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nuttx/net/udp/udp_recvfrom.c

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/****************************************************************************
* net/udp/udp_recvfrom.c
*
* Copyright (C) 2020 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>
#if defined(CONFIG_NET) && defined(CONFIG_NET_UDP)
#include <string.h>
#include <errno.h>
#include <debug.h>
#include <assert.h>
#include <nuttx/semaphore.h>
#include <nuttx/net/net.h>
#include <nuttx/mm/iob.h>
#include <nuttx/net/netdev.h>
#include <nuttx/net/ip.h>
#include <nuttx/net/udp.h>
#include "netdev/netdev.h"
#include "devif/devif.h"
#include "udp/udp.h"
#include "socket/socket.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define IPv4BUF ((struct ipv4_hdr_s *)&dev->d_buf[NET_LL_HDRLEN(dev)])
#define IPv6BUF ((struct ipv6_hdr_s *)&dev->d_buf[NET_LL_HDRLEN(dev)])
#define UDPIPv4BUF ((struct udp_hdr_s *)&dev->d_buf[NET_LL_HDRLEN(dev) + IPv4_HDRLEN])
#define UDPIPv6BUF ((struct udp_hdr_s *)&dev->d_buf[NET_LL_HDRLEN(dev) + IPv6_HDRLEN])
/****************************************************************************
* Private Types
****************************************************************************/
struct udp_recvfrom_s
{
FAR struct socket *ir_sock; /* The parent socket structure */
FAR struct devif_callback_s *ir_cb; /* Reference to callback instance */
sem_t ir_sem; /* Semaphore signals recv completion */
size_t ir_buflen; /* Length of receive buffer */
uint8_t *ir_buffer; /* Pointer to receive buffer */
FAR struct sockaddr *ir_from; /* Address of sender */
FAR socklen_t *ir_fromlen; /* Number of bytes allocated for address of sender */
ssize_t ir_recvlen; /* The received length */
int ir_result; /* Success:OK, failure:negated errno */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: udp_update_recvlen
*
* Description:
* Update information about space available for new data and update size
* of data in buffer, This logic accounts for the case where
* udp_readahead() sets state.ir_recvlen == -1 .
*
* Input Parameters:
* pstate recvfrom state structure
* recvlen size of new data appended to buffer
*
* Returned Value:
* None
*
****************************************************************************/
static inline void udp_update_recvlen(FAR struct udp_recvfrom_s *pstate,
size_t recvlen)
{
if (pstate->ir_recvlen < 0)
{
pstate->ir_recvlen = 0;
}
pstate->ir_recvlen += recvlen;
pstate->ir_buffer += recvlen;
pstate->ir_buflen -= recvlen;
}
/****************************************************************************
* Name: udp_recvfrom_newdata
*
* Description:
* Copy the read data from the packet
*
* Input Parameters:
* dev The structure of the network driver that generated the event.
* pstate recvfrom state structure
*
* Returned Value:
* The number of bytes taken from the packet.
*
* Assumptions:
* The network is locked.
*
****************************************************************************/
static size_t udp_recvfrom_newdata(FAR struct net_driver_s *dev,
FAR struct udp_recvfrom_s *pstate)
{
size_t recvlen;
/* Get the length of the data to return */
if (dev->d_len > pstate->ir_buflen)
{
recvlen = pstate->ir_buflen;
}
else
{
recvlen = dev->d_len;
}
/* Copy the new appdata into the user buffer */
memcpy(pstate->ir_buffer, dev->d_appdata, recvlen);
ninfo("Received %d bytes (of %d)\n", (int)recvlen, (int)dev->d_len);
/* Update the accumulated size of the data read */
udp_update_recvlen(pstate, recvlen);
return recvlen;
}
/****************************************************************************
* Name: udp_newdata
*
* Description:
* Copy the read data from the packet
*
* Input Parameters:
* dev The structure of the network driver that generated the event
* pstate recvfrom state structure
*
* Returned Value:
* None.
*
* Assumptions:
* The network is locked.
*
****************************************************************************/
static inline void udp_newdata(FAR struct net_driver_s *dev,
FAR struct udp_recvfrom_s *pstate)
{
/* Take as much data from the packet as we can */
udp_recvfrom_newdata(dev, pstate);
/* Indicate no data in the buffer */
dev->d_len = 0;
}
static inline void udp_readahead(struct udp_recvfrom_s *pstate)
{
FAR struct udp_conn_s *conn = (FAR struct udp_conn_s *)pstate->ir_sock->s_conn;
FAR struct iob_s *iob;
int recvlen;
/* Check there is any UDP datagram already buffered in a read-ahead
* buffer.
