[AFS]: Add support for the CB.GetCapabilities operation.

Add support for the CB.GetCapabilities operation with which the fileserver can
ask the client for the following information:

 (1) The list of network interfaces it has available as IPv4 address + netmask
     plus the MTUs.

 (2) The client's UUID.

 (3) The extended capabilities of the client, for which the only current one
     is unified error mapping (abort code interpretation).

To support this, the patch adds the following routines to AFS:

 (1) A function to iterate through all the network interfaces using RTNETLINK
     to extract IPv4 addresses and MTUs.

 (2) A function to iterate through all the network interfaces using RTNETLINK
     to pull out the MAC address of the lowest index interface to use in UUID
     construction.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 39 insertions, 0 deletions

diff --git a/fs/afs/rxrpc.c b/fs/afs/rxrpc.c
index e86c527..e7b0473 100644
--- a/fs/afs/rxrpc.c
+++ b/fs/afs/rxrpc.c
@@ -714,6 +714,45 @@ void afs_send_empty_reply(struct afs_call *call)
 }
 
 /*
+ * send a simple reply
+ */
+void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
+{
+	struct msghdr msg;
+	struct iovec iov[1];
+
+	_enter("");
+
+	iov[0].iov_base		= (void *) buf;
+	iov[0].iov_len		= len;
+	msg.msg_name		= NULL;
+	msg.msg_namelen		= 0;
+	msg.msg_iov		= iov;
+	msg.msg_iovlen		= 1;
+	msg.msg_control		= NULL;
+	msg.msg_controllen	= 0;
+	msg.msg_flags		= 0;
+
+	call->state = AFS_CALL_AWAIT_ACK;
+	switch (rxrpc_kernel_send_data(call->rxcall, &msg, len)) {
+	case 0:
+		_leave(" [replied]");
+		return;
+
+	case -ENOMEM:
+		_debug("oom");
+		rxrpc_kernel_abort_call(call->rxcall, RX_USER_ABORT);
+	default:
+		rxrpc_kernel_end_call(call->rxcall);
+		call->rxcall = NULL;
+		call->type->destructor(call);
+		afs_free_call(call);
+		_leave(" [error]");
+		return;
+	}
+}
+
+/*
  * extract a piece of data from the received data socket buffers
  */
 int afs_extract_data(struct afs_call *call, struct sk_buff *skb,