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linux/net/phonet/pep.c
David Howells cdfbabfb2f net: Work around lockdep limitation in sockets that use sockets 
Lockdep issues a circular dependency warning when AFS issues an operation
through AF_RXRPC from a context in which the VFS/VM holds the mmap_sem.

The theory lockdep comes up with is as follows:

 (1) If the pagefault handler decides it needs to read pages from AFS, it
     calls AFS with mmap_sem held and AFS begins an AF_RXRPC call, but
     creating a call requires the socket lock:

	mmap_sem must be taken before sk_lock-AF_RXRPC

 (2) afs_open_socket() opens an AF_RXRPC socket and binds it.  rxrpc_bind()
     binds the underlying UDP socket whilst holding its socket lock.
     inet_bind() takes its own socket lock:

	sk_lock-AF_RXRPC must be taken before sk_lock-AF_INET

 (3) Reading from a TCP socket into a userspace buffer might cause a fault
     and thus cause the kernel to take the mmap_sem, but the TCP socket is
     locked whilst doing this:

	sk_lock-AF_INET must be taken before mmap_sem

However, lockdep's theory is wrong in this instance because it deals only
with lock classes and not individual locks.  The AF_INET lock in (2) isn't
really equivalent to the AF_INET lock in (3) as the former deals with a
socket entirely internal to the kernel that never sees userspace.  This is
a limitation in the design of lockdep.

Fix the general case by:

 (1) Double up all the locking keys used in sockets so that one set are
     used if the socket is created by userspace and the other set is used
     if the socket is created by the kernel.

 (2) Store the kern parameter passed to sk_alloc() in a variable in the
     sock struct (sk_kern_sock).  This informs sock_lock_init(),
     sock_init_data() and sk_clone_lock() as to the lock keys to be used.

     Note that the child created by sk_clone_lock() inherits the parent's
     kern setting.

 (3) Add a 'kern' parameter to ->accept() that is analogous to the one
     passed in to ->create() that distinguishes whether kernel_accept() or
     sys_accept4() was the caller and can be passed to sk_alloc().

     Note that a lot of accept functions merely dequeue an already
     allocated socket.  I haven't touched these as the new socket already
     exists before we get the parameter.

     Note also that there are a couple of places where I've made the accepted
     socket unconditionally kernel-based:

	irda_accept()
	rds_rcp_accept_one()
	tcp_accept_from_sock()

     because they follow a sock_create_kern() and accept off of that.

Whilst creating this, I noticed that lustre and ocfs don't create sockets
through sock_create_kern() and thus they aren't marked as for-kernel,
though they appear to be internal.  I wonder if these should do that so
that they use the new set of lock keys.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-09 18:23:27 -08:00

