summaryrefslogtreecommitdiffstats
path: root/net/caif/caif_socket.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/caif/caif_socket.c')
-rw-r--r--net/caif/caif_socket.c1113
1 files changed, 1113 insertions, 0 deletions
diff --git a/net/caif/caif_socket.c b/net/caif/caif_socket.c
new file mode 100644
index 0000000000..9c82698da4
--- /dev/null
+++ b/net/caif/caif_socket.c
@@ -0,0 +1,1113 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) ST-Ericsson AB 2010
+ * Author: Sjur Brendeland
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
+
+#include <linux/filter.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/sched/signal.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include <linux/list.h>
+#include <linux/wait.h>
+#include <linux/poll.h>
+#include <linux/tcp.h>
+#include <linux/uaccess.h>
+#include <linux/debugfs.h>
+#include <linux/caif/caif_socket.h>
+#include <linux/pkt_sched.h>
+#include <net/sock.h>
+#include <net/tcp_states.h>
+#include <net/caif/caif_layer.h>
+#include <net/caif/caif_dev.h>
+#include <net/caif/cfpkt.h>
+
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_NETPROTO(AF_CAIF);
+
+/*
+ * CAIF state is re-using the TCP socket states.
+ * caif_states stored in sk_state reflect the state as reported by
+ * the CAIF stack, while sk_socket->state is the state of the socket.
+ */
+enum caif_states {
+ CAIF_CONNECTED = TCP_ESTABLISHED,
+ CAIF_CONNECTING = TCP_SYN_SENT,
+ CAIF_DISCONNECTED = TCP_CLOSE
+};
+
+#define TX_FLOW_ON_BIT 1
+#define RX_FLOW_ON_BIT 2
+
+struct caifsock {
+ struct sock sk; /* must be first member */
+ struct cflayer layer;
+ unsigned long flow_state;
+ struct caif_connect_request conn_req;
+ struct mutex readlock;
+ struct dentry *debugfs_socket_dir;
+ int headroom, tailroom, maxframe;
+};
+
+static int rx_flow_is_on(struct caifsock *cf_sk)
+{
+ return test_bit(RX_FLOW_ON_BIT, &cf_sk->flow_state);
+}
+
+static int tx_flow_is_on(struct caifsock *cf_sk)
+{
+ return test_bit(TX_FLOW_ON_BIT, &cf_sk->flow_state);
+}
+
+static void set_rx_flow_off(struct caifsock *cf_sk)
+{
+ clear_bit(RX_FLOW_ON_BIT, &cf_sk->flow_state);
+}
+
+static void set_rx_flow_on(struct caifsock *cf_sk)
+{
+ set_bit(RX_FLOW_ON_BIT, &cf_sk->flow_state);
+}
+
+static void set_tx_flow_off(struct caifsock *cf_sk)
+{
+ clear_bit(TX_FLOW_ON_BIT, &cf_sk->flow_state);
+}
+
+static void set_tx_flow_on(struct caifsock *cf_sk)
+{
+ set_bit(TX_FLOW_ON_BIT, &cf_sk->flow_state);
+}
+
+static void caif_read_lock(struct sock *sk)
+{
+ struct caifsock *cf_sk;
+ cf_sk = container_of(sk, struct caifsock, sk);
+ mutex_lock(&cf_sk->readlock);
+}
+
+static void caif_read_unlock(struct sock *sk)
+{
+ struct caifsock *cf_sk;
+ cf_sk = container_of(sk, struct caifsock, sk);
+ mutex_unlock(&cf_sk->readlock);
+}
+
+static int sk_rcvbuf_lowwater(struct caifsock *cf_sk)
+{
+ /* A quarter of full buffer is used a low water mark */
+ return cf_sk->sk.sk_rcvbuf / 4;
+}
+
+static void caif_flow_ctrl(struct sock *sk, int mode)
+{
+ struct caifsock *cf_sk;
+ cf_sk = container_of(sk, struct caifsock, sk);
+ if (cf_sk->layer.dn && cf_sk->layer.dn->modemcmd)
+ cf_sk->layer.dn->modemcmd(cf_sk->layer.dn, mode);
+}
+
+/*
+ * Copied from sock.c:sock_queue_rcv_skb(), but changed so packets are
+ * not dropped, but CAIF is sending flow off instead.
