Extended matches and basic classifier

diff -Nru linux-2.6.11-rc2-bk1.orig/include/net/pkt_cls.h linux-2.6.11-rc2-bk1/include/net/pkt_cls.h

include/net/pkt_cls.h +19 -0

@@ -148,6 +148,176 @@
 extern int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts,
 	                       struct tcf_ext_map *map);
 
+/**
+ * struct tcf_pkt_info - packet information
+ */
+struct tcf_pkt_info
+{
+};
+
+#ifdef CONFIG_NET_EMATCH
+
+struct tcf_ematch_ops;
+
+/**
+ * struct tcf_ematch - extended match (ematch)
+ * 
+ * @matchid: identifier to allow userspace to reidentify a match
+ * @flags: flags specifying attributes and the relation to other matches
+ * @ops: the operations lookup table of the corresponding ematch module
+ * @datalen: length of the ematch specific configuration data
+ * @data: ematch specific data

diff -Nru linux-2.6.11-rc2-bk1.orig/net/sched/ematch.c linux-2.6.11-rc2-bk1/net/sched/ematch.c

net/sched/ematch.c +101 -0

@@ -0,0 +1,526 @@
+/*
+ * net/sched/ematch.c		Extended Match API
+ *
+ *		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 <[email protected]>
+ *
+ * ==========================================================================
+ *
+ * An extended match (ematch) is a small classification tool not worth
+ * writing a full classifier for. Ematches can be interconnected to form
+ * a logic expression and get attached to classifiers to extend their
+ * functionatlity.
+ *
+ * The userspace part transforms the logic expressions into an array
+ * consisting of multiple sequences of interconnected ematches separated
+ * by markers. Precedence is implemented by a special ematch kind
+ * referencing a sequence beyond the marker of the current sequence
+ * causing the current position in the sequence to be pushed onto a stack
+ * to allow the current position to be overwritten by the position referenced
+ * in the special ematch. Matching continues in the new sequence until a
+ * marker is reached causing the position to be restored from the stack.
+ *
+ * Example:
+ *          A AND (B1 OR B2) AND C AND D
+ *
+ *              ------->-PUSH-------
+ *    -->--    /         -->--      \   -->--
+ *   /     \  /         /     \      \ /     \
+ * +-------+-------+-------+-------+-------+--------+
+ * | A AND | B AND | C AND | D END | B1 OR | B2 END |
+ * +-------+-------+-------+-------+-------+--------+
+ *                    \                      /
+ *                     --------<-POP---------
+ *
+ * where B is a virtual ematch referencing to sequence starting with B1.
+ * 
+ * ==========================================================================
+ *
+ * How to write an ematch in 60 seconds
+ * ------------------------------------
+ * 
+ *   1) Provide a matcher function:
+ *      static int my_match(struct sk_buff *skb, struct tcf_ematch *m,
+ *                          struct tcf_pkt_info *info)
+ *      {
+ *      	struct mydata *d = (struct mydata *) m->data;
+ *
+ *      	if (...matching goes here...)
+ *      		return 1;
+ *      	else
+ *      		return 0;
+ *      }
+ *
+ *   2) Fill out a struct tcf_ematch_ops:
+ *      static struct tcf_ematch_ops my_ops = {
+ *      	.kind = unique id,
+ *      	.datalen = sizeof(struct mydata),
+ *      	.match = my_match,
+ *      	.owner = THIS_MODULE,
+ *      };
+ *
+ *   3) Register/Unregister your ematch:
+ *      static int __init init_my_ematch(void)
+ *      {
+ *      	return tcf_em_register(&my_ops);
+ *      }
+ *
+ *      static void __exit exit_my_ematch(void)
+ *      {
+ *      	return tcf_em_unregister(&my_ops);
+ *      }
+ *
+ *      module_init(init_my_ematch);
+ *      module_exit(exit_my_ematch);
+ *
+ *   4) By now you should have two more seconds left, barely enough to
+ *      open up a beer to watch the compilation going.
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/rtnetlink.h>
+#include <linux/skbuff.h>
+#include <net/pkt_cls.h>
+#include <config/net/ematch/stack.h>
+
+static LIST_HEAD(ematch_ops);
+static DEFINE_RWLOCK(ematch_mod_lock);
+
+static inline struct tcf_ematch_ops * tcf_em_lookup(u16 kind)
 
