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monitor/att: Add support for decoding GATT Long Reads
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This adds support for decoding GATT Long Reads:

< ACL Data TX: Handle 3585 flags 0x00 dlen 7
      ATT: Read Request (0x0a) len 2
        Handle: 0x0028 Type: Report Map (0x2a4b)
> ACL Data RX: Handle 3585 flags 0x02 dlen 27
      ATT: Read Response (0x0b) len 22
        Value[22]: 05010902a10185020901a10095107501150025010509
        Long Value[22]: 05010902a10185020901a10095107501150025010509
< ACL Data TX: Handle 3585 flags 0x00 dlen 9
      ATT: Read Blob Request (0x0c) len 4
        Handle: 0x0028 Type: Report Map (0x2a4b)
        Offset: 0x0016
> ACL Data RX: Handle 3585 flags 0x02 dlen 27
      ATT: Read Blob Response (0x0d) len 22
        Value[22]: 19012910810205011601f826ff07750c950209300931
        Long Value[44]: 05010902a10185020901a1009510750115002501050919
                        012910810205011601f826ff07750c950209300931
< ACL Data TX: Handle 3585 flags 0x00 dlen 9
      ATT: Read Blob Request (0x0c) len 4
        Handle: 0x0028 Type: Report Map (0x2a4b)
        Offset: 0x002c
> ACL Data RX: Handle 3585 flags 0x02 dlen 27
      ATT: Read Blob Response (0x0d) len 22
        Value[22]: 81061581257f75089501093881069501050c0a380281
        Long Value[66]: 05010902a10185020901a1009510750115002501050919
                        012910810205011601f826ff07750c9502093009318106
                        1581257f75089501
< ACL Data TX: Handle 3585 flags 0x00 dlen 9
      ATT: Read Blob Request (0x0c) len 4
        Handle: 0x0028 Type: Report Map (0x2a4b)
        Offset: 0x0042
> ACL Data RX: Handle 3585 flags 0x02 dlen 27
      ATT: Read Blob Response (0x0d) len 22
        Value[22]: 06c0c00643ff0a0202a101851175089513150026ff00
        Long Value[88]: 05010902a10185020901a1009510750115002501050919
                        012910810205011601f826ff07750c9502093009318106
                        1581257f75089501093881069501050c0a38028106c0c0
                        0643ff0a0202a101851175089513150026ff00
< ACL Data TX: Handle 3585 flags 0x00 dlen 9
      ATT: Read Blob Request (0x0c) len 4
        Handle: 0x0028 Type: Report Map (0x2a4b)
        Offset: 0x0058
> ACL Data RX: Handle 3585 flags 0x02 dlen 14
      ATT: Read Blob Response (0x0d) len 9
        Value[9]: 0902810009029100c0
        Handle: 0x0028 Type: Report Map (0x2a4b)
        Value[97]: 05010902a10185020901a1009510750115002501050919
                   012910810205011601f826ff07750c9502093009318106
                   1581257f75089501093881069501050c0a38028106c0c0
                   0643ff0a0202a101851175089513150026ff0009028100
                   09029100c0
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@Vudentz
Vudentz committed Mar 27, 2024
1 parent e6d849f commit cd22ff6
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Showing 2 changed files with 108 additions and 19 deletions.
125 changes: 107 additions & 18 deletions monitor/att.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -46,10 +46,12 @@
#include "keys.h"

struct att_read {
struct att_conn_data *conn;
struct gatt_db_attribute *attr;
bool in;
uint16_t chan;
void (*func)(const struct l2cap_frame *frame);
struct iovec *iov;
};

struct att_conn_data {
Expand All @@ -58,6 +60,7 @@ struct att_conn_data {
struct gatt_db *rdb;
struct timespec rdb_mtim;
struct queue *reads;
uint16_t mtu;
};

static void print_uuid(const char *label, const void *data, uint16_t size)
Expand Down Expand Up @@ -210,6 +213,15 @@ static void print_attribute(struct gatt_db_attribute *attr)
print_field("Handle: 0x%4.4x", handle);
}

static void att_read_free(struct att_read *read)
{
if (!read)
return;

util_iov_free(read->iov, 1);
free(read);
}

static void print_data_list(const char *label, uint8_t length,
const struct l2cap_frame *frame)
{
Expand All @@ -231,7 +243,7 @@ static void print_data_list(const char *label, uint8_t length,

print_hex_field("Value", frame->data, length - 2);

if (read) {
if (read && read->func) {
struct l2cap_frame f;

l2cap_frame_clone_size(&f, frame, length - 2);
Expand All @@ -244,7 +256,7 @@ static void print_data_list(const char *label, uint8_t length,
}

packet_hexdump(frame->data, frame->size);
free(read);
att_read_free(read);
}

static void print_attribute_info(uint16_t type, const void *data, uint16_t len)
Expand Down Expand Up @@ -370,7 +382,7 @@ static void att_error_response(const struct l2cap_frame *frame)
*/
if (pdu->request == 0x08 || pdu->request == 0x0a ||
pdu->request == 0x10)
free(att_get_read(frame));
att_read_free(att_get_read(frame));
}

static const struct bitfield_data chrc_prop_table[] = {
Expand Down Expand Up @@ -4095,9 +4107,23 @@ static void att_exchange_mtu_req(const struct l2cap_frame *frame)

