[PATCH net-next 0/4] ila: make identifier format optional and other fixes

[PATCH net-next 0/4] ila: make identifier format optional and other fixes

[Tom Herbert]

The identifier type and checksum neutral mapping bits are optional
in identifier formats. This patch set fixes the implementation to
make them optional and configurable.

Specific items:

  - Clean up checksum diff code in ILA
  - Add checksum neutral mapping auto so that checksum neutral
    mapping can be configured without requiring use of the C-bit
  - Add identifier type configuration and allow identifier
    type to be configured so that the identifier type field does
    not need to be present
  - Added ILA documention: ila.txt

I have patches for ILA in iproute2 that will be poseted separately.

Tested: Ran netperf TCP_RR on various combinations of checksum
mode and the two supported identifier types.

Tom Herbert (4):
  ila: cleanup checksum diff
  ila: add checksum neutral map auto
  ila: allow configuraiton of identifier type
  ila: Add ila.txt

 Documentation/networking/ila.txt | 286 +++++++++++++++++++++++++++++++++++++++
 include/uapi/linux/ila.h         |  14 ++
 net/ipv6/ila/ila.h               |  12 +-
 net/ipv6/ila/ila_common.c        | 104 +++++++-------
 net/ipv6/ila/ila_lwt.c           |  62 +++++++--
 net/ipv6/ila/ila_xlat.c          |  26 ++--
 6 files changed, 426 insertions(+), 78 deletions(-)
 create mode 100644 Documentation/networking/ila.txt

-- 
2.11.0

[PATCH net-next 1/4] ila: cleanup checksum diff

[Tom Herbert]

Consolidate computing checksum diff into one function.

Add get_csum_diff_iaddr that computes the checksum diff between
an address argument and locator being written. get_csum_diff
calls this using the destination address in the IP header as
the argument.

Also moved ila_init_saved_csum to be close to the checksum
diff functions.

Signed-off-by: Tom Herbert <tom@quantonium.net>
---
 net/ipv6/ila/ila_common.c | 39 ++++++++++++++++++---------------------
 1 file changed, 18 insertions(+), 21 deletions(-)

diff --git a/net/ipv6/ila/ila_common.c b/net/ipv6/ila/ila_common.c
index aba0998ddbfb..f1d9248d8b86 100644
--- a/net/ipv6/ila/ila_common.c
+++ b/net/ipv6/ila/ila_common.c
@@ -13,15 +13,28 @@
 #include <uapi/linux/ila.h>
 #include "ila.h"
 
-static __wsum get_csum_diff(struct ipv6hdr *ip6h, struct ila_params *p)
+void ila_init_saved_csum(struct ila_params *p)
 {
-	struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
+	if (!p->locator_match.v64)
+		return;
+
+	p->csum_diff = compute_csum_diff8(
+				(__be32 *)&p->locator,
+				(__be32 *)&p->locator_match);
+}
 
+static __wsum get_csum_diff_iaddr(struct ila_addr *iaddr, struct ila_params *p)
+{
 	if (p->locator_match.v64)
 		return p->csum_diff;
 	else
-		return compute_csum_diff8((__be32 *)&iaddr->loc,
-					  (__be32 *)&p->locator);
+		return compute_csum_diff8((__be32 *)&p->locator,
+					  (__be32 *)&iaddr->loc);
+}
+
+static __wsum get_csum_diff(struct ipv6hdr *ip6h, struct ila_params *p)
+{
+	return get_csum_diff_iaddr(ila_a2i(&ip6h->daddr), p);
 }
 
 static void ila_csum_do_neutral(struct ila_addr *iaddr,
@@ -30,13 +43,7 @@ static void ila_csum_do_neutral(struct ila_addr *iaddr,
 	__sum16 *adjust = (__force __sum16 *)&iaddr->ident.v16[3];
 	__wsum diff, fval;
 
-	/* Check if checksum adjust value has been cached */
-	if (p->locator_match.v64) {
-		diff = p->csum_diff;
-	} else {
-		diff = compute_csum_diff8((__be32 *)&p->locator,
-					  (__be32 *)iaddr);
-	}
+	diff = get_csum_diff_iaddr(iaddr, p);
 
 	fval = (__force __wsum)(ila_csum_neutral_set(iaddr->ident) ?
 			CSUM_NEUTRAL_FLAG : ~CSUM_NEUTRAL_FLAG);
@@ -134,16 +141,6 @@ void ila_update_ipv6_locator(struct sk_buff *skb, struct ila_params *p,
 	iaddr->loc = p->locator;
 }
 
-void ila_init_saved_csum(struct ila_params *p)
-{
-	if (!p->locator_match.v64)
-		return;
-
-	p->csum_diff = compute_csum_diff8(
-				(__be32 *)&p->locator,
-				(__be32 *)&p->locator_match);
-}
-
 static int __init ila_init(void)
 {
 	int ret;
-- 
2.11.0

[PATCH net-next 2/4] ila: add checksum neutral map auto

[Tom Herbert]

Add checksum neutral auto that performs checksum neutral mapping
without using the C-bit. This is enabled by configuration of
a mapping.

