aboutsummaryrefslogtreecommitdiffstats
path: root/net/caif/cfrfml.c
blob: 61d7617d924912347325a5db483172794e6df33a (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
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
/*
 * Copyright (C) ST-Ericsson AB 2010
 * Author:	Sjur Brendeland
 * License terms: GNU General Public License (GPL) version 2
 */

#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__

#include <linux/stddef.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <asm/unaligned.h>
#include <net/caif/caif_layer.h>
#include <net/caif/cfsrvl.h>
#include <net/caif/cfpkt.h>

#define container_obj(layr) container_of(layr, struct cfrfml, serv.layer)
#define RFM_SEGMENTATION_BIT 0x01
#define RFM_HEAD_SIZE 7

static int cfrfml_receive(struct cflayer *layr, struct cfpkt *pkt);
static int cfrfml_transmit(struct cflayer *layr, struct cfpkt *pkt);

struct cfrfml {
	struct cfsrvl serv;
	struct cfpkt *incomplete_frm;
	int fragment_size;
	u8  seghead[6];
	u16 pdu_size;
	/* Protects serialized processing of packets */
	spinlock_t sync;
};

static void cfrfml_release(struct cflayer *layer)
{
	struct cfsrvl *srvl = container_of(layer, struct cfsrvl, layer);
	struct cfrfml *rfml = container_obj(&srvl->layer);

	if (rfml->incomplete_frm)
		cfpkt_destroy(rfml->incomplete_frm);

	kfree(srvl);
}

struct cflayer *cfrfml_create(u8 channel_id, struct dev_info *dev_info,
			      int mtu_size)
{
	int tmp;
	struct cfrfml *this = kzalloc(sizeof(struct cfrfml), GFP_ATOMIC);

	if (!this)
		return NULL;

	cfsrvl_init(&this->serv, channel_id, dev_info, false);
	this->serv.release = cfrfml_release;
	this->serv.layer.receive = cfrfml_receive;
	this->serv.layer.transmit = cfrfml_transmit;

	/* Round down to closest multiple of 16 */
	tmp = (mtu_size - RFM_HEAD_SIZE - 6) / 16;
	tmp *= 16;

	this->fragment_size = tmp;
	spin_lock_init(&this->sync);
	snprintf(this->serv.layer.name, CAIF_LAYER_NAME_SZ,
		"rfm%d", channel_id);

	return &this->serv.layer;
}

static struct cfpkt *rfm_append(struct cfrfml *rfml, char *seghead,
				struct cfpkt *pkt, int *err)
{
	struct cfpkt *tmppkt;
	*err = -EPROTO;
	/* n-th but not last segment */

	if (cfpkt_extr_head(pkt, seghead, 6) < 0)
		return NULL;

	/* Verify correct header */
	if (memcmp(seghead, rfml->seghead, 6) != 0)
		return NULL;

	tmppkt = cfpkt_append(rfml->incomplete_frm, pkt,
			rfml->pdu_size + RFM_HEAD_SIZE);

	/* If cfpkt_append failes input pkts are not freed */
	*err = -ENOMEM;
	if (tmppkt == NULL)
		return NULL;

	*err = 0;
	return tmppkt;
}

static int cfrfml_receive(struct cflayer *layr, struct cfpkt *pkt)
{
	u8 tmp;
	bool segmented;
	int err;
	u8 seghead[6];
	struct cfrfml *rfml;
	struct cfpkt *tmppkt = NULL;

	caif_assert(layr->up != NULL);
	caif_assert(layr->receive != NULL);
	rfml = container_obj(layr);
	spin_lock(&rfml->sync);

	err = -EPROTO;
	if (cfpkt_extr_head(pkt, &tmp, 1) < 0)
		goto out;
	segmented = tmp & RFM_SEGMENTATION_BIT;

	if (segmented) {
		if (rfml->incomplete_frm == NULL) {
			/* Initial Segment */
			if (cfpkt_peek_head(pkt, rfml->seghead, 6) < 0)
				goto out;

			rfml->pdu_size = get_unaligned_le16(rfml->seghead+4);

			if (cfpkt_erroneous(pkt))
				goto out;
			rfml->incomplete_frm = pkt;
			pkt = NULL;
		} else {

			tmppkt = rfm_append(rfml, seghead, pkt, &err);
			if (tmppkt == NULL)
				goto out;

			if (cfpkt_erroneous(tmppkt))
				goto out;

			rfml->incomplete_frm = tmppkt;


			if (cfpkt_erroneous(tmppkt))
				goto out;
		}
		err = 0;
		goto out;
	}

	if (rfml->incomplete_frm) {

		/* Last Segment */
		tmppkt = rfm_append(rfml, seghead, pkt, &err);
		if (tmppkt == NULL)
			goto out;

		if (cfpkt_erroneous(tmppkt))
			goto out;

		rfml->incomplete_frm = NULL;
		pkt = tmppkt;
		tmppkt = NULL;

