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esp-idf/components/lwip/core/ipv4/ip4.c
XiaXiaotian 7a64e19ba8 Broadcast IP route based on source IP address. 
If destination IP address of the packet is broadcast address, firstly compare
    source IP address with the that of each network interface. If it matches,
    packet is forwarded from the interface.
2017-06-30 16:18:29 +08:00

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/**
* @file
* This is the IPv4 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"
#if LWIP_IPV4
#include "lwip/ip.h"
#include "lwip/def.h"
#include "lwip/mem.h"
#include "lwip/ip_frag.h"
#include "lwip/inet_chksum.h"
#include "lwip/netif.h"
#include "lwip/icmp.h"
#include "lwip/igmp.h"
#include "lwip/raw.h"
#include "lwip/udp.h"
#include "lwip/priv/tcp_priv.h"
#include "lwip/dhcp.h"
#include "lwip/autoip.h"
#include "lwip/stats.h"
#include <string.h>
/** Set this to 0 in the rare case of wanting to call an extra function to
* generate the IP checksum (in contrast to calculating it on-the-fly). */
#ifndef LWIP_INLINE_IP_CHKSUM
#if LWIP_CHECKSUM_CTRL_PER_NETIF
#define LWIP_INLINE_IP_CHKSUM 0
#else /* LWIP_CHECKSUM_CTRL_PER_NETIF */
#define LWIP_INLINE_IP_CHKSUM 1
#endif /* LWIP_CHECKSUM_CTRL_PER_NETIF */
#endif
#if LWIP_INLINE_IP_CHKSUM && CHECKSUM_GEN_IP
#define CHECKSUM_GEN_IP_INLINE 1
#else
#define CHECKSUM_GEN_IP_INLINE 0
#endif
#if LWIP_DHCP || defined(LWIP_IP_ACCEPT_UDP_PORT)
#define IP_ACCEPT_LINK_LAYER_ADDRESSING 1
/** Some defines for DHCP to let link-layer-addressed packets through while the
* netif is down.
* To use this in your own application/protocol, define LWIP_IP_ACCEPT_UDP_PORT(port)
* to return 1 if the port is accepted and 0 if the port is not accepted.
*/
#if LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT)
/* accept DHCP client port and custom port */
#define IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(port) (((port) == PP_NTOHS(DHCP_CLIENT_PORT)) \
|| (LWIP_IP_ACCEPT_UDP_PORT(port)))
#elif defined(LWIP_IP_ACCEPT_UDP_PORT) /* LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT) */
/* accept custom port only */
#define IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(port) (LWIP_IP_ACCEPT_UDP_PORT(port))
#else /* LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT) */
/* accept DHCP client port only */
#define IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(port) ((port) == PP_NTOHS(DHCP_CLIENT_PORT))
#endif /* LWIP_DHCP && defined(LWIP_IP_ACCEPT_UDP_PORT) */
#else /* LWIP_DHCP */
#define IP_ACCEPT_LINK_LAYER_ADDRESSING 0
#endif /* LWIP_DHCP */
/** The IP header ID of the next outgoing IP packet */
static u16_t ip_id;
#if LWIP_MULTICAST_TX_OPTIONS
/** The default netif used for multicast */
static struct netif* ip4_default_multicast_netif;
/** Set a default netif for IPv4 multicast. */
void
ip4_set_default_multicast_netif(struct netif* default_multicast_netif)
{
ip4_default_multicast_netif = default_multicast_netif;
}
#endif /* LWIP_MULTICAST_TX_OPTIONS */
#ifdef LWIP_HOOK_IP4_ROUTE_SRC
/**
* Source based IPv4 routing hook function. This function works only
* when destination IP is broadcast IP.
*/
struct netif *
ip4_route_src_hook(const ip4_addr_t *dest, const ip4_addr_t *src)
{
struct netif *netif = NULL;
/* destination IP is broadcast IP? */
if ((src != NULL) && (dest->addr == IPADDR_BROADCAST)) {
/* iterate through netifs */
for (netif = netif_list; netif != NULL; netif = netif->next) {
/* is the netif up, does it have a link and a valid address? */
if (netif_is_up(netif) && netif_is_link_up(netif) && !ip4_addr_isany_val(*netif_ip4_addr(netif))) {
/* source IP matches? */
if (ip4_addr_cmp(src, netif_ip4_addr(netif))) {
/* return netif on which to forward IP packet */
return netif;
}
}
}
}
return netif;
}
/**
* Source based IPv4 routing must be fully implemented in
* LWIP_HOOK_IP4_ROUTE_SRC(). This function only provides the parameters.
*/
struct netif *
ip4_route_src(const ip4_addr_t *dest, const ip4_addr_t *src)
{
if (src != NULL) {
/* when src==NULL, the hook is called from ip4_route(dest) */
struct netif *netif = LWIP_HOOK_IP4_ROUTE_SRC(dest, src);
if (netif != NULL) {
return netif;
}
}
return ip4_route(dest);
}
#endif /* LWIP_HOOK_IP4_ROUTE_SRC */
/**
* 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.
