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Message-Id: <20220721134245.2450-10-memxor@gmail.com>
Date: Thu, 21 Jul 2022 15:42:41 +0200
From: Kumar Kartikeya Dwivedi <memxor@...il.com>
To: bpf@...r.kernel.org
Cc: Lorenzo Bianconi <lorenzo@...nel.org>,
Alexei Starovoitov <ast@...nel.org>,
Andrii Nakryiko <andrii@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
Pablo Neira Ayuso <pablo@...filter.org>,
Florian Westphal <fw@...len.de>,
Jesper Dangaard Brouer <brouer@...hat.com>,
Toke Høiland-Jørgensen <toke@...hat.com>,
netdev@...r.kernel.org, netfilter-devel@...r.kernel.org
Subject: [PATCH bpf-next v7 09/13] net: netfilter: Add kfuncs to set and change CT status
From: Lorenzo Bianconi <lorenzo@...nel.org>
Introduce bpf_ct_set_status and bpf_ct_change_status kfunc helpers in
order to set nf_conn field of allocated entry or update nf_conn status
field of existing inserted entry. Use nf_ct_change_status_common to
share the permitted status field changes between netlink and BPF side
by refactoring ctnetlink_change_status.
It is required to introduce two kfuncs taking nf_conn___init and nf_conn
instead of sharing one because KF_TRUSTED_ARGS flag causes strict type
checking. This would disallow passing nf_conn___init to kfunc taking
nf_conn, and vice versa. We cannot remove the KF_TRUSTED_ARGS flag as we
only want to accept refcounted pointers and not e.g. ct->master.
Hence, bpf_ct_set_* kfuncs are meant to be used on allocated CT, and
bpf_ct_change_* kfuncs are meant to be used on inserted or looked up
CT entry.
Signed-off-by: Lorenzo Bianconi <lorenzo@...nel.org>
Co-developed-by: Kumar Kartikeya Dwivedi <memxor@...il.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@...il.com>
---
include/net/netfilter/nf_conntrack_core.h | 2 ++
net/netfilter/nf_conntrack_bpf.c | 32 ++++++++++++++++++
net/netfilter/nf_conntrack_core.c | 40 +++++++++++++++++++++++
net/netfilter/nf_conntrack_netlink.c | 39 ++--------------------
4 files changed, 76 insertions(+), 37 deletions(-)
diff --git a/include/net/netfilter/nf_conntrack_core.h b/include/net/netfilter/nf_conntrack_core.h
index 3b0f7d0eebae..3cd3a6e631aa 100644
--- a/include/net/netfilter/nf_conntrack_core.h
+++ b/include/net/netfilter/nf_conntrack_core.h
@@ -98,6 +98,8 @@ static inline void __nf_ct_set_timeout(struct nf_conn *ct, u64 timeout)
}
int __nf_ct_change_timeout(struct nf_conn *ct, u64 cta_timeout);
+void __nf_ct_change_status(struct nf_conn *ct, unsigned long on, unsigned long off);
+int nf_ct_change_status_common(struct nf_conn *ct, unsigned int status);
#endif
diff --git a/net/netfilter/nf_conntrack_bpf.c b/net/netfilter/nf_conntrack_bpf.c
index b8912e15082f..1cd87b28c9b0 100644
--- a/net/netfilter/nf_conntrack_bpf.c
+++ b/net/netfilter/nf_conntrack_bpf.c
@@ -394,6 +394,36 @@ int bpf_ct_change_timeout(struct nf_conn *nfct, u32 timeout)
return __nf_ct_change_timeout(nfct, msecs_to_jiffies(timeout));
}
+/* bpf_ct_set_status - Set status field of allocated nf_conn
+ *
+ * Set the status field of the newly allocated nf_conn before insertion.
+ * This must be invoked for referenced PTR_TO_BTF_ID to nf_conn___init.
+ *
+ * Parameters:
+ * @nfct - Pointer to referenced nf_conn object, obtained using
+ * bpf_xdp_ct_alloc or bpf_skb_ct_alloc.
+ * @status - New status value.
+ */
+int bpf_ct_set_status(const struct nf_conn___init *nfct, u32 status)
+{
+ return nf_ct_change_status_common((struct nf_conn *)nfct, status);
+}
+
+/* bpf_ct_change_status - Change status of inserted nf_conn
+ *
+ * Change the status field of the provided connection tracking entry.
+ * This must be invoked for referenced PTR_TO_BTF_ID to nf_conn.
+ *
+ * Parameters:
+ * @nfct - Pointer to referenced nf_conn object, obtained using
+ * bpf_ct_insert_entry, bpf_xdp_ct_lookup or bpf_skb_ct_lookup.
+ * @status - New status value.
