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linux/net/llc/af_llc.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

1256 lines
31 KiB
C
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/*
* af_llc.c - LLC User Interface SAPs
* Description:
* Functions in this module are implementation of socket based llc
* communications for the Linux operating system. Support of llc class
* one and class two is provided via SOCK_DGRAM and SOCK_STREAM
* respectively.
*
* An llc2 connection is (mac + sap), only one llc2 sap connection
* is allowed per mac. Though one sap may have multiple mac + sap
* connections.
*
* Copyright (c) 2001 by Jay Schulist <jschlst@samba.org>
* 2002-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
*
* This program can be redistributed or modified under the terms of the
* GNU General Public License as published by the Free Software Foundation.
* This program is distributed without any warranty or implied warranty
* of merchantability or fitness for a particular purpose.
*
* See the GNU General Public License for more details.
*/
#include <linux/compiler.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/rtnetlink.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/sched/signal.h>
#include <net/llc.h>
#include <net/llc_sap.h>
#include <net/llc_pdu.h>
#include <net/llc_conn.h>
#include <net/tcp_states.h>
/* remember: uninitialized global data is zeroed because its in .bss */
static u16 llc_ui_sap_last_autoport = LLC_SAP_DYN_START;
static u16 llc_ui_sap_link_no_max[256];
static struct sockaddr_llc llc_ui_addrnull;
static const struct proto_ops llc_ui_ops;
static bool llc_ui_wait_for_conn(struct sock *sk, long timeout);
static int llc_ui_wait_for_disc(struct sock *sk, long timeout);
static int llc_ui_wait_for_busy_core(struct sock *sk, long timeout);
#if 0
#define dprintk(args...) printk(KERN_DEBUG args)
#else
#define dprintk(args...)
#endif
/* Maybe we'll add some more in the future. */
#define LLC_CMSG_PKTINFO 1
/**
* llc_ui_next_link_no - return the next unused link number for a sap
* @sap: Address of sap to get link number from.
*
* Return the next unused link number for a given sap.
*/
static inline u16 llc_ui_next_link_no(int sap)
{
return llc_ui_sap_link_no_max[sap]++;
}
/**
* llc_proto_type - return eth protocol for ARP header type
* @arphrd: ARP header type.
*
* Given an ARP header type return the corresponding ethernet protocol.
*/
static inline __be16 llc_proto_type(u16 arphrd)
{
return htons(ETH_P_802_2);
}
/**
* llc_ui_addr_null - determines if a address structure is null
* @addr: Address to test if null.
*/
static inline u8 llc_ui_addr_null(struct sockaddr_llc *addr)
{
return !memcmp(addr, &llc_ui_addrnull, sizeof(*addr));
}
/**
* llc_ui_header_len - return length of llc header based on operation
* @sk: Socket which contains a valid llc socket type.
* @addr: Complete sockaddr_llc structure received from the user.
*
* Provide the length of the llc header depending on what kind of
* operation the user would like to perform and the type of socket.
* Returns the correct llc header length.
*/
static inline u8 llc_ui_header_len(struct sock *sk, struct sockaddr_llc *addr)
{
u8 rc = LLC_PDU_LEN_U;
if (addr->sllc_test || addr->sllc_xid)
rc = LLC_PDU_LEN_U;
else if (sk->sk_type == SOCK_STREAM)
rc = LLC_PDU_LEN_I;
return rc;
}
/**
* llc_ui_send_data - send data via reliable llc2 connection
* @sk: Connection the socket is using.
* @skb: Data the user wishes to send.
* @noblock: can we block waiting for data?
*
* Send data via reliable llc2 connection.
* Returns 0 upon success, non-zero if action did not succeed.
*/
static int llc_ui_send_data(struct sock* sk, struct sk_buff *skb, int noblock)
{
struct llc_sock* llc = llc_sk(sk);
int rc = 0;
if (unlikely(llc_data_accept_state(llc->state) ||
llc->remote_busy_flag ||
llc->p_flag)) {
long timeout = sock_sndtimeo(sk, noblock);
rc = llc_ui_wait_for_busy_core(sk, timeout);
}
if (unlikely(!rc))
rc = llc_build_and_send_pkt(sk, skb);
return rc;
}
static void llc_ui_sk_init(struct socket *sock, struct sock *sk)
{
sock_graft(sk, sock);
sk->sk_type = sock->type;
sock->ops = &llc_ui_ops;
}
static struct proto llc_proto = {
.name = "LLC",
.owner = THIS_MODULE,
.obj_size = sizeof(struct llc_sock),
.slab_flags = SLAB_DESTROY_BY_RCU,
};
/**
* llc_ui_create - alloc and init a new llc_ui socket
* @net: network namespace (must be default network)
* @sock: Socket to initialize and attach allocated sk to.
* @protocol: Unused.
* @kern: on behalf of kernel or userspace
*
* Allocate and initialize a new llc_ui socket, validate the user wants a
* socket type we have available.
