/**************************************************************************** * net/ipforward/ipfwd_forward.c * * Copyright (C) 2017 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. The name of the author may not be used to endorse or promote * products derived from this software without specific prior * written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 #include #include #include #include #include #include #include #include #include #include "devif/devif.h" #include "netdev/netdev.h" #include "arp/arp.h" #include "neighbor/neighbor.h" #include "ipforward/ipforward.h" #ifdef CONFIG_NET_IPFORWARD /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: forward_ipselect * * Description: * If both IPv4 and IPv6 support are enabled, then we will need to select * which one to use when generating the outgoing packet. If only one * domain is selected, then the setup is already in place and we need do * nothing. * * Input Parameters: * fwd - The forwarding state structure * * Returned Value: * None * * Assumptions: * The network is locked. * ****************************************************************************/ #if defined(CONFIG_NET_IPv4) && defined(CONFIG_NET_IPv6) static inline void forward_ipselect(FAR struct forward_s *fwd) { FAR struct net_driver_s *dev = fwd->f_dev; /* Select IPv4 or IPv6 */ if (fwd->f_domain == PF_INET) { /* Clear a bit in the d_flags to distinguish this from an IPv6 packet */ IFF_SET_IPv4(dev->d_flags); /* Set the offset to the beginning of the UDP data payload */ dev->d_appdata = &dev->d_buf[IPv4UDP_HDRLEN + NET_LL_HDRLEN(dev)]; } else { /* Set a bit in the d_flags to distinguish this from an IPv6 packet */ IFF_SET_IPv6(dev->d_flags); /* Set the offset to the beginning of the UDP data payload */ dev->d_appdata = &dev->d_buf[IPv6_HDRLEN + NET_LL_HDRLEN(dev)]; } } #endif /**************************************************************************** * Name: ipfwd_addrchk * * Description: * Check if the destination IP address is in the IPv4 ARP or IPv6 Neighbor * tables. If not, then the send won't actually make it out... it will be * replaced with an ARP request (IPv4) or a Neighbor Solicitation (IPv6). * * NOTE 1: This could be an expensive check if there are a lot of * entries in the ARP or Neighbor tables. * * NOTE 2: If we are actually harvesting IP addresses on incoming IP * packets, then this check should not be necessary; the MAC mapping * should already be in the ARP table in many cases (IPv4 only). * * NOTE 3: If CONFIG_NET_ARP_SEND then we can be assured that the IP * address mapping is already in the ARP table. * * Input Parameters: * fwd - The forwarding state structure * * Returned Value: * true - The Ethernet MAC address is in the ARP or Neighbor table (OR * the network device is not Ethernet). * * Assumptions: * The network is locked. * ****************************************************************************/ #ifdef CONFIG_NET_ETHERNET static inline bool ipfwd_addrchk(FAR struct forward_s *fwd) { DEBUGASSERT(fwd != NULL && fwd->f_iob != NULL && fwd->f_dev != NULL); /* REVISIT: Could the MAC address not also be in a routing table? */ if (fwd->f_dev->d_lltype != NET_LL_ETHERNET) { return true; } #ifdef CONFIG_NET_IPv4 #ifdef CONFIG_NET_IPv6 if (fwd->f_domain == PF_INET) #endif { #if !defined(CONFIG_NET_ARP_IPIN) && !defined(CONFIG_NET_ARP_SEND) FAR struct ipv4_hdr_s *ipv4 = (FAR struct ipv4_hdr_s *)fwd->f_iob->io_data; return (arp_find(*(in_addr_t *)ipv4->destipaddr) != NULL); #else return true; #endif } #endif /* CONFIG_NET_IPv4 */ #ifdef CONFIG_NET_IPv6 #ifdef CONFIG_NET_IPv4 else #endif { #if defined(CONFIG_NET_ICMPv6_NEIGHBOR) FAR struct ipv6_hdr_s *ipv6 = (FAR struct ipv6_hdr_s *)fwd->f_iob->io_data; return (neighbor_findentry(ipv6->destipaddr) != NULL); #else return true; #endif } #endif /* CONFIG_NET_IPv6 */ } #else /* CONFIG_NET_ETHERNET */ # define ipfwd_addrchk(r) (true) #endif /* CONFIG_NET_ETHERNET */ /**************************************************************************** * Name: ipfwd_eventhandler * * Description: * This function is called with