Re: [PATCH v2] Phonet: set the pipe handle using setsockopt

["Rémi Denis-Courmont" <remi@remlab.net>]

On Thu, 10 Nov 2011 15:20:22 +0530, Hemant Vilas RAMDASI
<hemant.ramdasi@stericsson.com> wrote:
> From: Dinesh Kumar Sharma <dinesh.sharma@stericsson.com>
> 
> This provides flexibility to set the pipe handle
> using setsockopt and enable the same.
> 
> Signed-off-by: Hemant Ramdasi <hemant.ramdasi@stericsson.com>
> Signed-off-by: Dinesh Kumar Sharma <dinesh.sharma@stericsson.com>
> ---
>  include/linux/phonet.h |    2 +
>  net/phonet/pep.c       |   90
>  ++++++++++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 90 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/phonet.h b/include/linux/phonet.h
> index 6fb1384..491caec 100644
> --- a/include/linux/phonet.h
> +++ b/include/linux/phonet.h
> @@ -37,6 +37,8 @@
>  #define PNPIPE_ENCAP		1
>  #define PNPIPE_IFINDEX		2
>  #define PNPIPE_HANDLE		3
> +#define PNPIPE_ENABLE		4
> +#define PNPIPE_INITSTATE	5
>  
>  #define PNADDR_ANY		0
>  #define PNADDR_BROADCAST	0xFC
> diff --git a/net/phonet/pep.c b/net/phonet/pep.c
> index f17fd84..f8057a1 100644
> --- a/net/phonet/pep.c
> +++ b/net/phonet/pep.c
> @@ -167,6 +167,12 @@ static int pipe_handler_send_created_ind(struct
sock
> *sk)
>  				data, 4, GFP_ATOMIC);
>  }
>  
> +static int pipe_handler_send_enabled_ind(struct sock *sk)
> +{
> +	return pep_indicate(sk, PNS_PIPE_ENABLED_IND, 0 /* sub-blocks */,
> +				NULL, 0, GFP_ATOMIC);
> +}
> +
>  static int pep_accept_conn(struct sock *sk, struct sk_buff *skb)
>  {
>  	static const u8 data[20] = {
> @@ -533,6 +539,17 @@ static int pep_connresp_rcv(struct sock *sk, struct
> sk_buff *skb)
>  	return pipe_handler_send_created_ind(sk);
>  }
>  
> +static int pep_enableresp_rcv(struct sock *sk, struct sk_buff *skb)
> +{
> +	struct pnpipehdr *hdr = pnp_hdr(skb);
> +
> +	if (hdr->error_code != PN_PIPE_NO_ERROR)
> +		return -ECONNREFUSED;
> +
> +	return pipe_handler_send_enabled_ind(sk);
> +}
> +
> +
>  /* Queue an skb to an actively connected sock.
>   * Socket lock must be held. */
>  static int pipe_handler_do_rcv(struct sock *sk, struct sk_buff *skb)
> @@ -578,6 +595,28 @@ static int pipe_handler_do_rcv(struct sock *sk,
> struct sk_buff *skb)
>  			sk->sk_state = TCP_CLOSE_WAIT;
>  			break;
>  		}
> +		if (pn->init_enable == PN_PIPE_DISABLE)
> +			sk->sk_state = TCP_SYN_RECV;
> +		else {
> +			sk->sk_state = TCP_ESTABLISHED;
> +
> +			if (!pn_flow_safe(pn->tx_fc)) {
> +				atomic_set(&pn->tx_credits, 1);
> +				sk->sk_write_space(sk);
> +			}
> +			pipe_grant_credits(sk, GFP_ATOMIC);
> +
> +		}

I'd rather not duplicate this code as far as possible.

> +		break;
> +
> +	case PNS_PEP_ENABLE_RESP:
> +		if (sk->sk_state != TCP_SYN_SENT)
> +			break;
> +
> +		if (pep_enableresp_rcv(sk, skb)) {
> +			sk->sk_state = TCP_CLOSE_WAIT;
> +			break;
> +		}
>  
>  		sk->sk_state = TCP_ESTABLISHED;
>  		if (!pn_flow_safe(pn->tx_fc)) {
> @@ -863,9 +902,26 @@ static int pep_sock_connect(struct sock *sk, struct
> sockaddr *addr, int len)
>  	int err;
>  	u8 data[4] = { 0 /* sub-blocks */, PAD, PAD, PAD };
>  
> -	pn->pipe_handle = 1; /* anything but INVALID_HANDLE */
> +	if (pn->pipe_handle == PN_PIPE_INVALID_HANDLE)
> +		pn->pipe_handle = 1; /* anything but INVALID_HANDLE */
> +
>  	err = pipe_handler_request(sk, PNS_PEP_CONNECT_REQ,
> -					PN_PIPE_ENABLE, data, 4);
> +				pn->init_enable, data, 4);
> +	if (err)
> +		return err;
> +
> +	sk->sk_state = TCP_SYN_SENT;
> +
> +	return 0;
> +}
> +
> +static int pep_sock_enable(struct sock *sk, struct sockaddr *addr, int
> len)
> +{
> +	struct pep_sock *pn = pep_sk(sk);
> +	int err;
> +
> +	err = pipe_handler_request(sk, PNS_PEP_ENABLE_REQ, PAD,
> +				NULL, 0);
>  	if (err) {
>  		pn->pipe_handle = PN_PIPE_INVALID_HANDLE;
>  		return err;

I doubt that a pipe in connected state with no handle is going to work.

> @@ -959,6 +1015,29 @@ static int pep_setsockopt(struct sock *sk, int
> level, int optname,
>  		}
>  		goto out_norel;
>  
> +	case PNPIPE_HANDLE:
> +		if ((val >= 0) && (val < PN_PIPE_INVALID_HANDLE))
> +			pn->pipe_handle = val;
> +		else
> +			err = -EINVAL;
> +		break;

This should only be settable before connect(), I guess.

> +
> +	case PNPIPE_ENABLE:
> +		if (sk->sk_state == TCP_SYN_SENT)
> +			err = -EBUSY;

This statement has no effects. You probably forgot something.

> +		if (sk->sk_state == TCP_ESTABLISHED)
> +			err = -EISCONN;
> +		else
> +			err = pep_sock_enable(sk, NULL, 0);
> +		break;

This still does not follow the setter/getter level-trigger semantics of
(s|g)etsockopt().

> +
> +	case PNPIPE_INITSTATE:
> +		if ((val == PN_PIPE_DISABLE) || (val == PN_PIPE_ENABLE))
> +			pn->init_enable = val;
> +		else
> +			err = -EINVAL;

IMHO, PNPIPE_INIT_ENABLE and boolean values would be simpler. I don't
really fancy exposing protocol-internal values to user space unless really
needed.

> +		break;
> +
>  	default:
>  		err = -ENOPROTOOPT;
>  	}
> @@ -994,6 +1073,13 @@ static int pep_getsockopt(struct sock *sk, int
> level, int optname,
>  			return -EINVAL;
>  		break;
>  
> +	case PNPIPE_ENABLE:
> +		if (sk->sk_state != TCP_ESTABLISHED)
> +			return -EINVAL;
> +		else
> +			val = 1;
> +		break;

This does not look correct.

> +

PNPIPE_INITSTATE is missing.

>  	default:
>  		return -ENOPROTOOPT;
>  	}

-- 
Rémi Denis-Courmont
http://www.remlab.net/