* Returns 0 upon success, negative upon failure.
*/
static int llc_ui_create(struct net *net, struct socket *sock, int protocol,
int kern)
{
struct sock *sk;
int rc = -ESOCKTNOSUPPORT;
if (!ns_capable(net->user_ns, CAP_NET_RAW))
return -EPERM;
if (!net_eq(net, &init_net))
return -EAFNOSUPPORT;
if (likely(sock->type == SOCK_DGRAM || sock->type == SOCK_STREAM)) {
rc = -ENOMEM;
sk = llc_sk_alloc(net, PF_LLC, GFP_KERNEL, &llc_proto, kern);
if (sk) {
rc = 0;
llc_ui_sk_init(sock, sk);
}
}
return rc;
}
/**
* llc_ui_release - shutdown socket
* @sock: Socket to release.
*
* Shutdown and deallocate an existing socket.
*/
static int llc_ui_release(struct socket *sock)
{
struct sock *sk = sock->sk;
struct llc_sock *llc;
if (unlikely(sk == NULL))
goto out;
sock_hold(sk);
lock_sock(sk);
llc = llc_sk(sk);
dprintk("%s: closing local(%02X) remote(%02X)\n", __func__,
llc->laddr.lsap, llc->daddr.lsap);
if (!llc_send_disc(sk))
llc_ui_wait_for_disc(sk, sk->sk_rcvtimeo);
if (!sock_flag(sk, SOCK_ZAPPED))
llc_sap_remove_socket(llc->sap, sk);
release_sock(sk);
if (llc->dev)
dev_put(llc->dev);
sock_put(sk);
llc_sk_free(sk);
out:
return 0;
}
/**
* llc_ui_autoport - provide dynamically allocate SAP number
*
* Provide the caller with a dynamically allocated SAP number according
* to the rules that are set in this function. Returns: 0, upon failure,
* SAP number otherwise.
*/
static int llc_ui_autoport(void)
{
struct llc_sap *sap;
int i, tries = 0;
while (tries < LLC_SAP_DYN_TRIES) {
for (i = llc_ui_sap_last_autoport;
i < LLC_SAP_DYN_STOP; i += 2) {
sap = llc_sap_find(i);
if (!sap) {
llc_ui_sap_last_autoport = i + 2;
goto out;
}
llc_sap_put(sap);
}
llc_ui_sap_last_autoport = LLC_SAP_DYN_START;
tries++;
}
i = 0;
out:
return i;
}
/**
* llc_ui_autobind - automatically bind a socket to a sap
* @sock: socket to bind
* @addr: address to connect to
*
* Used by llc_ui_connect and llc_ui_sendmsg when the user hasn't
* specifically used llc_ui_bind to bind to an specific address/sap
*
* Returns: 0 upon success, negative otherwise.
*/
static int llc_ui_autobind(struct socket *sock, struct sockaddr_llc *addr)
{
struct sock *sk = sock->sk;
struct llc_sock *llc = llc_sk(sk);
struct llc_sap *sap;
int rc = -EINVAL;
if (!sock_flag(sk, SOCK_ZAPPED))
goto out;
rc = -ENODEV;
if (sk->sk_bound_dev_if) {
llc->dev = dev_get_by_index(&init_net, sk->sk_bound_dev_if);
if (llc->dev && addr->sllc_arphrd != llc->dev->type) {
dev_put(llc->dev);
llc->dev = NULL;
}
} else
llc->dev = dev_getfirstbyhwtype(&init_net, addr->sllc_arphrd);
if (!llc->dev)
goto out;
rc = -EUSERS;
llc->laddr.lsap = llc_ui_autoport();
if (!llc->laddr.lsap)
goto out;
rc = -EBUSY; /* some other network layer is using the sap */
sap = llc_sap_open(llc->laddr.lsap, NULL);
if (!sap)
goto out;
memcpy(llc->laddr.mac, llc->dev->dev_addr, IFHWADDRLEN);
memcpy(&llc->addr, addr, sizeof(llc->addr));
/* assign new connection to its SAP */
llc_sap_add_socket(sap, sk);
sock_reset_flag(sk, SOCK_ZAPPED);
rc = 0;
out:
return rc;
}
/**
* llc_ui_bind - bind a socket to a specific address.
* @sock: Socket to bind an address to.
* @uaddr: Address the user wants the socket bound to.
* @addrlen: Length of the uaddr structure.
*
* Bind a socket to a specific address. For llc a user is able to bind to
* a specific sap only or mac + sap.
* If the user desires to bind to a specific mac + sap, it is possible to
* have multiple sap connections via multiple macs.
* Bind and autobind for that matter must enforce the correct sap usage
* otherwise all hell will break loose.
* Returns: 0 upon success, negative otherwise.
