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nuttx/net/socket/accept.c

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/****************************************************************************
* net/socket/accept.c
*
* Copyright (C) 2007-2012, 2015 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) && CONFIG_NSOCKET_DESCRIPTORS > 0 && defined(CONFIG_NET_TCP)
#include <sys/types.h>
#include <sys/socket.h>
#include <semaphore.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <arch/irq.h>
#include <nuttx/net/net.h>
#include <nuttx/net/ip.h>
#include "tcp/tcp.h"
#include "socket/socket.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
struct accept_s
{
FAR struct socket *acpt_sock; /* The accepting socket */
sem_t acpt_sem; /* Wait for interrupt event */
FAR struct sockaddr *acpt_addr; /* Return connection address */
FAR struct tcp_conn_s *acpt_newconn; /* The accepted connection */
int acpt_result; /* The result of the wait */
};
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Function: accept_tcpsender
*
* Description:
* Get the sender's address from the UDP packet
*
* Parameters:
* psock - The state structure of the accepting socket
* conn - The newly accepted TCP connection
* pstate - the recvfrom state structure
*
* Returned Value:
* None
*
* Assumptions:
* Running at the interrupt level
*
****************************************************************************/
#ifdef CONFIG_NET_TCP
static inline void accept_tcpsender(FAR struct socket *psock,
FAR struct tcp_conn_s *conn,
FAR struct sockaddr *addr)
{
if (addr)
{
#ifdef CONFIG_NET_IPv4
#ifdef CONFIG_NET_IPv6
/* If both IPv4 and IPv6 support are enabled, then we will need to
* select which one to use when obtaining the sender's IP address.
*/
if (psock->s_domain == PF_INET)
#endif /* CONFIG_NET_IPv6 */
{
FAR struct sockaddr_in *inaddr = (FAR struct sockaddr_in *)addr;
inaddr->sin_family = AF_INET;
inaddr->sin_port = conn->rport;
net_ipv4addr_copy(inaddr->sin_addr.s_addr, conn->u.ipv4.raddr);
}
#endif /* CONFIG_NET_IPv4 */
#ifdef CONFIG_NET_IPv6
#ifdef CONFIG_NET_IPv4
/* Otherwise, this the IPv6 address is needed */
else
#endif /* CONFIG_NET_IPv4 */
{
FAR struct sockaddr_in6 *inaddr = (FAR struct sockaddr_in6 *)addr;
DEBUGASSERT(psock->s_domain == PF_INET6);
inaddr->sin6_family = AF_INET6;
inaddr->sin6_port = conn->rport;
net_ipv6addr_copy(inaddr->sin6_addr.s6_addr, conn->u.ipv6.raddr);
}
#endif /* CONFIG_NET_IPv6 */
}
}
#endif /* CONFIG_NET_TCP */
/****************************************************************************
* Function: accept_interrupt
*
* Description:
* Receive interrupt level callbacks when connections occur
*
* Parameters:
* listener The conection stucture of the listener
* conn The connection stucture that was just accepted
*
* Returned Value:
* None
*
* Assumptions:
* Running at the interrupt level
*
****************************************************************************/
static int accept_interrupt(FAR struct tcp_conn_s *listener,
FAR struct tcp_conn_s *conn)
{
struct accept_s *pstate = (struct accept_s *)listener->accept_private;
int ret = -EINVAL;
if (pstate)
{
/* Get the connection address */
accept_tcpsender(pstate->acpt_sock, conn, pstate->acpt_addr);
/* Save the connection structure */
pstate->acpt_newconn = conn;
pstate->acpt_result = OK;
/* There should be a reference of one on the new connection */
DEBUGASSERT(conn->crefs == 1);
/* Wake-up the waiting caller thread */
sem_post(&pstate->acpt_sem);
/* Stop any further callbacks */
listener->accept_private = NULL;
listener->accept = NULL;
ret = OK;
}
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Function: accept
*
* Description:
* The accept function is used with connection-based socket types
* (SOCK_STREAM, SOCK_SEQPACKET and SOCK_RDM). It extracts the first
* connection request on the queue of pending connections, creates a new
* connected socket with mostly the same properties as 'sockfd', and
* allocates a new socket descriptor for the socket, which is returned. The
* newly created socket is no longer in the listening state. The original
* socket 'sockfd' is unaffected by this call. Per file descriptor flags
* are not inherited across an accept.
