C++ skb_cloned函数代码示例

static unsigned int
fw_in(unsigned int hooknum,
      struct sk_buff **pskb,
      const struct net_device *in,
      const struct net_device *out,
      int (*okfn)(struct sk_buff *))
{
	int ret = FW_BLOCK;
	u_int16_t redirpt;

	/* Assume worse case: any hook could change packet */
	(*pskb)->nfcache |= NFC_UNKNOWN | NFC_ALTERED;
	if ((*pskb)->ip_summed == CHECKSUM_HW)
		(*pskb)->ip_summed = CHECKSUM_NONE;

	/* Firewall rules can alter TOS: raw socket (tcpdump) may have
           clone of incoming skb: don't disturb it --RR */
	if (skb_cloned(*pskb) && !(*pskb)->sk) {
		struct sk_buff *nskb = skb_copy(*pskb, GFP_ATOMIC);
		if (!nskb)
			return NF_DROP;
		kfree_skb(*pskb);
		*pskb = nskb;
	}

	switch (hooknum) {
	case NF_IP_PRE_ROUTING:
		if (fwops->fw_acct_in)
			fwops->fw_acct_in(fwops, PF_INET,
					  (struct net_device *)in,
					  (*pskb)->nh.raw, &redirpt, pskb);

		if ((*pskb)->nh.iph->frag_off & htons(IP_MF|IP_OFFSET)) {
			*pskb = ip_ct_gather_frags(*pskb, IP_DEFRAG_CONNTRACK_IN);

			if (!*pskb)
				return NF_STOLEN;
		}

		ret = fwops->fw_input(fwops, PF_INET, (struct net_device *)in,
				      (*pskb)->nh.raw, &redirpt, pskb);
		break;

	case NF_IP_FORWARD:
		/* Connection will only be set if it was
                   demasqueraded: if so, skip forward chain. */
		if ((*pskb)->nfct)
			ret = FW_ACCEPT;
		else ret = fwops->fw_forward(fwops, PF_INET,
					     (struct net_device *)out,
					     (*pskb)->nh.raw, &redirpt, pskb);
		break;

	case NF_IP_POST_ROUTING:
		ret = fwops->fw_output(fwops, PF_INET,
				       (struct net_device *)out,
				       (*pskb)->nh.raw, &redirpt, pskb);
		if (ret == FW_ACCEPT || ret == FW_SKIP) {
			if (fwops->fw_acct_out)
				fwops->fw_acct_out(fwops, PF_INET,
						   (struct net_device *)out,
						   (*pskb)->nh.raw, &redirpt,
						   pskb);

			/* ip_conntrack_confirm return NF_DROP or NF_ACCEPT */
			if (ip_conntrack_confirm(hooknum, *pskb) == NF_DROP)
				ret = FW_BLOCK;
		}
		break;
	}

	switch (ret) {
	case FW_REJECT: {
		/* Alexey says:
		 *
		 * Generally, routing is THE FIRST thing to make, when
		 * packet enters IP stack. Before packet is routed you
		 * cannot call any service routines from IP stack.  */
		struct iphdr *iph = (*pskb)->nh.iph;

		if ((*pskb)->dst != NULL
		    || ip_route_input(*pskb, iph->daddr, iph->saddr, iph->tos,
				      (struct net_device *)in) == 0)
			icmp_send(*pskb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH,
				  0);
		return NF_DROP;
	}

	case FW_ACCEPT:
	case FW_SKIP:
		if (hooknum == NF_IP_PRE_ROUTING) {
			check_for_demasq(pskb);
			check_for_redirect(*pskb);
		} else if (hooknum == NF_IP_POST_ROUTING) {
			check_for_unredirect(*pskb);
			/* Handle ICMP errors from client here */
			if ((*pskb)->nh.iph->protocol == IPPROTO_ICMP
			    && (*pskb)->nfct)
				check_for_masq_error(*pskb);
		}
//.........这里部分代码省略.........

static struct sk_buff *vl600_tx_fixup(struct usbnet *dev,
		struct sk_buff *skb, gfp_t flags)
{
	struct sk_buff *ret;
	struct vl600_frame_hdr *frame;
	struct vl600_pkt_hdr *packet;
	static uint32_t serial = 1;
	int orig_len = skb->len - sizeof(struct ethhdr);
	int full_len = (skb->len + sizeof(struct vl600_frame_hdr) + 3) & ~3;

	frame = (struct vl600_frame_hdr *) skb->data;
	if (skb->len > sizeof(*frame) && skb->len == le32_to_cpup(&frame->len))
		return skb; /* Already encapsulated? */

	if (skb->len < sizeof(struct ethhdr))
		/* Drop, device can only deal with ethernet packets */
		return NULL;

	if (!skb_cloned(skb)) {
		int headroom = skb_headroom(skb);
		int tailroom = skb_tailroom(skb);

		if (tailroom >= full_len - skb->len - sizeof(*frame) &&
				headroom >= sizeof(*frame))
			/* There's enough head and tail room */
			goto encapsulate;

		if (headroom + tailroom + skb->len >= full_len) {
			/* There's enough total room, just readjust */
			skb->data = memmove(skb->head + sizeof(*frame),
					skb->data, skb->len);
			skb_set_tail_pointer(skb, skb->len);
			goto encapsulate;
		}
	}

