From: Florian Westphal <fw@xxxxxxxxx>
After this change conntrack operations (lookup, creation, matching from
ruleset) only access one instead of two sk_buff cache lines.
This works for normal conntracks because those are allocated from a slab
that guarantees hw cacheline or 8byte alignment (whatever is larger)
so the 3 bits needed for ctinfo won't overlap with nf_conn addresses.
Template allocation now does manual address alignment (see previous change)
on arches that don't have sufficent kmalloc min alignment.
Some spots intentionally use skb->_nfct instead of skb_nfct() helpers,
this is to avoid undoing the skb_nfct() use when we remove untracked
conntrack object in the future.
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
include/linux/skbuff.h | 21 +++++++++------------
include/net/netfilter/nf_conntrack.h | 11 ++++++-----
net/ipv6/netfilter/nf_dup_ipv6.c | 2 +-
net/netfilter/core.c | 2 +-
net/netfilter/nf_conntrack_core.c | 11 ++++++-----
net/netfilter/nf_conntrack_standalone.c | 3 +++
net/netfilter/xt_CT.c | 4 ++--
7 files changed, 28 insertions(+), 26 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 276431e047af..ac0bc085b139 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -585,7 +585,6 @@ static inline bool skb_mstamp_after(const struct skb_mstamp *t1,
* @cloned: Head may be cloned (check refcnt to be sure)
* @ip_summed: Driver fed us an IP checksum
* @nohdr: Payload reference only, must not modify header
- * @nfctinfo: Relationship of this skb to the connection
* @pkt_type: Packet class
* @fclone: skbuff clone status
* @ipvs_property: skbuff is owned by ipvs
@@ -594,7 +593,7 @@ static inline bool skb_mstamp_after(const struct skb_mstamp *t1,
* @nf_trace: netfilter packet trace flag
* @protocol: Packet protocol from driver
* @destructor: Destruct function
- * @nfct: Associated connection, if any
+ * @_nfct: Associated connection, if any (with nfctinfo bits)
* @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
* @skb_iif: ifindex of device we arrived on
* @tc_index: Traffic control index
@@ -668,7 +667,7 @@ struct sk_buff {
struct sec_path *sp;
#endif
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
- struct nf_conntrack *nfct;
+ unsigned long _nfct;
#endif
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
struct nf_bridge_info *nf_bridge;
@@ -721,7 +720,6 @@ struct sk_buff {
__u8 pkt_type:3;
__u8 pfmemalloc:1;
__u8 ignore_df:1;
- __u8 nfctinfo:3;
__u8 nf_trace:1;
__u8 ip_summed:2;
@@ -836,6 +834,7 @@ static inline bool skb_pfmemalloc(const struct sk_buff *skb)
#define SKB_DST_NOREF 1UL
#define SKB_DST_PTRMASK ~(SKB_DST_NOREF)
+#define SKB_NFCT_PTRMASK ~(7UL)
/**
* skb_dst - returns skb dst_entry
* @skb: buffer
@@ -3556,7 +3555,7 @@ static inline void skb_remcsum_process(struct sk_buff *skb, void *ptr,
static inline struct nf_conntrack *skb_nfct(const struct sk_buff *skb)
{
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
- return skb->nfct;
+ return (void *)(skb->_nfct & SKB_NFCT_PTRMASK);
#else
return NULL;
#endif
@@ -3590,8 +3589,8 @@ static inline void nf_bridge_get(struct nf_bridge_info *nf_bridge)
static inline void nf_reset(struct sk_buff *skb)
{
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
- nf_conntrack_put(skb->nfct);
- skb->nfct = NULL;
+ nf_conntrack_put(skb_nfct(skb));
+ skb->_nfct = 0;
#endif
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
nf_bridge_put(skb->nf_bridge);
@@ -3611,10 +3610,8 @@ static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src,
bool copy)
{
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
- dst->nfct = src->nfct;
- nf_conntrack_get(src->nfct);
- if (copy)
- dst->nfctinfo = src->nfctinfo;
+ dst->_nfct = src->_nfct;
+ nf_conntrack_get(skb_nfct(src));
#endif
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
dst->nf_bridge = src->nf_bridge;
@@ -3629,7 +3626,7 @@ static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src,
static inline void nf_copy(struct sk_buff *dst, const struct sk_buff *src)
{
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
- nf_conntrack_put(dst->nfct);
+ nf_conntrack_put(skb_nfct(dst));
#endif
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
nf_bridge_put(dst->nf_bridge);
diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h
index 06d3d2d24fe0..f540f9ad2af4 100644
--- a/include/net/netfilter/nf_conntrack.h
+++ b/include/net/netfilter/nf_conntrack.h
@@ -76,7 +76,7 @@ struct nf_conn {
/* Usage count in here is 1 for hash table, 1 per skb,
* plus 1 for any connection(s) we are `master' for
*
- * Hint, SKB address this struct and refcnt via skb->nfct and
+ * Hint, SKB address this struct and refcnt via skb->_nfct and
* helpers nf_conntrack_get() and nf_conntrack_put().
* Helper nf_ct_put() equals nf_conntrack_put() by dec refcnt,
* beware nf_ct_get() is different and don't inc refcnt.
