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 <david.lebrun@uclouvain.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/uapi/linux/seg6_iptunnel.h b/include/uapi/linux/seg6_iptunnel.h
new file mode 100644
index 0000000..0f7dbd2
--- /dev/null
+++ b/include/uapi/linux/seg6_iptunnel.h
@@ -0,0 +1,44 @@
+/*
+ * SR-IPv6 implementation
+ *
+ * Author:
+ * David Lebrun <david.lebrun@uclouvain.be>
+ *
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _UAPI_LINUX_SEG6_IPTUNNEL_H
+#define _UAPI_LINUX_SEG6_IPTUNNEL_H
+
+enum {
+ SEG6_IPTUNNEL_UNSPEC,
+ SEG6_IPTUNNEL_SRH,
+ __SEG6_IPTUNNEL_MAX,
+};
+#define SEG6_IPTUNNEL_MAX (__SEG6_IPTUNNEL_MAX - 1)
+
+struct seg6_iptunnel_encap {
+ int mode;
+ struct ipv6_sr_hdr srh[0];
+};
+
+#define SEG6_IPTUN_ENCAP_SIZE(x) ((sizeof(*x)) + (((x)->srh->hdrlen + 1) << 3))
+
+enum {
+ SEG6_IPTUN_MODE_INLINE,
+ SEG6_IPTUN_MODE_ENCAP,
+};
+
+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));
+}
+
+#endif