[thirdparty/linux.git] / include / net / inet_ecn.h

/* SPDX-License-Identifier: GPL-2.0 */
#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 int IP_ECN_set_ect1(struct iphdr *iph)
{
	u32 check = (__force u32)iph->check;

	if ((iph->tos & INET_ECN_MASK) != INET_ECN_ECT_0)
		return 0;

	check += (__force u16)htons(0x100);

	iph->check = (__force __sum16)(check + (check>=0xFFFF));
	iph->tos ^= INET_ECN_MASK;
	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;

/* Note:
 * IP_ECN_set_ce() has to tweak IPV4 checksum when setting CE,
 * meaning both changes have no effect on skb->csum if/when CHECKSUM_COMPLETE
 * In IPv6 case, no checksum compensates the change in IPv6 header,
 * so we have to update skb->csum.
 */
static inline int IP6_ECN_set_ce(struct sk_buff *skb, struct ipv6hdr *iph)
{
	__be32 from, to;

	if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph)))
		return 0;

	from = *(__be32 *)iph;
	to = from | htonl(INET_ECN_CE << 20);
	*(__be32 *)iph = to;
	if (skb->ip_summed == CHECKSUM_COMPLETE)
		skb->csum = csum_add(csum_sub(skb->csum, (__force __wsum)from),
				     (__force __wsum)to);
	return 1;
}

static inline int IP6_ECN_set_ect1(struct sk_buff *skb, struct ipv6hdr *iph)
{
	__be32 from, to;

	if ((ipv6_get_dsfield(iph) & INET_ECN_MASK) != INET_ECN_ECT_0)
		return 0;

	from = *(__be32 *)iph;
	to = from ^ htonl(INET_ECN_MASK << 20);
	*(__be32 *)iph = to;
	if (skb->ip_summed == CHECKSUM_COMPLETE)
		skb->csum = csum_add(csum_sub(skb->csum, (__force __wsum)from),
				     (__force __wsum)to);
	return 1;
}

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(skb, ipv6_hdr(skb));
		break;
	}

	return 0;
}

static inline int INET_ECN_set_ect1(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_ect1(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_ect1(skb, 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(__u8 outer, __u8 inner, bool *set_ce)
{
	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;
		}
	}

	*set_ce = INET_ECN_is_ce(outer);
	return 0;
}

static inline int INET_ECN_decapsulate(struct sk_buff *skb,
				       __u8 outer, __u8 inner)
{
	bool set_ce = false;
	int rc;

	rc = __INET_ECN_decapsulate(outer, inner, &set_ce);
	if (!rc) {
		if (set_ce)
			INET_ECN_set_ce(skb);
		else if ((outer & INET_ECN_MASK) == INET_ECN_ECT_1)
			INET_ECN_set_ect1(skb);
	}

