1 /* ebt_arp
2 *
3 * Authors:
4 * Bart De Schuymer <bdschuym@pandora.be>
5 * Tim Gardner <timg@tpi.com>
6 *
7 * April, 2002
8 */
9
10 #include <stdio.h>
11 #include <string.h>
12 #include <stdlib.h>
13 #include <xtables.h>
14 #include <netinet/ether.h>
15
16 #include <xtables.h>
17 #include <net/if_arp.h>
18 #include <linux/netfilter_bridge/ebt_arp.h>
19 #include "iptables/nft.h"
20 #include "iptables/nft-bridge.h"
21
22 /* values must correspond with EBT_ARP_* bit positions */
23 enum {
24 O_OPCODE = 0,
25 O_HTYPE,
26 O_PTYPE,
27 O_SRC_IP,
28 O_DST_IP,
29 O_SRC_MAC,
30 O_DST_MAC,
31 O_GRAT,
32 };
33
34 static const struct xt_option_entry brarp_opts[] = {
35 #define ENTRY(n, i, t) { .name = n, .id = i, .type = t, .flags = XTOPT_INVERT }
36 ENTRY("arp-opcode", O_OPCODE, XTTYPE_STRING),
37 ENTRY("arp-op", O_OPCODE, XTTYPE_STRING),
38 ENTRY("arp-htype", O_HTYPE, XTTYPE_STRING),
39 ENTRY("arp-ptype", O_PTYPE, XTTYPE_STRING),
40 ENTRY("arp-ip-src", O_SRC_IP, XTTYPE_HOSTMASK),
41 ENTRY("arp-ip-dst", O_DST_IP, XTTYPE_HOSTMASK),
42 ENTRY("arp-mac-src", O_SRC_MAC, XTTYPE_ETHERMACMASK),
43 ENTRY("arp-mac-dst", O_DST_MAC, XTTYPE_ETHERMACMASK),
44 ENTRY("arp-gratuitous", O_GRAT, XTTYPE_NONE),
45 #undef ENTRY
46 XTOPT_TABLEEND
47 };
48
49 /* a few names */
50 static char *opcodes[] =
51 {
52 "Request",
53 "Reply",
54 "Request_Reverse",
55 "Reply_Reverse",
56 "DRARP_Request",
57 "DRARP_Reply",
58 "DRARP_Error",
59 "InARP_Request",
60 "ARP_NAK",
61 };
62
brarp_print_help(void)63 static void brarp_print_help(void)
64 {
65 int i;
66
67 printf(
68 "arp options:\n"
69 "[!] --arp-opcode opcode : ARP opcode (integer or string)\n"
70 "[!] --arp-htype type : ARP hardware type (integer or string)\n"
71 "[!] --arp-ptype type : ARP protocol type (hexadecimal or string)\n"
72 "[!] --arp-ip-src address[/mask]: ARP IP source specification\n"
73 "[!] --arp-ip-dst address[/mask]: ARP IP target specification\n"
74 "[!] --arp-mac-src address[/mask]: ARP MAC source specification\n"
75 "[!] --arp-mac-dst address[/mask]: ARP MAC target specification\n"
76 "[!] --arp-gratuitous : ARP gratuitous packet\n"
77 " opcode strings: \n");
78 for (i = 0; i < ARRAY_SIZE(opcodes); i++)
79 printf(" %d = %s\n", i + 1, opcodes[i]);
80 printf(
81 " hardware type string: 1 = Ethernet\n"
82 " protocol type string: see "XT_PATH_ETHERTYPES"\n");
83 }
84
brarp_parse(struct xt_option_call * cb)85 static void brarp_parse(struct xt_option_call *cb)
86 {
87 struct ebt_arp_info *arpinfo = cb->data;
88 struct xt_ethertypeent *ent;
89 long int i;
90 char *end;
91
92
93 xtables_option_parse(cb);
94
95 arpinfo->bitmask |= 1 << cb->entry->id;
96 if (cb->invert)
97 arpinfo->invflags |= 1 << cb->entry->id;
98
99 switch (cb->entry->id) {
100 case O_OPCODE:
101 i = strtol(cb->arg, &end, 10);
102 if (i < 0 || i >= (0x1 << 16) || *end !='\0') {
103 for (i = 0; i < ARRAY_SIZE(opcodes); i++)
104 if (!strcasecmp(opcodes[i], cb->arg))
105 break;
106 if (i == ARRAY_SIZE(opcodes))
107 xtables_error(PARAMETER_PROBLEM,
108 "Problem with specified ARP opcode");
109 i++;
110 }
111 arpinfo->opcode = htons(i);
112 break;
113 case O_HTYPE:
114 i = strtol(cb->arg, &end, 10);
115 if (i < 0 || i >= (0x1 << 16) || *end !='\0') {
116 if (!strcasecmp("Ethernet", cb->arg))
117 i = 1;
118 else
119 xtables_error(PARAMETER_PROBLEM,
120 "Problem with specified ARP hardware type");
121 }
122 arpinfo->htype = htons(i);
123 break;