	/* Alloc a new skb with the required size */
	ret = skb_copy_expand(skb, sizeof(struct vl600_frame_hdr), full_len -
			skb->len - sizeof(struct vl600_frame_hdr), flags);
	dev_kfree_skb_any(skb);
	if (!ret)
		return ret;
	skb = ret;

encapsulate:
	/* Packet header is same size as ethernet packet header
	 * (sizeof(*packet) == sizeof(struct ethhdr)), additionally the
	 * h_proto field is in the same place so we just leave it alone and
	 * overwrite the remaining fields.
	 */
	packet = (struct vl600_pkt_hdr *) skb->data;
	/* The VL600 wants IPv6 packets to have an IPv4 ethertype
	 * Since this modem only supports IPv4 and IPv6, just set all
	 * frames to 0x0800 (ETH_P_IP)
	 */
	packet->h_proto = htons(ETH_P_IP);
	memset(&packet->dummy, 0, sizeof(packet->dummy));
	packet->len = cpu_to_le32(orig_len);

	frame = (struct vl600_frame_hdr *) skb_push(skb, sizeof(*frame));
	memset(frame, 0, sizeof(*frame));
	frame->len = cpu_to_le32(full_len);
	frame->serial = cpu_to_le32(serial++);
	frame->pkt_cnt = cpu_to_le32(1);

	if (skb->len < full_len) /* Pad */
		skb_put(skb, full_len - skb->len);

	return skb;
}

static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
{
	struct net_device *dev;
	struct sk_buff *frag;
	struct rt6_info *rt = (struct rt6_info*)skb->dst;
	struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL;
	struct ipv6hdr *tmp_hdr;
	struct frag_hdr *fh;
	unsigned int mtu, hlen, left, len;
	__be32 frag_id = 0;
	int ptr, offset = 0, err=0;
	u8 *prevhdr, nexthdr = 0;

	dev = rt->u.dst.dev;
	hlen = ip6_find_1stfragopt(skb, &prevhdr);
	nexthdr = *prevhdr;

	mtu = ip6_skb_dst_mtu(skb);

	/* We must not fragment if the socket is set to force MTU discovery
	 * or if the skb it not generated by a local socket.  (This last
	 * check should be redundant, but it's free.)
	 */
	if (!np || np->pmtudisc >= IPV6_PMTUDISC_DO) {
		skb->dev = skb->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;
	}

	if (np && np->frag_size < mtu) {
		if (np->frag_size)
			mtu = np->frag_size;
	}
	mtu -= hlen + sizeof(struct frag_hdr);

	if (skb_shinfo(skb)->frag_list) {
		int first_len = skb_pagelen(skb);
		int truesizes = 0;

		if (first_len - hlen > mtu ||
		    ((first_len - hlen) & 7) ||
		    skb_cloned(skb))
			goto slow_path;

		for (frag = skb_shinfo(skb)->frag_list; frag; frag = frag->next) {
			/* Correct geometry. */
			if (frag->len > mtu ||
			    ((frag->len & 7) && frag->next) ||
			    skb_headroom(frag) < hlen)
			    goto slow_path;

			/* Partially cloned skb? */
			if (skb_shared(frag))
				goto slow_path;

			BUG_ON(frag->sk);
			if (skb->sk) {
				sock_hold(skb->sk);
				frag->sk = skb->sk;
				frag->destructor = sock_wfree;
				truesizes += frag->truesize;
			}
		}

		err = 0;
		offset = 0;
		frag = skb_shinfo(skb)->frag_list;
		skb_shinfo(skb)->frag_list = NULL;
		/* BUILD HEADER */

		*prevhdr = NEXTHDR_FRAGMENT;
		tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);
		if (!tmp_hdr) {
			IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGFAILS);
			return -ENOMEM;
		}

		__skb_pull(skb, hlen);
		fh = (struct frag_hdr*)__skb_push(skb, sizeof(struct frag_hdr));
		__skb_push(skb, hlen);
		skb_reset_network_header(skb);
		memcpy(skb_network_header(skb), tmp_hdr, hlen);

		ipv6_select_ident(skb, fh);
		fh->nexthdr = nexthdr;
		fh->reserved = 0;
		fh->frag_off = htons(IP6_MF);
		frag_id = fh->identification;

		first_len = skb_pagelen(skb);
		skb->data_len = first_len - skb_headlen(skb);
		skb->truesize -= truesizes;
		skb->len = first_len;
		ipv6_hdr(skb)->payload_len = htons(first_len -
						   sizeof(struct ipv6hdr));

		dst_hold(&rt->u.dst);

//.........这里部分代码省略.........

