[RFC 1/2] misc: uidstat: Add uid stat driver to collect network statistics.

[Kiran Raparthy]

From: Mike Chan <mike@xxxxxxxxxxx>

misc: uidstat: Add uid stat driver to collect network statistics.

To analyze application's network statistics, we need a mechanism to export
the UID based statistics to userspace so that userspace tools can use the
exported numbers and generate the report against the UID.

This patch allows the user to explore the UID based network statistics
exported to /proc/uid_stat.

Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: Alexey Kuznetsov <kuznet@xxxxxxxxxxxxx>
Cc: James Morris <jmorris@xxxxxxxxx>
Cc: Hideaki YOSHIFUJI <yoshfuji@xxxxxxxxxxxxxx>
Cc: Patrick McHardy <kaber@xxxxxxxxx>
cc: Mike Chan <mike@xxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: netdev@xxxxxxxxxxxxxxx
Cc: Android Kernel Team <kernel-team@xxxxxxxxxxx>
Cc: John Stultz <john.stultz@xxxxxxxxxx>
Cc: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
Cc: JP Abgrall <jpa@xxxxxxxxxx>
Cc: Arve Hjøå<arve@xxxxxxxxxxx>
Signed-off-by: Mike Chan <mike@xxxxxxxxxxx>
[Kiran: Added context to commit message.
included build fixes from JP Abgrall and Arve.
Used single_release instead of seq_release.
internally continued to use uid_t but used covnersion
from kuid_t where ever necessary]
Signed-off-by: Kiran Raparthy <kiran.kumar@xxxxxxxxxx>
---
 drivers/misc/Kconfig     |   7 +++
 drivers/misc/Makefile    |   1 +
 drivers/misc/uid_stat.c  | 157 +++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/uid_stat.h |  33 ++++++++++
 net/ipv4/tcp.c           |  10 +++
 5 files changed, 208 insertions(+)
 create mode 100644 drivers/misc/uid_stat.c
 create mode 100644 include/linux/uid_stat.h

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 006242c..1c79b94 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -402,6 +402,13 @@ config TI_DAC7512
 	  This driver can also be built as a module. If so, the module
 	  will be called ti_dac7512.
 
