text: /*-------------------------------------------------------------------------
   *
   * pqcomm.h
   *		Definitions common to frontends and backends.
   *
   * NOTE: for historical reasons, this does not correspond to pqcomm.c.
   * pqcomm.c's routines are declared in libpq.h.
   *
   * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
   * Portions Copyright (c) 1994, Regents of the University of California
   *
   * $PostgreSQL: pgsql/src/include/libpq/pqcomm.h,v 1.110 2009/01/01 17:23:59 momjian Exp $
   *
   *-------------------------------------------------------------------------
   */
  #ifndef PQCOMM_H
  #define PQCOMM_H
  
  #include <sys/socket.h>
  #include <netdb.h>
  #ifdef HAVE_SYS_UN_H
  #include <sys/un.h>
  #endif
  #include <netinet/in.h>
  
  #ifdef HAVE_STRUCT_SOCKADDR_STORAGE
  
  #ifndef HAVE_STRUCT_SOCKADDR_STORAGE_SS_FAMILY
  #ifdef HAVE_STRUCT_SOCKADDR_STORAGE___SS_FAMILY
  #define ss_family __ss_family
  #else
  #error struct sockaddr_storage does not provide an ss_family member
  #endif
  #endif
  
  #ifdef HAVE_STRUCT_SOCKADDR_STORAGE___SS_LEN
  #define ss_len __ss_len
  #define HAVE_STRUCT_SOCKADDR_STORAGE_SS_LEN 1
  #endif
  #else							/* !HAVE_STRUCT_SOCKADDR_STORAGE */
  
  /* Define a struct sockaddr_storage if we don't have one. */
  
  struct sockaddr_storage
  {
  	union
  	{
  		struct sockaddr sa;		/* get the system-dependent fields */
  		int64		ss_align;	/* ensures struct is properly aligned */
  		char		ss_pad[128];	/* ensures struct has desired size */
  	}			ss_stuff;
  };
  
  #define ss_family	ss_stuff.sa.sa_family
  /* It should have an ss_len field if sockaddr has sa_len. */
  #ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
  #define ss_len		ss_stuff.sa.sa_len
  #define HAVE_STRUCT_SOCKADDR_STORAGE_SS_LEN 1
  #endif
  #endif   /* HAVE_STRUCT_SOCKADDR_STORAGE */
  
  typedef struct
  {
  	struct sockaddr_storage addr;
  	socklen_t salen;
  } SockAddr;
  
  /* Configure the UNIX socket location for the well known port. */
  
  #define UNIXSOCK_PATH(path, port, sockdir) \
  		snprintf(path, sizeof(path), "%s/.s.PGSQL.%d", \
  				((sockdir) && *(sockdir) != '\0') ? (sockdir) : \
  				DEFAULT_PGSOCKET_DIR, \
  				(port))
  
  /*
   * The maximum workable length of a socket path is what will fit into
   * struct sockaddr_un.  This is usually only 100 or so bytes :-(.
   *
   * For consistency, always pass a MAXPGPATH-sized buffer to UNIXSOCK_PATH(),
   * then complain if the resulting string is >= UNIXSOCK_PATH_BUFLEN bytes.
   * (Because the standard API for getaddrinfo doesn't allow it to complain in
   * a useful way when the socket pathname is too long, we have to test for
   * this explicitly, instead of just letting the subroutine return an error.)
   */
  #define UNIXSOCK_PATH_BUFLEN sizeof(((struct sockaddr_un *) NULL)->sun_path)
  
  
  /*
   * These manipulate the frontend/backend protocol version number.
   *
   * The major number should be incremented for incompatible changes.  The minor
   * number should be incremented for compatible changes (eg. additional
   * functionality).
   *
   * If a backend supports version m.n of the protocol it must actually support
   * versions m.[0..n].  Backend support for version m-1 can be dropped after a
   * `reasonable' length of time.
   *
   * A frontend isn't required to support anything other than the current
   * version.
   */
  /* Upper four bits used special by GPDB */
  #define PG_PROTOCOL_MAJOR(v)	(((v) >> 16) & 0xfff)
  #define PG_PROTOCOL_MINOR(v)	((v) & 0x0000ffff)
  #define PG_PROTOCOL(m,n)	(((m) << 16) | (n))
  
  /* The earliest and latest frontend/backend protocol version supported. */
  
  #define PG_PROTOCOL_EARLIEST	PG_PROTOCOL(1,0)
  #define PG_PROTOCOL_LATEST		PG_PROTOCOL(3,0)
  
  typedef uint32 ProtocolVersion; /* FE/BE protocol version number */
  
  typedef ProtocolVersion MsgType;
  
