246 lines
6.1 KiB
C
246 lines
6.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _INET_ECN_H_
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#define _INET_ECN_H_
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#include <linux/ip.h>
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#include <linux/skbuff.h>
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#include <linux/if_vlan.h>
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#include <net/inet_sock.h>
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#include <net/dsfield.h>
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enum {
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INET_ECN_NOT_ECT = 0,
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INET_ECN_ECT_1 = 1,
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INET_ECN_ECT_0 = 2,
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INET_ECN_CE = 3,
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INET_ECN_MASK = 3,
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};
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extern int sysctl_tunnel_ecn_log;
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static inline int INET_ECN_is_ce(__u8 dsfield)
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{
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return (dsfield & INET_ECN_MASK) == INET_ECN_CE;
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}
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static inline int INET_ECN_is_not_ect(__u8 dsfield)
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{
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return (dsfield & INET_ECN_MASK) == INET_ECN_NOT_ECT;
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}
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static inline int INET_ECN_is_capable(__u8 dsfield)
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{
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return dsfield & INET_ECN_ECT_0;
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}
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/*
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* RFC 3168 9.1.1
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* The full-functionality option for ECN encapsulation is to copy the
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* ECN codepoint of the inside header to the outside header on
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* encapsulation if the inside header is not-ECT or ECT, and to set the
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* ECN codepoint of the outside header to ECT(0) if the ECN codepoint of
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* the inside header is CE.
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*/
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static inline __u8 INET_ECN_encapsulate(__u8 outer, __u8 inner)
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{
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outer &= ~INET_ECN_MASK;
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outer |= !INET_ECN_is_ce(inner) ? (inner & INET_ECN_MASK) :
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INET_ECN_ECT_0;
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return outer;
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}
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static inline void INET_ECN_xmit(struct sock *sk)
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{
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inet_sk(sk)->tos |= INET_ECN_ECT_0;
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if (inet6_sk(sk) != NULL)
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inet6_sk(sk)->tclass |= INET_ECN_ECT_0;
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}
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static inline void INET_ECN_dontxmit(struct sock *sk)
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{
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inet_sk(sk)->tos &= ~INET_ECN_MASK;
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if (inet6_sk(sk) != NULL)
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inet6_sk(sk)->tclass &= ~INET_ECN_MASK;
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}
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#define IP6_ECN_flow_init(label) do { \
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(label) &= ~htonl(INET_ECN_MASK << 20); \
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} while (0)
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#define IP6_ECN_flow_xmit(sk, label) do { \
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if (INET_ECN_is_capable(inet6_sk(sk)->tclass)) \
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(label) |= htonl(INET_ECN_ECT_0 << 20); \
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} while (0)
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static inline int IP_ECN_set_ce(struct iphdr *iph)
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{
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u32 check = (__force u32)iph->check;
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u32 ecn = (iph->tos + 1) & INET_ECN_MASK;
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/*
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* After the last operation we have (in binary):
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* INET_ECN_NOT_ECT => 01
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* INET_ECN_ECT_1 => 10
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* INET_ECN_ECT_0 => 11
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* INET_ECN_CE => 00
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*/
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if (!(ecn & 2))
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return !ecn;
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/*
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* The following gives us:
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* INET_ECN_ECT_1 => check += htons(0xFFFD)
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* INET_ECN_ECT_0 => check += htons(0xFFFE)
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*/
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check += (__force u16)htons(0xFFFB) + (__force u16)htons(ecn);
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iph->check = (__force __sum16)(check + (check>=0xFFFF));
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iph->tos |= INET_ECN_CE;
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return 1;
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}
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static inline void IP_ECN_clear(struct iphdr *iph)
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{
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iph->tos &= ~INET_ECN_MASK;
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}
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static inline void ipv4_copy_dscp(unsigned int dscp, struct iphdr *inner)
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{
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dscp &= ~INET_ECN_MASK;
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ipv4_change_dsfield(inner, INET_ECN_MASK, dscp);
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}
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struct ipv6hdr;
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/* Note:
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* IP_ECN_set_ce() has to tweak IPV4 checksum when setting CE,
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* meaning both changes have no effect on skb->csum if/when CHECKSUM_COMPLETE
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* In IPv6 case, no checksum compensates the change in IPv6 header,
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* so we have to update skb->csum.
