540 lines
16 KiB
Groff
540 lines
16 KiB
Groff
.\"
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.\" Copyright (C) 2022 Alexander Chernikov <melifaro@FreeBSD.org>.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.Dd November 1, 2022
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.Dt RTNETLINK 4
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.Os
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.Sh NAME
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.Nm RTNetlink
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.Nd Network configuration-specific Netlink family
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.Sh SYNOPSIS
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.In netlink/netlink.h
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.In netlink/netlink_route.h
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.Ft int
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.Fn socket AF_NETLINK SOCK_RAW NETLINK_ROUTE
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.Sh DESCRIPTION
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The
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.Dv NETLINK_ROUTE
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family aims to be the primary configuration mechanism for all
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network-related tasks.
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Currently it supports configuring interfaces, interface addresses, routes,
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nexthops and arp/ndp neighbors.
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.Sh ROUTES
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All route configuration messages share the common header:
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.Bd -literal
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struct rtmsg {
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unsigned char rtm_family; /* address family */
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unsigned char rtm_dst_len; /* Prefix length */
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unsigned char rtm_src_len; /* Deprecated, set to 0 */
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unsigned char rtm_tos; /* Type of service (not used) */
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unsigned char rtm_table; /* deprecated, set to 0 */
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unsigned char rtm_protocol; /* Routing protocol id (RTPROT_) */
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unsigned char rtm_scope; /* Route distance (RT_SCOPE_) */
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unsigned char rtm_type; /* Route type (RTN_) */
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unsigned rtm_flags; /* Route flags (not supported) */
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};
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.Ed
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.Pp
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The
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.Va rtm_family
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specifies the route family to be operated on.
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Currently,
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.Dv AF_INET6
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and
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.Dv AF_INET
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are the only supported families.
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The route prefix length is stored in
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.Va rtm_dst_len
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.
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The caller should set the originator identity (one of the
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.Dv RTPROT_
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values) in
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.Va rtm_protocol
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.
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It is useful for users and for the application itself, allowing for easy
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identification of self-originated routes.
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The route scope has to be set via
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.Va rtm_scope
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field.
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The supported values are:
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.Bd -literal -offset indent -compact
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RT_SCOPE_UNIVERSE Global scope
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RT_SCOPE_LINK Link scope
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.Ed
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.Pp
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Route type needs to be set.
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The defined values are:
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.Bd -literal -offset indent -compact
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RTN_UNICAST Unicast route
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RTN_MULTICAST Multicast route
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RTN_BLACKHOLE Drops traffic towards destination
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RTN_PROHIBIT Drops traffic and sends reject
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.Ed
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.Pp
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The following messages are supported:
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.Ss RTM_NEWROUTE
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Adds a new route.
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All NL flags are supported.
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Extending a multipath route requires NLM_F_APPEND flag.
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.Ss RTM_DELROUTE
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Tries to delete a route.
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The route is specified using a combination of
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.Dv RTA_DST
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TLV and
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.Va rtm_dst_len .
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.Ss RTM_GETROUTE
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Fetches a single route or all routes in the current VNET, depending on the
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.Dv NLM_F_DUMP
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flag.
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Each route is reported as
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.Dv RTM_NEWROUTE
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message.
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The following filters are recognised by the kernel:
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.Pp
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.Bd -literal -offset indent -compact
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rtm_family required family or AF_UNSPEC
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RTA_TABLE fib number or RT_TABLE_UNSPEC to return all fibs
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.Ed
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.Ss TLVs
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.Bl -tag -width indent
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.It Dv RTA_DST
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(binary) IPv4/IPv6 address, depending on the
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.Va rtm_family .
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.It Dv RTA_OIF
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(uint32_t) transmit interface index.
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.It Dv RTA_GATEWAY
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(binary) IPv4/IPv6 gateway address, depending on the
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.Va rtm_family .
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.It Dv RTA_METRICS
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(nested) Container attribute, listing route properties.
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The only supported sub-attribute is
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.Dv RTAX_MTU , which stores path MTU as uint32_t.
