A code-quality pass over policy, configuration and the status API.
The twenty TCP gauges were spelled out in the struct, the
constructor, the removal, the sampler in the web crate and the status
view; one macro names each once with its help text, `PeerTcp::set`
fills them from a connection, and the view is a `From`. Every metric
and the list that forces them at start come from one declaration,
with a test that every declared family is registered. The two
revalidators, for next hops and for RPKI, share the task body that
scans the table off the sessions' threads and fans the findings out
to every session; the RPKI scan judges a route with the same `Checks`
the import path uses. Which peer a query names is one rule for the
received, rejected and TCP endpoints, so `/api/tcp` takes a name or an
address like the others. The config parser says proto3's "zero is
unset" in three helpers instead of a dozen shapes, and `parse_peer`
is three named parts shorter. The policy's test-only next-hop flag is
named for what it does, `accept_own_host_next_hop`; the "listed, or
else ours" prefix rule and the mark-then-prefer step each exist once.
The status page derives its spanning rows from the table's header,
shares one key-value grid and one detail-row rule, and defines its
helpers before their use. The web crate no longer re-exports views
nothing uses, and the TCP endpoint sits above the test module.
Testing: the TCP view's arithmetic (a share of no busy time is zero,
not NaN), the peer-naming rule, the RPKI scan finding only what a
change can have made invalid, and `/api/tcp` by address, by name and
for an unknown peer. The server and web tests, the HTTP, roles, RPKI
and import-policy integration tests, the docs build and every lab
phase pass.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
A router feeding a collector every path (all_paths) was 4.8 GB resident
with a table that should take a third of that. A heap profile of the
daemon in the Linux VM, with four full tables and such a collector,
showed where it went: the exporter kept, for every route it had
advertised, the route's outgoing form, the parsed attribute list it was
dressed with, through an `Arc<Dressed>` in the per-route record. One
such form lived for every distinct attribute set advertised, about a
kilobyte each, for the life of the session, on top of the exporter's
cache of 262,144 of them. The record needs only to tell whether a route
changed, and the table's own attribute set, which is in memory anyway,
tells it that: the outgoing form is a function of the set, the peer the
route came from and the policy.
This change:
* `Sent` holds an `Arc<AttrSet>` instead of an `Arc<Dressed>`, and a
route is sent again when its set differs. `Verdict::All` carries both
while a flush is on.
* `DRESSED_KEPT` goes from 262,144 to 65,536: a kilobyte a set, so 64 MB
rather than 256 MB a session at most; what a flush is sending holds
its own.
* The status page's header shows the daemon's memory as jemalloc
accounts for it (allocated and resident), `/api/status` has the six
figures (`memory`: allocated, active, metadata, resident, mapped,
retained), and `bgp_memory_bytes{kind}` exports them. jemalloc is built
with statistics for this, and `bgp-web` reads them through
`tikv-jemalloc-ctl`.
* `scripts/profile/full-table.sh` gains `COLLECTOR=1`, a collector
session over IPv6 that takes both families with ADD-PATH, and `HEAP=1`,
which builds the daemon with jemalloc's heap profiler (the new
`heap-profiling` feature of the daemon crate, not for production) and
turns the profile into a flame graph with jeprof; and it reports
memory with the table in and again 30 s later. The feeder
(`crates/bench/examples/feed.rs`) plays the collector with
`FEED_COLLECTOR=1`.
Measured in the VM, four peers' full tables and a collector sent every
path (4.9 million routes advertised): 1,723 MiB resident before, 1,286
MiB after, with jemalloc's allocated figure from 1,500 MiB to 946 MiB.
Without the collector the same tables take 630 MiB, so the collector's
bookkeeping is now about 50 bytes a route advertised. Of the resident
figure, some 400 MiB was pages jemalloc had freed and not yet returned:
it returns them on allocator activity only, and a router that has its
tables in allocates little. jemalloc is now built with its background
thread on (the `background_threads` feature), which returns them on
time: 1,020 MiB resident 30 s after the load, against 1,286 MiB without
it.
Documentation: `memory` in the HTTP API reference, `bgp_memory_bytes`
in the metrics reference and the monitoring guide, the script's new
settings in the testing guide.
Testing: the ADD-PATH integration tests pass, including the collector
ones; the heap profile and the figures above are from
`PEERS=4 COLLECTOR=1 HEAP=1 scripts/profile/full-table.sh` in the VM.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
The kernel's view of a session's TCP connection, which the status page
shows on request since the last change, could not be looked at after
the fact: a feed that crawled overnight left no record of whether the
peer's window or our own side held it up.
This change samples it at every scrape of `/metricz`: for each
established session, one `NETLINK_SOCK_DIAG` round trip, and twenty
gauges labelled by peer, `bgp_peer_tcp_*`: smoothed, least and variance
of the round-trip time; the congestion window and segment size; the
peer's receive window and ours; the send queue, the part of it not yet
sent, the receive queue and the segments in flight; retransmitted and
lost segments; the busy time and the time held up by the peer's window
and by our send buffer, cumulative, so that their rates give the share
of time a session is held up; octets sent and received; and the
delivery and pacing rates. A session the kernel has no connection for
loses its series, as does one that ends.
`SessionHandle::metric_label` is the one place a peer's metric label is
made (its name, or its address), used by the advertiser's gauge and here.
Documentation: the metrics reference lists them; the monitoring guide
gives the query for the share of time a session is held up by the
neighbor's receive window, which is the question the overnight feed
raised.
Testing: a daemon in the Linux VM with one session shows the series and
drops them when the session ends; the lab's basics phase checks the
scrape for the FRR session's round-trip time; the workspace tests pass.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
When a session advertised a full table to a route collector at two
thousand routes a second, nothing on the status page said whether the
daemon or the peer set that pace. The answer is in the kernel: the
peer's receive window, the queues, and how long the connection was held
up by the window or by the send buffer, which `ss -ti` shows.
This change asks the kernel the same way `ss` does, over the socket
diagnostics netlink family (`NETLINK_SOCK_DIAG`, `SOCK_DIAG_BY_FAMILY`
with the connection's addresses and ports), and reads `tcp_info` and
the congestion control name from the answer. No external program is
run and no unsafe code is needed: the request and the answer are byte
layouts of the kernel's ABI, read field by field, with fields an older
kernel does not send left at zero. A socket on a link-local address is
found by its interface, which the request names.
* `bgp_fib::sockdiag`: the request, the parser, `TcpConnection`, and
`tcp_connection(local, peer)`; `Ok(None)` where there is no such
connection or the system is not Linux.
* `GET /api/tcp?peer=ADDRESS` in the HTTP API: the connection of the
session with that peer, with times in milliseconds, the two windows
named by what they allow, and the held-up times also as shares of the
busy time.