+{

net/sched/ematch.c +278 -0

+	read_unlock(&ematch_mod_lock);
+
+	return e;
+}
+
+/**
+ * tcf_em_register - register an extended match
+ * 
+ * @ops: ematch operations lookup table
+ *
+ * This function must be called by ematches to announce their presence.
+ * The given @ops must have kind set to a unique identifier and the
+ * callback match() must be implemented. All other callbacks are optional
+ * and a fallback implementation is used instead.
+ *
+ * Returns -EEXISTS if an ematch of the same kind has already registered.
+ */
+int tcf_em_register(struct tcf_ematch_ops *ops)
+{
+	int err = -EEXIST;
+	struct tcf_ematch_ops *e;
+
+	write_lock(&ematch_mod_lock);
+	list_for_each_entry(e, &ematch_ops, link)
+		if (ops->kind == e->kind)
+			goto errout;
+
+	list_add_tail(&ops->link, &ematch_ops);
+	err = 0;
+errout:
+	write_unlock(&ematch_mod_lock);
+	return err;
+}
+
+/**
+ * tcf_em_unregister - unregster and extended match
+ *
+ * @ops: ematch operations lookup table
+ *
+ * This function must be called by ematches to announce their disappearance
+ * for examples when the module gets unloaded. The @ops parameter must be
+ * the same as the one used for registration.
+ *
+ * Returns -ENOENT if no matching ematch was found.
+ */
+int tcf_em_unregister(struct tcf_ematch_ops *ops)
+{
+	int err = 0;
+	struct tcf_ematch_ops *e;
+
+	write_lock(&ematch_mod_lock);
+	list_for_each_entry(e, &ematch_ops, link) {
+		if (e == ops) {
+			list_del(&e->link);
+			goto out;
+		}
+	}
+
+	err = -ENOENT;
+out:
+	write_unlock(&ematch_mod_lock);
+	return err;
+}
+
+static inline struct tcf_ematch * tcf_em_get_match(struct tcf_ematch_tree *tree,
+						   int index)
+{
+	return &tree->matches[index];
+}
+
+
+static int tcf_em_validate(struct tcf_proto *tp,
+			   struct tcf_ematch_tree_hdr *tree_hdr,
+			   struct tcf_ematch *em, struct rtattr *rta, int idx)
+{
+	int err = -EINVAL;
+	struct tcf_ematch_hdr *em_hdr = RTA_DATA(rta);
+	int data_len = RTA_PAYLOAD(rta) - sizeof(*em_hdr);
+	void *data = (void *) em_hdr + sizeof(*em_hdr);
+
+	if (!TCF_EM_REL_VALID(em_hdr->flags))
+		goto errout;
+
+	if (em_hdr->kind == TCF_EM_CONTAINER) {
+		/* Special ematch called "container", carries an index
+		 * referencing an external ematch sequence. */
+		u32 ref;
+
+		if (data_len < sizeof(ref))
+			goto errout;
+		ref = *(u32 *) data;
+
+		if (ref >= tree_hdr->nmatches)
+			goto errout;
+
+		/* We do not allow backward jumps to avoid loops and jumps
+		 * to our own position are of course illegal. */
+		if (ref <= idx)
+			goto errout;
+
+		
+		em->data = ref;
+	} else {
+		/* Note: This lookup will increase the module refcnt
+		 * of the ematch module referenced. In case of a failure,
+		 * a destroy function is called by the underlying layer
+		 * which automatically releases the reference again, therefore
+		 * the module MUST not be given back under any circumstances
+		 * here. Be aware, the destroy function assumes that the
+		 * module is held if the ops field is non zero. */
+		em->ops = tcf_em_lookup(em_hdr->kind);
+
+		if (em->ops == NULL) {
+			err = -ENOENT;
+			goto errout;
+		}
+
+		/* ematch module provides expected length of data, so we
+		 * can do a basic sanity check. */
+		if (em->ops->datalen && data_len < em->ops->datalen)
+			goto errout;
+
+		if (em->ops->change) {
+			err = em->ops->change(tp, data, data_len, em);
+			if (err < 0)
+				goto errout;
+		} else if (data_len > 0) {
+			/* ematch module doesn't provide an own change
+			 * procedure and expects us to allocate and copy
+			 * the ematch data.
+			 *
+			 * TCF_EM_SIMPLE may be specified stating that the
+			 * data only consists of a u32 integer and the module
+			 * does not expected a memory reference but rather
+			 * the value carried. */
+			if (em_hdr->flags & TCF_EM_SIMPLE) {
+				if (data_len < sizeof(u32))
+					goto errout;
+				em->data = *(u32 *) data;
+			} else {
