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Socket I/F: Add recvfrom() method to interface.

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This commit is contained in:
Gregory Nutt 2017-07-12 17:36:05 -06:00
parent 447785b264
commit a71c504142
13 changed files with 2296 additions and 1931 deletions
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11
include/nuttx/net/net.h
View file

@ -102,12 +102,15 @@ struct socket; /* Forward reference */
struct sock_intf_s
{
CODE int (*si_setup)(FAR struct socket *psock, int protocol);
CODE int (*si_setup)(FAR struct socket *psock, int protocol);
CODE ssize_t (*si_send)(FAR struct socket *psock, FAR const void *buf,
size_t len, int flags);
size_t len, int flags);
CODE ssize_t (*si_sendto)(FAR struct socket *psock, FAR const void *buf,
size_t len, int flags, FAR const struct sockaddr *to,
socklen_t tolen);
size_t len, int flags, FAR const struct sockaddr *to,
socklen_t tolen);
CODE ssize_t (*si_recvfrom)(FAR struct socket *psock, FAR void *buf,
size_t len, int flags, FAR struct sockaddr *from,
FAR socklen_t *fromlen);
};
/* This is the internal representation of a socket reference by a file

8
net/local/local.h
View file

@ -428,7 +428,7 @@ ssize_t psock_local_sendto(FAR struct socket *psock, FAR const void *buf,
int local_send_packet(int fd, FAR const uint8_t *buf, size_t len);
/****************************************************************************
* Name: psock_recvfrom
* Name: local_recvfrom
*
* Description:
* recvfrom() receives messages from a local socket, and may be used to
@ -455,9 +455,9 @@ int local_send_packet(int fd, FAR const uint8_t *buf, size_t len);
*
****************************************************************************/
ssize_t psock_local_recvfrom(FAR struct socket *psock, FAR void *buf,
size_t len, int flags, FAR struct sockaddr *from,
FAR socklen_t *fromlen);
ssize_t local_recvfrom(FAR struct socket *psock, FAR void *buf,
size_t len, int flags, FAR struct sockaddr *from,
FAR socklen_t *fromlen);
/****************************************************************************
* Name: local_fifo_read

17
net/local/local_recvfrom.c
View file

@ -387,11 +387,11 @@ errout_with_halfduplex:
****************************************************************************/
/****************************************************************************
* Name: psock_local_recvfrom
* Name: local_recvfrom
*
* Description:
* psock_local_recvfrom() receives messages from a local socket and may be
* used to receive data on a socket whether or not it is connection-oriented.
* local_recvfrom() receives messages from a local socket and may be used
* to receive data on a socket whether or not it is connection-oriented.
*
* If from is not NULL, and the underlying protocol provides the source
* address, this source address is filled in. The argument fromlen
@ -409,14 +409,15 @@ errout_with_halfduplex:
* Returned Value:
* On success, returns the number of characters received. If no data is
* available to be received and the peer has performed an orderly shutdown,
* recv() will return 0. Otherwise, on errors, -1 is returned, and errno
* is set appropriately (see receive from for the complete list).
* recv() will return 0. Otherwise, on errors, a negated errno value is
* returned (see recv_from() for the complete list of appropriate error
* values).
*
****************************************************************************/
ssize_t psock_local_recvfrom(FAR struct socket *psock, FAR void *buf,
size_t len, int flags, FAR struct sockaddr *from,
FAR socklen_t *fromlen)
ssize_t local_recvfrom(FAR struct socket *psock, FAR void *buf,
size_t len, int flags, FAR struct sockaddr *from,
FAR socklen_t *fromlen)
{
DEBUGASSERT(psock && psock->s_conn && buf);

