From: Nicolas Dichtel <nicolas.dichtel@6wind•com>
To: Julian Anastasov <ja@ssi•bg>
Cc: hannes@stressinduktion•org, netdev@vger•kernel.org,
davem@davemloft•net, David.Laight@ACULAB•COM, jiri@resnulli•us,
vyasevich@gmail•com, kuznet@ms2•inr.ac.ru, jmorris@namei•org,
yoshfuji@linux-ipv6•org, kaber@trash•net, thaller@redhat•com,
stephen@networkplumber•org
Subject: Re: [RFC PATCH net-next 2/2] udp: add sk opt to allow sending pkt with src 0.0.0.0
Date: Tue, 12 Nov 2013 09:59:16 +0100 [thread overview]
Message-ID: <5281EDE4.3080704@6wind.com> (raw)
In-Reply-To: <alpine.LFD.2.03.1311091610090.1411@ssi.bg>
Le 09/11/2013 15:46, Julian Anastasov a écrit :
>
> Hello,
>
> On Sat, 9 Nov 2013, Nicolas Dichtel wrote:
>
>> This feature allows to a send packets with address source set to 0.0.0.0 even if
>> an ip address is available on another interface.
>>
>> It's useful for DHCP client, to allow them to use UDP sockets and be compliant
>> with the RFC2131, Section 4.1:
>>
>> 4.1 Constructing and sending DHCP messages
>> ...
>> DHCP messages broadcast by a client prior to that client obtaining
>> its IP address must have the source address field in the IP header
>> set to 0.
>>
>> Based on a previous work from
>> Guillaume Gaudonville <guillaume.gaudonville@6wind•com>.
>>
>> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind•com>
>
> ...
>
>> diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
>> index 89909dd730dd..f58945187dbd 100644
>> --- a/net/ipv4/udp.c
>> +++ b/net/ipv4/udp.c
>
> ...
>
>> + if (up->src_any && sk->sk_bound_dev_if) {
>> + struct net_device *dev;
>> + struct in_device *in_dev;
>> +
>> + rcu_read_lock();
>> + dev = dev_get_by_index_rcu(sock_net(sk), sk->sk_bound_dev_if);
>> + in_dev = dev ? __in_dev_get_rcu(dev) : NULL;
>> + if (!inet_confirm_addr(sock_net(sk), in_dev, 0, 0,
>> + RT_SCOPE_HOST))
>
> I don't have an opinion about UDP_SRC_ANY, just some
> comments...
>
> Can a simple !in_dev->ifa_list check replace the
> !inet_confirm_addr call? Looking at __inet_insert_ifa()
> it seems only 0.0.0.0 does not add an ifa. Long ago
> adding 0.0.0.0 was a way to create in_dev for dev but
> now in_dev is created on device registration, i.e. even
> before addresses are added.
>
> For the first patch, may be it is not needed.
> We have two choices:
>
> 1. Do not change args and just fix comments. Of course,
> it is tricky to use this function by using scope instead
> of in_dev as a key for device-specific matching because
> such interface is confusing.
I hesitated to take this choice, but I think that keeping the
original behavior is better.
>
> 2. Add 'net' arg and use in_dev as explained in my
> previous email. Not sure if changing args of exported
> function is acceptable.
FWIK, it's not a problem.
Regards,
Nicolas
next prev parent reply other threads:[~2013-11-12 8:59 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-24 13:45 [patch net-next] ipv6: allow userspace to create address with IFLA_F_TEMPORARY flag Jiri Pirko
2013-10-24 13:48 ` [patch iproute2] allow to create temporary addresses Jiri Pirko
2013-10-24 14:02 ` [patch net-next] ipv6: allow userspace to create address with IFLA_F_TEMPORARY flag Hannes Frederic Sowa
2013-10-24 16:59 ` Jiri Pirko
2013-10-25 10:05 ` Vladislav Yasevich
2013-10-25 20:12 ` Hannes Frederic Sowa
2013-10-25 23:05 ` Vladislav Yasevich
2013-10-27 13:29 ` Jiri Pirko
2013-10-27 16:48 ` Hannes Frederic Sowa
2013-10-28 13:56 ` Vladislav Yasevich
2013-10-28 21:17 ` David Miller
2013-10-28 23:16 ` Dan Williams
2013-10-28 23:23 ` Dan Williams
2013-10-29 0:12 ` David Miller
2013-10-28 23:48 ` Hannes Frederic Sowa
2013-10-29 14:31 ` Dan Williams
2013-10-29 14:38 ` Hannes Frederic Sowa
2013-10-29 17:21 ` Dan Williams
2013-10-29 16:58 ` Vlad Yasevich
2013-10-29 17:15 ` Dan Williams
2013-10-29 0:08 ` David Miller
2013-10-29 0:13 ` Hannes Frederic Sowa
2013-10-29 0:46 ` David Miller
2013-10-28 23:31 ` Hannes Frederic Sowa
2013-10-29 0:43 ` David Miller
2013-10-29 9:37 ` David Laight
2013-10-29 12:40 ` Hannes Frederic Sowa
2013-10-29 13:09 ` Eric Dumazet
2013-10-29 13:11 ` Hannes Frederic Sowa
2013-10-29 19:58 ` David Miller
2013-11-01 21:28 ` Hannes Frederic Sowa
2013-11-05 17:02 ` Nicolas Dichtel
2013-11-05 17:12 ` David Laight
2013-11-05 21:11 ` Hannes Frederic Sowa
2013-11-06 9:23 ` David Laight
2013-11-06 12:03 ` Hannes Frederic Sowa
2013-11-05 20:57 ` Hannes Frederic Sowa
2013-11-06 8:11 ` Nicolas Dichtel
2013-11-09 0:54 ` [RFC PATCH net-next 1/2] ipv4: fix wildcard search with inet_confirm_addr() Nicolas Dichtel
2013-11-09 0:54 ` [RFC PATCH net-next 2/2] udp: add sk opt to allow sending pkt with src 0.0.0.0 Nicolas Dichtel
2013-11-09 14:46 ` Julian Anastasov
2013-11-12 8:59 ` Nicolas Dichtel [this message]
2013-11-11 5:18 ` David Miller
2013-11-14 13:05 ` Nicolas Dichtel
2013-11-14 19:57 ` David Miller
2013-11-18 9:15 ` Nicolas Dichtel
2013-11-14 14:31 ` Hannes Frederic Sowa
2013-11-14 20:00 ` David Miller
2013-10-29 19:44 ` [patch net-next] ipv6: allow userspace to create address with IFLA_F_TEMPORARY flag David Miller
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