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af_llc.c
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af_llc.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...) do {} while (0)
#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)
rc = LLC_PDU_LEN_U;
else if (addr->sllc_xid)
/* We need to expand header to sizeof(struct llc_xid_info)
* since llc_pdu_init_as_xid_cmd() sets 4,5,6 bytes of LLC header
* as XID PDU. In llc_ui_sendmsg() we reserved header size and then
* filled all other space with user data. If we won't reserve this
* bytes, llc_pdu_init_as_xid_cmd() will overwrite user data
*/
rc = LLC_PDU_LEN_U_XID;
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.
*
* This function always consumes a reference to the skb.
*/
static int llc_ui_send_data(struct sock* sk, struct sk_buff *skb, int noblock)
{
struct llc_sock* llc = llc_sk(sk);
if (unlikely(llc_data_accept_state(llc->state) ||
llc->remote_busy_flag ||
llc->p_flag)) {
long timeout = sock_sndtimeo(sk, noblock);
int rc;
rc = llc_ui_wait_for_busy_core(sk, timeout);
if (rc) {
kfree_skb(skb);
return rc;
}
}
return llc_build_and_send_pkt(sk, skb);
}
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_TYPESAFE_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)) {
struct llc_sap *sap = llc->sap;
/* Hold this for release_sock(), so that llc_backlog_rcv()
* could still use it.
*/
llc_sap_hold(sap);
llc_sap_remove_socket(llc->sap, sk);
release_sock(sk);
llc_sap_put(sap);
} else {
release_sock(sk);
}
netdev_put(llc->dev, &llc->dev_tracker);
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 net_device *dev = NULL;
struct llc_sap *sap;
int rc = -EINVAL;
if (!sock_flag(sk, SOCK_ZAPPED))
goto out;
if (!addr->sllc_arphrd)
addr->sllc_arphrd = ARPHRD_ETHER;
if (addr->sllc_arphrd != ARPHRD_ETHER)
goto out;
rc = -ENODEV;
if (sk->sk_bound_dev_if) {
dev = dev_get_by_index(&init_net, sk->sk_bound_dev_if);
if (dev && addr->sllc_arphrd != dev->type) {
dev_put(dev);
dev = NULL;
}
} else
dev = dev_getfirstbyhwtype(&init_net, addr->sllc_arphrd);
if (!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;
/* Note: We do not expect errors from this point. */
llc->dev = dev;
netdev_tracker_alloc(llc->dev, &llc->dev_tracker, GFP_KERNEL);
dev = NULL;
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:
dev_put(dev);
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 net_device *dev = NULL;
struct llc_sap *sap;
int rc = -EINVAL;
lock_sock(sk);
if (unlikely(!sock_flag(sk, SOCK_ZAPPED) || addrlen != sizeof(*addr)))
goto out;
rc = -EAFNOSUPPORT;
if (!addr->sllc_arphrd)
addr->sllc_arphrd = ARPHRD_ETHER;
if (unlikely(addr->sllc_family != AF_LLC || addr->sllc_arphrd != ARPHRD_ETHER))
goto out;
dprintk("%s: binding %02X\n", __func__, addr->sllc_sap);
rc = -ENODEV;
rcu_read_lock();
if (sk->sk_bound_dev_if) {
dev = dev_get_by_index_rcu(&init_net, sk->sk_bound_dev_if);
if (dev) {
if (is_zero_ether_addr(addr->sllc_mac))
memcpy(addr->sllc_mac, dev->dev_addr,
IFHWADDRLEN);
if (addr->sllc_arphrd != dev->type ||
!ether_addr_equal(addr->sllc_mac,
dev->dev_addr)) {
rc = -EINVAL;
dev = NULL;
}
}
} else {
dev = dev_getbyhwaddr_rcu(&init_net, addr->sllc_arphrd,
addr->sllc_mac);
}
dev_hold(dev);
rcu_read_unlock();
if (!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, &init_net);
if (ask) {
sock_put(ask);
goto out_put;
}
}
/* Note: We do not expect errors from this point. */
llc->dev = dev;
netdev_tracker_alloc(llc->dev, &llc->dev_tracker, GFP_KERNEL);
dev = NULL;
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:
dev_put(dev);
release_sock(sk);
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,
READ_ONCE(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,
READ_ONCE(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,
(READ_ONCE(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_acceptq_removed(sk);
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);
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 && !READ_ONCE(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)) {
skb_unlink(skb, &sk->sk_receive_queue);
kfree_skb(skb);
*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)) {
skb_unlink(skb, &sk->sk_receive_queue);
kfree_skb(skb);
*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)
{
DECLARE_SOCKADDR(struct sockaddr_llc *, addr, msg->msg_name);
struct sock *sk = sock->sk;
struct llc_sock *llc = llc_sk(sk);
int flags = msg->msg_flags;
int noblock = flags & MSG_DONTWAIT;
int rc = -EINVAL, copied = 0, hdrlen, hh_len;
struct sk_buff *skb = NULL;
struct net_device *dev;
size_t size = 0;
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 out;
} else {
if (llc_ui_addr_null(&llc->addr))
goto out;
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 out;
}
dev = llc->dev;
hh_len = LL_RESERVED_SPACE(dev);
hdrlen = llc_ui_header_len(sk, addr);
size = hdrlen + len;
size = min_t(size_t, size, READ_ONCE(dev->mtu));
copied = size - hdrlen;
rc = -EINVAL;
if (copied < 0)
goto out;
release_sock(sk);
skb = sock_alloc_send_skb(sk, hh_len + size, noblock, &rc);
lock_sock(sk);
if (!skb)
goto out;
if (sock_flag(sk, SOCK_ZAPPED) ||
llc->dev != dev ||
hdrlen != llc_ui_header_len(sk, addr) ||
hh_len != LL_RESERVED_SPACE(dev) ||
size > READ_ONCE(dev->mtu))
goto out;
skb->dev = dev;
skb->protocol = llc_proto_type(addr->sllc_arphrd);
skb_reserve(skb, hh_len + 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);
skb = NULL;
goto out;
}
if (addr->sllc_test) {
llc_build_and_send_test_pkt(llc->sap, skb, addr->sllc_mac,
addr->sllc_sap);
skb = NULL;
goto out;
}
if (addr->sllc_xid) {
llc_build_and_send_xid_pkt(llc->sap, skb, addr->sllc_mac,
addr->sllc_sap);
skb = NULL;