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47f0bd5032
This patch adds a new protocol attribute to IPv4 and IPv6 addresses.
Inspiration was taken from the protocol attribute of routes. User space
applications like iproute2 can set/get the protocol with the Netlink API.
The attribute is stored as an 8-bit unsigned integer.
The protocol attribute is set by kernel for these categories:
- IPv4 and IPv6 loopback addresses
- IPv6 addresses generated from router announcements
- IPv6 link local addresses
User space may pass custom protocols, not defined by the kernel.
Grouping addresses on their origin is useful in scenarios where you want
to distinguish between addresses based on who added them, e.g. kernel
vs. user space.
Tagging addresses with a string label is an existing feature that could be
used as a solution. Unfortunately the max length of a label is
15 characters, and for compatibility reasons the label must be prefixed
with the name of the device followed by a colon. Since device names also
have a max length of 15 characters, only -1 characters is guaranteed to be
available for any origin tag, which is not that much.
A reference implementation of user space setting and getting protocols
is available for iproute2:
9a6ea18bd7
Signed-off-by: Jacques de Laval <Jacques.De.Laval@westermo.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20220217150202.80802-1-Jacques.De.Laval@westermo.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
79 lines
2.1 KiB
C
79 lines
2.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
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#ifndef __LINUX_IF_ADDR_H
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#define __LINUX_IF_ADDR_H
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#include <linux/types.h>
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#include <linux/netlink.h>
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struct ifaddrmsg {
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__u8 ifa_family;
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__u8 ifa_prefixlen; /* The prefix length */
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__u8 ifa_flags; /* Flags */
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__u8 ifa_scope; /* Address scope */
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__u32 ifa_index; /* Link index */
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};
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/*
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* Important comment:
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* IFA_ADDRESS is prefix address, rather than local interface address.
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* It makes no difference for normally configured broadcast interfaces,
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* but for point-to-point IFA_ADDRESS is DESTINATION address,
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* local address is supplied in IFA_LOCAL attribute.
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*
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* IFA_FLAGS is a u32 attribute that extends the u8 field ifa_flags.
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* If present, the value from struct ifaddrmsg will be ignored.
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*/
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enum {
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IFA_UNSPEC,
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IFA_ADDRESS,
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IFA_LOCAL,
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IFA_LABEL,
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IFA_BROADCAST,
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IFA_ANYCAST,
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IFA_CACHEINFO,
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IFA_MULTICAST,
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IFA_FLAGS,
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IFA_RT_PRIORITY, /* u32, priority/metric for prefix route */
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IFA_TARGET_NETNSID,
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IFA_PROTO, /* u8, address protocol */
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__IFA_MAX,
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};
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#define IFA_MAX (__IFA_MAX - 1)
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/* ifa_flags */
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#define IFA_F_SECONDARY 0x01
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#define IFA_F_TEMPORARY IFA_F_SECONDARY
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#define IFA_F_NODAD 0x02
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#define IFA_F_OPTIMISTIC 0x04
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#define IFA_F_DADFAILED 0x08
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#define IFA_F_HOMEADDRESS 0x10
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#define IFA_F_DEPRECATED 0x20
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#define IFA_F_TENTATIVE 0x40
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#define IFA_F_PERMANENT 0x80
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#define IFA_F_MANAGETEMPADDR 0x100
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#define IFA_F_NOPREFIXROUTE 0x200
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#define IFA_F_MCAUTOJOIN 0x400
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#define IFA_F_STABLE_PRIVACY 0x800
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struct ifa_cacheinfo {
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__u32 ifa_prefered;
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__u32 ifa_valid;
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__u32 cstamp; /* created timestamp, hundredths of seconds */
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__u32 tstamp; /* updated timestamp, hundredths of seconds */
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};
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/* backwards compatibility for userspace */
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#ifndef __KERNEL__
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#define IFA_RTA(r) ((struct rtattr*)(((char*)(r)) + NLMSG_ALIGN(sizeof(struct ifaddrmsg))))
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#define IFA_PAYLOAD(n) NLMSG_PAYLOAD(n,sizeof(struct ifaddrmsg))
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#endif
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/* ifa_proto */
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#define IFAPROT_UNSPEC 0
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#define IFAPROT_KERNEL_LO 1 /* loopback */
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#define IFAPROT_KERNEL_RA 2 /* set by kernel from router announcement */
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#define IFAPROT_KERNEL_LL 3 /* link-local set by kernel */
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#endif
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