* The status page: a "tcp" link on each established session, which
expands a row below it with the figures, re-asked on every refresh
while open. The group rows' span is corrected for the "sent" column.
Also on the status page: the attributes of a received route that have
no column of their own were badges with their value in a tooltip, which
is hard to read. Clicking the attrs cell now expands a row under the
route with every attribute by its name (ORIGIN, AS_PATH, NEXT_HOP, MED,
LOCAL_PREF, COMMUNITIES, LARGE_COMMUNITIES, AGGREGATOR and the rest),
the path identifier, the selection rank and the RPKI and ASPA states;
the badges stay. Both expansions use the terms of `ss` and the RFCs
rather than sentences.
Documentation: the endpoint in the HTTP API reference, and the link and
the expansion in the monitoring guide.
Testing: unit tests of the request and of the parser on a reply built
field by field, and of a "no such socket" and a refused answer; a
Linux-only test that asks the kernel about a loopback connection of the
test's own and about one that does not exist; the lab's basics phase
checks the endpoint for the FRR session; the page was checked by hand
against the daemon in the Linux VM.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Before this change, a session on which ADD-PATH (RFC 7911) was
negotiated in the sending direction was sent path identifiers, but only
the best route for each prefix. A route collector such as bgp.tools
wants every route a router has accepted, from every neighbor, and from
one session: without this the collector saw one path per prefix, nearly
always the same neighbor's.
This change adds `all_paths` to the export policy. On a session with it,
and ADD-PATH send negotiated for a family, every accepted route for a
prefix of that family is advertised, each with a path identifier of its
own; for a family without ADD-PATH send the best route goes as before.
`all_paths` needs `learned_routes` (a configuration error otherwise) and
the peer's `add_path` to offer sending. The export policy, the role
rules, the well-known communities and the export limits apply to every
route alike, and the export limits count every route.
Implementation, in the advertiser:
* An exporter with `all_paths` follows the table's journal of all routes
(`RibTable::reader_of_all_routes`, until now unused) instead of the
best-route journal, and is given all the routes of a prefix whenever
one of them changes (`News::Routes`).
* What the peer holds is `Announced`: the set of prefixes for a
best-route session, as before; or for an all-paths session, for each
prefix the routes announced, keyed by the peer they came from and that
peer's own identifier, with the identifier they went out with and the
form they went out in. A route keeps its identifier for as long as it
is announced, goes out again only if it changed, and is withdrawn by
its identifier; a new route gets the lowest identifier not in use for
the prefix, from 1.
* Verdicts carry either kind (`Verdict::Best`, `Verdict::All`), and a
reset of the table puts what was announced in doubt until heard of
again, as before, with the same identifiers kept across the reset.
* The record for an all-paths session is about 50 bytes a route, some
tens of megabytes for a full table from several neighbors; the
best-route bookkeeping is unchanged in size.
Also, so that a collector session can be watched: the number of routes
advertised to each peer and not withdrawn since, every route counted
where several are sent for a prefix. The exporter keeps it in the
session's counters after every change; it is `advertised_routes` in
`/api/peers`, the "sent" column of the status page's neighbor table,
and the gauge `bgp_peer_advertised_routes{peer}`.
Documentation: a "Feeding a Route Collector" section in the guide to
passing routes on, with the configuration for a collector; `all_paths`
in the configuration reference; the ADD-PATH sections of the neighbor
guide and the standards reference; the limitation that was removed;
the new field, column and metric in the HTTP API, monitoring and
metrics references.
Testing: an integration test with two feeders and a collector that
negotiated ADD-PATH receive, which checks the two routes with their
identifiers, the withdrawal of one by its identifier, a changed route
keeping its identifier and a new route taking the free one; a
configuration test for `all_paths` without `learned_routes`; a new
`collector` phase of the interoperability lab in which FRR, as a route
collector, is told both of BIRD's routes for a prefix from BIRD's two
sessions and holds them apart, and loses one when its session is
disabled, with the advertised count checked at each step. The workspace tests, the kernel tests and every lab phase pass.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
A row's routes are in a vector that grew by one route at a time, so with
four peers sending full tables every row's vector was reallocated three
times as their routes arrived, and the reallocations were 7% of the
daemon's CPU time in a profile of a four-peer load.
This change has the first growth of a row take it to as many routes as
the table has peers, at most 8 (`FIRST_ROOM`), since a prefix that one
full table has, the others nearly always have too; after that it grows
by a quarter as before. A table with one peer never grows a row and is
unchanged. A route server's clients do not all announce every prefix,
hence the cap: a row of a prefix that fewer peers announce has at most
seven spare slots of 16 bytes.
Measured in the Linux VM with four peers sending the synthetic table of
1.23 million prefixes: the kernel is in step 1.9 s after the first route
instead of 2.2 s, the daemon's CPU time over the load is 5% lower, and
it is 604 MiB resident instead of about 630, since there are no
reallocation leftovers. With one peer nothing changes. Memory per route
in the benchmarks, allocations counted: 77 bytes before and after with
the synthetic table from four peers; 64 before and 65 after with the
RIPE RIS dump's eight largest peers, whose load went from 2.8 s to
1.8 s on one thread, the allocation counting making every reallocation
dearer than it is in the daemon.
Also tried and not adopted, with the new `JEMALLOC_CONF` setting of the
profiling script: transparent huge pages for the allocator
(`thp:always,metadata_thp:always`). Over three pairs of runs with one
peer the table arrived in 0.66, 1.17 and 0.70 s with them against 0.87,
0.75 and 0.87 s without, the CPU time was within the noise, and the
daemon was 60 to 100 MiB larger. An arena for the routes would not help
either: jemalloc's size classes already give rows exact 16, 32, 48 and
64 byte allocations, and the cost was the number of reallocations, not
the allocator.
Testing: the table tests, including the one that grows a row past
65,535 routes, pass; the kernel tests and the interoperability lab pass.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
The routing table's shards started empty and grew as routes came in,
each growth moving every row of the shard into a table twice the size.
In a profile of the daemon taking in a full table, the growth showed as
up to a seventh of the session's time, and the daemon's resident memory
had the old and the new table of each shard side by side for a moment.
This change adds `RibTable::expect_prefixes`, which reserves room for
that many prefixes spread over the shards, and has the server call it at
startup with the largest `expected_routes` among the configured peers:
the prefixes of several full tables are mostly the same ones. Without
`expected_routes` nothing changes. The `full_table` benchmark does the
same unless `BENCH_PRESIZE=0`.
Measured, the saving in time is within the run-to-run noise: in the
Linux VM one peer's table is in the routing table in 0.81 s instead of
0.89 s, and the kernel is in step at about the same time as before;
three pairs of runs of the benchmark on a Mac average 0.33 s against
0.35 s. The profile's attribution to the growth was mostly sampling skid.