*
* @param dest the destination IP address for which to find the route
* @return the netif on which to send to reach dest
*/
struct netif *
ip4_route(const ip4_addr_t *dest)
{
#if ESP_LWIP
struct netif *non_default_netif = NULL;
#if LWIP_HAVE_LOOPIF
struct netif *loop_default_netif = netif_find("lo0");
#endif
#endif
struct netif *netif;
#if LWIP_MULTICAST_TX_OPTIONS
/* Use administratively selected interface for multicast by default */
if (ip4_addr_ismulticast(dest) && ip4_default_multicast_netif) {
return ip4_default_multicast_netif;
}
#endif /* LWIP_MULTICAST_TX_OPTIONS */
/* iterate through netifs */
for (netif = netif_list; netif != NULL; netif = netif->next) {
/* is the netif up, does it have a link and a valid address? */
if (netif_is_up(netif) && netif_is_link_up(netif) && !ip4_addr_isany_val(*netif_ip4_addr(netif))) {
/* network mask matches? */
if (ip4_addr_netcmp(dest, netif_ip4_addr(netif), netif_ip4_netmask(netif))) {
/* return netif on which to forward IP packet */
return netif;
}
/* gateway matches on a non broadcast interface? (i.e. peer in a point to point interface) */
if (((netif->flags & NETIF_FLAG_BROADCAST) == 0) && ip4_addr_cmp(dest, netif_ip4_gw(netif))) {
/* return netif on which to forward IP packet */
return netif;
}
if (netif != netif_default){
#if LWIP_HAVE_LOOPIF
non_default_netif = (netif == loop_default_netif) ? NULL : netif;
#else
non_default_netif = netif;
#endif
}
}
}
#if ESP_LWIP
if (non_default_netif && !ip4_addr_isbroadcast(dest, non_default_netif)){
return non_default_netif;
}
#endif
#if LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF
/* loopif is disabled, looopback traffic is passed through any netif */
if (ip4_addr_isloopback(dest)) {
/* don't check for link on loopback traffic */
if (netif_is_up(netif_default)) {
return netif_default;
}
/* default netif is not up, just use any netif for loopback traffic */
for (netif = netif_list; netif != NULL; netif = netif->next) {
if (netif_is_up(netif)) {
return netif;
}
}
return NULL;
}
#endif /* LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF */
#ifdef LWIP_HOOK_IP4_ROUTE_SRC
netif = LWIP_HOOK_IP4_ROUTE_SRC(dest, NULL);
if (netif != NULL) {
return netif;
}
#elif defined(LWIP_HOOK_IP4_ROUTE)
netif = LWIP_HOOK_IP4_ROUTE(dest);
if (netif != NULL) {
return netif;
}
#endif
if ((netif_default == NULL) || !netif_is_up(netif_default) || !netif_is_link_up(netif_default) ||
ip4_addr_isany_val(*netif_ip4_addr(netif_default))) {
/* No matching netif found and default netif is not usable.
If this is not good enough for you, use LWIP_HOOK_IP4_ROUTE() */
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip4_route: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest)));
IP_STATS_INC(ip.rterr);
MIB2_STATS_INC(mib2.ipoutnoroutes);
return NULL;
}
return netif_default;
}
#if IP_FORWARD
/**
* Determine whether an IP address is in a reserved set of addresses
* that may not be forwarded, or whether datagrams to that destination
* may be forwarded.
* @param p the packet to forward
* @param dest the destination IP address
* @return 1: can forward 0: discard
*/
static int
ip4_canforward(struct pbuf *p)
{
u32_t addr = htonl(ip4_addr_get_u32(ip4_current_dest_addr()));
if (p->flags & PBUF_FLAG_LLBCAST) {
/* don't route link-layer broadcasts */
return 0;
}
if ((p->flags & PBUF_FLAG_LLMCAST) && !IP_MULTICAST(addr)) {
/* don't route link-layer multicasts unless the destination address is an IP
multicast address */
return 0;
}
if (IP_EXPERIMENTAL(addr)) {
return 0;
}
if (IP_CLASSA(addr)) {
u32_t net = addr & IP_CLASSA_NET;
if ((net == 0) || (net == ((u32_t)IP_LOOPBACKNET << IP_CLASSA_NSHIFT))) {
/* don't route loopback packets */
return 0;
}
}
return 1;
}
/**
* 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.
