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[/] [openrisc/] [trunk/] [rtos/] [freertos-6.1.1/] [Demo/] [Common/] [ethernet/] [lwIP/] [core/] [ipv4/] [ip.c] - Rev 622
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/* @file * * This is the IP layer implementation for incoming and outgoing IP traffic. * * @see ip_frag.c * */ /* * Copyright (c) 2001-2004 Swedish Institute of Computer Science. * 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. * * This file is part of the lwIP TCP/IP stack. * * Author: Adam Dunkels <adam@sics.se> * */ #include "lwip/opt.h" #include "lwip/def.h" #include "lwip/mem.h" #include "lwip/ip.h" #include "lwip/ip_frag.h" #include "lwip/inet.h" #include "lwip/netif.h" #include "lwip/icmp.h" #include "lwip/raw.h" #include "lwip/udp.h" #include "lwip/tcp.h" #include "lwip/stats.h" #include "arch/perf.h" #include "lwip/snmp.h" #if LWIP_DHCP # include "lwip/dhcp.h" #endif /* LWIP_DHCP */ /** * Initializes the IP layer. */ void ip_init(void) { #if IP_FRAG ip_frag_init(); #endif } /** * Finds the appropriate network interface for a given IP address. It * searches the list of network interfaces linearly. A match is found * if the masked IP address of the network interface equals the masked * IP address given to the function. */ struct netif * ip_route(struct ip_addr *dest) { struct netif *netif; /* iterate through netifs */ for(netif = netif_list; netif != NULL; netif = netif->next) { /* network mask matches? */ if (ip_addr_netcmp(dest, &(netif->ip_addr), &(netif->netmask))) { /* return netif on which to forward IP packet */ return netif; } } /* no matching netif found, use default netif */ return netif_default; } #if IP_FORWARD /** * Forwards an IP packet. It finds an appropriate route for the * packet, decrements the TTL value of the packet, adjusts the * checksum and outputs the packet on the appropriate interface. */ static struct netif * ip_forward(struct pbuf *p, struct ip_hdr *iphdr, struct netif *inp) { struct netif *netif; PERF_START; /* Find network interface where to forward this IP packet to. */ netif = ip_route((struct ip_addr *)&(iphdr->dest)); if (netif == NULL) { LWIP_DEBUGF(IP_DEBUG, ("ip_forward: no forwarding route for 0x%"X32_F" found\n", iphdr->dest.addr)); snmp_inc_ipoutnoroutes(); return (struct netif *)NULL; } /* Do not forward packets onto the same network interface on which * they arrived. */ if (netif == inp) { LWIP_DEBUGF(IP_DEBUG, ("ip_forward: not bouncing packets back on incoming interface.\n")); snmp_inc_ipoutnoroutes(); return (struct netif *)NULL; } /* decrement TTL */ IPH_TTL_SET(iphdr, IPH_TTL(iphdr) - 1); /* send ICMP if TTL == 0 */ if (IPH_TTL(iphdr) == 0) { snmp_inc_ipinhdrerrors(); /* Don't send ICMP messages in response to ICMP messages */ if (IPH_PROTO(iphdr) != IP_PROTO_ICMP) { icmp_time_exceeded(p, ICMP_TE_TTL); } return (struct netif *)NULL; } /* Incrementally update the IP checksum. */ if (IPH_CHKSUM(iphdr) >= htons(0xffff - 0x100)) { IPH_CHKSUM_SET(iphdr, IPH_CHKSUM(iphdr) + htons(0x100) + 1); } else { IPH_CHKSUM_SET(iphdr, IPH_CHKSUM(iphdr) + htons(0x100)); } LWIP_DEBUGF(IP_DEBUG, ("ip_forward: forwarding packet to 0x%"X32_F"\n", iphdr->dest.addr)); IP_STATS_INC(ip.fw); IP_STATS_INC(ip.xmit); snmp_inc_ipforwdatagrams(); PERF_STOP("ip_forward"); /* transmit pbuf on chosen interface */ netif->output(netif, p, (struct ip_addr *)&(iphdr->dest)); return