/**************************************************************************** * net/devif/ipv6_input.c * Device driver IPv6 packet receipt interface * * Copyright (C) 2015, 2017 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Adapted for NuttX from logic in uIP which also has a BSD-like license: * * uIP is an implementation of the TCP/IP protocol stack intended for * small 8-bit and 16-bit microcontrollers. * * uIP provides the necessary protocols for Internet communication, * with a very small code footprint and RAM requirements - the uIP * code size is on the order of a few kilobytes and RAM usage is on * the order of a few hundred bytes. * * 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. * ****************************************************************************/ /**************************************************************************** * uIP is a small implementation of the IP, UDP and TCP protocols (as * well as some basic ICMP stuff). The implementation couples the IP, * UDP, TCP and the application layers very tightly. To keep the size * of the compiled code down, this code frequently uses the goto * statement. While it would be possible to break the ipv6_input() * function into many smaller functions, this would increase the code * size because of the overhead of parameter passing and the fact that * the optimizer would not be as efficient. * * The principle is that we have a small buffer, called the d_buf, * in which the device driver puts an incoming packet. The TCP/IP * stack parses the headers in the packet, and calls the * application. If the remote host has sent data to the application, * this data is present in the d_buf and the application read the * data from there. It is up to the application to put this data into * a byte stream if needed. The application will not be fed with data * that is out of sequence. * * If the application wishes to send data to the peer, it should put * its data into the d_buf. The d_appdata pointer points to the * first available byte. The TCP/IP stack will calculate the * checksums, and fill in the necessary header fields and finally send * the packet back to the peer. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #ifdef CONFIG_NET_IPv6 #include #include #include #include #include #include #include #include #include #include #include #include "neighbor/neighbor.h" #include "tcp/tcp.h" #include "udp/udp.h" #include "sixlowpan/sixlowpan.h" #include "pkt/pkt.h" #include "icmpv6/icmpv6.h" #include "netdev/netdev.h" #include "ipforward/ipforward.h" #include "inet/inet.h" #include "devif/devif.h" /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ /* Macros */ #define IPv6BUF ((FAR struct ipv6_hdr_s *)&dev->d_buf[NET_LL_HDRLEN(dev)]) #define PAYLOAD ((FAR uint8_t *)&dev->d_buf[NET_LL_HDRLEN(dev)] + IPv6_HDRLEN) /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: ipv6_exthdr * * Description: * Return true if the next header value is an IPv6 extension header. * ****************************************************************************/ static bool ipv6_exthdr(uint8_t nxthdr) { switch (nxthdr) { case NEXT_HOPBYBOT_EH: /* Hop-by-Hop Options Header */ case NEXT_ENCAP_EH: /* Encapsulated IPv6 Header */ case NEXT_ROUTING_EH: /* Routing Header */ case NEXT_FRAGMENT_EH: /* Fragment Header */ case NEXT_RRSVP_EH: /* Resource ReSerVation Protocol */ case NEXT_ENCAPSEC_EH: /* Encapsulating Security Payload */ case NEXT_AUTH_EH: /* Authentication Header */ case NEXT_DESTOPT_EH: /* Destination Options Header */ case NEXT_MOBILITY_EH: /* Mobility */ case NEXT_HOSTID_EH: /* Host Identity Protocol */ case NEXT_SHIM6_EH: /* Shim6 Protocol */ return true; case NEXT_NOHEADER: /* No next header */ default: return false; } } /**************************************************************************** * Name: check_dev_destipaddr * * Description: * Check if the destination address in the IPv6 is destined for the * provided network device. * * Returned Value: * 1 - This packet is destined for this network device * 0 - This packet is NOT destined for this network device * ****************************************************************************/ static int check_dev_destipaddr(FAR struct net_driver_s *dev, FAR void *arg) { FAR struct ipv6_hdr_s *ipv6 = (FAR struct ipv6_hdr_s *)arg; /* Check if the IPv6 destination address matches the IPv6 address assigned * to this device. */ if (net_ipv6addr_cmp(ipv6->destipaddr, dev->d_ipv6addr)) { return 1; } /* No match, return 0 to keep searching */ return 0; } /**************************************************************************** * Name: check_destipaddr * * Description: * Check if the destination address in the IPv6 is destined for us. This * is typically just a comparison the of the IPv6 destination address in * the IPv6 packet with the IPv6 address assigned to the receiving device. * * Input Parameters: * dev - The device on which the packet was received and which contains * the IPv6 