*
* @param p the packet to forward (p->payload points to IP header)
* @param iphdr the IP header of the input packet
* @param inp the netif on which this packet was received
*/
static void
ip4_forward(struct pbuf *p, struct ip_hdr *iphdr, struct netif *inp)
{
struct netif *netif;
PERF_START;
if (!ip4_canforward(p)) {
goto return_noroute;
}
/* RFC3927 2.7: do not forward link-local addresses */
if (ip4_addr_islinklocal(ip4_current_dest_addr())) {
LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: not forwarding LLA %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
ip4_addr1_16(ip4_current_dest_addr()), ip4_addr2_16(ip4_current_dest_addr()),
ip4_addr3_16(ip4_current_dest_addr()), ip4_addr4_16(ip4_current_dest_addr())));
goto return_noroute;
}
/* Find network interface where to forward this IP packet to. */
netif = ip4_route_src(ip4_current_dest_addr(), ip4_current_src_addr());
if (netif == NULL) {
LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: no forwarding route for %"U16_F".%"U16_F".%"U16_F".%"U16_F" found\n",
ip4_addr1_16(ip4_current_dest_addr()), ip4_addr2_16(ip4_current_dest_addr()),
ip4_addr3_16(ip4_current_dest_addr()), ip4_addr4_16(ip4_current_dest_addr())));
/* @todo: send ICMP_DUR_NET? */
goto return_noroute;
}
#if !IP_FORWARD_ALLOW_TX_ON_RX_NETIF
/* Do not forward packets onto the same network interface on which
* they arrived. */
if (netif == inp) {
LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: not bouncing packets back on incoming interface.\n"));
goto return_noroute;
}
#endif /* IP_FORWARD_ALLOW_TX_ON_RX_NETIF */
/* decrement TTL */
IPH_TTL_SET(iphdr, IPH_TTL(iphdr) - 1);
/* send ICMP if TTL == 0 */
if (IPH_TTL(iphdr) == 0) {
MIB2_STATS_INC(mib2.ipinhdrerrors);
#if LWIP_ICMP
/* Don't send ICMP messages in response to ICMP messages */
if (IPH_PROTO(iphdr) != IP_PROTO_ICMP) {
icmp_time_exceeded(p, ICMP_TE_TTL);
}
#endif /* LWIP_ICMP */
return;
}
/* Incrementally update the IP checksum. */
if (IPH_CHKSUM(iphdr) >= PP_HTONS(0xffffU - 0x100)) {
IPH_CHKSUM_SET(iphdr, IPH_CHKSUM(iphdr) + PP_HTONS(0x100) + 1);
} else {
IPH_CHKSUM_SET(iphdr, IPH_CHKSUM(iphdr) + PP_HTONS(0x100));
}
LWIP_DEBUGF(IP_DEBUG, ("ip4_forward: forwarding packet to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
ip4_addr1_16(ip4_current_dest_addr()), ip4_addr2_16(ip4_current_dest_addr()),
ip4_addr3_16(ip4_current_dest_addr()), ip4_addr4_16(ip4_current_dest_addr())));
IP_STATS_INC(ip.fw);
MIB2_STATS_INC(mib2.ipforwdatagrams);
IP_STATS_INC(ip.xmit);
PERF_STOP("ip4_forward");
/* don't fragment if interface has mtu set to 0 [loopif] */
if (netif->mtu && (p->tot_len > netif->mtu)) {
if ((IPH_OFFSET(iphdr) & PP_NTOHS(IP_DF)) == 0) {
#if IP_FRAG
ip4_frag(p, netif, ip4_current_dest_addr());
#else /* IP_FRAG */
/* @todo: send ICMP Destination Unreachable code 13 "Communication administratively prohibited"? */
#endif /* IP_FRAG */
} else {
#if LWIP_ICMP
/* send ICMP Destination Unreachable code 4: "Fragmentation Needed and DF Set" */
icmp_dest_unreach(p, ICMP_DUR_FRAG);
#endif /* LWIP_ICMP */
}
return;
}
/* transmit pbuf on chosen interface */
netif->output(netif, p, ip4_current_dest_addr());
return;
return_noroute:
MIB2_STATS_INC(mib2.ipoutnoroutes);
}
#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.
