text: /* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
  /***************************************************************************
   * Linux PPP over L2TP (PPPoL2TP) Socket Implementation (RFC 2661)
   *
   * This file supplies definitions required by the PPP over L2TP driver
   * (l2tp_ppp.c).  All version information wrt this file is located in l2tp_ppp.c
   *
   * License:
   *		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 __LINUX_IF_PPPOL2TP_H
  #define __LINUX_IF_PPPOL2TP_H
  
  #include <linux/types.h>
  #include <linux/in.h>
  #include <linux/in6.h>
  #include <linux/l2tp.h>
  
  /* Structure used to connect() the socket to a particular tunnel UDP
   * socket over IPv4.
   */
  struct pppol2tp_addr {
  	__kernel_pid_t	pid;		/* pid that owns the fd.
  					 * 0 => current */
  	int	fd;			/* FD of UDP socket to use */
  
  	struct sockaddr_in addr;	/* IP address and port to send to */
  
  	__u16 s_tunnel, s_session;	/* For matching incoming packets */
  	__u16 d_tunnel, d_session;	/* For sending outgoing packets */
  };
  
  /* Structure used to connect() the socket to a particular tunnel UDP
   * socket over IPv6.
   */
  struct pppol2tpin6_addr {
  	__kernel_pid_t	pid;		/* pid that owns the fd.
  					 * 0 => current */
  	int	fd;			/* FD of UDP socket to use */
  
  	__u16 s_tunnel, s_session;	/* For matching incoming packets */
  	__u16 d_tunnel, d_session;	/* For sending outgoing packets */
  
  	struct sockaddr_in6 addr;	/* IP address and port to send to */
  };
  
  /* The L2TPv3 protocol changes tunnel and session ids from 16 to 32
   * bits. So we need a different sockaddr structure.
   */
  struct pppol2tpv3_addr {
  	__kernel_pid_t	pid;		/* pid that owns the fd.
  					 * 0 => current */
  	int	fd;			/* FD of UDP or IP socket to use */
  
  	struct sockaddr_in addr;	/* IP address and port to send to */
  
  	__u32 s_tunnel, s_session;	/* For matching incoming packets */
  	__u32 d_tunnel, d_session;	/* For sending outgoing packets */
  };
  
  struct pppol2tpv3in6_addr {
  	__kernel_pid_t	pid;		/* pid that owns the fd.
  					 * 0 => current */
  	int	fd;			/* FD of UDP or IP socket to use */
  
  	__u32 s_tunnel, s_session;	/* For matching incoming packets */
  	__u32 d_tunnel, d_session;	/* For sending outgoing packets */
  
  	struct sockaddr_in6 addr;	/* IP address and port to send to */
  };
  
  /* Socket options:
   * DEBUG	- bitmask of debug message categories (not used)
   * SENDSEQ	- 0 => don't send packets with sequence numbers
   *		  1 => send packets with sequence numbers
   * RECVSEQ	- 0 => receive packet sequence numbers are optional
   *		  1 => drop receive packets without sequence numbers
   * LNSMODE	- 0 => act as LAC.
   *		  1 => act as LNS.
   * REORDERTO	- reorder timeout (in millisecs). If 0, don't try to reorder.
   */
  enum {
  	PPPOL2TP_SO_DEBUG	= 1,
  	PPPOL2TP_SO_RECVSEQ	= 2,
  	PPPOL2TP_SO_SENDSEQ	= 3,
  	PPPOL2TP_SO_LNSMODE	= 4,
  	PPPOL2TP_SO_REORDERTO	= 5,
  };
  
  /* Debug message categories for the DEBUG socket option (deprecated) */
  enum {
  	PPPOL2TP_MSG_DEBUG	= L2TP_MSG_DEBUG,
  	PPPOL2TP_MSG_CONTROL	= L2TP_MSG_CONTROL,
  	PPPOL2TP_MSG_SEQ	= L2TP_MSG_SEQ,
  	PPPOL2TP_MSG_DATA	= L2TP_MSG_DATA,
  };
  
  
  
  #endif /* __LINUX_IF_PPPOL2TP_H */
  