> On Jun 1, 2019, at 6:09 PM, Martin Lau <kafai@xxxxxx> wrote:
>
> On Sat, Jun 01, 2019 at 04:54:46PM -0700, Song Liu wrote:
>>
>>
>>> On May 31, 2019, at 3:29 PM, Martin KaFai Lau <kafai@xxxxxx> wrote:
>>>
>>> When the commit a6024562ffd7 ("udp: Add GRO functions to UDP socket")
>>> added udp[46]_lib_lookup_skb to the udp_gro code path, it broke
>>> the reuseport_select_sock() assumption that skb->data is pointing
>>> to the transport header.
>>>
>>> This patch follows an earlier __udp6_lib_err() fix by
>>> passing a NULL skb to avoid calling the reuseport's bpf_prog.
>>>
>>> Fixes: a6024562ffd7 ("udp: Add GRO functions to UDP socket")
>>> Cc: Tom Herbert <tom@xxxxxxxxxxxxxxx>
>>> Signed-off-by: Martin KaFai Lau <kafai@xxxxxx>
>>> ---
>>> net/ipv4/udp.c | 6 +++++-
>>> net/ipv6/udp.c | 2 +-
>>> 2 files changed, 6 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
>>> index 8fb250ed53d4..85db0e3d7f3f 100644
>>> --- a/net/ipv4/udp.c
>>> +++ b/net/ipv4/udp.c
>>> @@ -503,7 +503,11 @@ static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb,
> Note that this patch is changing the below "udp4_lib_lookup_skb()"
> instead of the above "__udp4_lib_lookup_skb()".
>
>>> struct sock *udp4_lib_lookup_skb(struct sk_buff *skb,
>>> __be16 sport, __be16 dport)
>>> {
>>> - return __udp4_lib_lookup_skb(skb, sport, dport, &udp_table);
>>> + const struct iphdr *iph = ip_hdr(skb);
>>> +
>>> + return __udp4_lib_lookup(dev_net(skb->dev), iph->saddr, sport,
>>> + iph->daddr, dport, inet_iif(skb),
>>> + inet_sdif(skb), &udp_table, NULL);
>>
>> I think we can now remove the last argument of __udp4_lib_lookup()?
> The last arg of __udp4_lib_lookup() is skb.
> __udp4_lib_lookup_skb(), which is not changed in this patch, is still
> calling __udp4_lib_lookup() with a skb and the skb is used by the
> reuseport's bpf_prog. Hence, it cannot be removed.
I see. I somehow missed this path. Thanks for the explanation.
Acked-by: Song Liu <songliubraving@xxxxxx>
>
>>
>>
>>> }
>>> EXPORT_SYMBOL_GPL(udp4_lib_lookup_skb);
>>>
>>> diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
>>> index 133e6370f89c..4e52c37bb836 100644
>>> --- a/net/ipv6/udp.c
>>> +++ b/net/ipv6/udp.c
>>> @@ -243,7 +243,7 @@ struct sock *udp6_lib_lookup_skb(struct sk_buff *skb,
>>>
>>> return __udp6_lib_lookup(dev_net(skb->dev), &iph->saddr, sport,
>>> &iph->daddr, dport, inet6_iif(skb),
>>> - inet6_sdif(skb), &udp_table, skb);
>>> + inet6_sdif(skb), &udp_table, NULL);
>>> }
>>> EXPORT_SYMBOL_GPL(udp6_lib_lookup_skb);
>>>
>>> --
>>> 2.17.1
>>>
>>
