static int bio_write(BIO *b, const char *buf, int len)
{
struct dtls_flow *tc = b->ptr;
struct mbuf *mb;
enum {SPACE = 4}; /* sizeof TURN channel header */
int err;
mb = mbuf_alloc(SPACE + len);
if (!mb)
return -1;
(void)mbuf_fill(mb, 0x00, SPACE);
(void)mbuf_write_mem(mb, (void *)buf, len);
mb->pos = SPACE;
err = udp_send_helper(tc->us, &tc->peer, mb, tc->uh);
if (err) {
warning("dtls: udp_send_helper: %m\n", err);
}
mem_deref(mb);
return err ? -1 : len;
}
/** Find the next empty write chunk, sets self->writerChunk to it and returns * it.
*
* We only use the next one if it is empty. If not, we essentially just filled
* up the last chunk and wrapped around to the socket reader. In that case, we
* either create a new chunk if the overall buffer can still grow, or we drop
* the data from the current one.
*
* \warning A lock on the current writer chunk should be held prior to calling
* this function. It will be released, and the returned writerChunk will be
* similarly locked.
*
* \param self BufferedWriter pointer
* \param current locked BufferChunk to use or from which to find the next
* \return a locked BufferChunk in which data can be stored
*/
BufferChunk*
getNextWriteChunk(BufferedWriter* self, BufferChunk* current) {
int nlost;
BufferChunk* nextBuffer;
assert(current != NULL);
nextBuffer = current->next;
oml_unlock(¤t->lock, __FUNCTION__);
assert(nextBuffer != NULL);
oml_lock(&self->lock, __FUNCTION__);
if (nextBuffer == self->nextReaderChunk) {
if (self->unallocatedBuffers > 0) {
/* The next buffer is the next to be read, but we can allocate more,
* allocate a new buffer, insert it after the current writer, and use it */
nextBuffer = createBufferChunk(self);
assert(nextBuffer); /** \todo Use existing buffer if allocation fails */
oml_unlock(&self->lock, __FUNCTION__);
oml_lock(¤t->lock, __FUNCTION__);
nextBuffer->next = current->next;
current->next = nextBuffer; /* we have a lock on this one */
oml_unlock(¤t->lock, __FUNCTION__);
oml_lock(&self->lock, __FUNCTION__);
} else {
/* The next buffer is the next to be read, and we cannot allocate more,
* use it, dropping unread data, and advance the read pointer */
self->nextReaderChunk = nextBuffer->next;
}
}
self->writerChunk = nextBuffer;
nlost = bw_msgcount_reset(self);
self->nlost += nlost;
oml_unlock(&self->lock, __FUNCTION__);
oml_lock(&nextBuffer->lock, __FUNCTION__);
if (nlost) {
logwarn("%s: Dropping %d samples (%dB)\n", self->outStream->dest, nlost, mbuf_fill(nextBuffer->mbuf));
}
mbuf_clear2(nextBuffer->mbuf, 0);
// Now we just need to copy the message from current to self->writerChunk
int msgSize = mbuf_message_length(current->mbuf);
if (msgSize > 0) {
mbuf_write(nextBuffer->mbuf, mbuf_message(current->mbuf), msgSize);
mbuf_reset_write(current->mbuf);
}
return nextBuffer;
}
static int pcp_map_encode(struct mbuf *mb, const struct pcp_map *map)
{
int err = 0;
if (!mb || !map)
return EINVAL;
err |= mbuf_write_mem(mb, map->nonce, sizeof(map->nonce));
err |= mbuf_write_u8(mb, map->proto);
err |= mbuf_fill(mb, 0x00, 3);
err |= mbuf_write_u16(mb, htons(map->int_port));
err |= pcp_write_port(mb, &map->ext_addr);
err |= pcp_ipaddr_encode(mb, &map->ext_addr);
return err;
}
// This function finds the next empty write chain, sets +self->writeChain+ to
// it and returns.
//
// We only use the next one if it is empty. If not, we
// essentially just filled up the last chain and wrapped
// around to the socket reader. In that case, we either create a new chain
// if the overall buffer can still grow, or we drop the data from the current one.
//
// This assumes that the current thread holds the +self->lock+ and the lock on
// the +self->writeChain+.