packet. * ipv6 - A convenience pointer to the IPv6 header in within the IPv6 * packet * * Returned Value: * true - This packet is destined for us * false - This packet is NOT destined for us and may need to be forwarded. * ****************************************************************************/ static bool check_destipaddr(FAR struct net_driver_s *dev, FAR struct ipv6_hdr_s *ipv6) { int ret; /* For IPv6, packet reception is a little trickier as we need to make sure * that we listen to certain multicast addresses (all hosts multicast * address, and the solicited-node multicast address) as well. However, * we will cheat here and accept all multicast packets that are sent to * the ff02::/16 addresses. */ if (ipv6->destipaddr[0] == HTONS(0xff02)) { #ifdef CONFIG_NET_IPFORWARD_BROADCAST /* Forward multicast packets */ ipv6_forward_broadcast(dev, ipv6); #endif return true; } /* We will also allow for a perverse case where we receive a packet * addressed to us, but on a different device. Can that really happen? */ ret = netdev_foreach(check_dev_destipaddr, ipv6); if (ret == 1) { /* The traversal of the network devices will return 0 if there is * no network device with that address or 1 if there is a network * device with such an address. */ return true; } return false; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: ipv6_input * * Description: * Receive an IPv6 packet from the network device. Verify and forward to * L3 packet handling logic if the packet is destined for us. * * Input Parameters: * dev - The device on which the packet was received and which contains * the IPv6 packet. * Returned Value: * OK - The packet was processed (or dropped) and can be discarded. * ERROR - Hold the packet and try again later. There is a listening * socket but no receive in place to catch the packet yet. The * device's d_len will be set to zero in this case as there is * no outgoing data. * * If this function returns to the network driver with dev->d_len > 0, * that is an indication to the driver that there is an outgoing response * to this input. * * Assumptions: * The network is locked. * ****************************************************************************/ int ipv6_input(FAR struct net_driver_s *dev) { FAR struct ipv6_hdr_s *ipv6 = IPv6BUF; FAR uint8_t *payload; uint16_t llhdrlen; uint16_t iphdrlen; uint16_t paylen; uint8_t nxthdr; #ifdef CONFIG_NET_IPFORWARD int ret; #endif /* This is where the input processing starts. */ #ifdef CONFIG_NET_STATISTICS g_netstats.ipv6.recv++; #endif /* Start of IP input header processing code. * * Check validity of the IP header. */ if ((ipv6->vtc & 0xf0) != 0x60) { /* IP version and header length. */ nwarn("WARNING: Invalid IPv6 version: %d\n", ipv6->vtc >> 4); #ifdef CONFIG_NET_STATISTICS g_netstats.ipv6.vhlerr++; #endif goto drop; } /* Get the size of the packet minus the size of link layer header */ llhdrlen = NET_LL_HDRLEN(dev); if ((llhdrlen + IPv6_HDRLEN) > dev->d_len) { nwarn("WARNING: Packet shorter than IPv6 header\n"); goto drop; } dev->d_len -= llhdrlen; /* Make sure that all packet processing logic knows that there is an IPv6 * packet in the device buffer. */ IFF_SET_IPv6(dev->d_flags); /* Check the size of the packet. If the size reported to us in d_len is * smaller the size reported in the IP header, we assume that the packet * has been corrupted in transit. If the size of d_len is larger than the * size reported in the IP packet header, the packet has been padded and * we set d_len to the correct value. * * The length reported in the IPv6 header is the length of the payload * that follows the header. The device interface uses the d_len variable * for holding the size of the entire packet, including the IP header but * without the link layer header (subtracted out above). * * NOTE: The payload length in the includes the size of the Ipv6 extension * options, but not the size of the IPv6 header. * * REVISIT: Length will be set to zero if the extension header carries * a Jumbo payload option. */ paylen = ((uint16_t)ipv6->len[0] << 8) + (uint16_t)ipv6->len[1] + IPv6_HDRLEN; if (paylen <= dev->d_len) { dev->d_len = paylen; } else { nwarn("WARNING: IP packet shorter than length in IP header\n"); goto drop; } /* Parse IPv6 extension headers (parsed but ignored) */ payload = PAYLOAD; /* Assume payload starts right after IPv6 header */ iphdrlen = IPv6_HDRLEN; /* Total length of the IPv6 header */ nxthdr = ipv6->proto; /* Next header determined by IPv6 header prototype */ while (ipv6_exthdr(nxthdr)) { FAR struct ipv6_extension_s *exthdr; uint16_t extlen; /* Just skip over the extension header */ exthdr = (FAR struct ipv6_extension_s *)payload; extlen = EXTHDR_LEN((unsigned int)exthdr->len); payload += extlen; iphdrlen += extlen; nxthdr = exthdr->nxthdr; } #ifdef CONFIG_NET_BROADCAST /* Check for a multicast packet, which may be destined to us (even if * there is no IP address yet assigned to the device). We only expect * multicast packets