1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * net/sched/cls_cgroup.c Control Group Classifier 4 * 5 * Authors: Thomas Graf <tgraf@suug.ch> 6 */ 7 8 #include <linux/module.h> 9 #include <linux/slab.h> 10 #include <linux/skbuff.h> 11 #include <linux/rcupdate.h> 12 #include <net/rtnetlink.h> 13 #include <net/pkt_cls.h> 14 #include <net/sock.h> 15 #include <net/cls_cgroup.h> 16 17 struct cls_cgroup_head { 18 u32 handle; 19 struct tcf_exts exts; 20 struct tcf_ematch_tree ematches; 21 struct tcf_proto *tp; 22 struct rcu_work rwork; 23 }; 24 25 static int cls_cgroup_classify(struct sk_buff *skb, const struct tcf_proto *tp, 26 struct tcf_result *res) 27 { 28 struct cls_cgroup_head *head = rcu_dereference_bh(tp->root); 29 u32 classid = task_get_classid(skb); 30 31 if (unlikely(!head)) 32 return -1; 33 if (!classid) 34 return -1; 35 if (!tcf_em_tree_match(skb, &head->ematches, NULL)) 36 return -1; 37 38 res->classid = classid; 39 res->class = 0; 40 41 return tcf_exts_exec(skb, &head->exts, res); 42 } 43 44 static void *cls_cgroup_get(struct tcf_proto *tp, u32 handle) 45 { 46 return NULL; 47 } 48 49 static int cls_cgroup_init(struct tcf_proto *tp) 50 { 51 return 0; 52 } 53 54 static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = { 55 [TCA_CGROUP_EMATCHES] = { .type = NLA_NESTED }, 56 }; 57 58 static void __cls_cgroup_destroy(struct cls_cgroup_head *head) 59 { 60 tcf_exts_destroy(&head->exts); 61 tcf_em_tree_destroy(&head->ematches); 62 tcf_exts_put_net(&head->exts); 63 kfree(head); 64 } 65 66 static void cls_cgroup_destroy_work(struct work_struct *work) 67 { 68 struct cls_cgroup_head *head = container_of(to_rcu_work(work), 69 struct cls_cgroup_head, 70 rwork); 71 rtnl_lock(); 72 __cls_cgroup_destroy(head); 73 rtnl_unlock(); 74 } 75 76 static int cls_cgroup_change(struct net *net, struct sk_buff *in_skb, 77 struct tcf_proto *tp, unsigned long base, 78 u32 handle, struct nlattr **tca, 79 void **arg, u32 flags, 80 struct netlink_ext_ack *extack) 81 { 82 struct nlattr *tb[TCA_CGROUP_MAX + 1]; 83 struct cls_cgroup_head *head = rtnl_dereference(tp->root); 84 struct cls_cgroup_head *new; 85 int err; 86 87 if (!tca[TCA_OPTIONS]) 88 return -EINVAL; 89 90 if (!head && !handle) 91 return -EINVAL; 92 93 if (head && handle != head->handle) 94 return -ENOENT; 95 96 new = kzalloc(sizeof(*head), GFP_KERNEL); 97 if (!new) 98 return -ENOBUFS; 99 100 err = tcf_exts_init(&new->exts, net, TCA_CGROUP_ACT, TCA_CGROUP_POLICE); 101 if (err < 0) 102 goto errout; 103 new->handle = handle; 104 new->tp = tp; 105 err = nla_parse_nested_deprecated(tb, TCA_CGROUP_MAX, 106 tca[TCA_OPTIONS], cgroup_policy, 107 NULL); 108 if (err < 0) 109 goto errout; 110 111 err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &new->exts, flags, 112 extack); 113 if (err < 0) 114 goto errout; 115 116 err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &new->ematches); 117 if (err < 0) 118 goto errout; 119 120 rcu_assign_pointer(tp->root, new); 121 if (head) { 122 tcf_exts_get_net(&head->exts); 123 tcf_queue_work(&head->rwork, cls_cgroup_destroy_work); 124 } 125 return 0; 126 errout: 127 tcf_exts_destroy(&new->exts); 128 kfree(new); 129 return err; 130 } 131 132 static void cls_cgroup_destroy(struct tcf_proto *tp, bool rtnl_held, 133 struct netlink_ext_ack *extack) 134 { 135 struct cls_cgroup_head *head = rtnl_dereference(tp->root); 136 137 /* Head can still be NULL due to cls_cgroup_init(). */ 138 if (head) { 139 if (tcf_exts_get_net(&head->exts)) 140 tcf_queue_work(&head->rwork, cls_cgroup_destroy_work); 141 else 142 __cls_cgroup_destroy(head); 143 } 144 } 145 146 static int cls_cgroup_delete(struct tcf_proto *tp, void *arg, bool *last, 147 bool rtnl_held, struct netlink_ext_ack *extack) 148 { 149 return -EOPNOTSUPP; 150 } 151 152 static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg, 153 bool rtnl_held) 154 { 155 struct cls_cgroup_head *head = rtnl_dereference(tp->root); 156 157 if (arg->count < arg->skip) 158 goto skip; 159 160 if (!head) 161 return; 162 if (arg->fn(tp, head, arg) < 0) { 163 arg->stop = 1; 164 return; 165 } 166 skip: 167 arg->count++; 168 } 169 170 static int cls_cgroup_dump(struct net *net, struct tcf_proto *tp, void *fh, 171 struct sk_buff *skb, struct tcmsg *t, bool rtnl_held) 172 { 173 struct cls_cgroup_head *head = rtnl_dereference(tp->root); 174 struct nlattr *nest; 175 176 t->tcm_handle = head->handle; 177 178 nest = nla_nest_start_noflag(skb, TCA_OPTIONS); 179 if (nest == NULL) 180 goto nla_put_failure; 181 182 if (tcf_exts_dump(skb, &head->exts) < 0 || 183 tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0) 184 goto nla_put_failure; 185 186 nla_nest_end(skb, nest); 187 188 if (tcf_exts_dump_stats(skb, &head->exts) < 0) 189 goto nla_put_failure; 190 191 return skb->len; 192 193 nla_put_failure: 194 nla_nest_cancel(skb, nest); 195 return -1; 196 } 197 198 static struct tcf_proto_ops cls_cgroup_ops __read_mostly = { 199 .kind = "cgroup", 200 .init = cls_cgroup_init, 201 .change = cls_cgroup_change, 202 .classify = cls_cgroup_classify, 203 .destroy = cls_cgroup_destroy, 204 .get = cls_cgroup_get, 205 .delete = cls_cgroup_delete, 206 .walk = cls_cgroup_walk, 207 .dump = cls_cgroup_dump, 208 .owner = THIS_MODULE, 209 }; 210 211 static int __init init_cgroup_cls(void) 212 { 213 return register_tcf_proto_ops(&cls_cgroup_ops); 214 } 215 216 static void __exit exit_cgroup_cls(void) 217 { 218 unregister_tcf_proto_ops(&cls_cgroup_ops); 219 } 220 221 module_init(init_cgroup_cls); 222 module_exit(exit_cgroup_cls); 223 MODULE_LICENSE("GPL"); 224