*/
pstate->ir_recvlen = -1;
if ((iob = iob_peek_queue(&conn->readahead)) != NULL)
{
FAR struct iob_s *tmp;
uint8_t src_addr_size;
DEBUGASSERT(iob->io_pktlen > 0);
/* Transfer that buffered data from the I/O buffer chain into
* the user buffer.
*/
recvlen = iob_copyout(&src_addr_size, iob, sizeof(uint8_t), 0);
if (recvlen != sizeof(uint8_t))
{
goto out;
}
if (0
#ifdef CONFIG_NET_IPv6
|| src_addr_size == sizeof(struct sockaddr_in6)
#endif
#ifdef CONFIG_NET_IPv4
|| src_addr_size == sizeof(struct sockaddr_in)
#endif
)
{
if (pstate->ir_from)
{
socklen_t len = *pstate->ir_fromlen;
len = (socklen_t)
src_addr_size > len ? len : (socklen_t)src_addr_size;
recvlen = iob_copyout((FAR uint8_t *)pstate->ir_from, iob,
len, sizeof(uint8_t));
if (recvlen != len)
{
goto out;
}
}
}
if (pstate->ir_buflen > 0)
{
recvlen = iob_copyout(pstate->ir_buffer, iob, pstate->ir_buflen,
src_addr_size + sizeof(uint8_t));
ninfo("Received %d bytes (of %d)\n", recvlen, iob->io_pktlen);
/* Update the accumulated size of the data read */
pstate->ir_recvlen = recvlen;
pstate->ir_buffer += recvlen;
pstate->ir_buflen -= recvlen;
}
else
{
pstate->ir_recvlen = 0;
}
out:
/* Remove the I/O buffer chain from the head of the read-ahead
* buffer queue.
*/
tmp = iob_remove_queue(&conn->readahead);
DEBUGASSERT(tmp == iob);
UNUSED(tmp);
/* And free the I/O buffer chain */
iob_free_chain(iob, IOBUSER_NET_UDP_READAHEAD);
}
}
/****************************************************************************
* Name: udp_sender
*
* Description:
* Getting the sender's address from the UDP packet
*
* Input Parameters:
* dev - The device driver data structure
* pstate - the recvfrom state structure
*
* Returned Value:
* None
*
* Assumptions:
* The network is locked.
*
****************************************************************************/
static inline void udp_sender(FAR struct net_driver_s *dev,
FAR struct udp_recvfrom_s *pstate)
{
/* Get the family from the packet type, IP address from the IP header, and
* the port number from the UDP header.
*/
#ifdef CONFIG_NET_IPv6
#ifdef CONFIG_NET_IPv4
if (IFF_IS_IPv6(dev->d_flags))
#endif
{
FAR struct sockaddr_in6 *infrom =
(FAR struct sockaddr_in6 *)pstate->ir_from;
FAR socklen_t *fromlen = pstate->ir_fromlen;
if (infrom)
{
FAR struct udp_hdr_s *udp = UDPIPv6BUF;
FAR struct ipv6_hdr_s *ipv6 = IPv6BUF;
infrom->sin6_family = AF_INET6;
infrom->sin6_port = udp->srcport;
*fromlen = sizeof(struct sockaddr_in6);
net_ipv6addr_copy(infrom->sin6_addr.s6_addr, ipv6->srcipaddr);
}
}
#endif /* CONFIG_NET_IPv6 */
#ifdef CONFIG_NET_IPv4
#ifdef CONFIG_NET_IPv6
else
#endif
{
FAR struct sockaddr_in *infrom =
(FAR struct sockaddr_in *)pstate->ir_from;
if (infrom)
{
#ifdef CONFIG_NET_IPv6
FAR struct udp_conn_s *conn =
(FAR struct udp_conn_s *)pstate->ir_sock->s_conn;
/* Hybrid dual-stack IPv6/IPv4 implementations recognize a special
* class of addresses, the IPv4-mapped IPv6 addresses.