1376 lines
30 KiB
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/*
* File: pep.c
*
* Phonet pipe protocol end point socket
*
* Copyright (C) 2008 Nokia Corporation.
*
* Author: Rémi Denis-Courmont
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*/
#include <linux/kernel.h>
#include <linux/sched/signal.h>
#include <linux/slab.h>
#include <linux/socket.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <asm/ioctls.h>
#include <linux/phonet.h>
#include <linux/module.h>
#include <net/phonet/phonet.h>
#include <net/phonet/pep.h>
#include <net/phonet/gprs.h>
/* sk_state values:
* TCP_CLOSE sock not in use yet
* TCP_CLOSE_WAIT disconnected pipe
* TCP_LISTEN listening pipe endpoint
* TCP_SYN_RECV connected pipe in disabled state
* TCP_ESTABLISHED connected pipe in enabled state
*
* pep_sock locking:
* - sk_state, hlist: sock lock needed
* - listener: read only
* - pipe_handle: read only
*/
#define CREDITS_MAX 10
#define CREDITS_THR 7
#define pep_sb_size(s) (((s) + 5) & ~3) /* 2-bytes head, 32-bits aligned */
/* Get the next TLV sub-block. */
static unsigned char *pep_get_sb(struct sk_buff *skb, u8 *ptype, u8 *plen,
void *buf)
{
void *data = NULL;
struct {
u8 sb_type;
u8 sb_len;
} *ph, h;
int buflen = *plen;
ph = skb_header_pointer(skb, 0, 2, &h);
if (ph == NULL || ph->sb_len < 2 || !pskb_may_pull(skb, ph->sb_len))
return NULL;
ph->sb_len -= 2;
*ptype = ph->sb_type;
*plen = ph->sb_len;
if (buflen > ph->sb_len)
buflen = ph->sb_len;
data = skb_header_pointer(skb, 2, buflen, buf);
__skb_pull(skb, 2 + ph->sb_len);
return data;
}
static struct sk_buff *pep_alloc_skb(struct sock *sk, const void *payload,
int len, gfp_t priority)
{
struct sk_buff *skb = alloc_skb(MAX_PNPIPE_HEADER + len, priority);
if (!skb)
return NULL;
skb_set_owner_w(skb, sk);
skb_reserve(skb, MAX_PNPIPE_HEADER);
__skb_put(skb, len);
skb_copy_to_linear_data(skb, payload, len);
__skb_push(skb, sizeof(struct pnpipehdr));
skb_reset_transport_header(skb);
return skb;
}
static int pep_reply(struct sock *sk, struct sk_buff *oskb, u8 code,
const void *data, int len, gfp_t priority)
{
const struct pnpipehdr *oph = pnp_hdr(oskb);
struct pnpipehdr *ph;
struct sk_buff *skb;
struct sockaddr_pn peer;
skb = pep_alloc_skb(sk, data, len, priority);
if (!skb)
return -ENOMEM;
ph = pnp_hdr(skb);
ph->utid = oph->utid;
ph->message_id = oph->message_id + 1; /* REQ -> RESP */
ph->pipe_handle = oph->pipe_handle;
ph->error_code = code;
pn_skb_get_src_sockaddr(oskb, &peer);
return pn_skb_send(sk, skb, &peer);
}
static int pep_indicate(struct sock *sk, u8 id, u8 code,
const void *data, int len, gfp_t priority)
{
struct pep_sock *pn = pep_sk(sk);
struct pnpipehdr *ph;
struct sk_buff *skb;
skb = pep_alloc_skb(sk, data, len, priority);
if (!skb)
return -ENOMEM;
ph = pnp_hdr(skb);
ph->utid = 0;
ph->message_id = id;
ph->pipe_handle = pn->pipe_handle;
ph->data[0] = code;
return pn_skb_send(sk, skb, NULL);
}
#define PAD 0x00
static int pipe_handler_request(struct sock *sk, u8 id, u8 code,
const void *data, int len)
{
struct pep_sock *pn = pep_sk(sk);
struct pnpipehdr *ph;
struct sk_buff *skb;
skb = pep_alloc_skb(sk, data, len, GFP_KERNEL);
if (!skb)
return -ENOMEM;
ph = pnp_hdr(skb);
ph->utid = id; /* whatever */
ph->message_id = id;
ph->pipe_handle = pn->pipe_handle;
ph->data[0] = code;
return pn_skb_send(sk, skb, NULL);
}
static int pipe_handler_send_created_ind(struct sock *sk)
{
struct pep_sock *pn = pep_sk(sk);
u8 data[4] = {
PN_PIPE_SB_NEGOTIATED_FC, pep_sb_size(2),
pn->tx_fc, pn->rx_fc,
};
return pep_indicate(sk, PNS_PIPE_CREATED_IND, 1 /* sub-blocks */,
data, 4, GFP_ATOMIC);
}
static int pep_accept_conn(struct sock *sk, struct sk_buff *skb)
{
static const u8 data[20] = {
PAD, PAD, PAD, 2 /* sub-blocks */,
PN_PIPE_SB_REQUIRED_FC_TX, pep_sb_size(5), 3, PAD,
PN_MULTI_CREDIT_FLOW_CONTROL,
PN_ONE_CREDIT_FLOW_CONTROL,
PN_LEGACY_FLOW_CONTROL,
PAD,
PN_PIPE_SB_PREFERRED_FC_RX, pep_sb_size(5), 3, PAD,
PN_MULTI_CREDIT_FLOW_CONTROL,
PN_ONE_CREDIT_FLOW_CONTROL,
PN_LEGACY_FLOW_CONTROL,
PAD,
};
might_sleep();
return pep_reply(sk, skb, PN_PIPE_NO_ERROR, data, sizeof(data),
GFP_KERNEL);
