Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wirel...
[linux-2.6] / net / sched / em_cmp.c
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
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 <asm/unaligned.h>
18 #include <net/pkt_cls.h>
19
20 static inline int cmp_needs_transformation(struct tcf_em_cmp *cmp)
21 {
22         return unlikely(cmp->flags & TCF_EM_CMP_TRANS);
23 }
24
25 static int em_cmp_match(struct sk_buff *skb, struct tcf_ematch *em,
26                         struct tcf_pkt_info *info)
27 {
28         struct tcf_em_cmp *cmp = (struct tcf_em_cmp *) em->data;
29         unsigned char *ptr = tcf_get_base_ptr(skb, cmp->layer) + cmp->off;
30         u32 val = 0;
31
32         if (!tcf_valid_offset(skb, ptr, cmp->align))
33                 return 0;
34
35         switch (cmp->align) {
36                 case TCF_EM_ALIGN_U8:
37                         val = *ptr;
38                         break;
39
40                 case TCF_EM_ALIGN_U16:
41                         val = get_unaligned_be16(ptr);
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 = get_unaligned_be32(ptr);
51
52                         if (cmp_needs_transformation(cmp))
53                                 val = be32_to_cpu(val);
54                         break;
55
56                 default:
57                         return 0;
58         }
59
60         if (cmp->mask)
61                 val &= cmp->mask;
62
63         switch (cmp->opnd) {
64                 case TCF_EM_OPND_EQ:
65                         return val == cmp->val;
66                 case TCF_EM_OPND_LT:
67                         return val < cmp->val;
68                 case TCF_EM_OPND_GT:
69                         return val > cmp->val;
70         }
71
72         return 0;
73 }
74
75 static struct tcf_ematch_ops em_cmp_ops = {
76         .kind     = TCF_EM_CMP,
77         .datalen  = sizeof(struct tcf_em_cmp),
78         .match    = em_cmp_match,
79         .owner    = THIS_MODULE,
80         .link     = LIST_HEAD_INIT(em_cmp_ops.link)
81 };
82
83 static int __init init_em_cmp(void)
84 {
85         return tcf_em_register(&em_cmp_ops);
86 }
87
88 static void __exit exit_em_cmp(void)
89 {
90         tcf_em_unregister(&em_cmp_ops);
91 }
92
93 MODULE_LICENSE("GPL");
94
95 module_init(init_em_cmp);
96 module_exit(exit_em_cmp);
97
98 MODULE_ALIAS_TCF_EMATCH(TCF_EM_CMP);