+ */
+static void caif_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
+{
+ int err;
+ unsigned long flags;
+ struct sk_buff_head *list = &sk->sk_receive_queue;
+ struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
+ bool queued = false;
+
+ if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
+ (unsigned int)sk->sk_rcvbuf && rx_flow_is_on(cf_sk)) {
+ net_dbg_ratelimited("sending flow OFF (queue len = %d %d)\n",
+ atomic_read(&cf_sk->sk.sk_rmem_alloc),
+ sk_rcvbuf_lowwater(cf_sk));
+ set_rx_flow_off(cf_sk);
+ caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
+ }
+
+ err = sk_filter(sk, skb);
+ if (err)
+ goto out;
+
+ if (!sk_rmem_schedule(sk, skb, skb->truesize) && rx_flow_is_on(cf_sk)) {
+ set_rx_flow_off(cf_sk);
+ net_dbg_ratelimited("sending flow OFF due to rmem_schedule\n");
+ caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
+ }
+ skb->dev = NULL;
+ skb_set_owner_r(skb, sk);
+ spin_lock_irqsave(&list->lock, flags);
+ queued = !sock_flag(sk, SOCK_DEAD);
+ if (queued)
+ __skb_queue_tail(list, skb);
+ spin_unlock_irqrestore(&list->lock, flags);
+out:
+ if (queued)
+ sk->sk_data_ready(sk);
+ else
+ kfree_skb(skb);
+}
+
+/* Packet Receive Callback function called from CAIF Stack */
+static int caif_sktrecv_cb(struct cflayer *layr, struct cfpkt *pkt)
+{
+ struct caifsock *cf_sk;
+ struct sk_buff *skb;
+
+ cf_sk = container_of(layr, struct caifsock, layer);
+ skb = cfpkt_tonative(pkt);
+
+ if (unlikely(cf_sk->sk.sk_state != CAIF_CONNECTED)) {
+ kfree_skb(skb);
+ return 0;
+ }
+ caif_queue_rcv_skb(&cf_sk->sk, skb);
+ return 0;
+}
+
+static void cfsk_hold(struct cflayer *layr)
+{
+ struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
+ sock_hold(&cf_sk->sk);
+}
+
+static void cfsk_put(struct cflayer *layr)
+{
+ struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
+ sock_put(&cf_sk->sk);
+}
+
+/* Packet Control Callback function called from CAIF */
+static void caif_ctrl_cb(struct cflayer *layr,
+ enum caif_ctrlcmd flow,
+ int phyid)
+{
+ struct caifsock *cf_sk = container_of(layr, struct caifsock, layer);
+ switch (flow) {
+ case CAIF_CTRLCMD_FLOW_ON_IND:
+ /* OK from modem to start sending again */
+ set_tx_flow_on(cf_sk);
+ cf_sk->sk.sk_state_change(&cf_sk->sk);
+ break;
+
+ case CAIF_CTRLCMD_FLOW_OFF_IND:
+ /* Modem asks us to shut up */
+ set_tx_flow_off(cf_sk);
+ cf_sk->sk.sk_state_change(&cf_sk->sk);
+ break;
+
+ case CAIF_CTRLCMD_INIT_RSP:
+ /* We're now connected */
+ caif_client_register_refcnt(&cf_sk->layer,
+ cfsk_hold, cfsk_put);
+ cf_sk->sk.sk_state = CAIF_CONNECTED;
+ set_tx_flow_on(cf_sk);
+ cf_sk->sk.sk_shutdown = 0;
+ cf_sk->sk.sk_state_change(&cf_sk->sk);
+ break;
+
+ case CAIF_CTRLCMD_DEINIT_RSP:
+ /* We're now disconnected */
+ cf_sk->sk.sk_state = CAIF_DISCONNECTED;
+ cf_sk->sk.sk_state_change(&cf_sk->sk);
+ break;
+
+ case CAIF_CTRLCMD_INIT_FAIL_RSP:
+ /* Connect request failed */
+ cf_sk->sk.sk_err = ECONNREFUSED;
+ cf_sk->sk.sk_state = CAIF_DISCONNECTED;
+ cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
+ /*
+ * Socket "standards" seems to require POLLOUT to
+ * be set at connect failure.
+ */
+ set_tx_flow_on(cf_sk);
+ cf_sk->sk.sk_state_change(&cf_sk->sk);
+ break;
+
+ case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
+ /* Modem has closed this connection, or device is down. */
+ cf_sk->sk.sk_shutdown = SHUTDOWN_MASK;
+ cf_sk->sk.sk_err = ECONNRESET;
+ set_rx_flow_on(cf_sk);
+ sk_error_report(&cf_sk->sk);
+ break;
+
+ default:
+ pr_debug("Unexpected flow command %d\n", flow);
+ }
+}
+
+static void caif_check_flow_release(struct sock *sk)
+{
+ struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
+
+ if (rx_flow_is_on(cf_sk))
+ return;
+
+ if (atomic_read(&sk->sk_rmem_alloc) <= sk_rcvbuf_lowwater(cf_sk)) {
+ set_rx_flow_on(cf_sk);
+ caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_ON_REQ);
+ }
+}
+
+/*
+ * Copied from unix_dgram_recvmsg, but removed credit checks,
+ * changed locking, address handling and added MSG_TRUNC.
