Hi Marcel,
On Wed, Jul 26, 2017 at 12:06 PM, Luiz Augusto von Dentz
<luiz.dentz@xxxxxxxxx> wrote:
> From: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>
>
> This uses a BPF filter to filter packets to specific index.
> ---
> monitor/control.c | 36 ++++++++++++++++++++++++++++++++++++
> monitor/control.h | 1 +
> monitor/packet.c | 9 ++-------
> 3 files changed, 39 insertions(+), 7 deletions(-)
>
> diff --git a/monitor/control.c b/monitor/control.c
> index 9bbdc37dc..05cfc3aaa 100644
> --- a/monitor/control.c
> +++ b/monitor/control.c
> @@ -28,6 +28,7 @@
>
> #include <stdio.h>
> #include <stdbool.h>
> +#include <stddef.h>
> #include <errno.h>
> #include <unistd.h>
> #include <stdlib.h>
> @@ -39,6 +40,7 @@
> #include <sys/stat.h>
> #include <termios.h>
> #include <fcntl.h>
> +#include <linux/filter.h>
>
> #include "lib/bluetooth.h"
> #include "lib/hci.h"
> @@ -58,6 +60,7 @@
> static struct btsnoop *btsnoop_file = NULL;
> static bool hcidump_fallback = false;
> static bool decode_control = true;
> +static uint16_t filter_index = HCI_DEV_NONE;
>
> struct control_data {
> uint16_t channel;
> @@ -1028,6 +1031,31 @@ static int open_socket(uint16_t channel)
> return fd;
> }
>
> +static void attach_index_filter(int fd, uint16_t index)
> +{
> + struct sock_filter filters[] = {
> + /* A <- MGMT index */
> + BPF_STMT(BPF_LD + BPF_B + BPF_ABS,
> + offsetof(struct mgmt_hdr, index)),
> + /* A == HCI_DEV_NONE */
> + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, HCI_DEV_NONE, 0, 1),
> + /* return */
> + BPF_STMT(BPF_RET|BPF_K, 0x0fffffff), /* pass */
> + /* A == index */
> + BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, index, 0, 1),
> + /* returns */
> + BPF_STMT(BPF_RET|BPF_K, 0x0fffffff), /* pass */
> + BPF_STMT(BPF_RET|BPF_K, 0), /* reject */
> + };
> + struct sock_fprog fprog = {
> + .len = sizeof(filters) / sizeof(filters[0]),
> + /* casting const away: */
> + .filter = filters,
> + };
> +
> + setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &fprog, sizeof(fprog));
> +}
> +
> static int open_channel(uint16_t channel)
> {
> struct control_data *data;
> @@ -1045,6 +1073,9 @@ static int open_channel(uint16_t channel)
> return -1;
> }
>
> + if (filter_index != HCI_DEV_NONE)
> + attach_index_filter(data->fd, filter_index);
> +
> mainloop_add_fd(data->fd, EPOLLIN, data_callback, data, free_data);
>
> return 0;
> @@ -1459,3 +1490,8 @@ void control_disable_decoding(void)
> {
> decode_control = false;
> }
> +
> +void control_filter_index(uint16_t index)
> +{
> + filter_index = index;
> +}
> diff --git a/monitor/control.h b/monitor/control.h
> index 630a852e4..dc655a45d 100644
> --- a/monitor/control.h
> +++ b/monitor/control.h
> @@ -30,5 +30,6 @@ void control_server(const char *path);
> int control_tty(const char *path, unsigned int speed);
> int control_tracing(void);
> void control_disable_decoding(void);
> +void control_filter_index(uint16_t index);
>
> void control_message(uint16_t opcode, const void *data, uint16_t size);
> diff --git a/monitor/packet.c b/monitor/packet.c
> index 387be1dcb..cedbef1f7 100644
> --- a/monitor/packet.c
> +++ b/monitor/packet.c
> @@ -104,7 +104,6 @@ static time_t time_offset = ((time_t) -1);
> static int priority_level = BTSNOOP_PRIORITY_INFO;
> static unsigned long filter_mask = 0;
> static bool index_filter = false;
> -static uint16_t index_number = 0;
> static uint16_t index_current = 0;
>
> #define UNKNOWN_MANUFACTURER 0xffff
> @@ -259,8 +258,9 @@ void packet_select_index(uint16_t index)
> {
> filter_mask &= ~PACKET_FILTER_SHOW_INDEX;
>
> + control_filter_index(index);
> +
> index_filter = true;
> - index_number = index;
> }
>
> #define print_space(x) printf("%*c", (x), ' ');
> @@ -4039,9 +4039,6 @@ void packet_control(struct timeval *tv, struct ucred *cred,
> uint16_t index, uint16_t opcode,
> const void *data, uint16_t size)
> {
> - if (index_filter && index_number != index)
> - return;
> -
> control_message(opcode, data, size);
> }
>
> @@ -4063,8 +4060,6 @@ void packet_monitor(struct timeval *tv, struct ucred *cred,
> const char *ident;
>
> if (index != HCI_DEV_NONE) {
> - if (index_filter && index_number != index)
> - return;
> index_current = index;
> }
>
> --
> 2.13.3
ping
--
Luiz Augusto von Dentz
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