svcadm(8)을 검색하려면 섹션에서 8 을 선택하고, 맨 페이지 이름에 svcadm을 입력하고 검색을 누른다.
rtnetlink(7)
RTNETLINK(7) Linux Programmer's Manual RTNETLINK(7)
NAME
rtnetlink - Linux IPv4 routing socket
SYNOPSIS
#include <asm/types.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <sys/socket.h>
rtnetlink_socket = socket(AF_NETLINK, int socket_type, NETLINK_ROUTE);
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 clas‐
sifiers may all be controlled through NETLINK_ROUTE sockets. It is
based on netlink messages; see netlink(7) for more information.
Routing attributes
Some rtnetlink messages have optional attributes after the initial
header:
struct rtattr {
unsigned short rta_len; /* Length of option */
unsigned short rta_type; /* Type of option */
/* Data follows */
};
These attributes should be manipulated using only the RTA_* macros or
libnetlink, see rtnetlink(3).
Messages
Rtnetlink consists of these message types (in addition to standard
netlink messages):
RTM_NEWLINK, RTM_DELLINK, RTM_GETLINK
Create, remove or get information about a specific network
interface. These messages contain an ifinfomsg structure fol‐
lowed by a series of rtattr structures.
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 */
};
ifi_flags contains the device flags, see netdevice(7); ifi_index
is the unique interface index (since Linux 3.7, it is possible
to feed a nonzero value with the RTM_NEWLINK message, thus cre‐
ating a link with the given ifindex); ifi_change is reserved for
future use and should be always set to 0xFFFFFFFF.
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_BROAD‐
CAST: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 dis‐
cipline. IFLA_STATS:T{ see below T}:Interface Statistics.
The value type for IFLA_STATS is struct rtnl_link_stats (struct
net_device_stats in Linux 2.4 and earlier).
RTM_NEWADDR, RTM_DELADDR, RTM_GETADDR
Add, remove or receive information about an IP address associ‐
ated 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 ifaddrmsg structure, optionally fol‐
lowed by rtattr routing attributes.
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 */
};
ifa_family is the address family type (currently AF_INET or
AF_INET6), ifa_prefixlen is the length of the address mask of
the address if defined for the family (like for IPv4), ifa_scope
is the address scope, ifa_index is the interface index of the
interface the address is associated with. ifa_flags is a flag
word of IFA_F_SECONDARY for secondary address (old alias inter‐
face), IFA_F_PERMANENT for a permanent address set by the user
and other undocumented flags.
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_BROAD‐
CAST:raw protocol address:broadcast address. IFA_ANYCAST:raw
protocol address:anycast address IFA_CACHEINFO:struct ifa_cache‐
info:Address information.
RTM_NEWROUTE, RTM_DELROUTE, RTM_GETROUTE
Create, remove or receive information about a network route.
These messages contain an rtmsg structure with an optional
sequence of rtattr structures following. For RTM_GETROUTE, set‐
ting rtm_dst_len and rtm_src_len to 0 means you get all entries
for the specified routing table. For the other fields, except
rtm_table and rtm_protocol, 0 is the wildcard.
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;
};
tab(:); l l. rtm_type:Route type _ RTN_UNSPEC:unknown route
RTN_UNICAST:a gateway or direct route RTN_LOCAL:a local inter‐
face route RTN_BROADCAST:T{ a local broadcast route (sent as a
broadcast) T} RTN_ANYCAST:T{ a local broadcast route (sent as a
unicast) T} RTN_MULTICAST:a multicast route RTN_BLACKHOLE:a
packet dropping route RTN_UNREACHABLE:an unreachable destination
RTN_PROHIBIT:a packet rejection route RTN_THROW:continue routing
lookup in another table RTN_NAT:a network address translation
rule RTN_XRESOLVE:T{ refer to an external resolver (not imple‐
mented) T}
tab(:); l l. rtm_protocol:Route origin. _
RTPROT_UNSPEC:unknown RTPROT_REDIRECT:T{ by an ICMP redirect
(currently unused) T} RTPROT_KERNEL:by the kernel
RTPROT_BOOT:during boot RTPROT_STATIC:by the administrator
Values larger than RTPROT_STATIC are not interpreted by the ker‐
nel, 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 <linux/rtnetlink.h> for
the routing daemon identifiers which are already assigned.
