1 /*
2 * ll_map.c
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 *
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 *
11 */
12
13 #include <stdio.h>
14 #include <stdlib.h>
15 #include <unistd.h>
16 #include <syslog.h>
17 #include <fcntl.h>
18 #include <sys/socket.h>
19 #include <netinet/in.h>
20 #include <string.h>
21 #include <linux/if.h>
22
23 #include "libnetlink.h"
24 #include "ll_map.h"
25
26 extern unsigned int if_nametoindex (const char *);
27
28 struct ll_cache
29 {
30 struct ll_cache *idx_next;
31 unsigned flags;
32 int index;
33 unsigned short type;
34 unsigned short alen;
35 char name[IFNAMSIZ];
36 unsigned char addr[20];
37 };
38
39 #define IDXMAP_SIZE 1024
40 static struct ll_cache *idx_head[IDXMAP_SIZE];
41
idxhead(int idx)42 static inline struct ll_cache *idxhead(int idx)
43 {
44 return idx_head[idx & (IDXMAP_SIZE - 1)];
45 }
46
ll_remember_index(const struct sockaddr_nl * who,struct nlmsghdr * n,void * arg)47 int ll_remember_index(const struct sockaddr_nl *who,
48 struct nlmsghdr *n, void *arg)
49 {
50 int h;
51 struct ifinfomsg *ifi = NLMSG_DATA(n);
52 struct ll_cache *im, **imp;
53 struct rtattr *tb[IFLA_MAX+1];
54
55 if (n->nlmsg_type != RTM_NEWLINK)
56 return 0;
57
58 if (n->nlmsg_len < NLMSG_LENGTH(sizeof(ifi)))
59 return -1;
60
61 memset(tb, 0, sizeof(tb));
62 parse_rtattr(tb, IFLA_MAX, IFLA_RTA(ifi), IFLA_PAYLOAD(n));
63 if (tb[IFLA_IFNAME] == NULL)
64 return 0;
65
66 h = ifi->ifi_index & (IDXMAP_SIZE - 1);
67 for (imp = &idx_head[h]; (im=*imp)!=NULL; imp = &im->idx_next)
68 if (im->index == ifi->ifi_index)
69 break;
70
71 if (im == NULL) {
72 im = malloc(sizeof(*im));
73 if (im == NULL)
74 return 0;
75 im->idx_next = *imp;
76 im->index = ifi->ifi_index;
77 *imp = im;
78 }
79
80 im->type = ifi->ifi_type;
81 im->flags = ifi->ifi_flags;
82 if (tb[IFLA_ADDRESS]) {
83 int alen;
84 im->alen = alen = RTA_PAYLOAD(tb[IFLA_ADDRESS]);
85 if (alen > sizeof(im->addr))
86 alen = sizeof(im->addr);
87 memcpy(im->addr, RTA_DATA(tb[IFLA_ADDRESS]), alen);
88 } else {
89 im->alen = 0;
90 memset(im->addr, 0, sizeof(im->addr));
91 }
92 strcpy(im->name, RTA_DATA(tb[IFLA_IFNAME]));
93 return 0;
94 }
95
ll_idx_n2a(unsigned idx,char * buf)96 const char *ll_idx_n2a(unsigned idx, char *buf)
97 {
98 const struct ll_cache *im;
99
100 if (idx == 0)
101 return "*";
102
103 for (im = idxhead(idx); im; im = im->idx_next)
104 if (im->index == idx)
105 return im->name;
106
107 snprintf(buf, IFNAMSIZ, "if%d", idx);
108 return buf;
109 }
110
111
ll_index_to_name(unsigned idx)112 const char *ll_index_to_name(unsigned idx)
113 {
114 static char nbuf[IFNAMSIZ];
115
116 return ll_idx_n2a(idx, nbuf);
117 }
118
ll_index_to_type(unsigned idx)119 int ll_index_to_type(unsigned idx)
120 {
121 const struct ll_cache *im;
122
123 if (idx == 0)
124 return -1;
125 for (im = idxhead(idx); im; im = im->idx_next)
126 if (im->index == idx)
127 return im->type;
128 return -1;
129 }
130
ll_index_to_flags(unsigned idx)131 unsigned ll_index_to_flags(unsigned idx)
132 {
133 const struct ll_cache *im;
134
135 if (idx == 0)
136 return 0;
137
138 for (im = idxhead(idx); im; im = im->idx_next)
139 if (im->index == idx)
140 return im->flags;
141 return 0;
142 }
143
ll_index_to_addr(unsigned idx,unsigned char * addr,unsigned alen)144 unsigned ll_index_to_addr(unsigned idx, unsigned char *addr,
145 unsigned alen)
146 {
147 const struct ll_cache *im;
148
149 if (idx == 0)
150 return 0;
151
152 for (im = idxhead(idx); im; im = im->idx_next) {
153 if (im->index == idx) {
154 if (alen > sizeof(im->addr))
155 alen = sizeof(im->addr);
156 if (alen > im->alen)
157 alen = im->alen;
158 memcpy(addr, im->addr, alen);
159 return alen;
160 }
161 }
162 return 0;
163 }
164
ll_name_to_index(const char * name)165 unsigned ll_name_to_index(const char *name)
166 {
167 static char ncache[IFNAMSIZ];
168 static int icache;
169 struct ll_cache *im;
170 int i;
171 unsigned idx;
172
173 if (name == NULL)
174 return 0;
175
176 if (icache && strcmp(name, ncache) == 0)
177 return icache;
178
179 for (i=0; i<IDXMAP_SIZE; i++) {
180 for (im = idx_head[i]; im; im = im->idx_next) {
181 if (strcmp(im->name, name) == 0) {
182 icache = im->index;
183 strcpy(ncache, name);
184 return im->index;
185 }
186 }
187 }
188
189 idx = if_nametoindex(name);
190 if (idx == 0)
191 sscanf(name, "if%u", &idx);
192 return idx;
193 }
194
ll_init_map(struct rtnl_handle * rth)195 int ll_init_map(struct rtnl_handle *rth)
196 {
197 static int initialized;
198
199 if (initialized)
200 return 0;
201
202 if (rtnl_wilddump_request(rth, AF_UNSPEC, RTM_GETLINK) < 0) {
203 perror("Cannot send dump request");
204 exit(1);
205 }
206
207 if (rtnl_dump_filter(rth, ll_remember_index, NULL) < 0) {
208 fprintf(stderr, "Dump terminated\n");
209 exit(1);
210 }
211
212 initialized = 1;
213
214 return 0;
215 }
216