19
net/local/local_sockif.c
View file

@ -70,9 +70,10 @@ static ssize_t local_sendto(FAR struct socket *psock, FAR const void *buf,
const struct sock_intf_s g_local_sockif =
{
local_setup, /* si_setup */
local_send, /* si_send */
local_sendto, /* si_sendto */
local_setup, /* si_setup */
local_send, /* si_send */
local_sendto, /* si_sendto */
local_recvfrom /* si_recvfrom */
};
/****************************************************************************
@ -183,9 +184,9 @@ static int local_setup(FAR struct socket *psock, int protocol)
* flags Send flags
*
* Returned Value:
* On success, returns the number of characters sent. On error, -1 is
* returned, and errno is set appropriately (see send() for the list of
* appropriate errors values.
* On success, returns the number of characters sent. On error, a negated
* errno value is returned (see send() for the list of appropriate error
* values.
*
****************************************************************************/
@ -245,9 +246,9 @@ static ssize_t local_send(FAR struct socket *psock, FAR const void *buf,
* tolen The length of the address structure
*
* Returned Value:
* On success, returns the number of characters sent. On error, -1 is
* returned, and errno is set appropriately (see send_to() for the list of
* appropriate errors values.
* On success, returns the number of characters sent. On error, a negated
* errno value is returned (see send_to() for the list of appropriate error
* values.
*
****************************************************************************/

1
net/pkt/Make.defs
View file

@ -41,6 +41,7 @@ ifeq ($(CONFIG_NET_PKT),y)
SOCK_CSRCS += pkt_sockif.c
SOCK_CSRCS += pkt_send.c
SOCK_CSRCS += pkt_recvfrom.c
# Transport layer

36
net/pkt/pkt.h
View file

@ -101,6 +101,7 @@ EXTERN const struct sock_intf_s g_pkt_sockif;
struct net_driver_s; /* Forward reference */
struct eth_hdr_s; /* Forward reference */
struct socket; /* Forward reference */
/****************************************************************************
* Name: pkt_initialize()
@ -201,6 +202,41 @@ uint16_t pkt_callback(FAR struct net_driver_s *dev,
/* pkt_input() is prototyped in include/nuttx/net/pkt.h */
/****************************************************************************
* Name: pkt_recvfrom
*
* Description:
* Implements the socket recvfrom interface for the case of the AF_INET
* and AF_INET6 address families. pkt_recvfrom() receives messages from
* a socket, and may be used to receive data on a socket whether or not it
* is connection-oriented.
*
* If 'from' is not NULL, and the underlying protocol provides the source
* address, this source address is filled in. The argument 'fromlen' is
* initialized to the size of the buffer associated with from, and
* modified on return to indicate the actual size of the address stored
* there.
*
* Parameters:
* psock A pointer to a NuttX-specific, internal socket structure
* buf Buffer to receive data
* len Length of buffer
* flags Receive flags
* from Address of source (may be NULL)
* fromlen The length of the address structure
*
* Returned Value:
* On success, returns the number of characters received. If no data is
* available to be received and the peer has performed an orderly shutdown,
* recv() will return 0. Otherwise, on errors, a negated errno value is
* returned (see recvfrom() for the list of appropriate error values).
*
****************************************************************************/
ssize_t pkt_recvfrom(FAR struct socket *psock, FAR void *buf, size_t len,
int flags, FAR struct sockaddr *from,
FAR socklen_t *fromlen);
/****************************************************************************
* Name: pkt_find_device
*

