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Message-ID: <20170805103948.21549-1-david.lebrun@uclouvain.be>
Date: Sat, 5 Aug 2017 12:39:48 +0200
From: David Lebrun <david.lebrun@...ouvain.be>
To: <netdev@...r.kernel.org>
CC: David Lebrun <david.lebrun@...ouvain.be>
Subject: [PATCH net-next v2 5/5] 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: David Lebrun <david.lebrun@...ouvain.be>
---
net/ipv6/seg6_local.c | 271 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 271 insertions(+)
diff --git a/net/ipv6/seg6_local.c b/net/ipv6/seg6_local.c
index ab1fc1b..147680e 100644
--- a/net/ipv6/seg6_local.c
+++ b/net/ipv6/seg6_local.c
@@ -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)
--
2.10.2
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