udp: Small streamline to udp_update_hdr4()

Streamline the logic here slightly, by introducing a 'src' temporary for
brevity.  We also transform the logic for setting/clearing PORT_LOOPBACK.
This makes udp_update_hdr4() more closely match the corresponding logic
from udp_update_udp6().

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
David Gibson 2024-02-28 16:39:27 +11:00 committed by Stefano Brivio
parent bc2d0d381c
commit deea5a8437

17
udp.c
View file

@ -584,6 +584,7 @@ static size_t udp_update_hdr4(const struct ctx *c, int n, in_port_t dstport,
const struct timespec *now)
{
struct udp4_l2_buf_t *b = &udp4_l2_buf[n];
struct in_addr *src;
in_port_t src_port;
size_t ip_len;
@ -592,26 +593,26 @@ static size_t udp_update_hdr4(const struct ctx *c, int n, in_port_t dstport,
b->iph.tot_len = htons(ip_len);
b->iph.daddr = c->ip4.addr_seen.s_addr;
src = &b->s_in.sin_addr;
src_port = ntohs(b->s_in.sin_port);
if (!IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns_match) &&
IN4_ARE_ADDR_EQUAL(&b->s_in.sin_addr, &c->ip4.dns_host) &&
src_port == 53) {
IN4_ARE_ADDR_EQUAL(src, &c->ip4.dns_host) && src_port == 53) {
b->iph.saddr = c->ip4.dns_match.s_addr;
} else if (IN4_IS_ADDR_LOOPBACK(&b->s_in.sin_addr) ||
IN4_ARE_ADDR_EQUAL(&b->s_in.sin_addr, &c->ip4.addr_seen)) {
} else if (IN4_IS_ADDR_LOOPBACK(src) ||
IN4_ARE_ADDR_EQUAL(src, &c->ip4.addr_seen)) {
b->iph.saddr = c->ip4.gw.s_addr;
udp_tap_map[V4][src_port].ts = now->tv_sec;
udp_tap_map[V4][src_port].flags |= PORT_LOCAL;
if (IN4_ARE_ADDR_EQUAL(&b->s_in.sin_addr.s_addr, &c->ip4.addr_seen))
udp_tap_map[V4][src_port].flags &= ~PORT_LOOPBACK;
else
if (IN4_IS_ADDR_LOOPBACK(src))
udp_tap_map[V4][src_port].flags |= PORT_LOOPBACK;
else
udp_tap_map[V4][src_port].flags &= ~PORT_LOOPBACK;
bitmap_set(udp_act[V4][UDP_ACT_TAP], src_port);
} else {
b->iph.saddr = b->s_in.sin_addr.s_addr;
b->iph.saddr = src->s_addr;
}
udp_update_check4(b);