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Release 4.8 net/netfilter/nf_conntrack_expect.c

Directory: net/netfilter
/* Expectation handling for nf_conntrack. */

/* (C) 1999-2001 Paul `Rusty' Russell
 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
 * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
 * (c) 2005-2012 Patrick McHardy <kaber@trash.net>
 *
 * 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.
 */

#include <linux/types.h>
#include <linux/netfilter.h>
#include <linux/skbuff.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/stddef.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/percpu.h>
#include <linux/kernel.h>
#include <linux/jhash.h>
#include <linux/moduleparam.h>
#include <linux/export.h>
#include <net/net_namespace.h>
#include <net/netns/hash.h>

#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/nf_conntrack_expect.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_tuple.h>
#include <net/netfilter/nf_conntrack_zones.h>


unsigned int nf_ct_expect_hsize __read_mostly;

EXPORT_SYMBOL_GPL(nf_ct_expect_hsize);


struct hlist_head *nf_ct_expect_hash __read_mostly;

EXPORT_SYMBOL_GPL(nf_ct_expect_hash);


unsigned int nf_ct_expect_max __read_mostly;


static struct kmem_cache *nf_ct_expect_cachep __read_mostly;

static unsigned int nf_ct_expect_hashrnd __read_mostly;

/* nf_conntrack_expect helper functions */

void nf_ct_unlink_expect_report(struct nf_conntrack_expect *exp, u32 portid, int report) { struct nf_conn_help *master_help = nfct_help(exp->master); struct net *net = nf_ct_exp_net(exp); NF_CT_ASSERT(master_help); NF_CT_ASSERT(!timer_pending(&exp->timeout)); hlist_del_rcu(&exp->hnode); net->ct.expect_count--; hlist_del(&exp->lnode); master_help->expecting[exp->class]--; nf_ct_expect_event_report(IPEXP_DESTROY, exp, portid, report); nf_ct_expect_put(exp); NF_CT_STAT_INC(net, expect_delete); }

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martin josefssonmartin josefsson4540.54%19.09%
patrick mchardypatrick mchardy2825.23%654.55%
pablo neira ayusopablo neira ayuso2118.92%218.18%
alexey dobriyanalexey dobriyan1715.32%218.18%
Total111100.00%11100.00%

EXPORT_SYMBOL_GPL(nf_ct_unlink_expect_report);
static void nf_ct_expectation_timed_out(unsigned long ul_expect) { struct nf_conntrack_expect *exp = (void *)ul_expect; spin_lock_bh(&nf_conntrack_expect_lock); nf_ct_unlink_expect(exp); spin_unlock_bh(&nf_conntrack_expect_lock); nf_ct_expect_put(exp); }

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martin josefssonmartin josefsson3786.05%125.00%
patrick mchardypatrick mchardy49.30%250.00%
jesper dangaard brouerjesper dangaard brouer24.65%125.00%
Total43100.00%4100.00%


static unsigned int nf_ct_expect_dst_hash(const struct net *n, const struct nf_conntrack_tuple *tuple) { unsigned int hash, seed; get_random_once(&nf_ct_expect_hashrnd, sizeof(nf_ct_expect_hashrnd)); seed = nf_ct_expect_hashrnd ^ net_hash_mix(n); hash = jhash2(tuple->dst.u3.all, ARRAY_SIZE(tuple->dst.u3.all), (((tuple->dst.protonum ^ tuple->src.l3num) << 16) | (__force __u16)tuple->dst.u.all) ^ seed); return reciprocal_scale(hash, nf_ct_expect_hsize); }

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patrick mchardypatrick mchardy7769.37%233.33%
florian westphalflorian westphal2623.42%233.33%
daniel borkmanndaniel borkmann43.60%116.67%
al viroal viro43.60%116.67%
Total111100.00%6100.00%


static bool nf_ct_exp_equal(const struct nf_conntrack_tuple *tuple, const struct nf_conntrack_expect *i, const struct nf_conntrack_zone *zone, const struct net *net) { return nf_ct_tuple_mask_cmp(tuple, &i->tuple, &i->mask) && net_eq(net, nf_ct_net(i->master)) && nf_ct_zone_equal_any(i->master, zone); }

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florian westphalflorian westphal67100.00%1100.00%
Total67100.00%1100.00%


struct nf_conntrack_expect * __nf_ct_expect_find(struct net *net, const struct nf_conntrack_zone *zone, const struct nf_conntrack_tuple *tuple) { struct nf_conntrack_expect *i; unsigned int h; if (!net->ct.expect_count) return NULL; h = nf_ct_expect_dst_hash(net, tuple); hlist_for_each_entry_rcu(i, &nf_ct_expect_hash[h], hnode) { if (nf_ct_exp_equal(tuple, i, zone, net)) return i; } return NULL; }

