Harald Welte | 060e27a | 2018-03-03 20:38:19 +0100 | [diff] [blame] | 1 | module GPRS_TBF { |
| 2 | |
| 3 | /* GPRS TBF Routines, intended as minimal MS-Side GPRS implementation |
| 4 | * |
| 5 | * (C) 2018 by Harald Welte <laforge@gnumonks.org> |
| 6 | * All rights reserved. |
| 7 | * |
| 8 | * Released under the terms of GNU General Public License, Version 2 or |
| 9 | * (at your option) any later version. |
| 10 | */ |
| 11 | |
| 12 | |
| 13 | import from GSM_Types all; |
| 14 | import from Osmocom_Types all; |
| 15 | import from General_Types all; |
| 16 | import from RLCMAC_Types all; |
| 17 | import from RLCMAC_CSN1_Types all; |
| 18 | import from LLC_Types all; |
| 19 | import from GPRS_Context all; |
| 20 | |
Harald Welte | cc5c115 | 2018-03-09 12:54:01 +0100 | [diff] [blame] | 21 | private const integer RLC_GPRS_SNS := 128; |
| 22 | private const integer RLC_GPRS_WS := 64; |
| 23 | private const integer RLC_EGPRS_MIN_WS := 64; |
| 24 | private const integer RLC_EGPRS_MAX_WS := 1024; |
| 25 | private const integer RLC_EGPRS_SNS := 2048; |
| 26 | private const integer RLC_EGPRS_MAX_BSN_DELTA := 512; |
| 27 | private const integer RLC_MAX_SNS := RLC_EGPRS_SNS; |
| 28 | private const integer RLC_MAX_WS := RLC_EGPRS_MAX_WS; |
| 29 | private const integer RLC_MAX_LEN := 74 /* MCS-9 data unit */ |
Harald Welte | 060e27a | 2018-03-03 20:38:19 +0100 | [diff] [blame] | 30 | |
Harald Welte | cc5c115 | 2018-03-09 12:54:01 +0100 | [diff] [blame] | 31 | private const integer sns_half := (RLC_MAX_SNS / 2); |
| 32 | private const integer mod_sns_half := (RLC_MAX_SNS / 2) - 1; |
| 33 | |
| 34 | |
| 35 | /*********************************************************************** |
| 36 | * Uplink TBF handling |
| 37 | ***********************************************************************/ |
| 38 | |
| 39 | /* input parameters into TBF (mostly mode/cs + LLC PDUs */ |
Harald Welte | 060e27a | 2018-03-03 20:38:19 +0100 | [diff] [blame] | 40 | type record UlTbfPars { |
| 41 | /* Acknowledged mode (true) or unacknowledged (false) */ |
| 42 | boolean ack_mode, |
| 43 | /* Coding Scheme for transmission, determines block size */ |
| 44 | GprsCodingScheme initial_cs, |
| 45 | /* list of abstract/decoded LLC PDUs */ |
| 46 | record of PDU_LLC llc_pdus optional, |
| 47 | /* possibly computed: list of encoded LLC PDUs */ |
| 48 | record of octetstring llc_pdus_enc |
| 49 | } |
| 50 | |
| 51 | type record RlcEndpointTx { |
| 52 | /* send state variable V(S) (9.1.1): 0 .. SNS-1 */ |
| 53 | integer v_s, |
| 54 | /* acknowledge state variable V(A) (9.1.2): BSN value of oldest RLC data block that has not |
| 55 | * been positively acknowledged by peer. */ |
| 56 | integer v_a, |
| 57 | /* acknowledge state array V(B) (9.1.3) */ |
| 58 | bitstring v_b |
| 59 | } |
| 60 | private function f_RlcEndpointTx_init(inout RlcEndpointTx ep) { |
| 61 | ep.v_s := 0; |
| 62 | ep.v_a := 0; |
