/****************************************************************************
* net/tcp/tcp_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>
#ifdef CONFIG_NET_TCP
#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/tcp.h>
#include "netdev/netdev.h"
#include "devif/devif.h"
#include "tcp/tcp.h"
#include "socket/socket.h"
/****************************************************************************
* Private Types
****************************************************************************/
struct tcp_recvfrom_s
{
FAR struct tcp_conn_s *ir_conn; /* Connection associated with the socket */
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: tcp_update_recvlen
*
* Description:
* Update information about space available for new data and update size
* of data in buffer.
*
* Input Parameters:
* pstate recvfrom state structure
* recvlen size of new data appended to buffer
*
* Returned Value:
* None
*
****************************************************************************/
static inline void tcp_update_recvlen(FAR struct tcp_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: tcp_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 tcp_recvfrom_newdata(FAR struct net_driver_s *dev,
FAR struct tcp_recvfrom_s *pstate)
{
unsigned int offset;
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 */
offset = (dev->d_appdata - dev->d_iob->io_data) - dev->d_iob->io_offset;
recvlen = iob_copyout(pstate->ir_buffer, dev->d_iob, recvlen, offset);
/* Trim the copied buffers */
dev->d_iob = iob_trimhead(dev->d_iob, recvlen + offset);
ninfo("Received %d bytes (of %d)\n", (int)recvlen, (int)dev->d_len);
/* Update the accumulated size of the data read */
tcp_update_recvlen(pstate, recvlen);
return recvlen;
}
/****************************************************************************
* Name: tcp_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 uint16_t tcp_newdata(FAR struct net_driver_s *dev,
FAR struct tcp_recvfrom_s *pstate,
uint16_t flags)
{
FAR struct tcp_conn_s *conn = pstate->ir_conn;
/* Take as much data from the packet as we can */
size_t recvlen = tcp_recvfrom_newdata(dev, pstate);
/* If there is more data left in the packet that we could not buffer, then
* add it to the read-ahead buffers.
*/
if (recvlen < dev->d_len)
{
uint16_t nsaved;
uint16_t buflen = dev->d_len - recvlen;
nsaved = tcp_datahandler(dev, conn, 0);
if (nsaved < buflen)
{
nwarn("WARNING: packet data not fully saved "
"(%d/%u/%zu/%u bytes)\n",
buflen - nsaved,
(unsigned int)nsaved,
recvlen,
(unsigned int)dev->d_len);
}
recvlen += nsaved;
}
else
{
netdev_iob_release(dev);
}
if (recvlen < dev->d_len)
{
/* Clear the TCP_CLOSE because we effectively dropped the FIN as well.
*/
flags &= ~TCP_CLOSE;
}
net_incr32(conn->rcvseq, recvlen);
/* Indicate no data in the buffer */
dev->d_len = 0;
return flags;
}
/****************************************************************************
* Name: tcp_readahead
*
* Description:
* Copy the read-ahead data from the packet
*
* Input Parameters:
* pstate recvfrom state structure
*
* Returned Value:
* None
*
* Assumptions:
* The network is locked.
*
****************************************************************************/
static inline void tcp_readahead(struct tcp_recvfrom_s *pstate)
{
FAR struct tcp_conn_s *conn = pstate->ir_conn;
FAR struct iob_s *iob;
int recvlen;
/* Check there is any TCP data already buffered in a read-ahead
* buffer.
*/
while ((iob = conn->readahead) != NULL &&
pstate->ir_buflen > 0)
{
DEBUGASSERT(iob->io_pktlen > 0);
/* Transfer that buffered data from the I/O buffer chain into
* the user buffer.
*/
recvlen = iob_copyout(pstate->ir_buffer, iob, pstate->ir_buflen, 0);
ninfo("Received %d bytes (of %d)\n", recvlen, iob->io_pktlen);
/* Update the accumulated size of the data read */
tcp_update_recvlen(pstate, recvlen);
/* If we took all of the data from the I/O buffer chain is empty, then
* release it. If there is still data available in the I/O buffer
* chain, then just trim the data that we have taken from the
* beginning of the I/O buffer chain.
*/
if (recvlen >= iob->io_pktlen)
{
/* Free free the I/O buffer chain */
iob_free_chain(iob);
conn->readahead = NULL;
}
else
{
/* The bytes that we have received from the head of the I/O
* buffer chain.
