linux/net/ipv6/ip6_input.c
Masahide NAKAMURA a80ff03e05 [IPV6]: Allow to replace skbuff by TLV parser.
In receiving Mobile IPv6 home address option which is a TLV carried by
destination options header, kernel will try to mangle source adderss
of packet. Think of cloned skbuff it is required to replace it by the
parser just like routing header case.

This is a framework to achieve that to allow TLV parser to replace
inbound skbuff pointer.

Signed-off-by: Masahide NAKAMURA <nakam@linux-ipv6.org>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22 15:06:51 -07:00

263 lines
5.9 KiB
C

/*
* IPv6 input
* Linux INET6 implementation
*
* Authors:
* Pedro Roque <roque@di.fc.ul.pt>
* Ian P. Morris <I.P.Morris@soton.ac.uk>
*
* $Id: ip6_input.c,v 1.19 2000/12/13 18:31:50 davem Exp $
*
* Based in linux/net/ipv4/ip_input.c
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
/* Changes
*
* Mitsuru KANDA @USAGI and
* YOSHIFUJI Hideaki @USAGI: Remove ipv6_parse_exthdrs().
*/
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/sched.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/in6.h>
#include <linux/icmpv6.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv6.h>
#include <net/sock.h>
#include <net/snmp.h>
#include <net/ipv6.h>
#include <net/protocol.h>
#include <net/transp_v6.h>
#include <net/rawv6.h>
#include <net/ndisc.h>
#include <net/ip6_route.h>
#include <net/addrconf.h>
#include <net/xfrm.h>
inline int ip6_rcv_finish( struct sk_buff *skb)
{
if (skb->dst == NULL)
ip6_route_input(skb);
return dst_input(skb);
}
int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
{
struct ipv6hdr *hdr;
u32 pkt_len;
if (skb->pkt_type == PACKET_OTHERHOST)
goto drop;
IP6_INC_STATS_BH(IPSTATS_MIB_INRECEIVES);
if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
IP6_INC_STATS_BH(IPSTATS_MIB_INDISCARDS);
goto out;
}
memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
/*
* Store incoming device index. When the packet will
* be queued, we cannot refer to skb->dev anymore.
*
* BTW, when we send a packet for our own local address on a
* non-loopback interface (e.g. ethX), it is being delivered
* via the loopback interface (lo) here; skb->dev = &loopback_dev.
* It, however, should be considered as if it is being
* arrived via the sending interface (ethX), because of the
* nature of scoping architecture. --yoshfuji
*/
IP6CB(skb)->iif = skb->dst ? ((struct rt6_info *)skb->dst)->rt6i_idev->dev->ifindex : dev->ifindex;
if (unlikely(!pskb_may_pull(skb, sizeof(*hdr))))
goto err;
hdr = skb->nh.ipv6h;
if (hdr->version != 6)
goto err;
skb->h.raw = (u8 *)(hdr + 1);
IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
pkt_len = ntohs(hdr->payload_len);
/* pkt_len may be zero if Jumbo payload option is present */
if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
if (pkt_len + sizeof(struct ipv6hdr) > skb->len)
goto truncated;
if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
goto drop;
}
hdr = skb->nh.ipv6h;
}
if (hdr->nexthdr == NEXTHDR_HOP) {
if (ipv6_parse_hopopts(&skb) < 0) {
IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
return 0;
}
}
return NF_HOOK(PF_INET6,NF_IP6_PRE_ROUTING, skb, dev, NULL, ip6_rcv_finish);
truncated:
IP6_INC_STATS_BH(IPSTATS_MIB_INTRUNCATEDPKTS);
err:
IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
drop:
kfree_skb(skb);
out:
return 0;
}
/*
* Deliver the packet to the host
*/
static inline int ip6_input_finish(struct sk_buff *skb)
{
struct inet6_protocol *ipprot;
struct sock *raw_sk;
unsigned int nhoff;
int nexthdr;
u8 hash;
/*
* Parse extension headers
*/
rcu_read_lock();
resubmit:
if (!pskb_pull(skb, skb->h.raw - skb->data))
goto discard;
nhoff = IP6CB(skb)->nhoff;
nexthdr = skb->nh.raw[nhoff];
raw_sk = sk_head(&raw_v6_htable[nexthdr & (MAX_INET_PROTOS - 1)]);
if (raw_sk && !ipv6_raw_deliver(skb, nexthdr))
raw_sk = NULL;
hash = nexthdr & (MAX_INET_PROTOS - 1);
if ((ipprot = rcu_dereference(inet6_protos[hash])) != NULL) {
int ret;
if (ipprot->flags & INET6_PROTO_FINAL) {
struct ipv6hdr *hdr;
/* Free reference early: we don't need it any more,
and it may hold ip_conntrack module loaded
indefinitely. */
nf_reset(skb);
skb_postpull_rcsum(skb, skb->nh.raw,
skb->h.raw - skb->nh.raw);
hdr = skb->nh.ipv6h;
if (ipv6_addr_is_multicast(&hdr->daddr) &&
!ipv6_chk_mcast_addr(skb->dev, &hdr->daddr,
&hdr->saddr) &&
!ipv6_is_mld(skb, nexthdr))
goto discard;
}
if (!(ipprot->flags & INET6_PROTO_NOPOLICY) &&
!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
goto discard;
ret = ipprot->handler(&skb);
if (ret > 0)
goto resubmit;
else if (ret == 0)
IP6_INC_STATS_BH(IPSTATS_MIB_INDELIVERS);
} else {
if (!raw_sk) {
if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
IP6_INC_STATS_BH(IPSTATS_MIB_INUNKNOWNPROTOS);
icmpv6_send(skb, ICMPV6_PARAMPROB,
ICMPV6_UNK_NEXTHDR, nhoff,
skb->dev);
}
} else
IP6_INC_STATS_BH(IPSTATS_MIB_INDELIVERS);
kfree_skb(skb);
}
rcu_read_unlock();
return 0;
discard:
IP6_INC_STATS_BH(IPSTATS_MIB_INDISCARDS);
rcu_read_unlock();
kfree_skb(skb);
return 0;
}
int ip6_input(struct sk_buff *skb)
{
return NF_HOOK(PF_INET6,NF_IP6_LOCAL_IN, skb, skb->dev, NULL, ip6_input_finish);
}
int ip6_mc_input(struct sk_buff *skb)
{
struct ipv6hdr *hdr;
int deliver;
IP6_INC_STATS_BH(IPSTATS_MIB_INMCASTPKTS);
hdr = skb->nh.ipv6h;
deliver = likely(!(skb->dev->flags & (IFF_PROMISC|IFF_ALLMULTI))) ||
ipv6_chk_mcast_addr(skb->dev, &hdr->daddr, NULL);
/*
* IPv6 multicast router mode isnt currently supported.
*/
#if 0
if (ipv6_config.multicast_route) {
int addr_type;
addr_type = ipv6_addr_type(&hdr->daddr);
if (!(addr_type & (IPV6_ADDR_LOOPBACK | IPV6_ADDR_LINKLOCAL))) {
struct sk_buff *skb2;
struct dst_entry *dst;
dst = skb->dst;
if (deliver) {
skb2 = skb_clone(skb, GFP_ATOMIC);
dst_output(skb2);
} else {
dst_output(skb);
return 0;
}
}
}
#endif
if (likely(deliver)) {
ip6_input(skb);
return 0;
}
/* discard */
kfree_skb(skb);
return 0;
}