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authorJared Yanovich <jaredy@cvs.openbsd.org>2004-12-18 20:33:12 +0000
committerJared Yanovich <jaredy@cvs.openbsd.org>2004-12-18 20:33:12 +0000
commit220f5907de5bdc773b687af762aa5d835e26025c (patch)
tree8eb9789f73842e540db33882755609d89acfff4f
parent3c38fda6f253ff1df8af96f21cf64cf8fd4535bf (diff)
cleanup and indent examples. ok jmc
-rw-r--r--share/man/man4/ip.481
1 files changed, 48 insertions, 33 deletions
diff --git a/share/man/man4/ip.4 b/share/man/man4/ip.4
index 9a5ad54bad1..72a689f2ead 100644
--- a/share/man/man4/ip.4
+++ b/share/man/man4/ip.4
@@ -1,4 +1,4 @@
-.\" $OpenBSD: ip.4,v 1.22 2003/08/08 09:51:53 jmc Exp $
+.\" $OpenBSD: ip.4,v 1.23 2004/12/18 20:33:11 jaredy Exp $
.\" $NetBSD: ip.4,v 1.3 1994/11/30 16:22:19 jtc Exp $
.\"
.\" Copyright (c) 1983, 1991, 1993
@@ -84,7 +84,7 @@ The first-hop gateway address will be extracted from the option list
and the size adjusted accordingly before use.
To disable previously specified options,
use a zero-length buffer:
-.Bd -literal
+.Bd -literal -offset indent
setsockopt(s, IPPROTO_IP, IP_OPTIONS, NULL, 0);
.Ed
.Pp
@@ -100,7 +100,7 @@ and
.Dv SOCK_DGRAM
sockets.
For example,
-.Bd -literal
+.Bd -literal -offset indent
int tos = IPTOS_LOWDELAY; /* see <netinet/ip.h> */
setsockopt(s, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
@@ -120,27 +120,36 @@ call will return the destination
address for a
.Tn UDP
datagram.
-The msg_control field in the msghdr structure points to a buffer
-that contains a cmsghdr structure followed by the
+The
+.Va msg_control
+field in the
+.Vt msghdr
+structure points to a buffer that contains a
+.Vt cmsghdr
+structure followed by the
.Tn IP
address.
-The cmsghdr fields have the following values:
-.Bd -literal
+The
+.Vt cmsghdr
+fields have the following values:
+.Bd -literal -offset indent
cmsg_len = CMSG_LEN(sizeof(struct in_addr))
cmsg_level = IPPROTO_IP
cmsg_type = IP_RECVDSTADDR
.Ed
.Pp
-The IP_PORTRANGE
+The
+.Dv IP_PORTRANGE
option causes the default allocation policy for when the kernel is asked
to choose a free port number.
Three choices are available:
-.Bl -tag -width IP_PORTRANGE_DEFAULT
-.It IP_PORTRANGE_DEFAULT
+.Pp
+.Bl -tag -width IP_PORTRANGE_DEFAULT -compact -offset indent
+.It Dv IP_PORTRANGE_DEFAULT
The regular range of non-reserved ports.
-.It IP_PORTRANGE_HIGH
+.It Dv IP_PORTRANGE_HIGH
A high range, for fun.
-.It IP_PORTRANGE_LOW
+.It Dv IP_PORTRANGE_LOW
Reserved ports; between 600 and 1023.
.El
.Ss "Multicast Options"
@@ -159,11 +168,11 @@ The
option changes the time-to-live (TTL)
for outgoing multicast datagrams
in order to control the scope of the multicasts:
-.Bd -literal
+.Bd -literal -offset indent
u_char ttl; /* range: 0 to 255, default = 1 */
setsockopt(s, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl));
.Ed
-.sp
+.Pp
Datagrams with a TTL of 1 are not forwarded beyond the local network.
