.\" 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"
+.TH RTNETLINK 7 2020-02-09 "Linux" "Linux Programmer's Manual"
.SH NAME
rtnetlink \- Linux IPv4 routing socket
.SH SYNOPSIS
.B #include <linux/rtnetlink.h>
.br
.B #include <sys/socket.h>
-.sp
+.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.
It is based on netlink messages; see
.BR netlink (7)
for more information.
-.\" FIXME ? all these macros could be moved to rtnetlink(3)
+.\" FIXME . ? all these macros could be moved to rtnetlink(3)
.SS Routing attributes
Some rtnetlink messages have optional attributes after the initial header:
-
+.PP
.in +4n
-.nf
+.EX
struct rtattr {
unsigned short rta_len; /* Length of option */
unsigned short rta_type; /* Type of option */
/* Data follows */
};
-.fi
+.EE
.in
-
+.PP
These attributes should be manipulated using only the RTA_* macros
or libnetlink, see
.BR rtnetlink (3).
structure followed by a series of
.I rtattr
structures.
-
-.nf
+.IP
+.EX
struct ifinfomsg {
unsigned char ifi_family; /* AF_UNSPEC */
unsigned short ifi_type; /* Device type */
unsigned int ifi_flags; /* Device flags */
unsigned int ifi_change; /* change mask */
};
-.fi
-
-.\" FIXME ifi_type
+.EE
+.IP
+.\" FIXME Document ifinfomsg.ifi_type
.I ifi_flags
contains the device flags, see
.BR netdevice (7);
c s s
l l l.
Routing attributes
-rta_type:value type:description
+rta_type:Value type:Description
_
-IFLA_UNSPEC:-:unspecified.
+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_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.
+T}:Interface Statistics
.TE
-.sp
+.PP
The value type for
.B IFLA_STATS
is
structure, optionally followed by
.I rtattr
routing attributes.
-
-.nf
+.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 */
+ unsigned int ifa_index; /* Interface index */
};
-.fi
-
+.EE
+.IP
.I ifa_family
is the address family type (currently
.B AF_INET
c s s
l l l.
Attributes
-rta_type:value type:description
+rta_type:Value type:Description
_
-IFA_UNSPEC:-:unspecified.
+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_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
-.\" FIXME struct ifa_cacheinfo
+.\" FIXME Document struct ifa_cacheinfo
.TP
.BR RTM_NEWROUTE ", " RTM_DELROUTE ", " RTM_GETROUTE
Create, remove or receive information about a network route.
and
.IR rtm_protocol ,
0 is the wildcard.
-
-.nf
+.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_table; /* Routing table ID;
+ see RTA_TABLE below */
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.
.TS
tab(:);
l l.
-rtm_protocol:Route origin.
+rtm_protocol:Route origin
_
RTPROT_UNSPEC:unknown
RTPROT_REDIRECT:T{
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.
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
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
.I rtm_flags
have the following meanings:
RTM_F_CLONED:route is cloned from another route
RTM_F_EQUALIZE:a multipath equalizer (not yet implemented)
.TE
-
+.sp 1
.I rtm_table
specifies the routing table
.TS
RT_TABLE_MAIN:the main table
RT_TABLE_LOCAL:the local table
.TE
-
+.sp 1
The user may assign arbitrary values between
.B RT_TABLE_UNSPEC
and
.TS
tab(:);
c s s
-l l l.
+l2 l2 l.
Attributes
-rta_type:value type:description
+rta_type:Value type:Description
_
-RTA_UNSPEC:-:ignored.
-RTA_DST:protocol address:Route destination address.
-RTA_SRC:protocol address:Route source address.
-RTA_IIF:int:Input interface index.
-RTA_OIF:int:Output interface index.
+RTA_UNSPEC:-:ignored
+RTA_DST:protocol address:Route destination address
+RTA_SRC:protocol address:Route source address
+RTA_IIF:int:Input interface index
+RTA_OIF:int:Output interface index
RTA_GATEWAY:protocol address:The gateway of the route
-RTA_PRIORITY:int:Priority of route.
-RTA_PREFSRC::
+RTA_PRIORITY:int:Priority of route
+RTA_PREFSRC:protocol address:Preferred source address
RTA_METRICS:int:Route metric
-RTA_MULTIPATH::
-RTA_PROTOINFO::
-RTA_FLOW::
-RTA_CACHEINFO::
+RTA_MULTIPATH::T{
+Multipath nexthop data
+br
+(see below).