netif; } #endif /* IP_FORWARD */ /** * This function is called by the network interface device driver when * an IP packet is received. The function does the basic checks of the * IP header such as packet size being at least larger than the header * size etc. If the packet was not destined for us, the packet is * forwarded (using ip_forward). The IP checksum is always checked. * * Finally, the packet is sent to the upper layer protocol input function. * * * */ err_t ip_input(struct pbuf *p, struct netif *inp) { struct ip_hdr *iphdr; struct netif *netif; u16_t iphdrlen; IP_STATS_INC(ip.recv); snmp_inc_ipinreceives(); /* identify the IP header */ iphdr = p->payload; if (IPH_V(iphdr) != 4) { LWIP_DEBUGF(IP_DEBUG | 1, ("IP packet dropped due to bad version number %"U16_F"\n", IPH_V(iphdr))); ip_debug_print(p); pbuf_free(p); IP_STATS_INC(ip.err); IP_STATS_INC(ip.drop); snmp_inc_ipinhdrerrors(); return ERR_OK; } /* obtain IP header length in number of 32-bit words */ iphdrlen = IPH_HL(iphdr); /* calculate IP header length in bytes */ iphdrlen *= 4; /* header length exceeds first pbuf length? */ if (iphdrlen > p->len) { LWIP_DEBUGF(IP_DEBUG | 2, ("IP header (len %"U16_F") does not fit in first pbuf (len %"U16_F"), IP packet droppped.\n", iphdrlen, p->len)); /* free (drop) packet pbufs */ pbuf_free(p); IP_STATS_INC(ip.lenerr); IP_STATS_INC(ip.drop); snmp_inc_ipindiscards(); return ERR_OK; } /* verify checksum */ #if CHECKSUM_CHECK_IP if (inet_chksum(iphdr, iphdrlen) != 0) { LWIP_DEBUGF(IP_DEBUG | 2, ("Checksum (0x%"X16_F") failed, IP packet dropped.\n", inet_chksum(iphdr, iphdrlen))); ip_debug_print(p); pbuf_free(p); IP_STATS_INC(ip.chkerr); IP_STATS_INC(ip.drop); snmp_inc_ipinhdrerrors(); return ERR_OK; } #endif /* Trim pbuf. This should have been done at the netif layer, * but we'll do it anyway just to be sure that its done. */ pbuf_realloc(p, ntohs(IPH_LEN(iphdr))); /* match packet against an interface, i.e. is this packet for us? */ for (netif = netif_list; netif != NULL; netif = netif->next) { LWIP_DEBUGF(IP_DEBUG, ("ip_input: iphdr->dest 0x%"X32_F" netif->ip_addr 0x%"X32_F" (0x%"X32_F", 0x%"X32_F", 0x%"X32_F")\n", iphdr->dest.addr, netif->ip_addr.addr, iphdr->dest.addr & netif->netmask.addr, netif->ip_addr.addr & netif->netmask.addr, iphdr->dest.addr & ~(netif->netmask.addr))); /* interface is up and configured? */ if ((netif_is_up(netif)) && (!ip_addr_isany(&(netif->ip_addr)))) { /* unicast to this interface address? */ if (ip_addr_cmp(&(iphdr->dest), &(netif->ip_addr)) || /* or broadcast on this interface network address? */ ip_addr_isbroadcast(&(iphdr->dest), netif)) { LWIP_DEBUGF(IP_DEBUG, ("ip_input: packet accepted on interface %c%c\n", netif->name[0], netif->name[1])); /* break out of for loop */ break; } } } #if LWIP_DHCP /* Pass DHCP messages regardless of destination address. DHCP traffic is addressed * using link layer addressing (such as Ethernet MAC) so we must not filter on IP. * According to RFC 1542 section 3.1.1, referred by RFC 2131). */ if (netif == NULL) { /* remote port is DHCP server? */ if (IPH_PROTO(iphdr) == IP_PROTO_UDP) { LWIP_DEBUGF(IP_DEBUG | DBG_TRACE | 1, ("ip_input: UDP packet to DHCP client port %"U16_F"\n", ntohs(((struct udp_hdr *)((u8_t *)iphdr + iphdrlen))->dest))); if (ntohs(((struct udp_hdr *)((u8_t *)iphdr + iphdrlen))->dest) == DHCP_CLIENT_PORT) { LWIP_DEBUGF(IP_DEBUG | DBG_TRACE | 1, ("ip_input: DHCP packet accepted.