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.It Dv RTA_MULTIPATH
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This attribute contains multipath route nexthops with their weights.
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These nexthops are represented as a sequence of
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.Va rtnexthop
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structures, each followed by
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.Dv RTA_GATEWAY
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or
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.Dv RTA_VIA
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attributes.
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.Bd -literal
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struct rtnexthop {
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unsigned short rtnh_len;
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unsigned char rtnh_flags;
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unsigned char rtnh_hops; /* nexthop weight */
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int rtnh_ifindex;
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};
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.Ed
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.Pp
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The
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.Va rtnh_len
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field specifies the total nexthop info length, including both
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.Va struct rtnexthop
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and the following TLVs.
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The
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.Va rtnh_hops
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field stores relative nexthop weight, used for load balancing between group
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members.
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The
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.Va rtnh_ifindex
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field contains the index of the transmit interface.
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.Pp
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The following TLVs can follow the structure:
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.Bd -literal -offset indent -compact
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RTA_GATEWAY IPv4/IPv6 nexthop address of the gateway
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RTA_VIA IPv6 nexthop address for IPv4 route
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RTA_KNH_ID Kernel-specific index of the nexthop
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.Ed
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.It Dv RTA_KNH_ID
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(uint32_t) (FreeBSD-specific) Auto-allocated kernel index of the nexthop.
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.It Dv RTA_RTFLAGS
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(uint32_t) (FreeBSD-specific) rtsock route flags.
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.It Dv RTA_TABLE
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(uint32_t) Fib number of the route.
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Default route table is
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.Dv RT_TABLE_MAIN .
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To explicitely specify "all tables" one needs to set the value to
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.Dv RT_TABLE_UNSPEC .
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.It Dv RTA_EXPIRES
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(uint32_t) seconds till path expiration.
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.It Dv RTA_NH_ID
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(uint32_t) useland nexthop or nexthop group index.
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.El
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.Ss Groups
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The following groups are defined:
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.Bd -literal -offset indent -compact
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RTNLGRP_IPV4_ROUTE Notifies on IPv4 route arrival/removal/change
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RTNLGRP_IPV6_ROUTE Notifies on IPv6 route arrival/removal/change
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.Ed
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.Sh NEXTHOPS
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All nexthop/nexthop group configuration messages share the common header:
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.Bd -literal
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struct nhmsg {
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unsigned char nh_family; /* transport family */
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unsigned char nh_scope; /* ignored on RX, filled by kernel */
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unsigned char nh_protocol; /* Routing protocol that installed nh */
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unsigned char resvd;
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unsigned int nh_flags; /* RTNH_F_* flags from route.h */
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};
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.Ed
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The
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.Va nh_family
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specificies the gateway address family.
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It can be different from route address family for IPv4 routes with IPv6
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nexthops.
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The
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.Va nh_protocol
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is similar to
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.Va rtm_protocol
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field, which designates originator application identity.
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.Pp
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The following messages are supported:
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.Ss RTM_NEWNEXTHOP
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Creates a new nexthop or nexthop group.
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.Ss RTM_DELNEXTHOP
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Deletes nexthop or nexthhop group.
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The required object is specified by the
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.Dv RTA_NH_ID
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attribute.
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.Ss RTM_GETNEXTHOP
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Fetches a single nexthop or all nexthops/nexthop groups, depending on the
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.Dv NLM_F_DUMP
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flag.
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The following filters are recognised by the kernel:
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.Pp
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.Bd -literal -offset indent -compact
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RTA_NH_ID nexthop or nexthtop group id
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NHA_GROUPS match only nexthtop groups
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.Ed
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.Ss TLVs
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.Bl -tag -width indent
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.It Dv RTA_NH_ID
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(uint32_t) Nexthhop index used to identify particular nexthop or nexthop group.
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Should be provided by userland at the nexthtop creation time.
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.It Dv NHA_GROUP
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This attribute designates the nexthtop group and contains all of its nexthtops
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and their relative weights.
