Merge branch 'icmp-forwarding'

Adds support for ICMP error forwarding that the kernel supports properly since v6.9 (it still sends locally generated errors from the wrong source IP, though).
2026-02-12 16:23:07 +01:00
parent 3df3af8eb7 a7c03a415e
commit 1db0c19dff
35 changed files with 776 additions and 16 deletions
@@ -420,6 +420,9 @@ enum child_cfg_option_t {

 	/** Enable UDP encapsulation for per-CPU CHILD_SAs */
 	OPT_PER_CPU_SAS_ENCAP = (1<<10),
+
+	/** Enable automatic forwarding of certain ICMP errors */
+	OPT_FORWARD_ICMP = (1<<11),
 };

 /**
@@ -115,6 +115,8 @@ struct kernel_ipsec_add_sa_t {
 	dscp_copy_t copy_dscp;
 	/** TRUE if the peer doesn't support receiving fragments in AGGFRAG pkts */
 	bool iptfs_dont_frag;
+	/** Whether to automatically forward certain ICMP error messages */
+	bool forward_icmp;
 	/** TRUE if initiator of the exchange creating the SA */
 	bool initiator;
 	/** TRUE if this is an inbound SA */
@@ -190,6 +192,8 @@ struct kernel_ipsec_manage_policy_t {
 	hw_offload_t hw_offload;
 	/** Enable per-CPU acquires */
 	bool pcpu_acquires;
+	/** Whether to automatically forward certain ICMP error messages */
+	bool forward_icmp;
 	/** Source address of the SA(s) tied to this policy */
 	host_t *src;
 	/** Destination address of the SA(s) tied to this policy */
@@ -470,7 +470,7 @@ static u_int ipsec_sa_hash(ipsec_sa_t *sa)
 						  chunk_hash_inc(chunk_from_thing(sa->mark),
 						  chunk_hash_inc(chunk_from_thing(sa->if_id),
 						  chunk_hash_inc(chunk_from_thing(sa->hw_offload),
-						  chunk_hash(chunk_from_thing(sa->cfg)))))));
+						  ipsec_sa_cfg_hash(&sa->cfg))))));
 }

 /**
@@ -554,6 +554,9 @@ struct policy_sa_t {
 	/** Whether to trigger per-CPU acquires for this policy */
 	bool pcpu_acquires;

+	/** Whether to forward certain ICMP error messages for this policy */
+	bool forward_icmp;
+
 	/** Assigned SA */
 	ipsec_sa_t *sa;
 };
@@ -577,19 +580,16 @@ struct policy_sa_out_t {
 * Create a policy_sa(_out)_t object
 */
 static policy_sa_t *policy_sa_create(private_kernel_netlink_ipsec_t *this,
-	policy_dir_t dir, policy_type_t type, host_t *src, host_t *dst,
-	traffic_selector_t *src_ts, traffic_selector_t *dst_ts, mark_t mark,
-	uint32_t if_id, hw_offload_t hw_offload, bool pcpu_acquires,
-	ipsec_sa_cfg_t *cfg)
+	kernel_ipsec_policy_id_t *id, kernel_ipsec_manage_policy_t *data)
 {
 	policy_sa_t *policy;

-	if (dir == POLICY_OUT)
+	if (id->dir == POLICY_OUT)
 	{
 		policy_sa_out_t *out;
 		INIT(out,
-			.src_ts = src_ts->clone(src_ts),
-			.dst_ts = dst_ts->clone(dst_ts),
+			.src_ts = id->src_ts->clone(id->src_ts),
+			.dst_ts = id->dst_ts->clone(id->dst_ts),
 		);
 		policy = &out->generic;
 	}
@@ -597,9 +597,11 @@ static policy_sa_t *policy_sa_create(private_kernel_netlink_ipsec_t *this,
 	{
 		INIT(policy, .priority = 0);
 	}
-	policy->type = type;
-	policy->pcpu_acquires = pcpu_acquires;
-	policy->sa = ipsec_sa_create(this, src, dst, mark, if_id, hw_offload, cfg);
+	policy->type = data->type;
+	policy->pcpu_acquires = data->pcpu_acquires;
+	policy->forward_icmp = data->forward_icmp;
+	policy->sa = ipsec_sa_create(this, data->src, data->dst, id->mark,
+								 id->if_id, data->hw_offload, data->sa);
 	return policy;
 }

@@ -1807,6 +1809,11 @@ METHOD(kernel_ipsec_t, add_sa, status_t,
 		sa->flags |= XFRM_STATE_NOECN;
 	}

+	if (data->inbound && data->forward_icmp)
+	{
+		sa->flags |= XFRM_STATE_ICMP;
+	}
+
 	if (data->inbound)
 	{
 		switch (data->copy_dscp)
@@ -3065,6 +3072,12 @@ static status_t add_policy_internal(private_kernel_netlink_ipsec_t *this,
 													   : XFRM_POLICY_BLOCK;
 	policy_info->share = XFRM_SHARE_ANY;

+	if (mapping->type == POLICY_IPSEC && policy->direction != POLICY_IN &&
+		mapping->forward_icmp)
+	{
+		policy_info->flags |= XFRM_POLICY_ICMP;
+	}
+
 	/* policies don't expire */
 	policy_info->lft.soft_byte_limit = XFRM_INF;
 	policy_info->lft.soft_packet_limit = XFRM_INF;
@@ -3262,10 +3275,7 @@ METHOD(kernel_ipsec_t, add_policy, status_t,
 	}

