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extmod/modlwip: Implement TCP listen/accept backlog. 

Array to hold waiting connections is in-place if backlog=1, else is a
dynamically allocated array.  Incoming connections are processed FIFO
style to maintain fairness.
This commit is contained in:
Damien George 2018-11-28 16:46:02 +11:00
parent 321d75e087
commit 4737ff8054
1 changed files with 79 additions and 23 deletions
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102
extmod/modlwip.c
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@ -272,7 +272,15 @@ typedef struct _lwip_socket_obj_t {
} pcb;
volatile union {
struct pbuf *pbuf;
struct tcp_pcb *connection;
struct {
uint8_t alloc;
uint8_t iget;
uint8_t iput;
union {
struct tcp_pcb *item; // if alloc == 0
struct tcp_pcb **array; // if alloc != 0
} tcp;
} connection;
} incoming;
mp_obj_t callback;
byte peer[4];
@ -371,13 +379,19 @@ STATIC err_t _lwip_tcp_accept(void *arg, struct tcp_pcb *newpcb, err_t err) {
lwip_socket_obj_t *socket = (lwip_socket_obj_t*)arg;
tcp_recv(newpcb, _lwip_tcp_recv_unaccepted);
if (socket->incoming.connection != NULL) {
DEBUG_printf("_lwip_tcp_accept: Tried to queue >1 pcb waiting for accept\n");
// We need to handle this better. This single-level structure makes the
// backlog setting kind of pointless. FIXME
return ERR_BUF;
// Search for an empty slot to store the new connection
struct tcp_pcb *volatile *tcp_array;
if (socket->incoming.connection.alloc == 0) {
tcp_array = &socket->incoming.connection.tcp.item;
} else {
socket->incoming.connection = newpcb;
tcp_array = socket->incoming.connection.tcp.array;
}
if (tcp_array[socket->incoming.connection.iput] == NULL) {
// Have an empty slot to store waiting connection
tcp_array[socket->incoming.connection.iput] = newpcb;
if (++socket->incoming.connection.iput >= socket->incoming.connection.alloc) {
socket->incoming.connection.iput = 0;
}
if (socket->callback != MP_OBJ_NULL) {
// Schedule accept callback to be called when lwIP is done
// with processing this incoming connection on its side and
@ -386,6 +400,9 @@ STATIC err_t _lwip_tcp_accept(void *arg, struct tcp_pcb *newpcb, err_t err) {
}
return ERR_OK;
}
DEBUG_printf("_lwip_tcp_accept: No room to queue pcb waiting for accept\n");
return ERR_BUF;
}
// Callback for inbound tcp packets.
@ -643,8 +660,15 @@ STATIC mp_obj_t lwip_socket_make_new(const mp_obj_type_t *type, size_t n_args, s
}
switch (socket->type) {
case MOD_NETWORK_SOCK_STREAM: socket->pcb.tcp = tcp_new(); break;
case MOD_NETWORK_SOCK_DGRAM: socket->pcb.udp = udp_new(); break;
case MOD_NETWORK_SOCK_STREAM:
socket->pcb.tcp = tcp_new();
socket->incoming.connection.alloc = 0;
socket->incoming.connection.tcp.item = NULL;
break;
case MOD_NETWORK_SOCK_DGRAM:
socket->pcb.udp = udp_new();
socket->incoming.pbuf = NULL;
break;
//case MOD_NETWORK_SOCK_RAW: socket->pcb.raw = raw_new(); break;
default: mp_raise_OSError(MP_EINVAL);
}
@ -669,7 +693,6 @@ STATIC mp_obj_t lwip_socket_make_new(const mp_obj_type_t *type, size_t n_args, s
}
}
socket->incoming.pbuf = NULL;
socket->timeout = -1;
socket->state = STATE_NEW;
socket->recv_offset = 0;
@ -721,6 +744,18 @@ STATIC mp_obj_t lwip_socket_listen(mp_obj_t self_in, mp_obj_t backlog_in) {
mp_raise_OSError(MP_ENOMEM);
}
socket->pcb.tcp = new_pcb;
// Allocate memory for the backlog of connections
if (backlog <= 1) {
socket->incoming.connection.alloc = 0;
socket->incoming.connection.tcp.item = NULL;
} else {
socket->incoming.connection.alloc = backlog;
socket->incoming.connection.tcp.array = m_new0(struct tcp_pcb*, backlog);
}
socket->incoming.connection.iget = 0;
socket->incoming.connection.iput = 0;
tcp_accept(new_pcb, _lwip_tcp_accept);
// Socket is no longer considered "new" for purposes of polling
@ -746,19 +781,25 @@ STATIC mp_obj_t lwip_socket_accept(mp_obj_t self_in) {
}
// accept incoming connection
if (socket->incoming.connection == NULL) {
struct tcp_pcb *volatile *incoming_connection;
if (socket->incoming.connection.alloc == 0) {
incoming_connection = &socket->incoming.connection.tcp.item;
} else {
incoming_connection = &socket->incoming.connection.tcp.array[socket->incoming.connection.iget];
}
if (*incoming_connection == NULL) {
if (socket->timeout == 0) {
mp_raise_OSError(MP_EAGAIN);
} else if (socket->timeout != -1) {
for (mp_uint_t retries = socket->timeout / 100; retries--;) {
mp_hal_delay_ms(100);
if (socket->incoming.connection != NULL) break;
if (*incoming_connection != NULL) break;
}
if (socket->incoming.connection == NULL) {
if (*incoming_connection == NULL) {
mp_raise_OSError(MP_ETIMEDOUT);
}
} else {
while (socket->incoming.connection == NULL) {
while (*incoming_connection == NULL) {
poll_sockets();
}
}
@ -769,8 +810,11 @@ STATIC mp_obj_t lwip_socket_accept(mp_obj_t self_in) {
socket2->base.type = &lwip_socket_type;
// We get a new pcb handle...
socket2->pcb.tcp = socket->incoming.connection;
socket->incoming.connection = NULL;
socket2->pcb.tcp = *incoming_connection;
if (++socket->incoming.connection.iget >= socket->incoming.connection.alloc) {
socket->incoming.connection.iget = 0;
}
*incoming_connection = NULL;
// ...and set up the new socket for it.
socket2->domain = MOD_NETWORK_AF_INET;
@ -1222,15 +1266,27 @@ STATIC mp_uint_t lwip_socket_ioctl(mp_obj_t self_in, mp_uint_t request, uintptr_
}
socket->pcb.tcp = NULL;
socket->state = _ERR_BADF;
if (socket->incoming.pbuf != NULL) {
if (!socket_is_listener) {
if (!socket_is_listener) {
if (socket->incoming.pbuf != NULL) {
pbuf_free(socket->incoming.pbuf);
} else {
// Deregister callback and abort
tcp_poll(socket->incoming.connection, NULL, 0);
tcp_abort(socket->incoming.connection);
socket->incoming.pbuf = NULL;
}
} else {
uint8_t alloc = socket->incoming.connection.alloc;
struct tcp_pcb *volatile *tcp_array;
if (alloc == 0) {
tcp_array = &socket->incoming.connection.tcp.item;
} else {
tcp_array = socket->incoming.connection.tcp.array;
}
for (uint8_t i = 0; i < alloc; ++i) {
// Deregister callback and abort
if (tcp_array[i] != NULL) {
tcp_poll(tcp_array[i], NULL, 0);
tcp_abort(tcp_array[i]);
tcp_array[i] = NULL;
}
}
socket->incoming.pbuf = NULL;
}
ret = 0;