155 lines
3.4 KiB
C
155 lines
3.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* net/core/netclassid_cgroup.c Classid Cgroupfs Handling
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*
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* Authors: Thomas Graf <tgraf@suug.ch>
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*/
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#include <linux/slab.h>
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#include <linux/cgroup.h>
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#include <linux/fdtable.h>
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#include <linux/sched/task.h>
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#include <net/cls_cgroup.h>
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#include <net/sock.h>
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static inline struct cgroup_cls_state *css_cls_state(struct cgroup_subsys_state *css)
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{
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return css ? container_of(css, struct cgroup_cls_state, css) : NULL;
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}
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struct cgroup_cls_state *task_cls_state(struct task_struct *p)
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{
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return css_cls_state(task_css_check(p, net_cls_cgrp_id,
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rcu_read_lock_bh_held()));
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}
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EXPORT_SYMBOL_GPL(task_cls_state);
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static struct cgroup_subsys_state *
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cgrp_css_alloc(struct cgroup_subsys_state *parent_css)
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{
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struct cgroup_cls_state *cs;
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cs = kzalloc(sizeof(*cs), GFP_KERNEL);
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if (!cs)
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return ERR_PTR(-ENOMEM);
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return &cs->css;
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}
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static int cgrp_css_online(struct cgroup_subsys_state *css)
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{
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struct cgroup_cls_state *cs = css_cls_state(css);
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struct cgroup_cls_state *parent = css_cls_state(css->parent);
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if (parent)
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cs->classid = parent->classid;
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return 0;
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}
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static void cgrp_css_free(struct cgroup_subsys_state *css)
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{
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kfree(css_cls_state(css));
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}
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/*
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* To avoid freezing of sockets creation for tasks with big number of threads
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* and opened sockets lets release file_lock every 1000 iterated descriptors.
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* New sockets will already have been created with new classid.
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*/
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struct update_classid_context {
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u32 classid;
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unsigned int batch;
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};
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#define UPDATE_CLASSID_BATCH 1000
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static int update_classid_sock(const void *v, struct file *file, unsigned n)
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{
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int err;
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struct update_classid_context *ctx = (void *)v;
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struct socket *sock = sock_from_file(file, &err);
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if (sock) {
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spin_lock(&cgroup_sk_update_lock);
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sock_cgroup_set_classid(&sock->sk->sk_cgrp_data, ctx->classid);
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spin_unlock(&cgroup_sk_update_lock);
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}
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if (--ctx->batch == 0) {
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ctx->batch = UPDATE_CLASSID_BATCH;
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return n + 1;
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}
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return 0;
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}
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static void update_classid_task(struct task_struct *p, u32 classid)
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{
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struct update_classid_context ctx = {
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.classid = classid,
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.batch = UPDATE_CLASSID_BATCH
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};
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unsigned int fd = 0;
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do {
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task_lock(p);
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fd = iterate_fd(p->files, fd, update_classid_sock, &ctx);
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task_unlock(p);
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cond_resched();
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} while (fd);
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}
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static void cgrp_attach(struct cgroup_taskset *tset)
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{
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struct cgroup_subsys_state *css;
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struct task_struct *p;
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cgroup_taskset_for_each(p, css, tset) {
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update_classid_task(p, css_cls_state(css)->classid);
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}
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}
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static u64 read_classid(struct cgroup_subsys_state *css, struct cftype *cft)
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{
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return css_cls_state(css)->classid;
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}
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static int write_classid(struct cgroup_subsys_state *css, struct cftype *cft,
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u64 value)
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{
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struct cgroup_cls_state *cs = css_cls_state(css);
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struct css_task_iter it;
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struct task_struct *p;
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cgroup_sk_alloc_disable();
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cs->classid = (u32)value;
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css_task_iter_start(css, 0, &it);
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while ((p = css_task_iter_next(&it))) {
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update_classid_task(p, cs->classid);
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cond_resched();
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}
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css_task_iter_end(&it);
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return 0;
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}
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static struct cftype ss_files[] = {
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{
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.name = "classid",
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.read_u64 = read_classid,
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.write_u64 = write_classid,
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},
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{ } /* terminate */
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};
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struct cgroup_subsys net_cls_cgrp_subsys = {
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.css_alloc = cgrp_css_alloc,
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.css_online = cgrp_css_online,
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.css_free = cgrp_css_free,
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.attach = cgrp_attach,
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.legacy_cftypes = ss_files,
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};
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