	return rc;
}

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
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
1da177e4 LT	2	#ifndef _INET_ECN_H_
	3	#define _INET_ECN_H_
	4
	5	#include <linux/ip.h>
2566a509	6	#include <linux/skbuff.h>
14c85021 ACM	7
14c85021 ACM	8	#include <net/inet_sock.h>
1da177e4 LT	9	#include <net/dsfield.h>
	10
	11	enum {
	12	INET_ECN_NOT_ECT = 0,
	13	INET_ECN_ECT_1 = 1,
	14	INET_ECN_ECT_0 = 2,
	15	INET_ECN_CE = 3,
	16	INET_ECN_MASK = 3,
	17	};
	18
eccc1bb8	19	extern int sysctl_tunnel_ecn_log;
eccc1bb8	20
1da177e4 LT	21	static inline int INET_ECN_is_ce(__u8 dsfield)
	22	{
	23	return (dsfield & INET_ECN_MASK) == INET_ECN_CE;
	24	}
	25
	26	static inline int INET_ECN_is_not_ect(__u8 dsfield)
	27	{
	28	return (dsfield & INET_ECN_MASK) == INET_ECN_NOT_ECT;
	29	}
	30
	31	static inline int INET_ECN_is_capable(__u8 dsfield)
	32	{
a02cec21	33	return dsfield & INET_ECN_ECT_0;
1da177e4 LT	34	}
1da177e4 LT	35
b5d9c9c2 ED	36	/*
	37	* RFC 3168 9.1.1
	38	* The full-functionality option for ECN encapsulation is to copy the
	39	* ECN codepoint of the inside header to the outside header on
	40	* encapsulation if the inside header is not-ECT or ECT, and to set the
	41	* ECN codepoint of the outside header to ECT(0) if the ECN codepoint of
	42	* the inside header is CE.
	43	*/
1da177e4 LT	44	static inline __u8 INET_ECN_encapsulate(__u8 outer, __u8 inner)
	45	{
	46	outer &= ~INET_ECN_MASK;
	47	outer \|= !INET_ECN_is_ce(inner) ? (inner & INET_ECN_MASK) :
	48	INET_ECN_ECT_0;
	49	return outer;
	50	}
	51
ca067070 SG	52	static inline void INET_ECN_xmit(struct sock *sk)
	53	{
	54	inet_sk(sk)->tos \|= INET_ECN_ECT_0;
	55	if (inet6_sk(sk) != NULL)
	56	inet6_sk(sk)->tclass \|= INET_ECN_ECT_0;
	57	}
	58
	59	static inline void INET_ECN_dontxmit(struct sock *sk)
	60	{
	61	inet_sk(sk)->tos &= ~INET_ECN_MASK;
	62	if (inet6_sk(sk) != NULL)
	63	inet6_sk(sk)->tclass &= ~INET_ECN_MASK;
	64	}
1da177e4 LT	65
	66	#define IP6_ECN_flow_init(label) do { \
	67	(label) &= ~htonl(INET_ECN_MASK << 20); \
	68	} while (0)
	69
	70	#define IP6_ECN_flow_xmit(sk, label) do { \
e9df2e8f	71	if (INET_ECN_is_capable(inet6_sk(sk)->tclass)) \
95026cd2	72	(label) \|= htonl(INET_ECN_ECT_0 << 20); \
1da177e4 LT	73	} while (0)
1da177e4 LT	74
2566a509	75	static inline int IP_ECN_set_ce(struct iphdr *iph)
1da177e4	76	{
5c78f275	77	u32 check = (__force u32)iph->check;
1da177e4 LT	78	u32 ecn = (iph->tos + 1) & INET_ECN_MASK;
	79
	80	/*
	81	* After the last operation we have (in binary):
	82	* INET_ECN_NOT_ECT => 01
	83	* INET_ECN_ECT_1 => 10
	84	* INET_ECN_ECT_0 => 11
	85	* INET_ECN_CE => 00
	86	*/
	87	if (!(ecn & 2))
2566a509	88	return !ecn;
1da177e4 LT	89
	90	/*
	91	* The following gives us:
	92	* INET_ECN_ECT_1 => check += htons(0xFFFD)
	93	* INET_ECN_ECT_0 => check += htons(0xFFFE)
	94	*/
5c78f275	95	check += (__force u16)htons(0xFFFB) + (__force u16)htons(ecn);
1da177e4	96
5c78f275	97	iph->check = (__force __sum16)(check + (check>=0xFFFF));
1da177e4	98	iph->tos \|= INET_ECN_CE;
2566a509	99	return 1;
1da177e4 LT	100	}
1da177e4 LT	101