 	/* cache the assigned IPsec SA */
-	assigned_sa = policy_sa_create(this, id->dir, data->type, data->src,
-								   data->dst, id->src_ts, id->dst_ts, id->mark,
-								   id->if_id, data->hw_offload,
-								   data->pcpu_acquires, data->sa);
+	assigned_sa = policy_sa_create(this, id, data);
 	assigned_sa->auto_priority = get_priority(policy, data->prio, id->interface);
 	assigned_sa->priority = this->get_priority ? this->get_priority(id, data)
 											   : data->manual_prio;
@@ -3499,6 +3509,7 @@ METHOD(kernel_ipsec_t, del_policy, status_t,
 			auto_priority == mapping->auto_priority &&
 			data->type == mapping->type &&
 			data->pcpu_acquires == mapping->pcpu_acquires &&
+			data->forward_icmp == mapping->forward_icmp &&
 			ipsec_sa_equals(mapping->sa, &assigned_sa))
 		{
 			current->used_by->remove_at(current->used_by, enumerator);
@@ -348,7 +348,7 @@ static u_int ipsec_sa_hash(ipsec_sa_t *sa)
 {
 	return chunk_hash_inc(sa->src->get_address(sa->src),
 						  chunk_hash_inc(sa->dst->get_address(sa->dst),
-						  chunk_hash(chunk_from_thing(sa->cfg))));
+						  ipsec_sa_cfg_hash(&sa->cfg)));
 }

 /**
@@ -591,6 +591,7 @@ static void log_child_data(child_data_t *data, char *name)
 	DBG2(DBG_CFG, "   copy_df = %u", !has_opt(cfg, OPT_NO_COPY_DF));
 	DBG2(DBG_CFG, "   copy_ecn = %u", !has_opt(cfg, OPT_NO_COPY_ECN));
 	DBG2(DBG_CFG, "   copy_dscp = %N", dscp_copy_names, cfg->copy_dscp);
+	DBG2(DBG_CFG, "   icmp = %u", has_opt(cfg, OPT_FORWARD_ICMP));
 }

 /**
@@ -1105,6 +1106,15 @@ CALLBACK(parse_copy_dscp, bool,
 	return FALSE;
 }

+/**
+ * Parse OTP_FORWARD_ICMP option
+ */
+CALLBACK(parse_opt_icmp, bool,
+	child_cfg_option_t *out, chunk_t v)
+{
+	return parse_option(out, OPT_FORWARD_ICMP, v, TRUE);
+}
+
 /**
 * Parse an action_t
 */
@@ -1953,6 +1963,7 @@ CALLBACK(child_kv, bool,
 		{ "copy_df",			parse_opt_copy_df,	&child->cfg.options					},
 		{ "copy_ecn",			parse_opt_copy_ecn,	&child->cfg.options					},
 		{ "copy_dscp",			parse_copy_dscp,	&child->cfg.copy_dscp				},
+		{ "icmp",				parse_opt_icmp,		&child->cfg.options					},
 		{ "if_id_in",			parse_if_id,		&child->cfg.if_id_in				},
 		{ "if_id_out",			parse_if_id,		&child->cfg.if_id_out				},
 		{ "label",				parse_label,		&child->cfg.label					},
@@ -1121,6 +1121,7 @@ static status_t install_internal(private_child_sa_t *this, chunk_t encr,
 		.copy_ecn = !this->config->has_option(this->config, OPT_NO_COPY_ECN),
 		.copy_dscp = this->config->get_copy_dscp(this->config),
 		.iptfs_dont_frag = this->iptfs_dont_frag,
+		.forward_icmp = this->config->has_option(this->config, OPT_FORWARD_ICMP),
 		.label = label_for(this, LABEL_USE_SA),
 		.initiator = initiator,
 		.inbound = inbound,
@@ -1295,6 +1296,7 @@ static status_t install_policies_outbound(private_child_sa_t *this,
 		.src = my_addr,
 		.dst = other_addr,
 		.pcpu_acquires = this->per_cpu,
+		.forward_icmp = this->config->has_option(this->config, OPT_FORWARD_ICMP),
 		.sa = other_sa,
 	};
 	uint32_t reqid = other_sa->reqid;
@@ -1409,6 +1411,7 @@ static void del_policies_outbound(private_child_sa_t *this,
 		.src = my_addr,
 		.dst = other_addr,
 		.pcpu_acquires = this->per_cpu,
+		.forward_icmp = this->config->has_option(this->config, OPT_FORWARD_ICMP),
 		.sa = other_sa,
 	};
 	uint32_t reqid = other_sa->reqid;
@@ -53,6 +53,22 @@ ENUM(dscp_copy_names, DSCP_COPY_OUT_ONLY, DSCP_COPY_NO,
 	"no",
 );

+/*
+ * See header
+ */
+u_int ipsec_sa_cfg_hash(ipsec_sa_cfg_t *this)
+{
+	return chunk_hash_inc(chunk_from_thing(this->mode),
+			chunk_hash_inc(chunk_from_thing(this->reqid),
+			chunk_hash_inc(chunk_from_thing(this->policy_count),
+			chunk_hash_inc(chunk_from_thing(this->esp.use),
+			chunk_hash_inc(chunk_from_thing(this->esp.spi),
+			chunk_hash_inc(chunk_from_thing(this->ah.use),
+			chunk_hash_inc(chunk_from_thing(this->ah.spi),
+			chunk_hash_inc(chunk_from_thing(this->ipcomp.transform),
+				chunk_hash(chunk_from_thing(this->ipcomp.cpi))))))))));
+}
+
 /*
 * See header
 */
@@ -179,6 +179,14 @@ struct ipsec_sa_cfg_t {
 	} ipcomp;
 };

+/**
+ * Hash an ipsec_sa_cfg_t object.
+ *
+ * @param this		object to hash
+ * @return			hash value
+ */
+u_int ipsec_sa_cfg_hash(ipsec_sa_cfg_t *this);
+
 /**
 * Compare two ipsec_sa_cfg_t objects for equality.
 *
@@ -1182,6 +1182,18 @@ connections.<conn>.children.<child>.copy_dscp = out
 	receiver, which is why the default is _out_. Controlling this behavior is
 	not supported by all kernel interfaces.

+connections.<conn>.children.<child>.icmp = no
+	Whether to forward certain ICMP error messages even if their source IP
+	doesn't match the negotiated IPsec policies.
+
+	ICMP error messages, such as Destination Unreachable, Time Exceeded or
+	Fragmentation Needed, may be generated by a host whose IP address isn't
+	included in the negotiated traffic selectors and therefore doesn't match the
+	IPsec policies. If this option is enabled and the kernel supports it, such
+	packets may still be forwarded. As ICMP errors contain parts of the IP
+	packet that triggered them, the kernel will base its decision on a reverse
+	policy lookup using that IP header.
+
 connections.<conn>.children.<child>.start_action = none
 	Action to perform after loading the configuration (_none_, _trap_, _start_).

