1 | // SPDX-License-Identifier: GPL-2.0-or-later |
---|---|
2 | /* |
3 | * net/sched/em_cmp.c Simple packet data comparison ematch |
4 | * |
5 | * Authors: Thomas Graf <tgraf@suug.ch> |
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 <asm/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, layer: cmp->layer) + cmp->off; |
26 | u32 val = 0; |
27 | |
28 | if (!tcf_valid_offset(skb, ptr, len: cmp->align)) |
29 | return 0; |
30 | |
31 | switch (cmp->align) { |
32 | case TCF_EM_ALIGN_U8: |
33 | val = *ptr; |
34 | break; |
35 | |
36 | case TCF_EM_ALIGN_U16: |
37 | val = get_unaligned_be16(p: ptr); |
38 | |
39 | if (cmp_needs_transformation(cmp)) |
40 | val = be16_to_cpu(val); |
41 | break; |
42 | |
43 | case TCF_EM_ALIGN_U32: |
44 | /* Worth checking boundaries? The branching seems |
45 | * to get worse. Visit again. |
46 | */ |
47 | val = get_unaligned_be32(p: ptr); |
48 | |
49 | if (cmp_needs_transformation(cmp)) |
50 | val = be32_to_cpu(val); |
51 | break; |
52 | |
53 | default: |
54 | return 0; |
55 | } |
56 | |
57 | if (cmp->mask) |
58 | val &= cmp->mask; |
59 | |
60 | switch (cmp->opnd) { |
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; |
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 | |
85 | static void __exit exit_em_cmp(void) |
86 | { |
87 | tcf_em_unregister(&em_cmp_ops); |
88 | } |
89 | |
90 | MODULE_DESCRIPTION("ematch classifier for basic data types(8/16/32 bit) against skb data"); |
91 | MODULE_LICENSE("GPL"); |
92 | |
93 | module_init(init_em_cmp); |
94 | module_exit(exit_em_cmp); |
95 | |
96 | MODULE_ALIAS_TCF_EMATCH(TCF_EM_CMP); |
97 |