[PATCH RFC iproute2-next 0/2] seg6: add support for the SRv6 End.MAP behavior

[PATCH RFC iproute2-next 0/2] seg6: add support for the SRv6 End.MAP behavior

[Yuya Kusakabe]

This series adds support for the "seg6mobile" lightweight tunnel, the
iproute2 counterpart of the SRv6 Mobile User Plane (RFC 9433) kernel
RFC series [1], starting with the End.MAP behavior.

Patch 1 imports the new UAPI headers as a standalone patch so it can
be dropped once the matching kernel header lands.  The selftest in
the kernel series needs the "seg6mobile" keyword to run.

[1] https://lore.kernel.org/netdev/20260710-seg6-mobile-end-map-v1-0-99be02d68143@gmail.com/

Signed-off-by: Yuya Kusakabe <yuya.kusakabe@gmail.com>
---
Yuya Kusakabe (2):
      uapi: sync lwtunnel.h and add seg6_mobile.h
      seg6: add support for the End.MAP behavior under seg6mobile encap

 include/uapi/linux/lwtunnel.h    |   1 +
 include/uapi/linux/seg6_mobile.h |  58 +++++++++++++
 ip/iproute.c                     |   6 +-
 ip/iproute_lwtunnel.c            | 173 +++++++++++++++++++++++++++++++++++++++
 man/man8/ip-route.8.in           |  24 ++++++
 5 files changed, 260 insertions(+), 2 deletions(-)
---
base-commit: 37c491d82cebef070173878e167076a1956dcd92
change-id: 20260523-seg6-mobile-end-map-6f5560bfb68e

Best regards,
--  
Yuya Kusakabe <yuya.kusakabe@gmail.com>

[PATCH RFC iproute2-next 1/2] uapi: sync lwtunnel.h and add seg6_mobile.h

[Yuya Kusakabe]

Signed-off-by: Yuya Kusakabe <yuya.kusakabe@gmail.com>
---
 include/uapi/linux/lwtunnel.h    |  1 +
 include/uapi/linux/seg6_mobile.h | 58 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 59 insertions(+)

diff --git a/include/uapi/linux/lwtunnel.h b/include/uapi/linux/lwtunnel.h
index 9d22961be619..b5adca10a9f1 100644
--- a/include/uapi/linux/lwtunnel.h
+++ b/include/uapi/linux/lwtunnel.h
@@ -16,6 +16,7 @@ enum lwtunnel_encap_types {
 	LWTUNNEL_ENCAP_RPL,
 	LWTUNNEL_ENCAP_IOAM6,
 	LWTUNNEL_ENCAP_XFRM,
+	LWTUNNEL_ENCAP_SEG6_MOBILE,
 	__LWTUNNEL_ENCAP_MAX,
 };
 
