BLUETOOTH(3)

NAME
bt_gethostbyname, bt_gethostbyaddr, bt_gethostent, bt_sethostent, bt_endhostent, bt_getprotobyname, bt_getprotobynumber, bt_getprotoent, bt_setprotoent, bt_endprotoent, bt_aton, bt_ntoa, bt_devaddr, bt_devname, bt_devinfo, bt_devenum, bt_devopen, bt_devclose, bt_devsend, bt_devrecv, bt_devreq, bt_devfilter, bt_devfilter_pkt_set, bt_devfilter_pkt_clr, bt_devfilter_pkt_tst, bt_devfilter_evt_set, bt_devfilter_evt_clr, bt_devfilter_evt_tst, bt_devinquiry, bdaddr_same, bdaddr_any, bdaddr_copy - Bluetooth routines

LIBRARY
libbluetooth

SYNOPSIS
#include <bluetooth.h>
struct hostent *
bt_gethostbyname(const char *name);
struct hostent *
bt_gethostbyaddr(const char *addr, int len, int type);
struct hostent *
bt_gethostent(void);
void
bt_sethostent(int stayopen);
void
bt_endhostent(void);
struct protoent *
bt_getprotobyname(const char *name);
struct protoent *
bt_getprotobynumber(int proto);
struct protoent *
bt_getprotoent(void);
void
bt_setprotoent(int stayopen);
void
bt_endprotoent(void);
int
bt_aton(const char *str, bdaddr_t *ba);
const char *
bt_ntoa(const bdaddr_t *ba, char *str);
int
bt_devaddr(const char *devname, bdaddr_t *addr);
int
bt_devname(char *devname, const bdaddr_t *addr);
int
(bt_devenum_cb_t)(int s, struct bt_devinfo const *di, void *arg);
int
bt_devinfo(struct bt_devinfo *di);
int
bt_devenum(bt_devenum_cb_t *cb, void *arg);
int
bt_devopen(char const *devname);
int
bt_devclose(int s);
int
bt_devsend(int s, uint16_t opcode, void *param, size_t plen);
ssize_t
bt_devrecv(int s, void *buf, size_t size, time_t to);
int
bt_devreq(int s, struct bt_devreq *r, time_t to);
int
bt_devfilter(int s, struct bt_devfilter const *new, struct bt_devfilter *old);
void
bt_devfilter_pkt_set(struct bt_devfilter *filter, uint8_t type);
void
bt_devfilter_pkt_clt(struct bt_devfilter *filter, uint8_t type);
int
bt_devfilter_pkt_tst(struct bt_devfilter const *filter, uint8_t type);
void
bt_devfilter_evt_set(struct bt_devfilter *filter, uint8_t event);
void
bt_devfilter_evt_clt(struct bt_devfilter *filter, uint8_t event);
int
bt_devfilter_evt_tst(struct bt_devfilter const *filter, uint8_t event);
int
bt_devinquiry(char const *devname, time_t length, int num_rsp, struct bt_devinquiry **ii);
int
bdaddr_same(const bdaddr_t *a, const bdaddr_t *b);
int
bdaddr_any(const bdaddr_t *a);
int
bdaddr_copy(const bdaddr_t *dst, const bdaddr_t *src);

DESCRIPTION
The bt_gethostent(), bt_gethostbyname() and bt_gethostbyaddr() functions each return a pointer to an object with the hostent structure describing a Bluetooth host referenced by name or by address, respectively.

The name argument passed to bt_gethostbyname() should point to a NUL-terminated hostname. The addr argument passed to bt_gethostbyaddr() should point to an address which is len bytes long, in binary form (i.e., not a Bluetooth BD_ADDR in human readable ASCII form). The type argument specifies the address family of this address and must be set to AF_BLUETOOTH.

The structure returned contains the information obtained from a line in /etc/bluetooth/hosts file.

The bt_sethostent() function controls whether /etc/bluetooth/hosts file should stay open after each call to bt_gethostbyname() or bt_gethostbyaddr(). If the stayopen flag is non-zero, the file will not be closed.

The bt_endhostent() function closes the /etc/bluetooth/hosts file.

The bt_getprotoent(), bt_getprotobyname() and bt_getprotobynumber() functions each return a pointer to an object with the protoent structure describing a Bluetooth Protocol Service Multiplexor referenced by name or number, respectively.

The name argument passed to bt_getprotobyname() should point to a NUL-terminated Bluetooth Protocol Service Multiplexor name. The proto argument passed to bt_getprotobynumber() should have numeric value of the desired Bluetooth Protocol Service Multiplexor.

The structure returned contains the information obtained from a line in /etc/bluetooth/protocols file.

