ccb->our_cfg);
l2cu_send_peer_config_req(p_ccb, &p_ccb->our_cfg);
alarm_set_on_mloop(p_ccb->l2c_ccb_timer, L2CAP_CHNL_CFG_TIMEOUT_MS,
l2c_ccb_timer_timeout, p_ccb);
return (true);
}
}
}
/* Disconnect if the channels do not match */
if (p_ccb->our_cfg.fcr.mode != peer_mode) {
log::warn("L2C CFG: Channels incompatible (local {}, peer {})",
p_ccb->our_cfg.fcr.mode, peer_mode);
l2cu_disconnect_chnl(p_ccb);
}
return (false);
}
/*******************************************************************************
*
* Function l2c_fcr_process_peer_cfg_req
*
* Description This function is called to process the FCR options passed
* in the peer's configuration request.
*
* Returns uint8_t - L2CAP_PEER_CFG_OK, L2CAP_PEER_CFG_UNACCEPTABLE,
* or L2CAP_PEER_CFG_DISCONNECT.
*
******************************************************************************/
uint8_t l2c_fcr_process_peer_cfg_req(tL2C_CCB* p_ccb, tL2CAP_CFG_INFO* p_cfg) {
CHECK(p_ccb != NULL);
CHECK(p_cfg != NULL);
uint16_t max_retrans_size;
uint8_t fcr_ok = L2CAP_PEER_CFG_OK;
p_ccb->p_lcb->w4_info_rsp =
false; /* Handles T61x SonyEricsson Bug in Info Request */
log::verbose(
"l2c_fcr_process_peer_cfg_req() CFG fcr_present:{} fcr.mode:{} CCB FCR "
"mode:{} preferred: {}",
p_cfg->fcr_present, p_cfg->fcr.mode, p_ccb->our_cfg.fcr.mode,
p_ccb->p_rcb->ertm_info.preferred_mode);
/* Need to negotiate if our modes are not the same */
if (p_cfg->fcr.mode != p_ccb->p_rcb->ertm_info.preferred_mode) {
/* If peer wants a mode that we don't support then retry our mode (ex.
*rtx/flc), OR
** If we want ERTM and they want non-basic mode, retry our mode.
** Note: If we have already determined they support our mode previously
** from their EXF mask.
*/
if ((((1 << p_cfg->fcr.mode) & L2CAP_FCR_CHAN_OPT_ALL_MASK) == 0) ||
((p_ccb->p_rcb->ertm_info.preferred_mode == L2CAP_FCR_ERTM_MODE) &&
(p_cfg->fcr.mode != L2CAP_FCR_BASIC_MODE))) {
p_cfg->fcr.mode = p_ccb->our_cfg.fcr.mode;
p_cfg->fcr.tx_win_sz = p_ccb->our_cfg.fcr.tx_win_sz;
p_cfg->fcr.max_transmit = p_ccb->our_cfg.fcr.max_transmit;
fcr_ok = L2CAP_PEER_CFG_UNACCEPTABLE;
}
/* If we wanted basic, then try to renegotiate it */
else if (p_ccb->p_rcb->ertm_info.preferred_mode == L2CAP_FCR_BASIC_MODE) {
p_cfg->fcr.mode = L2CAP_FCR_BASIC_MODE;
p_cfg->fcr.max_transmit = p_cfg->fcr.tx_win_sz = 0;
p_cfg->fcr.rtrans_tout = p_cfg->fcr.mon_tout = p_cfg->fcr.mps = 0;
p_ccb->our_cfg.fcr.rtrans_tout = p_ccb->our_cfg.fcr.mon_tout =
p_ccb->our_cfg.fcr.mps = 0;
fcr_ok = L2CAP_PEER_CFG_UNACCEPTABLE;
}
}
/* Configuration for FCR channels so make any adjustments and fwd to upper
* layer */
if (fcr_ok == L2CAP_PEER_CFG_OK) {
/* by default don't need to send params in the response */
p_ccb->out_cfg_fcr_present = false;
/* Make any needed adjustments for the response to the peer */
if (p_cfg->fcr_present && p_cfg->fcr.mode != L2CAP_FCR_BASIC_MODE) {
/* Peer desires to bypass FCS check, and streaming or ERTM mode */
if (p_cfg->fcs_present) {
p_ccb->peer_cfg.fcs = p_cfg->fcs;
}
max_retrans_size = BT_DEFAULT_BUFFER_SIZE - sizeof(BT_HDR) -
L2CAP_MIN_OFFSET - L2CAP_SDU_LEN_OFFSET -
L2CAP_FCS_LEN;
/* Ensure the MPS is not bigger than the MTU */
if ((p_cfg->fcr.mps == 0) || (p_cfg->fcr.mps > p_ccb->peer_cfg.mtu)) {
p_cfg->fcr.mps = p_ccb->peer_cfg.mtu;
p_ccb->out_cfg_fcr_present = true;
}
/* Ensure the MPS is not bigger than our retransmission buffer */
if (p_cfg->fcr.mps > max_retrans_size) {
log::verbose("CFG: Overriding MPS to {} (orig {})", max_retrans_size,
p_cfg->fcr.mps);
p_cfg->fcr.mps = max_retrans_size;
p_ccb->out_cfg_fcr_present = true;
}
if (p_cfg->fcr.mode == L2CAP_FCR_ERTM_MODE) {
/* Always respond with FCR ERTM parameters */
p_ccb->out_cfg_fcr_present = true;
}
}
/* Everything ok, so save the peer's adjusted fcr options */
p_ccb->peer_cfg.fcr = p_cfg->fcr;
} else if (fcr_ok == L2CAP_PEER_CFG_UNACCEPTABLE) {
/* Allow peer only one retry for mode */
if (p_ccb->peer_cfg_already_rejected)
fcr_ok = L2CAP_PEER_CFG_DISCONNECT;
else
p_ccb->peer_cfg_already_rejected = true;
}
return (fcr_ok);
}