TLA  Line data    Source code

       1                 : /*-------------------------------------------------------------------------
       2                 :  *
       3                 :  * pqcomm.h
       4                 :  *      Definitions common to frontends and backends.
       5                 :  *
       6                 :  * NOTE: for historical reasons, this does not correspond to pqcomm.c.
       7                 :  * pqcomm.c's routines are declared in libpq.h.
       8                 :  *
       9                 :  * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
      10                 :  * Portions Copyright (c) 1994, Regents of the University of California
      11                 :  *
      12                 :  * src/include/libpq/pqcomm.h
      13                 :  *
      14                 :  *-------------------------------------------------------------------------
      15                 :  */
      16                 : #ifndef PQCOMM_H
      17                 : #define PQCOMM_H
      18                 : 
      19                 : #include <sys/socket.h>
      20                 : #include <sys/un.h>
      21                 : #include <netdb.h>
      22                 : #include <netinet/in.h>
      23                 : 
      24                 : typedef struct
      25 ECB             : {
      26                 :     struct sockaddr_storage addr;
      27                 :     socklen_t   salen;
      28                 : } SockAddr;
      29                 : 
      30                 : typedef struct
      31                 : {
      32                 :     int         family;
      33                 :     SockAddr    addr;
      34                 : } AddrInfo;
      35                 : 
      36                 : /* Configure the UNIX socket location for the well known port. */
      37                 : 
      38                 : #define UNIXSOCK_PATH(path, port, sockdir) \
      39                 :        (AssertMacro(sockdir), \
      40                 :         AssertMacro(*(sockdir) != '\0'), \
      41                 :         snprintf(path, sizeof(path), "%s/.s.PGSQL.%d", \
      42                 :                  (sockdir), (port)))
      43                 : 
      44                 : /*
      45                 :  * The maximum workable length of a socket path is what will fit into
      46                 :  * struct sockaddr_un.  This is usually only 100 or so bytes :-(.
      47                 :  *
      48                 :  * For consistency, always pass a MAXPGPATH-sized buffer to UNIXSOCK_PATH(),
      49                 :  * then complain if the resulting string is >= UNIXSOCK_PATH_BUFLEN bytes.
      50                 :  * (Because the standard API for getaddrinfo doesn't allow it to complain in
      51                 :  * a useful way when the socket pathname is too long, we have to test for
      52                 :  * this explicitly, instead of just letting the subroutine return an error.)
      53                 :  */
      54                 : #define UNIXSOCK_PATH_BUFLEN sizeof(((struct sockaddr_un *) NULL)->sun_path)
      55                 : 
      56                 : /*
      57                 :  * A host that looks either like an absolute path or starts with @ is
      58                 :  * interpreted as a Unix-domain socket address.
      59                 :  */
      60                 : static inline bool
      61 GIC       18475 : is_unixsock_path(const char *path)
      62                 : {
      63           18475 :     return is_absolute_path(path) || path[0] == '@';
      64                 : }
      65                 : 
      66                 : /*
      67                 :  * These manipulate the frontend/backend protocol version number.
      68                 :  *
      69                 :  * The major number should be incremented for incompatible changes.  The minor
      70                 :  * number should be incremented for compatible changes (eg. additional
      71                 :  * functionality).
      72                 :  *
      73                 :  * If a backend supports version m.n of the protocol it must actually support
      74                 :  * versions m.[0..n].  Backend support for version m-1 can be dropped after a
      75                 :  * `reasonable' length of time.
      76                 :  *
      77                 :  * A frontend isn't required to support anything other than the current
      78                 :  * version.
      79                 :  */
      80                 : 
      81                 : #define PG_PROTOCOL_MAJOR(v)    ((v) >> 16)
      82                 : #define PG_PROTOCOL_MINOR(v)    ((v) & 0x0000ffff)
      83                 : #define PG_PROTOCOL(m,n)    (((m) << 16) | (n))
      84                 : 
      85                 : /*
      86                 :  * The earliest and latest frontend/backend protocol version supported.
