1 files changed, 152 insertions, 0 deletions
diff --git a/net/core/netclassid_cgroup.c b/net/core/netclassid_cgroup.c
new file mode 100644
index 000000000..41b24cd31
--- /dev/null
+++ b/net/core/netclassid_cgroup.c
@@ -0,0 +1,152 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * net/core/netclassid_cgroup.c	Classid Cgroupfs Handling
+ *
+ * Authors:	Thomas Graf <tgraf@suug.ch>
+ */
+
+#include <linux/slab.h>
+#include <linux/cgroup.h>
+#include <linux/fdtable.h>
+#include <linux/sched/task.h>
+
+#include <net/cls_cgroup.h>
+#include <net/sock.h>
+
+static inline struct cgroup_cls_state *css_cls_state(struct cgroup_subsys_state *css)
+{
+	return css ? container_of(css, struct cgroup_cls_state, css) : NULL;
+}
+
+struct cgroup_cls_state *task_cls_state(struct task_struct *p)
+{
+	return css_cls_state(task_css_check(p, net_cls_cgrp_id,
+					    rcu_read_lock_bh_held()));
+}
+EXPORT_SYMBOL_GPL(task_cls_state);
+
+static struct cgroup_subsys_state *
+cgrp_css_alloc(struct cgroup_subsys_state *parent_css)
+{
+	struct cgroup_cls_state *cs;
+
+	cs = kzalloc(sizeof(*cs), GFP_KERNEL);
+	if (!cs)
+		return ERR_PTR(-ENOMEM);
+
+	return &cs->css;
+}
+
+static int cgrp_css_online(struct cgroup_subsys_state *css)
+{
+	struct cgroup_cls_state *cs = css_cls_state(css);
+	struct cgroup_cls_state *parent = css_cls_state(css->parent);
+
+	if (parent)
+		cs->classid = parent->classid;
+
+	return 0;
+}
+
+static void cgrp_css_free(struct cgroup_subsys_state *css)
+{
+	kfree(css_cls_state(css));
+}
+
+/*
+ * To avoid freezing of sockets creation for tasks with big number of threads
+ * and opened sockets lets release file_lock every 1000 iterated descriptors.
+ * New sockets will already have been created with new classid.
+ */
+
+struct update_classid_context {
+	u32 classid;
+	unsigned int batch;
+};
+
+#define UPDATE_CLASSID_BATCH 1000
+
+static int update_classid_sock(const void *v, struct file *file, unsigned n)
+{
+	int err;
+	struct update_classid_context *ctx = (void *)v;
+	struct socket *sock = sock_from_file(file, &err);
+
+	if (sock) {
+		spin_lock(&cgroup_sk_update_lock);
+		sock_cgroup_set_classid(&sock->sk->sk_cgrp_data, ctx->classid);
+		spin_unlock(&cgroup_sk_update_lock);
+	}
+	if (--ctx->batch == 0) {
+		ctx->batch = UPDATE_CLASSID_BATCH;
+		return n + 1;
+	}
+	return 0;
+}
+
+static void update_classid_task(struct task_struct *p, u32 classid)
+{
+	struct update_classid_context ctx = {
+		.classid = classid,
+		.batch = UPDATE_CLASSID_BATCH
+	};
+	unsigned int fd = 0;
+
+	do {
+		task_lock(p);
+		fd = iterate_fd(p->files, fd, update_classid_sock, &ctx);
+		task_unlock(p);
+		cond_resched();
+	} while (fd);
+}
+
+static void cgrp_attach(struct cgroup_taskset *tset)
+{
+	struct cgroup_subsys_state *css;
+	struct task_struct *p;
+
+	cgroup_taskset_for_each(p, css, tset) {
+		update_classid_task(p, css_cls_state(css)->classid);
+	}
+}
+
+static u64 read_classid(struct cgroup_subsys_state *css, struct cftype *cft)
+{
+	return css_cls_state(css)->classid;
+}
+
+static int write_classid(struct cgroup_subsys_state *css, struct cftype *cft,
+			 u64 value)
+{
+	struct cgroup_cls_state *cs = css_cls_state(css);
+	struct css_task_iter it;
+	struct task_struct *p;
+
+	cgroup_sk_alloc_disable();
+
+	cs->classid = (u32)value;
+
+	css_task_iter_start(css, 0, &it);
+	while ((p = css_task_iter_next(&it)))
+		update_classid_task(p, cs->classid);
+	css_task_iter_end(&it);
+
+	return 0;
+}
+
+static struct cftype ss_files[] = {
+	{
+		.name		= "classid",
+		.read_u64	= read_classid,
+		.write_u64	= write_classid,
+	},
+	{ }	/* terminate */
+};
+
+struct cgroup_subsys net_cls_cgrp_subsys = {
+	.css_alloc		= cgrp_css_alloc,
+	.css_online		= cgrp_css_online,
+	.css_free		= cgrp_css_free,
+	.attach			= cgrp_attach,
+	.legacy_cftypes		= ss_files,
+};