+				void *v = kmalloc(data_len, GFP_KERNEL);
+				if (v == NULL) {
+					err = -ENOBUFS;
+					goto errout;
+				}
+				memcpy(v, data, data_len);
+				em->data = (unsigned long) v;
+			}
+		}
+	}
+
+	em->matchid = em_hdr->matchid;
+	em->flags = em_hdr->flags;
+	em->datalen = data_len;
+
+	err = 0;
+errout:
+	return err;
+}
+
+/**
+ * tcf_em_tree_validate - validate ematch config TLV and build ematch tree
+ *
+ * @tp: classifier kind handle
+ * @rta: ematch tree configuration TLV
+ * @tree: destination ematch tree variable to store the resulting
+ *        ematch tree.
+ *
+ * This function validates the given configuration TLV @rta and builds an
+ * ematch tree in @tree. The resulting tree must later be copied into
+ * the private classifier data using tcf_em_tree_change(). You MUST NOT
+ * provide the ematch tree variable of the private classifier data directly,
+ * the changes would not be locked properly.
+ *
+ * Returns a negative error code if the configuration TLV contains errors.
+ */
+int tcf_em_tree_validate(struct tcf_proto *tp, struct rtattr *rta,
+			 struct tcf_ematch_tree *tree)
+{
+	int idx, list_len, matches_len, err = -EINVAL;
+	struct rtattr *tb[TCA_EMATCH_TREE_MAX];
+	struct rtattr *rt_match, *rt_hdr, *rt_list;
+	struct tcf_ematch_tree_hdr *tree_hdr;
+	struct tcf_ematch *em;
+
+	if (rtattr_parse_nested(tb, TCA_EMATCH_TREE_MAX, rta) < 0)
+		goto errout;
+
+	rt_hdr = tb[TCA_EMATCH_TREE_HDR-1];
+	rt_list = tb[TCA_EMATCH_TREE_LIST-1];
+
+	if (rt_hdr == NULL || rt_list == NULL)
+		goto errout;
+
+	if (RTA_PAYLOAD(rt_hdr) < sizeof(*tree_hdr) ||
+	    RTA_PAYLOAD(rt_list) < sizeof(*rt_match))
+		goto errout;
+
+	tree_hdr = RTA_DATA(rt_hdr);
+	memcpy(&tree->hdr, tree_hdr, sizeof(*tree_hdr));
+
+	rt_match = RTA_DATA(rt_list);
+	list_len = RTA_PAYLOAD(rt_list);
+	matches_len = tree_hdr->nmatches * sizeof(*em);
+
+	tree->matches = kmalloc(matches_len, GFP_KERNEL);
+	if (tree->matches == NULL)
+		goto errout;
+	memset(tree->matches, 0, matches_len);
+
+	/* We do not use rtattr_parse_nested here because the maximum
+	 * number of attributes is unknown. This saves us the allocation
+	 * for a tb buffer which would serve no purpose at all.
+	 * 
+	 * The array of rt attributes is parsed in the order as they are
+	 * provided, their type must be incremental from 1 to n. Even
+	 * if it does not serve any real purpose, a failure of sticking
+	 * to this policy will result in parsing failure. */
+	for (idx = 0; RTA_OK(rt_match, list_len); idx++) {
+		err = -EINVAL;
+
+		if (rt_match->rta_type != (idx + 1))
+			goto errout_abort;
+
+		if (idx >= tree_hdr->nmatches)
+			goto errout_abort;
+
+		if (RTA_PAYLOAD(rt_match) < sizeof(struct tcf_ematch_hdr))
+			goto errout_abort;
+
+		em = tcf_em_get_match(tree, idx);
+
+		err = tcf_em_validate(tp, tree_hdr, em, rt_match, idx);
+		if (err < 0)
+			goto errout_abort;
+
+		rt_match = RTA_NEXT(rt_match, list_len);
+	}
+
+	/* Check if the number of matches provided by userspace actually
+	 * complies with the array of matches. The number was used for
+	 * the validation of references and a mismatch could lead to
+	 * undefined references during the matching process. */
+	if (idx != tree_hdr->nmatches) {
+		err = -EINVAL;
+		goto errout_abort;
+	}
+
+	err = 0;
+errout:
+	return err;
+
+errout_abort:
+	tcf_em_tree_destroy(tp, tree);
+	return err;
+}
+
+/**
+ * tcf_em_tree_destroy - destroy an ematch tree
+ *
+ * @tp: classifier kind handle
+ * @tree: ematch tree to be deleted
+ *
+ * This functions destroys an ematch tree previously created by
+ * tcf_em_tree_validate()/tcf_em_tree_change(). You must ensure that
+ * the ematch tree is not in use before calling this function.
+ */
+void tcf_em_tree_destroy(struct tcf_proto *tp, struct tcf_ematch_tree *tree)
+{
+	int i;
+
+	if (tree->matches == NULL)
+		return;
+
+	for (i = 0; i < tree->hdr.nmatches; i++) {
+		struct tcf_ematch *em = tcf_em_get_match(tree, i);
+
+		if (em->ops) {

