'\" t
-.\" Don't remove the line above, it tells man that tbl is needed.
.\" 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.
+.\" help from Matthew Wilcox.
.\" $Id: rtnetlink.7,v 1.8 2000/01/22 01:55:04 freitag Exp $
-.TH RTNETLINK 7 1999-04-30 "Linux Man Page" "Linux Programmer's Manual"
+.\"
+.TH RTNETLINK 7 2017-09-15 "Linux" "Linux Programmer's Manual"
.SH NAME
-rtnetlink, NETLINK_ROUTE \- Linux IPv4 routing socket
+rtnetlink \- Linux IPv4 routing socket
.SH SYNOPSIS
.B #include <asm/types.h>
.br
.B #include <linux/rtnetlink.h>
.br
.B #include <sys/socket.h>
-
-.BI "rtnetlink_socket = socket(PF_NETLINK, int " socket_type ", NETLINK_ROUTE);"
-
+.PP
+.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.
+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
+various subsystems, though this usage is not documented here, and for
communication with user-space programs.
-Network routes, ip addresses, link parameters, neighbour setups, queueing
+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
+sockets.
+It is based on netlink messages; see
.BR netlink (7)
-for more information.
-
-.\" XXX: all these macros could be moved to rtnetlink(3)
-
-.SH "ROUTING ATTRIBUTES"
+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:
-
-.nf
-.ta 4 19 32
-struct rtattr
-{
- unsigned short rta_len; /* Length of option */
- unsigned short rta_type; /* Type of option */
- /* Data follows */
+.PP
+.in +4n
+.EX
+struct rtattr {
+ unsigned short rta_len; /* Length of option */
+ unsigned short rta_type; /* Type of option */
+ /* Data follows */
};
-.fi
-
-These attributes should be only manipulated using the RTA_* macros or libnetlink,
-see
+.EE
+.in
+.PP
+These attributes should be manipulated using only the RTA_* macros
+or libnetlink, see
.BR rtnetlink (3).
-
-.SH MESSAGES
+.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.
+Create, remove or get information about a specific network interface.
These messages contain an
-.B ifinfomsg
+.I ifinfomsg
structure followed by a series of
-.B rtattr
+.I rtattr
structures.
-
-.nf
-.ta 4 19 32
-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 */
+.IP
+.EX
+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
-
-.\" XXX ifi_type
-.B ifi_flags
+.EE
+.IP
+.\" FIXME Document ifinfomsg.ifi_type
+.I ifi_flags
contains the device flags, see
-.BR netdevice(7);
-.B ifi_index
-is the unique interface index,
-.B ifi_change
-is reserved for future use and should be always set to 0xFFFFFFFF.
-
-
+.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
+c s s
l l l.
Routing attributes
rta_type:value type:description
_
IFLA_UNSPEC:-:unspecified.
-IFLA_ADDRESS:hardware address:interface L2 address
+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{
-struct net_device_stats
+see below
T}:Interface Statistics.
.TE
-.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
-.B ifaddrmsg
+.PP
+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
-.B rtaddr
+.I rtattr
routing attributes.
-
-.nf
-.ta 4 19 32
-struct ifaddrmsg
-{
- unsigned char ifa_family; /* Address type */
- unsigned char ifa_prefixlen; /* Prefixlength of the address */
- unsigned char ifa_flags; /* Address flags */
- unsigned char ifa_scope; /* Address scope */
- int ifa_index; /* Interface index */
+.IP
+.EX
+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
-
-.B ifa_family
-is the address family type (currently
+.EE
+.IP
+.I ifa_family
+is the address family type (currently
.B AF_INET
or
-.B AF_INET6),
-.B ifa_prefixlen
-is the length of the address mask of the address if defined for the
-family (like for IPv4),
-.B ifa_scope
+.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,
-.B ifa_index
-is the interface index of the interface the address is associated with.
-.B ifa_flags
+.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),
+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
+c s s
l l l.
Attributes
rta_type:value type:description
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.
+IFA_CACHEINFO:struct ifa_cacheinfo:Address information.
.TE
-
-.\" XXX struct ifa_cacheinfo
-.TP
-.BR RTM_NEWROUTE ", " RTM_DELROUTE ", " RTM_GETROUTE
+.\" 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
-.B rtmsg
-structure with an optional sequence of
-.B rtattr
-structures following. For
-.B RTM_GETROUTE
-setting
-.B rtm_dst_len
-and
-.B rtm_src_len
+.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
-.B rtm_table
-and
-.B rtm_protocol
+For the other fields, except
+.I rtm_table
+and
+.IR rtm_protocol ,
0 is the wildcard.
