1 files changed, 332 insertions, 0 deletions
diff --git a/net/sched/cls_cgroup.c b/net/sched/cls_cgroup.c
new file mode 100644
index 00000000..3a294eb9
--- /dev/null
+++ b/net/sched/cls_cgroup.c
@@ -0,0 +1,332 @@
+/*
+ * net/sched/cls_cgroup.c	Control Group 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/module.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/skbuff.h>
+#include <linux/cgroup.h>
+#include <linux/rcupdate.h>
+#include <linux/fdtable.h>
+#include <net/rtnetlink.h>
+#include <net/pkt_cls.h>
+#include <net/sock.h>
+#include <net/cls_cgroup.h>
+
+static inline struct cgroup_cls_state *cgrp_cls_state(struct cgroup *cgrp)
+{
+	return container_of(cgroup_subsys_state(cgrp, net_cls_subsys_id),
+			    struct cgroup_cls_state, css);
+}
+
+static inline struct cgroup_cls_state *task_cls_state(struct task_struct *p)
+{
+	return container_of(task_subsys_state(p, net_cls_subsys_id),
+			    struct cgroup_cls_state, css);
+}
+
+static struct cgroup_subsys_state *cgrp_css_alloc(struct cgroup *cgrp)
+{
+	struct cgroup_cls_state *cs;
+
+	cs = kzalloc(sizeof(*cs), GFP_KERNEL);
+	if (!cs)
+		return ERR_PTR(-ENOMEM);
+	return &cs->css;
+}
+
+static int cgrp_css_online(struct cgroup *cgrp)
+{
+	if (cgrp->parent)
+		cgrp_cls_state(cgrp)->classid =
+			cgrp_cls_state(cgrp->parent)->classid;
+	return 0;
+}
+
+static void cgrp_css_free(struct cgroup *cgrp)
+{
+	kfree(cgrp_cls_state(cgrp));
+}
+
+static int update_classid(const void *v, struct file *file, unsigned n)
+{
+	int err;
+	struct socket *sock = sock_from_file(file, &err);
+	if (sock)
+		sock->sk->sk_classid = (u32)(unsigned long)v;
+	return 0;
+}
+
+static void cgrp_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
+{
+	struct task_struct *p;
+	void *v;
+
+	cgroup_taskset_for_each(p, cgrp, tset) {
+		task_lock(p);
+		v = (void *)(unsigned long)task_cls_classid(p);
+		iterate_fd(p->files, 0, update_classid, v);
+		task_unlock(p);
+	}
+}
+
+static u64 read_classid(struct cgroup *cgrp, struct cftype *cft)
+{
+	return cgrp_cls_state(cgrp)->classid;
+}
+
+static int write_classid(struct cgroup *cgrp, struct cftype *cft, u64 value)
+{
+	cgrp_cls_state(cgrp)->classid = (u32) value;
+	return 0;
+}
+
+static struct cftype ss_files[] = {
+	{
+		.name = "classid",
+		.read_u64 = read_classid,
+		.write_u64 = write_classid,
+	},
+	{ }	/* terminate */
+};
+
+struct cgroup_subsys net_cls_subsys = {
+	.name		= "net_cls",
+	.css_alloc	= cgrp_css_alloc,
+	.css_online	= cgrp_css_online,
+	.css_free	= cgrp_css_free,
+	.attach		= cgrp_attach,
+	.subsys_id	= net_cls_subsys_id,
+	.base_cftypes	= ss_files,
+	.module		= THIS_MODULE,
+};
+
+struct cls_cgroup_head {
+	u32			handle;
+	struct tcf_exts		exts;
+	struct tcf_ematch_tree	ematches;
+};
+
+static int cls_cgroup_classify(struct sk_buff *skb, const struct tcf_proto *tp,
+			       struct tcf_result *res)
+{
+	struct cls_cgroup_head *head = tp->root;
+	u32 classid;
+
+	rcu_read_lock();
+	classid = task_cls_state(current)->classid;
+	rcu_read_unlock();
+
+	/*
+	 * Due to the nature of the classifier it is required to ignore all
+	 * packets originating from softirq context as accessing `current'
+	 * would lead to false results.
+	 *
+	 * This test assumes that all callers of dev_queue_xmit() explicitely
+	 * disable bh. Knowing this, it is possible to detect softirq based
+	 * calls by looking at the number of nested bh disable calls because
+	 * softirqs always disables bh.
