From: Florian Westphal <fw@strlen.de>
To: <netfilter-devel@vger.kernel.org>
Cc: Florian Westphal <fw@strlen.de>
Subject: [PATCH nf-next 2/3] netfilter: conntrack: get rid of tuple in helper definitions
Date: Fri, 26 Jun 2026 14:31:30 +0200 [thread overview]
Message-ID: <20260626123131.23096-3-fw@strlen.de> (raw)
In-Reply-To: <20260626123131.23096-1-fw@strlen.de>
Leftover from the days when the kernel did automatic assignment of helpers
based on a pre-registered / well-known-port.
This helper autoassign was removed from the kernel, so all we really
need are the l3 and l4 protocol numbers.
Because helpers can register for UNSPEC (== l3 agnostic), we can also
remove redundant ipv4+ipv6 register requests.
In the broadcast helper, the only remaining consumer of the port number is
removed. AFAICS its not needed either: The expectation is populated from
the control connection reply tuple, so the src port is the original
directions destination (snmp for example).
LLM complains about silent l3num (u16) -> nfproto (u8) truncation,
add a netlink policy validation to reject large NFPROTO values upfront.
Assisted-by: Claude:claude-sonnet-4-6
Signed-off-by: Florian Westphal <fw@strlen.de>
---
include/net/netfilter/nf_conntrack_helper.h | 9 ++++-----
net/netfilter/nf_conntrack_broadcast.c | 2 --
net/netfilter/nf_conntrack_helper.c | 22 +++++++++------------
net/netfilter/nf_conntrack_ovs.c | 6 +++---
net/netfilter/nfnetlink_cthelper.c | 21 ++++++++++----------
5 files changed, 27 insertions(+), 33 deletions(-)
diff --git a/include/net/netfilter/nf_conntrack_helper.h b/include/net/netfilter/nf_conntrack_helper.h
index c761cd8158b2..f3f0c1392e88 100644
--- a/include/net/netfilter/nf_conntrack_helper.h
+++ b/include/net/netfilter/nf_conntrack_helper.h
@@ -43,11 +43,10 @@ struct nf_conntrack_helper {
refcount_t ct_refcnt;
- /* Tuple of things we will help (compared against server response) */
- struct nf_conntrack_tuple tuple;
+ u8 nfproto; /* NFPROTO_*, can be NFPROTO_UNSPEC */
+ u8 l4proto; /* IPPROTO_UDP/TCP */
- /* Function to call when data passes; return verdict, or -1 to
- invalidate. */
+ /* Function to call when data passes; return verdict */
int __rcu (*help)(struct sk_buff *skb, unsigned int protoff,
struct nf_conn *ct,
enum ip_conntrack_info conntrackinfo);
@@ -94,7 +93,7 @@ struct nf_conntrack_helper *nf_conntrack_helper_try_module_get(const char *name,
void nf_conntrack_helper_put(struct nf_conntrack_helper *helper);
void nf_ct_helper_init(struct nf_conntrack_helper *helper,
- u16 l3num, u16 protonum, const char *name,
+ u8 l3num, u16 protonum, const char *name,
u16 default_port, u16 spec_port, u32 id,
const struct nf_conntrack_expect_policy *exp_pol,
u32 expect_class_max,
diff --git a/net/netfilter/nf_conntrack_broadcast.c b/net/netfilter/nf_conntrack_broadcast.c
index bf78828c7549..6ff954f1bfb8 100644
--- a/net/netfilter/nf_conntrack_broadcast.c
+++ b/net/netfilter/nf_conntrack_broadcast.c
@@ -66,8 +66,6 @@ int nf_conntrack_broadcast_help(struct sk_buff *skb,
