netdev - Re: [PATCH v2 1/2] tcp: setup timestamp offset when write

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Date:   Wed, 22 Feb 2017 17:31:47 +0300
From:   Alexey Kodanev <alexey.kodanev@...cle.com>
To:     Eric Dumazet <eric.dumazet@...il.com>
Cc:     David Miller <davem@...emloft.net>,
        netdev <netdev@...r.kernel.org>, Florian Westphal <fw@...len.de>,
        Eric Dumazet <edumazet@...gle.com>
Subject: Re: [PATCH v2 1/2] tcp: setup timestamp offset when write_seq already
 set

On 02/22/2017 04:17 PM, Eric Dumazet wrote:
> On Wed, 2017-02-22 at 13:23 +0300, Alexey Kodanev wrote:
>> ...
>>
>> diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
>> index fe9da4f..c5169b8 100644
>> --- a/net/ipv4/tcp_ipv4.c
>> +++ b/net/ipv4/tcp_ipv4.c
>> @@ -145,6 +145,7 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
>>  	struct flowi4 *fl4;
>>  	struct rtable *rt;
>>  	int err;
>> +	u32 seq;
>>  	struct ip_options_rcu *inet_opt;
>>  
>>  	if (addr_len < sizeof(struct sockaddr_in))
>> @@ -232,12 +233,15 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
>>  	sk->sk_gso_type = SKB_GSO_TCPV4;
>>  	sk_setup_caps(sk, &rt->dst);
>>  
>> -	if (!tp->write_seq && likely(!tp->repair))
>> -		tp->write_seq = secure_tcp_sequence_number(inet->inet_saddr,
>> -							   inet->inet_daddr,
>> -							   inet->inet_sport,
>> -							   usin->sin_port,
>> -							   &tp->tsoffset);
>> +	if (likely(!tp->repair)) {
>> +		seq = secure_tcp_sequence_number(inet->inet_saddr,
>> +						 inet->inet_daddr,
>> +						 inet->inet_sport,
>> +						 usin->sin_port,
>> +						 &tp->tsoffset);
>> +		if (!tp->write_seq)
>> +			tp->write_seq = seq;
>> +	}
>>  
> Nice catch !
>
> secure_tcp_sequence_number() could be renamed, because it has two
> purposes really.

What about "secure_tcp_seq_and_tsoff(...)" ?

Also,

tcp_v4_init_sequence(...) -> tcp_v4_init_seq_and_tsoff(...)
tcp_v6_init_sequence(...) -> tcp_v6_init_seq_and_tsoff(...)


Thanks,
Alexey