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authorIlpo Järvinen <ilpo.jarvinen@helsinki.fi>2009-03-14 14:23:03 +0000
committerDavid S. Miller <davem@davemloft.net>2009-03-15 20:09:52 -0700
commitc887e6d2d9aee56ee7c9f2af4cec3a5efdcc4c72 (patch)
treeee267baadce309166ceea5649292f221cd9a6766
parentc43d558a5139a3b22dcac3f19f64ecb39130b02e (diff)
tcp: consolidate paws check
Wow, it was quite tricky to merge that stream of negations but I think I finally got it right: check & replace_ts_recent: (s32)(rcv_tsval - ts_recent) >= 0 => 0 (s32)(ts_recent - rcv_tsval) <= 0 => 0 discard: (s32)(ts_recent - rcv_tsval) > TCP_PAWS_WINDOW => 1 (s32)(ts_recent - rcv_tsval) <= TCP_PAWS_WINDOW => 0 I toggled the return values of tcp_paws_check around since the old encoding added yet-another negation making tracking of truth-values really complicated. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/net/tcp.h18
-rw-r--r--net/ipv4/tcp_input.c11
-rw-r--r--net/ipv4/tcp_minisocks.c4
3 files changed, 21 insertions, 12 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h
index d74ac301e6b..255ca35bea0 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -997,11 +997,21 @@ static inline int tcp_fin_time(const struct sock *sk)
return fin_timeout;
}
-static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst)
+static inline int tcp_paws_check(const struct tcp_options_received *rx_opt,
+ int paws_win)
{
- if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0)
- return 0;
- if (get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS)
+ if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win)
+ return 1;
+ if (unlikely(get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS))
+ return 1;
+
+ return 0;
+}
+
+static inline int tcp_paws_reject(const struct tcp_options_received *rx_opt,
+ int rst)
+{
+ if (tcp_paws_check(rx_opt, 0))
return 0;
/* RST segments are not recommended to carry timestamp,
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index f527a16a7b3..b7d02c5dd6d 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3883,8 +3883,7 @@ static inline void tcp_replace_ts_recent(struct tcp_sock *tp, u32 seq)
* Not only, also it occurs for expired timestamps.
*/
- if ((s32)(tp->rx_opt.rcv_tsval - tp->rx_opt.ts_recent) >= 0 ||
- get_seconds() >= tp->rx_opt.ts_recent_stamp + TCP_PAWS_24DAYS)
+ if (tcp_paws_check(&tp->rx_opt, 0))
tcp_store_ts_recent(tp);
}
}
@@ -3936,9 +3935,9 @@ static inline int tcp_paws_discard(const struct sock *sk,
const struct sk_buff *skb)
{
const struct tcp_sock *tp = tcp_sk(sk);
- return ((s32)(tp->rx_opt.ts_recent - tp->rx_opt.rcv_tsval) > TCP_PAWS_WINDOW &&
- get_seconds() < tp->rx_opt.ts_recent_stamp + TCP_PAWS_24DAYS &&
- !tcp_disordered_ack(sk, skb));
+
+ return !tcp_paws_check(&tp->rx_opt, TCP_PAWS_WINDOW) &&
+ !tcp_disordered_ack(sk, skb);
}
/* Check segment sequence number for validity.
@@ -5513,7 +5512,7 @@ discard:
/* PAWS check. */
if (tp->rx_opt.ts_recent_stamp && tp->rx_opt.saw_tstamp &&
- tcp_paws_check(&tp->rx_opt, 0))
+ tcp_paws_reject(&tp->rx_opt, 0))
goto discard_and_undo;
if (th->syn) {
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 4b0df3e6b60..43bbba7926e 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -107,7 +107,7 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb,
if (tmp_opt.saw_tstamp) {
tmp_opt.ts_recent = tcptw->tw_ts_recent;
tmp_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
- paws_reject = tcp_paws_check(&tmp_opt, th->rst);
+ paws_reject = tcp_paws_reject(&tmp_opt, th->rst);
}
}
@@ -511,7 +511,7 @@ struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb,
* from another data.
*/
tmp_opt.ts_recent_stamp = get_seconds() - ((TCP_TIMEOUT_INIT/HZ)<<req->retrans);
- paws_reject = tcp_paws_check(&tmp_opt, th->rst);
+ paws_reject = tcp_paws_reject(&tmp_opt, th->rst);
}
}