linux/Documentation/networking
Alex Henrie f4bcbf360a net: ipv6/addrconf: clamp preferred_lft to the minimum required
If the preferred lifetime was less than the minimum required lifetime,
ipv6_create_tempaddr would error out without creating any new address.
On my machine and network, this error happened immediately with the
preferred lifetime set to 5 seconds or less, after a few minutes with
the preferred lifetime set to 6 seconds, and not at all with the
preferred lifetime set to 7 seconds. During my investigation, I found a
Stack Exchange post from another person who seems to have had the same
problem: They stopped getting new addresses if they lowered the
preferred lifetime below 3 seconds, and they didn't really know why.

The preferred lifetime is a preference, not a hard requirement. The
kernel does not strictly forbid new connections on a deprecated address,
nor does it guarantee that the address will be disposed of the instant
its total valid lifetime expires. So rather than disable IPv6 privacy
extensions altogether if the minimum required lifetime swells above the
preferred lifetime, it is more in keeping with the user's intent to
increase the temporary address's lifetime to the minimum necessary for
the current network conditions.

With these fixes, setting the preferred lifetime to 5 or 6 seconds "just
works" because the extra fraction of a second is practically
unnoticeable. It's even possible to reduce the time before deprecation
to 1 or 2 seconds by setting /proc/sys/net/ipv6/conf/*/regen_min_advance
and /proc/sys/net/ipv6/conf/*/dad_transmits to 0. I realize that that is
a pretty niche use case, but I know at least one person who would gladly
sacrifice performance and convenience to be sure that they are getting
the maximum possible level of privacy.

Link: https://serverfault.com/a/1031168/310447
Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-02-15 15:34:40 +01:00
..
caif tty: cumulate and document tty_struct::flow* members 2021-05-13 16:57:16 +02:00
device_drivers octeon_ep_vf: Add driver framework and device initialization 2024-02-12 09:01:52 +00:00
devlink Documentation: Fix counter name of mlx5 vnic reporter 2024-02-05 16:45:50 -08:00
dsa net: dsa: Rename IFLA_DSA_MASTER to IFLA_DSA_CONDUIT 2023-10-24 13:08:14 -07:00
mac80211_hwsim docs: net: convert two README files to ReST format 2019-07-31 13:31:56 -06:00
net_cachelines net-device: move xdp_prog to net_device_read_rx 2024-01-03 18:09:14 -08:00
netlink_spec Documentation: Document each netlink family 2023-11-24 01:16:56 +00:00
6lowpan.rst docs: networking: convert 6lowpan.txt to ReST 2020-02-28 14:52:36 +01:00
6pack.rst docs: networking: convert 6pack.txt to ReST 2020-04-28 14:38:38 -07:00
af_xdp.rst xsk: add multi-buffer documentation 2023-07-19 09:56:50 -07:00
alias.rst docs: networking: Convert alias.txt to rst 2018-07-18 15:28:27 -07:00
arcnet-hardware.rst Documentation: networking: correct spelling 2023-01-31 13:00:47 +01:00
arcnet.rst Documentation: networking: arcnet: drop doubled word 2020-07-04 17:46:21 -07:00
atm.rst docs: networking: convert atm.txt to ReST 2020-04-28 14:38:38 -07:00
ax25.rst Documentation: netdev: fix dead link in ax25.rst 2023-09-18 12:56:58 +01:00
