q3k/linux
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity
linux/net/caif/caif_socket.c
Mel Gorman c76562b670 netvm: prevent a stream-specific deadlock 
This patch series is based on top of "Swap-over-NBD without deadlocking
v15" as it depends on the same reservation of PF_MEMALLOC reserves logic.

When a user or administrator requires swap for their application, they
create a swap partition and file, format it with mkswap and activate it
with swapon.  In diskless systems this is not an option so if swap if
required then swapping over the network is considered.  The two likely
scenarios are when blade servers are used as part of a cluster where the
form factor or maintenance costs do not allow the use of disks and thin
clients.

The Linux Terminal Server Project recommends the use of the Network Block
Device (NBD) for swap but this is not always an option.  There is no
guarantee that the network attached storage (NAS) device is running Linux
or supports NBD.  However, it is likely that it supports NFS so there are
users that want support for swapping over NFS despite any performance
concern.  Some distributions currently carry patches that support swapping
over NFS but it would be preferable to support it in the mainline kernel.

Patch 1 avoids a stream-specific deadlock that potentially affects TCP.

Patch 2 is a small modification to SELinux to avoid using PFMEMALLOC
	reserves.

Patch 3 adds three helpers for filesystems to handle swap cache pages.
	For example, page_file_mapping() returns page->mapping for
	file-backed pages and the address_space of the underlying
	swap file for swap cache pages.

Patch 4 adds two address_space_operations to allow a filesystem
	to pin all metadata relevant to a swapfile in memory. Upon
	successful activation, the swapfile is marked SWP_FILE and
	the address space operation ->direct_IO is used for writing
	and ->readpage for reading in swap pages.

Patch 5 notes that patch 3 is bolting
	filesystem-specific-swapfile-support onto the side and that
	the default handlers have different information to what
	is available to the filesystem. This patch refactors the
	code so that there are generic handlers for each of the new
	address_space operations.

Patch 6 adds an API to allow a vector of kernel addresses to be
	translated to struct pages and pinned for IO.

Patch 7 adds support for using highmem pages for swap by kmapping
	the pages before calling the direct_IO handler.

Patch 8 updates NFS to use the helpers from patch 3 where necessary.

Patch 9 avoids setting PF_private on PG_swapcache pages within NFS.

Patch 10 implements the new swapfile-related address_space operations
	for NFS and teaches the direct IO handler how to manage
	kernel addresses.

Patch 11 prevents page allocator recursions in NFS by using GFP_NOIO
	where appropriate.

Patch 12 fixes a NULL pointer dereference that occurs when using
	swap-over-NFS.

With the patches applied, it is possible to mount a swapfile that is on an
NFS filesystem.  Swap performance is not great with a swap stress test
taking roughly twice as long to complete than if the swap device was
backed by NBD.

This patch: netvm: prevent a stream-specific deadlock

It could happen that all !SOCK_MEMALLOC sockets have buffered so much data
that we're over the global rmem limit.  This will prevent SOCK_MEMALLOC
buffers from receiving data, which will prevent userspace from running,
which is needed to reduce the buffered data.

Fix this by exempting the SOCK_MEMALLOC sockets from the rmem limit.  Once
this change it applied, it is important that sockets that set
SOCK_MEMALLOC do not clear the flag until the socket is being torn down.
If this happens, a warning is generated and the tokens reclaimed to avoid
accounting errors until the bug is fixed.

[davem@davemloft.net: Warning about clearing SOCK_MEMALLOC]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-31 18:42:47 -07:00

