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devilutionX-lwip/src/core/ipv4/ip.c

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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"
#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/tcp_impl.h"
#include "lwip/snmp.h"
#include "lwip/dhcp.h"
#include "lwip/autoip.h"
#include "lwip/stats.h"
#include "arch/perf.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
#define LWIP_INLINE_IP_CHKSUM 1
#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
* 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(dst_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(dst_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 interface that provided the packet for the current callback
* invocation.
*/
struct netif *current_netif;
/**
* Header of the input packet currently being processed.
*/
const struct ip_hdr *current_header;
/** Source IP address of current_header */
ip_addr_t current_iphdr_src;
/** Destination IP address of current_header */
ip_addr_t current_iphdr_dest;
/** The IP header ID of the next outgoing IP packet */
static u16_t ip_id;
/**
* 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 *
ip_route(ip_addr_t *dest)
{
struct netif *netif;
/* iterate through netifs */
for(netif = netif_list; netif != NULL; netif = netif->next) {
/* network mask matches? */
if (netif_is_up(netif)) {
if (ip_addr_netcmp(dest, &(netif->ip_addr), &(netif->netmask))) {
/* return netif on which to forward IP packet */
return netif;
}
}
}
if ((netif_default == NULL) || (!netif_is_up(netif_default))) {
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip_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);
snmp_inc_ipoutnoroutes();
return NULL;
}
/* 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.
*
* @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
ip_forward(struct pbuf *p, struct ip_hdr *iphdr, struct netif *inp)
{
struct netif *netif;
PERF_START;
/* RFC3927 2.7: do not forward link-local addresses */
if (ip_addr_islinklocal(&current_iphdr_dest)) {
LWIP_DEBUGF(IP_DEBUG, ("ip_forward: not forwarding LLA %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
ip4_addr1_16(&current_iphdr_dest), ip4_addr2_16(&current_iphdr_dest),
ip4_addr3_16(&current_iphdr_dest), ip4_addr4_16(&current_iphdr_dest)));
goto return_noroute;
}
/* Find network interface where to forward this IP packet to. */
netif = ip_route(&current_iphdr_dest);
if (netif == NULL) {
LWIP_DEBUGF(IP_DEBUG, ("ip_forward: no forwarding route for %"U16_F".%"U16_F".%"U16_F".%"U16_F" found\n",
ip4_addr1_16(&current_iphdr_dest), ip4_addr2_16(&current_iphdr_dest),
ip4_addr3_16(&current_iphdr_dest), ip4_addr4_16(&current_iphdr_dest)));
goto return_noroute;
}
/* 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"));
goto return_noroute;
}
/* decrement TTL */
IPH_TTL_SET(iphdr, IPH_TTL(iphdr) - 1);
/* send ICMP if TTL == 0 */
if (IPH_TTL(iphdr) == 0) {
snmp_inc_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(0xffff - 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, ("ip_forward: forwarding packet to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
ip4_addr1_16(&current_iphdr_dest), ip4_addr2_16(&current_iphdr_dest),
ip4_addr3_16(&current_iphdr_dest), ip4_addr4_16(&current_iphdr_dest)));
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, &current_iphdr_dest);
return;
return_noroute:
snmp_inc_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
ip_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
int check_ip_src=1;
#endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING */
IP_STATS_INC(ip.recv);
snmp_inc_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)));
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 */
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));
/* 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);
snmp_inc_ipindiscards();
return ERR_OK;
}
/* verify checksum */
#if 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)));
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, iphdr_len);
/* copy IP addresses to aligned ip_addr_t */
ip_addr_copy(current_iphdr_dest, iphdr->dest);
ip_addr_copy(current_iphdr_src, iphdr->src);
/* match packet against an interface, i.e. is this packet for us? */
#if LWIP_IGMP
if (ip_addr_ismulticast(&current_iphdr_dest)) {
if ((inp->flags & NETIF_FLAG_IGMP) && (igmp_lookfor_group(inp, &current_iphdr_dest))) {
netif = inp;
} else {
netif = NULL;
}
} else
#endif /* LWIP_IGMP */
{
/* 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->ip_addr),
ip4_addr_get_u32(&iphdr->dest) & ip4_addr_get_u32(&netif->netmask),
ip4_addr_get_u32(&netif->ip_addr) & ip4_addr_get_u32(&netif->netmask),
ip4_addr_get_u32(&iphdr->dest) & ~ip4_addr_get_u32(&netif->netmask)));
/* 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(&current_iphdr_dest, &(netif->ip_addr)) ||
/* or broadcast on this interface network address? */
ip_addr_isbroadcast(&current_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_AUTOIP
/* connections to link-local addresses must persist after changing
the netif's address (RFC3927 ch. 1.9) */
if ((netif->autoip != NULL) &&
ip_addr_cmp(&current_iphdr_dest, &(netif->autoip->llipaddr))) {
LWIP_DEBUGF(IP_DEBUG, ("ip_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, ("ip_input: UDP packet to DHCP client port %"U16_F"\n",
ntohs(udphdr->dest)));
u16_t dst_port = udphdr->dest;
if (IP_ACCEPT_LINK_LAYER_ADDRESSED_PORT(dst_port)) {
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE, ("ip_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 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) */
