C++ skb_tail_pointer函数代码示例

static int tcf_nat_dump(struct sk_buff *skb, struct tc_action *a,
			int bind, int ref)
{
	unsigned char *b = skb_tail_pointer(skb);
	struct tcf_nat *p = a->priv;
	struct tc_nat *opt;
	struct tcf_t t;
	int s;

	s = sizeof(*opt);

	/* netlink spinlocks held above us - must use ATOMIC */
	opt = kzalloc(s, GFP_ATOMIC);
	if (unlikely(!opt))
		return -ENOBUFS;

	opt->old_addr = p->old_addr;
	opt->new_addr = p->new_addr;
	opt->mask = p->mask;
	opt->flags = p->flags;

	opt->index = p->tcf_index;
	opt->action = p->tcf_action;
	opt->refcnt = p->tcf_refcnt - ref;
	opt->bindcnt = p->tcf_bindcnt - bind;

	RTA_PUT(skb, TCA_NAT_PARMS, s, opt);
	t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);
	t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);
	t.expires = jiffies_to_clock_t(p->tcf_tm.expires);
	RTA_PUT(skb, TCA_NAT_TM, sizeof(t), &t);

	kfree(opt);

	return skb->len;

rtattr_failure:
	nlmsg_trim(skb, b);
	kfree(opt);
	return -1;
}

static int __if_usb_submit_rx_urb(struct if_usb_card *cardp,
				  void (*callbackfn)(struct urb *urb))
{
	struct sk_buff *skb;
	int ret = -1;

	lbtf_deb_enter(LBTF_DEB_USB);

	skb = dev_alloc_skb(MRVDRV_ETH_RX_PACKET_BUFFER_SIZE);
	if (!skb) {
		pr_err("No free skb\n");
		lbtf_deb_leave(LBTF_DEB_USB);
		return -1;
	}

	cardp->rx_skb = skb;

	/* Fill the receive configuration URB and initialise the Rx call back */
	usb_fill_bulk_urb(cardp->rx_urb, cardp->udev,
			  usb_rcvbulkpipe(cardp->udev, cardp->ep_in),
			  skb_tail_pointer(skb),
			  MRVDRV_ETH_RX_PACKET_BUFFER_SIZE, callbackfn, cardp);

	cardp->rx_urb->transfer_flags |= URB_ZERO_PACKET;

	lbtf_deb_usb2(&cardp->udev->dev, "Pointer for rx_urb %p\n",
		cardp->rx_urb);
	ret = usb_submit_urb(cardp->rx_urb, GFP_ATOMIC);
	if (ret) {
		lbtf_deb_usbd(&cardp->udev->dev,
			"Submit Rx URB failed: %d\n", ret);
		kfree_skb(skb);
		cardp->rx_skb = NULL;
		lbtf_deb_leave(LBTF_DEB_USB);
		return -1;
	} else {
		lbtf_deb_usb2(&cardp->udev->dev, "Submit Rx URB success\n");
		lbtf_deb_leave(LBTF_DEB_USB);
		return 0;
	}
}

struct cfpkt *cfpkt_append(struct cfpkt *dstpkt,
			     struct cfpkt *addpkt,
			     u16 expectlen)
{
	struct sk_buff *dst = pkt_to_skb(dstpkt);
	struct sk_buff *add = pkt_to_skb(addpkt);
	u16 addlen = skb_headlen(add);
	u16 neededtailspace;
	struct sk_buff *tmp;
	u16 dstlen;
	u16 createlen;
	if (unlikely(is_erronous(dstpkt) || is_erronous(addpkt))) {
		cfpkt_destroy(addpkt);
		return dstpkt;
	}
	if (expectlen > addlen)
		neededtailspace = expectlen;
	else
		neededtailspace = addlen;

	if (dst->tail + neededtailspace > dst->end) {
		/* Create a dumplicate of 'dst' with more tail space */
		struct cfpkt *tmppkt;
		dstlen = skb_headlen(dst);
		createlen = dstlen + neededtailspace;
		tmppkt = cfpkt_create(createlen + PKT_PREFIX + PKT_POSTFIX);
		if (tmppkt == NULL)
			return NULL;
		tmp = pkt_to_skb(tmppkt);
		skb_set_tail_pointer(tmp, dstlen);
		tmp->len = dstlen;
		memcpy(tmp->data, dst->data, dstlen);
		cfpkt_destroy(dstpkt);
		dst = tmp;
	}
	memcpy(skb_tail_pointer(dst), add->data, skb_headlen(add));
	cfpkt_destroy(addpkt);
	dst->tail += addlen;
	dst->len += addlen;
	return skb_to_pkt(dst);
}

