1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * Definitions for the IP protocol.
8 *
9 * Version: @(#)ip.h 1.0.2 04/28/93
10 *
11 * Authors: Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 */
13 #ifndef _LINUX_IP_H
14 #define _LINUX_IP_H
15
16 #include <linux/skbuff.h>
17 #include <uapi/linux/ip.h>
18
19 static inline struct iphdr *ip_hdr(const struct sk_buff *skb)
20 {
21 return (struct iphdr *)skb_network_header(skb);
22 }
23
24 static inline struct iphdr *inner_ip_hdr(const struct sk_buff *skb)
25 {
26 return (struct iphdr *)skb_inner_network_header(skb);
27 }
28
29 static inline struct iphdr *ipip_hdr(const struct sk_buff *skb)
30 {
31 return (struct iphdr *)skb_transport_header(skb);
32 }
33
34 static inline unsigned int ip_transport_len(const struct sk_buff *skb)
35 {
36 return ntohs(ip_hdr(skb)->tot_len) - skb_network_header_len(skb);
37 }
38
39 static inline unsigned int iph_totlen(const struct sk_buff *skb, const struct iphdr *iph)
40 {
41 u32 len = ntohs(iph->tot_len);
42
43 return (len || !skb_is_gso(skb) || !skb_is_gso_tcp(skb)) ?
44 len : skb->len - skb_network_offset(skb);
45 }
46
47 static inline unsigned int skb_ip_totlen(const struct sk_buff *skb)
48 {
49 return iph_totlen(skb, ip_hdr(skb));
50 }
51
52 /* IPv4 datagram length is stored into 16bit field (tot_len) */
53 #define IP_MAX_MTU 0xFFFFU
54
55 static inline void iph_set_totlen(struct iphdr *iph, unsigned int len)
56 {
57 iph->tot_len = len <= IP_MAX_MTU ? htons(len) : 0;
58 }
59 #endif /* _LINUX_IP_H */
60
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