xfrm: allow to avoid copying DSCP during encapsulation
By default, DSCP is copying during encapsulation.
Copying the DSCP in IPsec tunneling may be a bit dangerous because packets with
different DSCP may get reordered relative to each other in the network and then
dropped by the remote IPsec GW if the reordering becomes too big compared to the
replay window.
It is possible to avoid this copy with netfilter rules, but it's very convenient
to be able to configure it for each SA directly.
This patch adds a toogle for this purpose. By default, it's not set to maintain
backward compatibility.
Field flags in struct xfrm_usersa_info is full, hence I add a new attribute.
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 24c8886..ae16531 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -162,6 +162,7 @@
xfrm_address_t saddr;
int header_len;
int trailer_len;
+ u32 extra_flags;
} props;
struct xfrm_lifetime_cfg lft;
diff --git a/include/uapi/linux/xfrm.h b/include/uapi/linux/xfrm.h
index 28e493b..a8cd6a4 100644
--- a/include/uapi/linux/xfrm.h
+++ b/include/uapi/linux/xfrm.h
@@ -297,6 +297,7 @@
XFRMA_MARK, /* struct xfrm_mark */
XFRMA_TFCPAD, /* __u32 */
XFRMA_REPLAY_ESN_VAL, /* struct xfrm_replay_esn */
+ XFRMA_SA_EXTRA_FLAGS, /* __u32 */
__XFRMA_MAX
#define XFRMA_MAX (__XFRMA_MAX - 1)
@@ -367,6 +368,8 @@
#define XFRM_STATE_ESN 128
};
+#define XFRM_SA_XFLAG_DONT_ENCAP_DSCP 1
+
struct xfrm_usersa_id {
xfrm_address_t daddr;
__be32 spi;
diff --git a/net/ipv4/ipcomp.c b/net/ipv4/ipcomp.c
index f01d1b1..59cb8c7 100644
--- a/net/ipv4/ipcomp.c
+++ b/net/ipv4/ipcomp.c
@@ -75,6 +75,7 @@
t->props.mode = x->props.mode;
t->props.saddr.a4 = x->props.saddr.a4;
t->props.flags = x->props.flags;
+ t->props.extra_flags = x->props.extra_flags;
memcpy(&t->mark, &x->mark, sizeof(t->mark));
if (xfrm_init_state(t))
diff --git a/net/ipv4/xfrm4_mode_tunnel.c b/net/ipv4/xfrm4_mode_tunnel.c
index fe5189e..eb1dd4d 100644
--- a/net/ipv4/xfrm4_mode_tunnel.c
+++ b/net/ipv4/xfrm4_mode_tunnel.c
@@ -103,8 +103,12 @@
top_iph->protocol = xfrm_af2proto(skb_dst(skb)->ops->family);
- /* DS disclosed */
- top_iph->tos = INET_ECN_encapsulate(XFRM_MODE_SKB_CB(skb)->tos,
+ /* DS disclosing depends on XFRM_SA_XFLAG_DONT_ENCAP_DSCP */
+ if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
+ top_iph->tos = 0;
+ else
+ top_iph->tos = XFRM_MODE_SKB_CB(skb)->tos;
+ top_iph->tos = INET_ECN_encapsulate(top_iph->tos,
XFRM_MODE_SKB_CB(skb)->tos);
flags = x->props.flags;
diff --git a/net/ipv6/xfrm6_mode_tunnel.c b/net/ipv6/xfrm6_mode_tunnel.c
index 9bf6a74a..4770d51 100644
--- a/net/ipv6/xfrm6_mode_tunnel.c
+++ b/net/ipv6/xfrm6_mode_tunnel.c
@@ -49,8 +49,11 @@
sizeof(top_iph->flow_lbl));
top_iph->nexthdr = xfrm_af2proto(skb_dst(skb)->ops->family);
- dsfield = XFRM_MODE_SKB_CB(skb)->tos;
- dsfield = INET_ECN_encapsulate(dsfield, dsfield);
+ if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
+ dsfield = 0;
+ else
+ dsfield = XFRM_MODE_SKB_CB(skb)->tos;
+ dsfield = INET_ECN_encapsulate(dsfield, XFRM_MODE_SKB_CB(skb)->tos);
if (x->props.flags & XFRM_STATE_NOECN)
dsfield &= ~INET_ECN_MASK;
ipv6_change_dsfield(top_iph, 0, dsfield);
diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 2c341bd..78f66fa 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -1187,6 +1187,7 @@
goto error;
x->props.flags = orig->props.flags;
+ x->props.extra_flags = orig->props.extra_flags;
x->curlft.add_time = orig->curlft.add_time;
x->km.state = orig->km.state;
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index fbd9e6c..204cba1 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -515,6 +515,9 @@
copy_from_user_state(x, p);
+ if (attrs[XFRMA_SA_EXTRA_FLAGS])
+ x->props.extra_flags = nla_get_u32(attrs[XFRMA_SA_EXTRA_FLAGS]);
+
if ((err = attach_aead(&x->aead, &x->props.ealgo,
attrs[XFRMA_ALG_AEAD])))
goto error;
@@ -779,6 +782,13 @@
copy_to_user_state(x, p);
+ if (x->props.extra_flags) {
+ ret = nla_put_u32(skb, XFRMA_SA_EXTRA_FLAGS,
+ x->props.extra_flags);
+ if (ret)
+ goto out;
+ }
+
if (x->coaddr) {
ret = nla_put(skb, XFRMA_COADDR, sizeof(*x->coaddr), x->coaddr);
if (ret)
@@ -2302,6 +2312,7 @@
[XFRMA_MARK] = { .len = sizeof(struct xfrm_mark) },
[XFRMA_TFCPAD] = { .type = NLA_U32 },
[XFRMA_REPLAY_ESN_VAL] = { .len = sizeof(struct xfrm_replay_state_esn) },
+ [XFRMA_SA_EXTRA_FLAGS] = { .type = NLA_U32 },
};
static struct xfrm_link {
@@ -2495,6 +2506,8 @@
x->security->ctx_len);
if (x->coaddr)
l += nla_total_size(sizeof(*x->coaddr));
+ if (x->props.extra_flags)
+ l += nla_total_size(sizeof(x->props.extra_flags));
/* Must count x->lastused as it may become non-zero behind our back. */
l += nla_total_size(sizeof(u64));
