// Helper function for send/sendto to handle TCP packets
STATIC mp_uint_t lwip_tcp_send(lwip_socket_obj_t *socket, const byte *buf, mp_uint_t len, int *_errno) {
// Check for any pending errors
STREAM_ERROR_CHECK(socket);
u16_t available = tcp_sndbuf(socket->pcb.tcp);
if (available == 0) {
// Non-blocking socket
if (socket->timeout == 0) {
*_errno = MP_EAGAIN;
return MP_STREAM_ERROR;
}
mp_uint_t start = mp_hal_ticks_ms();
// Assume that STATE_PEER_CLOSED may mean half-closed connection, where peer closed it
// sending direction, but not receiving. Consequently, check for both STATE_CONNECTED
// and STATE_PEER_CLOSED as normal conditions and still waiting for buffers to be sent.
// If peer fully closed socket, we would have socket->state set to ERR_RST (connection
// reset) by error callback.
// Avoid sending too small packets, so wait until at least 16 bytes available
while (socket->state >= STATE_CONNECTED && (available = tcp_sndbuf(socket->pcb.tcp)) < 16) {
if (socket->timeout != -1 && mp_hal_ticks_ms() - start > socket->timeout) {
*_errno = MP_ETIMEDOUT;
return MP_STREAM_ERROR;
}
poll_sockets();
}
// While we waited, something could happen
STREAM_ERROR_CHECK(socket);
}
u16_t write_len = MIN(available, len);
err_t err = tcp_write(socket->pcb.tcp, buf, write_len, TCP_WRITE_FLAG_COPY);
// If the output buffer is getting full then send the data to the lower layers
if (err == ERR_OK && tcp_sndbuf(socket->pcb.tcp) < TCP_SND_BUF / 4) {
err = tcp_output(socket->pcb.tcp);
}
if (err != ERR_OK) {
*_errno = error_lookup_table[-err];
return MP_STREAM_ERROR;
}
return write_len;
}
// Helper function for recv/recvfrom to handle TCP packets
STATIC mp_uint_t lwip_tcp_receive(lwip_socket_obj_t *socket, byte *buf, mp_uint_t len, int *_errno) {
// Check for any pending errors
STREAM_ERROR_CHECK(socket);
if (socket->incoming.pbuf == NULL) {
// Non-blocking socket
if (socket->timeout == 0) {
if (socket->state == STATE_PEER_CLOSED) {
return 0;
}
*_errno = MP_EAGAIN;
return -1;
}
mp_uint_t start = mp_hal_ticks_ms();
while (socket->state == STATE_CONNECTED && socket->incoming.pbuf == NULL) {
if (socket->timeout != -1 && mp_hal_ticks_ms() - start > socket->timeout) {
*_errno = MP_ETIMEDOUT;
return -1;
}
poll_sockets();
}
if (socket->state == STATE_PEER_CLOSED) {
if (socket->incoming.pbuf == NULL) {
// socket closed and no data left in buffer
return 0;
}
} else if (socket->state != STATE_CONNECTED) {
assert(socket->state < 0);
*_errno = error_lookup_table[-socket->state];
return -1;
}
}
assert(socket->pcb.tcp != NULL);
struct pbuf *p = socket->incoming.pbuf;
if (socket->leftover_count == 0) {
socket->leftover_count = p->tot_len;
}
u16_t result = pbuf_copy_partial(p, buf, ((socket->leftover_count >= len) ? len : socket->leftover_count), (p->tot_len - socket->leftover_count));
if (socket->leftover_count > len) {
// More left over...
socket->leftover_count -= len;
} else {
pbuf_free(p);
socket->incoming.pbuf = NULL;
socket->leftover_count = 0;
}
tcp_recved(socket->pcb.tcp, result);
return (mp_uint_t) result;
}
// Helper function for recv/recvfrom to handle TCP packets
STATIC mp_uint_t lwip_tcp_receive(lwip_socket_obj_t *socket, byte *buf, mp_uint_t len, int *_errno) {
// Check for any pending errors
STREAM_ERROR_CHECK(socket);
if (socket->incoming.pbuf == NULL) {
// Non-blocking socket
if (socket->timeout == 0) {
if (socket->state == STATE_PEER_CLOSED) {
return 0;
}
*_errno = MP_EAGAIN;
return -1;
}
mp_uint_t start = mp_hal_ticks_ms();
while (socket->state == STATE_CONNECTED && socket->incoming.pbuf == NULL) {
if (socket->timeout != -1 && mp_hal_ticks_ms() - start > socket->timeout) {
*_errno = MP_ETIMEDOUT;
return -1;
}
poll_sockets();
}
if (socket->state == STATE_PEER_CLOSED) {
if (socket->incoming.pbuf == NULL) {
// socket closed and no data left in buffer
return 0;
}
} else if (socket->state != STATE_CONNECTED) {
assert(socket->state < 0);
*_errno = error_lookup_table[-socket->state];
return -1;
}
}
assert(socket->pcb.tcp != NULL);
struct pbuf *p = socket->incoming.pbuf;
mp_uint_t remaining = p->len - socket->recv_offset;
if (len > remaining) {
len = remaining;
}
memcpy(buf, (byte*)p->payload + socket->recv_offset, len);
remaining -= len;
if (remaining == 0) {
socket->incoming.pbuf = p->next;
// If we don't ref here, free() will free the entire chain,
// if we ref, it does what we need: frees 1st buf, and decrements
// next buf's refcount back to 1.
pbuf_ref(p->next);
pbuf_free(p);
socket->recv_offset = 0;
} else {
socket->recv_offset += len;
}
tcp_recved(socket->pcb.tcp, len);
return len;
}
