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authorFlorian Westphal <fw@strlen.de>2009-04-19 09:43:48 +0000
committerDavid S. Miller <davem@davemloft.net>2009-04-20 02:25:26 -0700
commita0f82f64e26929776c58a5c93c2ecb38e3d82815 (patch)
tree8c39812fc6fc8133cc28944e38b44c941d8fa3ce
parent7eebb0b28f755e297d355a205bb04945b256db6b (diff)
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syncookies: remove last_synq_overflow from struct tcp_sock
last_synq_overflow eats 4 or 8 bytes in struct tcp_sock, even though it is only used when a listening sockets syn queue is full. We can (ab)use rx_opt.ts_recent_stamp to store the same information; it is not used otherwise as long as a socket is in listen state. Move linger2 around to avoid splitting struct mtu_probe across cacheline boundary on 32 bit arches. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/linux/tcp.h4
-rw-r--r--include/net/tcp.h13
-rw-r--r--net/ipv4/syncookies.c5
-rw-r--r--net/ipv6/syncookies.c4
4 files changed, 18 insertions, 8 deletions
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 9d5078b..8afac76 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -377,7 +377,7 @@ struct tcp_sock {
unsigned int keepalive_time; /* time before keep alive takes place */
unsigned int keepalive_intvl; /* time interval between keep alive probes */
- unsigned long last_synq_overflow;
+ int linger2;
/* Receiver side RTT estimation */
struct {
@@ -406,8 +406,6 @@ struct tcp_sock {
/* TCP MD5 Signagure Option information */
struct tcp_md5sig_info *md5sig_info;
#endif
-
- int linger2;
};
static inline struct tcp_sock *tcp_sk(const struct sock *sk)
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 1b94b9b..b55b489 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -265,6 +265,19 @@ static inline int tcp_too_many_orphans(struct sock *sk, int num)
atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2]);
}
+/* syncookies: remember time of last synqueue overflow */
+static inline void tcp_synq_overflow(struct sock *sk)
+{
+ tcp_sk(sk)->rx_opt.ts_recent_stamp = jiffies;
+}
+
+/* syncookies: no recent synqueue overflow on this listening socket? */
+static inline int tcp_synq_no_recent_overflow(const struct sock *sk)
+{
+ unsigned long last_overflow = tcp_sk(sk)->rx_opt.ts_recent_stamp;
+ return time_after(jiffies, last_overflow + TCP_TIMEOUT_INIT);
+}
+
extern struct proto tcp_prot;
#define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field)
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index b35a950..cd2b97f 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -161,13 +161,12 @@ static __u16 const msstab[] = {
*/
__u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb, __u16 *mssp)
{
- struct tcp_sock *tp = tcp_sk(sk);
const struct iphdr *iph = ip_hdr(skb);
const struct tcphdr *th = tcp_hdr(skb);
int mssind;
const __u16 mss = *mssp;
- tp->last_synq_overflow = jiffies;
+ tcp_synq_overflow(sk);
/* XXX sort msstab[] by probability? Binary search? */
for (mssind = 0; mss > msstab[mssind + 1]; mssind++)
@@ -268,7 +267,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
if (!sysctl_tcp_syncookies || !th->ack)
goto out;
- if (time_after(jiffies, tp->last_synq_overflow + TCP_TIMEOUT_INIT) ||
+ if (tcp_synq_no_recent_overflow(sk) ||
(mss = cookie_check(skb, cookie)) == 0) {
NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_SYNCOOKIESFAILED);
goto out;
diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c
index 711175e..8c25139 100644
--- a/net/ipv6/syncookies.c
+++ b/net/ipv6/syncookies.c
@@ -131,7 +131,7 @@ __u32 cookie_v6_init_sequence(struct sock *sk, struct sk_buff *skb, __u16 *mssp)
int mssind;
const __u16 mss = *mssp;
- tcp_sk(sk)->last_synq_overflow = jiffies;
+ tcp_synq_overflow(sk);
for (mssind = 0; mss > msstab[mssind + 1]; mssind++)
;
@@ -175,7 +175,7 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
if (!sysctl_tcp_syncookies || !th->ack)
goto out;
- if (time_after(jiffies, tp->last_synq_overflow + TCP_TIMEOUT_INIT) ||
+ if (tcp_synq_no_recent_overflow(sk) ||
(mss = cookie_check(skb, cookie)) == 0) {
NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_SYNCOOKIESFAILED);
goto out;