[PATCH 6/6] PKT_SCHED: Basic classifier

[Thomas Graf <tgraf@suug.ch>]

The basic classifier is the most simple classifier one can think of,
it doesn't do anything on its own but to support extended matches and
actions. A basic classifier returns true if no ematches or actions
are configured and thus can also be used as a catch-all classifier.

Signed-off-by: Thomas Graf <tgraf@suug.ch>

diff -Nru linux-2.6.11-rc1-bk9.orig/include/linux/pkt_cls.h linux-2.6.11-rc1-bk9/include/linux/pkt_cls.h
--- linux-2.6.11-rc1-bk9.orig/include/linux/pkt_cls.h	2005-01-22 15:29:08.000000000 +0100
+++ linux-2.6.11-rc1-bk9/include/linux/pkt_cls.h	2005-01-22 15:55:17.000000000 +0100
@@ -319,6 +319,20 @@
 
 #define TCA_TCINDEX_MAX     (__TCA_TCINDEX_MAX - 1)
 
+/* Basic filter */
+
+enum
+{
+	TCA_BASIC_UNSPEC,
+	TCA_BASIC_CLASSID,
+	TCA_BASIC_EMATCHES,
+	TCA_BASIC_ACT,
+	TCA_BASIC_POLICE,
+	__TCA_BASIC_MAX
+};
+
+#define TCA_BASIC_MAX (__TCA_BASIC_MAX - 1)
+
 /* Extended Matches */
 
 struct tcf_ematch_tree_hdr
diff -Nru linux-2.6.11-rc1-bk9.orig/net/sched/Kconfig linux-2.6.11-rc1-bk9/net/sched/Kconfig
--- linux-2.6.11-rc1-bk9.orig/net/sched/Kconfig	2005-01-22 15:29:08.000000000 +0100
+++ linux-2.6.11-rc1-bk9/net/sched/Kconfig	2005-01-22 15:54:59.000000000 +0100
@@ -269,6 +269,16 @@
 	  Documentation and software is at
 	  <http://diffserv.sourceforge.net/>.
 
