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lwip/src/core/ipv6/ip6.c
David van Moolenbroek 0b9d7a386c ip6: improve source address selection 
The introduction of address lifetimes also means that lwIP correctly
supports transitions between PREFERRED and DEPRECATED address states,
and that means that the source address selection must be changed to
take this into account. Adding this feature to the previous algorithm
would have resulted in a mess, so this patch rewrites the algorithm to
stay close to the rules described in RFC 6724 (formerly 3484) Sec. 5.
This yields the following changes:

- Rule 2 ("prefer appropriate scope") is now fully implemented, most
  importantly allowing larger-scope addresses to be picked if no
  smaller-scope addresses are available (e.g., a global address may
  now be used to connect to a unique-local address);
- Rule 3 ("avoid deprecated addresses") is now also fully implemented;
- unknown-scope addresses are also supported, with lowest priority;
- the link between the prescribed rules and the actual algorithm is
  made much more explicit, hopefully allowing future improvements to
  be made more easily.

For reasons explained in comments, one previous deviation from the RFC
on Rule 2 is retained for now.
2017-01-11 07:54:14 +01:00

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/**
* @file
*
* IPv6 layer.
*/
/*
* Copyright (c) 2010 Inico Technologies Ltd.
* 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: Ivan Delamer <delamer@inicotech.com>
*
*
* Please coordinate changes and requests with Ivan Delamer
* <delamer@inicotech.com>
*/
#include "lwip/opt.h"
#if LWIP_IPV6 /* don't build if not configured for use in lwipopts.h */
#include "lwip/def.h"
#include "lwip/mem.h"
#include "lwip/netif.h"
#include "lwip/ip.h"
#include "lwip/ip6.h"
#include "lwip/ip6_addr.h"
#include "lwip/ip6_frag.h"
#include "lwip/icmp6.h"
#include "lwip/raw.h"
#include "lwip/udp.h"
#include "lwip/priv/tcp_priv.h"
#include "lwip/dhcp6.h"
#include "lwip/nd6.h"
#include "lwip/mld6.h"
#include "lwip/debug.h"
#include "lwip/stats.h"
/**
* Finds the appropriate network interface for a given IPv6 address. It tries to select
* a netif following a sequence of heuristics:
* 1) if there is only 1 netif, return it
* 2) if the destination is a link-local address, try to match the src address to a netif.
* this is a tricky case because with multiple netifs, link-local addresses only have
* meaning within a particular subnet/link.
* 3) tries to match the destination subnet to a configured address
* 4) tries to find a router-announced route
* 5) tries to match the source address to the netif
* 6) returns the default netif, if configured
*
* @param src the source IPv6 address, if known
* @param dest the destination IPv6 address for which to find the route
* @return the netif on which to send to reach dest
*/
struct netif *
ip6_route(const ip6_addr_t *src, const ip6_addr_t *dest)
{
struct netif *netif;
s8_t i;
/* If single netif configuration, fast return. */
if ((netif_list != NULL) && (netif_list->next == NULL)) {
if (!netif_is_up(netif_list) || !netif_is_link_up(netif_list)) {
return NULL;
}
return netif_list;
}
/* Special processing for link-local addresses. */
if (ip6_addr_islinklocal(dest)) {
if (ip6_addr_isany(src)) {
/* Use default netif, if Up. */
if (netif_default == NULL || !netif_is_up(netif_default) ||
!netif_is_link_up(netif_default)) {
return NULL;
}
return netif_default;
}
/* Try to find the netif for the source address, checking that link is up. */
for (netif = netif_list; netif != NULL; netif = netif->next) {
if (!netif_is_up(netif) || !netif_is_link_up(netif)) {
continue;
}
for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) &&
ip6_addr_cmp(src, netif_ip6_addr(netif, i))) {
return netif;
}
}
}
/* netif not found, use default netif, if up */
if (netif_default == NULL || !netif_is_up(netif_default) ||
!netif_is_link_up(netif_default)) {
return NULL;
}
return netif_default;
}
/* we come here for non-link-local addresses */
#ifdef LWIP_HOOK_IP6_ROUTE
netif = LWIP_HOOK_IP6_ROUTE(src, dest);
if (netif != NULL) {
return netif;
}
#endif
/* See if the destination subnet matches a configured address. In accordance
* with RFC 5942, dynamically configured addresses do not have an implied
* local subnet, and thus should be considered /128 assignments. However, as
* such, the destination address may still match a local address, and so we
* still need to check for exact matches here. By (lwIP) policy, statically
* configured addresses do always have an implied local /64 subnet. */
for (netif = netif_list; netif != NULL; netif = netif->next) {
if (!netif_is_up(netif) || !netif_is_link_up(netif)) {
continue;
}
for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) &&
ip6_addr_netcmp(dest, netif_ip6_addr(netif, i)) &&
(netif_ip6_addr_isstatic(netif, i) ||
ip6_addr_nethostcmp(dest, netif_ip6_addr(netif, i)))) {
return netif;
}
}
}
/* Get the netif for a suitable router-announced route. */
netif = nd6_find_route(dest);
if (netif != NULL) {
return netif;
}
/* try with the netif that matches the source address. */
if (!ip6_addr_isany(src)) {
for (netif = netif_list; netif != NULL; netif = netif->next) {
if (!netif_is_up(netif) || !netif_is_link_up(netif)) {
continue;
}
for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) &&
ip6_addr_cmp(src, netif_ip6_addr(netif, i))) {
return netif;
}
}
}
}
#if LWIP_NETIF_LOOPBACK && !LWIP_HAVE_LOOPIF
/* loopif is disabled, loopback traffic is passed through any netif */
if (ip6_addr_isloopback(dest)) {
/* don't check for link on loopback traffic */
if (netif_default != NULL && 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 */
/* no matching netif found, use default netif, if up */
if ((netif_default == NULL) || !netif_is_up(netif_default) || !netif_is_link_up(netif_default)) {
return NULL;
}
return netif_default;
}
/**
* @ingroup ip6
* Select the best IPv6 source address for a given destination IPv6 address.
