From a9e419dc7be6997409dca6d1b9daf3cc7046902f Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Mon, 23 Jan 2017 18:21:59 +0100 Subject: [PATCH] netfilter: merge ctinfo into nfct pointer storage area 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 Signed-off-by: Pablo Neira Ayuso --- 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 @@ repeat: * 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); -- 2.30.2