linux/net/rxrpc/ar-local.c
David Howells 0d12f8a402 rxrpc: Keep the skb private record of the Rx header in host byte order
Currently, a copy of the Rx packet header is copied into the the sk_buff
private data so that we can advance the pointer into the buffer,
potentially discarding the original.  At the moment, this copy is held in
network byte order, but this means we're doing a lot of unnecessary
translations.

The reasons it was done this way are that we need the values in network
byte order occasionally and we can use the copy, slightly modified, as part
of an iov array when sending an ack or an abort packet.

However, it seems more reasonable on review that it would be better kept in
host byte order and that we make up a new header when we want to send
another packet.

To this end, rename the original header struct to rxrpc_wire_header (with
BE fields) and institute a variant called rxrpc_host_header that has host
order fields.  Change the struct in the sk_buff private data into an
rxrpc_host_header and translate the values when filling it in.

This further allows us to keep values kept in various structures in host
byte order rather than network byte order and allows removal of some fields
that are byteswapped duplicates.

Signed-off-by: David Howells <dhowells@redhat.com>
2016-03-04 15:53:46 +00:00

416 lines
10 KiB
C

/* AF_RXRPC local endpoint management
*
* 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/module.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/udp.h>
#include <linux/ip.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include <generated/utsrelease.h>
#include "ar-internal.h"
static const char rxrpc_version_string[65] = "linux-" UTS_RELEASE " AF_RXRPC";
static LIST_HEAD(rxrpc_locals);
DEFINE_RWLOCK(rxrpc_local_lock);
static DECLARE_RWSEM(rxrpc_local_sem);
static DECLARE_WAIT_QUEUE_HEAD(rxrpc_local_wq);
static void rxrpc_destroy_local(struct work_struct *work);
static void rxrpc_process_local_events(struct work_struct *work);
/*
* allocate a new local
*/
static
struct rxrpc_local *rxrpc_alloc_local(struct sockaddr_rxrpc *srx)
{
struct rxrpc_local *local;
local = kzalloc(sizeof(struct rxrpc_local), GFP_KERNEL);
if (local) {
INIT_WORK(&local->destroyer, &rxrpc_destroy_local);
INIT_WORK(&local->acceptor, &rxrpc_accept_incoming_calls);
INIT_WORK(&local->rejecter, &rxrpc_reject_packets);
INIT_WORK(&local->event_processor, &rxrpc_process_local_events);
INIT_LIST_HEAD(&local->services);
INIT_LIST_HEAD(&local->link);
init_rwsem(&local->defrag_sem);
skb_queue_head_init(&local->accept_queue);
skb_queue_head_init(&local->reject_queue);
skb_queue_head_init(&local->event_queue);
spin_lock_init(&local->lock);
rwlock_init(&local->services_lock);
atomic_set(&local->usage, 1);
local->debug_id = atomic_inc_return(&rxrpc_debug_id);
memcpy(&local->srx, srx, sizeof(*srx));
}
_leave(" = %p", local);
return local;
}
/*
* create the local socket
* - must be called with rxrpc_local_sem writelocked
*/
static int rxrpc_create_local(struct rxrpc_local *local)
{
struct sock *sock;
int ret, opt;
_enter("%p{%d}", local, local->srx.transport_type);
/* create a socket to represent the local endpoint */
ret = sock_create_kern(&init_net, PF_INET, local->srx.transport_type,
IPPROTO_UDP, &local->socket);
if (ret < 0) {
_leave(" = %d [socket]", ret);
return ret;
}
/* if a local address was supplied then bind it */
if (local->srx.transport_len > sizeof(sa_family_t)) {
_debug("bind");
ret = kernel_bind(local->socket,
(struct sockaddr *) &local->srx.transport,
local->srx.transport_len);
