C++ NF_HOOK函数代码示例

static int ip6_finish_output2(struct sk_buff *skb)
{
	struct dst_entry *dst = skb_dst(skb);
	struct net_device *dev = dst->dev;
	struct neighbour *neigh;
	struct in6_addr *nexthop;
	int ret;

	skb->protocol = htons(ETH_P_IPV6);
	skb->dev = dev;

	if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) {
		struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));

		if (!(dev->flags & IFF_LOOPBACK) && sk_mc_loop(skb->sk) &&
		    ((mroute6_socket(dev_net(dev), skb) &&
		     !(IP6CB(skb)->flags & IP6SKB_FORWARDED)) ||
		     ipv6_chk_mcast_addr(dev, &ipv6_hdr(skb)->daddr,
					 &ipv6_hdr(skb)->saddr))) {
			struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);

			/* Do not check for IFF_ALLMULTI; multicast routing
			   is not supported in any case.
			 */
			if (newskb)
				NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING,
					newskb, NULL, newskb->dev,
					dev_loopback_xmit);

			if (ipv6_hdr(skb)->hop_limit == 0) {
				IP6_INC_STATS(dev_net(dev), idev,
					      IPSTATS_MIB_OUTDISCARDS);
				kfree_skb(skb);
				return 0;
			}
		}

		IP6_UPD_PO_STATS(dev_net(dev), idev, IPSTATS_MIB_OUTMCAST,
				skb->len);

		if (IPV6_ADDR_MC_SCOPE(&ipv6_hdr(skb)->daddr) <=
		    IPV6_ADDR_SCOPE_NODELOCAL &&
		    !(dev->flags & IFF_LOOPBACK)) {
			kfree_skb(skb);
			return 0;
		}
	}

	rcu_read_lock_bh();
	nexthop = rt6_nexthop((struct rt6_info *)dst);
	neigh = __ipv6_neigh_lookup_noref(dst->dev, nexthop);
	if (unlikely(!neigh))
		neigh = __neigh_create(&nd_tbl, nexthop, dst->dev, false);
	if (!IS_ERR(neigh)) {
		ret = dst_neigh_output(dst, neigh, skb);
		rcu_read_unlock_bh();
		return ret;
	}
	rcu_read_unlock_bh();

	IP6_INC_STATS(dev_net(dst->dev),
		      ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
	kfree_skb(skb);
	return -EINVAL;
}

/*
 * 	Main IP Receive routine.
 */
int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
{
	struct iphdr *iph;
	u32 len;

	/* When the interface is in promisc. mode, drop all the crap
	 * that it receives, do not try to analyse it.
	 */
	if (skb->pkt_type == PACKET_OTHERHOST)
		goto drop;

	IP_INC_STATS_BH(dev_net(dev), IPSTATS_MIB_INRECEIVES);

	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
		IP_INC_STATS_BH(dev_net(dev), IPSTATS_MIB_INDISCARDS);
		goto out;
	}

	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
		goto inhdr_error;

	iph = ip_hdr(skb);

	/*
	 *	RFC1122: 3.2.1.2 MUST silently discard any IP frame that fails the checksum.
	 *
	 *	Is the datagram acceptable?
	 *
	 *	1.	Length at least the size of an ip header
	 *	2.	Version of 4
	 *	3.	Checksums correctly. [Speed optimisation for later, skip loopback checksums]
	 *	4.	Doesn't have a bogus length
	 */

	if (iph->ihl < 5 || iph->version != 4)
		goto inhdr_error;

	if (!pskb_may_pull(skb, iph->ihl*4))
		goto inhdr_error;

	iph = ip_hdr(skb);

	if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
		goto inhdr_error;

	len = ntohs(iph->tot_len);
	if (skb->len < len) {
		IP_INC_STATS_BH(dev_net(dev), IPSTATS_MIB_INTRUNCATEDPKTS);
		goto drop;
	} else if (len < (iph->ihl*4))
		goto inhdr_error;

	/* Our transport medium may have padded the buffer out. Now we know it
	 * is IP we can trim to the true length of the frame.
	 * Note this now means skb->len holds ntohs(iph->tot_len).
	 */
	if (pskb_trim_rcsum(skb, len)) {
		IP_INC_STATS_BH(dev_net(dev), IPSTATS_MIB_INDISCARDS);
		goto drop;
	}