}
static int pep_reject_conn(struct sock *sk, struct sk_buff *skb, u8 code,
gfp_t priority)
{
static const u8 data[4] = { PAD, PAD, PAD, 0 /* sub-blocks */ };
WARN_ON(code == PN_PIPE_NO_ERROR);
return pep_reply(sk, skb, code, data, sizeof(data), priority);
}
/* Control requests are not sent by the pipe service and have a specific
* message format. */
static int pep_ctrlreq_error(struct sock *sk, struct sk_buff *oskb, u8 code,
gfp_t priority)
{
const struct pnpipehdr *oph = pnp_hdr(oskb);
struct sk_buff *skb;
struct pnpipehdr *ph;
struct sockaddr_pn dst;
u8 data[4] = {
oph->data[0], /* PEP type */
code, /* error code, at an unusual offset */
PAD, PAD,
};
skb = pep_alloc_skb(sk, data, 4, priority);
if (!skb)
return -ENOMEM;
ph = pnp_hdr(skb);
ph->utid = oph->utid;
ph->message_id = PNS_PEP_CTRL_RESP;
ph->pipe_handle = oph->pipe_handle;
ph->data[0] = oph->data[1]; /* CTRL id */
pn_skb_get_src_sockaddr(oskb, &dst);
return pn_skb_send(sk, skb, &dst);
}
static int pipe_snd_status(struct sock *sk, u8 type, u8 status, gfp_t priority)
{
u8 data[4] = { type, PAD, PAD, status };
return pep_indicate(sk, PNS_PEP_STATUS_IND, PN_PEP_TYPE_COMMON,
data, 4, priority);
}
/* Send our RX flow control information to the sender.
* Socket must be locked. */
static void pipe_grant_credits(struct sock *sk, gfp_t priority)
{
struct pep_sock *pn = pep_sk(sk);
BUG_ON(sk->sk_state != TCP_ESTABLISHED);
switch (pn->rx_fc) {
case PN_LEGACY_FLOW_CONTROL: /* TODO */
break;
case PN_ONE_CREDIT_FLOW_CONTROL:
if (pipe_snd_status(sk, PN_PEP_IND_FLOW_CONTROL,
PEP_IND_READY, priority) == 0)
pn->rx_credits = 1;
break;
case PN_MULTI_CREDIT_FLOW_CONTROL:
if ((pn->rx_credits + CREDITS_THR) > CREDITS_MAX)
break;
if (pipe_snd_status(sk, PN_PEP_IND_ID_MCFC_GRANT_CREDITS,
CREDITS_MAX - pn->rx_credits,
priority) == 0)
pn->rx_credits = CREDITS_MAX;
break;
}
}
static int pipe_rcv_status(struct sock *sk, struct sk_buff *skb)
{
struct pep_sock *pn = pep_sk(sk);
struct pnpipehdr *hdr;
int wake = 0;
if (!pskb_may_pull(skb, sizeof(*hdr) + 4))
return -EINVAL;
hdr = pnp_hdr(skb);
if (hdr->data[0] != PN_PEP_TYPE_COMMON) {
net_dbg_ratelimited("Phonet unknown PEP type: %u\n",
(unsigned int)hdr->data[0]);
return -EOPNOTSUPP;
}
switch (hdr->data[1]) {
case PN_PEP_IND_FLOW_CONTROL:
switch (pn->tx_fc) {
case PN_LEGACY_FLOW_CONTROL:
switch (hdr->data[4]) {
case PEP_IND_BUSY:
atomic_set(&pn->tx_credits, 0);
break;
case PEP_IND_READY:
atomic_set(&pn->tx_credits, wake = 1);
break;
}
break;
case PN_ONE_CREDIT_FLOW_CONTROL:
if (hdr->data[4] == PEP_IND_READY)
atomic_set(&pn->tx_credits, wake = 1);
break;
}
break;
case PN_PEP_IND_ID_MCFC_GRANT_CREDITS:
if (pn->tx_fc != PN_MULTI_CREDIT_FLOW_CONTROL)
break;
atomic_add(wake = hdr->data[4], &pn->tx_credits);
break;
default:
net_dbg_ratelimited("Phonet unknown PEP indication: %u\n",
(unsigned int)hdr->data[1]);
return -EOPNOTSUPP;
}
if (wake)
sk->sk_write_space(sk);
return 0;
}
static int pipe_rcv_created(struct sock *sk, struct sk_buff *skb)
{
struct pep_sock *pn = pep_sk(sk);
struct pnpipehdr *hdr = pnp_hdr(skb);
u8 n_sb = hdr->data[0];
pn->rx_fc = pn->tx_fc = PN_LEGACY_FLOW_CONTROL;
__skb_pull(skb, sizeof(*hdr));
while (n_sb > 0) {
u8 type, buf[2], len = sizeof(buf);
u8 *data = pep_get_sb(skb, &type, &len, buf);
if (data == NULL)
return -EINVAL;
switch (type) {
case PN_PIPE_SB_NEGOTIATED_FC:
if (len < 2 || (data[0] | data[1]) > 3)
break;
pn->tx_fc = data[0] & 3;
pn->rx_fc = data[1] & 3;
break;
}
n_sb--;
}
return 0;
}
/* Queue an skb to a connected sock.
* Socket lock must be held. */
static int pipe_do_rcv(struct sock *sk, struct sk_buff *skb)
{
struct pep_sock *pn = pep_sk(sk);
struct pnpipehdr *hdr = pnp_hdr(skb);
struct sk_buff_head *queue;
int err = 0;
BUG_ON(sk->sk_state == TCP_CLOSE_WAIT);
switch (hdr->message_id) {
case PNS_PEP_CONNECT_REQ:
pep_reject_conn(sk, skb, PN_PIPE_ERR_PEP_IN_USE, GFP_ATOMIC);
break;
case PNS_PEP_DISCONNECT_REQ:
pep_reply(sk, skb, PN_PIPE_NO_ERROR, NULL, 0, GFP_ATOMIC);
sk->sk_state = TCP_CLOSE_WAIT;
if (!sock_flag(sk, SOCK_DEAD))
sk->sk_state_change(sk);
break;
case PNS_PEP_ENABLE_REQ:
/* Wait for PNS_PIPE_(ENABLED|REDIRECTED)_IND */
pep_reply(sk, skb, PN_PIPE_NO_ERROR, NULL, 0, GFP_ATOMIC);
break;
case PNS_PEP_RESET_REQ:
switch (hdr->state_after_reset) {
case PN_PIPE_DISABLE:
pn->init_enable = 0;
break;
case PN_PIPE_ENABLE:
pn->init_enable = 1;
break;
default: /* not allowed to send an error here!? */
err = -EINVAL;
goto out;
}
/* fall through */
case PNS_PEP_DISABLE_REQ:
atomic_set(&pn->tx_credits, 0);
pep_reply(sk, skb, PN_PIPE_NO_ERROR, NULL, 0, GFP_ATOMIC);
break;
case PNS_PEP_CTRL_REQ:
if (skb_queue_len(&pn->ctrlreq_queue) >= PNPIPE_CTRLREQ_MAX) {
atomic_inc(&sk->sk_drops);
break;
}
__skb_pull(skb, 4);
queue = &pn->ctrlreq_queue;
goto queue;
case PNS_PIPE_ALIGNED_DATA:
__skb_pull(skb, 1);
/* fall through */
case PNS_PIPE_DATA:
__skb_pull(skb, 3); /* Pipe data header */
if (!pn_flow_safe(pn->rx_fc)) {
err = sock_queue_rcv_skb(sk, skb);
if (!err)
return NET_RX_SUCCESS;
err = -ENOBUFS;
break;
}
if (pn->rx_credits == 0) {
atomic_inc(&sk->sk_drops);
err = -ENOBUFS;
break;
}
pn->rx_credits--;
queue = &sk->sk_receive_queue;
goto queue;
case PNS_PEP_STATUS_IND:
pipe_rcv_status(sk, skb);
break;
case PNS_PIPE_REDIRECTED_IND:
err = pipe_rcv_created(sk, skb);
break;
case PNS_PIPE_CREATED_IND:
err = pipe_rcv_created(sk, skb);
if (err)
break;
/* fall through */
case PNS_PIPE_RESET_IND:
if (!pn->init_enable)
break;
/* fall through */
case PNS_PIPE_ENABLED_IND:
if (!pn_flow_safe(pn->tx_fc)) {
atomic_set(&pn->tx_credits, 1);
sk->sk_write_space(sk);
}
if (sk->sk_state == TCP_ESTABLISHED)
break; /* Nothing to do */
sk->sk_state = TCP_ESTABLISHED;
pipe_grant_credits(sk, GFP_ATOMIC);
break;
case PNS_PIPE_DISABLED_IND:
sk->sk_state = TCP_SYN_RECV;
pn->rx_credits = 0;
break;
default:
net_dbg_ratelimited("Phonet unknown PEP message: %u\n",
hdr->message_id);
err = -EINVAL;
}
out:
kfree_skb(skb);
return (err == -ENOBUFS) ? NET_RX_DROP : NET_RX_SUCCESS;
queue:
skb->dev = NULL;
skb_set_owner_r(skb, sk);
skb_queue_tail(queue, skb);
if (!sock_flag(sk, SOCK_DEAD))
sk->sk_data_ready(sk);
return NET_RX_SUCCESS;
}
/* Destroy connected sock. */
static void pipe_destruct(struct sock *sk)
{
struct pep_sock *pn = pep_sk(sk);
skb_queue_purge(&sk->sk_receive_queue);
skb_queue_purge(&pn->ctrlreq_queue);
}
static u8 pipe_negotiate_fc(const u8 *fcs, unsigned int n)
{
unsigned int i;
u8 final_fc = PN_NO_FLOW_CONTROL;
for (i = 0; i < n; i++) {
u8 fc = fcs[i];
if (fc > final_fc && fc < PN_MAX_FLOW_CONTROL)
final_fc = fc;
}
return final_fc;
}
static int pep_connresp_rcv(struct sock *sk, struct sk_buff *skb)
{
struct pep_sock *pn = pep_sk(sk);
struct pnpipehdr *hdr;
u8 n_sb;
if (!pskb_pull(skb, sizeof(*hdr) + 4))
return -EINVAL;
hdr = pnp_hdr(skb);
if (hdr->error_code != PN_PIPE_NO_ERROR)
return -ECONNREFUSED;
/* Parse sub-blocks */
n_sb = hdr->data[4];
while (n_sb > 0) {
u8 type, buf[6], len = sizeof(buf);
const u8 *data = pep_get_sb(skb, &type, &len, buf);
if (data == NULL)
return -EINVAL;
switch (type) {
case PN_PIPE_SB_REQUIRED_FC_TX:
if (len < 2 || len < data[0])
break;
pn->tx_fc = pipe_negotiate_fc(data + 2, len - 2);
break;
case PN_PIPE_SB_PREFERRED_FC_RX:
if (len < 2 || len < data[0])
break;
pn->rx_fc = pipe_negotiate_fc(data + 2, len - 2);
break;
}
n_sb--;
}
return pipe_handler_send_created_ind(sk);
}
static int pep_enableresp_rcv(struct sock *sk, struct sk_buff *skb)
{
struct pnpipehdr *hdr = pnp_hdr(skb);
if (hdr->error_code != PN_PIPE_NO_ERROR)
return -ECONNREFUSED;
return pep_indicate(sk, PNS_PIPE_ENABLED_IND, 0 /* sub-blocks */,
NULL, 0, GFP_ATOMIC);
}
static void pipe_start_flow_control(struct sock *sk)
{
struct pep_sock *pn = pep_sk(sk);
if (!pn_flow_safe(pn->tx_fc)) {
atomic_set(&pn->tx_credits, 1);
sk->sk_write_space(sk);
}
pipe_grant_credits(sk, GFP_ATOMIC);
}
/* Queue an skb to an actively connected sock.
* Socket lock must be held. */
static int pipe_handler_do_rcv(struct sock *sk, struct sk_buff *skb)
{
struct pep_sock *pn = pep_sk(sk);
struct pnpipehdr *hdr = pnp_hdr(skb);
int err = NET_RX_SUCCESS;
switch (hdr->message_id) {
case PNS_PIPE_ALIGNED_DATA:
__skb_pull(skb, 1);
/* fall through */
case PNS_PIPE_DATA:
__skb_pull(skb, 3); /* Pipe data header */
if (!pn_flow_safe(pn->rx_fc)) {
err = sock_queue_rcv_skb(sk, skb);
if (!err)
return NET_RX_SUCCESS;
err = NET_RX_DROP;
break;
}
if (pn->rx_credits == 0) {
atomic_inc(&sk->sk_drops);
err = NET_RX_DROP;
break;
}
pn->rx_credits--;
skb->dev = NULL;
skb_set_owner_r(skb, sk);
skb_queue_tail(&sk->sk_receive_queue, skb);
if (!sock_flag(sk, SOCK_DEAD))
sk->sk_data_ready(sk);
return NET_RX_SUCCESS;
case PNS_PEP_CONNECT_RESP:
if (sk->sk_state != TCP_SYN_SENT)
break;
if (!sock_flag(sk, SOCK_DEAD))
sk->sk_state_change(sk);
if (pep_connresp_rcv(sk, skb)) {
sk->sk_state = TCP_CLOSE_WAIT;
break;
}
if (pn->init_enable == PN_PIPE_DISABLE)
sk->sk_state = TCP_SYN_RECV;
else {
sk->sk_state = TCP_ESTABLISHED;
pipe_start_flow_control(sk);
}
break;
case PNS_PEP_ENABLE_RESP:
if (sk->sk_state != TCP_SYN_SENT)
break;
if (pep_enableresp_rcv(sk, skb)) {
sk->sk_state = TCP_CLOSE_WAIT;
break;
}
sk->sk_state = TCP_ESTABLISHED;
pipe_start_flow_control(sk);
break;
case PNS_PEP_DISCONNECT_RESP:
/* sock should already be dead, nothing to do */
break;
case PNS_PEP_STATUS_IND:
pipe_rcv_status(sk, skb);
break;
}
kfree_skb(skb);
return err;
}
/* Listening sock must be locked */
static struct sock *pep_find_pipe(const struct hlist_head *hlist,
const struct sockaddr_pn *dst,
u8 pipe_handle)
{
struct sock *sknode;
u16 dobj = pn_sockaddr_get_object(dst);
sk_for_each(sknode, hlist) {
struct pep_sock *pnnode = pep_sk(sknode);
/* Ports match, but addresses might not: */
if (pnnode->pn_sk.sobject != dobj)
continue;
if (pnnode->pipe_handle != pipe_handle)
continue;
if (sknode->sk_state == TCP_CLOSE_WAIT)
continue;
sock_hold(sknode);
return sknode;
}
return NULL;
}
/*
* Deliver an skb to a listening sock.
* Socket lock must be held.
* We then queue the skb to the right connected sock (if any).
*/
static int pep_do_rcv(struct sock *sk, struct sk_buff *skb)
{
struct pep_sock *pn = pep_sk(sk);
struct sock *sknode;
struct pnpipehdr *hdr;
struct sockaddr_pn dst;
u8 pipe_handle;
if (!pskb_may_pull(skb, sizeof(*hdr)))
goto drop;
hdr = pnp_hdr(skb);
pipe_handle = hdr->pipe_handle;
if (pipe_handle == PN_PIPE_INVALID_HANDLE)
goto drop;
pn_skb_get_dst_sockaddr(skb, &dst);
/* Look for an existing pipe handle */
sknode = pep_find_pipe(&pn->hlist, &dst, pipe_handle);
if (sknode)
return sk_receive_skb(sknode, skb, 1);
switch (hdr->message_id) {
case PNS_PEP_CONNECT_REQ:
if (sk->sk_state != TCP_LISTEN || sk_acceptq_is_full(sk)) {
pep_reject_conn(sk, skb, PN_PIPE_ERR_PEP_IN_USE,
GFP_ATOMIC);
break;
}
skb_queue_head(&sk->sk_receive_queue, skb);
sk_acceptq_added(sk);
if (!sock_flag(sk, SOCK_DEAD))
sk->sk_data_ready(sk);
return NET_RX_SUCCESS;
case PNS_PEP_DISCONNECT_REQ:
pep_reply(sk, skb, PN_PIPE_NO_ERROR, NULL, 0, GFP_ATOMIC);
break;
case PNS_PEP_CTRL_REQ:
pep_ctrlreq_error(sk, skb, PN_PIPE_INVALID_HANDLE, GFP_ATOMIC);
break;
case PNS_PEP_RESET_REQ:
case PNS_PEP_ENABLE_REQ:
case PNS_PEP_DISABLE_REQ:
/* invalid handle is not even allowed here! */
break;
default:
if ((1 << sk->sk_state)
& ~(TCPF_CLOSE|TCPF_LISTEN|TCPF_CLOSE_WAIT))
/* actively connected socket */
return pipe_handler_do_rcv(sk, skb);
}
drop:
kfree_skb(skb);
return NET_RX_SUCCESS;
}
static int pipe_do_remove(struct sock *sk)
{
struct pep_sock *pn = pep_sk(sk);
struct pnpipehdr *ph;
struct sk_buff *skb;
skb = pep_alloc_skb(sk, NULL, 0, GFP_KERNEL);
if (!skb)
return -ENOMEM;
ph = pnp_hdr(skb);
ph->utid = 0;
ph->message_id = PNS_PIPE_REMOVE_REQ;
ph->pipe_handle = pn->pipe_handle;
ph->data[0] = PAD;
return pn_skb_send(sk, skb, NULL);
}
/* associated socket ceases to exist */
static void pep_sock_close(struct sock *sk, long timeout)
{
struct pep_sock *pn = pep_sk(sk);
int ifindex = 0;
sock_hold(sk); /* keep a reference after sk_common_release() */
sk_common_release(sk);
lock_sock(sk);
if ((1 << sk->sk_state) & (TCPF_SYN_RECV|TCPF_ESTABLISHED)) {
if (sk->sk_backlog_rcv == pipe_do_rcv)
/* Forcefully remove dangling Phonet pipe */
pipe_do_remove(sk);
else
pipe_handler_request(sk, PNS_PEP_DISCONNECT_REQ, PAD,
NULL, 0);
}
sk->sk_state = TCP_CLOSE;
ifindex = pn->ifindex;
pn->ifindex = 0;
