From a0f82f64e26929776c58a5c93c2ecb38e3d82815 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Sun, 19 Apr 2009 09:43:48 +0000 Subject: [PATCH] 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 Signed-off-by: David S. Miller --- include/linux/tcp.h | 4 +--- include/net/tcp.h | 13 +++++++++++++ net/ipv4/syncookies.c | 5 ++--- net/ipv6/syncookies.c | 4 ++-- 4 files changed, 18 insertions(+), 8 deletions(-) diff --git a/include/linux/tcp.h b/include/linux/tcp.h index 9d5078bd23a3..8afac76cd748 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 1b94b9bfe2dc..b55b4891029e 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 b35a950d2e06..cd2b97f1b6e1 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 711175e0571f..8c2513982b61 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; -- 2.30.2