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Message-ID: <20240807211331.1081038-7-chopps@chopps.org>
Date: Wed, 7 Aug 2024 17:13:20 -0400
From: Christian Hopps <chopps@...pps.org>
To: devel@...ux-ipsec.org
Cc: Steffen Klassert <steffen.klassert@...unet.com>,
netdev@...r.kernel.org,
Christian Hopps <chopps@...pps.org>,
Christian Hopps <chopps@...n.net>
Subject: [PATCH ipsec-next v9 06/17] xfrm: add mode_cbs module functionality
From: Christian Hopps <chopps@...n.net>
Add a set of callbacks xfrm_mode_cbs to xfrm_state. These callbacks
enable the addition of new xfrm modes, such as IP-TFS to be defined
in modules.
Signed-off-by: Christian Hopps <chopps@...n.net>
---
include/net/xfrm.h | 43 +++++++++++++++++++++++++
net/xfrm/xfrm_device.c | 3 +-
net/xfrm/xfrm_input.c | 18 +++++++++--
net/xfrm/xfrm_output.c | 2 ++
net/xfrm/xfrm_policy.c | 18 +++++++----
net/xfrm/xfrm_state.c | 72 ++++++++++++++++++++++++++++++++++++++++++
net/xfrm/xfrm_user.c | 13 ++++++++
7 files changed, 159 insertions(+), 10 deletions(-)
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 54cef89f6c1e..323e768ce4f3 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -209,6 +209,7 @@ struct xfrm_state {
u16 family;
xfrm_address_t saddr;
int header_len;
+ int enc_hdr_len;
int trailer_len;
u32 extra_flags;
struct xfrm_mark smark;
@@ -299,6 +300,9 @@ struct xfrm_state {
* interpreted by xfrm_type methods. */
void *data;
u8 dir;
+
+ const struct xfrm_mode_cbs *mode_cbs;
+ void *mode_data;
};
static inline struct net *xs_net(struct xfrm_state *x)
@@ -451,6 +455,45 @@ struct xfrm_type_offload {
int xfrm_register_type_offload(const struct xfrm_type_offload *type, unsigned short family);
void xfrm_unregister_type_offload(const struct xfrm_type_offload *type, unsigned short family);
+/**
+ * struct xfrm_mode_cbs - XFRM mode callbacks
+ * @owner: module owner or NULL
+ * @create_state: Add mode specific state to new `xfrm_state *x`
+ * @delete_state: Cleanup mode specific state from `xfrm_state *x`
+ * @user_init: Process mode specific netlink attributes from user
+ * @copy_to_user: Add netlink attributes to `attrs` based on state in `x`
+ * @clone: Copy mode specific values from `orig` to new state `x`
+ * @sa_len: Return space required to store mode specific netlink attributes
+ * @get_inner_mtu: Return avail payload space after removing encap overhead
+ * @input: Process received packet from SA using mode
+ * @output: Output given packet using mode
+ * @prepare_output: Add mode specific encapsulation to packet in skb. On return
+ * `transport_header` should point at ESP header, `network_header` should
+ * point at outer IP header and `mac_header` should opint at the
+ * protocol/nexthdr field of the outer IP.
+ *
+ * One should examine and understand the specific uses of these callbacks in
+ * xfrm for further detail on how and when these functions are called. RTSL.