static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev,
			 struct net_device *dev)
{
	struct net *net = container_of(qp->q.net, struct net, ipv4.frags);
	struct iphdr *iph;
	struct sk_buff *fp, *head = qp->q.fragments;
	int len;
	int ihlen;
	int err;
	u8 ecn;

	ipq_kill(qp);

	ecn = ip4_frag_ecn_table[qp->ecn];
	if (unlikely(ecn == 0xff)) {
		err = -EINVAL;
		goto out_fail;
	}
	/* Make the one we just received the head. */
	if (prev) {
		head = prev->next;
		fp = skb_clone(head, GFP_ATOMIC);
		if (!fp)
			goto out_nomem;

		fp->next = head->next;
		if (!fp->next)
			qp->q.fragments_tail = fp;
		prev->next = fp;

		skb_morph(head, qp->q.fragments);
		head->next = qp->q.fragments->next;

		kfree_skb(qp->q.fragments);
		qp->q.fragments = head;
	}

	WARN_ON(head == NULL);
	WARN_ON(FRAG_CB(head)->offset != 0);

	/* Allocate a new buffer for the datagram. */
	ihlen = ip_hdrlen(head);
	len = ihlen + qp->q.len;

	err = -E2BIG;
	if (len > 65535)
		goto out_oversize;

	/* Head of list must not be cloned. */
	if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
		goto out_nomem;

	/* If the first fragment is fragmented itself, we split
	 * it to two chunks: the first with data and paged part
	 * and the second, holding only fragments. */
	if (skb_has_frag_list(head)) {
		struct sk_buff *clone;
		int i, plen = 0;

		if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
			goto out_nomem;
		clone->next = head->next;
		head->next = clone;
		skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
		skb_frag_list_init(head);
		for (i=0; i<skb_shinfo(head)->nr_frags; i++)
			plen += skb_shinfo(head)->frags[i].size;
		clone->len = clone->data_len = head->data_len - plen;
		head->data_len -= clone->len;
		head->len -= clone->len;
		clone->csum = 0;
		clone->ip_summed = head->ip_summed;
		atomic_add(clone->truesize, &qp->q.net->mem);
	}

	skb_shinfo(head)->frag_list = head->next;
	skb_push(head, head->data - skb_network_header(head));

	for (fp=head->next; fp; fp = fp->next) {
		head->data_len += fp->len;
		head->len += fp->len;
		if (head->ip_summed != fp->ip_summed)
			head->ip_summed = CHECKSUM_NONE;
		else if (head->ip_summed == CHECKSUM_COMPLETE)
			head->csum = csum_add(head->csum, fp->csum);
		head->truesize += fp->truesize;
	}
	atomic_sub(head->truesize, &qp->q.net->mem);

	head->next = NULL;
	head->dev = dev;
	head->tstamp = qp->q.stamp;

	iph = ip_hdr(head);
	iph->frag_off = 0;
	iph->tot_len = htons(len);
	iph->tos |= ecn;
	IP_INC_STATS_BH(net, IPSTATS_MIB_REASMOKS);
	qp->q.fragments = NULL;
	qp->q.fragments_tail = NULL;
//.........这里部分代码省略.........

int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type)
{
	int err;
	u32 spi, seq;
	struct sec_decap_state xfrm_vec[XFRM_MAX_DEPTH];
	struct xfrm_state *x;
	int xfrm_nr = 0;
	int decaps = 0;
	int offset = 0;

	if ((err = xfrm4_parse_spi(skb, skb->nh.iph->protocol, &spi, &seq)) != 0)
		goto drop;

	do {
		struct iphdr *iph = skb->nh.iph;

		if (xfrm_nr == XFRM_MAX_DEPTH)
			goto drop;

		x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, iph->protocol, AF_INET);
		if (x == NULL)
			goto drop;

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

#if defined(CONFIG_CAVIUM_OCTEON_IPSEC) && defined(CONFIG_NET_KEY) 
		/*
	  	 * If Octeon IPSEC Acceleration module has been loaded
		 * call it, otherwise, follow the software path
		 */
		if(cavium_ipsec_process)
		{
			if (xfrm_state_check_expire(x))
				goto drop_unlock;

			xfrm_vec[xfrm_nr].decap.decap_type = encap_type;
    
			switch (skb->nh.iph->protocol) {
       			case IPPROTO_AH:
					offset = offsetof(struct ip_auth_hdr, nexthdr);
					break;
				case IPPROTO_ESP:
        			offset = offsetof(struct ip_esp_hdr, spi);
					break;
				default:
					return -skb->nh.iph->protocol;
			}
			offset += (uint64_t)skb->data - (uint64_t)skb->nh.iph;
			/*
		 	 * skb->data points to the start of the esp/ah header
			 * but we require skb->data to point to the start of ip header.
			 */
			skb_push(skb, (unsigned int)((uint64_t)skb->data - (uint64_t)skb->nh.iph));
			if (skb_is_nonlinear(skb) &&
				skb_linearize(skb, GFP_ATOMIC) != 0) {
				err = -ENOMEM;
				goto drop_unlock;
	        }
			if (skb_cloned(skb) &&
				pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
            {
                err = -ENOMEM;
			    goto drop_unlock;
            }

			err = cavium_ipsec_process(x->sa_handle, skb, offset, 0 /*DECRYPT*/);
			if(err) 
				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 0
				if (skb_cloned(skb) &&
					pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
				goto drop;

			/* 
			 * TODO, support ECN and dscp decapsulation
			 */
				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);
#endif
				skb->nh.raw = skb->data;
				memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
				decaps = 1;
				break;
//.........这里部分代码省略.........

