David Howells <[EMAIL PROTECTED]> wrote:
> > > - recvmsg not supporting MSG_TRUNC is rather weird and really ought to be
> > > fixed one day as its useful to find out the sizeof message pending when
> > > combined with MSG_PEEK
> >
> > Hmmm... I hadn't considered that. I assumed MSG_TRUNC not to be useful as
> > arbitrarily chopping bits out of the request or reply would seem to be
> > pointless.
>
> But why do I need to support MSG_TRUNC? I currently have things arranged so
> that if you do a recvmsg() that doesn't pull everything out of a packet then
> the next time you do a recvmsg() you'll get the next part of the data in that
> packet. MSG_EOR is flagged when recvmsg copies across the last byte of data
> of a particular phase.
Okay... I've rewritten my recvmsg implementation for RxRPC. The one I had
could pull messages belonging to a call off the socket in the wrong order if
two threads both tried to pull simultaneously.
Also:
(1) If there's a sequence of data messages belonging to a particular call on
the receive queue, then recvmsg() will keep eating them until it meets
either a non-data message or a message belonging to a different call or
until it fills the user buffer. If it doesn't fill the user buffer, it
will sleep unless it is non-blocking.
(2) MSG_PEEK operates similarly, but will return immediately if it has put any
data in the buffer rather than waiting for further packets to arrive.
(3) If a packet is only partially consumed in filling a user buffer, then the
shrunken packet will be left on the front of the queue for the next taker.
(4) If there is more data to be had on a call (we haven't copied the last byte
of the last data packet in that phase yet), then MSG_MORE will be flagged.
(5) MSG_EOR will be flagged on the terminal message of a call. No more
messages from that call will be received, and the user ID may be reused.
Patch attached.
David
diff --git a/net/rxrpc/Makefile b/net/rxrpc/Makefile
index 3369534..f12cd28 100644
--- a/net/rxrpc/Makefile
+++ b/net/rxrpc/Makefile
@@ -17,6 +17,7 @@ af-rxrpc-objs := \
ar-local.o \
ar-output.o \
ar-peer.o \
+ ar-recvmsg.o \
ar-security.o \
ar-skbuff.o \
ar-transport.o
diff --git a/net/rxrpc/af_rxrpc.c b/net/rxrpc/af_rxrpc.c
index b25d931..06963e6 100644
--- a/net/rxrpc/af_rxrpc.c
+++ b/net/rxrpc/af_rxrpc.c
@@ -385,217 +385,6 @@ out:
}
/*
- * receive a message from an RxRPC socket
- */
-static 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;
- struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
- struct sk_buff *skb;
- int copy, ret, ullen;
- u32 abort_code;
-
- _enter(",,,%zu,%d", len, flags);
-
- if (flags & (MSG_OOB | MSG_TRUNC))
- return -EOPNOTSUPP;
-
-try_again:
- if (RB_EMPTY_ROOT(&rx->calls) &&
- rx->sk.sk_state != RXRPC_SERVER_LISTENING)
- return -ENODATA;
-
- /* receive the next message from the common Rx queue */
- skb = skb_recv_datagram(&rx->sk, flags, flags & MSG_DONTWAIT, &ret);
- if (!skb) {
- _leave(" = %d", ret);
- return ret;
- }
-
- sp = rxrpc_skb(skb);
- call = sp->call;
- ASSERT(call != NULL);
-
- /* 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 release call");
- rxrpc_free_skb(skb);
- goto try_again;
- }
-
- rxrpc_get_call(call);
-
- /* copy the peer address. */
- if (msg->msg_name && msg->msg_namelen > 0)
- memcpy(&msg->msg_name, &call->conn->trans->peer->srx,
- sizeof(call->conn->trans->peer->srx));
-
- /* set up the control messages */
- ullen = msg->msg_flags & MSG_CMSG_COMPAT ? 4 : sizeof(unsigned long);
-
- sock_recv_timestamp(msg, &rx->sk, skb);
-
- 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 error_requeue_packet;
- goto done;
- }
-
- ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
- ullen, &call->user_call_ID);
- if (ret < 0)
- goto error_requeue_packet;
- ASSERT(test_bit(RXRPC_CALL_HAS_USERID, &call->flags));
-
- switch (skb->mark) {
- case RXRPC_SKB_MARK_DATA:
- _debug("recvmsg DATA #%u { %d, %d }",
- ntohl(sp->hdr.seq), skb->len, sp->offset);
-
- 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);
-
- copy = skb->len - sp->offset;
- if (copy > len)
- copy = len;
-
- if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
- ret = skb_copy_datagram_iovec(skb, sp->offset,
msg->msg_iov,
- copy);
- } else {
- ret = skb_copy_and_csum_datagram_iovec(skb, sp->offset,
- msg->msg_iov);
- if (ret == -EINVAL)
- goto csum_copy_err;
- }
-
- if (ret < 0)
- goto error_requeue_packet;
-
- /* handle piecemeal consumption of data packets */
- sp->offset += copy;
- ret = copy;
-
