On Mon, Jun 18, 2018 at 08:44:17AM -0600, Arnd Bergmann wrote:
> The nes infiniband driver uses current_kernel_time() to get a nanosecond
> granunarity timestamp to initialize its tcp sequence counters. This is
> one of only a few remaining users of that deprecated function, so we
> should try to get rid of it.
>
> Aside from using a deprecated API, there are several problems I see here:
>
> - Using a CLOCK_REALTIME based time source makes it predictable in
> case the time base is synchronized.
> - Using a coarse timestamp means it only gets updated once per jiffie,
> making it even more predictable in order to avoid having to access
> the hardware clock source
> - The upper 2 bits are always zero because the nanoseconds are at most
> 999999999.
>
> For the Linux TCP implementation, we use secure_tcp_seq(), which appears
> to be appropriate here as well, and solves all the above problems.
>
> I'm doing the same change in both versions of the nes driver, with
> i40iw being a later copy of the same code.
>
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
Thanks Arnd for the patch!
[...]
> @@ -2164,7 +2165,6 @@ static struct i40iw_cm_node *i40iw_make_cm_node(
> struct i40iw_cm_listener *listener)
> {
> struct i40iw_cm_node *cm_node;
> - struct timespec ts;
> int oldarpindex;
> int arpindex;
> struct net_device *netdev = iwdev->netdev;
> @@ -2214,8 +2214,10 @@ static struct i40iw_cm_node *i40iw_make_cm_node(
> cm_node->tcp_cntxt.rcv_wscale = I40IW_CM_DEFAULT_RCV_WND_SCALE;
> cm_node->tcp_cntxt.rcv_wnd =
> I40IW_CM_DEFAULT_RCV_WND_SCALED >>
> I40IW_CM_DEFAULT_RCV_WND_SCALE;
> - ts = current_kernel_time();
> - cm_node->tcp_cntxt.loc_seq_num = ts.tv_nsec;
> + cm_node->tcp_cntxt.loc_seq_num =
> secure_tcp_seq(htonl(cm_node->loc_addr[0]),
> +
> htonl(cm_node->rem_addr[0]),
> +
> htons(cm_node->loc_port),
> +
> htons(cm_node->rem_port));
Should we not be using secure_tcpv6_seq() when we are ipv6?
Shiraz
> cm_node->tcp_cntxt.mss = (cm_node->ipv4) ? (iwdev->vsi.mtu -
> I40IW_MTU_TO_MSS_IPV4) :
> (iwdev->vsi.mtu - I40IW_MTU_TO_MSS_IPV6);
>
>
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