2 .\" Don't remove the line above, it tells man that tbl is needed.
3 .\" This man page is Copyright (C) 1999 Andi Kleen <ak@muc.de>.
4 .\" Permission is granted to distribute possibly modified copies
5 .\" of this page provided the header is included verbatim,
6 .\" and in case of nontrivial modification author and date
7 .\" of the modification is added to the header.
8 .\" Based on the original comments from Alexey Kuznetsov, written with
9 .\" help from Matthew Wilcox.
10 .\" $Id: rtnetlink.7,v 1.8 2000/01/22 01:55:04 freitag Exp $
11 .TH RTNETLINK 7 2008-08-08 "Linux" "Linux Programmer's Manual"
13 rtnetlink, NETLINK_ROUTE \- Linux IPv4 routing socket
15 .B #include <asm/types.h>
17 .B #include <linux/netlink.h>
19 .B #include <linux/rtnetlink.h>
21 .B #include <sys/socket.h>
23 .BI "rtnetlink_socket = socket(AF_NETLINK, int " socket_type ", NETLINK_ROUTE);"
25 Rtnetlink allows the kernel's routing tables to be read and altered.
26 It is used within the kernel to communicate between
27 various subsystems, though this usage is not documented here, and for
28 communication with user-space programs.
29 Network routes, IP addresses, link parameters, neighbor setups, queueing
30 disciplines, traffic classes and packet classifiers may all be controlled
34 It is based on netlink messages; see
37 .\" FIXME ? all these macros could be moved to rtnetlink(3)
38 .SS "Routing Attributes"
39 Some rtnetlink messages have optional attributes after the initial header:
44 unsigned short rta_len; /* Length of option */
45 unsigned short rta_type; /* Type of option */
51 These attributes should be only manipulated using the RTA_* macros
55 Rtnetlink consists of these message types
56 (in addition to standard netlink messages):
58 .BR RTM_NEWLINK ", " RTM_DELLINK ", " RTM_GETLINK
59 Create, remove or get information about a specific network interface.
60 These messages contain an
62 structure followed by a series of
68 unsigned char ifi_family; /* AF_UNSPEC */
69 unsigned short ifi_type; /* Device type */
70 int ifi_index; /* Interface index */
71 unsigned int ifi_flags; /* Device flags */
72 unsigned int ifi_change; /* change mask */
78 contains the device flags, see
81 is the unique interface index,
83 is reserved for future use and should be always set to 0xFFFFFFFF.
89 rta_type:value type:description
91 IFLA_UNSPEC:-:unspecified.
92 IFLA_ADDRESS:hardware address:interface L2 address
93 IFLA_BROADCAST:hardware address:L2 broadcast address.
94 IFLA_IFNAME:asciiz string:Device name.
95 IFLA_MTU:unsigned int:MTU of the device.
96 IFLA_LINK:int:Link type.
97 IFLA_QDISC:asciiz string:Queueing discipline.
100 T}:Interface Statistics.
103 The value type for IFLA_STATS is \fIstruct net_device_stats\fP.
105 .BR RTM_NEWADDR ", " RTM_DELADDR ", " RTM_GETADDR
106 Add, remove or receive information about an IP address associated with
108 In Linux 2.2, an interface can carry multiple IP addresses,
109 this replaces the alias device concept in 2.0.
110 In Linux 2.2, these messages
111 support IPv4 and IPv6 addresses.
114 structure, optionally followed by
120 unsigned char ifa_family; /* Address type */
121 unsigned char ifa_prefixlen; /* Prefixlength of address */
122 unsigned char ifa_flags; /* Address flags */
123 unsigned char ifa_scope; /* Address scope */
124 int ifa_index; /* Interface index */
129 is the address family type (currently
134 is the length of the address mask of the address if defined for the
135 family (like for IPv4),
137 is the address scope,
139 is the interface index of the interface the address is associated with.
143 for secondary address (old alias interface),
145 for a permanent address set by the user and other undocumented flags.
151 rta_type:value type:description
153 IFA_UNSPEC:-:unspecified.
154 IFA_ADDRESS:raw protocol address:interface address
155 IFA_LOCAL:raw protocol address:local address
156 IFA_LABEL:asciiz string:name of the interface
157 IFA_BROADCAST:raw protocol address:broadcast address.
158 IFA_ANYCAST:raw protocol address:anycast address
159 IFA_CACHEINFO:struct ifa_cacheinfo:Address information.
161 .\" FIXME struct ifa_cacheinfo
163 .BR RTM_NEWROUTE ", " RTM_DELROUTE ", " RTM_GETROUTE
164 Create, remove or receive information about a network route.
165 These messages contain an
167 structure with an optional sequence of
169 structures following.
176 to 0 means you get all entries for the specified routing table.
