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Clarify that port number is 16 bit; reformat long lines

This commit is contained in:
Michael Kerrisk 2005-07-20 07:43:05 +00:00
parent d355f1edc4
commit 3dbef8d0ef
2 changed files with 43 additions and 23 deletions
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@ -8,6 +8,7 @@ Contributors
The following people contributed notes, ideas, or patches that have The following people contributed notes, ideas, or patches that have
been incorporated in changes in this release: been incorporated in changes in this release:
Andrew Pimlott <andrew@pimlott.net>
###Andries Brouwer <Andries.Brouwer@cwi.nl> ###Andries Brouwer <Andries.Brouwer@cwi.nl>
Mike Frysinger <vapier@gentoo.org> Mike Frysinger <vapier@gentoo.org>
@ -26,3 +27,8 @@ Changes to individual pages
stat.2 stat.2
Mike Frysinger Mike Frysinger
Improve st_blocks description. Improve st_blocks description.
ip.7
mtk / Andrew Pimlott
Add a couple of words to make it clear that port is a 16-bit number.
Reformat long source lines (no text changed).

60
man7/ip.7
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@ -28,8 +28,8 @@ Linux implements the Internet Protocol, version 4,
described in RFC\ 791 and RFC\ 1122. described in RFC\ 791 and RFC\ 1122.
.B ip .B ip
contains a level 2 contains a level 2
multicasting implementation conforming to RFC\ 1112. It also contains an IP multicasting implementation conforming to RFC\ 1112.
router including a packet filter. It also contains an IP router including a packet filter.
.\" XXX: has someone verified that 2.1 is really 1812 compliant? .\" XXX: has someone verified that 2.1 is really 1812 compliant?
.PP .PP
The programmer's interface is BSD sockets compatible. The programmer's interface is BSD sockets compatible.
@ -90,7 +90,8 @@ are called on an unbound socket, it is automatically bound to a
random free port with the local address set to random free port with the local address set to
.BR INADDR_ANY . .BR INADDR_ANY .
A TCP local socket address that has been bound is unavailable for some time after closing, A TCP local socket address that has been bound is unavailable for
some time after closing,
unless the unless the
.B SO_REUSEADDR .B SO_REUSEADDR
flag has been set. Care should be taken when using this flag as it flag has been set. Care should be taken when using this flag as it
@ -98,7 +99,8 @@ makes TCP less reliable.
.SH "ADDRESS FORMAT" .SH "ADDRESS FORMAT"
An IP socket address is defined as a combination of an IP interface address An IP socket address is defined as a combination of an IP interface address
and a port number. The basic IP protocol does not supply port numbers, they and a 16-bit port number.
The basic IP protocol does not supply port numbers, they
are implemented by higher level protocols like are implemented by higher level protocols like
.BR udp (7) .BR udp (7)
and and
@ -132,7 +134,8 @@ This is required; in Linux 2.2 most networking functions return
.B EINVAL .B EINVAL
when this setting is missing. when this setting is missing.
.I sin_port .I sin_port
contains the port in network byte order. The port numbers below 1024 are called contains the port in network byte order.
The port numbers below 1024 are called
.IR "reserved ports" . .IR "reserved ports" .
Only processes with effective user ID 0 or the Only processes with effective user ID 0 or the
.B CAP_NET_BIND_SERVICE .B CAP_NET_BIND_SERVICE
@ -159,7 +162,8 @@ should be only accessed using the
library functions or directly with the name resolver (see library functions or directly with the name resolver (see
.BR gethostbyname (3)). .BR gethostbyname (3)).
IPv4 addresses are divided into unicast, broadcast IPv4 addresses are divided into unicast, broadcast
and multicast addresses. Unicast addresses specify a single interface of a host, and multicast addresses.
Unicast addresses specify a single interface of a host,
broadcast addresses specify all hosts on a network and multicast addresses broadcast addresses specify all hosts on a network and multicast addresses
address all hosts in a multicast group. Datagrams to broadcast addresses address all hosts in a multicast group. Datagrams to broadcast addresses
can be only sent or received when the can be only sent or received when the
@ -201,7 +205,8 @@ A boolean integer flag is zero when it is false, otherwise true.
.TP .TP
.B IP_OPTIONS .B IP_OPTIONS
Sets or get the IP options to be sent with every packet from this Sets or get the IP options to be sent with every packet from this
socket. The arguments are a pointer to a memory buffer containing the options socket.
The arguments are a pointer to a memory buffer containing the options
and the option length. and the option length.
The The
.BR setsockopt (2) .BR setsockopt (2)
@ -295,7 +300,8 @@ sockets.
