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1 /*
2  * lib/route/link/inet.c	AF_INET link operations
3  *
4  *	This library is free software; you can redistribute it and/or
5  *	modify it under the terms of the GNU Lesser General Public
6  *	License as published by the Free Software Foundation version 2.1
7  *	of the License.
8  *
9  * Copyright (c) 2010 Thomas Graf <tgraf@suug.ch>
10  */
11 
12 /**
13  * @ingroup link_API
14  * @defgroup link_inet IPv4 Link Module
15  * @brief Implementation of IPv4 specific link attributes
16  *
17  *
18  *
19  * @par Example: Reading the value of IPV4_DEVCONF_FORWARDING
20  * @code
21  * struct nl_cache *cache;
22  * struct rtnl_link *link;
23  * uint32_t value;
24  *
25  * // Allocate a link cache
26  * rtnl_link_alloc_cache(sock, AF_UNSPEC, &cache);
27  *
28  * // Search for the link we wish to see the value from
29  * link = rtnl_link_get_by_name(cache, "eth0");
30  *
31  * // Read the value of the setting IPV4_DEVCONF_FORWARDING
32  * if (rtnl_link_inet_get_conf(link, IPV4_DEVCONF_FORWARDING, &value) < 0)
33  *         // Error: Unable to read config setting
34  *
35  * printf("forwarding is %s\n", value ? "enabled" : "disabled");
36  * @endcode
37  *
38  * @par Example: Changing the value of IPV4_DEVCONF_FOWARDING
39  * @code
40  * //
41  * // ... Continueing from the previous example ...
42  * //
43  *
44  * struct rtnl_link *new;
45  *
46  * // Allocate a new link to store the changes we wish to make.
47  * new = rtnl_link_alloc();
48  *
49  * // Set IPV4_DEVCONF_FORWARDING to '1'
50  * rtnl_link_inet_set_conf(new, IPV4_DEVCONF_FORWARDING, 1);
51  *
52  * // Send the change request to the kernel.
53  * rtnl_link_change(sock, link, new, 0);
54  * @endcode
55  *
56  * @{
57  */
58 
59 
60 #include <netlink-private/netlink.h>
61 #include <netlink/netlink.h>
62 #include <netlink/attr.h>
63 #include <netlink/route/rtnl.h>
64 #include <netlink/route/link/inet.h>
65 #include <netlink-private/route/link/api.h>
66 
67 /** @cond SKIP */
68 struct inet_data
69 {
70 	uint8_t			i_confset[IPV4_DEVCONF_MAX];
71 	uint32_t		i_conf[IPV4_DEVCONF_MAX];
72 };
73 /** @endcond */
74 
inet_alloc(struct rtnl_link * link)75 static void *inet_alloc(struct rtnl_link *link)
76 {
77 	return calloc(1, sizeof(struct inet_data));
78 }
79 
inet_clone(struct rtnl_link * link,void * data)80 static void *inet_clone(struct rtnl_link *link, void *data)
81 {
82 	struct inet_data *id;
83 
84 	if ((id = inet_alloc(link)))
85 		memcpy(id, data, sizeof(*id));
86 
87 	return id;
88 }
89 
inet_free(struct rtnl_link * link,void * data)90 static void inet_free(struct rtnl_link *link, void *data)
91 {
92 	free(data);
93 }
94 
95 static struct nla_policy inet_policy[IFLA_INET_MAX+1] = {
96 	[IFLA_INET_CONF]	= { .minlen = 4 },
97 };
98 
inet_parse_af(struct rtnl_link * link,struct nlattr * attr,void * data)99 static int inet_parse_af(struct rtnl_link *link, struct nlattr *attr, void *data)
100 {
101 	struct inet_data *id = data;
102 	struct nlattr *tb[IFLA_INET_MAX+1];
103 	int err;
104 
105 	err = nla_parse_nested(tb, IFLA_INET_MAX, attr, inet_policy);
106 	if (err < 0)
107 		return err;