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martin josefssonmartin josefsson3542.17%110.00%
patrick mchardypatrick mchardy2631.33%440.00%
alexey dobriyanalexey dobriyan1012.05%110.00%
daniel borkmanndaniel borkmann67.23%110.00%
florian westphalflorian westphal67.23%330.00%
Total83100.00%10100.00%

EXPORT_SYMBOL_GPL(__nf_ct_expect_find); /* Just find a expectation corresponding to a tuple. */
struct nf_conntrack_expect * nf_ct_expect_find_get(struct net *net, const struct nf_conntrack_zone *zone, const struct nf_conntrack_tuple *tuple) { struct nf_conntrack_expect *i; rcu_read_lock(); i = __nf_ct_expect_find(net, zone, tuple); if (i && !atomic_inc_not_zero(&i->use)) i = NULL; rcu_read_unlock(); return i; }

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martin josefssonmartin josefsson3857.58%116.67%
patrick mchardypatrick mchardy1725.76%350.00%
alexey dobriyanalexey dobriyan710.61%116.67%
daniel borkmanndaniel borkmann46.06%116.67%
Total66100.00%6100.00%

EXPORT_SYMBOL_GPL(nf_ct_expect_find_get); /* If an expectation for this connection is found, it gets delete from * global list then returned. */
struct nf_conntrack_expect * nf_ct_find_expectation(struct net *net, const struct nf_conntrack_zone *zone, const struct nf_conntrack_tuple *tuple) { struct nf_conntrack_expect *i, *exp = NULL; unsigned int h; if (!net->ct.expect_count) return NULL; h = nf_ct_expect_dst_hash(net, tuple); hlist_for_each_entry(i, &nf_ct_expect_hash[h], hnode) { if (!(i->flags & NF_CT_EXPECT_INACTIVE) && nf_ct_exp_equal(tuple, i, zone, net)) { exp = i; break; } } if (!exp) return NULL; /* If master is not in hash table yet (ie. packet hasn't left this machine yet), how can other end know about expected? Hence these are not the droids you are looking for (if master ct never got confirmed, we'd hold a reference to it and weird things would happen to future packets). */ if (!nf_ct_is_confirmed(exp->master)) return NULL; /* Avoid race with other CPUs, that for exp->master ct, is * about to invoke ->destroy(), or nf_ct_delete() via timeout * or early_drop(). * * The atomic_inc_not_zero() check tells: If that fails, we * know that the ct is being destroyed. If it succeeds, we * can be sure the ct cannot disappear underneath. */ if (unlikely(nf_ct_is_dying(exp->master) || !atomic_inc_not_zero(&exp->master->ct_general.use))) return NULL; if (exp->flags & NF_CT_EXPECT_PERMANENT) { atomic_inc(&exp->use); return exp; } else if (del_timer(&exp->timeout)) { nf_ct_unlink_expect(exp); return exp; } /* Undo exp->master refcnt increase, if del_timer() failed */ nf_ct_put(exp->master); return NULL; }

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martin josefssonmartin josefsson6532.18%19.09%
patrick mchardypatrick mchardy5527.23%327.27%
jesper dangaard brouerjesper dangaard brouer3718.32%19.09%
yasuyuki kozakaiyasuyuki kozakai2311.39%19.09%
alexey dobriyanalexey dobriyan104.95%19.09%
daniel borkmanndaniel borkmann62.97%19.09%
florian westphalflorian westphal62.97%327.27%
Total202100.00%11100.00%

/* delete all expectations for this conntrack */
void nf_ct_remove_expectations(struct nf_conn *ct) { struct nf_conn_help *help = nfct_help(ct); struct nf_conntrack_expect *exp; struct hlist_node *next; /* Optimization: most connection never expect any others. */ if (!help) return; spin_lock_bh(&nf_conntrack_expect_lock); hlist_for_each_entry_safe(exp, next, &help->expectations, lnode) { if (del_timer(&exp->timeout)) { nf_ct_unlink_expect(exp); nf_ct_expect_put(exp); } } spin_unlock_bh(&nf_conntrack_expect_lock); }

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martin josefssonmartin josefsson5161.45%125.00%
patrick mchardypatrick mchardy2024.10%250.00%
jesper dangaard brouerjesper dangaard brouer1214.46%125.00%
Total83100.00%4100.00%

