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Copy pathcaif_socket.c
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caif_socket.c
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/*
* Copyright (C) ST-Ericsson AB 2010
* Author: Sjur Brendeland sjur.brandeland@stericsson.com
* License terms: GNU General Public License (GPL) version 2
*/
#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/mutex.h>
#include <linux/debugfs.h>
#include <linux/caif/caif_socket.h>
#include <asm/atomic.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);
#define CAIF_DEF_SNDBUF (CAIF_MAX_PAYLOAD_SIZE*10)
#define CAIF_DEF_RCVBUF (CAIF_MAX_PAYLOAD_SIZE*100)
/*
* 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
static struct dentry *debugfsdir;
#ifdef CONFIG_DEBUG_FS
struct debug_fs_counter {
atomic_t caif_nr_socks;
atomic_t num_connect_req;
atomic_t num_connect_resp;
atomic_t num_connect_fail_resp;
atomic_t num_disconnect;
atomic_t num_remote_shutdown_ind;
atomic_t num_tx_flow_off_ind;
atomic_t num_tx_flow_on_ind;
atomic_t num_rx_flow_off;
atomic_t num_rx_flow_on;
};
static struct debug_fs_counter cnt;
#define dbfs_atomic_inc(v) atomic_inc(v)
#define dbfs_atomic_dec(v) atomic_dec(v)
#else
#define dbfs_atomic_inc(v)
#define dbfs_atomic_dec(v)
#endif
struct caifsock {
struct sock sk; /* must be first member */
struct cflayer layer;
char name[CAIF_LAYER_NAME_SZ]; /* Used for debugging */
u32 flow_state;
struct caif_connect_request conn_req;
struct mutex readlock;
struct dentry *debugfs_socket_dir;
};
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)sk->sk_rcvbuf && rx_flow_is_on(cf_sk)) {
trace_printk("CAIF: %s():"
" sending flow OFF (queue len = %d %d)\n",
__func__,
atomic_read(&cf_sk->sk.sk_rmem_alloc),
sk_rcvbuf_lowwater(cf_sk));
set_rx_flow_off(cf_sk);
dbfs_atomic_inc(&cnt.num_rx_flow_off);
caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
}
err = sk_filter(sk, skb);
if (err)
return err;
if (!sk_rmem_schedule(sk, skb->truesize) && rx_flow_is_on(cf_sk)) {
set_rx_flow_off(cf_sk);
trace_printk("CAIF: %s():"
" sending flow OFF due to rmem_schedule\n",
__func__);
dbfs_atomic_inc(&cnt.num_rx_flow_off);
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)) {
cfpkt_destroy(pkt);
return 0;
}
caif_queue_rcv_skb(&cf_sk->sk, skb);
return 0;
}
/* 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 */
dbfs_atomic_inc(&cnt.num_tx_flow_on_ind);
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 */
dbfs_atomic_inc(&cnt.num_tx_flow_off_ind);
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 */
dbfs_atomic_inc(&cnt.num_connect_resp);
cf_sk->sk.sk_state = CAIF_CONNECTED;
set_tx_flow_on(cf_sk);
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);
cfcnfg_release_adap_layer(&cf_sk->layer);
break;
case CAIF_CTRLCMD_INIT_FAIL_RSP:
/* Connect request failed */
dbfs_atomic_inc(&cnt.num_connect_fail_resp);
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. */
dbfs_atomic_inc(&cnt.num_remote_shutdown_ind);
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("CAIF: %s(): Unexpected flow command %d\n",
__func__, 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)) {
dbfs_atomic_inc(&cnt.num_rx_flow_on);
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;
int ret, loopcnt = 0;
pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
memset(cfpkt_info(pkt), 0, sizeof(struct caif_payload_info));
do {
ret = -ETIMEDOUT;
/* Slight paranoia, probably not needed. */
if (unlikely(loopcnt++ > 1000)) {
pr_warning("CAIF: %s(): transmit retries failed,"
" error = %d\n", __func__, ret);
break;
}
if (cf_sk->layer.dn != NULL)
ret = cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
if (likely(ret >= 0))
break;
/* if transmit return -EAGAIN, then retry */
if (noblock && ret == -EAGAIN)
