Re: [PATCH net-next v10 17/19] psp: provide decapsulation and receive helper for drivers

[Daniel Zahka <daniel.zahka@gmail.com>]

On 9/2/25 6:28 AM, Paolo Abeni wrote:
> On 8/28/25 6:29 PM, Daniel Zahka wrote:
>> +/* Receive handler for PSP packets.
>> + *
>> + * Presently it accepts only already-authenticated packets and does not
>> + * support optional fields, such as virtualization cookies.
>> + */
>> +int psp_dev_rcv(struct sk_buff *skb, u16 dev_id, u8 generation, bool strip_icv)
>> +{
>> +	const struct psphdr *psph;
>> +	int depth = 0, end_depth;
>> +	struct psp_skb_ext *pse;
>> +	struct ipv6hdr *ipv6h;
>> +	struct ethhdr *eth;
>> +	int encap_bytes;
>> +	__be16 proto;
>> +
>> +	eth = (struct ethhdr *)(skb->data);
>> +	proto = __vlan_get_protocol(skb, eth->h_proto, &depth);
>> +	if (proto != htons(ETH_P_IPV6))
>> +		return -EINVAL;
>> +
>> +	ipv6h = (struct ipv6hdr *)(skb->data + depth);
>> +	depth += sizeof(*ipv6h);
>> +	end_depth = depth + sizeof(struct udphdr) + sizeof(struct psphdr);
> Why aren't you checking the next hdr being UDP? This could potentially
> match unrelated packets.

This assumes the caller knows the packet is psp transport mode packet, 
which I think could be a reasonable API given that all psp 
implementations probably involve parsing packets in hw. I will update 
this patch to properly support IPv4, though.

>
> Also I guess you need pskb_may_pull() above.

we check for: end_depth > skb_headlen(skb). If you prefer 
pskb_may_pull(), I can change it.