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Subject: Re: [PATCH] ieee802154: add rx LQI from userspace
To:     =?UTF-8?B?Q2zDqW1lbnQgUMOpcm9u?= <peron.clem@gmail.com>,
        Romuald Cari <romuald.cari@devialet.com>,
        linux-wpan@vger.kernel.org
Cc:     Alexander Aring <alex.aring@gmail.com>,
        Stefan Schmidt <stefan@osg.samsung.com>,
        "David S . Miller" <davem@davemloft.net>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        =?UTF-8?Q?Cl=c3=a9ment_Peron?= <clement.peron@devialet.com>
References: <20180607140802.22666-1-peron.clem@gmail.com>
From:   Stefan Schmidt <stefan@datenfreihafen.org>
Message-ID: <35c6ef3e-7f7b-2a2d-d73b-201efbc4594c@datenfreihafen.org>
Date:   Mon, 6 Aug 2018 11:07:39 +0200
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Hello.

On 06/07/2018 04:08 PM, Clément Péron wrote:
> From: Romuald CARI <romuald.cari@devialet.com>
> 
> The Link Quality Indication data exposed by drivers could not be accessed from
> userspace. Since this data is per-datagram received, it makes sense to make it
> available to userspace application through the ancillary data mechanism in
> recvmsg rather than through ioctls. This can be activated using the socket
> option WPAN_WANTLQI under SOL_IEEE802154 protocol.
> 
> This LQI data is available in the ancillary data buffer under the SOL_IEEE802154
> level as the type WPAN_LQI. The value is an unsigned byte indicating the link
> quality with values ranging 0-255.
> 
> Signed-off-by: Romuald Cari <romuald.cari@devialet.com>
> Signed-off-by: Clément Peron <clement.peron@devialet.com>
> ---
>  include/net/af_ieee802154.h |  1 +
>  net/ieee802154/socket.c     | 17 +++++++++++++++++
>  2 files changed, 18 insertions(+)
> 
> diff --git a/include/net/af_ieee802154.h b/include/net/af_ieee802154.h
> index a5563d27a3eb..8003a9f6eb43 100644
> --- a/include/net/af_ieee802154.h
> +++ b/include/net/af_ieee802154.h
> @@ -56,6 +56,7 @@ struct sockaddr_ieee802154 {
>  #define WPAN_WANTACK		0
>  #define WPAN_SECURITY		1
>  #define WPAN_SECURITY_LEVEL	2
> +#define WPAN_WANTLQI		3
>  
>  #define WPAN_SECURITY_DEFAULT	0
>  #define WPAN_SECURITY_OFF	1
> diff --git a/net/ieee802154/socket.c b/net/ieee802154/socket.c
> index a60658c85a9a..bc6b912603f1 100644
> --- a/net/ieee802154/socket.c
> +++ b/net/ieee802154/socket.c
> @@ -25,6 +25,7 @@
>  #include <linux/termios.h>	/* For TIOCOUTQ/INQ */
>  #include <linux/list.h>
>  #include <linux/slab.h>
> +#include <linux/socket.h>
>  #include <net/datalink.h>
>  #include <net/psnap.h>
>  #include <net/sock.h>
> @@ -452,6 +453,7 @@ struct dgram_sock {
>  	unsigned int bound:1;
>  	unsigned int connected:1;
>  	unsigned int want_ack:1;
> +	unsigned int want_lqi:1;
>  	unsigned int secen:1;
>  	unsigned int secen_override:1;
>  	unsigned int seclevel:3;
> @@ -486,6 +488,7 @@ static int dgram_init(struct sock *sk)
>  	struct dgram_sock *ro = dgram_sk(sk);
>  
>  	ro->want_ack = 1;
> +	ro->want_lqi = 0;
>  	return 0;
>  }
>  
> @@ -713,6 +716,7 @@ static int dgram_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
>  	size_t copied = 0;
>  	int err = -EOPNOTSUPP;
>  	struct sk_buff *skb;
> +	struct dgram_sock *ro = dgram_sk(sk);
>  	DECLARE_SOCKADDR(struct sockaddr_ieee802154 *, saddr, msg->msg_name);
>  
>  	skb = skb_recv_datagram(sk, flags, noblock, &err);
> @@ -744,6 +748,13 @@ static int dgram_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
>  		*addr_len = sizeof(*saddr);
>  	}
>  
> +	if (ro->want_lqi) {
> +		err = put_cmsg(msg, SOL_IEEE802154, WPAN_WANTLQI,
> +			       sizeof(uint8_t), &(mac_cb(skb)->lqi));
> +		if (err)
> +			goto done;
> +	}
> +
>  	if (flags & MSG_TRUNC)
>  		copied = skb->len;
>  done:
> @@ -847,6 +858,9 @@ static int dgram_getsockopt(struct sock *sk, int level, int optname,
>  	case WPAN_WANTACK:
>  		val = ro->want_ack;
>  		break;
> +	case WPAN_WANTLQI:
> +		val = ro->want_lqi;
> +		break;
>  	case WPAN_SECURITY:
>  		if (!ro->secen_override)
>  			val = WPAN_SECURITY_DEFAULT;
> @@ -892,6 +906,9 @@ static int dgram_setsockopt(struct sock *sk, int level, int optname,
>  	case WPAN_WANTACK:
>  		ro->want_ack = !!val;
>  		break;
> +	case WPAN_WANTLQI:
> +		ro->want_lqi = !!val;
> +		break;
>  	case WPAN_SECURITY:
>  		if (!ns_capable(net->user_ns, CAP_NET_ADMIN) &&
>  		    !ns_capable(net->user_ns, CAP_NET_RAW)) {
> 

This patch has been applied to the wpan-next tree and will be
part of the next pull request to net-next. Thanks!

regards
Stefan Schmidt