void sendPSDData(int cid, struct sk_buff *skb)
{
	struct pduhdr *hdr;
	struct sk_buff *skb2;
	unsigned len;
	unsigned tailpad;
	unsigned long flags;

	len = skb->len;
	tailpad = padding_size(sizeof *hdr + len);

	if (likely(!skb_cloned(skb))) {
		int	headroom = skb_headroom(skb);
		int tailroom = skb_tailroom(skb);

		/* enough room as-is? */
		if (likely(sizeof *hdr + tailpad <= headroom + tailroom)) {
			/* do not need to be readjusted */
			if(sizeof *hdr <= headroom && tailpad <= tailroom)
				goto fill;

			skb->data = memmove(skb->head + sizeof *hdr,
				skb->data, len);
			skb_set_tail_pointer(skb, len);
			goto fill;
		}
	}

	/* create a new skb, with the correct size (and tailpad) */
	skb2 = skb_copy_expand(skb, sizeof *hdr, tailpad + 1, GFP_ATOMIC);
	dev_kfree_skb_any(skb);
	if (unlikely(!skb2))
		return;
	skb = skb2;

	/* fill out the pdu header */
fill:
	hdr = (void *) __skb_push(skb, sizeof *hdr);
	memset(hdr, 0, sizeof *hdr);
	hdr->length = cpu_to_be16(len);
	hdr->cid = cid;
	memset(skb_put(skb, tailpad), 0, tailpad);

	/* link is down */
	if(!data_path_is_link_up()) {
		dev_kfree_skb_any(skb);
		return;
	}

	spin_lock_irqsave(&tx_q_lock, flags);
	/* drop the packet if queue is full */
	if (skb_queue_len(&tx_q) >= PSD_TX_QUEUE_MAX_LEN) {
		struct sk_buff *first = skb_dequeue(&tx_q);
		dev_kfree_skb_any(first);
	}

	skb_queue_tail(&tx_q, skb);
	spin_unlock_irqrestore(&tx_q_lock, flags);

	data_path_schedule_tx(psd_dp);
}

static int ah6_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
{
	/*
	 * Before process AH
	 * [IPv6][Ext1][Ext2][AH][Dest][Payload]
	 * |<-------------->| hdr_len
	 *
	 * To erase AH:
	 * Keeping copy of cleared headers. After AH processing,
	 * Moving the pointer of skb->nh.raw by using skb_pull as long as AH
	 * header length. Then copy back the copy as long as hdr_len
	 * If destination header following AH exists, copy it into after [Ext2].
	 * 
	 * |<>|[IPv6][Ext1][Ext2][Dest][Payload]
	 * There is offset of AH before IPv6 header after the process.
	 */

	struct ipv6_auth_hdr *ah;
	struct ah_data *ahp;
	unsigned char *tmp_hdr = NULL;
	u16 hdr_len;
	u16 ah_hlen;
	int nexthdr;

	if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
		goto out;

	/* We are going to _remove_ AH header to keep sockets happy,
	 * so... Later this can change. */
	if (skb_cloned(skb) &&
	    pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
		goto out;

	hdr_len = skb->data - skb->nh.raw;
	ah = (struct ipv6_auth_hdr*)skb->data;
	ahp = x->data;
	nexthdr = ah->nexthdr;
	ah_hlen = (ah->hdrlen + 2) << 2;

        if (ah_hlen != XFRM_ALIGN8(sizeof(struct ipv6_auth_hdr) + ahp->icv_full_len) &&
            ah_hlen != XFRM_ALIGN8(sizeof(struct ipv6_auth_hdr) + ahp->icv_trunc_len))
                goto out;

	if (!pskb_may_pull(skb, ah_hlen))
		goto out;

	tmp_hdr = kmalloc(hdr_len, GFP_ATOMIC);
	if (!tmp_hdr)
		goto out;
	memcpy(tmp_hdr, skb->nh.raw, hdr_len);
	if (ipv6_clear_mutable_options(skb->nh.ipv6h, hdr_len))
		goto out;
	skb->nh.ipv6h->priority    = 0;
	skb->nh.ipv6h->flow_lbl[0] = 0;
	skb->nh.ipv6h->flow_lbl[1] = 0;
	skb->nh.ipv6h->flow_lbl[2] = 0;
	skb->nh.ipv6h->hop_limit   = 0;

        {
		u8 auth_data[MAX_AH_AUTH_LEN];

		memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
		memset(ah->auth_data, 0, ahp->icv_trunc_len);
		skb_push(skb, skb->data - skb->nh.raw);
		ahp->icv(ahp, skb, ah->auth_data);
		if (memcmp(ah->auth_data, auth_data, ahp->icv_trunc_len)) {
			LIMIT_NETDEBUG(
				printk(KERN_WARNING "ipsec ah authentication error\n"));
			x->stats.integrity_failed++;
			goto free_out;
		}
	}

	skb->nh.raw = skb_pull(skb, ah_hlen);
	memcpy(skb->nh.raw, tmp_hdr, hdr_len);
	skb->nh.ipv6h->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
	skb_pull(skb, hdr_len);
	skb->h.raw = skb->data;


	kfree(tmp_hdr);

	return nexthdr;

