From 024ee930cb3c9ae49e4266aee89cfde0ebb407e1 Mon Sep 17 00:00:00 2001 From: Peilin Ye Date: Tue, 14 Nov 2023 01:42:17 +0100 Subject: [PATCH] bpf: Fix dev's rx stats for bpf_redirect_peer traffic Traffic redirected by bpf_redirect_peer() (used by recent CNIs like Cilium) is not accounted for in the RX stats of supported devices (that is, veth and netkit), confusing user space metrics collectors such as cAdvisor [0], as reported by Youlun. Fix it by calling dev_sw_netstats_rx_add() in skb_do_redirect(), to update RX traffic counters. Devices that support ndo_get_peer_dev _must_ use the @tstats per-CPU counters (instead of @lstats, or @dstats). To make this more fool-proof, error out when ndo_get_peer_dev is set but @tstats are not selected. [0] Specifically, the "container_network_receive_{byte,packet}s_total" counters are affected. Fixes: 9aa1206e8f48 ("bpf: Add redirect_peer helper") Reported-by: Youlun Zhang Signed-off-by: Peilin Ye Co-developed-by: Daniel Borkmann Signed-off-by: Daniel Borkmann Reviewed-by: Nikolay Aleksandrov Link: https://lore.kernel.org/r/20231114004220.6495-6-daniel@iogearbox.net Signed-off-by: Martin KaFai Lau --- net/core/dev.c | 8 ++++++++ net/core/filter.c | 1 + 2 files changed, 9 insertions(+) diff --git a/net/core/dev.c b/net/core/dev.c index 0cc6e283edba..c879246be48d 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -10055,6 +10055,14 @@ static int netdev_do_alloc_pcpu_stats(struct net_device *dev) { void __percpu *v; + /* Drivers implementing ndo_get_peer_dev must support tstat + * accounting, so that skb_do_redirect() can bump the dev's + * RX stats upon network namespace switch. + */ + if (dev->netdev_ops->ndo_get_peer_dev && + dev->pcpu_stat_type != NETDEV_PCPU_STAT_TSTATS) + return -EOPNOTSUPP; + switch (dev->pcpu_stat_type) { case NETDEV_PCPU_STAT_NONE: return 0; diff --git a/net/core/filter.c b/net/core/filter.c index 383f96b0a1c7..cca810987c8d 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2492,6 +2492,7 @@ int skb_do_redirect(struct sk_buff *skb) net_eq(net, dev_net(dev)))) goto out_drop; skb->dev = dev; + dev_sw_netstats_rx_add(dev, skb->len); return -EAGAIN; } return flags & BPF_F_NEIGH ? -- 2.39.5