rfc3493.txt

bind 9.3结合mysql数据库

   Note:

   1. If the caller handles only TCP and not UDP, for example, then the
      ai_protocol member of the hints structure should be set to
      IPPROTO_TCP when getaddrinfo() is called.

   2. If the caller handles only IPv4 and not IPv6, then the ai_family
      member of the hints structure should be set to AF_INET when
      getaddrinfo() is called.







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   The ai_flags field to which hints parameter points shall be set to
   zero or be the bitwise-inclusive OR of one or more of the values
   AI_PASSIVE, AI_CANONNAME, AI_NUMERICHOST, AI_NUMERICSERV,
   AI_V4MAPPED, AI_ALL, and AI_ADDRCONFIG.

   If the AI_PASSIVE flag is specified, the returned address information
   shall be suitable for use in binding a socket for accepting incoming
   connections for the specified service (i.e., a call to bind()).  In
   this case, if the nodename argument is null, then the IP address
   portion of the socket address structure shall be set to INADDR_ANY
   for an IPv4 address or IN6ADDR_ANY_INIT for an IPv6 address.  If the
   AI_PASSIVE flag is not specified, the returned address information
   shall be suitable for a call to connect() (for a connection-mode
   protocol) or for a call to connect(), sendto() or sendmsg() (for a
   connectionless protocol).  In this case, if the nodename argument is
   null, then the IP address portion of the socket address structure
   shall be set to the loopback address.  This flag is ignored if the
   nodename argument is not null.

   If the AI_CANONNAME flag is specified and the nodename argument is
   not null, the function shall attempt to determine the canonical name
   corresponding to nodename (for example, if nodename is an alias or
   shorthand notation for a complete name).

   If the AI_NUMERICHOST flag is specified, then a non-null nodename
   string supplied shall be a numeric host address string.  Otherwise,
   an [EAI_NONAME] error is returned.  This flag shall prevent any type
   of name resolution service (for example, the DNS) from being invoked.

   If the AI_NUMERICSERV flag is specified, then a non-null servname
   string supplied shall be a numeric port string.  Otherwise, an
   [EAI_NONAME] error shall be returned.  This flag shall prevent any
   type of name resolution service (for example, NIS+) from being
   invoked.

   If the AI_V4MAPPED flag is specified along with an ai_family of
   AF_INET6, then getaddrinfo() shall return IPv4-mapped IPv6 addresses
   on finding no matching IPv6 addresses (ai_addrlen shall be 16).

      For example, when using the DNS, if no AAAA records are found then
      a query is made for A records and any found are returned as IPv4-
      mapped IPv6 addresses.

   The AI_V4MAPPED flag shall be ignored unless ai_family equals
   AF_INET6.

   If the AI_ALL flag is used with the AI_V4MAPPED flag, then
   getaddrinfo() shall return all matching IPv6 and IPv4 addresses.



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      For example, when using the DNS, queries are made for both AAAA
      records and A records, and getaddrinfo() returns the combined
      results of both queries.  Any IPv4 addresses found are returned as
      IPv4-mapped IPv6 addresses.

   The AI_ALL flag without the AI_V4MAPPED flag is ignored.

      Note:

      When ai_family is not specified (AF_UNSPEC), AI_V4MAPPED and
      AI_ALL flags will only be used if AF_INET6 is supported.

   If the AI_ADDRCONFIG flag is specified, IPv4 addresses shall be
   returned only if an IPv4 address is configured on the local system,
   and IPv6 addresses shall be returned only if an IPv6 address is
   configured on the local system.  The loopback address is not
   considered for this case as valid as a configured address.

      For example, when using the DNS, a query for AAAA records should
      occur only if the node has at least one IPv6 address configured
      (other than IPv6 loopback) and a query for A records should occur
      only if the node has at least one IPv4 address configured (other
      than the IPv4 loopback).

   The ai_socktype field to which argument hints points specifies the
   socket type for the service, as defined for socket().  If a specific
   socket type is not given (for example, a value of zero) and the
   service name could be interpreted as valid with multiple supported
   socket types, the implementation shall attempt to resolve the service
   name for all supported socket types and, in the absence of errors,
   all possible results shall be returned.  A non-zero socket type value
   shall limit the returned information to values with the specified
   socket type.

   If the ai_family field to which hints points has the value AF_UNSPEC,
   addresses shall be returned for use with any address family that can
   be used with the specified nodename and/or servname.  Otherwise,
   addresses shall be returned for use only with the specified address
   family.  If ai_family is not AF_UNSPEC and ai_protocol is not zero,
   then addresses are returned for use only with the specified address
   family and protocol; the value of ai_protocol shall be interpreted as
   in a call to the socket() function with the corresponding values of
   ai_family and ai_protocol.

   The freeaddrinfo() function frees one or more addrinfo structures
   returned by getaddrinfo(), along with any additional storage
   associated with those structures (for example, storage pointed to by
   the ai_canonname and ai_addr fields; an application must not



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   reference this storage after the associated addrinfo structure has
   been freed).  If the ai_next field of the structure is not null, the
   entire list of structures is freed.  The freeaddrinfo() function must
   support the freeing of arbitrary sublists of an addrinfo list
   originally returned by getaddrinfo().

   Functions getaddrinfo() and freeaddrinfo() must be thread-safe.

   A zero return value for getaddrinfo() indicates successful
   completion; a non-zero return value indicates failure.  The possible
   values for the failures are listed below under Error Return Values.

