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Commit fc691bc8 authored by Hansong Zhang's avatar Hansong Zhang
Browse files

Enforce remote MTU requirement in L2CAP directly 

AVCT_BR and BNEP don't need to enforce it locally.

Bug: 159815595
Tag: #refactor
Test: compile & verify basic functions working
Change-Id: I090d4e31b76e0098fc77e707ebd2eacf4cd78b7b
parent b5c07eeb

system/stack/avct/avct_l2c_br.cc

+1 −11
Original line number Diff line number Diff line
@@ -287,21 +287,11 @@ void avct_l2c_br_config_ind_cback(uint16_t lcid, tL2CAP_CFG_INFO* p_cfg) { 


  AVCT_TRACE_DEBUG("%s peer_mtu:%d use:%d", __func__, p_lcb->peer_mtu, max_mtu);



  if (p_lcb->peer_mtu >= AVCT_MIN_BROWSE_MTU)

  p_cfg->result = L2CAP_CFG_OK;

  else {

    p_cfg->result = L2CAP_CFG_UNACCEPTABLE_PARAMS;

    p_cfg->mtu_present = true;

    p_cfg->mtu = AVCT_MIN_BROWSE_MTU;

  }



  /* send L2CAP configure response */

  L2CA_ConfigRsp(lcid, p_cfg);



  if (p_cfg->result != L2CAP_CFG_OK) {

    return;

  }



  /* if first config ind */

  if ((p_lcb->ch_flags & AVCT_L2C_CFG_IND_DONE) == 0) {

    /* update flags */

system/stack/bnep/bnep_main.cc

+4 −21
Original line number Diff line number Diff line
@@ -205,7 +205,6 @@ static void bnep_connect_cfm(uint16_t l2cap_cid, uint16_t result) { 
 ******************************************************************************/

static void bnep_config_ind(uint16_t l2cap_cid, tL2CAP_CFG_INFO* p_cfg) {

  tBNEP_CONN* p_bcb;

  uint16_t result, mtu = 0;



  /* Find CCB based on CID */

  p_bcb = bnepu_find_bcb_by_cid(l2cap_cid);
@@ -217,29 +216,13 @@ static void bnep_config_ind(uint16_t l2cap_cid, tL2CAP_CFG_INFO* p_cfg) { 


  BNEP_TRACE_EVENT("BNEP - Rcvd cfg ind, CID: 0x%x", l2cap_cid);



  /* Remember the remote MTU size */

  if ((!p_cfg->mtu_present) || (p_cfg->mtu < BNEP_MTU_SIZE)) {

    mtu = p_cfg->mtu;

    p_cfg->flush_to_present = false;

    p_cfg->mtu_present = true;

    p_cfg->mtu = BNEP_MTU_SIZE;

    p_cfg->result = result = L2CAP_CFG_UNACCEPTABLE_PARAMS;

  } else {



  /* For now, always accept configuration from the other side */

  p_cfg->flush_to_present = false;

  p_cfg->mtu_present = false;

    p_cfg->result = result = L2CAP_CFG_OK;

  }

  p_cfg->result = L2CAP_CFG_OK;



  L2CA_ConfigRsp(l2cap_cid, p_cfg);



  if (result != L2CAP_CFG_OK) {

    BNEP_TRACE_EVENT("BNEP - Rcvd cfg ind with bad MTU %d, CID: 0x%x", mtu,

                     l2cap_cid);

    return;

  }



  p_bcb->con_flags |= BNEP_FLAGS_HIS_CFG_DONE;



  if (p_bcb->con_flags & BNEP_FLAGS_MY_CFG_DONE) {

system/stack/l2cap/l2c_utils.cc

+9 −4
Original line number Diff line number Diff line
@@ -1752,14 +1752,19 @@ uint8_t l2cu_process_peer_cfg_req(tL2C_CCB* p_ccb, tL2CAP_CFG_INFO* p_cfg) { 
  bool flush_to_ok = true;

  bool fcr_ok = true;

  uint8_t fcr_status;

  uint16_t required_remote_mtu =

      std::max<uint16_t>(L2CAP_MIN_MTU, p_ccb->p_rcb->required_remote_mtu);



  /* Ignore FCR parameters for basic mode */

  if (!p_cfg->fcr_present) p_cfg->fcr.mode = L2CAP_FCR_BASIC_MODE;



  /* Save the MTU that our peer can receive */

  if (p_cfg->mtu_present) {

  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;

    mtu_ok = false;

  } else if (p_cfg->mtu_present) {

    /* Make sure MTU is at least the minimum */

    if (p_cfg->mtu >= L2CAP_MIN_MTU) {

    if (p_cfg->mtu >= required_remote_mtu) {

      /* In basic mode, limit the MTU to our buffer size */

      if ((!p_cfg->fcr_present) && (p_cfg->mtu > L2CAP_MTU_SIZE))

        p_cfg->mtu = L2CAP_MTU_SIZE;
@@ -1769,7 +1774,7 @@ uint8_t l2cu_process_peer_cfg_req(tL2C_CCB* p_ccb, tL2CAP_CFG_INFO* p_cfg) { 
      p_ccb->peer_cfg.mtu_present = true;

    } else /* Illegal MTU value */

    {

      p_cfg->mtu = L2CAP_MIN_MTU;

      p_cfg->mtu = required_remote_mtu;

      mtu_ok = false;

    }

  }