projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
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 <[email protected]> | |
| 10 | */ | |
| 11 | ||
| 12 | #include <linux/config.h> | |
| 13 | #include <linux/module.h> | |
| 14 | #include <linux/types.h> | |
| 15 | #include <linux/kernel.h> | |
| 16 | #include <linux/skbuff.h> | |
| 17 | #include <linux/tc_ematch/tc_em_cmp.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 = *ptr << 8; | |
| 42 | val |= *(ptr+1); | |
| 43 | ||
| 44 | if (cmp_needs_transformation(cmp)) | |
| 45 | val = be16_to_cpu(val); | |
| 46 | break; | |
| 47 | ||
| 48 | case TCF_EM_ALIGN_U32: | |
| 49 | /* Worth checking boundries? The branching seems | |
| 50 | * to get worse. Visit again. */ | |
| 51 | val = *ptr << 24; | |
| 52 | val |= *(ptr+1) << 16; | |
| 53 | val |= *(ptr+2) << 8; | |
| 54 | val |= *(ptr+3); | |
| 55 | ||
| 56 | if (cmp_needs_transformation(cmp)) | |
| 57 | val = be32_to_cpu(val); | |
| 58 | break; | |
| 59 | ||
| 60 | default: | |
| 61 | return 0; | |
| 62 | } | |
| 63 | ||
| 64 | if (cmp->mask) | |
| 65 | val &= cmp->mask; | |
| 66 | ||
| 67 | switch (cmp->opnd) { | |
| 68 | case TCF_EM_OPND_EQ: | |
| 69 | return val == cmp->val; | |
| 70 | case TCF_EM_OPND_LT: | |
| 71 | return val < cmp->val; | |
| 72 | case TCF_EM_OPND_GT: | |
| 73 | return val > cmp->val; | |
| 74 | } | |
| 75 | ||
| 76 | return 0; | |
| 77 | } | |
| 78 | ||
| 79 | static struct tcf_ematch_ops em_cmp_ops = { | |
| 80 | .kind = TCF_EM_CMP, | |
| 81 | .datalen = sizeof(struct tcf_em_cmp), | |
| 82 | .match = em_cmp_match, | |
| 83 | .owner = THIS_MODULE, | |
| 84 | .link = LIST_HEAD_INIT(em_cmp_ops.link) | |
| 85 | }; | |
| 86 | ||
| 87 | static int __init init_em_cmp(void) | |
| 88 | { | |
| 89 | return tcf_em_register(&em_cmp_ops); | |
| 90 | } | |
| 91 | ||
| 92 | static void __exit exit_em_cmp(void) | |
| 93 | { | |
| 94 | tcf_em_unregister(&em_cmp_ops); | |
| 95 | } | |
| 96 | ||
| 97 | MODULE_LICENSE("GPL"); | |
| 98 | ||
| 99 | module_init(init_em_cmp); | |
| 100 | module_exit(exit_em_cmp); | |
| 101 |