		/* Verify that length is correct */
		err = EPROTO;
		if (rfml->pdu_size != cfpkt_getlen(pkt) - RFM_HEAD_SIZE + 1)
			goto out;
	}

	err = rfml->serv.layer.up->receive(rfml->serv.layer.up, pkt);

out:

	if (err != 0) {
		if (tmppkt)
			cfpkt_destroy(tmppkt);
		if (pkt)
			cfpkt_destroy(pkt);
		if (rfml->incomplete_frm)
			cfpkt_destroy(rfml->incomplete_frm);
		rfml->incomplete_frm = NULL;

		pr_info("Connection error %d triggered on RFM link\n", err);

		/* Trigger connection error upon failure.*/
		layr->up->ctrlcmd(layr->up, CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND,
					rfml->serv.dev_info.id);
	}
	spin_unlock(&rfml->sync);

	if (unlikely(err == -EAGAIN))
		/* It is not possible to recover after drop of a fragment */
		err = -EIO;

	return err;
}


static int cfrfml_transmit_segment(struct cfrfml *rfml, struct cfpkt *pkt)
{
	caif_assert(cfpkt_getlen(pkt) < rfml->fragment_size + RFM_HEAD_SIZE);

	/* Add info for MUX-layer to route the packet out. */
	cfpkt_info(pkt)->channel_id = rfml->serv.layer.id;

	/*
	 * To optimize alignment, we add up the size of CAIF header before
	 * payload.
	 */
	cfpkt_info(pkt)->hdr_len = RFM_HEAD_SIZE;
	cfpkt_info(pkt)->dev_info = &rfml->serv.dev_info;

	return rfml->serv.layer.dn->transmit(rfml->serv.layer.dn, pkt);
}

static int cfrfml_transmit(struct cflayer *layr, struct cfpkt *pkt)
{
	int err;
	u8 seg;
	u8 head[6];
	struct cfpkt *rearpkt = NULL;
	struct cfpkt *frontpkt = pkt;
	struct cfrfml *rfml = container_obj(layr);

	caif_assert(layr->dn != NULL);
	caif_assert(layr->dn->transmit != NULL);

	if (!cfsrvl_ready(&rfml->serv, &err))
		goto out;

	err = -EPROTO;
	if (cfpkt_getlen(pkt) <= RFM_HEAD_SIZE-1)
		goto out;

	err = 0;
	if (cfpkt_getlen(pkt) > rfml->fragment_size + RFM_HEAD_SIZE)
		err = cfpkt_peek_head(pkt, head, 6);

	if (err < 0)
		goto out;

	while (cfpkt_getlen(frontpkt) > rfml->fragment_size + RFM_HEAD_SIZE) {

		seg = 1;
		err = -EPROTO;

		if (cfpkt_add_head(frontpkt, &seg, 1) < 0)
			goto out;
		/*
		 * On OOM error cfpkt_split returns NULL.
		 *
		 * NOTE: Segmented pdu is not correctly aligned.
		 * This has negative performance impact.
		 */

		rearpkt = cfpkt_split(frontpkt, rfml->fragment_size);
		if (rearpkt == NULL)
			goto out;

		err = cfrfml_transmit_segment(rfml, frontpkt);

		if (err != 0) {
			frontpkt = NULL;
			goto out;
		}

		frontpkt = rearpkt;
		rearpkt = NULL;

		err = -ENOMEM;
		if (frontpkt == NULL)
			goto out;
		err = -EPROTO;
		if (cfpkt_add_head(frontpkt, head, 6) < 0)
			goto out;

	}

	seg = 0;
	err = -EPROTO;

	if (cfpkt_add_head(frontpkt, &seg, 1) < 0)
		goto out;

	err = cfrfml_transmit_segment(rfml, frontpkt);

	frontpkt = NULL;
out:

	if (err != 0) {
		pr_info("Connection error %d triggered on RFM link\n", err);
		/* Trigger connection error upon failure.*/

		layr->up->ctrlcmd(layr->up, CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND,
					rfml->serv.dev_info.id);

		if (rearpkt)
			cfpkt_destroy(rearpkt);

		if (frontpkt)
			cfpkt_destroy(frontpkt);
	}

	return err;
}

Privacy Policy