/* * net/sched/em_cmp.c Simple packet data comparison ematch * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * Authors: Thomas Graf <tgraf@suug.ch> */ #include <linux/config.h> #include <linux/module.h> #include <linux/types.h> #include <linux/kernel.h> #include <linux/skbuff.h> #include <linux/tc_ematch/tc_em_cmp.h> #include <net/pkt_cls.h> static inline int cmp_needs_transformation(struct tcf_em_cmp *cmp) { return unlikely(cmp->flags & TCF_EM_CMP_TRANS); } static int em_cmp_match(struct sk_buff *skb, struct tcf_ematch *em, struct tcf_pkt_info *info) { struct tcf_em_cmp *cmp = (struct tcf_em_cmp *) em->data; unsigned char *ptr = tcf_get_base_ptr(skb, cmp->layer) + cmp->off; u32 val = 0; if (!tcf_valid_offset(skb, ptr, cmp->align)) return 0; switch (cmp->align) { case TCF_EM_ALIGN_U8: val = *ptr; break; case TCF_EM_ALIGN_U16: val = *ptr << 8; val |= *(ptr+1); if (cmp_needs_transformation(cmp)) val = be16_to_cpu(val); break; case TCF_EM_ALIGN_U32: /* Worth checking boundries? The branching seems * to get worse. Visit again. */ val = *ptr << 24; val |= *(ptr+1) << 16; val |= *(ptr+2) << 8; val |= *(ptr+3); if (cmp_needs_transformation(cmp)) val = be32_to_cpu(val); break; default: return 0; } if (cmp->mask) val &= cmp->mask; switch (cmp->opnd) { case TCF_EM_OPND_EQ: return val == cmp->val; case TCF_EM_OPND_LT: return val < cmp->val; case TCF_EM_OPND_GT: return val > cmp->val; } return 0; } static struct tcf_ematch_ops em_cmp_ops = { .kind = TCF_EM_CMP, .datalen = sizeof(struct tcf_em_cmp), .match = em_cmp_match, .owner = THIS_MODULE, .link = LIST_HEAD_INIT(em_cmp_ops.link) }; static int __init init_em_cmp(void) { return tcf_em_register(&em_cmp_ops); } static void __exit exit_em_cmp(void) { tcf_em_unregister(&em_cmp_ops); } MODULE_LICENSE("GPL"); module_init(init_em_cmp); module_exit(exit_em_cmp);