free_out:
	kfree(tmp_hdr);
out:
	return -EINVAL;
}

static struct sk_buff *
kalmia_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
{
	struct sk_buff *skb2 = NULL;
	u16 content_len;
	unsigned char *header_start;
	unsigned char ether_type_1, ether_type_2;
	u8 remainder, padlen = 0;

	if (!skb_cloned(skb)) {
		int headroom = skb_headroom(skb);
		int tailroom = skb_tailroom(skb);

		if ((tailroom >= KALMIA_ALIGN_SIZE) && (headroom
			>= KALMIA_HEADER_LENGTH))
			goto done;

		if ((headroom + tailroom) > (KALMIA_HEADER_LENGTH
			+ KALMIA_ALIGN_SIZE)) {
			skb->data = memmove(skb->head + KALMIA_HEADER_LENGTH,
				skb->data, skb->len);
			skb_set_tail_pointer(skb, skb->len);
			goto done;
		}
	}

	skb2 = skb_copy_expand(skb, KALMIA_HEADER_LENGTH,
		KALMIA_ALIGN_SIZE, flags);
	if (!skb2)
		return NULL;

	dev_kfree_skb_any(skb);
	skb = skb2;

done:
	header_start = skb_push(skb, KALMIA_HEADER_LENGTH);
	ether_type_1 = header_start[KALMIA_HEADER_LENGTH + 12];
	ether_type_2 = header_start[KALMIA_HEADER_LENGTH + 13];

	netdev_dbg(dev->net, "Sending etherType: %02x%02x", ether_type_1,
		ether_type_2);

	/* According to empiric data for data packages */
	header_start[0] = 0x57;
	header_start[1] = 0x44;
	content_len = skb->len - KALMIA_HEADER_LENGTH;

	put_unaligned_le16(content_len, &header_start[2]);
	header_start[4] = ether_type_1;
	header_start[5] = ether_type_2;

	/* Align to 4 bytes by padding with zeros */
	remainder = skb->len % KALMIA_ALIGN_SIZE;
	if (remainder > 0) {
		padlen = KALMIA_ALIGN_SIZE - remainder;
		memset(skb_put(skb, padlen), 0, padlen);
	}

	netdev_dbg(
		dev->net,
		"Sending package with length %i and padding %i. Header: %02x:%02x:%02x:%02x:%02x:%02x.",
		content_len, padlen, header_start[0], header_start[1],
		header_start[2], header_start[3], header_start[4],
		header_start[5]);

	return skb;
}

static struct sk_buff *
mvswitch_mangle_tx(struct net_device *dev, struct sk_buff *skb)
{
	struct mvswitch_priv *priv;
	char *buf = NULL;
	u16 vid;

	priv = dev->phy_ptr;
	if (unlikely(!priv))
		goto error;

	if (unlikely(skb->len < 16))
		goto error;

#ifdef HEADER_MODE
	if (__vlan_hwaccel_get_tag(skb, &vid))
		goto error;

	if (skb_cloned(skb) || (skb->len <= 62) || (skb_headroom(skb) < MV_HEADER_SIZE)) {
		if (pskb_expand_head(skb, MV_HEADER_SIZE, (skb->len < 62 ? 62 - skb->len : 0), GFP_ATOMIC))
			goto error_expand;
		if (skb->len < 62)
			skb->len = 62;
	}
	buf = skb_push(skb, MV_HEADER_SIZE);
#else
	if (__vlan_get_tag(skb, &vid))
		goto error;

	if (unlikely((vid > 15 || !priv->vlans[vid])))
		goto error;

	if (skb->len <= 64) {
		if (pskb_expand_head(skb, 0, 64 + MV_TRAILER_SIZE - skb->len, GFP_ATOMIC))
			goto error_expand;

		buf = skb->data + 64;
		skb->len = 64 + MV_TRAILER_SIZE;
	} else {
		if (skb_cloned(skb) || unlikely(skb_tailroom(skb) < 4)) {
			if (pskb_expand_head(skb, 0, 4, GFP_ATOMIC))
				goto error_expand;
		}
		buf = skb_put(skb, 4);
	}

	/* move the ethernet header 4 bytes forward, overwriting the vlan tag */
	memmove(skb->data + 4, skb->data, 12);
	skb->data += 4;
	skb->len -= 4;
	skb->mac_header += 4;
#endif

	if (!buf)
		goto error;


#ifdef HEADER_MODE
	/* prepend the tag */
	*((__be16 *) buf) = cpu_to_be16(
		((vid << MV_HEADER_VLAN_S) & MV_HEADER_VLAN_M) |
		((priv->vlans[vid] << MV_HEADER_PORTS_S) & MV_HEADER_PORTS_M)
	);
#else
	/* append the tag */
	*((__be32 *) buf) = cpu_to_be32((
		(MV_TRAILER_OVERRIDE << MV_TRAILER_FLAGS_S) |
		((priv->vlans[vid] & MV_TRAILER_PORTS_M) << MV_TRAILER_PORTS_S)
	));
#endif

	return skb;

error_expand:
	if (net_ratelimit())
		printk("%s: failed to expand/update skb for the switch\n", dev->name);

error:
	/* any errors? drop the packet! */
	dev_kfree_skb_any(skb);
	return NULL;
}

//.........这里部分代码省略.........
			goto tx_error;
		}
		break;

