/* * 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 *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_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 = cgrp_cls_state(cgrp->parent)->classid; return &cs->css; } static void cgrp_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp) { kfree(cgrp_cls_state(cgrp)); } 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) { if (!cgroup_lock_live_group(cgrp)) return -ENODEV; cgrp_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 = task_cls_state(current); 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 = 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) { 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");