break;
timeo = caif_wait_for_flow_on(cf_sk, 0, timeo, &ret);
if (signal_pending(current)) {
ret = sock_intr_errno(timeo);
break;
}
if (ret)
break;
if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
sock_flag(&cf_sk->sk, SOCK_DEAD) ||
(cf_sk->sk.sk_shutdown & RCV_SHUTDOWN)) {
ret = -EPIPE;
cf_sk->sk.sk_err = EPIPE;
break;
}
} while (ret == -EAGAIN);
return ret;
}
/* 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;
buffer_size = len + CAIF_NEEDED_HEADROOM + CAIF_NEEDED_TAILROOM;
ret = -EMSGSIZE;
if (buffer_size > CAIF_MAX_PAYLOAD_SIZE)
goto err;
timeo = sock_sndtimeo(sk, noblock);
timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
1, timeo, &ret);
ret = -EPIPE;
if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
sock_flag(sk, SOCK_DEAD) ||
(sk->sk_shutdown & RCV_SHUTDOWN))
goto err;
ret = -ENOMEM;
skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret);
if (!skb)
goto err;
skb_reserve(skb, CAIF_NEEDED_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)
goto err;
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 > CAIF_MAX_PAYLOAD_SIZE)
size = CAIF_MAX_PAYLOAD_SIZE;
/* 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 + CAIF_NEEDED_HEADROOM
+ CAIF_NEEDED_TAILROOM,
msg->msg_flags&MSG_DONTWAIT,
&err);
if (skb == NULL)
goto out_err;
skb_reserve(skb, CAIF_NEEDED_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) {
kfree_skb(skb);
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 prio, linksel;
struct ifreq ifreq;
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 SO_PRIORITY:
if (lvl != SOL_SOCKET)
goto bad_sol;
if (ol < sizeof(int))
return -EINVAL;
if (copy_from_user(&prio, ov, sizeof(int)))
return -EINVAL;
lock_sock(&(cf_sk->sk));
cf_sk->conn_req.priority = prio;
release_sock(&cf_sk->sk);
return 0;
case SO_BINDTODEVICE:
if (lvl != SOL_SOCKET)
goto bad_sol;
if (ol < sizeof(struct ifreq))
return -EINVAL;
if (copy_from_user(&ifreq, ov, sizeof(ifreq)))
return -EFAULT;
lock_sock(&(cf_sk->sk));
strncpy(cf_sk->conn_req.link_name, ifreq.ifr_name,
sizeof(cf_sk->conn_req.link_name));
cf_sk->conn_req.link_name
[sizeof(cf_sk->conn_req.link_name)-1] = 0;
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));
cf_sk->conn_req.param.size = ol;
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;
}
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;
lock_sock(sk);
err = -EAFNOSUPPORT;
if (uaddr->sa_family != AF_CAIF)
goto out;
err = -ESOCKTNOSUPPORT;
if (unlikely(!(sk->sk_type == SOCK_STREAM &&
cf_sk->sk.sk_protocol == CAIFPROTO_AT) &&
sk->sk_type != SOCK_SEQPACKET))
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(&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) ||
!uaddr)
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;
dbfs_atomic_inc(&cnt.num_connect_req);
cf_sk->layer.receive = caif_sktrecv_cb;
err = caif_connect_client(&cf_sk->conn_req,
&cf_sk->layer);
if (err < 0) {
cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
cf_sk->sk.sk_state = CAIF_DISCONNECTED;
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);
int res = 0;
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(&sk->sk_receive_queue.lock);
sock_set_flag(sk, SOCK_DEAD);
spin_unlock(&sk->sk_receive_queue.lock);
sock->sk = NULL;
dbfs_atomic_inc(&cnt.num_disconnect);
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;
if (cf_sk->sk.sk_socket->state == SS_CONNECTED ||
cf_sk->sk.sk_socket->state == SS_CONNECTING)
res = caif_disconnect_client(&cf_sk->layer);
cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
wake_up_interruptible_poll(sk_sleep(sk), POLLERR|POLLHUP);
sock_orphan(sk);
cf_sk->layer.dn = NULL;
sk_stream_kill_queues(&cf_sk->sk);
release_sock(sk);
sock_put(sk);
return res;
}
/* 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? */