1122 lines
27 KiB
C
Raw Blame History

/*
* Copyright (C) ST-Ericsson AB 2010
* Author: Sjur Brendeland sjur.brandeland@stericsson.com
* License terms: GNU General Public License (GPL) version 2
*/
#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/wait.h>
#include <linux/poll.h>
#include <linux/tcp.h>
#include <linux/uaccess.h>
#include <linux/debugfs.h>
#include <linux/caif/caif_socket.h>
#include <linux/pkt_sched.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <net/caif/caif_layer.h>
#include <net/caif/caif_dev.h>
#include <net/caif/cfpkt.h>
MODULE_LICENSE("GPL");
MODULE_ALIAS_NETPROTO(AF_CAIF);
/*
* CAIF state is re-using the TCP socket states.
* caif_states stored in sk_state reflect the state as reported by
* the CAIF stack, while sk_socket->state is the state of the socket.
*/
enum caif_states {
CAIF_CONNECTED = TCP_ESTABLISHED,
CAIF_CONNECTING = TCP_SYN_SENT,
CAIF_DISCONNECTED = TCP_CLOSE
};
#define TX_FLOW_ON_BIT 1
#define RX_FLOW_ON_BIT 2
struct caifsock {
struct sock sk; /* must be first member */
struct cflayer layer;
u32 flow_state;
struct caif_connect_request conn_req;
struct mutex readlock;
struct dentry *debugfs_socket_dir;
int headroom, tailroom, maxframe;
};
static int rx_flow_is_on(struct caifsock *cf_sk)
{
return test_bit(RX_FLOW_ON_BIT,
(void *) &cf_sk->flow_state);
}
static int tx_flow_is_on(struct caifsock *cf_sk)
{
return test_bit(TX_FLOW_ON_BIT,
(void *) &cf_sk->flow_state);
}
static void set_rx_flow_off(struct caifsock *cf_sk)
{
clear_bit(RX_FLOW_ON_BIT,
(void *) &cf_sk->flow_state);
}
static void set_rx_flow_on(struct caifsock *cf_sk)
{
set_bit(RX_FLOW_ON_BIT,
(void *) &cf_sk->flow_state);
}
static void set_tx_flow_off(struct caifsock *cf_sk)
{
clear_bit(TX_FLOW_ON_BIT,
(void *) &cf_sk->flow_state);
}
static void set_tx_flow_on(struct caifsock *cf_sk)
{
set_bit(TX_FLOW_ON_BIT,
(void *) &cf_sk->flow_state);
}
static void caif_read_lock(struct sock *sk)
{
struct caifsock *cf_sk;
cf_sk = container_of(sk, struct caifsock, sk);
mutex_lock(&cf_sk->readlock);
}
static void caif_read_unlock(struct sock *sk)
{
struct caifsock *cf_sk;
cf_sk = container_of(sk, struct caifsock, sk);
mutex_unlock(&cf_sk->readlock);
}
static int sk_rcvbuf_lowwater(struct caifsock *cf_sk)
{
/* A quarter of full buffer is used a low water mark */
return cf_sk->sk.sk_rcvbuf / 4;
}
static void caif_flow_ctrl(struct sock *sk, int mode)
{
struct caifsock *cf_sk;
cf_sk = container_of(sk, struct caifsock, sk);
if (cf_sk->layer.dn && cf_sk->layer.dn->modemcmd)
cf_sk->layer.dn->modemcmd(cf_sk->layer.dn, mode);
}
/*
* Copied from sock.c:sock_queue_rcv_skb(), but changed so packets are
* not dropped, but CAIF is sending flow off instead.
*/
static int caif_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
int err;
int skb_len;
unsigned long flags;
struct sk_buff_head *list = &sk->sk_receive_queue;
struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
(unsigned int)sk->sk_rcvbuf && rx_flow_is_on(cf_sk)) {
net_dbg_ratelimited("sending flow OFF (queue len = %d %d)\n",
atomic_read(&cf_sk->sk.sk_rmem_alloc),
sk_rcvbuf_lowwater(cf_sk));
set_rx_flow_off(cf_sk);
caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
}
err = sk_filter(sk, skb);
if (err)
return err;
if (!sk_rmem_schedule(sk, skb, skb->truesize) && rx_flow_is_on(cf_sk)) {
set_rx_flow_off(cf_sk);
net_dbg_ratelimited("sending flow OFF due to rmem_schedule\n");
caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
}
skb->dev = NULL;
skb_set_owner_r(skb, sk);
/* Cache the SKB length before we tack it onto the receive
* queue. Once it is added it no longer belongs to us and
* may be freed by other threads of control pulling packets
