/**************************************************************************** * net/tcp/tcp_backlog.c * * Copyright (C) 2008-2009, 2011-2013 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) && defined(CONFIG_NET_TCP) && defined(CONFIG_NET_TCPBACKLOG) #include #include #include #include #include #include #include #include "devif/devif.h" #include "tcp/tcp.h" /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: tcp_backlogcreate * * Description: * Called from the listen() logic to setup the backlog as specified in the * the listen arguments. * * Assumptions: * Called from normal task logic. The network may or may not be locked. * ****************************************************************************/ int tcp_backlogcreate(FAR struct tcp_conn_s *conn, int nblg) { FAR struct tcp_backlog_s *bls = NULL; FAR struct tcp_blcontainer_s *blc; int size; int offset; int i; ninfo("conn=%p nblg=%d\n", conn, nblg); #ifdef CONFIG_DEBUG_FEATURES if (!conn) { return -EINVAL; } #endif /* Then allocate the backlog as requested */ if (nblg > 0) { /* nblog value must less than SOMAXCONN */ if (nblg > SOMAXCONN) { nblg = SOMAXCONN; } /* Align the list of backlog structures to 32-bit boundaries. This * may be excessive on 24-16-bit address machines; and insufficient * on 64-bit address machines -- REVISIT */ offset = (sizeof(struct tcp_backlog_s) + 3) & ~3; /* Then determine the full size of the allocation include the * tcp_backlog_s, a pre-allocated array of struct tcp_blcontainer_s * and alignment padding */ size = offset + nblg * sizeof(struct tcp_blcontainer_s); /* Then allocate that much */ bls = (FAR struct tcp_backlog_s *)kmm_zalloc(size); if (!bls) { nerr("ERROR: Failed to allocate backlog\n"); return -ENOMEM; } /* Then add all of the pre-allocated containers to the free list */ blc = (FAR struct tcp_blcontainer_s *)(((FAR uint8_t *)bls) + offset); for (i = 0; i < nblg; i++) { sq_addfirst(&blc->bc_node, &bls->bl_free); blc++; } } /* Destroy any existing backlog (shouldn't be any) */ net_lock(); tcp_backlogdestroy(conn); /* Now install the backlog tear-off in the connection. NOTE that bls may * actually be NULL if nblg is <= 0; In that case, we are disabling backlog * support. Since the network is locked, destroying the old backlog and * replace it with the new is an atomic operation */ conn->backlog = bls; net_unlock(); return OK; } /**************************************************************************** * Name: tcp_backlogdestroy * * Description: * (1) Called from tcp_free() whenever a connection is freed. * (2) Called from tcp_backlogcreate() to destroy any old backlog * * NOTE: This function may re-enter tcp_free when a connection that * is freed that has pending connections. * * Assumptions: * Called from network socket logic with the network locked * ****************************************************************************/ int tcp_backlogdestroy(FAR struct tcp_conn_s *conn) { FAR struct tcp_backlog_s *blg; FAR struct tcp_blcontainer_s *blc; FAR struct tcp_conn_s *blconn; ninfo("conn=%p\n", conn); #ifdef CONFIG_DEBUG_FEATURES if (!conn) { return -EINVAL; } #endif /* Make sure that the connection has a backlog to be destroyed */ if (conn->backlog) { /* Remove the backlog structure reference from the connection */ blg = conn->backlog; conn->backlog = NULL; /* Handle any pending connections in the backlog */ while ((blc = (FAR struct tcp_blcontainer_s *)sq_remfirst(&blg->bl_pending)) != NULL) { blconn = blc->bc_conn; if (blconn) { /* REVISIT -- such connections really need to be gracefully closed */ blconn->blparent = NULL; blconn->backlog = NULL; blconn->crefs = 0; tcp_free(blconn); } } /* Then free the entire backlog structure */ kmm_free(blg); } return OK; } /**************************************************************************** * Name: tcp_backlogadd * * Description: * Called tcp_listen when a new connection is made with a listener socket * but when there is no accept() in place to receive the connection. This * function adds the new connection to the backlog. * * Assumptions: * Called from network socket logic with the