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Re: [Qemu-devel] [PATCH] linux-user: manage SOCK_PACKET socket type.
From: |
Laurent Vivier |
Subject: |
Re: [Qemu-devel] [PATCH] linux-user: manage SOCK_PACKET socket type. |
Date: |
Tue, 27 Oct 2015 12:54:58 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 |
Le 27/10/2015 12:50, Peter Maydell a écrit :
> On 27 October 2015 at 03:09, Laurent Vivier <address@hidden> wrote:
>> Le 26/10/2015 15:40, Peter Maydell a écrit :
>>> This confuses me. The packet(7) manpage suggests there are two flavours
>>> of packet socket:
>>> (1) legacy AF_INET + SOCK_PACKET
>>> (2) new style AF_PACKET + SOCK_RAW / SOCK_DGRAM
>>>
>>> but this comment suggests it's trying to handle AF_PACKET + SOCK_PACKET ?
>>
>> In fact, I've started not from the man page, but from a non working dhcp
>> client, originally with a m68k target and etch-m68k distro, and I've met
>> again this problem on a ppc target and jessie distro.
>
>> kernel 4.3.0-rc3, net/packet/af_packet.c:
>>
>> 2961
>> 2962 static int packet_bind_spkt(struct socket *sock, struct sockaddr
>> *uaddr,
>> 2963 int addr_len)
>> 2964 {
>> 2965 struct sock *sk = sock->sk;
>> 2966 char name[15];
>> 2967 struct net_device *dev;
>> 2968 int err = -ENODEV;
>> 2969
>> 2970 /*
>> 2971 * Check legality
>> 2972 */
>> 2973
>> 2974 if (addr_len != sizeof(struct sockaddr))
>> 2975 return -EINVAL;
>> 2976 strlcpy(name, uaddr->sa_data, sizeof(name));
>> 2977
>> 2978 dev = dev_get_by_name(sock_net(sk), name);
>> 2979 if (dev)
>> 2980 err = packet_do_bind(sk, dev, pkt_sk(sk)->num);
>> 2981 return err;
>> 2982 }
>> ...
>> 4246 static const struct proto_ops packet_ops_spkt = {
>> 4247 .family = PF_PACKET,
>> ...
>> 4250 .bind = packet_bind_spkt,
>> ...
>> 3022
>> 3023 static int packet_create(struct net *net, struct socket *sock,
>> int protocol,
>> 3024 int kern)
>> ...
>> 3045 if (sock->type == SOCK_PACKET)
>> 3046 sock->ops = &packet_ops_spkt;
>> ...
>
> Yes, but also:
> http://lxr.free-electrons.com/source/net/socket.c#L1109
>
> 1114 if (family == PF_INET && type == SOCK_PACKET) {
> 1115 static int warned;
> 1116 if (!warned) {
> 1117 warned = 1;
> 1118 pr_info("%s uses obsolete
> (PF_INET,SOCK_PACKET)\n",
> 1119 current->comm);
> 1120 }
> 1121 family = PF_PACKET;
> 1122 }
>
> So I think my conclusion is:
> * Original 2.0 kernels used PF_INET + SOCK_PACKET
> * When the non-legacy stuff was added and this compat warning
> came in, the (accidental?) result was that PF_PACKET + SOCK_PACKET
> gave a warning, PF_PACKET + SOCK_PACKET gave legacy behaviour
> without a warning, and PF_PACKET + SOCK_RAW/SOCK_DGRAM gave
> the new interface
> * Some userspace programs responded not by updating to the new
> non-legacy interface, but by moving to PF_PACKET + SOCK_PACKET
> which just suppresses the warning
>
> So we should special case both PF_INET + SOCK_PACKET and
> PF_PACKET + SOCK_PACKET (but not any other PF_* + SOCK_PACKET).
I'll try that too...
Laurent
- Re: [Qemu-devel] [PATCH] linux-user: manage SOCK_PACKET socket type., (continued)
- Re: [Qemu-devel] [PATCH] linux-user: manage SOCK_PACKET socket type., Peter Maydell, 2015/10/26
- Re: [Qemu-devel] [PATCH] linux-user: manage SOCK_PACKET socket type., Laurent Vivier, 2015/10/26
- Re: [Qemu-devel] [PATCH] linux-user: manage SOCK_PACKET socket type., Laurent Vivier, 2015/10/27
- Re: [Qemu-devel] [PATCH] linux-user: manage SOCK_PACKET socket type., Peter Maydell, 2015/10/27
- Re: [Qemu-devel] [PATCH] linux-user: manage SOCK_PACKET socket type., Peter Maydell, 2015/10/27
- Re: [Qemu-devel] [PATCH] linux-user: manage SOCK_PACKET socket type., Laurent Vivier, 2015/10/27
- Re: [Qemu-devel] [PATCH] linux-user: manage SOCK_PACKET socket type., Peter Maydell, 2015/10/27
- Re: [Qemu-devel] [PATCH] linux-user: manage SOCK_PACKET socket type., Laurent Vivier, 2015/10/27
- Re: [Qemu-devel] [PATCH] linux-user: manage SOCK_PACKET socket type., Laurent Vivier, 2015/10/27
- Re: [Qemu-devel] [PATCH] linux-user: manage SOCK_PACKET socket type., Peter Maydell, 2015/10/27
- Re: [Qemu-devel] [PATCH] linux-user: manage SOCK_PACKET socket type.,
Laurent Vivier <=