-
-.nf
-.ta 4 19 32
-struct rtmsg
-{
- unsigned char rtm_family; /* Address family of route */
- unsigned char rtm_dst_len; /* Length of source */
- unsigned char rtm_src_len; /* Length of destination */
- unsigned char rtm_tos; /* TOS filter */
-
- unsigned char rtm_table; /* Routing table id */
- unsigned char rtm_protocol; /* Routing protocol; see below */
- unsigned char rtm_scope; /* See below */
- unsigned char rtm_type; /* See below */
-
- unsigned int rtm_flags;
+.IP
+.EX
+struct rtmsg {
+ unsigned char rtm_family; /* Address family of route */
+ unsigned char rtm_dst_len; /* Length of destination */
+ unsigned char rtm_src_len; /* Length of source */
+ unsigned char rtm_tos; /* TOS filter */
+
+ unsigned char rtm_table; /* Routing table ID */
+ unsigned char rtm_protocol; /* Routing protocol; see below */
+ unsigned char rtm_scope; /* See below */
+ unsigned char rtm_type; /* See below */
+
+ unsigned int rtm_flags;
};
-.fi
-
+.EE
.TS
tab(:);
-l l
l l.
rtm_type:Route type
_
refer to an external resolver (not implemented)
T}
.TE
-
.TS
tab(:);
l l.
RTPROT_BOOT:during boot
RTPROT_STATIC:by the administrator
.TE
-
+.sp 1
Values larger than
.B RTPROT_STATIC
-are not interpreted by the kernel, they are just for user information. They
-may be used to tag the source of a routing information or to distingush between
-multiple routing daemons. See
-.BR <linux/rtnetlink.h>
-for the routing daemon identifiers which are already assigned.
-
-.B rtm_scope
-is the distance to the destination:
-
+are not interpreted by the kernel, they are just for user information.
+They may be used to tag the source of a routing information or to
+distinguish between multiple routing daemons.
+See
+.I <linux/rtnetlink.h>
+for the routing daemon identifiers which are already assigned.
+.IP
+.I rtm_scope
+is the distance to the destination:
.TS
tab(:);
l l.
RT_SCOPE_HOST:route on the local host
RT_SCOPE_NOWHERE:destination doesn't exist
.TE
-
+.sp 1
The values between
.B RT_SCOPE_UNIVERSE
and
.B RT_SCOPE_SITE
are available to the user.
-
+.IP
The
-.B rtm_flags
+.I rtm_flags
have the following meanings:
-
.TS
tab(:);
l l.
if the route changes, notify the user via rtnetlink
T}
RTM_F_CLONED:route is cloned from another route
-RTM_F_EQUALIZE:a multicast equalizer (not yet implemented)
+RTM_F_EQUALIZE:a multipath equalizer (not yet implemented)
.TE
-
-.B rtm_table
+.sp 1
+.I rtm_table
specifies the routing table
-
.TS
tab(:);
l l.
RT_TABLE_MAIN:the main table
RT_TABLE_LOCAL:the local table
.TE
-
-The user may assign arbitary values between
+.sp 1
+The user may assign arbitrary values between
.B RT_TABLE_UNSPEC
and
.BR RT_TABLE_DEFAULT .
-
+.\" Keep table on same page
+.bp +1
.TS
tab(:);
-c
+c s s
l l l.
Attributes
rta_type:value type:description
RTA_FLOW::
RTA_CACHEINFO::
.TE
-
+.sp 1
.B Fill these values in!
-.TP
-.BR RTM_NEWNEIGH ", " RTM_DELNEIGH ", " RTM_GETNEIGH
-Add, remove or receive information about a neighbour table entry (e.g. an ARP
-entry). The message contains an
-.B ndmsg
+.TP
+.BR RTM_NEWNEIGH ", " RTM_DELNEIGH ", " RTM_GETNEIGH
+Add, remove or receive information about a neighbor table
+entry (e.g., an ARP entry).
+The message contains an
+.I ndmsg
structure.
-
-.nf
-.ta 4 19 32
-struct ndmsg
-{
- unsigned char ndm_family;
- int ndm_ifindex; /* Interface index */
- __u16 ndm_state; /* State */
- __u8 ndm_flags; /* Flags */
- __u8 ndm_type;
+.IP
+.EX
+struct ndmsg {
+ unsigned char ndm_family;
+ int ndm_ifindex; /* Interface index */
+ __u16 ndm_state; /* State */
+ __u8 ndm_flags; /* Flags */
+ __u8 ndm_type;
};
-struct nda_cacheinfo
-{
- __u32 ndm_confirmed;
- __u32 ndm_used;
- __u32 ndm_updated;
- __u32 ndm_refcnt;
+struct nda_cacheinfo {
+ __u32 ndm_confirmed;
+ __u32 ndm_used;
+ __u32 ndm_updated;
+ __u32 ndm_refcnt;
};
-.fi
-
-.B ndm_state
-is a bitmask of the following states:
-
+.EE
+.IP
+.I ndm_state
+is a bit mask of the following states:
.TS
tab(:);
l l.
