Release 4.11 net/netfilter/xt_recent.c

/*
 * Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
 * Copyright © CC Computer Consultants GmbH, 2007 - 2008
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This is a replacement of the old ipt_recent module, which carried the
 * following copyright notice:
 *
 * Author: Stephen Frost <sfrost@snowman.net>
 * Copyright 2002-2003, Stephen Frost, 2.5.x port by laforge@netfilter.org
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/list.h>
#include <linux/random.h>
#include <linux/jhash.h>
#include <linux/bitops.h>
#include <linux/skbuff.h>
#include <linux/inet.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>

#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_recent.h>

MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
MODULE_DESCRIPTION("Xtables: \"recently-seen\" host matching");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_recent");
MODULE_ALIAS("ip6t_recent");


static unsigned int ip_list_tot __read_mostly = 100;

static unsigned int ip_list_hash_size __read_mostly;

static unsigned int ip_list_perms __read_mostly = 0644;

static unsigned int ip_list_uid __read_mostly;

static unsigned int ip_list_gid __read_mostly;
module_param(ip_list_tot, uint, 0400);
module_param(ip_list_hash_size, uint, 0400);
module_param(ip_list_perms, uint, 0400);
module_param(ip_list_uid, uint, S_IRUGO | S_IWUSR);
module_param(ip_list_gid, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(ip_list_tot, "number of IPs to remember per list");
MODULE_PARM_DESC(ip_list_hash_size, "size of hash table used to look up IPs");
MODULE_PARM_DESC(ip_list_perms, "permissions on /proc/net/xt_recent/* files");
MODULE_PARM_DESC(ip_list_uid, "default owner of /proc/net/xt_recent/* files");
MODULE_PARM_DESC(ip_list_gid, "default owning group of /proc/net/xt_recent/* files");

/* retained for backwards compatibility */

static unsigned int ip_pkt_list_tot __read_mostly;
module_param(ip_pkt_list_tot, uint, 0400);
MODULE_PARM_DESC(ip_pkt_list_tot, "number of packets per IP address to remember (max. 255)");


#define XT_RECENT_MAX_NSTAMPS	256


struct recent_entry {
	
struct list_head	list;
	
struct list_head	lru_list;
	
union nf_inet_addr	addr;
	
u_int16_t		family;
	
u_int8_t		ttl;
	
u_int8_t		index;
	
u_int16_t		nstamps;
	
unsigned long		stamps[0];
};


struct recent_table {
	
struct list_head	list;
	
char			name[XT_RECENT_NAME_LEN];
	
union nf_inet_addr	mask;
	
unsigned int		refcnt;
	
unsigned int		entries;
	
u8			nstamps_max_mask;
	
struct list_head	lru_list;
	
struct list_head	iphash[0];
};


struct recent_net {
	
struct list_head	tables;
#ifdef CONFIG_PROC_FS
	
struct proc_dir_entry	*xt_recent;
#endif
};


static unsigned int recent_net_id __read_mostly;



static inline struct recent_net *recent_pernet(struct net *net)
{
	return net_generic(net, recent_net_id);
}

Contributors
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Alexey Dobriyan
19
86.36%
1
33.33%
Patrick McHardy
2
9.09%
1
33.33%
Stephen Frost
1
4.55%
1
33.33%
Total
22
100.00%
3
100.00%

static DEFINE_SPINLOCK(recent_lock);
static DEFINE_MUTEX(recent_mutex);

#ifdef CONFIG_PROC_FS


static const struct file_operations recent_old_fops, recent_mt_fops;
#endif


static u_int32_t hash_rnd __read_mostly;



static inline unsigned int recent_entry_hash4(const union nf_inet_addr *addr)
{
	return jhash_1word((__force u32)addr->ip, hash_rnd) &
	       (ip_list_hash_size - 1);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Jan Engelhardt
19
55.88%
2
40.00%
Patrick McHardy
10
29.41%
1
20.00%
Al Viro
4
11.76%
1
20.00%
Stephen Frost
1
2.94%
1
20.00%
Total
34
100.00%
5
100.00%



static inline unsigned int recent_entry_hash6(const union nf_inet_addr *addr)
{
	return jhash2((u32 *)addr->ip6, ARRAY_SIZE(addr->ip6), hash_rnd) &
	       (ip_list_hash_size - 1);
}