The memory saving is real: 442 MiB resident with one peer's table in
instead of 483 MiB, and 626 MiB instead of 632 MiB with four.
Also: the profiling script printed nothing for the kernel's change
counts because it asked `/metrics` for them; the endpoint is `/metricz`.
With that fixed, a four-peer load shows 1.25 million installs for 1.23
million prefixes: the journal already gives the kernel task only the
latest change of a prefix when it lags, so no further coalescing of
installs is called for.
Documentation: `expected_routes` in the configuration reference, the
neighbor guide and the proto comment say that the table is sized by it;
the testing guide's VM results are brought up to date.
Testing: a table test checks that the room is there and is kept; the
workspace tests pass.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Before this change there was no way to see where the daemon's CPU time
goes while it receives a full Internet routing table: the benchmarks in
crates/bench time the routing table in-process, without the sessions,
the policy, the kernel task or the production allocator. Profiling the
daemon itself showed that a third of its CPU time during a full-table
load went into `Plan::blackholes()`, which walked every installed route
to count the blackhole ones each time the kernel task published its
status, after every batch of changes; with 1.2 million routes
installed that was 3.9 seconds from the first route to a synced kernel
instead of 2.0.
This change:
* Keeps counts of blackhole routes and of routes kept unconfirmed from
an earlier run in `Plan`, in step with the map through `Plan::put`
and `Plan::take`, so that `Plan::blackholes()` and `Plan::kept()`
cost nothing. `kept()` had the same scan; it ran only while routes of
an earlier run were being kept, which is exactly during a full-table
load after a restart.
* Adds `scripts/profile/full-table.sh`, which builds the daemon with the
new `profiling` Cargo profile (release with line tables) and frame
pointers, runs it in a network namespace joined by a veth pair to a
second namespace, feeds it the synthetic table from there as one or
more neighbors, samples it with `perf`, and writes a flame graph
(inferno), flat profiles by self and inclusive time, the time until
the routes are in the table and in the kernel, and the daemon's
resident memory. `PEERS`, `KERNEL`, `SCALE_DOWN`, `HOLD_SECS`, `FREQ`
and `OUT` control it. From macOS it runs in the Linux VM through
scripts/linux-vm.sh.
* Adds the load generator `crates/bench/examples/feed.rs`: it connects
from the peers' addresses, completes the handshakes, writes each
neighbor's table, drains what the daemon sends back and holds the
sessions open with KEEPALIVEs. `TestPeer::into_stream` gives it the
connection after the handshake.
* Updates the testing guide: the current `full_table` numbers, a
"Profiling" section, and the daemon's numbers in the VM.
Measured in the Linux VM (8 vCPUs) with the synthetic table of 1.23
million prefixes: one neighbor's table is in the routing table after
0.7 s and in the kernel after 2.0 s (before: 3.9 s); four neighbors'
4.9 million routes are in the table after 1.1 s and the kernel is
synced after 3.0 s; 520 MB resident with one table, 680 MB with four.
Without the kernel one session takes in 2.0 million routes per second
on one core. A profile also attributed 14% of the session's time to
`Journal::tidy`; inlining its early return changed nothing in an A/B
run of the benchmark, so that was a sampling artefact and is left as it
is.
Testing: a unit test checks the counts against a scan of the entries
through adopt, best, reset, synced, release, withdrawal, refusal and
clear; the kernel test suite and the workspace tests pass; the script
was run with one and four neighbors, with and without the kernel.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Before this change, a route carrying the BLACKHOLE community (65535:666,
RFC 7999) from an EBGP neighbor was always rejected with the reason
"blackhole request", and nothing discarded traffic. A customer under a
denial-of-service attack had no way to ask this router to drop traffic
to an address.
This change adds `accept_blackholes` to the import policy. When it is
set, a route with the BLACKHOLE community is accepted if:
* its prefix is a single address, a /32 or a /128 (otherwise it is
rejected with the new reason "blackhole for more than one address");
the `max_ipv4_prefix_length` and `max_ipv6_prefix_length` limits do
not apply, as RFC 7999 section 3.2 recommends;
* the address is inside a prefix the neighbor may announce, if
`prefixes` is configured, regardless of the entry's `max_length`
(new `PrefixSet::covers`); without a prefix list, an address inside
the local AS's own prefixes is rejected as before ("prefix is our
own");
* the AS path, origin and RPKI checks that apply to every route pass.
The next hop of an accepted blackhole route is not checked for
third-party addresses and is not resolved, because traffic is never
forwarded to it. The route takes part in best path selection as usual;
a host route is normally the active route for its address.
The kernel task installs the active route as a kernel blackhole route
(`RTN_BLACKHOLE`, shown by `ip route` as `blackhole PREFIX proto bgp`).
Blackhole routes left by an earlier run are adopted at startup like
other routes of ours. The route is advertised to other neighbors as the
export policy and export limits permit, with the community intact, so a
provider that honors BLACKHOLE can discard the traffic upstream.
Implementation:
* `plan::Target` becomes an enum: `Via { gateway, interface }` or
`Discard`. `plan::resolve` takes a `blackhole` flag and returns
`Discard` for such routes without looking at the next hop (the
own-network check still applies). No nexthop object is made for a
discard target.
* `AttrSet::is_blackhole` reads the community off the stored attribute
bytes, like `next_hop` and `as_path`, so the kernel task, the
revalidator and the RPKI revalidation can ask it of every route.
* `ImportPolicy::is_blackhole_request` and `check_blackhole_prefix`
carry the import side; the import flow (`routes.rs`) computes once per
UPDATE whether its routes are an accepted blackhole request and skips
the next hop checks for them.
* `Status::blackholes` and the `blackholes` field of `/api/kernel` count
the installed blackhole routes; the status page shows the count next
to the installed routes.
Not covered: a prefix this router originates with the BLACKHOLE
community is advertised but not installed as a blackhole route. The
documentation says to add a kernel blackhole route by hand for that
case.
Documentation: the "Blackhole Routes" section of the import policy
guide replaces "Blackhole Requests", the kernel guide gains a "Blackhole
Routes" section, the configuration reference describes
`accept_blackholes`, the HTTP API reference describes `blackholes`, and
the RFC 7999 rows of the standards reference are updated.
Testing: unit tests for the attribute check, the prefix checks and the
plan; integration tests that a blackhole request is refused by default
and, with `accept_blackholes`, taken for one address inside the peer's
space and refused otherwise, with the recorded reasons; a kernel test
that a blackhole request becomes a kernel blackhole route whatever its
next hop, is removed on withdrawal and is adopted after a restart. The
existing kernel tests, the interoperability lab and the workspace tests
pass.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Before this change, Ferrix only installed a route if its BGP next hop was
directly connected: an address in the subnet of an interface that is up.