the network locked to perform the actual * send operation when polled by the lower, device interfacing layer. * * Input Parameters: * dev The structure of the network driver that generated the * event * conn An instance of the forwarding structure cast to (void *) * pvpriv An instance of struct forward_s cast to (void *) * flags Set of events describing why the callback was invoked * * Returned Value: * Modified value of the input flags * * Assumptions: * The network is locked * ****************************************************************************/ static uint16_t ipfwd_eventhandler(FAR struct net_driver_s *dev, FAR void *conn, FAR void *pvpriv, uint16_t flags) { FAR struct forward_s *fwd = (FAR struct forward_s *)pvpriv; ninfo("flags: %04x\n", flags); DEBUGASSERT(fwd != NULL && fwd->f_iob != NULL && fwd->f_dev != NULL); /* Make sure that this is from the forwarding device */ if (dev == fwd->f_dev) { /* If the network device has gone down, then we will have terminate * the wait now with an error. */ if ((flags & NETDEV_DOWN) != 0) { /* Terminate the transfer with an error. */ nwarn("WARNING: Network is down... Dropping\n"); ipfwd_dropstats(fwd); } /* Check if the outgoing packet is available. It may have been claimed * by a sendto event handler serving a different thread -OR- if the * output buffer currently contains unprocessed incoming data. In * these cases we will just have to wait for the next polling cycle. */ else if (dev->d_sndlen > 0 || (flags & IPFWD_NEWDATA) != 0) { /* Another thread has beat us sending data or the buffer is busy, * Wait for the next polling cycle and check again. */ return flags; } /* It looks like we are good to forward the data */ else { #if defined(CONFIG_NET_IPv4) && defined(CONFIG_NET_IPv6) /* If both IPv4 and IPv6 support are enabled, then we will need to * select which one to use when generating the outgoing packet. * If only one domain is selected, then the setup is already in * place and we need do nothing. */ forward_ipselect(fwd); #endif /* Copy the user data into d_appdata and send it. */ devif_forward(fwd); flags &= ~DEVPOLL_MASK; /* Check if the destination IP address is in the ARP or Neighbor * table. If not, then the send won't actually make it out... it * will be replaced with an ARP request or Neighbor Solicitation. */ if (!ipfwd_addrchk(fwd)) { return flags; } } /* Free the allocated callback structure */ fwd->f_cb->flags = 0; fwd->f_cb->priv = NULL; fwd->f_cb->event = NULL; ipfwd_callback_free(dev, fwd->f_cb); /* Free any IOBs */ if (fwd->f_iob != NULL) { iob_free_chain(fwd->f_iob); } /* And release the forwarding state structure */ ipfwd_free(fwd); } return flags; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: ipfwd_forward * * Description: * Called by the IP forwarding logic when a packet is received on one * network device, but must be forwarded on another network device. * * Set up to forward the packet on the specified device. This function * will set up a send event handler that will perform the actual send * asynchronously and must return without waiting for the send to * complete. * * Input Parameters: * fwd - An initialized instance of the common forwarding structure that * includes everything needed to perform the forwarding operation. * * Returned Value: * Zero is returned if the packet was successfully forwarded; A negated * errno value is returned if the packet is not forwardable. In that * latter case, the caller should free the IOB list and drop the packet. * ****************************************************************************/ int ipfwd_forward(FAR struct forward_s *fwd) { DEBUGASSERT(fwd != NULL && fwd->f_iob != NULL && fwd->f_dev != NULL); /* Set up the callback in the connection */ fwd->f_cb = ipfwd_callback_alloc(fwd->f_dev); if (fwd->f_cb != NULL) { fwd->f_cb->flags = (IPFWD_POLL | NETDEV_DOWN); fwd->f_cb->priv = (FAR void *)fwd; fwd->f_cb->event = ipfwd_eventhandler; /* Notify the device driver of the availability of TX data */ netdev_txnotify_dev(fwd->f_dev); return OK; } return -EBUSY; } #endif /* CONFIG_NET_IPFORWARD */