sock_diag.7: ffix

[thirdparty/man-pages.git] / man7 / rtnetlink.7

'\" t
.\" This man page is Copyright (C) 1999 Andi Kleen <ak@muc.de>.
.\"
.\" %%%LICENSE_START(VERBATIM_ONE_PARA)
.\" Permission is granted to distribute possibly modified copies
.\" of this page provided the header is included verbatim,
.\" and in case of nontrivial modification author and date
.\" of the modification is added to the header.
.\" %%%LICENSE_END
.\"
.\" Based on the original comments from Alexey Kuznetsov, written with
.\" help from Matthew Wilcox.
.\" $Id: rtnetlink.7,v 1.8 2000/01/22 01:55:04 freitag Exp $
.\"
.TH RTNETLINK  7 2013-03-05 "Linux" "Linux Programmer's Manual"
.SH NAME
rtnetlink \- Linux IPv4 routing socket
.SH SYNOPSIS
.B #include <asm/types.h>
.br
.B #include <linux/netlink.h>
.br
.B #include <linux/rtnetlink.h>
.br
.B #include <sys/socket.h>
.sp
.BI "rtnetlink_socket = socket(AF_NETLINK, int " socket_type ", NETLINK_ROUTE);"
.SH DESCRIPTION
Rtnetlink allows the kernel's routing tables to be read and altered.
It is used within the kernel to communicate between
various subsystems, though this usage is not documented here, and for
communication with user-space programs.
Network routes, IP addresses, link parameters, neighbor setups, queueing
disciplines, traffic classes and packet classifiers may all be controlled
through
.B NETLINK_ROUTE
sockets.
It is based on netlink messages; see
.BR netlink (7)
for more information.
.\" FIXME . ? all these macros could be moved to rtnetlink(3)
.SS Routing attributes
Some rtnetlink messages have optional attributes after the initial header:

.in +4n
.nf
struct rtattr {
    unsigned short rta_len;    /* Length of option */
    unsigned short rta_type;   /* Type of option */
    /* Data follows */
};
.fi
.in

These attributes should be manipulated using only the RTA_* macros
or libnetlink, see
.BR rtnetlink (3).
.SS Messages
Rtnetlink consists of these message types
(in addition to standard netlink messages):
.TP
.BR RTM_NEWLINK ", " RTM_DELLINK ", " RTM_GETLINK
Create, remove or get information about a specific network interface.
These messages contain an
.I ifinfomsg
structure followed by a series of
.I rtattr
structures.

.nf
struct ifinfomsg {
    unsigned char  ifi_family; /* AF_UNSPEC */
    unsigned short ifi_type;   /* Device type */
    int            ifi_index;  /* Interface index */
    unsigned int   ifi_flags;  /* Device flags  */
    unsigned int   ifi_change; /* change mask */
};
.fi

.\" FIXME Document ifinfomsg.ifi_type
.I ifi_flags
contains the device flags, see
.BR netdevice (7);
.I ifi_index
is the unique interface index
(since Linux 3.7, it is possible to feed a nonzero value with the
.B RTM_NEWLINK
message, thus creating a link with the given
.IR ifindex );
.I ifi_change
is reserved for future use and should be always set to 0xFFFFFFFF.
.TS
tab(:);
c s s
l l l.
Routing attributes
rta_type:value type:description
_
IFLA_UNSPEC:-:unspecified.
IFLA_ADDRESS:hardware address:interface L2 address
IFLA_BROADCAST:hardware address:L2 broadcast address.
IFLA_IFNAME:asciiz string:Device name.
IFLA_MTU:unsigned int:MTU of the device.
IFLA_LINK:int:Link type.
IFLA_QDISC:asciiz string:Queueing discipline.
IFLA_STATS:T{
see below
T}:Interface Statistics.
.TE
.sp
The value type for
.B IFLA_STATS
is
.IR "struct rtnl_link_stats"
.RI ( "struct net_device_stats"
in Linux 2.4 and earlier).
.TP
.BR RTM_NEWADDR ", " RTM_DELADDR ", " RTM_GETADDR
Add, remove or receive information about an IP address associated with
an interface.
In Linux 2.2, an interface can carry multiple IP addresses,
this replaces the alias device concept in 2.0.
In Linux 2.2, these messages
support IPv4 and IPv6 addresses.
They contain an
.I ifaddrmsg
structure, optionally followed by
.I rtattr
routing attributes.

.nf
struct ifaddrmsg {
    unsigned char ifa_family;    /* Address type */
    unsigned char ifa_prefixlen; /* Prefixlength of address */
    unsigned char ifa_flags;     /* Address flags */
    unsigned char ifa_scope;     /* Address scope */
    int           ifa_index;     /* Interface index */
};
.fi

.I ifa_family
is the address family type (currently
.B AF_INET
or
.BR AF_INET6 ),
.I ifa_prefixlen
is the length of the address mask of the address if defined for the
family (like for IPv4),
.I ifa_scope
is the address scope,
.I ifa_index
is the interface index of the interface the address is associated with.
.I ifa_flags
is a flag word of
.B IFA_F_SECONDARY
for secondary address (old alias interface),
.B IFA_F_PERMANENT
for a permanent address set by the user and other undocumented flags.
.TS
tab(:);
c s s
l l l.
Attributes
rta_type:value type:description
_
IFA_UNSPEC:-:unspecified.
IFA_ADDRESS:raw protocol address:interface address
IFA_LOCAL:raw protocol address:local address
IFA_LABEL:asciiz string:name of the interface
IFA_BROADCAST:raw protocol address:broadcast address.
IFA_ANYCAST:raw protocol address:anycast address
IFA_CACHEINFO:struct ifa_cacheinfo:Address information.
.TE
.\" FIXME Document struct ifa_cacheinfo
.TP
.BR RTM_NEWROUTE ", " RTM_DELROUTE ", " RTM_GETROUTE
Create, remove or receive information about a network route.
These messages contain an
.I rtmsg
structure with an optional sequence of
.I rtattr
structures following.
For
.BR RTM_GETROUTE ,
setting
.I rtm_dst_len
and
.I rtm_src_len
to 0 means you get all entries for the specified routing table.
For the other fields, except
.I rtm_table
and
.IR rtm_protocol ,
0 is the wildcard.

.nf
struct rtmsg {
    unsigned char rtm_family;   /* Address family of route */