*
* @param p the received IP packet (p->payload points to IP header)
* @param inp the netif on which this packet was received
* @return ERR_OK if the packet was processed (could return ERR_* if it wasn't
* processed, but currently always returns ERR_OK)
*/
err_t
ip4_input(struct pbuf *p, struct netif *inp)
{
struct ip_hdr *iphdr;
struct netif *netif;
u16_t iphdr_hlen;
u16_t iphdr_len;
#if IP_ACCEPT_LINK_LAYER_ADDRESSING || LWIP_IGMP
int check_ip_src = 1;
#endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING || LWIP_IGMP */
IP_STATS_INC(ip.recv);
MIB2_STATS_INC(mib2.ipinreceives);
/* identify the IP header */
iphdr = (struct ip_hdr *)p->payload;
if (IPH_V(iphdr) != 4) {
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_WARNING, ("IP packet dropped due to bad version number %"U16_F"\n", IPH_V(iphdr)));
ip4_debug_print(p);
pbuf_free(p);
IP_STATS_INC(ip.err);
IP_STATS_INC(ip.drop);
MIB2_STATS_INC(mib2.ipinhdrerrors);
return ERR_OK;
}
#ifdef LWIP_HOOK_IP4_INPUT
if (LWIP_HOOK_IP4_INPUT(p, inp)) {
/* the packet has been eaten */
return ERR_OK;
}
#endif
/* obtain IP header length in number of 32-bit words */
iphdr_hlen = IPH_HL(iphdr);
/* calculate IP header length in bytes */
iphdr_hlen *= 4;
/* obtain ip length in bytes */
iphdr_len = ntohs(IPH_LEN(iphdr));
/* Trim pbuf. This is especially required for packets < 60 bytes. */
if (iphdr_len < p->tot_len) {
pbuf_realloc(p, iphdr_len);
}
/* header length exceeds first pbuf length, or ip length exceeds total pbuf length? */
if ((iphdr_hlen > p->len) || (iphdr_len > p->tot_len)) {
if (iphdr_hlen > p->len) {
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
("IP header (len %"U16_F") does not fit in first pbuf (len %"U16_F"), IP packet dropped.\n",
iphdr_hlen, p->len));
}
if (iphdr_len > p->tot_len) {
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
("IP (len %"U16_F") is longer than pbuf (len %"U16_F"), IP packet dropped.\n",
iphdr_len, p->tot_len));
}
/* free (drop) packet pbufs */
pbuf_free(p);
IP_STATS_INC(ip.lenerr);
IP_STATS_INC(ip.drop);
MIB2_STATS_INC(mib2.ipindiscards);
return ERR_OK;
}
/* verify checksum */
#if CHECKSUM_CHECK_IP
IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_CHECK_IP) {
if (inet_chksum(iphdr, iphdr_hlen) != 0) {
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
("Checksum (0x%"X16_F") failed, IP packet dropped.\n", inet_chksum(iphdr, iphdr_hlen)));
ip4_debug_print(p);
pbuf_free(p);
IP_STATS_INC(ip.chkerr);
IP_STATS_INC(ip.drop);
MIB2_STATS_INC(mib2.ipinhdrerrors);
return ERR_OK;
}
}
#endif
/* copy IP addresses to aligned ip_addr_t */
ip_addr_copy_from_ip4(ip_data.current_iphdr_dest, iphdr->dest);
ip_addr_copy_from_ip4(ip_data.current_iphdr_src, iphdr->src);
/* match packet against an interface, i.e. is this packet for us? */
if (ip4_addr_ismulticast(ip4_current_dest_addr())) {
#if LWIP_IGMP
if ((inp->flags & NETIF_FLAG_IGMP) && (igmp_lookfor_group(inp, ip4_current_dest_addr()))) {
/* IGMP snooping switches need 0.0.0.0 to be allowed as source address (RFC 4541) */
ip4_addr_t allsystems;
IP4_ADDR(&allsystems, 224, 0, 0, 1);
if (ip4_addr_cmp(ip4_current_dest_addr(), &allsystems) &&
ip4_addr_isany(ip4_current_src_addr())) {
check_ip_src = 0;
}
netif = inp;
} else {
netif = NULL;
}
#else /* LWIP_IGMP */
if ((netif_is_up(inp)) && (!ip4_addr_isany_val(*netif_ip4_addr(inp)))) {
netif = inp;
} else {
netif = NULL;
}
#endif /* LWIP_IGMP */
} else {
/* start trying with inp. if that's not acceptable, start walking the
list of configured netifs.
'first' is used as a boolean to mark whether we started walking the list */
int first = 1;
netif = inp;
do {
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",
ip4_addr_get_u32(&iphdr->dest), ip4_addr_get_u32(netif_ip4_addr(netif)),
ip4_addr_get_u32(&iphdr->dest) & ip4_addr_get_u32(netif_ip4_netmask(netif)),
ip4_addr_get_u32(netif_ip4_addr(netif)) & ip4_addr_get_u32(netif_ip4_netmask(netif)),
ip4_addr_get_u32(&iphdr->dest) & ~ip4_addr_get_u32(netif_ip4_netmask(netif))));
/* interface is up and configured? */
if ((netif_is_up(netif)) && (!ip4_addr_isany_val(*netif_ip4_addr(netif)))) {
/* unicast to this interface address? */
if (ip4_addr_cmp(ip4_current_dest_addr(), netif_ip4_addr(netif)) ||
/* or broadcast on this interface network address? */
ip4_addr_isbroadcast(ip4_current_dest_addr(), netif)
#if LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF
|| (ip4_addr_get_u32(ip4_current_dest_addr()) == PP_HTONL(IPADDR_LOOPBACK))