if (ret < 0) {
_debug("bind failed");
goto error;
}
}
/* we want to receive ICMP errors */
opt = 1;
ret = kernel_setsockopt(local->socket, SOL_IP, IP_RECVERR,
(char *) &opt, sizeof(opt));
if (ret < 0) {
_debug("setsockopt failed");
goto error;
}
/* we want to set the don't fragment bit */
opt = IP_PMTUDISC_DO;
ret = kernel_setsockopt(local->socket, SOL_IP, IP_MTU_DISCOVER,
(char *) &opt, sizeof(opt));
if (ret < 0) {
_debug("setsockopt failed");
goto error;
}
write_lock_bh(&rxrpc_local_lock);
list_add(&local->link, &rxrpc_locals);
write_unlock_bh(&rxrpc_local_lock);
/* set the socket up */
sock = local->socket->sk;
sock->sk_user_data = local;
sock->sk_data_ready = rxrpc_data_ready;
sock->sk_error_report = rxrpc_UDP_error_report;
_leave(" = 0");
return 0;
error:
kernel_sock_shutdown(local->socket, SHUT_RDWR);
local->socket->sk->sk_user_data = NULL;
sock_release(local->socket);
local->socket = NULL;
_leave(" = %d", ret);
return ret;
}
/*
* create a new local endpoint using the specified UDP address
*/
struct rxrpc_local *rxrpc_lookup_local(struct sockaddr_rxrpc *srx)
{
struct rxrpc_local *local;
int ret;
_enter("{%d,%u,%pI4+%hu}",
srx->transport_type,
srx->transport.family,
&srx->transport.sin.sin_addr,
ntohs(srx->transport.sin.sin_port));
down_write(&rxrpc_local_sem);
/* see if we have a suitable local local endpoint already */
read_lock_bh(&rxrpc_local_lock);
list_for_each_entry(local, &rxrpc_locals, link) {
_debug("CMP {%d,%u,%pI4+%hu}",
local->srx.transport_type,
local->srx.transport.family,
&local->srx.transport.sin.sin_addr,
ntohs(local->srx.transport.sin.sin_port));
if (local->srx.transport_type != srx->transport_type ||
local->srx.transport.family != srx->transport.family)
continue;
switch (srx->transport.family) {
case AF_INET:
if (local->srx.transport.sin.sin_port !=
srx->transport.sin.sin_port)
continue;
if (memcmp(&local->srx.transport.sin.sin_addr,
&srx->transport.sin.sin_addr,
sizeof(struct in_addr)) != 0)
continue;
goto found_local;
default:
BUG();
}
}
read_unlock_bh(&rxrpc_local_lock);
/* we didn't find one, so we need to create one */
local = rxrpc_alloc_local(srx);
if (!local) {
up_write(&rxrpc_local_sem);
return ERR_PTR(-ENOMEM);
}
ret = rxrpc_create_local(local);
if (ret < 0) {
up_write(&rxrpc_local_sem);
kfree(local);
_leave(" = %d", ret);
return ERR_PTR(ret);
}
up_write(&rxrpc_local_sem);
_net("LOCAL new %d {%d,%u,%pI4+%hu}",
local->debug_id,
local->srx.transport_type,
local->srx.transport.family,
&local->srx.transport.sin.sin_addr,
ntohs(local->srx.transport.sin.sin_port));
_leave(" = %p [new]", local);
return local;
found_local:
rxrpc_get_local(local);
read_unlock_bh(&rxrpc_local_lock);
up_write(&rxrpc_local_sem);
_net("LOCAL old %d {%d,%u,%pI4+%hu}",
local->debug_id,
local->srx.transport_type,
local->srx.transport.family,
&local->srx.transport.sin.sin_addr,
ntohs(local->srx.transport.sin.sin_port));
_leave(" = %p [reuse]", local);
return local;
}
/*
* release a local endpoint
*/
void rxrpc_put_local(struct rxrpc_local *local)
{
_enter("%p{u=%d}", local, atomic_read(&local->usage));
ASSERTCMP(atomic_read(&local->usage), >, 0);
/* to prevent a race, the decrement and the dequeue must be effectively
* atomic */
write_lock_bh(&rxrpc_local_lock);
if (unlikely(atomic_dec_and_test(&local->usage))) {
_debug("destroy local");
rxrpc_queue_work(&local->destroyer);
}
write_unlock_bh(&rxrpc_local_lock);
_leave("");
}
/*
* destroy a local endpoint
*/
static void rxrpc_destroy_local(struct work_struct *work)
{
struct rxrpc_local *local =
container_of(work, struct rxrpc_local, destroyer);