diff --git a/include/uapi/linux/seg6_mobile.h b/include/uapi/linux/seg6_mobile.h
new file mode 100644
index 000000000000..b99eabe9a2a1
--- /dev/null
+++ b/include/uapi/linux/seg6_mobile.h
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ *  SRv6 Mobile User Plane implementation
+ */
+#ifndef _LINUX_SEG6_MOBILE_H
+#define _LINUX_SEG6_MOBILE_H
+
+enum {
+	SEG6_MOBILE_UNSPEC,
+	SEG6_MOBILE_ACTION,
+	SEG6_MOBILE_NH6,
+	SEG6_MOBILE_COUNTERS,
+	__SEG6_MOBILE_MAX,
+};
+
+#define SEG6_MOBILE_MAX	(__SEG6_MOBILE_MAX - 1)
+
+enum {
+	SEG6_MOBILE_ACTION_UNSPEC	= 0,
+	/* swap IPv6 DA with the next SID, leave SRH untouched */
+	SEG6_MOBILE_ACTION_END_MAP	= 1,
+
+	__SEG6_MOBILE_ACTION_MAX,
+};
+
+#define SEG6_MOBILE_ACTION_MAX	(__SEG6_MOBILE_ACTION_MAX - 1)
+
+/* SRv6 Mobile Behavior counters are encoded as netlink attributes
+ * guaranteeing the correct alignment.
+ * Each counter is identified by a different attribute type (i.e.
+ * SEG6_MOBILE_CNT_PACKETS).
+ *
+ * - SEG6_MOBILE_CNT_PACKETS: identifies a counter that counts the number
+ *   of packets that have been CORRECTLY processed by an SRv6 Behavior
+ *   instance (i.e., packets that generate errors or are dropped are NOT
+ *   counted).
+ *
+ * - SEG6_MOBILE_CNT_BYTES: identifies a counter that counts the total
+ *   amount of traffic in bytes of all packets that have been CORRECTLY
+ *   processed by an SRv6 Behavior instance (i.e., packets that generate
+ *   errors or are dropped are NOT counted).
+ *
+ * - SEG6_MOBILE_CNT_ERRORS: identifies a counter that counts the number
+ *   of packets that have NOT been properly processed by an SRv6 Behavior
+ *   instance (i.e., packets that generate errors or are dropped).
+ */
+enum {
+	SEG6_MOBILE_CNT_UNSPEC,
+	SEG6_MOBILE_CNT_PACKETS,
+	SEG6_MOBILE_CNT_BYTES,
+	SEG6_MOBILE_CNT_ERRORS,
+	SEG6_MOBILE_CNT_PAD,		/* pad for 64 bits values */
+	__SEG6_MOBILE_CNT_MAX,
+};
+
+#define SEG6_MOBILE_CNT_MAX	(__SEG6_MOBILE_CNT_MAX - 1)
+
+#endif /* _LINUX_SEG6_MOBILE_H */

-- 
2.50.1

[PATCH RFC iproute2-next 2/2] seg6: add support for the End.MAP behavior under seg6mobile encap

[Yuya Kusakabe]

Wire up a new "seg6mobile" lightweight tunnel encap type that mirrors
the kernel's LWTUNNEL_ENCAP_SEG6_MOBILE namespace, and add parse and
print support for the first RFC 9433 behavior it carries: End.MAP.

    $ ip -6 route add 2001:db8:f::/64 \
        encap seg6mobile action End.MAP nh6 2001:db8:2::e dev eth0

    $ ip -6 route show 2001:db8:f::/64
    2001:db8:f::/64  encap seg6mobile action End.MAP nh6 2001:db8:2::e dev eth0 metric 1024 pref medium

Signed-off-by: Yuya Kusakabe <yuya.kusakabe@gmail.com>
---
 ip/iproute.c           |   6 +-
 ip/iproute_lwtunnel.c  | 173 +++++++++++++++++++++++++++++++++++++++++++++++++
 man/man8/ip-route.8.in |  24 +++++++
 3 files changed, 201 insertions(+), 2 deletions(-)