*/
if (conn->domain == PF_INET6)
{
FAR struct sockaddr_in6 *infrom6 =
(FAR struct sockaddr_in6 *)infrom;
FAR socklen_t *fromlen = pstate->ir_fromlen;
FAR struct udp_hdr_s *udp = UDPIPv6BUF;
FAR struct ipv6_hdr_s *ipv6 = IPv6BUF;
in_addr_t ipv4addr;
/* Encode the IPv4 address as an IPv4-mapped IPv6 address */
infrom6->sin6_family = AF_INET6;
infrom6->sin6_port = udp->srcport;
*fromlen = sizeof(struct sockaddr_in6);
ipv4addr = net_ip4addr_conv32(ipv6->srcipaddr);
ip6_map_ipv4addr(ipv4addr, infrom6->sin6_addr.s6_addr16);
}
else
#endif
{
FAR struct udp_hdr_s *udp = UDPIPv4BUF;
FAR struct ipv4_hdr_s *ipv4 = IPv4BUF;
infrom->sin_family = AF_INET;
infrom->sin_port = udp->srcport;
net_ipv4addr_copy(infrom->sin_addr.s_addr,
net_ip4addr_conv32(ipv4->srcipaddr));
memset(infrom->sin_zero, 0, sizeof(infrom->sin_zero));
}
}
}
#endif /* CONFIG_NET_IPv4 */
}
/****************************************************************************
* Name: udp_terminate
*
* Description:
* Terminate the UDP transfer.
*
* Input Parameters:
* pstate - The recvfrom state structure
* result - The result of the operation
*
* Returned Value:
* None
*
****************************************************************************/
static void udp_terminate(FAR struct udp_recvfrom_s *pstate, int result)
{
/* Don't allow any further UDP call backs. */
pstate->ir_cb->flags = 0;
pstate->ir_cb->priv = NULL;
pstate->ir_cb->event = NULL;
/* Save the result of the transfer */
pstate->ir_result = result;
/* Wake up the waiting thread, returning the number of bytes
* actually read.
*/
nxsem_post(&pstate->ir_sem);
}
/****************************************************************************
* Name: udp_eventhandler
*
* Description:
* This function is called with the network locked to perform the actual
* UDP receive operation via by the lower, device interfacing layer.
*
* Input Parameters:
* dev The structure of the network driver that generated the event.
* pvconn The connection structure associated with the socket
* flags Set of events describing why the callback was invoked
*
* Returned Value:
* None
*
* Assumptions:
* The network is locked.
*
****************************************************************************/
static uint16_t udp_eventhandler(FAR struct net_driver_s *dev,
FAR void *pvconn, FAR void *pvpriv,
uint16_t flags)
{
FAR struct udp_recvfrom_s *pstate = (FAR struct udp_recvfrom_s *)pvpriv;
ninfo("flags: %04x\n", flags);
/* 'priv' might be null in some race conditions (?) */
if (pstate)
{
/* If the network device has gone down, then we will have terminate
* the wait now with an error.
*/
if ((flags & NETDEV_DOWN) != 0)
{
/* Terminate the transfer with an error. */
nerr("ERROR: Network is down\n");
udp_terminate(pstate, -ENETUNREACH);
}
/* If new data is available, then complete the read action. */
else if ((flags & UDP_NEWDATA) != 0)
{
/* Copy the data from the packet */
udp_newdata(dev, pstate);
/* We are finished. */
ninfo("UDP done\n");
/* Save the sender's address in the caller's 'from' location */
udp_sender(dev, pstate);
/* Don't allow any further UDP call backs. */
udp_terminate(pstate, OK);
/* Indicate that the data has been consumed */
flags &= ~UDP_NEWDATA;
}
}
return flags;
}
/****************************************************************************
* Name: udp_recvfrom_initialize
*
* Description:
* Initialize the state structure
*
* Input 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 udp_recvfrom_initialize(FAR struct socket *psock, FAR void *buf,
size_t len, FAR struct sockaddr *infrom,
FAR socklen_t *fromlen,
FAR struct udp_recvfrom_s *pstate)
{
/* Initialize the state structure. */
memset(pstate, 0, sizeof(struct udp_recvfrom_s));
/* This semaphore is used for signaling and, hence, should not have
* priority inheritance enabled.
*/
nxsem_init(&pstate->ir_sem, 0, 0); /* Doesn't really fail */
nxsem_setprotocol(&pstate->ir_sem, SEM_PRIO_NONE);
pstate->ir_buflen = len;
pstate->ir_buffer = buf;
pstate->ir_from = infrom;
pstate->ir_fromlen = fromlen;
/* Set up the start time for the timeout */
pstate->ir_sock = psock;
}
/* The only un-initialization that has to be performed is destroying the
* semaphore.