@@ -0,0 +1,18 @@
+A connection between the gateways <b>moon</b> and <b>sun</b> is set up, which
+connects <b>alice</b> and <b>moon</b> with a small subnet behind gateway <b>sun</b>.
+A second tunnel is created between client <b>venus</b> and gateway <b>moon</b>,
+which connects <b>venus</b> with another small subnet behind, in this case,
+non-IPsec gateway <b>sun</b>.
+The authentication is based on <b>X.509 certificates</b>.
+<p/>
+In order to test ICMP error forwarding, which <b>venus</b>, <b>moon</b> and
+<b>sun</b> all enabled, <b>alice</b> and <b>moon</b> ping unreachable IPs behind
+IPsec gateway <b>sun</b> and behind host <b>bob</b>, respectively. The
+corresponding ICMP Destination Unreachable messages, with source IP addresses
+outside the IPsec tunnel traffic selectors are expected to be forwarded
+by <b>sun</b> and <b>moon</b>.
+<p/>
+Similar tests are run from <b>venus</b>, in which case the non-IPsec router
+<b>sun</b> generates ICMP Time Exceeded (TTL expired) and Fragmentation Needed
+(MTU exceeded) messages with a source IP outside of the traffic selectors.
+These messages should again get forwarded by <b>moon</b>.
@@ -0,0 +1,18 @@
+moon::swanctl --list-sas --raw 2> /dev/null::gw-gw.*version=2 state=ESTABLISHED local-host=192.168.0.1 local-port=500 local-id=moon.strongswan.org remote-host=192.168.0.2 remote-port=500 remote-id=sun.strongswan.org initiator=yes.*encr-alg=AES_CBC encr-keysize=128 integ-alg=HMAC_SHA2_256_128 prf-alg=PRF_HMAC_SHA2_256 dh-group=CURVE_25519.*child-sas.*net-net.*state=INSTALLED mode=TUNNEL.*ESP.*encr-alg=AES_GCM_16 encr-keysize=128.*local-ts=\[10.1.0.0/16] remote-ts=\[10.2.0.16/28]::YES
+sun:: swanctl --list-sas --raw 2> /dev/null::gw-gw.*version=2 state=ESTABLISHED local-host=192.168.0.2 local-port=500 local-id=sun.strongswan.org remote-host=192.168.0.1 remote-port=500 remote-id=moon.strongswan.org.*encr-alg=AES_CBC encr-keysize=128 integ-alg=HMAC_SHA2_256_128 prf-alg=PRF_HMAC_SHA2_256 dh-group=CURVE_25519.*child-sas.*net-net.*state=INSTALLED mode=TUNNEL.*ESP.*encr-alg=AES_GCM_16 encr-keysize=128.*local-ts=\[10.2.0.16/28] remote-ts=\[10.1.0.0/16]::YES
+moon::swanctl --list-sas --raw 2> /dev/null::venus.*version=2 state=ESTABLISHED local-host=10.1.0.1 local-port=500 local-id=moon.strongswan.org remote-host=10.1.0.20 remote-port=500 remote-id=venus.strongswan.org.*encr-alg=AES_CBC encr-keysize=128 integ-alg=HMAC_SHA2_256_128 prf-alg=PRF_HMAC_SHA2_256 dh-group=CURVE_25519.*child-sas.*net-net.*state=INSTALLED mode=TUNNEL.*ESP.*encr-alg=AES_GCM_16 encr-keysize=128.*local-ts=\[10.2.0.8/30] remote-ts=\[10.1.0.20/32]::YES
+venus::swanctl --list-sas --raw 2> /dev/null::rw.*version=2 state=ESTABLISHED local-host=10.1.0.20 local-port=500 local-id=venus.strongswan.org remote-host=10.1.0.1 remote-port=500 remote-id=moon.strongswan.org initiator=yes.*encr-alg=AES_CBC encr-keysize=128 integ-alg=HMAC_SHA2_256_128 prf-alg=PRF_HMAC_SHA2_256 dh-group=CURVE_25519.*child-sas.*rw.*state=INSTALLED mode=TUNNEL.*ESP.*encr-alg=AES_GCM_16 encr-keysize=128.*local-ts=\[10.1.0.20/32] remote-ts=\[10.2.0.8/30]::YES
+# the kernel currently sets the source incorrectly to the non-existent IP
+# allow both in case it gets fixed
+alice::ping -c 1 -W 4 10.2.0.25::From \(PH_IP_SUN\|10.2.0.25\) icmp_seq=1 Destination Host Unreachable::YES
+moon::ping -c 1 -W 4 10.2.0.17::From PH_IP_BOB icmp_seq=1 Destination Host Unreachable::YES
+# test other types of ICMPs with venus
+venus::ping -c 1 PH_IP_BOB::64 bytes from PH_IP_BOB: icmp_.eq=1::YES
+venus::ping -t 2 -c 1 PH_IP_BOB::From PH_IP_SUN.*Time to live exceeded::YES
+venus::ping -M do -s 1320 -c 1 PH_IP_BOB::From PH_IP_SUN.*Frag needed and DF set (mtu = 1280)::YES
+sun::tcpdump::IP moon.strongswan.org > sun.strongswan.org: ESP::2
+sun::tcpdump::IP sun.strongswan.org > moon.strongswan.org: ESP::2
+sun::tcpdump::IP sun.strongswan.org > alice.strongswan.org: ICMP host 10.2.0.25 unreachable::NO
+sun::tcpdump::IP bob.strongswan.org > moon1.strongswan.org: ICMP host 10.2.0.17 unreachable::NO
+venus::tcpdump::IP venus.strongswan.org > moon1.strongswan.org: ESP::3
+venus::tcpdump::IP moon1.strongswan.org > venus.strongswan.org: ESP::3
@@ -0,0 +1,48 @@
+*filter
+
+# default policy is DROP
+-P INPUT DROP
+-P OUTPUT DROP
+-P FORWARD DROP
+
+# allow esp
+-A INPUT  -i eth0 -p 50 -j ACCEPT
+-A OUTPUT -o eth0 -p 50 -j ACCEPT
+
+# allow IKE
+-A INPUT  -i eth0 -p udp --sport 500 --dport 500 -j ACCEPT
+-A OUTPUT -o eth0 -p udp --dport 500 --sport 500 -j ACCEPT
+
+# allow MobIKE
