path: root/net/core/flow_dissector.c

#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/export.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/if_vlan.h>
#include <net/dsa.h>
#include <net/dst_metadata.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <net/gre.h>
#include <net/pptp.h>
#include <net/tipc.h>
#include <linux/igmp.h>
#include <linux/icmp.h>
#include <linux/sctp.h>
#include <linux/dccp.h>
#include <linux/if_tunnel.h>
#include <linux/if_pppox.h>
#include <linux/ppp_defs.h>
#include <linux/stddef.h>
#include <linux/if_ether.h>
#include <linux/mpls.h>
#include <linux/tcp.h>
#include <net/flow_dissector.h>
#include <scsi/fc/fc_fcoe.h>
#include <uapi/linux/batadv_packet.h>
#include <linux/bpf.h>

static DEFINE_MUTEX(flow_dissector_mutex);

static void dissector_set_key(struct flow_dissector *flow_dissector,
			      enum flow_dissector_key_id key_id)
{
	flow_dissector->used_keys |= (1 << key_id);
}

void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
			     const struct flow_dissector_key *key,
			     unsigned int key_count)
{
	unsigned int i;

	memset(flow_dissector, 0, sizeof(*flow_dissector));

	for (i = 0; i < key_count; i++, key++) {
		/* User should make sure that every key target offset is withing
		 * boundaries of unsigned short.
		 */
		BUG_ON(key->offset > USHRT_MAX);
		BUG_ON(dissector_uses_key(flow_dissector,
					  key->key_id));

		dissector_set_key(flow_dissector, key->key_id);
		flow_dissector->offset[key->key_id] = key->offset;
	}

	/* Ensure that the dissector always includes control and basic key.
	 * That way we are able to avoid handling lack of these in fast path.
	 */
	BUG_ON(!dissector_uses_key(flow_dissector,
				   FLOW_DISSECTOR_KEY_CONTROL));
	BUG_ON(!dissector_uses_key(flow_dissector,
				   FLOW_DISSECTOR_KEY_BASIC));
}
EXPORT_SYMBOL(skb_flow_dissector_init);

int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr,
				       struct bpf_prog *prog)
{
	struct bpf_prog *attached;
	struct net *net;

	net = current->nsproxy->net_ns;
	mutex_lock(&flow_dissector_mutex);
	attached = rcu_dereference_protected(net->flow_dissector_prog,
					     lockdep_is_held(&flow_dissector_mutex));
	if (attached) {
		/* Only one BPF program can be attached at a time */
		mutex_unlock(&flow_dissector_mutex);
		return -EEXIST;
	}
	rcu_assign_pointer(net->flow_dissector_prog, prog);
	mutex_unlock(&flow_dissector_mutex);
	return 0;
}

int skb_flow_dissector_bpf_prog_detach(const union bpf_attr *attr)
{
	struct bpf_prog *attached;
	struct net *net;

	net = current->nsproxy->net_ns;
	mutex_lock(&flow_dissector_mutex);
	attached = rcu_dereference_protected(net->flow_dissector_prog,
					     lockdep_is_held(&flow_dissector_mutex));
	if (!attached) {
		mutex_unlock(&flow_dissector_mutex);
		return -ENOENT;
	}
	bpf_prog_put(attached);
	RCU_INIT_POINTER(net->flow_dissector_prog, NULL);
	mutex_unlock(&flow_dissector_mutex);
	return 0;
}
/**
 * skb_flow_get_be16 - extract be16 entity
 * @skb: sk_buff to extract from
 * @poff: offset to extract at
 * @data: raw buffer pointer to the packet
 * @hlen: packet header length
 *
 * The function will try to retrieve a be32 entity at
 * offset poff
 */
static __be16 skb_flow_get_be16(const struct sk_buff *skb, int poff,
				void *data, int hlen)
{
	__be16 *u, _u;

	u = __skb_header_pointer(skb, poff, sizeof(_u), data, hlen, &_u);
	if (u)
		return *u;

	return 0;
}

/**
 * __skb_flow_get_ports - extract the upper layer ports and return them
 * @skb: sk_buff to extract the ports from
 * @thoff: transport header offset
 * @ip_proto: protocol for which to get port offset
 * @data: raw buffer pointer to the packet, if NULL use skb->data
 * @hlen: packet header length, if @data is NULL use skb_headlen(skb)
 *
 * The function will try to retrieve the ports at offset thoff + poff where poff
 * is the protocol port offset returned from proto_ports_offset
 */
__be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto,
			    void *data, int hlen)
{
	int poff = proto_ports_offset(ip_proto);

	if (!data) {
		data = skb->data;
		hlen = skb_headlen(skb);
	}

	if (poff >= 0) {
		__be32 *ports, _ports;

		ports = __skb_header_pointer(skb, thoff + poff,
					     sizeof(_ports), data, hlen, &_ports);
		if (ports)
			return *ports;
	}

	return 0;
}
EXPORT_SYMBOL(__skb_flow_get_ports);

static void
skb_flow_dissect_set_enc_addr_type(enum flow_dissector_key_id type,
				   struct flow_dissector *flow_dissector,
				   void *target_container)
{
	struct flow_dissector_key_control *ctrl;

	if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_CONTROL))
		return;

	ctrl = skb_flow_dissector_target(flow_dissector,
					 FLOW_DISSECTOR_KEY_ENC_CONTROL,
					 target_container);
	ctrl->addr_type =