Hi Arman,
> This patch adds support for connection establishment with different security
> levels. Currently, only LE connections are supported.
> ---
> tools/btgatt-client.c | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 96 insertions(+), 1 deletion(-)
>
> diff --git a/tools/btgatt-client.c b/tools/btgatt-client.c
> index a5ce70b..914b263 100644
> --- a/tools/btgatt-client.c
> +++ b/tools/btgatt-client.c
> @@ -28,15 +28,20 @@
> #include <stdbool.h>
> #include <stdint.h>
> #include <stdlib.h>
> +#include <unistd.h>
> #include <getopt.h>
> #include <limits.h>
> +#include <errno.h>
>
> #include <bluetooth/bluetooth.h>
> #include <bluetooth/hci.h>
> #include <bluetooth/hci_lib.h>
> +#include <bluetooth/l2cap.h>
>
> #include "monitor/mainloop.h"
>
> +#define ATT_CID 4
> +
> static bool verbose = false;
>
> static void print_prompt(void)
> @@ -65,6 +70,91 @@ static void prompt_read_cb(int fd, uint32_t events, void *user_data)
> free(line);
> }
>
> +static int l2cap_set_lm(int sock, int level)
> +{
> + int lm_map[] = {
> + 0,
> + L2CAP_LM_AUTH,
> + L2CAP_LM_AUTH | L2CAP_LM_ENCRYPT,
> + L2CAP_LM_AUTH | L2CAP_LM_ENCRYPT | L2CAP_LM_SECURE,
> + }, opt = lm_map[level];
> +
> + if (setsockopt(sock, SOL_L2CAP, L2CAP_LM, &opt, sizeof(opt)) < 0)
> + return -errno;
> +
> + return 0;
> +}
can we please use BT_SECURITY option instead of the link mode. You have dug out something from 13 years ago now. I do not think that we have a kernel with LE support that does not support BT_SECURITY. So such a fallback will never be triggered.
> +
> +static int l2cap_le_att_connect(bdaddr_t *src, bdaddr_t *dst, uint8_t dst_type,
> + int sec)
> +{
> + int sock;
> + struct sockaddr_l2 srcaddr, dstaddr;
> + struct bt_security btsec;
> +
> + if (verbose) {
> + char srcaddr_str[18], dstaddr_str[18];
> +
> + ba2str(src, srcaddr_str);
> + ba2str(dst, dstaddr_str);
> +
> + printf("Opening L2CAP LE connection on ATT channel:\n"
> + "\t src: %s\n\tdest: %s\n",
> + srcaddr_str, dstaddr_str);
> + }
> +
> + sock = socket(PF_BLUETOOTH, SOCK_SEQPACKET, BTPROTO_L2CAP);
> + if (sock < 0) {
> + perror("Failed to create L2CAP socket");
> + return -1;
> + }
> +
> + /* Set up source address */
> + memset(&srcaddr, 0, sizeof(srcaddr));
> + srcaddr.l2_family = AF_BLUETOOTH;
> + srcaddr.l2_cid = htobs(ATT_CID);
> + srcaddr.l2_bdaddr_type = BDADDR_LE_PUBLIC;
This one is dangerous if you end up with a LE only controller that does not have a public address.
> + bacpy(&srcaddr.l2_bdaddr, src);
I wonder if specifying BDADDR_ANY and bdaddr_type == 0 does the right thing here. There is one hole that we punched into the kernel checks for bind.
> +
> + if (bind(sock, (struct sockaddr *)&srcaddr, sizeof(srcaddr)) < 0) {
> + perror("Failed to bind L2CAP socket");
> + close(sock);
> + return -1;
> + }
> +
> + /* Set the security level */
> + memset(&btsec, 0, sizeof(btsec));
> + btsec.level = sec;
> + if (setsockopt(sock, SOL_BLUETOOTH, BT_SECURITY, &btsec,
> + sizeof(btsec)) != 0) {
> + if (l2cap_set_lm(sock, sec) < 0) {
> + fprintf(stderr, "Failed to set L2CAP security level\n");
> + close(sock);
> + return -1;
> + }
> + }
> +
> + /* Set up destination address */
> + memset(&dstaddr, 0, sizeof(dstaddr));
> + dstaddr.l2_family = AF_BLUETOOTH;
> + dstaddr.l2_cid = htobs(ATT_CID);
> + dstaddr.l2_bdaddr_type = dst_type;
> + bacpy(&dstaddr.l2_bdaddr, dst);
> +
> + printf("Connecting to device...");
> + fflush(stdout);
> +
> + if (connect(sock, (struct sockaddr *) &dstaddr, sizeof(dstaddr)) < 0) {
> + perror(" Failed to connect");
> + close(sock);
> + return -1;
> + }
> +
> + printf(" Done\n");
> +
> + return sock;
> +}
> +
> static void usage(void)
> {
> printf("btgatt-client\n");
> @@ -95,12 +185,13 @@ static struct option main_options[] = {
> int main(int argc, char *argv[])
> {
> int opt;
> - int sec;
> + int sec = 0;
> uint16_t mtu = 0;
> uint8_t dst_type = BDADDR_LE_PUBLIC;
> bool dst_addr_given = false;
> bdaddr_t src_addr, dst_addr;
> int dev_id = -1;
> + int fd;
>
> while ((opt = getopt_long(argc, argv, "+hvs:m:t:d:i:",
> main_options, NULL)) != -1) {
> @@ -203,6 +294,10 @@ int main(int argc, char *argv[])
>
> mainloop_init();
>
> + fd = l2cap_le_att_connect(&src_addr, &dst_addr, dst_type, sec);
> + if (fd < 0)
> + return EXIT_FAILURE;
> +
> if (mainloop_add_fd(fileno(stdin),
> EPOLLIN | EPOLLRDHUP | EPOLLHUP | EPOLLERR,
> prompt_read_cb, NULL, NULL) < 0) {
Regards
Marcel
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