net/sched/sch_frag.c

Source file repositories/reference/linux-study-clean/net/sched/sch_frag.c

File Facts

System
Linux kernel
Corpus path
net/sched/sch_frag.c
Extension
.c
Size
4254 bytes
Lines
161
Domain
Networking Core
Bucket
Sockets, Protocols, Packet Path, And Network Policy
Inferred role
Networking Core: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Networking stack implementation surface: socket APIs, protocol dispatch, packet flow, routing, filtering, and network namespaces.

Dependency Surface

Detected Declarations

Annotated Snippet

struct sch_frag_data {
	unsigned long dst;
	struct qdisc_skb_cb cb;
	__be16 inner_protocol;
	u16 vlan_tci;
	__be16 vlan_proto;
	unsigned int l2_len;
	u8 l2_data[VLAN_ETH_HLEN];
	int (*xmit)(struct sk_buff *skb);
	local_lock_t bh_lock;
};

static DEFINE_PER_CPU(struct sch_frag_data, sch_frag_data_storage) = {
	.bh_lock = INIT_LOCAL_LOCK(bh_lock),
};

static int sch_frag_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	struct sch_frag_data *data = this_cpu_ptr(&sch_frag_data_storage);

	lockdep_assert_held(&data->bh_lock);
	if (skb_cow_head(skb, data->l2_len) < 0) {
		kfree_skb(skb);
		return -ENOMEM;
	}

	__skb_dst_copy(skb, data->dst);
	*qdisc_skb_cb(skb) = data->cb;
	skb->inner_protocol = data->inner_protocol;
	if (data->vlan_tci & VLAN_CFI_MASK)
		__vlan_hwaccel_put_tag(skb, data->vlan_proto,
				       data->vlan_tci & ~VLAN_CFI_MASK);
	else
		__vlan_hwaccel_clear_tag(skb);

	/* Reconstruct the MAC header.  */
	skb_push(skb, data->l2_len);
	memcpy(skb->data, &data->l2_data, data->l2_len);
	skb_postpush_rcsum(skb, skb->data, data->l2_len);
	skb_reset_mac_header(skb);

	return data->xmit(skb);
}

static void sch_frag_prepare_frag(struct sk_buff *skb,
				  int (*xmit)(struct sk_buff *skb))
{
	unsigned int hlen = skb_network_offset(skb);
	struct sch_frag_data *data;

	data = this_cpu_ptr(&sch_frag_data_storage);
	data->dst = skb->_skb_refdst;
	data->cb = *qdisc_skb_cb(skb);
	data->xmit = xmit;
	data->inner_protocol = skb->inner_protocol;
	if (skb_vlan_tag_present(skb))
		data->vlan_tci = skb_vlan_tag_get(skb) | VLAN_CFI_MASK;
	else
		data->vlan_tci = 0;
	data->vlan_proto = skb->vlan_proto;
	data->l2_len = hlen;
	memcpy(&data->l2_data, skb->data, hlen);

	memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
	skb_pull(skb, hlen);
}

static unsigned int
sch_frag_dst_get_mtu(const struct dst_entry *dst)
{
	return dst->dev->mtu;
}

static struct dst_ops sch_frag_dst_ops = {
	.family = AF_UNSPEC,
	.mtu = sch_frag_dst_get_mtu,
};

static int sch_fragment(struct net *net, struct sk_buff *skb,
			u16 mru, int (*xmit)(struct sk_buff *skb))
{
	int ret = -1;

	if (skb_network_offset(skb) > VLAN_ETH_HLEN) {
		net_warn_ratelimited("L2 header too long to fragment\n");
		goto err;
	}

	if (skb_protocol(skb, true) == htons(ETH_P_IP)) {
		struct rtable sch_frag_rt = { 0 };

Annotation

Implementation Notes