Re: [PATCH net-next v2 2/4] net: hsr: emit RedBox-MAC TLV in PRP RedBox supervision frames

[Fernando Fernandez Mancera]

On Mon, 06 Jul 2026 13:41:29 +0000, Xin Xie <xiexinet@xxxxxxxxx> wrote:
> A PRP RedBox must announce the SANs it proxies so peers populate their
> proxy node tables. The proxy-announce machinery (hsr_proxy_announce(),
> armed via hsr->redbox) already iterates proxy_node_db under RCU and calls
> send_sv_frame() once per SAN, but the PRP sender emitted neither the
> announced SAN MAC nor the RedBox-MAC TLV that IEC 62439-3 requires.
> 
> Extend send_prp_supervision_frame() so that, for a proxy-announce
> (identified by the interlink port, an O(1) test), the frame carries the
> proxied SAN MAC as MacAddressA followed by the RedBox-MAC TLV (Type 30)
> and an explicit End-of-TLV marker before padding.
> 
> hsr_get_node() must also accept the reinjected proxy-announce: a PRP
> supervision frame is an untagged ETH_P_PRP frame (mac_len == ETH_HLEN, the
> RCT is appended only on egress) sourced from macaddress_redbox, which is
> never learned from data. Exempt only PRP supervision frames from the
> hsr_ethhdr length guard; HSR (ETH_P_HSR) supervision is front-tagged and
> keeps the original guard, so HSR malformed-frame filtering is unchanged.
> 
> Also align macaddress_redbox so that ether_addr_copy() and
> ether_addr_equal() on it are safe on architectures without efficient
> unaligned access.
> 
> Signed-off-by: Xin Xie <xiexinet@xxxxxxxxx>
>
> diff --git a/net/hsr/hsr_device.c b/net/hsr/hsr_device.c
> index 5af491ed2b72..0973f9a94f4d 100644
> --- a/net/hsr/hsr_device.c
> +++ b/net/hsr/hsr_device.c
> @@ -372,10 +372,21 @@ static void send_prp_supervision_frame(struct hsr_port *master,
>  {
>  	struct hsr_priv *hsr = master->hsr;
>  	struct hsr_sup_payload *hsr_sp;
> +	struct hsr_sup_tlv *hsr_stlv;
>  	struct hsr_sup_tag *hsr_stag;
>  	struct sk_buff *skb;
> +	bool redbox_proxy;
> +	int extra = 0;
> +
> +	redbox_proxy = hsr->redbox && master->type == HSR_PT_INTERLINK;
> +
> +	/* A proxy-announce carries a RedBox-MAC TLV and an EOT marker. */
> +	if (redbox_proxy)
> +		extra = sizeof(struct hsr_sup_tlv) +
> +			sizeof(struct hsr_sup_payload) +
> +			sizeof(struct hsr_sup_tlv);
>  
> -	skb = hsr_init_skb(master, 0);
> +	skb = hsr_init_skb(master, extra);
>  	if (!skb) {
>  		netdev_warn_once(master->dev, "PRP: Could not send supervision frame\n");
>  		return;
> @@ -393,9 +404,25 @@ static void send_prp_supervision_frame(struct hsr_port *master,
>  	hsr_stag->tlv.HSR_TLV_type = PRP_TLV_LIFE_CHECK_DD;
>  	hsr_stag->tlv.HSR_TLV_length = sizeof(struct hsr_sup_payload);
>  
> -	/* Payload: MacAddressA */
> +	/* Payload: MacAddressA, the announced node. */
>  	hsr_sp = skb_put(skb, sizeof(struct hsr_sup_payload));
> -	ether_addr_copy(hsr_sp->macaddress_A, master->dev->dev_addr);
> +	ether_addr_copy(hsr_sp->macaddress_A, addr);
> +
> +	/* Proxy-announce: append the RedBox-MAC TLV (Type 30) and an explicit
> +	 * EOT to terminate the TLV chain before zero padding.
> +	 */
> +	if (redbox_proxy) {
> +		hsr_stlv = skb_put(skb, sizeof(struct hsr_sup_tlv));
> +		hsr_stlv->HSR_TLV_type = PRP_TLV_REDBOX_MAC;
> +		hsr_stlv->HSR_TLV_length = sizeof(struct hsr_sup_payload);
> +
> +		hsr_sp = skb_put(skb, sizeof(struct hsr_sup_payload));
> +		ether_addr_copy(hsr_sp->macaddress_A, hsr->macaddress_redbox);
> +
> +		hsr_stlv = skb_put(skb, sizeof(struct hsr_sup_tlv));
> +		hsr_stlv->HSR_TLV_type = HSR_TLV_EOT;
> +		hsr_stlv->HSR_TLV_length = 0;
> +	}
>  
>  	if (skb_put_padto(skb, ETH_ZLEN)) {
>  		spin_unlock_bh(&hsr->seqnr_lock);
> diff --git a/net/hsr/hsr_framereg.c b/net/hsr/hsr_framereg.c
> index 8f708b6e6c33..b3b106be692e 100644
> --- a/net/hsr/hsr_framereg.c
> +++ b/net/hsr/hsr_framereg.c
> @@ -293,8 +293,17 @@ struct hsr_node *hsr_get_node(struct hsr_port *port, struct list_head *node_db,
>  	 */
>  	if (ethhdr->h_proto == htons(ETH_P_PRP) ||
>  	    ethhdr->h_proto == htons(ETH_P_HSR)) {
> -		/* Check if skb contains hsr_ethhdr */
> -		if (skb->mac_len < sizeof(struct hsr_ethhdr))
> +		bool prp_sup;
> +
> +		/* A PRP supervision frame is an untagged ETH_P_PRP frame
> +		 * (mac_len == ETH_HLEN); its RCT is appended only on egress.
> +		 * HSR (ETH_P_HSR) supervision is front-tagged and still must
> +		 * contain a struct hsr_ethhdr.
> +		 */
> +		prp_sup = hsr->prot_version == PRP_V1 &&
> +			  ethhdr->h_proto == htons(ETH_P_PRP) && is_sup;
> +
> +		if (!prp_sup && skb->mac_len < sizeof(struct hsr_ethhdr))
>  			return NULL;
>  	} else {
>  		rct = skb_get_PRP_rct(skb);
> diff --git a/net/hsr/hsr_main.h b/net/hsr/hsr_main.h
> index 134e4f3fff60..c27cfdd9ca3f 100644
> --- a/net/hsr/hsr_main.h
> +++ b/net/hsr/hsr_main.h
> @@ -211,7 +211,7 @@ struct hsr_priv {
>  				 */
>  	bool fwd_offloaded;	/* Forwarding offloaded to HW */
>  	bool redbox;            /* Device supports HSR RedBox */
> -	unsigned char		macaddress_redbox[ETH_ALEN];
> +	unsigned char	macaddress_redbox[ETH_ALEN] __aligned(sizeof(u16));

The indentation is wrong here, could you keep at the same level it was
before?