+config NET_CLS_BASIC
+	tristate "Basic classifier"
+	depends on NET_CLS
+	---help---
+	  Say Y here if you want to be able to classify packets using
+	  only extended matches and actions.
+
+	  To compile this code as a module, choose M here: the
+	  module will be called cls_basic.
+
 config NET_CLS_TCINDEX
 	tristate "TC index classifier"
 	depends on NET_CLS
diff -Nru linux-2.6.11-rc1-bk9.orig/net/sched/Makefile linux-2.6.11-rc1-bk9/net/sched/Makefile
--- linux-2.6.11-rc1-bk9.orig/net/sched/Makefile	2005-01-22 15:29:08.000000000 +0100
+++ linux-2.6.11-rc1-bk9/net/sched/Makefile	2005-01-22 15:54:59.000000000 +0100
@@ -33,6 +33,7 @@
 obj-$(CONFIG_NET_CLS_RSVP)	+= cls_rsvp.o
 obj-$(CONFIG_NET_CLS_TCINDEX)	+= cls_tcindex.o
 obj-$(CONFIG_NET_CLS_RSVP6)	+= cls_rsvp6.o
+obj-$(CONFIG_NET_CLS_BASIC)	+= cls_basic.o
 obj-$(CONFIG_NET_EMATCH)	+= ematch.o
 obj-$(CONFIG_NET_EMATCH_CMP)	+= em_cmp.o
 obj-$(CONFIG_NET_EMATCH_NBYTE)	+= em_nbyte.o
diff -Nru linux-2.6.11-rc1-bk9.orig/net/sched/cls_basic.c linux-2.6.11-rc1-bk9/net/sched/cls_basic.c
--- linux-2.6.11-rc1-bk9.orig/net/sched/cls_basic.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.11-rc1-bk9/net/sched/cls_basic.c	2005-01-22 16:12:49.000000000 +0100
@@ -0,0 +1,303 @@
+/*
+ * net/sched/cls_basic.c	Basic Packet Classifier.
+ *
+ *		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/sched.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/errno.h>
+#include <linux/rtnetlink.h>
+#include <linux/skbuff.h>
+#include <net/act_api.h>
+#include <net/pkt_cls.h>
+
+struct basic_head
+{
+	u32			hgenerator;
+	struct list_head	flist;
+};
+
+struct basic_filter
+{
+	u32			handle;
+	struct tcf_exts		exts;
+	struct tcf_ematch_tree	ematches;
+	struct tcf_result	res;
+	struct list_head	link;
+};
+
+static struct tcf_ext_map basic_ext_map = {
+	.action = TCA_BASIC_ACT,
+	.police = TCA_BASIC_POLICE
+};
+
+static int basic_classify(struct sk_buff *skb, struct tcf_proto *tp,
+			  struct tcf_result *res)
+{
+	int r;
+	struct basic_head *head = (struct basic_head *) tp->root;
+	struct basic_filter *f;
+
+	list_for_each_entry(f, &head->flist, link) {
+		if (!tcf_em_tree_match(skb, &f->ematches, NULL))
+			continue;
+		*res = f->res;
+		r = tcf_exts_exec(skb, &f->exts, res);
+		if (r < 0)
+			continue;
+		return r;
+	}
+	return -1;
+}
+
+static unsigned long basic_get(struct tcf_proto *tp, u32 handle)
+{
+	unsigned long l = 0UL;
+	struct basic_head *head = (struct basic_head *) tp->root;
+	struct basic_filter *f;
+
+	if (head == NULL)
+		return 0UL;
+
+	list_for_each_entry(f, &head->flist, link)
+		if (f->handle == handle)
+			l = (unsigned long) f;
+
+	return l;
+}
+
+static void basic_put(struct tcf_proto *tp, unsigned long f)
+{
+}
+
+static int basic_init(struct tcf_proto *tp)
+{
+	return 0;
+}
+
+static inline void basic_delete_filter(struct tcf_proto *tp,
+				       struct basic_filter *f)
+{
+	tcf_unbind_filter(tp, &f->res);
+	tcf_exts_destroy(tp, &f->exts);
+	tcf_em_tree_destroy(tp, &f->ematches);
+	kfree(f);
+}
+
+static void basic_destroy(struct tcf_proto *tp)
+{
+	struct basic_head *head = (struct basic_head *) xchg(&tp->root, NULL);
+	struct basic_filter *f, *n;
+	
+	list_for_each_entry_safe(f, n, &head->flist, link) {
+		list_del(&f->link);
+		basic_delete_filter(tp, f);
+	}
+}
+
+static int basic_delete(struct tcf_proto *tp, unsigned long arg)
+{
+	struct basic_head *head = (struct basic_head *) tp->root;
+	struct basic_filter *t, *f = (struct basic_filter *) arg;
+
+	list_for_each_entry(t, &head->flist, link)
+		if (t == f) {
+			tcf_tree_lock(tp);
+			list_del(&t->link);
+			tcf_tree_unlock(tp);
+			basic_delete_filter(tp, t);
+			return 0;
+		}
+
+	return -ENOENT;
+}
+
+static inline int basic_set_parms(struct tcf_proto *tp, struct basic_filter *f,
+				  unsigned long base, struct rtattr **tb,
