From a52b6c9ce3aa7dd40c5d127ac564eff86c4b0aa9 Mon Sep 17 00:00:00 2001
From: emax <emax@FreeBSD.org>
Date: Wed, 4 May 2005 18:55:03 +0000
Subject: Change m_uiotombuf so it will accept offset at which data should be
 copied to the mbuf. Offset cannot exceed MHLEN bytes. This is currently used
 to fix Ethernet header alignment problem on alpha and sparc64. Also change
 all users of m_uiotombuf to pass proper offset.

Reviewed by:	jmg, sam
Tested by:	Sten Spans "sten AT blinkenlights DOT nl"
MFC after:	1 week
---
 sys/kern/uipc_mbuf.c     | 7 +++++--
 sys/kern/uipc_syscalls.c | 2 +-
 sys/net/if_tap.c         | 2 +-
 sys/net/if_tun.c         | 2 +-
 sys/netgraph/ng_device.c | 2 +-
 sys/sys/mbuf.h           | 2 +-
 6 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/sys/kern/uipc_mbuf.c b/sys/kern/uipc_mbuf.c
index f5ba9ab..ce00553 100644
--- a/sys/kern/uipc_mbuf.c
+++ b/sys/kern/uipc_mbuf.c
@@ -1333,7 +1333,7 @@ nospace:
 #endif
 
 struct mbuf *
-m_uiotombuf(struct uio *uio, int how, int len)
+m_uiotombuf(struct uio *uio, int how, int len, int align)
 {
 	struct mbuf *m_new = NULL, *m_final = NULL;
 	int progress = 0, error = 0, length, total;
@@ -1342,12 +1342,15 @@ m_uiotombuf(struct uio *uio, int how, int len)
 		total = min(uio->uio_resid, len);
 	else
 		total = uio->uio_resid;
-	if (total > MHLEN)
+	if (align >= MHLEN)
+		goto nospace;
+	if (total + align > MHLEN)
 		m_final = m_getcl(how, MT_DATA, M_PKTHDR);
 	else
 		m_final = m_gethdr(how, MT_DATA);
 	if (m_final == NULL)
 		goto nospace;
+	m_final->m_data += align;
 	m_new = m_final;
 	while (progress < total) {
 		length = total - progress;
diff --git a/sys/kern/uipc_syscalls.c b/sys/kern/uipc_syscalls.c
index f4a4b16..2f59d87 100644
--- a/sys/kern/uipc_syscalls.c
+++ b/sys/kern/uipc_syscalls.c
@@ -1796,7 +1796,7 @@ do_sendfile(struct thread *td, struct sendfile_args *uap, int compat)
 			hdr_uio->uio_td = td;
 			hdr_uio->uio_rw = UIO_WRITE;
 			if (hdr_uio->uio_resid > 0) {
-				m_header = m_uiotombuf(hdr_uio, M_DONTWAIT, 0);
+				m_header = m_uiotombuf(hdr_uio, M_DONTWAIT, 0, 0);
 				if (m_header == NULL)
 					goto done;
 				headersize = m_header->m_pkthdr.len;
diff --git a/sys/net/if_tap.c b/sys/net/if_tap.c
index cc07baf..2f7474b 100644
--- a/sys/net/if_tap.c
+++ b/sys/net/if_tap.c
@@ -827,7 +827,7 @@ tapwrite(dev, uio, flag)
 		return (EIO);
 	}
 
-	if ((m = m_uiotombuf(uio, M_DONTWAIT, 0)) == NULL) {
+	if ((m = m_uiotombuf(uio, M_DONTWAIT, 0, ETHER_ALIGN)) == NULL) {
 		ifp->if_ierrors ++;
 		return (error);
 	}
diff --git a/sys/net/if_tun.c b/sys/net/if_tun.c
index 6fe7b10..cd209cb 100644
--- a/sys/net/if_tun.c
+++ b/sys/net/if_tun.c
@@ -761,7 +761,7 @@ tunwrite(struct cdev *dev, struct uio *uio, int flag)
 		return (EIO);
 	}
 
-	if ((m = m_uiotombuf(uio, M_DONTWAIT, 0)) == NULL) {
+	if ((m = m_uiotombuf(uio, M_DONTWAIT, 0, 0)) == NULL) {
 		ifp->if_ierrors++;
 		return (error);
 	}
diff --git a/sys/netgraph/ng_device.c b/sys/netgraph/ng_device.c
index df6ee4c..9439a57 100644
--- a/sys/netgraph/ng_device.c
+++ b/sys/netgraph/ng_device.c
@@ -466,7 +466,7 @@ ngdwrite(struct cdev *dev, struct uio *uio, int flag)
 	if (uio->uio_resid < 0 || uio->uio_resid > IP_MAXPACKET)
 		return (EIO);
 
-	if ((m = m_uiotombuf(uio, M_DONTWAIT, 0)) == NULL)
+	if ((m = m_uiotombuf(uio, M_DONTWAIT, 0, 0)) == NULL)
 		return (ENOBUFS);
 
 	NG_SEND_DATA_ONLY(error, priv->hook, m);
diff --git a/sys/sys/mbuf.h b/sys/sys/mbuf.h
index a3d2a61..c514e0f 100644
--- a/sys/sys/mbuf.h
+++ b/sys/sys/mbuf.h
@@ -582,7 +582,7 @@ void		 m_print(const struct mbuf *, int);
 struct	mbuf	*m_pulldown(struct mbuf *, int, int, int *);
 struct	mbuf	*m_pullup(struct mbuf *, int);
 struct	mbuf	*m_split(struct mbuf *, int, int);
-struct	mbuf	*m_uiotombuf(struct uio *, int, int);
+struct	mbuf	*m_uiotombuf(struct uio *, int, int, int);
 
 /*-
  * Network packets may have annotations attached by affixing a list
-- 
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