1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * net/core/netclassid_cgroup.c Classid Cgroupfs Handling 4 * 5 * Authors: Thomas Graf <tgraf@suug.ch> 6 */ 7 8 #include <linux/slab.h> 9 #include <linux/cgroup.h> 10 #include <linux/fdtable.h> 11 #include <linux/sched/task.h> 12 13 #include <net/cls_cgroup.h> 14 #include <net/sock.h> 15 16 static inline struct cgroup_cls_state *css_cls_state(struct cgroup_subsys_state *css) 17 { 18 return css ? container_of(css, struct cgroup_cls_state, css) : NULL; 19 } 20 21 struct cgroup_cls_state *task_cls_state(struct task_struct *p) 22 { 23 return css_cls_state(task_css_check(p, net_cls_cgrp_id, 24 rcu_read_lock_bh_held())); 25 } 26 EXPORT_SYMBOL_GPL(task_cls_state); 27 28 static struct cgroup_subsys_state * 29 cgrp_css_alloc(struct cgroup_subsys_state *parent_css) 30 { 31 struct cgroup_cls_state *cs; 32 33 cs = kzalloc(sizeof(*cs), GFP_KERNEL); 34 if (!cs) 35 return ERR_PTR(-ENOMEM); 36 37 return &cs->css; 38 } 39 40 static int cgrp_css_online(struct cgroup_subsys_state *css) 41 { 42 struct cgroup_cls_state *cs = css_cls_state(css); 43 struct cgroup_cls_state *parent = css_cls_state(css->parent); 44 45 if (parent) 46 cs->classid = parent->classid; 47 48 return 0; 49 } 50 51 static void cgrp_css_free(struct cgroup_subsys_state *css) 52 { 53 kfree(css_cls_state(css)); 54 } 55 56 static int update_classid_sock(const void *v, struct file *file, unsigned n) 57 { 58 int err; 59 struct socket *sock = sock_from_file(file, &err); 60 61 if (sock) { 62 spin_lock(&cgroup_sk_update_lock); 63 sock_cgroup_set_classid(&sock->sk->sk_cgrp_data, 64 (unsigned long)v); 65 spin_unlock(&cgroup_sk_update_lock); 66 } 67 return 0; 68 } 69 70 static void cgrp_attach(struct cgroup_taskset *tset) 71 { 72 struct cgroup_subsys_state *css; 73 struct task_struct *p; 74 75 cgroup_taskset_for_each(p, css, tset) { 76 task_lock(p); 77 iterate_fd(p->files, 0, update_classid_sock, 78 (void *)(unsigned long)css_cls_state(css)->classid); 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 struct cgroup_cls_state *cs = css_cls_state(css); 92 struct css_task_iter it; 93 struct task_struct *p; 94 95 cgroup_sk_alloc_disable(); 96 97 cs->classid = (u32)value; 98 99 css_task_iter_start(css, 0, &it); 100 while ((p = css_task_iter_next(&it))) { 101 task_lock(p); 102 iterate_fd(p->files, 0, update_classid_sock, 103 (void *)(unsigned long)cs->classid); 104 task_unlock(p); 105 cond_resched(); 106 } 107 css_task_iter_end(&it); 108 109 return 0; 110 } 111 112 static struct cftype ss_files[] = { 113 { 114 .name = "classid", 115 .read_u64 = read_classid, 116 .write_u64 = write_classid, 117 }, 118 { } /* terminate */ 119 }; 120 121 struct cgroup_subsys net_cls_cgrp_subsys = { 122 .css_alloc = cgrp_css_alloc, 123 .css_online = cgrp_css_online, 124 .css_free = cgrp_css_free, 125 .attach = cgrp_attach, 126 .legacy_cftypes = ss_files, 127 }; 128