src/include/libpq/pqcomm.h

   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) 1996-2008, PostgreSQL Global Development Group
  10  * Portions Copyright (c) 1994, Regents of the University of California
  11  *
  12  * $PostgreSQL$
  13  *
  14  *-------------------------------------------------------------------------
  15  */
  16 #ifndef PQCOMM_H
  17 #define PQCOMM_H
  18
  19 #include <sys/socket.h>
  20 #include <netdb.h>
  21 #ifdef HAVE_SYS_UN_H
  22 #include <sys/un.h>
  23 #endif
  24 #include <netinet/in.h>
  25
  26 #ifdef HAVE_STRUCT_SOCKADDR_STORAGE
  27
  28 #ifndef HAVE_STRUCT_SOCKADDR_STORAGE_SS_FAMILY
  29 #ifdef HAVE_STRUCT_SOCKADDR_STORAGE___SS_FAMILY
  30 #define ss_family __ss_family
  31 #else
  32 #error struct sockaddr_storage does not provide an ss_family member
  33 #endif
  34 #endif
  35
  36 #ifdef HAVE_STRUCT_SOCKADDR_STORAGE___SS_LEN
  37 #define ss_len __ss_len
  38 #define HAVE_STRUCT_SOCKADDR_STORAGE_SS_LEN 1
  39 #endif
  40 #else                                                   /* !HAVE_STRUCT_SOCKADDR_STORAGE */
  41
  42 /* Define a struct sockaddr_storage if we don't have one. */
  43
  44 struct sockaddr_storage
  45 {
  46         union
  47         {
  48                 struct sockaddr sa;             /* get the system-dependent fields */
  49                 int64           ss_align;       /* ensures struct is properly aligned */
  50                 char            ss_pad[128];    /* ensures struct has desired size */
  51         }                       ss_stuff;
  52 };
  53
  54 #define ss_family       ss_stuff.sa.sa_family
  55 /* It should have an ss_len field if sockaddr has sa_len. */
  56 #ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
  57 #define ss_len          ss_stuff.sa.sa_len
  58 #define HAVE_STRUCT_SOCKADDR_STORAGE_SS_LEN 1
  59 #endif
  60 #endif   /* HAVE_STRUCT_SOCKADDR_STORAGE */
  61
  62 typedef struct
  63 {
  64         struct sockaddr_storage addr;
  65         ACCEPT_TYPE_ARG3 salen;
  66 } SockAddr;
  67
  68 /* Configure the UNIX socket location for the well known port. */
  69
  70 #define UNIXSOCK_PATH(path, port, sockdir) \
  71                 snprintf(path, sizeof(path), "%s/.s.PGSQL.%d", \
  72                                 ((sockdir) && *(sockdir) != '\0') ? (sockdir) : \
  73                                 DEFAULT_PGSOCKET_DIR, \
  74                                 (port))
  75
  76 /*
  77  * These manipulate the frontend/backend protocol version number.
  78  *
  79  * The major number should be incremented for incompatible changes.  The minor
  80  * number should be incremented for compatible changes (eg. additional
  81  * functionality).
  82  *
  83  * If a backend supports version m.n of the protocol it must actually support
  84  * versions m.[0..n].  Backend support for version m-1 can be dropped after a
  85  * `reasonable' length of time.
  86  *
  87  * A frontend isn't required to support anything other than the current
  88  * version.
  89  */
  90
  91 #define PG_PROTOCOL_MAJOR(v)    ((v) >> 16)
  92 #define PG_PROTOCOL_MINOR(v)    ((v) & 0x0000ffff)
  93 #define PG_PROTOCOL(m,n)        (((m) << 16) | (n))
  94
  95 /* The earliest and latest frontend/backend protocol version supported. */
  96
  97 #define PG_PROTOCOL_EARLIEST    PG_PROTOCOL(1,0)
  98 #define PG_PROTOCOL_LATEST              PG_PROTOCOL(3,0)
  99
 100 typedef uint32 ProtocolVersion; /* FE/BE protocol version number */
 101
 102 typedef ProtocolVersion MsgType;
 103
 104
 105 /*
 106  * Packet lengths are 4 bytes in network byte order.