The checksum neutral function has been split into
ila_csum_do_neutral_fmt and ila_csum_do_neutral_nofmt. The former
handles the C-bit and includes it in the adjustment value. The latter
just sets the adjustment value on the locator diff only.

Added configuration for checksum neutral map aut in ila_lwt
and ila_xlat.

Signed-off-by: Tom Herbert <tom@quantonium.net>
---
 include/uapi/linux/ila.h  |  1 +
 net/ipv6/ila/ila_common.c | 65 ++++++++++++++++++++++++++++-------------------
 net/ipv6/ila/ila_lwt.c    | 29 +++++++++++----------
 net/ipv6/ila/ila_xlat.c   | 10 +++++---
 4 files changed, 61 insertions(+), 44 deletions(-)

diff --git a/include/uapi/linux/ila.h b/include/uapi/linux/ila.h
index 948c0a91e11b..0132b14a556f 100644
--- a/include/uapi/linux/ila.h
+++ b/include/uapi/linux/ila.h
@@ -40,6 +40,7 @@ enum {
 	ILA_CSUM_ADJUST_TRANSPORT,
 	ILA_CSUM_NEUTRAL_MAP,
 	ILA_CSUM_NO_ACTION,
+	ILA_CSUM_NEUTRAL_MAP_AUTO,
 };
 
 #endif /* _UAPI_LINUX_ILA_H */
diff --git a/net/ipv6/ila/ila_common.c b/net/ipv6/ila/ila_common.c
index f1d9248d8b86..8c88ecf29b93 100644
--- a/net/ipv6/ila/ila_common.c
+++ b/net/ipv6/ila/ila_common.c
@@ -37,8 +37,8 @@ static __wsum get_csum_diff(struct ipv6hdr *ip6h, struct ila_params *p)
 	return get_csum_diff_iaddr(ila_a2i(&ip6h->daddr), p);
 }
 
-static void ila_csum_do_neutral(struct ila_addr *iaddr,
-				struct ila_params *p)
+static void ila_csum_do_neutral_fmt(struct ila_addr *iaddr,
+				    struct ila_params *p)
 {
 	__sum16 *adjust = (__force __sum16 *)&iaddr->ident.v16[3];
 	__wsum diff, fval;
@@ -60,13 +60,23 @@ static void ila_csum_do_neutral(struct ila_addr *iaddr,
 	iaddr->ident.csum_neutral ^= 1;
 }
 
-static void ila_csum_adjust_transport(struct sk_buff *skb,
+static void ila_csum_do_neutral_nofmt(struct ila_addr *iaddr,
 				      struct ila_params *p)
 {
+	__sum16 *adjust = (__force __sum16 *)&iaddr->ident.v16[3];
 	__wsum diff;
-	struct ipv6hdr *ip6h = ipv6_hdr(skb);
-	struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
+
+	diff = get_csum_diff_iaddr(iaddr, p);
+
+	*adjust = ~csum_fold(csum_add(diff, csum_unfold(*adjust)));
+}
+
+static void ila_csum_adjust_transport(struct sk_buff *skb,
+				      struct ila_params *p)
+{
 	size_t nhoff = sizeof(struct ipv6hdr);
+	struct ipv6hdr *ip6h = ipv6_hdr(skb);
+	__wsum diff;
 
 	switch (ip6h->nexthdr) {
 	case NEXTHDR_TCP:
@@ -105,36 +115,39 @@ static void ila_csum_adjust_transport(struct sk_buff *skb,
 		}
 		break;
 	}
-
-	/* Now change destination address */
-	iaddr->loc = p->locator;
 }
 
 void ila_update_ipv6_locator(struct sk_buff *skb, struct ila_params *p,
-			     bool set_csum_neutral)
+			     bool sir2ila)
 {
 	struct ipv6hdr *ip6h = ipv6_hdr(skb);
 	struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
 
