mirror of
https://github.com/livekit/livekit.git
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David Chen
132 lines
5.4 KiB
Bash
132 lines
5.4 KiB
Bash
#!/usr/bin/env bash
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#
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# Linux network-namespace + netem harness for the asymmetric teleop FlexFEC test.
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#
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# Topology (models a robot on a lossy 5G uplink talking to a wired operator):
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#
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# robot netns (publisher) root netns (SFU + subscriber/operator)
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# 10.200.0.2 veth-robot <=========> veth-host 10.200.0.1 [SFU :7880/:7882]
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# netem here [subscriber -> 10.200.0.1]
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#
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# Only the robot<->SFU leg traverses the veth pair, so netem on the veth shapes the
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# robot uplink/downlink ONLY. The subscriber (operator) sits in the root netns and reaches
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# the SFU at 10.200.0.1 locally, so its link stays clean -- exactly the teleop case where
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# the robot is on 5G and the operator is on a stable hardline.
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#
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# Loss is applied to the robot->SFU (uplink) direction; delay is applied symmetrically so a
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# NACK->RTX recovery costs a full RTT (the latency publisher-side FlexFEC avoids by letting
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# the SFU repair the stream inline).
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#
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# Usage:
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# sudo scripts/flexfec/netns.sh up # create ns + veth (no impairment)
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# sudo scripts/flexfec/netns.sh shape <loss%> <owd_ms> # apply/replace netem
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# sudo scripts/flexfec/netns.sh clear # remove netem (clean link)
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# sudo scripts/flexfec/netns.sh status # show qdiscs + addrs
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# sudo scripts/flexfec/netns.sh down # tear everything down
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# scripts/flexfec/netns.sh exec <cmd...> # run cmd inside robot netns (as $SUDO_USER)
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#
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# Example:
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# sudo scripts/flexfec/netns.sh up
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# sudo scripts/flexfec/netns.sh shape 3 20 # 3% uplink loss, 20ms each way (40ms RTT)
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set -euo pipefail
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NS=robot
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VETH_HOST=veth-host
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VETH_ROBOT=veth-robot
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HOST_IP=10.200.0.1
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ROBOT_IP=10.200.0.2
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PREFIX=24
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# Privileged commands are run via passwordless sudo for ip/tc only (see the sudoers drop-in
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# in the harness docs). The script itself does NOT need to run as root.
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if [[ "$(id -u)" == "0" ]]; then
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SUDO=""
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else
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SUDO="sudo -n"
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fi
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cmd_up() {
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# Idempotent: tear down any prior instance first.
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$SUDO ip netns del "$NS" 2>/dev/null || true
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$SUDO ip link del "$VETH_HOST" 2>/dev/null || true
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$SUDO ip netns add "$NS"
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$SUDO ip link add "$VETH_HOST" type veth peer name "$VETH_ROBOT"
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$SUDO ip link set "$VETH_ROBOT" netns "$NS"
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$SUDO ip addr add "$HOST_IP/$PREFIX" dev "$VETH_HOST"
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$SUDO ip link set "$VETH_HOST" up
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$SUDO ip netns exec "$NS" ip addr add "$ROBOT_IP/$PREFIX" dev "$VETH_ROBOT"
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$SUDO ip netns exec "$NS" ip link set "$VETH_ROBOT" up
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$SUDO ip netns exec "$NS" ip link set lo up
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echo "up: $NS netns ready"
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echo " root: $VETH_HOST $HOST_IP/$PREFIX robot: $VETH_ROBOT $ROBOT_IP/$PREFIX"
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echo " SFU should advertise $HOST_IP (use flexfec-linux.yaml); publisher connects to ws://$HOST_IP:7880"
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}
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# shape <loss_percent> <one_way_delay_ms> [jitter_ms] [corr_pct]
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# When jitter_ms/corr_pct are given they feed netem's loss correlation + delay jitter to
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# approximate bursty (e.g. 5G handoff) conditions rather than uniform random loss.
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cmd_shape() {
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local loss="${1:?usage: shape <loss%> <owd_ms> [jitter_ms] [loss_corr%]}"
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local owd="${2:?usage: shape <loss%> <owd_ms> [jitter_ms] [loss_corr%]}"
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local jitter="${3:-0}"
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local corr="${4:-0}"
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local delayspec="delay ${owd}ms"
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[[ "$jitter" != "0" ]] && delayspec="delay ${owd}ms ${jitter}ms distribution normal"
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local lossspec="loss ${loss}%"
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[[ "$corr" != "0" ]] && lossspec="loss ${loss}% ${corr}%"
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# Uplink (robot -> SFU): loss + delay. Applied on robot-side egress.
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$SUDO ip netns exec "$NS" tc qdisc replace dev "$VETH_ROBOT" root netem $delayspec $lossspec
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# Downlink (SFU -> robot, carries NACK/RTCP/PLI): delay only, no loss (operator link is
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# clean, but the return path still costs propagation delay so RTX pays a full RTT).
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$SUDO tc qdisc replace dev "$VETH_HOST" root netem delay "${owd}ms"
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echo "shape: uplink ${lossspec} ${delayspec} ; downlink delay=${owd}ms (RTT≈$((owd*2))ms)"
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}
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cmd_clear() {
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$SUDO ip netns exec "$NS" tc qdisc del dev "$VETH_ROBOT" root 2>/dev/null || true
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$SUDO tc qdisc del dev "$VETH_HOST" root 2>/dev/null || true
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echo "clear: netem removed (clean link)"
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}
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cmd_status() {
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echo "=== root ns: $VETH_HOST ==="
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$SUDO ip addr show "$VETH_HOST" 2>/dev/null | sed -n '2,4p' || echo " (absent)"
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$SUDO tc qdisc show dev "$VETH_HOST" 2>/dev/null || true
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echo "=== robot ns: $VETH_ROBOT ==="
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$SUDO ip netns exec "$NS" ip addr show "$VETH_ROBOT" 2>/dev/null | sed -n '2,4p' || echo " (absent)"
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$SUDO ip netns exec "$NS" tc qdisc show dev "$VETH_ROBOT" 2>/dev/null || true
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}
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cmd_down() {
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$SUDO ip netns del "$NS" 2>/dev/null || true
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$SUDO ip link del "$VETH_HOST" 2>/dev/null || true
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echo "down: torn down"
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}
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# exec <cmd...> : run inside robot netns, dropping back to the invoking user. The outer
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# `sudo ip netns exec` runs as root; the inner `sudo -u $user` drops privileges (root -> user
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# needs no password), so the publisher runs as the normal user with its env intact.
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cmd_exec() {
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local user="${SUDO_USER:-$USER}"
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exec $SUDO ip netns exec "$NS" sudo -u "$user" --preserve-env=LIVEKIT_URL,LIVEKIT_API_KEY,LIVEKIT_API_SECRET,RUST_LOG,ROOM,PUB_IDENTITY,PATH,HOME,CARGO_HOME,RUSTUP_HOME "$@"
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}
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action="${1:-}"
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shift || true
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case "$action" in
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up) cmd_up "$@" ;;
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shape) cmd_shape "$@" ;;
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clear) cmd_clear "$@" ;;
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status) cmd_status "$@" ;;
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down) cmd_down "$@" ;;
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exec) cmd_exec "$@" ;;
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*) echo "usage: $0 {up|shape <loss%> <owd_ms>|clear|status|down|exec <cmd...>}" >&2; exit 2 ;;
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esac
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