bareudp.rst Documentation: bareudp: Corrected description of bareudp module. 2020-07-28 17:53:03 -07:00
batman-adv.rst batman-adv: Fix mailing list address 2023-01-21 19:01:59 +01:00
bonding.rst bonding: Add independent control state machine 2024-02-06 13:17:54 +01:00
bridge.rst docs: bridge: add other features 2023-12-05 10:48:01 +01:00
can_ucan_protocol.rst Documentation: networking: correct spelling 2023-01-31 13:00:47 +01:00
can.rst can: bcm: add recvmsg flags for own, local and remote traffic 2024-02-12 16:55:17 +01:00
cdc_mbim.rst Documentation: networking: correct spelling 2023-01-31 13:00:47 +01:00
checksum-offloads.rst docs: networking: convert netdev-features.txt to ReST 2020-04-30 12:56:36 -07:00
dccp.rst net: dccp: Add SIOCOUTQ IOCTL support (send buffer fill) 2020-07-22 17:00:37 -07:00
dctcp.rst docs: networking: convert dctcp.txt to ReST 2020-04-28 14:38:39 -07:00
dns_resolver.rst docs: networking: convert dns_resolver.txt to ReST 2020-04-28 14:39:46 -07:00
driver.rst net: docs: update the sample code in driver.rst 2023-04-13 13:30:21 +02:00
eql.rst docs: networking: convert eql.txt to ReST 2020-04-28 14:39:46 -07:00
ethtool-netlink.rst Revert "Introduce PHY listing and link_topology tracking" 2024-01-04 16:05:47 -08:00
failover.rst net: Introduce generic failover module 2018-05-28 22:59:54 -04:00
fib_trie.rst docs: networking: convert fib_trie.txt to ReST 2020-04-28 14:39:46 -07:00
filter.rst bpf, docs: Add loongarch64 as arch supporting BPF JIT 2023-09-21 15:30:09 -07:00
gen_stats.rst docs: networking: convert gen_stats.txt to ReST 2020-04-28 14:39:46 -07:00
generic_netlink.rst Documentation: networking: Update generic_netlink_howto URL 2022-11-23 17:25:02 -08:00
generic-hdlc.rst docs: networking: convert generic-hdlc.txt to ReST 2020-04-28 14:39:46 -07:00
gtp.rst Documentation: networking: correct spelling 2023-01-31 13:00:47 +01:00
ieee802154.rst Documentation: networking: correct spelling 2023-01-31 13:00:47 +01:00
ila.rst docs: networking: convert ila.txt to ReST 2020-04-28 14:39:47 -07:00
index.rst Revert "Introduce PHY listing and link_topology tracking" 2024-01-04 16:05:47 -08:00
ioam6-sysctl.rst ipv6: ioam: Documentation for new IOAM sysctls 2021-07-21 08:14:33 -07:00
ip_dynaddr.rst docs: networking: convert ip_dynaddr.txt to ReST 2020-04-28 14:39:47 -07:00
ip-sysctl.rst net: ipv6/addrconf: clamp preferred_lft to the minimum required 2024-02-15 15:34:40 +01:00
ipsec.rst docs: networking: convert ipsec.txt to ReST 2020-04-28 14:39:47 -07:00
ipv6.rst docs: networking: convert ipv6.txt to ReST 2020-04-28 14:40:18 -07:00
ipvlan.rst Documentation: networking: correct spelling 2023-01-31 13:00:47 +01:00
ipvs-sysctl.rst ipvs: run_estimation should control the kthread tasks 2022-12-10 22:44:43 +01:00
j1939.rst Documentation: networking: correct spelling 2023-01-31 13:00:47 +01:00
kapi.rst wimax: move out to staging 2020-10-29 19:27:45 +01:00
kcm.rst docs: networking: convert kcm.txt to ReST 2020-04-28 14:40:19 -07:00
l2tp.rst Documentation: networking: correct possessive "its" 2022-08-31 12:36:08 -07:00
lapb-module.rst docs: networking: convert lapb-module.txt to ReST 2020-04-30 12:56:35 -07:00
mac80211-auth-assoc-deauth.txt
mac80211-injection.rst doc: networking: wireless: fix wiki website url 2020-06-08 10:05:53 +02:00
