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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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5aac493787
The barriers are unneeded; wait_woken() and woken_wake_function() already provide us with the required synchronization: remove them and document that we're relying on the (implicit) synchronization provided by wait_woken() and woken_wake_function(). Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com> Reviewed-by: Brian Norris <computersforpeace@gmail.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
516 lines
11 KiB
C
516 lines
11 KiB
C
/*
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CMTP implementation for Linux Bluetooth stack (BlueZ).
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Copyright (C) 2002-2003 Marcel Holtmann <marcel@holtmann.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License version 2 as
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published by the Free Software Foundation;
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.
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IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) AND AUTHOR(S) BE LIABLE FOR ANY
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CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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ALL LIABILITY, INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PATENTS,
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COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS, RELATING TO USE OF THIS
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SOFTWARE IS DISCLAIMED.
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*/
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/poll.h>
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#include <linux/fcntl.h>
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#include <linux/freezer.h>
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#include <linux/skbuff.h>
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#include <linux/socket.h>
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#include <linux/ioctl.h>
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#include <linux/file.h>
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#include <linux/init.h>
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#include <linux/kthread.h>
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#include <net/sock.h>
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#include <linux/isdn/capilli.h>
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#include <net/bluetooth/bluetooth.h>
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#include <net/bluetooth/l2cap.h>
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#include "cmtp.h"
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#define VERSION "1.0"
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static DECLARE_RWSEM(cmtp_session_sem);
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static LIST_HEAD(cmtp_session_list);
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static struct cmtp_session *__cmtp_get_session(bdaddr_t *bdaddr)
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{
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struct cmtp_session *session;
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BT_DBG("");
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list_for_each_entry(session, &cmtp_session_list, list)
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if (!bacmp(bdaddr, &session->bdaddr))
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return session;
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return NULL;
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}
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static void __cmtp_link_session(struct cmtp_session *session)
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{
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list_add(&session->list, &cmtp_session_list);
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}
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static void __cmtp_unlink_session(struct cmtp_session *session)
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{
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list_del(&session->list);
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}
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static void __cmtp_copy_session(struct cmtp_session *session, struct cmtp_conninfo *ci)
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{
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u32 valid_flags = BIT(CMTP_LOOPBACK);
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memset(ci, 0, sizeof(*ci));
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bacpy(&ci->bdaddr, &session->bdaddr);
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ci->flags = session->flags & valid_flags;
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ci->state = session->state;
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ci->num = session->num;
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}
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static inline int cmtp_alloc_block_id(struct cmtp_session *session)
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{
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int i, id = -1;
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for (i = 0; i < 16; i++)
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if (!test_and_set_bit(i, &session->blockids)) {
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id = i;
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break;
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}
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return id;
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}
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static inline void cmtp_free_block_id(struct cmtp_session *session, int id)
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{
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clear_bit(id, &session->blockids);
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}
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static inline void cmtp_add_msgpart(struct cmtp_session *session, int id, const unsigned char *buf, int count)
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{
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struct sk_buff *skb = session->reassembly[id], *nskb;
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int size;
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BT_DBG("session %p buf %p count %d", session, buf, count);
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size = (skb) ? skb->len + count : count;
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nskb = alloc_skb(size, GFP_ATOMIC);
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if (!nskb) {
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BT_ERR("Can't allocate memory for CAPI message");
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return;
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}
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if (skb && (skb->len > 0))
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skb_copy_from_linear_data(skb, skb_put(nskb, skb->len), skb->len);
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skb_put_data(nskb, buf, count);
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session->reassembly[id] = nskb;
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kfree_skb(skb);
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}
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static inline int cmtp_recv_frame(struct cmtp_session *session, struct sk_buff *skb)
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{
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__u8 hdr, hdrlen, id;
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__u16 len;
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BT_DBG("session %p skb %p len %d", session, skb, skb->len);
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while (skb->len > 0) {
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hdr = skb->data[0];
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switch (hdr & 0xc0) {
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case 0x40:
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hdrlen = 2;
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len = skb->data[1];
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break;
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case 0x80:
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hdrlen = 3;
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len = skb->data[1] | (skb->data[2] << 8);
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break;
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default:
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hdrlen = 1;
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len = 0;
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break;
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}
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id = (hdr & 0x3c) >> 2;
