[PATCH net-next v3 1/4] netfilter: conntrack: add shared port and uint parsers for helpers

HACKE-RC
2026-05-03T08:32:43Z

Add nf_ct_helper_parse_uint() for bounded unsigned integer parsing
from an unterminated buffer, and nf_ct_helper_parse_port() which calls
it with max=65535 and rejects port zero. Both helpers are exported so
conntrack protocol helpers can replace ad-hoc simple_strtoul() usage.

Signed-off-by: HACKE-RC <rc@rexion.ai>
---
include/net/netfilter/nf_conntrack_helper.h | 5 +++
net/netfilter/nf_conntrack_helper.c | 39 +++++++++++++++++++++
2 files changed, 44 insertions(+)

diff --git a/include/net/netfilter/nf_conntrack_helper.h b/include/net/netfilter/nf_conntrack_helper.h
index de2f956ab..ab145fcd9 100644
--- a/include/net/netfilter/nf_conntrack_helper.h
+++ b/include/net/netfilter/nf_conntrack_helper.h
@@ -160,6 +160,11 @@ nf_ct_helper_expectfn_find_by_name(const char *name);
struct nf_ct_helper_expectfn *
nf_ct_helper_expectfn_find_by_symbol(const void *symbol);

+int nf_ct_helper_parse_uint(const char *cp, unsigned int len,
+ unsigned long max, unsigned long *val, char **endp);
+int nf_ct_helper_parse_port(const char *cp, unsigned int len,
+ u16 *port, char **endp);
+
extern struct hlist_head *nf_ct_helper_hash;
extern unsigned int nf_ct_helper_hsize;

diff --git a/net/netfilter/nf_conntrack_helper.c b/net/netfilter/nf_conntrack_helper.c
index a715304a5..f6229957c 100644
--- a/net/netfilter/nf_conntrack_helper.c
+++ b/net/netfilter/nf_conntrack_helper.c
@@ -499,6 +499,45 @@ void nf_nat_helper_unregister(struct nf_conntrack_nat_helper *nat)
}
EXPORT_SYMBOL_GPL(nf_nat_helper_unregister);

+int nf_ct_helper_parse_uint(const char *cp, unsigned int len,
+ unsigned long max, unsigned long *val, char **endp)
+{
+ unsigned long result = 0;
+
+ if (!len || *cp < '0' || *cp > '9')
+ return -1;
+
+ while (len > 0 && *cp >= '0' && *cp <= '9') {
+ result = result * 10 + (*cp - '0');
+ if (result > max)
+ return -1;
+ cp++;
+ len--;
+ }
+
+ *val = result;
+ if (endp)
+ *endp = (char *)cp;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(nf_ct_helper_parse_uint);
+
+int nf_ct_helper_parse_port(const char *cp, unsigned int len,
+ u16 *port, char **endp)
+{
+ unsigned long val;
+
+ if (nf_ct_helper_parse_uint(cp, len, 65535, &val, endp))
+ return -1;
+ if (val == 0)
+ return -1;
+
+ *port = val;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(nf_ct_helper_parse_port);
+
int nf_conntrack_helper_init(void)
{
nf_ct_helper_hsize = 1; /* gets rounded up to use one page */
--
2.54.0