1 files changed, 101 insertions, 0 deletions
diff --git a/net/sched/em_cmp.c b/net/sched/em_cmp.c
new file mode 100644
index 00000000000..bf1f00f8b1b
--- /dev/null
+++ b/net/sched/em_cmp.c
@@ -0,0 +1,101 @@
+/*
+ * 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);
+