-	/* First deal with the transport checksum */
-	if (ila_csum_neutral_set(iaddr->ident)) {
-		/* C-bit is set in the locator indicating that this
-		 * is a locator being translated to a SIR address.
-		 * Perform (receiver) checksum-neutral translation.
-		 */
-		if (!set_csum_neutral)
-			ila_csum_do_neutral(iaddr, p);
-	} else {
-		switch (p->csum_mode) {
-		case ILA_CSUM_ADJUST_TRANSPORT:
-			ila_csum_adjust_transport(skb, p);
-			break;
-		case ILA_CSUM_NEUTRAL_MAP:
-			ila_csum_do_neutral(iaddr, p);
-			break;
-		case ILA_CSUM_NO_ACTION:
+	switch (p->csum_mode) {
+	case ILA_CSUM_ADJUST_TRANSPORT:
+		ila_csum_adjust_transport(skb, p);
+		break;
+	case ILA_CSUM_NEUTRAL_MAP:
+		if (sir2ila) {
+			if (WARN_ON(ila_csum_neutral_set(iaddr->ident))) {
+				/* Checksum flag should never be
+				 * set in a formatted SIR address.
+				 */
+				break;
+			}
+		} else if (!ila_csum_neutral_set(iaddr->ident)) {
+			/* ILA to SIR translation and C-bit isn't
+			 * set so we're good.
+			 */
 			break;
 		}
+		ila_csum_do_neutral_fmt(iaddr, p);
+		break;
+	case ILA_CSUM_NEUTRAL_MAP_AUTO:
+		ila_csum_do_neutral_nofmt(iaddr, p);
+		break;
+	case ILA_CSUM_NO_ACTION:
+		break;
 	}
 
 	/* Now change destination address */
diff --git a/net/ipv6/ila/ila_lwt.c b/net/ipv6/ila/ila_lwt.c
index 0c02a09bc351..92269b85281e 100644
--- a/net/ipv6/ila/ila_lwt.c
+++ b/net/ipv6/ila/ila_lwt.c
@@ -126,6 +126,7 @@ static int ila_build_state(struct nlattr *nla,
 	struct lwtunnel_state *newts;
 	const struct fib6_config *cfg6 = cfg;
 	struct ila_addr *iaddr;
+	u8 csum_mode = ILA_CSUM_NO_ACTION;
 	int ret;
 
 	if (family != AF_INET6)
@@ -138,15 +139,6 @@ static int ila_build_state(struct nlattr *nla,
 		return -EINVAL;
 	}
 
-	iaddr = (struct ila_addr *)&cfg6->fc_dst;
-
-	if (!ila_addr_is_ila(iaddr) || ila_csum_neutral_set(iaddr->ident)) {
-		/* Don't allow translation for a non-ILA address or checksum
-		 * neutral flag to be set.
-		 */
-		return -EINVAL;
-	}
-
 	ret = nla_parse_nested(tb, ILA_ATTR_MAX, nla, ila_nl_policy, extack);
 	if (ret < 0)
 		return ret;
@@ -154,6 +146,19 @@ static int ila_build_state(struct nlattr *nla,
 	if (!tb[ILA_ATTR_LOCATOR])
 		return -EINVAL;
 
+	iaddr = (struct ila_addr *)&cfg6->fc_dst;
+
+	if (tb[ILA_ATTR_CSUM_MODE])
+		csum_mode = nla_get_u8(tb[ILA_ATTR_CSUM_MODE]);
+
+	if (csum_mode == ILA_CSUM_NEUTRAL_MAP &&
+	    ila_csum_neutral_set(iaddr->ident)) {
+		/* Don't allow translation if checksum neutral bit is
+		 * configured and it's set in the SIR address.
+		 */
+		return -EINVAL;
+	}
+
 	newts = lwtunnel_state_alloc(sizeof(*ilwt));
 	if (!newts)
 		return -ENOMEM;
@@ -167,17 +172,13 @@ static int ila_build_state(struct nlattr *nla,
 
 	p = ila_params_lwtunnel(newts);
 
+	p->csum_mode = csum_mode;
 	p->locator.v64 = (__force __be64)nla_get_u64(tb[ILA_ATTR_LOCATOR]);
 
 	/* Precompute checksum difference for translation since we
 	 * know both the old locator and the new one.
 	 */
 	p->locator_match = iaddr->loc;
-	p->csum_diff = compute_csum_diff8(
-		(__be32 *)&p->locator_match, (__be32 *)&p->locator);
-
-	if (tb[ILA_ATTR_CSUM_MODE])
-		p->csum_mode = nla_get_u8(tb[ILA_ATTR_CSUM_MODE]);
 
 	ila_init_saved_csum(p);
 
diff --git a/net/ipv6/ila/ila_xlat.c b/net/ipv6/ila/ila_xlat.c
index 5bd419c1abc8..b8577d8bfab5 100644
--- a/net/ipv6/ila/ila_xlat.c
+++ b/net/ipv6/ila/ila_xlat.c
@@ -137,6 +137,8 @@ static int parse_nl_config(struct genl_info *info,
 
 	if (info->attrs[ILA_ATTR_CSUM_MODE])
 		xp->ip.csum_mode = nla_get_u8(info->attrs[ILA_ATTR_CSUM_MODE]);
+	else
+		xp->ip.csum_mode = ILA_CSUM_NO_ACTION;
 
 	if (info->attrs[ILA_ATTR_IFINDEX])
 		xp->ifindex = nla_get_s32(info->attrs[ILA_ATTR_IFINDEX]);
@@ -197,7 +199,7 @@ static void ila_free_cb(void *ptr, void *arg)
 	}
 }
 
