Re: [RFC PATCH 1/2] net: introduce per netns packet chains

[Sabrina Dubroca <sd@queasysnail.net>]

2025-03-14, 14:05:00 +0100, Paolo Abeni wrote:
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 6fa6ed5b57987..00bdd8316cb5e 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -572,11 +572,19 @@ static inline void netdev_set_addr_lockdep_class(struct net_device *dev)
>  
>  static inline struct list_head *ptype_head(const struct packet_type *pt)
>  {
> -	if (pt->type == htons(ETH_P_ALL))
> -		return pt->dev ? &pt->dev->ptype_all : &net_hotdata.ptype_all;
> -	else
> +	if (pt->type == htons(ETH_P_ALL)) {
> +		if (!pt->af_packet_net && !pt->dev)
> +			return NULL;
> +
>  		return pt->dev ? &pt->dev->ptype_specific :

s/specific/all/ ?
(ie ETH_P_ALL with pt->dev should go on &pt->dev->ptype_all like before)

> -				 &ptype_base[ntohs(pt->type) & PTYPE_HASH_MASK];
> +				 &pt->af_packet_net->ptype_all;
> +	}
> +
> +	if (pt->dev)
> +		return &pt->dev->ptype_specific;
> +
> +	return pt->af_packet_net ? &pt->af_packet_net->ptype_specific :
> +				   &ptype_base[ntohs(pt->type) & PTYPE_HASH_MASK];
>  }

[...]
> diff --git a/net/core/net-procfs.c b/net/core/net-procfs.c
> index fa6d3969734a6..8a5d93eb9d77a 100644
> --- a/net/core/net-procfs.c
> +++ b/net/core/net-procfs.c
[...]
> @@ -232,16 +233,15 @@ static void *ptype_seq_next(struct seq_file *seq, void *v, loff_t *pos)
>  				goto found;
>  			}
>  		}
> -
> -		nxt = net_hotdata.ptype_all.next;
> -		goto ptype_all;
> +		nxt = net->ptype_all.next;
> +		goto net_ptype_all;
>  	}
>  
> -	if (pt->type == htons(ETH_P_ALL)) {
> -ptype_all:
> -		if (nxt != &net_hotdata.ptype_all)
> +	if (pt->af_packet_net) {
> +net_ptype_all:
> +		if (nxt != &net->ptype_all)
>  			goto found;

This is missing similar code to find items on the new
net->ptype_specific list.

I think something like:

 	if (pt->af_packet_net) {
 net_ptype_all:
-		if (nxt != &net->ptype_all)
+		if (nxt != &net->ptype_all && nxt != &net->ptype_specific)
 			goto found;
+		if (nxt == &net->ptype_all) {
+			/* continue with ->ptype_specific if it's not empty */
+			nxt = net->ptype_specific.next;
+			if (nxt != &net->ptype_specific)
+				goto found;
+		}
 
 		nxt = ptype_base[0].next;
 	} else


(and probably something in ptype_get_idx as well)


> -		hash = 0;

hash will now be used uninitialized in the loop a bit later in the
function?

	while (nxt == &ptype_base[hash]) {

> +
>  		nxt = ptype_base[0].next;

-- 
Sabrina