const std::string hotkey_base::get_name() const
{
std::string ret = "";
if (mod_ & KMOD_CTRL)
ret += "ctrl";
ret +=
(!ret.empty() && !boost::algorithm::ends_with(ret, "+") ?
"+" : "");
if (mod_ & KMOD_ALT)
ret += "alt";
ret +=
(!ret.empty() && !boost::algorithm::ends_with(ret, "+") ?
"+" : "");
if (mod_ & KMOD_SHIFT)
ret += "shift";
ret +=
(!ret.empty() && !boost::algorithm::ends_with(ret, "+") ?
"+" : "");
if (mod_ & KMOD_GUI)
#ifdef __APPLE__
ret += "cmd";
#else
ret += "win";
#endif
ret +=
(!ret.empty() && !boost::algorithm::ends_with(ret, "+") ?
"+" : "");
return ret += get_name_helper();
}
// data: Where we are in the dns payload
// payload: the entire udp payload
static char* get_name(const char* data, uint16_t data_len, const char* payload,
uint16_t payload_len, uint16_t* bytes_consumed)
{
log_trace("dns", "call to get_name, data_len: %d", data_len);
char* name = xmalloc(MAX_NAME_LENGTH);
*bytes_consumed = get_name_helper(data, data_len, payload,
payload_len, name, MAX_NAME_LENGTH - 1, 0);
if (*bytes_consumed == 0) {
free(name);
return NULL;
}
// Our memset ensured null byte.
assert(name[MAX_NAME_LENGTH - 1] == '\0');
log_trace("dns", "return success from get_name, bytes_consumed: %d, string: %s",
*bytes_consumed, name);
return name;
}
static uint16_t get_name_helper(const char* data, uint16_t data_len,
const char* payload, uint16_t payload_len, char* name,
uint16_t name_len, uint16_t recursion_level)
{
log_trace("dns", "_get_name_helper IN, datalen: %d namelen: %d recusion: %d",
data_len, name_len, recursion_level);
if (data_len == 0 || name_len == 0 || payload_len == 0) {
log_trace("dns", "_get_name_helper OUT, err. 0 length field. datalen %d namelen %d payloadlen %d",
data_len, name_len, payload_len);
return 0;
}
if (recursion_level > MAX_LABEL_RECURSION) {
log_trace("dns", "_get_name_helper OUT. ERR, MAX RECUSION");
return 0;
}
uint16_t bytes_consumed = 0;
// The start of data is either a sequence of labels or a ptr.
while(data_len > 0) {
uint8_t byte = data[0];
// Is this a pointer?
if (byte >= 0xc0) {
log_trace("dns", "_get_name_helper, ptr encountered");
// Do we have enough bytes to check ahead?
if (data_len < 2) {
log_trace("dns", "_get_name_helper OUT. ptr byte encountered. No offset. ERR.");
return 0;
}
// No. ntohs isn't needed here. It's because of
// the upper 2 bits indicating a pointer.
uint16_t offset = ((byte & 0x03) << 8) | (uint8_t)data[1];
log_trace("dns", "_get_name_helper. ptr offset 0x%x", offset);
if (offset >= payload_len) {
log_trace("dns", "_get_name_helper OUT. offset exceeded payload len %d ERR",
payload_len);
return 0;
}
// We need to add a dot if we are:
// -- Not first level recursion.
// -- have consumed bytes
if (recursion_level > 0 || bytes_consumed > 0) {
if (name_len < 1) {
log_warn("dns", "Exceeded static name field allocation.");
return 0;
}
name[0] = '.';
name++;
name_len--;
}
uint16_t rec_bytes_consumed = get_name_helper(payload + offset,
payload_len - offset, payload, payload_len, name, name_len,
recursion_level + 1);
// We are done so don't bother to increment the pointers.
if (rec_bytes_consumed == 0) {
log_trace("dns", "_get_name_helper OUT. rec level %d failed",
recursion_level);
return 0;
} else {
bytes_consumed += 2;
log_trace("dns", "_get_name_helper OUT. rec level %d success. %d rec bytes consumed. %d bytes consumed.",
recursion_level, rec_bytes_consumed, bytes_consumed);
return bytes_consumed;
}
} else if (byte == '\0') {
// don't bother with pointer incrementation. We're done.
bytes_consumed += 1;
log_trace("dns", "_get_name_helper OUT. rec level %d success. %d bytes consumed.",
recursion_level, bytes_consumed);
return bytes_consumed;
} else {
log_trace("dns", "_get_name_helper, segment 0x%hx encountered",
byte);
// We've now consumed a byte.
++data;
--data_len;
// Mark byte consumed after we check for first iteration.
// Do we have enough data left (must have null byte too)?
if ((byte+1) > data_len) {
log_trace("dns", "_get_name_helper OUT. ERR. Not enough data for segment %hd");
return 0;
}
// If we've consumed any bytes and are in a label, we're in a
// label chain. We need to add a dot.
if (bytes_consumed > 0) {
if (name_len < 1) {
log_warn("dns", "Exceeded static name field allocation.");
return 0;
}
name[0] = '.';
name++;
name_len--;
}
// Now we've consumed a byte.
++bytes_consumed;
// Did we run out of our arbitrary buffer?
if (byte > name_len) {
log_warn("dns", "Exceeded static name field allocation.");
return 0;
}
assert(data_len > 0);
memcpy(name, data, byte);
name += byte;
name_len -= byte;
data_len -= byte;
data += byte;
bytes_consumed += byte;
// Handled in the byte+1 check above.
assert(data_len > 0);
}
}
// We should never get here.
// For each byte we either have:
// -- a ptr, which terminates
// -- a null byte, which terminates
// -- a segment length which either terminates or ensures we keep looping
assert(0);
return 0;
}