#endif /* LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF */
) {
LWIP_DEBUGF(IP_DEBUG, ("ip4_input: packet accepted on interface %c%c\n",
netif->name[0], netif->name[1]));
/* break out of for loop */
break;
}
#if LWIP_AUTOIP
/* connections to link-local addresses must persist after changing
the netif's address (RFC3927 ch. 1.9) */
if ((netif->autoip != NULL) &&
ip4_addr_cmp(ip4_current_dest_addr(), &(netif->autoip->llipaddr))) {
LWIP_DEBUGF(IP_DEBUG, ("ip4_input: LLA packet accepted on interface %c%c\n",
netif->name[0], netif->name[1]));
/* break out of for loop */
break;
}
#endif /* LWIP_AUTOIP */
}
if (first) {
first = 0;
netif = netif_list;
} else {
netif = netif->next;
}
if (netif == inp) {
netif = netif->next;
}
} while (netif != NULL);
}
#if IP_ACCEPT_LINK_LAYER_ADDRESSING
/* 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 you want to accept private broadcast communication while a netif is down,
* define LWIP_IP_ACCEPT_UDP_PORT(dst_port), e.g.:
*
* #define LWIP_IP_ACCEPT_UDP_PORT(dst_port) ((dst_port) == PP_NTOHS(12345))
*/
if (netif == NULL) {
/* remote port is DHCP server? */
if (IPH_PROTO(iphdr) == IP_PROTO_UDP) {
struct udp_hdr *udphdr = (struct udp_hdr *)((u8_t *)iphdr + iphdr_hlen);
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip4_input: UDP packet to DHCP client port %"U16_F"\n",
ntohs(udphdr->dest)));
if (IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(udphdr->dest)) {
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip4_input: DHCP packet accepted.\n"));
netif = inp;
check_ip_src = 0;
}
}
}
#endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING */
/* broadcast or multicast packet source address? Compliant with RFC 1122: 3.2.1.3 */
#if LWIP_IGMP || IP_ACCEPT_LINK_LAYER_ADDRESSING
if (check_ip_src
#if IP_ACCEPT_LINK_LAYER_ADDRESSING
/* DHCP servers need 0.0.0.0 to be allowed as source address (RFC 1.1.2.2: 3.2.1.3/a) */
&& !ip4_addr_isany_val(*ip4_current_src_addr())
#endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING */
)
#endif /* LWIP_IGMP || IP_ACCEPT_LINK_LAYER_ADDRESSING */
{
if ((ip4_addr_isbroadcast(ip4_current_src_addr(), inp)) ||
(ip4_addr_ismulticast(ip4_current_src_addr()))) {
/* packet source is not valid */
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("ip4_input: packet source is not valid.\n"));
/* free (drop) packet pbufs */
pbuf_free(p);
IP_STATS_INC(ip.drop);
MIB2_STATS_INC(mib2.ipinaddrerrors);
MIB2_STATS_INC(mib2.ipindiscards);
return ERR_OK;
}
}
/* packet not for us? */
if (netif == NULL) {
/* packet not for us, route or discard */
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip4_input: packet not for us.\n"));
#if IP_FORWARD
/* non-broadcast packet? */
if (!ip4_addr_isbroadcast(ip4_current_dest_addr(), inp)) {
/* try to forward IP packet on (other) interfaces */
ip4_forward(p, iphdr, inp);
} else
#endif /* IP_FORWARD */
{
MIB2_STATS_INC(mib2.ipinaddrerrors);
MIB2_STATS_INC(mib2.ipindiscards);
}
pbuf_free(p);
return ERR_OK;
}
/* packet consists of multiple fragments? */
if ((IPH_OFFSET(iphdr) & PP_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 ip4_reass()\n",
ntohs(IPH_ID(iphdr)), p->tot_len, ntohs(IPH_LEN(iphdr)), !!(IPH_OFFSET(iphdr) & PP_HTONS(IP_MF)), (ntohs(IPH_OFFSET(iphdr)) & IP_OFFMASK)*8));
/* reassemble the packet*/
p = ip4_reass(p);
/* packet not fully reassembled yet? */
if (p == NULL) {
return ERR_OK;
}
iphdr = (struct ip_hdr *)p->payload;
#else /* IP_REASSEMBLY == 0, no packet fragment reassembly code present */
pbuf_free(p);
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("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 */
MIB2_STATS_INC(mib2.ipinunknownprotos);
return ERR_OK;
#endif /* IP_REASSEMBLY */
}
#if IP_OPTIONS_ALLOWED == 0 /* no support for IP options in the IP header? */
#if LWIP_IGMP
/* there is an extra "router alert" option in IGMP messages which we allow for but do not police */
if ((iphdr_hlen > IP_HLEN) && (IPH_PROTO(iphdr) != IP_PROTO_IGMP)) {
#else
if (iphdr_hlen > IP_HLEN) {
#endif /* LWIP_IGMP */
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("IP packet dropped since there were IP options (while IP_OPTIONS_ALLOWED == 0).\n"));
pbuf_free(p);
IP_STATS_INC(ip.opterr);
IP_STATS_INC(ip.drop);
/* unsupported protocol feature */
MIB2_STATS_INC(mib2.ipinunknownprotos);
return ERR_OK;
}
#endif /* IP_OPTIONS_ALLOWED == 0 */
/* send to upper layers */
