[LLC]: fix llc_ui_recvmsg, making it behave like tcp_recvmsg

In fact it is an exact copy of the parts that makes sense to LLC :-)

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

1 files changed, 147 insertions, 33 deletions

diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c
index 7aa51eb79b13..59d02cbbeb9e 100644
--- a/net/llc/af_llc.c
+++ b/net/llc/af_llc.c
@@ -648,53 +648,167 @@ out:
  *      llc_ui_recvmsg - copy received data to the socket user.
  *      @sock: Socket to copy data from.
  *      @msg: Various user space related information.
- *      @size: Size of user buffer.
+ *      @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 kiocb *iocb, struct socket *sock,
-                          struct msghdr *msg, size_t size, int flags)
+                          struct msghdr *msg, size_t len, int flags)
 {
-        struct sock *sk = sock->sk;
         struct sockaddr_llc *uaddr = (struct sockaddr_llc *)msg->msg_name;
-        struct sk_buff *skb;
+        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;
-        int rc = -ENOMEM;
-        int noblock = flags & MSG_DONTWAIT;
+        u32 peek_seq = 0;
+        u32 *seq;
+        unsigned long used;
+        int target;     /* Read at least this many bytes */
+        long timeo;
 
-        dprintk("%s: receiving in %02X from %02X\n", __FUNCTION__,
-                llc_sk(sk)->laddr.lsap, llc_sk(sk)->daddr.lsap);
         lock_sock(sk);
-        if (skb_queue_empty(&sk->sk_receive_queue)) {
-                rc = llc_wait_data(sk, sock_rcvtimeo(sk, noblock));
-                if (rc)
-                        goto out;
-        }
-        skb = skb_dequeue(&sk->sk_receive_queue);
-        if (!skb) /* shutdown */
+        copied = -ENOTCONN;
+        if (sk->sk_state == TCP_LISTEN)
                 goto out;
-        copied = skb->len;
-        if (copied > size)
-                copied = size;
-        rc = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
-        if (rc)
-                goto dgram_free;
-        if (skb->len > copied) {
-                skb_pull(skb, copied);
-                skb_queue_head(&sk->sk_receive_queue, skb);
-        }
-        if (uaddr)
-                memcpy(uaddr, llc_ui_skb_cb(skb), sizeof(*uaddr));
-        msg->msg_namelen = sizeof(*uaddr);
-        if (!skb->next) {
-dgram_free:
-                kfree_skb(skb);
-        }
+
+        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_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);
+
+                if ((flags & MSG_PEEK) && peek_seq != llc->copied_seq) {
+                        if (net_ratelimit())
+                                printk(KERN_DEBUG "LLC(%s:%d): Application "
+                                                  "bug, race in MSG_PEEK.\n",
+                                       current->comm, current->pid);
+                        peek_seq = llc->copied_seq;
+                }
+                continue;
+        found_ok_skb:
+                /* 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_iovec(skb, offset,
+                                                         msg->msg_iov, used);
+                        if (rc) {
+                                /* Exception. Bailout! */
+                                if (!copied)
+                                        copied = -EFAULT;
+                                break;
+                        }
+                }
+
+                *seq += used;
+                copied += used;
+                len -= used;
+
+                if (used + offset < skb->len)
+                        continue;
+
+                if (!(flags & MSG_PEEK)) {
+                        sk_eat_skb(sk, skb);
+                        *seq = 0;
+                }
+        } while (len > 0);
+
+        /* 
+         * According to UNIX98, msg_name/msg_namelen are ignored
+         * on connected socket. -ANK
+         * But... af_llc still doesn't have separate sets of methods for
+         * SOCK_DGRAM and SOCK_STREAM :-( So we have to do this test, will
+         * eventually fix this tho :-) -acme
+         */
+        if (sk->sk_type == SOCK_DGRAM)
+                goto copy_uaddr;
 out:
         release_sock(sk);
-        return rc ? : copied;
+        return copied;
+copy_uaddr:
+        if (uaddr != NULL && skb != NULL) {
+                memcpy(uaddr, llc_ui_skb_cb(skb), sizeof(*uaddr));
+                msg->msg_namelen = sizeof(*uaddr);
+        }
+        goto out;
 }
 
 /**