+ */
+static int caif_seqpkt_recvmsg(struct socket *sock, struct msghdr *m,
+ size_t len, int flags)
+
+{
+ struct sock *sk = sock->sk;
+ struct sk_buff *skb;
+ int ret;
+ int copylen;
+
+ ret = -EOPNOTSUPP;
+ if (flags & MSG_OOB)
+ goto read_error;
+
+ skb = skb_recv_datagram(sk, flags, &ret);
+ if (!skb)
+ goto read_error;
+ copylen = skb->len;
+ if (len < copylen) {
+ m->msg_flags |= MSG_TRUNC;
+ copylen = len;
+ }
+
+ ret = skb_copy_datagram_msg(skb, 0, m, copylen);
+ if (ret)
+ goto out_free;
+
+ ret = (flags & MSG_TRUNC) ? skb->len : copylen;
+out_free:
+ skb_free_datagram(sk, skb);
+ caif_check_flow_release(sk);
+ return ret;
+
+read_error:
+ return ret;
+}
+
+
+/* Copied from unix_stream_wait_data, identical except for lock call. */
+static long caif_stream_data_wait(struct sock *sk, long timeo)
+{
+ DEFINE_WAIT(wait);
+ lock_sock(sk);
+
+ for (;;) {
+ prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
+
+ if (!skb_queue_empty(&sk->sk_receive_queue) ||
+ sk->sk_err ||
+ sk->sk_state != CAIF_CONNECTED ||
+ sock_flag(sk, SOCK_DEAD) ||
+ (sk->sk_shutdown & RCV_SHUTDOWN) ||
+ signal_pending(current) ||
+ !timeo)
+ break;
+
+ sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
+ release_sock(sk);
+ timeo = schedule_timeout(timeo);
+ lock_sock(sk);
+
+ if (sock_flag(sk, SOCK_DEAD))
+ break;
+
+ sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
+ }
+
+ finish_wait(sk_sleep(sk), &wait);
+ release_sock(sk);
+ return timeo;
+}
+
+
+/*
+ * Copied from unix_stream_recvmsg, but removed credit checks,
+ * changed locking calls, changed address handling.
+ */
+static int caif_stream_recvmsg(struct socket *sock, struct msghdr *msg,
+ size_t size, int flags)
+{
+ struct sock *sk = sock->sk;
+ int copied = 0;
+ int target;
+ int err = 0;
+ long timeo;
+
+ err = -EOPNOTSUPP;
+ if (flags&MSG_OOB)
+ goto out;
+
+ /*
+ * Lock the socket to prevent queue disordering
+ * while sleeps in memcpy_tomsg
+ */
+ err = -EAGAIN;
+ if (sk->sk_state == CAIF_CONNECTING)
+ goto out;
+
+ caif_read_lock(sk);
+ target = sock_rcvlowat(sk, flags&MSG_WAITALL, size);
+ timeo = sock_rcvtimeo(sk, flags&MSG_DONTWAIT);
+
+ do {
+ int chunk;
+ struct sk_buff *skb;
+
+ lock_sock(sk);
+ if (sock_flag(sk, SOCK_DEAD)) {
+ err = -ECONNRESET;
+ goto unlock;
+ }
+ skb = skb_dequeue(&sk->sk_receive_queue);
+ caif_check_flow_release(sk);
+
+ if (skb == NULL) {
+ if (copied >= target)
+ goto unlock;
+ /*
+ * POSIX 1003.1g mandates this order.
+ */
+ err = sock_error(sk);
+ if (err)
+ goto unlock;
+ err = -ECONNRESET;
+ if (sk->sk_shutdown & RCV_SHUTDOWN)
+ goto unlock;
+
+ err = -EPIPE;
+ if (sk->sk_state != CAIF_CONNECTED)
+ goto unlock;
+ if (sock_flag(sk, SOCK_DEAD))
+ goto unlock;
+
+ release_sock(sk);
+
+ err = -EAGAIN;
+ if (!timeo)
+ break;
+
+ caif_read_unlock(sk);
+
+ timeo = caif_stream_data_wait(sk, timeo);
+
+ if (signal_pending(current)) {
+ err = sock_intr_errno(timeo);
+ goto out;
+ }
+ caif_read_lock(sk);
+ continue;
+unlock:
+ release_sock(sk);
+ break;
+ }
+ release_sock(sk);
+ chunk = min_t(unsigned int, skb->len, size);
+ if (memcpy_to_msg(msg, skb->data, chunk)) {
+ skb_queue_head(&sk->sk_receive_queue, skb);
+ if (copied == 0)
+ copied = -EFAULT;
+ break;
+ }
+ copied += chunk;
+ size -= chunk;
+
+ /* Mark read part of skb as used */
+ if (!(flags & MSG_PEEK)) {
+ skb_pull(skb, chunk);
+
+ /* put the skb back if we didn't use it up. */
+ if (skb->len) {
+ skb_queue_head(&sk->sk_receive_queue, skb);
+ break;
+ }
+ kfree_skb(skb);
+
+ } else {
+ /*
+ * It is questionable, see note in unix_dgram_recvmsg.
