[PATCH 08/18] conf: Pass protocol explicitly to conf_ports_range_except()

David Gibson
2026-04-07T03:16:42Z

Currently conf_ports_range_except() deduces the protocol to use from the
option name. This is correct, but a DRY violation, since we check the
option name at several points in the callchain.

Instead pass the protocol explicitly to conf_ports_range_except() and
conf_ports_spec(), computing it from the option name in conf_ports(). This
is redundant for now, but means the optname and optarg parameters to the
lower-level functions are used only for debugging output and will be
removable in future.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
conf.c | 37 ++++++++++++++++++++-----------------
1 file changed, 20 insertions(+), 17 deletions(-)

diff --git a/conf.c b/conf.c
index a3452bc9..23125d2c 100644
--- a/conf.c
+++ b/conf.c
@@ -134,6 +134,7 @@ static int parse_port_range(const char *s, const char **endptr,
* @optname: Short option name, t, T, u, or U
* @optarg: Option argument (port specification)
* @fwd: Forwarding table to be updated
+ * @proto: Protocol to forward
* @addr: Listening address
* @ifname: Listening interface
* @first: First port to forward
@@ -144,7 +145,7 @@ static int parse_port_range(const char *s, const char **endptr,
*/
static void conf_ports_range_except(const struct ctx *c, char optname,
const char *optarg, struct fwd_table *fwd,
- const union inany_addr *addr,
+ uint8_t proto, const union inany_addr *addr,
const char *ifname,
uint16_t first, uint16_t last,
const uint8_t *exclude, uint16_t to,
@@ -152,17 +153,9 @@ static void conf_ports_range_except(const struct ctx *c, char optname,
{
unsigned delta = to - first;
unsigned base, i;
- uint8_t proto;

assert(first != 0);

- if (optname == 't' || optname == 'T')
- proto = IPPROTO_TCP;
- else if (optname == 'u' || optname == 'U')
- proto = IPPROTO_UDP;
- else
- assert(0);
-
for (base = first; base <= last; base++) {
if (exclude && bitmap_isset(exclude, base))
continue;
@@ -221,13 +214,14 @@ enum fwd_mode {
* @optname: Short option name, t, T, u, or U
* @optarg: Option argument (port specification)
* @fwd: Forwarding table to be updated
+ * @proto: Protocol to forward
* @addr: Listening address for forwarding
* @ifname: Interface name for listening
* @spec: Port range(s) specifier
*/
static void conf_ports_spec(const struct ctx *c,
char optname, const char *optarg,
- struct fwd_table *fwd,
+ struct fwd_table *fwd, uint8_t proto,
const union inany_addr *addr, const char *ifname,
const char *spec)
{
@@ -262,7 +256,7 @@ static void conf_ports_spec(const struct ctx *c,
fwd_port_map_ephemeral(exclude);

conf_ports_range_except(c, optname, optarg, fwd,
- addr, ifname,
+ proto, addr, ifname,
1, NUM_PORTS - 1, exclude,
1, FWD_WEAK);
return;
@@ -299,7 +293,7 @@ static void conf_ports_spec(const struct ctx *c,
}

conf_ports_range_except(c, optname, optarg, fwd,
- addr, ifname,
+ proto, addr, ifname,
orig_range.first, orig_range.last,
exclude,
mapped_range.first, 0);
@@ -323,6 +317,14 @@ static void conf_ports(const struct ctx *c, char optname, const char *optarg,
{
union inany_addr addr_buf = inany_any6, *addr = &addr_buf;
char buf[BUFSIZ], *spec, *ifname = NULL, *p;
+ uint8_t proto;
+
+ if (optname == 't' || optname == 'T')
+ proto = IPPROTO_TCP;
+ else if (optname == 'u' || optname == 'U')
+ proto = IPPROTO_UDP;
+ else
+ assert(0);

if (!strcmp(optarg, "none")) {
if (*mode)
@@ -332,9 +334,9 @@ static void conf_ports(const struct ctx *c, char optname, const char *optarg,
return;
}

- if ((optname == 't' || optname == 'T') && c->no_tcp)
+ if (proto == IPPROTO_TCP && c->no_tcp)
die("TCP port forwarding requested but TCP is disabled");
- if ((optname == 'u' || optname == 'U') && c->no_udp)
+ if (proto == IPPROTO_UDP && c->no_udp)
die("UDP port forwarding requested but UDP is disabled");

if (!strcmp(optarg, "auto")) {
@@ -346,7 +348,8 @@ static void conf_ports(const struct ctx *c, char optname, const char *optarg,

*mode = FWD_MODE_AUTO;

- conf_ports_range_except(c, optname, optarg, fwd, NULL, NULL,
+ conf_ports_range_except(c, optname, optarg, fwd,
+ proto, NULL, NULL,
1, NUM_PORTS - 1, NULL, 1, FWD_SCAN);

return;
@@ -364,7 +367,7 @@ static void conf_ports(const struct ctx *c, char optname, const char *optarg,
fwd_port_map_ephemeral(exclude);

conf_ports_range_except(c, optname, optarg, fwd,
- NULL, NULL,
+ proto, NULL, NULL,
1, NUM_PORTS - 1, exclude,
1, FWD_WEAK);
return;
@@ -438,7 +441,7 @@ static void conf_ports(const struct ctx *c, char optname, const char *optarg,
if ((optname == 'T' || optname == 'U') && !ifname)
ifname = "lo";

- conf_ports_spec(c, optname, optarg, fwd, addr, ifname, spec);
+ conf_ports_spec(c, optname, optarg, fwd, proto, addr, ifname, spec);
return;

mode_conflict:
--
2.53.0