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-rw-r--r--net/rxrpc/recvmsg.c555
1 files changed, 555 insertions, 0 deletions
diff --git a/net/rxrpc/recvmsg.c b/net/rxrpc/recvmsg.c
new file mode 100644
index 0000000000..a482f88c5f
--- /dev/null
+++ b/net/rxrpc/recvmsg.c
@@ -0,0 +1,555 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* RxRPC recvmsg() implementation
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/net.h>
+#include <linux/skbuff.h>
+#include <linux/export.h>
+#include <linux/sched/signal.h>
+
+#include <net/sock.h>
+#include <net/af_rxrpc.h>
+#include "ar-internal.h"
+
+/*
+ * Post a call for attention by the socket or kernel service. Further
+ * notifications are suppressed by putting recvmsg_link on a dummy queue.
+ */
+void rxrpc_notify_socket(struct rxrpc_call *call)
+{
+ struct rxrpc_sock *rx;
+ struct sock *sk;
+
+ _enter("%d", call->debug_id);
+
+ if (!list_empty(&call->recvmsg_link))
+ return;
+
+ rcu_read_lock();
+
+ rx = rcu_dereference(call->socket);
+ sk = &rx->sk;
+ if (rx && sk->sk_state < RXRPC_CLOSE) {
+ if (call->notify_rx) {
+ spin_lock(&call->notify_lock);
+ call->notify_rx(sk, call, call->user_call_ID);
+ spin_unlock(&call->notify_lock);
+ } else {
+ spin_lock(&rx->recvmsg_lock);
+ if (list_empty(&call->recvmsg_link)) {
+ rxrpc_get_call(call, rxrpc_call_get_notify_socket);
+ list_add_tail(&call->recvmsg_link, &rx->recvmsg_q);
+ }
+ spin_unlock(&rx->recvmsg_lock);
+
+ if (!sock_flag(sk, SOCK_DEAD)) {
+ _debug("call %ps", sk->sk_data_ready);
+ sk->sk_data_ready(sk);
+ }
+ }
+ }
+
+ rcu_read_unlock();
+ _leave("");
+}
+
+/*
+ * Pass a call terminating message to userspace.
+ */
+static int rxrpc_recvmsg_term(struct rxrpc_call *call, struct msghdr *msg)
+{
+ u32 tmp = 0;
+ int ret;
+
+ switch (call->completion) {
+ case RXRPC_CALL_SUCCEEDED:
+ ret = 0;
+ if (rxrpc_is_service_call(call))
+ ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ACK, 0, &tmp);
+ break;
+ case RXRPC_CALL_REMOTELY_ABORTED:
+ tmp = call->abort_code;
+ ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &tmp);
+ break;
+ case RXRPC_CALL_LOCALLY_ABORTED:
+ tmp = call->abort_code;
+ ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &tmp);
+ break;
+ case RXRPC_CALL_NETWORK_ERROR:
+ tmp = -call->error;
+ ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NET_ERROR, 4, &tmp);
+ break;
+ case RXRPC_CALL_LOCAL_ERROR:
+ tmp = -call->error;
+ ret = put_cmsg(msg, SOL_RXRPC, RXRPC_LOCAL_ERROR, 4, &tmp);
+ break;
+ default:
+ pr_err("Invalid terminal call state %u\n", call->completion);
+ BUG();
+ break;
+ }
+
+ trace_rxrpc_recvdata(call, rxrpc_recvmsg_terminal,
+ call->ackr_window - 1,
+ call->rx_pkt_offset, call->rx_pkt_len, ret);
+ return ret;
+}
+
+/*
+ * Discard a packet we've used up and advance the Rx window by one.