*/
conn->readahead = iob_trimhead(iob, recvlen);
}
}
}
/****************************************************************************
* Name: tcp_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 tcp_sender(FAR struct net_driver_s *dev,
FAR struct tcp_recvfrom_s *pstate)
{
/* Get the family from the packet type, IP address from the IP header, and
* the port number from the TCP 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;
if (infrom)
{
FAR struct tcp_hdr_s *tcp = TCPIPv6BUF;
FAR struct ipv6_hdr_s *ipv6 = IPv6BUF;
infrom->sin6_family = AF_INET6;
infrom->sin6_port = tcp->srcport;
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)
{
FAR struct tcp_hdr_s *tcp = TCPIPv4BUF;
FAR struct ipv4_hdr_s *ipv4 = IPv4BUF;
infrom->sin_family = AF_INET;
infrom->sin_port = tcp->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: tcp_recvhandler
*
* Description:
* This function is called with the network locked to perform the actual
* TCP 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 tcp_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 tcp_recvhandler(FAR struct net_driver_s *dev,
FAR void *pvpriv, uint16_t flags)
{
FAR struct tcp_recvfrom_s *pstate = pvpriv;
ninfo("flags: %04x\n", flags);
/* 'priv' might be null in some race conditions (?) */
if (pstate)
{
/* If new data is available, then complete the read action. */
if ((flags & TCP_NEWDATA) != 0)
{
/* Save the sender's address in the caller's 'from' location */
tcp_sender(dev, pstate);
/* Copy the data from the packet (saving any unused bytes from the
* packet in the read-ahead buffer).
*/
flags = tcp_newdata(dev, pstate, flags);
/* Indicate that the data has been consumed and that an ACK
* should be sent.
*/
flags = (flags & ~TCP_NEWDATA) | TCP_SNDACK;
/* Check for transfer complete. We will consider the
* TCP/IP transfer complete as soon as any data has been received.
* This is safe because if any additional data is received, it
* will be retained in the TCP/IP read-ahead buffer until the
* next receive is performed.
*/
if ((pstate->ir_recvlen > 0 &&
(pstate->ir_cb->flags & TCP_WAITALL) == 0) ||
pstate->ir_buflen == 0)
{
ninfo("TCP resume\n");
/* The TCP receive buffer is non-empty. Return now and don't
* allow any further TCP call backs.
*/
pstate->ir_cb->flags = 0;
pstate->ir_cb->priv = NULL;
pstate->ir_cb->event = NULL;
/* Wake up the waiting thread, returning the number of bytes
* actually read.
*/
nxsem_post(&pstate->ir_sem);
}
}
/* Check for a loss of connection.
*
* TCP_DISCONN_EVENTS:
* TCP_CLOSE: The remote host has closed the connection
* TCP_ABORT: The remote host has aborted the connection
* TCP_TIMEDOUT: Connection aborted due to too many retransmissions.
* NETDEV_DOWN: The network device went down
*/
else if ((flags & TCP_DISCONN_EVENTS) != 0)
{
FAR struct tcp_conn_s *conn = pstate->ir_conn;
nwarn("WARNING: Lost connection\n");
/* We could get here recursively through the callback actions of
* tcp_lost_connection(). So don't repeat that action if we have
* already been disconnected.
*/
DEBUGASSERT(conn != NULL);
if (_SS_ISCONNECTED(conn->sconn.s_flags))
{
/* Handle loss-of-connection event */
tcp_lost_connection(conn, pstate->ir_cb, flags);
}
/* Check if the peer gracefully closed the connection. */
if ((flags & TCP_CLOSE) != 0)
{
/* This case should always return success (zero)! The value of
* ir_recvlen, if zero, will indicate that the connection was
* gracefully closed.
*/
pstate->ir_result = 0;
}
else
{
pstate->ir_result = -ENOTCONN;
}
/* Wake up the waiting thread */
nxsem_post(&pstate->ir_sem);
}
}
return flags;
}
/****************************************************************************
* Name: tcp_recvfrom_initialize
*
* Description:
* Initialize the state structure
*
* Input Parameters:
* conn The TCP connection of interest
* 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 tcp_recvfrom_initialize(FAR struct tcp_conn_s *conn,
FAR void *buf, size_t len,
FAR struct sockaddr *infrom,
FAR socklen_t *fromlen,
FAR struct tcp_recvfrom_s *pstate)
{
/* Initialize the state structure. */
memset(pstate, 0, sizeof(struct tcp_recvfrom_s));
nxsem_init(&pstate->ir_sem, 0, 0); /* Doesn't really fail */
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_conn = conn;
}
/* The only un-initialization that has to be performed is destroying the
* semaphore.