-static int ila_xlat_addr(struct sk_buff *skb, bool set_csum_neutral);
+static int ila_xlat_addr(struct sk_buff *skb, bool sir2ila);
 
 static unsigned int
 ila_nf_input(void *priv,
@@ -395,7 +397,7 @@ static int ila_fill_info(struct ila_map *ila, struct sk_buff *msg)
 			      (__force u64)ila->xp.ip.locator_match.v64,
 			      ILA_ATTR_PAD) ||
 	    nla_put_s32(msg, ILA_ATTR_IFINDEX, ila->xp.ifindex) ||
-	    nla_put_u32(msg, ILA_ATTR_CSUM_MODE, ila->xp.ip.csum_mode))
+	    nla_put_u8(msg, ILA_ATTR_CSUM_MODE, ila->xp.ip.csum_mode))
 		return -1;
 
 	return 0;
@@ -606,7 +608,7 @@ static struct pernet_operations ila_net_ops = {
 	.size = sizeof(struct ila_net),
 };
 
-static int ila_xlat_addr(struct sk_buff *skb, bool set_csum_neutral)
+static int ila_xlat_addr(struct sk_buff *skb, bool sir2ila)
 {
 	struct ila_map *ila;
 	struct ipv6hdr *ip6h = ipv6_hdr(skb);
@@ -625,7 +627,7 @@ static int ila_xlat_addr(struct sk_buff *skb, bool set_csum_neutral)
 
 	ila = ila_lookup_wildcards(iaddr, skb->dev->ifindex, ilan);
 	if (ila)
-		ila_update_ipv6_locator(skb, &ila->xp.ip, set_csum_neutral);
+		ila_update_ipv6_locator(skb, &ila->xp.ip, sir2ila);
 
 	rcu_read_unlock();
 
-- 
2.11.0

[PATCH net-next 3/4] ila: allow configuraiton of identifier type

[Tom Herbert]

Allow identifier to be explicitly configured for a mapping.
This can either be one of the identifier types specified in the
ILA draft or a value of ILA_ATYPE_USE_FORMAT which means the
identifier type is inferred from the identifier type field.
If a value other than ILA_ATYPE_USE_FORMAT is set for a
mapping then it is assumed that the identifier type field is
not present in an identifier.

Signed-off-by: Tom Herbert <tom@quantonium.net>
---
 include/uapi/linux/ila.h | 13 +++++++++++++
 net/ipv6/ila/ila.h       | 12 +-----------
 net/ipv6/ila/ila_lwt.c   | 37 +++++++++++++++++++++++++++++++++++++
 net/ipv6/ila/ila_xlat.c  | 18 +++++++++++++-----
 4 files changed, 64 insertions(+), 16 deletions(-)

diff --git a/include/uapi/linux/ila.h b/include/uapi/linux/ila.h
index 0132b14a556f..de88b2c7ca37 100644
--- a/include/uapi/linux/ila.h
+++ b/include/uapi/linux/ila.h
@@ -16,6 +16,7 @@ enum {
 	ILA_ATTR_DIR,				/* u32 */
 	ILA_ATTR_PAD,
 	ILA_ATTR_CSUM_MODE,			/* u8 */
+	ILA_ATTR_IDENT_TYPE,			/* u8 */
 
 	__ILA_ATTR_MAX,
 };
@@ -43,4 +44,16 @@ enum {
 	ILA_CSUM_NEUTRAL_MAP_AUTO,
 };
 
+enum {
+	ILA_ATYPE_IID = 0,
+	ILA_ATYPE_LUID,
+	ILA_ATYPE_VIRT_V4,
+	ILA_ATYPE_VIRT_UNI_V6,
+	ILA_ATYPE_VIRT_MULTI_V6,
+	ILA_ATYPE_NONLOCAL_ADDR,
+	ILA_ATYPE_RSVD_1,
+	ILA_ATYPE_RSVD_2,
+
+	ILA_ATYPE_USE_FORMAT = 32, /* Get type from type field in identifier */
+};
 #endif /* _UAPI_LINUX_ILA_H */
diff --git a/net/ipv6/ila/ila.h b/net/ipv6/ila/ila.h
index e0170f62bc39..3c7a11b62334 100644
--- a/net/ipv6/ila/ila.h
+++ b/net/ipv6/ila/ila.h
@@ -55,17 +55,6 @@ struct ila_identifier {
 	};
 };
 
