icmp: Use -1 to represent "missing" sockets

icmp_id_map[] contains, amongst other things, fds for "ping" sockets
associated with various ICMP echo ids.  However, we only lazily open()
those sockets, so many will be missing.  We currently represent that with
a 0, which isn't great, since that's technically a valid fd.  Use -1
instead.  This does require initializing the fields in icmp_id_map[] but
we already have an obvious place to do that.

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 2024-01-16 16:16:12 +11:00 committed by Stefano Brivio
parent 43713af50e
commit 24badd0acf

10
icmp.c
View file

@ -179,7 +179,7 @@ int icmp_tap_handler(const struct ctx *c, uint8_t pif, int af,
iref.id = id = ntohs(ih->un.echo.id); iref.id = id = ntohs(ih->un.echo.id);
if ((s = icmp_id_map[V4][id].sock) <= 0) { if ((s = icmp_id_map[V4][id].sock) < 0) {
s = sock_l4(c, AF_INET, IPPROTO_ICMP, &c->ip4.addr_out, s = sock_l4(c, AF_INET, IPPROTO_ICMP, &c->ip4.addr_out,
c->ip4.ifname_out, 0, iref.u32); c->ip4.ifname_out, 0, iref.u32);
if (s < 0) if (s < 0)
@ -221,7 +221,7 @@ int icmp_tap_handler(const struct ctx *c, uint8_t pif, int af,
return 1; return 1;
iref.id = id = ntohs(ih->icmp6_identifier); iref.id = id = ntohs(ih->icmp6_identifier);
if ((s = icmp_id_map[V6][id].sock) <= 0) { if ((s = icmp_id_map[V6][id].sock) < 0) {
s = sock_l4(c, AF_INET6, IPPROTO_ICMPV6, s = sock_l4(c, AF_INET6, IPPROTO_ICMPV6,
&c->ip6.addr_out, &c->ip6.addr_out,
c->ip6.ifname_out, 0, iref.u32); c->ip6.ifname_out, 0, iref.u32);
@ -277,7 +277,7 @@ static void icmp_timer_one(const struct ctx *c, int v6, uint16_t id,
epoll_ctl(c->epollfd, EPOLL_CTL_DEL, id_map->sock, NULL); epoll_ctl(c->epollfd, EPOLL_CTL_DEL, id_map->sock, NULL);
close(id_map->sock); close(id_map->sock);
id_map->sock = 0; id_map->sock = -1;
id_map->seq = -1; id_map->seq = -1;
} }
@ -315,6 +315,8 @@ void icmp_init(void)
{ {
unsigned i; unsigned i;
for (i = 0; i < ICMP_NUM_IDS; i++) for (i = 0; i < ICMP_NUM_IDS; i++) {
icmp_id_map[V4][i].seq = icmp_id_map[V6][i].seq = -1; icmp_id_map[V4][i].seq = icmp_id_map[V6][i].seq = -1;
icmp_id_map[V4][i].sock = icmp_id_map[V6][i].sock = -1;
}
} }