| 63 | ep.v_b := int2bit(0, 128); /* FIXME: EGPRS 2048 bits length */ |
| 64 | } |
| 65 | |
Harald Welte | 060e27a | 2018-03-03 20:38:19 +0100 | [diff] [blame] | 66 | type record UlTbfState { |
| 67 | /* "const" input state with TBF Data */ |
| 68 | UlTbfPars tbf, |
| 69 | uint8_t num_ts, |
| 70 | |
| 71 | RlcEndpointTx et, |
| 72 | |
| 73 | integer tfi, |
| 74 | /* total length of all encoded LLC PDUs */ |
| 75 | integer llc_pdu_totlen, |
| 76 | /* index of current/next PDU in llc_pdus_enc */ |
| 77 | integer cur_pdu, |
| 78 | /* byte offset into current/next PDU; next byte to transmit */ |
| 79 | integer cur_index, |
| 80 | /* block sequence number of next block within TBF */ |
| 81 | integer bsn_p, |
| 82 | /* total number of bytes remaining in TBF */ |
| 83 | integer total_bytes_remain, |
| 84 | |
| 85 | /* list of already-sent RLC/MAC Blocks */ |
| 86 | record of RlcmacUlBlock rlc_sent |
| 87 | } |
| 88 | |
| 89 | function f_UlTbfState_init(inout UlTbfState us, in UlTbfPars utpars) { |
| 90 | var RlcmacUlBlock blk; |
| 91 | |
| 92 | us.tbf := utpars; |
| 93 | us.num_ts := 1; |
| 94 | |
| 95 | f_RlcEndpointTx_init(us.et); |
| 96 | |
| 97 | us.tfi := 0; /* FIXME */ |
| 98 | us.cur_pdu := 0; |
| 99 | us.cur_index := 0; |
| 100 | us.bsn_p := 0; |
| 101 | us.total_bytes_remain := 0; |
| 102 | us.rlc_sent := {}; |
| 103 | |
| 104 | /* encode all LLC PDUs from their abstract type to octetstring */ |
| 105 | us.cur_pdu := 0; /* currently processed PDU */ |
| 106 | us.cur_index := 0; /* next to-be transmitted index */ |
| 107 | if (ispresent(us.tbf.llc_pdus)) { |
| 108 | us.tbf.llc_pdus_enc := {}; |
| 109 | us.llc_pdu_totlen := 0; |
| 110 | for (var integer i := 0; i < sizeof(us.tbf.llc_pdus); i := i+1) { |
| 111 | var octetstring cur_enc := enc_PDU_LLC(us.tbf.llc_pdus[i]); |
| 112 | us.tbf.llc_pdus_enc := us.tbf.llc_pdus_enc & { cur_enc }; |
| 113 | us.llc_pdu_totlen := us.llc_pdu_totlen + lengthof(cur_enc); |
| 114 | } |
| 115 | us.total_bytes_remain := us.llc_pdu_totlen; |
| 116 | } |
| 117 | } |
| 118 | |
| 119 | private function f_UlTbf_ack_one_block(inout UlTbfState us, integer n) { |
| 120 | /* compute index into v_b */ |
| 121 | var integer idx := n - us.et.v_a; |
| 122 | if (idx < 0 or idx > lengthof(us.et.v_b)) { |
| 123 | setverdict(fail, "UlTbf: Cannot ACK ", n, " while V(A) is ", us.et.v_a); |
Daniel Willmann | afce866 | 2018-07-06 23:11:32 +0200 | [diff] [blame] | 124 | mtc.stop; |
Harald Welte | 060e27a | 2018-03-03 20:38:19 +0100 | [diff] [blame] | 125 | } |
| 126 | /* set the bit in the acknowledge state array */ |
| 127 | us.et.v_b[idx] := '1'B; |
| 128 | } |
| 129 | |
| 130 | /* check if V(B) contains '1' at lower end: if yes, advance V(A) and shift V(B) */ |
| 131 | private function f_UlTbf_check_advance_v_a(inout UlTbfState us) { |
| 132 | log("FIXME: Implement this"); |
| 133 | } |
| 134 | |
