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); 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 .legacy_cftypes = ss_files, 111 }; 112