+-A INPUT  -i eth0 -p udp --sport 4500 --dport 4500 -j ACCEPT
+-A OUTPUT -o eth0 -p udp --dport 4500 --sport 4500 -j ACCEPT
+
+# allow ssh
+-A INPUT  -p tcp --dport 22 -j ACCEPT
+-A OUTPUT -p tcp --sport 22 -j ACCEPT
+
+# allow crl fetch from winnetou
+-A INPUT  -i eth0 -p tcp --sport 80 -s 192.168.0.150 -j ACCEPT
+-A OUTPUT -o eth0 -p tcp --dport 80 -d 192.168.0.150 -j ACCEPT
+
+# allow decrypted ICMPs from any source IP (updown script is too specific)
+-A INPUT -p icmp --icmp-type destination-unreachable -m policy --dir in -j ACCEPT
+-A FORWARD -p icmp --icmp-type destination-unreachable -m policy --dir in -j ACCEPT
+
+# allow venus to connect and fetch crls
+-A INPUT -i eth1 -p udp --sport 500 --dport 500 -j ACCEPT
+-A OUTPUT -o eth1 -p udp --dport 500 --sport 500 -j ACCEPT
+-A INPUT -i eth1 -p 50 -j ACCEPT
+-A OUTPUT -o eth1 -p 50 -j ACCEPT
+-A FORWARD -i eth0 -o eth1 -p tcp --sport 80 -s 192.168.0.150 -j ACCEPT
+-A FORWARD -o eth0 -i eth1 -p tcp --dport 80 -d 192.168.0.150 -j ACCEPT
+
+# forward specific errors to venus
+-A FORWARD -d 10.1.0.20/32 -p icmp --icmp-type time-exceeded -j ACCEPT
+-A FORWARD -d 10.1.0.20/32 -p icmp --icmp-type fragmentation-needed -j ACCEPT
+
+# log dropped packets
+-A INPUT  -j LOG --log-prefix " IN: "
+-A OUTPUT -j LOG --log-prefix " OUT: "
+
+COMMIT
@@ -0,0 +1,9 @@
+# /etc/strongswan.conf - strongSwan configuration file
+
+swanctl {
+  load = pem pkcs1 pubkey openssl random
+}
+
+charon-systemd {
+  load = random nonce openssl pem pkcs1 revocation curl kernel-netlink socket-default updown vici
+}
@@ -0,0 +1,48 @@
+connections {
+
+   gw-gw {
+      local_addrs  = PH_IP_MOON
+      remote_addrs = PH_IP_SUN
+
+      local {
+         auth = pubkey
+         certs = moonCert.pem
+         id = moon.strongswan.org
+      }
+      remote {
+         auth = pubkey
+         id = sun.strongswan.org
+      }
+      children {
+         net-net {
+            local_ts  = 10.1.0.0/16
+            remote_ts = 10.2.0.0/16
+            icmp = yes
+
+            updown = /usr/local/libexec/ipsec/_updown iptables
+            hostaccess = yes
+            esp_proposals = aes128gcm128-x25519
+         }
+      }
+      version = 2
+      mobike = no
+      proposals = aes128-sha256-x25519
+   }
+
+   venus : connections.gw-gw {
+      local_addrs = PH_IP_MOON1
+      remote_addrs = PH_IP_VENUS
+
+      remote {
+         id = venus.strongswan.org
+      }
+      children {
+         net-net {
+            # only include bob
+            local_ts = 10.2.0.8/30
+            remote_ts = dynamic
+            hostaccess = no
+         }
+      }
+   }
+}
@@ -0,0 +1,42 @@
+*filter
+
+# default policy is DROP
+-P INPUT DROP
+-P OUTPUT DROP
+-P FORWARD DROP
+
+# allow esp
+-A INPUT  -i eth0 -p 50 -j ACCEPT
+-A OUTPUT -o eth0 -p 50 -j ACCEPT
+
+# allow IKE
+-A INPUT  -i eth0 -p udp --sport 500 --dport 500 -j ACCEPT
+-A OUTPUT -o eth0 -p udp --dport 500 --sport 500 -j ACCEPT
+
+# allow MobIKE
+-A INPUT  -i eth0 -p udp --sport 4500 --dport 4500 -j ACCEPT
+-A OUTPUT -o eth0 -p udp --dport 4500 --sport 4500 -j ACCEPT
+
+# allow ssh
+-A INPUT  -p tcp --dport 22 -j ACCEPT
+-A OUTPUT -p tcp --sport 22 -j ACCEPT
+
+# allow crl fetch from winnetou
+-A INPUT  -i eth0 -p tcp --sport 80 -s 192.168.0.150 -j ACCEPT
+-A OUTPUT -o eth0 -p tcp --dport 80 -d 192.168.0.150 -j ACCEPT
+
+# explicitly allow ICMP responses we don't actually want to see as they should get encrypted
+-A OUTPUT -p icmp --icmp-type destination-unreachable -j ACCEPT
+-A FORWARD -p icmp --icmp-type destination-unreachable -j ACCEPT
+
+# allow only specific ICMPs from/to venus for this scenario
+-A FORWARD -s 10.1.0.20/32 -p icmp --icmp-type echo-request -j ACCEPT
+-A FORWARD -d 10.1.0.20/32 -p icmp --icmp-type echo-reply -j ACCEPT
+-A OUTPUT -d 10.1.0.20/32 -p icmp --icmp-type time-exceeded -j ACCEPT
+-A OUTPUT -d 10.1.0.20/32 -p icmp --icmp-type fragmentation-needed -j ACCEPT
+
+# log dropped packets
+-A INPUT  -j LOG --log-prefix " IN: "
+-A OUTPUT -j LOG --log-prefix " OUT: "
+
+COMMIT
@@ -0,0 +1,9 @@
+# /etc/strongswan.conf - strongSwan configuration file
+
+swanctl {
+  load = pem pkcs1 pubkey openssl random
+}
+
+charon-systemd {
+  load = random nonce openssl pem pkcs1 revocation curl kernel-netlink socket-default updown vici
+}
@@ -0,0 +1,31 @@
+connections {
+
+   gw-gw {
+      local_addrs  = PH_IP_SUN
+      remote_addrs = PH_IP_MOON
+
+      local {
+         auth = pubkey
+         certs = sunCert.pem
+         id = sun.strongswan.org
+      }
+      remote {
