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Message-ID: <20240115205514.68364-2-kuniyu@amazon.com>
Date: Mon, 15 Jan 2024 12:55:09 -0800
From: Kuniyuki Iwashima <kuniyu@...zon.com>
To: Eric Dumazet <edumazet@...gle.com>, Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>, Andrii Nakryiko <andrii@...nel.org>,
Martin KaFai Lau <martin.lau@...ux.dev>, Paolo Abeni <pabeni@...hat.com>
CC: Kuniyuki Iwashima <kuniyu@...zon.com>, Kuniyuki Iwashima
<kuni1840@...il.com>, <bpf@...r.kernel.org>, <netdev@...r.kernel.org>
Subject: [PATCH v8 bpf-next 1/6] tcp: Move tcp_ns_to_ts() to tcp.h
We will support arbitrary SYN Cookie with BPF.
When BPF prog validates ACK and kfunc allocates a reqsk, we need
to call tcp_ns_to_ts() to calculate an offset of TSval for later
use:
time
t0 : Send SYN+ACK
-> tsval = Initial TSval (Random Number)
t1 : Recv ACK of 3WHS
-> tsoff = TSecr - tcp_ns_to_ts(usec_ts_ok, tcp_clock_ns())
= Initial TSval - t1
t2 : Send ACK
-> tsval = t2 + tsoff
= Initial TSval + (t2 - t1)
= Initial TSval + Time Delta (x)
(x) Note that the time delta does not include the initial RTT
from t0 to t1.
Let's move tcp_ns_to_ts() to tcp.h.
Signed-off-by: Kuniyuki Iwashima <kuniyu@...zon.com>
Reviewed-by: Eric Dumazet <edumazet@...gle.com>
---
include/net/tcp.h | 9 +++++++++
net/ipv4/syncookies.c | 9 ---------
2 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/include/net/tcp.h b/include/net/tcp.h
index dd78a1181031..114000e71a46 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -577,6 +577,15 @@ static inline u32 tcp_cookie_time(void)
return val;
}
+/* Convert one nsec 64bit timestamp to ts (ms or usec resolution) */
+static inline u64 tcp_ns_to_ts(bool usec_ts, u64 val)
+{
+ if (usec_ts)
+ return div_u64(val, NSEC_PER_USEC);
+
+ return div_u64(val, NSEC_PER_MSEC);
+}
+
u32 __cookie_v4_init_sequence(const struct iphdr *iph, const struct tcphdr *th,
u16 *mssp);
__u32 cookie_v4_init_sequence(const struct sk_buff *skb, __u16 *mss);
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index 61f1c96cfe63..981944c22820 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -51,15 +51,6 @@ static u32 cookie_hash(__be32 saddr, __be32 daddr, __be16 sport, __be16 dport,
count, &syncookie_secret[c]);
}
-/* Convert one nsec 64bit timestamp to ts (ms or usec resolution) */
-static u64 tcp_ns_to_ts(bool usec_ts, u64 val)
-{
- if (usec_ts)
- return div_u64(val, NSEC_PER_USEC);
-
- return div_u64(val, NSEC_PER_MSEC);
-}
-
/*
* when syncookies are in effect and tcp timestamps are enabled we encode
* tcp options in the lower bits of the timestamp value that will be
--
2.30.2
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