      87                 :  * (Only protocol version 3 is currently supported)
      88                 :  */
      89                 : 
      90                 : #define PG_PROTOCOL_EARLIEST    PG_PROTOCOL(3,0)
      91                 : #define PG_PROTOCOL_LATEST      PG_PROTOCOL(3,0)
      92                 : 
      93                 : typedef uint32 ProtocolVersion; /* FE/BE protocol version number */
      94                 : 
      95                 : typedef ProtocolVersion MsgType;
      96                 : 
      97                 : 
      98                 : /*
      99                 :  * Packet lengths are 4 bytes in network byte order.
     100                 :  *
     101                 :  * The initial length is omitted from the packet layouts appearing below.
     102                 :  */
     103                 : 
     104                 : typedef uint32 PacketLen;
     105                 : 
     106                 : extern PGDLLIMPORT bool Db_user_namespace;
     107                 : 
     108                 : /*
     109                 :  * In protocol 3.0 and later, the startup packet length is not fixed, but
     110                 :  * we set an arbitrary limit on it anyway.  This is just to prevent simple
     111                 :  * denial-of-service attacks via sending enough data to run the server
     112                 :  * out of memory.
     113                 :  */
     114                 : #define MAX_STARTUP_PACKET_LENGTH 10000
     115                 : 
     116                 : 
     117                 : /* These are the authentication request codes sent by the backend. */
     118                 : 
     119                 : #define AUTH_REQ_OK         0   /* User is authenticated  */
     120                 : #define AUTH_REQ_KRB4       1   /* Kerberos V4. Not supported any more. */
     121                 : #define AUTH_REQ_KRB5       2   /* Kerberos V5. Not supported any more. */
     122                 : #define AUTH_REQ_PASSWORD   3   /* Password */
     123                 : #define AUTH_REQ_CRYPT      4   /* crypt password. Not supported any more. */
     124                 : #define AUTH_REQ_MD5        5   /* md5 password */
     125                 : /* 6 is available.  It was used for SCM creds, not supported any more. */
     126                 : #define AUTH_REQ_GSS        7   /* GSSAPI without wrap() */
     127                 : #define AUTH_REQ_GSS_CONT   8   /* Continue GSS exchanges */
     128                 : #define AUTH_REQ_SSPI       9   /* SSPI negotiate without wrap() */
     129                 : #define AUTH_REQ_SASL      10   /* Begin SASL authentication */
     130                 : #define AUTH_REQ_SASL_CONT 11   /* Continue SASL authentication */
     131                 : #define AUTH_REQ_SASL_FIN  12   /* Final SASL message */
     132                 : #define AUTH_REQ_MAX       AUTH_REQ_SASL_FIN    /* maximum AUTH_REQ_* value */
     133                 : 
     134                 : typedef uint32 AuthRequest;
     135                 : 
     136                 : 
     137                 : /*
     138                 :  * A client can also send a cancel-current-operation request to the postmaster.
     139                 :  * This is uglier than sending it directly to the client's backend, but it
     140                 :  * avoids depending on out-of-band communication facilities.
     141                 :  *
     142                 :  * The cancel request code must not match any protocol version number
     143                 :  * we're ever likely to use.  This random choice should do.
     144                 :  */
     145                 : #define CANCEL_REQUEST_CODE PG_PROTOCOL(1234,5678)
     146                 : 
     147                 : typedef struct CancelRequestPacket
     148                 : {
     149                 :     /* Note that each field is stored in network byte order! */
     150                 :     MsgType     cancelRequestCode;  /* code to identify a cancel request */
     151                 :     uint32      backendPID;     /* PID of client's backend */
     152                 :     uint32      cancelAuthCode; /* secret key to authorize cancel */
     153                 : } CancelRequestPacket;
     154                 : 
     155                 : 
     156                 : /*
     157                 :  * A client can also start by sending a SSL or GSSAPI negotiation request to
     158                 :  * get a secure channel.
     159                 :  */
     160                 : #define NEGOTIATE_SSL_CODE PG_PROTOCOL(1234,5679)
     161                 : #define NEGOTIATE_GSS_CODE PG_PROTOCOL(1234,5680)
     162                 : 
     163                 : #endif                          /* PQCOMM_H */