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Merge branch 'pmtu-esp'

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Vadim Fedorenko ays:

====================
Fix PMTU for ESP-in-UDP encapsulation

Bug 213669 uncovered regression in PMTU discovery for UDP-encapsulated
routes and some incorrect usage in udp tunnel fields. This series fixes
problems and also adds such case for selftests

v3:
 - update checking logic to account SCTP use case
v2:
 - remove refactor code that was in first patch
 - move checking logic to __udp{4,6}_lib_err_encap
 - add more tests, especially routed configuration
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2021-07-21 08:50:52 -07:00
commit 3ddaed6b09
4 changed files with 298 additions and 19 deletions
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25
net/ipv4/udp.c
View File

@ -645,10 +645,12 @@ static struct sock *__udp4_lib_err_encap(struct net *net,
const struct iphdr *iph,
struct udphdr *uh,
struct udp_table *udptable,
struct sock *sk,
struct sk_buff *skb, u32 info)
{
int (*lookup)(struct sock *sk, struct sk_buff *skb);
int network_offset, transport_offset;
struct sock *sk;
struct udp_sock *up;
network_offset = skb_network_offset(skb);
transport_offset = skb_transport_offset(skb);
@ -659,18 +661,28 @@ static struct sock *__udp4_lib_err_encap(struct net *net,
/* Transport header needs to point to the UDP header */
skb_set_transport_header(skb, iph->ihl << 2);
if (sk) {
up = udp_sk(sk);
lookup = READ_ONCE(up->encap_err_lookup);
if (lookup && lookup(sk, skb))
sk = NULL;
goto out;
}
sk = __udp4_lib_lookup(net, iph->daddr, uh->source,
iph->saddr, uh->dest, skb->dev->ifindex, 0,
udptable, NULL);
if (sk) {
int (*lookup)(struct sock *sk, struct sk_buff *skb);
struct udp_sock *up = udp_sk(sk);
up = udp_sk(sk);
lookup = READ_ONCE(up->encap_err_lookup);
if (!lookup || lookup(sk, skb))
sk = NULL;
}
out:
if (!sk)
sk = ERR_PTR(__udp4_lib_err_encap_no_sk(skb, info));
@ -707,15 +719,16 @@ int __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
sk = __udp4_lib_lookup(net, iph->daddr, uh->dest,
iph->saddr, uh->source, skb->dev->ifindex,
inet_sdif(skb), udptable, NULL);
if (!sk || udp_sk(sk)->encap_type) {
/* No socket for error: try tunnels before discarding */
sk = ERR_PTR(-ENOENT);
if (static_branch_unlikely(&udp_encap_needed_key)) {
sk = __udp4_lib_err_encap(net, iph, uh, udptable, skb,
sk = __udp4_lib_err_encap(net, iph, uh, udptable, sk, skb,
info);
if (!sk)
return 0;
}
} else
sk = ERR_PTR(-ENOENT);
if (IS_ERR(sk)) {
__ICMP_INC_STATS(net, ICMP_MIB_INERRORS);

25
net/ipv6/udp.c
View File

@ -502,12 +502,14 @@ static struct sock *__udp6_lib_err_encap(struct net *net,
const struct ipv6hdr *hdr, int offset,
struct udphdr *uh,
struct udp_table *udptable,
struct sock *sk,
struct sk_buff *skb,
struct inet6_skb_parm *opt,
u8 type, u8 code, __be32 info)
{
int (*lookup)(struct sock *sk, struct sk_buff *skb);
int network_offset, transport_offset;
struct sock *sk;
struct udp_sock *up;
network_offset = skb_network_offset(skb);
transport_offset = skb_transport_offset(skb);
@ -518,18 +520,28 @@ static struct sock *__udp6_lib_err_encap(struct net *net,
/* Transport header needs to point to the UDP header */
skb_set_transport_header(skb, offset);
if (sk) {
up = udp_sk(sk);
lookup = READ_ONCE(up->encap_err_lookup);
if (lookup && lookup(sk, skb))
sk = NULL;
goto out;
}
sk = __udp6_lib_lookup(net, &hdr->daddr, uh->source,
&hdr->saddr, uh->dest,
inet6_iif(skb), 0, udptable, skb);
if (sk) {
int (*lookup)(struct sock *sk, struct sk_buff *skb);
struct udp_sock *up = udp_sk(sk);
up = udp_sk(sk);
lookup = READ_ONCE(up->encap_err_lookup);
if (!lookup || lookup(sk, skb))
sk = NULL;
}
out:
if (!sk) {
sk = ERR_PTR(__udp6_lib_err_encap_no_sk(skb, opt, type, code,
offset, info));
@ -558,16 +570,17 @@ int __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
sk = __udp6_lib_lookup(net, daddr, uh->dest, saddr, uh->source,
inet6_iif(skb), inet6_sdif(skb), udptable, NULL);
if (!sk || udp_sk(sk)->encap_type) {
/* No socket for error: try tunnels before discarding */
sk = ERR_PTR(-ENOENT);
if (static_branch_unlikely(&udpv6_encap_needed_key)) {
sk = __udp6_lib_err_encap(net, hdr, offset, uh,
udptable, skb,
udptable, sk, skb,
opt, type, code, info);
if (!sk)
return 0;
}
} else
sk = ERR_PTR(-ENOENT);
if (IS_ERR(sk)) {
__ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),

55
tools/testing/selftests/net/nettest.c
View File

@ -11,9 +11,11 @@
#include <sys/socket.h>
#include <sys/wait.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netdb.h>
#include <fcntl.h>
#include <libgen.h>
@ -27,6 +29,10 @@
#include <time.h>
#include <errno.h>
#include <linux/xfrm.h>
#include <linux/ipsec.h>
#include <linux/pfkeyv2.h>
#ifndef IPV6_UNICAST_IF
#define IPV6_UNICAST_IF 76
#endif
@ -114,6 +120,9 @@ struct sock_args {
struct in_addr in;
struct in6_addr in6;
} expected_raddr;
/* ESP in UDP encap test */
int use_xfrm;
};
static int server_mode;
@ -1346,6 +1355,41 @@ static int bind_socket(int sd, struct sock_args *args)
return 0;
}
static int config_xfrm_policy(int sd, struct sock_args *args)
{
struct xfrm_userpolicy_info policy = {};
int type = UDP_ENCAP_ESPINUDP;
int xfrm_af = IP_XFRM_POLICY;
int level = SOL_IP;
if (args->type != SOCK_DGRAM) {
log_error("Invalid socket type. Only DGRAM could be used for XFRM\n");
return 1;
}
policy.action = XFRM_POLICY_ALLOW;
policy.sel.family = args->version;
if (args->version == AF_INET6) {
xfrm_af = IPV6_XFRM_POLICY;
level = SOL_IPV6;
}
policy.dir = XFRM_POLICY_OUT;
if (setsockopt(sd, level, xfrm_af, &policy, sizeof(policy)) < 0)
return 1;
policy.dir = XFRM_POLICY_IN;
if (setsockopt(sd, level, xfrm_af, &policy, sizeof(policy)) < 0)
return 1;
if (setsockopt(sd, IPPROTO_UDP, UDP_ENCAP, &type, sizeof(type)) < 0) {
log_err_errno("Failed to set xfrm encap");
return 1;
}
return 0;
}
static int lsock_init(struct sock_args *args)
{
long flags;
@ -1389,6 +1433,11 @@ static int lsock_init(struct sock_args *args)
if (fcntl(sd, F_SETFD, FD_CLOEXEC) < 0)
log_err_errno("Failed to set close-on-exec flag");
if (args->use_xfrm && config_xfrm_policy(sd, args)) {
log_err_errno("Failed to set xfrm policy");
goto err;
}
out:
return sd;
@ -1772,7 +1821,7 @@ static int ipc_parent(int cpid, int fd, struct sock_args *args)
return client_status;
}
#define GETOPT_STR "sr:l:c:p:t:g:P:DRn:M:X:m:d:I:BN:O:SCi6L:0:1:2:3:Fbq"
#define GETOPT_STR "sr:l:c:p:t:g:P:DRn:M:X:m:d:I:BN:O:SCi6xL:0:1:2:3:Fbq"
static void print_usage(char *prog)
{
@ -1795,6 +1844,7 @@ static void print_usage(char *prog)
" -D|R datagram (D) / raw (R) socket (default stream)\n"
" -l addr local address to bind to in server mode\n"
" -c addr local address to bind to in client mode\n"
" -x configure XFRM policy on socket\n"
"\n"
" -d dev bind socket to given device name\n"
" -I dev bind socket to given device name - server mode\n"
@ -1966,6 +2016,9 @@ int main(int argc, char *argv[])
case 'q':
quiet = 1;
break;
case 'x':
args.use_xfrm = 1;
break;
default:
print_usage(argv[0]);
return 1;

212
tools/testing/selftests/net/pmtu.sh
View File

@ -118,6 +118,16 @@
# below for IPv6 doesn't apply here, because, on IPv4, administrative MTU
# changes alone won't affect PMTU
#
# - pmtu_vti4_udp_exception
# Same as pmtu_vti4_exception, but using ESP-in-UDP
#
# - pmtu_vti4_udp_routed_exception
# Set up vti tunnel on top of veth connected through routing namespace and
# add xfrm states and policies with ESP-in-UDP encapsulation. Check that
# route exception is not created if link layer MTU is not exceeded, then
# lower MTU on second part of routed environment and check that exception
# is created with the expected PMTU.
#
# - pmtu_vti6_exception
# Set up vti6 tunnel on top of veth, with xfrm states and policies, in two
# namespaces with matching endpoints. Check that route exception is
@ -125,6 +135,13 @@
# decrease and increase MTU of tunnel, checking that route exception PMTU
# changes accordingly
#
# - pmtu_vti6_udp_exception
# Same as pmtu_vti6_exception, but using ESP-in-UDP
#
# - pmtu_vti6_udp_routed_exception
# Same as pmtu_vti6_udp_routed_exception but with routing between vti
# endpoints
#
# - pmtu_vti4_default_mtu
# Set up vti4 tunnel on top of veth, in two namespaces with matching
# endpoints. Check that MTU assigned to vti interface is the MTU of the
@ -224,6 +241,10 @@ tests="
pmtu_ipv6_ipv6_exception IPv6 over IPv6: PMTU exceptions 1
pmtu_vti6_exception vti6: PMTU exceptions 0
pmtu_vti4_exception vti4: PMTU exceptions 0
pmtu_vti6_udp_exception vti6: PMTU exceptions (ESP-in-UDP) 0
pmtu_vti4_udp_exception vti4: PMTU exceptions (ESP-in-UDP) 0
pmtu_vti6_udp_routed_exception vti6: PMTU exceptions, routed (ESP-in-UDP) 0
pmtu_vti4_udp_routed_exception vti4: PMTU exceptions, routed (ESP-in-UDP) 0
pmtu_vti4_default_mtu vti4: default MTU assignment 0
pmtu_vti6_default_mtu vti6: default MTU assignment 0
pmtu_vti4_link_add_mtu vti4: MTU setting on link creation 0
@ -246,7 +267,6 @@ ns_b="ip netns exec ${NS_B}"
ns_c="ip netns exec ${NS_C}"
ns_r1="ip netns exec ${NS_R1}"
ns_r2="ip netns exec ${NS_R2}"
# Addressing and routing for tests with routers: four network segments, with
# index SEGMENT between 1 and 4, a common prefix (PREFIX4 or PREFIX6) and an
# identifier ID, which is 1 for hosts (A and B), 2 for routers (R1 and R2).
@ -279,7 +299,6 @@ routes="
A ${prefix6}:${b_r2}::1 ${prefix6}:${a_r2}::2
B default ${prefix6}:${b_r1}::2
"
USE_NH="no"
# ns family nh id destination gateway
nexthops="
@ -326,6 +345,7 @@ dummy6_mask="64"
err_buf=
tcpdump_pids=
nettest_pids=
err() {
err_buf="${err_buf}${1}
@ -548,6 +568,14 @@ setup_vti6() {
setup_vti 6 ${veth6_a_addr} ${veth6_b_addr} ${tunnel6_a_addr} ${tunnel6_b_addr} ${tunnel6_mask}
}
setup_vti4routed() {
setup_vti 4 ${prefix4}.${a_r1}.1 ${prefix4}.${b_r1}.1 ${tunnel4_a_addr} ${tunnel4_b_addr} ${tunnel4_mask}
}
setup_vti6routed() {
setup_vti 6 ${prefix6}:${a_r1}::1 ${prefix6}:${b_r1}::1 ${tunnel6_a_addr} ${tunnel6_b_addr} ${tunnel6_mask}
}
setup_vxlan_or_geneve() {
type="${1}"
a_addr="${2}"
@ -619,18 +647,36 @@ setup_xfrm() {
proto=${1}
veth_a_addr="${2}"
veth_b_addr="${3}"
encap=${4}
run_cmd ${ns_a} ip -${proto} xfrm state add src ${veth_a_addr} dst ${veth_b_addr} spi 0x1000 proto esp aead 'rfc4106(gcm(aes))' 0x0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f 128 mode tunnel || return 1
run_cmd ${ns_a} ip -${proto} xfrm state add src ${veth_b_addr} dst ${veth_a_addr} spi 0x1001 proto esp aead 'rfc4106(gcm(aes))' 0x0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f 128 mode tunnel
run_cmd ${ns_a} ip -${proto} xfrm state add src ${veth_a_addr} dst ${veth_b_addr} spi 0x1000 proto esp aead 'rfc4106(gcm(aes))' 0x0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f 128 mode tunnel ${encap} || return 1
run_cmd ${ns_a} ip -${proto} xfrm state add src ${veth_b_addr} dst ${veth_a_addr} spi 0x1001 proto esp aead 'rfc4106(gcm(aes))' 0x0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f 128 mode tunnel ${encap}
run_cmd ${ns_a} ip -${proto} xfrm policy add dir out mark 10 tmpl src ${veth_a_addr} dst ${veth_b_addr} proto esp mode tunnel
run_cmd ${ns_a} ip -${proto} xfrm policy add dir in mark 10 tmpl src ${veth_b_addr} dst ${veth_a_addr} proto esp mode tunnel
run_cmd ${ns_b} ip -${proto} xfrm state add src ${veth_a_addr} dst ${veth_b_addr} spi 0x1000 proto esp aead 'rfc4106(gcm(aes))' 0x0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f 128 mode tunnel
run_cmd ${ns_b} ip -${proto} xfrm state add src ${veth_b_addr} dst ${veth_a_addr} spi 0x1001 proto esp aead 'rfc4106(gcm(aes))' 0x0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f 128 mode tunnel
run_cmd ${ns_b} ip -${proto} xfrm state add src ${veth_a_addr} dst ${veth_b_addr} spi 0x1000 proto esp aead 'rfc4106(gcm(aes))' 0x0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f 128 mode tunnel ${encap}
run_cmd ${ns_b} ip -${proto} xfrm state add src ${veth_b_addr} dst ${veth_a_addr} spi 0x1001 proto esp aead 'rfc4106(gcm(aes))' 0x0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f 128 mode tunnel ${encap}
run_cmd ${ns_b} ip -${proto} xfrm policy add dir out mark 10 tmpl src ${veth_b_addr} dst ${veth_a_addr} proto esp mode tunnel
run_cmd ${ns_b} ip -${proto} xfrm policy add dir in mark 10 tmpl src ${veth_a_addr} dst ${veth_b_addr} proto esp mode tunnel
}
setup_nettest_xfrm() {
which nettest >/dev/null
if [ $? -ne 0 ]; then
echo "'nettest' command not found; skipping tests"
return 1
fi
[ ${1} -eq 6 ] && proto="-6" || proto=""
port=${2}
run_cmd ${ns_a} nettest ${proto} -q -D -s -x -p ${port} -t 5 &
nettest_pids="${nettest_pids} $!"
run_cmd ${ns_b} nettest ${proto} -q -D -s -x -p ${port} -t 5 &
nettest_pids="${nettest_pids} $!"
}
setup_xfrm4() {
setup_xfrm 4 ${veth4_a_addr} ${veth4_b_addr}
}
@ -639,6 +685,26 @@ setup_xfrm6() {
setup_xfrm 6 ${veth6_a_addr} ${veth6_b_addr}
}
setup_xfrm4udp() {
setup_xfrm 4 ${veth4_a_addr} ${veth4_b_addr} "encap espinudp 4500 4500 0.0.0.0"
setup_nettest_xfrm 4 4500
}
setup_xfrm6udp() {
setup_xfrm 6 ${veth6_a_addr} ${veth6_b_addr} "encap espinudp 4500 4500 0.0.0.0"
setup_nettest_xfrm 6 4500
}
setup_xfrm4udprouted() {
setup_xfrm 4 ${prefix4}.${a_r1}.1 ${prefix4}.${b_r1}.1 "encap espinudp 4500 4500 0.0.0.0"
setup_nettest_xfrm 4 4500
}
setup_xfrm6udprouted() {
setup_xfrm 6 ${prefix6}:${a_r1}::1 ${prefix6}:${b_r1}::1 "encap espinudp 4500 4500 0.0.0.0"
setup_nettest_xfrm 6 4500
}
setup_routing_old() {
for i in ${routes}; do
[ "${ns}" = "" ] && ns="${i}" && continue
@ -823,6 +889,11 @@ cleanup() {
done
tcpdump_pids=
for pid in ${nettest_pids}; do
kill ${pid}
done
nettest_pids=
for n in ${NS_A} ${NS_B} ${NS_C} ${NS_R1} ${NS_R2}; do