	/* Remove any debris in the socket control block */
	memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));

	/* Must drop socket now because of tproxy. */
	skb_orphan(skb);

	return NF_HOOK(PF_INET, NF_INET_PRE_ROUTING, skb, dev, NULL,
		       ip_rcv_finish);

inhdr_error:
	IP_INC_STATS_BH(dev_net(dev), IPSTATS_MIB_INHDRERRORS);
drop:
	kfree_skb(skb);
out:
	return NET_RX_DROP;
}

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;
	struct inet6_dev *idev;

	if (skb->pkt_type == PACKET_OTHERHOST) {
		kfree_skb(skb);
		return 0;
	}

	rcu_read_lock();

	idev = __in6_dev_get(skb->dev);

	IP6_INC_STATS_BH(idev, IPSTATS_MIB_INRECEIVES);

	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL || !idev || unlikely(idev->cnf.disable_ipv6)) {
		IP6_INC_STATS_BH(idev, IPSTATS_MIB_INDISCARDS);
		rcu_read_unlock();
//		goto out;
		kfree_skb(skb);
		return 0;
	}

	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 ? ip6_dst_idev(skb->dst)->dev->ifindex : dev->ifindex;

	if (unlikely(!pskb_may_pull(skb, sizeof(*hdr))))
		goto err;

	hdr = skb->nh.ipv6h;

	if (hdr->version != 6)
		goto err;

	/*
	 * RFC4291 2.5.3
	 * A packet received on an interface with a destination address
	 * of loopback must be dropped.
	 */
	if (!(dev->flags & IFF_LOOPBACK) && ipv6_addr_loopback(&hdr->daddr))
                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) {
			IP6_INC_STATS_BH(idev, IPSTATS_MIB_INTRUNCATEDPKTS);
			goto drop;
		}
		if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) {
			IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS);
			goto drop;
		}
		hdr = skb->nh.ipv6h;
	}

	if (hdr->nexthdr == NEXTHDR_HOP) {
		if (ipv6_parse_hopopts(&skb) < 0) {
			IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS);
			rcu_read_unlock();
			return 0;
		}
	}

	rcu_read_unlock();

	return NF_HOOK(PF_INET6,NF_IP6_PRE_ROUTING, skb, dev, NULL, ip6_rcv_finish);
err:
	IP6_INC_STATS_BH(idev, IPSTATS_MIB_INHDRERRORS);
drop:
	rcu_read_unlock();
	kfree_skb(skb);
//out:
	return 0;
}

int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
	     struct ipv6_txoptions *opt, int tclass)
{
	struct net *net = sock_net(sk);
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct in6_addr *first_hop = &fl6->daddr;
	struct dst_entry *dst = skb_dst(skb);
	struct ipv6hdr *hdr;
	u8  proto = fl6->flowi6_proto;
	int seg_len = skb->len;
	int hlimit = -1;
	u32 mtu;

	if (opt) {
		unsigned int head_room;

		/* First: exthdrs may take lots of space (~8K for now)
		   MAX_HEADER is not enough.
		 */
		head_room = opt->opt_nflen + opt->opt_flen;
		seg_len += head_room;
		head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev);

		if (skb_headroom(skb) < head_room) {
			struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room);
			if (skb2 == NULL) {
				IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
					      IPSTATS_MIB_OUTDISCARDS);
				kfree_skb(skb);
				return -ENOBUFS;
			}
			consume_skb(skb);
			skb = skb2;
			skb_set_owner_w(skb, sk);
		}
		if (opt->opt_flen)
			ipv6_push_frag_opts(skb, opt, &proto);
		if (opt->opt_nflen)
			ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop);
	}

	skb_push(skb, sizeof(struct ipv6hdr));
	skb_reset_network_header(skb);
	hdr = ipv6_hdr(skb);

