Phonet: cleanup pipe enable socket option

The current code works like this:

  int garbage, status;
  socklen_t len = sizeof(status);

  /* enable pipe */
  setsockopt(fd, SOL_PNPIPE, PNPIPE_ENABLE, &garbage, sizeof(garbage));
  /* disable pipe */
  setsockopt(fd, SOL_PNPIPE, PNPIPE_DISABLE, &garbage, sizeof(garbage));
  /* get status */
  getsockopt(fd, SOL_PNPIPE, PNPIPE_INQ, &status, &len);

...which does not follow the usual socket option pattern. This patch
merges all three "options" into a single gettable&settable option,
before Linux 2.6.37 gets out:

  int status;
  socklen_t len = sizeof(status);

  /* enable pipe */
  status = 1;
  setsockopt(fd, SOL_PNPIPE, PNPIPE_ENABLE, &status, sizeof(status));
  /* disable pipe */
  status = 0;
  setsockopt(fd, SOL_PNPIPE, PNPIPE_ENABLE, &status, sizeof(status));
  /* get status */
  getsockopt(fd, SOL_PNPIPE, PNPIPE_ENABLE, &status, &len);

This also fixes the error code from EFAULT to ENOTCONN.

Signed-off-by: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
Cc: Kumar Sanghvi <kumar.sanghvi@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/phonet.txt

@@ -213,12 +213,9 @@ The implementation adds socket options at SOL_PNPIPE level:
 	It then updates the pipe state associated with the sequenced socket to
 	be PIPE_DISABLED.
 
-  PNPIPE_ENABLE
-	It follows the same sequence as above for enabling a pipe by sending
-	PNS_PEP_ENABLE_REQ initially and then sending PNS_PEP_ENABLED_IND after
-	getting responses from sequenced socket and remote-pep.
-	It will also update the pipe state associated with the sequenced socket
-	to PIPE_ENABLED.
+  PNPIPE_ENABLE accepts one integer value (int). If set to zero, the pipe
+    is disabled. If the value is non-zero, the pipe is enabled. If the pipe
+    is not (yet) connected, ENOTCONN is error is returned.
 
    PNPIPE_DESTROY
 	This will send out PNS_PEP_DISCONNECT_REQ on the sequenced socket and
@@ -226,12 +223,6 @@ The implementation adds socket options at SOL_PNPIPE level:
 	It will also update the pipe state associated with the sequenced socket
 	to PIPE_IDLE
 
-   PNPIPE_INQ
-	This getsocktopt allows the user-space running on the sequenced socket
-	to examine the pipe state associated with that socket ie. whether the
-	pipe is created (PIPE_DISABLED) or enabled (PIPE_ENABLED) or disabled
-	(PIPE_DISABLED) or no pipe exists (PIPE_IDLE).
-
 After a pipe has been created and enabled successfully, the Pipe data can be
 exchanged between the host-pep and remote-pep (modem).
 

include/linux/phonet.h

@@ -38,9 +38,8 @@
 #define PNPIPE_IFINDEX		2
 #define PNPIPE_CREATE           3
 #define PNPIPE_ENABLE           4
-#define PNPIPE_DISABLE          5
+/* unused slot */
 #define PNPIPE_DESTROY          6
-#define PNPIPE_INQ              7
 
 #define PNADDR_ANY		0
 #define PNADDR_BROADCAST	0xFC

net/phonet/pep.c

@@ -327,29 +327,20 @@ static int pipe_handler_send_ind(struct sock *sk, u16 dobj, u8 utid,
 	return pn_skb_send(sk, skb, &spn);
 }
 
-static int pipe_handler_enable_pipe(struct sock *sk, int cmd)
+static int pipe_handler_enable_pipe(struct sock *sk, int enable)
 {
-	int ret;
 	struct pep_sock *pn = pep_sk(sk);
+	int utid, req;
 
-	switch (cmd) {
-	case PNPIPE_ENABLE:
-		ret = pipe_handler_send_req(sk, pn->pn_sk.sobject,
-				PNS_PIPE_ENABLE_UTID, PNS_PEP_ENABLE_REQ,
-				pn->pipe_handle, GFP_ATOMIC);
-		break;
-
-	case PNPIPE_DISABLE:
-		ret = pipe_handler_send_req(sk, pn->pn_sk.sobject,
-				PNS_PIPE_DISABLE_UTID, PNS_PEP_DISABLE_REQ,
-				pn->pipe_handle, GFP_ATOMIC);
-		break;
-
-	default:
-		ret = -EINVAL;
+	if (enable) {
+		utid = PNS_PIPE_ENABLE_UTID;
+		req = PNS_PEP_ENABLE_REQ;
+	} else {
+		utid = PNS_PIPE_DISABLE_UTID;
+		req = PNS_PEP_DISABLE_REQ;
 	}
-
-	return ret;
+	return pipe_handler_send_req(sk, pn->pn_sk.sobject, utid, req,
+			pn->pipe_handle, GFP_ATOMIC);
 }
 
 static int pipe_handler_create_pipe(struct sock *sk, int pipe_handle, int cmd)
@@ -1187,23 +1178,6 @@ static int pep_setsockopt(struct sock *sk, int level, int optname,
 			break;
 		}
 
-	case PNPIPE_ENABLE:
-		if (pn->pipe_state != PIPE_DISABLED) {
-			err = -EFAULT;
-			break;
-		}
-		err = pipe_handler_enable_pipe(sk, PNPIPE_ENABLE);
-		break;
-
-	case PNPIPE_DISABLE:
-		if (pn->pipe_state != PIPE_ENABLED) {
-			err = -EFAULT;
-			break;
-		}
-
-		err = pipe_handler_enable_pipe(sk, PNPIPE_DISABLE);
-		break;
-
 	case PNPIPE_DESTROY:
 		if (pn->pipe_state < PIPE_DISABLED) {
 			err = -EFAULT;
@@ -1239,6 +1213,17 @@ static int pep_setsockopt(struct sock *sk, int level, int optname,
 			err = 0;
 		}
 		goto out_norel;
+
+#ifdef CONFIG_PHONET_PIPECTRLR
+	case PNPIPE_ENABLE:
+		if (pn->pipe_state <= PIPE_IDLE) {
+			err = -ENOTCONN;
+			break;
+		}
+		err = pipe_handler_enable_pipe(sk, val);
+		break;
+#endif
+
 	default:
 		err = -ENOPROTOOPT;
 	}
@@ -1264,15 +1249,18 @@ static int pep_getsockopt(struct sock *sk, int level, int optname,
 		val = pn->ifindex ? PNPIPE_ENCAP_IP : PNPIPE_ENCAP_NONE;
 		break;
 
-#ifdef CONFIG_PHONET_PIPECTRLR
-	case PNPIPE_INQ:
-		val = pn->pipe_state;
-		break;
-#endif
-
 	case PNPIPE_IFINDEX:
 		val = pn->ifindex;
 		break;
+
+#ifdef CONFIG_PHONET_PIPECTRLR
+	case PNPIPE_ENABLE:
+		if (pn->pipe_state <= PIPE_IDLE)
+			return -ENOTCONN;
+		val = pn->pipe_state != PIPE_DISABLED;
+		break;
+#endif
+
 	default:
 		return -ENOPROTOOPT;
 	}