-enum {
-	ILA_ATYPE_IID = 0,
-	ILA_ATYPE_LUID,
-	ILA_ATYPE_VIRT_V4,
-	ILA_ATYPE_VIRT_UNI_V6,
-	ILA_ATYPE_VIRT_MULTI_V6,
-	ILA_ATYPE_RSVD_1,
-	ILA_ATYPE_RSVD_2,
-	ILA_ATYPE_RSVD_3,
-};
-
 #define CSUM_NEUTRAL_FLAG	htonl(0x10000000)
 
 struct ila_addr {
@@ -93,6 +82,7 @@ struct ila_params {
 	struct ila_locator locator_match;
 	__wsum csum_diff;
 	u8 csum_mode;
+	u8 ident_type;
 };
 
 static inline __wsum compute_csum_diff8(const __be32 *from, const __be32 *to)
diff --git a/net/ipv6/ila/ila_lwt.c b/net/ipv6/ila/ila_lwt.c
index 92269b85281e..291d591a06c0 100644
--- a/net/ipv6/ila/ila_lwt.c
+++ b/net/ipv6/ila/ila_lwt.c
@@ -113,6 +113,7 @@ static int ila_input(struct sk_buff *skb)
 static const struct nla_policy ila_nl_policy[ILA_ATTR_MAX + 1] = {
 	[ILA_ATTR_LOCATOR] = { .type = NLA_U64, },
 	[ILA_ATTR_CSUM_MODE] = { .type = NLA_U8, },
+	[ILA_ATTR_IDENT_TYPE] = { .type = NLA_U8, },
 };
 
 static int ila_build_state(struct nlattr *nla,
@@ -126,7 +127,9 @@ static int ila_build_state(struct nlattr *nla,
 	struct lwtunnel_state *newts;
 	const struct fib6_config *cfg6 = cfg;
 	struct ila_addr *iaddr;
+	u8 ident_type = ILA_ATYPE_USE_FORMAT;
 	u8 csum_mode = ILA_CSUM_NO_ACTION;
+	u8 eff_ident_type;
 	int ret;
 
 	if (family != AF_INET6)
@@ -148,6 +151,34 @@ static int ila_build_state(struct nlattr *nla,
 
 	iaddr = (struct ila_addr *)&cfg6->fc_dst;
 
+	if (tb[ILA_ATTR_IDENT_TYPE])
+		ident_type = nla_get_u8(tb[ILA_ATTR_IDENT_TYPE]);
+
+	if (ident_type == ILA_ATYPE_USE_FORMAT) {
+		/* Infer identifier type from type field in formatted
+		 * identifier.
+		 */
+
+		eff_ident_type = iaddr->ident.type;
+	} else {
+		eff_ident_type = ident_type;
+	}
+
+	switch (eff_ident_type) {
+	case ILA_ATYPE_IID:
+		/* Don't allow ILA for IID type */
+		return -EINVAL;
+	case ILA_ATYPE_LUID:
+		break;
+	case ILA_ATYPE_VIRT_V4:
+	case ILA_ATYPE_VIRT_UNI_V6:
+	case ILA_ATYPE_VIRT_MULTI_V6:
+	case ILA_ATYPE_NONLOCAL_ADDR:
+		/* These ILA formats are not supported yet. */
+	default:
+		return -EINVAL;
+	}
+
 	if (tb[ILA_ATTR_CSUM_MODE])
 		csum_mode = nla_get_u8(tb[ILA_ATTR_CSUM_MODE]);
 
@@ -173,6 +204,7 @@ static int ila_build_state(struct nlattr *nla,
 	p = ila_params_lwtunnel(newts);
 
 	p->csum_mode = csum_mode;
+	p->ident_type = ident_type;
 	p->locator.v64 = (__force __be64)nla_get_u64(tb[ILA_ATTR_LOCATOR]);
 
 	/* Precompute checksum difference for translation since we
@@ -207,9 +239,13 @@ static int ila_fill_encap_info(struct sk_buff *skb,
 	if (nla_put_u64_64bit(skb, ILA_ATTR_LOCATOR, (__force u64)p->locator.v64,
 			      ILA_ATTR_PAD))
 		goto nla_put_failure;
+
 	if (nla_put_u8(skb, ILA_ATTR_CSUM_MODE, (__force u8)p->csum_mode))
 		goto nla_put_failure;
 