	/*
	 *	Fill in the IPv6 header
	 */
	if (np)
		hlimit = np->hop_limit;
	if (hlimit < 0)
		hlimit = ip6_dst_hoplimit(dst);

	ip6_flow_hdr(hdr, tclass, fl6->flowlabel);

	hdr->payload_len = htons(seg_len);
	hdr->nexthdr = proto;
	hdr->hop_limit = hlimit;

	hdr->saddr = fl6->saddr;
	hdr->daddr = *first_hop;

	skb->priority = sk->sk_priority;
	skb->mark = sk->sk_mark;

	mtu = dst_mtu(dst);
	if ((skb->len <= mtu) || skb->local_df || skb_is_gso(skb)) {
		IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)),
			      IPSTATS_MIB_OUT, skb->len);
		return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL,
			       dst->dev, dst_output);
	}

	skb->dev = dst->dev;
	ipv6_local_error(sk, EMSGSIZE, fl6, mtu);
	IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_FRAGFAILS);
	kfree_skb(skb);
	return -EMSGSIZE;
}

/*
 * The transport must make sure that this is serialized against other
 * rx and conn reset on this specific conn.
 *
 * We currently assert that only one fragmented message will be sent
 * down a connection at a time.  This lets us reassemble in the conn
 * instead of per-flow which means that we don't have to go digging through
 * flows to tear down partial reassembly progress on conn failure and
 * we save flow lookup and locking for each frag arrival.  It does mean
 * that small messages will wait behind large ones.  Fragmenting at all
 * is only to reduce the memory consumption of pre-posted buffers.
 *
 * The caller passes in saddr and daddr instead of us getting it from the
 * conn.  This lets loopback, who only has one conn for both directions,
 * tell us which roles the addrs in the conn are playing for this message.
 */
void rds_recv_incoming(struct rds_connection *conn, __be32 saddr, __be32 daddr,
		       struct rds_incoming *inc, gfp_t gfp)
{
	struct sk_buff *skb;
	struct rds_sock *rs;
	struct sock *sk;
	struct rds_nf_hdr *dst, *org;
	int    ret;

	rdsdebug(KERN_ALERT "incoming:  conn %p, inc %p, %u.%u.%u.%u : %d -> %u.%u.%u.%u : %d\n",
		 conn, inc, NIPQUAD(saddr), inc->i_hdr.h_sport, NIPQUAD(daddr), inc->i_hdr.h_dport);

	/* initialize some globals */
	rs = NULL;
	sk = NULL;

	/* save off the original connection against which the request arrived */
	inc->i_oconn = conn;
	inc->i_skb   = NULL;

	/* lets find a socket to which this request belongs */
	rs = rds_find_bound(daddr, inc->i_hdr.h_dport);

	/* pass it on locally if there is no socket bound, or if netfilter is
	 * disabled for this socket */
	if (NULL == rs || !rs->rs_netfilter_enabled) {
		/* drop the reference if we had taken one */
		if (NULL != rs)
			rds_sock_put(rs);

		rds_recv_local(conn, saddr, daddr, inc, gfp);
		return;
	}

	/* otherwise pull out the socket */
	sk = rds_rs_to_sk(rs);

	/* create an skb with some additional space to store our rds_nf_hdr info */
	skb = alloc_skb(sizeof(struct rds_nf_hdr) * 2, gfp);
	if (NULL == skb) {
		/* if we have allocation problems, then we just need to depart */
		rdsdebug("failure to allocate space for inc %p, %u.%u.%u.%u -> %u.%d.%u.%u\n",
			 inc, NIPQUAD(saddr), NIPQUAD(daddr));
		rds_recv_local(conn, saddr, daddr, inc, gfp);
		return;
	}

	/* once we've allocated an skb, also store it in our structures */
	inc->i_skb = skb;

	/* now pull out the rds headers */
	dst = rds_nf_hdr_dst(skb);
	org = rds_nf_hdr_org(skb);

	/* now update our rds_nf_hdr for tracking locations of the request */
	dst->saddr = saddr;
	dst->daddr = daddr;
	dst->sport = inc->i_hdr.h_sport;
	dst->dport = inc->i_hdr.h_dport;
	dst->flags = 0;

	/* assign the appropriate protocol if any */
	if (NULL != sk) {
		dst->protocol = sk->sk_protocol;
		dst->sk = sk;
	} else {
		dst->protocol = 0;
		dst->sk = NULL;
	}

	/* cleanup any references taken */
	if (NULL != rs)
		rds_sock_put(rs);

	/* the original info is just a copy */
	memcpy(org, dst, sizeof(struct rds_nf_hdr));