*
* This implementation follows RFC 6724 Sec. 5 to the following extent:
* - Rules 1, 2, 3: fully implemented
* - Rules 4, 5, 5.5: not applicable
* - Rule 6: not implemented
* - Rule 7: not applicable
* - Rule 8: limited to "prefer /64 subnet match over non-match"
*
* For Rule 2, we deliberately deviate from RFC 6724 Sec. 3.1 by considering
* ULAs to be of smaller scope than global addresses, to avoid that a preferred
* ULA is picked over a deprecated global address when given a global address
* as destination, as that would likely result in broken two-way communication.
*
* As long as temporary addresses are not supported (as used in Rule 7), a
* proper implementation of Rule 8 would obviate the need to implement Rule 6.
*
* @param netif the netif on which to send a packet
* @param dest the destination we are trying to reach
* @return the most suitable source address to use, or NULL if no suitable
* source address is found
*/
const ip_addr_t *
ip6_select_source_address(struct netif *netif, const ip6_addr_t *dest)
{
const ip_addr_t *best_addr;
const ip6_addr_t *cand_addr;
s8_t dest_scope, cand_scope, best_scope;
u8_t i, cand_pref, best_pref, cand_bits, best_bits;
/* Start by determining the scope of the given destination address. These
* tests are hopefully (roughly) in order of likeliness to match. */
if (ip6_addr_isglobal(dest)) {
dest_scope = IP6_MULTICAST_SCOPE_GLOBAL;
} else if (ip6_addr_islinklocal(dest) || ip6_addr_isloopback(dest)) {
dest_scope = IP6_MULTICAST_SCOPE_LINK_LOCAL;
} else if (ip6_addr_isuniquelocal(dest)) {
dest_scope = IP6_MULTICAST_SCOPE_ORGANIZATION_LOCAL;
} else if (ip6_addr_ismulticast(dest)) {
dest_scope = ip6_addr_multicast_scope(dest);
} else if (ip6_addr_issitelocal(dest)) {
dest_scope = IP6_MULTICAST_SCOPE_SITE_LOCAL;
} else {
/* no match, consider scope global */
dest_scope = IP6_MULTICAST_SCOPE_GLOBAL;
}
best_addr = NULL;
for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
/* Consider only valid (= preferred and deprecated) addresses. */
if (!ip6_addr_isvalid(netif_ip6_addr_state(netif, i))) {
continue;
}
/* Determine the scope of this candidate address. Same ordering idea. */
cand_addr = netif_ip6_addr(netif, i);
if (ip6_addr_isglobal(cand_addr)) {
cand_scope = IP6_MULTICAST_SCOPE_GLOBAL;
} else if (ip6_addr_islinklocal(cand_addr)) {
cand_scope = IP6_MULTICAST_SCOPE_LINK_LOCAL;
} else if (ip6_addr_isuniquelocal(cand_addr)) {
cand_scope = IP6_MULTICAST_SCOPE_ORGANIZATION_LOCAL;
} else if (ip6_addr_issitelocal(cand_addr)) {
cand_scope = IP6_MULTICAST_SCOPE_SITE_LOCAL;
} else {
/* no match, treat as low-priority global scope */
cand_scope = IP6_MULTICAST_SCOPE_RESERVEDF;
}
cand_pref = ip6_addr_ispreferred(netif_ip6_addr_state(netif, i));
/* @todo compute the actual common bits, for longest matching prefix. */
cand_bits = ip6_addr_netcmp(cand_addr, dest); /* just 1 or 0 for now */
if (cand_bits && ip6_addr_nethostcmp(cand_addr, dest)) {
return netif_ip_addr6(netif, i); /* Rule 1 */
}
if ((best_addr == NULL) || /* no alternative yet */
((cand_scope < best_scope) && (cand_scope >= dest_scope)) ||
((cand_scope > best_scope) && (best_scope < dest_scope)) || /* Rule 2 */
((cand_scope == best_scope) && ((cand_pref > best_pref) || /* Rule 3 */
((cand_pref == best_pref) && (cand_bits > best_bits))))) { /* Rule 8 */
/* We found a new "winning" candidate. */
best_addr = netif_ip_addr6(netif, i);
best_scope = cand_scope;
best_pref = cand_pref;
best_bits = cand_bits;
}
}
return best_addr; /* may be NULL */
}
#if LWIP_IPV6_FORWARD
/**
* Forwards an IPv6 packet. It finds an appropriate route for the
* packet, decrements the HL value of the packet, and outputs
* the packet on the appropriate interface.