177 For the other fields, except
185 unsigned char rtm_family; /* Address family of route */
186 unsigned char rtm_dst_len; /* Length of destination */
187 unsigned char rtm_src_len; /* Length of source */
188 unsigned char rtm_tos; /* TOS filter */
190 unsigned char rtm_table; /* Routing table ID */
191 unsigned char rtm_protocol; /* Routing protocol; see below */
192 unsigned char rtm_scope; /* See below */
193 unsigned char rtm_type; /* See below */
195 unsigned int rtm_flags;
203 RTN_UNSPEC:unknown route
204 RTN_UNICAST:a gateway or direct route
205 RTN_LOCAL:a local interface route
207 a local broadcast route (sent as a broadcast)
210 a local broadcast route (sent as a unicast)
212 RTN_MULTICAST:a multicast route
213 RTN_BLACKHOLE:a packet dropping route
214 RTN_UNREACHABLE:an unreachable destination
215 RTN_PROHIBIT:a packet rejection route
216 RTN_THROW:continue routing lookup in another table
217 RTN_NAT:a network address translation rule
219 refer to an external resolver (not implemented)
225 rtm_protocol:Route origin.
227 RTPROT_UNSPEC:unknown
229 by an ICMP redirect (currently unused)
231 RTPROT_KERNEL:by the kernel
232 RTPROT_BOOT:during boot
233 RTPROT_STATIC:by the administrator
238 are not interpreted by the kernel, they are just for user information.
239 They may be used to tag the source of a routing information or to
240 distinguish between multiple routing daemons.
242 .I <linux/rtnetlink.h>
243 for the routing daemon identifiers which are already assigned.
246 is the distance to the destination:
250 RT_SCOPE_UNIVERSE:global route
252 interior route in the local autonomous system
254 RT_SCOPE_LINK:route on this link
255 RT_SCOPE_HOST:route on the local host
256 RT_SCOPE_NOWHERE:destination doesn't exist
263 are available to the user.
267 have the following meanings:
272 if the route changes, notify the user via rtnetlink
274 RTM_F_CLONED:route is cloned from another route
275 RTM_F_EQUALIZE:a multipath equalizer (not yet implemented)
279 specifies the routing table
283 RT_TABLE_UNSPEC:an unspecified routing table
284 RT_TABLE_DEFAULT:the default table
285 RT_TABLE_MAIN:the main table
286 RT_TABLE_LOCAL:the local table
289 The user may assign arbitrary values between
292 .BR RT_TABLE_DEFAULT .
298 rta_type:value type:description
300 RTA_UNSPEC:-:ignored.
301 RTA_DST:protocol address:Route destination address.
302 RTA_SRC:protocol address:Route source address.
303 RTA_IIF:int:Input interface index.
304 RTA_OIF:int:Output interface index.
305 RTA_GATEWAY:protocol address:The gateway of the route
306 RTA_PRIORITY:int:Priority of route.
308 RTA_METRICS:int:Route metric
315 .B Fill these values in!
317 .BR RTM_NEWNEIGH ", " RTM_DELNEIGH ", " RTM_GETNEIGH
318 Add, remove or receive information about a neighbor table
319 entry (e.g., an ARP entry).
320 The message contains an
326 unsigned char ndm_family;
327 int ndm_ifindex; /* Interface index */
328 __u16 ndm_state; /* State */
329 __u8 ndm_flags; /* Flags */
333 struct nda_cacheinfo {
342 is a bit mask of the following states:
346 NUD_INCOMPLETE:a currently resolving cache entry
347 NUD_REACHABLE:a confirmed working cache entry
348 NUD_STALE:an expired cache entry
349 NUD_DELAY:an entry waiting for a timer
350 NUD_PROBE:a cache entry that is currently reprobed
351 NUD_FAILED:an invalid cache entry
352 NUD_NOARP:a device with no destination cache
353 NUD_PERMANENT:a static entry
362 NTF_PROXY:a proxy arp entry
363 NTF_ROUTER:an IPv6 router
367 .\" document the members of the struct better
370 struct has the following meanings for the
376 NDA_UNSPEC:unknown type
377 NDA_DST:a neighbor cache n/w layer destination address
378 NDA_LLADDR:a neighbor cache link layer address
379 NDA_CACHEINFO:cache statistics.
387 .I struct nda_cacheinfo
390 .BR RTM_NEWRULE ", " RTM_DELRULE ", " RTM_GETRULE
391 Add, delete or retrieve a routing rule.
395 .BR RTM_NEWQDISC ", " RTM_DELQDISC ", " RTM_GETQDISC
396 Add, remove or get a queueing discipline.
397 The message contains a
399 and may be followed by a series of
404 unsigned char tcm_family;
405 int tcm_ifindex; /* interface index */
406 __u32 tcm_handle; /* Qdisc handle */
407 __u32 tcm_parent; /* Parent qdisc */
416 rta_type:value type:Description
418 TCA_UNSPEC:-:unspecified
419 TCA_KIND:asciiz string:Name of queueing discipline
420 TCA_OPTIONS:byte sequence:Qdisc-specific options follow
421 TCA_STATS:struct tc_stats:Qdisc statistics.
422 TCA_XSTATS:qdisc specific:Module-specific statistics.
423 TCA_RATE:struct tc_estimator:Rate limit.
426 In addition various other qdisc module specific attributes are allowed.
427 For more information see the appropriate include files.
429 .BR RTM_NEWTCLASS ", " RTM_DELTCLASS ", " RTM_GETTCLASS
430 Add, remove or get a traffic class.
431 These messages contain a
435 .BR RTM_NEWTFILTER ", " RTM_DELTFILTER ", " RTM_GETTFILTER
436 Add, remove or receive information about a traffic filter.
437 These messages contain a
442 is a new feature of Linux 2.2.
444 This manual page is incomplete.