diff options
Diffstat (limited to 'include/net/inet_ecn.h')
| -rw-r--r-- | include/net/inet_ecn.h | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/include/net/inet_ecn.h b/include/net/inet_ecn.h new file mode 100644 index 000000000..84b20835b --- /dev/null +++ b/include/net/inet_ecn.h @@ -0,0 +1,226 @@ +#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(skb) + sizeof(struct iphdr) <= + skb_tail_pointer(skb)) + return IP_ECN_set_ce(ip_hdr(skb)); + break; + + case cpu_to_be16(ETH_P_IPV6): + if (skb_network_header(skb) + sizeof(struct ipv6hdr) <= + skb_tail_pointer(skb)) + return IP6_ECN_set_ce(ipv6_hdr(skb)); + break; + } + + return 0; +} + +/* + * RFC 6040 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 |