Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
[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 <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