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 * Checksumming functions for IPv6 7 * 8 * Authors: Jorge Cwik, <jorge@laser.satlink.net> 9 * Arnt Gulbrandsen, <agulbra@nvg.unit.no> 10 * Borrows very liberally from tcp.c and ip.c, see those 11 * files for more names. 12 * 13 * This program is free software; you can redistribute it and/or 14 * modify it under the terms of the GNU General Public License 15 * as published by the Free Software Foundation; either version 16 * 2 of the License, or (at your option) any later version. 17 */ 18 19 /* 20 * Fixes: 21 * 22 * Ralf Baechle : generic ipv6 checksum 23 * <ralf@waldorf-gmbh.de> 24 */ 25 26 #ifndef _CHECKSUM_IPV6_H 27 #define _CHECKSUM_IPV6_H 28 29 #include <asm/types.h> 30 #include <asm/byteorder.h> 31 #include <net/ip.h> 32 #include <asm/checksum.h> 33 #include <linux/in6.h> 34 #include <linux/tcp.h> 35 #include <linux/ipv6.h> 36 37 #ifndef _HAVE_ARCH_IPV6_CSUM 38 39 static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr, 40 const struct in6_addr *daddr, 41 __u32 len, unsigned short proto, 42 __wsum csum) 43 { 44 45 int carry; 46 __u32 ulen; 47 __u32 uproto; 48 __u32 sum = (__force u32)csum; 49 50 sum += (__force u32)saddr->s6_addr32[0]; 51 carry = (sum < (__force u32)saddr->s6_addr32[0]); 52 sum += carry; 53 54 sum += (__force u32)saddr->s6_addr32[1]; 55 carry = (sum < (__force u32)saddr->s6_addr32[1]); 56 sum += carry; 57 58 sum += (__force u32)saddr->s6_addr32[2]; 59 carry = (sum < (__force u32)saddr->s6_addr32[2]); 60 sum += carry; 61 62 sum += (__force u32)saddr->s6_addr32[3]; 63 carry = (sum < (__force u32)saddr->s6_addr32[3]); 64 sum += carry; 65 66 sum += (__force u32)daddr->s6_addr32[0]; 67 carry = (sum < (__force u32)daddr->s6_addr32[0]); 68 sum += carry; 69 70 sum += (__force u32)daddr->s6_addr32[1]; 71 carry = (sum < (__force u32)daddr->s6_addr32[1]); 72 sum += carry; 73 74 sum += (__force u32)daddr->s6_addr32[2]; 75 carry = (sum < (__force u32)daddr->s6_addr32[2]); 76 sum += carry; 77 78 sum += (__force u32)daddr->s6_addr32[3]; 79 carry = (sum < (__force u32)daddr->s6_addr32[3]); 80 sum += carry; 81 82 ulen = (__force u32)htonl((__u32) len); 83 sum += ulen; 84 carry = (sum < ulen); 85 sum += carry; 86 87 uproto = (__force u32)htonl(proto); 88 sum += uproto; 89 carry = (sum < uproto); 90 sum += carry; 91 92 return csum_fold((__force __wsum)sum); 93 } 94 95 #endif 96 97 static __inline__ __sum16 tcp_v6_check(int len, 98 const struct in6_addr *saddr, 99 const struct in6_addr *daddr, 100 __wsum base) 101 { 102 return csum_ipv6_magic(saddr, daddr, len, IPPROTO_TCP, base); 103 } 104 105 static inline void __tcp_v6_send_check(struct sk_buff *skb, 106 const struct in6_addr *saddr, 107 const struct in6_addr *daddr) 108 { 109 struct tcphdr *th = tcp_hdr(skb); 110 111 if (skb->ip_summed == CHECKSUM_PARTIAL) { 112 th->check = ~tcp_v6_check(skb->len, saddr, daddr, 0); 113 skb->csum_start = skb_transport_header(skb) - skb->head; 114 skb->csum_offset = offsetof(struct tcphdr, check); 115 } else { 116 th->check = tcp_v6_check(skb->len, saddr, daddr, 117 csum_partial(th, th->doff << 2, 118 skb->csum)); 119 } 120 } 121 122 static inline void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb) 123 { 124 struct ipv6_pinfo *np = inet6_sk(sk); 125 126 __tcp_v6_send_check(skb, &np->saddr, &np->daddr); 127 } 128 129 #endif 130