| 1 | |
| 2 | |
| 3 | * net/sched/em_cmp.c Simple packet data comparison ematch
|
| 4 | *
|
| 5 | * Authors: Thomas Graf <[email protected]>
|
| 6 |
|
| 7 |
|
| 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>
|
| 13 | #include <linux/unaligned.h>
|
| 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);
|
| 26 | u32 val = 0;
|
| 27 |
|
| 28 | if (!ptr)
|
| 29 | return 0;
|
| 30 | ptr += cmp->off;
|
| 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 = get_unaligned_be16(ptr);
|
| 41 |
|
| 42 | if (cmp_needs_transformation(cmp))
|
| 43 | val = be16_to_cpu(val);
|
| 44 | break;
|
| 45 |
|
| 46 | case TCF_EM_ALIGN_U32:
|
| 47 | |
| 48 | * to get worse. Visit again.
|
| 49 |
|
| 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_DESCRIPTION("ematch classifier for basic data types(8/16/32 bit) against skb data");
|
| 94 | MODULE_LICENSE("GPL");
|
| 95 |
|
| 96 | module_init(init_em_cmp);
|
| 97 | module_exit(exit_em_cmp);
|
| 98 |
|
| 99 | MODULE_ALIAS_TCF_EMATCH(TCF_EM_CMP);
|