docs: caveats EN+PT-BR updated to the verified state (hook order, soak, states, divert/pflog consumers)

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lgcosta committed 2026-11-11 22:21:25 -03:00
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@@ -70,40 +70,46 @@ exactly when the host is out of atomic memory.
conntrack — as designed (spec §4.2).
- Output (`LOCAL_OUT` at `NF_IP_PRI_CONNTRACK+1`): PF sees locally generated
traffic **after** conntrack has already committed the entry.
- Transit egress (`POSTROUTING` at `NF_IP_PRI_LAST-1`): PF runs at the very
end — after any iptables/nft SNAT/masquerade — so `pass out … nat-to`-era
rules (M3) will be validated against this ordering. The "unregister-safe
ordering vs conntrack" warning from the design still applies: overlapping
policy between PF and conntrack is possible and yours to manage.
- Transit egress: PF evaluates the **out** ruleset at `FORWARD` (OpenBSD does
the same in `ip_forward()`), and `POSTROUTING` is skipped once that pass is
done. `nat-to`/`rdr-to` were validated against this ordering (gates 05/06).
- The "overlapping policy with conntrack" warning from the design still
applies: if iptables/nft SNAT also runs, PF's translation happens at the
layer it is hooked into, and double translation is yours to avoid.
## Control plane / lifecycle
### 6. Unload is hardened; the soak is still pending
### 6. Unload is hardened and soak-verified
`rmmod pf` deregisters `/dev/pf`, zeroes `pf_status.running` under the NET
lock, deletes **and syncs** both purge timers (they self-rearm — a real rmmod
hang was observed and fixed by stopping sources before flushing the
workqueue), unregisters hooks and flushes `pfk_netisr`. That fix is in-tree,
but the full cycle under traffic + live states (T18/soak gate) has **not**
been run to green yet. For now treat unload as admin-safe, automation-
unproven.
workqueue), unregisters hooks and flushes `pfk_netisr`. Gate `14-soak.sh`
drives ICMP+TCP traffic, checks `dmesg` for faults, then runs
`rmmod` → `insmod` → `rmmod` and compares the slab footprint before and
after: clean unload, successful reload, no growth. Unload is therefore
verified under traffic; hot-reload automation (reload while a burst is in
flight) is still not a supported workflow.
## Behavioral / rendering issues open today
## Behavioral notes verified today
### 7. `pfctl -s states` visibility anomaly (M2 gate work)
### 7. `pfctl -s states` lists real states, including translations
In the most recent captured run (gate 01): transit ping **passed** under
`keep state`, but no icmp state was listed afterwards. Fixing this is the
open item of the M2 gate work; until a green run lands, the
[state-listing row](feature-matrix.md) is the honest status. Not cosmetic if
it turns out states are not being inserted — treat both possibilities until
the gate says otherwise.
The earlier anomaly was a use-after-free: `refcnt_rele()` had inverted
polarity, so live state keys were freed while still linked in the state
RBT — that both hid states and crashed the tree walk (`pfctl -s states`
hanging the box). After the fix, gates 01/04/05/06/07 assert on the listed
states, and translated flows print both tuples (`10.0.2.1:59335
(10.0.1.10:4380) -> 10.0.2.20:8`).
### 8. Silent-but-warned stubs
### 8. Consumers still required for two features
`divert` verdicts drop with a rate-limited warning; `log` rules log nothing
with a one-time warning. Both are listed so nobody mistakes "rules loaded"
for "features active" (see [pf-guide.md](pf-guide.md)).
`divert-to` needs a process bound to the divert port (`tools/pdivert`); with
no listener the packet is dropped, exactly like BSD's `divs_noport`, and the
kernel prints `pfk: divert port N: no socket bound`. `log` needs
`tools/pflogd` reading `/dev/pflog`; without it the queue fills to its bound
(256 records / 1 MiB) and drops. Neither is a stub any more, but neither does
anything until its consumer runs (see [pf-guide.md](pf-guide.md)).
## Compat-layer deviations (from `docs/porting-notes.md`, M1 record)
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@@ -72,15 +72,16 @@ PF são best-effort exatamente quando o host está sem memória atômica.
e do conntrack — como projetado (spec §4.2).
- Saída (`LOCAL_OUT` em `NF_IP_PRI_CONNTRACK+1`): o PF vê o tráfego gerado
localmente **depois** de o conntrack já ter confirmado a entrada.
- Saída de trânsito (`POSTROUTING` em `NF_IP_PRI_LAST-1`): o PF roda no fim
da linha — depois de qualquer SNAT/masquerade do iptables/nft — então as
regras `pass out … nat-to` da era M3 serão validadas contra essa ordem. O
aviso de "ordenação segura vs conntrack" do design continua valendo: a
sobreposição de políticas entre PF e conntrack é possível e é sua.
- Saída de trânsito: o PF avalia o ruleset **out** no `FORWARD` (o OpenBSD
faz o mesmo no `ip_forward()`), e o `POSTROUTING` é pulado depois que essa
avaliação roda. `nat-to`/`rdr-to` foram validados contra essa ordem (gates
05/06).
- O aviso de "sobreposição com conntrack" continua valendo: se iptables/nft
também fizer SNAT, a tradução dupla é sua de evitar.
## Plano de controle / ciclo de vida
### 6. O unload está endurecido; o soak ainda está pendente
### 6. O unload está endurecido e verificado sob soak
O `rmmod pf` desregistra `/dev/pf`, zera `pf_status.running` sob a lock NET,
deleta **e sincroniza** os dois timers de purge (eles se rearmam sozinhos —
@@ -90,22 +91,25 @@ A correção está na árvore, mas o ciclo completo sob tráfego + estados vivos
(gate de soak T18) **ainda não** rodou verde. Por ora, trate o unload como
seguro para administração e não comprovado para automação.
