diff options
Diffstat (limited to 'src/llc.cpp')
| -rw-r--r-- | src/llc.cpp | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/src/llc.cpp b/src/llc.cpp index 2d295f86..b1609617 100644 --- a/src/llc.cpp +++ b/src/llc.cpp @@ -48,6 +48,26 @@ void gprs_llc::enqueue(struct msgb *llc_msg) msgb_enqueue(&queue, llc_msg); } +/* Put an Unconfirmed Information (UI) Dummy command, see GSM 44.064, 6.4.2.2 */ +void gprs_llc::put_dummy_frame(size_t req_len) +{ + /* The shortest dummy command (the spec requests at least 6 octets) */ + static const uint8_t llc_dummy_command[] = { + 0x43, 0xc0, 0x01, 0x2b, 0x2b, 0x2b + }; + static const int max_dummy_command_len = 79; + + put_frame(llc_dummy_command, sizeof(llc_dummy_command)); + + if (req_len > max_dummy_command_len) + req_len = max_dummy_command_len; + + /* Add further stuffing, if the requested length exceeds the minimum + * dummy command length */ + while (m_length < req_len) + frame[m_length++] = 0x2b; +} + void gprs_llc::put_frame(const uint8_t *data, size_t len) { /* only put frames when we are empty */ |