aboutsummaryrefslogtreecommitdiffstats
path: root/src/rlc.cpp
blob: 0df1655a388171088eed0aa2e41966fc7c88ba84 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
/*
 * Copyright (C) 2013 by Holger Hans Peter Freyther
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#include "tbf.h"
#include "bts.h"
#include "gprs_debug.h"

extern "C" {
#include <osmocom/core/utils.h>
}


uint8_t *gprs_rlc_data::prepare(size_t block_data_len)
{
	/* todo.. only set it once if it turns out to be a bottleneck */
	memset(block, 0x0, sizeof(block));
	memset(block, 0x2b, block_data_len);

	return block;
}

void gprs_rlc_data::put_data(const uint8_t *data, size_t data_len)
{
	memcpy(block, data, data_len);
	len = data_len;
}

void gprs_rlc_v_b::reset()
{
	for (size_t i = 0; i < ARRAY_SIZE(m_v_b); ++i)
		mark_invalid(i);
}

int gprs_rlc_dl_window::resend_needed()
{
	for (uint16_t bsn = v_a(); bsn != v_s(); bsn = (bsn + 1) & mod_sns()) {
		if (m_v_b.is_nacked(bsn) || m_v_b.is_resend(bsn))
			return bsn;
	}

	return -1;
}

int gprs_rlc_dl_window::mark_for_resend()
{
	int resend = 0;

	for (uint16_t bsn = v_a(); bsn != v_s(); bsn = (bsn + 1) & mod_sns()) {
		if (m_v_b.is_unacked(bsn)) {
			/* mark to be re-send */
			m_v_b.mark_resend(bsn);
			resend += 1;
		}
	}

	return resend;
}

int gprs_rlc_dl_window::count_unacked()
{
	uint16_t unacked = 0;
	uint16_t bsn;

	for (bsn = v_a(); bsn != v_s(); bsn = (bsn + 1) & mod_sns()) {
		if (!m_v_b.is_acked(bsn))
			unacked += 1;
	}

	return unacked;
}

static uint16_t bitnum_to_bsn(int bitnum, uint16_t ssn, uint16_t mod_sns)
{
	return (ssn - 1 - bitnum) & mod_sns;
}

void gprs_rlc_dl_window::update(BTS *bts, char *show_rbb, uint8_t ssn,
			uint16_t *lost, uint16_t *received)
{
	/* SSN - 1 is in range V(A)..V(S)-1 */
	for (int bitpos = 0; bitpos < ws(); bitpos++) {
		uint16_t bsn = bitnum_to_bsn(bitpos, ssn, mod_sns());

		if (bsn == ((v_a() - 1) & mod_sns()))
			break;

		if (show_rbb[ws() - 1 - bitpos] == 'R') {
			LOGP(DRLCMACDL, LOGL_DEBUG, "- got ack for BSN=%d\n", bsn);
			if (!m_v_b.is_acked(bsn))
				*received += 1;
			m_v_b.mark_acked(bsn);
		} else {
			LOGP(DRLCMACDL, LOGL_DEBUG, "- got NACK for BSN=%d\n", bsn);
			m_v_b.mark_nacked(bsn);
			bts->rlc_nacked();
			*lost += 1;
		}
	}
}

int gprs_rlc_dl_window::move_window()
{
	int i;
	uint16_t bsn;
	int moved = 0;

	for (i = 0, bsn = v_a(); bsn != v_s(); i++, bsn = (bsn + 1) & mod_sns()) {
		if (m_v_b.is_acked(bsn)) {
			m_v_b.mark_invalid(bsn);
			moved += 1;
		} else
			break;
	}

	return moved;
}

void gprs_rlc_dl_window::state(char *show_v_b)
{
	int i;
	uint16_t bsn;

	for (i = 0, bsn = v_a(); bsn != v_s(); i++, bsn = (bsn + 1) & mod_sns()) {
		uint16_t index = bsn & mod_sns_half();
		show_v_b[i] = m_v_b.get_state(index);
		if (show_v_b[i] == 0)
			show_v_b[i] = ' ';
	}
	show_v_b[i] = '\0';
}

void gprs_rlc_v_n::reset()
{
	memset(m_v_n, 0x0, sizeof(m_v_n));
}

/* Update the receive block bitmap */
void gprs_rlc_ul_window::update_rbb(char *rbb)
{
	int i;
	for (i=0; i < ws(); i++) {
		if (m_v_n.is_received(ssn()-1-i))
			rbb[ws()-1-i] = 'R';
		else
			rbb[ws()-1-i] = 'I';
	}
}

/* Raise V(R) to highest received sequence number not received. */
void gprs_rlc_ul_window::raise_v_r(const uint16_t bsn)
{
	uint16_t offset_v_r;
	offset_v_r = (bsn + 1 - v_r()) & mod_sns();
	/* Positive offset, so raise. */
	if (offset_v_r < (sns() >> 1)) {
		while (offset_v_r--) {
			if (offset_v_r) /* all except the received block */
				m_v_n.mark_missing(v_r());
			raise_v_r_to(1);
		}
		LOGP(DRLCMACUL, LOGL_DEBUG, "- Raising V(R) to %d\n", v_r());
	}
}

/*
 * Raise V(Q) if possible. This is looped until there is a gap
 * (non received block) or the window is empty.
 */
uint16_t gprs_rlc_ul_window::raise_v_q()
{
	uint16_t count = 0;

	while (v_q() != v_r()) {
		if (!m_v_n.is_received(v_q()))
			break;
		LOGP(DRLCMACUL, LOGL_DEBUG, "- Taking block %d out, raising "
			"V(Q) to %d\n", v_q(), (v_q() + 1) & mod_sns());
		raise_v_q(1);
		count += 1;
	}

	return count;
}

uint16_t gprs_rlc_ul_window::receive_bsn(const uint16_t bsn)
{
	m_v_n.mark_received(bsn);
	raise_v_r(bsn);

	return raise_v_q();
}