+ */
+static void rxrpc_rotate_rx_window(struct rxrpc_call *call)
+{
+ struct rxrpc_skb_priv *sp;
+ struct sk_buff *skb;
+ rxrpc_serial_t serial;
+ rxrpc_seq_t old_consumed = call->rx_consumed, tseq;
+ bool last;
+ int acked;
+
+ _enter("%d", call->debug_id);
+
+ skb = skb_dequeue(&call->recvmsg_queue);
+ rxrpc_see_skb(skb, rxrpc_skb_see_rotate);
+
+ sp = rxrpc_skb(skb);
+ tseq = sp->hdr.seq;
+ serial = sp->hdr.serial;
+ last = sp->hdr.flags & RXRPC_LAST_PACKET;
+
+ /* Barrier against rxrpc_input_data(). */
+ if (after(tseq, call->rx_consumed))
+ smp_store_release(&call->rx_consumed, tseq);
+
+ rxrpc_free_skb(skb, rxrpc_skb_put_rotate);
+
+ trace_rxrpc_receive(call, last ? rxrpc_receive_rotate_last : rxrpc_receive_rotate,
+ serial, call->rx_consumed);
+
+ if (last)
+ set_bit(RXRPC_CALL_RECVMSG_READ_ALL, &call->flags);
+
+ /* Check to see if there's an ACK that needs sending. */
+ acked = atomic_add_return(call->rx_consumed - old_consumed,
+ &call->ackr_nr_consumed);
+ if (acked > 8 &&
+ !test_and_set_bit(RXRPC_CALL_RX_IS_IDLE, &call->flags))
+ rxrpc_poke_call(call, rxrpc_call_poke_idle);
+}
+
+/*
+ * Decrypt and verify a DATA packet.
+ */
+static int rxrpc_verify_data(struct rxrpc_call *call, struct sk_buff *skb)
+{
+ struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+
+ if (sp->flags & RXRPC_RX_VERIFIED)
+ return 0;
+ return call->security->verify_packet(call, skb);
+}
+
+/*
+ * Deliver messages to a call. This keeps processing packets until the buffer
+ * is filled and we find either more DATA (returns 0) or the end of the DATA
+ * (returns 1). If more packets are required, it returns -EAGAIN and if the
+ * call has failed it returns -EIO.
+ */
+static int rxrpc_recvmsg_data(struct socket *sock, struct rxrpc_call *call,
+ struct msghdr *msg, struct iov_iter *iter,
+ size_t len, int flags, size_t *_offset)
+{
+ struct rxrpc_skb_priv *sp;
+ struct sk_buff *skb;
+ rxrpc_seq_t seq = 0;
+ size_t remain;
+ unsigned int rx_pkt_offset, rx_pkt_len;
+ int copy, ret = -EAGAIN, ret2;
+
+ rx_pkt_offset = call->rx_pkt_offset;
+ rx_pkt_len = call->rx_pkt_len;
+
+ if (rxrpc_call_has_failed(call)) {
+ seq = call->ackr_window - 1;
+ ret = -EIO;
+ goto done;
+ }
+
+ if (test_bit(RXRPC_CALL_RECVMSG_READ_ALL, &call->flags)) {
+ seq = call->ackr_window - 1;
+ ret = 1;
+ goto done;
+ }
+
+ /* No one else can be removing stuff from the queue, so we shouldn't
+ * need the Rx lock to walk it.
