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11
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14#include <linux/module.h>
15#include <linux/slab.h>
16#include <linux/types.h>
17#include <linux/string.h>
18#include <linux/errno.h>
19#include <linux/skbuff.h>
20#include <linux/cgroup.h>
21#include <linux/rcupdate.h>
22#include <linux/atomic.h>
23#include <net/rtnetlink.h>
24#include <net/pkt_cls.h>
25#include <net/sock.h>
26#include <net/netprio_cgroup.h>
27
28#include <linux/fdtable.h>
29
30#define PRIOMAP_MIN_SZ 128
31
32static inline struct cgroup_netprio_state *cgrp_netprio_state(struct cgroup *cgrp)
33{
34 return container_of(cgroup_subsys_state(cgrp, net_prio_subsys_id),
35 struct cgroup_netprio_state, css);
36}
37
38
39
40
41
42
43static int extend_netdev_table(struct net_device *dev, u32 target_idx)
44{
45 struct netprio_map *old, *new;
46 size_t new_sz, new_len;
47
48
49 old = rtnl_dereference(dev->priomap);
50 if (old && old->priomap_len > target_idx)
51 return 0;
52
53
54
55
56
57
58 new_sz = PRIOMAP_MIN_SZ;
59 while (true) {
60 new_len = (new_sz - offsetof(struct netprio_map, priomap)) /
61 sizeof(new->priomap[0]);
62 if (new_len > target_idx)
63 break;
64 new_sz *= 2;
65
66 if (WARN_ON(new_sz < PRIOMAP_MIN_SZ))
67 return -ENOSPC;
68 }
69
70
71 new = kzalloc(new_sz, GFP_KERNEL);
72 if (!new)
73 return -ENOMEM;
74
75 if (old)
76 memcpy(new->priomap, old->priomap,
77 old->priomap_len * sizeof(old->priomap[0]));
78
79 new->priomap_len = new_len;
80
81
82 rcu_assign_pointer(dev->priomap, new);
83 if (old)
84 kfree_rcu(old, rcu);
85 return 0;
86}
87
88
89
90
91
92
93
94
95static u32 netprio_prio(struct cgroup *cgrp, struct net_device *dev)
96{
97 struct netprio_map *map = rcu_dereference_rtnl(dev->priomap);
98
99 if (map && cgrp->id < map->priomap_len)
100 return map->priomap[cgrp->id];
101 return 0;
102}
103
104
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110
111
112
113static int netprio_set_prio(struct cgroup *cgrp, struct net_device *dev,
114 u32 prio)
115{
116 struct netprio_map *map;
117 int ret;
118
119
120 map = rtnl_dereference(dev->priomap);
121 if (!prio && (!map || map->priomap_len <= cgrp->id))
122 return 0;
123
124 ret = extend_netdev_table(dev, cgrp->id);
125 if (ret)
126 return ret;
127
128 map = rtnl_dereference(dev->priomap);
129 map->priomap[cgrp->id] = prio;
130 return 0;
131}
132
133static struct cgroup_subsys_state *cgrp_css_alloc(struct cgroup *cgrp)
134{
135 struct cgroup_netprio_state *cs;
136
137 cs = kzalloc(sizeof(*cs), GFP_KERNEL);
138 if (!cs)
139 return ERR_PTR(-ENOMEM);
140
141 return &cs->css;
142}
143
144static int cgrp_css_online(struct cgroup *cgrp)
145{
146 struct cgroup *parent = cgrp->parent;
147 struct net_device *dev;
148 int ret = 0;
149
150 if (!parent)
151 return 0;
152
153 rtnl_lock();
154
155
156
157
158 for_each_netdev(&init_net, dev) {
159 u32 prio = netprio_prio(parent, dev);
160
161 ret = netprio_set_prio(cgrp, dev, prio);
162 if (ret)
163 break;
164 }
165 rtnl_unlock();
166 return ret;
167}
168
169static void cgrp_css_free(struct cgroup *cgrp)
170{
171 kfree(cgrp_netprio_state(cgrp));
172}
173
174static u64 read_prioidx(struct cgroup *cgrp, struct cftype *cft)
175{
176 return cgrp->id;
177}
178
