lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Message-Id: <20220208035510.1200-3-dongli.zhang@oracle.com> Date: Mon, 7 Feb 2022 19:55:10 -0800 From: Dongli Zhang <dongli.zhang@...cle.com> To: netdev@...r.kernel.org, bpf@...r.kernel.org Cc: linux-kernel@...r.kernel.org, davem@...emloft.net, kuba@...nel.org, rostedt@...dmis.org, mingo@...hat.com, ast@...nel.org, daniel@...earbox.net, andrii@...nel.org, imagedong@...cent.com, joao.m.martins@...cle.com, joe.jin@...cle.com, dsahern@...il.com, edumazet@...gle.com Subject: [PATCH 2/2] net: tun: track dropped skb via kfree_skb_reason() The TUN can be used as vhost-net backend. E.g, the tun_net_xmit() is the interface to forward the skb from TUN to vhost-net/virtio-net. However, there are many "goto drop" in the TUN driver. Therefore, the kfree_skb_reason() is involved at each "goto drop" to help userspace ftrace/ebpf to track the reason for the loss of packets. Cc: Joao Martins <joao.m.martins@...cle.com> Cc: Joe Jin <joe.jin@...cle.com> Signed-off-by: Dongli Zhang <dongli.zhang@...cle.com> --- drivers/net/tun.c | 33 +++++++++++++++++++++++++-------- include/linux/skbuff.h | 6 ++++++ include/trace/events/skb.h | 6 ++++++ 3 files changed, 37 insertions(+), 8 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index fed85447701a..d67f2419dbb4 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1062,13 +1062,16 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) struct netdev_queue *queue; struct tun_file *tfile; int len = skb->len; + int drop_reason = SKB_DROP_REASON_NOT_SPECIFIED; rcu_read_lock(); tfile = rcu_dereference(tun->tfiles[txq]); /* Drop packet if interface is not attached */ - if (!tfile) + if (!tfile) { + drop_reason = SKB_DROP_REASON_DEV_NOT_ATTACHED; goto drop; + } if (!rcu_dereference(tun->steering_prog)) tun_automq_xmit(tun, skb); @@ -1078,19 +1081,27 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) /* Drop if the filter does not like it. * This is a noop if the filter is disabled. * Filter can be enabled only for the TAP devices. */ - if (!check_filter(&tun->txflt, skb)) + if (!check_filter(&tun->txflt, skb)) { + drop_reason = SKB_DROP_REASON_TAP_RUN_FILTER; goto drop; + } if (tfile->socket.sk->sk_filter && - sk_filter(tfile->socket.sk, skb)) + sk_filter(tfile->socket.sk, skb)) { + drop_reason = SKB_DROP_REASON_SKB_TRIM; goto drop; + } len = run_ebpf_filter(tun, skb, len); - if (len == 0 || pskb_trim(skb, len)) + if (len == 0 || pskb_trim(skb, len)) { + drop_reason = SKB_DROP_REASON_SKB_TRIM; goto drop; + } - if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC))) + if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC))) { + drop_reason = SKB_DROP_REASON_SKB_ORPHAN_FRAGS; goto drop; + } skb_tx_timestamp(skb); @@ -1101,8 +1112,10 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) nf_reset_ct(skb); - if (ptr_ring_produce(&tfile->tx_ring, skb)) + if (ptr_ring_produce(&tfile->tx_ring, skb)) { + drop_reason = SKB_DROP_REASON_PTR_FULL; goto drop; + } /* NETIF_F_LLTX requires to do our own update of trans_start */ queue = netdev_get_tx_queue(dev, txq); @@ -1119,7 +1132,7 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) drop: atomic_long_inc(&dev->tx_dropped); skb_tx_error(skb); - kfree_skb(skb); + kfree_skb_reason(skb, drop_reason); rcu_read_unlock(); return NET_XMIT_DROP; } @@ -1717,6 +1730,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, u32 rxhash = 0; int skb_xdp = 1; bool frags = tun_napi_frags_enabled(tfile); + int drop_reason = SKB_DROP_REASON_NOT_SPECIFIED; if (!(tun->flags & IFF_NO_PI)) { if (len < sizeof(pi)) @@ -1820,9 +1834,10 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, if (err) { err = -EFAULT; + drop_reason = SKB_DROP_REASON_SKB_COPY_DATA; drop: atomic_long_inc(&tun->dev->rx_dropped); - kfree_skb(skb); + kfree_skb_reason(skb, drop_reason); if (frags) { tfile->napi.skb = NULL; mutex_unlock(&tfile->napi_mutex); @@ -1869,6 +1884,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, case IFF_TAP: if (frags && !pskb_may_pull(skb, ETH_HLEN)) { err = -ENOMEM; + drop_reason = SKB_DROP_REASON_SKB_PULL; goto drop; } skb->protocol = eth_type_trans(skb, tun->dev); @@ -1922,6 +1938,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, if (unlikely(!(tun->dev->flags & IFF_UP))) { err = -EIO; rcu_read_unlock(); + drop_reason = SKB_DROP_REASON_DEV_DOWN; goto drop; } diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 16c30d2e20dc..db2ef8e8d878 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -323,8 +323,14 @@ enum skb_drop_reason { SKB_DROP_REASON_SKB_GSO_SEGMENT, SKB_DROP_REASON_SKB_CHECKSUM, SKB_DROP_REASON_SKB_COPY_DATA, + SKB_DROP_REASON_SKB_TRIM, + SKB_DROP_REASON_SKB_ORPHAN_FRAGS, + SKB_DROP_REASON_SKB_PULL, + SKB_DROP_REASON_DEV_NOT_ATTACHED, + SKB_DROP_REASON_DEV_DOWN, SKB_DROP_REASON_PTR_FULL, SKB_DROP_REASON_VIRTNET_HDR, + SKB_DROP_REASON_TAP_RUN_FILTER, SKB_DROP_REASON_MAX, }; diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h index bf1509c31cea..03121373d2f0 100644 --- a/include/trace/events/skb.h +++ b/include/trace/events/skb.h @@ -19,8 +19,14 @@ EM(SKB_DROP_REASON_SKB_GSO_SEGMENT, SKB_GSO_SEGMENT) \ EM(SKB_DROP_REASON_SKB_CHECKSUM, SKB_CHECKSUM) \ EM(SKB_DROP_REASON_SKB_COPY_DATA, SKB_COPY_DATA) \ + EM(SKB_DROP_REASON_SKB_TRIM, SKB_TRIM) \ + EM(SKB_DROP_REASON_SKB_ORPHAN_FRAGS, SKB_ORPHAN_FRAGS) \ + EM(SKB_DROP_REASON_SKB_PULL, SKB_PULL) \ + EM(SKB_DROP_REASON_DEV_NOT_ATTACHED, DEV_NOT_ATTACHED) \ + EM(SKB_DROP_REASON_DEV_DOWN, DEV_DOWN) \ EM(SKB_DROP_REASON_PTR_FULL, PTR_FULL) \ EM(SKB_DROP_REASON_VIRTNET_HDR, VIRTNET_HDR) \ + EM(SKB_DROP_REASON_TAP_RUN_FILTER, TAP_RUN_FILTER) \ EMe(SKB_DROP_REASON_MAX, MAX) #undef EM -- 2.17.1
Powered by blists - more mailing lists