\n")); netif = inp; } } } #endif /* LWIP_DHCP */ /* packet not for us? */ if (netif == NULL) { /* packet not for us, route or discard */ LWIP_DEBUGF(IP_DEBUG | DBG_TRACE | 1, ("ip_input: packet not for us.\n")); #if IP_FORWARD /* non-broadcast packet? */ if (!ip_addr_isbroadcast(&(iphdr->dest), inp)) { /* try to forward IP packet on (other) interfaces */ ip_forward(p, iphdr, inp); } else #endif /* IP_FORWARD */ { snmp_inc_ipinaddrerrors(); snmp_inc_ipindiscards(); } pbuf_free(p); return ERR_OK; } /* packet consists of multiple fragments? */ if ((IPH_OFFSET(iphdr) & htons(IP_OFFMASK | IP_MF)) != 0) { #if IP_REASSEMBLY /* packet fragment reassembly code present? */ LWIP_DEBUGF(IP_DEBUG, ("IP packet is a fragment (id=0x%04"X16_F" tot_len=%"U16_F" len=%"U16_F" MF=%"U16_F" offset=%"U16_F"), calling ip_reass()\n", ntohs(IPH_ID(iphdr)), p->tot_len, ntohs(IPH_LEN(iphdr)), !!(IPH_OFFSET(iphdr) & htons(IP_MF)), (ntohs(IPH_OFFSET(iphdr)) & IP_OFFMASK)*8)); /* reassemble the packet*/ p = ip_reass(p); /* packet not fully reassembled yet? */ if (p == NULL) { return ERR_OK; } iphdr = p->payload; #else /* IP_REASSEMBLY == 0, no packet fragment reassembly code present */ pbuf_free(p); LWIP_DEBUGF(IP_DEBUG | 2, ("IP packet dropped since it was fragmented (0x%"X16_F") (while IP_REASSEMBLY == 0).\n", ntohs(IPH_OFFSET(iphdr)))); IP_STATS_INC(ip.opterr); IP_STATS_INC(ip.drop); /* unsupported protocol feature */ snmp_inc_ipinunknownprotos(); return ERR_OK; #endif /* IP_REASSEMBLY */ } #if IP_OPTIONS == 0 /* no support for IP options in the IP header? */ if (iphdrlen > IP_HLEN) { LWIP_DEBUGF(IP_DEBUG | 2, ("IP packet dropped since there were IP options (while IP_OPTIONS == 0).\n")); pbuf_free(p); IP_STATS_INC(ip.opterr); IP_STATS_INC(ip.drop); /* unsupported protocol feature */ snmp_inc_ipinunknownprotos(); return ERR_OK; } #endif /* IP_OPTIONS == 0 */ /* send to upper layers */ LWIP_DEBUGF(IP_DEBUG, ("ip_input: \n")); ip_debug_print(p); LWIP_DEBUGF(IP_DEBUG, ("ip_input: p->len %"U16_F" p->tot_len %"U16_F"\n", p->len, p->tot_len)); #if LWIP_RAW /* raw input did not eat the packet? */ if (raw_input(p, inp) == 0) { #endif /* LWIP_RAW */ switch (IPH_PROTO(iphdr)) { #if LWIP_UDP case IP_PROTO_UDP: case IP_PROTO_UDPLITE: snmp_inc_ipindelivers(); udp_input(p, inp); break; #endif /* LWIP_UDP */ #if LWIP_TCP case IP_PROTO_TCP: snmp_inc_ipindelivers(); tcp_input(p, inp); break; #endif /* LWIP_TCP */ case IP_PROTO_ICMP: snmp_inc_ipindelivers(); icmp_input(p, inp); break; default: /* send ICMP destination protocol unreachable unless is was a broadcast */ if (!ip_addr_isbroadcast(&(iphdr->dest), inp) && !ip_addr_ismulticast(&(iphdr->dest))) { p->payload = iphdr; icmp_dest_unreach(p, ICMP_DUR_PROTO); } pbuf_free(p); LWIP_DEBUGF(IP_DEBUG | 2, ("Unsupported transport protocol %"U16_F"\n", IPH_PROTO(iphdr))); IP_STATS_INC(ip.proterr); IP_STATS_INC(ip.drop); snmp_inc_ipinunknownprotos(); } #if LWIP_RAW } /* LWIP_RAW */ #endif return ERR_OK; } /** * Sends an IP packet on a network interface. This function constructs * the IP header and calculates the IP header checksum. If the source * IP address is NULL, the IP address of the outgoing network * interface is filled in as source address. * * @note ip_id: RFC791 "some host may be able to simply use * unique identifiers independent of destination" */ err_t ip_output_if(struct pbuf *p, struct