Commit Graph

70 Commits (f572286bf92c72c62776b26d69a24a8775ff2d39)

Author SHA1 Message Date
Brad Fitzpatrick 3d401c11fa all: use new Go 1.23 slices.Sorted more
Updates #12912

Change-Id: If1294e5bc7b5d3cf0067535ae10db75e8b988d8b
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 months ago
Maisem Ali af97e7a793 tailcfg,all: add/plumb Node.IsJailed
This adds a new bool that can be sent down from control
to do jailing on the client side. Previously this would
only be done from control by modifying the packet filter
we sent down to clients. This would result in a lot of
additional work/CPU on control, we could instead just
do this on the client. This has always been a TODO which
we keep putting off, might as well do it now.

Updates tailscale/corp#19623

Signed-off-by: Maisem Ali <maisem@tailscale.com>
7 months ago
Brad Fitzpatrick 7c1d6e35a5 all: use Go 1.22 range-over-int
Updates #11058

Change-Id: I35e7ef9b90e83cac04ca93fd964ad00ed5b48430
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
7 months ago
Brad Fitzpatrick 7b34154df2 all: deprecate Node.Capabilities (more), remove PeerChange.Capabilities [capver 89]
First we had Capabilities []string. Then
https://tailscale.com/blog/acl-grants (#4217) brought CapMap, a
superset of Capabilities. Except we never really finished the
transition inside the codebase to go all-in on CapMap. This does so.

Notably, this coverts Capabilities on the wire early to CapMap
internally so the code can only deal in CapMap, even against an old
control server.

In the process, this removes PeerChange.Capabilities support, which no
known control plane sent anyway. They can and should use
PeerChange.CapMap instead.

Updates #11508
Updates #4217

Change-Id: I872074e226b873f9a578d9603897b831d50b25d9
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
8 months ago
Brad Fitzpatrick b104688e04 ipn/ipnlocal, types/netmap: replace hasCapability with set lookup on NetworkMap
When node attributes were super rare, the O(n) slice scans looking for
node attributes was more acceptable. But now more code and more users
are using increasingly more node attributes. Time to make it a map.

Noticed while working on tailscale/corp#17879

Updates #cleanup

Change-Id: Ic17c80341f418421002fbceb47490729048756d2
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
8 months ago
Brad Fitzpatrick f45594d2c9 control/controlclient: free memory on iOS before full netmap work
Updates tailscale/corp#18514

Change-Id: I8d0330334b030ed8692b25549a0ee887ac6d7188
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
8 months ago
Adrian Dewhurst 2f7e7be2ea control/controlclient: do not alias peer CapMap
Updates #cleanup

Change-Id: I10fd5e04310cdd7894a3caa3045b86eb0a06b6a0
Signed-off-by: Adrian Dewhurst <adrian@tailscale.com>
8 months ago
Claire Wang 221de01745
control/controlclient: fix sending peer capmap changes (#11457)
Instead of just checking if a peer capmap is nil, compare the previous
state peer capmap with the new peer capmap.
Updates tailscale/corp#17516

Signed-off-by: Claire Wang <claire@tailscale.com>
8 months ago
Brad Fitzpatrick e1bd7488d0 all: remove LenIter, use Go 1.22 range-over-int instead
Updates #11058
Updates golang/go#65685

Change-Id: Ibb216b346e511d486271ab3d84e4546c521e4e22
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
9 months ago
Joe Tsai 94a4f701c2
all: use reflect.TypeFor now available in Go 1.22 (#11078)
Updates #cleanup

Signed-off-by: Joe Tsai <joetsai@digital-static.net>
10 months ago
Brad Fitzpatrick 2bd3c1474b util/cmpx: delete now that we're using Go 1.22
Updates #11058

Change-Id: I09dea8e86f03ec148b715efca339eab8b1f0f644
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
10 months ago
James 'zofrex' Sanderson 124dc10261
controlclient,tailcfg,types: expose MaxKeyDuration via localapi (#10401)
Updates tailscale/corp#16016

Signed-off-by: James Sanderson <jsanderson@tailscale.com>
11 months ago
Andrew Lytvynov 2716250ee8
all: cleanup unused code, part 2 (#10670)
And enable U1000 check in staticcheck.

