Thomas Graf | f400923 | 2008-11-07 22:56:00 -0800 | [diff] [blame] | 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/types.h> |
| 14 | #include <linux/string.h> |
| 15 | #include <linux/errno.h> |
| 16 | #include <linux/skbuff.h> |
| 17 | #include <linux/cgroup.h> |
| 18 | #include <net/rtnetlink.h> |
| 19 | #include <net/pkt_cls.h> |
| 20 | |
| 21 | struct cgroup_cls_state |
| 22 | { |
| 23 | struct cgroup_subsys_state css; |
| 24 | u32 classid; |
| 25 | }; |
| 26 | |
Li Zefan | 8e8ba85 | 2008-12-29 19:39:03 -0800 | [diff] [blame] | 27 | static inline struct cgroup_cls_state *cgrp_cls_state(struct cgroup *cgrp) |
Thomas Graf | f400923 | 2008-11-07 22:56:00 -0800 | [diff] [blame] | 28 | { |
Li Zefan | 8e8ba85 | 2008-12-29 19:39:03 -0800 | [diff] [blame] | 29 | return container_of(cgroup_subsys_state(cgrp, net_cls_subsys_id), |
| 30 | struct cgroup_cls_state, css); |
| 31 | } |
| 32 | |
| 33 | static inline struct cgroup_cls_state *task_cls_state(struct task_struct *p) |
| 34 | { |
| 35 | return container_of(task_subsys_state(p, net_cls_subsys_id), |
| 36 | struct cgroup_cls_state, css); |
Thomas Graf | f400923 | 2008-11-07 22:56:00 -0800 | [diff] [blame] | 37 | } |
| 38 | |
| 39 | static struct cgroup_subsys_state *cgrp_create(struct cgroup_subsys *ss, |
| 40 | struct cgroup *cgrp) |
| 41 | { |
| 42 | struct cgroup_cls_state *cs; |
| 43 | |
| 44 | if (!(cs = kzalloc(sizeof(*cs), GFP_KERNEL))) |
| 45 | return ERR_PTR(-ENOMEM); |
| 46 | |
| 47 | if (cgrp->parent) |
Li Zefan | 8e8ba85 | 2008-12-29 19:39:03 -0800 | [diff] [blame] | 48 | cs->classid = cgrp_cls_state(cgrp->parent)->classid; |
Thomas Graf | f400923 | 2008-11-07 22:56:00 -0800 | [diff] [blame] | 49 | |
| 50 | return &cs->css; |
| 51 | } |
| 52 | |
| 53 | static void cgrp_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp) |
| 54 | { |
Li Zefan | 8e8ba85 | 2008-12-29 19:39:03 -0800 | [diff] [blame] | 55 | kfree(cgrp_cls_state(cgrp)); |
Thomas Graf | f400923 | 2008-11-07 22:56:00 -0800 | [diff] [blame] | 56 | } |
| 57 | |
| 58 | static u64 read_classid(struct cgroup *cgrp, struct cftype *cft) |
| 59 | { |
Li Zefan | 8e8ba85 | 2008-12-29 19:39:03 -0800 | [diff] [blame] | 60 | return cgrp_cls_state(cgrp)->classid; |
Thomas Graf | f400923 | 2008-11-07 22:56:00 -0800 | [diff] [blame] | 61 | } |
| 62 | |
| 63 | static int write_classid(struct cgroup *cgrp, struct cftype *cft, u64 value) |
| 64 | { |
| 65 | if (!cgroup_lock_live_group(cgrp)) |
| 66 | return -ENODEV; |
| 67 | |
Li Zefan | 8e8ba85 | 2008-12-29 19:39:03 -0800 | [diff] [blame] | 68 | cgrp_cls_state(cgrp)->classid = (u32) value; |
Thomas Graf | f400923 | 2008-11-07 22:56:00 -0800 | [diff] [blame] | 69 | |
| 70 | cgroup_unlock(); |
| 71 | |
| 72 | return 0; |
| 73 | } |
| 74 | |
| 75 | static struct cftype ss_files[] = { |
| 76 | { |
| 77 | .name = "classid", |
| 78 | .read_u64 = read_classid, |
| 79 | .write_u64 = write_classid, |
| 80 | }, |
| 81 | }; |
| 82 | |
| 83 | static int cgrp_populate(struct cgroup_subsys *ss, struct cgroup *cgrp) |
| 84 | { |
| 85 | return cgroup_add_files(cgrp, ss, ss_files, ARRAY_SIZE(ss_files)); |
| 86 | } |
| 87 | |
| 88 | struct cgroup_subsys net_cls_subsys = { |
| 89 | .name = "net_cls", |
| 90 | .create = cgrp_create, |