+	if (nla_put_u8(skb, ILA_ATTR_IDENT_TYPE, (__force u8)p->ident_type))
+		goto nla_put_failure;
+
 	return 0;
 
 nla_put_failure:
@@ -220,6 +256,7 @@ static int ila_encap_nlsize(struct lwtunnel_state *lwtstate)
 {
 	return nla_total_size_64bit(sizeof(u64)) + /* ILA_ATTR_LOCATOR */
 	       nla_total_size(sizeof(u8)) +        /* ILA_ATTR_CSUM_MODE */
+	       nla_total_size(sizeof(u8)) +        /* ILA_ATTR_IDENT_TYPE */
 	       0;
 }
 
diff --git a/net/ipv6/ila/ila_xlat.c b/net/ipv6/ila/ila_xlat.c
index b8577d8bfab5..9f334e65250c 100644
--- a/net/ipv6/ila/ila_xlat.c
+++ b/net/ipv6/ila/ila_xlat.c
@@ -120,6 +120,7 @@ static const struct nla_policy ila_nl_policy[ILA_ATTR_MAX + 1] = {
 	[ILA_ATTR_LOCATOR_MATCH] = { .type = NLA_U64, },
 	[ILA_ATTR_IFINDEX] = { .type = NLA_U32, },
 	[ILA_ATTR_CSUM_MODE] = { .type = NLA_U8, },
+	[ILA_ATTR_IDENT_TYPE] = { .type = NLA_U8, },
 };
 
 static int parse_nl_config(struct genl_info *info,
@@ -140,6 +141,12 @@ static int parse_nl_config(struct genl_info *info,
 	else
 		xp->ip.csum_mode = ILA_CSUM_NO_ACTION;
 
+	if (info->attrs[ILA_ATTR_IDENT_TYPE])
+		xp->ip.ident_type = nla_get_u8(
+				info->attrs[ILA_ATTR_IDENT_TYPE]);
+	else
+		xp->ip.ident_type = ILA_ATYPE_USE_FORMAT;
+
 	if (info->attrs[ILA_ATTR_IFINDEX])
 		xp->ifindex = nla_get_s32(info->attrs[ILA_ATTR_IFINDEX]);
 
@@ -397,7 +404,8 @@ static int ila_fill_info(struct ila_map *ila, struct sk_buff *msg)
 			      (__force u64)ila->xp.ip.locator_match.v64,
 			      ILA_ATTR_PAD) ||
 	    nla_put_s32(msg, ILA_ATTR_IFINDEX, ila->xp.ifindex) ||
-	    nla_put_u8(msg, ILA_ATTR_CSUM_MODE, ila->xp.ip.csum_mode))
+	    nla_put_u8(msg, ILA_ATTR_CSUM_MODE, ila->xp.ip.csum_mode) ||
+	    nla_put_u8(msg, ILA_ATTR_IDENT_TYPE, ila->xp.ip.ident_type))
 		return -1;
 
 	return 0;
@@ -618,10 +626,10 @@ static int ila_xlat_addr(struct sk_buff *skb, bool sir2ila)
 
 	/* Assumes skb contains a valid IPv6 header that is pulled */
 
-	if (!ila_addr_is_ila(iaddr)) {
-		/* Type indicates this is not an ILA address */
-		return 0;
-	}
+	/* No check here that ILA type in the mapping matches what is in the
+	 * address. We assume that whatever sender gaves us can be translated.
+	 * The checksum mode however is relevant.
+	 */
 
 	rcu_read_lock();
 
-- 
2.11.0

[PATCH net-next 4/4] ila: Add ila.txt

[Tom Herbert]

Add documenation for kernel ILA. This describes ILA, features,
configuration gives some examples.

Signed-off-by: Tom Herbert <tom@quantonium.net>
---
 Documentation/networking/ila.txt | 286 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 286 insertions(+)
 create mode 100644 Documentation/networking/ila.txt

