Commit | Line | Data |
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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4 LT |
2 | /* |
3 | * net/sched/em_cmp.c Simple packet data comparison ematch | |
4 | * | |
1da177e4 LT |
5 | * Authors: Thomas Graf <tgraf@suug.ch> |
6 | */ | |
7 | ||
1da177e4 LT |
8 | #include <linux/module.h> |
9 | #include <linux/types.h> | |
10 | #include <linux/kernel.h> | |
11 | #include <linux/skbuff.h> | |
12 | #include <linux/tc_ematch/tc_em_cmp.h> | |
d48abfec | 13 | #include <asm/unaligned.h> |
1da177e4 LT |
14 | #include <net/pkt_cls.h> |
15 | ||
16 | static inline int cmp_needs_transformation(struct tcf_em_cmp *cmp) | |
17 | { | |
18 | return unlikely(cmp->flags & TCF_EM_CMP_TRANS); | |
19 | } | |
20 | ||
21 | static int em_cmp_match(struct sk_buff *skb, struct tcf_ematch *em, | |
22 | struct tcf_pkt_info *info) | |
23 | { | |
24 | struct tcf_em_cmp *cmp = (struct tcf_em_cmp *) em->data; | |
25 | unsigned char *ptr = tcf_get_base_ptr(skb, cmp->layer) + cmp->off; | |
26 | u32 val = 0; | |
27 | ||
28 | if (!tcf_valid_offset(skb, ptr, cmp->align)) | |
29 | return 0; | |
30 | ||
31 | switch (cmp->align) { | |
cc7ec456 ED |
32 | case TCF_EM_ALIGN_U8: |
33 | val = *ptr; | |
34 | break; | |
1da177e4 | 35 | |
cc7ec456 ED |
36 | case TCF_EM_ALIGN_U16: |
37 | val = get_unaligned_be16(ptr); | |
1da177e4 | 38 | |
cc7ec456 ED |
39 | if (cmp_needs_transformation(cmp)) |
40 | val = be16_to_cpu(val); | |
41 | break; | |
1da177e4 | 42 | |
cc7ec456 | 43 | case TCF_EM_ALIGN_U32: |
e5a4b17d | 44 | /* Worth checking boundaries? The branching seems |
cc7ec456 ED |
45 | * to get worse. Visit again. |
46 | */ | |
47 | val = get_unaligned_be32(ptr); | |
1da177e4 | 48 | |
cc7ec456 ED |
49 | if (cmp_needs_transformation(cmp)) |
50 | val = be32_to_cpu(val); | |
51 | break; | |
1da177e4 | 52 | |
cc7ec456 ED |
53 | default: |
54 | return 0; | |
1da177e4 LT |
55 | } |
56 | ||
57 | if (cmp->mask) | |
58 | val &= cmp->mask; | |
59 | ||
60 | switch (cmp->opnd) { | |
cc7ec456 ED |
61 | case TCF_EM_OPND_EQ: |
62 | return val == cmp->val; | |
63 | case TCF_EM_OPND_LT: | |
64 | return val < cmp->val; | |
65 | case TCF_EM_OPND_GT: | |
66 | return val > cmp->val; | |
1da177e4 LT |
67 | } |
68 | ||
69 | return 0; | |
70 | } | |
71 | ||
72 | static struct tcf_ematch_ops em_cmp_ops = { | |
73 | .kind = TCF_EM_CMP, | |
74 | .datalen = sizeof(struct tcf_em_cmp), | |
75 | .match = em_cmp_match, | |
76 | .owner = THIS_MODULE, | |
77 | .link = LIST_HEAD_INIT(em_cmp_ops.link) | |
78 | }; | |
79 | ||
80 | static int __init init_em_cmp(void) | |
81 | { | |
82 | return tcf_em_register(&em_cmp_ops); | |
83 | } | |
84 | ||
10297b99 | 85 | static void __exit exit_em_cmp(void) |
1da177e4 LT |
86 | { |
87 | tcf_em_unregister(&em_cmp_ops); | |
88 | } | |
89 | ||
90 | MODULE_LICENSE("GPL"); | |
91 | ||
92 | module_init(init_em_cmp); | |
93 | module_exit(exit_em_cmp); | |
94 | ||
db3d99c0 | 95 | MODULE_ALIAS_TCF_EMATCH(TCF_EM_CMP); |