+         auth = pubkey
+         id = moon.strongswan.org
+      }
+      children {
+         net-net {
+            # exclude sun's and bob's IPs
+            local_ts  = 10.2.0.16/28
+            remote_ts = 10.1.0.0/16
+            icmp = yes
+
+            updown = /usr/local/libexec/ipsec/_updown iptables
+            esp_proposals = aes128gcm128-x25519
+         }
+      }
+      version = 2
+      mobike = no
+      proposals = aes128-sha256-x25519
+   }
+}
@@ -0,0 +1,9 @@
+# /etc/strongswan.conf - strongSwan configuration file
+
+swanctl {
+  load = pem pkcs1 pubkey openssl random
+}
+
+charon-systemd {
+  load = random nonce openssl pem pkcs1 revocation curl kernel-netlink socket-default updown vici
+}
@@ -0,0 +1,29 @@
+connections {
+
+   rw {
+      remote_addrs = PH_IP_MOON1
+
+      local {
+         auth = pubkey
+         certs = venusCert.pem
+         id = venus.strongswan.org
+      }
+      remote {
+         auth = pubkey
+         id = moon.strongswan.org
+      }
+      children {
+         rw {
+            remote_ts = 10.2.0.0/16
+            icmp = yes
+
+            updown = /usr/local/libexec/ipsec/_updown iptables
+            hostaccess = yes
+            esp_proposals = aes128gcm128-x25519
+         }
+      }
+      version = 2
+      mobike = no
+      proposals = aes128-sha256-x25519
+   }
+}
@@ -0,0 +1,13 @@
+moon::swanctl --terminate --ike gw-gw 2> /dev/null
+moon::swanctl --terminate --ike venus 2> /dev/null
+venus::systemctl stop strongswan
+moon::systemctl stop strongswan
+sun::systemctl stop strongswan
+venus::iptables-restore < /etc/iptables.flush
+moon::iptables-restore < /etc/iptables.flush
+sun::iptables-restore < /etc/iptables.flush
+sun::ip route del 10.2.0.16/30 via PH_IP_BOB
+moon::ip route del 10.2.0.8/30 via PH_IP_SUN
+sun::ip route del PH_IP_VENUS/32 via PH_IP_MOON
+sun::ip route del 10.2.0.8/30 dev eth1 src PH_IP_SUN1
+winnetou::ip route del 10.1.0.0/16 via PH_IP_MOON
@@ -0,0 +1,21 @@
+venus::iptables-restore < /etc/iptables.rules
+moon::iptables-restore < /etc/iptables.rules
+sun::iptables-restore < /etc/iptables.rules
+venus::systemctl start --no-block strongswan
+moon::systemctl start --no-block strongswan
+sun::systemctl start --no-block strongswan
+# add a route for part of the private subnet via bob
+sun::ip route add 10.2.0.16/30 via PH_IP_BOB
+# setup routes to test with venus
+winnetou::ip route add 10.1.0.0/16 via PH_IP_MOON
+moon::ip route add 10.2.0.8/30 via PH_IP_SUN
+sun::ip route add PH_IP_VENUS/32 via PH_IP_MOON
+# force a lower MTU for traffic to bob
+sun::ip route add 10.2.0.8/30 dev eth1 src PH_IP_SUN1 mtu 1280
+# allow decrypted ICMPs from any source IP (rules for sun and moon are in iptables.rules)
+venus::iptables -A INPUT -p icmp -m policy --dir in -j ACCEPT
+venus::expect-connection rw
+moon::expect-connection gw-gw
+sun::expect-connection gw-gw
+moon::swanctl --initiate --child net-net 2> /dev/null
+venus::swanctl --initiate --child rw 2> /dev/null
@@ -0,0 +1,25 @@
+#!/bin/bash
+#
+# This configuration file provides information on the
+# guest instances used for this test
+
+# All guest instances that are required for this test
+#
+VIRTHOSTS="alice venus moon winnetou sun bob"
+
+# Corresponding block diagram
+#
+DIAGRAM="a-v-m-w-s-b.png"
+
+# Guest instances on which tcpdump is to be started
+#
+TCPDUMPHOSTS="venus sun"
+
+# Guest instances on which IPsec is started
+# Used for IPsec logging purposes
+#
+IPSECHOSTS="venus moon sun"
+
+# charon controlled by swanctl
+#
+SWANCTL=1
@@ -0,0 +1,18 @@
+A connection between the gateways <b>moon</b> and <b>sun</b> is set up, which
+connects <b>alice</b> and <b>moon</b> with a small subnet behind gateway <b>sun</b>.
+A second tunnel is created between client <b>venus</b> and gateway <b>moon</b>,
+which connects <b>venus</b> with another small subnet behind, in this case,
+non-IPsec gateway <b>sun</b>.
+The authentication is based on <b>X.509 certificates</b>.
+<p/>
+In order to test ICMPv6 error forwarding, which <b>venus</b>, <b>moon</b> and
+<b>sun</b> all enabled, <b>alice</b> and <b>moon</b> ping unreachable IPs behind
+IPsec gateway <b>sun</b> and behind host <b>bob</b>, respectively. The
+corresponding ICMPv6 Destination Unreachable messages, with source IP addresses
+outside the IPsec tunnel traffic selectors are expected to be forwarded
+by <b>sun</b> and <b>moon</b>.
+<p/>
+Similar tests are run from <b>venus</b>, in which case the non-IPsec router
+<b>sun</b> generates ICMPv6 Time Exceeded (TTL expired) and Packet too big