   Upon successful return of getaddrinfo(), the location to which res
   points shall refer to a linked list of addrinfo structures, each of
   which shall specify a socket address and information for use in
   creating a socket with which to use that socket address.  The list
   shall include at least one addrinfo structure.  The ai_next field of
   each structure contains a pointer to the next structure on the list,
   or a null pointer if it is the last structure on the list.  Each
   structure on the list shall include values for use with a call to the
   socket() function, and a socket address for use with the connect()
   function or, if the AI_PASSIVE flag was specified, for use with the
   bind() function.  The fields ai_family, ai_socktype, and ai_protocol
   shall be usable as the arguments to the socket() function to create a
   socket suitable for use with the returned address.  The fields
   ai_addr and ai_addrlen are usable as the arguments to the connect()
   or bind() functions with such a socket, according to the AI_PASSIVE
   flag.

   If nodename is not null, and if requested by the AI_CANONNAME flag,
   the ai_canonname field of the first returned addrinfo structure shall
   point to a null-terminated string containing the canonical name
   corresponding to the input nodename; if the canonical name is not
   available, then ai_canonname shall refer to the nodename argument or
   a string with the same contents.  The contents of the ai_flags field
   of the returned structures are undefined.

   All fields in socket address structures returned by getaddrinfo()
   that are not filled in through an explicit argument (for example,
   sin6_flowinfo) shall be set to zero.

   Note: This makes it easier to compare socket address structures.









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   Error Return Values:

   The getaddrinfo() function shall fail and return the corresponding
   value if:

   [EAI_AGAIN]     The name could not be resolved at this time.  Future
                   attempts may succeed.

   [EAI_BADFLAGS]  The flags parameter had an invalid value.

   [EAI_FAIL]      A non-recoverable error occurred when attempting to
                   resolve the name.

   [EAI_FAMILY]    The address family was not recognized.

   [EAI_MEMORY]    There was a memory allocation failure when trying to
                   allocate storage for the return value.

   [EAI_NONAME]    The name does not resolve for the supplied
                   parameters.  Neither nodename nor servname were
                   supplied.  At least one of these must be supplied.

   [EAI_SERVICE]   The service passed was not recognized for the
                   specified socket type.

   [EAI_SOCKTYPE]  The intended socket type was not recognized.

   [EAI_SYSTEM]    A system error occurred; the error code can be found
                   in errno.

   The gai_strerror() function provides a descriptive text string
   corresponding to an EAI_xxx error value.

      #include <netdb.h>

      const char *gai_strerror(int ecode);

   The argument is one of the EAI_xxx values defined for the
   getaddrinfo() and getnameinfo() functions.  The return value points
   to a string describing the error.  If the argument is not one of the
   EAI_xxx values, the function still returns a pointer to a string
   whose contents indicate an unknown error.

6.2 Socket Address Structure to Node Name and Service Name

   The getnameinfo() function is used to translate the contents of a
   socket address structure to a node name and/or service name.




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   #include <sys/socket.h>
   #include <netdb.h>

   int getnameinfo(const struct sockaddr *sa, socklen_t salen,
                       char *node, socklen_t nodelen,
                       char *service, socklen_t servicelen,
                         int flags);

   The getnameinfo() function shall translate a socket address to a node
   name and service location, all of which are defined as in
   getaddrinfo().

   The sa argument points to a socket address structure to be
   translated.

   The salen argument holds the size of the socket address structure
   pointed to by sa.

   If the socket address structure contains an IPv4-mapped IPv6 address
   or an IPv4-compatible IPv6 address, the implementation shall extract
   the embedded IPv4 address and lookup the node name for that IPv4
   address.

      Note: The IPv6 unspecified address ("::") and the IPv6 loopback
      address ("::1") are not IPv4-compatible addresses.  If the address
      is the IPv6 unspecified address ("::"), a lookup is not performed,
      and the [EAI_NONAME] error is returned.

   If the node argument is non-NULL and the nodelen argument is nonzero,
   then the node argument points to a buffer able to contain up to
   nodelen characters that receives the node name as a null-terminated
   string.  If the node argument is NULL or the nodelen argument is
   zero, the node name shall not be returned.  If the node's name cannot
   be located, the numeric form of the node's address is returned
   instead of its name.

   If the service argument is non-NULL and the servicelen argument is
   non-zero, then the service argument points to a buffer able to
   contain up to servicelen bytes that receives the service name as a
   null-terminated string.  If the service argument is NULL or the
   servicelen argument is zero, the service name shall not be returned.
   If the service's name cannot be located, the numeric form of the
   service address (for example, its port number) shall be returned
   instead of its name.

   The arguments node and service cannot both be NULL.





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   The flags argument is a flag that changes the default actions of the
   function.  By default the fully-qualified domain name (FQDN) for the
   host shall be returned, but:

   -  If the flag bit NI_NOFQDN is set, only the node name portion of
      the FQDN shall be returned for local hosts.

   -  If the flag bit NI_NUMERICHOST is set, the numeric form of the
      host's address shall be returned instead of its name, under all
      circumstances.

   -  If the flag bit NI_NAMEREQD is set, an error shall be returned if
      the host's name cannot be located.

   -  If the flag bit NI_NUMERICSERV is set, the numeric form of the
      service address shall be returned (for example, its port number)
      instead of its name, under all circumstances.

   -  If the flag bit NI_DGRAM is set, this indicates that the service
      is a datagram service (SOCK_DGRAM).  The default behavior shall
      assume that the service is a stream service (SOCK_STREAM).

   Note:

   1. The NI_NUMERICxxx flags are required to support the "-n" flags
      that many commands provide.

   2. The NI_DGRAM flag is required for the few AF_INET and AF_INET6
      port numbers (for example, [512,514]) that represent differ