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*/
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static inline int IP6_ECN_set_ce(struct sk_buff *skb, struct ipv6hdr *iph)
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{
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__be32 from, to;
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if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph)))
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return 0;
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from = *(__be32 *)iph;
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to = from | htonl(INET_ECN_CE << 20);
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*(__be32 *)iph = to;
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if (skb->ip_summed == CHECKSUM_COMPLETE)
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skb->csum = csum_add(csum_sub(skb->csum, (__force __wsum)from),
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(__force __wsum)to);
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return 1;
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}
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static inline void ipv6_copy_dscp(unsigned int dscp, struct ipv6hdr *inner)
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{
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dscp &= ~INET_ECN_MASK;
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ipv6_change_dsfield(inner, INET_ECN_MASK, dscp);
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}
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static inline int INET_ECN_set_ce(struct sk_buff *skb)
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{
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switch (skb_protocol(skb, true)) {
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case cpu_to_be16(ETH_P_IP):
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if (skb_network_header(skb) + sizeof(struct iphdr) <=
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skb_tail_pointer(skb))
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return IP_ECN_set_ce(ip_hdr(skb));
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break;
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case cpu_to_be16(ETH_P_IPV6):
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if (skb_network_header(skb) + sizeof(struct ipv6hdr) <=
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skb_tail_pointer(skb))
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return IP6_ECN_set_ce(skb, ipv6_hdr(skb));
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break;
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}
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return 0;
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}
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/*
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* RFC 6040 4.2
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* To decapsulate the inner header at the tunnel egress, a compliant
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* tunnel egress MUST set the outgoing ECN field to the codepoint at the
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* intersection of the appropriate arriving inner header (row) and outer
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* header (column) in Figure 4
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*
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* +---------+------------------------------------------------+
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* |Arriving | Arriving Outer Header |
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* | Inner +---------+------------+------------+------------+
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* | Header | Not-ECT | ECT(0) | ECT(1) | CE |
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* +---------+---------+------------+------------+------------+
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* | Not-ECT | Not-ECT |Not-ECT(!!!)|Not-ECT(!!!)| <drop>(!!!)|
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* | ECT(0) | ECT(0) | ECT(0) | ECT(1) | CE |
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* | ECT(1) | ECT(1) | ECT(1) (!) | ECT(1) | CE |
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* | CE | CE | CE | CE(!!!)| CE |
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* +---------+---------+------------+------------+------------+
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*
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* Figure 4: New IP in IP Decapsulation Behaviour
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*
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* returns 0 on success
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* 1 if something is broken and should be logged (!!! above)
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* 2 if packet should be dropped
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*/
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static inline int INET_ECN_decapsulate(struct sk_buff *skb,
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__u8 outer, __u8 inner)
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{
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if (INET_ECN_is_not_ect(inner)) {
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switch (outer & INET_ECN_MASK) {
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case INET_ECN_NOT_ECT:
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return 0;
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case INET_ECN_ECT_0:
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case INET_ECN_ECT_1:
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return 1;
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case INET_ECN_CE:
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return 2;
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}
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}
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if (INET_ECN_is_ce(outer))
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INET_ECN_set_ce(skb);
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return 0;
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}
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static inline int IP_ECN_decapsulate(const struct iphdr *oiph,
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struct sk_buff *skb)
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{
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__u8 inner;
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switch (skb_protocol(skb, true)) {
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case htons(ETH_P_IP):
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inner = ip_hdr(skb)->tos;
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break;
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case htons(ETH_P_IPV6):
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inner = ipv6_get_dsfield(ipv6_hdr(skb));
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break;
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default:
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return 0;
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}
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return INET_ECN_decapsulate(skb, oiph->tos, inner);
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}
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static inline int IP6_ECN_decapsulate(const struct ipv6hdr *oipv6h,
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struct sk_buff *skb)
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{
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__u8 inner;
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switch (skb_protocol(skb, true)) {
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case htons(ETH_P_IP):
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inner = ip_hdr(skb)->tos;
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break;
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case htons(ETH_P_IPV6):
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inner = ipv6_get_dsfield(ipv6_hdr(skb));
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break;
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default:
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return 0;
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}
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return INET_ECN_decapsulate(skb, ipv6_get_dsfield(oipv6h), inner);
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}
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#endif
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