Given that we use just the first valid DNS resolver address
configured, or read from resolv.conf(5) on the host, to forward DNS
queries to, in case --dns-forward is used, we don't need to duplicate
dns[] to dns_send[]:
- rename dns_send[] back to dns[]: those are the resolvers we
advertise to the guest/container
- for forwarding purposes, instead of dns[], use a single field (for
each protocol version): dns_host
- and rename dns_fwd to dns_match, so that it's clear this is the
address we are matching DNS queries against, to decide if they need
to be forwarded
Suggested-by: David Gibson <david(a)gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio(a)redhat.com>
---
conf.c | 76 ++++++++++++++++++++++++--------------------------------
dhcp.c | 5 ++--
dhcpv6.c | 5 ++--
ndp.c | 6 ++---
passt.h | 20 +++++++--------
udp.c | 21 +++++++++-------
6 files changed, 62 insertions(+), 71 deletions(-)
diff --git a/conf.c b/conf.c
index 1adcf83..a995eb7 100644
--- a/conf.c
+++ b/conf.c
@@ -355,11 +355,9 @@ overlap:
*/
static void get_dns(struct ctx *c)
{
- struct in6_addr *dns6_send = &c->ip6.dns_send[0];
- struct in_addr *dns4_send = &c->ip4.dns_send[0];
+ struct in6_addr *dns6 = &c->ip6.dns[0], dns6_tmp;
+ struct in_addr *dns4 = &c->ip4.dns[0], dns4_tmp;
int dns4_set, dns6_set, dnss_set, dns_set, fd;
- struct in6_addr *dns6 = &c->ip6.dns[0];
- struct in_addr *dns4 = &c->ip4.dns[0];
struct fqdn *s = c->dns_search;
struct lineread resolvconf;
int line_len;
@@ -388,49 +386,44 @@ static void get_dns(struct ctx *c)
*end = 0;
if (!dns4_set &&
- dns4 - &c->ip4.dns[0] < ARRAY_SIZE(c->ip4.dns) - 1 &&
- inet_pton(AF_INET, p + 1, dns4)) {
+ dns4 - &c->ip4.dns[0] < ARRAY_SIZE(c->ip4.dns) - 1
+ && inet_pton(AF_INET, p + 1, &dns4_tmp)) {
/* Guest or container can only access local
* addresses via local redirect
*/
- if (IN4_IS_ADDR_LOOPBACK(dns4)) {
+ if (IN4_IS_ADDR_LOOPBACK(&dns4_tmp)) {
if (!c->no_map_gw) {
- *dns4_send = c->ip4.gw;
- dns4_send++;
+ *dns4 = c->ip4.gw;
+ dns4++;
}
} else {
- *dns4_send = *dns4;
- dns4_send++;
+ *dns4 = dns4_tmp;
+ dns4++;
}
- dns4++;
-
- dns4->s_addr = htonl(INADDR_ANY);
- dns4_send->s_addr = htonl(INADDR_ANY);
+ if (IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns_host))
+ c->ip4.dns_host = dns4_tmp;
}
if (!dns6_set &&
- dns6 - &c->ip6.dns[0] < ARRAY_SIZE(c->ip6.dns) - 1 &&
- inet_pton(AF_INET6, p + 1, dns6)) {
+ dns6 - &c->ip6.dns[0] < ARRAY_SIZE(c->ip6.dns) - 1
+ && inet_pton(AF_INET6, p + 1, &dns6_tmp)) {
/* Guest or container can only access local
* addresses via local redirect
*/
- if (IN6_IS_ADDR_LOOPBACK(dns6)) {
+ if (IN6_IS_ADDR_LOOPBACK(&dns6_tmp)) {
if (!c->no_map_gw) {
- memcpy(dns6_send, &c->ip6.gw,
- sizeof(*dns6_send));
- dns6_send++;
+ memcpy(dns6, &c->ip6.gw,
+ sizeof(*dns6));
+ dns6++;
}
} else {
