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 <net/if.h>
  22
  23 #include "libnetlink.h"
  24 #include "ll_map.h"
  25 #include "list.h"
  26
  27 struct ll_cache {
  28         struct hlist_node idx_hash;
  29         struct hlist_node name_hash;
  30         unsigned        flags;
  31         unsigned        index;
  32         unsigned short  type;
  33         char            name[IFNAMSIZ];
  34 };
  35
  36 #define IDXMAP_SIZE     1024
  37 static struct hlist_head idx_head[IDXMAP_SIZE];
  38 static struct hlist_head name_head[IDXMAP_SIZE];
  39
  40 static struct ll_cache *ll_get_by_index(unsigned index)
  41 {
  42         struct hlist_node *n;
  43         unsigned h = index & (IDXMAP_SIZE - 1);
  44
  45         hlist_for_each(n, &idx_head[h]) {
  46                 struct ll_cache *im
  47                         = container_of(n, struct ll_cache, idx_hash);
  48                 if (im->index == index)
  49                         return im;
  50         }
  51
  52         return NULL;
  53 }
  54
  55 unsigned namehash(const char *str)
  56 {
  57         unsigned hash = 5381;
  58
  59         while (*str)
  60                 hash = ((hash << 5) + hash) + *str++; /* hash * 33 + c */
  61
  62         return hash;
  63 }
  64
  65 static struct ll_cache *ll_get_by_name(const char *name)
  66 {
  67         struct hlist_node *n;
  68         unsigned h = namehash(name) & (IDXMAP_SIZE - 1);
  69
  70         hlist_for_each(n, &name_head[h]) {
  71                 struct ll_cache *im
  72                         = container_of(n, struct ll_cache, name_hash);
  73
  74                 if (strncmp(im->name, name, IFNAMSIZ) == 0)
  75                         return im;
  76         }
  77
  78         return NULL;
  79 }
  80
  81 int ll_remember_index(const struct sockaddr_nl *who,
  82                       struct nlmsghdr *n, void *arg)
  83 {
  84         unsigned int h;
  85         const char *ifname;
  86         struct ifinfomsg *ifi = NLMSG_DATA(n);
  87         struct ll_cache *im;
  88         struct rtattr *tb[IFLA_MAX+1];
  89
  90         if (n->nlmsg_type != RTM_NEWLINK && n->nlmsg_type != RTM_DELLINK)
  91                 return 0;
  92
  93         if (n->nlmsg_len < NLMSG_LENGTH(sizeof(ifi)))
  94                 return -1;
  95
  96         im = ll_get_by_index(ifi->ifi_index);
  97         if (n->nlmsg_type == RTM_DELLINK) {
  98                 if (im) {
  99                         hlist_del(&im->name_hash);
 100                         hlist_del(&im->idx_hash);
 101                         free(im);
 102                 }
 103                 return 0;
 104         }
 105
 106         memset(tb, 0, sizeof(tb));
 107         parse_rtattr(tb, IFLA_MAX, IFLA_RTA(ifi), IFLA_PAYLOAD(n));
 108         ifname = rta_getattr_str(tb[IFLA_IFNAME]);
 109         if (ifname == NULL)
 110                 return 0;
 111
 112         if (im) {
 113                 /* change to existing entry */
 114                 if (strcmp(im->name, ifname) != 0) {
 115                         hlist_del(&im->name_hash);
 116                         h = namehash(ifname) & (IDXMAP_SIZE - 1);
 117                         hlist_add_head(&im->name_hash, &name_head[h]);
 118                 }
 119
 120                 im->flags = ifi->ifi_flags;
 121                 return 0;
 122         }
 123
 124         im = malloc(sizeof(*im));
 125         if (im == NULL)
 126                 return 0;
 127         im->index = ifi->ifi_index;
 128         strcpy(im->name, ifname);
 129         im->type = ifi->ifi_type;
 130         im->flags = ifi->ifi_flags;
 131
 132         h = ifi->ifi_index & (IDXMAP_SIZE - 1);
 133         hlist_add_head(&im->idx_hash, &idx_head[h]);
 134
 135         h = namehash(ifname) & (IDXMAP_SIZE - 1);
 136         hlist_add_head(&im->name_hash, &name_head[h]);
 137
 138         return 0;
 139 }
 140
 141 const char *ll_idx_n2a(unsigned idx, char *buf)
 142 {
 143         const struct ll_cache *im;
 144
 145         if (idx == 0)
 146                 return "*";
 147
 148         im = ll_get_by_index(idx);
 149         if (im)
 150                 return im->name;
 151
 152         if (if_indextoname(idx, buf) == NULL)
 153                 snprintf(buf, IFNAMSIZ, "if%d", idx);
 154
 155         return buf;
 156 }
 157
 158 const char *ll_index_to_name(unsigned idx)
 159 {
 160         static char nbuf[IFNAMSIZ];
 161
 162         return ll_idx_n2a(idx, nbuf);
 163 }
 164
 165 int ll_index_to_type(unsigned idx)
 166 {
 167         const struct ll_cache *im;
 168
 169         if (idx == 0)
 170                 return -1;
 171
 172         im = ll_get_by_index(idx);
 173         return im ? im->type : -1;
 174 }
 175
 176 int ll_index_to_flags(unsigned idx)
 177 {
 178         const struct ll_cache *im;
 179
 180         if (idx == 0)
 181                 return 0;
 182
 183         im = ll_get_by_index(idx);
 184         return im ? im->flags : -1;
 185 }
 186
 187 unsigned ll_name_to_index(const char *name)
 188 {
 189         const struct ll_cache *im;
 190         unsigned idx;
 191
 192         if (name == NULL)
 193                 return 0;
 194
 195         im = ll_get_by_name(name);
 196         if (im)
 197                 return im->index;
 198
 199         idx = if_nametoindex(name);
 200         if (idx == 0)
 201                 sscanf(name, "if%u", &idx);
 202         return idx;
 203 }
 204
 205 void ll_init_map(struct rtnl_handle *rth)
 206 {
 207         static int initialized;
 208
 209         if (initialized)
 210                 return;
 211
 212         if (rtnl_wilddump_request(rth, AF_UNSPEC, RTM_GETLINK) < 0) {
 213                 perror("Cannot send dump request");
 214                 exit(1);
 215         }
 216
 217         if (rtnl_dump_filter(rth, ll_remember_index, NULL) < 0) {
 218                 fprintf(stderr, "Dump terminated\n");
 219                 exit(1);
 220         }
 221
 222         initialized = 1;
 223 }