linux/include/net/gtp.h
Wojciech Drewek 9af41cc334 gtp: Implement GTP echo response
Adding GTP device through ip link creates the situation where
there is no userspace daemon which would handle GTP messages
(Echo Request for example). GTP-U instance which would not respond
to echo requests would violate GTP specification.

When GTP packet arrives with GTP_ECHO_REQ message type,
GTP_ECHO_RSP is send to the sender. GTP_ECHO_RSP message
should contain information element with GTPIE_RECOVERY tag and
restart counter value. For GTPv1 restart counter is not used
and should be equal to 0, for GTPv0 restart counter contains
information provided from userspace(IFLA_GTP_RESTART_COUNT).

Signed-off-by: Wojciech Drewek <wojciech.drewek@intel.com>
Suggested-by: Harald Welte <laforge@gnumonks.org>
Reviewed-by: Harald Welte <laforge@gnumonks.org>
Tested-by: Harald Welte <laforge@gnumonks.org>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
2022-03-11 08:27:16 -08:00

67 lines
1.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _GTP_H_
#define _GTP_H_
/* General GTP protocol related definitions. */
#define GTP0_PORT 3386
#define GTP1U_PORT 2152
/* GTP messages types */
#define GTP_ECHO_REQ 1 /* Echo Request */
#define GTP_ECHO_RSP 2 /* Echo Response */
#define GTP_TPDU 255
#define GTPIE_RECOVERY 14
struct gtp0_header { /* According to GSM TS 09.60. */
__u8 flags;
__u8 type;
__be16 length;
__be16 seq;
__be16 flow;
__u8 number;
__u8 spare[3];
__be64 tid;
} __attribute__ ((packed));
struct gtp1_header { /* According to 3GPP TS 29.060. */
__u8 flags;
__u8 type;
__be16 length;
__be32 tid;
} __attribute__ ((packed));
struct gtp1_header_long { /* According to 3GPP TS 29.060. */
__u8 flags;
__u8 type;
__be16 length;
__be32 tid;
__be16 seq;
__u8 npdu;
__u8 next;
} __packed;
/* GTP Information Element */
struct gtp_ie {
__u8 tag;
__u8 val;
} __packed;
struct gtp0_packet {
struct gtp0_header gtp0_h;
struct gtp_ie ie;
} __packed;
struct gtp1u_packet {
struct gtp1_header_long gtp1u_h;
struct gtp_ie ie;
} __packed;
#define GTP1_F_NPDU 0x01
#define GTP1_F_SEQ 0x02
#define GTP1_F_EXTHDR 0x04
#define GTP1_F_MASK 0x07
#endif