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