	/* convert our local data structures in the message to a generalized skb form */
	if (conn->c_trans->inc_to_skb(inc, skb)) {
		rdsdebug("handing off to PRE_ROUTING hook\n");
		/* call down through the hook layers */
		ret = NF_HOOK(PF_RDS_HOOK, NF_RDS_PRE_ROUTING, skb, NULL, NULL, rds_recv_ok);
	}
	/* if we had a failure to convert, then just assuming to continue as local */
//.........这里部分代码省略.........

int dn_route_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
{
	struct dn_skb_cb *cb;
	unsigned char flags = 0;
	__u16 len = dn_ntohs(*(__le16 *)skb->data);
	struct dn_dev *dn = (struct dn_dev *)dev->dn_ptr;
	unsigned char padlen = 0;

	if (dn == NULL)
		goto dump_it;

	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
		goto out;

	if (!pskb_may_pull(skb, 3))
		goto dump_it;

	skb_pull(skb, 2);

	if (len > skb->len)
		goto dump_it;

	skb_trim(skb, len);

	flags = *skb->data;

	cb = DN_SKB_CB(skb);
	cb->stamp = jiffies;
	cb->iif = dev->ifindex;

	/*
	 * If we have padding, remove it.
	 */
	if (flags & DN_RT_F_PF) {
		padlen = flags & ~DN_RT_F_PF;
		if (!pskb_may_pull(skb, padlen + 1))
			goto dump_it;
		skb_pull(skb, padlen);
		flags = *skb->data;
	}

	skb->nh.raw = skb->data;

	/*
	 * Weed out future version DECnet
	 */
	if (flags & DN_RT_F_VER)
		goto dump_it;

	cb->rt_flags = flags;

	if (decnet_debug_level & 1)
		printk(KERN_DEBUG 
			"dn_route_rcv: got 0x%02x from %s [%d %d %d]\n",
			(int)flags, (dev) ? dev->name : "???", len, skb->len, 
			padlen);

        if (flags & DN_RT_PKT_CNTL) {
		if (unlikely(skb_is_nonlinear(skb)) &&
		    skb_linearize(skb, GFP_ATOMIC) != 0)
			goto dump_it;

                switch(flags & DN_RT_CNTL_MSK) {
        	        case DN_RT_PKT_INIT:
				dn_dev_init_pkt(skb);
				break;
                	case DN_RT_PKT_VERI:
				dn_dev_veri_pkt(skb);
				break;
		}

		if (dn->parms.state != DN_DEV_S_RU)
			goto dump_it;

		switch(flags & DN_RT_CNTL_MSK) {
                	case DN_RT_PKT_HELO:
				return NF_HOOK(PF_DECnet, NF_DN_HELLO, skb, skb->dev, NULL, dn_route_ptp_hello);

                	case DN_RT_PKT_L1RT:
                	case DN_RT_PKT_L2RT:
                                return NF_HOOK(PF_DECnet, NF_DN_ROUTE, skb, skb->dev, NULL, dn_route_discard);
                	case DN_RT_PKT_ERTH:
				return NF_HOOK(PF_DECnet, NF_DN_HELLO, skb, skb->dev, NULL, dn_neigh_router_hello);

                	case DN_RT_PKT_EEDH:
				return NF_HOOK(PF_DECnet, NF_DN_HELLO, skb, skb->dev, NULL, dn_neigh_endnode_hello);
                }
        } else {
		if (dn->parms.state != DN_DEV_S_RU)
			goto dump_it;

		skb_pull(skb, 1); /* Pull flags */

                switch(flags & DN_RT_PKT_MSK) {
                	case DN_RT_PKT_LONG:
                        	return dn_route_rx_long(skb);
                	case DN_RT_PKT_SHORT:
                        	return dn_route_rx_short(skb);
		}
        }
//.........这里部分代码省略.........