+(MTU exceeded) messages with a source IP outside of the traffic selectors.
+These messages should again get forwarded by <b>moon</b>.
@@ -0,0 +1,16 @@
+moon::swanctl --list-sas --raw 2> /dev/null::net-net.*version=2 state=ESTABLISHED local-host=fec0:\:1 local-port=500 local-id=moon.strongswan.org remote-host=fec0:\:2 remote-port=500 remote-id=sun.strongswan.org initiator=yes.*encr-alg=AES_CBC encr-keysize=128 integ-alg=HMAC_SHA2_256_128 prf-alg=PRF_HMAC_SHA2_256 dh-group=CURVE_25519.*child-sas.*net-net.*reqid=1 state=INSTALLED mode=TUNNEL protocol=ESP.*encr-alg=AES_CBC encr-keysize=128 integ-alg=HMAC_SHA2_256_128.*local-ts=\[fec1:\:/16] remote-ts=\[fec2:\:20/124]::YES
+sun ::swanctl --list-sas --raw 2> /dev/null::net-net.*version=2 state=ESTABLISHED local-host=fec0:\:2 local-port=500 local-id=sun.strongswan.org remote-host=fec0:\:1 remote-port=500 remote-id=moon.strongswan.org.*encr-alg=AES_CBC encr-keysize=128 integ-alg=HMAC_SHA2_256_128 prf-alg=PRF_HMAC_SHA2_256 dh-group=CURVE_25519.*child-sas.*net-net.*reqid=1 state=INSTALLED mode=TUNNEL protocol=ESP.*encr-alg=AES_CBC encr-keysize=128 integ-alg=HMAC_SHA2_256_128.*local-ts=\[fec2:\:20/124] remote-ts=\[fec1:\:/16]::YES
+moon::swanctl --list-sas --raw 2> /dev/null::venus.*version=2 state=ESTABLISHED local-host=fec1:\:1 local-port=500 local-id=moon.strongswan.org remote-host=fec1:\:20 remote-port=500 remote-id=venus.strongswan.org.*encr-alg=AES_CBC encr-keysize=128 integ-alg=HMAC_SHA2_256_128 prf-alg=PRF_HMAC_SHA2_256 dh-group=CURVE_25519.*child-sas.*net-net.*reqid=2 state=INSTALLED mode=TUNNEL protocol=ESP.*encr-alg=AES_CBC encr-keysize=128 integ-alg=HMAC_SHA2_256_128.*local-ts=\[fec2:\:10/124] remote-ts=\[fec1:\:20/128]::YES
+venus::swanctl --list-sas --raw 2> /dev/null::rw.*version=2 state=ESTABLISHED local-host=fec1:\:20 local-port=500 local-id=venus.strongswan.org remote-host=fec1:\:1 remote-port=500 remote-id=moon.strongswan.org initiator=yes.*encr-alg=AES_CBC encr-keysize=128 integ-alg=HMAC_SHA2_256_128 prf-alg=PRF_HMAC_SHA2_256 dh-group=CURVE_25519.*child-sas.*rw.*reqid=1 state=INSTALLED mode=TUNNEL protocol=ESP.*encr-alg=AES_CBC encr-keysize=128 integ-alg=HMAC_SHA2_256_128.*local-ts=\[fec1:\:20/128] remote-ts=\[fec2:\:10/124]::YES
+alice::ping6 -c 1 -W 4 -p deadbeef fec2:\:25::From fec0:\:2 icmp_seq=1 Destination unreachable: Address unreachable::YES
+moon::ping6 -c 1 -W 4 -p deadbeef fec2:\:22::From fec2:\:10 icmp_seq=1 Destination unreachable: Address unreachable::YES
+# test other types of ICMPs with venus
+venus::ping6 -c 1 fec2:\:10::64 bytes from fec2:\:10: icmp_.eq=1::YES
+venus::ping6 -t 2 -c 1 fec2:\:10::From fec0:\:2.*Time exceeded: Hop limit::YES
+venus::ping6 -M do -s 1320 -c 1 fec2:\:10::From fec0:\:2.*Packet too big: mtu=1280::YES
+sun::tcpdump::IP6 ip6-moon.strongswan.org > ip6-sun.strongswan.org: ESP::2
+sun::tcpdump::IP6 ip6-sun.strongswan.org > ip6-moon.strongswan.org: ESP::2
+sun::tcpdump::IP6 ip6-sun.strongswan.org > ip6-alice.strongswan.org: ICMP6, destination unreachable, unreachable address fec2:\:25::NO
+sun::tcpdump::IP6 ip6-bob.strongswan.org > ip6-moon1.strongswan.org: ICMP6, destination unreachable, unreachable address fec2:\:22::NO
+venus::tcpdump::IP6 ip6-venus.strongswan.org > ip6-moon1.strongswan.org: ESP::3
+venus::tcpdump::IP6 ip6-moon1.strongswan.org > ip6-venus.strongswan.org: ESP::3
@@ -0,0 +1,55 @@
+*filter
+
+# default policy is DROP
+-P INPUT DROP
+-P OUTPUT DROP
+-P FORWARD DROP
+
+# allow esp
+-A INPUT  -i eth0 -p 50 -j ACCEPT
+-A OUTPUT -o eth0 -p 50 -j ACCEPT
+
+# allow IKE
+-A INPUT  -i eth0 -p udp --sport 500 --dport 500 -j ACCEPT
+-A OUTPUT -o eth0 -p udp --dport 500 --sport 500 -j ACCEPT
+
+# allow MobIKE
+-A INPUT  -i eth0 -p udp --sport 4500 --dport 4500 -j ACCEPT
+-A OUTPUT -o eth0 -p udp --dport 4500 --sport 4500 -j ACCEPT
+
+# allow last UDP fragment
+-A INPUT -i eth0 -p udp -m frag --fraglast -j ACCEPT
+
+# allow ICMPv6 neighbor-solicitations
+-A INPUT  -p icmpv6 --icmpv6-type neighbor-solicitation -j ACCEPT
+-A OUTPUT -p icmpv6 --icmpv6-type neighbor-solicitation -j ACCEPT
+
+# allow ICMPv6 neighbor-advertisements
+-A INPUT  -p icmpv6 --icmpv6-type neighbor-advertisement -j ACCEPT
+-A OUTPUT -p icmpv6 --icmpv6-type neighbor-advertisement -j ACCEPT
+
+# allow crl and certificate fetch from winnetou
+-A INPUT  -i eth0 -p tcp --sport 80 -s fec0::15 -j ACCEPT
+-A OUTPUT -o eth0 -p tcp --dport 80 -d fec0::15 -j ACCEPT
+
+# allow decrypted ICMPv6s from any source IP
