diff --git a/sys/dev/virtual/net/if_vke.c b/sys/dev/virtual/net/if_vke.c
index 498777a5827b..2216a1388b52 100644
--- a/sys/dev/virtual/net/if_vke.c
+++ b/sys/dev/virtual/net/if_vke.c
@@ -31,7 +31,7 @@
  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  * 
- * $DragonFly: src/sys/dev/virtual/net/if_vke.c,v 1.8 2008/05/27 01:10:38 dillon Exp $
+ * $DragonFly: src/sys/dev/virtual/net/if_vke.c,v 1.9 2008/05/27 05:25:33 dillon Exp $
  */
 
 #include <sys/param.h>
@@ -156,11 +156,17 @@ vke_start(struct ifnet *ifp)
 		return;
 
 	while ((m = ifq_dequeue(&ifp->if_snd, NULL)) != NULL) {
+		/*
+		 * Copy the data into a single mbuf and write it out
+		 * non-blocking.
+		 */
 		if (m->m_pkthdr.len <= MCLBYTES) {
 			m_copydata(m, 0, m->m_pkthdr.len, sc->sc_txbuf);
 			BPF_MTAP(ifp, m);
-			write(sc->sc_fd, sc->sc_txbuf, m->m_pkthdr.len);
-			ifp->if_opackets++;
+			if (write(sc->sc_fd, sc->sc_txbuf, m->m_pkthdr.len) < 0)
+				ifp->if_oerrors++;
+			else
+				ifp->if_opackets++;
 		} else {
 			ifp->if_oerrors++;
 		}
diff --git a/sys/kern/kern_resource.c b/sys/kern/kern_resource.c
index 614d7342c19e..2e074294da6a 100644
--- a/sys/kern/kern_resource.c
+++ b/sys/kern/kern_resource.c
@@ -37,7 +37,7 @@
  *
  *	@(#)kern_resource.c	8.5 (Berkeley) 1/21/94
  * $FreeBSD: src/sys/kern/kern_resource.c,v 1.55.2.5 2001/11/03 01:41:08 ps Exp $
- * $DragonFly: src/sys/kern/kern_resource.c,v 1.34 2007/08/20 05:40:40 dillon Exp $
+ * $DragonFly: src/sys/kern/kern_resource.c,v 1.35 2008/05/27 05:25:34 dillon Exp $
  */
 
 #include "opt_compat.h"
@@ -682,10 +682,19 @@ chgsbsize(struct uidinfo *uip, u_long *hiwat, u_long to, rlim_t max)
 
 	crit_enter();
 	new = uip->ui_sbsize + to - *hiwat;
-	/* don't allow them to exceed max, but allow subtraction */
-	if (to > *hiwat && new > max) {
-		crit_exit();
-		return (0);
+
+	/*
+	 * If we are trying to increase the socket buffer size
+	 * Scale down the hi water mark when we exceed the user's
+	 * allowed socket buffer space.
+	 *
+	 * We can't scale down too much or we will blow up atomic packet
+	 * operations.
+	 */
+	if (to > *hiwat && to > MCLBYTES && new > max) {
+		to = to * max / new;
+		if (to < MCLBYTES)
+			to = MCLBYTES;
 	}
 	uip->ui_sbsize = new;
 	*hiwat = to;
diff --git a/sys/kern/uipc_socket.c b/sys/kern/uipc_socket.c
index c908b26788d6..f9b1afe3797e 100644
--- a/sys/kern/uipc_socket.c
+++ b/sys/kern/uipc_socket.c
@@ -65,7 +65,7 @@
  *
  *	@(#)uipc_socket.c	8.3 (Berkeley) 4/15/94
  * $FreeBSD: src/sys/kern/uipc_socket.c,v 1.68.2.24 2003/11/11 17:18:18 silby Exp $
- * $DragonFly: src/sys/kern/uipc_socket.c,v 1.47 2008/01/05 14:02:38 swildner Exp $
+ * $DragonFly: src/sys/kern/uipc_socket.c,v 1.48 2008/05/27 05:25:34 dillon Exp $
  */
 