+ */
+ /* put message back and return */
+ skb_queue_head(&sk->sk_receive_queue, skb);
+ break;
+ }
+ } while (size);
+ caif_read_unlock(sk);
+
+out:
+ return copied ? : err;
+}
+
+/*
+ * Copied from sock.c:sock_wait_for_wmem, but change to wait for
+ * CAIF flow-on and sock_writable.
+ */
+static long caif_wait_for_flow_on(struct caifsock *cf_sk,
+ int wait_writeable, long timeo, int *err)
+{
+ struct sock *sk = &cf_sk->sk;
+ DEFINE_WAIT(wait);
+ for (;;) {
+ *err = 0;
+ if (tx_flow_is_on(cf_sk) &&
+ (!wait_writeable || sock_writeable(&cf_sk->sk)))
+ break;
+ *err = -ETIMEDOUT;
+ if (!timeo)
+ break;
+ *err = -ERESTARTSYS;
+ if (signal_pending(current))
+ break;
+ prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
+ *err = -ECONNRESET;
+ if (sk->sk_shutdown & SHUTDOWN_MASK)
+ break;
+ *err = -sk->sk_err;
+ if (sk->sk_err)
+ break;
+ *err = -EPIPE;
+ if (cf_sk->sk.sk_state != CAIF_CONNECTED)
+ break;
+ timeo = schedule_timeout(timeo);
+ }
+ finish_wait(sk_sleep(sk), &wait);
+ return timeo;
+}
+
+/*
+ * Transmit a SKB. The device may temporarily request re-transmission
+ * by returning EAGAIN.
+ */
+static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk,
+ int noblock, long timeo)
+{
+ struct cfpkt *pkt;
+
+ pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
+ memset(skb->cb, 0, sizeof(struct caif_payload_info));
+ cfpkt_set_prio(pkt, cf_sk->sk.sk_priority);
+
+ if (cf_sk->layer.dn == NULL) {
+ kfree_skb(skb);
+ return -EINVAL;
+ }
+
+ return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
+}
+
+/* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */
+static int caif_seqpkt_sendmsg(struct socket *sock, struct msghdr *msg,
+ size_t len)
+{
+ struct sock *sk = sock->sk;
+ struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
+ int buffer_size;
+ int ret = 0;
+ struct sk_buff *skb = NULL;
+ int noblock;
+ long timeo;
+ caif_assert(cf_sk);
+ ret = sock_error(sk);
+ if (ret)
+ goto err;
+
+ ret = -EOPNOTSUPP;
+ if (msg->msg_flags&MSG_OOB)
+ goto err;
+
+ ret = -EOPNOTSUPP;
+ if (msg->msg_namelen)
+ goto err;
+
+ noblock = msg->msg_flags & MSG_DONTWAIT;
+
+ timeo = sock_sndtimeo(sk, noblock);
+ timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
+ 1, timeo, &ret);
+
+ if (ret)
+ goto err;
+ ret = -EPIPE;
+ if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
+ sock_flag(sk, SOCK_DEAD) ||
+ (sk->sk_shutdown & RCV_SHUTDOWN))
+ goto err;
+
+ /* Error if trying to write more than maximum frame size. */
+ ret = -EMSGSIZE;
+ if (len > cf_sk->maxframe && cf_sk->sk.sk_protocol != CAIFPROTO_RFM)
+ goto err;
+
+ buffer_size = len + cf_sk->headroom + cf_sk->tailroom;
+
+ ret = -ENOMEM;
+ skb = sock_alloc_send_skb(sk, buffer_size, noblock, &ret);
+
+ if (!skb || skb_tailroom(skb) < buffer_size)
+ goto err;
+
+ skb_reserve(skb, cf_sk->headroom);
+
+ ret = memcpy_from_msg(skb_put(skb, len), msg, len);
+
+ if (ret)
+ goto err;
+ ret = transmit_skb(skb, cf_sk, noblock, timeo);
+ if (ret < 0)
+ /* skb is already freed */
+ return ret;
+
+ return len;
+err:
+ kfree_skb(skb);
+ return ret;
+}
+
+/*
+ * Copied from unix_stream_sendmsg and adapted to CAIF:
+ * Changed removed permission handling and added waiting for flow on
+ * and other minor adaptations.