#ifdef CONFIG_NET_IPIP_IPV6
	case __constant_htons(ETH_P_IPV6):
#if 0
		if (mtu < IPV6_MIN_MTU) {
			/* XXX: too small; we should fragment this packet? */
			tunnel->stat.tx_carrier_errors++;
			goto tx_error_icmp;
		}
#endif
		if (skb->len > mtu && mtu > IPV6_MIN_MTU) {
			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
			ip_rt_put(rt);
			goto tx_error;
		}
		df = mtu > IPV6_MIN_MTU ? htons(IP_DF) : 0;
		break;
#endif
	}
	if (tunnel->err_count > 0) {
		if (jiffies - tunnel->err_time < IPTUNNEL_ERR_TIMEO) {
			tunnel->err_count--;
			dst_link_failure(skb);
		} else
			tunnel->err_count = 0;
	}

	/*
	 * Okay, now see if we can stuff it in the buffer as-is.
	 */
	max_headroom = (((tdev->hard_header_len+15)&~15)+sizeof(struct iphdr));
	if (skb_headroom(skb) < max_headroom || skb_cloned(skb) || skb_shared(skb)) {
		struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
		if (!new_skb) {
			ip_rt_put(rt);
  			stats->tx_dropped++;
			dev_kfree_skb(skb);
			tunnel->recursion--;
			return 0;
		}
		if (skb->sk)
			skb_set_owner_w(new_skb, skb->sk);
		dev_kfree_skb(skb);
		skb = new_skb;
		old_iph = skb->nh.iph;
	}

	skb->h.raw = skb->nh.raw;
	skb->nh.raw = skb_push(skb, sizeof(struct iphdr));
	memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
	dst_release(skb->dst);
	skb->dst = &rt->u.dst;

	/*
	 *	Push down and install the IPIP header.
	 */

	iph 			=	skb->nh.iph;
	iph->version		=	4;
	iph->ihl		=	sizeof(struct iphdr)>>2;
	iph->daddr		=	rt->rt_dst;
	iph->saddr		=	rt->rt_src;

	iph->ttl		=	tiph->ttl;
	iph->frag_off		=	df;

	switch(skb->protocol){
	case __constant_htons(ETH_P_IP):
		iph->protocol	=	protocol;
		iph->tos	=	INET_ECN_encapsulate(tos, old_iph->tos);
		if (iph->ttl == 0)
			iph->ttl =	old_iph->ttl;
		break;
#ifdef CONFIG_NET_IPIP_IPV6
	case __constant_htons(ETH_P_IPV6):
		iph->protocol	=	protocol;
		iph->tos	=	INET_ECN_encapsulate(tos, ip6_get_dsfield(iph6));
		if (iph->ttl == 0)
			iph->ttl =	iph6->hop_limit;
		break;
#endif
	}

	nf_reset(skb);

	IPTUNNEL_XMIT();
	tunnel->recursion--;
	return 0;

tx_error_icmp:
	dst_link_failure(skb);
tx_error:
	stats->tx_errors++;
	dev_kfree_skb(skb);
	tunnel->recursion--;
	return 0;
}

int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type)
{
	int err;
	u32 spi, seq;
	struct sec_decap_state xfrm_vec[XFRM_MAX_DEPTH];
	struct xfrm_state *x;
	int xfrm_nr = 0;
	int decaps = 0;

	if ((err = xfrm4_parse_spi(skb, skb->nh.iph->protocol, &spi, &seq)) != 0)
		goto drop;

	do {
		struct iphdr *iph = skb->nh.iph;

		if (xfrm_nr == XFRM_MAX_DEPTH)
			goto drop;

		x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, iph->protocol, AF_INET);
		if (x == NULL)
			goto drop;

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

		if (x->props.replay_window && xfrm_replay_check(x, seq))
			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;

		if (x->props.replay_window)
			xfrm_replay_advance(x, seq);

		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, &seq)) < 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);
//.........这里部分代码省略.........

static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
			  struct net_device *dev)
{
	struct net *net = container_of(fq->q.net, struct net, ipv6.frags);
	struct sk_buff *fp, *head = fq->q.fragments;
	int    payload_len;
	unsigned int nhoff;

	fq_kill(fq);

	
	if (prev) {
		head = prev->next;
		fp = skb_clone(head, GFP_ATOMIC);

		if (!fp)
			goto out_oom;

		fp->next = head->next;
		if (!fp->next)
			fq->q.fragments_tail = fp;
		prev->next = fp;

		skb_morph(head, fq->q.fragments);
		head->next = fq->q.fragments->next;

		kfree_skb(fq->q.fragments);
		fq->q.fragments = head;
	}

	WARN_ON(head == NULL);
	WARN_ON(FRAG6_CB(head)->offset != 0);

	
	payload_len = ((head->data - skb_network_header(head)) -
		       sizeof(struct ipv6hdr) + fq->q.len -
		       sizeof(struct frag_hdr));
	if (payload_len > IPV6_MAXPLEN)
		goto out_oversize;

	
	if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
		goto out_oom;

	if (skb_has_frag_list(head)) {
		struct sk_buff *clone;
		int i, plen = 0;