Updates #cleanup

Signed-off-by: Andrew Lytvynov <awly@tailscale.com>
11 months ago
Brad Fitzpatrick fb829ea7f1 control/controlclient: support incremental packet filter updates [capver 81]
Updates #10299

Change-Id: I87e4235c668a1db7de7ef1abc743f0beecb86d3d
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
Brad Fitzpatrick 44c6909c92 control/controlclient: move watchdog out of mapSession
In prep for making mapSession's lifetime not be 1:1 with a single HTTP
response's lifetime, this moves the inactivity timer watchdog out of
mapSession and into the caller that owns the streaming HTTP response.

(This is admittedly closer to how it was prior to the mapSession type
existing, but that was before we connected some dots which were
impossible to even see before the mapSession type broke the code up.)

Updates #7175

Change-Id: Ia108dac84a4953db41cbd30e73b1de4a2a676c11
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
Brad Fitzpatrick c87d58063a control/controlclient: move lastPrintMap field from Direct to mapSession
It was a really a mutable field owned by mapSession that we didn't move
in earlier commits.

Once moved, it's then possible to de-func-ify the code and turn it into
a regular method rather than an installed optional hook.

Noticed while working to move map session lifetimes out of
Direct.sendMapRequest's single-HTTP-connection scope.

Updates #7175
Updates #cleanup

Change-Id: I6446b15793953d88d1cabf94b5943bb3ccac3ad9
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
Tom DNetto c08cf2a9c6 all: declare & plumb IPv6 masquerade address for peer
This PR plumbs through awareness of an IPv6 SNAT/masquerade address from the wire protocol
through to the low-level (tstun / wgengine). This PR is the first in two PRs for implementing
IPv6 NAT support to/from peers.

A subsequent PR will implement the data-plane changes to implement IPv6 NAT - this is just plumbing.

Signed-off-by: Tom DNetto <tom@tailscale.com>
Updates ENG-991
1 year ago
Maisem Ali 19a9d9037f tailcfg: add NodeCapMap
Like PeerCapMap, add a field to `tailcfg.Node` which provides
a map of Capability to raw JSON messages which are deferred to be
parsed later by the application code which cares about the specific
capabilities. This effectively allows us to prototype new behavior
without having to commit to a schema in tailcfg, and it also opens up
the possibilities to develop custom behavior in tsnet applications w/o
having to plumb through application specific data in the MapResponse.

Updates #4217

Signed-off-by: Maisem Ali <maisem@tailscale.com>
1 year ago
Brad Fitzpatrick 0d991249e1 types/netmap: remove NetworkMap.{Addresses,MachineStatus}
And convert all callers over to the methods that check SelfNode.

Now we don't have multiple ways to express things in tests (setting
fields on SelfNode vs NetworkMap, sometimes inconsistently) and don't
have multiple ways to check those two fields (often only checking one
or the other).

Updates #9443

Change-Id: I2d7ba1cf6556142d219fae2be6f484f528756e3c
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
James Tucker e7727db553 tailcfg: add DNS address list for IsWireGuardOnly nodes
Tailscale exit nodes provide DNS service over the peer API, however
IsWireGuardOnly nodes do not have a peer API, and instead need client
DNS parameters passed in their node description.

For Mullvad nodes this will contain the in network 10.64.0.1 address.

Updates #9377

Signed-off-by: James Tucker <james@tailscale.com>
1 year ago
Brad Fitzpatrick 9203916a4a control/controlknobs: move more controlknobs code from controlclient
Updates #cleanup

Change-Id: I2b8b6ac97589270f307bfb20e33674894ce873b5
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
Brad Fitzpatrick 3af051ea27 control/controlclient, types/netmap: start plumbing delta netmap updates
Currently only the top four most popular changes: endpoints, DERP
home, online, and LastSeen.

Updates #1909

Change-Id: I03152da176b2b95232b56acabfb55dcdfaa16b79
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
Brad Fitzpatrick 4e91cf20a8 control/controlknobs, all: add plumbed Knobs type, not global variables
Previously two tsnet nodes in the same process couldn't have disjoint
sets of controlknob settings from control as both would overwrite each
other's global variables.

This plumbs a new controlknobs.Knobs type around everywhere and hangs
the knobs sent by control on that instead.

Updates #9351

Change-Id: I75338646d36813ed971b4ffad6f9a8b41ec91560
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
Brad Fitzpatrick a79b1d23b8 control/controlclient: convert PeersChanged nodes to patches internally
So even if the server doesn't support sending patches (neither the
Tailscale control server nor Headscale yet do), this makes the client
convert a changed node to its diff so the diffs can be processed
individually in a follow-up change.

This lets us make progress on #1909 without adding a dependency on
finishing the server-side part, and also means other control servers
will get the same upcoming optimizations.

And add some clientmetrics while here.

