1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * 802_3 |
4 | * |
5 | * Author: |
6 | * Chris Vitale csv@bluetail.com |
7 | * |
8 | * May 2003 |
9 | * |
10 | */ |
11 | #include <linux/module.h> |
12 | #include <linux/netfilter/x_tables.h> |
13 | #include <linux/netfilter_bridge/ebtables.h> |
14 | #include <linux/skbuff.h> |
15 | #include <uapi/linux/netfilter_bridge/ebt_802_3.h> |
16 | |
17 | static struct ebt_802_3_hdr *ebt_802_3_hdr(const struct sk_buff *skb) |
18 | { |
19 | return (struct ebt_802_3_hdr *)skb_mac_header(skb); |
20 | } |
21 | |
22 | static bool |
23 | ebt_802_3_mt(const struct sk_buff *skb, struct xt_action_param *par) |
24 | { |
25 | const struct ebt_802_3_info *info = par->matchinfo; |
26 | const struct ebt_802_3_hdr *hdr = ebt_802_3_hdr(skb); |
27 | __be16 type = hdr->llc.ui.ctrl & IS_UI ? hdr->llc.ui.type : hdr->llc.ni.type; |
28 | |
29 | if (info->bitmask & EBT_802_3_SAP) { |
30 | if (NF_INVF(info, EBT_802_3_SAP, info->sap != hdr->llc.ui.ssap)) |
31 | return false; |
32 | if (NF_INVF(info, EBT_802_3_SAP, info->sap != hdr->llc.ui.dsap)) |
33 | return false; |
34 | } |
35 | |
36 | if (info->bitmask & EBT_802_3_TYPE) { |
37 | if (!(hdr->llc.ui.dsap == CHECK_TYPE && hdr->llc.ui.ssap == CHECK_TYPE)) |
38 | return false; |
39 | if (NF_INVF(info, EBT_802_3_TYPE, info->type != type)) |
40 | return false; |
41 | } |
42 | |
43 | return true; |
44 | } |
45 | |
46 | static int ebt_802_3_mt_check(const struct xt_mtchk_param *par) |
47 | { |
48 | const struct ebt_802_3_info *info = par->matchinfo; |
49 | |
50 | if (info->bitmask & ~EBT_802_3_MASK || info->invflags & ~EBT_802_3_MASK) |
51 | return -EINVAL; |
52 | |
53 | return 0; |
54 | } |
55 | |
56 | static struct xt_match ebt_802_3_mt_reg __read_mostly = { |
57 | .name = "802_3" , |
58 | .revision = 0, |
59 | .family = NFPROTO_BRIDGE, |
60 | .match = ebt_802_3_mt, |
61 | .checkentry = ebt_802_3_mt_check, |
62 | .matchsize = sizeof(struct ebt_802_3_info), |
63 | .me = THIS_MODULE, |
64 | }; |
65 | |
66 | static int __init ebt_802_3_init(void) |
67 | { |
68 | return xt_register_match(target: &ebt_802_3_mt_reg); |
69 | } |
70 | |
71 | static void __exit ebt_802_3_fini(void) |
72 | { |
73 | xt_unregister_match(target: &ebt_802_3_mt_reg); |
74 | } |
75 | |
76 | module_init(ebt_802_3_init); |
77 | module_exit(ebt_802_3_fini); |
78 | MODULE_DESCRIPTION("Ebtables: DSAP/SSAP field and SNAP type matching" ); |
79 | MODULE_LICENSE("GPL" ); |
80 | |