diff --git a/Documentation/networking/ila.txt b/Documentation/networking/ila.txt
new file mode 100644
index 000000000000..e9923218cd99
--- /dev/null
+++ b/Documentation/networking/ila.txt
@@ -0,0 +1,286 @@
+Identifier Locator Addressing (ILA)
+
+
+Introduction
+============
+
+Identifier-locator addressing (ILA) is a technique used with IPv6 that
+differentiates between location and identity of a network node. Part of an
+address expresses the immutable identity of the node, and another part
+indicates the location of the node which can be dynamic. Identifier-locator
+addressing can be used to efficiently implement overlay networks for
+network virtualization as well as solutions for use cases in mobility.
+
+ILA can be thought of as means to implement an overlay network without
+encapsulation. This is accomplished by performing network address
+translation on destination addresses as a packet traverses a network. To
+the network, an ILA translated packet appears to be no different than any
+other IPv6 packet. For instance, if the transport protocol is TCP then an
+ILA translated packet looks like just another TCP/IPv6 packet. The
+advantage of this is that ILA is transparent to the network so that
+optimizations in the network, such as ECMP, RSS, GRO, GSO, etc., just work.
+
+The ILA protocol is described in Internet-Draft draft-herbert-intarea-ila.
+
+
+ILA terminology
+===============
+
+  - Identifier	A number that identifies an addressable node in the network
+		independent of its location. ILA identifiers are sixty-four
+		bit values.
+
+  - Locator	A network prefix that routes to a physical host. Locators
+		provide the topological location of an addressed node. ILA
+		locators are sixty-four bit prefixes.
+
+  - ILA mapping
+		A mapping of an ILA identifier to a locator (or to a
+		locator and meta data). An ILA domain maintains a database
+		that contains mappings for all destinations in the domain.
+
+  - SIR address
+		An IPv6 address composed of a SIR prefix (upper sixty-
+		four bits) and an identifier (lower sixty-four bits).
+		SIR addresses are visible to applications and provide a
+		means for them to address nodes independent of their
+		location.
+
+  - ILA address
+		An IPv6 address composed of a locator (upper sixty-four
+		bits) and an identifier (low order sixty-four bits). ILA
+		addresses are never visible to an application.
+
+  - ILA host	An end host that is capable of performing ILA translations
+		on transmit or receive.
+
+  - ILA router	A network node that performs ILA translation and forwarding
+		of translated packets.
+
+  - ILA forwarding cache
+		A type of ILA router that only maintains a working set
+		cache of mappings.
+
+  - ILA node	A network node capable of performing ILA translations. This
+		can be an ILA router, ILA forwarding cache, or ILA host.
+
+
+Operation
+=========
+
+There are two fundamental operations with ILA:
+
+  - Translate a SIR address to an ILA address. This is performed on ingress
+    to an ILA overlay.
+
+  - Translate an ILA address to a SIR address. This is performed on egress
+    from the ILA overlay.
+
+ILA can be deployed either on end hosts or intermediate devices in the
+network; these are provided by "ILA hosts" and "ILA routers" respectively.
+Configuration and datapath for these two points of deployment is somewhat
+different.
+
+The diagram below illustrates the flow of packets through ILA as well
+as showing ILA hosts and routers.
+
+    +--------+                                                +--------+
+    | Host A +-+                                         +--->| Host B |
+    |        | |              (2) ILA                   (')   |        |
+    +--------+ |            ...addressed....           (   )  +--------+
+               V  +---+--+  .  packet      .  +---+--+  (_)
+   (1) SIR     |  | ILA  |----->-------->---->| ILA  |   |   (3) SIR
+    addressed  +->|router|  .              .  |router|->-+    addressed
+    packet        +---+--+  .     IPv6     .  +---+--+        packet
+                   /        .    Network   .
+                  /         .              .   +--+-++--------+
+    +--------+   /          .              .   |ILA ||  Host  |
+    |  Host  +--+           .              .- -|host||        |
+    |        |              .              .   +--+-++--------+
+    +--------+              ................
+
+
+Transport checksum handling
+===========================
+
+When an address is translated by ILA, an encapsulated transport checksum
+that includes the translated address in a pseudo header may be rendered
+incorrect on the wire. This is a problem for intermediate devices,
+including checksum offload in NICs, that process the checksum. There are
+three options to deal with this:
+
+- no action	Allow the checksum to be incorrect on the wire. Before
+		a receiver verifies a checksum the ILA to SIR address
+		translation must be done.
+
+- adjust transport checksum
+		When ILA translation is performed the packet is parsed
+		and if a transport layer checksum is found then it is
+		adjusted to reflect the correct checksum per the
+		translated address.
+
+- checksum neutral mapping
+		When an address is translated the difference can be offset
+		elsewhere in a part of the packet that is covered by the
+		the checksum. The low order sixteen bits of the identifier
+		are used. This method is preferred since it doesn't require
+		parsing a packet beyond the IP header and in most cases the
+		adjustment can be precomputed and saved with the mapping.
+
+Note that the checksum neutral adjustment affects the low order sixteen
+bits of the identifier. When ILA to SIR address translation is done on
+egress the low order bits are restored to the original value which
+restores the identifier as it was originally sent.
+
+
+Identifier types
+================
+
+ILA defines different types of identifiers for different use cases.
+
+The defined types are:
+
+      0: interface identifier
+
+      1: locally unique identifier
+
+      2: virtual networking identifier for IPv4 address
+
+      3: virtual networking identifier for IPv6 unicast address
+
+      4: virtual networking identifier for IPv6 multicast address
+
+      5: non-local address identifier
+
+In the current implementation of kernel ILA only locally unique identifiers
