"btmgmt public-address"-alternative

gistfile1.txt

#include <sys/socket.h>
#include <err.h>
#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

struct sockaddr_hci {
	sa_family_t    hci_family;
	unsigned short hci_dev;
	unsigned short hci_channel;
};

#define BTPROTO_HCI     1
#define HCI_DEV_NONE    0xffff

#define HCI_CHANNEL_CONTROL     3

struct hci_set_public_address {
	uint16_t cmd;
	uint16_t dev;
	uint16_t len;
	uint8_t addr[6];
};

struct hci_response {
	uint16_t event;
	uint16_t dev;
	uint16_t len;

	uint16_t cmd;
	uint8_t status;
};

static int hci_set_public_address(uint8_t mac_addr[6])
{
	struct hci_set_public_address pub_addr;
	struct hci_response resp;
	struct sockaddr_hci addr;
	int ret;
	int fd;
	int i;

	pub_addr.cmd = 57;
	pub_addr.dev = 0;
	pub_addr.len = 6;
	for (i = 0; i < 6; i++)
		pub_addr.addr[i] = mac_addr[5-i];

	fd = socket(PF_BLUETOOTH, SOCK_RAW | SOCK_CLOEXEC, BTPROTO_HCI);
	if (fd < 0)
		err(1, "failed to create bt hci socket");

	memset(&addr, 0, sizeof(addr));
	addr.hci_family = AF_BLUETOOTH;
	addr.hci_dev = HCI_DEV_NONE;
	addr.hci_channel = HCI_CHANNEL_CONTROL;

	if (bind(fd, (struct sockaddr *) &addr, sizeof(addr)) < 0)
		err(1, "failed to bind to hci control channel");

	ret = send(fd, &pub_addr, sizeof(pub_addr), 0);
	if (ret < 0)
		err(1, "failed to send public address request");

	for (;;) {
		ret = read(fd, &resp, sizeof(resp));
		if (ret < 0)
			err(1, "failed to read response from hci mgmt");

		switch (resp.event) {
		case 1:
		case 2:
			if (resp.cmd != 57)
				continue;

			close(fd);

			switch (resp.status) {
			case 0x0a:
				return -EBUSY;
			case 0x14:
				return -EPERM;
			default:
				return -resp.status;
			}
		default:
			printf("unknown %d\n", resp.event);
			break;
		}
	}

	close(fd);

	return -ENXIO;
}