kernel-hacking-2024-linux-s.../net/rxrpc/insecure.c
David Howells a4ea4c4776 rxrpc: Don't use a ring buffer for call Tx queue
Change the way the Tx queueing works to make the following ends easier to
achieve:

 (1) The filling of packets, the encryption of packets and the transmission
     of packets can be handled in parallel by separate threads, rather than
     rxrpc_sendmsg() allocating, filling, encrypting and transmitting each
     packet before moving onto the next one.

 (2) Get rid of the fixed-size ring which sets a hard limit on the number
     of packets that can be retained in the ring.  This allows the number
     of packets to increase without having to allocate a very large ring or
     having variable-sized rings.

     [Note: the downside of this is that it's then less efficient to locate
     a packet for retransmission as we then have to step through a list and
     examine each buffer in the list.]

 (3) Allow the filler/encrypter to run ahead of the transmission window.

 (4) Make it easier to do zero copy UDP from the packet buffers.

 (5) Make it easier to do zero copy from userspace to the packet buffers -
     and thence to UDP (only if for unauthenticated connections).

To that end, the following changes are made:

 (1) Use the new rxrpc_txbuf struct instead of sk_buff for keeping packets
     to be transmitted in.  This allows them to be placed on multiple
     queues simultaneously.  An sk_buff isn't really necessary as it's
     never passed on to lower-level networking code.

 (2) Keep the transmissable packets in a linked list on the call struct
     rather than in a ring.  As a consequence, the annotation buffer isn't
     used either; rather a flag is set on the packet to indicate ackedness.

 (3) Use the RXRPC_CALL_TX_LAST flag to indicate that the last packet to be
     transmitted has been queued.  Add RXRPC_CALL_TX_ALL_ACKED to indicate
     that all packets up to and including the last got hard acked.

 (4) Wire headers are now stored in the txbuf rather than being concocted
     on the stack and they're stored immediately before the data, thereby
     allowing zerocopy of a single span.

 (5) Don't bother with instant-resend on transmission failure; rather,
     leave it for a timer or an ACK packet to trigger.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-11-08 16:42:28 +00:00

96 lines
2.2 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/* Null security operations.
*
* Copyright (C) 2016 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#include <net/af_rxrpc.h>
#include "ar-internal.h"
static int none_init_connection_security(struct rxrpc_connection *conn,
struct rxrpc_key_token *token)
{
return 0;
}
/*
* Work out how much data we can put in an unsecured packet.
*/
static int none_how_much_data(struct rxrpc_call *call, size_t remain,
size_t *_buf_size, size_t *_data_size, size_t *_offset)
{
*_buf_size = *_data_size = min_t(size_t, remain, RXRPC_JUMBO_DATALEN);
*_offset = 0;
return 0;
}
static int none_secure_packet(struct rxrpc_call *call, struct rxrpc_txbuf *txb)
{
return 0;
}
static int none_verify_packet(struct rxrpc_call *call, struct sk_buff *skb)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
sp->flags |= RXRPC_RX_VERIFIED;
return 0;
}
static void none_free_call_crypto(struct rxrpc_call *call)
{
}
static int none_respond_to_challenge(struct rxrpc_connection *conn,
struct sk_buff *skb,
u32 *_abort_code)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
tracepoint_string("chall_none"));
return -EPROTO;
}
static int none_verify_response(struct rxrpc_connection *conn,
struct sk_buff *skb,
u32 *_abort_code)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
tracepoint_string("resp_none"));
return -EPROTO;
}
static void none_clear(struct rxrpc_connection *conn)
{
}
static int none_init(void)
{
return 0;
}
static void none_exit(void)
{
}
/*
* RxRPC Kerberos-based security
*/
const struct rxrpc_security rxrpc_no_security = {
.name = "none",
.security_index = RXRPC_SECURITY_NONE,
.init = none_init,
.exit = none_exit,
.init_connection_security = none_init_connection_security,
.free_call_crypto = none_free_call_crypto,
.how_much_data = none_how_much_data,
.secure_packet = none_secure_packet,
.verify_packet = none_verify_packet,
.respond_to_challenge = none_respond_to_challenge,
.verify_response = none_verify_response,
.clear = none_clear,
};