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