*
* @param p the packet to forward (p->payload points to IP header)
* @param iphdr the IPv6 header of the input packet
* @param inp the netif on which this packet was received
*/
static void
ip6_forward(struct pbuf *p, struct ip6_hdr *iphdr, struct netif *inp)
{
struct netif *netif;
/* do not forward link-local or loopback addresses */
if (ip6_addr_islinklocal(ip6_current_dest_addr()) ||
ip6_addr_isloopback(ip6_current_dest_addr())) {
LWIP_DEBUGF(IP6_DEBUG, ("ip6_forward: not forwarding link-local address.\n"));
IP6_STATS_INC(ip6.rterr);
IP6_STATS_INC(ip6.drop);
return;
}
/* Find network interface where to forward this IP packet to. */
netif = ip6_route(IP6_ADDR_ANY6, ip6_current_dest_addr());
if (netif == NULL) {
LWIP_DEBUGF(IP6_DEBUG, ("ip6_forward: no route for %"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F"\n",
IP6_ADDR_BLOCK1(ip6_current_dest_addr()),
IP6_ADDR_BLOCK2(ip6_current_dest_addr()),
IP6_ADDR_BLOCK3(ip6_current_dest_addr()),
IP6_ADDR_BLOCK4(ip6_current_dest_addr()),
IP6_ADDR_BLOCK5(ip6_current_dest_addr()),
IP6_ADDR_BLOCK6(ip6_current_dest_addr()),
IP6_ADDR_BLOCK7(ip6_current_dest_addr()),
IP6_ADDR_BLOCK8(ip6_current_dest_addr())));
#if LWIP_ICMP6
/* Don't send ICMP messages in response to ICMP messages */
if (IP6H_NEXTH(iphdr) != IP6_NEXTH_ICMP6) {
icmp6_dest_unreach(p, ICMP6_DUR_NO_ROUTE);
}
#endif /* LWIP_ICMP6 */
IP6_STATS_INC(ip6.rterr);
IP6_STATS_INC(ip6.drop);
return;
}
/* Do not forward packets onto the same network interface on which
* they arrived. */
if (netif == inp) {
LWIP_DEBUGF(IP6_DEBUG, ("ip6_forward: not bouncing packets back on incoming interface.\n"));
IP6_STATS_INC(ip6.rterr);
IP6_STATS_INC(ip6.drop);
return;
}
/* decrement HL */
IP6H_HOPLIM_SET(iphdr, IP6H_HOPLIM(iphdr) - 1);
/* send ICMP6 if HL == 0 */
if (IP6H_HOPLIM(iphdr) == 0) {
#if LWIP_ICMP6
/* Don't send ICMP messages in response to ICMP messages */
if (IP6H_NEXTH(iphdr) != IP6_NEXTH_ICMP6) {
icmp6_time_exceeded(p, ICMP6_TE_HL);
}
#endif /* LWIP_ICMP6 */
IP6_STATS_INC(ip6.drop);
return;
}
if (netif->mtu && (p->tot_len > netif->mtu)) {
#if LWIP_ICMP6
/* Don't send ICMP messages in response to ICMP messages */
if (IP6H_NEXTH(iphdr) != IP6_NEXTH_ICMP6) {
icmp6_packet_too_big(p, netif->mtu);
}
#endif /* LWIP_ICMP6 */
IP6_STATS_INC(ip6.drop);
return;
}
LWIP_DEBUGF(IP6_DEBUG, ("ip6_forward: forwarding packet to %"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F"\n",
IP6_ADDR_BLOCK1(ip6_current_dest_addr()),
IP6_ADDR_BLOCK2(ip6_current_dest_addr()),
IP6_ADDR_BLOCK3(ip6_current_dest_addr()),
IP6_ADDR_BLOCK4(ip6_current_dest_addr()),
IP6_ADDR_BLOCK5(ip6_current_dest_addr()),
IP6_ADDR_BLOCK6(ip6_current_dest_addr()),
IP6_ADDR_BLOCK7(ip6_current_dest_addr()),
IP6_ADDR_BLOCK8(ip6_current_dest_addr())));
/* transmit pbuf on chosen interface */
netif->output_ip6(netif, p, ip6_current_dest_addr());
IP6_STATS_INC(ip6.fw);
IP6_STATS_INC(ip6.xmit);
return;
}
#endif /* LWIP_IPV6_FORWARD */
/**
* This function is called by the network interface device driver when
* an IPv6 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 ip6_forward).
*
* Finally, the packet is sent to the upper layer protocol input function.
