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/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/cgroup.h>
  15 #include <linux/fdtable.h>
  16 #include <net/cls_cgroup.h>
  17 #include <net/sock.h>
  18
  19 static inline struct cgroup_cls_state *css_cls_state(struct cgroup_subsys_state *css)
  20 {
  21         return css ? container_of(css, struct cgroup_cls_state, css) : NULL;
  22 }
  23
  24 struct cgroup_cls_state *task_cls_state(struct task_struct *p)
  25 {
  26         return css_cls_state(task_css(p, net_cls_cgrp_id));
  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(css));
  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(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                 sock->sk->sk_classid = (u32)(unsigned long)v;
  65
  66         return 0;
  67 }
  68
  69 static void cgrp_attach(struct cgroup_subsys_state *css,
  70                         struct cgroup_taskset *tset)
  71 {
  72         struct cgroup_cls_state *cs = css_cls_state(css);
  73         void *v = (void *)(unsigned long)cs->classid;
  74         struct task_struct *p;
  75
  76         cgroup_taskset_for_each(p, tset) {
  77                 task_lock(p);
  78                 iterate_fd(p->files, 0, update_classid, v);
  79                 task_unlock(p);
  80         }
  81 }
  82
  83 static u64 read_classid(struct cgroup_subsys_state *css, struct cftype *cft)
  84 {
  85         return css_cls_state(css)->classid;
  86 }
  87
  88 static int write_classid(struct cgroup_subsys_state *css, struct cftype *cft,
  89                          u64 value)
  90 {
  91         css_cls_state(css)->classid = (u32) value;
  92
  93         return 0;
  94 }
  95
  96 static struct cftype ss_files[] = {
  97         {
  98                 .name           = "classid",
  99                 .read_u64       = read_classid,
 100                 .write_u64      = write_classid,
 101         },
 102         { }     /* terminate */
 103 };
 104
 105 struct cgroup_subsys net_cls_cgrp_subsys = {
 106         .css_alloc              = cgrp_css_alloc,
 107         .css_online             = cgrp_css_online,
 108         .css_free               = cgrp_css_free,
 109         .attach                 = cgrp_attach,
 110         .base_cftypes           = ss_files,
 111 };