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The attribute constists of a list of
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.Va nexthop_grp
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structures:
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.Bd -literal
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struct nexthop_grp {
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uint32_t id; /* nexhop userland index */
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uint8_t weight; /* weight of this nexthop */
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uint8_t resvd1;
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uint16_t resvd2;
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};
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.Ed
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.It Dv NHA_GROUP_TYPE
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(uint16_t) Nexthtop group type, set to one of the following types:
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.Bd -literal -offset indent -compact
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NEXTHOP_GRP_TYPE_MPATH default multipath group
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.Ed
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.It Dv NHA_BLACKHOLE
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(flag) Marks the nexthtop as blackhole.
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.It Dv NHA_OIF
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(uint32_t) Transmit interface index of the nexthtop.
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.It Dv NHA_GATEWAY
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(binary) IPv4/IPv6 gateway address
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.It Dv NHA_GROUPS
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(flag) Matches nexthtop groups during dump.
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.El
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.Ss Groups
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The following groups are defined:
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.Bd -literal -offset indent -compact
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RTNLGRP_NEXTHOP Notifies on nexthop/groups arrival/removal/change
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.Ed
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.Sh INTERFACES
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All interface configuration messages share the common header:
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.Bd -literal
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struct ifinfomsg {
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unsigned char ifi_family; /* not used, set to 0 */
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unsigned char __ifi_pad;
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unsigned short ifi_type; /* ARPHRD_* */
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int ifi_index; /* Inteface index */
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unsigned ifi_flags; /* IFF_* flags */
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unsigned ifi_change; /* IFF_* change mask */
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};
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.Ed
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.Ss RTM_NEWLINK
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Creates a new interface.
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The only mandatory TLV is
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.Dv IFLA_IFNAME .
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The following attributes are returned inside the nested
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.Dv NLMSGERR_ATTR_COOKIE :
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.Pp
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.Bd -literal -offset indent -compact
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IFLA_NEW_IFINDEX (uint32) created interface index
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IFLA_IFNAME (string) created interface name
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.Ed
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.Ss RTM_DELLINK
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Deletes the interface specified by
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.Dv IFLA_IFNAME .
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.Ss RTM_GETLINK
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Fetches a single interface or all interfaces in the current VNET, depending on the
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.Dv NLM_F_DUMP
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flag.
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Each interface is reported as a
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.Dv RTM_NEWLINK
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message.
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The following filters are recognised by the kernel:
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.Pp
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.Bd -literal -offset indent -compact
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ifi_index interface index
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IFLA_IFNAME interface name
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IFLA_ALT_IFNAME interface name
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.Ed
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.Ss TLVs
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.Bl -tag -width indent
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.It Dv IFLA_ADDRESS
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(binary) Llink-level interface address (MAC).
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.It Dv IFLA_BROADCAST
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(binary) (readonly) Link-level broadcast address.
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.It Dv IFLA_IFNAME
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(string) New interface name.
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.It Dv IFLA_IFALIAS
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(string) Interface description.
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.It Dv IFLA_LINK
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(uint32_t) (readonly) Interface index.
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.It Dv IFLA_MASTER
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(uint32_t) Parent interface index.
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.It Dv IFLA_LINKINFO
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(nested) Interface type-specific attributes:
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.Bd -literal -offset indent -compact
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IFLA_INFO_KIND (string) interface type ("vlan")
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IFLA_INFO_DATA (nested) custom attributes
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.Ed
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The following types and attributes are supported:
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.Bl -tag -width indent
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.It Dv vlan
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.Bd -literal -offset indent -compact
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IFLA_VLAN_ID (uint16_t) 802.1Q vlan id
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IFLA_VLAN_PROTOCOL (uint16_t) Protocol: ETHERTYPE_VLAN or ETHERTYPE_QINQ
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.Ed
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.El
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.It Dv IFLA_OPERSTATE
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(uint8_t) Interface operational state per RFC 2863.
