linux-kernel - Re: [PATCH net-next v2] net: pppoe: implement GRO support

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

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <5f250beb-6a81-42b2-bf6f-da02c04cbf15@redhat.com>
Date: Tue, 22 Jul 2025 10:36:31 +0200
From: Paolo Abeni <pabeni@...hat.com>
To: Felix Fietkau <nbd@....name>, netdev@...r.kernel.org,
 Michal Ostrowski <mostrows@...thlink.net>,
 Andrew Lunn <andrew+netdev@...n.ch>, "David S. Miller"
 <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
 Jakub Kicinski <kuba@...nel.org>
Cc: linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next v2] net: pppoe: implement GRO support

On 7/16/25 10:14 AM, Felix Fietkau wrote:
> +static struct sk_buff *pppoe_gro_receive(struct list_head *head,
> +					 struct sk_buff *skb)
> +{
> +	const struct packet_offload *ptype;
> +	unsigned int hlen, off_pppoe;
> +	struct sk_buff *pp = NULL;
> +	struct pppoe_hdr *phdr;
> +	struct sk_buff *p;
> +	__be16 type;
> +	int flush = 1;

Minor nit: please respect the reverse christmas tree order above

> +	off_pppoe = skb_gro_offset(skb);
> +	hlen = off_pppoe + sizeof(*phdr) + 2;
> +	phdr = skb_gro_header(skb, hlen, off_pppoe);
> +	if (unlikely(!phdr))
> +		goto out;
> +
> +	/* ignore packets with padding or invalid length */
> +	if (skb_gro_len(skb) != be16_to_cpu(phdr->length) + hlen - 2)
> +		goto out;
> +
> +	NAPI_GRO_CB(skb)->network_offsets[NAPI_GRO_CB(skb)->encap_mark] = hlen;
> +
> +	type = pppoe_hdr_proto(phdr);
> +	if (!type)
> +		goto out;
> +
> +	ptype = gro_find_receive_by_type(type);
> +	if (!ptype)
> +		goto out;
> +
> +	flush = 0;
> +
> +	list_for_each_entry(p, head, list) {
> +		struct pppoe_hdr *phdr2;
> +
> +		if (!NAPI_GRO_CB(p)->same_flow)
> +			continue;
> +
> +		phdr2 = (struct pppoe_hdr *)(p->data + off_pppoe);
> +		if (compare_pppoe_header(phdr, phdr2))
> +			NAPI_GRO_CB(p)->same_flow = 0;
> +	}
> +
> +	skb_gro_pull(skb, sizeof(*phdr) + 2);
> +	skb_gro_postpull_rcsum(skb, phdr, sizeof(*phdr) + 2);
> +
> +	pp = ptype->callbacks.gro_receive(head, skb);

Here you can use INDIRECT_CALL_INET()

> +
> +out:
> +	skb_gro_flush_final(skb, pp, flush);
> +
> +	return pp;
> +}
> +
> +static int pppoe_gro_complete(struct sk_buff *skb, int nhoff)
> +{
> +	struct pppoe_hdr *phdr = (struct pppoe_hdr *)(skb->data + nhoff);
> +	__be16 type = pppoe_hdr_proto(phdr);
> +	struct packet_offload *ptype;
> +	int err = -ENOENT;
> +
> +	ptype = gro_find_complete_by_type(type);
> +	if (ptype)
> +		err = ptype->callbacks.gro_complete(skb, nhoff +
> +						    sizeof(*phdr) + 2);

Possibly even here but it's less relevant.

> +
> +	return err;
> +}
> +
> +static struct packet_offload pppoe_packet_offload __read_mostly = {
> +	.type = cpu_to_be16(ETH_P_PPP_SES),
> +	.priority = 10,

The priority value should be IMHO greater then the exiting ones to avoid
possible regressions on other protocols. i.e. 20 should do.

Thanks,

Paolo