179static int read_priomap(struct cgroup *cont, struct cftype *cft,
180 struct cgroup_map_cb *cb)
181{
182 struct net_device *dev;
183
184 rcu_read_lock();
185 for_each_netdev_rcu(&init_net, dev)
186 cb->fill(cb, dev->name, netprio_prio(cont, dev));
187 rcu_read_unlock();
188 return 0;
189}
190
191static int write_priomap(struct cgroup *cgrp, struct cftype *cft,
192 const char *buffer)
193{
194 char devname[IFNAMSIZ + 1];
195 struct net_device *dev;
196 u32 prio;
197 int ret;
198
199 if (sscanf(buffer, "%"__stringify(IFNAMSIZ)"s %u", devname, &prio) != 2)
200 return -EINVAL;
201
202 dev = dev_get_by_name(&init_net, devname);
203 if (!dev)
204 return -ENODEV;
205
206 rtnl_lock();
207
208 ret = netprio_set_prio(cgrp, dev, prio);
209
210 rtnl_unlock();
211 dev_put(dev);
212 return ret;
213}
214
215static int update_netprio(const void *v, struct file *file, unsigned n)
216{
217 int err;
218 struct socket *sock = sock_from_file(file, &err);
219 if (sock)
220 sock->sk->sk_cgrp_prioidx = (u32)(unsigned long)v;
221 return 0;
222}
223
224static void net_prio_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
225{
226 struct task_struct *p;
227 void *v;
228
229 cgroup_taskset_for_each(p, cgrp, tset) {
230 task_lock(p);
231 v = (void *)(unsigned long)task_netprioidx(p);
232 iterate_fd(p->files, 0, update_netprio, v);
233 task_unlock(p);
234 }
235}
236
237static struct cftype ss_files[] = {
238 {
239 .name = "prioidx",
240 .read_u64 = read_prioidx,
241 },
242 {
243 .name = "ifpriomap",
244 .read_map = read_priomap,
245 .write_string = write_priomap,
246 },
247 { }
248};
249
250struct cgroup_subsys net_prio_subsys = {
251 .name = "net_prio",
252 .css_alloc = cgrp_css_alloc,
253 .css_online = cgrp_css_online,
254 .css_free = cgrp_css_free,
255 .attach = net_prio_attach,
256 .subsys_id = net_prio_subsys_id,
257 .base_cftypes = ss_files,
258 .module = THIS_MODULE,
259};
260
261static int netprio_device_event(struct notifier_block *unused,
262 unsigned long event, void *ptr)
263{
264 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
265 struct netprio_map *old;
266
267
268
269
270
271
272 switch (event) {
273 case NETDEV_UNREGISTER:
274 old = rtnl_dereference(dev->priomap);
275 RCU_INIT_POINTER(dev->priomap, NULL);
276 if (old)
277 kfree_rcu(old, rcu);
278 break;
279 }
280 return NOTIFY_DONE;
281}
282
283static struct notifier_block netprio_device_notifier = {
284 .notifier_call = netprio_device_event
285};
286
287static int __init init_cgroup_netprio(void)
288{
289 int ret;
290
291 ret = cgroup_load_subsys(&net_prio_subsys);
292 if (ret)
293 goto out;
294
295 register_netdevice_notifier(&netprio_device_notifier);
296
297out:
298 return ret;
299}
300
301static void __exit exit_cgroup_netprio(void)
302{
303 struct netprio_map *old;
304 struct net_device *dev;
305
306 unregister_netdevice_notifier(&netprio_device_notifier);
307
308 cgroup_unload_subsys(&net_prio_subsys);
309
310 rtnl_lock();
311 for_each_netdev(&init_net, dev) {
312 old = rtnl_dereference(dev->priomap);
313 RCU_INIT_POINTER(dev->priomap, NULL);
314 if (old)
315 kfree_rcu(old, rcu);
316 }
317 rtnl_unlock();
318}
319
320module_init(init_cgroup_netprio);
321module_exit(exit_cgroup_netprio);
322MODULE_LICENSE("GPL v2");
323