108 	if (tb[IFLA_INET_CONF] && nla_len(tb[IFLA_INET_CONF]) % 4)
109 		return -EINVAL;
110 
111 	if (tb[IFLA_INET_CONF]) {
112 		int i;
113 		int len = min_t(int, IPV4_DEVCONF_MAX, nla_len(tb[IFLA_INET_CONF]) / 4);
114 
115 		for (i = 0; i < len; i++)
116 			id->i_confset[i] = 1;
117 		nla_memcpy(&id->i_conf, tb[IFLA_INET_CONF], sizeof(id->i_conf));
118 	}
119 
120 	return 0;
121 }
122 
inet_fill_af(struct rtnl_link * link,struct nl_msg * msg,void * data)123 static int inet_fill_af(struct rtnl_link *link, struct nl_msg *msg, void *data)
124 {
125 	struct inet_data *id = data;
126 	struct nlattr *nla;
127 	int i;
128 
129 	if (!(nla = nla_nest_start(msg, IFLA_INET_CONF)))
130 		return -NLE_MSGSIZE;
131 
132 	for (i = 0; i < IPV4_DEVCONF_MAX; i++)
133 		if (id->i_confset[i])
134 			NLA_PUT_U32(msg, i+1, id->i_conf[i]);
135 
136 	nla_nest_end(msg, nla);
137 
138 	return 0;
139 
140 nla_put_failure:
141 	return -NLE_MSGSIZE;
142 }
143 
144 static const struct trans_tbl inet_devconf[] = {
145 	__ADD(IPV4_DEVCONF_FORWARDING, forwarding),
146 	__ADD(IPV4_DEVCONF_MC_FORWARDING, mc_forwarding),
147 	__ADD(IPV4_DEVCONF_PROXY_ARP, proxy_arp),
148 	__ADD(IPV4_DEVCONF_ACCEPT_REDIRECTS, accept_redirects),
149 	__ADD(IPV4_DEVCONF_SECURE_REDIRECTS, secure_redirects),
150 	__ADD(IPV4_DEVCONF_SEND_REDIRECTS, send_redirects),
151 	__ADD(IPV4_DEVCONF_SHARED_MEDIA, shared_media),
152 	__ADD(IPV4_DEVCONF_RP_FILTER, rp_filter),
153 	__ADD(IPV4_DEVCONF_ACCEPT_SOURCE_ROUTE, accept_source_route),
154 	__ADD(IPV4_DEVCONF_BOOTP_RELAY, bootp_relay),
155 	__ADD(IPV4_DEVCONF_LOG_MARTIANS, log_martians),
156 	__ADD(IPV4_DEVCONF_TAG, tag),
157 	__ADD(IPV4_DEVCONF_ARPFILTER, arpfilter),
158 	__ADD(IPV4_DEVCONF_MEDIUM_ID, medium_id),
159 	__ADD(IPV4_DEVCONF_NOXFRM, noxfrm),
160 	__ADD(IPV4_DEVCONF_NOPOLICY, nopolicy),
161 	__ADD(IPV4_DEVCONF_FORCE_IGMP_VERSION, force_igmp_version),
162 	__ADD(IPV4_DEVCONF_ARP_ANNOUNCE, arp_announce),
163 	__ADD(IPV4_DEVCONF_ARP_IGNORE, arp_ignore),
164 	__ADD(IPV4_DEVCONF_PROMOTE_SECONDARIES, promote_secondaries),
165 	__ADD(IPV4_DEVCONF_ARP_ACCEPT, arp_accept),
166 	__ADD(IPV4_DEVCONF_ARP_NOTIFY, arp_notify),
167 	__ADD(IPV4_DEVCONF_ACCEPT_LOCAL, accept_local),
168 	__ADD(IPV4_DEVCONF_SRC_VMARK, src_vmark),
169 	__ADD(IPV4_DEVCONF_PROXY_ARP_PVLAN, proxy_arp_pvlan),
170 	__ADD(IPV4_DEVCONF_ROUTE_LOCALNET, route_localnet),
171 	__ADD(IPV4_DEVCONF_IGMPV2_UNSOLICITED_REPORT_INTERVAL, igmpv2_unsolicited_report_interval),
172 	__ADD(IPV4_DEVCONF_IGMPV3_UNSOLICITED_REPORT_INTERVAL, igmpv3_unsolicited_report_interval),
173 };
174 
rtnl_link_inet_devconf2str(int type,char * buf,size_t len)175 const char *rtnl_link_inet_devconf2str(int type, char *buf, size_t len)
176 {
177 	return __type2str(type, buf, len, inet_devconf,
178 			  ARRAY_SIZE(inet_devconf));
179 }
180 
rtnl_link_inet_str2devconf(const char * name)181 int rtnl_link_inet_str2devconf(const char *name)
182 {
183 	return __str2type(name, inet_devconf, ARRAY_SIZE(inet_devconf));
184 }
185 
inet_dump_details(struct rtnl_link * link,struct nl_dump_params * p,void * data)186 static void inet_dump_details(struct rtnl_link *link,
187 			      struct nl_dump_params *p, void *data)
188 {