network locked * ****************************************************************************/ int tcp_backlogadd(FAR struct tcp_conn_s *conn, FAR struct tcp_conn_s *blconn) { FAR struct tcp_backlog_s *bls; FAR struct tcp_blcontainer_s *blc; int ret = -EINVAL; ninfo("conn=%p blconn=%p\n", conn, blconn); #ifdef CONFIG_DEBUG_FEATURES if (!conn) { return -EINVAL; } #endif bls = conn->backlog; if (bls && blconn) { /* Allocate a container for the connection from the free list */ blc = (FAR struct tcp_blcontainer_s *)sq_remfirst(&bls->bl_free); if (!blc) { nerr("ERROR: Failed to allocate container\n"); ret = -ENOMEM; } else { /* Save the connection reference in the container and put the * container at the end of the pending connection list (FIFO). */ blc->bc_conn = blconn; sq_addlast(&blc->bc_node, &bls->bl_pending); ret = OK; } } return ret; } /**************************************************************************** * Name: tcp_backlogremove * * Description: * Called from poll(). Before waiting for a new connection, poll will * call this API to see if there are pending connections in the backlog. * * Assumptions: * Called from network socket logic with the network locked * ****************************************************************************/ #ifndef CONFIG_DISABLE_POLL bool tcp_backlogavailable(FAR struct tcp_conn_s *conn) { return (conn && conn->backlog && !sq_empty(&conn->backlog->bl_pending)); } #endif /**************************************************************************** * Name: tcp_backlogremove * * Description: * Called from accept(). Before waiting for a new connection, accept will * call this API to see if there are pending connections in the backlog. * * Assumptions: * Called from network socket logic with the network locked * ****************************************************************************/ FAR struct tcp_conn_s *tcp_backlogremove(FAR struct tcp_conn_s *conn) { FAR struct tcp_backlog_s *bls; FAR struct tcp_blcontainer_s *blc; FAR struct tcp_conn_s *blconn = NULL; #ifdef CONFIG_DEBUG_FEATURES if (!conn) { return NULL; } #endif bls = conn->backlog; if (bls) { /* Remove the a container at the head of the pending connection list * (FIFO) */ blc = (FAR struct tcp_blcontainer_s *)sq_remfirst(&bls->bl_pending); if (blc) { /* Extract the connection reference from the container and put * container in the free list */ blconn = blc->bc_conn; blc->bc_conn = NULL; sq_addlast(&blc->bc_node, &bls->bl_free); } } ninfo("conn=%p, returning %p\n", conn, blconn); return blconn; } /**************************************************************************** * Name: tcp_backlogdelete * * Description: * Called from tcp_free() when a connection is freed that this also * retained in the pending connection list of a listener. We simply need * to remove the defunct connection from the list. * * Assumptions: * Called from network socket logic with the network locked * ****************************************************************************/ int tcp_backlogdelete(FAR struct tcp_conn_s *conn, FAR struct tcp_conn_s *blconn) { FAR struct tcp_backlog_s *bls; FAR struct tcp_blcontainer_s *blc; FAR struct tcp_blcontainer_s *prev; ninfo("conn=%p blconn=%p\n", conn, blconn); #ifdef CONFIG_DEBUG_FEATURES if (!conn) { return -EINVAL; } #endif bls = conn->backlog; if (bls) { /* Find the container hold the connection */ for (blc = (FAR struct tcp_blcontainer_s *)sq_peek(&bls->bl_pending), prev = NULL; blc; prev = blc, blc = (FAR struct tcp_blcontainer_s *)sq_next(&blc->bc_node)) { if (blc->bc_conn == blconn) { if (prev) { /* Remove the a container from the middle of the list of * pending connections */ (void)sq_remafter(&prev->bc_node, &bls->bl_pending); } else { /* Remove the a container from the head of the list of * pending connections */ (void)sq_remfirst(&bls->bl_pending); } /* Put container in the free list */ blc->bc_conn = NULL; sq_addlast(&blc->bc_node, &bls->bl_free); return OK; } } nerr("ERROR: Failed to find pending connection\n"); return -EINVAL; } return OK; } #endif /* CONFIG_NET && CONFIG_NET_TCP && CONFIG_NET_TCPBACKLOG */