static int tcf_bpf_dump(struct sk_buff *skb, struct tc_action *act,
			int bind, int ref)
{
	unsigned char *tp = skb_tail_pointer(skb);
	struct tcf_bpf *prog = to_bpf(act);
	struct tc_act_bpf opt = {
		.index   = prog->tcf_index,
		.refcnt  = refcount_read(&prog->tcf_refcnt) - ref,
		.bindcnt = atomic_read(&prog->tcf_bindcnt) - bind,
	};
	struct tcf_t tm;
	int ret;

	spin_lock_bh(&prog->tcf_lock);
	opt.action = prog->tcf_action;
	if (nla_put(skb, TCA_ACT_BPF_PARMS, sizeof(opt), &opt))
		goto nla_put_failure;

	if (tcf_bpf_is_ebpf(prog))
		ret = tcf_bpf_dump_ebpf_info(prog, skb);
	else
		ret = tcf_bpf_dump_bpf_info(prog, skb);
	if (ret)
		goto nla_put_failure;

	tcf_tm_dump(&tm, &prog->tcf_tm);
	if (nla_put_64bit(skb, TCA_ACT_BPF_TM, sizeof(tm), &tm,
			  TCA_ACT_BPF_PAD))
		goto nla_put_failure;

	spin_unlock_bh(&prog->tcf_lock);
	return skb->len;

nla_put_failure:
	spin_unlock_bh(&prog->tcf_lock);
	nlmsg_trim(skb, tp);
	return -1;
}

static const struct nla_policy act_bpf_policy[TCA_ACT_BPF_MAX + 1] = {
	[TCA_ACT_BPF_PARMS]	= { .len = sizeof(struct tc_act_bpf) },

static void p54p_refill_rx_ring(struct ieee80211_hw *dev)
{
    struct p54p_priv *priv = dev->priv;
    struct p54p_ring_control *ring_control = priv->ring_control;
    u32 limit, host_idx, idx;

    host_idx = le32_to_cpu(ring_control->host_idx[0]);
    limit = host_idx;
    limit -= le32_to_cpu(ring_control->device_idx[0]);
    limit = ARRAY_SIZE(ring_control->rx_data) - limit;

    idx = host_idx % ARRAY_SIZE(ring_control->rx_data);
    while (limit-- > 1) {
        struct p54p_desc *desc = &ring_control->rx_data[idx];

        if (!desc->host_addr) {
            struct sk_buff *skb;
            dma_addr_t mapping;
            skb = dev_alloc_skb(MAX_RX_SIZE);
            if (!skb)
                break;

            mapping = pci_map_single(priv->pdev,
                         skb_tail_pointer(skb),
                         MAX_RX_SIZE,
                         PCI_DMA_FROMDEVICE);
            desc->host_addr = cpu_to_le32(mapping);
            desc->device_addr = 0;    // FIXME: necessary?
            desc->len = cpu_to_le16(MAX_RX_SIZE);
            desc->flags = 0;
            priv->rx_buf[idx] = skb;
        }

        idx++;
        host_idx++;
        idx %= ARRAY_SIZE(ring_control->rx_data);
    }

    wmb();
    ring_control->host_idx[0] = cpu_to_le32(host_idx);
}

static int sfq_dump(struct Qdisc *sch, struct sk_buff *skb)
{
	struct sfq_sched_data *q = qdisc_priv(sch);
	unsigned char *b = skb_tail_pointer(skb);
	struct tc_sfq_qopt opt;

	opt.quantum = q->quantum;
	opt.perturb_period = q->perturb_period;
	opt.limit = q->limit;
	opt.divisor = q->hash_divisor;
	opt.flows = q->depth;
	opt.hash_kind = q->hash_kind;

	RTA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);

	return skb->len;

rtattr_failure:
	nlmsg_trim(skb, b);
	return -1;
}

static int sfq_dump(struct Qdisc *sch, struct sk_buff *skb)
{
	struct sfq_sched_data *q = qdisc_priv(sch);
	unsigned char *b = skb_tail_pointer(skb);
	struct tc_sfq_qopt opt;

	opt.quantum = q->quantum;
	opt.perturb_period = q->perturb_period / HZ;

	opt.limit = q->limit;
	opt.divisor = SFQ_HASH_DIVISOR;
	opt.flows = q->limit;

	NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);

	return skb->len;

nla_put_failure:
	nlmsg_trim(skb, b);
	return -1;
}

static int tcf_bpf_dump(struct sk_buff *skb, struct tc_action *act,
			int bind, int ref)
{
	unsigned char *tp = skb_tail_pointer(skb);
	struct tcf_bpf *prog = act->priv;
	struct tc_act_bpf opt = {
		.index   = prog->tcf_index,
		.refcnt  = prog->tcf_refcnt - ref,
		.bindcnt = prog->tcf_bindcnt - bind,
		.action  = prog->tcf_action,
	};
	struct tcf_t tm;
	int ret;

	if (nla_put(skb, TCA_ACT_BPF_PARMS, sizeof(opt), &opt))
		goto nla_put_failure;

	if (tcf_bpf_is_ebpf(prog))
		ret = tcf_bpf_dump_ebpf_info(prog, skb);
	else
		ret = tcf_bpf_dump_bpf_info(prog, skb);
	if (ret)
		goto nla_put_failure;

	tm.install = jiffies_to_clock_t(jiffies - prog->tcf_tm.install);
	tm.lastuse = jiffies_to_clock_t(jiffies - prog->tcf_tm.lastuse);
	tm.expires = jiffies_to_clock_t(prog->tcf_tm.expires);

	if (nla_put(skb, TCA_ACT_BPF_TM, sizeof(tm), &tm))
		goto nla_put_failure;

	return skb->len;

nla_put_failure:
	nlmsg_trim(skb, tp);
	return -1;
}

static const struct nla_policy act_bpf_policy[TCA_ACT_BPF_MAX + 1] = {
	[TCA_ACT_BPF_PARMS]	= { .len = sizeof(struct tc_act_bpf) },

int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
{
	u16 offset = sizeof(struct ipv6hdr);
	struct ipv6_opt_hdr *exthdr =
				(struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
	unsigned int packet_len = skb_tail_pointer(skb) -
		skb_network_header(skb);
	int found_rhdr = 0;
	*nexthdr = &ipv6_hdr(skb)->nexthdr;

	while (offset + 1 <= packet_len) {

		switch (**nexthdr) {

		case NEXTHDR_HOP:
			break;
		case NEXTHDR_ROUTING:
			found_rhdr = 1;
			break;
		case NEXTHDR_DEST:
#if IS_ENABLED(CONFIG_IPV6_MIP6)
			if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
				break;
#endif
			if (found_rhdr)
				return offset;
			break;
		default :
			return offset;
		}

		offset += ipv6_optlen(exthdr);
		*nexthdr = &exthdr->nexthdr;
		exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
						 offset);
	}

	return offset;
}

static void p54u_rx_cb(struct urb *urb)
{
	struct sk_buff *skb = (struct sk_buff *) urb->context;
	struct p54u_rx_info *info = (struct p54u_rx_info *)skb->cb;
	struct ieee80211_hw *dev = info->dev;
	struct p54u_priv *priv = dev->priv;

	if (unlikely(urb->status)) {
		info->urb = NULL;
		usb_free_urb(urb);
		return;
	}

	skb_unlink(skb, &priv->rx_queue);
	skb_put(skb, urb->actual_length);
	if (!priv->hw_type)
		skb_pull(skb, sizeof(struct net2280_tx_hdr));

	if (p54_rx(dev, skb)) {
		skb = dev_alloc_skb(MAX_RX_SIZE);
		if (unlikely(!skb)) {
			usb_free_urb(urb);
			/* TODO check rx queue length and refill *somewhere* */
			return;
		}

		info = (struct p54u_rx_info *) skb->cb;
		info->urb = urb;
		info->dev = dev;
		urb->transfer_buffer = skb_tail_pointer(skb);
		urb->context = skb;
		skb_queue_tail(&priv->rx_queue, skb);
	} else {
		skb_trim(skb, 0);
		skb_queue_tail(&priv->rx_queue, skb);
	}

	usb_submit_urb(urb, GFP_ATOMIC);
}

void ipv6_local_rxpmtu(struct sock *sk, struct flowi6 *fl6, u32 mtu)
{
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct ipv6hdr *iph;
	struct sk_buff *skb;
	struct ip6_mtuinfo *mtu_info;

	if (!np->rxopt.bits.rxpmtu)
		return;

	skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
	if (!skb)
		return;

	skb_put(skb, sizeof(struct ipv6hdr));
	skb_reset_network_header(skb);
	iph = ipv6_hdr(skb);
	ipv6_addr_copy(&iph->daddr, &fl6->daddr);

	mtu_info = IP6CBMTU(skb);
	if (!mtu_info) {
		kfree_skb(skb);
		return;
	}

	mtu_info->ip6m_mtu = mtu;
	mtu_info->ip6m_addr.sin6_family = AF_INET6;
	mtu_info->ip6m_addr.sin6_port = 0;
	mtu_info->ip6m_addr.sin6_flowinfo = 0;
	mtu_info->ip6m_addr.sin6_scope_id = fl6->flowi6_oif;
	ipv6_addr_copy(&mtu_info->ip6m_addr.sin6_addr, &ipv6_hdr(skb)->daddr);