+-A INPUT -p icmpv6 --icmpv6-type destination-unreachable -m policy --dir in -j ACCEPT
+-A FORWARD -p icmpv6 --icmpv6-type destination-unreachable -m policy --dir in -j ACCEPT
+
+# allow venus to connect and fetch crls
+-A INPUT -i eth1 -p udp --sport 500 --dport 500 -j ACCEPT
+-A OUTPUT -o eth1 -p udp --dport 500 --sport 500 -j ACCEPT
+-A INPUT -i eth1 -p 50 -j ACCEPT
+-A OUTPUT -o eth1 -p 50 -j ACCEPT
+-A FORWARD -i eth0 -o eth1 -p tcp --sport 80 -s fec0::15 -j ACCEPT
+-A FORWARD -o eth0 -i eth1 -p tcp --dport 80 -d fec0::15 -j ACCEPT
+
+# forward specific errors to venus
+-A FORWARD -d fec1::20/128 -p icmpv6 --icmpv6-type time-exceeded -j ACCEPT
+-A FORWARD -d fec1::20/128 -p icmpv6 --icmpv6-type packet-too-big -j ACCEPT
+
+# log dropped packets
+-A INPUT  -j LOG --log-prefix " IN: "
+-A OUTPUT -j LOG --log-prefix " OUT: "
+
+COMMIT
@@ -0,0 +1,10 @@
+# /etc/strongswan.conf - strongSwan configuration file
+
+swanctl {
+  load = pem pkcs1 pubkey openssl random
+}
+
+charon-systemd {
+  load = random nonce openssl pem pkcs1 curl revocation vici kernel-netlink socket-default updown
+  fragment_size = 1400
+}
@@ -0,0 +1,55 @@
+connections {
+
+   net-net {
+      local_addrs  = fec0::1
+      remote_addrs = fec0::2
+
+      local {
+         auth = pubkey
+         certs = moonCert.pem
+         id = moon.strongswan.org
+      }
+      remote {
+         auth = pubkey
+         id = sun.strongswan.org
+      }
+      children {
+         net-net {
+            local_ts  = fec1::0/16
+            remote_ts = fec2::0/16
+            icmp = yes
+
+            updown = /usr/local/libexec/ipsec/_updown iptables
+            hostaccess = yes
+            esp_proposals = aes128-sha256-x25519
+         }
+      }
+      version = 2
+      mobike = no
+      proposals = aes128-sha256-x25519
+   }
+
+   venus : connections.net-net {
+      local_addrs = fec1::1
+      remote_addrs = fec1::20
+
+      remote {
+         id = venus.strongswan.org
+      }
+      children {
+         net-net {
+            # exclude sun but include bob
+            local_ts  = fec2::10/124
+            remote_ts = dynamic
+            hostaccess = no
+         }
+      }
+   }
+}
+
+authorities {
+   strongswan {
+      cacert = strongswanCert.pem
+      crl_uris = http://ip6-winnetou.strongswan.org/strongswan.crl
+   }
+}
@@ -0,0 +1,49 @@
+*filter
+
+# default policy is DROP
+-P INPUT DROP
+-P OUTPUT DROP
+-P FORWARD DROP
+
+# allow esp
+-A INPUT  -i eth0 -p 50 -j ACCEPT
+-A OUTPUT -o eth0 -p 50 -j ACCEPT
+
+# allow IKE
+-A INPUT  -i eth0 -p udp --sport 500 --dport 500 -j ACCEPT
+-A OUTPUT -o eth0 -p udp --dport 500 --sport 500 -j ACCEPT
+
+# allow MobIKE
+-A INPUT  -i eth0 -p udp --sport 4500 --dport 4500 -j ACCEPT
+-A OUTPUT -o eth0 -p udp --dport 4500 --sport 4500 -j ACCEPT
+
+# allow last UDP fragment
+-A INPUT -i eth0 -p udp -m frag --fraglast -j ACCEPT
+
+# allow ICMPv6 neighbor-solicitations
+-A INPUT  -p icmpv6 --icmpv6-type neighbor-solicitation -j ACCEPT
+-A OUTPUT -p icmpv6 --icmpv6-type neighbor-solicitation -j ACCEPT
+
+# allow ICMPv6 neighbor-advertisements
+-A INPUT  -p icmpv6 --icmpv6-type neighbor-advertisement -j ACCEPT
+-A OUTPUT -p icmpv6 --icmpv6-type neighbor-advertisement -j ACCEPT
+
+# allow crl and certificate fetch from winnetou
+-A INPUT  -i eth0 -p tcp --sport 80 -s fec0::15 -j ACCEPT
+-A OUTPUT -o eth0 -p tcp --dport 80 -d fec0::15 -j ACCEPT
+
+# explicitly allow ICMPv6 responses we don't actually want to see as they should get encrypted
+-A OUTPUT -p icmpv6 --icmpv6-type destination-unreachable -j ACCEPT
+-A FORWARD -p icmpv6 --icmpv6-type destination-unreachable -j ACCEPT
+
+# allow only specific ICMPs from/to venus for this scenario
+-A FORWARD -s fec1::20/128 -p icmpv6 --icmpv6-type echo-request -j ACCEPT
+-A FORWARD -d fec1::20/128 -p icmpv6 --icmpv6-type echo-reply -j ACCEPT
+-A OUTPUT -d fec1::20/128 -p icmpv6 --icmpv6-type time-exceeded -j ACCEPT
+-A OUTPUT -d fec1::20/128 -p icmpv6 --icmpv6-type packet-too-big -j ACCEPT
+
+# log dropped packets
+-A INPUT  -j LOG --log-prefix " IN: "
+-A OUTPUT -j LOG --log-prefix " OUT: "
+
+COMMIT
@@ -0,0 +1,10 @@
+# /etc/strongswan.conf - strongSwan configuration file
+
+swanctl {
+  load = pem pkcs1 pubkey openssl random
+}
+
+charon-systemd {
+  load = random nonce openssl pem pkcs1 curl revocation vici kernel-netlink socket-default updown
+  fragment_size = 1400
+}
@@ -0,0 +1,38 @@
+connections {
+
+   net-net {
+      local_addrs  = fec0::2
+      remote_addrs = fec0::1
+
+      local {
