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 IP protocol.
7  *
8  * Version:	@(#)ip.h	1.0.2	04/28/93
9  *
10  * Authors:	Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
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_IP_H
18 #define _LINUX_IP_H
19 #include <asm/byteorder.h>
20 
21 /* SOL_IP socket options */
22 
23 #define IPTOS_TOS_MASK		0x1E
24 #define IPTOS_TOS(tos)		((tos)&IPTOS_TOS_MASK)
25 #define	IPTOS_LOWDELAY		0x10
26 #define	IPTOS_THROUGHPUT	0x08
27 #define	IPTOS_RELIABILITY	0x04
28 #define	IPTOS_MINCOST		0x02
29 
30 #define IPTOS_PREC_MASK		0xE0
31 #define IPTOS_PREC(tos)		((tos)&IPTOS_PREC_MASK)
32 #define IPTOS_PREC_NETCONTROL           0xe0
33 #define IPTOS_PREC_INTERNETCONTROL      0xc0
34 #define IPTOS_PREC_CRITIC_ECP           0xa0
35 #define IPTOS_PREC_FLASHOVERRIDE        0x80
36 #define IPTOS_PREC_FLASH                0x60
37 #define IPTOS_PREC_IMMEDIATE            0x40
38 #define IPTOS_PREC_PRIORITY             0x20
39 #define IPTOS_PREC_ROUTINE              0x00
40 
41 
42 /* IP options */
43 #define IPOPT_COPY		0x80
44 #define IPOPT_CLASS_MASK	0x60
45 #define IPOPT_NUMBER_MASK	0x1f
46 
47 #define	IPOPT_COPIED(o)		((o)&IPOPT_COPY)
48 #define	IPOPT_CLASS(o)		((o)&IPOPT_CLASS_MASK)
49 #define	IPOPT_NUMBER(o)		((o)&IPOPT_NUMBER_MASK)
50 
51 #define	IPOPT_CONTROL		0x00
52 #define	IPOPT_RESERVED1		0x20
53 #define	IPOPT_MEASUREMENT	0x40
54 #define	IPOPT_RESERVED2		0x60
55 
56 #define IPOPT_END	(0 |IPOPT_CONTROL)
57 #define IPOPT_NOOP	(1 |IPOPT_CONTROL)
58 #define IPOPT_SEC	(2 |IPOPT_CONTROL|IPOPT_COPY)
59 #define IPOPT_LSRR	(3 |IPOPT_CONTROL|IPOPT_COPY)
60 #define IPOPT_TIMESTAMP	(4 |IPOPT_MEASUREMENT)
61 #define IPOPT_RR	(7 |IPOPT_CONTROL)
62 #define IPOPT_SID	(8 |IPOPT_CONTROL|IPOPT_COPY)
63 #define IPOPT_SSRR	(9 |IPOPT_CONTROL|IPOPT_COPY)
64 #define IPOPT_RA	(20|IPOPT_CONTROL|IPOPT_COPY)
65 
66 #define IPVERSION	4
67 #define MAXTTL		255
68 #define IPDEFTTL	64
69 
70 /* struct timestamp, struct route and MAX_ROUTES are removed.
71 
72    REASONS: it is clear that nobody used them because:
73    - MAX_ROUTES value was wrong.
74    - "struct route" was wrong.
75    - "struct timestamp" had fatally misaligned bitfields and was completely unusable.
76  */
77 
78 #define IPOPT_OPTVAL 0
79 #define IPOPT_OLEN   1
80 #define IPOPT_OFFSET 2
81 #define IPOPT_MINOFF 4
82 #define MAX_IPOPTLEN 40
83 #define IPOPT_NOP IPOPT_NOOP
84 #define IPOPT_EOL IPOPT_END
85 #define IPOPT_TS  IPOPT_TIMESTAMP
86 
87 #define	IPOPT_TS_TSONLY		0		/* timestamps only */
88 #define	IPOPT_TS_TSANDADDR	1		/* timestamps and addresses */
89 #define	IPOPT_TS_PRESPEC	3		/* specified modules only */
90 
91 #ifdef __KERNEL__
92 
93 struct ip_options {
94   __u32		faddr;				/* Saved first hop address */
95   unsigned char	optlen;
96   unsigned char srr;
97   unsigned char rr;
98   unsigned char ts;
99   unsigned char is_setbyuser:1,			/* Set by setsockopt?			*/
100                 is_data:1,			/* Options in __data, rather than skb	*/
101                 is_strictroute:1,		/* Strict source route			*/
102                 srr_is_hit:1,			/* Packet destination addr was our one	*/
103                 is_changed:1,			/* IP checksum more not valid		*/
104                 rr_needaddr:1,			/* Need to record addr of outgoing dev	*/
105                 ts_needtime:1,			/* Need to record timestamp		*/
106                 ts_needaddr:1;			/* Need to record addr of outgoing dev  */
107   unsigned char router_alert;
108   unsigned char __pad1;
109   unsigned char __pad2;
110   unsigned char __data[0];
111 };
112 
113 #define optlength(opt) (sizeof(struct ip_options) + opt->optlen)
114 #endif
115 
116 struct iphdr {
117 #if defined(__LITTLE_ENDIAN_BITFIELD)
118 	__u8	ihl:4,
119 		version:4;
120 #elif defined (__BIG_ENDIAN_BITFIELD)
121 	__u8	version:4,
122   		ihl:4;
123 #else
124 #error	"Please fix <asm/byteorder.h>"
125 #endif
126 	__u8	tos;
127 	__u16	tot_len;
128 	__u16	id;
129 	__u16	frag_off;
130 	__u8	ttl;
131 	__u8	protocol;
132 	__u16	check;
133 	__u32	saddr;
134 	__u32	daddr;
135 	/*The options start here. */
136 };
137 
138 #endif	/* _LINUX_IP_H */
139