A route with any other next hop was held at import and never installed.
This made routes from iBGP neighbors unusable unless the neighbor set
itself as the next hop, and it is why the route reflector rewrites the
next hop on every reflected route.
Ferrix now resolves a next hop that is not directly connected through the
kernel's own routes, as other BGP implementations do:
* The route is looked up in one kernel table, the "resolution table"
(`kernel { resolution_table: N }`, default 254 = main). The longest
prefix that contains the next hop wins; of several routes for that
prefix, the one with the lowest metric.
* Because the Linux kernel does not resolve gateways recursively, the BGP
route is installed with the gateway and interface of the kernel route
that covers the next hop. A kernel route without a gateway (a route
onto a point-to-point or tunnel interface) makes the next hop itself
the gateway on that interface. A kernel route that names a nexthop
object is resolved through the object.
* Routes with protocol `bgp` never resolve a next hop, whether Ferrix's
own or another daemon's. A next hop that is reachable only through a
BGP route depends on another BGP next hop, and such chains are not
predictable.
* The default route does not resolve a next hop unless
`kernel { resolve_via_default_route: true }` is set. On a router the
default route points at a transit provider, and a next hop that is
reachable only through it is not usable.
* Blackhole, unreachable and prohibit routes make the next hop
unresolvable, as does a route whose interface is down.
The same resolution is used by the import policy and the revalidator, so
a route whose next hop cannot be resolved is still held rather than
selected (RFC 4271 section 9.1.2.1), and is taken when a kernel route
makes its next hop resolvable.
Implementation:
* `bgp_fib::routes::KernelRoutes` holds the routes of the resolution
table and answers longest-prefix lookups.
* `bgp_fib::topology::Topology` bundles the interfaces, the kernel routes
and the kernel's nexthop objects into one value. The kernel task
publishes it through `Fib::topology()` (formerly `Fib::interfaces()`),
and `plan::resolve` takes it in place of `Interfaces`.
* The kernel task learns the resolution table with a dump of that table
alone, using NETLINK_GET_STRICT_CHK (Linux 4.20 and later; older
kernels get a dump of every table, filtered in user space). It asks
again, debounced, whenever a dedicated netlink socket that is a member
of the route multicast groups receives anything. That socket is given a
64 KiB receive buffer on purpose: the kernel reports Ferrix's own route
installs on it too, up to a million at a time, and an ENOBUFS overflow
is treated as the same hint as a message. Its contents are never
parsed. An earlier attempt to receive route notifications on the
socket that writes routes failed, because the kernel only excludes the
requesting socket from a notification when NLM_F_ECHO was requested.
* `Unresolved::NotConnected` is replaced by `NoRoute`, `OnlyDefault` and
`Discarded`, which appear as the reasons in `/api/kernel` and on the
status page.
Configuration: two new `kernel` fields, `resolution_table` and
`resolve_via_default_route`, documented in the configuration reference
and in the kernel guide, whose "Next Hop Resolution" section is rewritten.
Existing configurations behave as before except that routes with far
next hops may now be installed where a static or connected route covers
the next hop.
Testing: unit tests for `KernelRoutes`, `Topology` and resolution
through static, tunnel, nexthop-object, blackhole and default routes; a
kernel test (`a_far_next_hop_goes_the_way_the_kernels_routes_say`) that
checks the installed routes follow static, tunnel and nexthop-object
routes as they are added, replaced and removed; the existing kernel
tests, the interoperability lab with FRR and BIRD, and the workspace
tests, all passing. Installing 200,000 routes still runs at about
186,000 routes per second.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Of <stem>-v6 and <stem>-v4, the IPv6 session is listed first and carries
the name in full; IPv4 is under it. The same order in the lookup's list of
peers.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
The attention strip's names lead to the peer's row, which lights up for a
moment. The IPv4 and IPv6 sessions of one neighbour (NAME-v4, NAME-v6) are
listed together, joined down the side, the name said once in full. A route
count that moved by more than 2% between refreshes carries ▲ or ▼ for two
minutes; a row whose state or count changed while the tab was in the
background carries ● until it is clicked. A compact mode drops the next
hop and session columns, and is remembered by the browser. Colours are
variables, with a second set for prefers-color-scheme: dark.
A new per-peer `expected_routes` says about how many routes a peer sends
when all is well. The daemon only passes it to the API; the page lists an
established peer with under half of it as needing attention, a minute
after the session came up, with the expected count beside the actual one.
An established session with next to no routes looked, until now, exactly
like one that was fine.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
The documentation sources are Zola Markdown: front matter between +++
lines, shortcodes that insert the example configurations, and @/ internal
links. A code forge shows all three unrendered, which the README used to
deny. A docs/README.md now explains each, and the README points to it.
"Configuring BGP Neighbors" becomes "BGP Neighbors", as the other feature
pages are titled; "When a Neighbor Restarts" becomes "Neighbor Restart", a
noun phrase as the style guide asks.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Received routes are listed from the best down: the RIB gains ranked_routes,
which runs selection again without the winners, so the second route is the
one that would be installed were the best withdrawn. The API gives each
route its rank, and the page shows it as a numbered badge after the star.
The lookup box moves to the received-routes table, which is what it filters,
and takes an AS number: a new `origin` query parameter finds every route
whose path ends in that AS, with an empty path counting as the local AS.
Long cells are clamped to a few lines with a control to open them, and an
AS repeated along a path (prepending) is shown once with a ×N badge. Peer
names are bold and dark, not underlined links, so a row can be found by
its name among the addresses and numbers.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
The page opened with every session in bold green, the normal state, and
the brightest numbers on it were the rejection counts, which RPKI doing
its job produces by the thousand. The two sessions that were actually
down were in the same red, thirty rows down. Now:
- A status line at the top says what needs attention, by name and with
the reason: sessions down, peers restarting, the kernel behind or
refusing routes, RPKI data missing or about to expire. When nothing
does, it says so. A second line gives the normal state in grey.
- Colour means one thing each. Red: failed, needs a hand. Amber:
degraded, worth watching. Green, set small: a system doing its job.
Grey: inactive and expected. Normal is black; "Established" is no
longer green, and a rejection count no longer red.
- Peers that need attention come first, then the others grouped by what
they are to us, with a "problems only" switch. Numbers are right
aligned with thousands separators; the established time and uptime
are one cell; the session's properties are glyphs (v4, v6, GR, ENH,
AP, 2B) with the meaning as a tooltip, as are the roles.
- Received routes: the best route leads, marked ★; attributes without a
column are glyphs (OTC, AA, AGG, AS4, OID, CL); validity is ✓ ✗ –.
- Rejected routes: those alike (same prefix, reason and path) are one
row with a count and the last time; each peer's reasons are a bar.