+ */
+ skb = skb_peek(&call->recvmsg_queue);
+ while (skb) {
+ rxrpc_see_skb(skb, rxrpc_skb_see_recvmsg);
+ sp = rxrpc_skb(skb);
+ seq = sp->hdr.seq;
+
+ if (!(flags & MSG_PEEK))
+ trace_rxrpc_receive(call, rxrpc_receive_front,
+ sp->hdr.serial, seq);
+
+ if (msg)
+ sock_recv_timestamp(msg, sock->sk, skb);
+
+ if (rx_pkt_offset == 0) {
+ ret2 = rxrpc_verify_data(call, skb);
+ trace_rxrpc_recvdata(call, rxrpc_recvmsg_next, seq,
+ sp->offset, sp->len, ret2);
+ if (ret2 < 0) {
+ kdebug("verify = %d", ret2);
+ ret = ret2;
+ goto out;
+ }
+ rx_pkt_offset = sp->offset;
+ rx_pkt_len = sp->len;
+ } else {
+ trace_rxrpc_recvdata(call, rxrpc_recvmsg_cont, seq,
+ rx_pkt_offset, rx_pkt_len, 0);
+ }
+
+ /* We have to handle short, empty and used-up DATA packets. */
+ remain = len - *_offset;
+ copy = rx_pkt_len;
+ if (copy > remain)
+ copy = remain;
+ if (copy > 0) {
+ ret2 = skb_copy_datagram_iter(skb, rx_pkt_offset, iter,
+ copy);
+ if (ret2 < 0) {
+ ret = ret2;
+ goto out;
+ }
+
+ /* handle piecemeal consumption of data packets */
+ rx_pkt_offset += copy;
+ rx_pkt_len -= copy;
+ *_offset += copy;
+ }
+
+ if (rx_pkt_len > 0) {
+ trace_rxrpc_recvdata(call, rxrpc_recvmsg_full, seq,
+ rx_pkt_offset, rx_pkt_len, 0);
+ ASSERTCMP(*_offset, ==, len);
+ ret = 0;
+ break;
+ }
+
+ /* The whole packet has been transferred. */
+ if (sp->hdr.flags & RXRPC_LAST_PACKET)
+ ret = 1;
+ rx_pkt_offset = 0;
+ rx_pkt_len = 0;
+
+ skb = skb_peek_next(skb, &call->recvmsg_queue);
+
+ if (!(flags & MSG_PEEK))
+ rxrpc_rotate_rx_window(call);
+ }
+
+out:
+ if (!(flags & MSG_PEEK)) {
+ call->rx_pkt_offset = rx_pkt_offset;
+ call->rx_pkt_len = rx_pkt_len;
+ }
+done:
+ trace_rxrpc_recvdata(call, rxrpc_recvmsg_data_return, seq,
+ rx_pkt_offset, rx_pkt_len, ret);
+ if (ret == -EAGAIN)
+ set_bit(RXRPC_CALL_RX_IS_IDLE, &call->flags);
+ return ret;
+}
+
+/*
+ * Receive a message from an RxRPC socket
+ * - we need to be careful about two or more threads calling recvmsg
+ * simultaneously
+ */
+int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
+ int flags)
+{
+ struct rxrpc_call *call;
+ struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
+ struct list_head *l;
+ unsigned int call_debug_id = 0;
+ size_t copied = 0;
+ long timeo;
+ int ret;
+
+ DEFINE_WAIT(wait);
+
+ trace_rxrpc_recvmsg(0, rxrpc_recvmsg_enter, 0);
+
+ if (flags & (MSG_OOB | MSG_TRUNC))
+ return -EOPNOTSUPP;
+
+ timeo = sock_rcvtimeo(&rx->sk, flags & MSG_DONTWAIT);
+
+try_again:
+ lock_sock(&rx->sk);
+
+ /* Return immediately if a client socket has no outstanding calls */
+ if (RB_EMPTY_ROOT(&rx->calls) &&
+ list_empty(&rx->recvmsg_q) &&
+ rx->sk.sk_state != RXRPC_SERVER_LISTENING) {
+ release_sock(&rx->sk);
+ return -EAGAIN;
+ }
+
+ if (list_empty(&rx->recvmsg_q)) {
+ ret = -EWOULDBLOCK;
+ if (timeo == 0) {
+ call = NULL;
+ goto error_no_call;
+ }
+
+ release_sock(&rx->sk);
+
+ /* Wait for something to happen */
+ prepare_to_wait_exclusive(sk_sleep(&rx->sk), &wait,
+ TASK_INTERRUPTIBLE);
+ ret = sock_error(&rx->sk);
+ if (ret)
+ goto wait_error;
+
+ if (list_empty(&rx->recvmsg_q)) {
+ if (signal_pending(current))
+ goto wait_interrupted;
+ trace_rxrpc_recvmsg(0, rxrpc_recvmsg_wait, 0);
+ timeo = schedule_timeout(timeo);
+ }
+ finish_wait(sk_sleep(&rx->sk), &wait);
+ goto try_again;
+ }
+
+ /* Find the next call and dequeue it if we're not just peeking. If we
+ * do dequeue it, that comes with a ref that we will need to release.
