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authorYan Zhai <yan@cloudflare.com>2023-12-04 11:33:28 -0800
committerJakub Kicinski <kuba@kernel.org>2023-12-05 20:49:40 -0800
commit2f57dd94bdef083855366138646b26b05f410d99 (patch)
treefe70ed53771fe6e27cc88289f414c6598a6e62cd /net/packet
parent19b707c3f23a7923ab40732521123d9b59965cc4 (diff)
packet: add a generic drop reason for receive
Commit da37845fdce2 ("packet: uses kfree_skb() for errors.") switches from consume_skb to kfree_skb to improve error handling. However, this could bring a lot of noises when we monitor real packet drops in kfree_skb[1], because in tpacket_rcv or packet_rcv only packet clones can be freed, not actual packets. Adding a generic drop reason to allow distinguish these "clone drops". [1]: https://lore.kernel.org/netdev/CABWYdi00L+O30Q=Zah28QwZ_5RU-xcxLFUK2Zj08A8MrLk9jzg@mail.gmail.com/ Fixes: da37845fdce2 ("packet: uses kfree_skb() for errors.") Suggested-by: Eric Dumazet <edumazet@google.com> Suggested-by: Willem de Bruijn <willemdebruijn.kernel@gmail.com> Signed-off-by: Yan Zhai <yan@cloudflare.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://lore.kernel.org/r/ZW4piNbx3IenYnuw@debian.debian Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/packet')
-rw-r--r--net/packet/af_packet.c20
1 files changed, 7 insertions, 13 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index a84e00b5904b..f92edba4c40f 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2121,13 +2121,13 @@ static int packet_rcv_vnet(struct msghdr *msg, const struct sk_buff *skb,
static int packet_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt, struct net_device *orig_dev)
{
+ enum skb_drop_reason drop_reason = SKB_CONSUMED;
struct sock *sk;
struct sockaddr_ll *sll;
struct packet_sock *po;
u8 *skb_head = skb->data;
int skb_len = skb->len;
unsigned int snaplen, res;
- bool is_drop_n_account = false;
if (skb->pkt_type == PACKET_LOOPBACK)
goto drop;
@@ -2217,9 +2217,9 @@ static int packet_rcv(struct sk_buff *skb, struct net_device *dev,
return 0;
drop_n_acct:
- is_drop_n_account = true;
atomic_inc(&po->tp_drops);
atomic_inc(&sk->sk_drops);
+ drop_reason = SKB_DROP_REASON_PACKET_SOCK_ERROR;
drop_n_restore:
if (skb_head != skb->data && skb_shared(skb)) {
@@ -2227,16 +2227,14 @@ drop_n_restore:
skb->len = skb_len;
}
drop:
- if (!is_drop_n_account)
- consume_skb(skb);
- else
- kfree_skb(skb);
+ kfree_skb_reason(skb, drop_reason);
return 0;
}
static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt, struct net_device *orig_dev)
{
+ enum skb_drop_reason drop_reason = SKB_CONSUMED;
struct sock *sk;
struct packet_sock *po;
struct sockaddr_ll *sll;
@@ -2250,7 +2248,6 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
struct sk_buff *copy_skb = NULL;
struct timespec64 ts;
__u32 ts_status;
- bool is_drop_n_account = false;
unsigned int slot_id = 0;
int vnet_hdr_sz = 0;
@@ -2498,19 +2495,16 @@ drop_n_restore:
skb->len = skb_len;
}
drop:
- if (!is_drop_n_account)
- consume_skb(skb);
- else
- kfree_skb(skb);
+ kfree_skb_reason(skb, drop_reason);
return 0;
drop_n_account:
spin_unlock(&sk->sk_receive_queue.lock);
atomic_inc(&po->tp_drops);
- is_drop_n_account = true;
+ drop_reason = SKB_DROP_REASON_PACKET_SOCK_ERROR;
sk->sk_data_ready(sk);
- kfree_skb(copy_skb);
+ kfree_skb_reason(copy_skb, drop_reason);
goto drop_n_restore;
}