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Can be one of the following:
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.Bd -literal -offset indent -compact
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IF_OPER_UNKNOWN status can not be determined
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IF_OPER_NOTPRESENT some (hardware) component not present
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IF_OPER_DOWN down
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IF_OPER_LOWERLAYERDOWN some lower-level interface is down
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IF_OPER_TESTING in some test mode
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IF_OPER_DORMANT "up" but waiting for some condition (802.1X)
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IF_OPER_UP ready to pass packets
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.Ed
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.It Dv IFLA_STATS64
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(readonly) Consists of the following 64-bit counters structure:
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.Bd -literal
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struct rtnl_link_stats64 {
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uint64_t rx_packets; /* total RX packets (IFCOUNTER_IPACKETS) */
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uint64_t tx_packets; /* total TX packets (IFCOUNTER_OPACKETS) */
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uint64_t rx_bytes; /* total RX bytes (IFCOUNTER_IBYTES) */
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uint64_t tx_bytes; /* total TX bytes (IFCOUNTER_OBYTES) */
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uint64_t rx_errors; /* RX errors (IFCOUNTER_IERRORS) */
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uint64_t tx_errors; /* RX errors (IFCOUNTER_OERRORS) */
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uint64_t rx_dropped; /* RX drop (no space in ring/no bufs) (IFCOUNTER_IQDROPS) */
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uint64_t tx_dropped; /* TX drop (IFCOUNTER_OQDROPS) */
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uint64_t multicast; /* RX multicast packets (IFCOUNTER_IMCASTS) */
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uint64_t collisions; /* not supported */
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uint64_t rx_length_errors; /* not supported */
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uint64_t rx_over_errors; /* not supported */
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uint64_t rx_crc_errors; /* not supported */
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uint64_t rx_frame_errors; /* not supported */
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uint64_t rx_fifo_errors; /* not supported */
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uint64_t rx_missed_errors; /* not supported */
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uint64_t tx_aborted_errors; /* not supported */
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uint64_t tx_carrier_errors; /* not supported */
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uint64_t tx_fifo_errors; /* not supported */
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uint64_t tx_heartbeat_errors; /* not supported */
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uint64_t tx_window_errors; /* not supported */
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uint64_t rx_compressed; /* not supported */
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uint64_t tx_compressed; /* not supported */
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uint64_t rx_nohandler; /* dropped due to no proto handler (IFCOUNTER_NOPROTO) */
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};
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.Ed
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.El
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.Ss Groups
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The following groups are defined:
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.Bd -literal -offset indent -compact
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RTNLGRP_LINK Notifies on interface arrival/removal/change
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.Ed
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.Sh INTERFACE ADDRESSES
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All interface address configuration messages share the common header:
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.Bd -literal
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struct ifaddrmsg {
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uint8_t ifa_family; /* Address family */
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uint8_t ifa_prefixlen; /* Prefix length */
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uint8_t ifa_flags; /* Address-specific flags */
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uint8_t ifa_scope; /* Address scope */
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uint32_t ifa_index; /* Link ifindex */
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};
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.Ed
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.Pp
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The
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.Va ifa_family
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specifies the address family of the interface address.
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The
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.Va ifa_prefixlen
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specifies the prefix length if applicable for the address family.
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The
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.Va ifa_index
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specifies the interface index of the target interface.
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.Ss RTM_NEWADDR
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Not supported
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.Ss RTM_DELADDR
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Not supported
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.Ss RTM_GETADDR
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Fetches interface addresses in the current VNET matching conditions.
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Each address is reported as a
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.Dv RTM_NEWADDR
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message.
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The following filters are recognised by the kernel:
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.Pp
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.Bd -literal -offset indent -compact
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ifa_family required family or AF_UNSPEC
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ifa_index matching interface index or 0
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.Ed
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.Ss TLVs
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.Bl -tag -width indent
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.It Dv IFA_ADDRESS
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(binary) masked interface address or destination address for p2p interfaces.
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.It Dv IFA_LOCAL
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(binary) local interface address.
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Set for IPv4 and p2p addresses.
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.It Dv IFA_LABEL
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(string) interface name.
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.It Dv IFA_BROADCAST
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(binary) broacast interface address.