  
  /*
   * Packet lengths are 4 bytes in network byte order.
   *
   * The initial length is omitted from the packet layouts appearing below.
   */
  
  typedef uint32 PacketLen;
  
  
  /*
   * Old-style startup packet layout with fixed-width fields.  This is used in
   * protocol 1.0 and 2.0, but not in later versions.  Note that the fields
   * in this layout are '\0' terminated only if there is room.
   */
  
  #define SM_DATABASE		64
  #define SM_USER			32
  /* We append database name if db_user_namespace true. */
  #define SM_DATABASE_USER (SM_DATABASE+SM_USER+1)		/* +1 for @ */
  #define SM_OPTIONS		64
  #define SM_UNUSED		64
  #define SM_TTY			64
  
  typedef struct StartupPacket
  {
  	ProtocolVersion protoVersion;		/* Protocol version */
  	char		database[SM_DATABASE];	/* Database name */
  	/* Db_user_namespace appends dbname */
  	char		user[SM_USER];	/* User name */
  	char		options[SM_OPTIONS];	/* Optional additional args */
  	char		unused[SM_UNUSED];		/* Unused */
  	char		tty[SM_TTY];	/* Tty for debug output */
  } StartupPacket;
  
  extern bool Db_user_namespace;
  
  /*
   * In protocol 3.0 and later, the startup packet length is not fixed, but
   * we set an arbitrary limit on it anyway.	This is just to prevent simple
   * denial-of-service attacks via sending enough data to run the server
   * out of memory.
   */
  #define MAX_STARTUP_PACKET_LENGTH 64000
  
  
  /* These are the authentication request codes sent by the backend. */
  
  #define AUTH_REQ_OK			0	/* User is authenticated  */
  #define AUTH_REQ_KRB4		1	/* Kerberos V4. Not supported any more. */
  #define AUTH_REQ_KRB5		2	/* Kerberos V5 */
  #define AUTH_REQ_PASSWORD	3	/* Password */
  #define AUTH_REQ_CRYPT		4	/* crypt password. Not supported any more. */
  #define AUTH_REQ_MD5		5	/* md5 password */
  #define AUTH_REQ_SCM_CREDS	6	/* transfer SCM credentials */
  #define AUTH_REQ_GSS		7	/* GSSAPI without wrap() */
  #define AUTH_REQ_GSS_CONT	8	/* Continue GSS exchanges */
  #define AUTH_REQ_SSPI		9	/* SSPI negotiate without wrap() */
  
  typedef uint32 AuthRequest;
  
  
  /*
   * A client can also send a cancel-current-operation request to the postmaster.
   * This is uglier than sending it directly to the client's backend, but it
   * avoids depending on out-of-band communication facilities.
   *
   * The cancel request code must not match any protocol version number
   * we're ever likely to use.  This random choice should do.
   */
  #define CANCEL_REQUEST_CODE PG_PROTOCOL(1234,5678)
  
  /*
   * query-finish operation is a special message betweeen QD and QE, used to
   * indicate that QD is successfully finishing the current query so that
   * QE can finish its work at the earliest point.  Though executor has
   * a way to squelch QEs, it is necessary to have asynchronous message
   * by signal.
   */
  #define FINISH_REQUEST_CODE PG_PROTOCOL(1234,5677)
  
  typedef struct CancelRequestPacket
  {
  	/* Note that each field is stored in network byte order! */
  	MsgType		cancelRequestCode;		/* code to identify a cancel request */
  	uint32		backendPID;		/* PID of client's backend */
  	uint32		cancelAuthCode; /* secret key to authorize cancel */
  } CancelRequestPacket;
  
  
  /*
   * A client can also start by sending a SSL negotiation request, to get a
   * secure channel.
   */
  #define NEGOTIATE_SSL_CODE PG_PROTOCOL(1234,5679)
  
  /*
   * Filerep Add a pre-startup message primary-mirror-transition-request,
   * and a primary-mirror-transition-query
   */
  #define PRIMARY_MIRROR_TRANSITION_REQUEST_CODE PG_PROTOCOL(1234,5680)
  #define PRIMARY_MIRROR_TRANSITION_QUERY_CODE PG_PROTOCOL(1234,5681)
  
  typedef struct PrimaryMirrorTransitionPacket
  {
  	MsgType protocolCode;
  	PacketLen dataLength;
  } PrimaryMirrorTransitionPacket;
  
  /* the number of times trying to acquire the send mutex for the front
   * end connection after detecting process is exitting */
  #define PQ_BUSY_TEST_COUNT_IN_EXITING 5
  
  #define GPCONN_TYPE "gpconntype"
  #define GPCONN_TYPE_FTS "fts"
  
  #endif   /* PQCOMM_H */
  