include/net/gre.h

Source file repositories/reference/linux-study-clean/include/net/gre.h

File Facts

System
Linux kernel
Corpus path
include/net/gre.h
Extension
.h
Size
3883 bytes
Lines
148
Domain
Networking Core
Bucket
Sockets, Protocols, Packet Path, And Network Policy
Inferred role
Networking Core: implementation source
Status
source 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 gre_base_hdr {
	__be16 flags;
	__be16 protocol;
} __packed;

struct gre_full_hdr {
	struct gre_base_hdr fixed_header;
	__be16 csum;
	__be16 reserved1;
	__be32 key;
	__be32 seq;
} __packed;
#define GRE_HEADER_SECTION 4

#define GREPROTO_CISCO		0
#define GREPROTO_PPTP		1
#define GREPROTO_MAX		2
#define GRE_IP_PROTO_MAX	2

struct gre_protocol {
	int  (*handler)(struct sk_buff *skb);
	void (*err_handler)(struct sk_buff *skb, u32 info);
};

int gre_add_protocol(const struct gre_protocol *proto, u8 version);
int gre_del_protocol(const struct gre_protocol *proto, u8 version);

struct net_device *gretap_fb_dev_create(struct net *net, const char *name,
				       u8 name_assign_type);
int gre_parse_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
		     bool *csum_err, __be16 proto, int nhs);

static inline bool netif_is_gretap(const struct net_device *dev)
{
	return dev->rtnl_link_ops &&
	       !strcmp(dev->rtnl_link_ops->kind, "gretap");
}

static inline bool netif_is_ip6gretap(const struct net_device *dev)
{
	return dev->rtnl_link_ops &&
	       !strcmp(dev->rtnl_link_ops->kind, "ip6gretap");
}

static inline int gre_calc_hlen(const unsigned long *o_flags)
{
	int addend = 4;

	if (test_bit(IP_TUNNEL_CSUM_BIT, o_flags))
		addend += 4;
	if (test_bit(IP_TUNNEL_KEY_BIT, o_flags))
		addend += 4;
	if (test_bit(IP_TUNNEL_SEQ_BIT, o_flags))
		addend += 4;
	return addend;
}

static inline void gre_flags_to_tnl_flags(unsigned long *dst, __be16 flags)
{
	IP_TUNNEL_DECLARE_FLAGS(res) = { };

	__assign_bit(IP_TUNNEL_CSUM_BIT, res, flags & GRE_CSUM);
	__assign_bit(IP_TUNNEL_ROUTING_BIT, res, flags & GRE_ROUTING);
	__assign_bit(IP_TUNNEL_KEY_BIT, res, flags & GRE_KEY);
	__assign_bit(IP_TUNNEL_SEQ_BIT, res, flags & GRE_SEQ);
	__assign_bit(IP_TUNNEL_STRICT_BIT, res, flags & GRE_STRICT);
	__assign_bit(IP_TUNNEL_REC_BIT, res, flags & GRE_REC);
	__assign_bit(IP_TUNNEL_VERSION_BIT, res, flags & GRE_VERSION);

	ip_tunnel_flags_copy(dst, res);
}

static inline __be16 gre_tnl_flags_to_gre_flags(const unsigned long *tflags)
{
	__be16 flags = 0;

	if (test_bit(IP_TUNNEL_CSUM_BIT, tflags))
		flags |= GRE_CSUM;
	if (test_bit(IP_TUNNEL_ROUTING_BIT, tflags))
		flags |= GRE_ROUTING;
	if (test_bit(IP_TUNNEL_KEY_BIT, tflags))
		flags |= GRE_KEY;
	if (test_bit(IP_TUNNEL_SEQ_BIT, tflags))
		flags |= GRE_SEQ;
	if (test_bit(IP_TUNNEL_STRICT_BIT, tflags))
		flags |= GRE_STRICT;
	if (test_bit(IP_TUNNEL_REC_BIT, tflags))
		flags |= GRE_REC;
	if (test_bit(IP_TUNNEL_VERSION_BIT, tflags))
		flags |= GRE_VERSION;

Annotation

Implementation Notes