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ila: add checksum neutral map auto
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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>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Tom Herbert authored and David S. Miller committed Nov 8, 2017
1 parent 80661e7 commit 84287bb
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Showing 4 changed files with 61 additions and 44 deletions.
1 change: 1 addition & 0 deletions include/uapi/linux/ila.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,7 @@ enum {
ILA_CSUM_ADJUST_TRANSPORT,
ILA_CSUM_NEUTRAL_MAP,
ILA_CSUM_NO_ACTION,
ILA_CSUM_NEUTRAL_MAP_AUTO,
};

#endif /* _UAPI_LINUX_ILA_H */
65 changes: 39 additions & 26 deletions net/ipv6/ila/ila_common.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand All @@ -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:
Expand Down Expand Up @@ -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 */
Expand Down
29 changes: 15 additions & 14 deletions net/ipv6/ila/ila_lwt.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -127,6 +127,7 @@ 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)
Expand All @@ -139,22 +140,26 @@ 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;

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;
Expand All @@ -168,17 +173,13 @@ 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);

Expand Down
10 changes: 6 additions & 4 deletions net/ipv6/ila/ila_xlat.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -138,6 +138,8 @@ 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]);
Expand Down Expand Up @@ -198,7 +200,7 @@ 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,
Expand Down Expand Up @@ -396,7 +398,7 @@ 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;
Expand Down Expand Up @@ -607,7 +609,7 @@ 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);
Expand All @@ -626,7 +628,7 @@ 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();

Expand Down

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