Subject: Re: [PATCH v2 net-next] macvlan: Add nodst option to macvlan type source

From: Leon Romanovsky <[email-masked]>
Date: Sun, 25 Apr 2021 14:12:16 +0300

On Sun, Apr 25, 2021 at 11:22:03AM +0200, Jethro Beekman wrote:
> The default behavior for source MACVLAN is to duplicate packets to
> appropriate type source devices, and then do the normal destination MACVLAN
> flow. This patch adds an option to skip destination MACVLAN processing if
> any matching source MACVLAN device has the option set.
> 
> This allows setting up a "catch all" device for source MACVLAN: create one
> or more devices with type source nodst, and one device with e.g. type vepa,
> and incoming traffic will be received on exactly one device.
> 
> v2: netdev wants non-standard line length

Can you please put the changelog after "---"? So it won't be part of
commit message in the git log.

Thanks

> 
> Signed-off-by: Jethro Beekman <[email-masked]>
> ---
>  drivers/net/macvlan.c        | 19 ++++++++++++++-----
>  include/uapi/linux/if_link.h |  1 +
>  2 files changed, 15 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
> index 9a9a5cf36a4b..7427b989607e 100644
> --- a/drivers/net/macvlan.c
> +++ b/drivers/net/macvlan.c
> @@ -423,18 +423,24 @@ static void macvlan_forward_source_one(struct sk_buff *skb,
>  	macvlan_count_rx(vlan, len, ret == NET_RX_SUCCESS, false);
>  }
>  
> -static void macvlan_forward_source(struct sk_buff *skb,
> +static bool macvlan_forward_source(struct sk_buff *skb,
>  				   struct macvlan_port *port,
>  				   const unsigned char *addr)
>  {
>  	struct macvlan_source_entry *entry;
>  	u32 idx = macvlan_eth_hash(addr);
>  	struct hlist_head *h = &port->vlan_source_hash[idx];
> +	bool consume = false;
>  
>  	hlist_for_each_entry_rcu(entry, h, hlist) {
> -		if (ether_addr_equal_64bits(entry->addr, addr))
> +		if (ether_addr_equal_64bits(entry->addr, addr)) {
> +			if (entry->vlan->flags & MACVLAN_FLAG_NODST)
> +				consume = true;
>  			macvlan_forward_source_one(skb, entry->vlan);
> +		}
>  	}
> +
> +	return consume;
>  }
>  
>  /* called under rcu_read_lock() from netif_receive_skb */
> @@ -463,7 +469,8 @@ static rx_handler_result_t macvlan_handle_frame(struct sk_buff **pskb)
>  			return RX_HANDLER_CONSUMED;
>  		*pskb = skb;
>  		eth = eth_hdr(skb);
> -		macvlan_forward_source(skb, port, eth->h_source);
> +		if (macvlan_forward_source(skb, port, eth->h_source))
> +			return RX_HANDLER_CONSUMED;
>  		src = macvlan_hash_lookup(port, eth->h_source);
>  		if (src && src->mode != MACVLAN_MODE_VEPA &&
>  		    src->mode != MACVLAN_MODE_BRIDGE) {
> @@ -482,7 +489,8 @@ static rx_handler_result_t macvlan_handle_frame(struct sk_buff **pskb)
>  		return RX_HANDLER_PASS;
>  	}
>  
> -	macvlan_forward_source(skb, port, eth->h_source);
> +	if (macvlan_forward_source(skb, port, eth->h_source))
> +		return RX_HANDLER_CONSUMED;
>  	if (macvlan_passthru(port))
>  		vlan = list_first_or_null_rcu(&port->vlans,
>  					      struct macvlan_dev, list);
> @@ -1286,7 +1294,8 @@ static int macvlan_validate(struct nlattr *tb[], struct nlattr *data[],
>  		return 0;
>  
>  	if (data[IFLA_MACVLAN_FLAGS] &&
> -	    nla_get_u16(data[IFLA_MACVLAN_FLAGS]) & ~MACVLAN_FLAG_NOPROMISC)
> +	    nla_get_u16(data[IFLA_MACVLAN_FLAGS]) & ~(MACVLAN_FLAG_NOPROMISC |
> +						      MACVLAN_FLAG_NODST))
>  		return -EINVAL;
>  
>  	if (data[IFLA_MACVLAN_MODE]) {
> diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
> index 91c8dda6d95d..cd5b382a4138 100644
> --- a/include/uapi/linux/if_link.h
> +++ b/include/uapi/linux/if_link.h
> @@ -614,6 +614,7 @@ enum macvlan_macaddr_mode {
>  };
>  
>  #define MACVLAN_FLAG_NOPROMISC	1
> +#define MACVLAN_FLAG_NODST	2 /* skip dst macvlan if matching src macvlan */
>  
>  /* VRF section */
>  enum {
> -- 
> 2.31.1
>