diff --git a/ip/iproute.c b/ip/iproute.c
index 5b9e7ac1134a..659ebfa1b113 100644
--- a/ip/iproute.c
+++ b/ip/iproute.c
@@ -98,8 +98,8 @@ static void usage(void)
 		"TIME := NUMBER[s|ms]\n"
 		"BOOL := [1|0]\n"
 		"FEATURES := ecn\n"
-		"ENCAPTYPE := [ mpls | ip | ip6 | seg6 | seg6local | rpl | ioam6 | xfrm ]\n"
-		"ENCAPHDR := [ MPLSLABEL | SEG6HDR | SEG6LOCAL | IOAM6HDR | XFRMINFO ]\n"
+		"ENCAPTYPE := [ mpls | ip | ip6 | seg6 | seg6local | seg6mobile | rpl | ioam6 | xfrm ]\n"
+		"ENCAPHDR := [ MPLSLABEL | SEG6HDR | SEG6LOCAL | SEG6MOBILE | IOAM6HDR | XFRMINFO ]\n"
 		"SEG6HDR := [ mode SEGMODE ] segs ADDR1,ADDRi,ADDRn [hmac HMACKEYID] [cleanup]\n"
 		"SEGMODE := [ encap | encap.red | inline | l2encap | l2encap.red ]\n"
 		"SEG6LOCAL := action ACTION [ OPTIONS ] [ count ]\n"
@@ -111,6 +111,8 @@ static void usage(void)
 		"            table TABLEID | vrftable TABLEID | endpoint PROGNAME }\n"
 		"FLAVORS := { FLAVOR[,FLAVOR] }\n"
 		"FLAVOR := { psp | usp | usd | next-csid }\n"
+		"SEG6MOBILE := action MOBILE_ACTION nh6 ADDR [ count ]\n"
+		"MOBILE_ACTION := { End.MAP }\n"
 		"IOAM6HDR := trace prealloc type IOAM6_TRACE_TYPE ns IOAM6_NAMESPACE size IOAM6_TRACE_SIZE\n"
 		"XFRMINFO := if_id IF_ID [ link_dev LINK ]\n"
 		"ROUTE_GET_FLAGS := ROUTE_GET_FLAG [ ROUTE_GET_FLAGS ]\n"
diff --git a/ip/iproute_lwtunnel.c b/ip/iproute_lwtunnel.c
index 00b4f7565be6..53df6e2d7610 100644
--- a/ip/iproute_lwtunnel.c
+++ b/ip/iproute_lwtunnel.c
@@ -28,6 +28,7 @@
 #include <linux/rpl_iptunnel.h>
 #include <linux/seg6_hmac.h>
 #include <linux/seg6_local.h>
+#include <linux/seg6_mobile.h>
 #include <linux/if_tunnel.h>
 #include <linux/ioam6.h>
 #include <linux/ioam6_iptunnel.h>
@@ -55,6 +56,8 @@ static const char *format_encap_type(uint16_t type)
 		return "ioam6";
 	case LWTUNNEL_ENCAP_XFRM:
 		return "xfrm";
+	case LWTUNNEL_ENCAP_SEG6_MOBILE:
+		return "seg6mobile";
 	default:
 		return "unknown";
 	}
@@ -95,6 +98,8 @@ static uint16_t read_encap_type(const char *name)
 		return LWTUNNEL_ENCAP_IOAM6;
 	else if (strcmp(name, "xfrm") == 0)
 		return LWTUNNEL_ENCAP_XFRM;
+	else if (strcmp(name, "seg6mobile") == 0)
+		return LWTUNNEL_ENCAP_SEG6_MOBILE;
 	else if (strcmp(name, "help") == 0)
 		encap_type_usage();
 
@@ -578,6 +583,91 @@ static void print_encap_seg6local(FILE *fp, struct rtattr *encap)
 		print_seg6_local_flavors(fp, tb[SEG6_LOCAL_FLAVORS]);
 }
 