//
BufferChain*
getNextWriteChain(
BufferedWriter* self,
BufferChain* current
) {
assert(current != NULL);
BufferChain* nextBuffer = current->next;
assert(nextBuffer != NULL);
BufferChain* resChain = NULL;
if (mbuf_remaining(nextBuffer->mbuf) == 0) {
// It's empty, we can use it
mbuf_clear2(nextBuffer->mbuf, 0);
resChain = nextBuffer;
} else if (self->chainsAvailable > 0) {
// insert new chain between current and next one.
BufferChain* newBuffer = createBufferChain(self);
newBuffer->next = nextBuffer;
current->next = newBuffer;
resChain = newBuffer;
} else {
// Filled up buffer, time to drop data and reuse current buffer
// Current buffer holds most recent added data (we drop from the queue's tail
//assert(current->reading == 0);
assert(current->reading == 0);
o_log (O_LOG_WARN, "Dropping %d bytes of measurement data\n", mbuf_fill(current->mbuf));
mbuf_repack_message2(current->mbuf);
return current;
}
// Now we just need to copy the +message+ from +current+ to +resChain+
int msgSize = mbuf_message_length(current->mbuf);
if (msgSize > 0) {
mbuf_write(resChain->mbuf, mbuf_message(current->mbuf), msgSize);
mbuf_reset_write(current->mbuf);
}
return resChain;
}
/** Send data contained in one chunk.
*
* \warning This function acquires the lock on the BufferedWriter for the time
* it takes to check the double-buffer.
*
* \warning This function acquires the lock on the chunk being processed for
* the time it takes to check it and swap the double buffer.
*
* \bug The meta buffer should also be protected.
*
* \param self BufferedWriter to process
* \param chunk link of the chunk to process
*
* \return 1 if chunk has been fully sent, 0 if not, -1 on continuing back-off, -2 otherwise
* \see oml_outs_write_f
*/
static int
processChunk(BufferedWriter* self, BufferChunk* chunk)
{
time_t now;
int ret = -2;
ssize_t cnt = 0;
MBuffer *read_buf = NULL;
assert(self);
assert(self->meta_buf);
assert(self->read_buf);
assert(chunk);
assert(chunk->mbuf);
oml_lock(&self->lock, __FUNCTION__);
if (mbuf_message(self->read_buf) > mbuf_rdptr(self->read_buf)) {
/* There is unread data in the double buffer */
read_buf = self->read_buf;
}
oml_unlock(&self->lock, __FUNCTION__);
oml_lock(&chunk->lock, __FUNCTION__);
if ((NULL == read_buf) && (mbuf_message(chunk->mbuf) >= mbuf_rdptr(chunk->mbuf))) {
/* There is unread data in the read buffer, swap MBuffers */
read_buf = chunk->mbuf;
chunk->mbuf = self->read_buf;
}
oml_unlock(&chunk->lock, __FUNCTION__);
oml_lock(&self->lock, __FUNCTION__);
self->read_buf = read_buf;
oml_unlock(&self->lock, __FUNCTION__);
if (NULL == read_buf) {
/* The current message is not after the read pointer,
* we must be on the writer chunk */
ret = 1;
goto processChunk_cleanup;
}
time(&now);
if (difftime(now, self->last_failure_time) < self->backoff) {
logdebug("%s: Still in back-off period (%ds)\n", self->outStream->dest, self->backoff);
ret = -1;
goto processChunk_cleanup;
}
while (mbuf_write_offset(read_buf) > mbuf_read_offset(read_buf)) {
oml_lock(&self->meta_lock, __FUNCTION__);
cnt = self->outStream->write(self->outStream,
mbuf_rdptr(read_buf), mbuf_message_offset(read_buf) - mbuf_read_offset(read_buf),
mbuf_rdptr(self->meta_buf), mbuf_fill(self->meta_buf));
oml_unlock(&self->meta_lock, __FUNCTION__);
if (cnt > 0) {
mbuf_read_skip(read_buf, cnt);
if (self->backoff) {
self->backoff = 0;
loginfo("%s: Connected\n", self->outStream->dest);
}
} else {
self->last_failure_time = now;
if (!self->backoff) {
self->backoff = 1;
} else if (self->backoff < UINT8_MAX) {
self->backoff *= 2;
}
logwarn("%s: Error sending, backing off for %ds\n", self->outStream->dest, self->backoff);
goto processChunk_cleanup;
}
}
ret = 1;
processChunk_cleanup:
return ret;
}
