Currently the forwarding table records details of explicit port forwards,
but nothing for -[tTuU] auto. That looks a little odd on the debug output,
and will be a problem for future changes.
Extend the forward table to have entries for auto-scanned forwards, using
a new FWD_SCAN flag. For now the mechanism of auto port forwarding isn't
updated, and we can only create a single FWD_SCAN entry per protocol and
direction. We'll better integrate auto scanning with other forward table
mechanics in future.
Signed-off-by: David Gibson
---
conf.c | 31 ++++++++++++++++++++++++++-----
fwd.c | 12 +++++++-----
fwd.h | 2 ++
3 files changed, 35 insertions(+), 10 deletions(-)
diff --git a/conf.c b/conf.c
index b24ab407..36f5d448 100644
--- a/conf.c
+++ b/conf.c
@@ -135,7 +135,7 @@ static int parse_port_range(const char *s, char **endptr,
* @ifname: Listening interface
* @first: First port to forward
* @last: Last port to forward
- * @exclude: Bitmap of ports to exclude
+ * @exclude: Bitmap of ports to exclude (may be NULL)
* @to: Port to translate @first to when forwarding
* @flags: Flags for forwarding entries
*/
@@ -158,11 +158,11 @@ static void conf_ports_range_except(const struct ctx *c, char optname,
}
for (base = first; base <= last; base++) {
- if (bitmap_isset(exclude, base))
+ if (exclude && bitmap_isset(exclude, base))
continue;
for (i = base; i <= last; i++) {
- if (bitmap_isset(exclude, i))
+ if (exclude && bitmap_isset(exclude, i))
break;
if (bitmap_isset(fwd->map, i)) {
@@ -173,10 +173,10 @@ static void conf_ports_range_except(const struct ctx *c, char optname,
bitmap_set(fwd->map, i);
fwd->delta[i] = delta;
- if (optname == 't')
+ if (!(flags & FWD_SCAN) && optname == 't')
ret = tcp_sock_init(c, PIF_HOST, addr, ifname,
i);
- else if (optname == 'u')
+ else if (!(flags & FWD_SCAN) && optname == 'u')
ret = udp_sock_init(c, PIF_HOST, addr, ifname,
i);
else
@@ -2191,6 +2191,27 @@ void conf(struct ctx *c, int argc, char **argv)
if (!c->udp.fwd_out.mode)
c->udp.fwd_out.mode = fwd_default;
+ if (c->tcp.fwd_in.mode == FWD_AUTO) {
+ conf_ports_range_except(c, 't', "auto", &c->tcp.fwd_in,
+ NULL, NULL, 1, NUM_PORTS - 1,
+ NULL, 1, FWD_SCAN);
+ }
+ if (c->tcp.fwd_out.mode == FWD_AUTO) {
+ conf_ports_range_except(c, 'T', "auto", &c->tcp.fwd_out,
+ NULL, "lo", 1, NUM_PORTS - 1,
+ NULL, 1, FWD_SCAN);
+ }
+ if (c->udp.fwd_in.mode == FWD_AUTO) {
+ conf_ports_range_except(c, 'u', "auto", &c->udp.fwd_in,
+ NULL, NULL, 1, NUM_PORTS - 1,
+ NULL, 1, FWD_SCAN);
+ }
+ if (c->udp.fwd_out.mode == FWD_AUTO) {
+ conf_ports_range_except(c, 'U', "auto", &c->udp.fwd_out,
+ NULL, "lo", 1, NUM_PORTS - 1,
+ NULL, 1, FWD_SCAN);
+ }
+
if (!c->quiet)
conf_print(c);
}
diff --git a/fwd.c b/fwd.c
index f4b6c492..4e54f5ce 100644
--- a/fwd.c
+++ b/fwd.c
@@ -331,7 +331,7 @@ void fwd_table_add(struct fwd_ports *tab, uint8_t flags,
in_port_t first, in_port_t last, in_port_t to)
{
/* Flags which can be set from the caller */
- const uint8_t allowed_flags = FWD_WEAK;
+ const uint8_t allowed_flags = FWD_WEAK | FWD_SCAN;
struct fwd_entry *new;
ASSERT(!(flags & ~allowed_flags));
@@ -371,6 +371,7 @@ void fwd_table_print(const struct fwd_ports *tab)
for (i = 0; i < tab->count; i++) {
const struct fwd_entry *fwd = &tab->tab[i];
const char *weak = fwd->flags & FWD_WEAK ? " WEAK" : "";
+ const char *scan = fwd->flags & FWD_SCAN ? " AUTO" : "";
const char *percent = *fwd->ifname ? "%" : "";
char addr[INANY_ADDRSTRLEN] = "*";
@@ -378,13 +379,14 @@ void fwd_table_print(const struct fwd_ports *tab)
inany_ntop(&fwd->addr, addr, sizeof(addr));
if (fwd->first == fwd->last) {
- info(" [%s]%s%s:%hu => %hu %s",
+ info(" [%s]%s%s:%hu => %hu %s%s",
addr, percent, fwd->ifname,
- fwd->first, fwd->to, weak);
+ fwd->first, fwd->to, weak, scan);
} else {
- info(" [%s]%s%s:%hu-%hu => %hu-%hu %s",
+ info(" [%s]%s%s:%hu-%hu => %hu-%hu %s%s",
addr, percent, fwd->ifname, fwd->first, fwd->last,
- fwd->to, fwd->last - fwd->first + fwd->to, weak);
+ fwd->to, fwd->last - fwd->first + fwd->to,
+ weak, scan);
}
}
}
diff --git a/fwd.h b/fwd.h
index 07222f41..7a9bc3ed 100644
--- a/fwd.h
+++ b/fwd.h
@@ -26,6 +26,7 @@ bool fwd_port_is_ephemeral(in_port_t port);
* @flags: Flag mask
* FWD_DUAL_STACK - forward both IPv4 and IPv6 (requires @addr be ::)
* FWD_WEAK - Don't give an error if binds fail for some forwards
+ * FWD_SCAN - Only forward if we scan a listener on the target
*
* FIXME: @addr and @ifname currently ignored for outbound tables
*/
@@ -35,6 +36,7 @@ struct fwd_entry {
in_port_t first, last, to;
#define FWD_DUAL_STACK BIT(0)
#define FWD_WEAK BIT(1)
+#define FWD_SCAN BIT(2)
uint8_t flags;
};
--
2.52.0