| 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_LICENSE("GPL"); |