net/sched/ematch.c +54 -0

+}
+
+/**
+ * tcf_em_tree_dump - dump ematch tree into a rtnl message
+ *
+ * @skb: skb holding the rtnl message
+ * @t: ematch tree to be dumped
+ * @tlv: TLV type to be used to encapsulate the tree
+ *
+ * This function dumps a ematch tree into a rtnl message. It is valid to
+ * call this function while the ematch tree is in use.
+ *
+ * Returns -1 if the skb tailroom is insufficient.
+ */
+int tcf_em_tree_dump(struct sk_buff *skb, struct tcf_ematch_tree *tree, int tlv)
+{
+	int i;
+	struct rtattr * top_start = (struct rtattr*) skb->tail;
+	struct rtattr * list_start;
+
+	RTA_PUT(skb, tlv, 0, NULL);
+	RTA_PUT(skb, TCA_EMATCH_TREE_HDR, sizeof(tree->hdr), &tree->hdr);
+
+	list_start = (struct rtattr *) skb->tail;
+	RTA_PUT(skb, TCA_EMATCH_TREE_LIST, 0, NULL);
+
+	for (i = 0; i < tree->hdr.nmatches; i++) {
+		struct rtattr *match_start = (struct rtattr*) skb->tail;
+		struct tcf_ematch *em = tcf_em_get_match(tree, i);
+		struct tcf_ematch_hdr em_hdr = {
+			.kind = em->ops ? em->ops->kind : TCF_EM_CONTAINER,
+			.matchid = em->matchid,
+			.flags = em->flags
+		};
+
+		RTA_PUT(skb, i+1, sizeof(em_hdr), &em_hdr);
+
+		if (em->ops && em->ops->dump) {
+			if (em->ops->dump(skb, em) < 0)
+				goto rtattr_failure;
+		} else if (tcf_em_is_container(em) || tcf_em_is_simple(em)) {
+			u32 u = em->data;
+			RTA_PUT_NOHDR(skb, sizeof(u), &u);
+		} else if (em->datalen > 0)
+			RTA_PUT_NOHDR(skb, em->datalen, (void *) em->data);
+
+		match_start->rta_len = skb->tail - (u8*) match_start;
+	}
+
+	list_start->rta_len = skb->tail - (u8 *) list_start;
+	top_start->rta_len = skb->tail - (u8 *) top_start;
+
+	return 0;
+

