3 files changed, 302 insertions, 0 deletions

diff --git a/net/sched/Kconfig b/net/sched/Kconfig
index 6767e54155db..36543b6fcef3 100644
--- a/net/sched/Kconfig
+++ b/net/sched/Kconfig
@@ -316,6 +316,17 @@ config NET_CLS_FLOW
           To compile this code as a module, choose M here: the
           module will be called cls_flow.
 
+config NET_CLS_CGROUP
+        bool "Control Group Classifier"
+        select NET_CLS
+        depends on CGROUPS
+        ---help---
+          Say Y here if you want to classify packets based on the control
+          cgroup of their process.
+
+          To compile this code as a module, choose M here: the
+          module will be called cls_cgroup.
+
 config NET_EMATCH
         bool "Extended Matches"
         select NET_CLS
diff --git a/net/sched/Makefile b/net/sched/Makefile
index e60c9925b269..70b35f8708c3 100644
--- a/net/sched/Makefile
+++ b/net/sched/Makefile
@@ -38,6 +38,7 @@ 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_CLS_FLOW)      += cls_flow.o
+obj-$(CONFIG_NET_CLS_CGROUP)    += cls_cgroup.o
 obj-$(CONFIG_NET_EMATCH)        += ematch.o
 obj-$(CONFIG_NET_EMATCH_CMP)    += em_cmp.o
 obj-$(CONFIG_NET_EMATCH_NBYTE)  += em_nbyte.o
diff --git a/net/sched/cls_cgroup.c b/net/sched/cls_cgroup.c
new file mode 100644
index 000000000000..53ada2c0e41c
--- /dev/null
+++ b/net/sched/cls_cgroup.c
@@ -0,0 +1,290 @@
+/*
+ * 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/types.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/skbuff.h>
+#include <linux/cgroup.h>
+#include <net/rtnetlink.h>
+#include <net/pkt_cls.h>
+
+struct cgroup_cls_state
+{
+        struct cgroup_subsys_state css;
+        u32 classid;
+};
+
+static inline struct cgroup_cls_state *net_cls_state(struct cgroup *cgrp)
+{
+        return (struct cgroup_cls_state *)
+                cgroup_subsys_state(cgrp, net_cls_subsys_id);
+}
+
+static struct cgroup_subsys_state *cgrp_create(struct cgroup_subsys *ss,
+                                                 struct cgroup *cgrp)
+{
+        struct cgroup_cls_state *cs;
+
+        if (!(cs = kzalloc(sizeof(*cs), GFP_KERNEL)))
+                return ERR_PTR(-ENOMEM);
+
+        if (cgrp->parent)
+                cs->classid = net_cls_state(cgrp->parent)->classid;
+
+        return &cs->css;
+}
+
+static void cgrp_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
+{
+        kfree(ss);
+}
+
+static u64 read_classid(struct cgroup *cgrp, struct cftype *cft)
+{
+        return net_cls_state(cgrp)->classid;
+}
+
+static int write_classid(struct cgroup *cgrp, struct cftype *cft, u64 value)
+{
+        if (!cgroup_lock_live_group(cgrp))
+                return -ENODEV;
+
+        net_cls_state(cgrp)->classid = (u32) value;
+
+        cgroup_unlock();
+
+        return 0;
+}
+
+static struct cftype ss_files[] = {
+        {
+                .name = "classid",
+                .read_u64 = read_classid,
+                .write_u64 = write_classid,
+        },
+};
+
+static int cgrp_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
+{
+        return cgroup_add_files(cgrp, ss, ss_files, ARRAY_SIZE(ss_files));
+}
+
+struct cgroup_subsys net_cls_subsys = {
+        .name           = "net_cls",
+        .create         = cgrp_create,
+        .destroy        = cgrp_destroy,
+        .populate       = cgrp_populate,
+        .subsys_id      = net_cls_subsys_id,
+};
+
+struct cls_cgroup_head
+{
+        u32                     handle;
+        struct tcf_exts         exts;
+        struct tcf_ematch_tree  ematches;
+};
+
+static int cls_cgroup_classify(struct sk_buff *skb, struct tcf_proto *tp,
+                               struct tcf_result *res)
+{
+        struct cls_cgroup_head *head = tp->root;
+        struct cgroup_cls_state *cs;
+        int ret = 0;
+
+        /*
+         * 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 (softirq_count() != SOFTIRQ_OFFSET)
+                return -1;
+
+        rcu_read_lock();
+        cs = (struct cgroup_cls_state *) task_subsys_state(current,
+                                                           net_cls_subsys_id);
+        if (cs->classid && tcf_em_tree_match(skb, &head->ematches, NULL)) {
+                res->classid = cs->classid;
+                res->class = 0;
+                ret = tcf_exts_exec(skb, &head->exts, res);
+        } else
+                ret = -1;
+
+        rcu_read_unlock();
+
+        return ret;
+}
+
+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 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 (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(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;
+
+        head = (struct cls_cgroup_head *)xchg(&tp->root, NULL);
+
+        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)
+{
+        return register_tcf_proto_ops(&cls_cgroup_ops);
+}
+
+static void __exit exit_cgroup_cls(void)
+{
+        unregister_tcf_proto_ops(&cls_cgroup_ops);
+}
+
+module_init(init_cgroup_cls);
+module_exit(exit_cgroup_cls);
+MODULE_LICENSE("GPL");