139 lines
3.7 KiB
C
139 lines
3.7 KiB
C
/* ar-skbuff.c: socket buffer destruction handling
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*
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* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/net.h>
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#include <linux/skbuff.h>
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#include <net/sock.h>
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#include <net/af_rxrpc.h>
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#include "ar-internal.h"
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/*
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* set up for the ACK at the end of the receive phase when we discard the final
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* receive phase data packet
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* - called with softirqs disabled
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*/
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static void rxrpc_request_final_ACK(struct rxrpc_call *call)
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{
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/* the call may be aborted before we have a chance to ACK it */
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write_lock(&call->state_lock);
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switch (call->state) {
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case RXRPC_CALL_CLIENT_RECV_REPLY:
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call->state = RXRPC_CALL_CLIENT_FINAL_ACK;
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_debug("request final ACK");
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/* get an extra ref on the call for the final-ACK generator to
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* release */
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rxrpc_get_call(call);
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set_bit(RXRPC_CALL_EV_ACK_FINAL, &call->events);
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if (try_to_del_timer_sync(&call->ack_timer) >= 0)
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rxrpc_queue_call(call);
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break;
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case RXRPC_CALL_SERVER_RECV_REQUEST:
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call->state = RXRPC_CALL_SERVER_ACK_REQUEST;
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default:
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break;
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}
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write_unlock(&call->state_lock);
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}
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/*
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* drop the bottom ACK off of the call ACK window and advance the window
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*/
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static void rxrpc_hard_ACK_data(struct rxrpc_call *call,
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struct rxrpc_skb_priv *sp)
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{
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int loop;
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u32 seq;
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spin_lock_bh(&call->lock);
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_debug("hard ACK #%u", sp->hdr.seq);
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for (loop = 0; loop < RXRPC_ACKR_WINDOW_ASZ; loop++) {
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call->ackr_window[loop] >>= 1;
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call->ackr_window[loop] |=
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call->ackr_window[loop + 1] << (BITS_PER_LONG - 1);
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}
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seq = sp->hdr.seq;
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ASSERTCMP(seq, ==, call->rx_data_eaten + 1);
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call->rx_data_eaten = seq;
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if (call->ackr_win_top < UINT_MAX)
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call->ackr_win_top++;
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ASSERTIFCMP(call->state <= RXRPC_CALL_COMPLETE,
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call->rx_data_post, >=, call->rx_data_recv);
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ASSERTIFCMP(call->state <= RXRPC_CALL_COMPLETE,
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call->rx_data_recv, >=, call->rx_data_eaten);
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if (sp->hdr.flags & RXRPC_LAST_PACKET) {
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rxrpc_request_final_ACK(call);
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} else if (atomic_dec_and_test(&call->ackr_not_idle) &&
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test_and_clear_bit(RXRPC_CALL_TX_SOFT_ACK, &call->flags)) {
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/* We previously soft-ACK'd some received packets that have now
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* been consumed, so send a hard-ACK if no more packets are
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* immediately forthcoming to allow the transmitter to free up
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* its Tx bufferage.
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*/
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_debug("send Rx idle ACK");
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__rxrpc_propose_ACK(call, RXRPC_ACK_IDLE, sp->hdr.serial,
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false);
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}
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spin_unlock_bh(&call->lock);
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}
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/*
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* destroy a packet that has an RxRPC control buffer
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* - advance the hard-ACK state of the parent call (done here in case something
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* in the kernel bypasses recvmsg() and steals the packet directly off of the
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* socket receive queue)
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*/
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void rxrpc_packet_destructor(struct sk_buff *skb)
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{
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struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
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struct rxrpc_call *call = sp->call;
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_enter("%p{%p}", skb, call);
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if (call) {
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/* send the final ACK on a client call */
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if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA)
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rxrpc_hard_ACK_data(call, sp);
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rxrpc_put_call(call);
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sp->call = NULL;
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}
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if (skb->sk)
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sock_rfree(skb);
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_leave("");
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}
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/**
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* rxrpc_kernel_free_skb - Free an RxRPC socket buffer
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* @skb: The socket buffer to be freed
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*
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* Let RxRPC free its own socket buffer, permitting it to maintain debug
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* accounting.
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*/
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void rxrpc_kernel_free_skb(struct sk_buff *skb)
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{
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rxrpc_free_skb(skb);
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}
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EXPORT_SYMBOL(rxrpc_kernel_free_skb);
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