- if (sp->hdr.flags & RXRPC_LAST_PACKET)
- msg->msg_flags |= MSG_EOR;
-
- if (sp->offset < skb->len) {
- if (!(flags & MSG_PEEK)) {
- skb_queue_head(&rx->sk.sk_receive_queue, skb);
- atomic_add(skb->truesize,
&rx->sk.sk_rmem_alloc);
- }
- } else if (!(flags & MSG_PEEK)) {
- if (call->conn->out_clientflag &&
- sp->hdr.flags & RXRPC_LAST_PACKET)
- goto terminal_message;
- }
- break;
-
- case RXRPC_SKB_MARK_FINAL_ACK:
- ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ACK, 0, &abort_code);
- if (ret < 0)
- goto error_requeue_packet;
- goto terminal_message;
-
- case RXRPC_SKB_MARK_BUSY:
- ret = put_cmsg(msg, SOL_RXRPC, RXRPC_BUSY, 0, &abort_code);
- if (ret < 0)
- goto error_requeue_packet;
- goto terminal_message;
-
- case RXRPC_SKB_MARK_REMOTE_ABORT:
- abort_code = call->abort_code;
- ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT,
- sizeof(abort_code), &abort_code);
- if (ret < 0)
- goto error_requeue_packet;
- goto terminal_message;
-
- 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);
- if (ret < 0)
- goto error_requeue_packet;
- goto terminal_message;
-
- 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);
- if (ret < 0)
- goto error_requeue_packet;
- goto terminal_message;
-
- default:
- BUG();
- break;
- }
-
-done:
- if (!(flags & MSG_PEEK)) {
- rxrpc_kill_skb(skb);
- skb_free_datagram(&rx->sk, skb);
- }
- rxrpc_put_call(call);
- _leave(" = %d", ret);
- return ret;
-
-terminal_message:
- if (!(flags & MSG_PEEK)) {
- _net("free terminal skb %p", skb);
- rxrpc_kill_skb(skb);
- skb_free_datagram(&rx->sk, skb);
- _debug("RELEASE CALL %d", call->debug_id);
-
- /* withdraw the user ID mapping so that it's not seen again in
- * association with that call */
- 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))
- schedule_work(&call->processor);
- read_unlock_bh(&call->state_lock);
- }
- rxrpc_put_call(call);
- msg->msg_flags |= MSG_EOR;
- _leave(" = %d", ret);
- return ret;
-
-error_requeue_packet:
- if (!(flags & MSG_PEEK)) {
- skb_queue_head(&rx->sk.sk_receive_queue, skb);
- atomic_add(skb->truesize, &rx->sk.sk_rmem_alloc);
- }
- rxrpc_put_call(call);
- _leave(" = %d", ret);
- return ret;
-
-csum_copy_err:
- rxrpc_kill_skb(skb);
- skb_kill_datagram(&rx->sk, skb, flags);
- rxrpc_put_call(call);
- if (flags & MSG_DONTWAIT)
- return -EAGAIN;
- goto try_again;
-}
-
-/*
* set RxRPC socket options
*/
static int rxrpc_setsockopt(struct socket *sock, int level, int optname,
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 00ebf1b..213a640 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -580,6 +580,12 @@ extern struct file_operations rxrpc_call_seq_fops;
extern struct file_operations rxrpc_connection_seq_fops;
/*
+ * ar-recvmsg.c
+ */
+extern int rxrpc_recvmsg(struct kiocb *, struct socket *, struct msghdr *,
+ size_t, int);
+
+/*
* ar-security.c
*/
extern int rxrpc_register_security(struct rxrpc_security *);
diff --git a/net/rxrpc/ar-recvmsg.c b/net/rxrpc/ar-recvmsg.c
new file mode 100644
index 0000000..74e08cc
--- /dev/null
+++ b/net/rxrpc/ar-recvmsg.c
@@ -0,0 +1,362 @@
+/* RxRPC recvmsg() implementation
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells ([EMAIL PROTECTED])
+ *
+ * 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 <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
+ */
+static 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))
+ schedule_work(&call->processor);
+ read_unlock_bh(&call->state_lock);
+}
+
+/*
+ * receive a message from an RxRPC socket
+ */
+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, *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) &&
+ rx->sk.sk_state != RXRPC_SERVER_LISTENING) {
+ release_sock(&rx->sk);
+ return -ENODATA;
+ }
+
+ /* get the next message on the Rx queue */
+ skb = skb_peek(&rx->sk.sk_receive_queue);
+ if (!skb) {
+ /* wait for a message to turn up */
+ release_sock(&rx->sk);
+
+ if (msg->msg_flags & MSG_PEEK && copied) {
+ if (continue_call)
+ rxrpc_put_call(continue_call);
+ _leave(" = %d [peekwait]", copied);
+ return copied;
+ }
+
+ prepare_to_wait_exclusive(rx->sk.sk_sleep, &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(rx->sk.sk_sleep, &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_timestamp(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(rx->sk.sk_sleep, &wait);
+ if (continue_call)
+ rxrpc_put_call(continue_call);
+ if (copied)
+ copied = ret;
+ _leave(" = %d [waitfail %d]", copied, ret);
+ return copied;
+
+}
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