+ */
+static int caif_stream_sendmsg(struct socket *sock, struct msghdr *msg,
+ size_t len)
+{
+ struct sock *sk = sock->sk;
+ struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
+ int err, size;
+ struct sk_buff *skb;
+ int sent = 0;
+ long timeo;
+
+ err = -EOPNOTSUPP;
+ if (unlikely(msg->msg_flags&MSG_OOB))
+ goto out_err;
+
+ if (unlikely(msg->msg_namelen))
+ goto out_err;
+
+ timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
+ timeo = caif_wait_for_flow_on(cf_sk, 1, timeo, &err);
+
+ if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
+ goto pipe_err;
+
+ while (sent < len) {
+
+ size = len-sent;
+
+ if (size > cf_sk->maxframe)
+ size = cf_sk->maxframe;
+
+ /* If size is more than half of sndbuf, chop up message */
+ if (size > ((sk->sk_sndbuf >> 1) - 64))
+ size = (sk->sk_sndbuf >> 1) - 64;
+
+ if (size > SKB_MAX_ALLOC)
+ size = SKB_MAX_ALLOC;
+
+ skb = sock_alloc_send_skb(sk,
+ size + cf_sk->headroom +
+ cf_sk->tailroom,
+ msg->msg_flags&MSG_DONTWAIT,
+ &err);
+ if (skb == NULL)
+ goto out_err;
+
+ skb_reserve(skb, cf_sk->headroom);
+ /*
+ * If you pass two values to the sock_alloc_send_skb
+ * it tries to grab the large buffer with GFP_NOFS
+ * (which can fail easily), and if it fails grab the
+ * fallback size buffer which is under a page and will
+ * succeed. [Alan]
+ */
+ size = min_t(int, size, skb_tailroom(skb));
+
+ err = memcpy_from_msg(skb_put(skb, size), msg, size);
+ if (err) {
+ kfree_skb(skb);
+ goto out_err;
+ }
+ err = transmit_skb(skb, cf_sk,
+ msg->msg_flags&MSG_DONTWAIT, timeo);
+ if (err < 0)
+ /* skb is already freed */
+ goto pipe_err;
+
+ sent += size;
+ }
+
+ return sent;
+
+pipe_err:
+ if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))
+ send_sig(SIGPIPE, current, 0);
+ err = -EPIPE;
+out_err:
+ return sent ? : err;
+}
+
+static int setsockopt(struct socket *sock, int lvl, int opt, sockptr_t ov,
+ unsigned int ol)
+{
+ struct sock *sk = sock->sk;
+ struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
+ int linksel;
+
+ if (cf_sk->sk.sk_socket->state != SS_UNCONNECTED)
+ return -ENOPROTOOPT;
+
+ switch (opt) {
+ case CAIFSO_LINK_SELECT:
+ if (ol < sizeof(int))
+ return -EINVAL;
+ if (lvl != SOL_CAIF)
+ goto bad_sol;
+ if (copy_from_sockptr(&linksel, ov, sizeof(int)))
+ return -EINVAL;
+ lock_sock(&(cf_sk->sk));
+ cf_sk->conn_req.link_selector = linksel;
+ release_sock(&cf_sk->sk);
+ return 0;
+
+ case CAIFSO_REQ_PARAM:
+ if (lvl != SOL_CAIF)
+ goto bad_sol;
+ if (cf_sk->sk.sk_protocol != CAIFPROTO_UTIL)
+ return -ENOPROTOOPT;
+ lock_sock(&(cf_sk->sk));
+ if (ol > sizeof(cf_sk->conn_req.param.data) ||
+ copy_from_sockptr(&cf_sk->conn_req.param.data, ov, ol)) {
+ release_sock(&cf_sk->sk);
+ return -EINVAL;
+ }
+ cf_sk->conn_req.param.size = ol;
+ release_sock(&cf_sk->sk);
+ return 0;
+
+ default:
+ return -ENOPROTOOPT;
+ }
+
+ return 0;
+bad_sol:
+ return -ENOPROTOOPT;
+
+}
+
+/*
+ * caif_connect() - Connect a CAIF Socket
+ * Copied and modified af_irda.c:irda_connect().
+ *
+ * Note : by consulting "errno", the user space caller may learn the cause
+ * of the failure. Most of them are visible in the function, others may come
+ * from subroutines called and are listed here :
+ * o -EAFNOSUPPORT: bad socket family or type.