EXPORT_SYMBOL_GPL(nf_ct_remove_expectations); /* Would two expected things clash? */
static inline int expect_clash(const struct nf_conntrack_expect *a, const struct nf_conntrack_expect *b) { /* Part covered by intersection of masks must be unequal, otherwise they clash */ struct nf_conntrack_tuple_mask intersect_mask; int count; intersect_mask.src.u.all = a->mask.src.u.all & b->mask.src.u.all; for (count = 0; count < NF_CT_TUPLE_L3SIZE; count++){ intersect_mask.src.u3.all[count] = a->mask.src.u3.all[count] & b->mask.src.u3.all[count]; } return nf_ct_tuple_mask_cmp(&a->tuple, &b->tuple, &intersect_mask) && net_eq(nf_ct_net(a->master), nf_ct_net(b->master)) && nf_ct_zone_equal_any(a->master, nf_ct_zone(b->master)); }

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martin josefssonmartin josefsson12379.35%116.67%
florian westphalflorian westphal1710.97%116.67%
joe stringerjoe stringer117.10%116.67%
daniel borkmanndaniel borkmann31.94%233.33%
patrick mchardypatrick mchardy10.65%116.67%
Total155100.00%6100.00%


static inline int expect_matches(const struct nf_conntrack_expect *a, const struct nf_conntrack_expect *b) { return a->master == b->master && a->class == b->class && nf_ct_tuple_equal(&a->tuple, &b->tuple) && nf_ct_tuple_mask_equal(&a->mask, &b->mask) && net_eq(nf_ct_net(a->master), nf_ct_net(b->master)) && nf_ct_zone_equal_any(a->master, nf_ct_zone(b->master)); }

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martin josefssonmartin josefsson5356.99%114.29%
patrick mchardypatrick mchardy2021.51%342.86%
florian westphalflorian westphal1718.28%114.29%
daniel borkmanndaniel borkmann33.23%228.57%
Total93100.00%7100.00%

/* Generally a bad idea to call this: could have matched already. */
void nf_ct_unexpect_related(struct nf_conntrack_expect *exp) { spin_lock_bh(&nf_conntrack_expect_lock); if (del_timer(&exp->timeout)) { nf_ct_unlink_expect(exp); nf_ct_expect_put(exp); } spin_unlock_bh(&nf_conntrack_expect_lock); }

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martin josefssonmartin josefsson3579.55%120.00%
patrick mchardypatrick mchardy715.91%360.00%
jesper dangaard brouerjesper dangaard brouer24.55%120.00%
Total44100.00%5100.00%

EXPORT_SYMBOL_GPL(nf_ct_unexpect_related); /* We don't increase the master conntrack refcount for non-fulfilled * conntracks. During the conntrack destruction, the expectations are * always killed before the conntrack itself */
struct nf_conntrack_expect *nf_ct_expect_alloc(struct nf_conn *me) { struct nf_conntrack_expect *new; new = kmem_cache_alloc(nf_ct_expect_cachep, GFP_ATOMIC); if (!new) return NULL; new->master = me; atomic_set(&new->use, 1); return new; }

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martin josefssonmartin josefsson5196.23%150.00%
patrick mchardypatrick mchardy23.77%150.00%
Total53100.00%2100.00%

EXPORT_SYMBOL_GPL(nf_ct_expect_alloc);
void nf_ct_expect_init(struct nf_conntrack_expect *exp, unsigned int class, u_int8_t family, const union nf_inet_addr *saddr, const union nf_inet_addr *daddr, u_int8_t proto, const __be16 *src, const __be16 *dst) { int len; if (family == AF_INET) len = 4; else len = 16; exp->flags = 0; exp->class = class; exp->expectfn = NULL; exp->helper = NULL; exp->tuple.src.l3num = family; exp->tuple.dst.protonum = proto; if (saddr) { memcpy(&exp->tuple.src.u3, saddr, len); if (sizeof(exp->tuple.src.u3) > len) /* address needs to be cleared for nf_ct_tuple_equal */ memset((void *)&exp->tuple.src.u3 + len, 0x00, sizeof(exp->tuple.src.u3) - len); memset(&exp->mask.src.u3, 0xFF, len); if (sizeof(exp->mask.src.u3) > len) memset((void *)&exp->mask.src.u3 + len, 0x00, sizeof(exp->mask.src.u3) - len); } else { memset(&exp->tuple.src.u3, 0x00, sizeof(exp->tuple.src.u3)); memset(&exp->mask.src.u3, 0x00, sizeof(exp->mask.src.u3)); } if (src) { exp->tuple.src.u.all = *src; exp->mask.src.u.all = htons(0xFFFF); } else { exp->tuple.src.u.all = 0; exp->mask.src.u.all = 0; } memcpy(&exp->tuple.dst.u3, daddr, len); if (sizeof(exp->tuple.dst.u3) > len) /* address needs to be cleared for nf_ct_tuple_equal */ memset((void *)&exp->tuple.dst.u3 + len, 0x00, sizeof(exp->tuple.dst.u3) - len); exp->tuple.dst.u.all = *dst; #ifdef CONFIG_NF_NAT_NEEDED memset(&exp->saved_addr, 0, sizeof(exp->saved_addr)); memset(&exp->saved_proto, 0, sizeof(exp->saved_proto)); #endif }

