From: Stefano Brivio <sbrivio@redhat.com>
To: passt-dev@passt.top
Cc: David Gibson <david@gibson.dropbear.id.au>,
Paul Holzinger <pholzing@redhat.com>
Subject: [PATCH RFT] conf: Introduce default link-local addresses and routes when we can't use any interface as template
Date: Fri, 22 Nov 2024 07:59:12 +0100 [thread overview]
Message-ID: <20241122065912.2248381-1-sbrivio@redhat.com> (raw)
Link: https://github.com/containers/podman/issues/24614
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
---
conf.c | 77 +++++++++++++++++++++++++++++++++++++++++++++++++---------
1 file changed, 66 insertions(+), 11 deletions(-)
diff --git a/conf.c b/conf.c
index 86566db..4c81aaf 100644
--- a/conf.c
+++ b/conf.c
@@ -48,6 +48,23 @@
#define NETNS_RUN_DIR "/run/netns"
+#define IP4_LL_GUEST_ADDR (struct in_addr){ htonl_constant(0xa9fe0a02) }
+ /* 169.254.10.2 */
+
+#define IP4_LL_GUEST_GW (struct in_addr){ htonl_constant(0xa9fe0a01) }
+ /* 169.254.10.1 */
+
+#define IP4_LL_PREFIX_LEN 16
+
+#define IP6_LL_GUEST_ADDR (struct in6_addr) \
+ {{{ 0xfe, 0x80, 0, 0, 0, 0, 0, 0, \
+ 0, 0, 0, 0, 0, 0, 0, 0x02 }}}
+#define IP6_LL_GUEST_GW (struct in6_addr) \
+ {{{ 0xfe, 0x80, 0, 0, 0, 0, 0, 0, \
+ 0, 0, 0, 0, 0, 0, 0, 0x01 }}}
+
+const char *pasta_default_ifn = "tap0";
+
/**
* next_chunk - Return the next piece of a string delimited by a character
* @s: String to search
@@ -631,7 +648,7 @@ static unsigned int conf_ip4(unsigned int ifi, struct ip4_ctx *ip4)
ifi = nl_get_ext_if(nl_sock, AF_INET);
if (!ifi) {
- info("Couldn't pick external interface: disabling IPv4");
+ debug("Failed to detect external interface for IPv4");
return 0;
}
@@ -639,8 +656,8 @@ static unsigned int conf_ip4(unsigned int ifi, struct ip4_ctx *ip4)
int rc = nl_route_get_def(nl_sock, ifi, AF_INET,
&ip4->guest_gw);
if (rc < 0) {
- err("Couldn't discover IPv4 gateway address: %s",
- strerror(-rc));
+ debug("Couldn't discover IPv4 gateway address: %s",
+ strerror(-rc));
return 0;
}
}
@@ -649,8 +666,8 @@ static unsigned int conf_ip4(unsigned int ifi, struct ip4_ctx *ip4)
int rc = nl_addr_get(nl_sock, ifi, AF_INET,
&ip4->addr, &ip4->prefix_len, NULL);
if (rc < 0) {
- err("Couldn't discover IPv4 address: %s",
- strerror(-rc));
+ debug("Couldn't discover IPv4 address: %s",
+ strerror(-rc));
return 0;
}
}
@@ -677,6 +694,19 @@ static unsigned int conf_ip4(unsigned int ifi, struct ip4_ctx *ip4)
return ifi;
}
+/**
+ * conf_ip4_local() - Configure IPv4 link-local addresses for local mode
+ * @ip4: IPv4 context (will be written)
+ */
+static void conf_ip4_local(struct ip4_ctx *ip4)
+{
+ ip4->addr_seen = ip4->addr = IP4_LL_GUEST_ADDR;
+ ip4->our_tap_addr = ip4->guest_gw = IP4_LL_GUEST_GW;
+ ip4->prefix_len = IP4_LL_PREFIX_LEN;
+
+ ip4->no_copy_addrs = ip4->no_copy_routes = true;
+}
+
/**
* conf_ip6() - Verify or detect IPv6 support, get relevant addresses
* @ifi: Host interface to attempt (0 to determine one)
@@ -693,15 +723,15 @@ static unsigned int conf_ip6(unsigned int ifi, struct ip6_ctx *ip6)
ifi = nl_get_ext_if(nl_sock, AF_INET6);
if (!ifi) {
- info("Couldn't pick external interface: disabling IPv6");
+ debug("Failed to detect external interface for IPv6");
return 0;
}
if (IN6_IS_ADDR_UNSPECIFIED(&ip6->guest_gw)) {
