xref: /linux-6.15/include/linux/udp.h (revision eb2bce7f)
1 /*
2  * INET		An implementation of the TCP/IP protocol suite for the LINUX
3  *		operating system.  INET is implemented using the  BSD Socket
4  *		interface as the means of communication with the user level.
5  *
6  *		Definitions for the UDP protocol.
7  *
8  * Version:	@(#)udp.h	1.0.2	04/28/93
9  *
10  * Author:	Fred N. van Kempen, <[email protected]>
11  *
12  *		This program is free software; you can redistribute it and/or
13  *		modify it under the terms of the GNU General Public License
14  *		as published by the Free Software Foundation; either version
15  *		2 of the License, or (at your option) any later version.
16  */
17 #ifndef _LINUX_UDP_H
18 #define _LINUX_UDP_H
19 
20 #include <linux/types.h>
21 
22 struct udphdr {
23 	__be16	source;
24 	__be16	dest;
25 	__be16	len;
26 	__sum16	check;
27 };
28 
29 #ifdef __KERNEL__
30 #include <linux/skbuff.h>
31 
32 static inline struct udphdr *udp_hdr(const struct sk_buff *skb)
33 {
34 	return (struct udphdr *)skb_transport_header(skb);
35 }
36 #endif
37 
38 /* UDP socket options */
39 #define UDP_CORK	1	/* Never send partially complete segments */
40 #define UDP_ENCAP	100	/* Set the socket to accept encapsulated packets */
41 
42 /* UDP encapsulation types */
43 #define UDP_ENCAP_ESPINUDP_NON_IKE	1 /* draft-ietf-ipsec-nat-t-ike-00/01 */
44 #define UDP_ENCAP_ESPINUDP	2 /* draft-ietf-ipsec-udp-encaps-06 */
45 
46 #ifdef __KERNEL__
47 #include <linux/types.h>
48 
49 #include <net/inet_sock.h>
50 #define UDP_HTABLE_SIZE		128
51 
52 struct udp_sock {
53 	/* inet_sock has to be the first member */
54 	struct inet_sock inet;
55 	int		 pending;	/* Any pending frames ? */
56 	unsigned int	 corkflag;	/* Cork is required */
57   	__u16		 encap_type;	/* Is this an Encapsulation socket? */
58 	/*
59 	 * Following member retains the information to create a UDP header
60 	 * when the socket is uncorked.
61 	 */
62 	__u16		 len;		/* total length of pending frames */
63 	/*
64 	 * Fields specific to UDP-Lite.
65 	 */
66 	__u16		 pcslen;
67 	__u16		 pcrlen;
68 /* indicator bits used by pcflag: */
69 #define UDPLITE_BIT      0x1  		/* set by udplite proto init function */
70 #define UDPLITE_SEND_CC  0x2  		/* set via udplite setsockopt         */
71 #define UDPLITE_RECV_CC  0x4		/* set via udplite setsocktopt        */
72 	__u8		 pcflag;        /* marks socket as UDP-Lite if > 0    */
73 };
74 
75 static inline struct udp_sock *udp_sk(const struct sock *sk)
76 {
77 	return (struct udp_sock *)sk;
78 }
79 #define IS_UDPLITE(__sk) (udp_sk(__sk)->pcflag)
80 
81 #endif
82 
83 #endif	/* _LINUX_UDP_H */
84