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 #include <net/tc_wrapper.h> 17 18 struct cls_cgroup_head { 19 u32 handle; 20 struct tcf_exts exts; 21 struct tcf_ematch_tree ematches; 22 struct tcf_proto *tp; 23 struct rcu_work rwork; 24 }; 25 26 TC_INDIRECT_SCOPE int cls_cgroup_classify(struct sk_buff *skb, 27 const struct tcf_proto *tp, 28 struct tcf_result *res) 29 { 30 struct cls_cgroup_head *head = rcu_dereference_bh(tp->root); 31 u32 classid = task_get_classid(skb); 32 33 if (unlikely(!head)) 34 return -1; 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, u32 flags, 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_deprecated(tb, TCA_CGROUP_MAX, 108 tca[TCA_OPTIONS], cgroup_policy, 109 NULL); 110 if (err < 0) 111 goto errout; 112 113 err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &new->exts, flags, 114 extack); 115 if (err < 0) 116 goto errout; 117 118 err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &new->ematches); 119 if (err < 0) 120 goto errout; 121 122 rcu_assign_pointer(tp->root, new); 123 if (head) { 124 tcf_exts_get_net(&head->exts); 125 tcf_queue_work(&head->rwork, cls_cgroup_destroy_work); 126 } 127 return 0; 128 errout: 129 tcf_exts_destroy(&new->exts); 130 kfree(new); 131 return err; 132 } 133 134 static void cls_cgroup_destroy(struct tcf_proto *tp, bool rtnl_held, 135 struct netlink_ext_ack *extack) 136 { 137 struct cls_cgroup_head *head = rtnl_dereference(tp->root); 138 139 /* Head can still be NULL due to cls_cgroup_init(). */ 140 if (head) { 141 if (tcf_exts_get_net(&head->exts)) 142 tcf_queue_work(&head->rwork, cls_cgroup_destroy_work); 143 else 144 __cls_cgroup_destroy(head); 145 } 146 } 147 148 static int cls_cgroup_delete(struct tcf_proto *tp, void *arg, bool *last, 149 bool rtnl_held, struct netlink_ext_ack *extack) 150 { 151 return -EOPNOTSUPP; 152 } 153 154 static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg, 155 bool rtnl_held) 156 { 157 struct cls_cgroup_head *head = rtnl_dereference(tp->root); 158 159 if (arg->count < arg->skip) 160 goto skip; 161 162 if (!head) 163 return; 164 if (arg->fn(tp, head, arg) < 0) { 165 arg->stop = 1; 166 return; 167 } 168 skip: 169 arg->count++; 170 } 171 172 static int cls_cgroup_dump(struct net *net, struct tcf_proto *tp, void *fh, 173 struct sk_buff *skb, struct tcmsg *t, bool rtnl_held) 174 { 175 struct cls_cgroup_head *head = rtnl_dereference(tp->root); 176 struct nlattr *nest; 177 178 t->tcm_handle = head->handle; 179 180 nest = nla_nest_start_noflag(skb, TCA_OPTIONS); 181 if (nest == NULL) 182 goto nla_put_failure; 183 184 if (tcf_exts_dump(skb, &head->exts) < 0 || 185 tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0) 186 goto nla_put_failure; 187 188 nla_nest_end(skb, nest); 189 190 if (tcf_exts_dump_stats(skb, &head->exts) < 0) 191 goto nla_put_failure; 192 193 return skb->len; 194 195 nla_put_failure: 196 nla_nest_cancel(skb, nest); 197 return -1; 198 } 199 200 static struct tcf_proto_ops cls_cgroup_ops __read_mostly = { 201 .kind = "cgroup", 202 .init = cls_cgroup_init, 203 .change = cls_cgroup_change, 204 .classify = cls_cgroup_classify, 205 .destroy = cls_cgroup_destroy, 206 .get = cls_cgroup_get, 207 .delete = cls_cgroup_delete, 208 .walk = cls_cgroup_walk, 209 .dump = cls_cgroup_dump, 210 .owner = THIS_MODULE, 211 }; 212 213 static int __init init_cgroup_cls(void) 214 { 215 return register_tcf_proto_ops(&cls_cgroup_ops); 216 } 217 218 static void __exit exit_cgroup_cls(void) 219 { 220 unregister_tcf_proto_ops(&cls_cgroup_ops); 221 } 222 223 module_init(init_cgroup_cls); 224 module_exit(exit_cgroup_cls); 225 MODULE_DESCRIPTION("TC cgroup classifier"); 226 MODULE_LICENSE("GPL"); 227