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 000000000000..bf1f00f8b1bf
--- /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);
+