*
* @param p the received IPv6 packet (p->payload points to IPv6 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
ip6_input(struct pbuf *p, struct netif *inp)
{
struct ip6_hdr *ip6hdr;
struct netif *netif;
u8_t nexth;
u16_t hlen; /* the current header length */
u8_t i;
#if 0 /*IP_ACCEPT_LINK_LAYER_ADDRESSING*/
@todo
int check_ip_src=1;
#endif /* IP_ACCEPT_LINK_LAYER_ADDRESSING */
IP6_STATS_INC(ip6.recv);
/* identify the IP header */
ip6hdr = (struct ip6_hdr *)p->payload;
if (IP6H_V(ip6hdr) != 6) {
LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_LEVEL_WARNING, ("IPv6 packet dropped due to bad version number %"U32_F"\n",
IP6H_V(ip6hdr)));
pbuf_free(p);
IP6_STATS_INC(ip6.err);
IP6_STATS_INC(ip6.drop);
return ERR_OK;
}
#ifdef LWIP_HOOK_IP6_INPUT
if (LWIP_HOOK_IP6_INPUT(p, inp)) {
/* the packet has been eaten */
return ERR_OK;
}
#endif
/* header length exceeds first pbuf length, or ip length exceeds total pbuf length? */
if ((IP6_HLEN > p->len) || ((IP6H_PLEN(ip6hdr) + IP6_HLEN) > p->tot_len)) {
if (IP6_HLEN > p->len) {
LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
("IPv6 header (len %"U16_F") does not fit in first pbuf (len %"U16_F"), IP packet dropped.\n",
(u16_t)IP6_HLEN, p->len));
}
if ((IP6H_PLEN(ip6hdr) + IP6_HLEN) > p->tot_len) {
LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
("IPv6 (plen %"U16_F") is longer than pbuf (len %"U16_F"), IP packet dropped.\n",
(u16_t)(IP6H_PLEN(ip6hdr) + IP6_HLEN), p->tot_len));
}
/* free (drop) packet pbufs */
pbuf_free(p);
IP6_STATS_INC(ip6.lenerr);
IP6_STATS_INC(ip6.drop);
return ERR_OK;
}
/* 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, IP6_HLEN + IP6H_PLEN(ip6hdr));
/* copy IP addresses to aligned ip6_addr_t */
ip_addr_copy_from_ip6(ip_data.current_iphdr_dest, ip6hdr->dest);
ip_addr_copy_from_ip6(ip_data.current_iphdr_src, ip6hdr->src);
/* Don't accept virtual IPv6 mapped IPv4 addresses */
if (ip6_addr_isipv6mappedipv4(ip_2_ip6(&ip_data.current_iphdr_dest)) ||
ip6_addr_isipv6mappedipv4(ip_2_ip6(&ip_data.current_iphdr_src)) ) {
IP6_STATS_INC(ip6.err);
IP6_STATS_INC(ip6.drop);
return ERR_OK;
}
/* current header pointer. */
ip_data.current_ip6_header = ip6hdr;
/* In netif, used in case we need to send ICMPv6 packets back. */
ip_data.current_netif = inp;
ip_data.current_input_netif = inp;
/* match packet against an interface, i.e. is this packet for us? */
if (ip6_addr_ismulticast(ip6_current_dest_addr())) {
/* Always joined to multicast if-local and link-local all-nodes group. */
if (ip6_addr_isallnodes_iflocal(ip6_current_dest_addr()) ||
ip6_addr_isallnodes_linklocal(ip6_current_dest_addr())) {
netif = inp;
}
#if LWIP_IPV6_MLD
else if (mld6_lookfor_group(inp, ip6_current_dest_addr())) {
netif = inp;
}
#else /* LWIP_IPV6_MLD */
else if (ip6_addr_issolicitednode(ip6_current_dest_addr())) {
/* Filter solicited node packets when MLD is not enabled
* (for Neighbor discovery). */
netif = NULL;
for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
if (ip6_addr_isvalid(netif_ip6_addr_state(inp, i)) &&
ip6_addr_cmp_solicitednode(ip6_current_dest_addr(), netif_ip6_addr(inp, i))) {
netif = inp;
LWIP_DEBUGF(IP6_DEBUG, ("ip6_input: solicited node packet accepted on interface %c%c\n",
netif->name[0], netif->name[1]));
break;
}
}
}
#endif /* LWIP_IPV6_MLD */
else {
netif = NULL;
}
} 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 {
/* interface is up? */
if (netif_is_up(netif)) {
/* unicast to this interface address? address configured? */
for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) &&
ip6_addr_cmp(ip6_current_dest_addr(), netif_ip6_addr(netif, i))) {
/* exit outer loop */
goto netif_found;
}
}
}
if (first) {
if (ip6_addr_islinklocal(ip6_current_dest_addr())
#if !LWIP_NETIF_LOOPBACK || LWIP_HAVE_LOOPIF
|| ip6_addr_isloopback(ip6_current_dest_addr())
#endif /* !LWIP_NETIF_LOOPBACK || LWIP_HAVE_LOOPIF */
) {
/* Do not match link-local addresses to other netifs. The loopback
* address is to be considered link-local and packets to it should be
* dropped on other interfaces, as per RFC 4291 Sec. 2.5.3. This
* requirement cannot be implemented in the case that loopback
* traffic is sent across a non-loopback interface, however.
*/
netif = NULL;
break;
}
first = 0;
netif = netif_list;
} else {
netif = netif->next;
}
if (netif == inp) {
netif = netif->next;
}
} while (netif != NULL);
netif_found:
LWIP_DEBUGF(IP6_DEBUG, ("ip6_input: packet accepted on interface %c%c\n",