		if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
			goto out_oom;
		clone->next = head->next;
		head->next = clone;
		skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
		skb_frag_list_init(head);
		for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
			plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
		clone->len = clone->data_len = head->data_len - plen;
		head->data_len -= clone->len;
		head->len -= clone->len;
		clone->csum = 0;
		clone->ip_summed = head->ip_summed;
		atomic_add(clone->truesize, &fq->q.net->mem);
	}

	nhoff = fq->nhoffset;
	skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
	memmove(head->head + sizeof(struct frag_hdr), head->head,
		(head->data - head->head) - sizeof(struct frag_hdr));
	head->mac_header += sizeof(struct frag_hdr);
	head->network_header += sizeof(struct frag_hdr);

	skb_shinfo(head)->frag_list = head->next;
	skb_reset_transport_header(head);
	skb_push(head, head->data - skb_network_header(head));

	for (fp=head->next; fp; fp = fp->next) {
		head->data_len += fp->len;
		head->len += fp->len;
		if (head->ip_summed != fp->ip_summed)
			head->ip_summed = CHECKSUM_NONE;
		else if (head->ip_summed == CHECKSUM_COMPLETE)
			head->csum = csum_add(head->csum, fp->csum);
		head->truesize += fp->truesize;
	}
	atomic_sub(head->truesize, &fq->q.net->mem);

	head->next = NULL;
	head->dev = dev;
	head->tstamp = fq->q.stamp;
	ipv6_hdr(head)->payload_len = htons(payload_len);
	IP6CB(head)->nhoff = nhoff;

	
	if (head->ip_summed == CHECKSUM_COMPLETE)
		head->csum = csum_partial(skb_network_header(head),
					  skb_network_header_len(head),
					  head->csum);

	rcu_read_lock();
	IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMOKS);
//.........这里部分代码省略.........

static int ah_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
{
	int ah_hlen;
	struct iphdr *iph;
	struct ip_auth_hdr *ah;
	struct ah_data *ahp;
	char work_buf[60];

	if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
		goto out;

	ah = (struct ip_auth_hdr*)skb->data;
	if (x->props.replay_window && xfrm_replay_check(x, ah->seq_no))
		goto out;
	ahp = x->data;
	ah_hlen = (ah->hdrlen + 2) << 2;
	
	if (ah_hlen != XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + ahp->icv_full_len) &&
	    ah_hlen != XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + ahp->icv_trunc_len)) 
		goto out;

	if (!pskb_may_pull(skb, ah_hlen))
		goto out;

	/* We are going to _remove_ AH header to keep sockets happy,
	 * so... Later this can change. */
	if (skb_cloned(skb) &&
	    pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
		goto out;

	skb->ip_summed = CHECKSUM_NONE;

	ah = (struct ip_auth_hdr*)skb->data;
	iph = skb->nh.iph;

	memcpy(work_buf, iph, iph->ihl*4);

	iph->ttl = 0;
	iph->tos = 0;
	iph->frag_off = 0;
	iph->check = 0;
	if (iph->ihl != 5) {
		u32 dummy;
		if (ip_clear_mutable_options(iph, &dummy))
			goto out;
	}
        {
		u8 auth_data[MAX_AH_AUTH_LEN];
		
		memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
		skb_push(skb, skb->data - skb->nh.raw);
		ahp->icv(ahp, skb, ah->auth_data);
		if (memcmp(ah->auth_data, auth_data, ahp->icv_trunc_len)) {
			x->stats.integrity_failed++;
			goto out;
		}
	}
	if (x->props.replay_window)
		xfrm_replay_advance(x, ah->seq_no);
	((struct iphdr*)work_buf)->protocol = ah->nexthdr;
	skb->nh.raw = skb_pull(skb, ah_hlen);
	memcpy(skb->nh.raw, work_buf, iph->ihl*4);
	skb->nh.iph->tot_len = htons(skb->len);
	skb_pull(skb, skb->nh.iph->ihl*4);
	skb->h.raw = skb->data;

	return 0;

out:
	return -EINVAL;
}

int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer)
{
	int copyflag;
	int elt;
	struct sk_buff *skb1, **skb_p;

	/* If skb is cloned or its head is paged, reallocate
	 * head pulling out all the pages (pages are considered not writable
	 * at the moment even if they are anonymous).
	 */
	if ((skb_cloned(skb) || skb_shinfo(skb)->nr_frags) &&
	    __pskb_pull_tail(skb, skb_pagelen(skb)-skb_headlen(skb)) == NULL)
		return -ENOMEM;

	/* Easy case. Most of packets will go this way. */
	if (!skb_shinfo(skb)->frag_list) {
		/* A little of trouble, not enough of space for trailer.
		 * This should not happen, when stack is tuned to generate
		 * good frames. OK, on miss we reallocate and reserve even more
		 * space, 128 bytes is fair. */

		if (skb_tailroom(skb) < tailbits &&
		    pskb_expand_head(skb, 0, tailbits-skb_tailroom(skb)+128, GFP_ATOMIC))
			return -ENOMEM;

		/* Voila! */
		*trailer = skb;
		return 1;
	}

	/* Misery. We are in troubles, going to mincer fragments... */

	elt = 1;
	skb_p = &skb_shinfo(skb)->frag_list;
	copyflag = 0;

	while ((skb1 = *skb_p) != NULL) {
		int ntail = 0;

