1 #ifndef _INET_ECN_H_ 2 #define _INET_ECN_H_ 3 4 #include <linux/ip.h> 5 #include <linux/skbuff.h> 6 7 #include <net/inet_sock.h> 8 #include <net/dsfield.h> 9 10 enum { 11 INET_ECN_NOT_ECT = 0, 12 INET_ECN_ECT_1 = 1, 13 INET_ECN_ECT_0 = 2, 14 INET_ECN_CE = 3, 15 INET_ECN_MASK = 3, 16 }; 17 18 static inline int INET_ECN_is_ce(__u8 dsfield) 19 { 20 return (dsfield & INET_ECN_MASK) == INET_ECN_CE; 21 } 22 23 static inline int INET_ECN_is_not_ect(__u8 dsfield) 24 { 25 return (dsfield & INET_ECN_MASK) == INET_ECN_NOT_ECT; 26 } 27 28 static inline int INET_ECN_is_capable(__u8 dsfield) 29 { 30 return dsfield & INET_ECN_ECT_0; 31 } 32 33 /* 34 * RFC 3168 9.1.1 35 * The full-functionality option for ECN encapsulation is to copy the 36 * ECN codepoint of the inside header to the outside header on 37 * encapsulation if the inside header is not-ECT or ECT, and to set the 38 * ECN codepoint of the outside header to ECT(0) if the ECN codepoint of 39 * the inside header is CE. 40 */ 41 static inline __u8 INET_ECN_encapsulate(__u8 outer, __u8 inner) 42 { 43 outer &= ~INET_ECN_MASK; 44 outer |= !INET_ECN_is_ce(inner) ? (inner & INET_ECN_MASK) : 45 INET_ECN_ECT_0; 46 return outer; 47 } 48 49 static inline void INET_ECN_xmit(struct sock *sk) 50 { 51 inet_sk(sk)->tos |= INET_ECN_ECT_0; 52 if (inet6_sk(sk) != NULL) 53 inet6_sk(sk)->tclass |= INET_ECN_ECT_0; 54 } 55 56 static inline void INET_ECN_dontxmit(struct sock *sk) 57 { 58 inet_sk(sk)->tos &= ~INET_ECN_MASK; 59 if (inet6_sk(sk) != NULL) 60 inet6_sk(sk)->tclass &= ~INET_ECN_MASK; 61 } 62 63 #define IP6_ECN_flow_init(label) do { \ 64 (label) &= ~htonl(INET_ECN_MASK << 20); \ 65 } while (0) 66 67 #define IP6_ECN_flow_xmit(sk, label) do { \ 68 if (INET_ECN_is_capable(inet6_sk(sk)->tclass)) \ 69 (label) |= htonl(INET_ECN_ECT_0 << 20); \ 70 } while (0) 71 72 static inline int IP_ECN_set_ce(struct iphdr *iph) 73 { 74 u32 check = (__force u32)iph->check; 75 u32 ecn = (iph->tos + 1) & INET_ECN_MASK; 76 77 /* 78 * After the last operation we have (in binary): 79 * INET_ECN_NOT_ECT => 01 80 * INET_ECN_ECT_1 => 10 81 * INET_ECN_ECT_0 => 11 82 * INET_ECN_CE => 00 83 */ 84 if (!(ecn & 2)) 85 return !ecn; 86 87 /* 88 * The following gives us: 89 * INET_ECN_ECT_1 => check += htons(0xFFFD) 90 * INET_ECN_ECT_0 => check += htons(0xFFFE) 91 */ 92 check += (__force u16)htons(0xFFFB) + (__force u16)htons(ecn); 93 94 iph->check = (__force __sum16)(check + (check>=0xFFFF)); 95 iph->tos |= INET_ECN_CE; 96 return 1; 97 } 98 99 static inline void IP_ECN_clear(struct iphdr *iph) 100 { 101 iph->tos &= ~INET_ECN_MASK; 102 } 103 104 static inline void ipv4_copy_dscp(unsigned int dscp, struct iphdr *inner) 105 { 106 dscp &= ~INET_ECN_MASK; 107 ipv4_change_dsfield(inner, INET_ECN_MASK, dscp); 108 } 109 110 struct ipv6hdr; 111 112 static inline int IP6_ECN_set_ce(struct ipv6hdr *iph) 113 { 114 if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph))) 115 return 0; 116 *(__be32*)iph |= htonl(INET_ECN_CE << 20); 117 return 1; 118 } 119 120 static inline void IP6_ECN_clear(struct ipv6hdr *iph) 121 { 122 *(__be32*)iph &= ~htonl(INET_ECN_MASK << 20); 123 } 124 125 static inline void ipv6_copy_dscp(unsigned int dscp, struct ipv6hdr *inner) 126 { 127 dscp &= ~INET_ECN_MASK; 128 ipv6_change_dsfield(inner, INET_ECN_MASK, dscp); 129 } 130 131 static inline int INET_ECN_set_ce(struct sk_buff *skb) 132 { 133 switch (skb->protocol) { 134 case cpu_to_be16(ETH_P_IP): 135 if (skb->network_header + sizeof(struct iphdr) <= skb->tail) 136 return IP_ECN_set_ce(ip_hdr(skb)); 137 break; 138 139 case cpu_to_be16(ETH_P_IPV6): 140 if (skb->network_header + sizeof(struct ipv6hdr) <= skb->tail) 141 return IP6_ECN_set_ce(ipv6_hdr(skb)); 142 break; 143 } 144 145 return 0; 146 } 147 148 #endif 149