diff options
| -rw-r--r-- | extmod/modlwip.c | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/extmod/modlwip.c b/extmod/modlwip.c index c7e050129..d1359a2aa 100644 --- a/extmod/modlwip.c +++ b/extmod/modlwip.c @@ -370,6 +370,43 @@ STATIC err_t _lwip_tcp_connected(void *arg, struct tcp_pcb *tpcb, err_t err) { return ERR_OK; } +// Handle errors (eg connection aborted) on TCP PCBs that have been put on the +// accept queue but are not yet actually accepted. +STATIC void _lwip_tcp_err_unaccepted(void *arg, err_t err) { + struct tcp_pcb *pcb = (struct tcp_pcb*)arg; + + // The ->connected entry is repurposed to store the parent socket; this is safe + // because it's only ever used by lwIP if tcp_connect is called on the TCP PCB. + lwip_socket_obj_t *socket = (lwip_socket_obj_t*)pcb->connected; + + // Array is not volatile because thiss callback is executed within the lwIP context + uint8_t alloc = socket->incoming.connection.alloc; + struct tcp_pcb **tcp_array = (struct tcp_pcb**)lwip_socket_incoming_array(socket); + + // Search for PCB on the accept queue of the parent socket + struct tcp_pcb **shift_down = NULL; + uint8_t i = socket->incoming.connection.iget; + do { + if (shift_down == NULL) { + if (tcp_array[i] == pcb) { + shift_down = &tcp_array[i]; + } + } else { + *shift_down = tcp_array[i]; + shift_down = &tcp_array[i]; + } + if (++i >= alloc) { + i = 0; + } + } while (i != socket->incoming.connection.iput); + + // PCB found in queue, remove it + if (shift_down != NULL) { + *shift_down = NULL; + socket->incoming.connection.iput = shift_down - tcp_array; + } +} + // By default, a child socket of listen socket is created with recv // handler which discards incoming pbuf's. We don't want to do that, // so set this handler which requests lwIP to keep pbuf's and deliver @@ -409,6 +446,15 @@ STATIC err_t _lwip_tcp_accept(void *arg, struct tcp_pcb *newpcb, err_t err) { // is idle. tcp_poll(newpcb, _lwip_tcp_accept_finished, 1); } + + // Set the error callback to handle the case of a dropped connection before we + // have a chance to take it off the accept queue. + // The ->connected entry is repurposed to store the parent socket; this is safe + // because it's only ever used by lwIP if tcp_connect is called on the TCP PCB. + newpcb->connected = (void*)socket; + tcp_arg(newpcb, newpcb); + tcp_err(newpcb, _lwip_tcp_err_unaccepted); + return ERR_OK; } |