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 <fcntl.h>
  17 #include <sys/socket.h>
  18 #include <netinet/in.h>
  19 #include <string.h>
  20 #include <net/if.h>
  21
  22 #include "libnetlink.h"
  23 #include "ll_map.h"
  24 #include "list.h"
  25
  26 struct ll_cache {
  27         struct hlist_node idx_hash;
  28         struct hlist_node name_hash;
  29         unsigned        flags;
  30         unsigned        index;
  31         unsigned short  type;
  32         char            name[];
  33 };
  34
  35 #define IDXMAP_SIZE     1024
  36 static struct hlist_head idx_head[IDXMAP_SIZE];
  37 static struct hlist_head name_head[IDXMAP_SIZE];
  38
  39 static struct ll_cache *ll_get_by_index(unsigned index)
  40 {
  41         struct hlist_node *n;
  42         unsigned h = index & (IDXMAP_SIZE - 1);
  43
  44         hlist_for_each(n, &idx_head[h]) {
  45                 struct ll_cache *im
  46                         = container_of(n, struct ll_cache, idx_hash);
  47                 if (im->index == index)
  48                         return im;
  49         }
  50
  51         return NULL;
  52 }
  53
  54 unsigned namehash(const char *str)
  55 {
  56         unsigned hash = 5381;
  57
  58         while (*str)
  59                 hash = ((hash << 5) + hash) + *str++; /* hash * 33 + c */
  60
  61         return hash;
  62 }
  63
  64 static struct ll_cache *ll_get_by_name(const char *name)
  65 {
  66         struct hlist_node *n;
  67         unsigned h = namehash(name) & (IDXMAP_SIZE - 1);
  68
  69         hlist_for_each(n, &name_head[h]) {
  70                 struct ll_cache *im
  71                         = container_of(n, struct ll_cache, name_hash);
  72
  73                 if (strncmp(im->name, name, IFNAMSIZ) == 0)
  74                         return im;
  75         }
  76
  77         return NULL;
  78 }
  79
  80 int ll_remember_index(const struct sockaddr_nl *who,
  81                       struct nlmsghdr *n, void *arg)
  82 {
  83         unsigned int h;
  84         const char *ifname;
  85         struct ifinfomsg *ifi = NLMSG_DATA(n);
  86         struct ll_cache *im;
  87         struct rtattr *tb[IFLA_MAX+1];
  88
  89         if (n->nlmsg_type != RTM_NEWLINK && n->nlmsg_type != RTM_DELLINK)
  90                 return 0;
  91
  92         if (n->nlmsg_len < NLMSG_LENGTH(sizeof(*ifi)))
  93                 return -1;
  94
  95         im = ll_get_by_index(ifi->ifi_index);
  96         if (n->nlmsg_type == RTM_DELLINK) {
  97                 if (im) {
  98                         hlist_del(&im->name_hash);
  99                         hlist_del(&im->idx_hash);
 100                         free(im);
 101                 }
 102                 return 0;
 103         }
 104
 105         parse_rtattr(tb, IFLA_MAX, IFLA_RTA(ifi), IFLA_PAYLOAD(n));
 106         ifname = rta_getattr_str(tb[IFLA_IFNAME]);
 107         if (ifname == NULL)
 108                 return 0;
 109
 110         if (im) {
 111                 /* change to existing entry */
 112                 if (strcmp(im->name, ifname) != 0) {
 113                         hlist_del(&im->name_hash);
 114                         h = namehash(ifname) & (IDXMAP_SIZE - 1);
 115                         hlist_add_head(&im->name_hash, &name_head[h]);
 116                 }
 117
 118                 im->flags = ifi->ifi_flags;
 119                 return 0;
 120         }
 121
 122         im = malloc(sizeof(*im) + strlen(ifname) + 1);
 123         if (im == NULL)
 124                 return 0;
 125         im->index = ifi->ifi_index;
 126         strcpy(im->name, ifname);
 127         im->type = ifi->ifi_type;
 128         im->flags = ifi->ifi_flags;
 129
 130         h = ifi->ifi_index & (IDXMAP_SIZE - 1);
 131         hlist_add_head(&im->idx_hash, &idx_head[h]);
 132
 133         h = namehash(ifname) & (IDXMAP_SIZE - 1);
 134         hlist_add_head(&im->name_hash, &name_head[h]);
 135
 136         return 0;
 137 }
 138
 139 const char *ll_idx_n2a(unsigned idx, char *buf)
 140 {
 141         const struct ll_cache *im;
 142
 143         if (idx == 0)
 144                 return "*";
 145
 146         im = ll_get_by_index(idx);
 147         if (im)
 148                 return im->name;
 149
 150         if (if_indextoname(idx, buf) == NULL)
 151                 snprintf(buf, IFNAMSIZ, "if%d", idx);
 152
 153         return buf;
 154 }
 155
 156 const char *ll_index_to_name(unsigned idx)
 157 {
 158         static char nbuf[IFNAMSIZ];
 159
 160         return ll_idx_n2a(idx, nbuf);
 161 }
 162
 163 int ll_index_to_type(unsigned idx)
 164 {
 165         const struct ll_cache *im;
 166
 167         if (idx == 0)
 168                 return -1;
 169
 170         im = ll_get_by_index(idx);
 171         return im ? im->type : -1;
 172 }
 173
 174 int ll_index_to_flags(unsigned idx)
 175 {
 176         const struct ll_cache *im;
 177
 178         if (idx == 0)
 179                 return 0;
 180
 181         im = ll_get_by_index(idx);
 182         return im ? im->flags : -1;
 183 }
 184
 185 unsigned ll_name_to_index(const char *name)
 186 {
 187         const struct ll_cache *im;
 188         unsigned idx;
 189
 190         if (name == NULL)
 191                 return 0;
 192
 193         im = ll_get_by_name(name);
 194         if (im)
 195                 return im->index;
 196
 197         idx = if_nametoindex(name);
 198         if (idx == 0)
 199                 sscanf(name, "if%u", &idx);
 200         return idx;
 201 }
 202
 203 void ll_init_map(struct rtnl_handle *rth)
 204 {
 205         static int initialized;
 206
 207         if (initialized)
 208                 return;
 209
 210         if (rtnl_wilddump_request(rth, AF_UNSPEC, RTM_GETLINK) < 0) {
 211                 perror("Cannot send dump request");
 212                 exit(1);
 213         }
 214
 215         if (rtnl_dump_filter(rth, ll_remember_index, NULL) < 0) {
 216                 fprintf(stderr, "Dump terminated\n");
 217                 exit(1);
 218         }
 219
 220         initialized = 1;
 221 }