1 files changed, 132 insertions, 0 deletions
diff --git a/net/rxrpc/ar-skbuff.c b/net/rxrpc/ar-skbuff.c
new file mode 100644
index 00000000000..de755e04d29
--- /dev/null
+++ b/net/rxrpc/ar-skbuff.c
@@ -0,0 +1,132 @@
+/* ar-skbuff.c: socket buffer destruction handling
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/net.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <net/af_rxrpc.h>
+#include "ar-internal.h"
+
+/*
+ * set up for the ACK at the end of the receive phase when we discard the final
+ * receive phase data packet
+ * - called with softirqs disabled
+ */
+static void rxrpc_request_final_ACK(struct rxrpc_call *call)
+{
+	/* the call may be aborted before we have a chance to ACK it */
+	write_lock(&call->state_lock);
+
+	switch (call->state) {
+	case RXRPC_CALL_CLIENT_RECV_REPLY:
+		call->state = RXRPC_CALL_CLIENT_FINAL_ACK;
+		_debug("request final ACK");
+
+		/* get an extra ref on the call for the final-ACK generator to
+		 * release */
+		rxrpc_get_call(call);
+		set_bit(RXRPC_CALL_ACK_FINAL, &call->events);
+		if (try_to_del_timer_sync(&call->ack_timer) >= 0)
+			rxrpc_queue_call(call);
+		break;
+
+	case RXRPC_CALL_SERVER_RECV_REQUEST:
+		call->state = RXRPC_CALL_SERVER_ACK_REQUEST;
+	default:
+		break;
+	}
+
+	write_unlock(&call->state_lock);
+}
+
+/*
+ * drop the bottom ACK off of the call ACK window and advance the window
+ */
+static void rxrpc_hard_ACK_data(struct rxrpc_call *call,
+				struct rxrpc_skb_priv *sp)
+{
+	int loop;
+	u32 seq;
+
+	spin_lock_bh(&call->lock);
+
+	_debug("hard ACK #%u", ntohl(sp->hdr.seq));
+
+	for (loop = 0; loop < RXRPC_ACKR_WINDOW_ASZ; loop++) {
+		call->ackr_window[loop] >>= 1;
+		call->ackr_window[loop] |=
+			call->ackr_window[loop + 1] << (BITS_PER_LONG - 1);
+	}
+
+	seq = ntohl(sp->hdr.seq);
+	ASSERTCMP(seq, ==, call->rx_data_eaten + 1);
+	call->rx_data_eaten = seq;
+
+	if (call->ackr_win_top < UINT_MAX)
+		call->ackr_win_top++;
+
+	ASSERTIFCMP(call->state <= RXRPC_CALL_COMPLETE,
+		    call->rx_data_post, >=, call->rx_data_recv);
+	ASSERTIFCMP(call->state <= RXRPC_CALL_COMPLETE,
+		    call->rx_data_recv, >=, call->rx_data_eaten);
+
+	if (sp->hdr.flags & RXRPC_LAST_PACKET) {
+		rxrpc_request_final_ACK(call);
+	} else if (atomic_dec_and_test(&call->ackr_not_idle) &&
+		   test_and_clear_bit(RXRPC_CALL_TX_SOFT_ACK, &call->flags)) {
+		_debug("send Rx idle ACK");
+		__rxrpc_propose_ACK(call, RXRPC_ACK_IDLE, sp->hdr.serial,
+				    true);
+	}
+
+	spin_unlock_bh(&call->lock);
+}
+
+/*
+ * destroy a packet that has an RxRPC control buffer
+ * - advance the hard-ACK state of the parent call (done here in case something
+ *   in the kernel bypasses recvmsg() and steals the packet directly off of the
+ *   socket receive queue)
+ */
+void rxrpc_packet_destructor(struct sk_buff *skb)
+{
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	struct rxrpc_call *call = sp->call;
+
+	_enter("%p{%p}", skb, call);
+
+	if (call) {
+		/* send the final ACK on a client call */
+		if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA)
+			rxrpc_hard_ACK_data(call, sp);
+		rxrpc_put_call(call);
+		sp->call = NULL;
+	}
+
+	if (skb->sk)
+		sock_rfree(skb);
+	_leave("");
+}
+
+/**
+ * rxrpc_kernel_free_skb - Free an RxRPC socket buffer
+ * @skb: The socket buffer to be freed
+ *
+ * Let RxRPC free its own socket buffer, permitting it to maintain debug
+ * accounting.
+ */
+void rxrpc_kernel_free_skb(struct sk_buff *skb)
+{
+	rxrpc_free_skb(skb);
+}
+
+EXPORT_SYMBOL(rxrpc_kernel_free_skb);