+(LUID) are supported. LUID allows for a generic, unformatted 64 bit
+identifier.
+
+
+Identifier formats
+==================
+
+Kernel ILA supports two optional fields in an identifier for formatting:
+"C-bit" and "identifier type". The presence of these fields is determined
+by configuration as demonstrated below.
+
+If the identifier type is present it occupies the three highest order
+bits of an identifier. The possible values are given in the above list.
+
+If the C-bit is present,  this is used as an indication that checksum
+neutral mapping has been done. The C-bit can only be set in an
+ILA address, never a SIR address.
+
+In the simplest format the identifier types, C-bit, and checksum
+adjustment value are not present so an identifier is considered an
+unstructured sixty-four bit value.
+
+     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     |                            Identifier                         |
+     +                                                               +
+     |                                                               |
+     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+The checksum neutral adjustment may be configured to always be
+present using neutral-map-auto. In this case there is no C-bit, but the
+checksum adjustment is in the low order 16 bits. The identifier is
+still sixty-four bits.
+
+     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     |                            Identifier                         |
+     |                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     |                               |  Checksum-neutral adjustment  |
+     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+The C-bit may used to explicitly indicate that checksum neutral
+mapping has been applied to an ILA address. The format is:
+
+     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     |     |C|                    Identifier                         |
+     |     +-+                       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     |                               |  Checksum-neutral adjustment  |
+     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+The identifier type field may be present to indicate the identifier
+type. If it is not present then the type is inferred based on mapping
+configuration. The checksum neutral adjustment may automatically
+used with the identifier type as illustrated below.
+
+     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     | Type|                      Identifier                         |
+     +-+-+-+                         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     |                               |  Checksum-neutral adjustment  |
+     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+If the identifier type and the C-bit can be present simultaneously so
+the identifier format would be:
+
+     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     | Type|C|                    Identifier                         |
+     +-+-+-+-+                       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     |                               |  Checksum-neutral adjustment  |
+     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+Configuration
+=============
+
+There are two methods to configure ILA mappings. One is by using LWT routes
+and the other is ila_xlat (called from NFHOOK PREROUTING hook). ila_xlat
+is intended to be used in the receive path for ILA hosts .
+
+An ILA router has also been implemented in XDP. Description of that is
+outside the scope of this document.
+
+The usage of for ILA LWT routes is:
+
+ip route add DEST/128 encap ila LOC csum-mode MODE ident-type TYPE via ADDR
+
+Destination (DEST) can either be a SIR address (for an ILA host or ingress
+ILA router) or an ILA address (egress ILA router). LOC is the sixty-four
+bit locator (with format W:X:Y:Z) that overwrites the upper sixty-four
+bits of the destination address.  Checksum MODE is one of "no-action",
+"adj-transport", "neutral-map", and "neutral-map-auto". If neutral-map is
+set then the C-bit will be present. Identifier TYPE one of "luid" or
+"use-format." In the case of use-format, the identifier type field is
+present and the effective type is taken from that.
+
+The usage of ila_xlat is:
+
+ip ila add loc_match MATCH loc LOC csum-mode MODE ident-type TYPE
+
+MATCH indicates the incoming locator that must be matched to apply
+a the translaiton. LOC is the locator that overwrites the upper
+sixty-four bits of the destination address. MODE and TYPE have the
+same meanings as described above.
+
+
+Some examples
+=============
+
+# Configure an ILA route that uses checksum neutral mapping as well
+# as type field. Note that the type field is set in the SIR address
+# (the 2000 implies type is 1 which is LUID).
+ip route add 3333:0:0:1:2000:0:1:87/128 encap ila 2001:0:87:0 \
+     csum-mode neutral-map ident-type use-format
+
+# Configure an ILA LWT route that uses auto checksum neutral mapping
+# (no C-bit) and configure identifier type to be LUID so that the
+# identifier type field will not be present.
+ip route add 3333:0:0:1:2000:0:2:87/128 encap ila 2001:0:87:1 \
+     csum-mode neutral-map-auto ident-type luid
+
+ila_xlat configuration
+
+# Configure an ILA to SIR mapping that matches a locator and overwrites
+# it with a SIR address (3333:0:0:1 in this example). The C-bit and
+# identifier field are used.
+ip ila add loc_match 2001:0:119:0 loc 3333:0:0:1 \
+    csum-mode neutral-map-auto ident-type use-format
+
+# Configure an ILA to SIR mapping where checksum neutral is automatically
+# set without the C-bit and the identifier type is configured to be LUID
+# so that the identifier type field is not present.
+ip ila add loc_match 2001:0:119:0 loc 3333:0:0:1 \
+    csum-mode neutral-map-auto ident-type use-format
+
-- 
2.11.0

Re: [PATCH net-next 0/4] ila: make identifier format optional and other fixes

[David Miller]

From: Tom Herbert <tom@quantonium.net>
Date: Thu,  2 Nov 2017 14:20:54 -0700

> The identifier type and checksum neutral mapping bits are optional
> in identifier formats. This patch set fixes the implementation to
> make them optional and configurable.

Patch #1 is missing a signoff, please respin with that fixed.

Thank you.