exp->tuple = ct->tuplehash[IP_CT_DIR_REPLY].tuple;
helper = rcu_dereference(help->helper);
- if (helper)
- exp->tuple.src.u.udp.port = helper->tuple.src.u.udp.port;
exp->mask.src.u3.ip = mask;
exp->mask.src.u.udp.port = htons(0xFFFF);
diff --git a/net/netfilter/nf_conntrack_helper.c b/net/netfilter/nf_conntrack_helper.c
index 5ad5429352a7..b28986100db0 100644
--- a/net/netfilter/nf_conntrack_helper.c
+++ b/net/netfilter/nf_conntrack_helper.c
@@ -66,12 +66,9 @@ __nf_conntrack_helper_find(const char *name, u16 l3num, u8 protonum)
hlist_for_each_entry_rcu(h, &nf_ct_helper_hash[i], hnode) {
if (strcmp(h->name, name))
continue;
-
- if (h->tuple.src.l3num != NFPROTO_UNSPEC &&
- h->tuple.src.l3num != l3num)
+ if (h->nfproto != NFPROTO_UNSPEC && h->nfproto != l3num)
continue;
-
- if (h->tuple.dst.protonum == protonum)
+ if (h->l4proto == protonum)
return h;
}
return NULL;
@@ -388,13 +385,13 @@ int __nf_conntrack_helper_register(struct nf_conntrack_helper *me)
return -EINVAL;
}
- h = helper_hash(me->name, me->tuple.dst.protonum);
+ h = helper_hash(me->name, me->l4proto);
mutex_lock(&nf_ct_helper_mutex);
hlist_for_each_entry(cur, &nf_ct_helper_hash[h], hnode) {
if (!strcmp(cur->name, me->name) &&
- (cur->tuple.src.l3num == NFPROTO_UNSPEC ||
- cur->tuple.src.l3num == me->tuple.src.l3num) &&
- cur->tuple.dst.protonum == me->tuple.dst.protonum) {
+ (cur->nfproto == NFPROTO_UNSPEC ||
+ cur->nfproto == me->nfproto) &&
+ cur->l4proto == me->l4proto) {
ret = -EBUSY;
goto out;
}
@@ -474,7 +471,7 @@ void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me)
EXPORT_SYMBOL_GPL(nf_conntrack_helper_unregister);
void nf_ct_helper_init(struct nf_conntrack_helper *helper,
- u16 l3num, u16 protonum, const char *name,
+ u8 l3num, u16 protonum, const char *name,
u16 default_port, u16 spec_port, u32 id,
const struct nf_conntrack_expect_policy *exp_pol,
u32 expect_class_max,
@@ -487,9 +484,8 @@ void nf_ct_helper_init(struct nf_conntrack_helper *helper,
{
memset(helper, 0, sizeof(*helper));
- helper->tuple.src.l3num = l3num;
- helper->tuple.dst.protonum = protonum;
- helper->tuple.src.u.all = htons(spec_port);
+ helper->nfproto = l3num;
+ helper->l4proto = protonum;
rcu_assign_pointer(helper->help, help);
helper->from_nlattr = from_nlattr;
diff --git a/net/netfilter/nf_conntrack_ovs.c b/net/netfilter/nf_conntrack_ovs.c
index 49d1511e9921..b4085af3ad1c 100644
--- a/net/netfilter/nf_conntrack_ovs.c
+++ b/net/netfilter/nf_conntrack_ovs.c
@@ -31,8 +31,8 @@ int nf_ct_helper(struct sk_buff *skb, struct nf_conn *ct,
if (!helper)
return NF_ACCEPT;
- if (helper->tuple.src.l3num != NFPROTO_UNSPEC &&
- helper->tuple.src.l3num != proto)
+ if (helper->nfproto != NFPROTO_UNSPEC &&
+ helper->nfproto != proto)
return NF_ACCEPT;
switch (proto) {
@@ -60,7 +60,7 @@ int nf_ct_helper(struct sk_buff *skb, struct nf_conn *ct,
return NF_DROP;
}
- if (helper->tuple.dst.protonum != proto)
+ if (helper->l4proto != proto)
return NF_ACCEPT;
