net/netfilter/nf_conntrack_extend.c

   1 /* Structure dynamic extension infrastructure
   2  * Copyright (C) 2004 Rusty Russell IBM Corporation
   3  * Copyright (C) 2007 Netfilter Core Team <coreteam@netfilter.org>
   4  * Copyright (C) 2007 USAGI/WIDE Project <http://www.linux-ipv6.org>
   5  *
   6  *      This program is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU General Public License
   8  *      as published by the Free Software Foundation; either version
   9  *      2 of the License, or (at your option) any later version.
  10  */
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/mutex.h>
  14 #include <linux/rcupdate.h>
  15 #include <linux/slab.h>
  16 #include <linux/skbuff.h>
  17 #include <net/netfilter/nf_conntrack_extend.h>
  18
  19 static struct nf_ct_ext_type *nf_ct_ext_types[NF_CT_EXT_NUM];
  20 static DEFINE_MUTEX(nf_ct_ext_type_mutex);
  21
  22 <<<<<<< HEAD:net/netfilter/nf_conntrack_extend.c
  23 /* Horrible trick to figure out smallest amount worth kmallocing. */
  24 #define CACHE(x) (x) + 0 *
  25 enum {
  26         NF_CT_EXT_MIN_SIZE =
  27 #include <linux/kmalloc_sizes.h>
  28         1 };
  29 #undef CACHE
  30
  31 =======
  32 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:net/netfilter/nf_conntrack_extend.c
  33 void __nf_ct_ext_destroy(struct nf_conn *ct)
  34 {
  35         unsigned int i;
  36         struct nf_ct_ext_type *t;
  37
  38         for (i = 0; i < NF_CT_EXT_NUM; i++) {
  39                 if (!nf_ct_ext_exist(ct, i))
  40                         continue;
  41
  42                 rcu_read_lock();
  43                 t = rcu_dereference(nf_ct_ext_types[i]);
  44
  45                 /* Here the nf_ct_ext_type might have been unregisterd.
  46                  * I.e., it has responsible to cleanup private
  47                  * area in all conntracks when it is unregisterd.
  48                  */
  49                 if (t && t->destroy)
  50                         t->destroy(ct);
  51                 rcu_read_unlock();
  52         }
  53 }
  54 EXPORT_SYMBOL(__nf_ct_ext_destroy);
  55
  56 static void *
  57 nf_ct_ext_create(struct nf_ct_ext **ext, enum nf_ct_ext_id id, gfp_t gfp)
  58 {
  59 <<<<<<< HEAD:net/netfilter/nf_conntrack_extend.c
  60         unsigned int off, len, real_len;
  61 =======
  62         unsigned int off, len;
  63 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:net/netfilter/nf_conntrack_extend.c
  64         struct nf_ct_ext_type *t;
  65
  66         rcu_read_lock();
  67         t = rcu_dereference(nf_ct_ext_types[id]);
  68         BUG_ON(t == NULL);
  69         off = ALIGN(sizeof(struct nf_ct_ext), t->align);
  70         len = off + t->len;
  71 <<<<<<< HEAD:net/netfilter/nf_conntrack_extend.c
  72         real_len = t->alloc_size;
  73 =======
  74 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:net/netfilter/nf_conntrack_extend.c
  75         rcu_read_unlock();
  76
  77 <<<<<<< HEAD:net/netfilter/nf_conntrack_extend.c
  78         *ext = kzalloc(real_len, gfp);
  79 =======
  80         *ext = kzalloc(t->alloc_size, gfp);
  81 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:net/netfilter/nf_conntrack_extend.c
  82         if (!*ext)
  83                 return NULL;
  84
  85         (*ext)->offset[id] = off;
  86         (*ext)->len = len;
  87 <<<<<<< HEAD:net/netfilter/nf_conntrack_extend.c
  88         (*ext)->real_len = real_len;
  89 =======
  90 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:net/netfilter/nf_conntrack_extend.c
  91
  92         return (void *)(*ext) + off;
  93 }
  94
  95 void *__nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp)
  96 {
  97         struct nf_ct_ext *new;
  98         int i, newlen, newoff;
  99         struct nf_ct_ext_type *t;
 100
 101         if (!ct->ext)
 102                 return nf_ct_ext_create(&ct->ext, id, gfp);
 103
 104         if (nf_ct_ext_exist(ct, id))
 105                 return NULL;
 106
 107         rcu_read_lock();
 108         t = rcu_dereference(nf_ct_ext_types[id]);
 109         BUG_ON(t == NULL);
 110
 111         newoff = ALIGN(ct->ext->len, t->align);
 112         newlen = newoff + t->len;
 113         rcu_read_unlock();
 114
 115 <<<<<<< HEAD:net/netfilter/nf_conntrack_extend.c
 116         if (newlen >= ct->ext->real_len) {
 117 =======
