/**************************************************************************** * net/arp/arp_notify.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 #include #include #include #include #include #include #include "arp/arp.h" #ifdef CONFIG_NET_ARP_SEND /**************************************************************************** * Private Data ****************************************************************************/ /* List of tasks waiting for ARP events */ static FAR struct arp_notify_s *g_arp_waiters; /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: arp_wait_setup * * Description: * Called BEFORE an ARP request is sent. This function sets up the ARP * response timeout before the ARP request is sent so that there is * no race condition when arp_wait() is called. * * Assumptions: * This function is called from ARP send and executes in the normal * tasking environment. * ****************************************************************************/ void arp_wait_setup(in_addr_t ipaddr, FAR struct arp_notify_s *notify) { irqstate_t flags; /* Initialize the wait structure */ notify->nt_ipaddr = ipaddr; notify->nt_result = -ETIMEDOUT; nxsem_init(¬ify->nt_sem, 0, 0); /* Add the wait structure to the list with interrupts disabled */ flags = enter_critical_section(); notify->nt_flink = g_arp_waiters; g_arp_waiters = notify; leave_critical_section(flags); } /**************************************************************************** * Name: arp_wait_cancel * * Description: * Cancel any wait set after arp_wait_setup is called but before arp_wait() * is called (arp_wait() will automatically cancel the wait). * * Assumptions: * This function may execute with interrupts disabled when called from * arp_wait(). * ****************************************************************************/ int arp_wait_cancel(FAR struct arp_notify_s *notify) { FAR struct arp_notify_s *curr; FAR struct arp_notify_s *prev; irqstate_t flags; int ret = -ENOENT; /* Remove our wait structure from the list (we may no longer be at the * head of the list). */ flags = enter_critical_section(); for (prev = NULL, curr = g_arp_waiters; curr && curr != notify; prev = curr, curr = curr->nt_flink) { } DEBUGASSERT(curr && curr == notify); if (curr) { if (prev) { prev->nt_flink = notify->nt_flink; } else { g_arp_waiters = notify->nt_flink; } ret = OK; } leave_critical_section(flags); nxsem_destroy(¬ify->nt_sem); return ret; } /**************************************************************************** * Name: arp_wait * * Description: * Called each time that a ARP request is sent. This function will sleep * until either: (1) the matching ARP response is received, or (2) a * timeout occurs. * * Assumptions: * This function is called from ARP send must execute with the network * locked. * ****************************************************************************/ int arp_wait(FAR struct arp_notify_s *notify, unsigned int timeout) { int ret; /* And wait for the ARP response (or a timeout). */ net_timedwait_uninterruptible(¬ify->nt_sem, timeout); /* Then get the real result of the transfer */ ret = notify->nt_result; /* Remove our wait structure from the list (we may no longer be at the * head of the list). */ arp_wait_cancel(notify); return ret; } /**************************************************************************** * Name: arp_notify * * Description: * Called each time that a ARP response is received in order to wake-up * any threads that may be waiting for this particular ARP response. * * Assumptions: * This function is called from the MAC device driver indirectly through * arp_arpin() will execute with the network locked. * ****************************************************************************/ void arp_notify(in_addr_t ipaddr) { FAR struct arp_notify_s *curr; irqstate_t flags; flags = enter_critical_section(); /* Find an entry with the matching IP address in the list of waiters */ for (curr = g_arp_waiters; curr; curr = curr->nt_flink) { /* Does this entry match? If the result is okay, then we have * already notified this waiter and it has not yet taken the * entry from the list. */ if (curr->nt_result != OK && curr->nt_ipaddr == ipaddr) { /* Yes.. Signal the waiting, returning success */ curr->nt_result = OK; nxsem_post(&curr->nt_sem); break; } } leave_critical_section(flags); } #endif /* CONFIG_NET_ARP_SEND */