//.........这里部分代码省略.........
			goto drop;

		spin_lock(&x->lock);
		if (unlikely(x->km.state != XFRM_STATE_VALID))
			goto drop_unlock;

		if (xfrm_state_check_expire(x))
			goto drop_unlock;

		xfrm_vec[xfrm_nr].decap.decap_type = encap_type;
		if (x->type->input(x, &(xfrm_vec[xfrm_nr].decap), skb))
			goto drop_unlock;

		/* only the first xfrm gets the encap type */
		encap_type = 0;

		x->curlft.bytes += skb->len;
		x->curlft.packets++;

		spin_unlock(&x->lock);

		xfrm_vec[xfrm_nr++].xvec = x;

		iph = skb->nh.iph;

		if (x->props.mode) {
			if (iph->protocol != IPPROTO_IPIP)
				goto drop;
			if (!pskb_may_pull(skb, sizeof(struct iphdr)))
				goto drop;
			if (skb_cloned(skb) &&
			    pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
				goto drop;
			if (x->props.flags & XFRM_STATE_DECAP_DSCP)
				ipv4_copy_dscp(iph, skb->h.ipiph);
			if (!(x->props.flags & XFRM_STATE_NOECN))
				ipip_ecn_decapsulate(skb);
			skb->mac.raw = memmove(skb->data - skb->mac_len,
					       skb->mac.raw, skb->mac_len);
			skb->nh.raw = skb->data;
			memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
			decaps = 1;
			break;
		}

		if ((err = xfrm_parse_spi(skb, skb->nh.iph->protocol, &spi)) < 0)
			goto drop;

	} while (!err);

	/* Allocate new secpath or COW existing one. */

	if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
		struct sec_path *sp;
		sp = secpath_dup(skb->sp);
		if (!sp)
			goto drop;
		if (skb->sp)
			secpath_put(skb->sp);
		skb->sp = sp;
	}
	if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH)
		goto drop;

	memcpy(skb->sp->x+skb->sp->len, xfrm_vec, xfrm_nr*sizeof(struct sec_decap_state));
	skb->sp->len += xfrm_nr;

	nf_reset(skb);

	if (decaps) {
		if (!(skb->dev->flags&IFF_LOOPBACK)) {
			dst_release(skb->dst);
			skb->dst = NULL;
		}
		netif_rx(skb);
		return 0;
	} else {
#ifdef CONFIG_NETFILTER
		__skb_push(skb, skb->data - skb->nh.raw);
		skb->nh.iph->tot_len = htons(skb->len);
		ip_send_check(skb->nh.iph);

		NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL,
		        xfrm4_rcv_encap_finish);
		return 0;
#else
		return -skb->nh.iph->protocol;
#endif
	}

drop_unlock:
	spin_unlock(&x->lock);
	xfrm_state_put(x);
drop:
	while (--xfrm_nr >= 0)
		xfrm_state_put(xfrm_vec[xfrm_nr].xvec);

	kfree_skb(skb);
	return 0;
}

int dn_nsp_rx(struct sk_buff *skb)
{
	return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_IN,
		       &init_net, NULL, skb, skb->dev, NULL,
		       dn_nsp_rx_packet);
}

/* Paul: This seems to be unused dead code */
enum ipsec_xmit_value
ipsec_mast_send(struct ipsec_xmit_state*ixs)
{
	/* new route/dst cache code from James Morris */
	ixs->skb->dev = ixs->physdev;
	/*skb_orphan(ixs->skb);*/
	if((ixs->error = ip_route_output(&ixs->route,
				    ixs->skb->nh.iph->daddr,
				    ixs->pass ? 0 : ixs->skb->nh.iph->saddr,
				    RT_TOS(ixs->skb->nh.iph->tos),
				    ixs->physdev->ifindex /* rgb: should this be 0? */))) {
		ixs->stats->tx_errors++;
		KLIPS_PRINT(debug_mast & DB_MAST_XMIT,
			    "klips_debug:ipsec_mast_send: "
			    "ip_route_output failed with error code %d, dropped\n",
			    ixs->error);
		return IPSEC_XMIT_ROUTEERR;
	}
	if(ixs->dev == ixs->route->u.dst.dev) {
		ip_rt_put(ixs->route);
		/* This is recursion, drop it. */
		ixs->stats->tx_errors++;
		KLIPS_PRINT(debug_mast & DB_MAST_XMIT,
			    "klips_debug:ipsec_mast_send: "
			    "suspect recursion, dev=rt->u.dst.dev=%s, dropped\n",
			    ixs->dev->name);
		return IPSEC_XMIT_RECURSDETECT;
	}
	dst_release(skb_dst(ixs->skb));
	skb_dst_set(ixs->skb, &ixs->route->u.dst);
	ixs->stats->tx_bytes += ixs->skb->len;
	if(ixs->skb->len < ixs->skb->nh.raw - ixs->skb->data) {
		ixs->stats->tx_errors++;
		printk(KERN_WARNING
		       "klips_error:ipsec_mast_send: "
		       "tried to __skb_pull nh-data=%ld, %d available.  This should never happen, please report.\n",
		       (unsigned long)(ixs->skb->nh.raw - ixs->skb->data),
		       ixs->skb->len);
		return IPSEC_XMIT_PUSHPULLERR;
	}
	__skb_pull(ixs->skb, ixs->skb->nh.raw - ixs->skb->data);