- memcpy(dns6_send, dns6,
- sizeof(*dns6_send));
- dns6_send++;
+ memcpy(dns6, &dns6_tmp, sizeof(*dns6));
+ dns6++;
}
- dns6++;
-
- memset(dns6, 0, sizeof(*dns6));
- memset(dns6_send, 0, sizeof(*dns6_send));
+ if (IN6_IS_ADDR_UNSPECIFIED(&c->ip6.dns_host))
+ c->ip6.dns_host = dns6_tmp;
}
} else if (!dnss_set && strstr(line, "search ") == line &&
s == c->dns_search) {
@@ -897,12 +890,10 @@ static void conf_print(const struct ctx *c)
inet_ntop(AF_INET, &c->ip4.gw, buf4, sizeof(buf4)));
}
- for (i = 0; !IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns_send[i]);
- i++) {
+ for (i = 0; !IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns[i]); i++) {
if (!i)
info("DNS:");
- inet_ntop(AF_INET, &c->ip4.dns_send[i], buf4,
- sizeof(buf4));
+ inet_ntop(AF_INET, &c->ip4.dns[i], buf4, sizeof(buf4));
info(" %s", buf4);
}
@@ -933,8 +924,7 @@ static void conf_print(const struct ctx *c)
inet_ntop(AF_INET6, &c->ip6.addr_ll, buf6, sizeof(buf6)));
dns6:
- for (i = 0; !IN6_IS_ADDR_UNSPECIFIED(&c->ip6.dns_send[i]);
- i++) {
+ for (i = 0; !IN6_IS_ADDR_UNSPECIFIED(&c->ip6.dns[i]); i++) {
if (!i)
info("DNS:");
inet_ntop(AF_INET6, &c->ip6.dns[i], buf6, sizeof(buf6));
@@ -1230,17 +1220,17 @@ void conf(struct ctx *c, int argc, char **argv)
c->no_dhcp_dns_search = 1;
break;
case 9:
- if (IN6_IS_ADDR_UNSPECIFIED(&c->ip6.dns_fwd) &&
- inet_pton(AF_INET6, optarg, &c->ip6.dns_fwd) &&
- !IN6_IS_ADDR_UNSPECIFIED(&c->ip6.dns_fwd) &&
- !IN6_IS_ADDR_LOOPBACK(&c->ip6.dns_fwd))
+ if (IN6_IS_ADDR_UNSPECIFIED(&c->ip6.dns_match) &&
+ inet_pton(AF_INET6, optarg, &c->ip6.dns_match) &&
+ !IN6_IS_ADDR_UNSPECIFIED(&c->ip6.dns_match) &&
+ !IN6_IS_ADDR_LOOPBACK(&c->ip6.dns_match))
break;
- if (IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns_fwd) &&
- inet_pton(AF_INET, optarg, &c->ip4.dns_fwd) &&
- !IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns_fwd) &&
- !IN4_IS_ADDR_BROADCAST(&c->ip4.dns_fwd) &&
- !IN4_IS_ADDR_LOOPBACK(&c->ip4.dns_fwd))
+ if (IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns_match) &&
+ inet_pton(AF_INET, optarg, &c->ip4.dns_match) &&
+ !IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns_match) &&
+ !IN4_IS_ADDR_BROADCAST(&c->ip4.dns_match) &&
+ !IN4_IS_ADDR_LOOPBACK(&c->ip4.dns_match))
break;
err("Invalid DNS forwarding address: %s", optarg);
diff --git a/dhcp.c b/dhcp.c
index 12da47a..6088886 100644
--- a/dhcp.c
+++ b/dhcp.c
@@ -359,9 +359,8 @@ int dhcp(const struct ctx *c, const struct pool *p)
}
for (i = 0, opts[6].slen = 0;
- !c->no_dhcp_dns &&
!IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns_send[i]);
- i++) {
- ((struct in_addr *)opts[6].s)[i] = c->ip4.dns_send[i];
+ !c->no_dhcp_dns && !IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns[i]); i++)
{
+ ((struct in_addr *)opts[6].s)[i] = c->ip4.dns[i];