* from the queue.
*/
skb_len = skb->len;
spin_lock_irqsave(&list->lock, flags);
if (!sock_flag(sk, SOCK_DEAD))
__skb_queue_tail(list, skb);
spin_unlock_irqrestore(&list->lock, flags);
if (!sock_flag(sk, SOCK_DEAD))
sk->sk_data_ready(sk, skb_len);
else
kfree_skb(skb);
return 0;
}
/* Packet Receive Callback function called from CAIF Stack */
static int caif_sktrecv_cb(struct cflayer *layr, struct cfpkt *pkt)
{
struct caifsock *cf_sk;
struct sk_buff *skb;
cf_sk = container_of(layr, struct caifsock, layer);
skb = cfpkt_tonative(pkt);
if (unlikely(cf_sk->sk.sk_state != CAIF_CONNECTED)) {
kfree_skb(skb);
return 0;
}
caif_queue_rcv_skb(&cf_sk->sk, skb);
return 0;
}
static void cfsk_hold(struct cflayer *layr)
{
struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
sock_hold(&cf_sk->sk);
}
static void cfsk_put(struct cflayer *layr)
{
struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
sock_put(&cf_sk->sk);
}
/* Packet Control Callback function called from CAIF */
static void caif_ctrl_cb(struct cflayer *layr,
enum caif_ctrlcmd flow,
int phyid)
{
struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
switch (flow) {
case CAIF_CTRLCMD_FLOW_ON_IND:
/* OK from modem to start sending again */
set_tx_flow_on(cf_sk);
cf_sk->sk.sk_state_change(&cf_sk->sk);
break;
case CAIF_CTRLCMD_FLOW_OFF_IND:
/* Modem asks us to shut up */
set_tx_flow_off(cf_sk);
cf_sk->sk.sk_state_change(&cf_sk->sk);
break;
case CAIF_CTRLCMD_INIT_RSP:
/* We're now connected */
caif_client_register_refcnt(&cf_sk->layer,
cfsk_hold, cfsk_put);
cf_sk->sk.sk_state = CAIF_CONNECTED;
set_tx_flow_on(cf_sk);
cf_sk->sk.sk_shutdown = 0;
cf_sk->sk.sk_state_change(&cf_sk->sk);
break;
case CAIF_CTRLCMD_DEINIT_RSP:
/* We're now disconnected */
cf_sk->sk.sk_state = CAIF_DISCONNECTED;
cf_sk->sk.sk_state_change(&cf_sk->sk);
break;
case CAIF_CTRLCMD_INIT_FAIL_RSP:
/* Connect request failed */
cf_sk->sk.sk_err = ECONNREFUSED;
cf_sk->sk.sk_state = CAIF_DISCONNECTED;
cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
/*
* Socket "standards" seems to require POLLOUT to
* be set at connect failure.
*/
set_tx_flow_on(cf_sk);
cf_sk->sk.sk_state_change(&cf_sk->sk);
break;
case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
/* Modem has closed this connection, or device is down. */
cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
cf_sk->sk.sk_err = ECONNRESET;
set_rx_flow_on(cf_sk);
cf_sk->sk.sk_error_report(&cf_sk->sk);
break;
default:
pr_debug("Unexpected flow command %d\n", flow);
}
}
static void caif_check_flow_release(struct sock *sk)
{
struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
if (rx_flow_is_on(cf_sk))
return;
if (atomic_read(&sk->sk_rmem_alloc) <= sk_rcvbuf_lowwater(cf_sk)) {
set_rx_flow_on(cf_sk);
caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_ON_REQ);
}
}
/*
* Copied from unix_dgram_recvmsg, but removed credit checks,
* changed locking, address handling and added MSG_TRUNC.
*/
static int caif_seqpkt_recvmsg(struct kiocb *iocb, struct socket *sock,
struct msghdr *m, size_t len, int flags)
{
struct sock *sk = sock->sk;
struct sk_buff *skb;
int ret;
int copylen;
ret = -EOPNOTSUPP;
if (m->msg_flags&MSG_OOB)
goto read_error;
skb = skb_recv_datagram(sk, flags, 0 , &ret);
if (!skb)
goto read_error;
copylen = skb->len;
if (len < copylen) {
m->msg_flags |= MSG_TRUNC;
copylen = len;
}
ret = skb_copy_datagram_iovec(skb, 0, m->msg_iov, copylen);
if (ret)
goto out_free;
ret = (flags & MSG_TRUNC) ? skb->len : copylen;
out_free:
skb_free_datagram(sk, skb);
caif_check_flow_release(sk);
return ret;
read_error:
return ret;
}
/* Copied from unix_stream_wait_data, identical except for lock call. */
static long caif_stream_data_wait(struct sock *sk, long timeo)
