net: ipv6: add rpl sr tunnel

This patch adds functionality to configure routes for RPL source routing
functionality. There is no IPIP functionality yet implemented which can
be added later when the cases when to use IPv6 encapuslation comes more
clear.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: alexaring

include/net/rpl.h

@@ -11,6 +11,18 @@
 
 #include <linux/rpl.h>
 
+#if IS_ENABLED(CONFIG_IPV6_RPL_LWTUNNEL)
+extern int rpl_init(void);
+extern void rpl_exit(void);
+#else
+static inline int rpl_init(void)
+{
+	return 0;
+}
+
+static inline void rpl_exit(void) {}
+#endif
+
 /* Worst decompression memory usage ipv6 address (16) + pad 7 */
 #define IPV6_RPL_SRH_WORST_SWAP_SIZE (sizeof(struct in6_addr) + 7)
 

include/uapi/linux/lwtunnel.h

@@ -13,6 +13,7 @@ enum lwtunnel_encap_types {
 	LWTUNNEL_ENCAP_SEG6,
 	LWTUNNEL_ENCAP_BPF,
 	LWTUNNEL_ENCAP_SEG6_LOCAL,
+	LWTUNNEL_ENCAP_RPL,
 	__LWTUNNEL_ENCAP_MAX,
 };
 

include/uapi/linux/rpl_iptunnel.h

@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
+/*
+ *  IPv6 RPL-SR implementation
+ *
+ *  Author:
+ *  (C) 2020 Alexander Aring <alex.aring@gmail.com>
+ */
+
+#ifndef _UAPI_LINUX_RPL_IPTUNNEL_H
+#define _UAPI_LINUX_RPL_IPTUNNEL_H
+
+enum {
+	RPL_IPTUNNEL_UNSPEC,
+	RPL_IPTUNNEL_SRH,
+	__RPL_IPTUNNEL_MAX,
+};
+#define RPL_IPTUNNEL_MAX (__RPL_IPTUNNEL_MAX - 1)
+
+#define RPL_IPTUNNEL_SRH_SIZE(srh) (((srh)->hdrlen + 1) << 3)
+
+#endif

net/core/lwtunnel.c

@@ -41,6 +41,8 @@ static const char *lwtunnel_encap_str(enum lwtunnel_encap_types encap_type)
 		return "BPF";
 	case LWTUNNEL_ENCAP_SEG6_LOCAL:
 		return "SEG6LOCAL";
+	case LWTUNNEL_ENCAP_RPL:
+		return "RPL";
 	case LWTUNNEL_ENCAP_IP6:
 	case LWTUNNEL_ENCAP_IP:
 	case LWTUNNEL_ENCAP_NONE:

net/ipv6/Kconfig

@@ -303,4 +303,14 @@ config IPV6_SEG6_BPF
 	depends on IPV6_SEG6_LWTUNNEL
 	depends on IPV6 = y
 
+config IPV6_RPL_LWTUNNEL
+	bool "IPv6: RPL Source Routing Header support"
+	depends on IPV6
+	select LWTUNNEL
+	---help---
+	  Support for RFC6554 RPL Source Routing Header using the lightweight
+	  tunnels mechanism.
+
+	  If unsure, say N.
+
 endif # IPV6

net/ipv6/Makefile

@@ -26,6 +26,7 @@ ipv6-$(CONFIG_SYN_COOKIES) += syncookies.o
 ipv6-$(CONFIG_NETLABEL) += calipso.o
 ipv6-$(CONFIG_IPV6_SEG6_LWTUNNEL) += seg6_iptunnel.o seg6_local.o
 ipv6-$(CONFIG_IPV6_SEG6_HMAC) += seg6_hmac.o
+ipv6-$(CONFIG_IPV6_RPL_LWTUNNEL) += rpl_iptunnel.o
 
 ipv6-objs += $(ipv6-y)
 

net/ipv6/af_inet6.c

@@ -59,6 +59,7 @@
 #endif
 #include <net/calipso.h>
 #include <net/seg6.h>
+#include <net/rpl.h>
 
 #include <linux/uaccess.h>
 #include <linux/mroute6.h>
@@ -1114,6 +1115,10 @@ static int __init inet6_init(void)
 	if (err)
 		goto seg6_fail;
 
+	err = rpl_init();
+	if (err)
+		goto rpl_fail;
+
 	err = igmp6_late_init();
 	if (err)
 		goto igmp6_late_err;
@@ -1136,6 +1141,8 @@ static int __init inet6_init(void)
 	igmp6_late_cleanup();
 #endif
 igmp6_late_err:
+	rpl_exit();
+rpl_fail:
 	seg6_exit();
 seg6_fail:
 	calipso_exit();