* [PATCH 2/3] conf: Delay handling -D option until after addresses are configured
2024-08-12 9:53 [PATCH 0/3] Assorted fixes related to addressing David Gibson
2024-08-12 9:53 ` [PATCH 1/3] Correct inaccurate comments on ip[46]_ctx::addr David Gibson
@ 2024-08-12 9:53 ` David Gibson
2024-08-12 9:53 ` [PATCH 3/3] fwd: Rework inconsistencies in translation of inbound flows David Gibson
2 siblings, 0 replies; 6+ messages in thread
From: David Gibson @ 2024-08-12 9:53 UTC (permalink / raw)
To: passt-dev, Stefano Brivio; +Cc: David Gibson
add_dns[46]() rely on the gateway address and c->no_map_gw being already
initialised, in order to properly handle DNS servers which need NAT to be
accessed from the guest.
Usually these are called from get_dns() which is well after the addresses
are configured, so that's fine. However, they can also be called earlier
if an explicit -D command line option is given. In this case no_map_gw
and/or c->ip[46].gw may not get be initialised properly, leading to this
doing the wrong thing.
Luckily we already have a second pass of option parsing for things which
need addresses to already be configured. Move handling of -D to there.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
conf.c | 84 +++++++++++++++++++++++++++++++---------------------------
1 file changed, 45 insertions(+), 39 deletions(-)
diff --git a/conf.c b/conf.c
index a79e7a66..76d37da0 100644
--- a/conf.c
+++ b/conf.c
@@ -1235,10 +1235,10 @@ void conf(struct ctx *c, int argc, char **argv)
const char *logname = (c->mode == MODE_PASTA) ? "pasta" : "passt";
char userns[PATH_MAX] = { 0 }, netns[PATH_MAX] = { 0 };
bool copy_addrs_opt = false, copy_routes_opt = false;
- struct in6_addr *dns6 = c->ip6.dns, dns6_tmp;
- struct in_addr *dns4 = c->ip4.dns, dns4_tmp;
enum fwd_ports_mode fwd_default = FWD_NONE;
bool v4_only = false, v6_only = false;
+ struct in6_addr *dns6 = c->ip6.dns;
+ struct in_addr *dns4 = c->ip4.dns;
struct fqdn *dnss = c->dns_search;
unsigned int ifi4 = 0, ifi6 = 0;
const char *logfile = NULL;
@@ -1545,40 +1545,6 @@ void conf(struct ctx *c, int argc, char **argv)
die("Invalid or redundant outbound address: %s",
optarg);
break;
- case 'D':
- if (!strcmp(optarg, "none")) {
- c->no_dns = 1;
-
- dns4 = &c->ip4.dns[0];
- memset(c->ip4.dns, 0, sizeof(c->ip4.dns));
- c->ip4.dns[0] = (struct in_addr){ 0 };
- c->ip4.dns_match = (struct in_addr){ 0 };
- c->ip4.dns_host = (struct in_addr){ 0 };
-
- dns6 = &c->ip6.dns[0];
- memset(c->ip6.dns, 0, sizeof(c->ip6.dns));
- c->ip6.dns_match = (struct in6_addr){ 0 };
- c->ip6.dns_host = (struct in6_addr){ 0 };
-
- break;
- }
-
- c->no_dns = 0;
-
- if (dns4 - &c->ip4.dns[0] < ARRAY_SIZE(c->ip4.dns) &&
- inet_pton(AF_INET, optarg, &dns4_tmp)) {
- add_dns4(c, &dns4_tmp, &dns4);
- break;
- }
-
- if (dns6 - &c->ip6.dns[0] < ARRAY_SIZE(c->ip6.dns) &&
- inet_pton(AF_INET6, optarg, &dns6_tmp)) {
- add_dns6(c, &dns6_tmp, &dns6);
- break;
- }
-
- die("Cannot use DNS address %s", optarg);
- break;
case 'S':
if (!strcmp(optarg, "none")) {
c->no_dns_search = 1;
@@ -1620,6 +1586,7 @@ void conf(struct ctx *c, int argc, char **argv)
case 'u':
case 'T':
case 'U':
+ case 'D':