{
DEFINE_WAIT(wait);
lock_sock(sk);
for (;;) {
prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
if (!skb_queue_empty(&sk->sk_receive_queue) ||
sk->sk_err ||
sk->sk_state != CAIF_CONNECTED ||
sock_flag(sk, SOCK_DEAD) ||
(sk->sk_shutdown & RCV_SHUTDOWN) ||
signal_pending(current) ||
!timeo)
break;
set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
release_sock(sk);
timeo = schedule_timeout(timeo);
lock_sock(sk);
clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
}
finish_wait(sk_sleep(sk), &wait);
release_sock(sk);
return timeo;
}
/*
* Copied from unix_stream_recvmsg, but removed credit checks,
* changed locking calls, changed address handling.
*/
static int caif_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
struct msghdr *msg, size_t size,
int flags)
{
struct sock *sk = sock->sk;
int copied = 0;
int target;
int err = 0;
long timeo;
err = -EOPNOTSUPP;
if (flags&MSG_OOB)
goto out;
msg->msg_namelen = 0;
/*
* Lock the socket to prevent queue disordering
* while sleeps in memcpy_tomsg
*/
err = -EAGAIN;
if (sk->sk_state == CAIF_CONNECTING)
goto out;
caif_read_lock(sk);
target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
do {
int chunk;
struct sk_buff *skb;
lock_sock(sk);
skb = skb_dequeue(&sk->sk_receive_queue);
caif_check_flow_release(sk);
if (skb == NULL) {
if (copied >= target)
goto unlock;
/*
* POSIX 1003.1g mandates this order.
*/
err = sock_error(sk);
if (err)
goto unlock;
err = -ECONNRESET;
if (sk->sk_shutdown & RCV_SHUTDOWN)
goto unlock;
err = -EPIPE;
if (sk->sk_state != CAIF_CONNECTED)
goto unlock;
if (sock_flag(sk, SOCK_DEAD))
goto unlock;
release_sock(sk);
err = -EAGAIN;
if (!timeo)
break;
caif_read_unlock(sk);
timeo = caif_stream_data_wait(sk, timeo);
if (signal_pending(current)) {
err = sock_intr_errno(timeo);
goto out;
}
caif_read_lock(sk);
continue;
unlock:
release_sock(sk);
break;
}
release_sock(sk);
chunk = min_t(unsigned int, skb->len, size);
if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
skb_queue_head(&sk->sk_receive_queue, skb);
if (copied == 0)
copied = -EFAULT;
break;
}
copied += chunk;
size -= chunk;
/* Mark read part of skb as used */
if (!(flags & MSG_PEEK)) {
skb_pull(skb, chunk);
/* put the skb back if we didn't use it up. */
if (skb->len) {
skb_queue_head(&sk->sk_receive_queue, skb);
break;
}
kfree_skb(skb);
} else {
/*
* It is questionable, see note in unix_dgram_recvmsg.
*/
/* put message back and return */
skb_queue_head(&sk->sk_receive_queue, skb);
break;
}
} while (size);
caif_read_unlock(sk);
out:
return copied ? : err;
}
/*
* Copied from sock.c:sock_wait_for_wmem, but change to wait for
* CAIF flow-on and sock_writable.
*/
static long caif_wait_for_flow_on(struct caifsock *cf_sk,
int wait_writeable, long timeo, int *err)
{
struct sock *sk = &cf_sk->sk;
DEFINE_WAIT(wait);
for (;;) {
*err = 0;
if (tx_flow_is_on(cf_sk) &&
(!wait_writeable || sock_writeable(&cf_sk->sk)))
break;
*err = -ETIMEDOUT;
if (!timeo)
break;
*err = -ERESTARTSYS;
if (signal_pending(current))
break;
prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
*err = -ECONNRESET;
if (sk->sk_shutdown & SHUTDOWN_MASK)
break;
*err = -sk->sk_err;
if (sk->sk_err)
break;
*err = -EPIPE;
if (cf_sk->sk.sk_state != CAIF_CONNECTED)
break;
timeo = schedule_timeout(timeo);
}
finish_wait(sk_sleep(sk), &wait);
return timeo;
}
/*
* Transmit a SKB. The device may temporarily request re-transmission
* by returning EAGAIN.
*/
static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk,
int noblock, long timeo)
{
struct cfpkt *pkt;
pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
memset(skb->cb, 0, sizeof(struct caif_payload_info));