mctp.rst mctp: Add SIOCMCTP{ALLOC,DROP}TAG ioctls for tag control 2022-02-09 12:00:11 +00:00
mpls-sysctl.rst docs: networking: convert mpls-sysctl.txt to ReST 2020-04-30 12:56:36 -07:00
mptcp-sysctl.rst mptcp: add a new sysctl for make after break timeout 2023-10-25 12:23:33 -07:00
msg_zerocopy.rst docs: net: description of MSG_ZEROCOPY for AF_VSOCK 2023-10-15 13:19:42 +01:00
multiqueue.rst docs: networking: convert multiqueue.txt to ReST 2020-04-30 12:56:36 -07:00
napi.rst docs: net: clarify the NAPI rules around XDP Tx 2023-07-21 18:51:37 -07:00
net_dim.rst docs: networking: add full DIM API 2020-04-10 18:11:04 -07:00
net_failover.rst Documentation: networking: correct spelling 2023-01-31 13:00:47 +01:00
netconsole.rst net: netconsole: add docs for appending netconsole user data 2024-02-09 10:23:45 +00:00
netdev-features.rst net: hsr: add offloading support 2021-02-11 13:24:44 -08:00
netdevices.rst net: remove stale mentions of dev_base_lock in comments 2024-02-14 11:20:13 +00:00
netfilter-sysctl.rst docs: networking: convert netfilter-sysctl.txt to ReST 2020-04-30 12:56:36 -07:00
netif-msg.rst docs: networking: convert netif-msg.txt to ReST 2020-04-30 12:56:36 -07:00
nexthop-group-resilient.rst Documentation: net: Document resilient next-hop groups 2021-03-29 13:51:38 -07:00
nf_conntrack-sysctl.rst netfilter: set default timeout to 3 secs for sctp shutdown send and recv state 2023-08-16 00:05:15 +02:00
nf_flowtable.rst docs: nf_flowtable: fix compilation and warnings 2021-03-25 17:42:02 -07:00
nfc.rst docs: networking: nfc: change to rst format 2019-11-23 11:00:19 -08:00
openvswitch.rst docs: networking: convert openvswitch.txt to ReST 2020-04-30 12:56:36 -07:00
operstates.rst docs: operstates: document IF_OPER_TESTING 2021-08-02 15:16:04 +01:00
packet_mmap.rst mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
page_pool.rst net: page_pool: expose page pool stats via netlink 2023-11-28 15:48:39 +01:00
phonet.rst Documentation: networking: correct spelling 2023-01-31 13:00:47 +01:00
phy.rst net: phy: Introduce PSGMII PHY interface mode 2023-08-14 08:12:53 +01:00
pktgen.rst pktgen: Introducing 'SHARED' flag for testing with non-shared skb 2023-09-28 16:25:14 +02:00
plip.rst docs: networking: convert PLIP.txt to ReST 2020-04-30 12:56:37 -07:00
ppp_generic.rst docs: update ppp_generic.rst to document new ioctls 2020-12-10 13:57:36 -08:00
proc_net_tcp.rst docs: networking: convert proc_net_tcp.txt to ReST 2020-04-30 12:56:37 -07:00
radiotap-headers.rst docs: networking: convert radiotap-headers.txt to ReST 2020-04-30 12:56:37 -07:00
rds.rst Doc: networking: Fix the title's Sphinx overline in rds.rst 2021-11-29 15:18:21 -07:00
regulatory.rst Documentation: networking: correct spelling 2023-01-31 13:00:47 +01:00
representors.rst docs: fix info about representor identification 2023-10-13 17:30:00 -07:00
rxrpc.rst rxrpc: Fix potential race in error handling in afs_make_call() 2023-04-22 15:16:39 +01:00
scaling.rst net: ethtool: add support for symmetric-xor RSS hash 2023-12-13 22:07:16 -08:00
sctp.rst docs: networking: convert sctp.txt to ReST 2020-04-30 12:56:38 -07:00
secid.rst docs: networking: convert secid.txt to ReST 2020-04-30 12:56:38 -07:00