+config UID_STAT
+	bool "UID based statistics tracking"
+	default n
+	help
+	  This option allows to enable UID based network statistics tracking.
+	  statistics are exported to /proc/uid_stat.
+
 config VMWARE_BALLOON
 	tristate "VMware Balloon Driver"
 	depends on X86 && HYPERVISOR_GUEST
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 7d5c4cd..3754347 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_ISL29020)		+= isl29020.o
 obj-$(CONFIG_SENSORS_TSL2550)	+= tsl2550.o
 obj-$(CONFIG_DS1682)		+= ds1682.o
 obj-$(CONFIG_TI_DAC7512)	+= ti_dac7512.o
+obj-$(CONFIG_UID_STAT)		+= uid_stat.o
 obj-$(CONFIG_C2PORT)		+= c2port/
 obj-$(CONFIG_HMC6352)		+= hmc6352.o
 obj-y				+= eeprom/
diff --git a/drivers/misc/uid_stat.c b/drivers/misc/uid_stat.c
new file mode 100644
index 0000000..aaaa406
--- /dev/null
+++ b/drivers/misc/uid_stat.c
@@ -0,0 +1,157 @@
+/* drivers/misc/uid_stat.c
+ *
+ * Copyright (C) 2008 - 2009 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/atomic.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/stat.h>
+#include <linux/uid_stat.h>
+
+static DEFINE_SPINLOCK(uid_lock);
+static LIST_HEAD(uid_list);
+static struct proc_dir_entry *parent;
+
+struct uid_stat {
+	struct list_head link;
+	uid_t uid;
+	atomic_t tcp_rcv;
+	atomic_t tcp_snd;
+};
+
+static struct uid_stat *find_uid_stat(uid_t uid)
+{
+	struct uid_stat *entry;
+
+	list_for_each_entry(entry, &uid_list, link) {
+		if (entry->uid == uid)
+			return entry;
+	}
+	return NULL;
+}
+
+static int uid_stat_atomic_int_show(struct seq_file *m, void *v)
+{
+	unsigned int bytes;
+	atomic_t *counter = m->private;
+
+	bytes = (unsigned int) (atomic_read(counter) + INT_MIN);
+	return seq_printf(m, "%u\n", bytes);
+}
+
+static int uid_stat_read_atomic_int_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, uid_stat_atomic_int_show, PDE_DATA(inode));
+}
+
+static const struct file_operations uid_stat_read_atomic_int_fops = {
+	.open		= uid_stat_read_atomic_int_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+/* Create a new entry for tracking the specified uid. */
+static struct uid_stat *create_stat(uid_t uid)
+{
+	struct uid_stat *new_uid;
+	/* Create the uid stat struct and append it to the list. */
+	new_uid = kmalloc(sizeof(struct uid_stat), GFP_ATOMIC);
+	if (!new_uid)
+		return NULL;
+
+	new_uid->uid = uid;
+	/* Counters start at INT_MIN, so we can track 4GB of network traffic. */
+	atomic_set(&new_uid->tcp_rcv, INT_MIN);
+	atomic_set(&new_uid->tcp_snd, INT_MIN);
+
+	list_add_tail(&new_uid->link, &uid_list);
+	return new_uid;
+}
+
+static void create_stat_proc(struct uid_stat *new_uid)
+{
+	char uid_s[32];
+	struct proc_dir_entry *entry;
+
+	sprintf(uid_s, "%d", new_uid->uid);
+	entry = proc_mkdir(uid_s, parent);
+
+	/* Keep reference to uid_stat so we know what uid to read stats from. */
+	proc_create_data("tcp_snd", S_IRUGO, entry,
+			 &uid_stat_read_atomic_int_fops, &new_uid->tcp_snd);
+
+	proc_create_data("tcp_rcv", S_IRUGO, entry,
+			 &uid_stat_read_atomic_int_fops, &new_uid->tcp_rcv);
+}
+
+static struct uid_stat *find_or_create_uid_stat(kuid_t uid)
+{
+	struct uid_stat *entry;
+	unsigned long flags;
+	uid_t proc_uid;
+
+	proc_uid = from_kuid(&init_user_ns, uid);
+	spin_lock_irqsave(&uid_lock, flags);
+	entry = find_uid_stat(proc_uid);
+	if (entry) {
+		spin_unlock_irqrestore(&uid_lock, flags);
+		return entry;
+	}
+	entry = create_stat(proc_uid);
+	spin_unlock_irqrestore(&uid_lock, flags);
+	if (entry)
+		create_stat_proc(entry);
+	return entry;
+}
+
+int uid_stat_tcp_snd(kuid_t uid, int size)
+{
+	struct uid_stat *entry;
+
+	entry = find_or_create_uid_stat(uid);
+	if (!entry)
+		return -1;
+	atomic_add(size, &entry->tcp_snd);
+	return 0;
+}
+
+int uid_stat_tcp_rcv(kuid_t uid, int size)
+{
+	struct uid_stat *entry;
+
+	entry = find_or_create_uid_stat(uid);
+	if (!entry)
+		return -1;
+	atomic_add(size, &entry->tcp_rcv);
+	return 0;
+}
+
+static int __init uid_stat_init(void)
+{
+	parent = proc_mkdir("uid_stat", NULL);
+	if (!parent) {
+		pr_err("uid_stat: failed to create proc entry\n");
+		return -1;
+	}
+	return 0;
+}
+
+device_initcall(uid_stat_init);
diff --git a/include/linux/uid_stat.h b/include/linux/uid_stat.h
new file mode 100644
index 0000000..68823d3
--- /dev/null
+++ b/include/linux/uid_stat.h
@@ -0,0 +1,33 @@
+/* include/linux/uid_stat.h
+ *
+ * Copyright (C) 2008-2009 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef __uid_stat_h
+#define __uid_stat_h
+
+/* Contains definitions for resource tracking per uid. */
+
+#ifdef CONFIG_UID_STAT
+int uid_stat_tcp_snd(kuid_t uid, int size);
+int uid_stat_tcp_rcv(kuid_t uid, int size);
+#else
+static inline int uid_stat_tcp_snd(kuid_t uid, int size)
+{
+}
+static inline int uid_stat_tcp_rcv(kuid_t uid, int size)
+{
+}
+#endif
+
+#endif /* _LINUX_UID_STAT_H */
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 3075723..00eb156 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -268,6 +268,7 @@
 #include <linux/crypto.h>
 #include <linux/time.h>
 #include <linux/slab.h>
+#include <linux/uid_stat.h>
 
 #include <net/icmp.h>
 #include <net/inet_common.h>
@@ -1280,6 +1281,9 @@ out:
 		tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
 out_nopush:
 	release_sock(sk);
+
+	if (copied + copied_syn)
+		uid_stat_tcp_snd(current_uid(), copied + copied_syn);
 	return copied + copied_syn;
 
 do_fault:
@@ -1551,6 +1555,7 @@ int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
 	if (copied > 0) {
 		tcp_recv_skb(sk, seq, &offset);
 		tcp_cleanup_rbuf(sk, copied);
+		uid_stat_tcp_rcv(current_uid(), copied);
 	}
 	return copied;
 }
@@ -1879,6 +1884,9 @@ skip_copy:
 	tcp_cleanup_rbuf(sk, copied);
 
 	release_sock(sk);
+
+	if (copied > 0)
+		uid_stat_tcp_rcv(current_uid(), copied);
 	return copied;
 
 out:
@@ -1887,6 +1895,8 @@ out:
 
 recv_urg:
 	err = tcp_recv_urg(sk, msg, len, flags);
+	if (err > 0)
+		uid_stat_tcp_rcv(current_uid(), err);
 	goto out;
 
 recv_sndq:
-- 
1.8.2.1

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