On Mon, Oct 16, 2017 at 2:55 PM, David Ahern <[email protected]> wrote:
> On 10/16/17 3:46 PM, Cong Wang wrote:
>> Well, for NULL case, the entry->saddr_v6 will not be filled with
>> your patch.
>
> I think you meant daddr_v6 and yes it will not get filled in, but 0 is
> better than a panic ;-)
>
Sure, but we can do even better with sk->sk_v6_daddr.
>>
>> How about using sk->sk_v6_daddr?
>>
>
> That works, but then both addresses should come from sk and not np:
Yes.
>
> diff --git a/include/trace/events/tcp.h b/include/trace/events/tcp.h
> index 1ffab6d96e94..7989c2dcedf1 100644
> --- a/include/trace/events/tcp.h
> +++ b/include/trace/events/tcp.h
> @@ -46,9 +46,9 @@ TRACE_EVENT(tcp_retransmit_skb,
>
> if (np) {
> pin6 = (struct in6_addr *)__entry->saddr_v6;
> - *pin6 = np->saddr;
> + *pin6 = sk->sk_v6_rcv_saddr;
> pin6 = (struct in6_addr *)__entry->daddr_v6;
> - *pin6 = *(np->daddr_cache);
> + *pin6 = sk->sk_v6_daddr;
> } else {
> pin6 = (struct in6_addr *)__entry->saddr_v6;
> ipv6_addr_set_v4mapped(inet->inet_saddr, pin6);
>
>
> So np is just a trigger for IPv6 versus v4 mapped.
>
> I do have a question about why ipv4 addresses are non-NULL:
If you really mean non-NULL, they are addresses, not pointers to
addresses.
Or if you mean non-zero, they are set to LOOPBACK4_IPV6
which is what I expect.
