tst_getnameinfo - Translate a socket address to a node name and service location
To check that getnameinfo() can used to translate a socket address to a node name and service location.
./tst_getnameinfo [-tooloption ...] -tooloption : v6api tool option
1. The flag bit NI_NUMERICHOST is set 2. Check A: the numeric form of the host's address shall be returned 3. The flag bit NI_NUMERICSERV is set, and the port numbers is set 4. Check B: the numeric form of the service address shall be returned 5. The port numbers is set and flag is set to 0 6. Check C: service name should be returned 7. The flag bit NI_DGRAM is set, and the port numbers is set 8. Check D: service name should be returned 9. The address is the IPv6 unspecified address 10.Check E: the EAI_NONAME error should be returned 11.Both the nodename and servname are null 12.Check F: the EAI_NONAME error should be returned 13.The address family was not recognized 14.Check G: the EAI_FAMILY error should be returned 15.The address length was invalid for the specified family 16.Check H: the EAI_FAMILY error should be returned 17.The flags had an invalid value 18.Check I: the EAI_BADFLAGS error should be returned 19.An argument buffer overflowed 20.Check J: the EAI_OVERFLOW error should be returned
None
RFC 3493
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.
#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.
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 different services for UDP and TCP.
The getnameinfo() function shall be thread safe.
A zero return value for getnameinfo() indicates successful completion; a non-zero return value indicates failure.
Upon successful completion, getnameinfo() shall return the node and service names, if requested, in the buffers provided. The returned names are always null-terminated strings.
Error Return Values:
The getnameinfo() 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 had an invalid value.
[EAI_FAIL] A non-recoverable error occurred.
[EAI_FAMILY] The address family was not recognized or the address length was invalid for the specified family.
[EAI_MEMORY] There was a memory allocation failure.
[EAI_NONAME] The name does not resolve for the supplied parameters. NI_NAMEREQD is set and the host's name cannot be located, or both nodename and servname were null.
[EAI_OVERFLOW] An argument buffer overflowed.
[EAI_SYSTEM] A system error occurred. The error code can be found in errno.