Re: [PATCH 1/3][v2] tcp: fix ICMP-RTO war: Check lower bound

[David Miller <davem@davemloft.net>]

From: Damian Lukowski <damian@tvk.rwth-aachen.de>
Date: Fri, 29 Jan 2010 23:15:54 +0100

> diff --git a/include/net/tcp.h b/include/net/tcp.h
> index 34f5cc2..ff6cbaa 100644
> --- a/include/net/tcp.h
> +++ b/include/net/tcp.h
> @@ -528,9 +528,12 @@ static inline void tcp_bound_rto(const struct sock *sk)
>  		inet_csk(sk)->icsk_rto = TCP_RTO_MAX;
>  }
>  
> +static inline u32 tcp_rto_min(struct sock *sk);
>  static inline u32 __tcp_set_rto(const struct tcp_sock *tp)
>  {
> -	return (tp->srtt >> 3) + tp->rttvar;
> +	u32 rto = (tp->srtt >> 3) + tp->rttvar;
> +	u32 min = tcp_rto_min((struct sock *)tp);
> +	return unlikely(rto < min) ? min : rto;
>  }
>  
>  static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd)

Don't make assumptions about the layout and relationships
between struct sock and struct tcp_sock without using
the interfaces create for this purpose.

For this case, simply add a "struct sock *" first argument to
__tcp_set_rto() and update the callers.

Thanks.