+ */
+struct xfrm_mode_cbs {
+ struct module *owner;
+ int (*create_state)(struct xfrm_state *x);
+ void (*delete_state)(struct xfrm_state *x);
+ int (*user_init)(struct net *net, struct xfrm_state *x,
+ struct nlattr **attrs,
+ struct netlink_ext_ack *extack);
+ int (*copy_to_user)(struct xfrm_state *x, struct sk_buff *skb);
+ int (*clone)(struct xfrm_state *x, struct xfrm_state *orig);
+ unsigned int (*sa_len)(const struct xfrm_state *x);
+ u32 (*get_inner_mtu)(struct xfrm_state *x, int outer_mtu);
+ int (*input)(struct xfrm_state *x, struct sk_buff *skb);
+ int (*output)(struct net *net, struct sock *sk, struct sk_buff *skb);
+ int (*prepare_output)(struct xfrm_state *x, struct sk_buff *skb);
+};
+
+int xfrm_register_mode_cbs(u8 mode, const struct xfrm_mode_cbs *mode_cbs);
+void xfrm_unregister_mode_cbs(u8 mode);
+
static inline int xfrm_af2proto(unsigned int family)
{
switch(family) {
diff --git a/net/xfrm/xfrm_device.c b/net/xfrm/xfrm_device.c
index 9a44d363ba62..e412e4afb169 100644
--- a/net/xfrm/xfrm_device.c
+++ b/net/xfrm/xfrm_device.c
@@ -42,7 +42,8 @@ static void __xfrm_mode_tunnel_prep(struct xfrm_state *x, struct sk_buff *skb,
skb->transport_header = skb->network_header + hsize;
skb_reset_mac_len(skb);
- pskb_pull(skb, skb->mac_len + x->props.header_len);
+ pskb_pull(skb,
+ skb->mac_len + x->props.header_len - x->props.enc_hdr_len);
}
static void __xfrm_mode_beet_prep(struct xfrm_state *x, struct sk_buff *skb,
diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index 749e7eea99e4..b7b5cda986fb 100644
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -446,6 +446,9 @@ static int xfrm_inner_mode_input(struct xfrm_state *x,
WARN_ON_ONCE(1);
break;
default:
+ if (x->mode_cbs && x->mode_cbs->input)
+ return x->mode_cbs->input(x, skb);
+
WARN_ON_ONCE(1);
break;
}
@@ -453,6 +456,10 @@ static int xfrm_inner_mode_input(struct xfrm_state *x,
return -EOPNOTSUPP;
}
+/* NOTE: encap_type - In addition to the normal (non-negative) values for
+ * encap_type, a negative value of -1 or -2 can be used to resume/restart this
+ * function after a previous invocation early terminated for async operation.
+ */
int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
{
const struct xfrm_state_afinfo *afinfo;
@@ -489,6 +496,10 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
family = x->props.family;
+ /* An encap_type of -2 indicates reconstructed inner packet */
+ if (encap_type == -2)
+ goto resume_decapped;
+
/* An encap_type of -1 indicates async resumption. */
if (encap_type == -1) {
async = 1;
@@ -679,11 +690,14 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
XFRM_MODE_SKB_CB(skb)->protocol = nexthdr;
- if (xfrm_inner_mode_input(x, skb)) {
+ err = xfrm_inner_mode_input(x, skb);
+ if (err == -EINPROGRESS)
+ return 0;
+ else if (err) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);
goto drop;
}
-
+resume_decapped:
if (x->outer_mode.flags & XFRM_MODE_FLAG_TUNNEL) {
decaps = 1;
break;
diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c
index e5722c95b8bb..ef81359e4038 100644
--- a/net/xfrm/xfrm_output.c
+++ b/net/xfrm/xfrm_output.c
@@ -472,6 +472,8 @@ static int xfrm_outer_mode_output(struct xfrm_state *x, struct sk_buff *skb)
WARN_ON_ONCE(1);
break;
default:
+ if (x->mode_cbs && x->mode_cbs->prepare_output)
+ return x->mode_cbs->prepare_output(x, skb);
WARN_ON_ONCE(1);
break;
}
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index c56c61b0c12e..f764b1409175 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -2719,13 +2719,17 @@ static struct dst_entry *xfrm_bundle_create(struct xfrm_policy *policy,
dst1->input = dst_discard;
- rcu_read_lock();
- afinfo = xfrm_state_afinfo_get_rcu(inner_mode->family);
- if (likely(afinfo))
- dst1->output = afinfo->output;
- else
- dst1->output = dst_discard_out;
- rcu_read_unlock();
+ if (xfrm[i]->mode_cbs && xfrm[i]->mode_cbs->output) {
+ dst1->output = xfrm[i]->mode_cbs->output;
+ } else {
+ rcu_read_lock();
+ afinfo = xfrm_state_afinfo_get_rcu(inner_mode->family);