*/
static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen)
{
struct sockaddr_llc *addr = (struct sockaddr_llc *)uaddr;
struct sock *sk = sock->sk;
struct llc_sock *llc = llc_sk(sk);
struct llc_sap *sap;
int rc = -EINVAL;
dprintk("%s: binding %02X\n", __func__, addr->sllc_sap);
if (unlikely(!sock_flag(sk, SOCK_ZAPPED) || addrlen != sizeof(*addr)))
goto out;
rc = -EAFNOSUPPORT;
if (unlikely(addr->sllc_family != AF_LLC))
goto out;
rc = -ENODEV;
rcu_read_lock();
if (sk->sk_bound_dev_if) {
llc->dev = dev_get_by_index_rcu(&init_net, sk->sk_bound_dev_if);
if (llc->dev) {
if (!addr->sllc_arphrd)
addr->sllc_arphrd = llc->dev->type;
if (is_zero_ether_addr(addr->sllc_mac))
memcpy(addr->sllc_mac, llc->dev->dev_addr,
IFHWADDRLEN);
if (addr->sllc_arphrd != llc->dev->type ||
!ether_addr_equal(addr->sllc_mac,
llc->dev->dev_addr)) {
rc = -EINVAL;
llc->dev = NULL;
}
}
} else
llc->dev = dev_getbyhwaddr_rcu(&init_net, addr->sllc_arphrd,
addr->sllc_mac);
if (llc->dev)
dev_hold(llc->dev);
rcu_read_unlock();
if (!llc->dev)
goto out;
if (!addr->sllc_sap) {
rc = -EUSERS;
addr->sllc_sap = llc_ui_autoport();
if (!addr->sllc_sap)
goto out;
}
sap = llc_sap_find(addr->sllc_sap);
if (!sap) {
sap = llc_sap_open(addr->sllc_sap, NULL);
rc = -EBUSY; /* some other network layer is using the sap */
if (!sap)
goto out;
} else {
struct llc_addr laddr, daddr;
struct sock *ask;
memset(&laddr, 0, sizeof(laddr));
memset(&daddr, 0, sizeof(daddr));
/*
* FIXME: check if the address is multicast,
* only SOCK_DGRAM can do this.
*/
memcpy(laddr.mac, addr->sllc_mac, IFHWADDRLEN);
laddr.lsap = addr->sllc_sap;
rc = -EADDRINUSE; /* mac + sap clash. */
ask = llc_lookup_established(sap, &daddr, &laddr);
if (ask) {
sock_put(ask);
goto out_put;
}
}
llc->laddr.lsap = addr->sllc_sap;
memcpy(llc->laddr.mac, addr->sllc_mac, IFHWADDRLEN);
memcpy(&llc->addr, addr, sizeof(llc->addr));
/* assign new connection to its SAP */
llc_sap_add_socket(sap, sk);
sock_reset_flag(sk, SOCK_ZAPPED);
rc = 0;
out_put:
llc_sap_put(sap);
out:
return rc;
}
/**
* llc_ui_shutdown - shutdown a connect llc2 socket.
* @sock: Socket to shutdown.
* @how: What part of the socket to shutdown.
*
* Shutdown a connected llc2 socket. Currently this function only supports
* shutting down both sends and receives (2), we could probably make this
* function such that a user can shutdown only half the connection but not
* right now.
* Returns: 0 upon success, negative otherwise.
*/
static int llc_ui_shutdown(struct socket *sock, int how)
{
struct sock *sk = sock->sk;
int rc = -ENOTCONN;
lock_sock(sk);
if (unlikely(sk->sk_state != TCP_ESTABLISHED))
goto out;
rc = -EINVAL;
if (how != 2)
goto out;
rc = llc_send_disc(sk);
if (!rc)
rc = llc_ui_wait_for_disc(sk, sk->sk_rcvtimeo);
/* Wake up anyone sleeping in poll */
sk->sk_state_change(sk);
out:
release_sock(sk);
return rc;
}
/**
* llc_ui_connect - Connect to a remote llc2 mac + sap.
* @sock: Socket which will be connected to the remote destination.
* @uaddr: Remote and possibly the local address of the new connection.
* @addrlen: Size of uaddr structure.
* @flags: Operational flags specified by the user.
*
* Connect to a remote llc2 mac + sap. The caller must specify the
* destination mac and address to connect to. If the user hasn't previously
* called bind(2) with a smac the address of the first interface of the
* specified arp type will be used.
* This function will autobind if user did not previously call bind.
* Returns: 0 upon success, negative otherwise.