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patrick mchardypatrick mchardy42590.43%555.56%
pablo neira ayusopablo neira ayuso398.30%111.11%
al viroal viro30.64%111.11%
jan engelhardtjan engelhardt30.64%222.22%
Total470100.00%9100.00%

EXPORT_SYMBOL_GPL(nf_ct_expect_init);
static void nf_ct_expect_free_rcu(struct rcu_head *head) { struct nf_conntrack_expect *exp; exp = container_of(head, struct nf_conntrack_expect, rcu); kmem_cache_free(nf_ct_expect_cachep, exp); }

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patrick mchardypatrick mchardy35100.00%1100.00%
Total35100.00%1100.00%


void nf_ct_expect_put(struct nf_conntrack_expect *exp) { if (atomic_dec_and_test(&exp->use)) call_rcu(&exp->rcu, nf_ct_expect_free_rcu); }

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martin josefssonmartin josefsson2376.67%133.33%
patrick mchardypatrick mchardy723.33%266.67%
Total30100.00%3100.00%

EXPORT_SYMBOL_GPL(nf_ct_expect_put);
static int nf_ct_expect_insert(struct nf_conntrack_expect *exp) { struct nf_conn_help *master_help = nfct_help(exp->master); struct nf_conntrack_helper *helper; struct net *net = nf_ct_exp_net(exp); unsigned int h = nf_ct_expect_dst_hash(net, &exp->tuple); /* two references : one for hash insert, one for the timer */ atomic_add(2, &exp->use); hlist_add_head(&exp->lnode, &master_help->expectations); master_help->expecting[exp->class]++; hlist_add_head_rcu(&exp->hnode, &nf_ct_expect_hash[h]); net->ct.expect_count++; setup_timer(&exp->timeout, nf_ct_expectation_timed_out, (unsigned long)exp); helper = rcu_dereference_protected(master_help->helper, lockdep_is_held(&nf_conntrack_expect_lock)); if (helper) { exp->timeout.expires = jiffies + helper->expect_policy[exp->class].timeout * HZ; } add_timer(&exp->timeout); NF_CT_STAT_INC(net, expect_create); return 0; }

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martin josefssonmartin josefsson7339.89%16.25%
patrick mchardypatrick mchardy5328.96%637.50%
pablo neira ayusopablo neira ayuso2413.11%212.50%
alexey dobriyanalexey dobriyan179.29%212.50%
eric dumazeteric dumazet126.56%212.50%
florian westphalflorian westphal31.64%212.50%
jesper dangaard brouerjesper dangaard brouer10.55%16.25%
Total183100.00%16100.00%

/* Race with expectations being used means we could have none to find; OK. */
static void evict_oldest_expect(struct nf_conn *master, struct nf_conntrack_expect *new) { struct nf_conn_help *master_help = nfct_help(master); struct nf_conntrack_expect *exp, *last = NULL; hlist_for_each_entry(exp, &master_help->expectations, lnode) { if (exp->class == new->class) last = exp; } if (last && del_timer(&last->timeout)) { nf_ct_unlink_expect(last); nf_ct_expect_put(last); } }

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patrick mchardypatrick mchardy4958.33%375.00%
martin josefssonmartin josefsson3541.67%125.00%
Total84100.00%4100.00%


static inline int __nf_ct_expect_check(struct nf_conntrack_expect *expect) { const struct nf_conntrack_expect_policy *p; struct nf_conntrack_expect *i; struct nf_conn *master = expect->master; struct nf_conn_help *master_help = nfct_help(master); struct nf_conntrack_helper *helper; struct net *net = nf_ct_exp_net(expect); struct hlist_node *next; unsigned int h; int ret = 1; if (!master_help) { ret = -ESHUTDOWN; goto out; } h = nf_ct_expect_dst_hash(net, &expect->tuple); hlist_for_each_entry_safe(i, next, &nf_ct_expect_hash[h], hnode) { if (expect_matches(i, expect)) { if (del_timer(&i->timeout)) { nf_ct_unlink_expect(i); nf_ct_expect_put(i); break; } } else if (expect_clash(i, expect)) { ret = -EBUSY; goto out; } } /* Will be over limit? */ helper = rcu_dereference_protected(master_help->helper, lockdep_is_held(&nf_conntrack_expect_lock)); if (helper) { p = &helper->expect_policy[expect->class]; if (p->max_expected && master_help->expecting[expect->class] >= p->max_expected) { evict_oldest_expect(master, expect); if (master_help->expecting[expect->class] >= p->max_expected) { ret = -EMFILE; goto out; } } } if (net->ct.expect_count >= nf_ct_expect_max) { net_warn_ratelimited("nf_conntrack: expectation table full\n"); ret = -EMFILE; } out: return ret; }