| 91 | .destroy = cgrp_destroy, |
| 92 | .populate = cgrp_populate, |
| 93 | .subsys_id = net_cls_subsys_id, |
| 94 | }; |
| 95 | |
| 96 | struct cls_cgroup_head |
| 97 | { |
| 98 | u32 handle; |
| 99 | struct tcf_exts exts; |
| 100 | struct tcf_ematch_tree ematches; |
| 101 | }; |
| 102 | |
| 103 | static int cls_cgroup_classify(struct sk_buff *skb, struct tcf_proto *tp, |
| 104 | struct tcf_result *res) |
| 105 | { |
| 106 | struct cls_cgroup_head *head = tp->root; |
| 107 | struct cgroup_cls_state *cs; |
| 108 | int ret = 0; |
| 109 | |
| 110 | /* |
| 111 | * Due to the nature of the classifier it is required to ignore all |
| 112 | * packets originating from softirq context as accessing `current' |
| 113 | * would lead to false results. |
| 114 | * |
| 115 | * This test assumes that all callers of dev_queue_xmit() explicitely |
| 116 | * disable bh. Knowing this, it is possible to detect softirq based |
| 117 | * calls by looking at the number of nested bh disable calls because |
| 118 | * softirqs always disables bh. |
| 119 | */ |
| 120 | if (softirq_count() != SOFTIRQ_OFFSET) |
| 121 | return -1; |
| 122 | |
| 123 | rcu_read_lock(); |
Li Zefan | 8e8ba85 | 2008-12-29 19:39:03 -0800 | [diff] [blame] | 124 | cs = task_cls_state(current); |
Thomas Graf | f400923 | 2008-11-07 22:56:00 -0800 | [diff] [blame] | 125 | if (cs->classid && tcf_em_tree_match(skb, &head->ematches, NULL)) { |
| 126 | res->classid = cs->classid; |
| 127 | res->class = 0; |
| 128 | ret = tcf_exts_exec(skb, &head->exts, res); |
| 129 | } else |
| 130 | ret = -1; |
| 131 | |
| 132 | rcu_read_unlock(); |
| 133 | |
| 134 | return ret; |
| 135 | } |
| 136 | |
| 137 | static unsigned long cls_cgroup_get(struct tcf_proto *tp, u32 handle) |
| 138 | { |
| 139 | return 0UL; |
| 140 | } |
| 141 | |
| 142 | static void cls_cgroup_put(struct tcf_proto *tp, unsigned long f) |
| 143 | { |
| 144 | } |
| 145 | |
| 146 | static int cls_cgroup_init(struct tcf_proto *tp) |
| 147 | { |
| 148 | return 0; |
| 149 | } |
| 150 | |
| 151 | static const struct tcf_ext_map cgroup_ext_map = { |
| 152 | .action = TCA_CGROUP_ACT, |
| 153 | .police = TCA_CGROUP_POLICE, |
| 154 | }; |
| 155 | |
| 156 | static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = { |
| 157 | [TCA_CGROUP_EMATCHES] = { .type = NLA_NESTED }, |
| 158 | }; |
| 159 | |
| 160 | static int cls_cgroup_change(struct tcf_proto *tp, unsigned long base, |
| 161 | u32 handle, struct nlattr **tca, |
| 162 | unsigned long *arg) |
| 163 | { |
| 164 | struct nlattr *tb[TCA_CGROUP_MAX+1]; |
| 165 | struct cls_cgroup_head *head = tp->root; |
| 166 | struct tcf_ematch_tree t; |
| 167 | struct tcf_exts e; |
| 168 | int err; |
| 169 | |
| 170 | if (head == NULL) { |
| 171 | if (!handle) |
| 172 | return -EINVAL; |
| 173 | |
| 174 | head = kzalloc(sizeof(*head), GFP_KERNEL); |
| 175 | if (head == NULL) |
| 176 | return -ENOBUFS; |
| 177 | |
| 178 | head->handle = handle; |
| 179 | |
| 180 | tcf_tree_lock(tp); |
| 181 | tp->root = head; |
| 182 | tcf_tree_unlock(tp); |
| 183 | } |
| 184 | |
| 185 | if (handle != head->handle) |
| 186 | return -ENOENT; |
| 187 | |
| 188 | err = nla_parse_nested(tb, TCA_CGROUP_MAX, tca[TCA_OPTIONS], |
| 189 | cgroup_policy); |
| 190 | if (err < 0) |