*/
static int llc_ui_connect(struct socket *sock, struct sockaddr *uaddr,
int addrlen, int flags)
{
struct sock *sk = sock->sk;
struct llc_sock *llc = llc_sk(sk);
struct sockaddr_llc *addr = (struct sockaddr_llc *)uaddr;
int rc = -EINVAL;
lock_sock(sk);
if (unlikely(addrlen != sizeof(*addr)))
goto out;
rc = -EAFNOSUPPORT;
if (unlikely(addr->sllc_family != AF_LLC))
goto out;
if (unlikely(sk->sk_type != SOCK_STREAM))
goto out;
rc = -EALREADY;
if (unlikely(sock->state == SS_CONNECTING))
goto out;
/* bind connection to sap if user hasn't done it. */
if (sock_flag(sk, SOCK_ZAPPED)) {
/* bind to sap with null dev, exclusive */
rc = llc_ui_autobind(sock, addr);
if (rc)
goto out;
}
llc->daddr.lsap = addr->sllc_sap;
memcpy(llc->daddr.mac, addr->sllc_mac, IFHWADDRLEN);
sock->state = SS_CONNECTING;
sk->sk_state = TCP_SYN_SENT;
llc->link = llc_ui_next_link_no(llc->sap->laddr.lsap);
rc = llc_establish_connection(sk, llc->dev->dev_addr,
addr->sllc_mac, addr->sllc_sap);
if (rc) {
dprintk("%s: llc_ui_send_conn failed :-(\n", __func__);
sock->state = SS_UNCONNECTED;
sk->sk_state = TCP_CLOSE;
goto out;
}
if (sk->sk_state == TCP_SYN_SENT) {
const long timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
if (!timeo || !llc_ui_wait_for_conn(sk, timeo))
goto out;
rc = sock_intr_errno(timeo);
if (signal_pending(current))
goto out;
}
if (sk->sk_state == TCP_CLOSE)
goto sock_error;
sock->state = SS_CONNECTED;
rc = 0;
out:
release_sock(sk);
return rc;
sock_error:
rc = sock_error(sk) ? : -ECONNABORTED;
sock->state = SS_UNCONNECTED;
goto out;
}
/**
* llc_ui_listen - allow a normal socket to accept incoming connections
* @sock: Socket to allow incoming connections on.
* @backlog: Number of connections to queue.
*
* Allow a normal socket to accept incoming connections.
* Returns 0 upon success, negative otherwise.
*/
static int llc_ui_listen(struct socket *sock, int backlog)
{
struct sock *sk = sock->sk;
int rc = -EINVAL;
lock_sock(sk);
if (unlikely(sock->state != SS_UNCONNECTED))
goto out;
rc = -EOPNOTSUPP;
if (unlikely(sk->sk_type != SOCK_STREAM))
goto out;
rc = -EAGAIN;
if (sock_flag(sk, SOCK_ZAPPED))
goto out;
rc = 0;
if (!(unsigned int)backlog) /* BSDism */
backlog = 1;
sk->sk_max_ack_backlog = backlog;
if (sk->sk_state != TCP_LISTEN) {
sk->sk_ack_backlog = 0;
sk->sk_state = TCP_LISTEN;
}
sk->sk_socket->flags |= __SO_ACCEPTCON;
out:
release_sock(sk);
return rc;
}
static int llc_ui_wait_for_disc(struct sock *sk, long timeout)
{
DEFINE_WAIT_FUNC(wait, woken_wake_function);
int rc = 0;
add_wait_queue(sk_sleep(sk), &wait);
while (1) {
if (sk_wait_event(sk, &timeout, sk->sk_state == TCP_CLOSE, &wait))
break;
rc = -ERESTARTSYS;
if (signal_pending(current))
break;
rc = -EAGAIN;
if (!timeout)
break;
rc = 0;
}
remove_wait_queue(sk_sleep(sk), &wait);
return rc;
}
static bool llc_ui_wait_for_conn(struct sock *sk, long timeout)
{
DEFINE_WAIT_FUNC(wait, woken_wake_function);
add_wait_queue(sk_sleep(sk), &wait);
while (1) {
if (sk_wait_event(sk, &timeout, sk->sk_state != TCP_SYN_SENT, &wait))
break;
if (signal_pending(current) || !timeout)
break;
}
remove_wait_queue(sk_sleep(sk), &wait);
return timeout;
}
static int llc_ui_wait_for_busy_core(struct sock *sk, long timeout)
{
DEFINE_WAIT_FUNC(wait, woken_wake_function);
struct llc_sock *llc = llc_sk(sk);
int rc;
add_wait_queue(sk_sleep(sk), &wait);
while (1) {
rc = 0;
if (sk_wait_event(sk, &timeout,
(sk->sk_shutdown & RCV_SHUTDOWN) ||
(!llc_data_accept_state(llc->state) &&
!llc->remote_busy_flag &&
!llc->p_flag), &wait))
break;
rc = -ERESTARTSYS;
if (signal_pending(current))
break;
rc = -EAGAIN;
if (!timeout)
break;
}
remove_wait_queue(sk_sleep(sk), &wait);
return rc;
}
static int llc_wait_data(struct sock *sk, long timeo)
{
int rc;
while (1) {
/*
* POSIX 1003.1g mandates this order.
