Fix gatt_read_char() so that it can correctly read an attribute longer
than (MTU-1) octets long. This is intended to be the first
use of the compound (multi-step) GATT Procedure mechanism
g_attrib_send_seq(), which will run the GATT procedure to completion
before executing any additional GATT Procedures. Functionaly, it
will check the result length of the original READ_REQ, and if
it is equal to the DEAFULT_MTU (23) octets long, it will make
a series of READ_BLOB_REQs until the entire remote attribute has
been read, after which it returns the result to the original
caller as if the data had been retrieved in a single ATT resp.
---
attrib/gatt.c | 134 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 132 insertions(+), 2 deletions(-)
diff --git a/attrib/gatt.c b/attrib/gatt.c
index bca8b49..3a89b30 100644
--- a/attrib/gatt.c
+++ b/attrib/gatt.c
@@ -97,15 +97,145 @@ guint gatt_read_char_by_uuid(GAttrib *attrib, uint16_t start, uint16_t end,
pdu, plen, func, user_data, NULL);
}
+struct read_long_data {
+ GAttrib *attrib;
+ GAttribResultFunc func;
+ gpointer user_data;
+ guint8 *buffer;
+ guint16 size;
+ guint16 handle;
+ guint id;
+ guint8 ref;
+};
+
+static void read_long_destroy(gpointer user_data)
+{
+ struct read_long_data *long_read = user_data;
+
+ if (--long_read->ref)
+ return;
+
+ if (long_read->buffer != NULL)
+ g_free(long_read->buffer);
+
+ g_free(long_read);
+}
+
+static void read_blob_helper(guint8 status, const guint8 *rpdu, guint16 rlen,
+ gpointer user_data)
+{
+ struct read_long_data *long_read = user_data;
+ uint8_t pdu[ATT_DEFAULT_MTU];
+ guint8 *tmp;
+ guint16 plen;
+ guint id;
+
+ if (status == ATT_ECODE_ATTR_NOT_LONG ||
+ status == ATT_ECODE_INVALID_OFFSET) {
+ status = 0;
+ goto done;
+ }
+
+ if (status != 0 || rlen == 1)
+ goto done;
+
+ tmp = g_try_realloc(long_read->buffer, long_read->size + rlen - 1);
+
+ if (tmp == NULL) {
+ status = ATT_ECODE_INSUFF_RESOURCES;
+ goto done;
+ }
+
+ memcpy(&tmp[long_read->size], &rpdu[1], rlen - 1);
+ long_read->buffer = tmp;
+ long_read->size += rlen - 1;
+
+ if (rlen < ATT_DEFAULT_MTU)
+ goto done;
+
+ plen = enc_read_blob_req(long_read->handle, long_read->size - 1,
+ pdu, sizeof(pdu));
+ id = g_attrib_send_seq(long_read->attrib, TRUE, long_read->id,
+ ATT_OP_READ_BLOB_REQ, pdu, plen,
+ read_blob_helper, long_read, read_long_destroy);
+
+ if (id != 0) {
+ long_read->ref++;
+ return;
+ }
+
+ status = ATT_ECODE_IO;
+
+done:
+ long_read->func(status, long_read->buffer, long_read->size,
+ long_read->user_data);
+}
+
+static void read_char_helper(guint8 status, const guint8 *rpdu,
+ guint16 rlen, gpointer user_data)
+{
+ struct read_long_data *long_read = user_data;
+ uint8_t pdu[ATT_DEFAULT_MTU];
+ guint16 plen;
+ guint id;
+
+ if (status != 0 || rlen < ATT_DEFAULT_MTU)
+ goto done;
+
+ long_read->buffer = g_malloc(rlen);
+
+ if (long_read->buffer == NULL)
+ goto done;
+
+ memcpy(long_read->buffer, rpdu, rlen);
+ long_read->size = rlen;
+
+ plen = enc_read_blob_req(long_read->handle, rlen - 1, pdu, sizeof(pdu));
+ id = g_attrib_send_seq(long_read->attrib, TRUE, long_read->id,
+ ATT_OP_READ_BLOB_REQ, pdu, plen, read_blob_helper,
+ long_read, read_long_destroy);
+
+ if (id != 0) {
+ long_read->ref++;
+ return;
+ }
+
+ status = ATT_ECODE_IO;
+
+done:
+ long_read->func(status, rpdu, rlen, long_read->user_data);
+}
+
guint gatt_read_char(GAttrib *attrib, uint16_t handle, GAttribResultFunc func,
gpointer user_data)
{
uint8_t pdu[ATT_DEFAULT_MTU];
guint16 plen;
+ guint id;
+ struct read_long_data *long_read;
+
+ long_read = g_try_new0(struct read_long_data, 1);
+
+ if (long_read == NULL)
+ return 0;
+
+ long_read->attrib = attrib;
+ long_read->func = func;
+ long_read->user_data = user_data;
+ long_read->handle = handle;
plen = enc_read_req(handle, pdu, sizeof(pdu));
- return g_attrib_send(attrib, ATT_OP_READ_REQ, pdu, plen, func,
- user_data, NULL);
+ id = g_attrib_send_seq(attrib, TRUE, 0, ATT_OP_READ_REQ, pdu, plen,
+ read_char_helper, long_read, read_long_destroy);
+
+ if (id == 0)
+ g_free(long_read);
+ else {
+ long_read->ref++;
+ long_read->id = id;
+ }
+
+ return id;
}
guint gatt_write_char(GAttrib *attrib, uint16_t handle, uint8_t *value,
--
1.7.2.2
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