	__skb_pull(skb, skb_tail_pointer(skb) - skb->data);
	skb_reset_transport_header(skb);

	skb = xchg(&np->rxpmtu, skb);
	kfree_skb(skb);
}

void ipv6_local_error(struct sock *sk, int err, struct flowi6 *fl6, u32 info)
{
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct sock_exterr_skb *serr;
	struct ipv6hdr *iph;
	struct sk_buff *skb;

	if (!np->recverr)
		return;

	skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
	if (!skb)
		return;

	skb->protocol = htons(ETH_P_IPV6);

	skb_put(skb, sizeof(struct ipv6hdr));
	skb_reset_network_header(skb);
	iph = ipv6_hdr(skb);
	iph->daddr = fl6->daddr;

	serr = SKB_EXT_ERR(skb);
	serr->ee.ee_errno = err;
	serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
	serr->ee.ee_type = 0;
	serr->ee.ee_code = 0;
	serr->ee.ee_pad = 0;
	serr->ee.ee_info = info;
	serr->ee.ee_data = 0;
	serr->addr_offset = (u8 *)&iph->daddr - skb_network_header(skb);
	serr->port = fl6->fl6_dport;

	__skb_pull(skb, skb_tail_pointer(skb) - skb->data);
	skb_reset_transport_header(skb);

	if (sock_queue_err_skb(sk, skb))
		kfree_skb(skb);
}

static int prio_dump(struct Qdisc *sch, struct sk_buff *skb)
{
	struct prio_sched_data *q = qdisc_priv(sch);
	unsigned char *b = skb_tail_pointer(skb);
	struct tc_prio_qopt opt;
	int err;

	opt.bands = q->bands;
	memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX + 1);

	err = prio_dump_offload(sch);
	if (err)
		goto nla_put_failure;

	if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
		goto nla_put_failure;

	return skb->len;

nla_put_failure:
	nlmsg_trim(skb, b);
	return -1;
}

/**
 * gnet_stats_finish_copy - finish dumping procedure
 * @d: dumping handle
 *
 * Corrects the length of the top level TLV to include all TLVs added
 * by gnet_stats_copy_XXX() calls. Adds the backward compatibility TLVs
 * if gnet_stats_start_copy_compat() was used and releases the statistics
 * lock.
 *
 * Returns 0 on success or -1 with the statistic lock released
 * if the room in the socket buffer was not sufficient.
 */
int
gnet_stats_finish_copy(struct gnet_dump *d)
{
    if (d->tail)
        d->tail->nla_len = skb_tail_pointer(d->skb) - (u8 *)d->tail;

    if (d->compat_tc_stats)
        if (gnet_stats_copy(d, d->compat_tc_stats, &d->tc_stats,
                            sizeof(d->tc_stats)) < 0)
            return -1;

    if (d->compat_xstats && d->xstats) {
        if (gnet_stats_copy(d, d->compat_xstats, d->xstats,
                            d->xstats_len) < 0)
            return -1;
    }

    kfree(d->xstats);
    d->xstats = NULL;
    d->xstats_len = 0;
    spin_unlock_bh(d->lock);
    return 0;
}

void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 port, u32 info)
{
	struct inet_sock *inet = inet_sk(sk);
	struct sock_exterr_skb *serr;
	struct iphdr *iph;
	struct sk_buff *skb;

	if (!inet->recverr)
		return;

	skb = alloc_skb(sizeof(struct iphdr), GFP_ATOMIC);
	if (!skb)
		return;

	skb_put(skb, sizeof(struct iphdr));
	skb_reset_network_header(skb);
	iph = ip_hdr(skb);
	iph->daddr = daddr;

	serr = SKB_EXT_ERR(skb);
	serr->ee.ee_errno = err;
	serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
	serr->ee.ee_type = 0;
	serr->ee.ee_code = 0;
	serr->ee.ee_pad = 0;
	serr->ee.ee_info = info;
	serr->ee.ee_data = 0;
	serr->addr_offset = (u8 *)&iph->daddr - skb_network_header(skb);
	serr->port = port;

	__skb_pull(skb, skb_tail_pointer(skb) - skb->data);
	skb_reset_transport_header(skb);

	if (sock_queue_err_skb(sk, skb))
		kfree_skb(skb);
}