	ipsec_nf_reset(ixs->skb);

	KLIPS_PRINT(debug_mast & DB_MAST_XMIT,
		    "klips_debug:ipsec_mast_send: "
		    "...done, calling ip_send() on device:%s\n",
		    ixs->skb->dev ? ixs->skb->dev->name : "NULL");
	KLIPS_IP_PRINT(debug_mast & DB_MAST_XMIT, ixs->skb->nh.iph);
	{
		int err;

		err = NF_HOOK(PF_INET, OSW_NF_INET_LOCAL_OUT, ixs->skb, NULL, ixs->route->u.dst.dev,
			      ipsec_mast_xmit2);
		if(err != NET_XMIT_SUCCESS && err != NET_XMIT_CN) {
			if(net_ratelimit())
				printk(KERN_ERR
				       "klips_error:ipsec_mast_send: "
				       "ip_send() failed, err=%d\n", 
				       -err);
			ixs->stats->tx_errors++;
			ixs->stats->tx_aborted_errors++;
			ixs->skb = NULL;
			return IPSEC_XMIT_IPSENDFAILURE;
		}
	}
	ixs->stats->tx_packets++;
        ixs->skb = NULL;

        return IPSEC_XMIT_OK;
}

int br_handle_frame(struct sk_buff *skb)
{
	struct net_bridge *br;
	unsigned char *dest;
	struct net_bridge_port *p;

	dest = skb->mac.ethernet->h_dest;

	p = skb->dev->br_port;
	if (p == NULL)
		goto err_nolock;

	br = p->br;
	read_lock(&br->lock);
	if (skb->dev->br_port == NULL)
		goto err;

	if (!(br->dev.flags & IFF_UP) ||
	    p->state == BR_STATE_DISABLED)
		goto err;

	if (skb->mac.ethernet->h_source[0] & 1)
		goto err;

	if (p->state == BR_STATE_LEARNING ||
	    p->state == BR_STATE_FORWARDING)
		br_fdb_insert(br, p, skb->mac.ethernet->h_source, 0);

	if (br->stp_enabled &&
	    !memcmp(dest, bridge_ula, 5) &&
	    !(dest[5] & 0xF0))
		goto handle_special_frame;

	if (p->state == BR_STATE_FORWARDING) {
		if (br_should_route_hook && br_should_route_hook(&skb)) {
			read_unlock(&br->lock);
			return -1;
		}

		NF_HOOK(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
			br_handle_frame_finish);
		read_unlock(&br->lock);
		return 0;
	}

err:
	read_unlock(&br->lock);
err_nolock:
	kfree_skb(skb);
	return 0;

handle_special_frame:
	if (!dest[5]) {
		br_stp_handle_bpdu(skb);
		read_unlock(&br->lock);
		return 0;
	}

	kfree_skb(skb);
	read_unlock(&br->lock);
	return 0;
}

//.........这里部分代码省略.........
	 */
	if (hdr->hop_limit <= 1) {
		/* Force OUTPUT device used as source address */
		skb->dev = dst->dev;
		icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
			    0, skb->dev);
		IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);

		kfree_skb(skb);
		return -ETIMEDOUT;
	}

	/* XXX: idev->cnf.proxy_ndp? */
	if (ipv6_devconf.proxy_ndp &&
	    pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) {
		int proxied = ip6_forward_proxy_check(skb);
		if (proxied > 0)
			return ip6_input(skb);
		else if (proxied < 0) {
			IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS);
			goto drop;
		}
	}

	if (!xfrm6_route_forward(skb)) {
		IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS);
		goto drop;
	}
	dst = skb->dst;