@@ -164,13 +164,15 @@ int nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
const struct nf_conn *ignored_conntrack);
#define NFCT_INFOMASK 7UL
+#define NFCT_PTRMASK ~(NFCT_INFOMASK)
/* Return conntrack_info and tuple hash for given skb. */
static inline struct nf_conn *
nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo)
{
- *ctinfo = skb->nfctinfo;
- return (struct nf_conn *)skb->nfct;
+ *ctinfo = skb->_nfct & NFCT_INFOMASK;
+
+ return (struct nf_conn *)(skb->_nfct & NFCT_PTRMASK);
}
/* decrement reference count on a conntrack */
@@ -347,8 +349,7 @@ void nf_ct_tmpl_free(struct nf_conn *tmpl);
static inline void
nf_ct_set(struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info info)
{
- skb->nfct = &ct->ct_general;
- skb->nfctinfo = info;
+ skb->_nfct = (unsigned long)ct | info;
}
#define NF_CT_STAT_INC(net, count) __this_cpu_inc((net)->ct.stat->count)
diff --git a/net/ipv6/netfilter/nf_dup_ipv6.c b/net/ipv6/netfilter/nf_dup_ipv6.c
index ff04f6a7f45b..888ecd106e5f 100644
--- a/net/ipv6/netfilter/nf_dup_ipv6.c
+++ b/net/ipv6/netfilter/nf_dup_ipv6.c
@@ -59,7 +59,7 @@ void nf_dup_ipv6(struct net *net, struct sk_buff *skb, unsigned int hooknum,
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
nf_reset(skb);
nf_ct_set(skb, nf_ct_untracked_get(), IP_CT_NEW);
- nf_conntrack_get(skb->nfct);
+ nf_conntrack_get(skb_nfct(skb));
#endif
if (hooknum == NF_INET_PRE_ROUTING ||
hooknum == NF_INET_LOCAL_IN) {
diff --git a/net/netfilter/core.c b/net/netfilter/core.c
index ce6adfae521a..a87a6f8a74d8 100644
--- a/net/netfilter/core.c
+++ b/net/netfilter/core.c
@@ -375,7 +375,7 @@ void nf_ct_attach(struct sk_buff *new, const struct sk_buff *skb)
{
void (*attach)(struct sk_buff *, const struct sk_buff *);
- if (skb->nfct) {
+ if (skb->_nfct) {
rcu_read_lock();
attach = rcu_dereference(ip_ct_attach);
if (attach)
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 768968fba7f6..47c4ea53daa6 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -1239,7 +1239,7 @@ init_conntrack(struct net *net, struct nf_conn *tmpl,
return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
}
-/* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
+/* On success, returns conntrack ptr, sets skb->_nfct | ctinfo */
static inline struct nf_conn *
resolve_normal_ct(struct net *net, struct nf_conn *tmpl,
struct sk_buff *skb,
@@ -1323,7 +1323,7 @@ nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
NF_CT_STAT_INC_ATOMIC(net, ignore);
return NF_ACCEPT;
}
- skb->nfct = NULL;
+ skb->_nfct = 0;
}
/* rcu_read_lock()ed by nf_hook_thresh */
@@ -1352,7 +1352,7 @@ nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
goto out;
}
/* ICMP[v6] protocol trackers may assign one conntrack. */
- if (skb->nfct)
+ if (skb->_nfct)
goto out;
}
repeat:
@@ -1383,7 +1383,7 @@ nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
* the netfilter core what to do */
pr_debug("nf_conntrack_in: Can't track with proto module\n");
nf_conntrack_put(&ct->ct_general);
- skb->nfct = NULL;
+ skb->_nfct = 0;
NF_CT_STAT_INC_ATOMIC(net, invalid);
if (ret == -NF_DROP)
NF_CT_STAT_INC_ATOMIC(net, drop);
@@ -1878,7 +1878,8 @@ int nf_conntrack_init_start(void)
nf_conntrack_max = max_factor * nf_conntrack_htable_size;
nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
- sizeof(struct nf_conn), 0,
+ sizeof(struct nf_conn),
+ NFCT_INFOMASK + 1,
SLAB_DESTROY_BY_RCU | SLAB_HWCACHE_ALIGN, NULL);
if (!nf_conntrack_cachep)
goto err_cachep;
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index d009ae663453..2256147dcaad 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -642,6 +642,9 @@ static int __init nf_conntrack_standalone_init(void)
if (ret < 0)
goto out_start;
+ BUILD_BUG_ON(SKB_NFCT_PTRMASK != NFCT_PTRMASK);
+ BUILD_BUG_ON(NFCT_INFOMASK <= IP_CT_NUMBER);
+
#ifdef CONFIG_SYSCTL
nf_ct_netfilter_header =
register_net_sysctl(&init_net, "net", nf_ct_netfilter_table);
diff --git a/net/netfilter/xt_CT.c b/net/netfilter/xt_CT.c
index 51f00e1e1208..b008db0184b8 100644
--- a/net/netfilter/xt_CT.c
+++ b/net/netfilter/xt_CT.c
@@ -23,7 +23,7 @@
static inline int xt_ct_target(struct sk_buff *skb, struct nf_conn *ct)
{
/* Previously seen (loopback)? Ignore. */
- if (skb->nfct != NULL)
+ if (skb->_nfct != 0)
return XT_CONTINUE;
/* special case the untracked ct : we want the percpu object */
@@ -409,7 +409,7 @@ static unsigned int
notrack_tg(struct sk_buff *skb, const struct xt_action_param *par)
{
/* Previously seen (loopback)? Ignore. */
- if (skb->nfct != NULL)
+ if (skb->_nfct != 0)
return XT_CONTINUE;
nf_ct_set(skb, nf_ct_untracked_get(), IP_CT_NEW);
--
2.1.4
--
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