release_sock(sk);
if (ifindex)
gprs_detach(sk);
sock_put(sk);
}
static struct sock *pep_sock_accept(struct sock *sk, int flags, int *errp,
bool kern)
{
struct pep_sock *pn = pep_sk(sk), *newpn;
struct sock *newsk = NULL;
struct sk_buff *skb;
struct pnpipehdr *hdr;
struct sockaddr_pn dst, src;
int err;
u16 peer_type;
u8 pipe_handle, enabled, n_sb;
u8 aligned = 0;
skb = skb_recv_datagram(sk, 0, flags & O_NONBLOCK, errp);
if (!skb)
return NULL;
lock_sock(sk);
if (sk->sk_state != TCP_LISTEN) {
err = -EINVAL;
goto drop;
}
sk_acceptq_removed(sk);
err = -EPROTO;
if (!pskb_may_pull(skb, sizeof(*hdr) + 4))
goto drop;
hdr = pnp_hdr(skb);
pipe_handle = hdr->pipe_handle;
switch (hdr->state_after_connect) {
case PN_PIPE_DISABLE:
enabled = 0;
break;
case PN_PIPE_ENABLE:
enabled = 1;
break;
default:
pep_reject_conn(sk, skb, PN_PIPE_ERR_INVALID_PARAM,
GFP_KERNEL);
goto drop;
}
peer_type = hdr->other_pep_type << 8;
/* Parse sub-blocks (options) */
n_sb = hdr->data[4];
while (n_sb > 0) {
u8 type, buf[1], len = sizeof(buf);
const u8 *data = pep_get_sb(skb, &type, &len, buf);
if (data == NULL)
goto drop;
switch (type) {
case PN_PIPE_SB_CONNECT_REQ_PEP_SUB_TYPE:
if (len < 1)
goto drop;
peer_type = (peer_type & 0xff00) | data[0];
break;
case PN_PIPE_SB_ALIGNED_DATA:
aligned = data[0] != 0;
break;
}
n_sb--;
}
/* Check for duplicate pipe handle */
newsk = pep_find_pipe(&pn->hlist, &dst, pipe_handle);
if (unlikely(newsk)) {
__sock_put(newsk);
newsk = NULL;
pep_reject_conn(sk, skb, PN_PIPE_ERR_PEP_IN_USE, GFP_KERNEL);
goto drop;
}
/* Create a new to-be-accepted sock */
newsk = sk_alloc(sock_net(sk), PF_PHONET, GFP_KERNEL, sk->sk_prot,
kern);
if (!newsk) {
pep_reject_conn(sk, skb, PN_PIPE_ERR_OVERLOAD, GFP_KERNEL);
err = -ENOBUFS;
goto drop;
}
sock_init_data(NULL, newsk);
newsk->sk_state = TCP_SYN_RECV;
newsk->sk_backlog_rcv = pipe_do_rcv;
newsk->sk_protocol = sk->sk_protocol;
newsk->sk_destruct = pipe_destruct;
newpn = pep_sk(newsk);
pn_skb_get_dst_sockaddr(skb, &dst);
pn_skb_get_src_sockaddr(skb, &src);
newpn->pn_sk.sobject = pn_sockaddr_get_object(&dst);
newpn->pn_sk.dobject = pn_sockaddr_get_object(&src);
newpn->pn_sk.resource = pn_sockaddr_get_resource(&dst);
sock_hold(sk);
newpn->listener = sk;
skb_queue_head_init(&newpn->ctrlreq_queue);
newpn->pipe_handle = pipe_handle;
atomic_set(&newpn->tx_credits, 0);
newpn->ifindex = 0;
newpn->peer_type = peer_type;
newpn->rx_credits = 0;
newpn->rx_fc = newpn->tx_fc = PN_LEGACY_FLOW_CONTROL;
newpn->init_enable = enabled;
newpn->aligned = aligned;
err = pep_accept_conn(newsk, skb);
if (err) {
sock_put(newsk);
newsk = NULL;
goto drop;
}
sk_add_node(newsk, &pn->hlist);
drop:
release_sock(sk);
kfree_skb(skb);
*errp = err;
return newsk;
}
static int pep_sock_connect(struct sock *sk, struct sockaddr *addr, int len)
{
struct pep_sock *pn = pep_sk(sk);
int err;
u8 data[4] = { 0 /* sub-blocks */, PAD, PAD, PAD };
if (pn->pipe_handle == PN_PIPE_INVALID_HANDLE)
pn->pipe_handle = 1; /* anything but INVALID_HANDLE */
err = pipe_handler_request(sk, PNS_PEP_CONNECT_REQ,
pn->init_enable, data, 4);
if (err) {
pn->pipe_handle = PN_PIPE_INVALID_HANDLE;
return err;
}
sk->sk_state = TCP_SYN_SENT;
return 0;
}
static int pep_sock_enable(struct sock *sk, struct sockaddr *addr, int len)
{
int err;
err = pipe_handler_request(sk, PNS_PEP_ENABLE_REQ, PAD,
NULL, 0);
if (err)
return err;
sk->sk_state = TCP_SYN_SENT;
return 0;
}
static int pep_ioctl(struct sock *sk, int cmd, unsigned long arg)
{
struct pep_sock *pn = pep_sk(sk);
int answ;
int ret = -ENOIOCTLCMD;
switch (cmd) {
case SIOCINQ:
if (sk->sk_state == TCP_LISTEN) {
ret = -EINVAL;
break;
}
lock_sock(sk);
if (sock_flag(sk, SOCK_URGINLINE) &&
!skb_queue_empty(&pn->ctrlreq_queue))
answ = skb_peek(&pn->ctrlreq_queue)->len;
else if (!skb_queue_empty(&sk->sk_receive_queue))
answ = skb_peek(&sk->sk_receive_queue)->len;
else
answ = 0;
release_sock(sk);
ret = put_user(answ, (int __user *)arg);
break;
case SIOCPNENABLEPIPE:
lock_sock(sk);
if (sk->sk_state == TCP_SYN_SENT)
ret = -EBUSY;
else if (sk->sk_state == TCP_ESTABLISHED)
ret = -EISCONN;
else
ret = pep_sock_enable(sk, NULL, 0);