Contributors
Person
Tokens
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CommitProp
Jan Engelhardt
30
73.17%
2
66.67%
Patrick McHardy
11
26.83%
1
33.33%
Total
41
100.00%
3
100.00%


static struct recent_entry *

recent_entry_lookup(const struct recent_table *table,
		    const union nf_inet_addr *addrp, u_int16_t family,
		    u_int8_t ttl)
{
	struct recent_entry *e;
	unsigned int h;

	if (family == NFPROTO_IPV4)
		h = recent_entry_hash4(addrp);
	else
		h = recent_entry_hash6(addrp);

	list_for_each_entry(e, &table->iphash[h], list)
		if (e->family == family &&
		    memcmp(&e->addr, addrp, sizeof(e->addr)) == 0 &&
		    (ttl == e->ttl || ttl == 0 || e->ttl == 0))
			return e;
	return NULL;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Jan Engelhardt
48
41.74%
2
50.00%
Patrick McHardy
45
39.13%
1
25.00%
Stephen Frost
22
19.13%
1
25.00%
Total
115
100.00%
4
100.00%



static void recent_entry_remove(struct recent_table *t, struct recent_entry *e)
{
	list_del(&e->list);
	list_del(&e->lru_list);
	kfree(e);
	t->entries--;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Patrick McHardy
29
69.05%
1
50.00%
Stephen Frost
13
30.95%
1
50.00%
Total
42
100.00%
2
100.00%

/*
 * Drop entries with timestamps older then 'time'.
 */


static void recent_entry_reap(struct recent_table *t, unsigned long time)
{
	struct recent_entry *e;

	/*
         * The head of the LRU list is always the oldest entry.
         */
	e = list_entry(t->lru_list.next, struct recent_entry, lru_list);

	/*
         * The last time stamp is the most recent.
         */
	if (time_after(time, e->stamps[e->index-1]))
		recent_entry_remove(t, e);
}

Contributors
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Tim Gardner
63
100.00%
1
100.00%
Total
63
100.00%
1
100.00%


static struct recent_entry *

recent_entry_init(struct recent_table *t, const union nf_inet_addr *addr,
		  u_int16_t family, u_int8_t ttl)
{
	struct recent_entry *e;
	unsigned int nstamps_max = t->nstamps_max_mask;

	if (t->entries >= ip_list_tot) {
		e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
		recent_entry_remove(t, e);
	}

	nstamps_max += 1;
	e = kmalloc(sizeof(*e) + sizeof(e->stamps[0]) * nstamps_max,
		    GFP_ATOMIC);
	if (e == NULL)
		return NULL;
	memcpy(&e->addr, addr, sizeof(e->addr));
	e->ttl       = ttl;
	e->stamps[0] = jiffies;
	e->nstamps   = 1;
	e->index     = 1;
	e->family    = family;
	if (family == NFPROTO_IPV4)
		list_add_tail(&e->list, &t->iphash[recent_entry_hash4(addr)]);
	else
		list_add_tail(&e->list, &t->iphash[recent_entry_hash6(addr)]);
	list_add_tail(&e->lru_list, &t->lru_list);
	t->entries++;
	return e;
}

