The API allows a host application program access to the user's environment information. The st.ioctl.h file includes the TCGETCINFO and TCGETUENV ioctl operations for the tty driver:
#define BIOC (`B'<<8) #define TCGETCINFO (BIOC|20) /* get network connection info */ #define TCGETUENV (BIOC|21) /* get network user environment info */
The information is available from the adapter at any time, so there is no wait to obtain it.
You can use the ci_family field to verify the underlying protocol family. Currently, it is always CIF_INET. If the ci_family field is CIF_INET, the ci_locaddr and ci_remaddr fields are cinaddr structures. Other families would use different address structures.
The ci_service field identifies the service assigned to the connection. A host application can use this field to determine how to handle the session.
The ci_flags field provides some details of the status of the session. The only bit with a defined meaning (although others may be set) is CIF_RECONNECT. This identifies a session that held its network connection across a close-and-open sequence. This allows a host application to handle a reconnect differently than a first-time connect. For example, the host might not allow auto-login for an rlogin protocol reconnect.
The ci_locaddr and ci_remaddr fields provide the local and remote Internet address information for the session. This includes the IP address in the in_addr field and the TCP protocol port in the in_port field.
The following structures show these fields in detail:
/*
* Structure for TCGETCINFO.
*/
struct cinaddr
{
unsigned long in_addr; /* Internet address */
unsigned short in_port; /* Internet port */
unsigned short in_res[5];
};
struct cinfo
{
unsigned short ci_family; /* protocol family */
unsigned short ci_service; /* type of service */
unsigned short ci_flags; /* various flags */
unsigned short ci_res0[5];
struct cinaddr ci_locaddr; /*local address info */
struct cinaddr ci_remaddr; /* remote address info */
unsigned long ci_res1[4];
};
/* * Values for ci_family. */ #define CIF_INET 1 /* Internet family */
/* * Values for ci_service. */ #define CIS_TELNET 1 /* telnet service ID */ #define CIS_RLOGIN 2 /* rlogin service ID */ #define CIS_NOP 3 /* no-op service ID */
/* * Fields for ci_flags. */ #define CIF_RECONNECT 0x0080 /* Connection held from previous open */
The TCGETUENV ioctl information is available from the adapter a short time after the connection is established. The driver delays completion of the operation until that time. The information returned by this operation is used for administration, authentication, and setting the user's initial environment on the local host.
The definition of the operation is as follows:
/*
* Structure for TCGETUENV operation.
* This operation uses a 512-byte buffer that is structured
* as follows:
* +------+--------+------+-----+------+--------+------+-----+-----+
* | type | length | data | ... | type | length | data | ... | ... |
* +------+--------+------+-----+------+--------+------+-----+-----+
* The length field is the number of bytes in the data field.
* The actual size of the entry might be less than this length.
* For example, the UET_TTYPE entry might have a data length of
* 40 bytes with the data set to "ansi" and the remaining 36 bytes
* set to zero. A type of value zero is used to terminate the list.
*/
struct uenv
{
unsigned char ue_type;
unsigned char ue_length;
char ue_data[512-2*sizeof(unsigned char)];
};
/* * Values for ue_type. */ define UET_WINSZ 1 /* winsize structure */ #define UET_TTYPE 2 /* Terminal type */ #define UET_STDERR 3 /* Standard error port ID */ #define UET_REMUSR 4 /* Remote user name */ #define UET_LOCUSR 5 /* Local user name */ #define UET_ISPEED 6 /* Input terminal baud */ #define UET_OSPEED 7 /* Output terminal baud */ #define UET_XDISPLOC 8 /* X display location */
The host uses the TCGETUENV operation to retrieve the environment information for a channel. This operation returns all of the environment information. Each entry has a two-byte header that specifies the environment type in the first byte and the length of the entry in the second byte. This operation allows a host application access to the remote user's environment. The nop service never has any environment information. The following are the defined environment types: