cregit-Linux how code gets into the kernel

Release 4.8 net/netfilter/nf_conntrack_extend.c

Directory: net/netfilter
/* Structure dynamic extension infrastructure
 * Copyright (C) 2004 Rusty Russell IBM Corporation
 * Copyright (C) 2007 Netfilter Core Team <>
 * Copyright (C) 2007 USAGI/WIDE Project <>
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/rcupdate.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <net/netfilter/nf_conntrack_extend.h>

static struct nf_ct_ext_type __rcu *nf_ct_ext_types[NF_CT_EXT_NUM];
static DEFINE_MUTEX(nf_ct_ext_type_mutex);

void __nf_ct_ext_destroy(struct nf_conn *ct) { unsigned int i; struct nf_ct_ext_type *t; struct nf_ct_ext *ext = ct->ext; for (i = 0; i < NF_CT_EXT_NUM; i++) { if (!__nf_ct_ext_exist(ext, i)) continue; rcu_read_lock(); t = rcu_dereference(nf_ct_ext_types[i]); /* Here the nf_ct_ext_type might have been unregisterd. * I.e., it has responsible to cleanup private * area in all conntracks when it is unregisterd. */ if (t && t->destroy) t->destroy(ct); rcu_read_unlock(); } }


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static void * nf_ct_ext_create(struct nf_ct_ext **ext, enum nf_ct_ext_id id, size_t var_alloc_len, gfp_t gfp) { unsigned int off, len; struct nf_ct_ext_type *t; size_t alloc_size; rcu_read_lock(); t = rcu_dereference(nf_ct_ext_types[id]); BUG_ON(t == NULL); off = ALIGN(sizeof(struct nf_ct_ext), t->align); len = off + t->len + var_alloc_len; alloc_size = t->alloc_size + var_alloc_len; rcu_read_unlock(); *ext = kzalloc(alloc_size, gfp); if (!*ext) return NULL; (*ext)->offset[id] = off; (*ext)->len = len; return (void *)(*ext) + off; }


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eric dumazeteric dumazet96.21%125.00%
pablo neira ayusopablo neira ayuso74.83%125.00%
pekka j enbergpekka j enberg10.69%125.00%

void *__nf_ct_ext_add_length(struct nf_conn *ct, enum nf_ct_ext_id id, size_t var_alloc_len, gfp_t gfp) { struct nf_ct_ext *old, *new; int newlen, newoff; struct nf_ct_ext_type *t; /* Conntrack must not be confirmed to avoid races on reallocation. */ NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); old = ct->ext; if (!old) return nf_ct_ext_create(&ct->ext, id, var_alloc_len, gfp); if (__nf_ct_ext_exist(old, id)) return NULL; rcu_read_lock(); t = rcu_dereference(nf_ct_ext_types[id]); BUG_ON(t == NULL); newoff = ALIGN(old->len, t->align); newlen = newoff + t->len + var_alloc_len; rcu_read_unlock(); new = __krealloc(old, newlen, gfp); if (!new) return NULL; if (new != old) { kfree_rcu(old, rcu); rcu_assign_pointer(ct->ext, new); } new->offset[id] = newoff; new->len = newlen; memset((void *)new + newoff, 0, newlen - newoff); return (void *)new + newoff; }


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changli gaochangli gao167.37%19.09%
patrick mchardypatrick mchardy156.91%327.27%
pekka j enbergpekka j enberg104.61%327.27%
pablo neira ayusopablo neira ayuso83.69%19.09%
florian westphalflorian westphal41.84%19.09%
lai jiangshanlai jiangshan20.92%19.09%

static void update_alloc_size(struct nf_ct_ext_type *type) { int i, j; struct nf_ct_ext_type *t1, *t2; enum nf_ct_ext_id min = 0, max = NF_CT_EXT_NUM - 1; /* unnecessary to update all types */ if ((type->flags & NF_CT_EXT_F_PREALLOC) == 0) { min = type->id; max = type->id; } /* This assumes that extended areas in conntrack for the types whose NF_CT_EXT_F_PREALLOC bit set are allocated in order */ for (i = min; i <= max; i++) { t1 = rcu_dereference_protected(nf_ct_ext_types[i], lockdep_is_held(&nf_ct_ext_type_mutex)); if (!t1) continue; t1->alloc_size = ALIGN(sizeof(struct nf_ct_ext), t1->align) + t1->len; for (j = 0; j < NF_CT_EXT_NUM; j++) { t2 = rcu_dereference_protected(nf_ct_ext_types[j], lockdep_is_held(&nf_ct_ext_type_mutex)); if (t2 == NULL || t2 == t1 || (t2->flags & NF_CT_EXT_F_PREALLOC) == 0) continue; t1->alloc_size = ALIGN(t1->alloc_size, t2->align) + t2->len; } } }


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eric dumazeteric dumazet189.33%150.00%

/* This MUST be called in process context. */
int nf_ct_extend_register(struct nf_ct_ext_type *type) { int ret = 0; mutex_lock(&nf_ct_ext_type_mutex); if (nf_ct_ext_types[type->id]) { ret = -EBUSY; goto out; } /* This ensures that nf_ct_ext_create() can allocate enough area before updating alloc_size */ type->alloc_size = ALIGN(sizeof(struct nf_ct_ext), type->align) + type->len; rcu_assign_pointer(nf_ct_ext_types[type->id], type); update_alloc_size(type); out: mutex_unlock(&nf_ct_ext_type_mutex); return ret; }


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eric dumazeteric dumazet11.11%150.00%

EXPORT_SYMBOL_GPL(nf_ct_extend_register); /* This MUST be called in process context. */
void nf_ct_extend_unregister(struct nf_ct_ext_type *type) { mutex_lock(&nf_ct_ext_type_mutex); RCU_INIT_POINTER(nf_ct_ext_types[type->id], NULL); update_alloc_size(type); mutex_unlock(&nf_ct_ext_type_mutex); rcu_barrier(); /* Wait for completion of call_rcu()'s */ }


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jesper dangaard brouerjesper dangaard brouer24.65%133.33%
stephen hemmingerstephen hemminger12.33%133.33%


Overall Contributors

yasuyuki kozakaiyasuyuki kozakai72787.17%15.88%
eric dumazeteric dumazet283.36%317.65%
changli gaochangli gao273.24%15.88%
pablo neira ayusopablo neira ayuso161.92%15.88%
patrick mchardypatrick mchardy151.80%317.65%
pekka j enbergpekka j enberg111.32%317.65%
florian westphalflorian westphal40.48%15.88%
lai jiangshanlai jiangshan20.24%15.88%
jesper dangaard brouerjesper dangaard brouer20.24%15.88%
arnd bergmannarnd bergmann10.12%15.88%
stephen hemmingerstephen hemminger10.12%15.88%
Directory: net/netfilter
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