/**
* Checks if incoming PDU has a sequence number in accordance with the RX window
* @return 1 if SN is okay, 0 otherwise
* XXX Reordering window should also be handled here
*/
BOOL pdcp_is_rx_seq_number_valid(u16 seq_num, pdcp_t* pdcp_entity)
{
if (pdcp_is_seq_num_size_valid(pdcp_entity) == FALSE || pdcp_is_seq_num_valid(seq_num, pdcp_entity->seq_num_size) == FALSE)
return FALSE;
/*
* XXX Since we do not implement reordering window yet we expect to receive
* exactly the next SN from lower layer. When reordering window is implemented
* the operator utilized here should be >= as stated in 5.1.2.1.2
*/
if (seq_num == pdcp_entity->next_pdcp_rx_sn) {
// Incoming sequence number is in accordance with the RX window so
// update PDCP status for next expected RX sequence number
msg("[PDCP] Next expected SN arrived, advancing RX window\n");
return pdcp_advance_rx_window(pdcp_entity);
} else {
// XXX This is an error just because we don't have a reordering window!
msg("[PDCP] D'oh! Incoming SN is not the one we expected to receive! (Incoming:%d, Expected:%d)\n", \
seq_num, pdcp_entity->next_pdcp_rx_sn);
return FALSE;
}
}
/**
* Checks if incoming PDU has a sequence number in accordance with the RX window
* @return 1 if SN is okay, 0 otherwise
* XXX Reordering window should also be handled here
*/
boolean_t pdcp_is_rx_seq_number_valid(uint16_t seq_num, pdcp_t* pdcp_entity,srb_flag_t srb_flagP)
{
uint16_t reordering_window = 0;
#if 0
LOG_D(PDCP, "Incoming RX Sequence number is %04d\n", seq_num);
#endif
if (pdcp_is_seq_num_size_valid(pdcp_entity) == FALSE || pdcp_is_seq_num_valid(seq_num, pdcp_entity->seq_num_size) == FALSE) {
return FALSE;
}
/*
* Mark received sequence numbers to keep track of missing ones
* (and to build PDCP Control PDU for PDCP status report)
*/
if (pdcp_mark_current_pdu_as_received(seq_num, pdcp_entity) == TRUE) {
#if 0
LOG_I(PDCP, "Received sequence number successfuly marked\n");
#endif
} else {
LOG_W(PDCP, "Cannot mark received sequence number on the bitmap!\n");
}
/*
* RX Procedures for SRB and DRBs as described in sec 5.1.2 of 36.323
*/
if (srb_flagP) { // SRB
if (seq_num < pdcp_entity->next_pdcp_rx_sn) {
// decipher and verify the integrity of the PDU (if applicable) using COUNT based on RX_HFN + 1 and the received PDCP SN
pdcp_entity->rx_hfn++;
pdcp_entity->rx_hfn_offset = 0;
} else {
// decipher and verify the integrity of the PDU (if applicable) using COUNT based using COUNT based on RX_HFN and the received PDCP SN
pdcp_entity->rx_hfn_offset = 0;
}
// Assume that integrity verification is applicable and the integrity verification is passed successfully;
// or assume that integrity verification is not applicable:
// same the old next_pdcp_rx_sn to revert otherwise
pdcp_entity->next_pdcp_rx_sn_before_integrity = pdcp_entity->next_pdcp_rx_sn;
#if 0
if (seq_num != pdcp_entity->next_pdcp_rx_sn) {
LOG_D(PDCP,"Re-adjusting the sequence number to %d\n", seq_num);
}
#endif
//set Next_PDCP_RX_SN to the received PDCP SN +1 ;
pdcp_entity->next_pdcp_rx_sn = seq_num;
pdcp_advance_rx_window(pdcp_entity); // + 1, and check if it is larger than Maximum_PDCP_SN:
} else { // DRB
if (pdcp_entity->seq_num_size == PDCP_SN_7BIT) {
reordering_window = REORDERING_WINDOW_SN_7BIT;
} else {
reordering_window = REORDERING_WINDOW_SN_12BIT;
}
switch (pdcp_entity->rlc_mode) {
case RLC_MODE_AM:
if ((seq_num - pdcp_entity->last_submitted_pdcp_rx_sn > reordering_window) ||
((0 <= pdcp_entity->last_submitted_pdcp_rx_sn - seq_num) &&
(pdcp_entity->last_submitted_pdcp_rx_sn - seq_num < reordering_window) )) {
if (seq_num > pdcp_entity->next_pdcp_rx_sn) {
/*
* decipher the PDCP PDU as specified in the subclause 5.6, using COUNT based on RX_HFN - 1 and the received PDCP SN;
*/
pdcp_entity->rx_hfn_offset = -1;
} else {
/*
* decipher the PDCP PDU as specified in the subclause 5.6, using COUNT based on RX_HFN and the received PDCP SN;
*/
pdcp_entity->rx_hfn_offset = 0;
}
// discard this PDCP SDU;
LOG_W(PDCP, "Out of the reordering window (Incoming SN:%d, Expected SN:%d): discard this PDCP SDU\n",
seq_num, pdcp_entity->next_pdcp_rx_sn);
return FALSE;
} else if (pdcp_entity->next_pdcp_rx_sn - seq_num > reordering_window) {
pdcp_entity->rx_hfn++;
// use COUNT based on RX_HFN and the received PDCP SN for deciphering the PDCP PDU;
pdcp_entity->rx_hfn_offset = 0;
pdcp_entity->next_pdcp_rx_sn++;
} else if (seq_num - pdcp_entity->next_pdcp_rx_sn >= reordering_window ) {
// use COUNT based on RX_HFN – 1 and the received PDCP SN for deciphering the PDCP PDU;
pdcp_entity->rx_hfn_offset = -1;
} else if (seq_num >= pdcp_entity->next_pdcp_rx_sn ) {
// use COUNT based on RX_HFN and the received PDCP SN for deciphering the PDCP PDU;
pdcp_entity->rx_hfn_offset = 0;
//set Next_PDCP_RX_SN to the received PDCP SN +1 ;
pdcp_entity->next_pdcp_rx_sn = seq_num;
pdcp_advance_rx_window(pdcp_entity); // + 1, anc check if it is larger than Maximum_PDCP_SN:
#if 0
LOG_D(PDCP,"Re-adjusting the sequence number to %d\n", seq_num);
#endif
} else if (seq_num < pdcp_entity->next_pdcp_rx_sn) {
// use COUNT based on RX_HFN and the received PDCP SN for deciphering the PDCP PDU;
pdcp_entity->rx_hfn_offset = 0;
}
break;
case RLC_MODE_UM :
if (seq_num < pdcp_entity->next_pdcp_rx_sn) {
pdcp_entity->rx_hfn++;
}
// decipher the PDCP Data PDU using COUNT based on RX_HFN and the received PDCP SN as specified in the subclause 5.6;
//set Next_PDCP_RX_SN to the received PDCP SN +1 ;
pdcp_entity->next_pdcp_rx_sn = seq_num;
pdcp_advance_rx_window(pdcp_entity); // + 1, and check if it is larger than Maximum_PDCP_SN:
break;
case RLC_MODE_TM :
default:
LOG_W(PDCP,"RLC mode %d not supported\n",pdcp_entity->rlc_mode);
return FALSE;
}
}
/*
if (seq_num == pdcp_entity->next_pdcp_rx_sn) {
LOG_I(PDCP, "Next expected SN (%d) arrived, advancing RX window\n", seq_num);
return pdcp_advance_rx_window(pdcp_entity);
} else {
LOG_E(PDCP, "Incoming SN is not the one we expected to receive! (Incoming:%d, Expected:%d)\n", \
seq_num, pdcp_entity->next_pdcp_rx_sn);
// Update first missing PDU (used in PDCP Control PDU for PDCP status report, see 6.2.6)
if (pdcp_entity->first_missing_pdu != -1)
pdcp_entity->first_missing_pdu = pdcp_entity->next_pdcp_rx_sn;
return FALSE;
}
*/
return TRUE;
}