Updates #1909

Change-Id: I9533bcb8bba5227e17389f0b10dff71f33ee54ec
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
Brad Fitzpatrick 947def7688 types/netmap: remove redundant Netmap.Hostinfo
It was in SelfNode.Hostinfo anyway. The redundant copy was just
costing us an allocation per netmap (a Hostinfo.Clone).

Updates #1909

Change-Id: Ifac568aa5f8054d9419828489442a0f4559bc099
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
Brad Fitzpatrick db017d3b12 control/controlclient: remove quadratic allocs in mapSession
The mapSession code was previously quadratic: N clients in a netmap
send updates proportional to N and then for each, we do N units of
work. This removes most of that "N units of work" per update. There's
still a netmap-sized slice allocation per update (that's #8963), but
that's it.

Bit more efficient now, especially with larger netmaps:

                                 │     before     │                after                │
                                 │     sec/op     │   sec/op     vs base                │
    MapSessionDelta/size_10-8       47.935µ ±  3%   1.232µ ± 2%  -97.43% (p=0.000 n=10)
    MapSessionDelta/size_100-8      79.950µ ±  3%   1.642µ ± 2%  -97.95% (p=0.000 n=10)
    MapSessionDelta/size_1000-8    355.747µ ± 10%   4.400µ ± 1%  -98.76% (p=0.000 n=10)
    MapSessionDelta/size_10000-8   3079.71µ ±  3%   27.89µ ± 3%  -99.09% (p=0.000 n=10)
    geomean                          254.6µ         3.969µ       -98.44%

                                 │     before     │                after                 │
                                 │      B/op      │     B/op      vs base                │
    MapSessionDelta/size_10-8        9.651Ki ± 0%   2.395Ki ± 0%  -75.19% (p=0.000 n=10)
    MapSessionDelta/size_100-8      83.097Ki ± 0%   3.192Ki ± 0%  -96.16% (p=0.000 n=10)
    MapSessionDelta/size_1000-8     800.25Ki ± 0%   10.32Ki ± 0%  -98.71% (p=0.000 n=10)
    MapSessionDelta/size_10000-8   7896.04Ki ± 0%   82.32Ki ± 0%  -98.96% (p=0.000 n=10)
    geomean                          266.8Ki        8.977Ki       -96.64%

                                 │    before     │               after                │
                                 │   allocs/op   │ allocs/op   vs base                │
    MapSessionDelta/size_10-8         72.00 ± 0%   20.00 ± 0%  -72.22% (p=0.000 n=10)
    MapSessionDelta/size_100-8       523.00 ± 0%   20.00 ± 0%  -96.18% (p=0.000 n=10)
    MapSessionDelta/size_1000-8     5024.00 ± 0%   20.00 ± 0%  -99.60% (p=0.000 n=10)
    MapSessionDelta/size_10000-8   50024.00 ± 0%   20.00 ± 0%  -99.96% (p=0.000 n=10)
    geomean                          1.754k        20.00       -98.86%

Updates #1909

Change-Id: I41ee29358a5521ed762216a76d4cc5b0d16e46ac
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
Brad Fitzpatrick cb4a61f951 control/controlclient: don't clone self node on each NetworkMap
Drop in the bucket, but have to start somewhere.

Real wins will come once this is done for peers.

                                 │     before     │                after                │
                                 │      B/op      │     B/op       vs base              │
    MapSessionDelta/size_10-8      10.213Ki ± ∞ ¹   9.650Ki ± ∞ ¹  -5.51% (p=0.008 n=5)
    MapSessionDelta/size_100-8      83.64Ki ± ∞ ¹   83.08Ki ± ∞ ¹  -0.67% (p=0.008 n=5)
    MapSessionDelta/size_1000-8     800.8Ki ± ∞ ¹   800.3Ki ± ∞ ¹  -0.07% (p=0.008 n=5)
    MapSessionDelta/size_10000-8    7.712Mi ± ∞ ¹   7.711Mi ± ∞ ¹  -0.01% (p=0.008 n=5)
    geomean                         271.1Ki         266.8Ki        -1.59%

                                 │    before    │               after                │
                                 │  allocs/op   │  allocs/op    vs base              │
    MapSessionDelta/size_10-8       73.00 ± ∞ ¹    72.00 ± ∞ ¹  -1.37% (p=0.008 n=5)
    MapSessionDelta/size_100-8      524.0 ± ∞ ¹    523.0 ± ∞ ¹  -0.19% (p=0.008 n=5)
    MapSessionDelta/size_1000-8    5.025k ± ∞ ¹   5.024k ± ∞ ¹  -0.02% (p=0.008 n=5)
    MapSessionDelta/size_10000-8   50.02k ± ∞ ¹   50.02k ± ∞ ¹  -0.00% (p=0.040 n=5)
    geomean                        1.761k         1.754k        -0.40%