| 135 | /* copy 'len' number of bytes from current pending LLC PDU */ |
| 136 | private function f_copy_from_llc(inout UlTbfState us, integer len) return octetstring |
| 137 | { |
| 138 | var integer pdu_len := lengthof(us.tbf.llc_pdus_enc[us.cur_pdu]) |
| 139 | var octetstring ret; |
| 140 | |
| 141 | ret := substr(us.tbf.llc_pdus_enc[us.cur_pdu], us.cur_index, len); |
| 142 | |
| 143 | us.cur_index := us.cur_index + len; |
| 144 | us.total_bytes_remain := us.total_bytes_remain - len; |
| 145 | |
| 146 | log("copy_from_llc: ", ret, " us: ", us); |
| 147 | |
| 148 | /* if we completed this PDU, move on to the next, resetting the index */ |
| 149 | if (us.cur_index >= pdu_len) { |
| 150 | us.cur_pdu := us.cur_pdu +1; |
| 151 | us.cur_index := 0; |
| 152 | log("copy_from_llc (incrementing pdu)"); |
| 153 | } |
| 154 | |
| 155 | return ret; |
| 156 | } |
| 157 | |
| 158 | /* generate one LlcBlock (maximum size 'max_len') */ |
| 159 | private function f_ul_tbf_pull_one(out LlcBlock ret, inout LlcBlockHdr prev_hdr, |
| 160 | inout UlTbfState us, integer max_len, |
| 161 | boolean is_final) return boolean |
| 162 | { |
| 163 | /* if we've already pulled all data from all LLC PDUs: nothing to do */ |
| 164 | if (us.cur_pdu >= sizeof(us.tbf.llc_pdus_enc)) { |
| 165 | log("pull_one: No more data", us); |
| 166 | return false; |
| 167 | } |
| 168 | |
| 169 | var integer pdu_len := lengthof(us.tbf.llc_pdus_enc[us.cur_pdu]) |
| 170 | var integer cur_llc_remain_len := pdu_len - us.cur_index; |
| 171 | var integer len; |
| 172 | var LlcBlock lb; |
| 173 | |
| 174 | if (us.cur_index == 0) { |
| 175 | /* start of a new LLC PDU */ |
| 176 | prev_hdr.more := true; |
| 177 | } |
| 178 | |
| 179 | if (cur_llc_remain_len > max_len) { |
| 180 | log("Chunk with length ", cur_llc_remain_len, " larger than space (", |
| 181 | max_len, ") left in block"); |
| 182 | len := max_len; |
| 183 | lb := { |
| 184 | hdr := omit, |
| 185 | payload := f_copy_from_llc(us, len) |
| 186 | } |
| 187 | } else if (cur_llc_remain_len == max_len and is_final) { |
| 188 | /* final RLC block of TBF and LLC remainder fits exactly */ |
| 189 | len := max_len; |
| 190 | lb := { |
| 191 | hdr := omit, |
| 192 | payload := f_copy_from_llc(us, len) |
| 193 | } |
| 194 | prev_hdr.e := true; |
| 195 | } else if (cur_llc_remain_len == max_len) { |
| 196 | /* LLC remaineder would fit exactly -> "singular case" with L=0 */ |
| 197 | len := max_len - 1; |
| 198 | lb := { |
| 199 | hdr := { |
| 200 | length_ind := 0, |
| 201 | more := false, |
| 202 | e := true |
| 203 | }, |
| 204 | payload := f_copy_from_llc(us, len) |
| 205 | } |
| 206 | prev_hdr.e := false; |
| 207 | } else { |
| 208 | /* normal case: cur_llc_remain_len < max_len */ |
| 209 | len := cur_llc_remain_len; |
| 210 | lb := { |
| 211 | hdr := { |
| 212 | length_ind := len, |
| 213 | more := false, |
| 214 | e := true |
| 215 | }, |
| 216 | payload := f_copy_from_llc(us, len) |
