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 static inline __u8 INET_ECN_encapsulate(__u8 outer, __u8 inner) 34 { 35 outer &= ~INET_ECN_MASK; 36 outer |= !INET_ECN_is_ce(inner) ? (inner & INET_ECN_MASK) : 37 INET_ECN_ECT_0; 38 return outer; 39 } 40 41 #define INET_ECN_xmit(sk) do { inet_sk(sk)->tos |= INET_ECN_ECT_0; } while (0) 42 #define INET_ECN_dontxmit(sk) \ 43 do { inet_sk(sk)->tos &= ~INET_ECN_MASK; } while (0) 44 45 #define IP6_ECN_flow_init(label) do { \ 46 (label) &= ~htonl(INET_ECN_MASK << 20); \ 47 } while (0) 48 49 #define IP6_ECN_flow_xmit(sk, label) do { \ 50 if (INET_ECN_is_capable(inet6_sk(sk)->tclass)) \ 51 (label) |= htonl(INET_ECN_ECT_0 << 20); \ 52 } while (0) 53 54 static inline int IP_ECN_set_ce(struct iphdr *iph) 55 { 56 u32 check = (__force u32)iph->check; 57 u32 ecn = (iph->tos + 1) & INET_ECN_MASK; 58 59 /* 60 * After the last operation we have (in binary): 61 * INET_ECN_NOT_ECT => 01 62 * INET_ECN_ECT_1 => 10 63 * INET_ECN_ECT_0 => 11 64 * INET_ECN_CE => 00 65 */ 66 if (!(ecn & 2)) 67 return !ecn; 68 69 /* 70 * The following gives us: 71 * INET_ECN_ECT_1 => check += htons(0xFFFD) 72 * INET_ECN_ECT_0 => check += htons(0xFFFE) 73 */ 74 check += (__force u16)htons(0xFFFB) + (__force u16)htons(ecn); 75 76 iph->check = (__force __sum16)(check + (check>=0xFFFF)); 77 iph->tos |= INET_ECN_CE; 78 return 1; 79 } 80 81 static inline void IP_ECN_clear(struct iphdr *iph) 82 { 83 iph->tos &= ~INET_ECN_MASK; 84 } 85 86 static inline void ipv4_copy_dscp(unsigned int dscp, struct iphdr *inner) 87 { 88 dscp &= ~INET_ECN_MASK; 89 ipv4_change_dsfield(inner, INET_ECN_MASK, dscp); 90 } 91 92 struct ipv6hdr; 93 94 static inline int IP6_ECN_set_ce(struct ipv6hdr *iph) 95 { 96 if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph))) 97 return 0; 98 *(__be32*)iph |= htonl(INET_ECN_CE << 20); 99 return 1; 100 } 101 102 static inline void IP6_ECN_clear(struct ipv6hdr *iph) 103 { 104 *(__be32*)iph &= ~htonl(INET_ECN_MASK << 20); 105 } 106 107 static inline void ipv6_copy_dscp(unsigned int dscp, struct ipv6hdr *inner) 108 { 109 dscp &= ~INET_ECN_MASK; 110 ipv6_change_dsfield(inner, INET_ECN_MASK, dscp); 111 } 112 113 static inline int INET_ECN_set_ce(struct sk_buff *skb) 114 { 115 switch (skb->protocol) { 116 case __constant_htons(ETH_P_IP): 117 if (skb->network_header + sizeof(struct iphdr) <= skb->tail) 118 return IP_ECN_set_ce(ip_hdr(skb)); 119 break; 120 121 case __constant_htons(ETH_P_IPV6): 122 if (skb->network_header + sizeof(struct ipv6hdr) <= skb->tail) 123 return IP6_ECN_set_ce(ipv6_hdr(skb)); 124 break; 125 } 126 127 return 0; 128 } 129 130 #endif 131