 #include "opt_inet.h"
@@ -554,12 +554,13 @@ sosend(struct socket *so, struct sockaddr *addr, struct uio *uio,
 			    gotoerr(so->so_proto->pr_flags & PR_CONNREQUIRED ?
 				   ENOTCONN : EDESTADDRREQ);
 		}
+		if ((atomic && resid > so->so_snd.ssb_hiwat) ||
+		    clen > so->so_snd.ssb_hiwat) {
+			gotoerr(EMSGSIZE);
+		}
 		space = ssb_space(&so->so_snd);
 		if (flags & MSG_OOB)
 			space += 1024;
-		if ((atomic && resid > so->so_snd.ssb_hiwat) ||
-		    clen > so->so_snd.ssb_hiwat)
-			gotoerr(EMSGSIZE);
 		if (space < resid + clen && uio &&
 		    (atomic || space < so->so_snd.ssb_lowat || space < clen)) {
 			if (flags & (MSG_FNONBLOCKING|MSG_DONTWAIT))
diff --git a/sys/kern/uipc_socket2.c b/sys/kern/uipc_socket2.c
index 4d96f6354412..0d7faff27533 100644
--- a/sys/kern/uipc_socket2.c
+++ b/sys/kern/uipc_socket2.c
@@ -33,7 +33,7 @@
  *
  *	@(#)uipc_socket2.c	8.1 (Berkeley) 6/10/93
  * $FreeBSD: src/sys/kern/uipc_socket2.c,v 1.55.2.17 2002/08/31 19:04:55 dwmalone Exp $
- * $DragonFly: src/sys/kern/uipc_socket2.c,v 1.30 2008/04/20 13:44:25 swildner Exp $
+ * $DragonFly: src/sys/kern/uipc_socket2.c,v 1.31 2008/05/27 05:25:34 dillon Exp $
  */
 
 #include "opt_param.h"
@@ -423,7 +423,7 @@ ssb_reserve(struct signalsockbuf *ssb, u_long cc, struct socket *so,
 	 * or when called from netgraph (ie, ngd_attach)
 	 */
 	if (cc > sb_max_adj)
-		return (0);
+		cc = sb_max_adj;
 	if (!chgsbsize(so->so_cred->cr_uidinfo, &ssb->ssb_hiwat, cc,
 		       rl ? rl->rlim_cur : RLIM_INFINITY)) {
 		return (0);
diff --git a/sys/kern/uipc_usrreq.c b/sys/kern/uipc_usrreq.c
index c414391ad66a..a851a6b5826b 100644
--- a/sys/kern/uipc_usrreq.c
+++ b/sys/kern/uipc_usrreq.c
@@ -32,7 +32,7 @@
  *
  *	From: @(#)uipc_usrreq.c	8.3 (Berkeley) 1/4/94
  * $FreeBSD: src/sys/kern/uipc_usrreq.c,v 1.54.2.10 2003/03/04 17:28:09 nectar Exp $
- * $DragonFly: src/sys/kern/uipc_usrreq.c,v 1.40 2008/05/27 01:10:39 dillon Exp $
+ * $DragonFly: src/sys/kern/uipc_usrreq.c,v 1.41 2008/05/27 05:25:34 dillon Exp $
  */
 
 #include <sys/param.h>
@@ -71,7 +71,7 @@ static	struct unp_head unp_shead, unp_dhead;
  * Unix communications domain.
  *
  * TODO:
- *	SEQPACKET, RDM
+ *	RDM
  *	rethink name space problems
  *	need a proper out-of-band
  *	lock pushdown
@@ -233,7 +233,6 @@ uipc_rcvd(struct socket *so, int flags)
 {
 	struct unpcb *unp = so->so_pcb;
 	struct socket *so2;
-	u_long newhiwat;
 
 	if (unp == NULL)
 		return EINVAL;
@@ -246,19 +245,18 @@ uipc_rcvd(struct socket *so, int flags)
 	case SOCK_SEQPACKET:
 		if (unp->unp_conn == NULL)
 			break;
-		so2 = unp->unp_conn->unp_socket;
 		/*
-		 * Adjust backpressure on sender
-		 * and wakeup any waiting to write.
+		 * Because we are transfering mbufs directly to the
+		 * peer socket we have to use SSB_STOP on the sender
+		 * to prevent it from building up infinite mbufs.
 		 */
-		so2->so_snd.ssb_mbmax += unp->unp_mbcnt - so->so_rcv.ssb_mbcnt;
-		unp->unp_mbcnt = so->so_rcv.ssb_mbcnt;
-		newhiwat =
-		    so2->so_snd.ssb_hiwat + unp->unp_cc - so->so_rcv.ssb_cc;
-		chgsbsize(so2->so_cred->cr_uidinfo, &so2->so_snd.ssb_hiwat,
-		    newhiwat, RLIM_INFINITY);
-		unp->unp_cc = so->so_rcv.ssb_cc;
-		sowwakeup(so2);
+		so2 = unp->unp_conn->unp_socket;
+		if (so->so_rcv.ssb_cc < so2->so_snd.ssb_hiwat &&
+		    so->so_rcv.ssb_mbcnt < so2->so_snd.ssb_mbmax
+		) {
+			so2->so_snd.ssb_flags &= ~SSB_STOP;
+			sowwakeup(so2);
+		}
 		break;
 