 107  *
 108  * The initial length is omitted from the packet layouts appearing below.
 109  */
 110
 111 typedef uint32 PacketLen;
 112
 113
 114 /*
 115  * Old-style startup packet layout with fixed-width fields.  This is used in
 116  * protocol 1.0 and 2.0, but not in later versions.  Note that the fields
 117  * in this layout are '\0' terminated only if there is room.
 118  */
 119
 120 #define SM_DATABASE             64
 121 #define SM_USER                 32
 122 /* We append database name if db_user_namespace true. */
 123 #define SM_DATABASE_USER (SM_DATABASE+SM_USER+1)                /* +1 for @ */
 124 #define SM_OPTIONS              64
 125 #define SM_UNUSED               64
 126 #define SM_TTY                  64
 127
 128 typedef struct StartupPacket
 129 {
 130         ProtocolVersion protoVersion;           /* Protocol version */
 131         char            database[SM_DATABASE];  /* Database name */
 132         /* Db_user_namespace appends dbname */
 133         char            user[SM_USER];  /* User name */
 134         char            options[SM_OPTIONS];    /* Optional additional args */
 135         char            unused[SM_UNUSED];              /* Unused */
 136         char            tty[SM_TTY];    /* Tty for debug output */
 137 } StartupPacket;
 138
 139 extern bool Db_user_namespace;
 140
 141 /*
 142  * In protocol 3.0 and later, the startup packet length is not fixed, but
 143  * we set an arbitrary limit on it anyway.      This is just to prevent simple
 144  * denial-of-service attacks via sending enough data to run the server
 145  * out of memory.
 146  */
 147 #define MAX_STARTUP_PACKET_LENGTH 10000
 148
 149
 150 /* These are the authentication request codes sent by the backend. */
 151
 152 #define AUTH_REQ_OK                     0       /* User is authenticated  */
 153 #define AUTH_REQ_KRB4           1       /* Kerberos V4. Not supported any more. */
 154 #define AUTH_REQ_KRB5           2       /* Kerberos V5 */
 155 #define AUTH_REQ_PASSWORD       3       /* Password */
 156 #define AUTH_REQ_CRYPT          4       /* crypt password. Not supported any more. */
 157 #define AUTH_REQ_MD5            5       /* md5 password */
 158 #define AUTH_REQ_SCM_CREDS      6       /* transfer SCM credentials */
 159 #define AUTH_REQ_GSS            7       /* GSSAPI without wrap() */
 160 #define AUTH_REQ_GSS_CONT       8       /* Continue GSS exchanges */
 161 #define AUTH_REQ_SSPI           9       /* SSPI negotiate without wrap() */
 162
 163 typedef uint32 AuthRequest;
 164
 165
 166 /*
 167  * A client can also send a cancel-current-operation request to the postmaster.
 168  * This is uglier than sending it directly to the client's backend, but it
 169  * avoids depending on out-of-band communication facilities.
 170  *
 171  * The cancel request code must not match any protocol version number
 172  * we're ever likely to use.  This random choice should do.
 173  */
 174 #define CANCEL_REQUEST_CODE PG_PROTOCOL(1234,5678)
 175
 176 typedef struct CancelRequestPacket
 177 {
 178         /* Note that each field is stored in network byte order! */
 179         MsgType         cancelRequestCode;              /* code to identify a cancel request */
 180         uint32          backendPID;             /* PID of client's backend */
 181         uint32          cancelAuthCode; /* secret key to authorize cancel */
 182 } CancelRequestPacket;
 183
 184
 185 /*
 186  * A client can also start by sending a SSL negotiation request, to get a
 187  * secure channel.
 188  */
 189 #define NEGOTIATE_SSL_CODE PG_PROTOCOL(1234,5679)
 190
 191 #endif   /* PQCOMM_H */