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Commit 38ee7f2d authored by David Lebrun's avatar David Lebrun Committed by David S. Miller
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ipv6: sr: add support for encapsulation of L2 frames 

This patch implements the L2 frame encapsulation mechanism, referred to
as T.Encaps.L2 in the SRv6 specifications [1].

A new type of SRv6 tunnel mode is added (SEG6_IPTUN_MODE_L2ENCAP). It only
accepts packets with an existing MAC header (i.e., it will not work for
locally generated packets). The resulting packet looks like IPv6 -> SRH ->
Ethernet -> original L3 payload. The next header field of the SRH is set to
NEXTHDR_NONE.

[1] https://tools.ietf.org/html/draft-filsfils-spring-srv6-network-programming-01



Signed-off-by: default avatarDavid Lebrun <david.lebrun@uclouvain.be>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 32d99d0b

include/uapi/linux/seg6_iptunnel.h

+14 −4
Original line number Diff line number Diff line
@@ -33,16 +33,26 @@ struct seg6_iptunnel_encap { 
enum {

	SEG6_IPTUN_MODE_INLINE,

	SEG6_IPTUN_MODE_ENCAP,

	SEG6_IPTUN_MODE_L2ENCAP,

};



#ifdef __KERNEL__



static inline size_t seg6_lwt_headroom(struct seg6_iptunnel_encap *tuninfo)

{

	int encap = (tuninfo->mode == SEG6_IPTUN_MODE_ENCAP);

	int head = 0;



	switch (tuninfo->mode) {

	case SEG6_IPTUN_MODE_INLINE:

		break;

	case SEG6_IPTUN_MODE_ENCAP:

		head = sizeof(struct ipv6hdr);

		break;

	case SEG6_IPTUN_MODE_L2ENCAP:

		return 0;

	}



	return ((tuninfo->srh->hdrlen + 1) << 3) +

	       (encap * sizeof(struct ipv6hdr));

	return ((tuninfo->srh->hdrlen + 1) << 3) + head;

}



#endif

net/ipv6/seg6_iptunnel.c

+23 −2
Original line number Diff line number Diff line
@@ -238,6 +238,22 @@ static int seg6_do_srh(struct sk_buff *skb) 
		if (err)

			return err;



		skb->protocol = htons(ETH_P_IPV6);

		break;

	case SEG6_IPTUN_MODE_L2ENCAP:

		if (!skb_mac_header_was_set(skb))

			return -EINVAL;



		if (pskb_expand_head(skb, skb->mac_len, 0, GFP_ATOMIC) < 0)

			return -ENOMEM;



		skb_mac_header_rebuild(skb);

		skb_push(skb, skb->mac_len);



		err = seg6_do_srh_encap(skb, tinfo->srh, NEXTHDR_NONE);

		if (err)

			return err;



		skb->protocol = htons(ETH_P_IPV6);

		break;

	}
@@ -386,6 +402,8 @@ static int seg6_build_state(struct nlattr *nla, 
		break;

	case SEG6_IPTUN_MODE_ENCAP:

		break;

	case SEG6_IPTUN_MODE_L2ENCAP:

		break;

	default:

		return -EINVAL;

	}
@@ -409,8 +427,11 @@ static int seg6_build_state(struct nlattr *nla, 
	memcpy(&slwt->tuninfo, tuninfo, tuninfo_len);



	newts->type = LWTUNNEL_ENCAP_SEG6;

	newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT |

			LWTUNNEL_STATE_INPUT_REDIRECT;

	newts->flags |= LWTUNNEL_STATE_INPUT_REDIRECT;



	if (tuninfo->mode != SEG6_IPTUN_MODE_L2ENCAP)

		newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT;



	newts->headroom = seg6_lwt_headroom(tuninfo);



	*ts = newts;