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BT_DBG("hdr 0x%02x hdrlen %d len %d id %d", hdr, hdrlen, len, id);
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if (hdrlen + len > skb->len) {
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BT_ERR("Wrong size or header information in CMTP frame");
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break;
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}
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if (len == 0) {
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skb_pull(skb, hdrlen);
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continue;
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}
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switch (hdr & 0x03) {
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case 0x00:
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cmtp_add_msgpart(session, id, skb->data + hdrlen, len);
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cmtp_recv_capimsg(session, session->reassembly[id]);
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session->reassembly[id] = NULL;
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break;
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case 0x01:
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cmtp_add_msgpart(session, id, skb->data + hdrlen, len);
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break;
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default:
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kfree_skb(session->reassembly[id]);
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session->reassembly[id] = NULL;
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break;
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}
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skb_pull(skb, hdrlen + len);
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}
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kfree_skb(skb);
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return 0;
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}
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static int cmtp_send_frame(struct cmtp_session *session, unsigned char *data, int len)
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{
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struct socket *sock = session->sock;
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struct kvec iv = { data, len };
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struct msghdr msg;
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BT_DBG("session %p data %p len %d", session, data, len);
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if (!len)
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return 0;
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memset(&msg, 0, sizeof(msg));
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return kernel_sendmsg(sock, &msg, &iv, 1, len);
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}
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static void cmtp_process_transmit(struct cmtp_session *session)
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{
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struct sk_buff *skb, *nskb;
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unsigned char *hdr;
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unsigned int size, tail;
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BT_DBG("session %p", session);
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nskb = alloc_skb(session->mtu, GFP_ATOMIC);
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if (!nskb) {
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BT_ERR("Can't allocate memory for new frame");
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return;
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}
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while ((skb = skb_dequeue(&session->transmit))) {
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struct cmtp_scb *scb = (void *) skb->cb;
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tail = session->mtu - nskb->len;
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if (tail < 5) {
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cmtp_send_frame(session, nskb->data, nskb->len);
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skb_trim(nskb, 0);
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tail = session->mtu;
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}
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size = min_t(uint, ((tail < 258) ? (tail - 2) : (tail - 3)), skb->len);
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if (scb->id < 0) {
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scb->id = cmtp_alloc_block_id(session);
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if (scb->id < 0) {
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skb_queue_head(&session->transmit, skb);
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break;
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}
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}
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if (size < 256) {
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hdr = skb_put(nskb, 2);
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hdr[0] = 0x40
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| ((scb->id << 2) & 0x3c)
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| ((skb->len == size) ? 0x00 : 0x01);
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hdr[1] = size;
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} else {
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hdr = skb_put(nskb, 3);
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hdr[0] = 0x80
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| ((scb->id << 2) & 0x3c)
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| ((skb->len == size) ? 0x00 : 0x01);
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hdr[1] = size & 0xff;
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hdr[2] = size >> 8;
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}
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skb_copy_from_linear_data(skb, skb_put(nskb, size), size);
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skb_pull(skb, size);
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if (skb->len > 0) {
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skb_queue_head(&session->transmit, skb);
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} else {
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cmtp_free_block_id(session, scb->id);
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if (scb->data) {
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cmtp_send_frame(session, nskb->data, nskb->len);
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skb_trim(nskb, 0);
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}
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kfree_skb(skb);
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}
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}
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cmtp_send_frame(session, nskb->data, nskb->len);
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kfree_skb(nskb);
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}
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static int cmtp_session(void *arg)
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{
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struct cmtp_session *session = arg;
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struct sock *sk = session->sock->sk;
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struct sk_buff *skb;
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DEFINE_WAIT_FUNC(wait, woken_wake_function);
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BT_DBG("session %p", session);
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set_user_nice(current, -15);
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add_wait_queue(sk_sleep(sk), &wait);
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while (1) {
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if (atomic_read(&session->terminate))
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break;
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if (sk->sk_state != BT_CONNECTED)
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break;
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while ((skb = skb_dequeue(&sk->sk_receive_queue))) {
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skb_orphan(skb);
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if (!skb_linearize(skb))
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cmtp_recv_frame(session, skb);
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else
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kfree_skb(skb);
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}
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cmtp_process_transmit(session);
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/*
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* wait_woken() performs the necessary memory barriers
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* for us; see the header comment for this primitive.