	/* IPv6 specs say nothing about it, but it is clear that we cannot
	   send redirects to source routed frames.
	   We don't send redirects to frames decapsulated from IPsec.
	 */
	if (skb->dev == dst->dev && dst->neighbour && opt->srcrt == 0 &&
	    !skb->sp) {
		struct in6_addr *target = NULL;
		struct rt6_info *rt;
		struct neighbour *n = dst->neighbour;

		/*
		 *	incoming and outgoing devices are the same
		 *	send a redirect.
		 */

		rt = (struct rt6_info *) dst;
		if ((rt->rt6i_flags & RTF_GATEWAY))
			target = (struct in6_addr*)&n->primary_key;
		else
			target = &hdr->daddr;

		/* Limit redirects both by destination (here)
		   and by source (inside ndisc_send_redirect)
		 */
		if (xrlim_allow(dst, 1*HZ))
			ndisc_send_redirect(skb, n, target);
	} else {
		int addrtype = ipv6_addr_type(&hdr->saddr);

		/* This check is security critical. */
		if (addrtype & (IPV6_ADDR_MULTICAST|IPV6_ADDR_LOOPBACK))
			goto error;
		if (addrtype & IPV6_ADDR_LINKLOCAL) {
			icmpv6_send(skb, ICMPV6_DEST_UNREACH,
				ICMPV6_NOT_NEIGHBOUR, 0, skb->dev);
			goto error;
		}
	}

	if (skb->len > dst_mtu(dst)) {
		/* Again, force OUTPUT device used as source address */
		skb->dev = dst->dev;
		icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, dst_mtu(dst), skb->dev);
		IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INTOOBIGERRORS);
		IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_FRAGFAILS);
		kfree_skb(skb);
		return -EMSGSIZE;
	}

	if (skb_cow(skb, dst->dev->hard_header_len)) {
		IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_OUTDISCARDS);
		goto drop;
	}

	hdr = ipv6_hdr(skb);

	/* Mangling hops number delayed to point after skb COW */

	hdr->hop_limit--;

	IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
	return NF_HOOK(PF_INET6, NF_INET_FORWARD, skb, skb->dev, dst->dev,
		       ip6_forward_finish);

error:
	IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS);
drop:
	kfree_skb(skb);
	return -EINVAL;
}

int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
	     struct ipv6_txoptions *opt, int ipfragok)
{
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct in6_addr *first_hop = &fl->fl6_dst;
	struct dst_entry *dst = skb->dst;
	struct ipv6hdr *hdr;
	u8  proto = fl->proto;
	int seg_len = skb->len;
	int hlimit, tclass;
	u32 mtu;

	if (opt) {
		unsigned int head_room;

		/* First: exthdrs may take lots of space (~8K for now)
		   MAX_HEADER is not enough.
		 */
		head_room = opt->opt_nflen + opt->opt_flen;
		seg_len += head_room;
		head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev);

		if (skb_headroom(skb) < head_room) {
			struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room);
			if (skb2 == NULL) {
				IP6_INC_STATS(ip6_dst_idev(skb->dst),
					      IPSTATS_MIB_OUTDISCARDS);
				kfree_skb(skb);
				return -ENOBUFS;
			}
			kfree_skb(skb);
			skb = skb2;
			if (sk)
				skb_set_owner_w(skb, sk);
		}
		if (opt->opt_flen)
			ipv6_push_frag_opts(skb, opt, &proto);
		if (opt->opt_nflen)
			ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop);
	}

	skb_push(skb, sizeof(struct ipv6hdr));
	skb_reset_network_header(skb);
	hdr = ipv6_hdr(skb);

	/* Allow local fragmentation. */
	if (ipfragok)
		skb->local_df = 1;

	/*
	 *	Fill in the IPv6 header
	 */

	hlimit = -1;
	if (np)
		hlimit = np->hop_limit;
	if (hlimit < 0)
		hlimit = ip6_dst_hoplimit(dst);

	tclass = -1;
	if (np)
		tclass = np->tclass;
	if (tclass < 0)
		tclass = 0;

