[PATCH 1/5] udp: Don't attempt to translate a 0.0.0.0 source address

[David Gibson <david@gibson.dropbear.id.au>]

If an incoming packet has a source address of 0.0.0.0 we translate that to
the gateway address.  This doesn't really make sense, because we have no
way to do a reverse translation for reply packets.

Certain UDP protocols do use an unspecified source address in some
circumstances (e.g. DHCP).  These generally either require no reply, a
multicast reply, or provides a suitable reply address by other means.

In none of those cases does translating it in passt/pasta make sense.  The
best we can really do here is just leave it as is.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 udp.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/udp.c b/udp.c
index 39c59d4..78cb221 100644
--- a/udp.c
+++ b/udp.c
@@ -595,7 +595,6 @@ static size_t udp_update_hdr4(const struct ctx *c, int n, in_port_t dstport,
 	    src_port == 53) {
 		b->iph.saddr = c->ip4.dns_match.s_addr;
 	} else if (IN4_IS_ADDR_LOOPBACK(&b->s_in.sin_addr) ||
-		   IN4_IS_ADDR_UNSPECIFIED(&b->s_in.sin_addr)||
 		   IN4_ARE_ADDR_EQUAL(&b->s_in.sin_addr, &c->ip4.addr_seen)) {
 		b->iph.saddr = c->ip4.gw.s_addr;
 		udp_tap_map[V4][src_port].ts = now->tv_sec;
-- 
@@ -595,7 +595,6 @@ static size_t udp_update_hdr4(const struct ctx *c, int n, in_port_t dstport,
 	    src_port == 53) {
 		b->iph.saddr = c->ip4.dns_match.s_addr;
 	} else if (IN4_IS_ADDR_LOOPBACK(&b->s_in.sin_addr) ||
-		   IN4_IS_ADDR_UNSPECIFIED(&b->s_in.sin_addr)||
 		   IN4_ARE_ADDR_EQUAL(&b->s_in.sin_addr, &c->ip4.addr_seen)) {
 		b->iph.saddr = c->ip4.gw.s_addr;
 		udp_tap_map[V4][src_port].ts = now->tv_sec;
-- 
2.40.1