b7237487 THJ	102	static inline int IP_ECN_set_ect1(struct iphdr *iph)
	103	{
	104	u32 check = (__force u32)iph->check;
	105
	106	if ((iph->tos & INET_ECN_MASK) != INET_ECN_ECT_0)
	107	return 0;
	108
	109	check += (__force u16)htons(0x100);
	110
	111	iph->check = (__force __sum16)(check + (check>=0xFFFF));
	112	iph->tos ^= INET_ECN_MASK;
	113	return 1;
	114	}
	115
1da177e4 LT	116	static inline void IP_ECN_clear(struct iphdr *iph)
	117	{
	118	iph->tos &= ~INET_ECN_MASK;
	119	}
	120
29bb43b4	121	static inline void ipv4_copy_dscp(unsigned int dscp, struct iphdr *inner)
1da177e4	122	{
29bb43b4	123	dscp &= ~INET_ECN_MASK;
1da177e4 LT	124	ipv4_change_dsfield(inner, INET_ECN_MASK, dscp);
	125	}
	126
	127	struct ipv6hdr;
	128
34ae6a1a ED	129	/* Note:
	130	* IP_ECN_set_ce() has to tweak IPV4 checksum when setting CE,
	131	* meaning both changes have no effect on skb->csum if/when CHECKSUM_COMPLETE
	132	* In IPv6 case, no checksum compensates the change in IPv6 header,
	133	* so we have to update skb->csum.
	134	*/
	135	static inline int IP6_ECN_set_ce(struct sk_buff skb, struct ipv6hdr iph)
1da177e4	136	{
34ae6a1a ED	137	__be32 from, to;
34ae6a1a ED	138
1da177e4	139	if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph)))
2566a509	140	return 0;
34ae6a1a ED	141
	142	from = (__be32 )iph;
	143	to = from \| htonl(INET_ECN_CE << 20);
	144	(__be32 )iph = to;
	145	if (skb->ip_summed == CHECKSUM_COMPLETE)
c15c0ab1 JB	146	skb->csum = csum_add(csum_sub(skb->csum, (__force __wsum)from),
c15c0ab1 JB	147	(__force __wsum)to);
2566a509	148	return 1;
1da177e4 LT	149	}
1da177e4 LT	150
b7237487 THJ	151	static inline int IP6_ECN_set_ect1(struct sk_buff skb, struct ipv6hdr iph)
	152	{
	153	__be32 from, to;
	154
	155	if ((ipv6_get_dsfield(iph) & INET_ECN_MASK) != INET_ECN_ECT_0)
	156	return 0;
	157
	158	from = (__be32 )iph;
	159	to = from ^ htonl(INET_ECN_MASK << 20);
	160	(__be32 )iph = to;
	161	if (skb->ip_summed == CHECKSUM_COMPLETE)
	162	skb->csum = csum_add(csum_sub(skb->csum, (__force __wsum)from),
	163	(__force __wsum)to);
	164	return 1;
	165	}
	166
29bb43b4	167	static inline void ipv6_copy_dscp(unsigned int dscp, struct ipv6hdr *inner)
1da177e4	168	{
29bb43b4	169	dscp &= ~INET_ECN_MASK;
1da177e4 LT	170	ipv6_change_dsfield(inner, INET_ECN_MASK, dscp);
	171	}
	172
2566a509 TG	173	static inline int INET_ECN_set_ce(struct sk_buff *skb)
	174	{
	175	switch (skb->protocol) {
f3a7c66b	176	case cpu_to_be16(ETH_P_IP):
ced14f68 SH	177	if (skb_network_header(skb) + sizeof(struct iphdr) <=
ced14f68 SH	178	skb_tail_pointer(skb))
eddc9ec5	179	return IP_ECN_set_ce(ip_hdr(skb));
2566a509 TG	180	break;
2566a509 TG	181
f3a7c66b	182	case cpu_to_be16(ETH_P_IPV6):
ced14f68 SH	183	if (skb_network_header(skb) + sizeof(struct ipv6hdr) <=
ced14f68 SH	184	skb_tail_pointer(skb))
34ae6a1a	185	return IP6_ECN_set_ce(skb, ipv6_hdr(skb));
2566a509 TG	186	break;
	187	}
	188
	189	return 0;
	190	}
	191
b7237487 THJ	192	static inline int INET_ECN_set_ect1(struct sk_buff *skb)
	193	{
	194	switch (skb->protocol) {
	195	case cpu_to_be16(ETH_P_IP):
	196	if (skb_network_header(skb) + sizeof(struct iphdr) <=
	197	skb_tail_pointer(skb))
