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-rw-r--r--net/rxrpc/ar-skbuff.c118
1 files changed, 118 insertions, 0 deletions
diff --git a/net/rxrpc/ar-skbuff.c b/net/rxrpc/ar-skbuff.c
new file mode 100644
index 000000000000..d73f6fc76011
--- /dev/null
+++ b/net/rxrpc/ar-skbuff.c
@@ -0,0 +1,118 @@
+/* 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)
+ schedule_work(&call->processor);
+ 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("");
+}

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