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 <linux/sched/task.h> 16 17 #include <net/cls_cgroup.h> 18 #include <net/sock.h> 19 20 static inline struct cgroup_cls_state *css_cls_state(struct cgroup_subsys_state *css) 21 { 22 return css ? container_of(css, struct cgroup_cls_state, css) : NULL; 23 } 24 25 struct cgroup_cls_state *task_cls_state(struct task_struct *p) 26 { 27 return css_cls_state(task_css_check(p, net_cls_cgrp_id, 28 rcu_read_lock_bh_held())); 29 } 30 EXPORT_SYMBOL_GPL(task_cls_state); 31 32 static struct cgroup_subsys_state * 33 cgrp_css_alloc(struct cgroup_subsys_state *parent_css) 34 { 35 struct cgroup_cls_state *cs; 36 37 cs = kzalloc(sizeof(*cs), GFP_KERNEL); 38 if (!cs) 39 return ERR_PTR(-ENOMEM); 40 41 return &cs->css; 42 } 43 44 static int cgrp_css_online(struct cgroup_subsys_state *css) 45 { 46 struct cgroup_cls_state *cs = css_cls_state(css); 47 struct cgroup_cls_state *parent = css_cls_state(css->parent); 48 49 if (parent) 50 cs->classid = parent->classid; 51 52 return 0; 53 } 54 55 static void cgrp_css_free(struct cgroup_subsys_state *css) 56 { 57 kfree(css_cls_state(css)); 58 } 59 60 static int update_classid_sock(const void *v, struct file *file, unsigned n) 61 { 62 int err; 63 struct socket *sock = sock_from_file(file, &err); 64 65 if (sock) { 66 spin_lock(&cgroup_sk_update_lock); 67 sock_cgroup_set_classid(&sock->sk->sk_cgrp_data, 68 (unsigned long)v); 69 spin_unlock(&cgroup_sk_update_lock); 70 } 71 return 0; 72 } 73 74 static void cgrp_attach(struct cgroup_taskset *tset) 75 { 76 struct cgroup_subsys_state *css; 77 struct task_struct *p; 78 79 cgroup_taskset_for_each(p, css, tset) { 80 task_lock(p); 81 iterate_fd(p->files, 0, update_classid_sock, 82 (void *)(unsigned long)css_cls_state(css)->classid); 83 task_unlock(p); 84 } 85 } 86 87 static u64 read_classid(struct cgroup_subsys_state *css, struct cftype *cft) 88 { 89 return css_cls_state(css)->classid; 90 } 91 92 static int write_classid(struct cgroup_subsys_state *css, struct cftype *cft, 93 u64 value) 94 { 95 struct cgroup_cls_state *cs = css_cls_state(css); 96 struct css_task_iter it; 97 struct task_struct *p; 98 99 cgroup_sk_alloc_disable(); 100 101 cs->classid = (u32)value; 102 103 css_task_iter_start(css, 0, &it); 104 while ((p = css_task_iter_next(&it))) { 105 task_lock(p); 106 iterate_fd(p->files, 0, update_classid_sock, 107 (void *)(unsigned long)cs->classid); 108 task_unlock(p); 109 } 110 css_task_iter_end(&it); 111 112 return 0; 113 } 114 115 static struct cftype ss_files[] = { 116 { 117 .name = "classid", 118 .read_u64 = read_classid, 119 .write_u64 = write_classid, 120 }, 121 { } /* terminate */ 122 }; 123 124 struct cgroup_subsys net_cls_cgrp_subsys = { 125 .css_alloc = cgrp_css_alloc, 126 .css_online = cgrp_css_online, 127 .css_free = cgrp_css_free, 128 .attach = cgrp_attach, 129 .legacy_cftypes = ss_files, 130 }; 131