 118         if (newlen >= ksize(ct->ext)) {
 119 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:net/netfilter/nf_conntrack_extend.c
 120                 new = kmalloc(newlen, gfp);
 121                 if (!new)
 122                         return NULL;
 123
 124                 memcpy(new, ct->ext, ct->ext->len);
 125
 126                 for (i = 0; i < NF_CT_EXT_NUM; i++) {
 127                         if (!nf_ct_ext_exist(ct, i))
 128                                 continue;
 129
 130                         rcu_read_lock();
 131                         t = rcu_dereference(nf_ct_ext_types[i]);
 132                         if (t && t->move)
 133                                 t->move((void *)new + new->offset[i],
 134                                         (void *)ct->ext + ct->ext->offset[i]);
 135                         rcu_read_unlock();
 136                 }
 137                 kfree(ct->ext);
 138 <<<<<<< HEAD:net/netfilter/nf_conntrack_extend.c
 139                 new->real_len = newlen;
 140 =======
 141 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:net/netfilter/nf_conntrack_extend.c
 142                 ct->ext = new;
 143         }
 144
 145         ct->ext->offset[id] = newoff;
 146         ct->ext->len = newlen;
 147         memset((void *)ct->ext + newoff, 0, newlen - newoff);
 148         return (void *)ct->ext + newoff;
 149 }
 150 EXPORT_SYMBOL(__nf_ct_ext_add);
 151
 152 static void update_alloc_size(struct nf_ct_ext_type *type)
 153 {
 154         int i, j;
 155         struct nf_ct_ext_type *t1, *t2;
 156         enum nf_ct_ext_id min = 0, max = NF_CT_EXT_NUM - 1;
 157
 158         /* unnecessary to update all types */
 159         if ((type->flags & NF_CT_EXT_F_PREALLOC) == 0) {
 160                 min = type->id;
 161                 max = type->id;
 162         }
 163
 164         /* This assumes that extended areas in conntrack for the types
 165            whose NF_CT_EXT_F_PREALLOC bit set are allocated in order */
 166         for (i = min; i <= max; i++) {
 167                 t1 = nf_ct_ext_types[i];
 168                 if (!t1)
 169                         continue;
 170
 171                 t1->alloc_size = sizeof(struct nf_ct_ext)
 172                                  + ALIGN(sizeof(struct nf_ct_ext), t1->align)
 173                                  + t1->len;
 174                 for (j = 0; j < NF_CT_EXT_NUM; j++) {
 175                         t2 = nf_ct_ext_types[j];
 176                         if (t2 == NULL || t2 == t1 ||
 177                             (t2->flags & NF_CT_EXT_F_PREALLOC) == 0)
 178                                 continue;
 179
 180                         t1->alloc_size = ALIGN(t1->alloc_size, t2->align)
 181                                          + t2->len;
 182                 }
 183 <<<<<<< HEAD:net/netfilter/nf_conntrack_extend.c
 184                 if (t1->alloc_size < NF_CT_EXT_MIN_SIZE)
 185                         t1->alloc_size = NF_CT_EXT_MIN_SIZE;
 186 =======
 187 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:net/netfilter/nf_conntrack_extend.c
 188         }
 189 }
 190
 191 /* This MUST be called in process context. */
 192 int nf_ct_extend_register(struct nf_ct_ext_type *type)
 193 {
 194         int ret = 0;
 195
 196         mutex_lock(&nf_ct_ext_type_mutex);
 197         if (nf_ct_ext_types[type->id]) {
 198                 ret = -EBUSY;
 199                 goto out;
 200         }
 201
 202         /* This ensures that nf_ct_ext_create() can allocate enough area
 203            before updating alloc_size */
 204         type->alloc_size = ALIGN(sizeof(struct nf_ct_ext), type->align)
 205                            + type->len;
 206         rcu_assign_pointer(nf_ct_ext_types[type->id], type);
 207         update_alloc_size(type);
 208 out:
 209         mutex_unlock(&nf_ct_ext_type_mutex);
 210         return ret;
 211 }
 212 EXPORT_SYMBOL_GPL(nf_ct_extend_register);
 213
 214 /* This MUST be called in process context. */
 215 void nf_ct_extend_unregister(struct nf_ct_ext_type *type)
 216 {
 217         mutex_lock(&nf_ct_ext_type_mutex);
 218         rcu_assign_pointer(nf_ct_ext_types[type->id], NULL);
 219         update_alloc_size(type);
 220         mutex_unlock(&nf_ct_ext_type_mutex);
 221         synchronize_rcu();
 222 }
 223 EXPORT_SYMBOL_GPL(nf_ct_extend_unregister);