| 191 | return err; |
| 192 | |
| 193 | err = tcf_exts_validate(tp, tb, tca[TCA_RATE], &e, &cgroup_ext_map); |
| 194 | if (err < 0) |
| 195 | return err; |
| 196 | |
| 197 | err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &t); |
| 198 | if (err < 0) |
| 199 | return err; |
| 200 | |
| 201 | tcf_exts_change(tp, &head->exts, &e); |
| 202 | tcf_em_tree_change(tp, &head->ematches, &t); |
| 203 | |
| 204 | return 0; |
| 205 | } |
| 206 | |
| 207 | static void cls_cgroup_destroy(struct tcf_proto *tp) |
| 208 | { |
Patrick McHardy | 47a1a1d | 2008-11-19 08:03:09 +0000 | [diff] [blame] | 209 | struct cls_cgroup_head *head = tp->root; |
Thomas Graf | f400923 | 2008-11-07 22:56:00 -0800 | [diff] [blame] | 210 | |
| 211 | if (head) { |
| 212 | tcf_exts_destroy(tp, &head->exts); |
| 213 | tcf_em_tree_destroy(tp, &head->ematches); |
| 214 | kfree(head); |
| 215 | } |
| 216 | } |
| 217 | |
| 218 | static int cls_cgroup_delete(struct tcf_proto *tp, unsigned long arg) |
| 219 | { |
| 220 | return -EOPNOTSUPP; |
| 221 | } |
| 222 | |
| 223 | static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg) |
| 224 | { |
| 225 | struct cls_cgroup_head *head = tp->root; |
| 226 | |
| 227 | if (arg->count < arg->skip) |
| 228 | goto skip; |
| 229 | |
| 230 | if (arg->fn(tp, (unsigned long) head, arg) < 0) { |
| 231 | arg->stop = 1; |
| 232 | return; |
| 233 | } |
| 234 | skip: |
| 235 | arg->count++; |
| 236 | } |
| 237 | |
| 238 | static int cls_cgroup_dump(struct tcf_proto *tp, unsigned long fh, |
| 239 | struct sk_buff *skb, struct tcmsg *t) |
| 240 | { |
| 241 | struct cls_cgroup_head *head = tp->root; |
| 242 | unsigned char *b = skb_tail_pointer(skb); |
| 243 | struct nlattr *nest; |
| 244 | |
| 245 | t->tcm_handle = head->handle; |
| 246 | |
| 247 | nest = nla_nest_start(skb, TCA_OPTIONS); |
| 248 | if (nest == NULL) |
| 249 | goto nla_put_failure; |
| 250 | |
| 251 | if (tcf_exts_dump(skb, &head->exts, &cgroup_ext_map) < 0 || |
| 252 | tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0) |
| 253 | goto nla_put_failure; |
| 254 | |
| 255 | nla_nest_end(skb, nest); |
| 256 | |
| 257 | if (tcf_exts_dump_stats(skb, &head->exts, &cgroup_ext_map) < 0) |
| 258 | goto nla_put_failure; |
| 259 | |
| 260 | return skb->len; |
| 261 | |
| 262 | nla_put_failure: |
| 263 | nlmsg_trim(skb, b); |
| 264 | return -1; |
| 265 | } |
| 266 | |
| 267 | static struct tcf_proto_ops cls_cgroup_ops __read_mostly = { |
| 268 | .kind = "cgroup", |
| 269 | .init = cls_cgroup_init, |
| 270 | .change = cls_cgroup_change, |
| 271 | .classify = cls_cgroup_classify, |
| 272 | .destroy = cls_cgroup_destroy, |
| 273 | .get = cls_cgroup_get, |
| 274 | .put = cls_cgroup_put, |
| 275 | .delete = cls_cgroup_delete, |
| 276 | .walk = cls_cgroup_walk, |
| 277 | .dump = cls_cgroup_dump, |
| 278 | .owner = THIS_MODULE, |
| 279 | }; |
| 280 | |
| 281 | static int __init init_cgroup_cls(void) |
| 282 | { |
| 283 | return register_tcf_proto_ops(&cls_cgroup_ops); |
| 284 | } |
| 285 | |
| 286 | static void __exit exit_cgroup_cls(void) |
| 287 | { |
| 288 | unregister_tcf_proto_ops(&cls_cgroup_ops); |
| 289 | } |
| 290 | |
| 291 | module_init(init_cgroup_cls); |
| 292 | module_exit(exit_cgroup_cls); |
| 293 | MODULE_LICENSE("GPL"); |