*/
rc = sock_error(sk);
if (rc)
break;
rc = 0;
if (sk->sk_shutdown & RCV_SHUTDOWN)
break;
rc = -EAGAIN;
if (!timeo)
break;
rc = sock_intr_errno(timeo);
if (signal_pending(current))
break;
rc = 0;
if (sk_wait_data(sk, &timeo, NULL))
break;
}
return rc;
}
static void llc_cmsg_rcv(struct msghdr *msg, struct sk_buff *skb)
{
struct llc_sock *llc = llc_sk(skb->sk);
if (llc->cmsg_flags & LLC_CMSG_PKTINFO) {
struct llc_pktinfo info;
memset(&info, 0, sizeof(info));
info.lpi_ifindex = llc_sk(skb->sk)->dev->ifindex;
llc_pdu_decode_dsap(skb, &info.lpi_sap);
llc_pdu_decode_da(skb, info.lpi_mac);
put_cmsg(msg, SOL_LLC, LLC_OPT_PKTINFO, sizeof(info), &info);
}
}
/**
* llc_ui_accept - accept a new incoming connection.
* @sock: Socket which connections arrive on.
* @newsock: Socket to move incoming connection to.
* @flags: User specified operational flags.
* @kern: If the socket is kernel internal
*
* Accept a new incoming connection.
* Returns 0 upon success, negative otherwise.
*/
static int llc_ui_accept(struct socket *sock, struct socket *newsock, int flags,
bool kern)
{
struct sock *sk = sock->sk, *newsk;
struct llc_sock *llc, *newllc;
struct sk_buff *skb;
int rc = -EOPNOTSUPP;
dprintk("%s: accepting on %02X\n", __func__,
llc_sk(sk)->laddr.lsap);
lock_sock(sk);
if (unlikely(sk->sk_type != SOCK_STREAM))
goto out;
rc = -EINVAL;
if (unlikely(sock->state != SS_UNCONNECTED ||
sk->sk_state != TCP_LISTEN))
goto out;
/* wait for a connection to arrive. */
if (skb_queue_empty(&sk->sk_receive_queue)) {
rc = llc_wait_data(sk, sk->sk_rcvtimeo);
if (rc)
goto out;
}
dprintk("%s: got a new connection on %02X\n", __func__,
llc_sk(sk)->laddr.lsap);
skb = skb_dequeue(&sk->sk_receive_queue);
rc = -EINVAL;
if (!skb->sk)
goto frees;
rc = 0;
newsk = skb->sk;
/* attach connection to a new socket. */
llc_ui_sk_init(newsock, newsk);
sock_reset_flag(newsk, SOCK_ZAPPED);
newsk->sk_state = TCP_ESTABLISHED;
newsock->state = SS_CONNECTED;
llc = llc_sk(sk);
newllc = llc_sk(newsk);
memcpy(&newllc->addr, &llc->addr, sizeof(newllc->addr));
newllc->link = llc_ui_next_link_no(newllc->laddr.lsap);
/* put original socket back into a clean listen state. */
sk->sk_state = TCP_LISTEN;
sk->sk_ack_backlog--;
dprintk("%s: ok success on %02X, client on %02X\n", __func__,
llc_sk(sk)->addr.sllc_sap, newllc->daddr.lsap);
frees:
kfree_skb(skb);
out:
release_sock(sk);
return rc;
}
/**
* llc_ui_recvmsg - copy received data to the socket user.
* @sock: Socket to copy data from.
* @msg: Various user space related information.
* @len: Size of user buffer.
* @flags: User specified flags.
*
* Copy received data to the socket user.
* Returns non-negative upon success, negative otherwise.
*/
static int llc_ui_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
int flags)
{
DECLARE_SOCKADDR(struct sockaddr_llc *, uaddr, msg->msg_name);
const int nonblock = flags & MSG_DONTWAIT;
struct sk_buff *skb = NULL;
struct sock *sk = sock->sk;
struct llc_sock *llc = llc_sk(sk);
unsigned long cpu_flags;
size_t copied = 0;
u32 peek_seq = 0;
u32 *seq, skb_len;
unsigned long used;
int target; /* Read at least this many bytes */
long timeo;
lock_sock(sk);
copied = -ENOTCONN;
if (unlikely(sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_LISTEN))
goto out;
timeo = sock_rcvtimeo(sk, nonblock);
seq = &llc->copied_seq;
if (flags & MSG_PEEK) {
peek_seq = llc->copied_seq;
seq = &peek_seq;
}
target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
copied = 0;
do {
u32 offset;
/*
* We need to check signals first, to get correct SIGURG
* handling. FIXME: Need to check this doesn't impact 1003.1g
* and move it down to the bottom of the loop
*/
if (signal_pending(current)) {
if (copied)
break;
copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
break;
}
/* Next get a buffer. */
skb = skb_peek(&sk->sk_receive_queue);
if (skb) {
offset = *seq;
goto found_ok_skb;
}
/* Well, if we have backlog, try to process it now yet. */
if (copied >= target && !sk->sk_backlog.tail)
break;
if (copied) {
if (sk->sk_err ||
sk->sk_state == TCP_CLOSE ||
(sk->sk_shutdown & RCV_SHUTDOWN) ||
!timeo ||
(flags & MSG_PEEK))
break;
} else {
if (sock_flag(sk, SOCK_DONE))
break;
if (sk->sk_err) {
copied = sock_error(sk);
break;
}
if (sk->sk_shutdown & RCV_SHUTDOWN)
break;
if (sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_CLOSE) {
if (!sock_flag(sk, SOCK_DONE)) {
/*
* This occurs when user tries to read
* from never connected socket.
