net/netfilter/nf_queue.c

Source file repositories/reference/linux-study-clean/net/netfilter/nf_queue.c

File Facts

System
Linux kernel
Corpus path
net/netfilter/nf_queue.c
Extension
.c
Size
5814 bytes
Lines
254
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

if (!sk_is_refcounted(sk)) {
			if (!refcount_inc_not_zero(&sk->sk_refcnt))
				return -ENOTCONN;

			/* drop refcount on skb_orphan */
			skb->destructor = sock_edemux;
		}
	}

	entry = kmalloc(sizeof(*entry) + route_key_size, GFP_ATOMIC);
	if (!entry)
		return -ENOMEM;

	if (skb_dst(skb) && !skb_dst_force(skb)) {
		kfree(entry);
		return -ENETDOWN;
	}

	*entry = (struct nf_queue_entry) {
		.skb	= skb,
		.skb_dev = skb->dev,
		.state	= *state,
		.hook_index = index,
		.size	= sizeof(*entry) + route_key_size,
	};
	__nf_queue_entry_init_physdevs(entry);

	if (!nf_queue_entry_get_refs(entry)) {
		kfree(entry);
		return -ENOTCONN;
	}

	switch (entry->state.pf) {
	case AF_INET:
		nf_ip_saveroute(skb, entry);
		break;
	case AF_INET6:
		nf_ip6_saveroute(skb, entry);
		break;
	}

	status = qh->outfn(entry, queuenum);
	if (status < 0) {
		nf_queue_entry_free(entry);
		return status;
	}

	return 0;
}

/* Packets leaving via this function must come back through nf_reinject(). */
int nf_queue(struct sk_buff *skb, struct nf_hook_state *state,
	     unsigned int index, unsigned int verdict)
{
	int ret;

	ret = __nf_queue(skb, state, index, verdict >> NF_VERDICT_QBITS);
	if (ret < 0) {
		if (ret == -ESRCH &&
		    (verdict & NF_VERDICT_FLAG_QUEUE_BYPASS))
			return 1;
		kfree_skb(skb);
	}

	return 0;
}
EXPORT_SYMBOL_GPL(nf_queue);

Annotation

Implementation Notes