/* Handle these later, once addresses are configured */
break;
case 'h':
@@ -1677,16 +1644,55 @@ void conf(struct ctx *c, int argc, char **argv)
if (c->ifi6 && IN6_IS_ADDR_UNSPECIFIED(&c->ip6.gw))
c->no_map_gw = 1;
- /* Inbound port options can be parsed now (after IPv4/IPv6 settings) */
+ /* Inbound port options & DNS can be parsed now (after IPv4/IPv6
+ * settings)
+ */
udp_portmap_clear();
optind = 1;
do {
name = getopt_long(argc, argv, optstring, options, NULL);
- if (name == 't')
+ if (name == 't') {
conf_ports(c, name, optarg, &c->tcp.fwd_in);
- else if (name == 'u')
+ } else if (name == 'u') {
conf_ports(c, name, optarg, &c->udp.fwd_in);
+ } else if (name == 'D') {
+ struct in6_addr dns6_tmp;
+ struct in_addr dns4_tmp;
+
+ if (!strcmp(optarg, "none")) {
+ c->no_dns = 1;
+
+ dns4 = &c->ip4.dns[0];
+ memset(c->ip4.dns, 0, sizeof(c->ip4.dns));
+ c->ip4.dns[0] = (struct in_addr){ 0 };
+ c->ip4.dns_match = (struct in_addr){ 0 };
+ c->ip4.dns_host = (struct in_addr){ 0 };
+
+ dns6 = &c->ip6.dns[0];
+ memset(c->ip6.dns, 0, sizeof(c->ip6.dns));
+ c->ip6.dns_match = (struct in6_addr){ 0 };
+ c->ip6.dns_host = (struct in6_addr){ 0 };
+
+ continue;
+ }
+
+ c->no_dns = 0;
+
+ if (dns4 - &c->ip4.dns[0] < ARRAY_SIZE(c->ip4.dns) &&
+ inet_pton(AF_INET, optarg, &dns4_tmp)) {
+ add_dns4(c, &dns4_tmp, &dns4);
+ break;
+ }
+
+ if (dns6 - &c->ip6.dns[0] < ARRAY_SIZE(c->ip6.dns) &&
+ inet_pton(AF_INET6, optarg, &dns6_tmp)) {
+ add_dns6(c, &dns6_tmp, &dns6);
+ break;
+ }
+
+ die("Cannot use DNS address %s", optarg);
+ }
} while (name != -1);
if (c->mode == MODE_PASTA)
--
@@ -1235,10 +1235,10 @@ void conf(struct ctx *c, int argc, char **argv)
const char *logname = (c->mode == MODE_PASTA) ? "pasta" : "passt";
char userns[PATH_MAX] = { 0 }, netns[PATH_MAX] = { 0 };
bool copy_addrs_opt = false, copy_routes_opt = false;
- struct in6_addr *dns6 = c->ip6.dns, dns6_tmp;
- struct in_addr *dns4 = c->ip4.dns, dns4_tmp;
enum fwd_ports_mode fwd_default = FWD_NONE;
bool v4_only = false, v6_only = false;
+ struct in6_addr *dns6 = c->ip6.dns;
+ struct in_addr *dns4 = c->ip4.dns;
struct fqdn *dnss = c->dns_search;
unsigned int ifi4 = 0, ifi6 = 0;
const char *logfile = NULL;
@@ -1545,40 +1545,6 @@ void conf(struct ctx *c, int argc, char **argv)
die("Invalid or redundant outbound address: %s",
optarg);
break;
- case 'D':
- if (!strcmp(optarg, "none")) {
- c->no_dns = 1;
-
- dns4 = &c->ip4.dns[0];
- memset(c->ip4.dns, 0, sizeof(c->ip4.dns));
- c->ip4.dns[0] = (struct in_addr){ 0 };
- c->ip4.dns_match = (struct in_addr){ 0 };
- c->ip4.dns_host = (struct in_addr){ 0 };
-
- dns6 = &c->ip6.dns[0];
- memset(c->ip6.dns, 0, sizeof(c->ip6.dns));
- c->ip6.dns_match = (struct in6_addr){ 0 };
- c->ip6.dns_host = (struct in6_addr){ 0 };
-
- break;
- }
-
- c->no_dns = 0;
-
- if (dns4 - &c->ip4.dns[0] < ARRAY_SIZE(c->ip4.dns) &&
- inet_pton(AF_INET, optarg, &dns4_tmp)) {
- add_dns4(c, &dns4_tmp, &dns4);
- break;
- }
-
- if (dns6 - &c->ip6.dns[0] < ARRAY_SIZE(c->ip6.dns) &&
- inet_pton(AF_INET6, optarg, &dns6_tmp)) {
- add_dns6(c, &dns6_tmp, &dns6);
- break;
- }
-
- die("Cannot use DNS address %s", optarg);
- break;
case 'S':
if (!strcmp(optarg, "none")) {
