[PATCH v2 net-next 06/13] tcp: Add tcp_inq to get available receive bytes on socket

[Tom Herbert]

Create a common kernel function to get the number of bytes available
on a TCP socket. This is based on code in INQ getsockopt and we now call
the function for that getsockopt.

Signed-off-by: Tom Herbert <t...@herbertland.com>
---
 include/net/tcp.h | 24 ++++++++++++++++++++++++
 net/ipv4/tcp.c    | 15 +--------------
 2 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/include/net/tcp.h b/include/net/tcp.h
index e90db85..0302636 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1816,4 +1816,28 @@ static inline void skb_set_tcp_pure_ack(struct sk_buff 
*skb)
        skb->truesize = 2;
 }
 
+static inline int tcp_inq(struct sock *sk)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+       int answ;
+
+       if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) {
+               answ = 0;
+       } else if (sock_flag(sk, SOCK_URGINLINE) ||
+                  !tp->urg_data ||
+                  before(tp->urg_seq, tp->copied_seq) ||
+                  !before(tp->urg_seq, tp->rcv_nxt)) {
+
+               answ = tp->rcv_nxt - tp->copied_seq;
+
+               /* Subtract 1, if FIN was received */
+               if (answ && sock_flag(sk, SOCK_DONE))
+                       answ--;
+       } else {
+               answ = tp->urg_seq - tp->copied_seq;
+       }
+
+       return answ;
+}
+
 #endif /* _TCP_H */
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index f9faadb..a265f00 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -556,20 +556,7 @@ int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
                        return -EINVAL;
 
                slow = lock_sock_fast(sk);
-               if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
-                       answ = 0;
-               else if (sock_flag(sk, SOCK_URGINLINE) ||
-                        !tp->urg_data ||
-                        before(tp->urg_seq, tp->copied_seq) ||
-                        !before(tp->urg_seq, tp->rcv_nxt)) {
-
-                       answ = tp->rcv_nxt - tp->copied_seq;
-
-                       /* Subtract 1, if FIN was received */
-                       if (answ && sock_flag(sk, SOCK_DONE))
-                               answ--;
-               } else
-                       answ = tp->urg_seq - tp->copied_seq;
+               answ = tcp_inq(sk);
                unlock_sock_fast(sk, slow);
                break;
        case SIOCATMARK:
-- 
2.6.5