Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 524 insertions, 0 deletions

diff --git a/net/sched/ematch.c b/net/sched/ematch.c
new file mode 100644
index 000000000000..ebfe2e7d21bd
--- /dev/null
+++ b/net/sched/ematch.c
@@ -0,0 +1,524 @@
+/*
+ * 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 <tgraf@suug.ch>
+ *
+ * ==========================================================================
+ *
+ * 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)
+{
+        struct tcf_ematch_ops *e = NULL;
+
+        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;
+                        read_unlock(&ematch_mod_lock);
+                        return e;
+                }
+        }
+        read_unlock(&ematch_mod_lock);
+
+        return NULL;
+}
+
+/**
+ * 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;
+
+        if (ops->match == NULL)
+                return -EINVAL;
+
+        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) {
+                        if (em->ops->destroy)
+                                em->ops->destroy(tp, em);
+                        else if (!tcf_em_is_simple(em) && em->data)
+                                kfree((void *) em->data);
+                        module_put(em->ops->owner);
+                }
+        }
+        
+        tree->hdr.nmatches = 0;
+        kfree(tree->matches);
+}
+
+/**
+ * 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;
+
+rtattr_failure:
+        return -1;
+}
+
+static inline int tcf_em_match(struct sk_buff *skb, struct tcf_ematch *em,
+                               struct tcf_pkt_info *info)
+{
+        int r = em->ops->match(skb, em, info);
+        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);