Contributors
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CommitProp
Patrick McHardy
118
52.44%
1
20.00%
Jan Engelhardt
52
23.11%
2
40.00%
Stephen Frost
42
18.67%
1
20.00%
Florian Westphal
13
5.78%
1
20.00%
Total
225
100.00%
5
100.00%



static void recent_entry_update(struct recent_table *t, struct recent_entry *e)
{
	e->index &= t->nstamps_max_mask;
	e->stamps[e->index++] = jiffies;
	if (e->index > e->nstamps)
		e->nstamps = e->index;
	list_move_tail(&e->lru_list, &t->lru_list);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Patrick McHardy
49
73.13%
1
25.00%
Stephen Frost
10
14.93%
1
25.00%
Tim Gardner
4
5.97%
1
25.00%
Florian Westphal
4
5.97%
1
25.00%
Total
67
100.00%
4
100.00%



static struct recent_table *recent_table_lookup(struct recent_net *recent_net,
						const char *name)
{
	struct recent_table *t;

	list_for_each_entry(t, &recent_net->tables, list)
		if (!strcmp(t->name, name))
			return t;
	return NULL;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Patrick McHardy
35
71.43%
1
33.33%
Stephen Frost
8
16.33%
1
33.33%
Alexey Dobriyan
6
12.24%
1
33.33%
Total
49
100.00%
3
100.00%



static void recent_table_flush(struct recent_table *t)
{
	struct recent_entry *e, *next;
	unsigned int i;

	for (i = 0; i < ip_list_hash_size; i++)
		list_for_each_entry_safe(e, next, &t->iphash[i], list)
			recent_entry_remove(t, e);
}

Contributors
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Patrick McHardy
53
100.00%
1
100.00%
Total
53
100.00%
1
100.00%


static bool

recent_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
	struct net *net = xt_net(par);
	struct recent_net *recent_net = recent_pernet(net);
	const struct xt_recent_mtinfo_v1 *info = par->matchinfo;
	struct recent_table *t;
	struct recent_entry *e;
	union nf_inet_addr addr = {}, addr_mask;
	u_int8_t ttl;
	bool ret = info->invert;

	if (xt_family(par) == NFPROTO_IPV4) {
		const struct iphdr *iph = ip_hdr(skb);

		if (info->side == XT_RECENT_DEST)
			addr.ip = iph->daddr;
		else
			addr.ip = iph->saddr;

		ttl = iph->ttl;
	} else {
		const struct ipv6hdr *iph = ipv6_hdr(skb);

		if (info->side == XT_RECENT_DEST)
			memcpy(&addr.in6, &iph->daddr, sizeof(addr.in6));
		else
			memcpy(&addr.in6, &iph->saddr, sizeof(addr.in6));

		ttl = iph->hop_limit;
	}

	/* use TTL as seen before forwarding */
	if (xt_out(par) != NULL && skb->sk == NULL)
		ttl++;

	spin_lock_bh(&recent_lock);
	t = recent_table_lookup(recent_net, info->name);

	nf_inet_addr_mask(&addr, &addr_mask, &t->mask);

	e = recent_entry_lookup(t, &addr_mask, xt_family(par),
				(info->check_set & XT_RECENT_TTL) ? ttl : 0);
	if (e == NULL) {
		if (!(info->check_set & XT_RECENT_SET))
			goto out;
		e = recent_entry_init(t, &addr_mask, xt_family(par), ttl);
		if (e == NULL)
			par->hotdrop = true;
		ret = !ret;
		goto out;
	}

	if (info->check_set & XT_RECENT_SET)
		ret = !ret;
	else if (info->check_set & XT_RECENT_REMOVE) {
		recent_entry_remove(t, e);
		ret = !ret;
	} else if (info->check_set & (XT_RECENT_CHECK | XT_RECENT_UPDATE)) {
		unsigned long time = jiffies - info->seconds * HZ;
		unsigned int i, hits = 0;

		for (i = 0; i < e->nstamps; i++) {
			if (info->seconds && time_after(time, e->stamps[i]))
				continue;
			if (!info->hit_count || ++hits >= info->hit_count) {
				ret = !ret;
				break;
			}
		}

