Subject: Re: [PATCH 2/2] ipv6: use sk_v6_copy_addrs when memcpy struct ipv6_pinfo

From: wangweidong <[email-masked]>
Date: Tue, 19 Nov 2013 12:38:39 +0800

On 2013/11/19 11:55, Eric Dumazet wrote:
> On Tue, 2013-11-19 at 10:47 +0800, Wang Weidong wrote:
>> commit efe4208f ("ipv6: make lookups simpler and faster") remove
>> the daddr and rcv_saddr from struct ipv6_pinfo. When use memcpy
>> the ipv6_pinfo, we lose the sk_v6_daddr and sk_v6_rcv_saddr, so
>> use the sk_v6_copy_addrs when needed.
>>
>> Signed-off-by: Wang Weidong <[email-masked]>
>> ---
>>  net/dccp/ipv6.c     | 4 ++++
>>  net/ipv6/tcp_ipv6.c | 4 ++++
>>  net/sctp/ipv6.c     | 4 ++++
>>  3 files changed, 12 insertions(+)
>>
>> diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
>> index 4ac71ff..90182a8 100644
>> --- a/net/dccp/ipv6.c
>> +++ b/net/dccp/ipv6.c
>> @@ -465,6 +465,10 @@ static struct sock *dccp_v6_request_recv_sock(struct sock *sk,
>>  		newnp = inet6_sk(newsk);
>>  
>>  		memcpy(newnp, np, sizeof(struct ipv6_pinfo));
>> +		/* Don't forget copy the rcv_saddr and daddr when
>> +		 * copy ipv6_pinfo.
>> +		 */
>> +		sk_v6_copy_addrs(newsk, sk);
>>  
>>  		ipv6_addr_set_v4mapped(newinet->inet_daddr, &newsk->sk_v6_daddr);
>>  
>> diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
>> index 0740f93..83d011e 100644
>> --- a/net/ipv6/tcp_ipv6.c
>> +++ b/net/ipv6/tcp_ipv6.c
>> @@ -1116,6 +1116,10 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
>>  		newtp = tcp_sk(newsk);
>>  
>>  		memcpy(newnp, np, sizeof(struct ipv6_pinfo));
>> +		/* Don't forget copy the rcv_saddr and daddr when
>> +		 * copy ipv6_pinfo.
>> +		 */
>> +		sk_v6_copy_addrs(newsk, sk);
>>  
>>  		ipv6_addr_set_v4mapped(newinet->inet_daddr, &newsk->sk_v6_daddr);
>>  
> 
> 
> No idea why this patch is needed for TCP.
> (btw you deal with v4mapped here, no mention of it in the changelog)
> 
> The fields were moved into generic socket, and generic socket is copied.
> 
> Are you seeing a real bug ?
> 
> Please elaborate, thanks !
> 

Hm, You are right. I am not careful to look over the generic socket whether it would be
copied. Sorry for that.
Thanks.