aboutsummaryrefslogtreecommitdiffstats
path: root/gpxe/src/core/nvo.c
blob: 3dbf51d3f36ea1247c9978938b5530061513f4bc (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
/*
 * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * 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 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

FILE_LICENCE ( GPL2_OR_LATER );

#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <gpxe/dhcp.h>
#include <gpxe/nvs.h>
#include <gpxe/nvo.h>

/** @file
 *
 * Non-volatile stored options
 *
 */

/**
 * Calculate checksum over non-volatile stored options
 *
 * @v nvo		Non-volatile options block
 * @ret sum		Checksum
 */
static unsigned int nvo_checksum ( struct nvo_block *nvo ) {
	uint8_t *data = nvo->data;
	uint8_t sum = 0;
	unsigned int i;

	for ( i = 0 ; i < nvo->total_len ; i++ ) {
		sum += *(data++);
	}
	return sum;
}

/**
 * Load non-volatile stored options from non-volatile storage device
 *
 * @v nvo		Non-volatile options block
 * @ret rc		Return status code
 */
static int nvo_load ( struct nvo_block *nvo ) {
	void *data = nvo->data;
	struct nvo_fragment *frag;
	int rc;

	/* Read data a fragment at a time */
	for ( frag = nvo->fragments ; frag->len ; frag++ ) {
		if ( ( rc = nvs_read ( nvo->nvs, frag->address, data,
				       frag->len ) ) != 0 ) {
			DBGC ( nvo, "NVO %p could not read %zd bytes at "
			       "%#04x\n", nvo, frag->len, frag->address );
			return rc;
		}
		data += frag->len;
	}

	DBGC ( nvo, "NVO %p loaded from non-volatile storage\n", nvo );
	return 0;
}

/**
 * Save non-volatile stored options back to non-volatile storage device
 *
 * @v nvo		Non-volatile options block
 * @ret rc		Return status code
 */
static int nvo_save ( struct nvo_block *nvo ) {
	void *data = nvo->data;
	uint8_t *checksum = data;
	struct nvo_fragment *frag;
	int rc;

	/* Recalculate checksum */
	*checksum -= nvo_checksum ( nvo );

	/* Write data a fragment at a time */
	for ( frag = nvo->fragments ; frag->len ; frag++ ) {
		if ( ( rc = nvs_write ( nvo->nvs, frag->address, data,
					frag->len ) ) != 0 ) {
			DBGC ( nvo, "NVO %p could not write %zd bytes at "
			       "%#04x\n", nvo, frag->len, frag->address );
			return rc;
		}
		data += frag->len;
	}

	DBGC ( nvo, "NVO %p saved to non-volatile storage\n", nvo );
	return 0;
}

/**
 * Parse stored options
 *
 * @v nvo		Non-volatile options block
 *
 * Verifies that the options data is valid, and configures the DHCP
 * options block.  If the data is not valid, it is replaced with an
 * empty options block.
 */
static void nvo_init_dhcpopts ( struct nvo_block *nvo ) {
	uint8_t *options_data;
	size_t options_len;

	/* Steal one byte for the checksum */
	options_data = ( nvo->data + 1 );
	options_len = ( nvo->total_len - 1 );

	/* If checksum fails, or options data starts with a zero,
	 * assume the whole block is invalid.  This should capture the
	 * case of random initial contents.
	 */
	if ( ( nvo_checksum ( nvo ) != 0 ) || ( options_data[0] == 0 ) ) {
		DBGC ( nvo, "NVO %p has checksum %02x and initial byte %02x; "
		       "assuming empty\n", nvo, nvo_checksum ( nvo ),
		       options_data[0] );
		memset ( nvo->data, 0, nvo->total_len );
	}

	dhcpopt_init ( &nvo->dhcpopts, options_data, options_len );
}

/**
 * Store value of NVO setting
 *
 * @v settings		Settings block
 * @v setting		Setting to store
 * @v data		Setting data, or NULL to clear setting
 * @v len		Length of setting data
 * @ret rc		Return status code
 */
static int nvo_store ( struct settings *settings, struct setting *setting,
		       const void *data, size_t len ) {
	struct nvo_block *nvo =
		container_of ( settings, struct nvo_block, settings );
	int rc;

	/* Update stored options */
	if ( ( rc = dhcpopt_store ( &nvo->dhcpopts, setting->tag,
				    data, len ) ) != 0 ) {
		DBGC ( nvo, "NVO %p could not store %zd bytes: %s\n",
		       nvo, len, strerror ( rc ) );
		return rc;
	}

	/* Save updated options to NVS */
	if ( ( rc = nvo_save ( nvo ) ) != 0 )
		return rc;

	return 0;
}

/**
 * Fetch value of NVO setting
 *
 * @v settings		Settings block
 * @v setting		Setting to fetch
 * @v data		Buffer to fill with setting data
 * @v len		Length of buffer
 * @ret len		Length of setting data, or negative error
 *
 * The actual length of the setting will be returned even if
 * the buffer was too small.
 */
static int nvo_fetch ( struct settings *settings, struct setting *setting,
		       void *data, size_t len ) {
	struct nvo_block *nvo =
		container_of ( settings, struct nvo_block, settings );

	return dhcpopt_fetch ( &nvo->dhcpopts, setting->tag, data, len );
}

/** NVO settings operations */
static struct settings_operations nvo_settings_operations = {
	.store = nvo_store,
	.fetch = nvo_fetch,
};

/**
 * Initialise non-volatile stored options
 *
 * @v nvo		Non-volatile options block
 * @v nvs		Underlying non-volatile storage device
 * @v fragments		List of option-containing fragments
 * @v refcnt		Containing object reference counter, or NULL
 */
void nvo_init ( struct nvo_block *nvo, struct nvs_device *nvs,
		struct nvo_fragment *fragments, struct refcnt *refcnt ) {
	nvo->nvs = nvs;
	nvo->fragments = fragments;
	settings_init ( &nvo->settings, &nvo_settings_operations, refcnt,
			"nvo", 0 );
}

/**
 * Register non-volatile stored options
 *
 * @v nvo		Non-volatile options block
 * @v parent		Parent settings block, or NULL
 * @ret rc		Return status code
 */
int register_nvo ( struct nvo_block *nvo, struct settings *parent ) {
	struct nvo_fragment *fragment = nvo->fragments;
	int rc;

	/* Calculate total length of all fragments */
	for ( fragment = nvo->fragments ; fragment->len ; fragment++ )
		nvo->total_len += fragment->len;

	/* Allocate memory for options and read in from NVS */
	nvo->data = malloc ( nvo->total_len );
	if ( ! nvo->data ) {
		DBGC ( nvo, "NVO %p could not allocate %zd bytes\n",
		       nvo, nvo->total_len );
		rc = -ENOMEM;
		goto err_malloc;
	}
	if ( ( rc = nvo_load ( nvo ) ) != 0 )
		goto err_load;

	/* Verify and register options */
	nvo_init_dhcpopts ( nvo );
	if ( ( rc = register_settings ( &nvo->settings, parent ) ) != 0 )
		goto err_register;

	DBGC ( nvo, "NVO %p registered\n", nvo );
	return 0;
	
 err_register:
 err_load:
	free ( nvo->data );
	nvo->data = NULL;
 err_malloc:
	return rc;
}

/**
 * Unregister non-volatile stored options
 *
 * @v nvo		Non-volatile options block
 */
void unregister_nvo ( struct nvo_block *nvo ) {
	unregister_settings ( &nvo->settings );
	free ( nvo->data );
	nvo->data = NULL;
	DBGC ( nvo, "NVO %p unregistered\n", nvo );
}