		/* info->seconds must be non-zero */
		if (info->check_set & XT_RECENT_REAP)
			recent_entry_reap(t, time);
	}

	if (info->check_set & XT_RECENT_SET ||
	    (info->check_set & XT_RECENT_UPDATE && ret)) {
		recent_entry_update(t, e);
		e->ttl = ttl;
	}
out:
	spin_unlock_bh(&recent_lock);
	return ret;
}

Contributors
Person
Tokens
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Commits
CommitProp
Patrick McHardy
205
39.27%
3
16.67%
Jan Engelhardt
145
27.78%
8
44.44%
Stephen Frost
98
18.77%
1
5.56%
Tim Gardner
19
3.64%
2
11.11%
Alexey Dobriyan
19
3.64%
1
5.56%
Denys Fedoryshchenko
19
3.64%
1
5.56%
Pablo Neira Ayuso
15
2.87%
1
5.56%
David S. Miller
2
0.38%
1
5.56%
Total
522
100.00%
18
100.00%



static void recent_table_free(void *addr)
{
	kvfree(addr);
}

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Eric Dumazet
14
93.33%
1
50.00%
Américo Wang
1
6.67%
1
50.00%
Total
15
100.00%
2
100.00%



static int recent_mt_check(const struct xt_mtchk_param *par,
			   const struct xt_recent_mtinfo_v1 *info)
{
	struct recent_net *recent_net = recent_pernet(par->net);
	struct recent_table *t;
#ifdef CONFIG_PROC_FS
	struct proc_dir_entry *pde;
	kuid_t uid;
	kgid_t gid;
#endif
	unsigned int nstamp_mask;
	unsigned int i;
	int ret = -EINVAL;
	size_t sz;

	net_get_random_once(&hash_rnd, sizeof(hash_rnd));

	if (info->check_set & ~XT_RECENT_VALID_FLAGS) {
		pr_info("Unsupported user space flags (%08x)\n",
			info->check_set);
		return -EINVAL;
	}
	if (hweight8(info->check_set &
		     (XT_RECENT_SET | XT_RECENT_REMOVE |
		      XT_RECENT_CHECK | XT_RECENT_UPDATE)) != 1)
		return -EINVAL;
	if ((info->check_set & (XT_RECENT_SET | XT_RECENT_REMOVE)) &&
	    (info->seconds || info->hit_count ||
	    (info->check_set & XT_RECENT_MODIFIERS)))
		return -EINVAL;
	if ((info->check_set & XT_RECENT_REAP) && !info->seconds)
		return -EINVAL;
	if (info->hit_count >= XT_RECENT_MAX_NSTAMPS) {
		pr_info("hitcount (%u) is larger than allowed maximum (%u)\n",
			info->hit_count, XT_RECENT_MAX_NSTAMPS - 1);
		return -EINVAL;
	}
	if (info->name[0] == '\0' ||
	    strnlen(info->name, XT_RECENT_NAME_LEN) == XT_RECENT_NAME_LEN)
		return -EINVAL;

	if (ip_pkt_list_tot && info->hit_count < ip_pkt_list_tot)
		nstamp_mask = roundup_pow_of_two(ip_pkt_list_tot) - 1;
	else if (info->hit_count)
		nstamp_mask = roundup_pow_of_two(info->hit_count) - 1;
	else
		nstamp_mask = 32 - 1;

	mutex_lock(&recent_mutex);
	t = recent_table_lookup(recent_net, info->name);
	if (t != NULL) {
		if (nstamp_mask > t->nstamps_max_mask) {
			spin_lock_bh(&recent_lock);
			recent_table_flush(t);
			t->nstamps_max_mask = nstamp_mask;
			spin_unlock_bh(&recent_lock);
		}

