| 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 |