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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 | #ifndef _INET_ECN_H_ #define _INET_ECN_H_ #include <linux/ip.h> #include <linux/skbuff.h> #include <net/inet_sock.h> #include <net/dsfield.h> enum { INET_ECN_NOT_ECT = 0, INET_ECN_ECT_1 = 1, INET_ECN_ECT_0 = 2, INET_ECN_CE = 3, INET_ECN_MASK = 3, }; extern int sysctl_tunnel_ecn_log; static inline int INET_ECN_is_ce(__u8 dsfield) { return (dsfield & INET_ECN_MASK) == INET_ECN_CE; } static inline int INET_ECN_is_not_ect(__u8 dsfield) { return (dsfield & INET_ECN_MASK) == INET_ECN_NOT_ECT; } static inline int INET_ECN_is_capable(__u8 dsfield) { return dsfield & INET_ECN_ECT_0; } /* * RFC 3168 9.1.1 * The full-functionality option for ECN encapsulation is to copy the * ECN codepoint of the inside header to the outside header on * encapsulation if the inside header is not-ECT or ECT, and to set the * ECN codepoint of the outside header to ECT(0) if the ECN codepoint of * the inside header is CE. */ static inline __u8 INET_ECN_encapsulate(__u8 outer, __u8 inner) { outer &= ~INET_ECN_MASK; outer |= !INET_ECN_is_ce(inner) ? (inner & INET_ECN_MASK) : INET_ECN_ECT_0; return outer; } static inline void INET_ECN_xmit(struct sock *sk) { inet_sk(sk)->tos |= INET_ECN_ECT_0; if (inet6_sk(sk) != NULL) inet6_sk(sk)->tclass |= INET_ECN_ECT_0; } static inline void INET_ECN_dontxmit(struct sock *sk) { inet_sk(sk)->tos &= ~INET_ECN_MASK; if (inet6_sk(sk) != NULL) inet6_sk(sk)->tclass &= ~INET_ECN_MASK; } #define IP6_ECN_flow_init(label) do { \ (label) &= ~htonl(INET_ECN_MASK << 20); \ } while (0) #define IP6_ECN_flow_xmit(sk, label) do { \ if (INET_ECN_is_capable(inet6_sk(sk)->tclass)) \ (label) |= htonl(INET_ECN_ECT_0 << 20); \ } while (0) static inline int IP_ECN_set_ce(struct iphdr *iph) { u32 check = (__force u32)iph->check; u32 ecn = (iph->tos + 1) & INET_ECN_MASK; /* * After the last operation we have (in binary): * INET_ECN_NOT_ECT => 01 * INET_ECN_ECT_1 => 10 * INET_ECN_ECT_0 => 11 * INET_ECN_CE => 00 */ if (!(ecn & 2)) return !ecn; /* * The following gives us: * INET_ECN_ECT_1 => check += htons(0xFFFD) * INET_ECN_ECT_0 => check += htons(0xFFFE) */ check += (__force u16)htons(0xFFFB) + (__force u16)htons(ecn); iph->check = (__force __sum16)(check + (check>=0xFFFF)); iph->tos |= INET_ECN_CE; return 1; } static inline void IP_ECN_clear(struct iphdr *iph) { iph->tos &= ~INET_ECN_MASK; } static inline void ipv4_copy_dscp(unsigned int dscp, struct iphdr *inner) { dscp &= ~INET_ECN_MASK; ipv4_change_dsfield(inner, INET_ECN_MASK, dscp); } struct ipv6hdr; static inline int IP6_ECN_set_ce(struct ipv6hdr *iph) { if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph))) return 0; *(__be32*)iph |= htonl(INET_ECN_CE << 20); return 1; } static inline void IP6_ECN_clear(struct ipv6hdr *iph) { *(__be32*)iph &= ~htonl(INET_ECN_MASK << 20); } static inline void ipv6_copy_dscp(unsigned int dscp, struct ipv6hdr *inner) { dscp &= ~INET_ECN_MASK; ipv6_change_dsfield(inner, INET_ECN_MASK, dscp); } static inline int INET_ECN_set_ce(struct sk_buff *skb) { switch (skb->protocol) { case cpu_to_be16(ETH_P_IP): if (skb->network_header + sizeof(struct iphdr) <= skb->tail) return IP_ECN_set_ce(ip_hdr(skb)); break; case cpu_to_be16(ETH_P_IPV6): if (skb->network_header + sizeof(struct ipv6hdr) <= skb->tail) return IP6_ECN_set_ce(ipv6_hdr(skb)); break; } return 0; } /* * RFC 6080 4.2 * To decapsulate the inner header at the tunnel egress, a compliant * tunnel egress MUST set the outgoing ECN field to the codepoint at the * intersection of the appropriate arriving inner header (row) and outer * header (column) in Figure 4 * * +---------+------------------------------------------------+ * |Arriving | Arriving Outer Header | * | Inner +---------+------------+------------+------------+ * | Header | Not-ECT | ECT(0) | ECT(1) | CE | * +---------+---------+------------+------------+------------+ * | Not-ECT | Not-ECT |Not-ECT(!!!)|Not-ECT(!!!)| <drop>(!!!)| * | ECT(0) | ECT(0) | ECT(0) | ECT(1) | CE | * | ECT(1) | ECT(1) | ECT(1) (!) | ECT(1) | CE | * | CE | CE | CE | CE(!!!)| CE | * +---------+---------+------------+------------+------------+ * * Figure 4: New IP in IP Decapsulation Behaviour * * returns 0 on success * 1 if something is broken and should be logged (!!! above) * 2 if packet should be dropped */ static inline int INET_ECN_decapsulate(struct sk_buff *skb, __u8 outer, __u8 inner) { if (INET_ECN_is_not_ect(inner)) { switch (outer & INET_ECN_MASK) { case INET_ECN_NOT_ECT: return 0; case INET_ECN_ECT_0: case INET_ECN_ECT_1: return 1; case INET_ECN_CE: return 2; } } if (INET_ECN_is_ce(outer)) INET_ECN_set_ce(skb); return 0; } static inline int IP_ECN_decapsulate(const struct iphdr *oiph, struct sk_buff *skb) { __u8 inner; if (skb->protocol == htons(ETH_P_IP)) inner = ip_hdr(skb)->tos; else if (skb->protocol == htons(ETH_P_IPV6)) inner = ipv6_get_dsfield(ipv6_hdr(skb)); else return 0; return INET_ECN_decapsulate(skb, oiph->tos, inner); } static inline int IP6_ECN_decapsulate(const struct ipv6hdr *oipv6h, struct sk_buff *skb) { __u8 inner; if (skb->protocol == htons(ETH_P_IP)) inner = ip_hdr(skb)->tos; else if (skb->protocol == htons(ETH_P_IPV6)) inner = ipv6_get_dsfield(ipv6_hdr(skb)); else return 0; return INET_ECN_decapsulate(skb, ipv6_get_dsfield(oipv6h), inner); } #endif |