		t->refcnt++;
		ret = 0;
		goto out;
	}

	sz = sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size;
	if (sz <= PAGE_SIZE)
		t = kzalloc(sz, GFP_KERNEL);
	else
		t = vzalloc(sz);
	if (t == NULL) {
		ret = -ENOMEM;
		goto out;
	}
	t->refcnt = 1;
	t->nstamps_max_mask = nstamp_mask;

	memcpy(&t->mask, &info->mask, sizeof(t->mask));
	strcpy(t->name, info->name);
	INIT_LIST_HEAD(&t->lru_list);
	for (i = 0; i < ip_list_hash_size; i++)
		INIT_LIST_HEAD(&t->iphash[i]);
#ifdef CONFIG_PROC_FS
	uid = make_kuid(&init_user_ns, ip_list_uid);
	gid = make_kgid(&init_user_ns, ip_list_gid);
	if (!uid_valid(uid) || !gid_valid(gid)) {
		recent_table_free(t);
		ret = -EINVAL;
		goto out;
	}
	pde = proc_create_data(t->name, ip_list_perms, recent_net->xt_recent,
		  &recent_mt_fops, t);
	if (pde == NULL) {
		recent_table_free(t);
		ret = -ENOMEM;
		goto out;
	}
	proc_set_user(pde, uid, gid);
#endif
	spin_lock_bh(&recent_lock);
	list_add_tail(&t->list, &recent_net->tables);
	spin_unlock_bh(&recent_lock);
	ret = 0;
out:
	mutex_unlock(&recent_mutex);
	return ret;
}

Contributors
Person
Tokens
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CommitProp
Patrick McHardy
162
25.80%
4
13.33%
Stephen Frost
100
15.92%
1
3.33%
Florian Westphal
93
14.81%
2
6.67%
Jan Engelhardt
66
10.51%
10
33.33%
Eric W. Biedermann
56
8.92%
1
3.33%
Tim Gardner
46
7.32%
2
6.67%
Alexey Dobriyan
36
5.73%
3
10.00%
Eric Dumazet
27
4.30%
2
6.67%
Denys Fedoryshchenko
26
4.14%
1
3.33%
Daniel Hokka Zakrisson
8
1.27%
1
3.33%
David Howells
5
0.80%
1
3.33%
Denis V. Lunev
2
0.32%
1
3.33%
Gao Feng
1
0.16%
1
3.33%
Total
628
100.00%
30
100.00%



static int recent_mt_check_v0(const struct xt_mtchk_param *par)
{
	const struct xt_recent_mtinfo_v0 *info_v0 = par->matchinfo;
	struct xt_recent_mtinfo_v1 info_v1;

	/* Copy revision 0 structure to revision 1 */
	memcpy(&info_v1, info_v0, sizeof(struct xt_recent_mtinfo));
	/* Set default mask to ensure backward compatible behaviour */
	memset(info_v1.mask.all, 0xFF, sizeof(info_v1.mask.all));

	return recent_mt_check(par, &info_v1);
}

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Denys Fedoryshchenko
71
100.00%
1
100.00%
Total
71
100.00%
1
100.00%



static int recent_mt_check_v1(const struct xt_mtchk_param *par)
{
	return recent_mt_check(par, par->matchinfo);
}

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Denys Fedoryshchenko
22
100.00%
1
100.00%
Total
22
100.00%
1
100.00%



static void recent_mt_destroy(const struct xt_mtdtor_param *par)
{
	struct recent_net *recent_net = recent_pernet(par->net);
	const struct xt_recent_mtinfo_v1 *info = par->matchinfo;
	struct recent_table *t;

	mutex_lock(&recent_mutex);
	t = recent_table_lookup(recent_net, info->name);
	if (--t->refcnt == 0) {
		spin_lock_bh(&recent_lock);
		list_del(&t->list);
		spin_unlock_bh(&recent_lock);
#ifdef CONFIG_PROC_FS
		if (recent_net->xt_recent != NULL)
			remove_proc_entry(t->name, recent_net->xt_recent);
#endif
		recent_table_flush(t);
		recent_table_free(t);
	}
	mutex_unlock(&recent_mutex);
}