seg6-sysctl.rst doc: move seg6_flowlabel to seg6-sysctl.rst 2021-04-14 13:13:15 -07:00
segmentation-offloads.rst networking: : fix typos in code comments 2019-05-20 20:24:34 -04:00
sfp-phylink.rst net: phylink: remove .validate() method 2023-10-17 17:51:53 -07:00
skbuff.rst skbuff: render the checksum comment to documentation 2022-05-10 17:48:37 -07:00
smc-sysctl.rst net/smc: add sysctl for max conns per lgr for SMC-R v2.1 2023-11-24 12:13:14 +00:00
snmp_counter.rst docs: automarkup: linkify git revs 2023-11-17 13:13:24 -07:00
statistics.rst docs: ethtool-netlink: document interface for MAC Merge layer 2023-01-23 12:44:18 +00:00
strparser.rst docs: networking: convert strparser.txt to ReST 2020-04-30 12:56:38 -07:00
switchdev.rst docs: net: add an explanation of VF (and other) Representors 2022-09-21 07:31:38 -07:00
sysfs-tagging.rst Documentation: networking: correct spelling 2023-01-31 13:00:47 +01:00
tc-actions-env-rules.rst docs: networking: convert tc-actions-env-rules.txt to ReST 2020-04-30 12:56:38 -07:00
tc-queue-filters.rst Documentation: networking: TC queue based filtering 2022-10-25 10:32:40 +02:00
tcp_ao.rst Documentation/tcp: Fix an obvious typo 2023-12-06 12:36:55 +01:00
tcp-thin.rst docs: networking: convert tcp-thin.txt to ReST 2020-04-30 12:56:38 -07:00
team.rst docs: networking: convert team.txt to ReST 2020-04-30 12:56:38 -07:00
timestamping.rst docs: networking: timestamping: mention MSG_EOR flag 2023-12-13 18:19:39 -08:00
tipc.rst Documentation: add more details in tipc.rst 2021-07-01 13:18:18 -07:00
tls-handshake.rst net/handshake: Enable the SNI extension to work properly 2023-05-24 22:05:24 -07:00
tls-offload-layers.svg Documentation: add TLS offload documentation 2019-05-22 12:18:20 -07:00
tls-offload-reorder-bad.svg Documentation: add TLS offload documentation 2019-05-22 12:18:20 -07:00
tls-offload-reorder-good.svg Documentation: add TLS offload documentation 2019-05-22 12:18:20 -07:00
tls-offload.rst net: Disable NETIF_F_HW_TLS_RX when RXCSUM is disabled 2021-01-19 15:58:05 -08:00
tls.rst tls: rx: add counter for NoPad violations 2022-07-11 19:48:33 -07:00
tproxy.rst docs: networking: convert tproxy.txt to ReST 2020-04-30 12:56:38 -07:00
tuntap.rst docs: networking: Replace strncpy() with strscpy() 2021-06-04 11:21:43 -06:00
udplite.rst docs: networking: convert udplite.txt to ReST 2020-05-01 12:24:40 -07:00
vrf.rst doc: Document unexpected tcp_l3mdev_accept=1 behavior 2021-08-23 11:53:24 +01:00
vxlan.rst docs: vxlan: add info about device features 2020-09-28 12:50:12 -07:00
x25-iface.rst docs: networking: fix x25-iface.rst heading & index order 2023-05-10 10:31:46 +01:00
x25.rst net: x25: Remove unimplemented X.25-over-LLC code stubs 2020-12-12 17:15:33 -08:00
xdp-rx-metadata.rst xdp: Add VLAN tag hint 2023-12-13 16:16:40 -08:00
xfrm_device.rst xfrm: generalize xdo_dev_state_update_curlft to allow statistics update 2024-02-05 16:45:49 -08:00
xfrm_proc.rst docs: networking: convert xfrm_proc.txt to ReST 2020-05-01 12:24:40 -07:00
xfrm_sync.rst docs: networking: convert xfrm_sync.txt to ReST 2020-05-01 12:24:41 -07:00
xfrm_sysctl.rst docs: networking: convert xfrm_sysctl.txt to ReST 2020-05-01 12:24:41 -07:00
xsk-tx-metadata.rst xsk: Add missing SPDX to AF_XDP TX metadata documentation 2023-12-05 15:08:50 +01:00