- Communities with a configured name (community_names, new) are badges
with that name, the number as the tooltip: "comrack", "SwissIX",
"interconnection 2011" rather than 210036:100:2 and so on. A name for
a pattern shows the open part after it. The daemon does nothing with
the names but pass them to the page.
- One lookup box at the top, which takes a peer's name too; a peer's
name anywhere on the page leads to its routes; table headers and the
status line stay in view while scrolling.
- The host name comes from gethostname(2), not from running `hostname`,
which a static binary on a bare machine could not find: comrack said
"unknown host".
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
- scripts/in-namespace.sh set CARGO_TARGET_DIR to the empty string when
it was unset, which cargo refuses, and dropped RUSTFLAGS, so the run
in the namespace rebuilt what kernel-tests.sh had just built. Each is
passed on only where set.
- The README's list of unsupported features still had route reflection
and graceful restart, both of which exist; the command-line reference
lacked SIGUSR1 and exit status 75; the HTTP API reference did not say
what errors look like.
- The event stream said "missed 0 events" for the best-routes stream,
which does not count what it missed; it leaves the count out now.
- CI lints bgp-bench with its count-memory feature, which nothing built.
- bgp-bench had two unused dev-dependencies; bgp-integration-tests had
three dependencies that only its tests and examples use.
- install.sh updates apt before installing; two-routers.sh loses an
unused variable; small things in the web crate.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Readability, no change in behaviour, but for one log line:
- The routes a peer holds from us were counted twice over, differently,
in the exporter: once per learned-route batch and once per originated
route. Learned::held_by_peer counts the learned ones in one place, and
ExportLimits::exceeded_by returns the limit that was passed instead of a
bool, so that ending the session no longer has to dig it out again with
a default that could not happen.
- The two hold-downs for a limit passed, ours or the peer's, were two
near-identical blocks; they are one match.
- How a session ended is put into words in one place
(SessionEnd::reason), for the dialer's backoff and the passive peer's
state alike.
- parse_export_limits parses one block; what a missing block means (no
limits at the top, the top's limits for a peer) is said where it
differs, instead of Option in and Option out.
- The startup warnings about export limits are a function of their own,
and the peers without limits are named in one line rather than one
line each: a router with eighty sessions does not need eighty warnings.
The warning about a peer without a role is gone: the configuration now
refuses one.
- Hex formatting of attribute octets is one function; the text for an
unknown attribute is built in three plain steps.
- The exporter's test fixture returns a named struct, not a tuple.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
A session could only be configured for a peer we would then dial, every
few seconds to two minutes, for as long as it was not up. A new peer
whose side was not ready yet filled the log with failed attempts, and a
peer that opens its sessions itself was dialled for nothing.
A peer with `passive: true` is not dialled. A connection from its address
is taken as for any configured peer, and the session comes up with all
that is configured for it: role, import policy, export limits,
hold-downs. Until then the status page and /api/peers show it as
`Passive`, waiting for the peer to connect; after a session, with how
that session ended, which nothing else would say since nobody dials it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
What other networks were told of rested on one thing: the Only to
Customer mark that routes from providers, peers and route servers get as
they come in. A route without it, from a session without a role or by a
mistake anywhere along the way, went to every peer, from every router of
ours, and nothing of ours stood in the way.
export_limits are a second check, independent of the roles, the marks
and the export policy. For peers above or beside us (PROVIDER, PEER,
ROUTE_SERVER, and any in another AS without a role):
- prefixes: only routes for these go out, learned or our own. With our
and our customers' space listed, a leak of anyone else's routes goes
nowhere above us.
- max_prefixes: if more routes were to go out than this, none of them
does. The session ends with a Cease / Administrative Shutdown whose
Shutdown Communication says why (RFC 9003), and the peer is held down
for its import.hold_down_seconds, so that it is told nothing rather
than too much. The whole table is counted before any of it is sent.
They are set at the top and hold for every such peer that has none of its
own; unlike `export`, a peer's own export policy does not drop them. A
peer's own export_limits take their place, and an empty one lifts them.
Customers, route server clients and our own routers are not limited.
A configuration in which learned routes are passed on and a peer in
another AS has no role is now refused, as is accept_unconfigured_peers
with learned routes: without a role, a peer's routes go to everyone and
it is told of everything. This used to be a warning.
At startup, a warning for each peer the limits apply to that has none,
and for each originated route the limits leave out. A metric,
bgp_export_limit_exceeded_total, counts the sessions ended for it.
The interop lab has a phase in which a customer leaks: a route outside
its space never reaches BIRD, and when more were to go than the limit,
BIRD's session ends and its log has our reason.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The kernel section was one run-on line of interfaces and addresses. It is
now a small table of the installation state, and a table of interfaces
with their IPv4, IPv6 and link-local addresses one per line; ports that
are down and have no addresses share one line at the bottom.
Communities ran together into one block that wrapped anywhere. Each AS's
communities are now a line of their own, kept whole so that they copy,
with a hanging indent where a line wraps; pointing at a line names the AS.
Where control communities are on (now in /api/status), those of ours that
ask for something say what as a tooltip.
A rejected route's details were a fold-out that repeated the summary and
then dumped the decoded attributes as JSON. Rejected routes now have the
same columns as received ones, and both have an "other attributes" column
for what the summary had no field for, as text: aggregator, extended
communities (route targets and origins by name), AS4_PATH with its sets in
braces, originator ID, cluster list, and unknown attributes in hex. The
API has them as summary.other; the JSON stays in `attributes`.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A route learned from one router of our AS went to no other (RFC 4271
§9.2.1), so every router needed a session with every other. A router at
the end of a single link, with one session to its neighbour inside the AS,
heard only of what that neighbour learned itself, and nothing of what the
neighbour had from the routers behind it.
A peer in our own AS can now be made a route reflector client
(`route_reflector_client`, RFC 4456). What a client sends goes to all our
routers; what the others send goes to the clients. A reflected route gets
ORIGINATOR_ID (where it started, if it does not say) and our cluster ID at
the front of CLUSTER_LIST; it is not sent back to the router it started
at, nor round to a cluster it has been through, and one that comes back
anyway is refused as "route reflected back to us". The cluster ID is the
router ID unless `cluster_id` says otherwise. The two attributes are now
decoded as such rather than kept as bytes, and are never sent to other
networks.
Unlike a standard reflector, this one is the next hop of what it reflects,
as it is of everything it announces: there is no resolving a next hop
that is not a neighbour, so a client reaches what lies behind another
router through the reflector.
Only peers in our own AS can be clients; the configuration refuses the
setting for any other. Nothing changes in what other networks are told:
Only to Customer marks go along with reflected routes, and every
receiving session keeps its own max_prefixes.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The import policy did the same to every route of a session. Now `rules`
can do more to some of them: those with certain communities, those for
certain prefixes, or both. Each rule can set the local preference and put
communities on; each route takes the first rule that holds for it.