## Problemas de comportamento/renderização abertos hoje
## Notas de comportamento verificadas hoje
### 7. Anomalia de visibilidade do `pfctl -s states` (trabalho do gate M2)
### 7. `pfctl -s states` lista estados reais, incluindo traduções
Na rodada capturada mais recente (gate 01): o ping de trânsito **passou** com
`keep state`, mas nenhum estado icmp foi listado depois. Corrigir isso é o
item aberto do trabalho do gate M2; até uma rodada verde, a
[linha de listagem de estados](feature-matrix.md) é o status honesto. Não é
cosmético se no fim os estados não estiverem sendo inseridos — trate as duas
possibilidades até o gate dizer o contrário.
A anomalia anterior era um use-after-free: `refcnt_rele()` tinha polaridade
invertida, então chaves de estado vivas eram liberadas ainda ligadas no RBT
de estados — o que escondia estados e quebrava o walk da árvore (`pfctl -s
states` travando a máquina). Após a correção, os gates 01/04/05/06/07
asseveram sobre os estados listados, e fluxos traduzidos imprimem as duas
tuplas (`10.0.2.1:59335 (10.0.1.10:4380) -> 10.0.2.20:8`).
### 8. Stubs silenciosos-mas-avisados
### 8. Ainda são necessários consumidores
Vereditos `divert` descartam com aviso rate-limited; regras de `log` não
logam nada e avisam uma única vez. Os dois estão listados para ninguém
confundir "regra carregou" com "feature ativa" (ver [pf-guide.md](pf-guide.md)).
`divert-to` exige um processo atrelado à porta do divert (`tools/pdivert`);
sem listener o pacote é descartado, como o `divs_noport` do BSD, e o kernel
imprime `pfk: divert port N: no socket bound`. `log` exige `tools/pflogd`
lendo `/dev/pflog`; sem ele a fila atinge o limite (256 registros / 1 MiB) e
descarta. Nenhum dos dois é mais stub, mas nenhum faz algo sem o consumidor
rodar (ver [pf-guide.md](pf-guide.md)).
## Desvios da camada de compat (de `docs/porting-notes.md`, registro do M1)
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#!/usr/bin/env bash
# M4 gate: route-to / dup-to — forced forwarding path (pf_route).
#
# Lab: cli (10.0.1.10) pings srv (10.0.2.20). Without the rule pf0 forwards it
# straight out eth2. With `route-to { 10.0.3.2 }` the packet must be pushed to
# gw2 instead - proof: gw2 captures it and the server does not see it.
# Then `dup-to { 10.0.3.2 }`: the ORIGINAL path keeps working (server sees the
# packet) AND gw2 receives a copy.
set -uo pipefail; cd "$(dirname "$0")"; . ./lib.sh
pf0 'insmod /opt/pf/pf.ko 2>/dev/null || insmod /tmp/pf.ko; true'
pf0 '/opt/pf/pfctl -e; /opt/pf/pfctl -f /dev/null' >/dev/null
GW2_DEV=$(gw2 "ip route get $CLI_IP | grep -o 'dev [a-z0-9]*' | cut -d' ' -f2")
[ -n "$GW2_DEV" ] || GW2_DEV=eth1
capture_gw2() { gw2 "(tcpdump -ni $GW2_DEV -c 4 -e icmp > /tmp/gw2.td 2>&1 &)" 2>/dev/null; }
capture_srv() { srv "(tcpdump -ni eth1 -c 4 -e icmp > /tmp/srv.td 2>&1 &)" 2>/dev/null; }
sleep 1
# --- route-to: the packet is diverted to gw2 and never reaches the server ---
cat > /tmp/g08a.conf <<C
pass in quick proto icmp from $CLI_IP to $SRV_IP route-to { $GW2_IP } keep state
pass out quick proto icmp keep state
C
pfload /tmp/g08a.conf || { bad "route-to rule load"; finish; }
pf0 '/opt/pf/pfctl -sr' | grep -q 'route-to' && ok "route-to rule listed" || bad "route-to not listed"
capture_gw2; capture_srv
cli "ping -c2 -W2 $SRV_IP >/dev/null 2>&1"
sleep 2
gw2 'cat /tmp/gw2.td' | grep -q "$SRV_IP" && ok "route-to delivered the packet to gw2" \
|| bad "gw2 did not see the routed packet"
srv 'cat /tmp/srv.td' | grep -q "$CLI_IP" && bad "server saw the packet (route not forced)" \
|| ok "normal egress bypassed"
# --- dup-to: original path still works and gw2 gets a copy ---
cat > /tmp/g08b.conf <<C
pass in quick proto icmp from $CLI_IP to $SRV_IP dup-to { $GW2_IP } keep state
pass out quick proto icmp keep state
C
pfload /tmp/g08b.conf || { bad "dup-to rule load"; finish; }
pf0 '/opt/pf/pfctl -sr' | grep -q 'dup-to' && ok "dup-to rule listed" || bad "dup-to not listed"
capture_gw2; capture_srv
cli "ping -c2 -W2 $SRV_IP >/dev/null 2>&1" && ok "dup-to did not break the flow" \
|| bad "dup-to broke the transit ping"
sleep 2
srv 'cat /tmp/srv.td' | grep -q "$CLI_IP" && ok "original path delivered" || bad "server missed the packet"
gw2 'cat /tmp/gw2.td' | grep -q "$SRV_IP" && ok "duplicate reached gw2" || bad "no duplicate at gw2"
pf0 '/opt/pf/pfctl -d' >/dev/null
finish