helper_cb = rcu_dereference(helper->help);
diff --git a/net/netfilter/nfnetlink_cthelper.c b/net/netfilter/nfnetlink_cthelper.c
index f1460b683d7a..56655cb7fe2a 100644
--- a/net/netfilter/nfnetlink_cthelper.c
+++ b/net/netfilter/nfnetlink_cthelper.c
@@ -67,7 +67,7 @@ nfnl_userspace_cthelper(struct sk_buff *skb, unsigned int protoff,
}
static const struct nla_policy nfnl_cthelper_tuple_pol[NFCTH_TUPLE_MAX+1] = {
- [NFCTH_TUPLE_L3PROTONUM] = { .type = NLA_U16, },
+ [NFCTH_TUPLE_L3PROTONUM] = NLA_POLICY_MAX(NLA_BE16, NFPROTO_IPV6),
[NFCTH_TUPLE_L4PROTONUM] = { .type = NLA_U8, },
};
@@ -254,7 +254,8 @@ nfnl_cthelper_create(const struct nlattr * const tb[],
helper->data_len = size;
helper->flags |= NF_CT_HELPER_F_USERSPACE;
- memcpy(&helper->tuple, tuple, sizeof(struct nf_conntrack_tuple));
+ helper->nfproto = tuple->src.l3num;
+ helper->l4proto = tuple->dst.protonum;
helper->me = THIS_MODULE;
helper->help = nfnl_userspace_cthelper;
@@ -449,8 +450,8 @@ static int nfnl_cthelper_new(struct sk_buff *skb, const struct nfnl_info *info,
if (strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
continue;
- if ((tuple.src.l3num != cur->tuple.src.l3num ||
- tuple.dst.protonum != cur->tuple.dst.protonum))
+ if ((tuple.src.l3num != cur->nfproto ||
+ tuple.dst.protonum != cur->l4proto))
continue;
if (info->nlh->nlmsg_flags & NLM_F_EXCL)
@@ -479,10 +480,10 @@ nfnl_cthelper_dump_tuple(struct sk_buff *skb,
goto nla_put_failure;
if (nla_put_be16(skb, NFCTH_TUPLE_L3PROTONUM,
- htons(helper->tuple.src.l3num)))
+ htons(helper->nfproto)))
goto nla_put_failure;
- if (nla_put_u8(skb, NFCTH_TUPLE_L4PROTONUM, helper->tuple.dst.protonum))
+ if (nla_put_u8(skb, NFCTH_TUPLE_L4PROTONUM, helper->l4proto))
goto nla_put_failure;
nla_nest_end(skb, nest_parms);
@@ -661,8 +662,8 @@ static int nfnl_cthelper_get(struct sk_buff *skb, const struct nfnl_info *info,
continue;
if (tuple_set &&
- (tuple.src.l3num != cur->tuple.src.l3num ||
- tuple.dst.protonum != cur->tuple.dst.protonum))
+ (tuple.src.l3num != cur->nfproto ||
+ tuple.dst.protonum != cur->l4proto))
continue;
skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
@@ -721,8 +722,8 @@ static int nfnl_cthelper_del(struct sk_buff *skb, const struct nfnl_info *info,
continue;
if (tuple_set &&
- (tuple.src.l3num != cur->tuple.src.l3num ||
- tuple.dst.protonum != cur->tuple.dst.protonum))
+ (tuple.src.l3num != cur->nfproto ||
+ tuple.dst.protonum != cur->l4proto))
continue;
found = true;
--
2.53.0
next prev parent reply other threads:[~2026-06-26 12:31 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-26 12:31 [PATCH nf-next 0/3] netfilter: conntrack: remove obsolete module parameters Florian Westphal
2026-06-26 12:31 ` [PATCH nf-next 1/3] netfilter: nf_conntrack_helper: do not hash by tuple Florian Westphal
2026-06-26 12:31 ` Florian Westphal [this message]
2026-06-26 12:31 ` [PATCH nf-next 3/3] netfilter: conntrack: remove obsolete module parameters Florian Westphal
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