netif ? netif->name[0] : 'X', netif? netif->name[1] : 'X'));
}
/* "::" packet source address? (used in duplicate address detection) */
if (ip6_addr_isany(ip6_current_src_addr()) &&
(!ip6_addr_issolicitednode(ip6_current_dest_addr()))) {
/* packet source is not valid */
/* free (drop) packet pbufs */
LWIP_DEBUGF(IP6_DEBUG, ("ip6_input: packet with src ANY_ADDRESS dropped\n"));
pbuf_free(p);
IP6_STATS_INC(ip6.drop);
goto ip6_input_cleanup;
}
/* packet not for us? */
if (netif == NULL) {
/* packet not for us, route or discard */
LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_TRACE, ("ip6_input: packet not for us.\n"));
#if LWIP_IPV6_FORWARD
/* non-multicast packet? */
if (!ip6_addr_ismulticast(ip6_current_dest_addr())) {
/* try to forward IP packet on (other) interfaces */
ip6_forward(p, ip6hdr, inp);
}
#endif /* LWIP_IPV6_FORWARD */
pbuf_free(p);
goto ip6_input_cleanup;
}
/* current netif pointer. */
ip_data.current_netif = netif;
/* Save next header type. */
nexth = IP6H_NEXTH(ip6hdr);
/* Init header length. */
hlen = ip_data.current_ip_header_tot_len = IP6_HLEN;
/* Move to payload. */
pbuf_header(p, -IP6_HLEN);
/* Process known option extension headers, if present. */
while (nexth != IP6_NEXTH_NONE)
{
switch (nexth) {
case IP6_NEXTH_HOPBYHOP:
LWIP_DEBUGF(IP6_DEBUG, ("ip6_input: packet with Hop-by-Hop options header\n"));
/* Get next header type. */
nexth = *((u8_t *)p->payload);
/* Get the header length. */
hlen = 8 * (1 + *((u8_t *)p->payload + 1));
ip_data.current_ip_header_tot_len += hlen;
/* Skip over this header. */
if (hlen > p->len) {
LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
("IPv6 options header (hlen %"U16_F") does not fit in first pbuf (len %"U16_F"), IPv6 packet dropped.\n",
hlen, p->len));
/* free (drop) packet pbufs */
pbuf_free(p);
IP6_STATS_INC(ip6.lenerr);
IP6_STATS_INC(ip6.drop);
goto ip6_input_cleanup;
}
pbuf_header(p, -(s16_t)hlen);
break;
case IP6_NEXTH_DESTOPTS:
LWIP_DEBUGF(IP6_DEBUG, ("ip6_input: packet with Destination options header\n"));
/* Get next header type. */
nexth = *((u8_t *)p->payload);
/* Get the header length. */
hlen = 8 * (1 + *((u8_t *)p->payload + 1));
ip_data.current_ip_header_tot_len += hlen;
/* Skip over this header. */
if (hlen > p->len) {
LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
("IPv6 options header (hlen %"U16_F") does not fit in first pbuf (len %"U16_F"), IPv6 packet dropped.\n",
hlen, p->len));
/* free (drop) packet pbufs */
pbuf_free(p);
IP6_STATS_INC(ip6.lenerr);
IP6_STATS_INC(ip6.drop);
goto ip6_input_cleanup;
}
pbuf_header(p, -(s16_t)hlen);
break;
case IP6_NEXTH_ROUTING:
LWIP_DEBUGF(IP6_DEBUG, ("ip6_input: packet with Routing header\n"));
/* Get next header type. */
nexth = *((u8_t *)p->payload);
/* Get the header length. */
hlen = 8 * (1 + *((u8_t *)p->payload + 1));
ip_data.current_ip_header_tot_len += hlen;
/* Skip over this header. */
if (hlen > p->len) {
LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
("IPv6 options header (hlen %"U16_F") does not fit in first pbuf (len %"U16_F"), IPv6 packet dropped.\n",
hlen, p->len));
/* free (drop) packet pbufs */
pbuf_free(p);
IP6_STATS_INC(ip6.lenerr);
IP6_STATS_INC(ip6.drop);
goto ip6_input_cleanup;
}
pbuf_header(p, -(s16_t)hlen);
break;
case IP6_NEXTH_FRAGMENT:
{
struct ip6_frag_hdr *frag_hdr;
LWIP_DEBUGF(IP6_DEBUG, ("ip6_input: packet with Fragment header\n"));
frag_hdr = (struct ip6_frag_hdr *)p->payload;
/* Get next header type. */
nexth = frag_hdr->_nexth;
/* Fragment Header length. */
hlen = 8;
ip_data.current_ip_header_tot_len += hlen;
/* Make sure this header fits in current pbuf. */
if (hlen > p->len) {
LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
("IPv6 options header (hlen %"U16_F") does not fit in first pbuf (len %"U16_F"), IPv6 packet dropped.\n",
hlen, p->len));
/* free (drop) packet pbufs */
pbuf_free(p);
IP6_FRAG_STATS_INC(ip6_frag.lenerr);
IP6_FRAG_STATS_INC(ip6_frag.drop);
goto ip6_input_cleanup;
}
/* Offset == 0 and more_fragments == 0? */
if ((frag_hdr->_fragment_offset &
PP_HTONS(IP6_FRAG_OFFSET_MASK | IP6_FRAG_MORE_FLAG)) == 0) {
/* This is a 1-fragment packet, usually a packet that we have
* already reassembled. Skip this header anc continue. */
pbuf_header(p, -(s16_t)hlen);
} else {
#if LWIP_IPV6_REASS
/* reassemble the packet */
p = ip6_reass(p);
/* packet not fully reassembled yet? */
if (p == NULL) {
goto ip6_input_cleanup;
}
/* Returned p point to IPv6 header.