opts[6].slen += sizeof(uint32_t);
}
diff --git a/dhcpv6.c b/dhcpv6.c
index 67262e6..e763aed 100644
--- a/dhcpv6.c
+++ b/dhcpv6.c
@@ -379,7 +379,7 @@ static size_t dhcpv6_dns_fill(const struct ctx *c, char *buf, int
offset)
if (c->no_dhcp_dns)
goto search;
- for (i = 0; !IN6_IS_ADDR_UNSPECIFIED(&c->ip6.dns_send[i]); i++) {
+ for (i = 0; !IN6_IS_ADDR_UNSPECIFIED(&c->ip6.dns[i]); i++) {
if (!i) {
srv = (struct opt_dns_servers *)(buf + offset);
offset += sizeof(struct opt_hdr);
@@ -387,8 +387,7 @@ static size_t dhcpv6_dns_fill(const struct ctx *c, char *buf, int
offset)
srv->hdr.l = 0;
}
- memcpy(&srv->addr[i], &c->ip6.dns_send[i],
- sizeof(srv->addr[i]));
+ memcpy(&srv->addr[i], &c->ip6.dns[i], sizeof(srv->addr[i]));
srv->hdr.l += sizeof(srv->addr[i]);
offset += sizeof(srv->addr[i]);
}
diff --git a/ndp.c b/ndp.c
index 6d79477..80e1f19 100644
--- a/ndp.c
+++ b/ndp.c
@@ -121,7 +121,7 @@ int ndp(struct ctx *c, const struct icmp6hdr *ih, const struct
in6_addr *saddr)
if (c->no_dhcp_dns)
goto dns_done;
- for (n = 0; !IN6_IS_ADDR_UNSPECIFIED(&c->ip6.dns_send[n]); n++);
+ for (n = 0; !IN6_IS_ADDR_UNSPECIFIED(&c->ip6.dns[n]); n++);
if (n) {
*p++ = 25; /* RDNSS */
*p++ = 1 + 2 * n; /* length */
@@ -130,8 +130,8 @@ int ndp(struct ctx *c, const struct icmp6hdr *ih, const struct
in6_addr *saddr)
p += 4;
for (i = 0; i < n; i++) {
- memcpy(p, &c->ip6.dns_send[i], 16);
- p += 16; /* address */
+ memcpy(p, &c->ip6.dns[i], 16); /* address */
+ p += 16;
}
for (n = 0; *c->dns_search[n].n; n++)
diff --git a/passt.h b/passt.h
index e93eea8..6649c0a 100644
--- a/passt.h
+++ b/passt.h
@@ -101,9 +101,9 @@ enum passt_modes {
* @addr_seen: Latest IPv4 address seen as source from tap
* @prefixlen: IPv4 prefix length (netmask)
* @gw: Default IPv4 gateway, network order
- * @dns: Host IPv4 DNS addresses, zero-terminated, network order
- * @dns_send: Offered IPv4 DNS, zero-terminated, network order
- * @dns_fwd: Address forwarded (UDP) to first IPv4 DNS, network order
+ * @dns: DNS addresses for DHCP, zero-terminated, network order
+ * @dns_match: Forward DNS query if sent to this address, network order
+ * @dns_host: Use this DNS on the host for forwarding, network order
*/
struct ip4_ctx {
struct in_addr addr;
@@ -111,8 +111,8 @@ struct ip4_ctx {
int prefix_len;
struct in_addr gw;
struct in_addr dns[MAXNS + 1];
- struct in_addr dns_send[MAXNS + 1];
- struct in_addr dns_fwd;
+ struct in_addr dns_match;
+ struct in_addr dns_host;
};
/**
@@ -122,9 +122,9 @@ struct ip4_ctx {
* @addr_seen: Latest IPv6 global/site address seen as source from tap
* @addr_ll_seen: Latest IPv6 link-local address seen as source from tap
* @gw: Default IPv6 gateway
- * @dns: Host IPv6 DNS addresses, zero-terminated
- * @dns_send: Offered IPv6 DNS addresses, zero-terminated