Rules see a route as the session's own statements leave it, with our
communities taken off and the session's marks put on. So a router can act
on where another router of ours learned a route, by the mark that router
put on it, and a customer's single prefix can be marked for a prepend.
Routes of one UPDATE that different rules hold for go into the table with
attribute sets of their own. An UPDATE that no rule touches is taken as
before, without its attributes being written out again.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Control communities could say which peers a route goes to, by AS. Now
they can also name sessions by group, and ask for prepends:
L:11:P .. L:13:P our AS once to three times more towards AS P
(P 0: towards every peer in another AS)
L:20:G / L:21:G not to / only to the sessions of group G
L:31:G .. L:33:G our AS once to three times more towards group G
A group is a number given to sessions in the configuration (`groups` of
a peer): those at one exchange, or those over one link. The same network
at two exchanges is one AS but two sessions, which is what steering
inbound traffic between exchanges needs. Of several prepends that apply
the most counts, on top of the session's own as_path_prepend. Functions
2 to 9, as the documentation already promised, and 100 and up stay
informational; 10 to 99 are kept for actions to come.
They are acted on where a route leaves our AS, and taken off there; our
informational communities are not. To a peer in our own AS a route goes
with them, unchanged, so that a mark put on at one router is acted on at
another. Before, they were acted on and taken off on internal sessions
too, so a route marked "to nobody" did not even reach our own routers.
And they are ours to give: the communities of our own AS (L:n, L:n:m,
and 0:n where control communities are on) are taken off every route
from a peer in another AS as it comes in, before import marks are put
on. A peer at an exchange could otherwise decide where its routes go
from us, and set our informational marks. A customer that is to steer
its own routes is given import.accept_control_communities. An UPDATE
without any of ours is still taken as it came, without being written
out again.
This changes what a customer that set control communities gets: it now
needs accept_control_communities. The transit example and the interop
lab say so; the lab also has FRR, as a customer, ask for a prepend
towards BIRD's group, and BIRD, as a provider, have its "not to" taken
off.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Two routers of an AS that both originate a prefix (anycast) each
announce it to the other over their internal session. Each took the
other's route, could not install it in the kernel, since the prefix is
on one of its own interfaces, and so held it, counted as rejected with
"next hop unreachable": a permanent rejection on a healthy session, for
a next hop that was in fact fine.
A route from a peer in our own AS for a prefix this router originates
is now ignored: not taken, not held, not counted. Only that prefix
itself; what is inside it is judged as usual. From other networks such
routes are refused as our own prefixes, as before.
A route that is held because its prefix is a network of this machine,
or inside one (an exchange's LAN prefix, say), is now counted as "prefix
is a network of this router", apart from routes whose next hop cannot
be reached.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A validator that is still running its first validation answers a query
with No Data Available (error code 2). That ended the session, and the
next attempt came after the retry interval: 600 seconds when the cache
had not yet said otherwise, which it cannot have before it has data.
For those ten minutes after a validator started, nothing was validated.
No Data Available is now asked again after 30 seconds, or after
retry_seconds if that is shorter, and logged as information rather than
as a warning. Other failures wait as before, after trying the next
cache if there is one.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A peer that restarts keeps its routes with us, and we keep ours with our
peers while we restart, so that a restart withdraws nothing across the
network and the machine goes on forwarding. On by default for every
peer; `graceful_restart` sets the restart time we give, caps how long a
peer's routes are kept, or turns it off.
When a peer restarts: its routes are marked stale in the routing table,
and chosen as before, for at most its restart time. When it is back, what
it sends again is fresh, and the stale routes of a family go at its
End-of-RIB marker, or after the cap; at once for a family whose
forwarding it did not keep. Only a connection that failed counts as a
restart, and, with RFC 8538 agreed, an expired hold timer or a
NOTIFICATION other than a Hard Reset. The stale mark is a bit of the
route's word that selection never looks at.
When we restart: SIGUSR1 leaves the kernel's routes where they are,
closes the sessions without a word where graceful restart is agreed, and
exits with status 75, on which the systemd unit starts us again. The next
start finds the routes in the kernel, says so in its OPENs (R, and F where
forwarding was kept), and has them go once every peer has sent its
End-of-RIB. Our own End-of-RIB markers for learned routes wait for that
too. SIGTERM still stops for good, now with a Hard Reset where RFC 8538 is
agreed, as are errors of ours.
The status page and API show what was agreed with each peer, the routes
kept while a peer restarts, and which routes are stale. Tested against
FRR and BIRD in a new phase of the interoperability lab, and with routes
kept in a real kernel over a restart.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The "refused" column counted rejected announcements since the start, not
routes, which made two peers that send the same routes look different
when one of them re-sends more often. It is now "rejected announcements",
with the held routes, the number that compares, beside it as "held now".
The page says "rejected" throughout, as the documentation and metrics do.
Rows are highlighted under the pointer, and pointing at an AS number
shows its holder's name, which the browser asks RIPEstat for. The daemon
looks nothing up; the monitoring page says what the browser sends where.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A route with the BLACKHOLE community (RFC 7999) asks for the traffic to
its prefix to be dropped. Exchange route servers pass these on as host
routes with the exchange's blackhole address as next hop, and they were
rejected as "prefix too specific", which hid what they are.
Routes from EBGP neighbors with BLACKHOLE are now rejected as "blackhole
request", whatever their length. One short enough to pass would have
been taken as an ordinary route, sending the traffic to the blackhole
next hop: the request honoured without anyone having chosen to. Acting
on blackhole requests is not supported; the import policy page and the
standards list say so.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A rejected route was recorded with its prefix, reason and AS path, which
is not enough to tell why a neighbor sent it: whether a /32 is a
blackhole request, which communities a leaked route carries, which
network marked it Only to Customer.
Each recorded rejection now keeps the attributes of the UPDATE it came
in, without the NLRI of MP_REACH_NLRI and MP_UNREACH_NLRI, and its next
hop. The attributes are copied once per UPDATE, only when a route of it
is rejected, and shared by its rejected routes. A route rejected later,
when the RPKI data changes, has the attributes it was stored with.
/api/routes/rejected gives them as `summary` and `attributes`, as for
received routes, and the status page shows them under "show" in each
row of the refused routes.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
scripts/build-static.sh builds the daemon for x86_64 Linux against
musl, as one executable without dependencies to copy to a router. It
finds a musl C compiler for jemalloc (musl-cross on macOS, musl-gcc on
Linux), and uses its ar and ranlib too: with the host's, a build from
macOS gets an empty libjemalloc.a and fails to link. It prints the
revision and the SHA-256 of the result.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A full table from several neighbors means millions of small, long-lived
allocations that are replaced as routes change. jemalloc keeps the
resident size of such a workload closer to what is in use than the
system allocator does, glibc's in particular, and does not depend on
the C library the binary is linked with. Not on MSVC, which jemalloc
does not support.
