From dbea17bc836a776fa427415dc4237de9512858bb Mon Sep 17 00:00:00 2001
From: bms <bms@FreeBSD.org>
Date: Tue, 15 Jun 2004 01:08:09 +0000
Subject: [PATCH] Add a paragraph about the importance of byte order when using
 raw sockets with the IP_HDRINCL option. Add a list entry about the errors
 which IP_HDRINCL can return. Bump .Dd.

PR:		docs/30873
Submitted by:	Douglas De Couto
Obtained from:	BSD/OS (byte order), some old libnet stuff I did years ago.
---
 share/man/man4/ip.4 | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/share/man/man4/ip.4 b/share/man/man4/ip.4
index b82e42171742..1377941ecb93 100644
--- a/share/man/man4/ip.4
+++ b/share/man/man4/ip.4
@@ -32,7 +32,7 @@
 .\"     @(#)ip.4	8.2 (Berkeley) 11/30/93
 .\" $FreeBSD$
 .\"
-.Dd March 3, 2001
+.Dd June 14, 2004
 .Dt IP 4
 .Os
 .Sh NAME
@@ -529,6 +529,14 @@ ip->ip_id = 0;  /* 0 means kernel set appropriate value */
 ip->ip_off = offset;
 .Ed
 .Pp
+The ip_len and ip_off fields
+.Em must be provided in host byte order .
+All other fields must be provided in network byte order.
+See
+.Xr byteorder 4
+for more information on network byte order.
+If the ip_id field is set to 0, then the kernel will choose an
+appopriate value.
 If the header source address is set to
 .Dv INADDR_ANY ,
 the kernel will choose an appropriate address.
@@ -568,10 +576,24 @@ The IP option field was improperly formed;
 an option field was shorter than the minimum value
 or longer than the option buffer provided.
 .El
+.Pp
+The following errors may occur when attempting to send
+.Tn IP
+datagrams via a
+.Dq raw socket
+with the
+.Em IP_HDRINCL
+option set:
+.Bl -tag -width Er
+.It Bq Er EINVAL
+The user-supplied ip_len field was not equal to the length of the datagram
+written to the socket.
+.El
 .Sh SEE ALSO
 .Xr getsockopt 2 ,
 .Xr recv 2 ,
 .Xr send 2 ,
+.Xr byteorder 4 ,
 .Xr icmp 4 ,
 .Xr inet 4 ,
 .Xr intro 4