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: David Lebrun <david.leb...@uclouvain.be> --- include/uapi/linux/seg6_iptunnel.h | 19 +++++++++++++++---- net/ipv6/seg6_iptunnel.c | 18 ++++++++++++++++++ 2 files changed, 33 insertions(+), 4 deletions(-) diff --git a/include/uapi/linux/seg6_iptunnel.h b/include/uapi/linux/seg6_iptunnel.h index b6e5a0a..63f0fe4 100644 --- a/include/uapi/linux/seg6_iptunnel.h +++ b/include/uapi/linux/seg6_iptunnel.h @@ -33,16 +33,27 @@ 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); - - return ((tuninfo->srh->hdrlen + 1) << 3) + - (encap * sizeof(struct ipv6hdr)); + 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: + head = sizeof(struct ipv6hdr) + 14; + break; + } + + return ((tuninfo->srh->hdrlen + 1) << 3) + head; } #endif diff --git a/net/ipv6/seg6_iptunnel.c b/net/ipv6/seg6_iptunnel.c index 5bec781..93aa322 100644 --- a/net/ipv6/seg6_iptunnel.c +++ b/net/ipv6/seg6_iptunnel.c @@ -240,6 +240,22 @@ static int seg6_do_srh(struct sk_buff *skb) 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; } ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); @@ -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; } -- 2.10.2
