1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-or-later
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * net/sched/em_cmp.c Simple packet data comparison ematch
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Authors: Thomas Graf <tgraf@suug.ch>
6*4882a593Smuzhiyun */
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun #include <linux/module.h>
9*4882a593Smuzhiyun #include <linux/types.h>
10*4882a593Smuzhiyun #include <linux/kernel.h>
11*4882a593Smuzhiyun #include <linux/skbuff.h>
12*4882a593Smuzhiyun #include <linux/tc_ematch/tc_em_cmp.h>
13*4882a593Smuzhiyun #include <asm/unaligned.h>
14*4882a593Smuzhiyun #include <net/pkt_cls.h>
15*4882a593Smuzhiyun
cmp_needs_transformation(struct tcf_em_cmp * cmp)16*4882a593Smuzhiyun static inline int cmp_needs_transformation(struct tcf_em_cmp *cmp)
17*4882a593Smuzhiyun {
18*4882a593Smuzhiyun return unlikely(cmp->flags & TCF_EM_CMP_TRANS);
19*4882a593Smuzhiyun }
20*4882a593Smuzhiyun
em_cmp_match(struct sk_buff * skb,struct tcf_ematch * em,struct tcf_pkt_info * info)21*4882a593Smuzhiyun static int em_cmp_match(struct sk_buff *skb, struct tcf_ematch *em,
22*4882a593Smuzhiyun struct tcf_pkt_info *info)
23*4882a593Smuzhiyun {
24*4882a593Smuzhiyun struct tcf_em_cmp *cmp = (struct tcf_em_cmp *) em->data;
25*4882a593Smuzhiyun unsigned char *ptr = tcf_get_base_ptr(skb, cmp->layer) + cmp->off;
26*4882a593Smuzhiyun u32 val = 0;
27*4882a593Smuzhiyun
28*4882a593Smuzhiyun if (!tcf_valid_offset(skb, ptr, cmp->align))
29*4882a593Smuzhiyun return 0;
30*4882a593Smuzhiyun
31*4882a593Smuzhiyun switch (cmp->align) {
32*4882a593Smuzhiyun case TCF_EM_ALIGN_U8:
33*4882a593Smuzhiyun val = *ptr;
34*4882a593Smuzhiyun break;
35*4882a593Smuzhiyun
36*4882a593Smuzhiyun case TCF_EM_ALIGN_U16:
37*4882a593Smuzhiyun val = get_unaligned_be16(ptr);
38*4882a593Smuzhiyun
39*4882a593Smuzhiyun if (cmp_needs_transformation(cmp))
40*4882a593Smuzhiyun val = be16_to_cpu(val);
41*4882a593Smuzhiyun break;
42*4882a593Smuzhiyun
43*4882a593Smuzhiyun case TCF_EM_ALIGN_U32:
44*4882a593Smuzhiyun /* Worth checking boundries? The branching seems
45*4882a593Smuzhiyun * to get worse. Visit again.
46*4882a593Smuzhiyun */
47*4882a593Smuzhiyun val = get_unaligned_be32(ptr);
48*4882a593Smuzhiyun
49*4882a593Smuzhiyun if (cmp_needs_transformation(cmp))
50*4882a593Smuzhiyun val = be32_to_cpu(val);
51*4882a593Smuzhiyun break;
52*4882a593Smuzhiyun
53*4882a593Smuzhiyun default:
54*4882a593Smuzhiyun return 0;
55*4882a593Smuzhiyun }
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun if (cmp->mask)
58*4882a593Smuzhiyun val &= cmp->mask;
59*4882a593Smuzhiyun
60*4882a593Smuzhiyun switch (cmp->opnd) {
61*4882a593Smuzhiyun case TCF_EM_OPND_EQ:
62*4882a593Smuzhiyun return val == cmp->val;
63*4882a593Smuzhiyun case TCF_EM_OPND_LT:
64*4882a593Smuzhiyun return val < cmp->val;
65*4882a593Smuzhiyun case TCF_EM_OPND_GT:
66*4882a593Smuzhiyun return val > cmp->val;
67*4882a593Smuzhiyun }
68*4882a593Smuzhiyun
69*4882a593Smuzhiyun return 0;
70*4882a593Smuzhiyun }
71*4882a593Smuzhiyun
72*4882a593Smuzhiyun static struct tcf_ematch_ops em_cmp_ops = {
73*4882a593Smuzhiyun .kind = TCF_EM_CMP,
74*4882a593Smuzhiyun .datalen = sizeof(struct tcf_em_cmp),
75*4882a593Smuzhiyun .match = em_cmp_match,
76*4882a593Smuzhiyun .owner = THIS_MODULE,
77*4882a593Smuzhiyun .link = LIST_HEAD_INIT(em_cmp_ops.link)
78*4882a593Smuzhiyun };
79*4882a593Smuzhiyun
init_em_cmp(void)80*4882a593Smuzhiyun static int __init init_em_cmp(void)
81*4882a593Smuzhiyun {
82*4882a593Smuzhiyun return tcf_em_register(&em_cmp_ops);
83*4882a593Smuzhiyun }
84*4882a593Smuzhiyun
exit_em_cmp(void)85*4882a593Smuzhiyun static void __exit exit_em_cmp(void)
86*4882a593Smuzhiyun {
87*4882a593Smuzhiyun tcf_em_unregister(&em_cmp_ops);
88*4882a593Smuzhiyun }
89*4882a593Smuzhiyun
90*4882a593Smuzhiyun MODULE_LICENSE("GPL");
91*4882a593Smuzhiyun
92*4882a593Smuzhiyun module_init(init_em_cmp);
93*4882a593Smuzhiyun module_exit(exit_em_cmp);
94*4882a593Smuzhiyun
95*4882a593Smuzhiyun MODULE_ALIAS_TCF_EMATCH(TCF_EM_CMP);
96