From: Yasuyuki Kozakai Date: Sun, 8 Jul 2007 05:23:21 +0000 (-0700) Subject: [NETFILTER]: nf_conntrack: introduce extension infrastructure X-Git-Tag: v2.6.23-rc1~1109^2~82 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ecfab2c9fe5597221c2b30dec48634a2361a0d08;p=linux-2.6 [NETFILTER]: nf_conntrack: introduce extension infrastructure Old space allocator of conntrack had problems about extensibility. - It required slab cache per combination of extensions. - It expected what extensions would be assigned, but it was impossible to expect that completely, then we allocated bigger memory object than really required. - It needed to search helper twice due to lock issue. Now basic informations of a connection are stored in 'struct nf_conn'. And a storage for extension (helper, NAT) is allocated by kmalloc. Signed-off-by: Yasuyuki Kozakai Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h index 12a0e793cc..c31382d3ef 100644 --- a/include/net/netfilter/nf_conntrack.h +++ b/include/net/netfilter/nf_conntrack.h @@ -131,6 +131,9 @@ struct nf_conn /* Storage reserved for other modules: */ union nf_conntrack_proto proto; + /* Extensions */ + struct nf_ct_ext *ext; + /* features dynamically at the end: helper, nat (both optional) */ char data[0]; }; diff --git a/include/net/netfilter/nf_conntrack_extend.h b/include/net/netfilter/nf_conntrack_extend.h new file mode 100644 index 0000000000..8a988d1364 --- /dev/null +++ b/include/net/netfilter/nf_conntrack_extend.h @@ -0,0 +1,80 @@ +#ifndef _NF_CONNTRACK_EXTEND_H +#define _NF_CONNTRACK_EXTEND_H + +#include + +enum nf_ct_ext_id +{ + NF_CT_EXT_NUM, +}; + +/* Extensions: optional stuff which isn't permanently in struct. */ +struct nf_ct_ext { + u8 offset[NF_CT_EXT_NUM]; + u8 len; + u8 real_len; + char data[0]; +}; + +static inline int nf_ct_ext_exist(const struct nf_conn *ct, u8 id) +{ + return (ct->ext && ct->ext->offset[id]); +} + +static inline void *__nf_ct_ext_find(const struct nf_conn *ct, u8 id) +{ + if (!nf_ct_ext_exist(ct, id)) + return NULL; + + return (void *)ct->ext + ct->ext->offset[id]; +} +#define nf_ct_ext_find(ext, id) \ + ((id##_TYPE *)__nf_ct_ext_find((ext), (id))) + +/* Destroy all relationships */ +extern void __nf_ct_ext_destroy(struct nf_conn *ct); +static inline void nf_ct_ext_destroy(struct nf_conn *ct) +{ + if (ct->ext) + __nf_ct_ext_destroy(ct); +} + +/* Free operation. If you want to free a object referred from private area, + * please implement __nf_ct_ext_free() and call it. + */ +static inline void nf_ct_ext_free(struct nf_conn *ct) +{ + if (ct->ext) + kfree(ct->ext); +} + +/* Add this type, returns pointer to data or NULL. */ +void * +__nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp); +#define nf_ct_ext_add(ct, id, gfp) \ + ((id##_TYPE *)__nf_ct_ext_add((ct), (id), (gfp))) + +#define NF_CT_EXT_F_PREALLOC 0x0001 + +struct nf_ct_ext_type +{ + /* Destroys relationships (can be NULL). */ + void (*destroy)(struct nf_conn *ct); + /* Called when realloacted (can be NULL). + Contents has already been moved. */ + void (*move)(struct nf_conn *ct, void *old); + + enum nf_ct_ext_id id; + + unsigned int flags; + + /* Length and min alignment. */ + u8 len; + u8 align; + /* initial size of nf_ct_ext. */ + u8 alloc_size; +}; + +int nf_ct_extend_register(struct nf_ct_ext_type *type); +void nf_ct_extend_unregister(struct nf_ct_ext_type *type); +#endif /* _NF_CONNTRACK_EXTEND_H */ diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile index 3b792687f0..58b4245a17 100644 --- a/net/netfilter/Makefile +++ b/net/netfilter/Makefile @@ -1,6 +1,6 @@ netfilter-objs := core.o nf_log.o nf_queue.o nf_sockopt.o -nf_conntrack-y := nf_conntrack_core.o nf_conntrack_standalone.o nf_conntrack_expect.o nf_conntrack_helper.o nf_conntrack_proto.o nf_conntrack_l3proto_generic.o nf_conntrack_proto_generic.o nf_conntrack_proto_tcp.o nf_conntrack_proto_udp.o +nf_conntrack-y := nf_conntrack_core.o nf_conntrack_standalone.o nf_conntrack_expect.o nf_conntrack_helper.o nf_conntrack_proto.o nf_conntrack_l3proto_generic.o nf_conntrack_proto_generic.o nf_conntrack_proto_tcp.o