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 void *cls_cgroup_get(struct tcf_proto *tp, u32 handle) 47 { 48 return NULL; 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 void **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 int err; 80 81 if (!tca[TCA_OPTIONS]) 82 return -EINVAL; 83 84 if (!head && !handle) 85 return -EINVAL; 86 87 if (head && handle != head->handle) 88 return -ENOENT; 89 90 new = kzalloc(sizeof(*head), GFP_KERNEL); 91 if (!new) 92 return -ENOBUFS; 93 94 err = tcf_exts_init(&new->exts, TCA_CGROUP_ACT, TCA_CGROUP_POLICE); 95 if (err < 0) 96 goto errout; 97 new->handle = handle; 98 new->tp = tp; 99 err = nla_parse_nested(tb, TCA_CGROUP_MAX, tca[TCA_OPTIONS], 100 cgroup_policy, NULL); 101 if (err < 0) 102 goto errout; 103 104 err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &new->exts, ovr); 105 if (err < 0) 106 goto errout; 107 108 err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &new->ematches); 109 if (err < 0) 110 goto errout; 111 112 rcu_assign_pointer(tp->root, new); 113 if (head) 114 call_rcu(&head->rcu, cls_cgroup_destroy_rcu); 115 return 0; 116 errout: 117 tcf_exts_destroy(&new->exts); 118 kfree(new); 119 return err; 120 } 121 122 static void cls_cgroup_destroy(struct tcf_proto *tp) 123 { 124 struct cls_cgroup_head *head = rtnl_dereference(tp->root); 125 126 /* Head can still be NULL due to cls_cgroup_init(). */ 127 if (head) 128 call_rcu(&head->rcu, cls_cgroup_destroy_rcu); 129 } 130 131 static int cls_cgroup_delete(struct tcf_proto *tp, void *arg, bool *last) 132 { 133 return -EOPNOTSUPP; 134 } 135 136 static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg) 137 { 138 struct cls_cgroup_head *head = rtnl_dereference(tp->root); 139 140 if (arg->count < arg->skip) 141 goto skip; 142 143 if (arg->fn(tp, head, arg) < 0) { 144 arg->stop = 1; 145 return; 146 } 147 skip: 148 arg->count++; 149 } 150 151 static int cls_cgroup_dump(struct net *net, struct tcf_proto *tp, void *fh, 152 struct sk_buff *skb, struct tcmsg *t) 153 { 154 struct cls_cgroup_head *head = rtnl_dereference(tp->root); 155 struct nlattr *nest; 156 157 t->tcm_handle = head->handle; 158 159 nest = nla_nest_start(skb, TCA_OPTIONS); 160 if (nest == NULL) 161 goto nla_put_failure; 162 163 if (tcf_exts_dump(skb, &head->exts) < 0 || 164 tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0) 165 goto nla_put_failure; 166 167 nla_nest_end(skb, nest); 168 169 if (tcf_exts_dump_stats(skb, &head->exts) < 0) 170 goto nla_put_failure; 171 172 return skb->len; 173 174 nla_put_failure: 175 nla_nest_cancel(skb, nest); 176 return -1; 177 } 178 179 static struct tcf_proto_ops cls_cgroup_ops __read_mostly = { 180 .kind = "cgroup", 181 .init = cls_cgroup_init, 182 .change = cls_cgroup_change, 183 .classify = cls_cgroup_classify, 184 .destroy = cls_cgroup_destroy, 185 .get = cls_cgroup_get, 186 .delete = cls_cgroup_delete, 187 .walk = cls_cgroup_walk, 188 .dump = cls_cgroup_dump, 189 .owner = THIS_MODULE, 190 }; 191 192 static int __init init_cgroup_cls(void) 193 { 194 return register_tcf_proto_ops(&cls_cgroup_ops); 195 } 196 197 static void __exit exit_cgroup_cls(void) 198 { 199 unregister_tcf_proto_ops(&cls_cgroup_ops); 200 } 201 202 module_init(init_cgroup_cls); 203 module_exit(exit_cgroup_cls); 204 MODULE_LICENSE("GPL"); 205