*/
copied = -ENOTCONN;
break;
}
break;
}
if (!timeo) {
copied = -EAGAIN;
break;
}
}
if (copied >= target) { /* Do not sleep, just process backlog. */
release_sock(sk);
lock_sock(sk);
} else
sk_wait_data(sk, &timeo, NULL);
if ((flags & MSG_PEEK) && peek_seq != llc->copied_seq) {
net_dbg_ratelimited("LLC(%s:%d): Application bug, race in MSG_PEEK\n",
current->comm,
task_pid_nr(current));
peek_seq = llc->copied_seq;
}
continue;
found_ok_skb:
skb_len = skb->len;
/* Ok so how much can we use? */
used = skb->len - offset;
if (len < used)
used = len;
if (!(flags & MSG_TRUNC)) {
int rc = skb_copy_datagram_msg(skb, offset, msg, used);
if (rc) {
/* Exception. Bailout! */
if (!copied)
copied = -EFAULT;
break;
}
}
*seq += used;
copied += used;
len -= used;
/* For non stream protcols we get one packet per recvmsg call */
if (sk->sk_type != SOCK_STREAM)
goto copy_uaddr;
if (!(flags & MSG_PEEK)) {
spin_lock_irqsave(&sk->sk_receive_queue.lock, cpu_flags);
sk_eat_skb(sk, skb);
spin_unlock_irqrestore(&sk->sk_receive_queue.lock, cpu_flags);
*seq = 0;
}
/* Partial read */
if (used + offset < skb_len)
continue;
} while (len > 0);
out:
release_sock(sk);
return copied;
copy_uaddr:
if (uaddr != NULL && skb != NULL) {
memcpy(uaddr, llc_ui_skb_cb(skb), sizeof(*uaddr));
msg->msg_namelen = sizeof(*uaddr);
}
if (llc_sk(sk)->cmsg_flags)
llc_cmsg_rcv(msg, skb);
if (!(flags & MSG_PEEK)) {
spin_lock_irqsave(&sk->sk_receive_queue.lock, cpu_flags);
sk_eat_skb(sk, skb);
spin_unlock_irqrestore(&sk->sk_receive_queue.lock, cpu_flags);
*seq = 0;
}
goto out;
}
/**
* llc_ui_sendmsg - Transmit data provided by the socket user.
* @sock: Socket to transmit data from.
* @msg: Various user related information.
* @len: Length of data to transmit.
*
* Transmit data provided by the socket user.
* Returns non-negative upon success, negative otherwise.
*/
static int llc_ui_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
{
struct sock *sk = sock->sk;
struct llc_sock *llc = llc_sk(sk);
DECLARE_SOCKADDR(struct sockaddr_llc *, addr, msg->msg_name);
int flags = msg->msg_flags;
int noblock = flags & MSG_DONTWAIT;
struct sk_buff *skb;
size_t size = 0;
int rc = -EINVAL, copied = 0, hdrlen;
dprintk("%s: sending from %02X to %02X\n", __func__,
llc->laddr.lsap, llc->daddr.lsap);
lock_sock(sk);
if (addr) {
if (msg->msg_namelen < sizeof(*addr))
goto release;
} else {
if (llc_ui_addr_null(&llc->addr))
goto release;
addr = &llc->addr;
}
/* must bind connection to sap if user hasn't done it. */
if (sock_flag(sk, SOCK_ZAPPED)) {
/* bind to sap with null dev, exclusive. */
rc = llc_ui_autobind(sock, addr);
if (rc)
goto release;
}
hdrlen = llc->dev->hard_header_len + llc_ui_header_len(sk, addr);
size = hdrlen + len;
if (size > llc->dev->mtu)
size = llc->dev->mtu;
copied = size - hdrlen;
release_sock(sk);
skb = sock_alloc_send_skb(sk, size, noblock, &rc);
lock_sock(sk);
if (!skb)
goto release;
skb->dev = llc->dev;
skb->protocol = llc_proto_type(addr->sllc_arphrd);
skb_reserve(skb, hdrlen);
rc = memcpy_from_msg(skb_put(skb, copied), msg, copied);
if (rc)
goto out;
if (sk->sk_type == SOCK_DGRAM || addr->sllc_ua) {
llc_build_and_send_ui_pkt(llc->sap, skb, addr->sllc_mac,
addr->sllc_sap);
goto out;
}
if (addr->sllc_test) {
llc_build_and_send_test_pkt(llc->sap, skb, addr->sllc_mac,
addr->sllc_sap);
goto out;
}
if (addr->sllc_xid) {
llc_build_and_send_xid_pkt(llc->sap, skb, addr->sllc_mac,
addr->sllc_sap);
goto out;
}
rc = -ENOPROTOOPT;
if (!(sk->sk_type == SOCK_STREAM && !addr->sllc_ua))
goto out;
rc = llc_ui_send_data(sk, skb, noblock);
out:
if (rc) {
kfree_skb(skb);
release:
dprintk("%s: failed sending from %02X to %02X: %d\n",
__func__, llc->laddr.lsap, llc->daddr.lsap, rc);
}
release_sock(sk);
return rc ? : copied;
}
/**
* llc_ui_getname - return the address info of a socket
* @sock: Socket to get address of.
