1 /* 2 * net/sched/cls_cgroup.c Control Group Classifier 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 7 * 2 of the License, or (at your option) any later version. 8 * 9 * Authors: Thomas Graf <tgraf@suug.ch> 10 */ 11 12 #include <linux/module.h> 13 #include <linux/slab.h> 14 #include <linux/skbuff.h> 15 #include <linux/rcupdate.h> 16 #include <net/rtnetlink.h> 17 #include <net/pkt_cls.h> 18 #include <net/sock.h> 19 #include <net/cls_cgroup.h> 20 21 struct cls_cgroup_head { 22 u32 handle; 23 struct tcf_exts exts; 24 struct tcf_ematch_tree ematches; 25 struct tcf_proto *tp; 26 struct rcu_head rcu; 27 }; 28 29 static int cls_cgroup_classify(struct sk_buff *skb, const struct tcf_proto *tp, 30 struct tcf_result *res) 31 { 32 struct cls_cgroup_head *head = rcu_dereference_bh(tp->root); 33 u32 classid = task_get_classid(skb); 34 35 if (!classid) 36 return -1; 37 if (!tcf_em_tree_match(skb, &head->ematches, NULL)) 38 return -1; 39 40 res->classid = classid; 41 res->class = 0; 42 43 return tcf_exts_exec(skb, &head->exts, res); 44 } 45 46 static unsigned long cls_cgroup_get(struct tcf_proto *tp, u32 handle) 47 { 48 return 0UL; 49 } 50 51 static int cls_cgroup_init(struct tcf_proto *tp) 52 { 53 return 0; 54 } 55 56 static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = { 57 [TCA_CGROUP_EMATCHES] = { .type = NLA_NESTED }, 58 }; 59 60 static void cls_cgroup_destroy_rcu(struct rcu_head *root) 61 { 62 struct cls_cgroup_head *head = container_of(root, 63 struct cls_cgroup_head, 64 rcu); 65 66 tcf_exts_destroy(&head->exts); 67 tcf_em_tree_destroy(&head->ematches); 68 kfree(head); 69 } 70 71 static int cls_cgroup_change(struct net *net, struct sk_buff *in_skb, 72 struct tcf_proto *tp, unsigned long base, 73 u32 handle, struct nlattr **tca, 74 unsigned long *arg, bool ovr) 75 { 76 struct nlattr *tb[TCA_CGROUP_MAX + 1]; 77 struct cls_cgroup_head *head = rtnl_dereference(tp->root); 78 struct cls_cgroup_head *new; 79 struct tcf_ematch_tree t; 80 struct tcf_exts e; 81 int err; 82 83 if (!tca[TCA_OPTIONS]) 84 return -EINVAL; 85 86 if (!head && !handle) 87 return -EINVAL; 88 89 if (head && handle != head->handle) 90 return -ENOENT; 91 92 new = kzalloc(sizeof(*head), GFP_KERNEL); 93 if (!new) 94 return -ENOBUFS; 95 96 err = tcf_exts_init(&new->exts, TCA_CGROUP_ACT, TCA_CGROUP_POLICE); 97 if (err < 0) 98 goto errout; 99 new->handle = handle; 100 new->tp = tp; 101 err = nla_parse_nested(tb, TCA_CGROUP_MAX, tca[TCA_OPTIONS], 102 cgroup_policy); 103 if (err < 0) 104 goto errout; 105 106 err = tcf_exts_init(&e, TCA_CGROUP_ACT, TCA_CGROUP_POLICE); 107 if (err < 0) 108 goto errout; 109 err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &e, ovr); 110 if (err < 0) { 111 tcf_exts_destroy(&e); 112 goto errout; 113 } 114 115 err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &t); 116 if (err < 0) { 117 tcf_exts_destroy(&e); 118 goto errout; 119 } 120 121 tcf_exts_change(tp, &new->exts, &e); 122 tcf_em_tree_change(tp, &new->ematches, &t); 123 124 rcu_assign_pointer(tp->root, new); 125 if (head) 126 call_rcu(&head->rcu, cls_cgroup_destroy_rcu); 127 return 0; 128 errout: 129 tcf_exts_destroy(&new->exts); 130 kfree(new); 131 return err; 132 } 133 134 static bool cls_cgroup_destroy(struct tcf_proto *tp, bool force) 135 { 136 struct cls_cgroup_head *head = rtnl_dereference(tp->root); 137 138 if (!force) 139 return false; 140 /* Head can still be NULL due to cls_cgroup_init(). */ 141 if (head) 142 call_rcu(&head->rcu, cls_cgroup_destroy_rcu); 143 144 return true; 145 } 146 147 static int cls_cgroup_delete(struct tcf_proto *tp, unsigned long arg) 148 { 149 return -EOPNOTSUPP; 150 } 151 152 static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg) 153 { 154 struct cls_cgroup_head *head = rtnl_dereference(tp->root); 155 156 if (arg->count < arg->skip) 157 goto skip; 158 159 if (arg->fn(tp, (unsigned long) head, arg) < 0) { 160 arg->stop = 1; 161 return; 162 } 163 skip: 164 arg->count++; 165 } 166 167 static int cls_cgroup_dump(struct net *net, struct tcf_proto *tp, unsigned long fh, 168 struct sk_buff *skb, struct tcmsg *t) 169 { 170 struct cls_cgroup_head *head = rtnl_dereference(tp->root); 171 struct nlattr *nest; 172 173 t->tcm_handle = head->handle; 174 175 nest = nla_nest_start(skb, TCA_OPTIONS); 176 if (nest == NULL) 177 goto nla_put_failure; 178 179 if (tcf_exts_dump(skb, &head->exts) < 0 || 180 tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0) 181 goto nla_put_failure; 182 183 nla_nest_end(skb, nest); 184 185 if (tcf_exts_dump_stats(skb, &head->exts) < 0) 186 goto nla_put_failure; 187 188 return skb->len; 189 190 nla_put_failure: 191 nla_nest_cancel(skb, nest); 192 return -1; 193 } 194 195 static struct tcf_proto_ops cls_cgroup_ops __read_mostly = { 196 .kind = "cgroup", 197 .init = cls_cgroup_init, 198 .change = cls_cgroup_change, 199 .classify = cls_cgroup_classify, 200 .destroy = cls_cgroup_destroy, 201 .get = cls_cgroup_get, 202 .delete = cls_cgroup_delete, 203 .walk = cls_cgroup_walk, 204 .dump = cls_cgroup_dump, 205 .owner = THIS_MODULE, 206 }; 207 208 static int __init init_cgroup_cls(void) 209 { 210 return register_tcf_proto_ops(&cls_cgroup_ops); 211 } 212 213 static void __exit exit_cgroup_cls(void) 214 { 215 unregister_tcf_proto_ops(&cls_cgroup_ops); 216 } 217 218 module_init(init_cgroup_cls); 219 module_exit(exit_cgroup_cls); 220 MODULE_LICENSE("GPL"); 221