_enter("%p{%d}", local, atomic_read(&local->usage));
down_write(&rxrpc_local_sem);
write_lock_bh(&rxrpc_local_lock);
if (atomic_read(&local->usage) > 0) {
write_unlock_bh(&rxrpc_local_lock);
up_read(&rxrpc_local_sem);
_leave(" [resurrected]");
return;
}
list_del(&local->link);
local->socket->sk->sk_user_data = NULL;
write_unlock_bh(&rxrpc_local_lock);
downgrade_write(&rxrpc_local_sem);
ASSERT(list_empty(&local->services));
ASSERT(!work_pending(&local->acceptor));
ASSERT(!work_pending(&local->rejecter));
ASSERT(!work_pending(&local->event_processor));
/* finish cleaning up the local descriptor */
rxrpc_purge_queue(&local->accept_queue);
rxrpc_purge_queue(&local->reject_queue);
rxrpc_purge_queue(&local->event_queue);
kernel_sock_shutdown(local->socket, SHUT_RDWR);
sock_release(local->socket);
up_read(&rxrpc_local_sem);
_net("DESTROY LOCAL %d", local->debug_id);
kfree(local);
if (list_empty(&rxrpc_locals))
wake_up_all(&rxrpc_local_wq);
_leave("");
}
/*
* preemptively destroy all local local endpoint rather than waiting for
* them to be destroyed
*/
void __exit rxrpc_destroy_all_locals(void)
{
DECLARE_WAITQUEUE(myself,current);
_enter("");
/* we simply have to wait for them to go away */
if (!list_empty(&rxrpc_locals)) {
set_current_state(TASK_UNINTERRUPTIBLE);
add_wait_queue(&rxrpc_local_wq, &myself);
while (!list_empty(&rxrpc_locals)) {
schedule();
set_current_state(TASK_UNINTERRUPTIBLE);
}
remove_wait_queue(&rxrpc_local_wq, &myself);
set_current_state(TASK_RUNNING);
}
_leave("");
}
/*
* Reply to a version request
*/
static void rxrpc_send_version_request(struct rxrpc_local *local,
struct rxrpc_host_header *hdr,
struct sk_buff *skb)
{
struct rxrpc_wire_header whdr;
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
struct sockaddr_in sin;
struct msghdr msg;
struct kvec iov[2];
size_t len;
int ret;
_enter("");
sin.sin_family = AF_INET;
sin.sin_port = udp_hdr(skb)->source;
sin.sin_addr.s_addr = ip_hdr(skb)->saddr;
msg.msg_name = &sin;
msg.msg_namelen = sizeof(sin);
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
whdr.epoch = htonl(sp->hdr.epoch);
whdr.cid = htonl(sp->hdr.cid);
whdr.callNumber = htonl(sp->hdr.callNumber);
whdr.seq = 0;
whdr.serial = 0;
whdr.type = RXRPC_PACKET_TYPE_VERSION;
whdr.flags = RXRPC_LAST_PACKET | (~hdr->flags & RXRPC_CLIENT_INITIATED);
whdr.userStatus = 0;
whdr.securityIndex = 0;
whdr._rsvd = 0;
whdr.serviceId = htons(sp->hdr.serviceId);
iov[0].iov_base = &whdr;
iov[0].iov_len = sizeof(whdr);
iov[1].iov_base = (char *)rxrpc_version_string;
iov[1].iov_len = sizeof(rxrpc_version_string);
len = iov[0].iov_len + iov[1].iov_len;
_proto("Tx VERSION (reply)");
ret = kernel_sendmsg(local->socket, &msg, iov, 2, len);
if (ret < 0)
_debug("sendmsg failed: %d", ret);
_leave("");
}
/*
* Process event packets targetted at a local endpoint.
*/
static void rxrpc_process_local_events(struct work_struct *work)
{
struct rxrpc_local *local = container_of(work, struct rxrpc_local, event_processor);
struct sk_buff *skb;
char v;
_enter("");
atomic_inc(&local->usage);
while ((skb = skb_dequeue(&local->event_queue))) {
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
_debug("{%d},{%u}", local->debug_id, sp->hdr.type);
switch (sp->hdr.type) {
case RXRPC_PACKET_TYPE_VERSION:
if (skb_copy_bits(skb, 0, &v, 1) < 0)
return;
_proto("Rx VERSION { %02x }", v);
if (v == 0)
rxrpc_send_version_request(local, &sp->hdr, skb);
break;
default:
/* Just ignore anything we don't understand */
break;
}
rxrpc_put_local(local);
rxrpc_free_skb(skb);
}
rxrpc_put_local(local);
_leave("");
}