The bt_setprotoent() function controls whether /etc/bluetooth/protocols file should stay open after each call to bt_getprotobyname() or bt_getprotobynumber(). If the stayopen flag is non-zero, the file will not be closed.

The bt_endprotoent() function closes the /etc/bluetooth/protocols file.

The bt_aton() routine interprets the specified character string as a Bluetooth address, placing the address into the structure provided. It returns 1 if the string was successfully interpreted, or 0 if the string is invalid.

The routine bt_ntoa() takes a Bluetooth address and places an ASCII string representing the address into the buffer provided. It is up to the caller to ensure that provided buffer has enough space. If no buffer was provided then internal static buffer will be used.

The bt_devaddr() function interprets the specified devname string as the address or device name of a Bluetooth device on the local system, and places the device address in the provided bdaddr, if any. The function returns 1 if the string was successfully interpreted, or 0 if the string did not match any local device. The bt_devname() function takes a Bluetooth device address and copies the local device name associated with that address into the buffer provided, if any. Caller must ensure that provided buffer is at least HCI_DEVNAME_SIZE characters in size. The function returns 1 when the device was found, otherwise 0.

The bt_devinfo() function populates provided bt_devinfo structure with the information about given Bluetooth device. The caller is expected to pass Bluetooth device name in the devname field of the passed bt_devinfo structure. The function returns 0 when successful, otherwise -1. The bt_devinfo structure is defined as follows

    struct bt_devinfo
    {
            char            devname[HCI_DEVNAME_SIZE];
            uint32_t        state;
            bdaddr_t        bdaddr;
            uint16_t        _reserved0;
            uint8_t         features[HCI_DEVFEATURES_SIZE];
            /* buffer info */
            uint16_t        _reserved1;
            uint16_t        cmd_free;
            uint16_t        sco_size;
            uint16_t        sco_pkts;
            uint16_t        sco_free;
            uint16_t        acl_size;
            uint16_t        acl_pkts;
            uint16_t        acl_free;
            /* stats */
            uint32_t        cmd_sent;
            uint32_t        evnt_recv;
            uint32_t        acl_recv;
            uint32_t        acl_sent;
            uint32_t        sco_recv;
            uint32_t        sco_sent;
            uint32_t        bytes_recv;
            uint32_t        bytes_sent;
            /* misc/specific */
            uint16_t        link_policy_info;
            uint16_t        packet_type_info;
            uint16_t        role_switch_info;
            uint16_t        debug;
            uint8_t         _padding[20];
    };

The bt_devenum() function enumerates Bluetooth devices present in the system. For every device found, the function will call provided cb callback function which should be of bt_devenum_cb_t type. The callback function is passed a HCI socket s, fully populated bt_devinfo structure di and arg argument provided to the bt_devenum(). The callback function can stop enumeration by returning a value that is greater than zero. The function returns number of successfully enumerated devices, or -1 if an error occurred.

The bt_devopen() function opens a Bluetooth device with the given devname and returns a connected and bound HCI socket handle. The function returns -1 if an error has occurred.

The bt_devclose() closes the passed HCI socket handle s, previously obtained with bt_devopen(3).

The bt_devsend() function sends a Bluetooth HCI command with the given opcode to the provided socket s, previously obtained with bt_devopen(3). The opcode parameter is expected to be in the host byte order. The param and plen parameters specify command parameters. The bt_devsend() function does not modify the HCI filter on the provided socket s. The function returns 0 on success, or -1 if an error occurred.

The bt_devrecv() function receives one Bluetooth HCI packet from the socket s, previously obtained with bt_devopen(3). The packet is placed into the provided buffer buf of size size. The to parameter specifies receive timeout in seconds. Infinite timeout can be specified by passing negative value in the to parameter. The bt_devrecv() function does not modify the HCI filter on the provided socket s. The function returns total number of bytes received, or -1 if an error occurred.

The bt_devreq() function makes a Bluetooth HCI request to the socket s, previously obtained with bt_devopen(3). The function will send the specified command and will wait for the specified event, or timeout to seconds to occur. The bt_devreq structure is defined as follows

    struct bt_devreq
    {
            uint16_t        opcode;
            uint8_t         event;
            void            *cparam;
            size_t          clen;
            void            *rparam;
            size_t          rlen;
    };

The opcode field specifies the command and is expected to be in the host byte order. The cparam and clen fields specify command parameters data and command parameters data size respectively. The event field specifies which Bluetooth HCI event ID the function should wait for, otherwise it should be set to zero. The HCI Command Complete and Command Status events are enabled by default. The rparam and rlen parameters specify buffer and buffer size respectively where return parameters should be placed. The bt_devreq() function temporarily modifies filter on the provided HCI socket s. The function returns 0 on success, or -1 if an error occurred.

