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incubator-nuttx/net/udp/udp_recvfrom.c

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/****************************************************************************
* net/udp/udp_recvfrom.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* 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 <netinet/in.h>
#include "netdev/netdev.h"
#include "devif/devif.h"
#include "udp/udp.h"
#include "socket/socket.h"
#include "utils/utils.h"
/****************************************************************************
* Private Types
****************************************************************************/
struct udp_recvfrom_s
{
FAR struct udp_conn_s *ir_conn; /* Connection associated with the socket */
FAR struct devif_callback_s *ir_cb; /* Reference to callback instance */
FAR struct msghdr *ir_msg; /* Receive info and buffer */
sem_t ir_sem; /* Semaphore signals recv completion */
ssize_t ir_recvlen; /* The received length */
int ir_result; /* Success:OK, failure:negated errno */
int ir_flags; /* Flags on received message. */
};
/****************************************************************************
* Private Functions
****************************************************************************/
#ifdef CONFIG_NET_SOCKOPTS
static void udp_recvpktinfo(FAR struct udp_recvfrom_s *pstate,
FAR void *srcaddr, uint8_t ifindex)
{
FAR struct msghdr *msg = pstate->ir_msg;
FAR struct udp_conn_s *conn = pstate->ir_conn;
#ifdef CONFIG_NET_IPv4
if (conn->domain == PF_INET &&
_SO_GETOPT(conn->sconn.s_options, IP_PKTINFO))
{
FAR struct sockaddr_in *infrom = srcaddr;
struct in_pktinfo pktinfo;
pktinfo.ipi_ifindex = ifindex;
pktinfo.ipi_addr.s_addr = infrom->sin_addr.s_addr;
pktinfo.ipi_spec_dst.s_addr = conn->u.ipv4.laddr;
cmsg_append(msg, IPPROTO_IP, IP_PKTINFO, &pktinfo, sizeof(pktinfo));
}
#endif
#ifdef CONFIG_NET_IPv6
if (conn->domain == PF_INET6 &&
_SO_GETOPT(conn->sconn.s_options, IPV6_RECVPKTINFO))
{
FAR struct sockaddr_in6 *infrom = srcaddr;
struct in6_pktinfo pktinfo;
pktinfo.ipi6_ifindex = ifindex;
net_ipv6addr_copy(&pktinfo.ipi6_addr, infrom->sin6_addr.s6_addr);
cmsg_append(msg, IPPROTO_IPV6, IPV6_PKTINFO, &pktinfo,
sizeof(pktinfo));
}
#endif
}
#else
#define udp_recvpktinfo(p, s, i) {(void)(p); (void)(s); (void)(i);}
#endif
/****************************************************************************
* 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:
* None.
*
* Assumptions:
* The network is locked.
*
****************************************************************************/
static inline 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_msg->msg_iov->iov_len)
{
recvlen = pstate->ir_msg->msg_iov->iov_len;
}
else
{
recvlen = dev->d_len;
}
/* Copy the new appdata into the user buffer */
recvlen = iob_copyout(pstate->ir_msg->msg_iov->iov_base, dev->d_iob,
recvlen, dev->d_appdata - dev->d_iob->io_data -
dev->d_iob->io_offset);
/* Update the size of the data read */
pstate->ir_recvlen = recvlen;
dev->d_len = 0;
return recvlen;
}
static inline void udp_readahead(struct udp_recvfrom_s *pstate)
{
FAR struct udp_conn_s *conn = pstate->ir_conn;
FAR struct iob_s *iob;
/* Check there is any UDP datagram already buffered in a read-ahead
* buffer.
*/
pstate->ir_recvlen = -1;
if ((iob = conn->readahead) != NULL)
{
int recvlen;
int offset = 0;
uint16_t datalen;
uint8_t src_addr_size;
uint8_t ifindex;
#ifdef CONFIG_NET_IPv6
uint8_t srcaddr[sizeof(struct sockaddr_in6)];
#else
uint8_t srcaddr[sizeof(struct sockaddr_in)];
#endif
/* Unflatten saved connection information
* Layout: |datalen|ifindex|src_addr_size|src_addr|data|
*/
recvlen = iob_copyout((FAR uint8_t *)&datalen, iob,
sizeof(datalen), offset);
offset += sizeof(datalen);
DEBUGASSERT(recvlen == sizeof(datalen));
#ifdef CONFIG_NETDEV_IFINDEX
recvlen = iob_copyout(&ifindex, iob, sizeof(ifindex), offset);
offset += sizeof(ifindex);
DEBUGASSERT(recvlen == sizeof(ifindex));
#else
ifindex = 1;
#endif
recvlen = iob_copyout(&src_addr_size, iob,
sizeof(src_addr_size), offset);
offset += sizeof(src_addr_size);
DEBUGASSERT(recvlen == sizeof(src_addr_size));
recvlen = iob_copyout(srcaddr, iob, src_addr_size, offset);
offset += src_addr_size;
DEBUGASSERT(recvlen == src_addr_size);
/* Copy to user */
recvlen = iob_copyout(pstate->ir_msg->msg_iov->iov_base, iob,
MIN(pstate->ir_msg->msg_iov->iov_len, datalen),
offset);
/* Update the accumulated size of the data read */
pstate->ir_recvlen = recvlen;
ninfo("Received %d bytes (of %d, total %d)\n",
recvlen, datalen, iob->io_pktlen);
if (pstate->ir_msg->msg_name)
{
pstate->ir_msg->msg_namelen =
src_addr_size > pstate->ir_msg->msg_namelen ?
