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Commit bb69ca6c authored by Łukasz Rymanowski (xWF)'s avatar Łukasz Rymanowski (xWF) Committed by Gerrit Code Review
Browse files

Merge changes I62eeeb0e,I173ecff4,I5a233320 into main 

* changes:
  l2cap: Fix using FCS field in S/I frames
  l2cap: Store remote FCS Configuration options
  l2cap: Fix setting FCS Option
parents e81b586e 44d9c458

system/stack/l2cap/l2c_csm.cc

+8 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 


#include <base/functional/callback.h>

#include <bluetooth/log.h>

#include <com_android_bluetooth_flags.h>

#include <frameworks/proto_logging/stats/enums/bluetooth/enums.pb.h>



#include <string>
@@ -74,6 +75,13 @@ static void l2c_csm_send_config_req(tL2C_CCB* p_ccb) { 
  if (p_ccb->p_rcb->ertm_info.preferred_mode != L2CAP_FCR_BASIC_MODE) {

    config.fcr_present = true;

    config.fcr = kDefaultErtmOptions;



    if (com::android::bluetooth::flags::l2cap_fcs_option_fix()) {

      /* Later l2cu_process_our_cfg_req() will check if remote supports it, and if not, it will be

       * cleared as per spec. */

      config.fcs_present = true;

      config.fcs = 1;

    }

  }

  p_ccb->our_cfg = config;

  l2c_csm_execute(p_ccb, L2CEVT_L2CA_CONFIG_REQ, &config);

system/stack/l2cap/l2c_fcr.cc

+44 −29
Original line number Diff line number Diff line
@@ -280,6 +280,8 @@ static void prepare_I_frame(tL2C_CCB* p_ccb, BT_HDR* p_buf, bool is_retransmissi 
  uint16_t ctrl_word;

  bool set_f_bit = p_fcrb->send_f_rsp;



  uint8_t fcs_len = l2cu_get_fcs_len(p_ccb);



  p_fcrb->send_f_rsp = false;



  if (is_retransmission) {
@@ -317,8 +319,9 @@ static void prepare_I_frame(tL2C_CCB* p_ccb, BT_HDR* p_buf, bool is_retransmissi 
  /* 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);

  UINT16_TO_STREAM(p, p_buf->len + fcs_len - L2CAP_PKT_OVERHEAD);



  if (fcs_len != 0) {

    /* Calculate the FCS */

    fcs = l2c_fcr_tx_get_fcs(p_buf);
@@ -331,7 +334,8 @@ static void prepare_I_frame(tL2C_CCB* p_ccb, BT_HDR* p_buf, bool is_retransmissi 


    UINT16_TO_STREAM(p, fcs);



  p_buf->len += L2CAP_FCS_LEN;

    p_buf->len += fcs_len;

  }



  if (is_retransmission) {

    log::verbose(
@@ -397,16 +401,20 @@ void l2c_fcr_send_S_frame(tL2C_CCB* p_ccb, uint16_t function_code, uint16_t pf_b 
  /* Set the pointer to the beginning of the data */

  p = (uint8_t*)(p_buf + 1) + p_buf->offset;



  uint8_t fcs_len = l2cu_get_fcs_len(p_ccb);



  /* Put in the L2CAP header */

  UINT16_TO_STREAM(p, L2CAP_FCR_OVERHEAD + L2CAP_FCS_LEN);

  UINT16_TO_STREAM(p, L2CAP_FCR_OVERHEAD + fcs_len);

  UINT16_TO_STREAM(p, p_ccb->remote_cid);

  UINT16_TO_STREAM(p, ctrl_word);



  if (fcs_len != 0) {

    /* 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;

    p_buf->len += fcs_len;

  }



  /* Now, the HCI transport header */

  p_buf->layer_specific = L2CAP_NON_FLUSHABLE_PKT;
@@ -462,7 +470,9 @@ void l2c_fcr_proc_pdu(tL2C_CCB* p_ccb, BT_HDR* p_buf) { 
  uint16_t ctrl_word;



  /* Check the length */

  min_pdu_len = (uint16_t)(L2CAP_FCS_LEN + L2CAP_FCR_OVERHEAD);

  uint8_t fcs_len = l2cu_get_fcs_len(p_ccb);



  min_pdu_len = (uint16_t)(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);
@@ -514,18 +524,20 @@ void l2c_fcr_proc_pdu(tL2C_CCB* p_ccb, BT_HDR* p_buf) { 
          p_ccb->fcrb.last_ack_sent, fixed_queue_length(p_ccb->fcrb.waiting_for_ack_q),

          p_ccb->fcrb.num_tries);



  if (fcs_len != 0) {

    /* Verify FCS if using */

  p = ((uint8_t*)(p_buf + 1)) + p_buf->offset + p_buf->len - L2CAP_FCS_LEN;

    p = ((uint8_t*)(p_buf + 1)) + p_buf->offset + p_buf->len - fcs_len;