* Update all our variables and pointers and continue. */
ip6hdr = (struct ip6_hdr *)p->payload;
nexth = IP6H_NEXTH(ip6hdr);
hlen = ip_data.current_ip_header_tot_len = IP6_HLEN;
pbuf_header(p, -IP6_HLEN);
#else /* LWIP_IPV6_REASS */
/* free (drop) packet pbufs */
LWIP_DEBUGF(IP6_DEBUG, ("ip6_input: packet with Fragment header dropped (with LWIP_IPV6_REASS==0)\n"));
pbuf_free(p);
IP6_STATS_INC(ip6.opterr);
IP6_STATS_INC(ip6.drop);
goto ip6_input_cleanup;
#endif /* LWIP_IPV6_REASS */
}
break;
}
default:
goto options_done;
break;
}
}
options_done:
/* p points to IPv6 header again. */
pbuf_header_force(p, (s16_t)ip_data.current_ip_header_tot_len);
/* send to upper layers */
LWIP_DEBUGF(IP6_DEBUG, ("ip6_input: \n"));
ip6_debug_print(p);
LWIP_DEBUGF(IP6_DEBUG, ("ip6_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 (nexth) {
case IP6_NEXTH_NONE:
pbuf_free(p);
break;
#if LWIP_UDP
case IP6_NEXTH_UDP:
#if LWIP_UDPLITE
case IP6_NEXTH_UDPLITE:
#endif /* LWIP_UDPLITE */
/* Point to payload. */
pbuf_header(p, -(s16_t)ip_data.current_ip_header_tot_len);
udp_input(p, inp);
break;
#endif /* LWIP_UDP */
#if LWIP_TCP
case IP6_NEXTH_TCP:
/* Point to payload. */
pbuf_header(p, -(s16_t)ip_data.current_ip_header_tot_len);
tcp_input(p, inp);
break;
#endif /* LWIP_TCP */
#if LWIP_ICMP6
case IP6_NEXTH_ICMP6:
/* Point to payload. */
pbuf_header(p, -(s16_t)ip_data.current_ip_header_tot_len);
icmp6_input(p, inp);
break;
#endif /* LWIP_ICMP */
default:
#if LWIP_ICMP6
/* send ICMP parameter problem unless it was a multicast or ICMPv6 */
if ((!ip6_addr_ismulticast(ip6_current_dest_addr())) &&
(IP6H_NEXTH(ip6hdr) != IP6_NEXTH_ICMP6)) {
icmp6_param_problem(p, ICMP6_PP_HEADER, ip_data.current_ip_header_tot_len - hlen);
}
#endif /* LWIP_ICMP */
LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip6_input: Unsupported transport protocol %"U16_F"\n", (u16_t)IP6H_NEXTH(ip6hdr)));
pbuf_free(p);
IP6_STATS_INC(ip6.proterr);
IP6_STATS_INC(ip6.drop);
break;
}
}
ip6_input_cleanup:
ip_data.current_netif = NULL;
ip_data.current_input_netif = NULL;
ip_data.current_ip6_header = NULL;
ip_data.current_ip_header_tot_len = 0;
ip6_addr_set_zero(ip6_current_src_addr());
ip6_addr_set_zero(ip6_current_dest_addr());
return ERR_OK;
}
/**
* Sends an IPv6 packet on a network interface. This function constructs
* the IPv6 header. If the source IPv6 address is NULL, the IPv6 "ANY" address is
* used as source (usually during network startup). If the source IPv6 address it
* IP6_ADDR_ANY, the most appropriate IPv6 address of the outgoing network
* interface is filled in as source address. If the destination IPv6 address is
* LWIP_IP_HDRINCL, p is assumed to already include an IPv6 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 == LWIP_IP_HDRINCL, p already includes an
IPv6 header and p->payload points to that IPv6 header)
* @param src the source IPv6 address to send from (if src == IP6_ADDR_ANY, an
* IP address of the netif is selected and used as source address.
* if src == NULL, IP6_ADDR_ANY is used as source)
* @param dest the destination IPv6 address to send the packet to
* @param hl the Hop Limit value to be set in the IPv6 header
* @param tc the Traffic Class value to be set in the IPv6 header
* @param nexth the Next Header to be set in the IPv6 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 IPv6/LINK headers
* returns errors returned by netif->output
*/
err_t
ip6_output_if(struct pbuf *p, const ip6_addr_t *src, const ip6_addr_t *dest,
u8_t hl, u8_t tc,
u8_t nexth, struct netif *netif)
{
const ip6_addr_t *src_used = src;
if (dest != LWIP_IP_HDRINCL) {
if (src != NULL && ip6_addr_isany(src)) {
src = ip_2_ip6(ip6_select_source_address(netif, dest));
if ((src == NULL) || ip6_addr_isany(src)) {
/* No appropriate source address was found for this packet. */
LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip6_output: No suitable source address for packet.\n"));
IP6_STATS_INC(ip6.rterr);
return ERR_RTE;
}
}
}
return ip6_output_if_src(p, src_used, dest, hl, tc, nexth, netif);
}
/**
* Same as ip6_output_if() but 'src' address is not replaced by netif address
* when it is 'any'.