485
net/pkt/pkt_recvfrom.c Normal file
View file

@ -0,0 +1,485 @@
/****************************************************************************
* net/socket/pkt_recvfrom.c
*
* Copyright (C) 2007-2009, 2011-2017 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#ifdef CONFIG_NET
#include <sys/types.h>
#include <sys/socket.h>
#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <debug.h>
#include <assert.h>
#include <arch/irq.h>
#include <nuttx/clock.h>
#include <nuttx/semaphore.h>
#include <nuttx/net/net.h>
#include <nuttx/net/netdev.h>
#include "netdev/netdev.h"
#include "devif/devif.h"
#include "pkt/pkt.h"
#include "socket/socket.h"
#include <netpacket/packet.h>
/****************************************************************************
* Private Types
****************************************************************************/
struct pkt_recvfrom_s
{
FAR struct devif_callback_s *pr_cb; /* Reference to callback instance */
sem_t pr_sem; /* Semaphore signals recv completion */
size_t pr_buflen; /* Length of receive buffer */
uint8_t *pr_buffer; /* Pointer to receive buffer */
ssize_t pr_recvlen; /* The received length */
int pr_result; /* Success:OK, failure:negated errno */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: pkt_add_recvlen
*
* Description:
* Update information about space available for new data and update size
* of data in buffer, This logic accounts for the case where
* recvfrom_udpreadahead() sets state.pr_recvlen == -1 .
*
* Parameters:
* pstate recvfrom state structure
* recvlen size of new data appended to buffer
*
* Returned Value:
* None
*
****************************************************************************/
static inline void pkt_add_recvlen(FAR struct pkt_recvfrom_s *pstate,
size_t recvlen)
{
if (pstate->pr_recvlen < 0)
{
pstate->pr_recvlen = 0;
}
pstate->pr_recvlen += recvlen;
pstate->pr_buffer += recvlen;
pstate->pr_buflen -= recvlen;
}
/****************************************************************************
* Name: pkt_recvfrom_newdata
*
* Description:
* Copy the read data from the packet
*
* Parameters:
* dev The structure of the network driver that caused the interrupt
* pstate recvfrom state structure
*
* Returned Value:
* None.
*
* Assumptions:
* The network is locked.
*
****************************************************************************/
static void pkt_recvfrom_newdata(FAR struct net_driver_s *dev,
FAR struct pkt_recvfrom_s *pstate)
{
size_t recvlen;
if (dev->d_len > pstate->pr_buflen)
{
recvlen = pstate->pr_buflen;
}
else
{
recvlen = dev->d_len;
}
/* Copy the new packet data into the user buffer */
memcpy(pstate->pr_buffer, dev->d_buf, recvlen);
ninfo("Received %d bytes (of %d)\n", (int)recvlen, (int)dev->d_len);
/* Update the accumulated size of the data read */
pkt_add_recvlen(pstate, recvlen);
}
/****************************************************************************
* Name: pkt_recvfrom_sender
*
* Description:
*
* Parameters:
*
* Returned Values:
*
* Assumptions:
*
****************************************************************************/
static inline void pkt_recvfrom_sender(FAR struct net_driver_s *dev,
FAR struct pkt_recvfrom_s *pstate)
{
}
/****************************************************************************
* Name: pkt_recvfrom_interrupt
*
* Description:
*
* Parameters:
*
* Returned Values:
*
* Assumptions:
*
****************************************************************************/
static uint16_t pkt_recvfrom_interrupt(FAR struct net_driver_s *dev,
FAR void *pvconn, FAR void *pvpriv,
uint16_t flags)
{
struct pkt_recvfrom_s *pstate = (struct pkt_recvfrom_s *)pvpriv;
ninfo("flags: %04x\n", flags);
/* 'priv' might be null in some race conditions (?) */
if (pstate)
{
/* If a new packet is available, then complete the read action. */
if ((flags & PKT_NEWDATA) != 0)
{
/* Copy the packet */
pkt_recvfrom_newdata(dev, pstate);
/* We are finished. */
ninfo("PKT done\n");
/* Don't allow any further call backs. */
pstate->pr_cb->flags = 0;
pstate->pr_cb->priv = NULL;
pstate->pr_cb->event = NULL;
#if 0
/* Save the sender's address in the caller's 'from' location */
pkt_recvfrom_sender(dev, pstate);
#endif
/* indicate that the data has been consumed */
flags &= ~PKT_NEWDATA;
/* Wake up the waiting thread, returning the number of bytes
* actually read.
*/
sem_post(&pstate->pr_sem);
}
}
return flags;
}
/****************************************************************************
* Name: pkt_recvfrom_initialize
*
* Description:
* Initialize the state structure
*
* Parameters:
* psock Pointer to the socket structure for the socket
* buf Buffer to receive data
* len Length of buffer
* pstate A pointer to the state structure to be initialized
*
* Returned Value:
* None
*
* Assumptions:
*
****************************************************************************/
static void pkt_recvfrom_initialize(FAR struct socket *psock, FAR void *buf,
size_t len, FAR struct sockaddr *infrom,
FAR socklen_t *fromlen,
FAR struct pkt_recvfrom_s *pstate)
{
/* Initialize the state structure. */
memset(pstate, 0, sizeof(struct pkt_recvfrom_s));
/* This semaphore is used for signaling and, hence, should not have
* priority inheritance enabled.
*/
(void)sem_init(&pstate->pr_sem, 0, 0); /* Doesn't really fail */
(void)sem_setprotocol(&pstate->pr_sem, SEM_PRIO_NONE);
pstate->pr_buflen = len;
pstate->pr_buffer = buf;