net/sched/ematch.c +63 -0

+		r = em->ops->match(skb, em, info);
+	else
+		r = 0;
+
+	return tcf_em_is_inverted(em) ? !r : r;
+}
+
+/* Do not use this function directly, use tcf_em_tree_match instead */
+int __tcf_em_tree_match(struct sk_buff *skb, struct tcf_ematch_tree *tree,
+			struct tcf_pkt_info *info)
+{
+	int stackp = 0, match_idx = 0, res = 0;
+	struct tcf_ematch *cur_match;
+	int stack[CONFIG_NET_EMATCH_STACK];
 
 
+
+proceed:
+	while (match_idx < tree->hdr.nmatches) {
+		cur_match = tcf_em_get_match(tree, match_idx);
+
+		if (tcf_em_is_container(cur_match)) {
+			if (unlikely(stackp >= CONFIG_NET_EMATCH_STACK))
+				goto stack_overflow;
+
+			stack[stackp++] = match_idx;
+			match_idx = cur_match->data;
+			goto proceed;
+		}
+
+		res = tcf_em_match(skb, cur_match, info);
+
+		if (tcf_em_early_end(cur_match, res))
+			break;
+
+		match_idx++;
+	}
+
+pop_stack:
+	if (stackp > 0) {
+		match_idx = stack[--stackp];
+		cur_match = tcf_em_get_match(tree, match_idx);
+
+		if (tcf_em_early_end(cur_match, res))
+			goto pop_stack;
+		else {
+			match_idx++;
+			goto proceed;
+		}
+	}
+
+	return res;
+
+stack_overflow:
+	if (net_ratelimit())
+		printk("Local stack overflow, increase NET_EMATCH_STACK\n");
+	return -1;
+}
+
+EXPORT_SYMBOL(tcf_em_register);
+EXPORT_SYMBOL(tcf_em_unregister);
+EXPORT_SYMBOL(tcf_em_tree_validate);
+EXPORT_SYMBOL(tcf_em_tree_destroy);
+EXPORT_SYMBOL(tcf_em_tree_dump);
+EXPORT_SYMBOL(__tcf_em_tree_match);

include/net/pkt_cls.h line 178

Quoted 9 lines · Thomas Graf

include/net/pkt_cls.h +8 -0

+struct tcf_ematch
+{
+	u16			matchid;
+	u16			flags;
+	struct tcf_ematch_ops * ops;
+	unsigned int		datalen;
+	unsigned long		data;
+};

This layout leaves two holes on 64 bit, how about:

{
   struct tcf_ematch_ops *ops;
   unsigned long data;
   unsigned int datalen;
   u16 matchid;
   u16 flags;
};

net/sched/ematch.c line 111

Quoted 9 lines

net/sched/ematch.c +8 -0

+	read_lock(&ematch_mod_lock);
+	list_for_each_entry(e, &ematch_ops, link) {
+		if (kind == e->kind) {
+			if (!try_module_get(e->owner))
+				e = NULL;
+			break;
+		}
+	}

e is the iterator, if nothing matched it will contain the last element now

net/sched/ematch.c line 399

Quoted 4 lines

net/sched/ematch.c +2 -0

+	tree->hdr.nmatches = 0;
+	kfree(xchg(&tree->matches, NULL));

xchg is not necessary here. Setting tree->matches to NULL also doesn't look necessary. As the comment above indicates, the caller needs to ensure the tree is unsused, so it should be easy for him to ensure he won't destroy the same tree twice.

net/sched/ematch.c line 463

Quoted 8 lines

net/sched/ematch.c +6 -0

+static inline int tcf_em_match(struct sk_buff *skb, struct tcf_ematch *em,
+			       struct tcf_pkt_info *info)
+{
+	int r;
+
+	if (likely(em->ops->match))

gcc assumes likely for ptr != NULL by default. Is there a reason why a match wouldn't have a match function ?

* Patrick McHardy <[email protected]> 2005-01-24 01:12

Quoted 3 lines

gcc assumes likely for ptr != NULL by default. Is there a reason why a match wouldn't have a match function ?