+ * o -ESOCKTNOSUPPORT: bad socket type or protocol
+ * o -EINVAL: bad socket address, or CAIF link type
+ * o -ECONNREFUSED: remote end refused the connection.
+ * o -EINPROGRESS: connect request sent but timed out (or non-blocking)
+ * o -EISCONN: already connected.
+ * o -ETIMEDOUT: Connection timed out (send timeout)
+ * o -ENODEV: No link layer to send request
+ * o -ECONNRESET: Received Shutdown indication or lost link layer
+ * o -ENOMEM: Out of memory
+ *
+ * State Strategy:
+ * o sk_state: holds the CAIF_* protocol state, it's updated by
+ * caif_ctrl_cb.
+ * o sock->state: holds the SS_* socket state and is updated by connect and
+ * disconnect.
+ */
+static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
+ int addr_len, int flags)
+{
+ struct sock *sk = sock->sk;
+ struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
+ long timeo;
+ int err;
+ int ifindex, headroom, tailroom;
+ unsigned int mtu;
+ struct net_device *dev;
+
+ lock_sock(sk);
+
+ err = -EINVAL;
+ if (addr_len < offsetofend(struct sockaddr, sa_family))
+ goto out;
+
+ err = -EAFNOSUPPORT;
+ if (uaddr->sa_family != AF_CAIF)
+ goto out;
+
+ switch (sock->state) {
+ case SS_UNCONNECTED:
+ /* Normal case, a fresh connect */
+ caif_assert(sk->sk_state == CAIF_DISCONNECTED);
+ break;
+ case SS_CONNECTING:
+ switch (sk->sk_state) {
+ case CAIF_CONNECTED:
+ sock->state = SS_CONNECTED;
+ err = -EISCONN;
+ goto out;
+ case CAIF_DISCONNECTED:
+ /* Reconnect allowed */
+ break;
+ case CAIF_CONNECTING:
+ err = -EALREADY;
+ if (flags & O_NONBLOCK)
+ goto out;
+ goto wait_connect;
+ }
+ break;
+ case SS_CONNECTED:
+ caif_assert(sk->sk_state == CAIF_CONNECTED ||
+ sk->sk_state == CAIF_DISCONNECTED);
+ if (sk->sk_shutdown & SHUTDOWN_MASK) {
+ /* Allow re-connect after SHUTDOWN_IND */
+ caif_disconnect_client(sock_net(sk), &cf_sk->layer);
+ caif_free_client(&cf_sk->layer);
+ break;
+ }
+ /* No reconnect on a seqpacket socket */
+ err = -EISCONN;
+ goto out;
+ case SS_DISCONNECTING:
+ case SS_FREE:
+ caif_assert(1); /*Should never happen */
+ break;
+ }
+ sk->sk_state = CAIF_DISCONNECTED;
+ sock->state = SS_UNCONNECTED;
+ sk_stream_kill_queues(&cf_sk->sk);
+
+ err = -EINVAL;
+ if (addr_len != sizeof(struct sockaddr_caif))
+ goto out;
+
+ memcpy(&cf_sk->conn_req.sockaddr, uaddr,
+ sizeof(struct sockaddr_caif));
+
+ /* Move to connecting socket, start sending Connect Requests */
+ sock->state = SS_CONNECTING;
+ sk->sk_state = CAIF_CONNECTING;
+
+ /* Check priority value comming from socket */
+ /* if priority value is out of range it will be ajusted */
+ if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
+ cf_sk->conn_req.priority = CAIF_PRIO_MAX;
+ else if (cf_sk->sk.sk_priority < CAIF_PRIO_MIN)
+ cf_sk->conn_req.priority = CAIF_PRIO_MIN;
+ else
+ cf_sk->conn_req.priority = cf_sk->sk.sk_priority;
+
+ /*ifindex = id of the interface.*/
+ cf_sk->conn_req.ifindex = cf_sk->sk.sk_bound_dev_if;
+
+ cf_sk->layer.receive = caif_sktrecv_cb;
+
+ err = caif_connect_client(sock_net(sk), &cf_sk->conn_req,
+ &cf_sk->layer, &ifindex, &headroom, &tailroom);
+
+ if (err < 0) {
+ cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
+ cf_sk->sk.sk_state = CAIF_DISCONNECTED;
+ goto out;
+ }
+
+ err = -ENODEV;
+ rcu_read_lock();
+ dev = dev_get_by_index_rcu(sock_net(sk), ifindex);
+ if (!dev) {
+ rcu_read_unlock();
+ goto out;
+ }
+ cf_sk->headroom = LL_RESERVED_SPACE_EXTRA(dev, headroom);
+ mtu = dev->mtu;
+ rcu_read_unlock();
+
+ cf_sk->tailroom = tailroom;
+ cf_sk->maxframe = mtu - (headroom + tailroom);
+ if (cf_sk->maxframe < 1) {
+ pr_warn("CAIF Interface MTU too small (%d)\n", dev->mtu);
+ err = -ENODEV;
+ goto out;
+ }
+
+ err = -EINPROGRESS;
+wait_connect:
+
+ if (sk->sk_state != CAIF_CONNECTED && (flags & O_NONBLOCK))
+ goto out;
+
+ timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
+
+ release_sock(sk);
+ err = -ERESTARTSYS;
+ timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
+ sk->sk_state != CAIF_CONNECTING,
+ timeo);
+ lock_sock(sk);
+ if (timeo < 0)
+ goto out; /* -ERESTARTSYS */
+
+ err = -ETIMEDOUT;
+ if (timeo == 0 && sk->sk_state != CAIF_CONNECTED)
+ goto out;
+ if (sk->sk_state != CAIF_CONNECTED) {
+ sock->state = SS_UNCONNECTED;
+ err = sock_error(sk);
+ if (!err)
+ err = -ECONNREFUSED;
+ goto out;
+ }
+ sock->state = SS_CONNECTED;
+ err = 0;
+out:
+ release_sock(sk);
+ return err;
+}
+
+/*
+ * caif_release() - Disconnect a CAIF Socket
+ * Copied and modified af_irda.c:irda_release().