*
* The 'sockfd' argument is a socket descriptor that has been created with
* socket(), bound to a local address with bind(), and is listening for
* connections after a call to listen().
*
* On return, the 'addr' structure is filled in with the address of the
* connecting entity. The 'addrlen' argument initially contains the size
* of the structure pointed to by 'addr'; on return it will contain the
* actual length of the address returned.
*
* If no pending connections are present on the queue, and the socket is
* not marked as non-blocking, accept blocks the caller until a connection
* is present. If the socket is marked non-blocking and no pending
* connections are present on the queue, accept returns EAGAIN.
*
* Parameters:
* sockfd The listening socket descriptior
* addr Receives the address of the connecting client
* addrlen Input: allocated size of 'addr', Return: returned size of 'addr'
*
* Returned Value:
* Returns -1 on error. If it succeeds, it returns a non-negative integer
* that is a descriptor for the accepted socket.
*
* EAGAIN or EWOULDBLOCK
* The socket is marked non-blocking and no connections are present to
* be accepted.
* EBADF
* The descriptor is invalid.
* ENOTSOCK
* The descriptor references a file, not a socket.
* EOPNOTSUPP
* The referenced socket is not of type SOCK_STREAM.
* EINTR
* The system call was interrupted by a signal that was caught before
* a valid connection arrived.
* ECONNABORTED
* A connection has been aborted.
* EINVAL
* Socket is not listening for connections.
* EMFILE
* The per-process limit of open file descriptors has been reached.
* ENFILE
* The system maximum for file descriptors has been reached.
* EFAULT
* The addr parameter is not in a writable part of the user address
* space.
* ENOBUFS or ENOMEM
* Not enough free memory.
* EPROTO
* Protocol error.
* EPERM
* Firewall rules forbid connection.
*
* Assumptions:
*
****************************************************************************/
int accept(int sockfd, FAR struct sockaddr *addr, FAR socklen_t *addrlen)
{
FAR struct socket *psock = sockfd_socket(sockfd);
FAR struct socket *pnewsock;
FAR struct tcp_conn_s *conn;
struct accept_s state;
net_lock_t save;
int newfd;
int err;
int ret;
/* Verify that the sockfd corresponds to valid, allocated socket */
if (!psock || psock->s_crefs <= 0)
{
/* It is not a valid socket description. Distinguish between the cases
* where sockfd is a just valid and when it is a valid file descriptor used
* in the wrong context.
*/
#if CONFIG_NFILE_DESCRIPTORS > 0
if ((unsigned int)sockfd < CONFIG_NFILE_DESCRIPTORS)
{
err = ENOTSOCK;
}
else
#endif
{
err = EBADF;
}
goto errout;
}
/* We have a socket descriptor, but it is a stream? */
if (psock->s_type != SOCK_STREAM)
{
err = EOPNOTSUPP;
goto errout;
}
/* Is the socket listening for a connection? */
if (!_SS_ISLISTENING(psock->s_flags))
{
err = EINVAL;
goto errout;
}
/* Verify that a valid memory block has been provided to receive the
* address
*/
if (addr)
{
switch (psock->s_domain)
{
#ifdef CONFIG_NET_IPv4
case PF_INET:
{
if (*addrlen < sizeof(struct sockaddr_in))
{
err = EBADF;
goto errout;
}
}
break;
#endif /* CONFIG_NET_IPv4 */
#ifdef CONFIG_NET_IPv6
case PF_INET6:
{
if (*addrlen < sizeof(struct sockaddr_in6))
{
err = EBADF;
goto errout;
}
}
break;
#endif /* CONFIG_NET_IPv6 */
default:
DEBUGPANIC();
err = EINVAL;
goto errout;
}
}
/* Allocate a socket descriptor for the new connection now (so that it
* cannot fail later)
*/
newfd = sockfd_allocate(0);
if (newfd < 0)
{
err = ENFILE;
goto errout;
}
pnewsock = sockfd_socket(newfd);
if (!pnewsock)
{
err = ENFILE;
goto errout_with_socket;
}
/* Check the backlog to see if there is a connection already pending for
* this listener.