pstate->ir_msg->msg_namelen : src_addr_size;
memcpy(pstate->ir_msg->msg_name, srcaddr,
pstate->ir_msg->msg_namelen);
}
udp_recvpktinfo(pstate, srcaddr, ifindex);
/* Remove the packet from the head of the I/O buffer chain. */
if (!(pstate->ir_flags & MSG_PEEK))
{
if (offset + datalen >= iob->io_pktlen)
{
iob_free_chain(iob);
conn->readahead = NULL;
}
else
{
conn->readahead = iob_trimhead(iob, offset + datalen);
}
}
}
}
/****************************************************************************
* 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)
{
#ifdef CONFIG_NET_IPv6
uint8_t srcaddr[sizeof(struct sockaddr_in6)];
#else
uint8_t srcaddr[sizeof(struct sockaddr_in)];
#endif
socklen_t fromlen = 0;
/* 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 *)srcaddr;
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
{
#ifdef CONFIG_NET_IPv6
FAR struct udp_conn_s *conn = pstate->ir_conn;
if (conn->domain == PF_INET6)
{
/* Hybrid dual-stack IPv6/IPv4 implementations recognize a special
* class of addresses, the IPv4-mapped IPv6 addresses.
*/
FAR struct sockaddr_in6 *infrom6 =
(FAR struct sockaddr_in6 *)srcaddr;
FAR struct udp_hdr_s *udp = UDPIPv4BUF;
FAR struct ipv4_hdr_s *ipv4 = IPv4BUF;
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(ipv4->srcipaddr);
ip6_map_ipv4addr(ipv4addr, infrom6->sin6_addr.s6_addr16);
}
else
#endif
{
FAR struct sockaddr_in *infrom = (FAR struct sockaddr_in *)srcaddr;
FAR struct udp_hdr_s *udp = UDPIPv4BUF;
FAR struct ipv4_hdr_s *ipv4 = IPv4BUF;
infrom->sin_family = AF_INET;
infrom->sin_port = udp->srcport;
fromlen = sizeof(struct sockaddr_in);
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 */
if (pstate->ir_msg->msg_name)
{
pstate->ir_msg->msg_namelen = fromlen > pstate->ir_msg->msg_namelen ?
pstate->ir_msg->msg_namelen : fromlen;
memcpy(pstate->ir_msg->msg_name, srcaddr, pstate->ir_msg->msg_namelen);
}
#ifdef CONFIG_NETDEV_IFINDEX
udp_recvpktinfo(pstate, srcaddr, dev->d_ifindex);
#else
udp_recvpktinfo(pstate, srcaddr, 1);
#endif
}
/****************************************************************************
* 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.
* pvpriv An instance of struct udp_recvfrom_s cast to void*
* 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 *pvpriv, uint16_t flags)
{
FAR struct udp_recvfrom_s *pstate = 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)
{
/* Save the sender's address in the caller's 'from' location */
udp_sender(dev, pstate);
/* Copy the data from the packet */
udp_recvfrom_newdata(dev, pstate);
/* We are finished. */
ninfo("UDP done\n");
/* Don't allow any further UDP call backs. */
udp_terminate(pstate, OK);
/* In read-ahead mode, UDP_NEWDATA and iob need to be reserved
* and let udp_callback to call net_dataevent and put this packet
* into conn->readahead
*/
if (!(pstate->ir_flags & MSG_PEEK))
{
/* Indicate that the data has been consumed */
flags &= ~UDP_NEWDATA;
/* Indicate no data in the buffer */
netdev_iob_release(dev);
}
}
}
return flags;
}
/****************************************************************************
* Name: udp_recvfrom_initialize
*
* Description:
* Initialize the state structure
*
* Input Parameters:
* conn The UDP connection of interest
* msg Receive info and buffer for receive data
* pstate A pointer to the state structure to be initialized
*
* Returned Value:
* None
*
* Assumptions:
*
****************************************************************************/
static void udp_recvfrom_initialize(FAR struct udp_conn_s *conn,
FAR struct msghdr *msg,
FAR struct udp_recvfrom_s *pstate,
int flags)
{
/* Initialize the state structure. */
memset(pstate, 0, sizeof(struct udp_recvfrom_s));
nxsem_init(&pstate->ir_sem, 0, 0); /* Doesn't really fail */
pstate->ir_msg = msg;
pstate->ir_flags = flags;
/* Set up the start time for the timeout */
pstate->ir_conn = conn;
}
/* 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_sem_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_sem_timedwait failed, then we were probably reawakened by a
* signal. In this case, net_sem_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
* msg Receive info and buffer for receive data
*
* 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 struct msghdr *msg,
int flags)
{
FAR struct udp_conn_s *conn = 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(conn, msg, &state, flags);
/* 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(conn->sconn.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_sem_timedwait will also terminate if a signal is
* received.
*/
ret = net_sem_timedwait(&state.ir_sem,
_SO_TIMEOUT(conn->sconn.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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