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187 lines
4.0 KiB
C
187 lines
4.0 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* ll_map.c
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
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*
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*/
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#include "libbb.h"
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#include <string.h>
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#include "libnetlink.h"
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#include "ll_map.h"
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#include <sys/socket.h> /* socket() */
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#include <net/if.h> /* struct ifreq and co. */
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#include <sys/ioctl.h> /* ioctl() & SIOCGIFINDEX */
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struct idxmap {
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struct idxmap * next;
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int index;
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int type;
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int alen;
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unsigned flags;
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unsigned char addr[8];
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char name[16];
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};
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static struct idxmap *idxmap[16];
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int ll_remember_index(struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
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{
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int h;
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struct ifinfomsg *ifi = NLMSG_DATA(n);
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struct idxmap *im, **imp;
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struct rtattr *tb[IFLA_MAX+1];
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if (n->nlmsg_type != RTM_NEWLINK)
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return 0;
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if (n->nlmsg_len < NLMSG_LENGTH(sizeof(ifi)))
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return -1;
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memset(tb, 0, sizeof(tb));
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parse_rtattr(tb, IFLA_MAX, IFLA_RTA(ifi), IFLA_PAYLOAD(n));
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if (tb[IFLA_IFNAME] == NULL)
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return 0;
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h = ifi->ifi_index&0xF;
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for (imp=&idxmap[h]; (im=*imp)!=NULL; imp = &im->next)
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if (im->index == ifi->ifi_index)
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break;
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if (im == NULL) {
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im = xmalloc(sizeof(*im));
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im->next = *imp;
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im->index = ifi->ifi_index;
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*imp = im;
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}
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im->type = ifi->ifi_type;
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im->flags = ifi->ifi_flags;
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if (tb[IFLA_ADDRESS]) {
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int alen;
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im->alen = alen = RTA_PAYLOAD(tb[IFLA_ADDRESS]);
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if (alen > sizeof(im->addr))
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alen = sizeof(im->addr);
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memcpy(im->addr, RTA_DATA(tb[IFLA_ADDRESS]), alen);
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} else {
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im->alen = 0;
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memset(im->addr, 0, sizeof(im->addr));
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}
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strcpy(im->name, RTA_DATA(tb[IFLA_IFNAME]));
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return 0;
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}
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const char *ll_idx_n2a(int idx, char *buf)
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{
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struct idxmap *im;
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if (idx == 0)
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return "*";
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for (im = idxmap[idx&0xF]; im; im = im->next)
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if (im->index == idx)
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return im->name;
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snprintf(buf, 16, "if%d", idx);
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return buf;
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}
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const char *ll_index_to_name(int idx)
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{
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static char nbuf[16];
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return ll_idx_n2a(idx, nbuf);
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}
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int ll_index_to_type(int idx)
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{
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struct idxmap *im;
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if (idx == 0)
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return -1;
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for (im = idxmap[idx&0xF]; im; im = im->next)
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if (im->index == idx)
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return im->type;
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return -1;
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}
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unsigned ll_index_to_flags(int idx)
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{
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struct idxmap *im;
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if (idx == 0)
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return 0;
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for (im = idxmap[idx&0xF]; im; im = im->next)
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if (im->index == idx)
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return im->flags;
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return 0;
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}
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int ll_name_to_index(char *name)
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{
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static char ncache[16];
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static int icache;
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struct idxmap *im;
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int sock_fd;
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int i;
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if (name == NULL)
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return 0;
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if (icache && strcmp(name, ncache) == 0)
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return icache;
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for (i=0; i<16; i++) {
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for (im = idxmap[i]; im; im = im->next) {
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if (strcmp(im->name, name) == 0) {
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icache = im->index;
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strcpy(ncache, name);
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return im->index;
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}
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}
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}
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/* We have not found the interface in our cache, but the kernel
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* may still know about it. One reason is that we may be using
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* module on-demand loading, which means that the kernel will
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* load the module and make the interface exist only when
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* we explicitely request it (check for dev_load() in net/core/dev.c).
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* I can think of other similar scenario, but they are less common...
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* Jean II */
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sock_fd = socket(AF_INET, SOCK_DGRAM, 0);
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if (sock_fd) {
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struct ifreq ifr;
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int ret;
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strncpy(ifr.ifr_name, name, IFNAMSIZ);
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ifr.ifr_ifindex = -1;
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ret = ioctl(sock_fd, SIOCGIFINDEX, &ifr);
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close(sock_fd);
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if (ret >= 0)
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/* In theory, we should redump the interface list
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* to update our cache, this is left as an exercise
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* to the reader... Jean II */
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return ifr.ifr_ifindex;
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}
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return 0;
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}
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int ll_init_map(struct rtnl_handle *rth)
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{
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if (rtnl_wilddump_request(rth, AF_UNSPEC, RTM_GETLINK) < 0) {
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bb_perror_msg_and_die("cannot send dump request");
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}
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if (rtnl_dump_filter(rth, ll_remember_index, &idxmap, NULL, NULL) < 0) {
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bb_error_msg_and_die("dump terminated");
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}
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return 0;
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}
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