The bt_devfilter() controls the local HCI filter associated with the socket s, previously obtained with bt_devopen(3). Filtering can be done on packet types, i.e. ACL, SCO or HCI, command and event packets, and, in addition, on HCI event IDs. Before applying the new filter (if provided) the function will try to obtain the current filter from the socket s and place it into the old parameter (if provided). The function returns 0 on success, or -1 if an error occurred.

The bt_devfilter_pkt_set(), bt_devfilter_pkt_clr() and bt_devfilter_pkt_tst() functions can be used to modify and test the HCI filter filter. The type parameter specifies HCI packet type.

The bt_devfilter_evt_set(), bt_devfilter_evt_clr() and bt_devfilter_evt_tst() functions can be used to modify and test the HCI event filter filter. The event parameter specifies HCI event ID.

The bt_devinquiry() function performs Bluetooth inquiry. The devname parameter specifies which local Bluetooth device should perform an inquiry. If not specified, i.e. NULL, then first available device will be used. The length parameters specifies the total length of an inquiry in seconds. If not specified, i.e. 0, default value will be used. The num_rsp parameter specifies the number of responses that can be received before the inquiry is halted. If not specified, i.e. 0, default value will be used. The ii parameter specifies where to place inquiry results. On success, the function will return total number of inquiry results, will allocate, using calloc(3), buffer to store all the inquiry results and will return pointer to the allocated buffer in the ii parameter. It is up to the caller of the function to dispose of the buffer using free(3) call. The function returns -1 if an error has occurred. The bt_devinquiry structure is defined as follows

    struct bt_devinquiry {
            bdaddr_t        bdaddr;
            uint8_t         pscan_rep_mode;
            uint8_t         pscan_period_mode;
            uint8_t         dev_class[3];
            uint16_t        clock_offset;
            int8_t          rssi;
            uint8_t         data[240];
    };

The bdaddr_same(), bdaddr_any() and bdaddr_copy() are handy shorthand Bluetooth address utility functions. The bdaddr_same() function will test if two provided BD_ADDRs are the same. The bdaddr_any() function will test if provided BD_ADDR is ANY BD_ADDR. The bdaddr_copy() function will copy provided src BD_ADDR into provided dst BD_ADDR.

FILES
/etc/bluetooth/hosts
/etc/bluetooth/protocols

EXAMPLES
Print out the hostname associated with a specific BD_ADDR:

    const char *bdstr = "00:01:02:03:04:05";
    bdaddr_t bd;
    struct hostent *hp;
    if (!bt_aton(bdstr, &bd))
    	errx(1, "can't parse BD_ADDR %s", bdstr);
    if ((hp = bt_gethostbyaddr((const char *)&bd,
        sizeof(bd), AF_BLUETOOTH)) == NULL)
    	errx(1, "no name associated with %s", bdstr);
    printf("name associated with %s is %s\n", bdstr, hp->h_name);

DIAGNOSTICS
Error return status from bt_gethostent(), bt_gethostbyname() and bt_gethostbyaddr() is indicated by return of a NULL pointer. The external integer h_errno may then be checked to see whether this is a temporary failure or an invalid or unknown host. The routine herror(3) can be used to print an error message describing the failure. If its argument string is non-NULL, it is printed, followed by a colon and a space. The error message is printed with a trailing newline.

The variable h_errno can have the following values:

HOST_NOT_FOUND
    No such host is known.

NO_RECOVERY
    Some unexpected server failure was encountered. This is a non-recoverable error.

The bt_getprotoent(), bt_getprotobyname() and bt_getprotobynumber() return NULL on EOF or error.

SEE ALSO
gethostbyaddr(3), gethostbyname(3), getprotobyname(3), getprotobynumber(3), herror(3), inet_aton(3), inet_ntoa(3), ng_hci(4)

CAVEAT
The bt_gethostent() function reads the next line of /etc/bluetooth/hosts, opening the file if necessary.

The bt_sethostent() function opens and/or rewinds the /etc/bluetooth/hosts file.

The bt_getprotoent() function reads the next line of /etc/bluetooth/protocols, opening the file if necessary.

The bt_setprotoent() function opens and/or rewinds the /etc/bluetooth/protocols file.

The bt_devenum() function enumerates up to HCI_DEVMAX Bluetooth devices. During enumeration the bt_devenum() function uses the same HCI socket. The function guarantees that the socket, passed to the callback function, will be bound and connected to the Bluetooth device being enumerated.

AUTHORS
Maksim Yevmenkin <m_evmenkin@yahoo.com>

BUGS
Some of those functions use static data storage; if the data is needed for future use, it should be copied before any subsequent calls overwrite it.