*/
#define udp_recvfrom_uninitialize(s) nxsem_destroy(&(s)->ir_sem)
/****************************************************************************
* Name: udp_recvfrom_result
*
* Description:
* Evaluate the result of the recv operations
*
* Input Parameters:
* result The result of the net_timedwait 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 udp_recvfrom_result(int result, struct udp_recvfrom_s *pstate)
{
/* Check for a error/timeout detected by the event handler. Errors are
* signaled by negative errno values for the rcv length
*/
if (pstate->ir_result < 0)
{
/* This might return EAGAIN on a timeout or ENOTCONN on loss of
* connection (TCP only)
*/
return pstate->ir_result;
}
/* If net_timedwait failed, then we were probably reawakened by a signal. In
* this case, net_timedwait will have returned negated errno appropriately.
*/
if (result < 0)
{
return result;
}
return pstate->ir_recvlen;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: psock_udp_recvfrom
*
* Description:
* Perform the recvfrom operation for a UDP SOCK_DGRAM
*
* Input Parameters:
* psock Pointer to the socket structure for the SOCK_DRAM socket
* buf Buffer to receive data
* len Length of buffer
* from INET address of source (may be NULL)
*
* Returned Value:
* On success, returns the number of characters received. On error,
* -errno is returned (see recvfrom for list of errnos).
*
* Assumptions:
*
****************************************************************************/
ssize_t psock_udp_recvfrom(FAR struct socket *psock, FAR void *buf,
size_t len, int flags, FAR struct sockaddr *from,
FAR socklen_t *fromlen)
{
FAR struct udp_conn_s *conn = (FAR struct udp_conn_s *)psock->s_conn;
FAR struct net_driver_s *dev;
struct udp_recvfrom_s state;
int ret;
/* Perform the UDP recvfrom() operation */
/* Initialize the state structure. This is done with the network locked
* because we don't want anything to happen until we are ready.
*/
net_lock();
udp_recvfrom_initialize(psock, buf, len, from, fromlen, &state);
/* Copy the read-ahead data from the packet */
udp_readahead(&state);
/* The default return value is the number of bytes that we just copied
* into the user buffer. We will return this if the socket has become
* disconnected or if the user request was completely satisfied with
* data from the readahead buffers.
*/
ret = state.ir_recvlen;
/* Handle non-blocking UDP sockets */
if (_SS_ISNONBLOCK(psock->s_flags) || (flags & MSG_DONTWAIT) != 0)
{
/* Return the number of bytes read from the read-ahead buffer if
* something was received (already in 'ret'); EAGAIN if not.
*/
if (ret < 0)
{
/* Nothing was received */
ret = -EAGAIN;
}
}
/* It is okay to block if we need to. If there is space to receive anything
* more, then we will wait to receive the data. Otherwise return the number
* of bytes read from the read-ahead buffer (already in 'ret').
*
* NOTE: that udp_readahead() may set state.ir_recvlen == -1.
*/
else if (state.ir_recvlen <= 0)
{
/* Get the device that will handle the packet transfers. This may be
* NULL if the UDP socket is bound to INADDR_ANY. In that case, no
* NETDEV_DOWN notifications will be received.
*/
dev = udp_find_laddr_device(conn);
/* Set up the callback in the connection */
state.ir_cb = udp_callback_alloc(dev, conn);
if (state.ir_cb)
{
/* Set up the callback in the connection */
state.ir_cb->flags = (UDP_NEWDATA | NETDEV_DOWN);
state.ir_cb->priv = (FAR void *)&state;
state.ir_cb->event = udp_eventhandler;
/* Wait for either the receive to complete or for an error/timeout
* to occur. net_timedwait will also terminate if a signal is
* received.
*/
ret = net_timedwait(&state. ir_sem, _SO_TIMEOUT(psock->s_rcvtimeo));
if (ret == -ETIMEDOUT)
{
ret = -EAGAIN;
}
/* Make sure that no further events are processed */
udp_callback_free(dev, conn, state.ir_cb);
ret = udp_recvfrom_result(ret, &state);
}
else
{
ret = -EBUSY;
}
}
net_unlock();
udp_recvfrom_uninitialize(&state);
return ret;
}
#endif /* CONFIG_NET && CONFIG_NET_UDP */
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