1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *	http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17/* NOTICE: This is a clean room re-implementation of libnl */
18
19#include <errno.h>
20#include "netlink/netlink.h"
21#include "netlink/msg.h"
22#include "netlink/attr.h"
23#include "netlink-types.h"
24
25/* Return payload of string attribute. */
26char *nla_get_string(struct nlattr *nla)
27{
28	return (char *) nla_data(nla);
29}
30
31/* Return payload of 16 bit integer attribute. */
32uint16_t nla_get_u16(struct nlattr *nla)
33{
34	return *((uint16_t *) nla_data(nla));
35}
36
37/* Return payload of 32 bit integer attribute. */
38uint32_t nla_get_u32(struct nlattr *nla)
39{
40	return *((uint32_t *) nla_data(nla));
41}
42
43/* Return value of 8 bit integer attribute. */
44uint8_t nla_get_u8(struct nlattr *nla)
45{
46	return *((uint8_t *) nla_data(nla));
47}
48
49/* Return payload of uint64_t attribute. */
50uint64_t nla_get_u64(struct nlattr *nla)
51{
52	uint64_t tmp;
53	nla_memcpy(&tmp, nla, sizeof(tmp));
54	return tmp;
55}
56
57/* Head of payload */
58void *nla_data(const struct nlattr *nla)
59{
60	return (void *) ((char *) nla + NLA_HDRLEN);
61}
62
63/* Return length of the payload . */
64int nla_len(const struct nlattr *nla)
65{
66	return nla->nla_len - NLA_HDRLEN;
67}
68
69int nla_padlen(int payload)
70{
71	return NLA_ALIGN(payload) - payload;
72}
73
74/* Start a new level of nested attributes. */
75struct nlattr *nla_nest_start(struct nl_msg *msg, int attrtype)
76{
77	struct nlattr *start = (struct nlattr *)nlmsg_tail(msg->nm_nlh);
78	int rc;
79
80	rc = nla_put(msg, attrtype, 0, NULL);
81	if (rc < 0)
82		return NULL;
83
84	return start;
85}
86
87/* Finalize nesting of attributes. */
88int nla_nest_end(struct nl_msg *msg, struct nlattr *start)
89{
90	/* Set attribute size */
91	start->nla_len = (unsigned char *)nlmsg_tail(nlmsg_hdr(msg)) -
92				(unsigned char *)start;
93	return 0;
94}
95
96/* Return next attribute in a stream of attributes. */
97struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
98{
99	struct nlattr *next_nla = NULL;
100	if (nla->nla_len >= sizeof(struct nlattr) &&
101	   nla->nla_len <= *remaining){
102		next_nla = (struct nlattr *) \
103			((char *) nla + NLA_ALIGN(nla->nla_len));
104		*remaining = *remaining - NLA_ALIGN(nla->nla_len);
105	}
106
107	return next_nla;
108
109}
110
111/* Check if the attribute header and payload can be accessed safely. */
112int nla_ok(const struct nlattr *nla, int remaining)
113{
114	return remaining > 0 &&
115		nla->nla_len >= sizeof(struct nlattr) &&
116		sizeof(struct nlattr) <= (unsigned int) remaining &&
117		nla->nla_len <= remaining;
118}
119
120/* Create attribute index based on a stream of attributes. */
121/* NOTE: Policy not used ! */
122int nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head,
123	int len, struct nla_policy *policy)
124{
125	struct nlattr *pos;
126	int rem;
127
128	/* First clear table */
129	memset(tb, 0, (maxtype + 1) * sizeof(struct nlattr *));
130
131	nla_for_each_attr(pos, head, len, rem) {
132		int type = nla_type(pos);
133
134		if ((type <= maxtype) && (type != 0))
135			tb[type] = pos;
136	}
137
138	return 0;
139}
140
141
142/* Create attribute index based on nested attribute. */
143int nla_parse_nested(struct nlattr *tb[], int maxtype,
144		struct nlattr *nla, struct nla_policy *policy)
145{
146	return nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy);
147}
148
149
150/* Add a unspecific attribute to netlink message. */
151int nla_put(struct nl_msg *msg, int attrtype, int datalen, const void *data)
152{
153	struct nlattr *nla;
154
155	/* Reserve space and init nla header */
156	nla = nla_reserve(msg, attrtype, datalen);
157	if (nla) {
158		memcpy(nla_data(nla), data, datalen);
159		return 0;
160	}
161
162	return -EINVAL;
163}
164
165/* Add 8 bit integer attribute to netlink message. */
166int nla_put_u8(struct nl_msg *msg, int attrtype, uint8_t value)
167{
168	return nla_put(msg, attrtype, sizeof(uint8_t), &value);
169}
170
171/* Add 16 bit integer attribute to netlink message. */
172int nla_put_u16(struct nl_msg *msg, int attrtype, uint16_t value)
173{
174	return nla_put(msg, attrtype, sizeof(uint16_t), &value);
175}
176
177/* Add 32 bit integer attribute to netlink message. */
178int nla_put_u32(struct nl_msg *msg, int attrtype, uint32_t value)
179{
180	return nla_put(msg, attrtype, sizeof(uint32_t), &value);
181}
182
183/* Add 64 bit integer attribute to netlink message. */
184int nla_put_u64(struct nl_msg *msg, int attrtype, uint64_t value)
185{
186	return nla_put(msg, attrtype, sizeof(uint64_t), &value);
187}
188
189/* Add nested attributes to netlink message. */
190/* Takes the attributes found in the nested message and appends them
191 * to the message msg nested in a container of the type attrtype. The
192 * nested message may not have a family specific header */
193int nla_put_nested(struct nl_msg *msg, int attrtype, struct nl_msg *nested)
194{
195	int rc;
196
197	rc = nla_put(msg, attrtype, nlmsg_attrlen(nlmsg_hdr(nested), 0),
198			nlmsg_attrdata(nlmsg_hdr(nested), 0));
199	return rc;
200
201}
202
203/* Return type of the attribute. */
204int nla_type(const struct nlattr *nla)
205{
206	return (int)nla->nla_type & NLA_TYPE_MASK;
207}
208
209/* Reserves room for an attribute in specified netlink message and fills
210 * in the attribute header (type,length). Return NULL if insufficient space */
211struct nlattr *nla_reserve(struct nl_msg *msg, int attrtype, int data_len)
212{
213
214	struct nlattr *nla;
215	const unsigned int NEW_SIZE = NLMSG_ALIGN(msg->nm_nlh->nlmsg_len) +
216					NLA_ALIGN(NLA_HDRLEN + data_len);
217
218	/* Check enough space for attribute */
219	if (NEW_SIZE > msg->nm_size)
220		return NULL;
221
222	nla = (struct nlattr *)nlmsg_tail(msg->nm_nlh);
223	nla->nla_type = attrtype;
224	nla->nla_len = NLA_HDRLEN + data_len;
225	memset((unsigned char *)nla + nla->nla_len, 0, nla_padlen(data_len));
226	msg->nm_nlh->nlmsg_len = NEW_SIZE;
227	return nla;
228}
229
230/* Copy attribute payload to another memory area. */
231int nla_memcpy(void *dest, struct nlattr *src, int count)
232{
233	if (!src || !dest)
234		return 0;
235	if (count > nla_len(src))
236		count = nla_len(src);
237	memcpy(dest, nla_data(src), count);
238	return count;
239}
240