* @uaddr: Address structure to return information.
* @uaddrlen: Length of address structure.
* @peer: Does user want local or remote address information.
*
* Return the address information of a socket.
*/
static int llc_ui_getname(struct socket *sock, struct sockaddr *uaddr,
int *uaddrlen, int peer)
{
struct sockaddr_llc sllc;
struct sock *sk = sock->sk;
struct llc_sock *llc = llc_sk(sk);
int rc = -EBADF;
memset(&sllc, 0, sizeof(sllc));
lock_sock(sk);
if (sock_flag(sk, SOCK_ZAPPED))
goto out;
*uaddrlen = sizeof(sllc);
if (peer) {
rc = -ENOTCONN;
if (sk->sk_state != TCP_ESTABLISHED)
goto out;
if(llc->dev)
sllc.sllc_arphrd = llc->dev->type;
sllc.sllc_sap = llc->daddr.lsap;
memcpy(&sllc.sllc_mac, &llc->daddr.mac, IFHWADDRLEN);
} else {
rc = -EINVAL;
if (!llc->sap)
goto out;
sllc.sllc_sap = llc->sap->laddr.lsap;
if (llc->dev) {
sllc.sllc_arphrd = llc->dev->type;
memcpy(&sllc.sllc_mac, llc->dev->dev_addr,
IFHWADDRLEN);
}
}
rc = 0;
sllc.sllc_family = AF_LLC;
memcpy(uaddr, &sllc, sizeof(sllc));
out:
release_sock(sk);
return rc;
}
/**
* llc_ui_ioctl - io controls for PF_LLC
* @sock: Socket to get/set info
* @cmd: command
* @arg: optional argument for cmd
*
* get/set info on llc sockets
*/
static int llc_ui_ioctl(struct socket *sock, unsigned int cmd,
unsigned long arg)
{
return -ENOIOCTLCMD;
}
/**
* llc_ui_setsockopt - set various connection specific parameters.
* @sock: Socket to set options on.
* @level: Socket level user is requesting operations on.
* @optname: Operation name.
* @optval: User provided operation data.
* @optlen: Length of optval.
*
* Set various connection specific parameters.
*/
static int llc_ui_setsockopt(struct socket *sock, int level, int optname,
char __user *optval, unsigned int optlen)
{
struct sock *sk = sock->sk;
struct llc_sock *llc = llc_sk(sk);
unsigned int opt;
int rc = -EINVAL;
lock_sock(sk);
if (unlikely(level != SOL_LLC || optlen != sizeof(int)))
goto out;
rc = get_user(opt, (int __user *)optval);
if (rc)
goto out;
rc = -EINVAL;
switch (optname) {
case LLC_OPT_RETRY:
if (opt > LLC_OPT_MAX_RETRY)
goto out;
llc->n2 = opt;
break;
case LLC_OPT_SIZE:
if (opt > LLC_OPT_MAX_SIZE)
goto out;
llc->n1 = opt;
break;
case LLC_OPT_ACK_TMR_EXP:
if (opt > LLC_OPT_MAX_ACK_TMR_EXP)
goto out;
llc->ack_timer.expire = opt * HZ;
break;
case LLC_OPT_P_TMR_EXP:
if (opt > LLC_OPT_MAX_P_TMR_EXP)
goto out;
llc->pf_cycle_timer.expire = opt * HZ;
break;
case LLC_OPT_REJ_TMR_EXP:
if (opt > LLC_OPT_MAX_REJ_TMR_EXP)
goto out;
llc->rej_sent_timer.expire = opt * HZ;
break;
case LLC_OPT_BUSY_TMR_EXP:
if (opt > LLC_OPT_MAX_BUSY_TMR_EXP)
goto out;
llc->busy_state_timer.expire = opt * HZ;
break;
case LLC_OPT_TX_WIN:
if (opt > LLC_OPT_MAX_WIN)
goto out;
llc->k = opt;
break;
case LLC_OPT_RX_WIN:
if (opt > LLC_OPT_MAX_WIN)
goto out;
llc->rw = opt;
break;
case LLC_OPT_PKTINFO:
if (opt)
llc->cmsg_flags |= LLC_CMSG_PKTINFO;
else
llc->cmsg_flags &= ~LLC_CMSG_PKTINFO;
break;
default:
rc = -ENOPROTOOPT;
goto out;
}
rc = 0;
out:
release_sock(sk);
return rc;
}
/**
* llc_ui_getsockopt - get connection specific socket info
* @sock: Socket to get information from.
