LXR qemu/slirp/arp

   1/*
   2 * ARP table
   3 *
   4 * Copyright (c) 2011 AdaCore
   5 *
   6 * Permission is hereby granted, free of charge, to any person obtaining a copy
   7 * of this software and associated documentation files (the "Software"), to deal
   8 * in the Software without restriction, including without limitation the rights
   9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10 * copies of the Software, and to permit persons to whom the Software is
  11 * furnished to do so, subject to the following conditions:
  12 *
  13 * The above copyright notice and this permission notice shall be included in
  14 * all copies or substantial portions of the Software.
  15 *
  16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22 * THE SOFTWARE.
  23 */
  24
  25#include "slirp.h"
  26
  27void arp_table_add(Slirp *slirp, uint32_t ip_addr, uint8_t ethaddr[ETH_ALEN])
  28{
  29    const uint32_t broadcast_addr =
  30        ~slirp->vnetwork_mask.s_addr | slirp->vnetwork_addr.s_addr;
  31    ArpTable *arptbl = &slirp->arp_table;
  32    int i;
  33
  34    DEBUG_CALL("arp_table_add");
  35    DEBUG_ARG("ip = 0x%x", ip_addr);
  36    DEBUG_ARGS((dfd, " hw addr = %02x:%02x:%02x:%02x:%02x:%02x\n",
  37                ethaddr[0], ethaddr[1], ethaddr[2],
  38                ethaddr[3], ethaddr[4], ethaddr[5]));
  39
  40    /* Check 0.0.0.0/8 invalid source-only addresses */
  41    if ((ip_addr & htonl(~(0xf << 28))) == 0) {
  42        return;
  43    }
  44
  45    if (ip_addr == 0xffffffff || ip_addr == broadcast_addr) {
  46        /* Do not register broadcast addresses */
  47        return;
  48    }
  49
  50    /* Search for an entry */
  51    for (i = 0; i < ARP_TABLE_SIZE; i++) {
  52        if (arptbl->table[i].ar_sip == ip_addr) {
  53            /* Update the entry */
  54            memcpy(arptbl->table[i].ar_sha, ethaddr, ETH_ALEN);
  55            return;
  56        }
  57    }
  58
  59    /* No entry found, create a new one */
  60    arptbl->table[arptbl->next_victim].ar_sip = ip_addr;
  61    memcpy(arptbl->table[arptbl->next_victim].ar_sha,  ethaddr, ETH_ALEN);
  62    arptbl->next_victim = (arptbl->next_victim + 1) % ARP_TABLE_SIZE;
  63}
  64
  65bool arp_table_search(Slirp *slirp, uint32_t ip_addr,
  66                      uint8_t out_ethaddr[ETH_ALEN])
  67{
  68    const uint32_t broadcast_addr =
  69        ~slirp->vnetwork_mask.s_addr | slirp->vnetwork_addr.s_addr;
  70    ArpTable *arptbl = &slirp->arp_table;
  71    int i;
  72
  73    DEBUG_CALL("arp_table_search");
  74    DEBUG_ARG("ip = 0x%x", ip_addr);
  75
  76    /* Check 0.0.0.0/8 invalid source-only addresses */
  77    assert((ip_addr & htonl(~(0xf << 28))) != 0);
  78
  79    /* If broadcast address */
  80    if (ip_addr == 0xffffffff || ip_addr == broadcast_addr) {
  81        /* return Ethernet broadcast address */
  82        memset(out_ethaddr, 0xff, ETH_ALEN);
  83        return 1;
  84    }
  85
  86    for (i = 0; i < ARP_TABLE_SIZE; i++) {
  87        if (arptbl->table[i].ar_sip == ip_addr) {
  88            memcpy(out_ethaddr, arptbl->table[i].ar_sha,  ETH_ALEN);
  89            DEBUG_ARGS((dfd, " found hw addr = %02x:%02x:%02x:%02x:%02x:%02x\n",
  90                        out_ethaddr[0], out_ethaddr[1], out_ethaddr[2],
  91                        out_ethaddr[3], out_ethaddr[4], out_ethaddr[5]));
  92            return 1;
  93        }
  94    }
  95
  96    return 0;
  97}
  98