	198	return IP_ECN_set_ect1(ip_hdr(skb));
	199	break;
	200
	201	case cpu_to_be16(ETH_P_IPV6):
	202	if (skb_network_header(skb) + sizeof(struct ipv6hdr) <=
	203	skb_tail_pointer(skb))
	204	return IP6_ECN_set_ect1(skb, ipv6_hdr(skb));
	205	break;
	206	}
	207
	208	return 0;
	209	}
	210
eccc1bb8	211	/*
d28071d1	212	* RFC 6040 4.2
eccc1bb8	213	* To decapsulate the inner header at the tunnel egress, a compliant
	214	* tunnel egress MUST set the outgoing ECN field to the codepoint at the
	215	* intersection of the appropriate arriving inner header (row) and outer
	216	* header (column) in Figure 4
	217	*
	218	* +---------+------------------------------------------------+
	219	* \|Arriving \| Arriving Outer Header \|
	220	* \| Inner +---------+------------+------------+------------+
	221	* \| Header \| Not-ECT \| ECT(0) \| ECT(1) \| CE \|
	222	* +---------+---------+------------+------------+------------+
	223	* \| Not-ECT \| Not-ECT \|Not-ECT(!!!)\|Not-ECT(!!!)\| <drop>(!!!)\|
	224	* \| ECT(0) \| ECT(0) \| ECT(0) \| ECT(1) \| CE \|
	225	* \| ECT(1) \| ECT(1) \| ECT(1) (!) \| ECT(1) \| CE \|
	226	* \| CE \| CE \| CE \| CE(!!!)\| CE \|
	227	* +---------+---------+------------+------------+------------+
	228	*
	229	* Figure 4: New IP in IP Decapsulation Behaviour
	230	*
	231	* returns 0 on success
	232	* 1 if something is broken and should be logged (!!! above)
	233	* 2 if packet should be dropped
	234	*/
28e45033	235	static inline int __INET_ECN_decapsulate(__u8 outer, __u8 inner, bool *set_ce)
eccc1bb8	236	{
	237	if (INET_ECN_is_not_ect(inner)) {
	238	switch (outer & INET_ECN_MASK) {
	239	case INET_ECN_NOT_ECT:
	240	return 0;
	241	case INET_ECN_ECT_0:
	242	case INET_ECN_ECT_1:
	243	return 1;
	244	case INET_ECN_CE:
	245	return 2;
	246	}
	247	}
	248
28e45033 IS	249	*set_ce = INET_ECN_is_ce(outer);
	250	return 0;
	251	}
	252
	253	static inline int INET_ECN_decapsulate(struct sk_buff *skb,
	254	__u8 outer, __u8 inner)
	255	{
	256	bool set_ce = false;
	257	int rc;
	258
	259	rc = __INET_ECN_decapsulate(outer, inner, &set_ce);
b7237487 THJ	260	if (!rc) {
	261	if (set_ce)
	262	INET_ECN_set_ce(skb);
	263	else if ((outer & INET_ECN_MASK) == INET_ECN_ECT_1)
	264	INET_ECN_set_ect1(skb);
	265	}
eccc1bb8	266
28e45033	267	return rc;
eccc1bb8	268	}
	269
	270	static inline int IP_ECN_decapsulate(const struct iphdr *oiph,
	271	struct sk_buff *skb)
	272	{
	273	__u8 inner;
	274
	275	if (skb->protocol == htons(ETH_P_IP))
	276	inner = ip_hdr(skb)->tos;
	277	else if (skb->protocol == htons(ETH_P_IPV6))
	278	inner = ipv6_get_dsfield(ipv6_hdr(skb));
	279	else
	280	return 0;
	281
	282	return INET_ECN_decapsulate(skb, oiph->tos, inner);
	283	}
	284
	285	static inline int IP6_ECN_decapsulate(const struct ipv6hdr *oipv6h,
	286	struct sk_buff *skb)
	287	{
	288	__u8 inner;
	289
	290	if (skb->protocol == htons(ETH_P_IP))
	291	inner = ip_hdr(skb)->tos;
	292	else if (skb->protocol == htons(ETH_P_IPV6))
	293	inner = ipv6_get_dsfield(ipv6_hdr(skb));
	294	else
	295	return 0;
	296
	297	return INET_ECN_decapsulate(skb, ipv6_get_dsfield(oipv6h), inner);
	298	}
1da177e4	299	#endif