*/
save = net_lock();
conn = (struct tcp_conn_s *)psock->s_conn;
#ifdef CONFIG_NET_TCPBACKLOG
state.acpt_newconn = tcp_backlogremove(conn);
if (state.acpt_newconn)
{
/* Yes... get the address of the connected client */
nvdbg("Pending conn=%p\n", state.acpt_newconn);
accept_tcpsender(psock, state.acpt_newconn, addr);
}
/* In general, this uIP-based implementation will not support non-blocking
* socket operations... except in a few cases: Here for TCP accept with backlog
* enabled. If this socket is configured as non-blocking then return EAGAIN
* if there is no pending connection in the backlog.
*/
else if (_SS_ISNONBLOCK(psock->s_flags))
{
err = EAGAIN;
goto errout_with_lock;
}
else
#endif
{
/* Set the socket state to accepting */
psock->s_flags = _SS_SETSTATE(psock->s_flags, _SF_ACCEPT);
/* Perform the TCP accept operation */
/* Initialize the state structure. This is done with interrupts
* disabled because we don't want anything to happen until we
* are ready.
*/
state.acpt_sock = psock;
state.acpt_addr = addr;
state.acpt_newconn = NULL;
state.acpt_result = OK;
sem_init(&state.acpt_sem, 0, 0);
/* Set up the callback in the connection */
conn->accept_private = (void*)&state;
conn->accept = accept_interrupt;
/* Wait for the send to complete or an error to occur: NOTES: (1)
* net_lockedwait will also terminate if a signal is received, (2)
* interrupts may be disabled! They will be re-enabled while the
* task sleeps and automatically re-enabled when the task restarts.
*/
ret = net_lockedwait(&state.acpt_sem);
if (ret < 0)
{
/* The value returned by net_lockedwait() the same as the value
* returned by sem_wait(): Zero (OK) is returned on success; -1
* (ERROR) is returned on a failure with the errno value set
* appropriately.
*
* We have to preserve the errno value here because it may be
* altered by intervening operations.
*/
err = get_errno();
}
/* Make sure that no further interrupts are processed */
conn->accept_private = NULL;
conn->accept = NULL;
sem_destroy(&state. acpt_sem);
/* Set the socket state to idle */
psock->s_flags = _SS_SETSTATE(psock->s_flags, _SF_IDLE);
/* Check for a errors. Errors are signalled by negative errno values
* for the send length.
*/
if (state.acpt_result != 0)
{
err = state.acpt_result;
goto errout_with_lock;
}
/* If net_lockedwait failed, then we were probably reawakened by a
* signal. In this case, logic above will have set 'err' to the
* ernno value returned by net_lockedwait().
*/
if (ret < 0)
{
goto errout_with_lock;
}
}
/* Initialize the socket structure and mark the socket as connected.
* (The reference count on the new connection structure was set in the
* interrupt handler).
*/
pnewsock->s_domain = psock->s_domain;
pnewsock->s_type = SOCK_STREAM;
pnewsock->s_conn = state.acpt_newconn;
pnewsock->s_flags |= _SF_CONNECTED;
pnewsock->s_flags &= ~_SF_CLOSED;
/* Begin monitoring for TCP connection events on the newly connected socket */
net_startmonitor(pnewsock);
net_unlock(save);
return newfd;
errout_with_lock:
net_unlock(save);
errout_with_socket:
sockfd_release(newfd);
errout:
set_errno(err);
return ERROR;
}
#endif /* CONFIG_NET && CONFIG_NSOCKET_DESCRIPTORS && CONFIG_NET_TCP */
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