udp uses the udp_tap_map, udp_splice_ns and udp_splice_init tables to keep
track of already opened sockets bound to specific ports. We need a way to
indicate entries where a socket hasn't been opened, but the code isn't
consistent if this is indicated by a 0 or a -1:
* udp_splice_sendfrom() and udp_tap_handler() assume that 0 indicates
an unopened socket
* udp_sock_init() fills in -1 for a failure to open a socket
* udp_timer_one() is somewhere in between, treating only strictly
positive fds as valid
-1 (or, at least, negative) is really the correct choice here, since 0 is
a theoretically valid fd value (if very unlikely in practice). Change to
use that consistently throughout.
The table does need to be initialised to all -1 values before any calls to
udp_sock_init() which can happen from conf_ports(). Because C doesn't make
it easy to statically initialise non zero values in large tables, this does
require a somewhat awkward call to initialise the table from conf(). This
is the best approach I could see for the short term, with any luck it will
go away at some point when those socket tables are replaced by a unified
flow table.
Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au>
---
conf.c | 1 +
udp.c | 26 +++++++++++++++++++++-----
udp.h | 1 +
3 files changed, 23 insertions(+), 5 deletions(-)
diff --git a/conf.c b/conf.c
index a235b31..95b3e4b 100644
--- a/conf.c
+++ b/conf.c
@@ -1740,6 +1740,7 @@ void conf(struct ctx *c, int argc, char **argv)
c->no_map_gw = 1;
/* Inbound port options can be parsed now (after IPv4/IPv6 settings) */
+ udp_portmap_clear();
optind = 1;
do {
name = getopt_long(argc, argv, optstring, options, NULL);
diff --git a/udp.c b/udp.c
index cadf393..a8473e3 100644
--- a/udp.c
+++ b/udp.c
@@ -238,6 +238,20 @@ static struct sockaddr_in6 udp6_localname = {
static struct mmsghdr udp4_mh_splice [UDP_MAX_FRAMES];
static struct mmsghdr udp6_mh_splice [UDP_MAX_FRAMES];
+/**
+ * udp_portmap_clear() - Clear UDP port map before configuration
+ */
+void udp_portmap_clear(void)
+{
+ unsigned i;
+
+ for (i = 0; i < NUM_PORTS; i++) {
+ udp_tap_map[V4][i].sock = udp_tap_map[V6][i].sock = -1;
+ udp_splice_ns[V4][i].sock = udp_splice_ns[V6][i].sock = -1;
+ udp_splice_init[V4][i].sock = udp_splice_init[V6][i].sock = -1;
+ }
+}
+
/**
* udp_invert_portmap() - Compute reverse port translations for return packets
* @fwd: Port forwarding configuration to compute reverse map for
@@ -521,7 +535,7 @@ static void udp_splice_sendfrom(const struct ctx *c, unsigned start,
unsigned n,
if (from_ns) {
src += c->udp.fwd_in.rdelta[src];
s = udp_splice_init[v6][src].sock;
- if (!s && allow_new)
+ if (s < 0 && allow_new)
s = udp_splice_new(c, v6, src, false);
if (s < 0)
@@ -532,7 +546,7 @@ static void udp_splice_sendfrom(const struct ctx *c, unsigned start,
unsigned n,
} else {
src += c->udp.fwd_out.rdelta[src];
s = udp_splice_ns[v6][src].sock;
- if (!s && allow_new) {
+ if (s < 0 && allow_new) {
struct udp_splice_new_ns_arg arg = {
c, v6, src, -1,
};
@@ -844,7 +858,9 @@ int udp_tap_handler(struct ctx *c, int af, const void *saddr, const
void *daddr,
s_in.sin_addr = c->ip4.addr_seen;
}
- if (!(s = udp_tap_map[V4][src].sock)) {
+ debug("UDP from tap src=%hu dst=%hu, s=%d",
+ src, dst, udp_tap_map[V4][src].sock);
+ if ((s = udp_tap_map[V4][src].sock) < 0) {
union udp_epoll_ref uref = { .port = src };
in_addr_t bind_addr = { 0 };
const char *bind_if = NULL;
@@ -894,7 +910,7 @@ int udp_tap_handler(struct ctx *c, int af, const void *saddr, const
void *daddr,
bind_addr = &c->ip6.addr_ll;
}
- if (!(s = udp_tap_map[V6][src].sock)) {
+ if ((s = udp_tap_map[V6][src].sock) < 0) {
union udp_epoll_ref uref = { .v6 = 1, .port = src };
const char *bind_if = NULL;
@@ -1160,7 +1176,7 @@ static void udp_timer_one(struct ctx *c, int v6, enum udp_act_type
type,
return;
}
- if (s > 0) {
+ if (s >= 0) {
epoll_ctl(c->epollfd, EPOLL_CTL_DEL, s, NULL);
close(s);
bitmap_clear(udp_act[v6 ? V6 : V4][type], port);
diff --git a/udp.h b/udp.h
index 7837134..73faf21 100644
--- a/udp.h
+++ b/udp.h
@@ -8,6 +8,7 @@
#define UDP_TIMER_INTERVAL 1000 /* ms */
+void udp_portmap_clear(void);
void udp_sock_handler(const struct ctx *c, union epoll_ref ref, uint32_t events,
const struct timespec *now);
int udp_tap_handler(struct ctx *c, int af, const void *saddr, const void *daddr,
--
2.41.0