Contributors
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CommitProp
Patrick McHardy
61
48.03%
2
18.18%
Stephen Frost
23
18.11%
1
9.09%
Alexey Dobriyan
17
13.39%
1
9.09%
Jan Engelhardt
11
8.66%
3
27.27%
Vitaly E. Lavrov
8
6.30%
1
9.09%
Pavel Emelyanov
5
3.94%
1
9.09%
Eric Dumazet
1
0.79%
1
9.09%
Denys Fedoryshchenko
1
0.79%
1
9.09%
Total
127
100.00%
11
100.00%

#ifdef CONFIG_PROC_FS

struct recent_iter_state {
	
const struct recent_table *table;
	
unsigned int		bucket;
};


static void *recent_seq_start(struct seq_file *seq, loff_t *pos)
	__acquires
(recent_lock)
{
	struct recent_iter_state *st = seq->private;
	const struct recent_table *t = st->table;
	struct recent_entry *e;
	loff_t p = *pos;

	spin_lock_bh(&recent_lock);

	for (st->bucket = 0; st->bucket < ip_list_hash_size; st->bucket++)
		list_for_each_entry(e, &t->iphash[st->bucket], list)
			if (p-- == 0)
				return e;
	return NULL;
}

Contributors
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CommitProp
Patrick McHardy
74
77.08%
2
50.00%
Stephen Frost
21
21.88%
1
25.00%
Jan Engelhardt
1
1.04%
1
25.00%
Total
96
100.00%
4
100.00%



static void *recent_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	struct recent_iter_state *st = seq->private;
	const struct recent_table *t = st->table;
	const struct recent_entry *e = v;
	const struct list_head *head = e->list.next;

	while (head == &t->iphash[st->bucket]) {
		if (++st->bucket >= ip_list_hash_size)
			return NULL;
		head = t->iphash[st->bucket].next;
	}
	(*pos)++;
	return list_entry(head, struct recent_entry, list);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Patrick McHardy
97
82.91%
1
25.00%
Stephen Frost
17
14.53%
1
25.00%
Jan Engelhardt
3
2.56%
2
50.00%
Total
117
100.00%
4
100.00%


static void recent_seq_stop(struct seq_file *s, void *v)
	__releases
(recent_lock)
{
	spin_unlock_bh(&recent_lock);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Patrick McHardy
19
76.00%
2
66.67%
Stephen Frost
6
24.00%
1
33.33%
Total
25
100.00%
3
100.00%



static int recent_seq_show(struct seq_file *seq, void *v)
{
	const struct recent_entry *e = v;
	struct recent_iter_state *st = seq->private;
	const struct recent_table *t = st->table;
	unsigned int i;

	i = (e->index - 1) & t->nstamps_max_mask;

	if (e->family == NFPROTO_IPV4)
		seq_printf(seq, "src=%pI4 ttl: %u last_seen: %lu oldest_pkt: %u",
			   &e->addr.ip, e->ttl, e->stamps[i], e->index);
	else
		seq_printf(seq, "src=%pI6 ttl: %u last_seen: %lu oldest_pkt: %u",
			   &e->addr.in6, e->ttl, e->stamps[i], e->index);
	for (i = 0; i < e->nstamps; i++)
		seq_printf(seq, "%s %lu", i ? "," : "", e->stamps[i]);
	seq_printf(seq, "\n");
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Patrick McHardy
87
50.58%
1
10.00%
Jan Engelhardt
39
22.67%
3
30.00%
Florian Westphal
23
13.37%
1
10.00%
Stephen Frost
18
10.47%
1
10.00%
Harvey Harrison
4
2.33%
3
30.00%
Rusty Russell
1
0.58%
1
10.00%
Total
172
100.00%
10
100.00%


static const struct seq_operations