}
/* The only un-initialization that has to be performed is destroying the
* semaphore.
*/
#define pkt_recvfrom_uninitialize(s) sem_destroy(&(s)->pr_sem)
/****************************************************************************
* Name: pkt_recvfrom_result
*
* Description:
* Evaluate the result of the recv operations
*
* Parameters:
* result The result of the net_lockedwait operation (may indicate EINTR)
* pstate A pointer to the state structure to be initialized
*
* Returned Value:
* The result of the recv operation with errno set appropriately
*
* Assumptions:
*
****************************************************************************/
static ssize_t pkt_recvfrom_result(int result, struct pkt_recvfrom_s *pstate)
{
int save_errno = get_errno(); /* In case something we do changes it */
/* Check for a error/timeout detected by the interrupt handler. Errors are
* signaled by negative errno values for the rcv length
*/
if (pstate->pr_result < 0)
{
/* This might return EAGAIN on a timeout or ENOTCONN on loss of
* connection (TCP only)
*/
return pstate->pr_result;
}
/* If net_lockedwait failed, then we were probably reawakened by a signal. In
* this case, net_lockedwait will have set errno appropriately.
*/
if (result < 0)
{
return -save_errno;
}
return pstate->pr_recvlen;
}
/****************************************************************************
* Name: pkt_recvfrom_rxnotify
*
* Description:
* Notify the appropriate device driver that we are ready to receive a
* packet (PKT)
*
* Parameters:
* conn - The PKT connection structure
*
* Returned Value:
* None
*
****************************************************************************/
#if 0 /* Not implemented */
static void pkt_recvfrom_rxnotify(FAR struct pkt_conn_s *conn)
{
# warning Missing logic
}
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: pkt_recvfrom
*
* Description:
* Implements the socket recvfrom interface for the case of the AF_INET
* and AF_INET6 address families. pkt_recvfrom() receives messages from
* a socket, and may be used to receive data on a socket whether or not it
* is connection-oriented.
*
* If 'from' is not NULL, and the underlying protocol provides the source
* address, this source address is filled in. The argument 'fromlen' is
* initialized to the size of the buffer associated with from, and
* modified on return to indicate the actual size of the address stored
* there.
*
* Parameters:
* psock A pointer to a NuttX-specific, internal socket structure
* buf Buffer to receive data
* len Length of buffer
* flags Receive flags
* from Address of source (may be NULL)
* fromlen The length of the address structure
*
* Returned Value:
* On success, returns the number of characters received. If no data is
* available to be received and the peer has performed an orderly shutdown,
* recv() will return 0. Otherwise, on errors, a negated errno value is
* returned (see recvfrom() for the list of appropriate error values).
*
****************************************************************************/
ssize_t pkt_recvfrom(FAR struct socket *psock, FAR void *buf, size_t len,
int flags, FAR struct sockaddr *from,
FAR socklen_t *fromlen)
{
FAR struct pkt_conn_s *conn = (FAR struct pkt_conn_s *)psock->s_conn;
FAR struct net_driver_s *dev;
struct pkt_recvfrom_s state;
ssize_t ret;
/* If a 'from' address has been provided, verify that it is large
* enough to hold this address family.
*/
if (from != NULL && *fromlen < sizeof(sa_family_t))
{
return -EINVAL;
}
if (psock->s_type != -SOCK_RAW)
{
nerr("ERROR: Unsupported socket type: %d\n", psock->s_type);
ret = -ENOSYS;
}
/* Perform the packet recvfrom() operation */
/* Initialize the state structure. This is done with interrupts
* disabled because we don't want anything to happen until we
* are ready.
*/
net_lock();
pkt_recvfrom_initialize(psock, buf, len, from, fromlen, &state);
/* Get the device driver that will service this transfer */
dev = pkt_find_device(conn);
if (dev == NULL)
{
ret = -ENODEV;
goto errout_with_state;
}
/* TODO pkt_recvfrom_initialize() expects from to be of type sockaddr_in, but
* in our case is sockaddr_ll
*/
#if 0
ret = pkt_connect(conn, NULL);
if (ret < 0)
{
goto errout_with_state;
}
#endif
/* Set the socket state to receiving */
psock->s_flags = _SS_SETSTATE(psock->s_flags, _SF_RECV);
/* Set up the callback in the connection */
state.pr_cb = pkt_callback_alloc(dev, conn);
if (state.pr_cb)
{
state.pr_cb->flags = (PKT_NEWDATA | PKT_POLL);
state.pr_cb->priv = (FAR void *)&state;
state.pr_cb->event = pkt_recvfrom_interrupt;
/* Notify the device driver of the receive call */
#if 0 /* Not implemented */
pkt_recvfrom_rxnotify(conn);
#endif
/* Wait for either the receive to complete or for an error/timeout to occur.
* NOTES: (1) net_lockedwait will also terminate if a signal is received, (2)
* interrupts are disabled! They will be re-enabled while the task sleeps
* and automatically re-enabled when the task restarts.
*/
ret = net_lockedwait(&state.pr_sem);
/* Make sure that no further interrupts are processed */
pkt_callback_free(dev, conn, state.pr_cb);
ret = pkt_recvfrom_result(ret, &state);
}
else
{
ret = -EBUSY;
}
/* Set the socket state to idle */
psock->s_flags = _SS_SETSTATE(psock->s_flags, _SF_IDLE);
errout_with_state:
net_unlock();
pkt_recvfrom_uninitialize(&state);
return ret;
}
#endif /* CONFIG_NET */