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.El
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.Ss Groups
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The following groups are defined:
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.Bd -literal -offset indent -compact
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RTNLGRP_IPV4_IFADDR Notifies on IPv4 ifaddr arrival/removal/change
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RTNLGRP_IPV6_IFADDR Notifies on IPv6 ifaddr arrival/removal/change
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.Ed
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.Sh NEIGHBORS
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All neighbor configuration messages share the common header:
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.Bd -literal
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struct ndmsg {
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uint8_t ndm_family;
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uint8_t ndm_pad1;
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uint16_t ndm_pad2;
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int32_t ndm_ifindex;
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uint16_t ndm_state;
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uint8_t ndm_flags;
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uint8_t ndm_type;
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};
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.Ed
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.Pp
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The
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.Va ndm_family
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field specifies the address family (IPv4 or IPv6) of the neighbor.
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The
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.Va ndm_ifindex
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specifies the interface to operate on.
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The
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.Va ndm_state
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represents the entry state according to the neighbor model.
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The state can be one of the following:
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.Bd -literal -offset indent -compact
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NUD_INCOMPLETE No lladdr, address resolution in progress
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NUD_REACHABLE reachable & recently resolved
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NUD_STALE has lladdr but it's stale
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NUD_DELAY has lladdr, is stale, probes delayed
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NUD_PROBE has lladdr, is stale, probes sent
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NUD_FAILED unused
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.Ed
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.Pp
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The
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.Va ndm_flags
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field stores the options specific to this entry.
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Available flags:
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.Bd -literal -offset indent -compact
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NTF_SELF local station (LLE_IFADDR)
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NTF_PROXY proxy entry (LLE_PUB)
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|
NTF_STICKY permament entry (LLE_STATIC)
|
|
NTF_ROUTER dst indicated itself as a router
|
|
.Ed
|
|
.Ss RTM_NEWNEIGH
|
|
Creates new neighbor entry.
|
|
The mandatory options are
|
|
.Dv NDA_DST ,
|
|
.Dv NDA_LLADDR
|
|
and
|
|
.Dv NDA_IFINDEX .
|
|
.Ss RTM_DELNEIGH
|
|
Deletes the neighbor entry.
|
|
The entry is specified by the combination of
|
|
.Dv NDA_DST
|
|
and
|
|
.Dv NDA_IFINDEX .
|
|
.Ss RTM_GETNEIGH
|
|
Fetches a single neighbor or all neighbors in the current VNET, depending on the
|
|
.Dv NLM_F_DUMP
|
|
flag.
|
|
Each entry is reported as
|
|
.Dv RTM_NEWNEIGH
|
|
message.
|
|
The following filters are recognised by the kernel:
|
|
.Pp
|
|
.Bd -literal -offset indent -compact
|
|
ndm_family required family or AF_UNSPEC
|
|
ndm_ifindex target ifindex
|
|
NDA_IFINDEX target ifindex
|
|
.Ed
|
|
.Ss TLVs
|
|
.Bl -tag -width indent
|
|
.It Dv NDA_DST
|
|
(binary) neighbor IPv4/IPv6 address.
|
|
.It Dv NDA_LLADDR
|
|
(binary) neighbor link-level address.
|
|
.It Dv NDA_IFINDEX
|
|
(uint32_t) interface index.
|
|
.It Dv NDA_FLAGS_EXT
|
|
(uint32_t) extended version of
|
|
.Va ndm_flags .
|
|
.El
|
|
.Ss Groups
|
|
The following groups are defined:
|
|
.Bd -literal -offset indent -compact
|
|
RTNLGRP_NEIGH Notifies on ARP/NDP neighbor arrival/removal/change
|
|
.Ed
|
|
.Sh SEE ALSO
|
|
.Xr netlink 4 ,
|
|
.Xr route 4
|
|
.Sh HISTORY
|
|
The
|
|
.Dv NETLINK_ROUTE
|
|
protocol family appeared in
|
|
.Fx 13.2 .
|
|
.Sh AUTHORS
|
|
The netlink was implementated by
|
|
.An -nosplit
|
|
.An Alexander Chernikov Aq Mt melifaro@FreeBSD.org .
|
|
It was derived from the Google Summer of Code 2021 project by
|
|
.An Ng Peng Nam Sean .
|