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Commit 140f04c3 authored by David Lebrun's avatar David Lebrun Committed by David S. Miller
Browse files

ipv6: sr: implement several seg6local actions 



This patch implements the following seg6local actions.

- SEG6_LOCAL_ACTION_END: regular SRH processing. The DA of the packet
  is updated to the next segment and forwarded accordingly.

- SEG6_LOCAL_ACTION_END_X: same as above, except that the packet is
  forwarded to the specified IPv6 next-hop.

- SEG6_LOCAL_ACTION_END_DX6: decapsulate the packet and forward to
  inner IPv6 packet to the specified IPv6 next-hop.

- SEG6_LOCAL_ACTION_END_B6: insert the specified SRH directly after
  the IPv6 header of the packet.

- SEG6_LOCAL_ACTION_END_B6_ENCAP: encapsulate the packet within
  an outer IPv6 header, containing the specified SRH.

Signed-off-by: default avatarDavid Lebrun <david.lebrun@uclouvain.be>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2d9cc60a

net/ipv6/seg6_local.c

+271 −0
Original line number Diff line number Diff line
@@ -58,11 +58,282 @@ static struct seg6_local_lwt *seg6_local_lwtunnel(struct lwtunnel_state *lwt) 
	return (struct seg6_local_lwt *)lwt->data;

}



static struct ipv6_sr_hdr *get_srh(struct sk_buff *skb)

{

	struct ipv6_sr_hdr *srh;

	struct ipv6hdr *hdr;

	int len;



	hdr = ipv6_hdr(skb);

	if (hdr->nexthdr != IPPROTO_ROUTING)

		return NULL;



	srh = (struct ipv6_sr_hdr *)(hdr + 1);

	len = (srh->hdrlen + 1) << 3;



	if (!pskb_may_pull(skb, sizeof(*hdr) + len))

		return NULL;



	if (!seg6_validate_srh(srh, len))

		return NULL;



	return srh;

}



static struct ipv6_sr_hdr *get_and_validate_srh(struct sk_buff *skb)

{

	struct ipv6_sr_hdr *srh;



	srh = get_srh(skb);

	if (!srh)

		return NULL;



	if (srh->segments_left == 0)

		return NULL;



#ifdef CONFIG_IPV6_SEG6_HMAC

	if (!seg6_hmac_validate_skb(skb))

		return NULL;

#endif



	return srh;

}



/* regular endpoint function */

static int input_action_end(struct sk_buff *skb, struct seg6_local_lwt *slwt)

{

	struct ipv6_sr_hdr *srh;

	struct in6_addr *addr;



	srh = get_and_validate_srh(skb);

	if (!srh)

		goto drop;



	srh->segments_left--;

	addr = srh->segments + srh->segments_left;



	ipv6_hdr(skb)->daddr = *addr;



	skb_dst_drop(skb);

	ip6_route_input(skb);



	return dst_input(skb);



drop:

	kfree_skb(skb);

	return -EINVAL;

}



/* regular endpoint, and forward to specified nexthop */

static int input_action_end_x(struct sk_buff *skb, struct seg6_local_lwt *slwt)

{

	struct net *net = dev_net(skb->dev);

	struct ipv6_sr_hdr *srh;

	struct dst_entry *dst;

	struct in6_addr *addr;

	struct ipv6hdr *hdr;

	struct flowi6 fl6;

	int flags;



	srh = get_and_validate_srh(skb);

	if (!srh)

		goto drop;



	srh->segments_left--;

	addr = srh->segments + srh->segments_left;



	hdr = ipv6_hdr(skb);

	hdr->daddr = *addr;



	skb_dst_drop(skb);



	fl6.flowi6_iif = skb->dev->ifindex;

	fl6.daddr = slwt->nh6;

	fl6.saddr = hdr->saddr;

	fl6.flowlabel = ip6_flowinfo(hdr);

	fl6.flowi6_mark = skb->mark;

	fl6.flowi6_proto = hdr->nexthdr;



	flags = RT6_LOOKUP_F_HAS_SADDR | RT6_LOOKUP_F_IFACE |

		RT6_LOOKUP_F_REACHABLE;



	dst = ip6_route_input_lookup(net, skb->dev, &fl6, flags);

	if (dst->dev->flags & IFF_LOOPBACK)

		goto drop;



	skb_dst_set(skb, dst);



	return dst_input(skb);



drop:

	kfree_skb(skb);

	return -EINVAL;

}



/* decapsulate and forward to specified nexthop */

static int input_action_end_dx6(struct sk_buff *skb,

				struct seg6_local_lwt *slwt)

{

	struct net *net = dev_net(skb->dev);

	struct ipv6hdr *inner_hdr;

	struct ipv6_sr_hdr *srh;

	struct dst_entry *dst;

	unsigned int off = 0;

	struct flowi6 fl6;

	bool use_nh;

	int flags;



	/* this function accepts IPv6 encapsulated packets, with either

	 * an SRH with SL=0, or no SRH.