+ */
+int bpf_ct_change_status(struct nf_conn *nfct, u32 status)
+{
+ return nf_ct_change_status_common(nfct, status);
+}
+
__diag_pop()
BTF_SET8_START(nf_ct_kfunc_set)
@@ -405,6 +435,8 @@ BTF_ID_FLAGS(func, bpf_ct_insert_entry, KF_ACQUIRE | KF_RET_NULL | KF_RELEASE)
BTF_ID_FLAGS(func, bpf_ct_release, KF_RELEASE)
BTF_ID_FLAGS(func, bpf_ct_set_timeout, KF_TRUSTED_ARGS)
BTF_ID_FLAGS(func, bpf_ct_change_timeout, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_ct_set_status, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_ct_change_status, KF_TRUSTED_ARGS)
BTF_SET8_END(nf_ct_kfunc_set)
static const struct btf_kfunc_id_set nf_conntrack_kfunc_set = {
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 572f59a5e936..66a0aa8dbc3b 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -2807,4 +2807,44 @@ int __nf_ct_change_timeout(struct nf_conn *ct, u64 timeout)
}
EXPORT_SYMBOL_GPL(__nf_ct_change_timeout);
+void __nf_ct_change_status(struct nf_conn *ct, unsigned long on, unsigned long off)
+{
+ unsigned int bit;
+
+ /* Ignore these unchangable bits */
+ on &= ~IPS_UNCHANGEABLE_MASK;
+ off &= ~IPS_UNCHANGEABLE_MASK;
+
+ for (bit = 0; bit < __IPS_MAX_BIT; bit++) {
+ if (on & (1 << bit))
+ set_bit(bit, &ct->status);
+ else if (off & (1 << bit))
+ clear_bit(bit, &ct->status);
+ }
+}
+EXPORT_SYMBOL_GPL(__nf_ct_change_status);
+
+int nf_ct_change_status_common(struct nf_conn *ct, unsigned int status)
+{
+ unsigned long d;
+
+ d = ct->status ^ status;
+
+ if (d & (IPS_EXPECTED|IPS_CONFIRMED|IPS_DYING))
+ /* unchangeable */
+ return -EBUSY;
+
+ if (d & IPS_SEEN_REPLY && !(status & IPS_SEEN_REPLY))
+ /* SEEN_REPLY bit can only be set */
+ return -EBUSY;
+
+ if (d & IPS_ASSURED && !(status & IPS_ASSURED))
+ /* ASSURED bit can only be set */
+ return -EBUSY;
+
+ __nf_ct_change_status(ct, status, 0);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(nf_ct_change_status_common);
+
#endif
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index b1de07c73845..e02832ef9b9f 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -1890,45 +1890,10 @@ ctnetlink_parse_nat_setup(struct nf_conn *ct,
}
#endif
-static void
-__ctnetlink_change_status(struct nf_conn *ct, unsigned long on,
- unsigned long off)
-{
- unsigned int bit;
-
- /* Ignore these unchangable bits */
- on &= ~IPS_UNCHANGEABLE_MASK;
- off &= ~IPS_UNCHANGEABLE_MASK;
-
- for (bit = 0; bit < __IPS_MAX_BIT; bit++) {
- if (on & (1 << bit))
- set_bit(bit, &ct->status);
- else if (off & (1 << bit))
- clear_bit(bit, &ct->status);
- }
-}
-
static int
ctnetlink_change_status(struct nf_conn *ct, const struct nlattr * const cda[])
{
- unsigned long d;
- unsigned int status = ntohl(nla_get_be32(cda[CTA_STATUS]));
- d = ct->status ^ status;
-
- if (d & (IPS_EXPECTED|IPS_CONFIRMED|IPS_DYING))
- /* unchangeable */
- return -EBUSY;
-
- if (d & IPS_SEEN_REPLY && !(status & IPS_SEEN_REPLY))
- /* SEEN_REPLY bit can only be set */
- return -EBUSY;
-
- if (d & IPS_ASSURED && !(status & IPS_ASSURED))
- /* ASSURED bit can only be set */
- return -EBUSY;
-
- __ctnetlink_change_status(ct, status, 0);
- return 0;
+ return nf_ct_change_status_common(ct, ntohl(nla_get_be32(cda[CTA_STATUS])));
}
static int
@@ -2825,7 +2790,7 @@ ctnetlink_update_status(struct nf_conn *ct, const struct nlattr * const cda[])
* unchangeable bits but do not error out. Also user programs
* are allowed to clear the bits that they are allowed to change.
*/
- __ctnetlink_change_status(ct, status, ~status);
+ __nf_ct_change_status(ct, status, ~status);
return 0;
}
--
2.34.1
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