release_sock(sk);
break;
}
return ret;
}
static int pep_init(struct sock *sk)
{
struct pep_sock *pn = pep_sk(sk);
sk->sk_destruct = pipe_destruct;
INIT_HLIST_HEAD(&pn->hlist);
pn->listener = NULL;
skb_queue_head_init(&pn->ctrlreq_queue);
atomic_set(&pn->tx_credits, 0);
pn->ifindex = 0;
pn->peer_type = 0;
pn->pipe_handle = PN_PIPE_INVALID_HANDLE;
pn->rx_credits = 0;
pn->rx_fc = pn->tx_fc = PN_LEGACY_FLOW_CONTROL;
pn->init_enable = 1;
pn->aligned = 0;
return 0;
}
static int pep_setsockopt(struct sock *sk, int level, int optname,
char __user *optval, unsigned int optlen)
{
struct pep_sock *pn = pep_sk(sk);
int val = 0, err = 0;
if (level != SOL_PNPIPE)
return -ENOPROTOOPT;
if (optlen >= sizeof(int)) {
if (get_user(val, (int __user *) optval))
return -EFAULT;
}
lock_sock(sk);
switch (optname) {
case PNPIPE_ENCAP:
if (val && val != PNPIPE_ENCAP_IP) {
err = -EINVAL;
break;
}
if (!pn->ifindex == !val)
break; /* Nothing to do! */
if (!capable(CAP_NET_ADMIN)) {
err = -EPERM;
break;
}
if (val) {
release_sock(sk);
err = gprs_attach(sk);
if (err > 0) {
pn->ifindex = err;
err = 0;
}
} else {
pn->ifindex = 0;
release_sock(sk);
gprs_detach(sk);
err = 0;
}
goto out_norel;
case PNPIPE_HANDLE:
if ((sk->sk_state == TCP_CLOSE) &&
(val >= 0) && (val < PN_PIPE_INVALID_HANDLE))
pn->pipe_handle = val;
else
err = -EINVAL;
break;
case PNPIPE_INITSTATE:
pn->init_enable = !!val;
break;
default:
err = -ENOPROTOOPT;
}
release_sock(sk);
out_norel:
return err;
}
static int pep_getsockopt(struct sock *sk, int level, int optname,
char __user *optval, int __user *optlen)
{
struct pep_sock *pn = pep_sk(sk);
int len, val;
if (level != SOL_PNPIPE)
return -ENOPROTOOPT;
if (get_user(len, optlen))
return -EFAULT;
switch (optname) {
case PNPIPE_ENCAP:
val = pn->ifindex ? PNPIPE_ENCAP_IP : PNPIPE_ENCAP_NONE;
break;
case PNPIPE_IFINDEX:
val = pn->ifindex;
break;
case PNPIPE_HANDLE:
val = pn->pipe_handle;
if (val == PN_PIPE_INVALID_HANDLE)
return -EINVAL;
break;
case PNPIPE_INITSTATE:
val = pn->init_enable;
break;
default:
return -ENOPROTOOPT;
}
len = min_t(unsigned int, sizeof(int), len);
if (put_user(len, optlen))
return -EFAULT;
if (put_user(val, (int __user *) optval))
return -EFAULT;
return 0;
}
static int pipe_skb_send(struct sock *sk, struct sk_buff *skb)
{
struct pep_sock *pn = pep_sk(sk);
struct pnpipehdr *ph;
int err;
if (pn_flow_safe(pn->tx_fc) &&
!atomic_add_unless(&pn->tx_credits, -1, 0)) {
kfree_skb(skb);
return -ENOBUFS;
}
skb_push(skb, 3 + pn->aligned);
skb_reset_transport_header(skb);
ph = pnp_hdr(skb);
ph->utid = 0;
if (pn->aligned) {
ph->message_id = PNS_PIPE_ALIGNED_DATA;
ph->data[0] = 0; /* padding */
} else
ph->message_id = PNS_PIPE_DATA;
ph->pipe_handle = pn->pipe_handle;
err = pn_skb_send(sk, skb, NULL);
if (err && pn_flow_safe(pn->tx_fc))
atomic_inc(&pn->tx_credits);
return err;
}
static int pep_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
{
struct pep_sock *pn = pep_sk(sk);
struct sk_buff *skb;
long timeo;
int flags = msg->msg_flags;
int err, done;
if (len > USHRT_MAX)
return -EMSGSIZE;
if ((msg->msg_flags & ~(MSG_DONTWAIT|MSG_EOR|MSG_NOSIGNAL|
MSG_CMSG_COMPAT)) ||
!(msg->msg_flags & MSG_EOR))
return -EOPNOTSUPP;
skb = sock_alloc_send_skb(sk, MAX_PNPIPE_HEADER + len,
flags & MSG_DONTWAIT, &err);
if (!skb)
return err;
skb_reserve(skb, MAX_PHONET_HEADER + 3 + pn->aligned);
err = memcpy_from_msg(skb_put(skb, len), msg, len);
if (err < 0)
goto outfree;
lock_sock(sk);
timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
if ((1 << sk->sk_state) & (TCPF_LISTEN|TCPF_CLOSE)) {
err = -ENOTCONN;
goto out;
}
if (sk->sk_state != TCP_ESTABLISHED) {
/* Wait until the pipe gets to enabled state */
disabled:
err = sk_stream_wait_connect(sk, &timeo);
if (err)
goto out;
if (sk->sk_state == TCP_CLOSE_WAIT) {
err = -ECONNRESET;
goto out;
}
}
BUG_ON(sk->sk_state != TCP_ESTABLISHED);
/* Wait until flow control allows TX */
done = atomic_read(&pn->tx_credits);
while (!done) {
DEFINE_WAIT_FUNC(wait, woken_wake_function);
if (!timeo) {
err = -EAGAIN;
goto out;
}
if (signal_pending(current)) {
err = sock_intr_errno(timeo);
goto out;
}
