/* @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) | |
{ | |
/* no initializations as of yet */ | |
} | |
/** | |
* 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%lx found\n", | |
iphdr->dest.addr)); | |
snmp_inc_ipnoroutes(); | |
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_ipnoroutes(); | |
return (struct netif *)NULL; | |
} | |
/* decrement TTL */ | |
IPH_TTL_SET(iphdr, IPH_TTL(iphdr) - 1); | |
/* send ICMP if TTL == 0 */ | |
if (IPH_TTL(iphdr) == 0) { | |
/* Don't send ICMP messages in response to ICMP messages */ | |
if (IPH_PROTO(iphdr) != IP_PROTO_ICMP) { | |
icmp_time_exceeded(p, ICMP_TE_TTL); | |
snmp_inc_icmpouttimeexcds(); | |
} | |
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%lx\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 %u\n", IPH_V(iphdr))); | |
ip_debug_print(p); | |
pbuf_free(p); | |
IP_STATS_INC(ip.err); | |
IP_STATS_INC(ip.drop); | |
snmp_inc_ipunknownprotos(); | |
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 %u) does not fit in first pbuf (len %u), 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%x) 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_ipindiscards(); | |
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%lx netif->ip_addr 0x%lx (0x%lx, 0x%lx, 0x%lx)\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 %u\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_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%04x tot_len=%u len=%u MF=%u offset=%u), 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%x) (while IP_REASSEMBLY == 0).\n", | |
ntohs(IPH_OFFSET(iphdr)))); | |
IP_STATS_INC(ip.opterr); | |
IP_STATS_INC(ip.drop); | |
snmp_inc_ipunknownprotos(); | |
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); | |
snmp_inc_ipunknownprotos(); | |
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 %d p->tot_len %d\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 %d\n", IPH_PROTO(iphdr))); | |
IP_STATS_INC(ip.proterr); | |
IP_STATS_INC(ip.drop); | |
snmp_inc_ipunknownprotos(); | |
} | |
#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. | |
*/ | |
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; | |
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%u\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%lx\n", dest->addr)); | |
IP_STATS_INC(ip.rterr); | |
snmp_inc_ipoutdiscards(); | |
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, ("|%2d |%2d | 0x%02x | %5u | (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, ("| %5u |%u%u%u| %4u | (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, ("| %3u | %3u | 0x%04x | (ttl, proto, chksum)\n", | |
IPH_TTL(iphdr), | |
IPH_PROTO(iphdr), | |
ntohs(IPH_CHKSUM(iphdr)))); | |
LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n")); | |
LWIP_DEBUGF(IP_DEBUG, ("| %3u | %3u | %3u | %3u | (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, ("| %3u | %3u | %3u | %3u | (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 */ | |