20
net/pkt/pkt_sockif.c
View file

@ -43,6 +43,7 @@
#include <sys/socket.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/net/net.h>
@ -67,9 +68,10 @@ static ssize_t pkt_sendto(FAR struct socket *psock, FAR const void *buf,
const struct sock_intf_s g_pkt_sockif =
{
pkt_setup, /* si_setup */
pkt_send, /* si_send */
pkt_sendto, /* si_sendto */
pkt_setup, /* si_setup */
pkt_send, /* si_send */
pkt_sendto, /* si_sendto */
pkt_recvfrom /* si_recvfrom */
};
/****************************************************************************
@ -162,9 +164,9 @@ static int pkt_setup(FAR struct socket *psock, int protocol)
* flags Send flags
*
* Returned Value:
* On success, returns the number of characters sent. On error, -1 is
* returned, and errno is set appropriately (see send() for the list of
* appropriate errors values.
* On success, returns the number of characters sent. On error, a negated
* errno value is returned (see send() for the list of appropriate error
* values.
*
****************************************************************************/
@ -208,9 +210,9 @@ static ssize_t pkt_send(FAR struct socket *psock, FAR const void *buf,
* tolen The length of the address structure
*
* Returned Value:
* On success, returns the number of characters sent. On error, -1 is
* returned, and errno is set appropriately (see send_to() for the list of
* appropriate errors values.
* On success, returns the number of characters sent. On error, a negated
* errno value is returned (see send_to() for the list of appropriate error
* values.
*
****************************************************************************/