 	default:
@@ -276,7 +274,6 @@ uipc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
 	int error = 0;
 	struct unpcb *unp = so->so_pcb;
 	struct socket *so2;
-	u_long newhiwat;
 
 	if (unp == NULL) {
 		error = EINVAL;
@@ -368,14 +365,17 @@ uipc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
 			sbappend(&so2->so_rcv.sb, m);
 			m = NULL;
 		}
-		so->so_snd.ssb_mbmax -=
-			so2->so_rcv.ssb_mbcnt - unp->unp_conn->unp_mbcnt;
-		unp->unp_conn->unp_mbcnt = so2->so_rcv.ssb_mbcnt;
-		newhiwat = so->so_snd.ssb_hiwat -
-		    (so2->so_rcv.ssb_cc - unp->unp_conn->unp_cc);
-		chgsbsize(so->so_cred->cr_uidinfo, &so->so_snd.ssb_hiwat,
-		    newhiwat, RLIM_INFINITY);
-		unp->unp_conn->unp_cc = so2->so_rcv.ssb_cc;
+
+		/*
+		 * Because we are transfering mbufs directly to the
+		 * peer socket we have to use SSB_STOP on the sender
+		 * to prevent it from building up infinite mbufs.
+		 */
+		if (so2->so_rcv.ssb_cc >= so->so_snd.ssb_hiwat ||
+		    so2->so_rcv.ssb_mbcnt >= so->so_snd.ssb_mbmax
+		) {
+			so->so_snd.ssb_flags |= SSB_STOP;
+		}
 		sorwakeup(so2);
 		break;
 
@@ -406,16 +406,10 @@ static int
 uipc_sense(struct socket *so, struct stat *sb)
 {
 	struct unpcb *unp = so->so_pcb;
-	struct socket *so2;
 
 	if (unp == NULL)
 		return EINVAL;
 	sb->st_blksize = so->so_snd.ssb_hiwat;
-	if ((so->so_type == SOCK_STREAM || so->so_type == SOCK_SEQPACKET) &&
-	    unp->unp_conn != NULL) {
-		so2 = unp->unp_conn->unp_socket;
-		sb->st_blksize += so2->so_rcv.ssb_cc;
-	}
 	sb->st_dev = NOUDEV;
 	if (unp->unp_ino == 0)		/* make up a non-zero inode number */
 		unp->unp_ino = (++unp_ino == 0) ? ++unp_ino : unp_ino;
diff --git a/sys/platform/vkernel/platform/init.c b/sys/platform/vkernel/platform/init.c
index 45ba458473b4..52da57d0f0e9 100644
--- a/sys/platform/vkernel/platform/init.c
+++ b/sys/platform/vkernel/platform/init.c
@@ -31,7 +31,7 @@
  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  * 
- * $DragonFly: src/sys/platform/vkernel/platform/init.c,v 1.54 2008/05/27 01:10:45 dillon Exp $
+ * $DragonFly: src/sys/platform/vkernel/platform/init.c,v 1.55 2008/05/27 05:25:35 dillon Exp $
  */
 
