/****************************************************************************** * * 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 #include #include #include "internal_include/bt_target.h" #include "osi/include/allocator.h" #include "stack/include/bt_hdr.h" #include "stack/include/bt_types.h" #include "stack/include/l2cdefs.h" #include "stack/l2cap/internal/l2c_api.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 uint16_t 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 uint16_t l2c_fcr_updcrc(uint16_t icrc, unsigned char* icp, int icnt) { uint16_t 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) { log::assert_that(p_ccb != NULL, "assert failed: 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) { log::assert_that(p_ccb != NULL, "assert failed: 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) { log::assert_that(p_ccb != NULL, "assert failed: 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) { log::assert_that(p_buf != NULL, "assert failed: 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) { log::assert_that(p_ccb != NULL, "assert failed: 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) { log::assert_that(p_ccb != NULL, "assert failed: p_ccb != NULL"); log::assert_that(p_buf != NULL, "assert failed: 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; uint8_t fcs_len = l2cu_get_fcs_len(p_ccb); 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 + fcs_len - L2CAP_PKT_OVERHEAD); if (fcs_len != 0) { /* 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 += 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) { log::assert_that(p_ccb != NULL, "assert failed: 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; uint8_t fcs_len = l2cu_get_fcs_len(p_ccb); /* Put in the L2CAP header */ 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 += 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) { log::assert_that(p_ccb != NULL, "assert failed: p_ccb != NULL"); log::assert_that(p_buf != NULL, "assert failed: p_buf != NULL"); uint8_t* p; uint16_t fcs; uint16_t min_pdu_len; uint16_t ctrl_word; /* Check the length */ 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); 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); if (fcs_len != 0) { /* Verify FCS if using */ 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 -= 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) { log::assert_that(p_ccb != NULL, "assert failed: p_ccb != NULL"); log::assert_that(p_buf != NULL, "assert failed: 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) { log::assert_that(p_ccb != NULL, "assert failed: 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) { log::assert_that(p_ccb != NULL, "assert failed: 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) { log::assert_that(p_ccb != NULL, "assert failed: 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) { log::assert_that(p_ccb != NULL, "assert failed: p_ccb != NULL"); log::assert_that(p_buf != NULL, "assert failed: 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 another 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) { log::assert_that(p_ccb != NULL, "assert failed: p_ccb != NULL"); log::assert_that(p_buf != NULL, "assert failed: 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 occurred */ 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) { log::assert_that(p_ccb != NULL, "assert failed: p_ccb != NULL"); log::assert_that(p_buf != NULL, "assert failed: 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) { l2cu_fixed_channel_data_cb(p_ccb->p_lcb, p_ccb->local_cid, 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) { log::assert_that(p_ccb != NULL, "assert failed: 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) { log::assert_that(p_ccb != NULL, "assert failed: 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); 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); 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 -= 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 -= 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) { log::assert_that(p_ccb != NULL, "assert failed: 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) { log::assert_that(p_ccb != NULL, "assert failed: 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) { log::assert_that(p_ccb != NULL, "assert failed: p_ccb != NULL"); log::assert_that(p_cfg != NULL, "assert failed: 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) { log::assert_that(p_ccb != NULL, "assert failed: p_ccb != NULL"); log::assert_that(p_cfg != NULL, "assert failed: 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 == tL2CAP_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 = tL2CAP_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) { log::assert_that(p_ccb != NULL, "assert failed: p_ccb != NULL"); log::assert_that(p_cfg != NULL, "assert failed: 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; } else if (p_ccb->p_rcb->ertm_info.preferred_mode == L2CAP_FCR_BASIC_MODE) { /* If we wanted basic, then try to renegotiate it */ 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; } } 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) { /* 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 - 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; }