| 217 | } |
| 218 | prev_hdr.e := false; |
| 219 | } |
| 220 | ret := lb; |
| 221 | return true; |
| 222 | } |
| 223 | |
| 224 | /* return encoded size of one given LlcBlock */ |
| 225 | private function f_LlcBlock_enc_len(LlcBlock blk) return integer { |
| 226 | if (isvalue(blk.hdr)) { |
| 227 | return 1 + lengthof(blk.payload); |
| 228 | } else { |
| 229 | return lengthof(blk.payload); |
| 230 | } |
| 231 | } |
| 232 | |
| 233 | /* return encoded size of given record of LlcBlock */ |
| 234 | private function f_LlcBlocks_enc_len(LlcBlocks blks) return integer { |
| 235 | var integer sum := 0; |
| 236 | for (var integer i := 0; i < sizeof(blks); i := i+1) { |
| 237 | sum := sum + f_LlcBlock_enc_len(blks[i]); |
| 238 | } |
| 239 | return sum; |
| 240 | } |
| 241 | |
| 242 | private function f_ul_tbf_pull_multi(out LlcBlocks ret, inout UlTbfState us, integer max_len, |
| 243 | boolean is_final) return boolean |
| 244 | { |
| 245 | var integer space_left; |
| 246 | var boolean rc; |
| 247 | ret := {}; |
| 248 | |
| 249 | /* loop as long as we have pending LLC data and space left in the current block... */ |
| 250 | for (space_left := max_len; space_left > 0; space_left := max_len - f_LlcBlocks_enc_len(ret)) { |
| 251 | var LlcBlock lb; |
| 252 | var integer ret_size := sizeof(ret); |
| 253 | if (ret_size > 0) { |
| 254 | rc := f_ul_tbf_pull_one(lb, ret[ret_size-1].hdr, us, space_left, is_final); |
| 255 | } else { |
| 256 | var LlcBlockHdr dummy_hdr; |
| 257 | rc := f_ul_tbf_pull_one(lb, dummy_hdr, us, space_left, is_final); |
| 258 | } |
| 259 | if (rc == false) { |
| 260 | /* we couldn't fill the full RLC block, insufficient LLC Data */ |
| 261 | if (sizeof(ret) == 0) { |
| 262 | /* we couldn't obtain any LlcBlocks at all */ |
| 263 | return false; |
| 264 | } else { |
| 265 | /* we have some LlcBlocks from earlier iterations */ |
| 266 | return true; |
| 267 | } |
| 268 | } |
| 269 | ret := ret & {lb}; |
| 270 | } |
| 271 | return true; |
| 272 | } |
| 273 | |
| 274 | /* Determine 'K' value for given CS (TS 44.060 9.3.1.1) */ |
| 275 | private function f_k_for_cs(GprsCodingScheme cs) return integer { |
| 276 | /* FIXME: EGPRS */ |
| 277 | return 1; |
| 278 | } |
| 279 | |
| 280 | /* TS 44.060 9.3.1.1 */ |
| 281 | private function f_calc_cv(integer nbc, integer bsn_p, integer nts, GprsCodingScheme cs, |
| 282 | integer bs_cv_max) return integer { |
| 283 | var integer dividend := nbc - bsn_p - 1; |
| 284 | var integer k := f_k_for_cs(cs); |
| 285 | var integer divisor := nts * k; |
| 286 | var integer x := f_div_round_up(dividend, divisor); |
| 287 | if (x <= bs_cv_max) { |
| 288 | return x; |
| 289 | } else { |
| 290 | return 15; |
| 291 | } |
| 292 | } |
| 293 | |
| 294 | private function f_rlcmac_hdr_size(boolean tlli_needed) return integer { |
| 295 | var integer ret := 2; |
| 296 | if (tlli_needed) { |
| 297 | ret := ret + 4; |