+ */
+static int caif_release(struct socket *sock)
+{
+ struct sock *sk = sock->sk;
+ struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
+
+ if (!sk)
+ return 0;
+
+ set_tx_flow_off(cf_sk);
+
+ /*
+ * Ensure that packets are not queued after this point in time.
+ * caif_queue_rcv_skb checks SOCK_DEAD holding the queue lock,
+ * this ensures no packets when sock is dead.
+ */
+ spin_lock_bh(&sk->sk_receive_queue.lock);
+ sock_set_flag(sk, SOCK_DEAD);
+ spin_unlock_bh(&sk->sk_receive_queue.lock);
+ sock->sk = NULL;
+
+ WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir));
+ debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
+
+ lock_sock(&(cf_sk->sk));
+ sk->sk_state = CAIF_DISCONNECTED;
+ sk->sk_shutdown = SHUTDOWN_MASK;
+
+ caif_disconnect_client(sock_net(sk), &cf_sk->layer);
+ cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
+ wake_up_interruptible_poll(sk_sleep(sk), EPOLLERR|EPOLLHUP);
+
+ sock_orphan(sk);
+ sk_stream_kill_queues(&cf_sk->sk);
+ release_sock(sk);
+ sock_put(sk);
+ return 0;
+}
+
+/* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */
+static __poll_t caif_poll(struct file *file,
+ struct socket *sock, poll_table *wait)
+{
+ struct sock *sk = sock->sk;
+ __poll_t mask;
+ struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
+
+ sock_poll_wait(file, sock, wait);
+ mask = 0;
+
+ /* exceptional events? */
+ if (sk->sk_err)
+ mask |= EPOLLERR;
+ if (sk->sk_shutdown == SHUTDOWN_MASK)
+ mask |= EPOLLHUP;
+ if (sk->sk_shutdown & RCV_SHUTDOWN)
+ mask |= EPOLLRDHUP;
+
+ /* readable? */
+ if (!skb_queue_empty_lockless(&sk->sk_receive_queue) ||
+ (sk->sk_shutdown & RCV_SHUTDOWN))
+ mask |= EPOLLIN | EPOLLRDNORM;
+
+ /*
+ * we set writable also when the other side has shut down the
+ * connection. This prevents stuck sockets.