+	 */
+	if (in_serving_softirq()) {
+		/* If there is an sk_classid we'll use that. */
+		if (!skb->sk)
+			return -1;
+		classid = skb->sk->sk_classid;
+	}
+
+	if (!classid)
+		return -1;
+
+	if (!tcf_em_tree_match(skb, &head->ematches, NULL))
+		return -1;
+
+	res->classid = classid;
+	res->class = 0;
+	return tcf_exts_exec(skb, &head->exts, res);
+}
+
+static unsigned long cls_cgroup_get(struct tcf_proto *tp, u32 handle)
+{
+	return 0UL;
+}
+
+static void cls_cgroup_put(struct tcf_proto *tp, unsigned long f)
+{
+}
+
+static int cls_cgroup_init(struct tcf_proto *tp)
+{
+	return 0;
+}
+
+static const struct tcf_ext_map cgroup_ext_map = {
+	.action = TCA_CGROUP_ACT,
+	.police = TCA_CGROUP_POLICE,
+};
+
+static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = {
+	[TCA_CGROUP_EMATCHES]	= { .type = NLA_NESTED },
+};
+
+static int cls_cgroup_change(struct net *net, struct sk_buff *in_skb,
+			     struct tcf_proto *tp, unsigned long base,
+			     u32 handle, struct nlattr **tca,
+			     unsigned long *arg)
+{
+	struct nlattr *tb[TCA_CGROUP_MAX + 1];
+	struct cls_cgroup_head *head = tp->root;
+	struct tcf_ematch_tree t;
+	struct tcf_exts e;
+	int err;
+
+	if (!tca[TCA_OPTIONS])
+		return -EINVAL;
+
+	if (head == NULL) {
+		if (!handle)
+			return -EINVAL;
+
+		head = kzalloc(sizeof(*head), GFP_KERNEL);
+		if (head == NULL)
+			return -ENOBUFS;
+
+		head->handle = handle;
+
+		tcf_tree_lock(tp);
+		tp->root = head;
+		tcf_tree_unlock(tp);
+	}
+
+	if (handle != head->handle)
+		return -ENOENT;
+
+	err = nla_parse_nested(tb, TCA_CGROUP_MAX, tca[TCA_OPTIONS],
+			       cgroup_policy);
+	if (err < 0)
+		return err;
+
+	err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &e,
+				&cgroup_ext_map);
+	if (err < 0)
+		return err;
+
+	err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &t);
+	if (err < 0)
+		return err;
+
+	tcf_exts_change(tp, &head->exts, &e);
+	tcf_em_tree_change(tp, &head->ematches, &t);
+
+	return 0;
+}
+
+static void cls_cgroup_destroy(struct tcf_proto *tp)
+{
+	struct cls_cgroup_head *head = tp->root;
+
+	if (head) {
+		tcf_exts_destroy(tp, &head->exts);
+		tcf_em_tree_destroy(tp, &head->ematches);
+		kfree(head);
+	}
+}
+
+static int cls_cgroup_delete(struct tcf_proto *tp, unsigned long arg)
+{
+	return -EOPNOTSUPP;
+}
+
+static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg)
+{
+	struct cls_cgroup_head *head = tp->root;
+
+	if (arg->count < arg->skip)
+		goto skip;
+
+	if (arg->fn(tp, (unsigned long) head, arg) < 0) {
+		arg->stop = 1;
+		return;
+	}
+skip:
+	arg->count++;
+}
+
+static int cls_cgroup_dump(struct tcf_proto *tp, unsigned long fh,
+			   struct sk_buff *skb, struct tcmsg *t)
+{
+	struct cls_cgroup_head *head = tp->root;
+	unsigned char *b = skb_tail_pointer(skb);
+	struct nlattr *nest;
+
+	t->tcm_handle = head->handle;
+
+	nest = nla_nest_start(skb, TCA_OPTIONS);
+	if (nest == NULL)
+		goto nla_put_failure;
+
+	if (tcf_exts_dump(skb, &head->exts, &cgroup_ext_map) < 0 ||
+	    tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0)
+		goto nla_put_failure;
+
+	nla_nest_end(skb, nest);
+
+	if (tcf_exts_dump_stats(skb, &head->exts, &cgroup_ext_map) < 0)
+		goto nla_put_failure;
+
+	return skb->len;
+
+nla_put_failure:
+	nlmsg_trim(skb, b);
+	return -1;
+}
+
+static struct tcf_proto_ops cls_cgroup_ops __read_mostly = {
+	.kind		=	"cgroup",
+	.init		=	cls_cgroup_init,
+	.change		=	cls_cgroup_change,
+	.classify	=	cls_cgroup_classify,
+	.destroy	=	cls_cgroup_destroy,
+	.get		=	cls_cgroup_get,
+	.put		=	cls_cgroup_put,
+	.delete		=	cls_cgroup_delete,
+	.walk		=	cls_cgroup_walk,
+	.dump		=	cls_cgroup_dump,
+	.owner		=	THIS_MODULE,
+};
+
+static int __init init_cgroup_cls(void)
+{
+	int ret;
+
+	ret = cgroup_load_subsys(&net_cls_subsys);
+	if (ret)
+		goto out;
+
+	ret = register_tcf_proto_ops(&cls_cgroup_ops);
+	if (ret)
+		cgroup_unload_subsys(&net_cls_subsys);
+
+out:
+	return ret;
+}
+
+static void __exit exit_cgroup_cls(void)
+{
+	unregister_tcf_proto_ops(&cls_cgroup_ops);
+
+	cgroup_unload_subsys(&net_cls_subsys);
+}
+
+module_init(init_cgroup_cls);
+module_exit(exit_cgroup_cls);
+MODULE_LICENSE("GPL");