367 lines
9.0 KiB
C
367 lines
9.0 KiB
C
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/* RxRPC recvmsg() implementation
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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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#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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* removal a call's user ID from the socket tree to make the user ID available
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* again and so that it won't be seen again in association with that call
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*/
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static void rxrpc_remove_user_ID(struct rxrpc_sock *rx, struct rxrpc_call *call)
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{
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_debug("RELEASE CALL %d", call->debug_id);
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if (test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
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write_lock_bh(&rx->call_lock);
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rb_erase(&call->sock_node, &call->socket->calls);
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clear_bit(RXRPC_CALL_HAS_USERID, &call->flags);
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write_unlock_bh(&rx->call_lock);
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}
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read_lock_bh(&call->state_lock);
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if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
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!test_and_set_bit(RXRPC_CALL_RELEASE, &call->events))
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schedule_work(&call->processor);
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read_unlock_bh(&call->state_lock);
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}
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/*
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* receive a message from an RxRPC socket
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* - we need to be careful about two or more threads calling recvmsg
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* simultaneously
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*/
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int rxrpc_recvmsg(struct kiocb *iocb, struct socket *sock,
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struct msghdr *msg, size_t len, int flags)
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{
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struct rxrpc_skb_priv *sp;
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struct rxrpc_call *call = NULL, *continue_call = NULL;
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struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
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struct sk_buff *skb;
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long timeo;
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int copy, ret, ullen, offset, copied = 0;
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u32 abort_code;
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DEFINE_WAIT(wait);
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_enter(",,,%zu,%d", len, flags);
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if (flags & (MSG_OOB | MSG_TRUNC))
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return -EOPNOTSUPP;
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ullen = msg->msg_flags & MSG_CMSG_COMPAT ? 4 : sizeof(unsigned long);
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timeo = sock_rcvtimeo(&rx->sk, flags & MSG_DONTWAIT);
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msg->msg_flags |= MSG_MORE;
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lock_sock(&rx->sk);
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for (;;) {
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/* return immediately if a client socket has no outstanding
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* calls */
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if (RB_EMPTY_ROOT(&rx->calls)) {
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if (copied)
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goto out;
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if (rx->sk.sk_state != RXRPC_SERVER_LISTENING) {
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release_sock(&rx->sk);
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if (continue_call)
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rxrpc_put_call(continue_call);
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return -ENODATA;
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}
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}
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/* get the next message on the Rx queue */
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skb = skb_peek(&rx->sk.sk_receive_queue);
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if (!skb) {
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/* nothing remains on the queue */
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if (copied &&
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(msg->msg_flags & MSG_PEEK || timeo == 0))
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goto out;
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/* wait for a message to turn up */
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release_sock(&rx->sk);
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prepare_to_wait_exclusive(rx->sk.sk_sleep, &wait,
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TASK_INTERRUPTIBLE);
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ret = sock_error(&rx->sk);
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if (ret)
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goto wait_error;
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if (skb_queue_empty(&rx->sk.sk_receive_queue)) {
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if (signal_pending(current))
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goto wait_interrupted;
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timeo = schedule_timeout(timeo);
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}
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finish_wait(rx->sk.sk_sleep, &wait);
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lock_sock(&rx->sk);
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continue;
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}
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peek_next_packet:
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sp = rxrpc_skb(skb);
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call = sp->call;
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ASSERT(call != NULL);
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_debug("next pkt %s", rxrpc_pkts[sp->hdr.type]);
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/* make sure we wait for the state to be updated in this call */
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spin_lock_bh(&call->lock);
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spin_unlock_bh(&call->lock);
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if (test_bit(RXRPC_CALL_RELEASED, &call->flags)) {
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_debug("packet from released call");
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if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
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BUG();
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rxrpc_free_skb(skb);
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continue;
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}
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/* determine whether to continue last data receive */
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if (continue_call) {
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_debug("maybe cont");
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if (call != continue_call ||
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skb->mark != RXRPC_SKB_MARK_DATA) {
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release_sock(&rx->sk);
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rxrpc_put_call(continue_call);
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_leave(" = %d [noncont]", copied);
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return copied;
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}
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}
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rxrpc_get_call(call);
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/* copy the peer address and timestamp */
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if (!continue_call) {
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if (msg->msg_name && msg->msg_namelen > 0)
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memcpy(&msg->msg_name, &call->conn->trans->peer->srx,
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sizeof(call->conn->trans->peer->srx));
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sock_recv_timestamp(msg, &rx->sk, skb);
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}
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/* receive the message */
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if (skb->mark != RXRPC_SKB_MARK_DATA)
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goto receive_non_data_message;
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_debug("recvmsg DATA #%u { %d, %d }",
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ntohl(sp->hdr.seq), skb->len, sp->offset);
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if (!continue_call) {
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/* only set the control data once per recvmsg() */
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ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
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ullen, &call->user_call_ID);
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if (ret < 0)
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goto copy_error;
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ASSERT(test_bit(RXRPC_CALL_HAS_USERID, &call->flags));
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}
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ASSERTCMP(ntohl(sp->hdr.seq), >=, call->rx_data_recv);
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ASSERTCMP(ntohl(sp->hdr.seq), <=, call->rx_data_recv + 1);
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call->rx_data_recv = ntohl(sp->hdr.seq);
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ASSERTCMP(ntohl(sp->hdr.seq), >, call->rx_data_eaten);
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offset = sp->offset;
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copy = skb->len - offset;
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if (copy > len - copied)
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copy = len - copied;
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if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
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ret = skb_copy_datagram_iovec(skb, offset,
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msg->msg_iov, copy);
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} else {
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ret = skb_copy_and_csum_datagram_iovec(skb, offset,
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msg->msg_iov);
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if (ret == -EINVAL)
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goto csum_copy_error;
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}
