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("");
+}