c->no_dns_search = 1;
@@ -1620,6 +1586,7 @@ void conf(struct ctx *c, int argc, char **argv)
case 'u':
case 'T':
case 'U':
+ case 'D':
/* Handle these later, once addresses are configured */
break;
case 'h':
@@ -1677,16 +1644,55 @@ void conf(struct ctx *c, int argc, char **argv)
if (c->ifi6 && IN6_IS_ADDR_UNSPECIFIED(&c->ip6.gw))
c->no_map_gw = 1;
- /* Inbound port options can be parsed now (after IPv4/IPv6 settings) */
+ /* Inbound port options & DNS can be parsed now (after IPv4/IPv6
+ * settings)
+ */
udp_portmap_clear();
optind = 1;
do {
name = getopt_long(argc, argv, optstring, options, NULL);
- if (name == 't')
+ if (name == 't') {
conf_ports(c, name, optarg, &c->tcp.fwd_in);
- else if (name == 'u')
+ } else if (name == 'u') {
conf_ports(c, name, optarg, &c->udp.fwd_in);
+ } else if (name == 'D') {
+ struct in6_addr dns6_tmp;
+ struct in_addr dns4_tmp;
+
+ if (!strcmp(optarg, "none")) {
+ c->no_dns = 1;
+
+ dns4 = &c->ip4.dns[0];
+ memset(c->ip4.dns, 0, sizeof(c->ip4.dns));
+ c->ip4.dns[0] = (struct in_addr){ 0 };
+ c->ip4.dns_match = (struct in_addr){ 0 };
+ c->ip4.dns_host = (struct in_addr){ 0 };
+
+ dns6 = &c->ip6.dns[0];
+ memset(c->ip6.dns, 0, sizeof(c->ip6.dns));
+ c->ip6.dns_match = (struct in6_addr){ 0 };
+ c->ip6.dns_host = (struct in6_addr){ 0 };
+
+ continue;
+ }
+
+ c->no_dns = 0;
+
+ if (dns4 - &c->ip4.dns[0] < ARRAY_SIZE(c->ip4.dns) &&
+ inet_pton(AF_INET, optarg, &dns4_tmp)) {
+ add_dns4(c, &dns4_tmp, &dns4);
+ break;
+ }
+
+ if (dns6 - &c->ip6.dns[0] < ARRAY_SIZE(c->ip6.dns) &&
+ inet_pton(AF_INET6, optarg, &dns6_tmp)) {
+ add_dns6(c, &dns6_tmp, &dns6);
+ break;
+ }
+
+ die("Cannot use DNS address %s", optarg);
+ }
} while (name != -1);
if (c->mode == MODE_PASTA)
--
2.46.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 3/3] fwd: Rework inconsistencies in translation of inbound flows
2024-08-12 9:53 [PATCH 0/3] Assorted fixes related to addressing David Gibson
2024-08-12 9:53 ` [PATCH 1/3] Correct inaccurate comments on ip[46]_ctx::addr David Gibson
2024-08-12 9:53 ` [PATCH 2/3] conf: Delay handling -D option until after addresses are configured David Gibson
@ 2024-08-12 9:53 ` David Gibson
2024-08-12 21:51 ` Stefano Brivio
2 siblings, 1 reply; 6+ messages in thread
From: David Gibson @ 2024-08-12 9:53 UTC (permalink / raw)
To: passt-dev, Stefano Brivio; +Cc: David Gibson
We usually avoid NAT, but in a few cases we need to apply address
translations. The current logic for this on inbound flows has some
inconsistencies:
* For IPv4 (but not IPv6) we translated unspecified source addresses
While an unspecified source probably doesn't make sense, it makes no less
sense in the guest context than it does for the host, it's possible there
could be protocols / flow types where this works. At the moment, this
should never happen since the protocols will drop the flow before getting
here. So, don't alter unspecified addresses for either IP version.
* For IPv6 (but not IPv4) we translated the guest's assigned address
We always translated the guest's observed address, but for the case where
the assigned address different we should be consistent. Translate the
guest assigned address for IPv4 as well.