static void att_exchange_mtu_rsp(const struct l2cap_frame *frame)
{
const struct bt_l2cap_att_exchange_mtu_rsp *pdu = frame->data;
struct packet_conn_data *conn;
struct att_conn_data *data;
uint16_t mtu;

if (!l2cap_frame_get_le16((void *)frame, &mtu)) {
print_text(COLOR_ERROR, " invalid size");
return;
}

print_field("Server RX MTU: %d", mtu);

print_field("Server RX MTU: %d", le16_to_cpu(pdu->mtu));
conn = packet_get_conn_data(frame->handle);
data = att_get_conn_data(conn);
if (!data)
return;

data->mtu = mtu;
}

static void att_find_info_req(const struct l2cap_frame *frame)
Expand Down Expand Up @@ -4261,8 +4287,6 @@ static void queue_read(const struct l2cap_frame *frame, bt_uuid_t *uuid,
}

handler = attr ? get_handler(attr) : get_handler_uuid(uuid);
if (!handler || !handler->read)
return;

conn = packet_get_conn_data(frame->handle);
data = att_get_conn_data(conn);
Expand All @@ -4273,10 +4297,11 @@ static void queue_read(const struct l2cap_frame *frame, bt_uuid_t *uuid,
data->reads = queue_new();

read = new0(struct att_read, 1);
read->conn = data;
read->attr = attr;
read->in = frame->in;
read->chan = frame->chan;
read->func = handler->read;
read->func = handler ? handler->read : NULL;

queue_push_tail(data->reads, read);
}
Expand Down Expand Up @@ -4334,31 +4359,95 @@ static void att_read_req(const struct l2cap_frame *frame)
queue_read(frame, NULL, handle);
}

static void att_read_append(struct att_read *read,
const struct l2cap_frame *frame)
{
if (!read->iov)
read->iov = new0(struct iovec, 1);
util_iov_append(read->iov, frame->data, frame->size);
}

static void att_read_func(struct att_read *read,
const struct l2cap_frame *frame)
{
att_read_append(read, frame);

print_attribute(read->attr);
print_hex_field("Value", read->iov->iov_base, read->iov->iov_len);

if (read->func) {
struct l2cap_frame f = *frame;

f.data = read->iov->iov_base;
f.size = read->iov->iov_len;

read->func(&f);
}

att_read_free(read);
}

static void att_read_rsp(const struct l2cap_frame *frame)
{
struct att_read *read;

print_hex_field("Value", frame->data, frame->size);

read = att_get_read(frame);
if (!read)
return;

print_attribute(read->attr);
print_hex_field("Value", frame->data, frame->size);

read->func(frame);
/* Check if the data size is equal to the MTU then read long procedure
* maybe used.
*/
if (frame->size == read->conn->mtu - 1) {
att_read_append(read, frame);
print_hex_field("Long Value", read->iov->iov_base,
read->iov->iov_len);
queue_push_head(read->conn->reads, read);
return;
}

free(read);
att_read_func(read, frame);
}

static void att_read_blob_req(const struct l2cap_frame *frame)
{
print_handle(frame, get_le16(frame->data), false);
print_field("Offset: 0x%4.4x", get_le16(frame->data + 2));
uint16_t handle, offset;
struct att_read *read;

if (!l2cap_frame_get_le16((void *)frame, &handle)) {
print_text(COLOR_ERROR, "invalid size");
return;
}

if (!l2cap_frame_get_le16((void *)frame, &offset)) {
print_text(COLOR_ERROR, "invalid size");
return;
}

print_handle(frame, handle, false);
print_field("Offset: 0x%4.4x", offset);

read = att_get_read(frame);
if (!read)
return;

/* Check if attribute handle and offset match so the read object shall
* be keeped.
*/
if (gatt_db_attribute_get_handle(read->attr) == handle &&
offset == read->iov->iov_len) {
queue_push_head(read->conn->reads, read);
return;
}

att_read_func(read, frame);
}

static void att_read_blob_rsp(const struct l2cap_frame *frame)
{
packet_hexdump(frame->data, frame->size);
att_read_rsp(frame);
}

static void att_read_multiple_req(const struct l2cap_frame *frame)
Expand Down Expand Up @@ -4403,7 +4492,7 @@ static void print_group_list(const char *label, uint8_t length,
print_handle_range("Handle range", frame->data);
print_uuid("UUID", frame->data + 4, length - 4);

if (read) {
if (read && read->func) {
struct l2cap_frame f;

l2cap_frame_clone_size(&f, frame, length);
Expand All @@ -4416,7 +4505,7 @@ static void print_group_list(const char *label, uint8_t length,
}

packet_hexdump(frame->data, frame->size);
free(read);
att_read_free(read);
}

static void att_read_group_type_rsp(const struct l2cap_frame *frame)
Expand Down
2 changes: 1 addition & 1 deletion monitor/display.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -87,7 +87,7 @@ static inline void print_hex_field(const char *label, const uint8_t *data,
for (i = 0; i < len; i++)
sprintf(str + (i * 2), "%2.2x", data[i]);

print_field("%s: %s", label, str);
print_field("%s[%u]: %s", label, len, str);
}

void set_default_pager_num_columns(int num_columns);
Expand Down

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