+static const char *seg6_mobile_action_names[SEG6_MOBILE_ACTION_MAX + 1] = {
+	[SEG6_MOBILE_ACTION_END_MAP]	= "End.MAP",
+};
+
+static const char *format_seg6_mobile_action(int action)
+{
+	if (action < 0 || action > SEG6_MOBILE_ACTION_MAX)
+		return "<invalid>";
+
+	return seg6_mobile_action_names[action] ?: "<unknown>";
+}
+
+static int read_seg6_mobile_action(const char *name)
+{
+	int i;
+
+	for (i = 0; i < SEG6_MOBILE_ACTION_MAX + 1; i++) {
+		if (!seg6_mobile_action_names[i])
+			continue;
+
+		if (strcmp(seg6_mobile_action_names[i], name) == 0)
+			return i;
+	}
+
+	return SEG6_MOBILE_ACTION_UNSPEC;
+}
+
+static void print_seg6_mobile_counters(FILE *fp, struct rtattr *encap)
+{
+	struct rtattr *tb[SEG6_MOBILE_CNT_MAX + 1];
+	__u64 packets = 0, bytes = 0, errors = 0;
+
+	parse_rtattr_nested(tb, SEG6_MOBILE_CNT_MAX, encap);
+
+	if (tb[SEG6_MOBILE_CNT_PACKETS])
+		packets = rta_getattr_u64(tb[SEG6_MOBILE_CNT_PACKETS]);
+
+	if (tb[SEG6_MOBILE_CNT_BYTES])
+		bytes = rta_getattr_u64(tb[SEG6_MOBILE_CNT_BYTES]);
+
+	if (tb[SEG6_MOBILE_CNT_ERRORS])
+		errors = rta_getattr_u64(tb[SEG6_MOBILE_CNT_ERRORS]);
+
+	if (is_json_context()) {
+		open_json_object("stats64");
+
+		print_u64(PRINT_JSON, "packets", NULL, packets);
+		print_u64(PRINT_JSON, "bytes", NULL, bytes);
+		print_u64(PRINT_JSON, "errors", NULL, errors);
+
+		close_json_object();
+	} else {
+		print_string(PRINT_FP, NULL, "%s ", "packets");
+		print_num(fp, 1, packets);
+
+		print_string(PRINT_FP, NULL, "%s ", "bytes");
+		print_num(fp, 1, bytes);
+
+		print_string(PRINT_FP, NULL, "%s ", "errors");
+		print_num(fp, 1, errors);
+	}
+}
+
+static void print_encap_seg6mobile(FILE *fp, struct rtattr *encap)
+{
+	struct rtattr *tb[SEG6_MOBILE_MAX + 1];
+	int action;
+
+	parse_rtattr_nested(tb, SEG6_MOBILE_MAX, encap);
+
+	if (!tb[SEG6_MOBILE_ACTION])
+		return;
+
+	action = rta_getattr_u32(tb[SEG6_MOBILE_ACTION]);
+	print_string(PRINT_ANY, "action",
+		     "action %s ", format_seg6_mobile_action(action));
+
+	if (tb[SEG6_MOBILE_NH6])
+		print_string(PRINT_ANY, "nh6", "nh6 %s ",
+			     rt_addr_n2a_rta(AF_INET6, tb[SEG6_MOBILE_NH6]));
+
+	if (tb[SEG6_MOBILE_COUNTERS] && show_stats)
+		print_seg6_mobile_counters(fp, tb[SEG6_MOBILE_COUNTERS]);
+}
+
 static void print_encap_mpls(FILE *fp, struct rtattr *encap)
 {
 	struct rtattr *tb[MPLS_IPTUNNEL_MAX+1];
@@ -893,6 +983,9 @@ void lwt_print_encap(FILE *fp, struct rtattr *encap_type,
 	case LWTUNNEL_ENCAP_XFRM:
 		print_encap_xfrm(fp, encap);
 		break;
+	case LWTUNNEL_ENCAP_SEG6_MOBILE:
+		print_encap_seg6mobile(fp, encap);
+		break;
 	}
 	close_json_object();
 }
@@ -1587,6 +1680,83 @@ static int parse_encap_seg6local(struct rtattr *rta, size_t len, int *argcp,
 	return ret;
 }
 
