From 6c8702c60b88651072460f3f4026c7dfe2521d12 Mon Sep 17 00:00:00 2001 From: David Lebrun Date: Tue, 8 Nov 2016 14:57:41 +0100 Subject: ipv6: sr: add support for SRH encapsulation and injection with lwtunnels This patch creates a new type of interfaceless lightweight tunnel (SEG6), enabling the encapsulation and injection of SRH within locally emitted packets and forwarded packets. >From a configuration viewpoint, a seg6 tunnel would be configured as follows: ip -6 ro ad fc00::1/128 encap seg6 mode encap segs fc42::1,fc42::2,fc42::3 dev eth0 Any packet whose destination address is fc00::1 would thus be encapsulated within an outer IPv6 header containing the SRH with three segments, and would actually be routed to the first segment of the list. If `mode inline' was specified instead of `mode encap', then the SRH would be directly inserted after the IPv6 header without outer encapsulation. The inline mode is only available if CONFIG_IPV6_SEG6_INLINE is enabled. This feature was made configurable because direct header insertion may break several mechanisms such as PMTUD or IPSec AH. Signed-off-by: David Lebrun Signed-off-by: David S. Miller --- net/ipv6/seg6.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) (limited to 'net/ipv6/seg6.c') diff --git a/net/ipv6/seg6.c b/net/ipv6/seg6.c index e246b0ba12ac..9c78053e67e0 100644 --- a/net/ipv6/seg6.c +++ b/net/ipv6/seg6.c @@ -26,6 +26,43 @@ #include #include +bool seg6_validate_srh(struct ipv6_sr_hdr *srh, int len) +{ + int trailing; + unsigned int tlv_offset; + + if (srh->type != IPV6_SRCRT_TYPE_4) + return false; + + if (((srh->hdrlen + 1) << 3) != len) + return false; + + if (srh->segments_left != srh->first_segment) + return false; + + tlv_offset = sizeof(*srh) + ((srh->first_segment + 1) << 4); + + trailing = len - tlv_offset; + if (trailing < 0) + return false; + + while (trailing) { + struct sr6_tlv *tlv; + unsigned int tlv_len; + + tlv = (struct sr6_tlv *)((unsigned char *)srh + tlv_offset); + tlv_len = sizeof(*tlv) + tlv->len; + + trailing -= tlv_len; + if (trailing < 0) + return false; + + tlv_offset += tlv_len; + } + + return true; +} + static struct genl_family seg6_genl_family; static const struct nla_policy seg6_genl_policy[SEG6_ATTR_MAX + 1] = { @@ -198,10 +235,16 @@ int __init seg6_init(void) if (err) goto out_unregister_genl; + err = seg6_iptunnel_init(); + if (err) + goto out_unregister_pernet; + pr_info("Segment Routing with IPv6\n"); out: return err; +out_unregister_pernet: + unregister_pernet_subsys(&ip6_segments_ops); out_unregister_genl: genl_unregister_family(&seg6_genl_family); goto out; @@ -209,6 +252,7 @@ out_unregister_genl: void seg6_exit(void) { + seg6_iptunnel_exit(); unregister_pernet_subsys(&ip6_segments_ops); genl_unregister_family(&seg6_genl_family); } -- cgit v1.2.3