.B IP_RECVOPTS .B IP_RECVOPTS
Pass all incoming IP options to the user in a Pass all incoming IP options to the user in a
.I IP_OPTIONS .I IP_OPTIONS
control message. The routing header and other options are already filled in control message.
The routing header and other options are already filled in
for the local host. Not supported for for the local host. Not supported for
.I SOCK_STREAM .I SOCK_STREAM
sockets. sockets.
@ -309,8 +315,9 @@ options not filled in for this hop.
.TP .TP
.B IP_TOS .B IP_TOS
Set or receive the Type-Of-Service (TOS) field that is sent with every IP packet Set or receive the Type-Of-Service (TOS) field that is sent
originating from this socket. It is used to prioritize packets on the network. with every IP packet originating from this socket.
It is used to prioritize packets on the network.
TOS is a byte. There are some standard TOS flags defined: TOS is a byte. There are some standard TOS flags defined:
.B IPTOS_LOWDELAY .B IPTOS_LOWDELAY
to minimize delays for interactive traffic, to minimize delays for interactive traffic,
@ -551,8 +558,8 @@ option.
.TP .TP
.B IP_MTU .B IP_MTU
Retrieve the current known path MTU of the current socket. Retrieve the current known path MTU of the current socket.
Only valid when the socket has been connected. Returns an integer. Only valid Only valid when the socket has been connected. Returns an integer.
as a Only valid as a
.BR getsockopt (2). .BR getsockopt (2).
.\" .\"
.TP .TP
@ -560,9 +567,12 @@ as a
Pass all to-be forwarded packets with the Pass all to-be forwarded packets with the
IP Router Alert IP Router Alert
option option
set to this socket. Only valid for raw sockets. This is useful, for instance, for user set to this socket. Only valid for raw sockets.
space RSVP daemons. The tapped packets are not forwarded by the kernel, it is This is useful, for instance, for user
the users responsibility to send them out again. Socket binding is ignored, space RSVP daemons.
The tapped packets are not forwarded by the kernel, it is
the users responsibility to send them out again.
Socket binding is ignored,
such packets are only filtered by protocol. such packets are only filtered by protocol.
Expects an integer flag. Expects an integer flag.
.\" .\"
@ -577,8 +587,8 @@ integer.
.\" .\"
.TP .TP
.B IP_MULTICAST_LOOP .B IP_MULTICAST_LOOP
Sets or reads a boolean integer argument whether sent multicast packets should be Sets or reads a boolean integer argument whether sent multicast
looped back to the local sockets. packets should be looped back to the local sockets.
.\" .\"
.TP .TP
.B IP_ADD_MEMBERSHIP .B IP_ADD_MEMBERSHIP
@ -598,10 +608,12 @@ struct ip_mreqn {
.RE .RE
.IP .IP
.I imr_multiaddr .I imr_multiaddr
contains the address of the multicast group the application wants to join or leave. contains the address of the multicast group the application
wants to join or leave.
It must be a valid multicast address. It must be a valid multicast address.
.I imr_address .I imr_address
is the address of the local interface with which the system should join the multicast is the address of the local interface with which the system
should join the multicast
group; if it is equal to group; if it is equal to
.B INADDR_ANY .B INADDR_ANY
an appropriate interface is chosen by the system. an appropriate interface is chosen by the system.
@ -696,13 +708,14 @@ option.
.TP .TP
.BR ip_dynaddr " (Boolean; default: disabled)" .BR ip_dynaddr " (Boolean; default: disabled)"
Enable dynamic socket address and masquerading entry rewriting on interface Enable dynamic socket address and masquerading entry rewriting on interface
address change. This is useful for dialup interface with changing IP addresses. address change.
This is useful for dialup interface with changing IP addresses.
0 means no rewriting, 1 turns it on and 2 enables verbose mode. 0 means no rewriting, 1 turns it on and 2 enables verbose mode.
.\" .\"
.TP .TP
.BR ip_forward " (Boolean; default: disabled)" .BR ip_forward " (Boolean; default: disabled)"
Enable IP forwarding with a boolean flag. IP forwarding can be also set on a Enable IP forwarding with a boolean flag.
per interface basis. IP forwarding can be also set on a per interface basis.
.\" .\"
.TP .TP
.BR ip_local_port_range .BR ip_local_port_range
@ -790,7 +803,8 @@ received datagrams. Linux has the more general
for the same task. for the same task.
.PP .PP
.SH ERRORS .SH ERRORS
.\" XXX document all errors. We should really fix the kernels to give more uniform .\" XXX document all errors.
.\" We should really fix the kernels to give more uniform
.\" error returns (ENOMEM vs ENOBUFS, EPERM vs EACCES etc.) .\" error returns (ENOMEM vs ENOBUFS, EPERM vs EACCES etc.)
.TP .TP
.B ENOTCONN .B ENOTCONN