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/*-------------------------------------------------------------------------
*
* 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) 1996-2020, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/libpq/pqcomm.h
*
*-------------------------------------------------------------------------
*/
#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;
ACCEPT_TYPE_ARG3 salen;
} SockAddr;
/* Configure the UNIX socket location for the well known port. */
#define UNIXSOCK_PATH(path, port, sockdir) \
(AssertMacro(sockdir), \
AssertMacro(*(sockdir) != '\0'), \
snprintf(path, sizeof(path), "%s/.s.PGSQL.%d", \
(sockdir), (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.
*/
#define PG_PROTOCOL_MAJOR(v) ((v) >> 16)
#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(2,0)
#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 10000
/* 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. Not supported any more. */
#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() */
#define AUTH_REQ_SASL 10 /* Begin SASL authentication */
#define AUTH_REQ_SASL_CONT 11 /* Continue SASL authentication */
#define AUTH_REQ_SASL_FIN 12 /* Final SASL message */
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)
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 or GSSAPI negotiation request to
* get a secure channel.
*/
#define NEGOTIATE_SSL_CODE PG_PROTOCOL(1234,5679)
#define NEGOTIATE_GSS_CODE PG_PROTOCOL(1234,5680)
#endif /* PQCOMM_H */