From 38ee7f2d47565689f35662d488d25e7afc43477d Mon Sep 17 00:00:00 2001 From: David Lebrun Date: Fri, 25 Aug 2017 09:56:45 +0200 Subject: [PATCH] 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: David Lebrun Signed-off-by: David S. Miller --- include/uapi/linux/seg6_iptunnel.h | 16 +++++++++++++--- net/ipv6/seg6_iptunnel.c | 25 +++++++++++++++++++++++-- 2 files changed, 36 insertions(+), 5 deletions(-) diff --git a/include/uapi/linux/seg6_iptunnel.h b/include/uapi/linux/seg6_iptunnel.h index b6e5a0a1afd7..b23df9f58354 100644 --- a/include/uapi/linux/seg6_iptunnel.h +++ b/include/uapi/linux/seg6_iptunnel.h @@ -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; - return ((tuninfo->srh->hdrlen + 1) << 3) + - (encap * sizeof(struct ipv6hdr)); + 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) + head; } #endif diff --git a/net/ipv6/seg6_iptunnel.c b/net/ipv6/seg6_iptunnel.c index 5bec7817a7b9..bd6cc688bd19 100644 --- a/net/ipv6/seg6_iptunnel.c +++ b/net/ipv6/seg6_iptunnel.c @@ -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;