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Message-id: <1222962200.14079.19.camel@este>
Date: Thu, 02 Oct 2008 17:43:20 +0200
From: KOVACS Krisztian <hidden@....bme.hu>
To: David Miller <davem@...emloft.net>
Cc: kaber@...sh.net, netdev@...r.kernel.org,
netfilter-devel@...r.kernel.org
Subject: Re: [net-next PATCH 10/16] Don't lookup the socket if there's a socket
attached to the skb
Hi,
On Wed, 2008-10-01 at 08:51 -0700, David Miller wrote:
> From: KOVACS Krisztian <hidden@....bme.hu>
> Date: Wed, 01 Oct 2008 17:38:20 +0200
>
> > The problem is that if you include the if() test then you have to
> > include the lookup call as well and that's different for TCP/UDP.
>
> No, I only mean to make a helper for this construct:
>
> if (unlikely(skb->sk)) {
> ...
> }
>
> so, something like:
>
> static inline struct sock *sock_skb_steal(struct sk_buff *skb)
> {
> if (unlikely(skb->sk)) {
> struct sock *sk = skb->sk;
>
> skb->destructor = NULL;
> skb->sk = NULL;
> return sk;
> }
> return NULL;
> }
>
> and then also get rid of the ifdefs at the place where
> these calls are made (TCP and UDP).
Something like this?
- 8< -
Use the socket reference cached in the skb if present. The iptables
TPROXY rule for example does a socket lookup early and attaches the
socket reference to the skb. So in the respective TCP/UDP/DCCP rcv()
routine we don't do a lookup but simply steal the socket reference from
the skb.
Signed-off-by: KOVACS Krisztian <hidden@....bme.hu>
---
include/net/sock.h | 12 ++++++++++++
net/dccp/ipv4.c | 7 ++++---
net/dccp/ipv6.c | 9 +++++----
net/ipv4/tcp_ipv4.c | 6 ++++--
net/ipv4/udp.c | 5 +++--
net/ipv6/tcp_ipv6.c | 9 +++++----
net/ipv6/udp.c | 5 +++--
7 files changed, 36 insertions(+), 17 deletions(-)
diff --git a/include/net/sock.h b/include/net/sock.h
index 75a312d..b60fdc1 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1324,6 +1324,18 @@ static inline void sk_change_net(struct sock *sk, struct net *net)
sock_net_set(sk, hold_net(net));
}
+static inline struct sock *sock_skb_steal(struct sk_buff *skb)
+{
+ if (unlikely(skb->sk)) {
+ struct sock *sk = skb->sk;
+
+ skb->destructor = NULL;
+ skb->sk = NULL;
+ return sk;
+ }
+ return NULL;
+}
+
extern void sock_enable_timestamp(struct sock *sk);
extern int sock_get_timestamp(struct sock *, struct timeval __user *);
extern int sock_get_timestampns(struct sock *, struct timespec __user *);
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index 882c5c4..6968ac8 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -811,9 +811,10 @@ static int dccp_v4_rcv(struct sk_buff *skb)
/* Step 2:
* Look up flow ID in table and get corresponding socket */
- sk = __inet_lookup(dev_net(skb->dst->dev), &dccp_hashinfo,
- iph->saddr, dh->dccph_sport,
- iph->daddr, dh->dccph_dport, inet_iif(skb));
+ if (likely((sk = sock_skb_steal(skb)) == NULL))
+ sk = __inet_lookup(dev_net(skb->dst->dev), &dccp_hashinfo,
+ iph->saddr, dh->dccph_sport,
+ iph->daddr, dh->dccph_dport, inet_iif(skb));
/*
* Step 2:
* If no socket ...
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index 5e1ee0d..97d1405 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -805,10 +805,11 @@ static int dccp_v6_rcv(struct sk_buff *skb)
/* Step 2:
* Look up flow ID in table and get corresponding socket */
- sk = __inet6_lookup(dev_net(skb->dst->dev), &dccp_hashinfo,
- &ipv6_hdr(skb)->saddr, dh->dccph_sport,
- &ipv6_hdr(skb)->daddr, ntohs(dh->dccph_dport),
- inet6_iif(skb));
+ if (likely((sk = sock_skb_steal(skb)) == NULL))
+ sk = __inet6_lookup(dev_net(skb->dst->dev), &dccp_hashinfo,
+ &ipv6_hdr(skb)->saddr, dh->dccph_sport,
+ &ipv6_hdr(skb)->daddr, ntohs(dh->dccph_dport),
+ inet6_iif(skb));
/*
* Step 2:
* If no socket ...
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 1ac4d05..e879037 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1577,8 +1577,10 @@ int tcp_v4_rcv(struct sk_buff *skb)
TCP_SKB_CB(skb)->flags = iph->tos;
TCP_SKB_CB(skb)->sacked = 0;
- sk = __inet_lookup(net, &tcp_hashinfo, iph->saddr,
- th->source, iph->daddr, th->dest, inet_iif(skb));
+ if (likely((sk = sock_skb_steal(skb)) == NULL))
+ sk = __inet_lookup(net, &tcp_hashinfo, iph->saddr,
+ th->source, iph->daddr, th->dest, inet_iif(skb));
+
if (!sk)
goto no_tcp_socket;
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 28c3c31..874bceb 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1198,8 +1198,9 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct hlist_head udptable[],
return __udp4_lib_mcast_deliver(net, skb, uh,
saddr, daddr, udptable);
- sk = __udp4_lib_lookup(net, saddr, uh->source, daddr,
- uh->dest, inet_iif(skb), udptable);
+ if (likely((sk = sock_skb_steal(skb)) == NULL))
+ sk = __udp4_lib_lookup(net, saddr, uh->source, daddr,
+ uh->dest, inet_iif(skb), udptable);
if (sk != NULL) {
int ret = 0;
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index e85f377..c44b6d7 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1681,10 +1681,11 @@ static int tcp_v6_rcv(struct sk_buff *skb)
TCP_SKB_CB(skb)->flags = ipv6_get_dsfield(ipv6_hdr(skb));
TCP_SKB_CB(skb)->sacked = 0;
- sk = __inet6_lookup(net, &tcp_hashinfo,
- &ipv6_hdr(skb)->saddr, th->source,
- &ipv6_hdr(skb)->daddr, ntohs(th->dest),
- inet6_iif(skb));
+ if (likely((sk = sock_skb_steal(skb)) == NULL))
+ sk = __inet6_lookup(net, &tcp_hashinfo,
+ &ipv6_hdr(skb)->saddr, th->source,
+ &ipv6_hdr(skb)->daddr, ntohs(th->dest),
+ inet6_iif(skb));
if (!sk)
goto no_tcp_socket;
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index a6aecf7..e2741aa 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -488,8 +488,9 @@ int __udp6_lib_rcv(struct sk_buff *skb, struct hlist_head udptable[],
* check socket cache ... must talk to Alan about his plans
* for sock caches... i'll skip this for now.
*/
- sk = __udp6_lib_lookup(net, saddr, uh->source,
- daddr, uh->dest, inet6_iif(skb), udptable);
+ if (likely((sk = sock_skb_steal(skb)) == NULL))
+ sk = __udp6_lib_lookup(net, saddr, uh->source,
+ daddr, uh->dest, inet6_iif(skb), udptable);
if (sk == NULL) {
if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
--
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