Updates #1909

Change-Id: Ie19dea3371de251d64d4373dd00422f53c2675ea
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
Brad Fitzpatrick 84b94b3146 types/netmap, all: make NetworkMap.SelfNode a tailcfg.NodeView
Updates #1909

Change-Id: I8c470cbc147129a652c1d58eac9b790691b87606
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
Brad Fitzpatrick b5ff68a968 control/controlclient: flesh out mapSession to break up gigantic method
Now mapSession has a bunch more fields and methods, rather than being
just one massive func with a ton of local variables.

So far there are no major new optimizations, though. It should behave
the same as before.

This has been done with an eye towards testability (so tests can set
all the callback funcs as needed, or not, without a huge Direct client
or long-running HTTP requests), but this change doesn't add new tests
yet. That will follow in the changes which flesh out the NetmapUpdater
interface.

Updates #1909

Change-Id: Iad4e7442d5bbbe2614bd4b1dc4b02e27504898df
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
Brad Fitzpatrick 165f0116f1 types/netmap: move some mutations earlier, remove, document some fields
And optimize the Persist setting a bit, allocating later and only mutating
fields when there's been a Node change.

Updates #1909

Change-Id: Iaddfd9e88ef76e1d18e8d0a41926eb44d0955312
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
Brad Fitzpatrick 4511e7d64e ipn/ipnstate: add PeerStatus.AltSharerUserID, stop mangling Node.User
In b987b2ab18 (2021-01-12) when we introduced sharing we mapped
the sharer to the userid at a low layer, mostly to fix the display of
"tailscale status" and the client UIs, but also some tests.

The commit earlier today, 7dec09d169, removed the 2.5yo option
to let clients disable that automatic mapping, as clearly we were never
getting around to it.

This plumbs the Sharer UserID all the way to ipnstatus so the CLI
itself can choose to print out the Sharer's identity over the node's
original owner.

Then we stop mangling Node.User and let clients decide how they want
to render things.

To ease the migration for the Windows GUI (which currently operates on
tailcfg.Node via the NetMap from WatchIPNBus, instead of PeerStatus),
a new method Node.SharerOrUser is added to do the mapping of
Sharer-else-User.

Updates #1909
Updates tailscale/corp#1183

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
Brad Fitzpatrick 7dec09d169 control/controlclient: remove Opts.KeepSharerAndUserSplit
It was added 2.5 years ago in c1dabd9436 but was never used.
Clearly that migration didn't matter.

We can attempt this again later if/when this matters.

Meanwhile this simplifies the code and thus makes working on other
current efforts in these parts of the code easier.

Updates #1909

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
Brad Fitzpatrick 58a4fd43d8 types/netmap, all: use read-only tailcfg.NodeView in NetworkMap
Updates #8948

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
Brad Fitzpatrick af2e4909b6 all: remove some Debug fields, NetworkMap.Debug, Reconfig Debug arg
Updates #8923

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
Brad Fitzpatrick 25663b1307 tailcfg: remove most Debug fields, move bulk to nodeAttrs [capver 70]
Now a nodeAttr: ForceBackgroundSTUN, DERPRoute, TrimWGConfig,
DisableSubnetsIfPAC, DisableUPnP.

Kept support for, but also now a NodeAttr: RandomizeClientPort.

Removed: SetForceBackgroundSTUN, SetRandomizeClientPort (both never
used, sadly... never got around to them. But nodeAttrs are better
anyway), EnableSilentDisco (will be a nodeAttr later when that effort
resumes).

Updates #8923

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
1 year ago
Claire Wang a17c45fd6e
control: use tstime instead of time (#8595)
Updates #8587
Signed-off-by: Claire Wang <claire@tailscale.com>
1 year ago
Andrew Dunham 7aba0b0d78 net/netcheck, tailcfg: add DERPHomeParams and use it
This allows providing additional information to the client about how to
select a home DERP region, such as preferring a given DERP region over
all others.

Updates #8603

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: I7c4a270f31d8585112fab5408799ffba5b75266f
1 year ago
Will Norris 71029cea2d all: update copyright and license headers
This updates all source files to use a new standard header for copyright
and license declaration.  Notably, copyright no longer includes a date,
and we now use the standard SPDX-License-Identifier header.