| 298 | } |
| 299 | return ret; |
| 300 | } |
| 301 | |
| 302 | /* determine countdown value based on remaining length pending */ |
| 303 | private function f_ul_tbf_get_cv(inout UlTbfState us, GprsCodingScheme cs, boolean tlli_needed) |
| 304 | return integer { |
| 305 | var integer hdr_size := f_rlcmac_hdr_size(tlli_needed); /* FIXME: PFI, ... */ |
| 306 | var integer blk_len_net := f_gprs_blocksize(cs) - hdr_size; |
| 307 | var integer num_remain := f_div_round_up(us.total_bytes_remain, blk_len_net); |
| 308 | var integer cv := f_calc_cv(num_remain + sizeof(us.rlc_sent), us.bsn_p, us.num_ts, us.tbf.initial_cs, 14 /* FIXME */); |
| 309 | log("CV=", cv, ", num_rmain=", num_remain, " from ", us); |
| 310 | return cv; |
| 311 | } |
| 312 | |
| 313 | |
| 314 | function f_ul_tbf_get_next_block(out RlcmacUlBlock blk, inout UlTbfState us, inout MmContext mmctx, |
| 315 | boolean tlli_needed := false) return boolean { |
| 316 | var integer hdr_size := f_rlcmac_hdr_size(tlli_needed); /* FIXME: TLLI, PFI, ... */ |
| 317 | var integer len_remain := f_gprs_blocksize(us.tbf.initial_cs) - hdr_size; |
| 318 | var octetstring payload; |
| 319 | var integer cv; |
| 320 | var LlcBlocks llc_blocks; |
| 321 | |
| 322 | cv := f_ul_tbf_get_cv(us, us.tbf.initial_cs, tlli_needed); |
| 323 | /* potentially get multiple payload chunks of multiple LLC PDUs */ |
| 324 | if (f_ul_tbf_pull_multi(llc_blocks, us, len_remain, false) == false) { |
| 325 | return false; |
| 326 | } |
| 327 | |
| 328 | /* include TLLI when needed */ |
| 329 | if (tlli_needed) { |
| 330 | blk := valueof(t_RLCMAC_UL_DATA_TLLI(us.tfi, cv, us.et.v_s, |
| 331 | llc_blocks, false, mmctx.tlli)); |
| 332 | } else { |
| 333 | blk := valueof(t_RLCMAC_UL_DATA(us.tfi, cv, us.et.v_s, llc_blocks, false)); |
| 334 | } |
| 335 | |
| 336 | /* Increment Block Sequence Number */ |
| 337 | us.bsn_p := us.bsn_p + 1; |
| 338 | us.et.v_s := us.bsn_p mod 128; /* FIXME: EGPRS SNS: 2048 */ |
| 339 | |
| 340 | /* append to list of sent blocks */ |
| 341 | us.rlc_sent := us.rlc_sent & { blk }; |
| 342 | |
| 343 | return true; |
| 344 | } |
| 345 | |
| 346 | function f_ul_tbf_process_acknack(inout UlTbfState us, RlcmacDlCtrlBlock db) { |
| 347 | if (ispresent(db.payload.u.ul_ack_nack.gprs)) { |
| 348 | var UlAckNackGprs uan_gprs := db.payload.u.ul_ack_nack.gprs; |
| 349 | if (ispresent(uan_gprs.cont_res_tlli)) { |
| 350 | /* FIXME: check for contention resolution */ |
| 351 | } |
| 352 | var integer i; |
| 353 | /* iterate over received bitmap, ACK each block in our TBF state */ |
| 354 | for (i := lengthof(uan_gprs.ack_nack_desc.receive_block_bitmap)-1; i >= 0; i := i-1) { |
| 355 | if (uan_gprs.ack_nack_desc.receive_block_bitmap[i] == '1'B) { |
| 356 | var integer seq := uan_gprs.ack_nack_desc.starting_seq_nr + i; |
| 357 | f_UlTbf_ack_one_block(us, seq); |
| 358 | } |
| 359 | } |
| 360 | f_UlTbf_check_advance_v_a(us); |