NUD_NOARP:a device with no destination cache
NUD_PERMANENT:a static entry
.TE
-
+.sp 1
Valid
-.B ndm_flags
+.I ndm_flags
are:
-
.TS
tab(:);
l l.
NTF_PROXY:a proxy arp entry
NTF_ROUTER:an IPv6 router
.TE
-
-.B document the members of the struct better
-
+.sp 1
+.\" FIXME .
+.\" document the members of the struct better
The
-.B rtaddr
+.I rtattr
struct has the following meanings for the
-.B rta_type
+.I rta_type
field:
-
.TS
tab(:);
l l.
NDA_UNSPEC:unknown type
-NDA_DST:a neighbour cache network layer destination address
-NDA_LLADDR:a neighbour cache link layer address
+NDA_DST:a neighbor cache n/w layer destination address
+NDA_LLADDR:a neighbor cache link layer address
NDA_CACHEINFO:cache statistics.
.TE
-
+.sp 1
If the
-.B rta_type
+.I rta_type
field is
-.B NDA_CACHEINFO
+.BR NDA_CACHEINFO ,
then a
-.B struct nda_cacheinfo
+.I struct nda_cacheinfo
header follows
.TP
.BR RTM_NEWRULE ", " RTM_DELRULE ", " RTM_GETRULE
-Add, delete or retrieve a routing rule. Carries a
-.B struct rtmsg
+Add, delete or retrieve a routing rule.
+Carries a
+.I struct rtmsg
.TP
.BR RTM_NEWQDISC ", " RTM_DELQDISC ", " RTM_GETQDISC
-Add, remove or get a queueing discipline. The message contains a
-.B struct tcmsg
+Add, remove or get a queueing discipline.
+The message contains a
+.I struct tcmsg
and may be followed by a series of
attributes.
-
-.nf
-.ta 4 19 32
-struct tcmsg
-{
- unsigned char tcm_family;
- int tcm_ifindex; /* interface index */
- __u32 tcm_handle; /* Qdisc handle */
- __u32 tcm_parent; /* Parent qdisc */
- __u32 tcm_info;
+.IP
+.EX
+struct tcmsg {
+ unsigned char tcm_family;
+ int tcm_ifindex; /* interface index */
+ __u32 tcm_handle; /* Qdisc handle */
+ __u32 tcm_parent; /* Parent qdisc */
+ __u32 tcm_info;
};
-.fi
-
+.EE
.TS
tab(:);
-c
-l l l.
+c s s
+l2 l2 l.
Attributes
rta_type:value type:Description
_
TCA_UNSPEC:-:unspecified
TCA_KIND:asciiz string:Name of queueing discipline
-TCA_OPTIONS:byte sequence:Qdisc specific options follow
+TCA_OPTIONS:byte sequence:Qdisc-specific options follow
TCA_STATS:struct tc_stats:Qdisc statistics.
-TCA_XSTATS:qdisc specific:Module specific statistics.
+TCA_XSTATS:qdisc-specific:Module-specific statistics.
TCA_RATE:struct tc_estimator:Rate limit.
.TE
-
-In addition various other qdisc module specific attributes are allowed.
+.sp 1
+In addition, various other qdisc-module-specific attributes are allowed.
For more information see the appropriate include files.
.TP
.BR RTM_NEWTCLASS ", " RTM_DELTCLASS ", " RTM_GETTCLASS
-Add, remove or get a traffic class. These messages contain a
-.B struct tcmsg
+Add, remove or get a traffic class.
+These messages contain a
+.I struct tcmsg
as described above.
.TP
.BR RTM_NEWTFILTER ", " RTM_DELTFILTER ", " RTM_GETTFILTER
-Add, remove or receive information about a traffic filter. These
-messages contain a
-.B struct tcmsg
+Add, remove or receive information about a traffic filter.
+These messages contain a
+.I struct tcmsg
as described above.
.SH VERSIONS
-.B rtnetlink
+.B rtnetlink
is a new feature of Linux 2.2.
.SH BUGS
-This manual page is lacking and incomplete.
-
-.SH "SEE ALSO"
+This manual page is incomplete.
+.SH SEE ALSO
.BR cmsg (3),
.BR rtnetlink (3),
.BR ip (7),
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