/**************************************************************************** * net/icmp/icmp_input.c * Handling incoming ICMP input * * Copyright (C) 2007-2009, 2012, 2014-2015, 2017, 2019 Gregory Nutt. All * rights reserved. * Author: Gregory Nutt * * Adapted for NuttX from logic in uIP which also has a BSD-like license: * * Original author Adam Dunkels * Copyright () 2001-2003, Adam Dunkels. * All rights reserved. * * 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 #ifdef CONFIG_NET #include #include #include #include #include #include #include #include #include #include #include "devif/devif.h" #include "icmp/icmp.h" #include "utils/utils.h" #ifdef CONFIG_NET_ICMP /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #ifdef CONFIG_NET_ICMP_SOCKET /**************************************************************************** * Private Types ****************************************************************************/ struct icmp_deliver_s { FAR struct net_driver_s *dev; /* Current network device */ uint16_t iphdrlen; /* The size of the IPv4 header */ bool delivered; /* Whether the message is delivered */ }; /**************************************************************************** * Private Functions ****************************************************************************/ static bool icmp_filter(uint32_t filter, uint8_t type) { if (type < 32) { return ((1u << type) & filter) != 0; } /* Do not block unknown ICMP types */ return 0; } /**************************************************************************** * Name: icmp_datahandler * * Description: * Handle ICMP echo replies that are not accepted by the application. * * Input Parameters: * dev - Device instance only the input packet in d_buf, length = d_len; * conn - A pointer to the ICMP connection structure * iphdrlen - The size of the IPv4 header * * Returned Value: * The number of bytes actually buffered is returned. This will be either * zero or equal to buflen; partial packets are not buffered. * ****************************************************************************/ static uint16_t icmp_datahandler(FAR struct net_driver_s *dev, FAR struct icmp_conn_s *conn, uint16_t iphdrlen) { FAR struct ipv4_hdr_s *ipv4; struct sockaddr_in inaddr; FAR struct iob_s *iob; uint16_t buflen; int ret; iob = iob_tryalloc(false); if (iob == NULL) { return -ENOMEM; } /* Put the IPv4 address at the beginning of the read-ahead buffer */ ipv4 = IPv4BUF; inaddr.sin_family = AF_INET; inaddr.sin_port = 0; net_ipv4addr_copy(inaddr.sin_addr.s_addr, net_ip4addr_conv32(ipv4->srcipaddr)); memset(inaddr.sin_zero, 0, sizeof(inaddr.sin_zero)); /* Copy the src address info into the front of I/O buffer chain which * overwrites the contents of the packet header field. */ memcpy(iob->io_data, &inaddr, sizeof(struct sockaddr_in)); iob_reserve(iob, sizeof(struct sockaddr_in)); /* Copy the ICMP message into the I/O buffer chain (without waiting) */ ret = iob_clone_partial(dev->d_iob, dev->d_iob->io_pktlen, 0, iob, 0, true, false); if (ret < 0) { iob_free_chain(iob); return ret; } buflen = dev->d_len; /* Add the new I/O buffer chain to the tail of the read-ahead queue (again * without waiting). */ ret = iob_tryadd_queue(iob, &conn->readahead); if (ret < 0) { nerr("ERROR: Failed to queue the I/O buffer chain: %d\n", ret); iob_free_chain(iob); } else { ninfo("Buffered %d bytes\n", buflen); } return buflen; } /**************************************************************************** * Name: icmp_delivery_callback * * Description: * Copy the icmp package to the application according to the filter * conditions, but ICMP_ECHO_REPLY is a special message type, if there * is an application waiting, it will also copy. * * Input Parameters: * conn - A pointer to the ICMP connection structure. * arg - The context information * ****************************************************************************/ static int icmp_delivery_callback(FAR struct icmp_conn_s *conn, FAR void *arg) { FAR struct icmp_deliver_s *info = arg; FAR struct net_driver_s *dev = info->dev; FAR struct icmp_hdr_s *icmp = IPBUF(info->iphdrlen); if (icmp_filter(conn->filter, icmp->type) && (icmp->type != ICMP_ECHO_REPLY || conn->id != icmp->id || conn->dev != dev)) { return 