Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * net/sched/em_cmp.c Simple packet data comparison ematch | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation; either version | |
7 | * 2 of the License, or (at your option) any later version. | |
8 | * | |
9 | * Authors: Thomas Graf <tgraf@suug.ch> | |
10 | */ | |
11 | ||
1da177e4 LT |
12 | #include <linux/module.h> |
13 | #include <linux/types.h> | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/skbuff.h> | |
16 | #include <linux/tc_ematch/tc_em_cmp.h> | |
17 | #include <net/pkt_cls.h> | |
18 | ||
19 | static inline int cmp_needs_transformation(struct tcf_em_cmp *cmp) | |
20 | { | |
21 | return unlikely(cmp->flags & TCF_EM_CMP_TRANS); | |
22 | } | |
23 | ||
24 | static int em_cmp_match(struct sk_buff *skb, struct tcf_ematch *em, | |
25 | struct tcf_pkt_info *info) | |
26 | { | |
27 | struct tcf_em_cmp *cmp = (struct tcf_em_cmp *) em->data; | |
28 | unsigned char *ptr = tcf_get_base_ptr(skb, cmp->layer) + cmp->off; | |
29 | u32 val = 0; | |
30 | ||
31 | if (!tcf_valid_offset(skb, ptr, cmp->align)) | |
32 | return 0; | |
33 | ||
34 | switch (cmp->align) { | |
35 | case TCF_EM_ALIGN_U8: | |
36 | val = *ptr; | |
37 | break; | |
38 | ||
39 | case TCF_EM_ALIGN_U16: | |
40 | val = *ptr << 8; | |
41 | val |= *(ptr+1); | |
42 | ||
43 | if (cmp_needs_transformation(cmp)) | |
44 | val = be16_to_cpu(val); | |
45 | break; | |
46 | ||
47 | case TCF_EM_ALIGN_U32: | |
48 | /* Worth checking boundries? The branching seems | |
49 | * to get worse. Visit again. */ | |
50 | val = *ptr << 24; | |
51 | val |= *(ptr+1) << 16; | |
52 | val |= *(ptr+2) << 8; | |
53 | val |= *(ptr+3); | |
54 | ||
55 | if (cmp_needs_transformation(cmp)) | |
56 | val = be32_to_cpu(val); | |
57 | break; | |
58 | ||
59 | default: | |
60 | return 0; | |
61 | } | |
62 | ||
63 | if (cmp->mask) | |
64 | val &= cmp->mask; | |
65 | ||
66 | switch (cmp->opnd) { | |
67 | case TCF_EM_OPND_EQ: | |
68 | return val == cmp->val; | |
69 | case TCF_EM_OPND_LT: | |
70 | return val < cmp->val; | |
71 | case TCF_EM_OPND_GT: | |
72 | return val > cmp->val; | |
73 | } | |
74 | ||
75 | return 0; | |
76 | } | |
77 | ||
78 | static struct tcf_ematch_ops em_cmp_ops = { | |
79 | .kind = TCF_EM_CMP, | |
80 | .datalen = sizeof(struct tcf_em_cmp), | |
81 | .match = em_cmp_match, | |
82 | .owner = THIS_MODULE, | |
83 | .link = LIST_HEAD_INIT(em_cmp_ops.link) | |
84 | }; | |
85 | ||
86 | static int __init init_em_cmp(void) | |
87 | { | |
88 | return tcf_em_register(&em_cmp_ops); | |
89 | } | |
90 | ||
91 | static void __exit exit_em_cmp(void) | |
92 | { | |
93 | tcf_em_unregister(&em_cmp_ops); | |
94 | } | |
95 | ||
96 | MODULE_LICENSE("GPL"); | |
97 | ||
98 | module_init(init_em_cmp); | |
99 | module_exit(exit_em_cmp); | |
100 |