rc = nl_route_get_def(nl_sock, ifi, AF_INET6, &ip6->guest_gw);
if (rc < 0) {
- err("Couldn't discover IPv6 gateway address: %s",
- strerror(-rc));
+ debug("Couldn't discover IPv6 gateway address: %s",
+ strerror(-rc));
return 0;
}
}
@@ -710,7 +740,7 @@ static unsigned int conf_ip6(unsigned int ifi, struct ip6_ctx *ip6)
IN6_IS_ADDR_UNSPECIFIED(&ip6->addr) ? &ip6->addr : NULL,
&prefix_len, &ip6->our_tap_ll);
if (rc < 0) {
- err("Couldn't discover IPv6 address: %s", strerror(-rc));
+ debug("Couldn't discover IPv6 address: %s", strerror(-rc));
return 0;
}
@@ -726,6 +756,18 @@ static unsigned int conf_ip6(unsigned int ifi, struct ip6_ctx *ip6)
return ifi;
}
+/**
+ * conf_ip6_local() - Configure IPv6 link-local addresses for local mode
+ * @ip6: IPv6 context (will be written)
+ */
+static void conf_ip6_local(struct ip6_ctx *ip6)
+{
+ ip6->addr_seen = ip6->addr = IP6_LL_GUEST_ADDR;
+ ip6->our_tap_ll = ip6->guest_gw = IP6_LL_GUEST_GW;
+
+ ip6->no_copy_addrs = ip6->no_copy_routes = true;
+}
+
/**
* usage() - Print usage, exit with given status code
* @name: Executable name
@@ -1735,8 +1777,21 @@ void conf(struct ctx *c, int argc, char **argv)
c->ifi6 = conf_ip6(ifi6, &c->ip6);
if ((!c->ifi4 && !c->ifi6) ||
(*c->ip4.ifname_out && !c->ifi4) ||
- (*c->ip6.ifname_out && !c->ifi6))
- die("External interface not usable");
+ (*c->ip6.ifname_out && !c->ifi6)) {
+ /* Switch to local mode */
+ info("No external interface as template, switch to local mode");
+
+ conf_ip4_local(&c->ip4);
+ c->ifi4 = -1;
+
+ conf_ip6_local(&c->ip6);
+ c->ifi6 = -1;
+
+ if (!*c->pasta_ifn) {
+ strncpy(c->pasta_ifn, pasta_default_ifn,
+ sizeof(c->pasta_ifn) - 1);
+ }
+ }
if (c->ifi4 && !no_map_gw &&
IN4_IS_ADDR_UNSPECIFIED(&c->ip4.map_host_loopback))
--
@@ -48,6 +48,23 @@
#define NETNS_RUN_DIR "/run/netns"
+#define IP4_LL_GUEST_ADDR (struct in_addr){ htonl_constant(0xa9fe0a02) }
+ /* 169.254.10.2 */
+
+#define IP4_LL_GUEST_GW (struct in_addr){ htonl_constant(0xa9fe0a01) }
+ /* 169.254.10.1 */
+
+#define IP4_LL_PREFIX_LEN 16
+
+#define IP6_LL_GUEST_ADDR (struct in6_addr) \
+ {{{ 0xfe, 0x80, 0, 0, 0, 0, 0, 0, \
+ 0, 0, 0, 0, 0, 0, 0, 0x02 }}}
+#define IP6_LL_GUEST_GW (struct in6_addr) \
+ {{{ 0xfe, 0x80, 0, 0, 0, 0, 0, 0, \
+ 0, 0, 0, 0, 0, 0, 0, 0x01 }}}
+
+const char *pasta_default_ifn = "tap0";
+
/**
* next_chunk - Return the next piece of a string delimited by a character
* @s: String to search
@@ -631,7 +648,7 @@ static unsigned int conf_ip4(unsigned int ifi, struct ip4_ctx *ip4)
ifi = nl_get_ext_if(nl_sock, AF_INET);
if (!ifi) {
- info("Couldn't pick external interface: disabling IPv4");
+ debug("Failed to detect external interface for IPv4");
return 0;
}
@@ -639,8 +656,8 @@ static unsigned int conf_ip4(unsigned int ifi, struct ip4_ctx *ip4)
int rc = nl_route_get_def(nl_sock, ifi, AF_INET,
&ip4->guest_gw);
if (rc < 0) {
- err("Couldn't discover IPv4 gateway address: %s",
- strerror(-rc));
+ debug("Couldn't discover IPv4 gateway address: %s",
+ strerror(-rc));
return 0;
}
}
@@ -649,8 +666,8 @@ static unsigned int conf_ip4(unsigned int ifi, struct ip4_ctx *ip4)
int rc = nl_addr_get(nl_sock, ifi, AF_INET,
&ip4->addr, &ip4->prefix_len, NULL);
if (rc < 0) {
