tcp: utilize new solisten_clone() and solisten_enqueue()

This streamlines cloning of a socket from a listener.  Now we do not
drop the inpcb lock during creation of a new socket, do not do useless
state transitions, and put a fully initialized socket+inpcb+tcpcb into
the listen queue.

Before this change, first we would allocate the socket and inpcb+tcpcb via
tcp_usr_attach() as TCPS_CLOSED, link them into global list of pcbs, unlock
pcb and put this onto incomplete queue (see 6f3caa6d815).  Then, after
sonewconn() we would lock it again, transition into TCPS_SYN_RECEIVED,
insert into inpcb hash, finalize initialization of tcpcb.  And then, in
call into tcp_do_segment() and upon transition to TCPS_ESTABLISHED call
soisconnected().  This call would lock the listening socket once again
with a LOR protection sequence and then we would relocate the socket onto
the complete queue and only now it is ready for accept(2).

Reviewed by:		rrs, tuexen
Differential revision:	https://reviews.freebsd.org/D36064

1 files changed, 1 insertions, 0 deletions

diff --git a/sys/sys/socketvar.h b/sys/sys/socketvar.h
index ed797c6d6239..678642eeff6d 100644
--- a/sys/sys/socketvar.h
+++ b/sys/sys/socketvar.h
@@ -498,6 +498,7 @@ int	soreceive_generic(struct socket *so, struct sockaddr **paddr,
 	    struct uio *uio, struct mbuf **mp0, struct mbuf **controlp,
 	    int *flagsp);
 void	sorele_locked(struct socket *so);
+void	sodealloc(struct socket *);
 int	soreserve(struct socket *so, u_long sndcc, u_long rcvcc);
 void	sorflush(struct socket *so);
 int	sosend(struct socket *so, struct sockaddr *addr, struct uio *uio,