* @level: Socket level user is requesting operations on.
* @optname: Operation name.
* @optval: Variable to return operation data in.
* @optlen: Length of optval.
*
* Get connection specific socket information.
*/
static int llc_ui_getsockopt(struct socket *sock, int level, int optname,
char __user *optval, int __user *optlen)
{
struct sock *sk = sock->sk;
struct llc_sock *llc = llc_sk(sk);
int val = 0, len = 0, rc = -EINVAL;
lock_sock(sk);
if (unlikely(level != SOL_LLC))
goto out;
rc = get_user(len, optlen);
if (rc)
goto out;
rc = -EINVAL;
if (len != sizeof(int))
goto out;
switch (optname) {
case LLC_OPT_RETRY:
val = llc->n2; break;
case LLC_OPT_SIZE:
val = llc->n1; break;
case LLC_OPT_ACK_TMR_EXP:
val = llc->ack_timer.expire / HZ; break;
case LLC_OPT_P_TMR_EXP:
val = llc->pf_cycle_timer.expire / HZ; break;
case LLC_OPT_REJ_TMR_EXP:
val = llc->rej_sent_timer.expire / HZ; break;
case LLC_OPT_BUSY_TMR_EXP:
val = llc->busy_state_timer.expire / HZ; break;
case LLC_OPT_TX_WIN:
val = llc->k; break;
case LLC_OPT_RX_WIN:
val = llc->rw; break;
case LLC_OPT_PKTINFO:
val = (llc->cmsg_flags & LLC_CMSG_PKTINFO) != 0;
break;
default:
rc = -ENOPROTOOPT;
goto out;
}
rc = 0;
if (put_user(len, optlen) || copy_to_user(optval, &val, len))
rc = -EFAULT;
out:
release_sock(sk);
return rc;
}
static const struct net_proto_family llc_ui_family_ops = {
.family = PF_LLC,
.create = llc_ui_create,
.owner = THIS_MODULE,
};
static const struct proto_ops llc_ui_ops = {
.family = PF_LLC,
.owner = THIS_MODULE,
.release = llc_ui_release,
.bind = llc_ui_bind,
.connect = llc_ui_connect,
.socketpair = sock_no_socketpair,
.accept = llc_ui_accept,
.getname = llc_ui_getname,
.poll = datagram_poll,
.ioctl = llc_ui_ioctl,
.listen = llc_ui_listen,
.shutdown = llc_ui_shutdown,
.setsockopt = llc_ui_setsockopt,
.getsockopt = llc_ui_getsockopt,
.sendmsg = llc_ui_sendmsg,
.recvmsg = llc_ui_recvmsg,
.mmap = sock_no_mmap,
.sendpage = sock_no_sendpage,
};
static const char llc_proc_err_msg[] __initconst =
KERN_CRIT "LLC: Unable to register the proc_fs entries\n";
static const char llc_sysctl_err_msg[] __initconst =
KERN_CRIT "LLC: Unable to register the sysctl entries\n";
static const char llc_sock_err_msg[] __initconst =
KERN_CRIT "LLC: Unable to register the network family\n";
static int __init llc2_init(void)
{
int rc = proto_register(&llc_proto, 0);
if (rc != 0)
goto out;
llc_build_offset_table();
llc_station_init();
llc_ui_sap_last_autoport = LLC_SAP_DYN_START;
rc = llc_proc_init();
if (rc != 0) {
printk(llc_proc_err_msg);
goto out_station;
}
rc = llc_sysctl_init();
if (rc) {
printk(llc_sysctl_err_msg);
goto out_proc;
}
rc = sock_register(&llc_ui_family_ops);
if (rc) {
printk(llc_sock_err_msg);
goto out_sysctl;
}
llc_add_pack(LLC_DEST_SAP, llc_sap_handler);
llc_add_pack(LLC_DEST_CONN, llc_conn_handler);
out:
return rc;
out_sysctl:
llc_sysctl_exit();
out_proc:
llc_proc_exit();
out_station:
llc_station_exit();
proto_unregister(&llc_proto);
goto out;
}
static void __exit llc2_exit(void)
{
llc_station_exit();
llc_remove_pack(LLC_DEST_SAP);
llc_remove_pack(LLC_DEST_CONN);
sock_unregister(PF_LLC);
llc_proc_exit();
llc_sysctl_exit();
proto_unregister(&llc_proto);
}
module_init(llc2_init);
module_exit(llc2_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Procom 1997, Jay Schullist 2001, Arnaldo C. Melo 2001-2003");
MODULE_DESCRIPTION("IEEE 802.2 PF_LLC support");
MODULE_ALIAS_NETPROTO(PF_LLC);
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