+ */
+ if (sock_writeable(sk) && tx_flow_is_on(cf_sk))
+ mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
+
+ return mask;
+}
+
+static const struct proto_ops caif_seqpacket_ops = {
+ .family = PF_CAIF,
+ .owner = THIS_MODULE,
+ .release = caif_release,
+ .bind = sock_no_bind,
+ .connect = caif_connect,
+ .socketpair = sock_no_socketpair,
+ .accept = sock_no_accept,
+ .getname = sock_no_getname,
+ .poll = caif_poll,
+ .ioctl = sock_no_ioctl,
+ .listen = sock_no_listen,
+ .shutdown = sock_no_shutdown,
+ .setsockopt = setsockopt,
+ .sendmsg = caif_seqpkt_sendmsg,
+ .recvmsg = caif_seqpkt_recvmsg,
+ .mmap = sock_no_mmap,
+};
+
+static const struct proto_ops caif_stream_ops = {
+ .family = PF_CAIF,
+ .owner = THIS_MODULE,
+ .release = caif_release,
+ .bind = sock_no_bind,
+ .connect = caif_connect,
+ .socketpair = sock_no_socketpair,
+ .accept = sock_no_accept,
+ .getname = sock_no_getname,
+ .poll = caif_poll,
+ .ioctl = sock_no_ioctl,
+ .listen = sock_no_listen,
+ .shutdown = sock_no_shutdown,
+ .setsockopt = setsockopt,
+ .sendmsg = caif_stream_sendmsg,
+ .recvmsg = caif_stream_recvmsg,
+ .mmap = sock_no_mmap,
+};
+
+/* This function is called when a socket is finally destroyed. */
+static void caif_sock_destructor(struct sock *sk)
+{
+ struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
+ caif_assert(!refcount_read(&sk->sk_wmem_alloc));
+ caif_assert(sk_unhashed(sk));
+ caif_assert(!sk->sk_socket);
+ if (!sock_flag(sk, SOCK_DEAD)) {
+ pr_debug("Attempt to release alive CAIF socket: %p\n", sk);
+ return;
+ }
+ sk_stream_kill_queues(&cf_sk->sk);
+ WARN_ON_ONCE(sk->sk_forward_alloc);
+ caif_free_client(&cf_sk->layer);
+}
+
+static int caif_create(struct net *net, struct socket *sock, int protocol,
+ int kern)
+{
+ struct sock *sk = NULL;
+ struct caifsock *cf_sk = NULL;
+ static struct proto prot = {.name = "PF_CAIF",
+ .owner = THIS_MODULE,
+ .obj_size = sizeof(struct caifsock),
+ .useroffset = offsetof(struct caifsock, conn_req.param),
+ .usersize = sizeof_field(struct caifsock, conn_req.param)
+ };
+
+ if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
+ return -EPERM;
+ /*
+ * The sock->type specifies the socket type to use.
+ * The CAIF socket is a packet stream in the sense
+ * that it is packet based. CAIF trusts the reliability
+ * of the link, no resending is implemented.
+ */
+ if (sock->type == SOCK_SEQPACKET)
+ sock->ops = &caif_seqpacket_ops;
+ else if (sock->type == SOCK_STREAM)
+ sock->ops = &caif_stream_ops;
+ else
+ return -ESOCKTNOSUPPORT;
+
+ if (protocol < 0 || protocol >= CAIFPROTO_MAX)
+ return -EPROTONOSUPPORT;
+ /*
+ * Set the socket state to unconnected. The socket state
+ * is really not used at all in the net/core or socket.c but the
+ * initialization makes sure that sock->state is not uninitialized.
+ */
+ sk = sk_alloc(net, PF_CAIF, GFP_KERNEL, &prot, kern);
+ if (!sk)
+ return -ENOMEM;
+
+ cf_sk = container_of(sk, struct caifsock, sk);
+
+ /* Store the protocol */
+ sk->sk_protocol = (unsigned char) protocol;
+
+ /* Initialize default priority for well-known cases */
+ switch (protocol) {
+ case CAIFPROTO_AT:
+ sk->sk_priority = TC_PRIO_CONTROL;
+ break;
+ case CAIFPROTO_RFM:
+ sk->sk_priority = TC_PRIO_INTERACTIVE_BULK;
+ break;
+ default:
+ sk->sk_priority = TC_PRIO_BESTEFFORT;
+ }
+
+ /*
+ * Lock in order to try to stop someone from opening the socket
+ * too early.
+ */
+ lock_sock(&(cf_sk->sk));
+
+ /* Initialize the nozero default sock structure data. */
+ sock_init_data(sock, sk);
+ sk->sk_destruct = caif_sock_destructor;
+
+ mutex_init(&cf_sk->readlock); /* single task reading lock */
+ cf_sk->layer.ctrlcmd = caif_ctrl_cb;
+ cf_sk->sk.sk_socket->state = SS_UNCONNECTED;
+ cf_sk->sk.sk_state = CAIF_DISCONNECTED;
+
+ set_tx_flow_off(cf_sk);
+ set_rx_flow_on(cf_sk);
+
+ /* Set default options on configuration */
+ cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY;
+ cf_sk->conn_req.protocol = protocol;
+ release_sock(&cf_sk->sk);
+ return 0;
+}
+
+
+static const struct net_proto_family caif_family_ops = {
+ .family = PF_CAIF,
+ .create = caif_create,
+ .owner = THIS_MODULE,
+};
+
+static int __init caif_sktinit_module(void)
+{
+ return sock_register(&caif_family_ops);
+}
+
+static void __exit caif_sktexit_module(void)
+{
+ sock_unregister(PF_CAIF);
+}
+module_init(caif_sktinit_module);
+module_exit(caif_sktexit_module);