There is no reason but ematches might get written by unexperienced people forgeting to register it. I know, the if partly hides the failure, it's one of theses case where I have the same arguments for both ways.

Quoted 8 lines · Thomas Graf

* Patrick McHardy <[email protected]> 2005-01-24 01:12

Quoted 4 lines

gcc assumes likely for ptr != NULL by default. Is there a reason why a match
wouldn't have a match function ?

Quoted 4 lines

There is no reason but ematches might get written by unexperienced people forgeting to register it. I know, the if partly hides the failure, it's one of theses case where I have the same arguments for both ways.

I don't care much, but I guess people forgetting to add a match function to an ematch will find other ways to do stupid things :) How about catching it in tcf_em_register ?

diff -Nru linux-2.6.11-rc2-bk1.orig/net/sched/em_cmp.c linux-2.6.11-rc2-bk1/net/sched/em_cmp.c

net/sched/em_cmp.c +35 -0

@@ -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 <[email protected]>
+ */
+
+#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) {

net/sched/em_cmp.c +56 -0

+			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);
+

Quoted 16 lines · Thomas Graf

net/sched/em_cmp.c +16 -0

+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:

net/sched/em_cmp.c line 45

Quoted 7 lines

net/sched/em_cmp.c +5 -0

+			val = *ptr << 8;
+			val |= *(ptr+1);
+
+			if (cmp_needs_transformation(cmp))
+				val = be16_to_cpu(val);

Why not simply convert cmp->val in userspace ?

diff -Nru linux-2.6.11-rc1-bk9.orig/net/sched/em_u32.c linux-2.6.11-rc1-bk9/net/sched/em_u32.c

net/sched/em_u32.c +24 -0

@@ -0,0 +1,58 @@
+/*
+ * net/sched/em_u32.c	U32 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 <[email protected]>
+ *		Alexey Kuznetsov, <[email protected]>
+ *
+ * Based on net/sched/cls_u32.c
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <net/pkt_cls.h>
+
+static int em_u32_match(struct sk_buff *skb, struct tcf_ematch *em,
+			struct tcf_pkt_info *info)
+{

net/sched/em_u32.c +24 -0

+}
+
+static struct tcf_ematch_ops em_u32_ops = {
+	.kind	  = TCF_EM_U32,
+	.datalen  = sizeof(struct tc_u32_key),
+	.match	  = em_u32_match,
+	.owner	  = THIS_MODULE,
+	.link	  = LIST_HEAD_INIT(em_u32_ops.link)
+};
+
+static int __init init_em_u32(void)
+{
+	return tcf_em_register(&em_u32_ops);
+}
+
+static void __exit exit_em_u32(void) 
+{
+	tcf_em_unregister(&em_u32_ops);
+}
+
+MODULE_LICENSE("GPL");
+
+module_init(init_em_u32);
+module_exit(exit_em_u32);

Quoted 9 lines · Thomas Graf

net/sched/em_u32.c +9 -0

+static int em_u32_match(struct sk_buff *skb, struct tcf_ematch *em,
+			struct tcf_pkt_info *info)
+{
+	struct tc_u32_key *key = (struct tc_u32_key *) em->data;
+	unsigned char *ptr = skb->nh.raw;
+	
+	if (info) {
+		if (info->ptr)
+			ptr = info->ptr;

net/sched/em_u32.c line 34

Quoted 6 lines

net/sched/em_u32.c +4 -0

+		ptr += (info->nexthdr & key->offmask);
+	}
+	
+	return !((*(u32*) (ptr + key->off) ^ key->val) & key->mask);

This needs to make sure it stays inside the skb. I know cls_u32's checks are pretty weak, but having nothing doesn't seem right.

This patchset adds the ematch API, the ematches cmp, nbyte, u32, meta, and the basic classifier. It doesn't touch any existing code.

This patchset adds the ematch API, the ematches cmp, nbyte, u32, meta, and the basic classifier. It doesn't touch any existing code.

This patchset adds the ematch API, the ematches cmp, nbyte, u32, meta, and the basic classifier. It doesn't touch any existing code.