cfpkt_set_prio(pkt, cf_sk->sk.sk_priority);
if (cf_sk->layer.dn == NULL) {
kfree_skb(skb);
return -EINVAL;
}
return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
}
/* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */
static int caif_seqpkt_sendmsg(struct kiocb *kiocb, struct socket *sock,
struct msghdr *msg, size_t len)
{
struct sock *sk = sock->sk;
struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
int buffer_size;
int ret = 0;
struct sk_buff *skb = NULL;
int noblock;
long timeo;
caif_assert(cf_sk);
ret = sock_error(sk);
if (ret)
goto err;
ret = -EOPNOTSUPP;
if (msg->msg_flags&MSG_OOB)
goto err;
ret = -EOPNOTSUPP;
if (msg->msg_namelen)
goto err;
ret = -EINVAL;
if (unlikely(msg->msg_iov->iov_base == NULL))
goto err;
noblock = msg->msg_flags & MSG_DONTWAIT;
timeo = sock_sndtimeo(sk, noblock);
timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
1, timeo, &ret);
if (ret)
goto err;
ret = -EPIPE;
if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
sock_flag(sk, SOCK_DEAD) ||
(sk->sk_shutdown & RCV_SHUTDOWN))
goto err;
/* Error if trying to write more than maximum frame size. */
ret = -EMSGSIZE;
if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM)
goto err;
buffer_size = len + cf_sk->headroom + cf_sk->tailroom;
ret = -ENOMEM;
skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret);
if (!skb || skb_tailroom(skb) < buffer_size)
goto err;
skb_reserve(skb, cf_sk->headroom);
ret = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
if (ret)
goto err;
ret = transmit_skb(skb, cf_sk, noblock, timeo);
if (ret < 0)
/* skb is already freed */
return ret;
return len;
err:
kfree_skb(skb);
return ret;
}
/*
* Copied from unix_stream_sendmsg and adapted to CAIF:
* Changed removed permission handling and added waiting for flow on
* and other minor adaptations.
*/
static int caif_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
struct msghdr *msg, size_t len)
{
struct sock *sk = sock->sk;
struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
int err, size;
struct sk_buff *skb;
int sent = 0;
long timeo;
err = -EOPNOTSUPP;
if (unlikely(msg->msg_flags&MSG_OOB))
goto out_err;
if (unlikely(msg->msg_namelen))
goto out_err;
timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err);
if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
goto pipe_err;
while (sent < len) {
size = len-sent;
if (size > cf_sk->maxframe)
size = cf_sk->maxframe;
/* If size is more than half of sndbuf, chop up message */
if (size > ((sk->sk_sndbuf >> 1) - 64))
size = (sk->sk_sndbuf >> 1) - 64;
if (size > SKB_MAX_ALLOC)
size = SKB_MAX_ALLOC;
skb = sock_alloc_send_skb(sk,
size + cf_sk->headroom +
cf_sk->tailroom,
msg->msg_flags&MSG_DONTWAIT,
&err);
if (skb == NULL)
goto out_err;
skb_reserve(skb, cf_sk->headroom);
/*
* If you pass two values to the sock_alloc_send_skb
* it tries to grab the large buffer with GFP_NOFS
* (which can fail easily), and if it fails grab the
* fallback size buffer which is under a page and will
* succeed. [Alan]
*/
size = min_t(int, size, skb_tailroom(skb));
err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
if (err) {
kfree_skb(skb);
goto out_err;
}
err = transmit_skb(skb, cf_sk,
msg->msg_flags&MSG_DONTWAIT, timeo);
if (err < 0)
/* skb is already freed */
goto pipe_err;
sent += size;
}
return sent;
pipe_err:
if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
send_sig(SIGPIPE, current, 0);
err = -EPIPE;
out_err:
return sent ? : err;
}
static int setsockopt(struct socket *sock,
int lvl, int opt, char __user *ov, unsigned int ol)
{
struct sock *sk = sock->sk;
struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
int linksel;
if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED)