This commit was done almost entirely mechanically with perl, and then
some minimal manual fixes.

Updates #6865

Signed-off-by: Will Norris <will@tailscale.com>
2 years ago
Brad Fitzpatrick 6edf357b96 all: start groundwork for using capver for localapi & peerapi
Updates #7015

Change-Id: I3d4c11b42a727a62eaac3262a879f29bb4ce82dd
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Andrew Dunham 3a018e51bb ipn/ipnlocal: move handling of expired nodes to LocalBackend
In order to be able to synthesize a new NetMap when a node expires, have
LocalBackend start a timer when receiving a new NetMap that fires
slightly after the next node expires. Additionally, move the logic that
updates expired nodes into LocalBackend so it runs on every netmap
(whether received from controlclient or self-triggered).

Updates #6932

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: I833390e16ad188983eac29eb34cc7574f555f2f3
2 years ago
Andrew Dunham 1e67947cfa control/controlclient, tailcfg: add Node.Expired field, set for expired nodes
Nodes that are expired, taking into account the time delta calculated
from MapResponse.ControlTime have the newly-added Expired boolean set.
For additional defense-in-depth, also replicate what control does and
clear the Endpoints and DERP fields, and additionally set the node key
to a bogus value.

Updates #6932

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: Ia2bd6b56064416feee28aef5699ca7090940662a
2 years ago
Brad Fitzpatrick eafbf8886d ipn/localapi: add localapi debug endpoints for packet filter/matches
For debugging #6423. This is easier than TS_DEBUG_MAP, as this means I
can pipe things into jq, etc.

Updates #6423

Change-Id: Ib3e7496b2eb3f47d4bed42e9b8045a441424b23c
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Joe Tsai 82f5f438e0
wgengine/wgcfg: plumb down audit log IDs (#5855)
The node and domain audit log IDs are provided in the map response,
but are ultimately going to be used in wgengine since
that's the layer that manages the tstun.Wrapper.

Do the plumbing work to get this field passed down the stack.

Signed-off-by: Joe Tsai <joetsai@digital-static.net>
2 years ago
Josh Soref d4811f11a0 all: fix spelling mistakes
Signed-off-by: Josh Soref <2119212+jsoref@users.noreply.github.com>
2 years ago
Tom DNetto e9b98dd2e1 control/controlclient,ipn/ipnlocal: wire tka enable/disable
Signed-off-by: Tom DNetto <tom@tailscale.com>
2 years ago
Brad Fitzpatrick 74674b110d envknob: support changing envknobs post-init
Updates #5114

Change-Id: Ia423fc7486e1b3f3180a26308278be0086fae49b
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Tom DNetto 18edd79421 control/controlclient,tailcfg: [capver 40] create KeySignature field in tailcfg.Node
We calve out a space to put the node-key signature (used on tailnets where network lock is enabled).

Signed-off-by: Tom DNetto <tom@tailscale.com>
2 years ago
Brad Fitzpatrick 4ee64681ad tailcfg, control/controlclient: make Debug settings sticky in a map session [capver 37]
Fixes #4843

Change-Id: I3accfd91be474ac745cb47f5d6e866c37d5c5d2d
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick 7c7e23d87a control/controlclient, tailcfg: add 6 more patchable Node fields [capver 36]
Change-Id: Iae997a9a98a5dd841bc41fa91227d5a7dd476a25
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago
Brad Fitzpatrick a12aad6b47 all: convert more code to use net/netip directly
perl -i -npe 's,netaddr.IPPrefixFrom,netip.PrefixFrom,' $(git grep -l -F netaddr.)
    perl -i -npe 's,netaddr.IPPortFrom,netip.AddrPortFrom,' $(git grep -l -F netaddr. )
    perl -i -npe 's,netaddr.IPPrefix,netip.Prefix,g' $(git grep -l -F netaddr. )
    perl -i -npe 's,netaddr.IPPort,netip.AddrPort,g' $(git grep -l -F netaddr. )
    perl -i -npe 's,netaddr.IP\b,netip.Addr,g' $(git grep -l -F netaddr. )
    perl -i -npe 's,netaddr.IPv6Raw\b,netip.AddrFrom16,g' $(git grep -l -F netaddr. )
    goimports -w .

Then delete some stuff from the net/netaddr shim package which is no
longer neeed.

Updates #5162

Change-Id: Ia7a86893fe21c7e3ee1ec823e8aba288d4566cd8
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2 years ago