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*/
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wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
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}
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remove_wait_queue(sk_sleep(sk), &wait);
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down_write(&cmtp_session_sem);
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if (!(session->flags & BIT(CMTP_LOOPBACK)))
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cmtp_detach_device(session);
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fput(session->sock->file);
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__cmtp_unlink_session(session);
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up_write(&cmtp_session_sem);
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kfree(session);
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module_put_and_exit(0);
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return 0;
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}
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int cmtp_add_connection(struct cmtp_connadd_req *req, struct socket *sock)
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{
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u32 valid_flags = BIT(CMTP_LOOPBACK);
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struct cmtp_session *session, *s;
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int i, err;
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BT_DBG("");
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if (!l2cap_is_socket(sock))
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return -EBADFD;
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if (req->flags & ~valid_flags)
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return -EINVAL;
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session = kzalloc(sizeof(struct cmtp_session), GFP_KERNEL);
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if (!session)
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return -ENOMEM;
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down_write(&cmtp_session_sem);
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s = __cmtp_get_session(&l2cap_pi(sock->sk)->chan->dst);
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if (s && s->state == BT_CONNECTED) {
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err = -EEXIST;
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goto failed;
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}
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bacpy(&session->bdaddr, &l2cap_pi(sock->sk)->chan->dst);
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session->mtu = min_t(uint, l2cap_pi(sock->sk)->chan->omtu,
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l2cap_pi(sock->sk)->chan->imtu);
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BT_DBG("mtu %d", session->mtu);
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sprintf(session->name, "%pMR", &session->bdaddr);
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session->sock = sock;
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session->state = BT_CONFIG;
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init_waitqueue_head(&session->wait);
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session->msgnum = CMTP_INITIAL_MSGNUM;
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INIT_LIST_HEAD(&session->applications);
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skb_queue_head_init(&session->transmit);
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for (i = 0; i < 16; i++)
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session->reassembly[i] = NULL;
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session->flags = req->flags;
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__cmtp_link_session(session);
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__module_get(THIS_MODULE);
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session->task = kthread_run(cmtp_session, session, "kcmtpd_ctr_%d",
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session->num);
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if (IS_ERR(session->task)) {
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module_put(THIS_MODULE);
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err = PTR_ERR(session->task);
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goto unlink;
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}
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if (!(session->flags & BIT(CMTP_LOOPBACK))) {
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err = cmtp_attach_device(session);
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if (err < 0) {
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atomic_inc(&session->terminate);
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wake_up_interruptible(sk_sleep(session->sock->sk));
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up_write(&cmtp_session_sem);
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return err;
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}
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}
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up_write(&cmtp_session_sem);
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return 0;
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unlink:
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__cmtp_unlink_session(session);
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failed:
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up_write(&cmtp_session_sem);
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kfree(session);
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return err;
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}
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int cmtp_del_connection(struct cmtp_conndel_req *req)
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{
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u32 valid_flags = 0;
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struct cmtp_session *session;
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int err = 0;
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BT_DBG("");
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if (req->flags & ~valid_flags)
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return -EINVAL;
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down_read(&cmtp_session_sem);
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session = __cmtp_get_session(&req->bdaddr);
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if (session) {
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/* Flush the transmit queue */
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skb_queue_purge(&session->transmit);
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/* Stop session thread */
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atomic_inc(&session->terminate);
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/*
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* See the comment preceding the call to wait_woken()
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* in cmtp_session().
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*/
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wake_up_interruptible(sk_sleep(session->sock->sk));
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} else
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err = -ENOENT;
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up_read(&cmtp_session_sem);
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return err;
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}
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int cmtp_get_connlist(struct cmtp_connlist_req *req)
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{
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struct cmtp_session *session;
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int err = 0, n = 0;
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BT_DBG("");
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down_read(&cmtp_session_sem);
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list_for_each_entry(session, &cmtp_session_list, list) {
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struct cmtp_conninfo ci;
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__cmtp_copy_session(session, &ci);
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if (copy_to_user(req->ci, &ci, sizeof(ci))) {
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err = -EFAULT;
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break;
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}
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if (++n >= req->cnum)
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break;
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req->ci++;
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}
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req->cnum = n;
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up_read(&cmtp_session_sem);
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return err;
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}
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int cmtp_get_conninfo(struct cmtp_conninfo *ci)
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{
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struct cmtp_session *session;
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int err = 0;
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down_read(&cmtp_session_sem);
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session = __cmtp_get_session(&ci->bdaddr);
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if (session)
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__cmtp_copy_session(session, ci);
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else
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err = -ENOENT;
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up_read(&cmtp_session_sem);
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return err;
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}
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static int __init cmtp_init(void)
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{
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BT_INFO("CMTP (CAPI Emulation) ver %s", VERSION);
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cmtp_init_sockets();
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return 0;
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}
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static void __exit cmtp_exit(void)
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{
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cmtp_cleanup_sockets();
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}
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module_init(cmtp_init);
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module_exit(cmtp_exit);
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MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
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MODULE_DESCRIPTION("Bluetooth CMTP ver " VERSION);
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MODULE_VERSION(VERSION);
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("bt-proto-5");
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