rtm_scope is the distance to the destination:
tab(:); l l. RT_SCOPE_UNIVERSE:global route RT_SCOPE_SITE:T{
interior route in the local autonomous system T}
RT_SCOPE_LINK:route on this link RT_SCOPE_HOST:route on the
local host RT_SCOPE_NOWHERE:destination doesn't exist
The values between RT_SCOPE_UNIVERSE and RT_SCOPE_SITE are
available to the user.
The rtm_flags have the following meanings:
tab(:); l l. RTM_F_NOTIFY:T{ if the route changes, notify the
user via rtnetlink T} RTM_F_CLONED:route is cloned from another
route RTM_F_EQUALIZE:a multipath equalizer (not yet implemented)
rtm_table specifies the routing table
tab(:); l l. RT_TABLE_UNSPEC:an unspecified routing table
RT_TABLE_DEFAULT:the default table RT_TABLE_MAIN:the main table
RT_TABLE_LOCAL:the local table
The user may assign arbitrary values between RT_TABLE_UNSPEC and
RT_TABLE_DEFAULT.
tab(:); c s s l l l. Attributes rta_type:value type:description
_ RTA_UNSPEC:-:ignored. RTA_DST:protocol address:Route destina‐
tion 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_MET‐
RICS:int:Route metric RTA_MULTIPATH:: RTA_PROTOINFO:: RTA_FLOW::
RTA_CACHEINFO::
Fill these values in!
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 ndmsg structure.
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;
};
ndm_state is a bit mask of the following states:
tab(:); l l. NUD_INCOMPLETE:a currently resolving cache entry
NUD_REACHABLE:a confirmed working cache entry NUD_STALE:an
expired cache entry NUD_DELAY:an entry waiting for a timer
NUD_PROBE:a cache entry that is currently reprobed NUD_FAILED:an
invalid cache entry NUD_NOARP:a device with no destination cache
NUD_PERMANENT:a static entry
Valid ndm_flags are:
tab(:); l l. NTF_PROXY:a proxy arp entry NTF_ROUTER:an IPv6
router
The rtattr struct has the following meanings for the rta_type
field:
tab(:); l l. 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.
If the rta_type field is NDA_CACHEINFO, then a struct nda_cache‐
info header follows
RTM_NEWRULE, RTM_DELRULE, RTM_GETRULE
Add, delete or retrieve a routing rule. Carries a struct rtmsg
RTM_NEWQDISC, RTM_DELQDISC, RTM_GETQDISC
Add, remove or get a queueing discipline. The message contains
a struct tcmsg and may be followed by a series of attributes.
struct tcmsg {
unsigned char tcm_family;
int tcm_ifindex; /* interface index */
__u32 tcm_handle; /* Qdisc handle */
__u32 tcm_parent; /* Parent qdisc */
__u32 tcm_info;
};
tab(:); c s s l2 l2 l. Attributes rta_type:value type:Descrip‐
tion _ 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.
In addition, various other qdisc-module-specific attributes are
allowed. For more information see the appropriate include
files.
RTM_NEWTCLASS, RTM_DELTCLASS, RTM_GETTCLASS
Add, remove or get a traffic class. These messages contain a
struct tcmsg as described above.
RTM_NEWTFILTER, RTM_DELTFILTER, RTM_GETTFILTER
Add, remove or receive information about a traffic filter.
These messages contain a struct tcmsg as described above.
VERSIONS
rtnetlink is a new feature of Linux 2.2.
BUGS
This manual page is incomplete.
SEE ALSO
cmsg(3), rtnetlink(3), ip(7), netlink(7)
COLOPHON
This page is part of release 5.02 of the Linux man-pages project. A
description of the project, information about reporting bugs, and the
latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.
Linux 2017-09-15 RTNETLINK(7)