net/core/netclassid_cgroup.c

   1 /*
   2  * net/core/netclassid_cgroup.c Classid Cgroupfs Handling
   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/slab.h>
  13 #include <linux/cgroup.h>
  14 #include <linux/fdtable.h>
  15 #include <net/cls_cgroup.h>
  16 #include <net/sock.h>
  17
  18 static inline struct cgroup_cls_state *css_cls_state(struct cgroup_subsys_state *css)
  19 {
  20         return css ? container_of(css, struct cgroup_cls_state, css) : NULL;
  21 }
  22
  23 struct cgroup_cls_state *task_cls_state(struct task_struct *p)
  24 {
  25         return css_cls_state(task_css_check(p, net_cls_cgrp_id,
  26                                             rcu_read_lock_bh_held()));
  27 }
  28 EXPORT_SYMBOL_GPL(task_cls_state);
  29
  30 static struct cgroup_subsys_state *
  31 cgrp_css_alloc(struct cgroup_subsys_state *parent_css)
  32 {
  33         struct cgroup_cls_state *cs;
  34
  35         cs = kzalloc(sizeof(*cs), GFP_KERNEL);
  36         if (!cs)
  37                 return ERR_PTR(-ENOMEM);
  38
  39         return &cs->css;
  40 }
  41
  42 static int cgrp_css_online(struct cgroup_subsys_state *css)
  43 {
  44         struct cgroup_cls_state *cs = css_cls_state(css);
  45         struct cgroup_cls_state *parent = css_cls_state(css->parent);
  46
  47         if (parent)
  48                 cs->classid = parent->classid;
  49
  50         return 0;
  51 }
  52
  53 static void cgrp_css_free(struct cgroup_subsys_state *css)
  54 {
  55         kfree(css_cls_state(css));
  56 }
  57
  58 static int update_classid_sock(const void *v, struct file *file, unsigned n)
  59 {
  60         int err;
  61         struct socket *sock = sock_from_file(file, &err);
  62
  63         if (sock) {
  64                 spin_lock(&cgroup_sk_update_lock);
  65                 sock_cgroup_set_classid(&sock->sk->sk_cgrp_data,
  66                                         (unsigned long)v);
  67                 spin_unlock(&cgroup_sk_update_lock);
  68         }
  69         return 0;
  70 }
  71
  72 static void cgrp_attach(struct cgroup_taskset *tset)
  73 {
  74         struct cgroup_subsys_state *css;
  75         struct task_struct *p;
  76
  77         cgroup_taskset_for_each(p, css, tset) {
  78                 task_lock(p);
  79                 iterate_fd(p->files, 0, update_classid_sock,
  80                            (void *)(unsigned long)css_cls_state(css)->classid);
  81                 task_unlock(p);
  82         }
  83 }
  84
  85 static u64 read_classid(struct cgroup_subsys_state *css, struct cftype *cft)
  86 {
  87         return css_cls_state(css)->classid;
  88 }
  89
  90 static int write_classid(struct cgroup_subsys_state *css, struct cftype *cft,
  91                          u64 value)
  92 {
  93         struct cgroup_cls_state *cs = css_cls_state(css);
  94         struct css_task_iter it;
  95         struct task_struct *p;
  96
  97         cgroup_sk_alloc_disable();
  98
  99         cs->classid = (u32)value;
 100
 101         css_task_iter_start(css, &it);
 102         while ((p = css_task_iter_next(&it))) {
 103                 task_lock(p);
 104                 iterate_fd(p->files, 0, update_classid_sock,
 105                            (void *)(unsigned long)cs->classid);
 106                 task_unlock(p);
 107         }
 108         css_task_iter_end(&it);
 109
 110         return 0;
 111 }
 112
 113 static struct cftype ss_files[] = {
 114         {
 115                 .name           = "classid",
 116                 .read_u64       = read_classid,
 117                 .write_u64      = write_classid,
 118         },
 119         { }     /* terminate */
 120 };
 121
 122 struct cgroup_subsys net_cls_cgrp_subsys = {
 123         .css_alloc              = cgrp_css_alloc,
 124         .css_online             = cgrp_css_online,
 125         .css_free               = cgrp_css_free,
 126         .attach                 = cgrp_attach,
 127         .legacy_cftypes         = ss_files,
 128 };