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 }; 26 27 static int cls_cgroup_classify(struct sk_buff *skb, const struct tcf_proto *tp, 28 struct tcf_result *res) 29 { 30 struct cls_cgroup_head *head = tp->root; 31 u32 classid; 32 33 rcu_read_lock(); 34 classid = task_cls_state(current)->classid; 35 rcu_read_unlock(); 36 37 /* 38 * Due to the nature of the classifier it is required to ignore all 39 * packets originating from softirq context as accessing `current' 40 * would lead to false results. 41 * 42 * This test assumes that all callers of dev_queue_xmit() explicitely 43 * disable bh. Knowing this, it is possible to detect softirq based 44 * calls by looking at the number of nested bh disable calls because 45 * softirqs always disables bh. 46 */ 47 if (in_serving_softirq()) { 48 /* If there is an sk_classid we'll use that. */ 49 if (!skb->sk) 50 return -1; 51 classid = skb->sk->sk_classid; 52 } 53 54 if (!classid) 55 return -1; 56 57 if (!tcf_em_tree_match(skb, &head->ematches, NULL)) 58 return -1; 59 60 res->classid = classid; 61 res->class = 0; 62 return tcf_exts_exec(skb, &head->exts, res); 63 } 64 65 static unsigned long cls_cgroup_get(struct tcf_proto *tp, u32 handle) 66 { 67 return 0UL; 68 } 69 70 static void cls_cgroup_put(struct tcf_proto *tp, unsigned long f) 71 { 72 } 73 74 static int cls_cgroup_init(struct tcf_proto *tp) 75 { 76 return 0; 77 } 78 79 static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = { 80 [TCA_CGROUP_EMATCHES] = { .type = NLA_NESTED }, 81 }; 82 83 static int cls_cgroup_change(struct net *net, struct sk_buff *in_skb, 84 struct tcf_proto *tp, unsigned long base, 85 u32 handle, struct nlattr **tca, 86 unsigned long *arg, bool ovr) 87 { 88 struct nlattr *tb[TCA_CGROUP_MAX + 1]; 89 struct cls_cgroup_head *head = tp->root; 90 struct tcf_ematch_tree t; 91 struct tcf_exts e; 92 int err; 93 94 if (!tca[TCA_OPTIONS]) 95 return -EINVAL; 96 97 if (head == NULL) { 98 if (!handle) 99 return -EINVAL; 100 101 head = kzalloc(sizeof(*head), GFP_KERNEL); 102 if (head == NULL) 103 return -ENOBUFS; 104 105 tcf_exts_init(&head->exts, TCA_CGROUP_ACT, TCA_CGROUP_POLICE); 106 head->handle = handle; 107 108 tcf_tree_lock(tp); 109 tp->root = head; 110 tcf_tree_unlock(tp); 111 } 112 113 if (handle != head->handle) 114 return -ENOENT; 115 116 err = nla_parse_nested(tb, TCA_CGROUP_MAX, tca[TCA_OPTIONS], 117 cgroup_policy); 118 if (err < 0) 119 return err; 120 121 tcf_exts_init(&e, TCA_CGROUP_ACT, TCA_CGROUP_POLICE); 122 err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &e, ovr); 123 if (err < 0) 124 return err; 125 126 err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &t); 127 if (err < 0) 128 return err; 129 130 tcf_exts_change(tp, &head->exts, &e); 131 tcf_em_tree_change(tp, &head->ematches, &t); 132 133 return 0; 134 } 135 136 static void cls_cgroup_destroy(struct tcf_proto *tp) 137 { 138 struct cls_cgroup_head *head = tp->root; 139 140 if (head) { 141 tcf_exts_destroy(tp, &head->exts); 142 tcf_em_tree_destroy(tp, &head->ematches); 143 kfree(head); 144 } 145 } 146 147 static int cls_cgroup_delete(struct tcf_proto *tp, unsigned long arg) 148 { 149 return -EOPNOTSUPP; 150 } 151 152 static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg) 153 { 154 struct cls_cgroup_head *head = tp->root; 155 156 if (arg->count < arg->skip) 157 goto skip; 158 159 if (arg->fn(tp, (unsigned long) head, arg) < 0) { 160 arg->stop = 1; 161 return; 162 } 163 skip: 164 arg->count++; 165 } 166 167 static int cls_cgroup_dump(struct net *net, struct tcf_proto *tp, unsigned long fh, 168 struct sk_buff *skb, struct tcmsg *t) 169 { 170 struct cls_cgroup_head *head = tp->root; 171 unsigned char *b = skb_tail_pointer(skb); 172 struct nlattr *nest; 173 174 t->tcm_handle = head->handle; 175 176 nest = nla_nest_start(skb, TCA_OPTIONS); 177 if (nest == NULL) 178 goto nla_put_failure; 179 180 if (tcf_exts_dump(skb, &head->exts) < 0 || 181 tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0) 182 goto nla_put_failure; 183 184 nla_nest_end(skb, nest); 185 186 if (tcf_exts_dump_stats(skb, &head->exts) < 0) 187 goto nla_put_failure; 188 189 return skb->len; 190 191 nla_put_failure: 192 nlmsg_trim(skb, b); 193 return -1; 194 } 195 196 static struct tcf_proto_ops cls_cgroup_ops __read_mostly = { 197 .kind = "cgroup", 198 .init = cls_cgroup_init, 199 .change = cls_cgroup_change, 200 .classify = cls_cgroup_classify, 201 .destroy = cls_cgroup_destroy, 202 .get = cls_cgroup_get, 203 .put = cls_cgroup_put, 204 .delete = cls_cgroup_delete, 205 .walk = cls_cgroup_walk, 206 .dump = cls_cgroup_dump, 207 .owner = THIS_MODULE, 208 }; 209 210 static int __init init_cgroup_cls(void) 211 { 212 return register_tcf_proto_ops(&cls_cgroup_ops); 213 } 214 215 static void __exit exit_cgroup_cls(void) 216 { 217 unregister_tcf_proto_ops(&cls_cgroup_ops); 218 } 219 220 module_init(init_cgroup_cls); 221 module_exit(exit_cgroup_cls); 222 MODULE_LICENSE("GPL"); 223