		/* The fragment is partially pulled by someone,
		 * this can happen on input. Copy it and everything
		 * after it. */

		if (skb_shared(skb1))
			copyflag = 1;

		/* If the skb is the last, worry about trailer. */

		if (skb1->next == NULL && tailbits) {
			if (skb_shinfo(skb1)->nr_frags ||
			    skb_shinfo(skb1)->frag_list ||
			    skb_tailroom(skb1) < tailbits)
				ntail = tailbits + 128;
		}

		if (copyflag ||
		    skb_cloned(skb1) ||
		    ntail ||
		    skb_shinfo(skb1)->nr_frags ||
		    skb_shinfo(skb1)->frag_list) {
			struct sk_buff *skb2;

			/* Fuck, we are miserable poor guys... */
			if (ntail == 0)
				skb2 = skb_copy(skb1, GFP_ATOMIC);
			else
				skb2 = skb_copy_expand(skb1,
						       skb_headroom(skb1),
						       ntail,
						       GFP_ATOMIC);
			if (unlikely(skb2 == NULL))
				return -ENOMEM;

			if (skb1->sk)
				skb_set_owner_w(skb, skb1->sk);

			/* Looking around. Are we still alive?
			 * OK, link new skb, drop old one */

			skb2->next = skb1->next;
			*skb_p = skb2;
			kfree_skb(skb1);
			skb1 = skb2;
		}
		elt++;
		*trailer = skb1;
		skb_p = &skb1->next;
	}

	return elt;
}

/*
 *	Check if this packet is complete.
 *	Returns NULL on failure by any reason, and pointer
 *	to current nexthdr field in reassembled frame.
 *
 *	It is called with locked fq, and caller must check that
 *	queue is eligible for reassembly i.e. it is not COMPLETE,
 *	the last and the first frames arrived and all the bits are here.
 */
static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
			  struct net_device *dev)
{
	struct net *net = container_of(fq->q.net, struct net, ipv6.frags);
	struct sk_buff *fp, *head = fq->q.fragments;
	int    payload_len;
	unsigned int nhoff;

	fq_kill(fq);

	/* Make the one we just received the head. */
	if (prev) {
		head = prev->next;
		fp = skb_clone(head, GFP_ATOMIC);

		if (!fp)
			goto out_oom;

		fp->next = head->next;
		prev->next = fp;

		skb_morph(head, fq->q.fragments);
		head->next = fq->q.fragments->next;

		kfree_skb(fq->q.fragments);
		fq->q.fragments = head;
	}

	WARN_ON(head == NULL);
	WARN_ON(FRAG6_CB(head)->offset != 0);

	/* Unfragmented part is taken from the first segment. */
	payload_len = ((head->data - skb_network_header(head)) -
		       sizeof(struct ipv6hdr) + fq->q.len -
		       sizeof(struct frag_hdr));
	if (payload_len > IPV6_MAXPLEN)
		goto out_oversize;

	/* Head of list must not be cloned. */
	if (skb_cloned(head) && pskb_expand_head(head, 0, 0, GFP_ATOMIC))
		goto out_oom;

	/* If the first fragment is fragmented itself, we split
	 * it to two chunks: the first with data and paged part
	 * and the second, holding only fragments. */
	if (skb_shinfo(head)->frag_list) {
		struct sk_buff *clone;
		int i, plen = 0;

		if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
			goto out_oom;
		clone->next = head->next;
		head->next = clone;
		skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
		skb_shinfo(head)->frag_list = NULL;
		for (i=0; i<skb_shinfo(head)->nr_frags; i++)
			plen += skb_shinfo(head)->frags[i].size;
		clone->len = clone->data_len = head->data_len - plen;
		head->data_len -= clone->len;
		head->len -= clone->len;
		clone->csum = 0;
		clone->ip_summed = head->ip_summed;
		atomic_add(clone->truesize, &fq->q.net->mem);
	}

	/* We have to remove fragment header from datagram and to relocate
	 * header in order to calculate ICV correctly. */
	nhoff = fq->nhoffset;
	skb_network_header(head)[nhoff] = skb_transport_header(head)[0];
	memmove(head->head + sizeof(struct frag_hdr), head->head,
		(head->data - head->head) - sizeof(struct frag_hdr));
	head->mac_header += sizeof(struct frag_hdr);
	head->network_header += sizeof(struct frag_hdr);

	skb_shinfo(head)->frag_list = head->next;
	skb_reset_transport_header(head);
	skb_push(head, head->data - skb_network_header(head));
	atomic_sub(head->truesize, &fq->q.net->mem);

	for (fp=head->next; fp; fp = fp->next) {
		head->data_len += fp->len;
		head->len += fp->len;
		if (head->ip_summed != fp->ip_summed)
			head->ip_summed = CHECKSUM_NONE;
		else if (head->ip_summed == CHECKSUM_COMPLETE)
			head->csum = csum_add(head->csum, fp->csum);
		head->truesize += fp->truesize;
		atomic_sub(fp->truesize, &fq->q.net->mem);
	}

	head->next = NULL;
//.........这里部分代码省略.........