189 	struct inet_data *id = data;
190 	char buf[64];
191 	int i, n = 0;
192 
193 	nl_dump_line(p, "    ipv4 devconf:\n");
194 	nl_dump_line(p, "      ");
195 
196 	for (i = 0; i < IPV4_DEVCONF_MAX; i++) {
197 		nl_dump_line(p, "%-19s %3u",
198 			rtnl_link_inet_devconf2str(i+1, buf, sizeof(buf)),
199 			id->i_confset[i] ? id->i_conf[i] : 0);
200 
201 		if (++n == 3) {
202 			nl_dump(p, "\n");
203 			nl_dump_line(p, "      ");
204 			n = 0;
205 		} else
206 			nl_dump(p, "  ");
207 	}
208 
209 	if (n != 0)
210 		nl_dump(p, "\n");
211 }
212 
213 static struct rtnl_link_af_ops inet_ops = {
214 	.ao_family			= AF_INET,
215 	.ao_alloc			= &inet_alloc,
216 	.ao_clone			= &inet_clone,
217 	.ao_free			= &inet_free,
218 	.ao_parse_af			= &inet_parse_af,
219 	.ao_fill_af			= &inet_fill_af,
220 	.ao_dump[NL_DUMP_DETAILS]	= &inet_dump_details,
221 };
222 
223 /**
224  * Get value of a ipv4 link configuration setting
225  * @arg link		Link object
226  * @arg cfgid		Configuration identifier
227  * @arg res		Result pointer
228  *
229  * Stores the value of the specified configuration setting in the provided
230  * result pointer.
231  *
232  * @return 0 on success or a negative error code.
233  * @return -NLE_RANGE cfgid is out of range, 1..IPV4_DEVCONF_MAX
234  * @return -NLE_NOATTR configuration setting not available
235  * @return -NLE_INVAL cfgid not set. If the link was received via netlink,
236  *                    it means that the cfgid is not supported.
237  */
rtnl_link_inet_get_conf(struct rtnl_link * link,const unsigned int cfgid,uint32_t * res)238 int rtnl_link_inet_get_conf(struct rtnl_link *link, const unsigned int cfgid,
239 			    uint32_t *res)
240 {
241 	struct inet_data *id;
242 
243 	if (cfgid == 0 || cfgid > IPV4_DEVCONF_MAX)
244 		return -NLE_RANGE;
245 
246 	if (!(id = rtnl_link_af_data(link, &inet_ops)))
247 		return -NLE_NOATTR;
248 
249 	if (!id->i_confset[cfgid - 1])
250 		return -NLE_INVAL;
251 	*res = id->i_conf[cfgid - 1];
252 
253 	return 0;
254 }
255 
256 /**
257  * Change value of a ipv4 link configuration setting
258  * @arg link		Link object
259  * @arg cfgid		Configuration identifier
260  * @arg value		New value
261  *
262  * Changes the value in the per link ipv4 configuration array.
263  *
264  * @return 0 on success or a negative error code.
265  * @return -NLE_RANGE cfgid is out of range, 1..IPV4_DEVCONF_MAX
266  * @return -NLE_NOMEM memory allocation failed
267  */
rtnl_link_inet_set_conf(struct rtnl_link * link,const unsigned int cfgid,uint32_t value)268 int rtnl_link_inet_set_conf(struct rtnl_link *link, const unsigned int cfgid,
269 			    uint32_t value)
270 {
271 	struct inet_data *id;
272 
273 	if (!(id = rtnl_link_af_alloc(link, &inet_ops)))
274 		return -NLE_NOMEM;
275 
276 	if (cfgid == 0 || cfgid > IPV4_DEVCONF_MAX)
277 		return -NLE_RANGE;
278 
279 	id->i_confset[cfgid - 1] = 1;
280 	id->i_conf[cfgid - 1] = value;
281 
282 	return 0;
283 }
284 
285 
inet_init(void)286 static void __init inet_init(void)
287 {
288 	rtnl_link_af_register(&inet_ops);
289 }
290 
inet_exit(void)291 static void __exit inet_exit(void)
292 {
293 	rtnl_link_af_unregister(&inet_ops);
294 }
295 
296 /** @} */
297