| 361 | } |
| 362 | } |
| 363 | |
Harald Welte | cc5c115 | 2018-03-09 12:54:01 +0100 | [diff] [blame] | 364 | /*********************************************************************** |
| 365 | * Downlink TBF handling |
| 366 | ***********************************************************************/ |
| 367 | |
| 368 | type record RlcEndpointRx { |
| 369 | /* receive state variable V(R) (9.1.5): BSN one higher than highest BSN yet received (mod SNS) */ |
| 370 | integer v_r, |
| 371 | /* receive window state variable V(Q) (9.1.6): Lowest BSN not yet received (mod SNS) */ |
| 372 | integer v_q, |
| 373 | /* receive state array V(N) (9.1.7) */ |
| 374 | bitstring v_n |
| 375 | } |
| 376 | |
| 377 | private function f_RlcEndpointRx_init(inout RlcEndpointRx ep) { |
| 378 | ep.v_r := 0; |
| 379 | ep.v_q := 0; |
| 380 | ep.v_n := int2bit(0, 128); /* FIXME: EGPRS 2048 bits length */ |
| 381 | } |
| 382 | |
| 383 | type record DlTbfPars { |
| 384 | /* Acknowledged mode (true) or unacknowledged (false) */ |
| 385 | boolean ack_mode, |
| 386 | /* Coding Scheme for transmission, determines block size */ |
| 387 | GprsCodingScheme initial_cs, |
| 388 | /* Sequence Number Space */ |
| 389 | integer sns, |
| 390 | /* Window Size */ |
| 391 | integer ws |
| 392 | } |
| 393 | |
| 394 | type record DlTbfState { |
| 395 | /* "const" input state with TBF Data */ |
| 396 | DlTbfPars tbf, |
| 397 | uint8_t num_ts, |
| 398 | |
| 399 | RlcEndpointRx er, |
| 400 | |
| 401 | integer tfi, |
| 402 | |
| 403 | /* list of abstract/decoded RLC PDUs */ |
| 404 | record of RlcmacDlBlock rlc_received |
| 405 | } |
| 406 | |
| 407 | function f_dl_tbf_mod_sns(DlTbfState ds, integer val) return integer |
| 408 | { |
| 409 | return (val mod ds.tbf.sns); |
| 410 | } |
| 411 | |
| 412 | function f_dl_tbf_is_in_window(integer bsn) return boolean { |
| 413 | setverdict(fail, "pleaes implement me"); |
Daniel Willmann | afce866 | 2018-07-06 23:11:32 +0200 | [diff] [blame] | 414 | mtc.stop; |
Harald Welte | cc5c115 | 2018-03-09 12:54:01 +0100 | [diff] [blame] | 415 | } |
| 416 | |
| 417 | function f_dl_tbf_is_received(inout DlTbfState ds, integer bsn) return boolean { |
| 418 | var integer offset_v_r; |
| 419 | |
| 420 | if (not f_dl_tbf_is_in_window(bsn)) { |
| 421 | return false; |
| 422 | } |
| 423 | |
| 424 | /* offset to the end of the received window */ |
| 425 | offset_v_r := f_dl_tbf_mod_sns(ds, ds.er.v_r - 1 - bsn); |
| 426 | if (not (offset_v_r < ds.tbf.ws)) { |
| 427 | return false; |
| 428 | } |
| 429 | |
| 430 | if (ds.er.v_n[bsn mod sns_half] == '1'B) { |
| 431 | return true; |
| 432 | } |
| 433 | |
| 434 | return false; |
| 435 | } |
| 436 | |
| 437 | function f_dl_tbf_mark_received(inout DlTbfState ds, integer bsn) { |
| 438 | ds.er.v_n[bsn mod sns_half] := '1'B; |
| 439 | f_dl_tbf_raise_v_r(ds, bsn); |
| 440 | } |
| 441 | |
| 442 | /* Raise V(Q) if possible */ |