124 case O_PTYPE:
125 i = strtol(cb->arg, &end, 16);
126 if (i >= 0 && i < (0x1 << 16) && *end == '\0') {
127 arpinfo->ptype = htons(i);
128 break;
129 }
130 ent = xtables_getethertypebyname(cb->arg);
131 if (!ent)
132 xtables_error(PARAMETER_PROBLEM,
133 "Problem with specified ARP protocol type");
134 arpinfo->ptype = htons(ent->e_ethertype);
135 break;
136 case O_SRC_IP:
137 arpinfo->saddr = cb->val.haddr.ip & cb->val.hmask.ip;
138 arpinfo->smsk = cb->val.hmask.ip;
139 break;
140 case O_DST_IP:
141 arpinfo->daddr = cb->val.haddr.ip & cb->val.hmask.ip;
142 arpinfo->dmsk = cb->val.hmask.ip;
143 break;
144 case O_SRC_MAC:
145 memcpy(arpinfo->smaddr, cb->val.ethermac, ETH_ALEN);
146 memcpy(arpinfo->smmsk, cb->val.ethermacmask, ETH_ALEN);
147 break;
148 case O_DST_MAC:
149 memcpy(arpinfo->dmaddr, cb->val.ethermac, ETH_ALEN);
150 memcpy(arpinfo->dmmsk, cb->val.ethermacmask, ETH_ALEN);
151 break;
152 }
153 }
154
brarp_print(const void * ip,const struct xt_entry_match * match,int numeric)155 static void brarp_print(const void *ip, const struct xt_entry_match *match, int numeric)
156 {
157 const struct ebt_arp_info *arpinfo = (struct ebt_arp_info *)match->data;
158
159 if (arpinfo->bitmask & EBT_ARP_OPCODE) {
160 int opcode = ntohs(arpinfo->opcode);
161
162 if (arpinfo->invflags & EBT_ARP_OPCODE)
163 printf("! ");
164 printf("--arp-op ");
165 if (opcode > 0 && opcode <= ARRAY_SIZE(opcodes))
166 printf("%s ", opcodes[opcode - 1]);
167 else
168 printf("%d ", opcode);
169 }
170 if (arpinfo->bitmask & EBT_ARP_HTYPE) {
171 if (arpinfo->invflags & EBT_ARP_HTYPE)
172 printf("! ");
173 printf("--arp-htype %d ", ntohs(arpinfo->htype));
174 }
175 if (arpinfo->bitmask & EBT_ARP_PTYPE) {
176 if (arpinfo->invflags & EBT_ARP_PTYPE)
177 printf("! ");
178 printf("--arp-ptype 0x%x ", ntohs(arpinfo->ptype));
179 }
180 if (arpinfo->bitmask & EBT_ARP_SRC_IP) {
181 if (arpinfo->invflags & EBT_ARP_SRC_IP)
182 printf("! ");
183 printf("--arp-ip-src %s%s ",
184 xtables_ipaddr_to_numeric((void *)&arpinfo->saddr),
185 xtables_ipmask_to_numeric((void *)&arpinfo->smsk));
186 }
187 if (arpinfo->bitmask & EBT_ARP_DST_IP) {
188 if (arpinfo->invflags & EBT_ARP_DST_IP)
189 printf("! ");
190 printf("--arp-ip-dst %s%s ",
191 xtables_ipaddr_to_numeric((void *)&arpinfo->daddr),
192 xtables_ipmask_to_numeric((void *)&arpinfo->dmsk));
193 }
194 if (arpinfo->bitmask & EBT_ARP_SRC_MAC) {
195 if (arpinfo->invflags & EBT_ARP_SRC_MAC)
196 printf("! ");
197 printf("--arp-mac-src ");
198 xtables_print_mac_and_mask(arpinfo->smaddr, arpinfo->smmsk);
199 printf(" ");
200 }
201 if (arpinfo->bitmask & EBT_ARP_DST_MAC) {
202 if (arpinfo->invflags & EBT_ARP_DST_MAC)
203 printf("! ");
204 printf("--arp-mac-dst ");
205 xtables_print_mac_and_mask(arpinfo->dmaddr, arpinfo->dmmsk);
206 printf(" ");
207 }
208 if (arpinfo->bitmask & EBT_ARP_GRAT) {
209 if (arpinfo->invflags & EBT_ARP_GRAT)
210 printf("! ");
211 printf("--arp-gratuitous ");
212 }
213 }
214
215 static struct xtables_match brarp_match = {
216 .name = "arp",
217 .version = XTABLES_VERSION,
218 .family = NFPROTO_BRIDGE,
219 .size = XT_ALIGN(sizeof(struct ebt_arp_info)),
220 .userspacesize = XT_ALIGN(sizeof(struct ebt_arp_info)),
221 .help = brarp_print_help,
222 .x6_parse = brarp_parse,
223 .print = brarp_print,
224 .x6_options = brarp_opts,
225 };
226
_init(void)227 void _init(void)
228 {
229 xtables_register_match(&brarp_match);
230 }
231