lib/ll_map.c

   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
  42 static inline struct ll_cache *idxhead(int idx)
  43 {
  44         return idx_head[idx & (IDXMAP_SIZE - 1)];
  45 }
  46
  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
  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
 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
 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
 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
 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
 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
 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, NULL, NULL) < 0) {
 208                 fprintf(stderr, "Dump terminated\n");
 209                 exit(1);
 210         }
 211
 212         initialized = 1;
 213
 214         return 0;
 215 }