*/
err_t
ip6_output_if_src(struct pbuf *p, const ip6_addr_t *src, const ip6_addr_t *dest,
u8_t hl, u8_t tc,
u8_t nexth, struct netif *netif)
{
struct ip6_hdr *ip6hdr;
ip6_addr_t dest_addr;
LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);
/* Should the IPv6 header be generated or is it already included in p? */
if (dest != LWIP_IP_HDRINCL) {
/* generate IPv6 header */
if (pbuf_header(p, IP6_HLEN)) {
LWIP_DEBUGF(IP6_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip6_output: not enough room for IPv6 header in pbuf\n"));
IP6_STATS_INC(ip6.err);
return ERR_BUF;
}
ip6hdr = (struct ip6_hdr *)p->payload;
LWIP_ASSERT("check that first pbuf can hold struct ip6_hdr",
(p->len >= sizeof(struct ip6_hdr)));
IP6H_HOPLIM_SET(ip6hdr, hl);
IP6H_NEXTH_SET(ip6hdr, nexth);
/* dest cannot be NULL here */
ip6_addr_copy(ip6hdr->dest, *dest);
IP6H_VTCFL_SET(ip6hdr, 6, tc, 0);
IP6H_PLEN_SET(ip6hdr, p->tot_len - IP6_HLEN);
if (src == NULL) {
src = IP6_ADDR_ANY6;
}
/* src cannot be NULL here */
ip6_addr_copy(ip6hdr->src, *src);
} else {
/* IP header already included in p */
ip6hdr = (struct ip6_hdr *)p->payload;
ip6_addr_copy(dest_addr, ip6hdr->dest);
dest = &dest_addr;
}
IP6_STATS_INC(ip6.xmit);
LWIP_DEBUGF(IP6_DEBUG, ("ip6_output_if: %c%c%"U16_F"\n", netif->name[0], netif->name[1], (u16_t)netif->num));
ip6_debug_print(p);
#if ENABLE_LOOPBACK
{
int i;
#if !LWIP_HAVE_LOOPIF
if (ip6_addr_isloopback(dest)) {
return netif_loop_output(netif, p);
}
#endif /* !LWIP_HAVE_LOOPIF */
for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) &&
ip6_addr_cmp(dest, netif_ip6_addr(netif, i))) {
/* Packet to self, enqueue it for loopback */
LWIP_DEBUGF(IP6_DEBUG, ("netif_loop_output()\n"));
return netif_loop_output(netif, p);
}
}
}
#endif /* ENABLE_LOOPBACK */
#if LWIP_IPV6_FRAG
/* don't fragment if interface has mtu set to 0 [loopif] */
if (netif->mtu && (p->tot_len > nd6_get_destination_mtu(dest, netif))) {
return ip6_frag(p, netif, dest);
}
#endif /* LWIP_IPV6_FRAG */
LWIP_DEBUGF(IP6_DEBUG, ("netif->output_ip6()\n"));
return netif->output_ip6(netif, p, dest);
}
/**
* Simple interface to ip6_output_if. It finds the outgoing network
* interface and calls upon ip6_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 == LWIP_IP_HDRINCL, p already includes an
IPv6 header and p->payload points to that IPv6 header)
* @param src the source IPv6 address to send from (if src == IP6_ADDR_ANY, an
* IP address of the netif is selected and used as source address.
* if src == NULL, IP6_ADDR_ANY is used as source)
* @param dest the destination IPv6 address to send the packet to
* @param hl the Hop Limit value to be set in the IPv6 header
* @param tc the Traffic Class value to be set in the IPv6 header
* @param nexth the Next Header to be set in the IPv6 header
*
* @return ERR_RTE if no route is found
* see ip_output_if() for more return values
*/
err_t
ip6_output(struct pbuf *p, const ip6_addr_t *src, const ip6_addr_t *dest,
u8_t hl, u8_t tc, u8_t nexth)
{
struct netif *netif;
struct ip6_hdr *ip6hdr;
ip6_addr_t src_addr, dest_addr;
LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);
if (dest != LWIP_IP_HDRINCL) {
netif = ip6_route(src, dest);
} else {
/* IP header included in p, read addresses. */
ip6hdr = (struct ip6_hdr *)p->payload;
ip6_addr_copy(src_addr, ip6hdr->src);
ip6_addr_copy(dest_addr, ip6hdr->dest);
netif = ip6_route(&src_addr, &dest_addr);
}
if (netif == NULL) {
LWIP_DEBUGF(IP6_DEBUG, ("ip6_output: no route for %"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F"\n",
IP6_ADDR_BLOCK1(dest),
IP6_ADDR_BLOCK2(dest),
IP6_ADDR_BLOCK3(dest),
IP6_ADDR_BLOCK4(dest),
IP6_ADDR_BLOCK5(dest),
IP6_ADDR_BLOCK6(dest),
IP6_ADDR_BLOCK7(dest),
IP6_ADDR_BLOCK8(dest)));
IP6_STATS_INC(ip6.rterr);
return ERR_RTE;
}
return ip6_output_if(p, src, dest, hl, tc, nexth, netif);
}
#if LWIP_NETIF_HWADDRHINT
/** Like ip6_output, but takes and addr_hint pointer that is passed on to netif->addr_hint
* before calling ip6_output_if.
*
* @param p the packet to send (p->payload points to the data, e.g. next
protocol header; if dest == LWIP_IP_HDRINCL, p already includes an
IPv6 header and p->payload points to that IPv6 header)
* @param src the source IPv6 address to send from (if src == IP6_ADDR_ANY, an
* IP address of the netif is selected and used as source address.
* if src == NULL, IP6_ADDR_ANY is used as source)
* @param dest the destination IPv6 address to send the packet to
* @param hl the Hop Limit value to be set in the IPv6 header
* @param tc the Traffic Class value to be set in the IPv6 header
* @param nexth the Next Header to be set in the IPv6 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
ip6_output_hinted(struct pbuf *p, const ip6_addr_t *src, const ip6_addr_t *dest,
u8_t hl, u8_t tc, u8_t nexth, u8_t *addr_hint)
{
struct netif *netif;
struct ip6_hdr *ip6hdr;
ip6_addr_t src_addr, dest_addr;
err_t err;
LWIP_IP_CHECK_PBUF_REF_COUNT_FOR_TX(p);
if (dest != LWIP_IP_HDRINCL) {
netif = ip6_route(src, dest);
} else {
/* IP header included in p, read addresses. */
ip6hdr = (struct ip6_hdr *)p->payload;
ip6_addr_copy(src_addr, ip6hdr->src);
ip6_addr_copy(dest_addr, ip6hdr->dest);
netif = ip6_route(&src_addr, &dest_addr);
}
if (netif == NULL) {
LWIP_DEBUGF(IP6_DEBUG, ("ip6_output: no route for %"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F":%"X16_F"\n",
IP6_ADDR_BLOCK1(dest),
IP6_ADDR_BLOCK2(dest),
IP6_ADDR_BLOCK3(dest),
IP6_ADDR_BLOCK4(dest),
IP6_ADDR_BLOCK5(dest),
IP6_ADDR_BLOCK6(dest),
IP6_ADDR_BLOCK7(dest),
IP6_ADDR_BLOCK8(dest)));
IP6_STATS_INC(ip6.rterr);
return ERR_RTE;
}
NETIF_SET_HWADDRHINT(netif, addr_hint);
err = ip6_output_if(p, src, dest, hl, tc, nexth, netif);
NETIF_SET_HWADDRHINT(netif, NULL);
return err;
}
#endif /* LWIP_NETIF_HWADDRHINT*/
#if LWIP_IPV6_MLD
/**
* Add a hop-by-hop options header with a router alert option and padding.
