b5d9c9c281
INET_ECN_encapsulate() is better understood if we can read the official statement. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
148 lines
3.3 KiB
C
148 lines
3.3 KiB
C
#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 <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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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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static inline int IP6_ECN_set_ce(struct ipv6hdr *iph)
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{
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if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph)))
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return 0;
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*(__be32*)iph |= htonl(INET_ECN_CE << 20);
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return 1;
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}
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static inline void IP6_ECN_clear(struct ipv6hdr *iph)
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{
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*(__be32*)iph &= ~htonl(INET_ECN_MASK << 20);
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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) {
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case cpu_to_be16(ETH_P_IP):
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if (skb->network_header + sizeof(struct iphdr) <= skb->tail)
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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 + sizeof(struct ipv6hdr) <= skb->tail)
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return IP6_ECN_set_ce(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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#endif
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