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
  22 #include "libnetlink.h"
  23 #include "ll_map.h"
  24
  25 extern unsigned int if_nametoindex (const char *);
  26
  27 struct idxmap
  28 {
  29         struct idxmap * next;
  30         unsigned        index;
  31         int             type;
  32         int             alen;
  33         unsigned        flags;
  34         unsigned char   addr[20];
  35         char            name[16];
  36 };
  37
  38 #define IDXMAP_SIZE     1024
  39 static struct idxmap *idxmap[IDXMAP_SIZE];
  40
  41 int ll_remember_index(const struct sockaddr_nl *who,
  42                       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 & (IDXMAP_SIZE - 1);
  61         for (imp = &idxmap[h]; (im=*imp)!=NULL; imp = &im->next)
  62                 if (im->index == ifi->ifi_index)
  63                         break;
  64
  65         if (im == NULL) {
  66                 im = malloc(sizeof(*im));
  67                 if (im == NULL)
  68                         return 0;
  69                 im->next = *imp;
  70                 im->index = ifi->ifi_index;
  71                 *imp = im;
  72         }
  73
  74         im->type = ifi->ifi_type;
  75         im->flags = ifi->ifi_flags;
  76         if (tb[IFLA_ADDRESS]) {
  77                 int alen;
  78                 im->alen = alen = RTA_PAYLOAD(tb[IFLA_ADDRESS]);
  79                 if (alen > sizeof(im->addr))
  80                         alen = sizeof(im->addr);
  81                 memcpy(im->addr, RTA_DATA(tb[IFLA_ADDRESS]), alen);
  82         } else {
  83                 im->alen = 0;
  84                 memset(im->addr, 0, sizeof(im->addr));
  85         }
  86         strcpy(im->name, RTA_DATA(tb[IFLA_IFNAME]));
  87         return 0;
  88 }
  89
  90 const char *ll_idx_n2a(unsigned idx, char *buf)
  91 {
  92         struct idxmap *im;
  93
  94         if (idx == 0)
  95                 return "*";
  96
  97         for (im = idxmap[idx & (IDXMAP_SIZE - 1)]; im; im = im->next)
  98                 if (im->index == idx)
  99                         return im->name;
 100         snprintf(buf, 16, "if%d", idx);
 101         return buf;
 102 }
 103
 104
 105 const char *ll_index_to_name(unsigned idx)
 106 {
 107         static char nbuf[16];
 108
 109         return ll_idx_n2a(idx, nbuf);
 110 }
 111
 112 int ll_index_to_type(unsigned idx)
 113 {
 114         struct idxmap *im;
 115
 116         if (idx == 0)
 117                 return -1;
 118         for (im = idxmap[idx&0xF]; im; im = im->next)
 119                 if (im->index == idx)
 120                         return im->type;
 121         return -1;
 122 }
 123
 124 unsigned ll_index_to_flags(unsigned idx)
 125 {
 126         struct idxmap *im;
 127
 128         if (idx == 0)
 129                 return 0;
 130
 131         for (im = idxmap[idx&0xF]; im; im = im->next)
 132                 if (im->index == idx)
 133                         return im->flags;
 134         return 0;
 135 }
 136
 137 unsigned ll_index_to_addr(unsigned idx, unsigned char *addr,
 138                           unsigned alen)
 139 {
 140         struct idxmap *im;
 141
 142         if (idx == 0)
 143                 return 0;
 144
 145         for (im = idxmap[idx&0xF]; im; im = im->next) {
 146                 if (im->index == idx) {
 147                         if (alen > sizeof(im->addr))
 148                                 alen = sizeof(im->addr);
 149                         if (alen > im->alen)
 150                                 alen = im->alen;
 151                         memcpy(addr, im->addr, alen);
 152                         return alen;
 153                 }
 154         }
 155         return 0;
 156 }
 157
 158 unsigned ll_name_to_index(const char *name)
 159 {
 160         static char ncache[16];
 161         static int icache;
 162         struct idxmap *im;
 163         int i;
 164         unsigned idx;
 165
 166         if (name == NULL)
 167                 return 0;
 168         if (icache && strcmp(name, ncache) == 0)
 169                 return icache;
 170         for (i=0; i<16; i++) {
 171                 for (im = idxmap[i]; im; im = im->next) {
 172                         if (strcmp(im->name, name) == 0) {
 173                                 icache = im->index;
 174                                 strcpy(ncache, name);
 175                                 return im->index;
 176                         }
 177                 }
 178         }
 179
 180         idx = if_nametoindex(name);
 181         if (idx == 0)
 182                 sscanf(name, "if%u", &idx);
 183         return idx;
 184 }
 185
 186 int ll_init_map(struct rtnl_handle *rth)
 187 {
 188         static int initialized;
 189
 190         if (initialized)
 191                 return 0;
 192
 193         if (rtnl_wilddump_request(rth, AF_UNSPEC, RTM_GETLINK) < 0) {
 194                 perror("Cannot send dump request");
 195                 exit(1);
 196         }
 197
 198         if (rtnl_dump_filter(rth, ll_remember_index, &idxmap, NULL, NULL) < 0) {
 199                 fprintf(stderr, "Dump terminated\n");
 200                 exit(1);
 201         }
 202
 203         initialized = 1;
 204
 205         return 0;
 206 }