| 443 | function f_dl_tbf_raise_v_q(inout DlTbfState ds, integer bsn) return integer { |
| 444 | var integer count := 0; |
| 445 | while (ds.er.v_q != ds.er.v_r) { |
| 446 | var integer v_q_old := ds.er.v_q; |
| 447 | if (not f_dl_tbf_is_received(ds, v_q_old)) { |
| 448 | break; |
| 449 | } |
| 450 | ds.er.v_q := f_dl_tbf_mod_sns(ds, ds.er.v_q + 1) |
| 451 | log("RLCMAC: Taking block ", v_q_old, " out, raising V(Q) to ", ds.er.v_q); |
| 452 | count := count+1; |
| 453 | } |
| 454 | return count; |
| 455 | } |
| 456 | |
| 457 | function f_dl_tbf_raise_v_r(inout DlTbfState ds, integer bsn) { |
| 458 | var integer offset_v_r := f_dl_tbf_mod_sns(ds, bsn + 1 - ds.er.v_r); |
| 459 | if (offset_v_r < (ds.tbf.sns / 2)) { |
| 460 | for (var integer i := offset_v_r; i > 0; i := i-1) { |
| 461 | /* mark as missing */ |
| 462 | ds.er.v_n[bsn mod sns_half] := '0'B; |
| 463 | //raise_v_r_to(1); |
| 464 | } |
| 465 | log("RLCMAC: Raising V(R) to ", ds.er.v_r); |
| 466 | } |
| 467 | } |
| 468 | |
| 469 | /* process the actual data and update TbfState */ |
| 470 | function f_dl_tbf_process_dl_data(inout DlTbfState ds, RlcmacDlDataBlock db) { |
| 471 | var integer bsn := db.mac_hdr.hdr_ext.bsn; |
| 472 | if (db.mac_hdr.hdr_ext.tfi != ds.tfi) { |
| 473 | setverdict(fail, "Unexpected TFI of DL Data Block ", db); |
Daniel Willmann | afce866 | 2018-07-06 23:11:32 +0200 | [diff] [blame] | 474 | mtc.stop; |
Harald Welte | cc5c115 | 2018-03-09 12:54:01 +0100 | [diff] [blame] | 475 | } |
| 476 | f_dl_tbf_mark_received(ds, bsn); |
| 477 | if (ds.tbf.ack_mode) { |
| 478 | /* In RLC acknowledged mode, the receive window is defined by the receive window |
| 479 | * state variable V(Q) in the following inequality[ V(Q) ≤ BSN < V(Q)+ WS ] modulo |
| 480 | * SNS */ |
| 481 | if (bsn < ds.er.v_q or bsn > ds.er.v_q + ds.tbf.ws) { |
| 482 | setverdict(fail, "Unexpected BSN outside of window ", bsn); |
Daniel Willmann | afce866 | 2018-07-06 23:11:32 +0200 | [diff] [blame] | 483 | mtc.stop; |
Harald Welte | cc5c115 | 2018-03-09 12:54:01 +0100 | [diff] [blame] | 484 | } |
| 485 | |
| 486 | /* In RLC acknowledged mode, the value of V(Q) shall be updated when the RLC |
| 487 | * receiver receives the RLC data block whose BSN is equal to V(Q). The value of |
| 488 | * V(Q) shall then be set to the BSN value of the next RLC data block in the receive |
| 489 | * window (modulo SNS) that has not yet been received, or it shall be set to V(R) if |
| 490 | * all RLC data blocks in the receive window have been received */ |
| 491 | f_dl_tbf_mark_received(ds, bsn); |
| 492 | } else { |
| 493 | /* In RLC unacknowledged mode, if [V(R) - V(Q)] modulo SNS > WS after updating V(R), |
| 494 | * then V(Q) is set to [V(R) - WS] modulo SNS. */ |
| 495 | /* FIXME */ |
| 496 | } |
| 497 | |
| 498 | } |
| 499 | |
Harald Welte | 060e27a | 2018-03-03 20:38:19 +0100 | [diff] [blame] | 500 | |
| 501 | |
| 502 | } |