    /* Extract and drop the FCS from the packet */

    STREAM_TO_UINT16(fcs, p);

  p_buf->len -= L2CAP_FCS_LEN;

    p_buf->len -= 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;
@@ -1466,6 +1478,7 @@ BT_HDR* l2c_fcr_get_next_xmit_sdu_seg(tL2C_CCB* p_ccb, uint16_t max_packet_lengt 
  }



  prepare_I_frame(p_ccb, p_xmit, false);

  uint8_t fcs_len = l2cu_get_fcs_len(p_ccb);



  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);
@@ -1475,14 +1488,14 @@ BT_HDR* l2c_fcr_get_next_xmit_sdu_seg(tL2C_CCB* p_ccb, uint16_t max_packet_lengt 
                 p_xmit->len);



      /* We will not save the FCS in case we reconfigure and change options */

      p_xmit->len -= L2CAP_FCS_LEN;

      p_xmit->len -= 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->len -= fcs_len;



      p_wack->layer_specific = p_xmit->layer_specific;

      fixed_queue_enqueue(p_ccb->fcrb.waiting_for_ack_q, p_wack);
@@ -1793,6 +1806,8 @@ uint8_t l2c_fcr_process_peer_cfg_req(tL2C_CCB* p_ccb, tL2CAP_CFG_INFO* p_cfg) { 
    }

  }



  uint8_t fcs_len = l2cu_get_fcs_len(p_ccb);



  /* Configuration for FCR channels so make any adjustments and fwd to upper

   * layer */

  if (fcr_ok == L2CAP_PEER_CFG_OK) {
@@ -1807,7 +1822,7 @@ uint8_t l2c_fcr_process_peer_cfg_req(tL2C_CCB* p_ccb, tL2CAP_CFG_INFO* p_cfg) { 
      }



      max_retrans_size = BT_DEFAULT_BUFFER_SIZE - sizeof(BT_HDR) - L2CAP_MIN_OFFSET -

                         L2CAP_SDU_LEN_OFFSET - L2CAP_FCS_LEN;

                         L2CAP_SDU_LEN_OFFSET - 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)) {

system/stack/l2cap/l2c_int.h

+1 −0
Original line number Diff line number Diff line
@@ -762,6 +762,7 @@ void l2cu_release_ble_rcb(tL2C_RCB* p_rcb); 
tL2C_RCB* l2cu_allocate_ble_rcb(uint16_t psm);

tL2C_RCB* l2cu_find_ble_rcb_by_psm(uint16_t psm);



uint8_t l2cu_get_fcs_len(tL2C_CCB* p_ccb);

uint8_t l2cu_process_peer_cfg_req(tL2C_CCB* p_ccb, tL2CAP_CFG_INFO* p_cfg);

void l2cu_process_peer_cfg_rsp(tL2C_CCB* p_ccb, tL2CAP_CFG_INFO* p_cfg);

void l2cu_process_our_cfg_req(tL2C_CCB* p_ccb, tL2CAP_CFG_INFO* p_cfg);

system/stack/l2cap/l2c_utils.cc

+29 −0
Original line number Diff line number Diff line
@@ -1849,6 +1849,30 @@ tL2C_RCB* l2cu_find_ble_rcb_by_psm(uint16_t psm) { 
  return NULL;

}



/*************************************************************************************

 *

 * Function         l2cu_get_fcs_len

 *

 * Description      This function is called to determine FCS len in S/I Frames.

 *

 *

 * Returns          0 or L2CAP_FCS_LEN: 0 is returned when both sides configure `No FCS`

 *

 **************************************************************************************/

uint8_t l2cu_get_fcs_len(tL2C_CCB* p_ccb) {

  log::verbose("our.fcs_present: {} our.fcs: {},  peer.fcs_present: {} peer.fcs: {}",

               p_ccb->our_cfg.fcs_present, p_ccb->our_cfg.fcs, p_ccb->peer_cfg.fcs_present,

               p_ccb->peer_cfg.fcs);



  if (com::android::bluetooth::flags::l2cap_fcs_option_fix() &&

      (p_ccb->peer_cfg.fcs_present && p_ccb->peer_cfg.fcs == 0x00) &&

      (p_ccb->our_cfg.fcs_present && p_ccb->our_cfg.fcs == 0x00)) {

    return 0;

  }



  return L2CAP_FCS_LEN;

}



/*******************************************************************************

 *

 * Function         l2cu_process_peer_cfg_req
@@ -1884,6 +1908,11 @@ uint8_t l2cu_process_peer_cfg_req(tL2C_CCB* p_ccb, tL2CAP_CFG_INFO* p_cfg) { 
    p_cfg->fcr.mode = L2CAP_FCR_BASIC_MODE;

  }



  if (com::android::bluetooth::flags::l2cap_fcs_option_fix() && p_cfg->fcs_present) {

    p_ccb->peer_cfg.fcs_present = 1;

    p_ccb->peer_cfg.fcs = p_cfg->fcs;

  }



  if (!p_cfg->mtu_present && required_remote_mtu > L2CAP_DEFAULT_MTU) {

    // We reject if we have a MTU requirement higher than default MTU

    p_cfg->mtu = required_remote_mtu;