+ * We also want to weed out calls that got requeued whilst we were
+ * shovelling data out.
+ */
+ spin_lock(&rx->recvmsg_lock);
+ l = rx->recvmsg_q.next;
+ call = list_entry(l, struct rxrpc_call, recvmsg_link);
+
+ if (!rxrpc_call_is_complete(call) &&
+ skb_queue_empty(&call->recvmsg_queue)) {
+ list_del_init(&call->recvmsg_link);
+ spin_unlock(&rx->recvmsg_lock);
+ release_sock(&rx->sk);
+ trace_rxrpc_recvmsg(call->debug_id, rxrpc_recvmsg_unqueue, 0);
+ rxrpc_put_call(call, rxrpc_call_put_recvmsg);
+ goto try_again;
+ }
+
+ if (!(flags & MSG_PEEK))
+ list_del_init(&call->recvmsg_link);
+ else
+ rxrpc_get_call(call, rxrpc_call_get_recvmsg);
+ spin_unlock(&rx->recvmsg_lock);
+
+ call_debug_id = call->debug_id;
+ trace_rxrpc_recvmsg(call_debug_id, rxrpc_recvmsg_dequeue, 0);
+
+ /* We're going to drop the socket lock, so we need to lock the call
+ * against interference by sendmsg.
+ */
+ if (!mutex_trylock(&call->user_mutex)) {
+ ret = -EWOULDBLOCK;
+ if (flags & MSG_DONTWAIT)
+ goto error_requeue_call;
+ ret = -ERESTARTSYS;
+ if (mutex_lock_interruptible(&call->user_mutex) < 0)
+ goto error_requeue_call;
+ }
+
+ release_sock(&rx->sk);
+
+ if (test_bit(RXRPC_CALL_RELEASED, &call->flags))
+ BUG();
+
+ if (test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
+ if (flags & MSG_CMSG_COMPAT) {
+ unsigned int id32 = call->user_call_ID;
+
+ ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
+ sizeof(unsigned int), &id32);
+ } else {
+ unsigned long idl = call->user_call_ID;
+
+ ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
+ sizeof(unsigned long), &idl);
+ }
+ if (ret < 0)
+ goto error_unlock_call;
+ }
+
+ if (msg->msg_name && call->peer) {
+ size_t len = sizeof(call->dest_srx);
+
+ memcpy(msg->msg_name, &call->dest_srx, len);
+ msg->msg_namelen = len;
+ }
+
+ ret = rxrpc_recvmsg_data(sock, call, msg, &msg->msg_iter, len,
+ flags, &copied);
+ if (ret == -EAGAIN)
+ ret = 0;
+ if (ret == -EIO)
+ goto call_failed;
+ if (ret < 0)
+ goto error_unlock_call;
+
+ if (rxrpc_call_is_complete(call) &&
+ skb_queue_empty(&call->recvmsg_queue))
+ goto call_complete;
+ if (rxrpc_call_has_failed(call))
+ goto call_failed;
+
+ if (!skb_queue_empty(&call->recvmsg_queue))
+ rxrpc_notify_socket(call);
+ goto not_yet_complete;
+
+call_failed:
+ rxrpc_purge_queue(&call->recvmsg_queue);
+call_complete:
+ ret = rxrpc_recvmsg_term(call, msg);
+ if (ret < 0)
+ goto error_unlock_call;
+ if (!(flags & MSG_PEEK))
+ rxrpc_release_call(rx, call);
+ msg->msg_flags |= MSG_EOR;
+ ret = 1;
+
+not_yet_complete:
+ if (ret == 0)
+ msg->msg_flags |= MSG_MORE;
+ else
+ msg->msg_flags &= ~MSG_MORE;
+ ret = copied;
+
+error_unlock_call:
+ mutex_unlock(&call->user_mutex);
+ rxrpc_put_call(call, rxrpc_call_put_recvmsg);
+ trace_rxrpc_recvmsg(call_debug_id, rxrpc_recvmsg_return, ret);
+ return ret;
+
+error_requeue_call:
+ if (!(flags & MSG_PEEK)) {
+ spin_lock(&rx->recvmsg_lock);
+ list_add(&call->recvmsg_link, &rx->recvmsg_q);
+ spin_unlock(&rx->recvmsg_lock);