LWIP_DEBUGF(IP_DEBUG, ("ip4_input: \n"));
ip4_debug_print(p);
LWIP_DEBUGF(IP_DEBUG, ("ip4_input: p->len %"U16_F" p->tot_len %"U16_F"\n", p->len, p->tot_len));
ip_data.current_netif = netif;
ip_data.current_input_netif = inp;
ip_data.current_ip4_header = iphdr;
ip_data.current_ip_header_tot_len = IPH_HL(iphdr) * 4;
#if LWIP_RAW
/* raw input did not eat the packet? */
if (raw_input(p, inp) == 0)
#endif /* LWIP_RAW */
{
pbuf_header(p, -(s16_t)iphdr_hlen); /* Move to payload, no check necessary. */
switch (IPH_PROTO(iphdr)) {
#if LWIP_UDP
case IP_PROTO_UDP:
#if LWIP_UDPLITE
case IP_PROTO_UDPLITE:
#endif /* LWIP_UDPLITE */
MIB2_STATS_INC(mib2.ipindelivers);
udp_input(p, inp);
break;
#endif /* LWIP_UDP */
#if LWIP_TCP
case IP_PROTO_TCP:
MIB2_STATS_INC(mib2.ipindelivers);
tcp_input(p, inp);
break;
#endif /* LWIP_TCP */
#if LWIP_ICMP
case IP_PROTO_ICMP:
MIB2_STATS_INC(mib2.ipindelivers);
icmp_input(p, inp);
break;
#endif /* LWIP_ICMP */
#if LWIP_IGMP
case IP_PROTO_IGMP:
igmp_input(p, inp, ip4_current_dest_addr());
break;
#endif /* LWIP_IGMP */
default:
#if LWIP_ICMP
/* send ICMP destination protocol unreachable unless is was a broadcast */
if (!ip4_addr_isbroadcast(ip4_current_dest_addr(), netif) &&
!ip4_addr_ismulticast(ip4_current_dest_addr())) {
pbuf_header_force(p, iphdr_hlen); /* Move to ip header, no check necessary. */
p->payload = iphdr;
icmp_dest_unreach(p, ICMP_DUR_PROTO);
}
#endif /* LWIP_ICMP */
pbuf_free(p);
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("Unsupported transport protocol %"U16_F"\n", IPH_PROTO(iphdr)));
IP_STATS_INC(ip.proterr);
IP_STATS_INC(ip.drop);
MIB2_STATS_INC(mib2.ipinunknownprotos);
}
}
/* @todo: this is not really necessary... */
ip_data.current_netif = NULL;
ip_data.current_input_netif = NULL;
ip_data.current_ip4_header = NULL;
ip_data.current_ip_header_tot_len = 0;
ip4_addr_set_any(ip4_current_src_addr());
ip4_addr_set_any(ip4_current_dest_addr());
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.
* If the destination IP address is IP_HDRINCL, p is assumed to already
* include an IP header and p->payload points to it instead of the data.
*
* @param p the packet to send (p->payload points to the data, e.g. next
protocol header; if dest == IP_HDRINCL, p already includes an IP
header and p->payload points to that IP header)
* @param src the source IP address to send from (if src == IP_ADDR_ANY, the
* IP address of the netif used to send is used as source address)
* @param dest the destination IP address to send the packet to
* @param ttl the TTL value to be set in the IP header
* @param tos the TOS value to be set in the IP header
* @param proto the PROTOCOL to be set in the IP header
* @param netif the netif on which to send this packet
* @return ERR_OK if the packet was sent OK
* ERR_BUF if p doesn't have enough space for IP/LINK headers
* returns errors returned by netif->output
*
* @note ip_id: RFC791 "some host may be able to simply use
* unique identifiers independent of destination"
*/
err_t
ip4_output_if(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
u8_t ttl, u8_t tos,
u8_t proto, struct netif *netif)
{
#if IP_OPTIONS_SEND
return ip4_output_if_opt(p, src, dest, ttl, tos, proto, netif, NULL, 0);
}
/**
* Same as ip_output_if() but with the possibility to include IP options:
*
* @ param ip_options pointer to the IP options, copied into the IP header
* @ param optlen length of ip_options
*/
err_t
ip4_output_if_opt(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
u8_t ttl, u8_t tos, u8_t proto, struct netif *netif, void *ip_options,
u16_t optlen)
{
#endif /* IP_OPTIONS_SEND */
const ip4_addr_t *src_used = src;
if (dest != IP_HDRINCL) {
if (ip4_addr_isany(src)) {
src_used = netif_ip4_addr(netif);
}
}
#if IP_OPTIONS_SEND
return ip4_output_if_opt_src(p, src_used, dest, ttl, tos, proto, netif,
ip_options, optlen);
#else /* IP_OPTIONS_SEND */
return ip4_output_if_src(p, src_used, dest, ttl, tos, proto, netif);
#endif /* IP_OPTIONS_SEND */
}
/**
* Same as ip_output_if() but 'src' address is not replaced by netif address
* when it is 'any'.
*/
err_t
ip4_output_if_src(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
u8_t ttl, u8_t tos,
u8_t proto, struct netif *netif)
{
#if IP_OPTIONS_SEND
return ip4_output_if_opt_src(p, src, dest, ttl, tos, proto, netif, NULL, 0);
}
/**
* Same as ip_output_if_opt() but 'src' address is not replaced by netif address
* when it is 'any'.
