slirp/arp_table.c

   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 "qemu/osdep.h"
  26 #include "slirp.h"
  27
  28 void arp_table_add(Slirp *slirp, uint32_t ip_addr, uint8_t ethaddr[ETH_ALEN])
  29 {
  30     const uint32_t broadcast_addr =
  31         ~slirp->vnetwork_mask.s_addr | slirp->vnetwork_addr.s_addr;
  32     ArpTable *arptbl = &slirp->arp_table;
  33     int i;
  34
  35     DEBUG_CALL("arp_table_add");
  36     DEBUG_ARG("ip = %s", inet_ntoa((struct in_addr){.s_addr = ip_addr}));
  37     DEBUG_ARGS((dfd, " hw addr = %02x:%02x:%02x:%02x:%02x:%02x\n",
  38                 ethaddr[0], ethaddr[1], ethaddr[2],
  39                 ethaddr[3], ethaddr[4], ethaddr[5]));
  40
  41     if (ip_addr == 0 || ip_addr == 0xffffffff || ip_addr == broadcast_addr) {
  42         /* Do not register broadcast addresses */
  43         return;
  44     }
  45
  46     /* Search for an entry */
  47     for (i = 0; i < ARP_TABLE_SIZE; i++) {
  48         if (arptbl->table[i].ar_sip == ip_addr) {
  49             /* Update the entry */
  50             memcpy(arptbl->table[i].ar_sha, ethaddr, ETH_ALEN);
  51             return;
  52         }
  53     }
  54
  55     /* No entry found, create a new one */
  56     arptbl->table[arptbl->next_victim].ar_sip = ip_addr;
  57     memcpy(arptbl->table[arptbl->next_victim].ar_sha,  ethaddr, ETH_ALEN);
  58     arptbl->next_victim = (arptbl->next_victim + 1) % ARP_TABLE_SIZE;
  59 }
  60
  61 bool arp_table_search(Slirp *slirp, uint32_t ip_addr,
  62                       uint8_t out_ethaddr[ETH_ALEN])
  63 {
  64     const uint32_t broadcast_addr =
  65         ~slirp->vnetwork_mask.s_addr | slirp->vnetwork_addr.s_addr;
  66     ArpTable *arptbl = &slirp->arp_table;
  67     int i;
  68
  69     DEBUG_CALL("arp_table_search");
  70     DEBUG_ARG("ip = %s", inet_ntoa((struct in_addr){.s_addr = ip_addr}));
  71
  72     /* If broadcast address */
  73     if (ip_addr == 0xffffffff || ip_addr == broadcast_addr) {
  74         /* return Ethernet broadcast address */
  75         memset(out_ethaddr, 0xff, ETH_ALEN);
  76         return 1;
  77     }
  78
  79     for (i = 0; i < ARP_TABLE_SIZE; i++) {
  80         if (arptbl->table[i].ar_sip == ip_addr) {
  81             memcpy(out_ethaddr, arptbl->table[i].ar_sha,  ETH_ALEN);
  82             DEBUG_ARGS((dfd, " found hw addr = %02x:%02x:%02x:%02x:%02x:%02x\n",
  83                         out_ethaddr[0], out_ethaddr[1], out_ethaddr[2],
  84                         out_ethaddr[3], out_ethaddr[4], out_ethaddr[5]));
  85             return 1;
  86         }
  87     }
  88
  89     return 0;
  90 }