0; } info->delivered = true; if (devif_conn_event(dev, ICMP_NEWDATA, conn->sconn.list) == ICMP_NEWDATA) { icmp_datahandler(dev, conn, info->iphdrlen); } return 0; } /**************************************************************************** * Name: icmp_deliver * * Description: * Copy the icmp package to the application according to the filter * conditions, but ICMP_ECHO_REPLY is a special message type, if there * is an application waiting, it will also copy. * * Input Parameters: * dev - Reference to a device driver structure. * iphdrlen - The size of the IP header. This may be larger than * IPv4_HDRLEN if IP option are present. * ****************************************************************************/ static bool icmp_deliver(FAR struct net_driver_s *dev, uint16_t iphdrlen) { struct icmp_deliver_s info; info.dev = dev; info.iphdrlen = iphdrlen; info.delivered = false; icmp_foreach(icmp_delivery_callback, &info); return info.delivered; } #endif /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: icmp_input * * Description: * Handle incoming ICMP input * * Input Parameters: * dev - The device driver structure containing the received ICMP * packet * * Returned Value: * None * * Assumptions: * The network is locked. * ****************************************************************************/ void icmp_input(FAR struct net_driver_s *dev) { FAR struct ipv4_hdr_s *ipv4 = IPv4BUF; FAR struct icmp_hdr_s *icmp; /* Get the IP header length (accounting for possible options). */ uint16_t iphdrlen = (ipv4->vhl & IPv4_HLMASK) << 2; #ifdef CONFIG_NET_ICMP_SOCKET bool delivered = icmp_deliver(dev, iphdrlen); #endif #ifdef CONFIG_NET_STATISTICS g_netstats.icmp.recv++; #endif /* The ICMP header immediately follows the IP header */ icmp = IPBUF(iphdrlen); /* ICMP echo (i.e., ping) processing. This is simple, we only change the * ICMP type from ECHO to ECHO_REPLY and adjust the ICMP checksum before * we return the packet. */ if (icmp->type == ICMP_ECHO_REQUEST) { /* Change the ICMP type */ icmp->type = ICMP_ECHO_REPLY; /* Swap IP addresses. */ net_ipv4addr_hdrcopy(ipv4->destipaddr, ipv4->srcipaddr); net_ipv4addr_hdrcopy(ipv4->srcipaddr, &dev->d_ipaddr); /* Recalculate the ICMP checksum */ #if 0 /* Get the IP header length (accounting for possible options). */ iphdrlen = (ipv4->vhl & IPv4_HLMASK) << 2; /* The slow way... sum over the ICMP message */ icmp->icmpchksum = 0; icmp->icmpchksum = ~icmp_chksum(dev, (((uint16_t)ipv4->len[0] << 8) | (uint16_t)ipv4->len[1]) - iphdrlen); if (icmp->icmpchksum == 0) { icmp->icmpchksum = 0xffff; } #else /* The quick way -- Since only the type has changed, just adjust the * checksum for the change of type */ if (icmp->icmpchksum >= HTONS(0xffff - (ICMP_ECHO_REQUEST << 8))) { icmp->icmpchksum += HTONS(ICMP_ECHO_REQUEST << 8) + 1; } else { icmp->icmpchksum += HTONS(ICMP_ECHO_REQUEST << 8); } #endif ninfo("Outgoing ICMP packet length: %d (%d)\n", dev->d_len, (ipv4->len[0] << 8) | ipv4->len[1]); #ifdef CONFIG_NET_STATISTICS g_netstats.icmp.sent++; g_netstats.ipv4.sent++; #endif } #if CONFIG_NET_ICMP_PMTU_ENTRIES > 0 else if (icmp->type == ICMP_DEST_UNREACHABLE) { if (icmp->icode == ICMP_FRAG_NEEDED) { FAR struct icmp_pmtu_entry *entry; FAR struct ipv4_hdr_s *inner; int mtu; mtu = ntohs(icmp->data[0]) << 16 | ntohs(icmp->data[1]); if (mtu <= 0) { goto typeerr; } inner = (FAR struct ipv4_hdr_s *)(icmp + 1); entry = icmpv4_find_pmtu_entry( net_ip4addr_conv32(inner->destipaddr)); if (entry == NULL) { icmpv4_add_pmtu_entry( net_ip4addr_conv32(inner->destipaddr), mtu); } else { entry->pmtu = mtu; } goto icmp_send_nothing; } } #endif /* Otherwise the ICMP input was not processed */ else { #ifdef CONFIG_NET_ICMP_SOCKET if (delivered) { goto icmp_send_nothing; } else if (icmp->type == ICMP_ECHO_REQUEST) { goto drop; } #endif nwarn("WARNING: Unknown ICMP cmd: %d\n", icmp->type); goto typeerr; } return; typeerr: #ifdef CONFIG_NET_STATISTICS g_netstats.icmp.typeerr++; #endif #ifdef CONFIG_NET_ICMP_SOCKET drop: #ifdef CONFIG_NET_STATISTICS g_netstats.icmp.drop++; #endif #endif #if defined(CONFIG_NET_ICMP_SOCKET) || CONFIG_NET_ICMP_PMTU_ENTRIES > 0 icmp_send_nothing: #endif dev->d_len = 0; } #endif /* CONFIG_NET_ICMP */ #endif /* CONFIG_NET */