destined for sockets that have joined a multicast * group or for ICMPv6 Autoconfiguration and Neighbor discovery or ICMPv6 * MLD packets. * * We should actually pick off certain multicast address (all hosts * multicast address, and the solicited-node multicast address). We * will cheat here and accept all multicast packets that are sent to the * ff00::/8 addresses (see net_is_addr_mcast). */ if (net_is_addr_mcast(ipv6->destipaddr)) { #ifdef CONFIG_NET_IPFORWARD_BROADCAST /* Packets sent to ffx0 are reserved, ffx1 are interface-local, and * ffx2 are interface-local, and therefore, should not be forwarded */ if ((ipv6->destipaddr[0] & HTONS(0xff0f) != HTONS(0xff00)) && (ipv6->destipaddr[0] & HTONS(0xff0f) != HTONS(0xff01)) && (ipv6->destipaddr[0] & HTONS(0xff0f) != HTONS(0xff02))) { /* Forward broadcast packets */ ipv6_forward_broadcast(dev, ipv6); } #endif /* Fall through with no further address checks and handle the multicast * address by its IPv6 nexthdr field. */ } else #endif { /* Check if the packet is destined for us. */ if (!check_destipaddr(dev, ipv6)) { #ifdef CONFIG_NET_IPFORWARD /* Not destined for us, try to forward the packet */ ret = ipv6_forward(dev, ipv6); if (ret >= 0) { /* The packet was forwarded. Return success; d_len will * be set appropriately by the forwarding logic: Cleared * if the packet is forward via another device or non- * zero if it will be forwarded by the same device that * it was received on. */ return OK; } else #endif #if defined(NET_UDP_HAVE_STACK) && defined(CONFIG_NET_UDP_BINDTODEVICE) /* If the UDP protocol specific socket option UDP_BINDTODEVICE * is selected, then we must forward all UDP packets to the bound * socket. */ if (nxthdr != IP_PROTO_UDP || !IFF_IS_BOUND(dev->d_flags)) #endif { /* Not destined for us and not forwardable... * drop the packet. */ nwarn("WARNING: Not destined for us... Dropping!\n"); goto drop; } } } #ifdef CONFIG_NET_ICMPv6 /* In other cases, the device must be assigned a non-zero IP address * (the all zero address is the "unspecified" address. */ if (net_ipv6addr_cmp(dev->d_ipv6addr, g_ipv6_unspecaddr)) { nwarn("WARNING: No IP address assigned\n"); goto drop; } #endif /* Now process the incoming packet according to the protocol specified in * the next header IPv6 field. */ switch (nxthdr) { #ifdef NET_TCP_HAVE_STACK case IP_PROTO_TCP: /* TCP input */ /* Forward the IPv6 TCP packet */ tcp_ipv6_input(dev, iphdrlen); #ifdef CONFIG_NET_6LOWPAN /* TCP output comes through three different mechanisms. Either from: * * 1. TCP socket output. For the case of TCP output to an * IEEE802.15.4, the TCP output is caught in the socket * send()/sendto() logic and and redirected to 6LoWPAN logic. * 2. TCP output from the TCP state machine. That will occur * during TCP packet processing by the TCP state machine. * 3. TCP output resulting from TX or timer polling * * Case 3 is handled here. Logic here detects if (1) an attempt * to return with d_len > 0 and (2) that the device is an * IEEE802.15.4 MAC network driver. Under those conditions, 6LoWPAN * logic will be called to create the IEEE80215.4 frames. */ if (dev->d_len > 0 && dev->d_lltype == CONFIG_NET_6LOWPAN) { /* Let 6LoWPAN handle the TCP output */ sixlowpan_tcp_send(dev, dev, ipv6); /* Drop the packet in the d_buf */ goto drop; } #endif /* CONFIG_NET_6LOWPAN */ break; #endif /* NET_TCP_HAVE_STACK */ #ifdef NET_UDP_HAVE_STACK case IP_PROTO_UDP: /* UDP input */ /* Forward the IPv6 UDP packet */ udp_ipv6_input(dev, iphdrlen); break; #endif /* Check for ICMP input */ #ifdef NET_ICMPv6_HAVE_STACK case IP_PROTO_ICMP6: /* ICMP6 input */ /* Forward the ICMPv6 packet */ icmpv6_input(dev, iphdrlen); #ifdef CONFIG_NET_6LOWPAN /* All outgoing ICMPv6 messages come through one of two mechanisms: * * 1. The output from internal ICMPv6 message passing. These * outgoing messages will use device polling and will be * handled elsewhere. * 2. ICMPv6 output resulting from TX or timer polling. * * Case 2 is handled here. Logic here detects if (1) an attempt * to return with d_len > 0 and (2) that the device is an * IEEE802.15.4 MAC network driver. Under those conditions, 6LoWPAN * logic will be called to create the IEEE80215.4 frames. */ if (dev->d_len > 0 && dev->d_lltype == CONFIG_NET_6LOWPAN) { /* Let 6LoWPAN handle the ICMPv6 output */ sixlowpan_icmpv6_send(dev, dev, ipv6); /* Drop the packet in the d_buf */ goto drop; } #endif /* CONFIG_NET_6LOWPAN */ break; #endif /* NET_ICMPv6_HAVE_STACK */ default: /* Unrecognized/unsupported protocol */ nwarn("WARNING: Unrecognized IP protocol: %04x\n", ipv6->proto); #ifdef CONFIG_NET_STATISTICS g_netstats.ipv6.protoerr++; #endif goto drop; } /* Return and let the caller do any pending transmission. */ return OK; /* Drop the packet. NOTE that OK is returned meaning that the * packet has been processed (although processed unsuccessfully). */ drop: #ifdef CONFIG_NET_STATISTICS g_netstats.ipv6.drop++; #endif dev->d_len = 0; return OK; } #endif /* CONFIG_NET_IPv6 */