*/
err_t
ip4_output_if_opt_src(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
u8_t ttl, u8_t tos, u8_t proto, struct netif *netif, void *ip_options,
u16_t optlen)
{
#endif /* IP_OPTIONS_SEND */
struct ip_hdr *iphdr;
ip4_addr_t dest_addr;
#if CHECKSUM_GEN_IP_INLINE
u32_t chk_sum = 0;
#endif /* CHECKSUM_GEN_IP_INLINE */
LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);
MIB2_STATS_INC(mib2.ipoutrequests);
/* Should the IP header be generated or is it already included in p? */
if (dest != IP_HDRINCL) {
u16_t ip_hlen = IP_HLEN;
#if IP_OPTIONS_SEND
u16_t optlen_aligned = 0;
if (optlen != 0) {
#if CHECKSUM_GEN_IP_INLINE
int i;
#endif /* CHECKSUM_GEN_IP_INLINE */
/* round up to a multiple of 4 */
optlen_aligned = ((optlen + 3) & ~3);
ip_hlen += optlen_aligned;
/* First write in the IP options */
if (pbuf_header(p, optlen_aligned)) {
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip4_output_if_opt: not enough room for IP options in pbuf\n"));
IP_STATS_INC(ip.err);
MIB2_STATS_INC(mib2.ipoutdiscards);
return ERR_BUF;
}
MEMCPY(p->payload, ip_options, optlen);
if (optlen < optlen_aligned) {
/* zero the remaining bytes */
memset(((char*)p->payload) + optlen, 0, optlen_aligned - optlen);
}
#if CHECKSUM_GEN_IP_INLINE
for (i = 0; i < optlen_aligned/2; i++) {
chk_sum += ((u16_t*)p->payload)[i];
}
#endif /* CHECKSUM_GEN_IP_INLINE */
}
#endif /* IP_OPTIONS_SEND */
/* generate IP header */
if (pbuf_header(p, IP_HLEN)) {
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip4_output: not enough room for IP header in pbuf\n"));
IP_STATS_INC(ip.err);
MIB2_STATS_INC(mib2.ipoutdiscards);
return ERR_BUF;
}
iphdr = (struct ip_hdr *)p->payload;
LWIP_ASSERT("check that first pbuf can hold struct ip_hdr",
(p->len >= sizeof(struct ip_hdr)));
IPH_TTL_SET(iphdr, ttl);
IPH_PROTO_SET(iphdr, proto);
#if CHECKSUM_GEN_IP_INLINE
chk_sum += LWIP_MAKE_U16(proto, ttl);
#endif /* CHECKSUM_GEN_IP_INLINE */
/* dest cannot be NULL here */
ip4_addr_copy(iphdr->dest, *dest);
#if CHECKSUM_GEN_IP_INLINE
chk_sum += ip4_addr_get_u32(&iphdr->dest) & 0xFFFF;
chk_sum += ip4_addr_get_u32(&iphdr->dest) >> 16;
#endif /* CHECKSUM_GEN_IP_INLINE */
IPH_VHL_SET(iphdr, 4, ip_hlen / 4);
IPH_TOS_SET(iphdr, tos);
#if CHECKSUM_GEN_IP_INLINE
chk_sum += LWIP_MAKE_U16(tos, iphdr->_v_hl);
#endif /* CHECKSUM_GEN_IP_INLINE */
IPH_LEN_SET(iphdr, htons(p->tot_len));
#if CHECKSUM_GEN_IP_INLINE
chk_sum += iphdr->_len;
#endif /* CHECKSUM_GEN_IP_INLINE */
IPH_OFFSET_SET(iphdr, 0);
IPH_ID_SET(iphdr, htons(ip_id));
#if CHECKSUM_GEN_IP_INLINE
chk_sum += iphdr->_id;
#endif /* CHECKSUM_GEN_IP_INLINE */
++ip_id;
if (src == NULL) {
ip4_addr_copy(iphdr->src, *IP4_ADDR_ANY);
} else {
/* src cannot be NULL here */
ip4_addr_copy(iphdr->src, *src);
}
#if CHECKSUM_GEN_IP_INLINE
chk_sum += ip4_addr_get_u32(&iphdr->src) & 0xFFFF;
chk_sum += ip4_addr_get_u32(&iphdr->src) >> 16;
chk_sum = (chk_sum >> 16) + (chk_sum & 0xFFFF);
chk_sum = (chk_sum >> 16) + chk_sum;
chk_sum = ~chk_sum;
IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_IP) {
iphdr->_chksum = (u16_t)chk_sum; /* network order */
}
#if LWIP_CHECKSUM_CTRL_PER_NETIF
else {
IPH_CHKSUM_SET(iphdr, 0);
}
#endif /* LWIP_CHECKSUM_CTRL_PER_NETIF*/
#else /* CHECKSUM_GEN_IP_INLINE */
IPH_CHKSUM_SET(iphdr, 0);
#if CHECKSUM_GEN_IP
IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_IP) {
IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, ip_hlen));
}
#endif /* CHECKSUM_GEN_IP */
#endif /* CHECKSUM_GEN_IP_INLINE */
} else {
/* IP header already included in p */
iphdr = (struct ip_hdr *)p->payload;
ip4_addr_copy(dest_addr, iphdr->dest);
dest = &dest_addr;
}
IP_STATS_INC(ip.xmit);
LWIP_DEBUGF(IP_DEBUG, ("ip4_output_if: %c%c%"U16_F"\n", netif->name[0], netif->name[1], netif->num));
ip4_debug_print(p);
#if ENABLE_LOOPBACK
if (ip4_addr_cmp(dest, netif_ip4_addr(netif))
#if !LWIP_HAVE_LOOPIF
|| ip4_addr_isloopback(dest)
#endif /* !LWIP_HAVE_LOOPIF */
