1/* vi: set sw=4 ts=4: */
2/*
3 * ll_map.c
4 *
5 *		This program is free software; you can redistribute it and/or
6 *		modify it under the terms of the GNU General Public License
7 *		as published by the Free Software Foundation; either version
8 *		2 of the License, or (at your option) any later version.
9 *
10 * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
11 *
12 */
13
14#include <net/if.h>	/* struct ifreq and co. */
15
16#include "libbb.h"
17#include "libnetlink.h"
18#include "ll_map.h"
19
20struct idxmap {
21	struct idxmap *next;
22	int            index;
23	int            type;
24	int            alen;
25	unsigned       flags;
26	unsigned char  addr[8];
27	char           name[16];
28};
29
30static struct idxmap *idxmap[16];
31
32static struct idxmap *find_by_index(int idx)
33{
34	struct idxmap *im;
35
36	for (im = idxmap[idx & 0xF]; im; im = im->next)
37		if (im->index == idx)
38			return im;
39	return NULL;
40}
41
42int ll_remember_index(struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
43{
44	int h;
45	struct ifinfomsg *ifi = NLMSG_DATA(n);
46	struct idxmap *im, **imp;
47	struct rtattr *tb[IFLA_MAX+1];
48
49	if (n->nlmsg_type != RTM_NEWLINK)
50		return 0;
51
52	if (n->nlmsg_len < NLMSG_LENGTH(sizeof(ifi)))
53		return -1;
54
55	memset(tb, 0, sizeof(tb));
56	parse_rtattr(tb, IFLA_MAX, IFLA_RTA(ifi), IFLA_PAYLOAD(n));
57	if (tb[IFLA_IFNAME] == NULL)
58		return 0;
59
60	h = ifi->ifi_index & 0xF;
61
62	for (imp = &idxmap[h]; (im = *imp) != NULL; imp = &im->next)
63		if (im->index == ifi->ifi_index)
64			goto found;
65
66	im = xmalloc(sizeof(*im));
67	im->next = *imp;
68	im->index = ifi->ifi_index;
69	*imp = im;
70 found:
71	im->type = ifi->ifi_type;
72	im->flags = ifi->ifi_flags;
73	if (tb[IFLA_ADDRESS]) {
74		int alen;
75		im->alen = alen = RTA_PAYLOAD(tb[IFLA_ADDRESS]);
76		if (alen > sizeof(im->addr))
77			alen = sizeof(im->addr);
78		memcpy(im->addr, RTA_DATA(tb[IFLA_ADDRESS]), alen);
79	} else {
80		im->alen = 0;
81		memset(im->addr, 0, sizeof(im->addr));
82	}
83	strcpy(im->name, RTA_DATA(tb[IFLA_IFNAME]));
84	return 0;
85}
86
87const char *ll_idx_n2a(int idx, char *buf)
88{
89	struct idxmap *im;
90
91	if (idx == 0)
92		return "*";
93	im = find_by_index(idx);
94	if (im)
95		return im->name;
96	snprintf(buf, 16, "if%d", idx);
97	return buf;
98}
99
100
101const char *ll_index_to_name(int idx)
102{
103	static char nbuf[16];
104
105	return ll_idx_n2a(idx, nbuf);
106}
107
108#ifdef UNUSED
109int ll_index_to_type(int idx)
110{
111	struct idxmap *im;
112
113	if (idx == 0)
114		return -1;
115	im = find_by_index(idx);
116	if (im)
117		return im->type;
118	return -1;
119}
120#endif
121
122unsigned ll_index_to_flags(int idx)
123{
124	struct idxmap *im;
125
126	if (idx == 0)
127		return 0;
128	im = find_by_index(idx);
129	if (im)
130		return im->flags;
131	return 0;
132}
133
134int xll_name_to_index(const char *const name)
135{
136	int ret = 0;
137	int sock_fd;
138
139/* caching is not warranted - no users which repeatedly call it */
140#ifdef UNUSED
141	static char ncache[16];
142	static int icache;
143
144	struct idxmap *im;
145	int i;
146
147	if (name == NULL)
148		goto out;
149	if (icache && strcmp(name, ncache) == 0) {
150		ret = icache;
151		goto out;
152	}
153	for (i = 0; i < 16; i++) {
154		for (im = idxmap[i]; im; im = im->next) {
155			if (strcmp(im->name, name) == 0) {
156				icache = im->index;
157				strcpy(ncache, name);
158				ret = im->index;
159				goto out;
160			}
161		}
162	}
163	/* We have not found the interface in our cache, but the kernel
164	 * may still know about it. One reason is that we may be using
165	 * module on-demand loading, which means that the kernel will
166	 * load the module and make the interface exist only when
167	 * we explicitely request it (check for dev_load() in net/core/dev.c).
168	 * I can think of other similar scenario, but they are less common...
169	 * Jean II */
170#endif
171
172	sock_fd = socket(AF_INET, SOCK_DGRAM, 0);
173	if (sock_fd) {
174		struct ifreq ifr;
175		int tmp;
176
177		strncpy(ifr.ifr_name, name, IFNAMSIZ);
178		ifr.ifr_ifindex = -1;
179		tmp = ioctl(sock_fd, SIOCGIFINDEX, &ifr);
180		close(sock_fd);
181		if (tmp >= 0)
182			/* In theory, we should redump the interface list
183			 * to update our cache, this is left as an exercise
184			 * to the reader... Jean II */
185			ret = ifr.ifr_ifindex;
186	}
187/* out:*/
188	if (ret <= 0)
189		bb_error_msg_and_die("cannot find device \"%s\"", name);
190	return ret;
191}
192
193int ll_init_map(struct rtnl_handle *rth)
194{
195	xrtnl_wilddump_request(rth, AF_UNSPEC, RTM_GETLINK);
196	xrtnl_dump_filter(rth, ll_remember_index, &idxmap);
197	return 0;
198}
199