path: root/net/llc/af_llc.c

/*
 * 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 <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 int 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 (!capable(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);
		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,</