return -ENOPROTOOPT;
switch (opt) {
case CAIFSO_LINK_SELECT:
if (ol < sizeof(int))
return -EINVAL;
if (lvl != SOL_CAIF)
goto bad_sol;
if (copy_from_user(&linksel, ov, sizeof(int)))
return -EINVAL;
lock_sock(&(cf_sk->sk));
cf_sk->conn_req.link_selector = linksel;
release_sock(&cf_sk->sk);
return 0;
case CAIFSO_REQ_PARAM:
if (lvl != SOL_CAIF)
goto bad_sol;
if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL)
return -ENOPROTOOPT;
lock_sock(&(cf_sk->sk));
if (ol > sizeof(cf_sk->conn_req.param.data) ||
copy_from_user(&cf_sk->conn_req.param.data, ov, ol)) {
release_sock(&cf_sk->sk);
return -EINVAL;
}
cf_sk->conn_req.param.size = ol;
release_sock(&cf_sk->sk);
return 0;
default:
return -ENOPROTOOPT;
}
return 0;
bad_sol:
return -ENOPROTOOPT;
}
/*
* caif_connect() - Connect a CAIF Socket
* Copied and modified af_irda.c:irda_connect().
*
* Note : by consulting "errno", the user space caller may learn the cause
* of the failure. Most of them are visible in the function, others may come
* from subroutines called and are listed here :
* o -EAFNOSUPPORT: bad socket family or type.
* o -ESOCKTNOSUPPORT: bad socket type or protocol
* o -EINVAL: bad socket address, or CAIF link type
* o -ECONNREFUSED: remote end refused the connection.
* o -EINPROGRESS: connect request sent but timed out (or non-blocking)
* o -EISCONN: already connected.
* o -ETIMEDOUT: Connection timed out (send timeout)
* o -ENODEV: No link layer to send request
* o -ECONNRESET: Received Shutdown indication or lost link layer
* o -ENOMEM: Out of memory
*
* State Strategy:
* o sk_state: holds the CAIF_* protocol state, it's updated by
* caif_ctrl_cb.
* o sock->state: holds the SS_* socket state and is updated by connect and
* disconnect.
*/
static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
int addr_len, int flags)
{
struct sock *sk = sock->sk;
struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
long timeo;
int err;
int ifindex, headroom, tailroom;
unsigned int mtu;
struct net_device *dev;
lock_sock(sk);
err = -EAFNOSUPPORT;
if (uaddr->sa_family != AF_CAIF)
goto out;
switch (sock->state) {
case SS_UNCONNECTED:
/* Normal case, a fresh connect */
caif_assert(sk->sk_state == CAIF_DISCONNECTED);
break;
case SS_CONNECTING:
switch (sk->sk_state) {
case CAIF_CONNECTED:
sock->state = SS_CONNECTED;
err = -EISCONN;
goto out;
case CAIF_DISCONNECTED:
/* Reconnect allowed */
break;
case CAIF_CONNECTING:
err = -EALREADY;
if (flags & O_NONBLOCK)
goto out;
goto wait_connect;
}
break;
case SS_CONNECTED:
caif_assert(sk->sk_state == CAIF_CONNECTED ||
sk->sk_state == CAIF_DISCONNECTED);
if (sk->sk_shutdown & SHUTDOWN_MASK) {
/* Allow re-connect after SHUTDOWN_IND */
caif_disconnect_client(sock_net(sk), &cf_sk->layer);
caif_free_client(&cf_sk->layer);
break;
}
/* No reconnect on a seqpacket socket */
err = -EISCONN;
goto out;
case SS_DISCONNECTING:
case SS_FREE:
caif_assert(1); /*Should never happen */
break;
}
sk->sk_state = CAIF_DISCONNECTED;
sock->state = SS_UNCONNECTED;
sk_stream_kill_queues(&cf_sk->sk);
err = -EINVAL;
if (addr_len != sizeof(struct sockaddr_caif))
goto out;
memcpy(&cf_sk->conn_req.sockaddr, uaddr,
sizeof(struct sockaddr_caif));
/* Move to connecting socket, start sending Connect Requests */
sock->state = SS_CONNECTING;
sk->sk_state = CAIF_CONNECTING;
/* Check priority value comming from socket */
/* if priority value is out of range it will be ajusted */
if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
cf_sk->conn_req.priority = CAIF_PRIO_MAX;
else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN)
cf_sk->conn_req.priority = CAIF_PRIO_MIN;
else
cf_sk->conn_req.priority = cf_sk->sk.sk_priority;
/*ifindex = id of the interface.*/
cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if;
cf_sk->layer.receive = caif_sktrecv_cb;
err = caif_connect_client(sock_net(sk), &cf_sk->conn_req,
&cf_sk->layer, &ifindex, &headroom, &tailroom);
if (err < 0) {
cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
cf_sk->sk.sk_state = CAIF_DISCONNECTED;
goto out;
}
err = -ENODEV;
rcu_read_lock();
dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
if (!dev) {
rcu_read_unlock();
goto out;
}
cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom);
mtu = dev->mtu;
rcu_read_unlock();
cf_sk->tailroom = tailroom;
cf_sk->maxframe = mtu - (headroom + tailroom);
if (cf_sk->maxframe < 1) {
pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu);
err = -ENODEV;
goto out;
}
err = -EINPROGRESS;
wait_connect:
if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK))
goto out;
timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
release_sock(sk);
err = -ERESTARTSYS;
timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
sk->sk_state != CAIF_CONNECTING,
timeo);
lock_sock(sk);
if (timeo < 0)
goto out; /* -ERESTARTSYS */
err = -ETIMEDOUT;
if (timeo == 0 && sk->sk_state != CAIF_CONNECTED)
goto out;
if (sk->sk_state != CAIF_CONNECTED) {
sock->state = SS_UNCONNECTED;
err = sock_error(sk);
if (!err)
err = -ECONNREFUSED;
goto out;
}
sock->state = SS_CONNECTED;
err = 0;
out:
release_sock(sk);
return err;
}
/*
* caif_release() - Disconnect a CAIF Socket
* Copied and modified af_irda.c:irda_release().
*/
static int caif_release(struct socket *sock)
{
struct sock *sk = sock->sk;
struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
if (!sk)
return 0;
set_tx_flow_off(cf_sk);
/*
* Ensure that packets are not queued after this point in time.
* caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock,
* this ensures no packets when sock is dead.
*/
spin_lock_bh(&sk->sk_receive_queue.lock);
sock_set_flag(sk, SOCK_DEAD);
spin_unlock_bh(&sk->sk_receive_queue.lock);
sock->sk = NULL;
WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir));
if (cf_sk->debugfs_socket_dir != NULL)
debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
lock_sock(&(cf_sk->sk));
sk->sk_state = CAIF_DISCONNECTED;
sk->sk_shutdown = SHUTDOWN_MASK;
caif_disconnect_client(sock_net(sk), &cf_sk->layer);
cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
wake_up_interruptible_poll(sk_sleep(sk), POLLERR|POLLHUP);
sock_orphan(sk);
sk_stream_kill_queues(&cf_sk->sk);
release_sock(sk);
sock_put(sk);
return 0;
}
/* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */
static unsigned int caif_poll(struct file *file,
struct socket *sock, poll_table *wait)
{
struct sock *sk = sock->sk;
unsigned int mask;
struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
sock_poll_wait(file, sk_sleep(sk), wait);
mask = 0;
/* exceptional events? */
if (sk->sk_err)
mask |= POLLERR;
if (sk->sk_shutdown == SHUTDOWN_MASK)
mask |= POLLHUP;
if (sk->sk_shutdown & RCV_SHUTDOWN)
mask |= POLLRDHUP;
/* readable? */
if (!skb_queue_empty(&sk->sk_receive_queue) ||
(sk->sk_shutdown & RCV_SHUTDOWN))
mask |= POLLIN | POLLRDNORM;
/*
* we set writable also when the other side has shut down the
* connection. This prevents stuck sockets.
*/
if (sock_writeable(sk) && tx_flow_is_on(cf_sk))
mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
return mask;
}
static const struct proto_ops caif_seqpacket_ops = {
.family = PF_CAIF,
.owner = THIS_MODULE,
.release = caif_release,
.bind = sock_no_bind,
.connect = caif_connect,
.socketpair = sock_no_socketpair,
.accept = sock_no_accept,
.getname = sock_no_getname,
.poll = caif_poll,
.ioctl = sock_no_ioctl,
.listen = sock_no_listen,
.shutdown = sock_no_shutdown,