*
* Used by MLD when sending a Multicast listener report/done message.
*
* @param p the packet to which we will prepend the options header
* @param nexth the next header protocol number (e.g. IP6_NEXTH_ICMP6)
* @param value the value of the router alert option data (e.g. IP6_ROUTER_ALERT_VALUE_MLD)
* @return ERR_OK if hop-by-hop header was added, ERR_* otherwise
*/
err_t
ip6_options_add_hbh_ra(struct pbuf *p, u8_t nexth, u8_t value)
{
struct ip6_hbh_hdr *hbh_hdr;
/* Move pointer to make room for hop-by-hop options header. */
if (pbuf_header(p, sizeof(struct ip6_hbh_hdr))) {
LWIP_DEBUGF(IP6_DEBUG, ("ip6_options: no space for options header\n"));
IP6_STATS_INC(ip6.err);
return ERR_BUF;
}
hbh_hdr = (struct ip6_hbh_hdr *)p->payload;
/* Set fields. */
hbh_hdr->_nexth = nexth;
hbh_hdr->_hlen = 0;
hbh_hdr->_ra_opt_type = IP6_ROUTER_ALERT_OPTION;
hbh_hdr->_ra_opt_dlen = 2;
hbh_hdr->_ra_opt_data = value;
hbh_hdr->_padn_opt_type = IP6_PADN_ALERT_OPTION;
hbh_hdr->_padn_opt_dlen = 0;
return ERR_OK;
}
#endif /* LWIP_IPV6_MLD */
#if IP6_DEBUG
/* Print an IPv6 header by using LWIP_DEBUGF
* @param p an IPv6 packet, p->payload pointing to the IPv6 header
*/
void
ip6_debug_print(struct pbuf *p)
{
struct ip6_hdr *ip6hdr = (struct ip6_hdr *)p->payload;
LWIP_DEBUGF(IP6_DEBUG, ("IPv6 header:\n"));
LWIP_DEBUGF(IP6_DEBUG, ("+-------------------------------+\n"));
LWIP_DEBUGF(IP6_DEBUG, ("| %2"U16_F" | %3"U16_F" | %7"U32_F" | (ver, class, flow)\n",
IP6H_V(ip6hdr),
IP6H_TC(ip6hdr),
IP6H_FL(ip6hdr)));
LWIP_DEBUGF(IP6_DEBUG, ("+-------------------------------+\n"));
LWIP_DEBUGF(IP6_DEBUG, ("| %5"U16_F" | %3"U16_F" | %3"U16_F" | (plen, nexth, hopl)\n",
IP6H_PLEN(ip6hdr),
IP6H_NEXTH(ip6hdr),
IP6H_HOPLIM(ip6hdr)));
LWIP_DEBUGF(IP6_DEBUG, ("+-------------------------------+\n"));
LWIP_DEBUGF(IP6_DEBUG, ("| %4"X32_F" | %4"X32_F" | %4"X32_F" | %4"X32_F" | (src)\n",
IP6_ADDR_BLOCK1(&(ip6hdr->src)),
IP6_ADDR_BLOCK2(&(ip6hdr->src)),
IP6_ADDR_BLOCK3(&(ip6hdr->src)),
IP6_ADDR_BLOCK4(&(ip6hdr->src))));
LWIP_DEBUGF(IP6_DEBUG, ("| %4"X32_F" | %4"X32_F" | %4"X32_F" | %4"X32_F" |\n",
IP6_ADDR_BLOCK5(&(ip6hdr->src)),
IP6_ADDR_BLOCK6(&(ip6hdr->src)),
IP6_ADDR_BLOCK7(&(ip6hdr->src)),
IP6_ADDR_BLOCK8(&(ip6hdr->src))));
LWIP_DEBUGF(IP6_DEBUG, ("+-------------------------------+\n"));
LWIP_DEBUGF(IP6_DEBUG, ("| %4"X32_F" | %4"X32_F" | %4"X32_F" | %4"X32_F" | (dest)\n",
IP6_ADDR_BLOCK1(&(ip6hdr->dest)),
IP6_ADDR_BLOCK2(&(ip6hdr->dest)),
IP6_ADDR_BLOCK3(&(ip6hdr->dest)),
IP6_ADDR_BLOCK4(&(ip6hdr->dest))));
LWIP_DEBUGF(IP6_DEBUG, ("| %4"X32_F" | %4"X32_F" | %4"X32_F" | %4"X32_F" |\n",
IP6_ADDR_BLOCK5(&(ip6hdr->dest)),
IP6_ADDR_BLOCK6(&(ip6hdr->dest)),
IP6_ADDR_BLOCK7(&(ip6hdr->dest)),
IP6_ADDR_BLOCK8(&(ip6hdr->dest))));
LWIP_DEBUGF(IP6_DEBUG, ("+-------------------------------+\n"));
}
#endif /* IP6_DEBUG */
#endif /* LWIP_IPV6 */
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