4
net/socket/Make.defs
View file

@ -44,9 +44,9 @@ SOCK_CSRCS += net_dupsd2.c net_clone.c net_poll.c net_vfcntl.c
SOCK_CSRCS += net_sockif.c
ifeq ($(CONFIG_NET_IPv4),y)
SOCK_CSRCS += inet_sockif.c
SOCK_CSRCS += inet_sockif.c inet_recvfrom.c
else ifeq ($(CONFIG_NET_IPv6),y)
SOCK_CSRCS += inet_sockif.c
SOCK_CSRCS += inet_sockif.c inet_recvfrom.c
endif
# TCP/IP support

1664
net/socket/inet_recvfrom.c Normal file
View file

File diff suppressed because it is too large Load diff

19
net/socket/inet_sockif.c
View file

@ -70,9 +70,10 @@ static ssize_t inet_sendto(FAR struct socket *psock, FAR const void *buf,
const struct sock_intf_s g_inet_sockif =
{
inet_setup, /* si_setup */
inet_send, /* si_send */
inet_sendto, /* si_sendto */
inet_setup, /* si_setup */
inet_send, /* si_send */
inet_sendto, /* si_sendto */
inet_recvfrom /* si_recvfrom */
};
/****************************************************************************
@ -237,9 +238,9 @@ static int inet_setup(FAR struct socket *psock, int protocol)
* flags Send flags
*
* Returned Value:
* On success, returns the number of characters sent. On error, -1 is
* returned, and errno is set appropriately (see send() for the list of
* appropriate errors values.
* On success, returns the number of characters sent. On error, a negated
* errno value is returned (see send() for the list of appropriate error
* values.
*
****************************************************************************/
@ -333,9 +334,9 @@ static ssize_t inet_send(FAR struct socket *psock, FAR const void *buf,
* tolen The length of the address structure
*
* Returned Value:
* On success, returns the number of characters sent. On error, -1 is
* returned, and errno is set appropriately (see send_to() for the list of
* appropriate errors values.
* On success, returns the number of characters sent. On error, a negated
* errno value is returned (see send_to() for the list of appropriate error
* values.
*
****************************************************************************/

1906
net/socket/recvfrom.c
View file

File diff suppressed because it is too large Load diff

37
net/socket/socket.h
View file

@ -431,13 +431,46 @@ int net_timeo(systime_t start_time, socktimeo_t timeo);
* In this case the process will also receive a SIGPIPE unless
* MSG_NOSIGNAL is set.
*
* Assumptions:
*
****************************************************************************/
ssize_t psock_send(FAR struct socket *psock, FAR const void *buf, size_t len,
int flags);
/****************************************************************************
* Name: inet_recvfrom
*
* Description:
* Implements the socket recvfrom interface for the case of the AF_INET
* and AF_INET6 address families. inet_recvfrom() receives messages from
* a socket, and may be used to receive data on a socket whether or not it
* is connection-oriented.
*
* If 'from' is not NULL, and the underlying protocol provides the source
* address, this source address is filled in. The argument 'fromlen' is
* initialized to the size of the buffer associated with from, and
* modified on return to indicate the actual size of the address stored
* there.
*
* Parameters:
* psock A pointer to a NuttX-specific, internal socket structure
* buf Buffer to receive data
* len Length of buffer
* flags Receive flags
* from Address of source (may be NULL)
* fromlen The length of the address structure
*
* Returned Value:
* On success, returns the number of characters received. If no data is
* available to be received and the peer has performed an orderly shutdown,
* recv() will return 0. Otherwise, on errors, a negated errno value is
* returned (see recvfrom() for the list of appropriate error values).
*
****************************************************************************/
ssize_t inet_recvfrom(FAR struct socket *psock, FAR void *buf, size_t len,
int flags, FAR struct sockaddr *from,
FAR socklen_t *fromlen);
#undef EXTERN
#if defined(__cplusplus)
}