Building now needs a C compiler and make; the installation page says
so.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The blue two-colour treatment is replaced by the photograph's own
colours, slightly darkened, under a neutral shade that keeps the text
legible.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The documentation moves from READMEs into a site in docs/: getting
started, a user guide, operations, a reference, and development pages,
written in the style of network vendors' documentation (docs/STYLE.md).
bin/bgp/README.md and docs/RFCs.md are folded into it.
- A theme of its own in the International Typographic Style, in blues,
with self-hosted Inter and JetBrains Mono, search over Zola's index,
dark mode, and no resources loaded from other hosts.
- Example configurations in docs/examples/, shown on the pages and
checked with `bgp --check` in CI.
- A test that fails when a field of config.proto is missing from the
configuration reference.
- A CI job that builds the site; Zola fails on broken links and anchors.
- A hardened systemd unit, tried under systemd with kernel routes on.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
What was to be scripted is configuration, done natively:
- import { add_communities, add_large_communities, remove_communities,
local_pref }: every route taken from a peer is marked (where it was
learned, say), with nobody else's word for our marks taken, and given
its preference, which selection goes by.
- export { add_communities, add_large_communities, remove_communities,
as_path_prepend, learned_routes }, for a peer or for all that have none
of their own.
- control_communities: the communities by which routes say which peers
they are passed on to, as exchanges' route servers have them (0:P, L:P,
0:L, and the large forms L:0:P, L:1:P, L:0:0), taken off as the route
goes on.
And what the last of these is for: with export.learned_routes a peer is
told the best route of every prefix the others announced. The rules are
BGP's and cannot be turned off: not back where it came from, not to a
peer whose AS is on the path, not between two internal peers, not past
NO_EXPORT or NO_ADVERTISE; our AS on the path and ourselves as next hop
to another network, LOCAL_PREF to our own; to a route server's client
the path, MED and next hop as they came (RFC 7947). Which routes go where
follows from the roles of RFC 9234: a route that came down or across goes
on down only, so that with roles on every peer this makes us transit for
our customers and nothing else. A peer without a role is told everything,
and the daemon says so at startup.
Each session follows the table's best routes with a reader and keeps the
prefixes it has announced, so that it can withdraw them. Routes that go
out alike go in one UPDATE: changes are gathered for 50 ms first, and a
table that is given out anew is gathered whole (at most four sessions at
a time; it is tens of megabytes). For that to work the table's journal
had to give out together what was written together: every change now
carries a time on a table-wide clock, a reader's pass reads every shard
up to one time, no further than the changes that are complete in every
shard, and a resync takes its places in the journals as of one time.
One peer sending 1.23 M routes over a session, another told of them:
in our table after 0.47 s, all heard after 2.1 s, four routes an UPDATE.
The lab has a phase, transit: FRR as our customer and BIRD as our
provider, routes each way with the right paths and marks, one kept back
by a community, and pings between their networks through us.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Where routes go into the kernel, a route the kernel could not be given
is no longer taken into the table: its next hop is no neighbor on any
interface, or its prefix is a network the machine is itself on. Such a
route used to be able to win selection and then leave its prefix without
a route in the kernel, though another peer had one that worked.
It is held aside the way an RPKI-invalid route is, and by the same
means: judged on arrival against the interfaces as the kernel last
described them, looked for in the table when they change, and taken
from what is held when its next hop can be reached. The fib publishes
the interfaces for this; the next hop is resolved once for an UPDATE
and not for each of its routes.
The lab has a phase, nexthops: FRR's better route with a next hop that
is nowhere is held and BIRD's is installed, and they change places as
an address comes and goes.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
What the code-health review found, and what a fuzz target written for it
found in its first seconds.
- A set of attributes with the same attribute twice is refused by the
routing table. Its readers (the selection key, the path, the next hop)
could each take a different one of the two. The decoder never lets one
through; the new fuzz target `attrs` found that the table would.
- bgp_peer_up{peer}, to alert on a peer going away, and bgp_build_info.
Every metric is there from the first scrape. Alerts for a peer down,
hijack attempts and kernel errors are in the README.
- `bgp --check config` validates a configuration without starting, and
`--version` says which build it is. CI runs the first on the example
configuration, which a test now also parses with its commented fields
put in; the example had to learn about the next hop check.
- Path attributes have a module of their own, packet::attributes,
re-exported from packet::message as before.
- policy::From, which shadowed the trait, is RouteSource. The server's
connection, dialer and fsm modules are private. Logging arguments live
in the binary; the server library no longer depends on clap.
- One is_unicast_link_local (the standard library's) instead of two of
our own; SelectionKey::origin(); one place where an Import is made.
- READMEs say what the daemon does today rather than what it did not do
a year ago. Documentation links are checked in CI. Unused dependencies
and bgp_web::serve are gone; the Docker build is --locked and does not
ship the fuzz corpus.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Three independent reviews (hijack resistance, reliability, code health)
of the whole tree. This is what they found that could let a bad route in
or take the daemon down.
Hijacks:
- A route had two paths on a two-octet session, AS_PATH and AS4_PATH,
read in two places by two rules. A peer could make the origin checked
on import differ from the one checked at revalidation, and get an
RPKI-invalid route into the table. AS4_PATH is now merged into AS_PATH
once, on receipt (RFC 6793 §4.2.3), and nothing else knows of it.
- The next hop is judged on import: it must be usable, agreed on
(RFC 8950), and by default the peer itself.
- Our own originated prefixes are not taken from other networks.
- A route for a network the machine is on is never put in the kernel.
- Paths with an AS_SET are refused (RFC 9774).
- A configured peer gets one session, not one per BGP Identifier.
- More IPv6 special-purpose prefixes are bogons.
Reliability:
- A batch of requests the kernel refused could overflow the netlink
socket and end the daemon. The socket has room now, a lost answer or a
silent kernel means asking what is there, and neither is fatal.
- Working the routes out again within the grace period after a restart
no longer drops the routes being kept.
- That work can no longer be put off for ever by interface changes.
- Peers whose sessions keep failing are slowed down.
- Unused attribute sets are swept when they pile up, not only each
minute.
- Log lines a peer can cause are said once in a while.
- An RTR answer is bounded in size and time; data cannot expire between
two refreshes.
- The shard of a key is taken from a stirred hash: neighbouring bits of
the hash proved alike for prefixes in a row. The test that showed it,
failing one run in sixteen, is deterministic now.