Multicast datagrams with a TTL of 0 will not be transmitted on any network,
but may be delivered locally if the sending host belongs to the destination
@@ -178,12 +187,14 @@ The
.Dv IP_MULTICAST_IF
option overrides the default for
subsequent transmissions from a given socket:
-.Bd -literal
+.Bd -literal -offset indent
struct in_addr addr;
setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF, &addr, sizeof(addr));
.Ed
-.sp
-where "addr" is the local
+.Pp
+where
+.Va addr
+is the local
.Tn IP
address of the desired interface or
.Dv INADDR_ANY
@@ -193,7 +204,7 @@ be obtained via the
.Dv SIOCGIFCONF
and
.Dv SIOCGIFFLAGS
-ioctls.
+.Xr ioctl 2 Ns 's .
Normal applications should not need to use this option.
.Pp
If a multicast datagram is sent to a group to which the sending host itself
@@ -203,11 +214,11 @@ The
.Dv IP_MULTICAST_LOOP
option gives the sender explicit control
over whether or not subsequent datagrams are looped back:
-.Bd -literal
+.Bd -literal -offset indent
u_char loop; /* 0 = disable, 1 = enable (default) */
setsockopt(s, IPPROTO_IP, IP_MULTICAST_LOOP, &loop, sizeof(loop));
.Ed
-.sp
+.Pp
This option
improves performance for applications that may have no more than one
instance on a single host (such as a router daemon), by eliminating
@@ -227,22 +238,22 @@ datagrams sent to the group.
To join a multicast group, use the
.Dv IP_ADD_MEMBERSHIP
option:
-.Bd -literal
+.Bd -literal -offset indent
struct ip_mreq mreq;
setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq));
.Ed
-.sp
+.Pp
where
.Fa mreq
is the following structure:
-.Bd -literal
+.Bd -literal -offset indent
struct ip_mreq {
struct in_addr imr_multiaddr; /* multicast group to join */
struct in_addr imr_interface; /* interface to join on */
}
.Ed
-.sp
-.Dv imr_interface
+.Pp
+.Va imr_interface
should
be
.Dv INADDR_ANY
@@ -260,11 +271,11 @@ Up to
single socket.
.Pp
To drop a membership, use:
-.Bd -literal
+.Bd -literal -offset indent
struct ip_mreq mreq;
setsockopt(s, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreq, sizeof(mreq));
.Ed
-.sp
+.Pp
where
.Fa mreq
contains the same values as used to add the membership.
@@ -320,29 +331,32 @@ indicates the complete IP header is included with the data
and may be used only with the
.Dv SOCK_RAW
type.
-.Bd -literal
+.Bd -literal -offset indent
#include <netinet/ip.h>
int hincl = 1; /* 1 = on, 0 = off */
setsockopt(s, IPPROTO_IP, IP_HDRINCL, &hincl, sizeof(hincl));
.Ed
-.sp
+.Pp
Unlike previous
-.Tn BSD
+.Bx
releases, the program must set all
the fields of the IP header, including the following:
-.Bd -literal
+.Bd -literal -offset indent
ip->ip_v = IPVERSION;
ip->ip_hl = hlen >> 2;
ip->ip_id = 0; /* 0 means kernel set appropriate value */
ip->ip_off = htons(offset);
ip->ip_len = htons(len);
.Ed
-.sp .5
.Pp
Additionally note that starting with
.Ox 2.1 ,
-the ip_off and ip_len fields are in network byte order.
+the
+.Va ip_off
+and
+.Va ip_len
+fields are in network byte order.
If the header source address is set to
.Dv INADDR_ANY ,
the kernel will choose an appropriate address.
@@ -384,6 +398,7 @@ or longer than the option buffer provided.
.El
.Sh SEE ALSO
.Xr getsockopt 2 ,
+.Xr ioctl 2 ,
.Xr recv 2 ,
.Xr send 2 ,
.Xr icmp 4 ,