/**************************************************************************** * net/socket/accept.c * * Copyright (C) 2007-2012, 2015-2016 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 #if defined(CONFIG_NET) && CONFIG_NSOCKET_DESCRIPTORS > 0 && \ (defined(CONFIG_NET_TCP) || defined(CONFIG_NET_LOCAL_STREAM)) #include #include #include #include #include #include #include #include "tcp/tcp.h" #include "local/local.h" #include "socket/socket.h" /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Function: psock_accept * * Description: * The psock_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 psock_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, psock_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, psock_accept returns * EAGAIN. * * Parameters: * psock Reference to the listening socket structure * addr Receives the address of the connecting client * addrlen Input: allocated size of 'addr', Return: returned size of 'addr' * newsock Location to return the accepted socket information. * * Returned Value: * Returns 0 (OK) on success. On failure, it returns -1 (ERROR) with the * errno variable set to indicate the nature of the error. * * EAGAIN or EWOULDBLOCK * The socket is marked non-blocking and no connections are present to * be accepted. * 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. * ****************************************************************************/ int psock_accept(FAR struct socket *psock, FAR struct sockaddr *addr, FAR socklen_t *addrlen, FAR struct socket *newsock) { int errcode; int ret; DEBUGASSERT(psock != NULL); /* Treat as a cancellation point */ (void)enter_cancellation_point(); /* Is the socket a stream? */ if (psock->s_type != SOCK_STREAM) { errcode = EOPNOTSUPP; goto errout; } /* Is the socket listening for a connection? */ if (!_SS_ISLISTENING(psock->s_flags)) { errcode = EINVAL; goto errout; } /* Verify that a valid memory block has been provided to receive the * address */ if (addr) { /* If an address is provided, then the length must also be provided. */ DEBUGASSERT(addrlen); /* A valid length depends on the address domain */ switch (psock->s_domain) { #ifdef CONFIG_NET_IPv4 case PF_INET: { if (*addrlen < sizeof(struct sockaddr_in)) { errcode = EBADF; goto errout; } } break; #endif /* CONFIG_NET_IPv4 */ #ifdef CONFIG_NET_IPv6 case PF_INET6: { if (*addrlen < sizeof(struct sockaddr_in6)) { errcode = EBADF; goto errout; } } break; #endif /* CONFIG_NET_IPv6 */ #ifdef CONFIG_NET_LOCAL_STREAM case PF_LOCAL: { if (*addrlen < sizeof(sa_family_t)) { errcode = EBADF; goto errout; } } break; #endif /* CONFIG_NET_IPv6 */ default: DEBUGPANIC(); errcode = EINVAL; goto errout; } } /* Initialize the socket structure. */ newsock->s_domain = psock->s_domain; newsock->s_type = SOCK_STREAM; /* Perform the correct accept operation for this address domain */ #ifdef CONFIG_NET_LOCAL_STREAM #ifdef CONFIG_NET_TCP if (psock->s_domain == PF_LOCAL) #endif { /* Perform the local accept operation (with the network unlocked) */ ret = psock_local_accept(psock, addr, addrlen, &newsock->s_conn); if (ret < 0) { errcode = -ret; goto errout; } } #endif /* CONFIG_NET_LOCAL_STREAM */ #ifdef CONFIG_NET_TCP #ifdef CONFIG_NET_LOCAL_STREAM else #endif { /* Perform the local accept operation (with the network locked) */ net_lock(); ret = psock_tcp_accept(psock, addr, addrlen, &newsock->s_conn); if (ret < 0) { net_unlock(); errcode = -ret; goto errout; } /* Begin monitoring for TCP connection events on the newly connected * socket */ ret = net_startmonitor(newsock); if (ret < 0) { /* net_startmonitor() can only fail on certain race conditions * where the connection was lost just before this function was * called. Undo everything we have done and return a failure. */ net_unlock(); errcode = -ret; goto errout_after_accept; } net_unlock(); } #endif /* CONFIG_NET_TCP */ /* Mark the new socket as connected. */ newsock->s_flags |= _SF_CONNECTED; newsock->s_flags &= ~_SF_CLOSED; leave_cancellation_point(); return OK; errout_after_accept: psock_close(newsock); errout: set_errno(errcode); leave_cancellation_point(); return ERROR; } /**************************************************************************** * 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 descriptor * 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. * ****************************************************************************/ int accept(int sockfd, FAR struct sockaddr *addr, FAR socklen_t *addrlen) { FAR struct socket *psock = sockfd_socket(sockfd); FAR struct socket *newsock; int newfd; int errcode; int ret; /* accept() is a cancellation point */ (void)enter_cancellation_point(); /* Verify that the sockfd corresponds to valid, allocated socket */ if (psock == NULL || 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) { errcode = ENOTSOCK; } else #endif { errcode = EBADF; } goto errout; } /* Allocate a socket descriptor for the new connection now (so that it * cannot fail later) */ newfd = sockfd_allocate(0); if (newfd < 0) { errcode = ENFILE; goto errout; } newsock = sockfd_socket(newfd); if (newsock == NULL) { errcode = ENFILE; goto errout_with_socket; } ret = psock_accept(psock, addr, addrlen, newsock); if (ret < 0) { /* The errno value has already been set */ sockfd_release(newfd); leave_cancellation_point(); return ERROR; } leave_cancellation_point(); return newfd; errout_with_socket: sockfd_release(newfd); errout: set_errno(errcode); leave_cancellation_point(); return ERROR; } #endif /* CONFIG_NET && CONFIG_NSOCKET_DESCRIPTORS && (CONFIG_NET_TCP || CONFIG_NET_LOCAL_STREAM) */