- * @dns_fwd: Address forwarded (UDP) to first IPv6 DNS, network order
+ * @dns: DNS addresses for DHCPv6 and NDP, zero-terminated
+ * @dns_match: Forward DNS query if sent to this address
+ * @dns_host: Use this DNS on the host for forwarding
*/
struct ip6_ctx {
struct in6_addr addr;
@@ -133,8 +133,8 @@ struct ip6_ctx {
struct in6_addr addr_ll_seen;
struct in6_addr gw;
struct in6_addr dns[MAXNS + 1];
- struct in6_addr dns_send[MAXNS + 1];
- struct in6_addr dns_fwd;
+ struct in6_addr dns_match;
+ struct in6_addr dns_host;
};
#include <netinet/if_ether.h>
diff --git a/udp.c b/udp.c
index ff7f993..0aa6308 100644
--- a/udp.c
+++ b/udp.c
@@ -678,10 +678,10 @@ static void udp_sock_fill_data_v4(const struct ctx *c, int n,
src_port = ntohs(b->s_in.sin_port);
- if (!IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns_fwd) &&
- IN4_ARE_ADDR_EQUAL(&b->s_in.sin_addr, &c->ip4.dns[0]) &&
+ 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) {
- b->iph.saddr = c->ip4.dns_fwd.s_addr;
+ 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)) {
@@ -770,10 +770,11 @@ static void udp_sock_fill_data_v6(const struct ctx *c, int n,
if (IN6_IS_ADDR_LINKLOCAL(src)) {
b->ip6h.daddr = c->ip6.addr_ll_seen;
b->ip6h.saddr = b->s_in6.sin6_addr;
- } else if (!IN6_IS_ADDR_UNSPECIFIED(&c->ip6.dns_fwd) &&
- IN6_ARE_ADDR_EQUAL(src, &c->ip6.dns[0]) && src_port == 53) {
+ } else if (!IN6_IS_ADDR_UNSPECIFIED(&c->ip6.dns_match) &&
+ IN6_ARE_ADDR_EQUAL(src, &c->ip6.dns_host) &&
+ src_port == 53) {
b->ip6h.daddr = c->ip6.addr_seen;
- b->ip6h.saddr = c->ip6.dns_fwd;
+ b->ip6h.saddr = c->ip6.dns_match;
} else if (IN6_IS_ADDR_LOOPBACK(src) ||
IN6_ARE_ADDR_EQUAL(src, &c->ip6.addr_seen) ||
IN6_ARE_ADDR_EQUAL(src, &c->ip6.addr)) {
@@ -1016,13 +1017,15 @@ int udp_tap_handler(struct ctx *c, int af, const void *addr,
udp_tap_map[V4][src].ts = now->tv_sec;
- if (IN4_ARE_ADDR_EQUAL(&s_in.sin_addr, &c->ip4.gw) &&
!c->no_map_gw) {
+ if (IN4_ARE_ADDR_EQUAL(&s_in.sin_addr, &c->ip4.gw) &&
+ !c->no_map_gw) {
if (!(udp_tap_map[V4][dst].flags & PORT_LOCAL) ||
(udp_tap_map[V4][dst].flags & PORT_LOOPBACK))
s_in.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
else
s_in.sin_addr = c->ip4.addr_seen;
- } else if (IN4_ARE_ADDR_EQUAL(&s_in.sin_addr, &c->ip4.dns_fwd) &&
+ } else if (IN4_ARE_ADDR_EQUAL(&s_in.sin_addr,
+ &c->ip4.dns_match) &&
ntohs(s_in.sin_port) == 53) {
s_in.sin_addr = c->ip4.dns[0];
}
@@ -1045,7 +1048,7 @@ int udp_tap_handler(struct ctx *c, int af, const void *addr,
s_in6.sin6_addr = c->ip6.addr;
else
s_in6.sin6_addr = c->ip6.addr_seen;
- } else if (IN6_ARE_ADDR_EQUAL(addr, &c->ip6.dns_fwd) &&
+ } else if (IN6_ARE_ADDR_EQUAL(addr, &c->ip6.dns_match) &&
ntohs(s_in6.sin6_port) == 53) {
s_in6.sin6_addr = c->ip6.dns[0];
} else if (IN6_IS_ADDR_LINKLOCAL(&s_in6.sin6_addr)) {
--
2.35.1