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patrick mchardypatrick mchardy10136.33%423.53%
martin josefssonmartin josefsson10035.97%15.88%
pablo neira ayusopablo neira ayuso4817.27%529.41%
alexey dobriyanalexey dobriyan165.76%211.76%
eric dumazeteric dumazet82.88%15.88%
florian westphalflorian westphal31.08%211.76%
joe perchesjoe perches10.36%15.88%
jesper dangaard brouerjesper dangaard brouer10.36%15.88%
Total278100.00%17100.00%


int nf_ct_expect_related_report(struct nf_conntrack_expect *expect, u32 portid, int report) { int ret; spin_lock_bh(&nf_conntrack_expect_lock); ret = __nf_ct_expect_check(expect); if (ret <= 0) goto out; ret = nf_ct_expect_insert(expect); if (ret < 0) goto out; spin_unlock_bh(&nf_conntrack_expect_lock); nf_ct_expect_event_report(IPEXP_NEW, expect, portid, report); return ret; out: spin_unlock_bh(&nf_conntrack_expect_lock); return ret; }

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pablo neira ayusopablo neira ayuso7079.55%342.86%
martin josefssonmartin josefsson1213.64%114.29%
patrick mchardypatrick mchardy33.41%228.57%
jesper dangaard brouerjesper dangaard brouer33.41%114.29%
Total88100.00%7100.00%

EXPORT_SYMBOL_GPL(nf_ct_expect_related_report); #ifdef CONFIG_NF_CONNTRACK_PROCFS struct ct_expect_iter_state { struct seq_net_private p; unsigned int bucket; };
static struct hlist_node *ct_expect_get_first(struct seq_file *seq) { struct ct_expect_iter_state *st = seq->private; struct hlist_node *n; for (st->bucket = 0; st->bucket < nf_ct_expect_hsize; st->bucket++) { n = rcu_dereference(hlist_first_rcu(&nf_ct_expect_hash[st->bucket])); if (n) return n; } return NULL; }

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patrick mchardypatrick mchardy4864.86%240.00%
martin josefssonmartin josefsson2128.38%120.00%
eric dumazeteric dumazet45.41%120.00%
florian westphalflorian westphal11.35%120.00%
Total74100.00%5100.00%


static struct hlist_node *ct_expect_get_next(struct seq_file *seq, struct hlist_node *head) { struct ct_expect_iter_state *st = seq->private; head = rcu_dereference(hlist_next_rcu(head)); while (head == NULL) { if (++st->bucket >= nf_ct_expect_hsize) return NULL; head = rcu_dereference(hlist_first_rcu(&nf_ct_expect_hash[st->bucket])); } return head; }

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patrick mchardypatrick mchardy5876.32%240.00%
martin josefssonmartin josefsson1013.16%120.00%
eric dumazeteric dumazet79.21%120.00%
florian westphalflorian westphal11.32%120.00%
Total76100.00%5100.00%


static struct hlist_node *ct_expect_get_idx(struct seq_file *seq, loff_t pos) { struct hlist_node *head = ct_expect_get_first(seq); if (head) while (pos && (head = ct_expect_get_next(seq, head))) pos--; return pos ? NULL : head; }

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patrick mchardypatrick mchardy55100.00%1100.00%
Total55100.00%1100.00%


static void *exp_seq_start(struct seq_file *seq, loff_t *pos) __acquires (RCU) { rcu_read_lock(); return ct_expect_get_idx(seq, *pos); }

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patrick mchardypatrick mchardy2784.38%250.00%
eric dumazeteric dumazet39.38%125.00%
martin josefssonmartin josefsson26.25%125.00%
Total32100.00%4100.00%


static void *exp_seq_next(struct seq_file *seq, void *v, loff_t *pos) { (*pos)++; return ct_expect_get_next(seq, v); }

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martin josefssonmartin josefsson2470.59%150.00%
patrick mchardypatrick mchardy1029.41%150.00%
Total34100.00%2100.00%


static void exp_seq_stop(struct seq_file *seq, void *