*/
#define tcp_recvfrom_uninitialize(s) nxsem_destroy(&(s)->ir_sem)
/****************************************************************************
* Name: tcp_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 tcp_recvfrom_result(int result, struct tcp_recvfrom_s *pstate)
{
/* Check if any data were received. If so, then return their length and
* ignore any error codes.
*/
if (pstate->ir_recvlen > 0)
{
return pstate->ir_recvlen;
}
/* If no data were received, return the error code instead. The event
* handler error is prioritized over any previous error.
*/
return (pstate->ir_result < 0) ? pstate->ir_result : result;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: psock_tcp_recvfrom
*
* Description:
* Perform the recvfrom operation for a TCP/IP SOCK_STREAM
*
* Input Parameters:
* psock Pointer to the socket structure for the SOCK_DRAM socket
* msg Receive info and buffer for receive data
* flags Receive flags
*
* 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_tcp_recvfrom(FAR struct socket *psock, FAR struct msghdr *msg,
int flags)
{
FAR struct sockaddr *from = msg->msg_name;
FAR socklen_t *fromlen = &msg->msg_namelen;
FAR void *buf = msg->msg_iov->iov_base;
size_t len = msg->msg_iov->iov_len;
struct tcp_recvfrom_s state;
FAR struct tcp_conn_s *conn;
int ret;
net_lock();
conn = psock->s_conn;
/* Initialize the state structure. This is done with the network locked
* because we don't want anything to happen until we are ready.
*/
tcp_recvfrom_initialize(conn, buf, len, from, fromlen, &state);
/* Handle any any TCP data already buffered in a read-ahead buffer. NOTE
* that there may be read-ahead data to be retrieved even after the
* socket has been disconnected.
*/
tcp_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;
/* Verify that the SOCK_STREAM has been and still is connected */
if (!_SS_ISCONNECTED(conn->sconn.s_flags))
{
/* Was any data transferred from the readahead buffer after we were
* disconnected? If so, then return the number of bytes received. We
* will wait to return end disconnection indications the next time that
* recvfrom() is called.
*
* If no data was received (i.e., ret == 0 -- it will not be
* negative) and the connection was gracefully closed by the remote
* peer, then return success. If ir_recvlen is zero, the caller of
* recvfrom() will get an end-of-file indication.
*/
if (ret <= 0 && !_SS_ISCLOSED(conn->sconn.s_flags))
{
/* Nothing was previously received from the read-ahead buffers.
* The SOCK_STREAM must be (re-)connected in order to receive any
* additional data.
*/
ret = -ENOTCONN;
}
}
/* In general, this implementation will not support non-blocking socket
* operations... except in a few cases: Here for TCP receive with read-
* ahead enabled. If this socket is configured as non-blocking then
* return EAGAIN if no data was obtained from the read-ahead buffers.
*/
else 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').
*/
else
/* We get here when we we decide that we need to setup the wait for
* incoming TCP/IP data. Just a few more conditions to check:
*
* 1) Make sure that there is buffer space to receive additional data
* (state.ir_buflen > 0). This could be zero, for example, we filled
* the user buffer with data from the read-ahead buffers. And
* 2) then we not want to wait if we already obtained some data from the
* read-ahead buffer. In that case, return now with what we have (don't
* want for more because there may be no timeout).
* 3) If however MSG_WAITALL flag is set, block here till all requested
* data are received (or there is a timeout / error).
*/
if (((flags & MSG_WAITALL) != 0 || state.ir_recvlen == 0) &&
state.ir_buflen > 0)
{
/* Set up the callback in the connection */
state.ir_cb = tcp_callback_alloc(conn);
if (state.ir_cb)
{
state.ir_cb->flags = (TCP_NEWDATA | TCP_DISCONN_EVENTS);
state.ir_cb->flags |= (flags & MSG_WAITALL) ? TCP_WAITALL : 0;
state.ir_cb->priv = (FAR void *)&state;
state.ir_cb->event = tcp_recvhandler;
/* 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 */
tcp_callback_free(conn, state.ir_cb);
ret = tcp_recvfrom_result(ret, &state);
}
else if (ret <= 0)
{
ret = -EBUSY;
}
}
/* Receive additional data from read-ahead buffer, send the ACK timely.
*
* Revisit: Because IOBs are system-wide resources, consuming the read
* ahead buffer would update recv window of all connections in the system,
* not only this particular connection.
*/
if (tcp_should_send_recvwindow(conn))
{
netdev_txnotify_dev(conn->dev);
}
net_unlock();
tcp_recvfrom_uninitialize(&state);
return (ssize_t)ret;
}
#endif /* CONFIG_NET_TCP */