+				  struct rtattr *est)
+{
+	int err = -EINVAL;
+	struct tcf_exts e;
+	struct tcf_ematch_tree t;
+
+	if (tb[TCA_BASIC_CLASSID-1])
+		if (RTA_PAYLOAD(tb[TCA_BASIC_CLASSID-1]) < sizeof(u32))
+			return err;
+
+	err = tcf_exts_validate(tp, tb, est, &e, &basic_ext_map);
+	if (err < 0)
+		return err;
+
+	err = tcf_em_tree_validate(tp, tb[TCA_BASIC_EMATCHES-1], &t);
+	if (err < 0)
+		goto errout;
+
+	if (tb[TCA_BASIC_CLASSID-1]) {
+		f->res.classid = *(u32*)RTA_DATA(tb[TCA_BASIC_CLASSID-1]);
+		tcf_bind_filter(tp, &f->res, base);
+	}
+
+	tcf_exts_change(tp, &f->exts, &e);
+	tcf_em_tree_change(tp, &f->ematches, &t);
+
+	return 0;
+errout:
+	tcf_exts_destroy(tp, &e);
+	return err;
+}
+
+static int basic_change(struct tcf_proto *tp, unsigned long base, u32 handle,
+		        struct rtattr **tca, unsigned long *arg)
+{
+	int err = -EINVAL;
+	struct basic_head *head = (struct basic_head *) tp->root;
+	struct rtattr *tb[TCA_BASIC_MAX];
+	struct basic_filter *f = (struct basic_filter *) *arg;
+
+	if (tca[TCA_OPTIONS-1] == NULL)
+		return -EINVAL;
+
+	if (rtattr_parse_nested(tb, TCA_BASIC_MAX, tca[TCA_OPTIONS-1]) < 0)
+		return -EINVAL;
+
+	if (f != NULL) {
+		if (handle && f->handle != handle)
+			return -EINVAL;
+		return basic_set_parms(tp, f, base, tb, tca[TCA_RATE-1]);
+	}
+
+	err = -ENOBUFS;
+	if (head == NULL) {
+		head = kmalloc(sizeof(*head), GFP_KERNEL);
+		if (head == NULL)
+			goto errout;
+
+		memset(head, 0, sizeof(*head));
+		INIT_LIST_HEAD(&head->flist);
+		tp->root = head;
+	}
+
+	f = kmalloc(sizeof(*f), GFP_KERNEL);
+	if (f == NULL)
+		goto errout;
+	memset(f, 0, sizeof(*f));
+
+	err = -EINVAL;
+	if (handle)
+		f->handle = handle;
+	else {
+		int i = 0x80000000;
+		do {
+			if (++head->hgenerator == 0x7FFFFFFF)
+				head->hgenerator = 1;
+		} while (--i > 0 && basic_get(tp, head->hgenerator));
+
+		if (i <= 0) {
+			printk(KERN_ERR "Insufficient number of handles\n");
+			goto errout;
+		}
+
+		f->handle = head->hgenerator;
+	}
+
+	err = basic_set_parms(tp, f, base, tb, tca[TCA_RATE-1]);
+	if (err < 0)
+		goto errout;
+
+	tcf_tree_lock(tp);
+	list_add(&f->link, &head->flist);
+	tcf_tree_unlock(tp);
+	*arg = (unsigned long) f;
+
+	return 0;
+errout:
+	if (*arg == 0UL && f)
+		kfree(f);
+
+	return err;
+}
+
+static void basic_walk(struct tcf_proto *tp, struct tcf_walker *arg)
+{
+	struct basic_head *head = (struct basic_head *) tp->root;
+	struct basic_filter *f;
+
+	list_for_each_entry(f, &head->flist, link) {
+		if (arg->count < arg->skip)
+			goto skip;
+
+		if (arg->fn(tp, (unsigned long) f, arg) < 0) {
+			arg->stop = 1;
+			break;
+		}
+skip:
+		arg->count++;
+	}
+}
+
+static int basic_dump(struct tcf_proto *tp, unsigned long fh,
+		      struct sk_buff *skb, struct tcmsg *t)
+{
+	struct basic_filter *f = (struct basic_filter *) fh;
+	unsigned char *b = skb->tail;
+	struct rtattr *rta;
+
+	if (f == NULL)
+		return skb->len;
+
+	t->tcm_handle = f->handle;
+
+	rta = (struct rtattr *) b;
+	RTA_PUT(skb, TCA_OPTIONS, 0, NULL);
+
+	if (tcf_exts_dump(skb, &f->exts, &basic_ext_map) < 0 ||
+	    tcf_em_tree_dump(skb, &f->ematches, TCA_BASIC_EMATCHES) < 0)
+		goto rtattr_failure;
+
+	rta->rta_len = (skb->tail - b);
+	return skb->len;
+
+rtattr_failure:
+	skb_trim(skb, b - skb->data);
+	return -1;
+}
+
+static struct tcf_proto_ops cls_basic_ops = {
+	.kind		=	"basic",
+	.classify	=	basic_classify,
+	.init		=	basic_init,
+	.destroy	=	basic_destroy,
+	.get		=	basic_get,
+	.put		=	basic_put,
+	.change		=	basic_change,
+	.delete		=	basic_delete,
+	.walk		=	basic_walk,
+	.dump		=	basic_dump,
+	.owner		=	THIS_MODULE,
+};
+
+static int __init init_basic(void)
+{
+	return register_tcf_proto_ops(&cls_basic_ops);
+}
+
+static void __exit exit_basic(void) 
+{
+	unregister_tcf_proto_ops(&cls_basic_ops);
+}
+
+module_init(init_basic)
+module_exit(exit_basic)
+MODULE_LICENSE("GPL");
+