	*(__be32 *)hdr = htonl(0x60000000 | (tclass << 20)) | fl->fl6_flowlabel;

	hdr->payload_len = htons(seg_len);
	hdr->nexthdr = proto;
	hdr->hop_limit = hlimit;

	ipv6_addr_copy(&hdr->saddr, &fl->fl6_src);
	ipv6_addr_copy(&hdr->daddr, first_hop);

	skb->priority = sk->sk_priority;
	skb->mark = sk->sk_mark;

	mtu = dst_mtu(dst);
	if ((skb->len <= mtu) || ipfragok || skb_is_gso(skb)) {
		IP6_INC_STATS(ip6_dst_idev(skb->dst),
			      IPSTATS_MIB_OUTREQUESTS);
		return NF_HOOK(PF_INET6, NF_INET_LOCAL_OUT, skb, NULL, dst->dev,
				dst_output);
	}

	if (net_ratelimit())
		printk(KERN_DEBUG "IPv6: sending pkt_too_big to self\n");
	skb->dev = dst->dev;
	icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev);
	IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGFAILS);
	kfree_skb(skb);
	return -EMSGSIZE;
}

/*
 *	Send an arp packet.
 */
void arp_xmit(struct sk_buff *skb)
{
	/* Send it off, maybe filter it using firewalling first.  */
	NF_HOOK(NFPROTO_ARP, NF_ARP_OUT, skb, NULL, skb->dev, dev_queue_xmit);
}

static void __br_deliver(struct net_bridge_port *to, struct sk_buff *skb)
{
	skb->dev = to->dev;
	NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
			__br_forward_finish);
}

int ip_forward(struct sk_buff *skb)
{
	struct iphdr *iph;	/* Our header */
	struct rtable *rt;	/* Route we use */
	struct ip_options * opt	= &(IPCB(skb)->opt);

	if (skb_warn_if_lro(skb))
		goto drop;

	if (!xfrm4_policy_check(NULL, XFRM_POLICY_FWD, skb))
		goto drop;

	if (IPCB(skb)->opt.router_alert && ip_call_ra_chain(skb))
		return NET_RX_SUCCESS;

	if (skb->pkt_type != PACKET_HOST)
		goto drop;

	skb_forward_csum(skb);

	/*
	 *	According to the RFC, we must first decrease the TTL field. If
	 *	that reaches zero, we must reply an ICMP control message telling
	 *	that the packet's lifetime expired.
	 */
	if (ip_hdr(skb)->ttl <= 1)
		goto too_many_hops;

	if (!xfrm4_route_forward(skb))
		goto drop;

	rt = skb->rtable;

	if (opt->is_strictroute && rt->rt_dst != rt->rt_gateway)
		goto sr_failed;

	if (unlikely(skb->len > dst_mtu(&rt->u.dst) && !skb_is_gso(skb) &&
		     (ip_hdr(skb)->frag_off & htons(IP_DF))) && !skb->local_df) {
		IP_INC_STATS(dev_net(rt->u.dst.dev), IPSTATS_MIB_FRAGFAILS);
		icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
			  htonl(dst_mtu(&rt->u.dst)));
		goto drop;
	}

	/* We are about to mangle packet. Copy it! */
	if (skb_cow(skb, LL_RESERVED_SPACE(rt->u.dst.dev)+rt->u.dst.header_len))
		goto drop;
	iph = ip_hdr(skb);

	/* Decrease ttl after skb cow done */
	ip_decrease_ttl(iph);

	/*
	 *	We now generate an ICMP HOST REDIRECT giving the route
	 *	we calculated.
	 */
	if (rt->rt_flags&RTCF_DOREDIRECT && !opt->srr && !skb_sec_path(skb))
		ip_rt_send_redirect(skb);

	skb->priority = rt_tos2priority(iph->tos);

	return NF_HOOK(PF_INET, NF_INET_FORWARD, skb, skb->dev, rt->u.dst.dev,
		       ip_forward_finish);

sr_failed:
	/*
	 *	Strict routing permits no gatewaying
	 */
	 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_SR_FAILED, 0);
	 goto drop;

too_many_hops:
	/* Tell the sender its packet died... */
	IP_INC_STATS_BH(dev_net(skb->dst->dev), IPSTATS_MIB_INHDRERRORS);
	icmp_send(skb, ICMP_TIME_EXCEEDED, ICMP_EXC_TTL, 0);
drop:
	kfree_skb(skb);
	return NET_RX_DROP;
}