+ if (likely(afinfo))
+ dst1->output = afinfo->output;
+ else
+ dst1->output = dst_discard_out;
+ rcu_read_unlock();
+ }
xdst_prev = xdst;
diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 37478d36a8df..e7b656bb6c0d 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -515,6 +515,60 @@ static const struct xfrm_mode *xfrm_get_mode(unsigned int encap, int family)
return NULL;
}
+static const struct xfrm_mode_cbs __rcu *xfrm_mode_cbs_map[XFRM_MODE_MAX];
+static DEFINE_SPINLOCK(xfrm_mode_cbs_map_lock);
+
+int xfrm_register_mode_cbs(u8 mode, const struct xfrm_mode_cbs *mode_cbs)
+{
+ if (mode >= XFRM_MODE_MAX)
+ return -EINVAL;
+
+ spin_lock_bh(&xfrm_mode_cbs_map_lock);
+ rcu_assign_pointer(xfrm_mode_cbs_map[mode], mode_cbs);
+ spin_unlock_bh(&xfrm_mode_cbs_map_lock);
+
+ return 0;
+}
+EXPORT_SYMBOL(xfrm_register_mode_cbs);
+
+void xfrm_unregister_mode_cbs(u8 mode)
+{
+ if (mode >= XFRM_MODE_MAX)
+ return;
+
+ spin_lock_bh(&xfrm_mode_cbs_map_lock);
+ RCU_INIT_POINTER(xfrm_mode_cbs_map[mode], NULL);
+ spin_unlock_bh(&xfrm_mode_cbs_map_lock);
+ synchronize_rcu();
+}
+EXPORT_SYMBOL(xfrm_unregister_mode_cbs);
+
+static const struct xfrm_mode_cbs *xfrm_get_mode_cbs(u8 mode)
+{
+ const struct xfrm_mode_cbs *cbs;
+ bool try_load = true;
+
+ if (mode >= XFRM_MODE_MAX)
+ return NULL;
+
+retry:
+ rcu_read_lock();
+
+ cbs = rcu_dereference(xfrm_mode_cbs_map[mode]);
+ if (cbs && !try_module_get(cbs->owner))
+ cbs = NULL;
+
+ rcu_read_unlock();
+
+ if (mode == XFRM_MODE_IPTFS && !cbs && try_load) {
+ request_module("xfrm-iptfs");
+ try_load = false;
+ goto retry;
+ }
+
+ return cbs;
+}
+
void xfrm_state_free(struct xfrm_state *x)
{
kmem_cache_free(xfrm_state_cache, x);
@@ -523,6 +577,8 @@ EXPORT_SYMBOL(xfrm_state_free);
static void ___xfrm_state_destroy(struct xfrm_state *x)
{
+ if (x->mode_cbs && x->mode_cbs->delete_state)
+ x->mode_cbs->delete_state(x);
hrtimer_cancel(&x->mtimer);
del_timer_sync(&x->rtimer);
kfree(x->aead);
@@ -680,6 +736,7 @@ struct xfrm_state *xfrm_state_alloc(struct net *net)
x->replay_maxage = 0;
x->replay_maxdiff = 0;
spin_lock_init(&x->lock);
+ x->mode_data = NULL;
}
return x;
}
@@ -1806,6 +1863,12 @@ static struct xfrm_state *xfrm_state_clone(struct xfrm_state *orig,
x->new_mapping_sport = 0;
x->dir = orig->dir;
+ x->mode_cbs = orig->mode_cbs;
+ if (x->mode_cbs && x->mode_cbs->clone) {
+ if (x->mode_cbs->clone(x, orig))
+ goto error;
+ }
+
return x;
error:
@@ -2845,6 +2908,9 @@ u32 xfrm_state_mtu(struct xfrm_state *x, int mtu)
case XFRM_MODE_TUNNEL:
break;
default:
+ if (x->mode_cbs && x->mode_cbs->get_inner_mtu)
+ return x->mode_cbs->get_inner_mtu(x, mtu);
+
WARN_ON_ONCE(1);
break;
}
@@ -2945,6 +3011,12 @@ int __xfrm_init_state(struct xfrm_state *x, bool init_replay, bool offload,
}
}
+ x->mode_cbs = xfrm_get_mode_cbs(x->props.mode);
+ if (x->mode_cbs) {
+ if (x->mode_cbs->create_state)
+ err = x->mode_cbs->create_state(x);
+ module_put(x->mode_cbs->owner);
+ }
error:
return err;
}
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index f6ed019192f3..419bbeea6b20 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -918,6 +918,12 @@ static struct xfrm_state *xfrm_state_construct(struct net *net,
goto error;
}
+ if (x->mode_cbs && x->mode_cbs->user_init) {
+ err = x->mode_cbs->user_init(net, x, attrs, extack);
+ if (err)
+ goto error;
+ }
+
return x;
error:
@@ -1331,6 +1337,10 @@ static int copy_to_user_state_extra(struct xfrm_state *x,
if (ret)
goto out;
}
+ if (x->mode_cbs && x->mode_cbs->copy_to_user)
+ ret = x->mode_cbs->copy_to_user(x, skb);
+ if (ret)
+ goto out;
if (x->mapping_maxage) {
ret = nla_put_u32(skb, XFRMA_MTIMER_THRESH, x->mapping_maxage);
if (ret)
@@ -3540,6 +3550,9 @@ static inline unsigned int xfrm_sa_len(struct xfrm_state *x)
if (x->nat_keepalive_interval)
l += nla_total_size(sizeof(x->nat_keepalive_interval));
+ if (x->mode_cbs && x->mode_cbs->sa_len)
+ l += x->mode_cbs->sa_len(x);
+
return l;
}
--
2.46.0
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