if (check_ip_src && !ip_addr_isany(&current_iphdr_src))
#endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING */
{ if ((ip_addr_isbroadcast(&current_iphdr_src, inp)) ||
(ip_addr_ismulticast(&current_iphdr_src))) {
/* packet source is not valid */
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("ip_input: packet source is not valid.\n"));
/* free (drop) packet pbufs */
pbuf_free(p);
IP_STATS_INC(ip.drop);
snmp_inc_ipinaddrerrors();
snmp_inc_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, ("ip_input: packet not for us.\n"));
#if IP_FORWARD
/* non-broadcast packet? */
if (!ip_addr_isbroadcast(&current_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) & 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 ip_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 = ip_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 */
snmp_inc_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 */
snmp_inc_ipinunknownprotos();
return ERR_OK;
}
#endif /* IP_OPTIONS_ALLOWED == 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));
current_netif = inp;
current_header = iphdr;
#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:
#if LWIP_UDPLITE
case IP_PROTO_UDPLITE:
#endif /* LWIP_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 */
#if LWIP_ICMP
case IP_PROTO_ICMP:
snmp_inc_ipindelivers();
icmp_input(p, inp);
break;
#endif /* LWIP_ICMP */
#if LWIP_IGMP
case IP_PROTO_IGMP:
igmp_input(p, inp, &current_iphdr_dest);
break;
#endif /* LWIP_IGMP */
default:
#if LWIP_ICMP
/* send ICMP destination protocol unreachable unless is was a broadcast */
if (!ip_addr_isbroadcast(&current_iphdr_dest, inp) &&
!ip_addr_ismulticast(&current_iphdr_dest)) {
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);
snmp_inc_ipinunknownprotos();
}
}
current_netif = NULL;
current_header = NULL;
ip_addr_set_any(&current_iphdr_src);
ip_addr_set_any(&current_iphdr_dest);
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
ip_output_if(struct pbuf *p, ip_addr_t *src, ip_addr_t *dest,
u8_t ttl, u8_t tos,
u8_t proto, struct netif *netif)
{
#if IP_OPTIONS_SEND
return ip_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 ip_output_if_opt(struct pbuf *p, ip_addr_t *src, ip_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;
ip_addr_t dest_addr;
#if CHECKSUM_GEN_IP_INLINE
u32_t chk_sum;
#endif /* CHECKSUM_GEN_IP_INLINE */
/* pbufs passed to IP must have a ref-count of 1 as their payload pointer
gets altered as the packet is passed down the stack */
LWIP_ASSERT("p->ref == 1", p->ref == 1);
snmp_inc_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) {
/* 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, ("ip_output_if_opt: not enough room for IP options in pbuf\n"));
IP_STATS_INC(ip.err);
snmp_inc_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);
}
}
#endif /* IP_OPTIONS_SEND */
/* generate IP header */
if (pbuf_header(p, IP_HLEN)) {
LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip_output: not enough room for IP header in pbuf\n"));
IP_STATS_INC(ip.err);
snmp_inc_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 */
ip_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_VHLTOS_SET(iphdr, 4, ip_hlen / 4, tos);
#if CHECKSUM_GEN_IP_INLINE
chk_sum += iphdr->_v_hl_tos;
#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 (ip_addr_isany(src)) {
ip_addr_copy(iphdr->src, netif->ip_addr);
} else {
/* src cannot be NULL here */
ip_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;
iphdr->_chksum = chk_sum; /* network order */
#else /* CHECKSUM_GEN_IP_INLINE */
IPH_CHKSUM_SET(iphdr, 0);
#if CHECKSUM_GEN_IP
IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, ip_hlen));
#endif
#endif /* CHECKSUM_GEN_IP_INLINE */
} else {
/* IP header already included in p */
iphdr = (struct ip_hdr *)p->payload;
ip_addr_copy(dest_addr, iphdr->dest);
dest = &dest_addr;
}
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);
#if ENABLE_LOOPBACK
if (ip_addr_cmp(dest, &netif->ip_addr)) {
/* Packet to self, enqueue it for loopback */
LWIP_DEBUGF(IP_DEBUG, ("netif_loop_output()"));
return netif_loop_output(netif, p, dest);
}
#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 ip_frag(p, netif, dest);
}
#endif
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.
*
* @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
ip_output(struct pbuf *p, ip_addr_t *src, ip_addr_t *dest,
u8_t ttl, u8_t tos, u8_t proto)
{
struct netif *netif;
/* pbufs passed to IP must have a ref-count of 1 as their payload pointer
gets altered as the packet is passed down the stack */
LWIP_ASSERT("p->ref == 1", p->ref == 1);
if ((netif = ip_route(dest)) == NULL) {
LWIP_DEBUGF(IP_DEBUG, ("ip_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 ip_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
ip_output_hinted(struct pbuf *p, ip_addr_t *src, ip_addr_t *dest,
u8_t ttl, u8_t tos, u8_t proto, u8_t *addr_hint)
{
struct netif *netif;
err_t err;
/* pbufs passed to IP must have a ref-count of 1 as their payload pointer
gets altered as the packet is passed down the stack */
LWIP_ASSERT("p->ref == 1", p->ref == 1);
if ((netif = ip_route(dest)) == NULL) {
LWIP_DEBUGF(IP_DEBUG, ("ip_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->addr_hint = addr_hint;
err = ip_output_if(p, src, dest, ttl, tos, proto, netif);
netif->addr_hint = 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
ip_debug_print(struct pbuf *p)
{
struct ip_hdr *iphdr = (struct ip_hdr *)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_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 */