The lab has a phase, hijacks, in which FRR tries the first three.
route::apply is a struct with methods instead of nested closures, and
the kernel task's loop is shorter.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
A peer's endpoint may be a link-local IPv6 address with the interface it
is on. Such a peer is the address and the interface together, wherever
peers are told apart: admission, collisions, hold-downs, the refusal log,
the status page. The interface is looked up by name each time it is
needed, so one that appears later or is made anew is found.
Our routes go out with our link-local address in both places of
MP_REACH_NLRI's next hop, as FRR sends its own. A peer's link-local next
hop is taken alone, twice, or after "::" (BIRD), and resolved in the
kernel on the interface of the session rather than by looking fe80::/64
up, which every interface has.
The lab has a new phase, linklocal: sessions with FRR (by interface, with
radvd beside the daemon) and BIRD over a LAN with link-local addresses
only, both families, pings across, the interface down and up.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
For a link that has only IPv6 addresses.
- The Extended Next Hop capability is offered on every session over IPv6
whose families include IPv4 unicast, and used if the peer offers it too.
Nothing to configure.
- On such a session our IPv4 routes go out in MP_REACH_NLRI with the
session's IPv6 address as next hop, and are withdrawn in
MP_UNREACH_NLRI. Without the agreement they are not sent, as before.
- IPv4 routes are read with an IPv6 next hop, global or global with
link-local.
- The kernel installer resolves an IPv4 route's IPv6 next hop like any
other and installs it: by way of an IPv6 nexthop object, or with RTA_VIA
where routes carry their own gateway.
Tested against a real kernel in both modes, with a link-local next hop
too, and in the lab against FRR and BIRD: the new `v6only` phase takes
the IPv4 addresses off the exchange LAN, runs one IPv6 session with each
router for both families, and pings IPv4 across.
Sessions between link-local addresses are not supported yet.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
New crate bgp-fib. It follows the routing table's best routes and keeps
the kernel's routing table the same, and learns the machine's interfaces
and addresses from the kernel, which is what says whether a next hop can
be reached.
- netlink: the rtnetlink messages used (routes, addresses, links, errors),
as bytes and back. No I/O; property tested and fuzzed.
- interfaces: what is directly reachable, and from which interface.
- plan: what to ask the kernel for, given the best routes and what the
kernel has. No I/O; tested against a model kernel.
- kernel (Linux only): the sockets and the task. Requests go in batches;
routes of ours found at startup are kept if still right and removed if
not; a change of interfaces has every route worked out again; a clean
stop removes our routes.
Only routes marked proto bgp with the configured table and metric are
ever touched. A best route is installed if its next hop is a neighbor;
next hops further away are not resolved through other routes yet, and
such prefixes are counted and shown instead.
Configured with `kernel { table metric }`; off by default. The daemon
needs CAP_NET_ADMIN and stops if the kernel refuses it. On shutdown it
closes sessions and then removes its routes.
/api/kernel and the status page show installed, unresolved and refused
counts, the last error and the interfaces; five bgp_kernel_* metrics.
Testing: scripts/kernel-tests.sh runs, in network namespaces of their
own and with only the capabilities the daemon needs, the installer
against `ip route`, the daemon with a peer, and two daemons that route
for each other with pings across over IPv4 and IPv6.
scripts/linux-vm.sh runs that, or anything else, in a Lima VM from
macOS. CI runs the kernel tests and fuzzes the netlink decoder.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
A peer's configured role now does three more things:
- Our OPEN carries the BGP Role capability with what we are to the peer.
A peer whose own says it is something that does not pair with that, or
that sends two different roles, is refused with OPEN Message Error /
Role Mismatch. A peer that says nothing is accepted unless require_role
is set. A role on a peer in our own AS is a configuration error.
- Routes from a provider, a peer or a route server are marked Only to
Customer on the way in if they are not already, and our routes are
marked on the way out to a customer, a peer or a route server client.
- A marked route from a customer or route server client, or from a peer
with someone else's mark, is a leak and is refused. No policy setting
turns that off.
The packet crate gains the Only to Customer attribute (malformed:
treat-as-withdraw), and the Role Mismatch subcode is corrected from 8 to
11.
The status page shows whether the peer confirmed its role.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Origin validation says who may originate a prefix and nothing about the
rest of the path: it does not catch a route leak, nor a hijack that keeps
the right origin at the end of a made-up path. ASPAs, in which a network
lists its providers, do.
bgp-rpki:
- aspa: the ASPAs and the upstream and downstream verification procedures
of draft-ietf-sidrops-aspa-verification-24, tested against the draft's
wording as written.
- rtr: protocol version 2 (draft-ietf-sidrops-8210bis-23) with the ASPA
PDU and the new error codes.
- client: asks for version 2 and falls back to whatever older version the
cache speaks; keeps ASPAs with the VRPs, applied whole or not at all;
publishes which customers' ASPAs changed; tells the cache why it is
being left (Error Report); does not ask one version's serial of another.
Server:
- A peer has a role (provider, customer, peer, route server, route server
client), which decides how its paths are verified. Without one they are
not.
- A route whose path is invalid is refused ("ASPA invalid") and held, like
one with an invalid origin; accept_aspa_invalid exempts a peer.
- When ASPAs change, routes in the table whose path has a changed customer
on it are verified again, and held routes are released when they pass
both checks.
- The revalidator finds a route's peer by index instead of searching a
list for every route.
The status page and API show each peer's role, each route's path validity,
the number of ASPAs and the RTR version in use; bgp_rpki_aspas is on
/metricz.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
With rpki { caches { ... } } in the configuration the server keeps the
validated ROA payloads of a validator and validates every route from a
peer outside its own AS (RFC 6811). An invalid route is refused, unless
its peer has accept_rpki_invalid. Valid and not-found routes are taken;
validity does not otherwise enter route selection.
Validity is not settled when a route arrives: the data changes every few
minutes. The routes follow, without the peer sending anything again.
- A route refused as invalid is held by its session, out of the table.
When the data changes the session looks at what it holds, and what is
no longer invalid goes into the table. A held route is the peer's to
withdraw or replace like any other.
- A route in the table that becomes invalid is found by a task that
looks through the table when the data changes, at the prefixes the
changed VRPs cover, and is taken out and held by its session.
- If the data expires because no cache confirms it, nothing is invalid
any more and everything held is taken.
- A session holds at most 200,000 routes; past that it asks the peer for
a route refresh when the data changes.
So that the table can be looked through without parsing attributes, an
attribute set's key now has the route's origin AS. Memory per route is
unchanged at 52 bytes on the real table.
Shown: /api/rpki and a section of the status page with the cache, its
state and the age of the data; each route's validity; each peer's count
of held routes. Refusals are recorded under "RPKI invalid". Metrics:
bgp_rpki_vrps and bgp_rpki_updates_total.
Also: Negotiated says whether the peer supports route refresh, and
docs/RFCs.md is brought up to date.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
