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_check(p, net_cls_cgrp_id, 27 rcu_read_lock_bh_held())); 28 } 29 EXPORT_SYMBOL_GPL(task_cls_state); 30 31 static struct cgroup_subsys_state * 32 cgrp_css_alloc(struct cgroup_subsys_state *parent_css) 33 { 34 struct cgroup_cls_state *cs; 35 36 cs = kzalloc(sizeof(*cs), GFP_KERNEL); 37 if (!cs) 38 return ERR_PTR(-ENOMEM); 39 40 return &cs->css; 41 } 42 43 static int cgrp_css_online(struct cgroup_subsys_state *css) 44 { 45 struct cgroup_cls_state *cs = css_cls_state(css); 46 struct cgroup_cls_state *parent = css_cls_state(css->parent); 47 48 if (parent) 49 cs->classid = parent->classid; 50 51 return 0; 52 } 53 54 static void cgrp_css_free(struct cgroup_subsys_state *css) 55 { 56 kfree(css_cls_state(css)); 57 } 58 59 static int update_classid(const void *v, struct file *file, unsigned n) 60 { 61 int err; 62 struct socket *sock = sock_from_file(file, &err); 63 64 if (sock) 65 sock->sk->sk_classid = (u32)(unsigned long)v; 66 67 return 0; 68 } 69 70 static void cgrp_attach(struct cgroup_subsys_state *css, 71 struct cgroup_taskset *tset) 72 { 73 struct cgroup_cls_state *cs = css_cls_state(css); 74 void *v = (void *)(unsigned long)cs->classid; 75 struct task_struct *p; 76 77 cgroup_taskset_for_each(p, tset) { 78 task_lock(p); 79 iterate_fd(p->files, 0, update_classid, v); 80 task_unlock(p); 81 } 82 } 83 84 static u64 read_classid(struct cgroup_subsys_state *css, struct cftype *cft) 85 { 86 return css_cls_state(css)->classid; 87 } 88 89 static int write_classid(struct cgroup_subsys_state *css, struct cftype *cft, 90 u64 value) 91 { 92 css_cls_state(css)->classid = (u32) value; 93 94 return 0; 95 } 96 97 static struct cftype ss_files[] = { 98 { 99 .name = "classid", 100 .read_u64 = read_classid, 101 .write_u64 = write_classid, 102 }, 103 { } /* terminate */ 104 }; 105 106 struct cgroup_subsys net_cls_cgrp_subsys = { 107 .css_alloc = cgrp_css_alloc, 108 .css_online = cgrp_css_online, 109 .css_free = cgrp_css_free, 110 .attach = cgrp_attach, 111 .legacy_cftypes = ss_files, 112 }; 113