- err("Couldn't discover IPv4 address: %s",
- strerror(-rc));
+ debug("Couldn't discover IPv4 address: %s",
+ strerror(-rc));
return 0;
}
}
@@ -677,6 +694,19 @@ static unsigned int conf_ip4(unsigned int ifi, struct ip4_ctx *ip4)
return ifi;
}
+/**
+ * conf_ip4_local() - Configure IPv4 link-local addresses for local mode
+ * @ip4: IPv4 context (will be written)
+ */
+static void conf_ip4_local(struct ip4_ctx *ip4)
+{
+ ip4->addr_seen = ip4->addr = IP4_LL_GUEST_ADDR;
+ ip4->our_tap_addr = ip4->guest_gw = IP4_LL_GUEST_GW;
+ ip4->prefix_len = IP4_LL_PREFIX_LEN;
+
+ ip4->no_copy_addrs = ip4->no_copy_routes = true;
+}
+
/**
* conf_ip6() - Verify or detect IPv6 support, get relevant addresses
* @ifi: Host interface to attempt (0 to determine one)
@@ -693,15 +723,15 @@ static unsigned int conf_ip6(unsigned int ifi, struct ip6_ctx *ip6)
ifi = nl_get_ext_if(nl_sock, AF_INET6);
if (!ifi) {
- info("Couldn't pick external interface: disabling IPv6");
+ debug("Failed to detect external interface for IPv6");
return 0;
}
if (IN6_IS_ADDR_UNSPECIFIED(&ip6->guest_gw)) {
rc = nl_route_get_def(nl_sock, ifi, AF_INET6, &ip6->guest_gw);
if (rc < 0) {
- err("Couldn't discover IPv6 gateway address: %s",
- strerror(-rc));
+ debug("Couldn't discover IPv6 gateway address: %s",
+ strerror(-rc));
return 0;
}
}
@@ -710,7 +740,7 @@ static unsigned int conf_ip6(unsigned int ifi, struct ip6_ctx *ip6)
IN6_IS_ADDR_UNSPECIFIED(&ip6->addr) ? &ip6->addr : NULL,
&prefix_len, &ip6->our_tap_ll);
if (rc < 0) {
- err("Couldn't discover IPv6 address: %s", strerror(-rc));
+ debug("Couldn't discover IPv6 address: %s", strerror(-rc));
return 0;
}
@@ -726,6 +756,18 @@ static unsigned int conf_ip6(unsigned int ifi, struct ip6_ctx *ip6)
return ifi;
}
+/**
+ * conf_ip6_local() - Configure IPv6 link-local addresses for local mode
+ * @ip6: IPv6 context (will be written)
+ */
+static void conf_ip6_local(struct ip6_ctx *ip6)
+{
+ ip6->addr_seen = ip6->addr = IP6_LL_GUEST_ADDR;
+ ip6->our_tap_ll = ip6->guest_gw = IP6_LL_GUEST_GW;
+
+ ip6->no_copy_addrs = ip6->no_copy_routes = true;
+}
+
/**
* usage() - Print usage, exit with given status code
* @name: Executable name
@@ -1735,8 +1777,21 @@ void conf(struct ctx *c, int argc, char **argv)
c->ifi6 = conf_ip6(ifi6, &c->ip6);
if ((!c->ifi4 && !c->ifi6) ||
(*c->ip4.ifname_out && !c->ifi4) ||
- (*c->ip6.ifname_out && !c->ifi6))
- die("External interface not usable");
+ (*c->ip6.ifname_out && !c->ifi6)) {
+ /* Switch to local mode */
+ info("No external interface as template, switch to local mode");
+
+ conf_ip4_local(&c->ip4);
+ c->ifi4 = -1;
+
+ conf_ip6_local(&c->ip6);
+ c->ifi6 = -1;
+
+ if (!*c->pasta_ifn) {
+ strncpy(c->pasta_ifn, pasta_default_ifn,
+ sizeof(c->pasta_ifn) - 1);
+ }
+ }
if (c->ifi4 && !no_map_gw &&
IN4_IS_ADDR_UNSPECIFIED(&c->ip4.map_host_loopback))
--
2.43.0
reply other threads:[~2024-11-22 6:59 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20241122065912.2248381-1-sbrivio@redhat.com \
--to=sbrivio@redhat.com \
--cc=david@gibson.dropbear.id.au \
--cc=passt-dev@passt.top \
--cc=pholzing@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://passt.top/passt
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for IMAP folder(s).