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if (ret < 0)
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goto copy_error;
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/* handle piecemeal consumption of data packets */
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_debug("copied %d+%d", copy, copied);
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offset += copy;
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copied += copy;
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if (!(flags & MSG_PEEK))
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sp->offset = offset;
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if (sp->offset < skb->len) {
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_debug("buffer full");
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ASSERTCMP(copied, ==, len);
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break;
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}
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/* we transferred the whole data packet */
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if (sp->hdr.flags & RXRPC_LAST_PACKET) {
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_debug("last");
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if (call->conn->out_clientflag) {
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/* last byte of reply received */
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ret = copied;
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goto terminal_message;
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}
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/* last bit of request received */
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if (!(flags & MSG_PEEK)) {
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_debug("eat packet");
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if (skb_dequeue(&rx->sk.sk_receive_queue) !=
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skb)
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BUG();
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rxrpc_free_skb(skb);
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}
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msg->msg_flags &= ~MSG_MORE;
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break;
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}
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/* move on to the next data message */
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_debug("next");
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if (!continue_call)
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continue_call = sp->call;
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else
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rxrpc_put_call(call);
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call = NULL;
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if (flags & MSG_PEEK) {
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_debug("peek next");
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skb = skb->next;
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if (skb == (struct sk_buff *) &rx->sk.sk_receive_queue)
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break;
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goto peek_next_packet;
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}
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_debug("eat packet");
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if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
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BUG();
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rxrpc_free_skb(skb);
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}
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/* end of non-terminal data packet reception for the moment */
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_debug("end rcv data");
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out:
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release_sock(&rx->sk);
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if (call)
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rxrpc_put_call(call);
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if (continue_call)
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rxrpc_put_call(continue_call);
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_leave(" = %d [data]", copied);
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return copied;
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/* handle non-DATA messages such as aborts, incoming connections and
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* final ACKs */
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receive_non_data_message:
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_debug("non-data");
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if (skb->mark == RXRPC_SKB_MARK_NEW_CALL) {
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_debug("RECV NEW CALL");
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ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NEW_CALL, 0, &abort_code);
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if (ret < 0)
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goto copy_error;
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if (!(flags & MSG_PEEK)) {
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if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
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BUG();
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rxrpc_free_skb(skb);
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}
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goto out;
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}
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ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
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ullen, &call->user_call_ID);
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if (ret < 0)
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goto copy_error;
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ASSERT(test_bit(RXRPC_CALL_HAS_USERID, &call->flags));
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switch (skb->mark) {
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case RXRPC_SKB_MARK_DATA:
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BUG();
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case RXRPC_SKB_MARK_FINAL_ACK:
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ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ACK, 0, &abort_code);
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break;
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case RXRPC_SKB_MARK_BUSY:
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ret = put_cmsg(msg, SOL_RXRPC, RXRPC_BUSY, 0, &abort_code);
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break;
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case RXRPC_SKB_MARK_REMOTE_ABORT:
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abort_code = call->abort_code;
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ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &abort_code);
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break;
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case RXRPC_SKB_MARK_NET_ERROR:
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_debug("RECV NET ERROR %d", sp->error);
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abort_code = sp->error;
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ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NET_ERROR, 4, &abort_code);
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break;
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case RXRPC_SKB_MARK_LOCAL_ERROR:
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_debug("RECV LOCAL ERROR %d", sp->error);
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abort_code = sp->error;
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ret = put_cmsg(msg, SOL_RXRPC, RXRPC_LOCAL_ERROR, 4,
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&abort_code);
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break;
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default:
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BUG();
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break;
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}
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if (ret < 0)
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goto copy_error;
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terminal_message:
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_debug("terminal");
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msg->msg_flags &= ~MSG_MORE;
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msg->msg_flags |= MSG_EOR;
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if (!(flags & MSG_PEEK)) {
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_net("free terminal skb %p", skb);
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if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
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BUG();
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rxrpc_free_skb(skb);
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rxrpc_remove_user_ID(rx, call);
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}
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release_sock(&rx->sk);
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rxrpc_put_call(call);
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if (continue_call)
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rxrpc_put_call(continue_call);
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_leave(" = %d", ret);
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return ret;
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copy_error:
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_debug("copy error");
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release_sock(&rx->sk);
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rxrpc_put_call(call);
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if (continue_call)
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rxrpc_put_call(continue_call);
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_leave(" = %d", ret);
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return ret;
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csum_copy_error:
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_debug("csum error");
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release_sock(&rx->sk);
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if (continue_call)
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rxrpc_put_call(continue_call);
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rxrpc_kill_skb(skb);
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skb_kill_datagram(&rx->sk, skb, flags);
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rxrpc_put_call(call);
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return -EAGAIN;
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wait_interrupted:
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ret = sock_intr_errno(timeo);
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wait_error:
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finish_wait(rx->sk.sk_sleep, &wait);
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if (continue_call)
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rxrpc_put_call(continue_call);
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if (copied)
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copied = ret;
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_leave(" = %d [waitfail %d]", copied, ret);
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return copied;
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}
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