add_wait_queue(sk_sleep(sk), &wait);
done = sk_wait_event(sk, &timeo, atomic_read(&pn->tx_credits), &wait);
remove_wait_queue(sk_sleep(sk), &wait);
if (sk->sk_state != TCP_ESTABLISHED)
goto disabled;
}
err = pipe_skb_send(sk, skb);
if (err >= 0)
err = len; /* success! */
skb = NULL;
out:
release_sock(sk);
outfree:
kfree_skb(skb);
return err;
}
int pep_writeable(struct sock *sk)
{
struct pep_sock *pn = pep_sk(sk);
return atomic_read(&pn->tx_credits);
}
int pep_write(struct sock *sk, struct sk_buff *skb)
{
struct sk_buff *rskb, *fs;
int flen = 0;
if (pep_sk(sk)->aligned)
return pipe_skb_send(sk, skb);
rskb = alloc_skb(MAX_PNPIPE_HEADER, GFP_ATOMIC);
if (!rskb) {
kfree_skb(skb);
return -ENOMEM;
}
skb_shinfo(rskb)->frag_list = skb;
rskb->len += skb->len;
rskb->data_len += rskb->len;
rskb->truesize += rskb->len;
/* Avoid nested fragments */
skb_walk_frags(skb, fs)
flen += fs->len;
skb->next = skb_shinfo(skb)->frag_list;
skb_frag_list_init(skb);
skb->len -= flen;
skb->data_len -= flen;
skb->truesize -= flen;
skb_reserve(rskb, MAX_PHONET_HEADER + 3);
return pipe_skb_send(sk, rskb);
}
struct sk_buff *pep_read(struct sock *sk)
{
struct sk_buff *skb = skb_dequeue(&sk->sk_receive_queue);
if (sk->sk_state == TCP_ESTABLISHED)
pipe_grant_credits(sk, GFP_ATOMIC);
return skb;
}
static int pep_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
int noblock, int flags, int *addr_len)
{
struct sk_buff *skb;
int err;
if (flags & ~(MSG_OOB|MSG_PEEK|MSG_TRUNC|MSG_DONTWAIT|MSG_WAITALL|
MSG_NOSIGNAL|MSG_CMSG_COMPAT))
return -EOPNOTSUPP;
if (unlikely(1 << sk->sk_state & (TCPF_LISTEN | TCPF_CLOSE)))
return -ENOTCONN;
if ((flags & MSG_OOB) || sock_flag(sk, SOCK_URGINLINE)) {
/* Dequeue and acknowledge control request */
struct pep_sock *pn = pep_sk(sk);
if (flags & MSG_PEEK)
return -EOPNOTSUPP;
skb = skb_dequeue(&pn->ctrlreq_queue);
if (skb) {
pep_ctrlreq_error(sk, skb, PN_PIPE_NO_ERROR,
GFP_KERNEL);
msg->msg_flags |= MSG_OOB;
goto copy;
}
if (flags & MSG_OOB)
return -EINVAL;
}
skb = skb_recv_datagram(sk, flags, noblock, &err);
lock_sock(sk);
if (skb == NULL) {
if (err == -ENOTCONN && sk->sk_state == TCP_CLOSE_WAIT)
err = -ECONNRESET;
release_sock(sk);
return err;
}
if (sk->sk_state == TCP_ESTABLISHED)
pipe_grant_credits(sk, GFP_KERNEL);
release_sock(sk);
copy:
msg->msg_flags |= MSG_EOR;
if (skb->len > len)
msg->msg_flags |= MSG_TRUNC;
else
len = skb->len;
err = skb_copy_datagram_msg(skb, 0, msg, len);
if (!err)
err = (flags & MSG_TRUNC) ? skb->len : len;
skb_free_datagram(sk, skb);
return err;
}
static void pep_sock_unhash(struct sock *sk)
{
struct pep_sock *pn = pep_sk(sk);
struct sock *skparent = NULL;
lock_sock(sk);
if (pn->listener != NULL) {
skparent = pn->listener;
pn->listener = NULL;
release_sock(sk);
pn = pep_sk(skparent);
lock_sock(skparent);
sk_del_node_init(sk);
sk = skparent;
}
/* Unhash a listening sock only when it is closed
* and all of its active connected pipes are closed. */
if (hlist_empty(&pn->hlist))
pn_sock_unhash(&pn->pn_sk.sk);
release_sock(sk);
if (skparent)
sock_put(skparent);
}
static struct proto pep_proto = {
.close = pep_sock_close,
.accept = pep_sock_accept,
.connect = pep_sock_connect,
.ioctl = pep_ioctl,
.init = pep_init,
.setsockopt = pep_setsockopt,
.getsockopt = pep_getsockopt,
.sendmsg = pep_sendmsg,
.recvmsg = pep_recvmsg,
.backlog_rcv = pep_do_rcv,
.hash = pn_sock_hash,
.unhash = pep_sock_unhash,
.get_port = pn_sock_get_port,
.obj_size = sizeof(struct pep_sock),
.owner = THIS_MODULE,
.name = "PNPIPE",
};
static struct phonet_protocol pep_pn_proto = {
.ops = &phonet_stream_ops,
.prot = &pep_proto,
.sock_type = SOCK_SEQPACKET,
};
static int __init pep_register(void)
{
return phonet_proto_register(PN_PROTO_PIPE, &pep_pn_proto);
}
static void __exit pep_unregister(void)
{
phonet_proto_unregister(PN_PROTO_PIPE, &pep_pn_proto);
}
module_init(pep_register);
module_exit(pep_unregister);
MODULE_AUTHOR("Remi Denis-Courmont, Nokia");
MODULE_DESCRIPTION("Phonet pipe protocol");
MODULE_LICENSE("GPL");
MODULE_ALIAS_NET_PF_PROTO(PF_PHONET, PN_PROTO_PIPE);
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