ip6_input.c

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/*
 *      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 1.11.2.3 2001/06/07 06:47:54 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.
 */

#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 <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>


int ipv6_rcv(struct sk_buff *skb, struct device *dev, struct packet_type *pt)
{
        struct ipv6hdr *hdr;
        u32             pkt_len;

        if (skb->pkt_type == PACKET_OTHERHOST)
                goto drop;

        ipv6_statistics.Ip6InReceives++;

        /* Store incoming device index. When the packet will
           be queued, we cannot refer to skb->dev anymore.
         */
        ((struct inet6_skb_parm *)skb->cb)->iif = dev->ifindex;

        hdr = skb->nh.ipv6h;

        if (skb->len < sizeof(struct ipv6hdr) || hdr->version != 6)
                goto err;

        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;
                skb_trim(skb, pkt_len + sizeof(struct ipv6hdr));
        }

        if (hdr->nexthdr == NEXTHDR_HOP) {
                skb->h.raw = (u8*)(hdr+1);
                if (!ipv6_parse_hopopts(skb, &hdr->nexthdr)) {
                        ipv6_statistics.Ip6InHdrErrors++;
                        return 0;
                }
        }

        if (skb->dst == NULL)
                ip6_route_input(skb);

        return skb->dst->input(skb);

truncated:
        ipv6_statistics.Ip6InTruncatedPkts++;
err:
        ipv6_statistics.Ip6InHdrErrors++;
drop:
        kfree_skb(skb);
        return 0;
}

/*
 *      0 - deliver
 *      1 - block
 */
static __inline__ int icmpv6_filter(struct sock *sk, struct sk_buff *skb)
{
        struct icmp6hdr *icmph;
        struct raw6_opt *opt;
        int bit_nr;

        opt = &sk->tp_pinfo.tp_raw;
        icmph = (struct icmp6hdr *) skb->h.raw;
        bit_nr = icmph->icmp6_type;
        if (bit_nr >= (8 * 32))
                return 0;
        return ((opt->filter.data[bit_nr >> 5] & (1 << bit_nr)) != 0);
}

/*
 *      demultiplex raw sockets.
 *      (should consider queueing the skb in the sock receive_queue
 *      without calling rawv6.c)
 */
static struct sock * ipv6_raw_deliver(struct sk_buff *skb,
                                      int nexthdr, unsigned long len)
{
        struct in6_addr *saddr;
        struct in6_addr *daddr;
        struct sock *sk, *sk2;
        __u8 hash;

        saddr = &skb->nh.ipv6h->saddr;
        daddr = saddr + 1;

        hash = nexthdr & (MAX_INET_PROTOS - 1);

        sk = raw_v6_htable[hash];

        /*
         *      The first socket found will be delivered after
         *      delivery to transport protocols.
         */

        if (sk == NULL)
                return NULL;

        sk = raw_v6_lookup(sk, nexthdr, daddr, saddr);

        if (sk) {
                sk2 = sk;

                while ((sk2 = raw_v6_lookup(sk2->next, nexthdr, daddr, saddr))) {
                        struct sk_buff *buff;

                        if (nexthdr == IPPROTO_ICMPV6 &&
                            icmpv6_filter(sk2, skb))
                                continue;

                        buff = skb_clone(skb, GFP_ATOMIC);
                        if (buff)
                                rawv6_rcv(sk2, buff, len);
                }
        }

        if (sk && nexthdr == IPPROTO_ICMPV6 && icmpv6_filter(sk, skb))
                sk = NULL;

        return sk;
}

/*
 *      Deliver the packet to the host
 */

int ip6_input(struct sk_buff *skb)
{
        struct ipv6hdr *hdr = skb->nh.ipv6h;
        struct inet6_protocol *ipprot;
        struct sock *raw_sk;
        __u8 *nhptr;
        int nexthdr;
        int found = 0;
        u8 hash;
        int len;
        
        skb->h.raw = skb->nh.raw + sizeof(struct ipv6hdr);

        /*
         *      Parse extension headers
         */

        nexthdr = hdr->nexthdr;
        nhptr = &hdr->nexthdr;

        /* Skip  hop-by-hop options, they are already parsed. */
        if (nexthdr == NEXTHDR_HOP) {
                nhptr = (u8*)(hdr+1);
                nexthdr = *nhptr;
                skb->h.raw += (nhptr[1]+1)<<3;
        }

        /* This check is sort of optimization.
           It would be stupid to detect for optional headers,
           which are missing with probability of 200%
         */
        if (nexthdr != IPPROTO_TCP && nexthdr != IPPROTO_UDP) {
                nhptr = ipv6_parse_exthdrs(&skb, nhptr);
                if (nhptr == NULL)
                        return 0;
                nexthdr = *nhptr;
                hdr = skb->nh.ipv6h;
        }
        len = skb->tail - skb->h.raw;

        raw_sk = ipv6_raw_deliver(skb, nexthdr, len);

        hash = nexthdr & (MAX_INET_PROTOS - 1);
        for (ipprot = (struct inet6_protocol *) inet6_protos[hash]; 
             ipprot != NULL; 
             ipprot = (struct inet6_protocol *) ipprot->next) {
                struct sk_buff *buff = skb;

                if (ipprot->protocol != nexthdr)
                        continue;

                if (ipprot->copy || raw_sk)
                        buff = skb_clone(skb, GFP_ATOMIC);
                /* buff == NULL ?????? */
                ipprot->handler(buff, len);
                found = 1;
        }

        if (raw_sk) {
                rawv6_rcv(raw_sk, skb, len);
                found = 1;
        }

        /*
         *      not found: send ICMP parameter problem back
         */
        if (!found) {
                ipv6_statistics.Ip6InUnknownProtos++;
                icmpv6_param_prob(skb, ICMPV6_UNK_NEXTHDR, nhptr);
        }

        return 0;
}

int ip6_mc_input(struct sk_buff *skb)
{
        struct ipv6hdr *hdr;    
        int deliver = 0;
        int discard = 1;

        ipv6_statistics.Ip6InMcastPkts++;

        hdr = skb->nh.ipv6h;
        if (ipv6_chk_mcast_addr(skb->dev, &hdr->daddr))
                deliver = 1;

        /*
         *      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);
                        } else {
                                discard = 0;
                                skb2 = skb;
                        }

                        dst->output(skb2);
                }
        }
#endif

        if (deliver) {
                discard = 0;
                ip6_input(skb);
        }

        if (discard)
                kfree_skb(skb);

        return 0;
}

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