+ trace_rxrpc_recvmsg(call_debug_id, rxrpc_recvmsg_requeue, 0);
+ } else {
+ rxrpc_put_call(call, rxrpc_call_put_recvmsg);
+ }
+error_no_call:
+ release_sock(&rx->sk);
+error_trace:
+ trace_rxrpc_recvmsg(call_debug_id, rxrpc_recvmsg_return, ret);
+ return ret;
+
+wait_interrupted:
+ ret = sock_intr_errno(timeo);
+wait_error:
+ finish_wait(sk_sleep(&rx->sk), &wait);
+ call = NULL;
+ goto error_trace;
+}
+
+/**
+ * rxrpc_kernel_recv_data - Allow a kernel service to receive data/info
+ * @sock: The socket that the call exists on
+ * @call: The call to send data through
+ * @iter: The buffer to receive into
+ * @_len: The amount of data we want to receive (decreased on return)
+ * @want_more: True if more data is expected to be read
+ * @_abort: Where the abort code is stored if -ECONNABORTED is returned
+ * @_service: Where to store the actual service ID (may be upgraded)
+ *
+ * Allow a kernel service to receive data and pick up information about the
+ * state of a call. Returns 0 if got what was asked for and there's more
+ * available, 1 if we got what was asked for and we're at the end of the data
+ * and -EAGAIN if we need more data.
+ *
+ * Note that we may return -EAGAIN to drain empty packets at the end of the
+ * data, even if we've already copied over the requested data.
+ *
+ * *_abort should also be initialised to 0.
+ */
+int rxrpc_kernel_recv_data(struct socket *sock, struct rxrpc_call *call,
+ struct iov_iter *iter, size_t *_len,
+ bool want_more, u32 *_abort, u16 *_service)
+{
+ size_t offset = 0;
+ int ret;
+
+ _enter("{%d},%zu,%d", call->debug_id, *_len, want_more);
+
+ mutex_lock(&call->user_mutex);
+
+ ret = rxrpc_recvmsg_data(sock, call, NULL, iter, *_len, 0, &offset);
+ *_len -= offset;
+ if (ret == -EIO)
+ goto call_failed;
+ if (ret < 0)
+ goto out;
+
+ /* We can only reach here with a partially full buffer if we have
+ * reached the end of the data. We must otherwise have a full buffer
+ * or have been given -EAGAIN.
+ */
+ if (ret == 1) {
+ if (iov_iter_count(iter) > 0)
+ goto short_data;
+ if (!want_more)
+ goto read_phase_complete;
+ ret = 0;
+ goto out;
+ }
+
+ if (!want_more)
+ goto excess_data;
+ goto out;
+
+read_phase_complete:
+ ret = 1;
+out:
+ if (_service)
+ *_service = call->dest_srx.srx_service;
+ mutex_unlock(&call->user_mutex);
+ _leave(" = %d [%zu,%d]", ret, iov_iter_count(iter), *_abort);
+ return ret;
+
+short_data:
+ trace_rxrpc_abort(call->debug_id, rxrpc_recvmsg_short_data,
+ call->cid, call->call_id, call->rx_consumed,
+ 0, -EBADMSG);
+ ret = -EBADMSG;
+ goto out;
+excess_data:
+ trace_rxrpc_abort(call->debug_id, rxrpc_recvmsg_excess_data,
+ call->cid, call->call_id, call->rx_consumed,
+ 0, -EMSGSIZE);
+ ret = -EMSGSIZE;
+ goto out;
+call_failed:
+ *_abort = call->abort_code;
+ ret = call->error;
+ if (call->completion == RXRPC_CALL_SUCCEEDED) {
+ ret = 1;
+ if (iov_iter_count(iter) > 0)
+ ret = -ECONNRESET;
+ }
+ goto out;
+}
+EXPORT_SYMBOL(rxrpc_kernel_recv_data);