+/* counters are always initialized to zero by the kernel, so no value
+ * is parsed from the command line -- "count" is a bare keyword.
+ */
+static int seg6mobile_fill_counters(struct rtattr *rta, size_t len, int attr)
+{
+	struct rtattr *nest;
+	int ret;
+
+	nest = rta_nest(rta, len, attr);
+
+	ret = rta_addattr64(rta, len, SEG6_MOBILE_CNT_PACKETS, 0);
+	if (ret < 0)
+		return ret;
+
+	ret = rta_addattr64(rta, len, SEG6_MOBILE_CNT_BYTES, 0);
+	if (ret < 0)
+		return ret;
+
+	ret = rta_addattr64(rta, len, SEG6_MOBILE_CNT_ERRORS, 0);
+	if (ret < 0)
+		return ret;
+
+	rta_nest_end(rta, nest);
+	return 0;
+}
+
+static int parse_encap_seg6mobile(struct rtattr *rta, size_t len, int *argcp,
+				  char ***argvp)
+{
+	int action_ok = 0, nh6_ok = 0, counters_ok = 0;
+	char **argv = *argvp;
+	int argc = *argcp;
+	inet_prefix addr;
+	__u32 action = 0;
+	int ret = 0;
+
+	while (argc > 0) {
+		if (strcmp(*argv, "action") == 0) {
+			NEXT_ARG();
+			if (action_ok++)
+				duparg2("action", *argv);
+			action = read_seg6_mobile_action(*argv);
+			if (!action)
+				invarg("\"action\" value is invalid\n", *argv);
+			ret = rta_addattr32(rta, len, SEG6_MOBILE_ACTION,
+					    action);
+		} else if (strcmp(*argv, "nh6") == 0) {
+			NEXT_ARG();
+			if (nh6_ok++)
+				duparg2("nh6", *argv);
+			get_addr(&addr, *argv, AF_INET6);
+			ret = rta_addattr_l(rta, len, SEG6_MOBILE_NH6,
+					    &addr.data, addr.bytelen);
+		} else if (strcmp(*argv, "count") == 0) {
+			if (counters_ok++)
+				duparg2("count", *argv);
+			ret = seg6mobile_fill_counters(rta, len,
+						       SEG6_MOBILE_COUNTERS);
+		} else {
+			break;
+		}
+		if (ret)
+			return ret;
+		argc--; argv++;
+	}
+
+	if (!action) {
+		fprintf(stderr, "Missing action type\n");
+		exit(-1);
+	}
+
+	*argcp = argc + 1;
+	*argvp = argv - 1;
+
+	return ret;
+}
+
 static int parse_encap_mpls(struct rtattr *rta, size_t len,
 			    int *argcp, char ***argvp)
 {
@@ -2326,6 +2496,9 @@ int lwt_parse_encap(struct rtattr *rta, size_t len, int *argcp, char ***argvp,
 	case LWTUNNEL_ENCAP_XFRM:
 		ret = parse_encap_xfrm(rta, len, &argc, &argv);
 		break;
+	case LWTUNNEL_ENCAP_SEG6_MOBILE:
+		ret = parse_encap_seg6mobile(rta, len, &argc, &argv);
+		break;
 	default:
 		fprintf(stderr, "Error: unsupported encap type\n");
 		break;
diff --git a/man/man8/ip-route.8.in b/man/man8/ip-route.8.in
index 9f29fd436f59..396a1dae9118 100644
--- a/man/man8/ip-route.8.in
+++ b/man/man8/ip-route.8.in
@@ -762,6 +762,9 @@ is a string specifying the supported encapsulation type. Namely:
 .BI seg6local
 - local SRv6 segment processing
 .sp
+.BI seg6mobile
+- SRv6 Mobile User Plane processing (RFC 9433)
+.sp
 .BI ioam6
 - encapsulation type IPv6 IOAM
 .sp
@@ -1083,6 +1086,27 @@ flavors. The Locator-Node Function length must be greater than 0 and evenly
 divisible by 8. This attribute can be used only with NEXT-C-SID flavor.
 .in -4
 
+.B seg6mobile
+.in +2
+.IR SEG6_MOBILE_ACTION " [ "
+.IR SEG6_MOBILE_PARAM " ]"
+- SRv6 Mobile User Plane operation (RFC 9433) to perform on matching
+packets. Currently only the End.MAP behavior is supported.
+.in +2
+
+.B End.MAP nh6
+.I ADDRESS
+- Replace the IPv6 destination address with the configured SID
+.RI ( ADDRESS )
+and forward via the IPv6 FIB without consuming the SRH.
+.in -2
+
+.B count
+- Enable per-CPU packet, byte and error counters for this route.
+The aggregated values are printed by
+.RI \(dq ip "\ -s\ route\ show\(dq."
+.in -2
+
 .B ioam6
 .in +2
 .B freq K/N

-- 
2.50.1