The overall point is that we need to translate here if and only if the host
address is one that's not accessible to the guest. Create some helper
functions to determine this, which will have additional uses later.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
fwd.c | 88 +++++++++++++++++++++++++++++++++++++++++++++++++++--------
1 file changed, 77 insertions(+), 11 deletions(-)
diff --git a/fwd.c b/fwd.c
index dea36f6c..24700998 100644
--- a/fwd.c
+++ b/fwd.c
@@ -170,6 +170,73 @@ static bool is_dns_flow(uint8_t proto, const struct flowside *ini)
((ini->fport == 53) || (ini->fport == 853));
}
+/**
+ * fwd_guest_accessible4() - Is IPv4 address guest accessible
+ * @c: Execution context
+ * @addr: Host visible IPv4 address
+ *
+ * Return: true if @addr on the host is accessible to the guest without
+ * translation, false otherwise
+ */
+static bool fwd_guest_accessible4(const struct ctx *c,
+ const struct in_addr *addr)
+{
+ if (IN4_IS_ADDR_LOOPBACK(addr))
+ return false;
+
+ if (IN4_ARE_ADDR_EQUAL(addr, &c->ip4.addr))
+ return false;
+
+ if (!IN4_IS_ADDR_UNSPECIFIED(&c->ip4.addr_seen) &&
+ IN4_ARE_ADDR_EQUAL(addr, &c->ip4.addr_seen))
+ return false;
+
+ return true;
+}
+
+/**
+ * fwd_guest_accessible6() - Is IPv6 address guest accessible
+ * @c: Execution context
+ * @addr: Host visible IPv6 address
+ *
+ * Return: true if @addr on the host is accessible to the guest without
+ * translation, false otherwise
+ */
+static bool fwd_guest_accessible6(const struct ctx *c,
+ const struct in6_addr *addr)
+{
+ if (IN6_IS_ADDR_LOOPBACK(addr))
+ return false;
+
+ if (IN6_ARE_ADDR_EQUAL(addr, &c->ip6.addr))
+ return false;
+
+ if (!IN6_IS_ADDR_UNSPECIFIED(&c->ip6.addr_seen) &&
+ IN6_ARE_ADDR_EQUAL(addr, &c->ip6.addr_seen))
+ return false;
+
+ return true;
+}
+
+/**
+ * fwd_guest_accessible() - Is IPv[46] address guest accessible
+ * @c: Execution context
+ * @addr: Host visible IPv[46] address
+ *
+ * Return: true if @addr on the host is accessible to the guest without
+ * translation, false otherwise
+ */
+static bool fwd_guest_accessible(const struct ctx *c,
+ const union inany_addr *addr)
+{
+ const struct in_addr *a4 = inany_v4(addr);
+
+ if (a4)
+ return fwd_guest_accessible4(c, a4);
+
+ return fwd_guest_accessible6(c, &addr->a6);
+}
+
/**
* fwd_nat_from_tap() - Determine to forward a flow from the tap interface
* @c: Execution context
@@ -307,21 +374,20 @@ uint8_t fwd_nat_from_host(const struct ctx *c, uint8_t proto,
return PIF_SPLICE;
}
- tgt->faddr = ini->eaddr;
- tgt->fport = ini->eport;
-
- if (inany_is_loopback4(&tgt->faddr) ||
- inany_is_unspecified4(&tgt->faddr) ||
- inany_equals4(&tgt->faddr, &c->ip4.addr_seen)) {
- tgt->faddr = inany_from_v4(c->ip4.gw);
- } else if (inany_is_loopback6(&tgt->faddr) ||
- inany_equals6(&tgt->faddr, &c->ip6.addr_seen) ||
- inany_equals6(&tgt->faddr, &c->ip6.addr)) {
- if (IN6_IS_ADDR_LINKLOCAL(&c->ip6.gw))
+ /* These host-visible addresses aren't visible to the guest, so need
+ * translation
+ */
+ if (!fwd_guest_accessible(c, &ini->eaddr)) {
+ if (inany_v4(&ini->eaddr))
+ tgt->faddr = inany_from_v4(c->ip4.gw);
+ else if (IN6_IS_ADDR_LINKLOCAL(&c->ip6.gw))