.setsockopt = setsockopt,
.getsockopt = sock_no_getsockopt,
.sendmsg = caif_seqpkt_sendmsg,
.recvmsg = caif_seqpkt_recvmsg,
.mmap = sock_no_mmap,
.sendpage = sock_no_sendpage,
};
static const struct proto_ops caif_stream_ops = {
.family = PF_CAIF,
.owner = THIS_MODULE,
.release = caif_release,
.bind = sock_no_bind,
.connect = caif_connect,
.socketpair = sock_no_socketpair,
.accept = sock_no_accept,
.getname = sock_no_getname,
.poll = caif_poll,
.ioctl = sock_no_ioctl,
.listen = sock_no_listen,
.shutdown = sock_no_shutdown,
.setsockopt = setsockopt,
.getsockopt = sock_no_getsockopt,
.sendmsg = caif_stream_sendmsg,
.recvmsg = caif_stream_recvmsg,
.mmap = sock_no_mmap,
.sendpage = sock_no_sendpage,
};
/* This function is called when a socket is finally destroyed. */
static void caif_sock_destructor(struct sock *sk)
{
struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
caif_assert(!atomic_read(&sk->sk_wmem_alloc));
caif_assert(sk_unhashed(sk));
caif_assert(!sk->sk_socket);
if (!sock_flag(sk, SOCK_DEAD)) {
pr_debug("Attempt to release alive CAIF socket: %p\n", sk);
return;
}
sk_stream_kill_queues(&cf_sk->sk);
caif_free_client(&cf_sk->layer);
}
static int caif_create(struct net *net, struct socket *sock, int protocol,
int kern)
{
struct sock *sk = NULL;
struct caifsock *cf_sk = NULL;
static struct proto prot = {.name = "PF_CAIF",
.owner = THIS_MODULE,
.obj_size = sizeof(struct caifsock),
};
if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
return -EPERM;
/*
* The sock->type specifies the socket type to use.
* The CAIF socket is a packet stream in the sense
* that it is packet based. CAIF trusts the reliability
* of the link, no resending is implemented.
*/
if (sock->type == SOCK_SEQPACKET)
sock->ops = &caif_seqpacket_ops;
else if (sock->type == SOCK_STREAM)
sock->ops = &caif_stream_ops;
else
return -ESOCKTNOSUPPORT;
if (protocol < 0 || protocol >= CAIFPROTO_MAX)
return -EPROTONOSUPPORT;
/*
* Set the socket state to unconnected. The socket state
* is really not used at all in the net/core or socket.c but the
* initialization makes sure that sock->state is not uninitialized.
*/
sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot);
if (!sk)
return -ENOMEM;
cf_sk = container_of(sk, struct caifsock, sk);
/* Store the protocol */
sk->sk_protocol = (unsigned char) protocol;
/* Initialize default priority for well-known cases */
switch (protocol) {
case CAIFPROTO_AT:
sk->sk_priority = TC_PRIO_CONTROL;
break;
case CAIFPROTO_RFM:
sk->sk_priority = TC_PRIO_INTERACTIVE_BULK;
break;
default:
sk->sk_priority = TC_PRIO_BESTEFFORT;
}
/*
* Lock in order to try to stop someone from opening the socket
* too early.
*/
lock_sock(&(cf_sk->sk));
/* Initialize the nozero default sock structure data. */
sock_init_data(sock, sk);
sk->sk_destruct = caif_sock_destructor;
mutex_init(&cf_sk->readlock); /* single task reading lock */
cf_sk->layer.ctrlcmd = caif_ctrl_cb;
cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
cf_sk->sk.sk_state = CAIF_DISCONNECTED;
set_tx_flow_off(cf_sk);
set_rx_flow_on(cf_sk);
/* Set default options on configuration */
cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY;
cf_sk->conn_req.protocol = protocol;
release_sock(&cf_sk->sk);
return 0;
}
static struct net_proto_family caif_family_ops = {
.family = PF_CAIF,
.create = caif_create,
.owner = THIS_MODULE,
};
static int __init caif_sktinit_module(void)
{
int err = sock_register(&caif_family_ops);
if (!err)
return err;
return 0;
}
static void __exit caif_sktexit_module(void)
{
sock_unregister(PF_CAIF);
}
module_init(caif_sktinit_module);
module_exit(caif_sktexit_module);
Reference in a new issue View git blame Copy permalink