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