tgt->faddr.a6 = c->ip6.gw;
else
tgt->faddr.a6 = c->ip6.addr_ll;
+ } else {
+ tgt->faddr = ini->eaddr;
}
+ tgt->fport = ini->eport;
if (inany_v4(&tgt->faddr)) {
tgt->eaddr = inany_from_v4(c->ip4.addr_seen);
--
@@ -170,6 +170,73 @@ static bool is_dns_flow(uint8_t proto, const struct flowside *ini)
((ini->fport == 53) || (ini->fport == 853));
}
+/**
+ * fwd_guest_accessible4() - Is IPv4 address guest accessible
+ * @c: Execution context
+ * @addr: Host visible IPv4 address
+ *
+ * Return: true if @addr on the host is accessible to the guest without
+ * translation, false otherwise
+ */
+static bool fwd_guest_accessible4(const struct ctx *c,
+ const struct in_addr *addr)
+{
+ if (IN4_IS_ADDR_LOOPBACK(addr))
+ return false;
+
+ if (IN4_ARE_ADDR_EQUAL(addr, &c->ip4.addr))
+ return false;
+
+ if (!IN4_IS_ADDR_UNSPECIFIED(&c->ip4.addr_seen) &&
+ IN4_ARE_ADDR_EQUAL(addr, &c->ip4.addr_seen))
+ return false;
+
+ return true;
+}
+
+/**
+ * fwd_guest_accessible6() - Is IPv6 address guest accessible
+ * @c: Execution context
+ * @addr: Host visible IPv6 address
+ *
+ * Return: true if @addr on the host is accessible to the guest without
+ * translation, false otherwise
+ */
+static bool fwd_guest_accessible6(const struct ctx *c,
+ const struct in6_addr *addr)
+{
+ if (IN6_IS_ADDR_LOOPBACK(addr))
+ return false;
+
+ if (IN6_ARE_ADDR_EQUAL(addr, &c->ip6.addr))
+ return false;
+
+ if (!IN6_IS_ADDR_UNSPECIFIED(&c->ip6.addr_seen) &&
+ IN6_ARE_ADDR_EQUAL(addr, &c->ip6.addr_seen))
+ return false;
+
+ return true;
+}
+
+/**
+ * fwd_guest_accessible() - Is IPv[46] address guest accessible
+ * @c: Execution context
+ * @addr: Host visible IPv[46] address
+ *
+ * Return: true if @addr on the host is accessible to the guest without
+ * translation, false otherwise
+ */
+static bool fwd_guest_accessible(const struct ctx *c,
+ const union inany_addr *addr)
+{
+ const struct in_addr *a4 = inany_v4(addr);
+
+ if (a4)
+ return fwd_guest_accessible4(c, a4);
+
+ return fwd_guest_accessible6(c, &addr->a6);
+}
+
/**
* fwd_nat_from_tap() - Determine to forward a flow from the tap interface
* @c: Execution context
@@ -307,21 +374,20 @@ uint8_t fwd_nat_from_host(const struct ctx *c, uint8_t proto,
return PIF_SPLICE;
}
- tgt->faddr = ini->eaddr;
- tgt->fport = ini->eport;
-
- if (inany_is_loopback4(&tgt->faddr) ||
- inany_is_unspecified4(&tgt->faddr) ||
- inany_equals4(&tgt->faddr, &c->ip4.addr_seen)) {
- tgt->faddr = inany_from_v4(c->ip4.gw);
- } else if (inany_is_loopback6(&tgt->faddr) ||
- inany_equals6(&tgt->faddr, &c->ip6.addr_seen) ||
- inany_equals6(&tgt->faddr, &c->ip6.addr)) {
- if (IN6_IS_ADDR_LINKLOCAL(&c->ip6.gw))
+ /* These host-visible addresses aren't visible to the guest, so need
+ * translation
+ */
+ if (!fwd_guest_accessible(c, &ini->eaddr)) {
+ if (inany_v4(&ini->eaddr))
+ tgt->faddr = inany_from_v4(c->ip4.gw);
+ else if (IN6_IS_ADDR_LINKLOCAL(&c->ip6.gw))
tgt->faddr.a6 = c->ip6.gw;
else
tgt->faddr.a6 = c->ip6.addr_ll;
+ } else {
+ tgt->faddr = ini->eaddr;
}
+ tgt->fport = ini->eport;
if (inany_v4(&tgt->faddr)) {
tgt->eaddr = inany_from_v4(c->ip4.addr_seen);
--
2.46.0
^ permalink raw reply related [flat|nested] 6+ messages in thread