+T}
+RTA_PROTOINFO::No longer used
+RTA_FLOW:int:Route realm
+RTA_CACHEINFO:struct rta_cacheinfo:(see linux/rtnetlink.h)
+RTA_SESSION::No longer used
+RTA_MP_ALGO::No longer used
+RTA_TABLE:int:T{
+Routing table ID; if set,
+.br
+rtm_table is ignored
+T}
+RTA_MARK:int:
+RTA_MFC_STATS:struct rta_mfc_stats:(see linux/rtnetlink.h)
+RTA_VIA:struct rtvia:T{
+Gateway in different AF
+(see below)
+T}
+RTA_NEWDST:protocol address:T{
+Change packet
+destination address
+T}
+RTA_PREF:char:T{
+RFC4191 IPv6 router
+preference (see below)
+T}
+RTA_ENCAP_TYPE:short:T{
+Encapsulation type for
+.br
+lwtunnels (see below)
+T}
+RTA_ENCAP::Defined by RTA_ENCAP_TYPE
+RTA_EXPIRES:int:T{
+Expire time for IPv6
+routes (in seconds)
+T}
.TE
-
+.PP
+.I RTA_MULTIPATH
+contains several packed instances of
+.I struct rtnexthop
+together with nested RTAs
+.RB ( RTA_GATEWAY ):
+.PP
+.in +4n
+.EX
+struct rtnexthop {
+ unsigned short rtnh_len; /* Length of struct + length
+ of RTAs */
+ unsigned char rtnh_flags; /* Flags (see linux/rtnetlink.h) */
+ unsigned char rtnh_hops; /* Nexthop priority */
+ int rtnh_ifindex; /* Interface index for this
+ nexthop */
+}
+.EE
+.in
+.PP
+There exist a bunch of RTNH_* macros similar to RTA_* and NLHDR_* macros
+useful to handle these structures.
+.PP
+.nf
+.in +4n
+.EX
+struct rtvia {
+ unsigned short rtvia_family;
+ unsigned char rtvia_addr[0];
+};
+.EE
+.in
+.PP
+.I rtvia_addr
+is the address,
+.I rtvia_family
+is its family type.
+.PP
+.I RTA_PREF
+may contain values ICMPV6_ROUTER_PREF_LOW,
+ICMPV6_ROUTER_PREF_MEDIUM and
+ICMPV6_ROUTER_PREF_HIGH defined in <linux/icmpv6.h>
+.PP
+.I RTA_ENCAP_TYPE
+may contain values
+LWTUNNEL_ENCAP_MPLS, LWTUNNEL_ENCAP_IP,
+LWTUNNEL_ENCAP_ILA or LWTUNNEL_ENCAP_IP6
+defined in <linux/lwtunnel.h>.
+.sp 1
.B Fill these values in!
.TP
.BR RTM_NEWNEIGH ", " RTM_DELNEIGH ", " RTM_GETNEIGH
The message contains an
.I ndmsg
structure.
-
-.nf
+.IP
+.EX
struct ndmsg {
unsigned char ndm_family;
int ndm_ifindex; /* Interface index */
__u32 ndm_updated;
__u32 ndm_refcnt;
};
-.fi
-
+.EE
+.IP
.I ndm_state
is a bit mask of the following states:
.TS
NUD_NOARP:a device with no destination cache
NUD_PERMANENT:a static entry
.TE
-
+.sp 1
Valid
.I ndm_flags
are:
NTF_PROXY:a proxy arp entry
NTF_ROUTER:an IPv6 router
.TE
-
-.\" FIXME
+.sp 1
+.\" FIXME .
.\" document the members of the struct better
The
.I rtattr
NDA_UNSPEC:unknown type
NDA_DST:a neighbor cache n/w layer destination address
NDA_LLADDR:a neighbor cache link layer address
-NDA_CACHEINFO:cache statistics.
+NDA_CACHEINFO:cache statistics
.TE
-
+.sp 1
If the
.I rta_type
field is
-.B NDA_CACHEINFO
+.BR NDA_CACHEINFO ,
then a
.I struct nda_cacheinfo
header follows
.I struct tcmsg
and may be followed by a series of
attributes.
-
-.nf
+.IP
+.EX
struct tcmsg {
unsigned char tcm_family;
int tcm_ifindex; /* interface index */
__u32 tcm_parent; /* Parent qdisc */
__u32 tcm_info;
};
-.fi
+.EE
.TS
tab(:);
c s s
l2 l2 l.
Attributes
-rta_type:value type:Description
+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_STATS:struct tc_stats:Qdisc statistics.
-TCA_XSTATS:qdisc-specific:Module-specific statistics.
-TCA_RATE:struct tc_estimator:Rate limit.
+TCA_STATS:struct tc_stats:Qdisc statistics
+TCA_XSTATS:qdisc-specific:Module-specific statistics
+TCA_RATE:struct tc_estimator:Rate limit
.TE
-
+.sp 1
In addition, various other qdisc-module-specific attributes are allowed.
For more information see the appropriate include files.
.TP
projects / thirdparty / man-pages.git / blobdiff