+         auth = pubkey
+         certs = sunCert.pem
+         id = sun.strongswan.org
+      }
+      remote {
+         auth = pubkey
+         id = moon.strongswan.org
+      }
+      children {
+         net-net {
+            # exclude sun's and bob's IPs
+            local_ts  = fec2::20/124
+            remote_ts = fec1::0/16
+            icmp = yes
+
+            updown = /usr/local/libexec/ipsec/_updown iptables
+            esp_proposals = aes128-sha256-x25519
+         }
+      }
+      version = 2
+      mobike = no
+      proposals = aes128-sha256-x25519
+   }
+}
+
+authorities {
+   strongswan {
+      cacert = strongswanCert.pem
+      crl_uris = http://ip6-winnetou.strongswan.org/strongswan.crl
+   }
+}
@@ -0,0 +1,10 @@
+# /etc/strongswan.conf - strongSwan configuration file
+
+swanctl {
+  load = pem pkcs1 pubkey openssl random
+}
+
+charon-systemd {
+  load = random nonce openssl pem pkcs1 curl revocation vici kernel-netlink socket-default updown
+  fragment_size = 1400
+}
@@ -0,0 +1,37 @@
+connections {
+
+   rw {
+      local_addrs  = fec1::20
+      remote_addrs = fec1::1
+
+      local {
+         auth = pubkey
+         certs = venusCert.pem
+         id = venus.strongswan.org
+      }
+      remote {
+         auth = pubkey
+         id = moon.strongswan.org
+      }
+      children {
+         rw {
+            remote_ts = fec2::0/16
+            icmp = yes
+
+            updown = /usr/local/libexec/ipsec/_updown iptables
+            hostaccess = yes
+            esp_proposals = aes128-sha256-x25519
+         }
+      }
+      version = 2
+      mobike = no
+      proposals = aes128-sha256-x25519
+   }
+}
+
+authorities {
+   strongswan {
+      cacert = strongswanCert.pem
+      crl_uris = http://ip6-winnetou.strongswan.org/strongswan.crl
+   }
+}
@@ -0,0 +1,18 @@
+venus::systemctl stop strongswan
+moon::systemctl stop strongswan
+sun::systemctl stop strongswan
+alice::"ip route del fec2:\:/16 via fec1:\:1"
+venus::"ip route del fec2:\:/16 via fec1:\:1"
+moon::"ip route del fec2:\:/16 via fec0:\:2"
+sun::"ip route del fec1:\:/16 via fec0:\:1"
+bob::"ip route del fec1:\:/16 via fec2:\:1"
+sun::"ip route del fec2:\:20/126 via fec2:\:10"
+sun::"ip route del fec2:\:10/128 dev eth1"
+venus::"ip route del fec0:\:/16 via fec1:\:1"
+winnetou::"ip route del fec1:\:/16 via fec0:\:1"
+venus::iptables-restore < /etc/iptables.flush
+moon::iptables-restore < /etc/iptables.flush
+sun::iptables-restore < /etc/iptables.flush
+venus::ip6tables-restore < /etc/ip6tables.flush
+moon::ip6tables-restore < /etc/ip6tables.flush
+sun::ip6tables-restore < /etc/ip6tables.flush
@@ -0,0 +1,27 @@
+venus::iptables-restore < /etc/iptables.drop
+moon::iptables-restore < /etc/iptables.drop
+sun::iptables-restore < /etc/iptables.drop
+venus::ip6tables-restore < /etc/ip6tables.rules
+moon::ip6tables-restore < /etc/ip6tables.rules
+sun::ip6tables-restore < /etc/ip6tables.rules
+venus::systemctl start --no-block strongswan
+moon::systemctl start --no-block strongswan
+sun::systemctl start --no-block strongswan
+alice::"ip route add fec2:\:/16 via fec1:\:1"
+venus::"ip route add fec2:\:/16 via fec1:\:1"
+moon::"ip route add fec2:\:/16 via fec0:\:2"
+sun::"ip route add fec1:\:/16 via fec0:\:1"
+bob::"ip route add fec1:\:/16 via fec2:\:1"
+venus::"ip route add fec0:\:/16 via fec1:\:1"
+winnetou::"ip route add fec1:\:/16 via fec0:\:1"
+# add a route for part of the private subnet via bob
+sun::"ip route add fec2:\:20/126 via fec2:\:10"
+# force a lower MTU for traffic to bob
+sun::"ip route add fec2:\:10/128 dev eth1 src fec2:\:1 mtu 1280"
+# allow decrypted ICMPv6s from any source IP (rules for sun and moon are in ip6tables.rules)
+venus::ip6tables -A INPUT -p icmpv6 -m policy --dir in -j ACCEPT
+venus::expect-connection rw
+moon::expect-connection net-net
+sun::expect-connection net-net
+moon::swanctl --initiate --child net-net
+venus::swanctl --initiate --child rw
@@ -0,0 +1,29 @@
+#!/bin/bash
+#
+# This configuration file provides information on the
+# guest instances used for this test
+
+# All guest instances that are required for this test
+#
+VIRTHOSTS="alice venus moon winnetou sun bob"
+
+# Corresponding block diagram
+#
+DIAGRAM="a-m-w-s-b-ip6.png"
+
+# Guest instances on which tcpdump is to be started
+#
+TCPDUMPHOSTS="venus sun"
+
+# Guest instances on which IPsec is started
+# Used for IPsec logging purposes
+#
+IPSECHOSTS="venus moon sun"
+
+# IP protocol used by IPsec is IPv6
+#
+IPV6=1
+
+# charon controlled by swanctl
+#
+SWANCTL=1