	 */



	srh = get_srh(skb);

	if (srh && srh->segments_left > 0)

		goto drop;



#ifdef CONFIG_IPV6_SEG6_HMAC

	if (srh && !seg6_hmac_validate_skb(skb))

		goto drop;

#endif



	if (ipv6_find_hdr(skb, &off, IPPROTO_IPV6, NULL, NULL) < 0)

		goto drop;



	if (!pskb_pull(skb, off))

		goto drop;



	skb_postpull_rcsum(skb, skb_network_header(skb), off);



	skb_reset_network_header(skb);

	skb_reset_transport_header(skb);

	skb->encapsulation = 0;



	inner_hdr = ipv6_hdr(skb);



	/* The inner packet is not associated to any local interface,

	 * so we do not call netif_rx().

	 *

	 * If slwt->nh6 is set to ::, then lookup the nexthop for the

	 * inner packet's DA. Otherwise, use the specified nexthop.

	 */



	use_nh = !ipv6_addr_any(&slwt->nh6);



	skb_dst_drop(skb);



	fl6.flowi6_iif = skb->dev->ifindex;

	fl6.daddr = use_nh ? slwt->nh6 : inner_hdr->daddr;

	fl6.saddr = inner_hdr->saddr;

	fl6.flowlabel = ip6_flowinfo(inner_hdr);

	fl6.flowi6_mark = skb->mark;

	fl6.flowi6_proto = inner_hdr->nexthdr;



	flags = RT6_LOOKUP_F_HAS_SADDR | RT6_LOOKUP_F_REACHABLE;

	if (use_nh)

		flags |= RT6_LOOKUP_F_IFACE;



	dst = ip6_route_input_lookup(net, skb->dev, &fl6, flags);

	if (dst->dev->flags & IFF_LOOPBACK)

		goto drop;



	skb_dst_set(skb, dst);



	return dst_input(skb);

drop:

	kfree_skb(skb);

	return -EINVAL;

}



/* push an SRH on top of the current one */

static int input_action_end_b6(struct sk_buff *skb, struct seg6_local_lwt *slwt)

{

	struct ipv6_sr_hdr *srh;

	int err = -EINVAL;



	srh = get_and_validate_srh(skb);

	if (!srh)

		goto drop;



	err = seg6_do_srh_inline(skb, slwt->srh);

	if (err)

		goto drop;



	ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));

	skb_set_transport_header(skb, sizeof(struct ipv6hdr));



	skb_dst_drop(skb);

	ip6_route_input(skb);



	return dst_input(skb);



drop:

	kfree_skb(skb);

	return err;

}



/* encapsulate within an outer IPv6 header and a specified SRH */

static int input_action_end_b6_encap(struct sk_buff *skb,

				     struct seg6_local_lwt *slwt)

{

	struct ipv6_sr_hdr *srh;

	struct in6_addr *addr;

	int err = -EINVAL;



	srh = get_and_validate_srh(skb);

	if (!srh)

		goto drop;



	srh->segments_left--;

	addr = srh->segments + srh->segments_left;

	ipv6_hdr(skb)->daddr = *addr;



	skb_reset_inner_headers(skb);

	skb->encapsulation = 1;



	err = seg6_do_srh_encap(skb, slwt->srh);

	if (err)

		goto drop;



	ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));

	skb_set_transport_header(skb, sizeof(struct ipv6hdr));



	skb_dst_drop(skb);

	ip6_route_input(skb);



	return dst_input(skb);



drop:

	kfree_skb(skb);

	return err;

}



static struct seg6_action_desc seg6_action_table[] = {

	{

		.action		= SEG6_LOCAL_ACTION_END,

		.attrs		= 0,

		.input		= input_action_end,

	},

	{

		.action		= SEG6_LOCAL_ACTION_END_X,

		.attrs		= (1 << SEG6_LOCAL_NH6),

		.input		= input_action_end_x,

	},

	{

		.action		= SEG6_LOCAL_ACTION_END_DX6,

		.attrs		= (1 << SEG6_LOCAL_NH6),

		.input		= input_action_end_dx6,

	},

	{

		.action		= SEG6_LOCAL_ACTION_END_B6,

		.attrs		= (1 << SEG6_LOCAL_SRH),

		.input		= input_action_end_b6,

	},

	{

		.action		= SEG6_LOCAL_ACTION_END_B6_ENCAP,

		.attrs		= (1 << SEG6_LOCAL_SRH),

		.input		= input_action_end_b6_encap,

		.static_headroom	= sizeof(struct ipv6hdr),

	}

};



static struct seg6_action_desc *__get_action_desc(int action)