postgresql/src/include/libpq/pqcomm.h

/*-------------------------------------------------------------------------
 *
 * pqcomm.h--
 *	  Parameters for the communication module
 *
 *
 * Copyright (c) 1994, Regents of the University of California
 *
 * $Id: pqcomm.h,v 1.18 1998/01/24 22:49:23 momjian Exp $
 *
 * NOTES
 *	  Some of this should move to libpq.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef PQCOMM_H
#define PQCOMM_H

#include <stdio.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/un.h>


/*
 * startup msg parameters: path length, argument string length
 */
#define PATH_SIZE		64
#define ARGV_SIZE		64

#define UNIXSOCK_PATH(sun,port) \
  sprintf(sun.sun_path,"/tmp/.s.PGSQL.%d",port) + sizeof(sun.sun_family) + 1;


/* The various kinds of startup messages are for the various kinds of
   user authentication systems.  In the beginning, there was only
   STARTUP_MSG and all connections were unauthenticated.  Now, there are
   several choices of authentication method (the client picks one, but
   the server needn't necessarily accept it).  So now, the STARTUP_MSG
   message means to start either an unauthenticated or a host-based
   authenticated connection, depending on what the server prefers.	This
   is possible because the protocol between server and client is the same
   in both cases (basically, no negotiation is required at all).
   */

typedef enum _MsgType
{
	ACK_MSG = 0,				/* acknowledge a message */
	ERROR_MSG = 1,				/* error response to client from server */
	RESET_MSG = 2,				/* client must reset connection */
	PRINT_MSG = 3,				/* tuples for client from server */
	NET_ERROR = 4,				/* error in net system call */
	FUNCTION_MSG = 5,			/* fastpath call (unused) */
	QUERY_MSG = 6,				/* client query to server */
	STARTUP_MSG = 7,			/* initialize a connection with a backend */
	DUPLICATE_MSG = 8,			/* duplicate msg arrived (errors msg only) */
	INVALID_MSG = 9,			/* for some control functions */
	STARTUP_KRB4_MSG = 10,		/* krb4 session follows startup packet */
	STARTUP_KRB5_MSG = 11,		/* krb5 session follows startup packet */
	STARTUP_HBA_MSG = 12,		/* use host-based authentication */
	STARTUP_UNAUTH_MSG = 13,	/* use unauthenticated connection */
	STARTUP_PASSWORD_MSG = 14,	/* use plaintext password authentication */
        /* The following three are not really a named authentication method
           * since the front end has no choice in choosing the method.  The
           * backend sends the SALT/UNSALT messages back to the frontend after
           * the USER login has been given to the backend.
           */
	STARTUP_CRYPT_MSG = 15,               /* use crypt()'ed password authentication */
	STARTUP_USER_MSG = 16,          /* send user name to check pg_user for password */
	STARTUP_SALT_MSG = 17,          /* frontend should crypt the password it sends */
	STARTUP_UNSALT_MSG = 18         /* frontend should NOT crypt the password it sends */
	/* insert new values here -- DO NOT REORDER OR DELETE ENTRIES */
	/* also change LAST_AUTHENTICATION_TYPE below and add to the */
	/* authentication_type_name[] array in pqcomm.c */
} MsgType;

#define LAST_AUTHENTICATION_TYPE 14

typedef char *Addr;
typedef int PacketLen;			/* packet length */


typedef struct StartupInfo
{
/*	   PacketHdr		hdr; */
	char		database[PATH_SIZE];	/* database name */
	char		user[NAMEDATALEN];		/* user name */
	char		options[ARGV_SIZE];		/* possible additional args */
	char		execFile[ARGV_SIZE];	/* possible backend to use */
	char		tty[PATH_SIZE]; /* possible tty for debug output */
} StartupInfo;

/* amount of available data in a packet buffer */
#define MESSAGE_SIZE	sizeof(StartupInfo)

/* I/O can be blocking or non-blocking */
#define BLOCKING		(FALSE)
#define NON_BLOCKING	(TRUE)

/* a PacketBuf gets shipped from client to server so be careful
   of differences in representation.
   Be sure to use htonl() and ntohl() on the len and msgtype fields! */
typedef struct PacketBuf
{
	int			len;
	MsgType		msgtype;
	char		data[MESSAGE_SIZE];
} PacketBuf;

/* update the conversion routines
  StartupInfo2PacketBuf() and PacketBuf2StartupInfo() (decl. below)
  if StartupInfo or PacketBuf structs ever change */

/*
 * socket descriptor port
 *		we need addresses of both sides to do authentication calls
 */
typedef struct Port
{
	int			sock;			/* file descriptor */
	int			mask;			/* select mask */
	int			nBytes;			/* nBytes read in so far */
	/* local addr (us) */
        union {  struct sockaddr_in in; struct sockaddr_un un; } laddr;
        /* remote addr (them) */
        union {  struct sockaddr_in in; struct sockaddr_un un; }  raddr;
	/*
	 * PacketBufId				id;
*//* id of packet buf currently in use */
	PacketBuf	buf;			/* stream implementation (curr pack buf) */
	char		salt[2];
} Port;

/* invalid socket descriptor */
#define INVALID_SOCK	(-1)

#define INVALID_ID (-1)
#define MAX_CONNECTIONS 10
#define N_PACK_BUFS		20

/* no multi-packet messages yet */
#define MAX_PACKET_BACKLOG		1

#define DEFAULT_STRING			""

extern FILE *Pfout,
		   *Pfin;
extern int	PQAsyncNotifyWaiting;

/* in pqcompriv.c */
int			pqGetShort(int *, FILE *);
int			pqGetLong(int *, FILE *);
int			pqGetNBytes(char *, size_t, FILE *);
int			pqGetString(char *, size_t, FILE *);
int			pqGetByte(FILE *);

int			pqPutShort(int, FILE *);
int			pqPutLong(int, FILE *);
int			pqPutNBytes(const char *, size_t, FILE *);
int			pqPutString(const char *, FILE *);
int			pqPutByte(int, FILE *);

/*
 * prototypes for functions in pqpacket.c
 */
extern int	PacketReceive(Port *port, PacketBuf *buf, char nonBlocking);
extern int PacketSend(Port *port, PacketBuf *buf,
		   PacketLen len, char nonBlocking);

/* extern PacketBuf* StartupInfo2PacketBuf(StartupInfo*); */
/* extern StartupInfo* PacketBuf2StartupInfo(PacketBuf*); */
extern char *name_of_authentication_type(int type);

#endif							/* PQCOMM_H */