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_work rwork; 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(struct cls_cgroup_head *head) 61 { 62 tcf_exts_destroy(&head->exts); 63 tcf_em_tree_destroy(&head->ematches); 64 tcf_exts_put_net(&head->exts); 65 kfree(head); 66 } 67 68 static void cls_cgroup_destroy_work(struct work_struct *work) 69 { 70 struct cls_cgroup_head *head = container_of(to_rcu_work(work), 71 struct cls_cgroup_head, 72 rwork); 73 rtnl_lock(); 74 __cls_cgroup_destroy(head); 75 rtnl_unlock(); 76 } 77 78 static int cls_cgroup_change(struct net *net, struct sk_buff *in_skb, 79 struct tcf_proto *tp, unsigned long base, 80 u32 handle, struct nlattr **tca, 81 void **arg, bool ovr, bool rtnl_held, 82 struct netlink_ext_ack *extack) 83 { 84 struct nlattr *tb[TCA_CGROUP_MAX + 1]; 85 struct cls_cgroup_head *head = rtnl_dereference(tp->root); 86 struct cls_cgroup_head *new; 87 int err; 88 89 if (!tca[TCA_OPTIONS]) 90 return -EINVAL; 91 92 if (!head && !handle) 93 return -EINVAL; 94 95 if (head && handle != head->handle) 96 return -ENOENT; 97 98 new = kzalloc(sizeof(*head), GFP_KERNEL); 99 if (!new) 100 return -ENOBUFS; 101 102 err = tcf_exts_init(&new->exts, net, TCA_CGROUP_ACT, TCA_CGROUP_POLICE); 103 if (err < 0) 104 goto errout; 105 new->handle = handle; 106 new->tp = tp; 107 err = nla_parse_nested(tb, TCA_CGROUP_MAX, tca[TCA_OPTIONS], 108 cgroup_policy, NULL); 109 if (err < 0) 110 goto errout; 111 112 err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &new->exts, ovr, 113 true, extack); 114 if (err < 0) 115 goto errout; 116 117 err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &new->ematches); 118 if (err < 0) 119 goto errout; 120 121 rcu_assign_pointer(tp->root, new); 122 if (head) { 123 tcf_exts_get_net(&head->exts); 124 tcf_queue_work(&head->rwork, cls_cgroup_destroy_work); 125 } 126 return 0; 127 errout: 128 tcf_exts_destroy(&new->exts); 129 kfree(new); 130 return err; 131 } 132 133 static void cls_cgroup_destroy(struct tcf_proto *tp, bool rtnl_held, 134 struct netlink_ext_ack *extack) 135 { 136 struct cls_cgroup_head *head = rtnl_dereference(tp->root); 137 138 /* Head can still be NULL due to cls_cgroup_init(). */ 139 if (head) { 140 if (tcf_exts_get_net(&head->exts)) 141 tcf_queue_work(&head->rwork, cls_cgroup_destroy_work); 142 else 143 __cls_cgroup_destroy(head); 144 } 145 } 146 147 static int cls_cgroup_delete(struct tcf_proto *tp, void *arg, bool *last, 148 bool rtnl_held, struct netlink_ext_ack *extack) 149 { 150 return -EOPNOTSUPP; 151 } 152 153 static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg, 154 bool rtnl_held) 155 { 156 struct cls_cgroup_head *head = rtnl_dereference(tp->root); 157 158 if (arg->count < arg->skip) 159 goto skip; 160 161 if (!head) 162 return; 163 if (arg->fn(tp, head, arg) < 0) { 164 arg->stop = 1; 165 return; 166 } 167 skip: 168 arg->count++; 169 } 170 171 static int cls_cgroup_dump(struct net *net, struct tcf_proto *tp, void *fh, 172 struct sk_buff *skb, struct tcmsg *t, bool rtnl_held) 173 { 174 struct cls_cgroup_head *head = rtnl_dereference(tp->root); 175 struct nlattr *nest; 176 177 t->tcm_handle = head->handle; 178 179 nest = nla_nest_start(skb, TCA_OPTIONS); 180 if (nest == NULL) 181 goto nla_put_failure; 182 183 if (tcf_exts_dump(skb, &head->exts) < 0 || 184 tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0) 185 goto nla_put_failure; 186 187 nla_nest_end(skb, nest); 188 189 if (tcf_exts_dump_stats(skb, &head->exts) < 0) 190 goto nla_put_failure; 191 192 return skb->len; 193 194 nla_put_failure: 195 nla_nest_cancel(skb, nest); 196 return -1; 197 } 198 199 static struct tcf_proto_ops cls_cgroup_ops __read_mostly = { 200 .kind = "cgroup", 201 .init = cls_cgroup_init, 202 .change = cls_cgroup_change, 203 .classify = cls_cgroup_classify, 204 .destroy = cls_cgroup_destroy, 205 .get = cls_cgroup_get, 206 .delete = cls_cgroup_delete, 207 .walk = cls_cgroup_walk, 208 .dump = cls_cgroup_dump, 209 .owner = THIS_MODULE, 210 }; 211 212 static int __init init_cgroup_cls(void) 213 { 214 return register_tcf_proto_ops(&cls_cgroup_ops); 215 } 216 217 static void __exit exit_cgroup_cls(void) 218 { 219 unregister_tcf_proto_ops(&cls_cgroup_ops); 220 } 221 222 module_init(init_cgroup_cls); 223 module_exit(exit_cgroup_cls); 224 MODULE_LICENSE("GPL"); 225