 #include <sys/types.h>
@@ -973,6 +973,8 @@ unix_connect(const char *path)
 	struct sockaddr_un sunx;
 	int len;
 	int net_fd;
+	int sndbuf = 262144;
+	struct stat st;
 
 	snprintf(sunx.sun_path, sizeof(sunx.sun_path), "%s", path);
 	len = offsetof(struct sockaddr_un, sun_path[strlen(sunx.sun_path)]);
@@ -987,6 +989,9 @@ unix_connect(const char *path)
 		close(net_fd);
 		return(-1);
 	}
+	setsockopt(net_fd, SOL_SOCKET, SO_SNDBUF, &sndbuf, sizeof(sndbuf));
+	if (fstat(net_fd, &st) == 0)
+		printf("Network socket buffer: %d bytes\n", st.st_blksize);
 	fcntl(net_fd, F_SETFL, O_NONBLOCK);
 	return(net_fd);
 }
diff --git a/sys/sys/socketvar.h b/sys/sys/socketvar.h
index e8037393eacd..ea5cebed47d4 100644
--- a/sys/sys/socketvar.h
+++ b/sys/sys/socketvar.h
@@ -32,7 +32,7 @@
  *
  *	@(#)socketvar.h	8.3 (Berkeley) 2/19/95
  * $FreeBSD: src/sys/sys/socketvar.h,v 1.46.2.10 2003/08/24 08:24:39 hsu Exp $
- * $DragonFly: src/sys/sys/socketvar.h,v 1.30 2007/11/07 18:24:04 dillon Exp $
+ * $DragonFly: src/sys/sys/socketvar.h,v 1.31 2008/05/27 05:25:36 dillon Exp $
  */
 
 #ifndef _SYS_SOCKETVAR_H_
@@ -83,6 +83,7 @@ struct signalsockbuf {
 #define SSB_AIO		0x80		/* AIO operations queued */
 #define SSB_KNOTE	0x100		/* kernel note attached */
 #define SSB_MEVENT	0x200		/* need message event notification */
+#define SSB_STOP	0x400		/* backpressure indicator */
 
 /*
  * Per-socket kernel structure.  Contains universal send and receive queues,
@@ -220,11 +221,24 @@ struct	xsocket {
  * How much space is there in a socket buffer (so->so_snd or so->so_rcv)?
  * This is problematical if the fields are unsigned, as the space might
  * still be negative (cc > hiwat or mbcnt > mbmax).  Should detect
- * overflow and return 0.  Should use "lmin" but it doesn't exist now.
+ * overflow and return 0.
+ *
+ * SSB_STOP ignores cc/hiwat and returns 0.  This is used by unix domain
+ * stream sockets to signal backpressure.
  */
-#define ssb_space(ssb) 							\
-	((long)imin((int)((ssb)->ssb_hiwat - (ssb)->ssb_cc),		\
-		    (int)((ssb)->ssb_mbmax - (ssb)->ssb_mbcnt)))
+static __inline
+long
+ssb_space(struct signalsockbuf *ssb)
+{
+	long bleft;
+	long mleft;
+
+	if (ssb->ssb_flags & SSB_STOP)
+		return(0);
+	bleft = ssb->ssb_hiwat - ssb->ssb_cc;
+	mleft = ssb->ssb_mbmax - ssb->ssb_mbcnt;
+	return((bleft < mleft) ? bleft : mleft);
+}
 
 #define ssb_append(ssb, m)						\
 	sbappend(&(ssb)->sb, m)
diff --git a/sys/sys/unpcb.h b/sys/sys/unpcb.h
index 2c5cb3f46036..bb39f0e0a41b 100644
--- a/sys/sys/unpcb.h
+++ b/sys/sys/unpcb.h
@@ -32,7 +32,7 @@
  *
  *	@(#)unpcb.h	8.1 (Berkeley) 6/2/93
  * $FreeBSD: src/sys/sys/unpcb.h,v 1.9.2.1 2002/03/09 05:22:23 dd Exp $
- * $DragonFly: src/sys/sys/unpcb.h,v 1.4 2005/04/20 19:38:22 hsu Exp $
+ * $DragonFly: src/sys/sys/unpcb.h,v 1.5 2008/05/27 05:25:36 dillon Exp $
  */
 
 #ifndef _SYS_UNPCB_H_
@@ -79,8 +79,8 @@ struct	unpcb {
 	struct	unp_head unp_refs;	/* referencing socket linked list */
 	LIST_ENTRY(unpcb) unp_reflink;	/* link in unp_refs list */
 	struct	sockaddr_un *unp_addr;	/* bound address of socket */
-	int	unp_cc;			/* copy of rcv.sb_cc */
-	int	unp_mbcnt;		/* copy of rcv.sb_mbcnt */
+	int	unused01;
+	int	unused02;
 	unp_gen_t unp_gencnt;		/* generation count of this instance */
 	int	unp_flags;		/* flags */
 	struct	xucred unp_peercred;	/* peer credentials, if applicable */