) {
/* Packet to self, enqueue it for loopback */
LWIP_DEBUGF(IP_DEBUG, ("netif_loop_output()"));
return netif_loop_output(netif, p);
}
#if LWIP_MULTICAST_TX_OPTIONS
if ((p->flags & PBUF_FLAG_MCASTLOOP) != 0) {
netif_loop_output(netif, p);
}
#endif /* LWIP_MULTICAST_TX_OPTIONS */
#endif /* ENABLE_LOOPBACK */
#if IP_FRAG
/* don't fragment if interface has mtu set to 0 [loopif] */
if (netif->mtu && (p->tot_len > netif->mtu)) {
return ip4_frag(p, netif, dest);
}
#endif /* IP_FRAG */
LWIP_DEBUGF(IP_DEBUG, ("ip4_output_if: call netif->output()\n"));
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.
*
* @param p the packet to send (p->payload points to the data, e.g. next
protocol header; if dest == IP_HDRINCL, p already includes an IP
header and p->payload points to that IP header)
* @param src the source IP address to send from (if src == IP_ADDR_ANY, the
* IP address of the netif used to send is used as source address)
* @param dest the destination IP address to send the packet to
* @param ttl the TTL value to be set in the IP header
* @param tos the TOS value to be set in the IP header
* @param proto the PROTOCOL to be set in the IP header
*
* @return ERR_RTE if no route is found
* see ip_output_if() for more return values
*/
err_t
ip4_output(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
u8_t ttl, u8_t tos, u8_t proto)
{
struct netif *netif;
LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);
if ((netif = ip4_route_src(dest, src)) == NULL) {
LWIP_DEBUGF(IP_DEBUG, ("ip4_output: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest)));
IP_STATS_INC(ip.rterr);
return ERR_RTE;
}
return ip4_output_if(p, src, dest, ttl, tos, proto, netif);
}
#if LWIP_NETIF_HWADDRHINT
/** Like ip_output, but takes and addr_hint pointer that is passed on to netif->addr_hint
* before calling ip_output_if.
*
* @param p the packet to send (p->payload points to the data, e.g. next
protocol header; if dest == IP_HDRINCL, p already includes an IP
header and p->payload points to that IP header)
* @param src the source IP address to send from (if src == IP_ADDR_ANY, the
* IP address of the netif used to send is used as source address)
* @param dest the destination IP address to send the packet to
* @param ttl the TTL value to be set in the IP header
* @param tos the TOS value to be set in the IP header
* @param proto the PROTOCOL to be set in the IP header
* @param addr_hint address hint pointer set to netif->addr_hint before
* calling ip_output_if()
*
* @return ERR_RTE if no route is found
* see ip_output_if() for more return values
*/
err_t
ip4_output_hinted(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest,
u8_t ttl, u8_t tos, u8_t proto, u8_t *addr_hint)
{
struct netif *netif;
err_t err;
LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);
if ((netif = ip4_route_src(dest, src)) == NULL) {
LWIP_DEBUGF(IP_DEBUG, ("ip4_output: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
ip4_addr1_16(dest), ip4_addr2_16(dest), ip4_addr3_16(dest), ip4_addr4_16(dest)));
IP_STATS_INC(ip.rterr);
return ERR_RTE;
}
NETIF_SET_HWADDRHINT(netif, addr_hint);
err = ip4_output_if(p, src, dest, ttl, tos, proto, netif);
NETIF_SET_HWADDRHINT(netif, NULL);
return err;
}
#endif /* LWIP_NETIF_HWADDRHINT*/
#if IP_DEBUG
/* Print an IP header by using LWIP_DEBUGF
* @param p an IP packet, p->payload pointing to the IP header
*/
void
ip4_debug_print(struct pbuf *p)
{
struct ip_hdr *iphdr = (struct ip_hdr *)p->payload;
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_16(&iphdr->src),
ip4_addr2_16(&iphdr->src),
ip4_addr3_16(&iphdr->src),
ip4_addr4_16(&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_16(&iphdr->dest),
ip4_addr2_16(&iphdr->dest),
ip4_addr3_16(&iphdr->dest),
ip4_addr4_16(&iphdr->dest)));
LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
}
#endif /* IP_DEBUG */
#endif /* LWIP_IPV4 */
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