ip_addr *src, struct ip_addr *dest, u8_t ttl, u8_t tos, u8_t proto, struct netif *netif) { struct ip_hdr *iphdr; static u16_t ip_id = 0; snmp_inc_ipoutrequests(); if (dest != IP_HDRINCL) { if (pbuf_header(p, IP_HLEN)) { LWIP_DEBUGF(IP_DEBUG | 2, ("ip_output: not enough room for IP header in pbuf\n")); IP_STATS_INC(ip.err); snmp_inc_ipoutdiscards(); return ERR_BUF; } iphdr = p->payload; IPH_TTL_SET(iphdr, ttl); IPH_PROTO_SET(iphdr, proto); ip_addr_set(&(iphdr->dest), dest); IPH_VHLTOS_SET(iphdr, 4, IP_HLEN / 4, tos); IPH_LEN_SET(iphdr, htons(p->tot_len)); IPH_OFFSET_SET(iphdr, htons(IP_DF)); IPH_ID_SET(iphdr, htons(ip_id)); ++ip_id; if (ip_addr_isany(src)) { ip_addr_set(&(iphdr->src), &(netif->ip_addr)); } else { ip_addr_set(&(iphdr->src), src); } IPH_CHKSUM_SET(iphdr, 0); #if CHECKSUM_GEN_IP IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN)); #endif } else { iphdr = p->payload; dest = &(iphdr->dest); } #if IP_FRAG /* don't fragment if interface has mtu set to 0 [loopif] */ if (netif->mtu && (p->tot_len > netif->mtu)) return ip_frag(p,netif,dest); #endif IP_STATS_INC(ip.xmit); LWIP_DEBUGF(IP_DEBUG, ("ip_output_if: %c%c%"U16_F"\n", netif->name[0], netif->name[1], netif->num)); ip_debug_print(p); LWIP_DEBUGF(IP_DEBUG, ("netif->output()")); return netif->output(netif, p, dest); } /** * Simple interface to ip_output_if. It finds the outgoing network * interface and calls upon ip_output_if to do the actual work. */ err_t ip_output(struct pbuf *p, struct ip_addr *src, struct ip_addr *dest, u8_t ttl, u8_t tos, u8_t proto) { struct netif *netif; if ((netif = ip_route(dest)) == NULL) { LWIP_DEBUGF(IP_DEBUG | 2, ("ip_output: No route to 0x%"X32_F"\n", dest->addr)); IP_STATS_INC(ip.rterr); snmp_inc_ipoutnoroutes(); return ERR_RTE; } return ip_output_if(p, src, dest, ttl, tos, proto, netif); } #if IP_DEBUG void ip_debug_print(struct pbuf *p) { struct ip_hdr *iphdr = p->payload; u8_t *payload; payload = (u8_t *)iphdr + IP_HLEN; LWIP_DEBUGF(IP_DEBUG, ("IP header:\n")); LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n")); LWIP_DEBUGF(IP_DEBUG, ("|%2"S16_F" |%2"S16_F" | 0x%02"X16_F" | %5"U16_F" | (v, hl, tos, len)\n", IPH_V(iphdr), IPH_HL(iphdr), IPH_TOS(iphdr), ntohs(IPH_LEN(iphdr)))); LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n")); LWIP_DEBUGF(IP_DEBUG, ("| %5"U16_F" |%"U16_F"%"U16_F"%"U16_F"| %4"U16_F" | (id, flags, offset)\n", ntohs(IPH_ID(iphdr)), ntohs(IPH_OFFSET(iphdr)) >> 15 & 1, ntohs(IPH_OFFSET(iphdr)) >> 14 & 1, ntohs(IPH_OFFSET(iphdr)) >> 13 & 1, ntohs(IPH_OFFSET(iphdr)) & IP_OFFMASK)); LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n")); LWIP_DEBUGF(IP_DEBUG, ("| %3"U16_F" | %3"U16_F" | 0x%04"X16_F" | (ttl, proto, chksum)\n", IPH_TTL(iphdr), IPH_PROTO(iphdr), ntohs(IPH_CHKSUM(iphdr)))); LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n")); LWIP_DEBUGF(IP_DEBUG, ("| %3"U16_F" | %3"U16_F" | %3"U16_F" | %3"U16_F" | (src)\n", ip4_addr1(&iphdr->src), ip4_addr2(&iphdr->src), ip4_addr3(&iphdr->src), ip4_addr4(&iphdr->src))); LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n")); LWIP_DEBUGF(IP_DEBUG, ("| %3"U16_F" | %3"U16_F" | %3"U16_F" | %3"U16_F" | (dest)\n", ip4_addr1(&iphdr->dest), ip4_addr2(&iphdr->dest), ip4_addr3(&iphdr->dest), ip4_addr4(&iphdr->dest))); LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n")); } #endif /* IP_DEBUG */
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