nf_conntrack_proto_udp.o nf_conntrack_extend.o nf_conntrack-$(CONFIG_NF_CONNTRACK_EVENTS) += nf_conntrack_ecache.o obj-$(CONFIG_NETFILTER) = netfilter.o diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index 7a15e30356..b56f954895 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -36,6 +36,7 @@ #include #include #include +#include #define NF_CONNTRACK_VERSION "0.5.0" @@ -317,6 +318,8 @@ destroy_conntrack(struct nf_conntrack *nfct) if (l4proto && l4proto->destroy) l4proto->destroy(ct); + nf_ct_ext_destroy(ct); + destroyed = rcu_dereference(nf_conntrack_destroyed); if (destroyed) destroyed(ct); @@ -650,6 +653,7 @@ void nf_conntrack_free(struct nf_conn *conntrack) { u_int32_t features = conntrack->features; NF_CT_ASSERT(features >= NF_CT_F_BASIC && features < NF_CT_F_NUM); + nf_ct_ext_free(conntrack); DEBUGP("nf_conntrack_free: features = 0x%x, conntrack=%p\n", features, conntrack); kmem_cache_free(nf_ct_cache[features].cachep, conntrack); diff --git a/net/netfilter/nf_conntrack_extend.c b/net/netfilter/nf_conntrack_extend.c new file mode 100644 index 0000000000..a1a65a1313 --- /dev/null +++ b/net/netfilter/nf_conntrack_extend.c @@ -0,0 +1,195 @@ +/* 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 +#include +#include +#include +#include +#include +#include + +static struct nf_ct_ext_type *nf_ct_ext_types[NF_CT_EXT_NUM]; +static DEFINE_MUTEX(nf_ct_ext_type_mutex); + +/* Horrible trick to figure out smallest amount worth kmallocing. */ +#define CACHE(x) (x) + 0 * +enum { + NF_CT_EXT_MIN_SIZE = +#include + 1 }; +#undef CACHE + +void __nf_ct_ext_destroy(struct nf_conn *ct) +{ + unsigned int i; + struct nf_ct_ext_type *t; + + for (i = 0; i < NF_CT_EXT_NUM; i++) { + if (!nf_ct_ext_exist(ct, 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(); + } +} +EXPORT_SYMBOL(__nf_ct_ext_destroy); + +static void * +nf_ct_ext_create(struct nf_ct_ext **ext, enum nf_ct_ext_id id, gfp_t gfp) +{ + unsigned int off, len, real_len; + struct nf_ct_ext_type *t; + + 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; + real_len = t->alloc_size; + rcu_read_unlock(); + + *ext = kzalloc(real_len, gfp); + if (!*ext) + return NULL; + + (*ext)->offset[id] = off; + (*ext)->len = len; + (*ext)->real_len = real_len; + + return (void *)(*ext) + off; +} + +void *__nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp) +{ + struct nf_ct_ext *new; + int i, newlen, newoff; + struct nf_ct_ext_type *t; + + if (!ct->ext) + return nf_ct_ext_create(&ct->ext, id, gfp); + + if (nf_ct_ext_exist(ct, id)) + return NULL; + + rcu_read_lock(); + t = rcu_dereference(nf_ct_ext_types[id]); + BUG_ON(t == NULL); + + newoff = ALIGN(ct->ext->len, t->align); + newlen = newoff + t->len; + rcu_read_unlock(); + + if (newlen >= ct->ext->real_len) { + new = kmalloc(newlen, gfp); + if (!new) + return NULL; + + memcpy(new, ct->ext, ct->ext->len); + + for (i = 0; i < NF_CT_EXT_NUM; i++) { + if (!nf_ct_ext_exist(ct, i)) + continue; + + rcu_read_lock(); + t = rcu_dereference(nf_ct_ext_types[i]); + if (t && t->move) + t->move(ct, ct->ext + ct->ext->offset[id]); + rcu_read_unlock(); + } + kfree(ct->ext); + new->real_len = newlen; + ct->ext = new; + } + + ct->ext->offset[id] = newoff; + ct->ext->len = newlen; + memset((void *)ct->ext + newoff, 0, newlen - newoff); + return (void *)ct->ext + newoff; +} +EXPORT_SYMBOL(__nf_ct_ext_add); + +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 = nf_ct_ext_types[i]; + if (!t1) + continue; + + t1->alloc_size = sizeof(struct nf_ct_ext) + + ALIGN(sizeof(struct nf_ct_ext), t1->align) + + t1->len; + for (j = 0; j < NF_CT_EXT_NUM; j++) { + t2 = nf_ct_ext_types[j]; + 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; + } + if (t1->alloc_size < NF_CT_EXT_MIN_SIZE) + t1->alloc_size = NF_CT_EXT_MIN_SIZE; + } +} + +/* 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; +} +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_assign_pointer(nf_ct_ext_types[type->id], NULL); + update_alloc_size(type); + mutex_unlock(&nf_ct_ext_type_mutex); + synchronize_rcu(); +} +EXPORT_SYMBOL_GPL(nf_ct_extend_unregister);