slirp/src/ndp_table.c

   1 /* SPDX-License-Identifier: BSD-3-Clause */
   2 /*
   3  * Copyright (c) 2013
   4  * Guillaume Subiron, Yann Bordenave, Serigne Modou Wagne.
   5  */
   6
   7 #include "slirp.h"
   8
   9 void ndp_table_add(Slirp *slirp, struct in6_addr ip_addr,
  10                     uint8_t ethaddr[ETH_ALEN])
  11 {
  12     char addrstr[INET6_ADDRSTRLEN];
  13     NdpTable *ndp_table = &slirp->ndp_table;
  14     int i;
  15
  16     inet_ntop(AF_INET6, &(ip_addr), addrstr, INET6_ADDRSTRLEN);
  17
  18     DEBUG_CALL("ndp_table_add");
  19     DEBUG_ARG("ip = %s", addrstr);
  20     DEBUG_ARG("hw addr = %02x:%02x:%02x:%02x:%02x:%02x",
  21               ethaddr[0], ethaddr[1], ethaddr[2],
  22               ethaddr[3], ethaddr[4], ethaddr[5]);
  23
  24     if (IN6_IS_ADDR_MULTICAST(&ip_addr) || in6_zero(&ip_addr)) {
  25         /* Do not register multicast or unspecified addresses */
  26         DEBUG_CALL(" abort: do not register multicast or unspecified address");
  27         return;
  28     }
  29
  30     /* Search for an entry */
  31     for (i = 0; i < NDP_TABLE_SIZE; i++) {
  32         if (in6_equal(&ndp_table->table[i].ip_addr, &ip_addr)) {
  33             DEBUG_CALL(" already in table: update the entry");
  34             /* Update the entry */
  35             memcpy(ndp_table->table[i].eth_addr, ethaddr, ETH_ALEN);
  36             return;
  37         }
  38     }
  39
  40     /* No entry found, create a new one */
  41     DEBUG_CALL(" create new entry");
  42     ndp_table->table[ndp_table->next_victim].ip_addr = ip_addr;
  43     memcpy(ndp_table->table[ndp_table->next_victim].eth_addr,
  44             ethaddr, ETH_ALEN);
  45     ndp_table->next_victim = (ndp_table->next_victim + 1) % NDP_TABLE_SIZE;
  46 }
  47
  48 bool ndp_table_search(Slirp *slirp, struct in6_addr ip_addr,
  49                       uint8_t out_ethaddr[ETH_ALEN])
  50 {
  51     char addrstr[INET6_ADDRSTRLEN];
  52     NdpTable *ndp_table = &slirp->ndp_table;
  53     int i;
  54
  55     inet_ntop(AF_INET6, &(ip_addr), addrstr, INET6_ADDRSTRLEN);
  56
  57     DEBUG_CALL("ndp_table_search");
  58     DEBUG_ARG("ip = %s", addrstr);
  59
  60     assert(!in6_zero(&ip_addr));
  61
  62     /* Multicast address: fec0::abcd:efgh/8 -> 33:33:ab:cd:ef:gh */
  63     if (IN6_IS_ADDR_MULTICAST(&ip_addr)) {
  64         out_ethaddr[0] = 0x33; out_ethaddr[1] = 0x33;
  65         out_ethaddr[2] = ip_addr.s6_addr[12];
  66         out_ethaddr[3] = ip_addr.s6_addr[13];
  67         out_ethaddr[4] = ip_addr.s6_addr[14];
  68         out_ethaddr[5] = ip_addr.s6_addr[15];
  69         DEBUG_ARG("multicast addr = %02x:%02x:%02x:%02x:%02x:%02x",
  70                   out_ethaddr[0], out_ethaddr[1], out_ethaddr[2],
  71                   out_ethaddr[3], out_ethaddr[4], out_ethaddr[5]);
  72         return 1;
  73     }
  74
  75     for (i = 0; i < NDP_TABLE_SIZE; i++) {
  76         if (in6_equal(&ndp_table->table[i].ip_addr, &ip_addr)) {
  77             memcpy(out_ethaddr, ndp_table->table[i].eth_addr,  ETH_ALEN);
  78             DEBUG_ARG("found hw addr = %02x:%02x:%02x:%02x:%02x:%02x",
  79                       out_ethaddr[0], out_ethaddr[1], out_ethaddr[2],
  80                       out_ethaddr[3], out_ethaddr[4], out_ethaddr[5]);
  81             return 1;
  82         }
  83     }
  84
  85     DEBUG_CALL(" ip not found in table");
  86     return 0;
  87 }