ip netns del ${n} 2> /dev/null
done
@ -1432,6 +1503,135 @@ test_pmtu_vti6_exception() {
return ${fail}
}
test_pmtu_vti4_udp_exception() {
setup namespaces veth vti4 xfrm4udp || return $ksft_skip
trace "${ns_a}" veth_a "${ns_b}" veth_b \
"${ns_a}" vti4_a "${ns_b}" vti4_b
veth_mtu=1500
vti_mtu=$((veth_mtu - 20))
# UDP SPI SN IV ICV pad length next header
esp_payload_rfc4106=$((vti_mtu - 8 - 4 - 4 - 8 - 16 - 1 - 1))
ping_payload=$((esp_payload_rfc4106 - 28))
mtu "${ns_a}" veth_a ${veth_mtu}
mtu "${ns_b}" veth_b ${veth_mtu}
mtu "${ns_a}" vti4_a ${vti_mtu}
mtu "${ns_b}" vti4_b ${vti_mtu}
# Send DF packet without exceeding link layer MTU, check that no
# exception is created
run_cmd ${ns_a} ping -q -M want -i 0.1 -w 1 -s ${ping_payload} ${tunnel4_b_addr}
pmtu="$(route_get_dst_pmtu_from_exception "${ns_a}" ${tunnel4_b_addr})"
check_pmtu_value "" "${pmtu}" "sending packet smaller than PMTU (IP payload length ${esp_payload_rfc4106})" || return 1
# Now exceed link layer MTU by one byte, check that exception is created
# with the right PMTU value
run_cmd ${ns_a} ping -q -M want -i 0.1 -w 1 -s $((ping_payload + 1)) ${tunnel4_b_addr}
pmtu="$(route_get_dst_pmtu_from_exception "${ns_a}" ${tunnel4_b_addr})"
check_pmtu_value "${esp_payload_rfc4106}" "${pmtu}" "exceeding PMTU (IP payload length $((esp_payload_rfc4106 + 1)))"
}
test_pmtu_vti6_udp_exception() {
setup namespaces veth vti6 xfrm6udp || return $ksft_skip
trace "${ns_a}" veth_a "${ns_b}" veth_b \
"${ns_a}" vti6_a "${ns_b}" vti6_b
fail=0
# Create route exception by exceeding link layer MTU
mtu "${ns_a}" veth_a 4000
mtu "${ns_b}" veth_b 4000
mtu "${ns_a}" vti6_a 5000
mtu "${ns_b}" vti6_b 5000
run_cmd ${ns_a} ${ping6} -q -i 0.1 -w 1 -s 60000 ${tunnel6_b_addr}
# Check that exception was created
pmtu="$(route_get_dst_pmtu_from_exception "${ns_a}" ${tunnel6_b_addr})"
check_pmtu_value any "${pmtu}" "creating tunnel exceeding link layer MTU" || return 1
# Decrease tunnel MTU, check for PMTU decrease in route exception
mtu "${ns_a}" vti6_a 3000
pmtu="$(route_get_dst_pmtu_from_exception "${ns_a}" ${tunnel6_b_addr})"
check_pmtu_value "3000" "${pmtu}" "decreasing tunnel MTU" || fail=1
# Increase tunnel MTU, check for PMTU increase in route exception
mtu "${ns_a}" vti6_a 9000
pmtu="$(route_get_dst_pmtu_from_exception "${ns_a}" ${tunnel6_b_addr})"
check_pmtu_value "9000" "${pmtu}" "increasing tunnel MTU" || fail=1
return ${fail}
}
test_pmtu_vti4_udp_routed_exception() {
setup namespaces routing vti4routed xfrm4udprouted || return $ksft_skip
trace "${ns_a}" veth_A-R1 "${ns_b}" veth_B-R1 \
"${ns_a}" vti4_a "${ns_b}" vti4_b
veth_mtu=1500
vti_mtu=$((veth_mtu - 20))
# UDP SPI SN IV ICV pad length next header
esp_payload_rfc4106=$((vti_mtu - 8 - 4 - 4 - 8 - 16 - 1 - 1))
ping_payload=$((esp_payload_rfc4106 - 28))
mtu "${ns_a}" veth_A-R1 ${veth_mtu}
mtu "${ns_r1}" veth_R1-A ${veth_mtu}
mtu "${ns_b}" veth_B-R1 ${veth_mtu}
mtu "${ns_r1}" veth_R1-B ${veth_mtu}
mtu "${ns_a}" vti4_a ${vti_mtu}
mtu "${ns_b}" vti4_b ${vti_mtu}
# Send DF packet without exceeding link layer MTU, check that no
# exception is created
run_cmd ${ns_a} ping -q -M want -i 0.1 -w 1 -s ${ping_payload} ${tunnel4_b_addr}
pmtu="$(route_get_dst_pmtu_from_exception "${ns_a}" ${tunnel4_b_addr})"
check_pmtu_value "" "${pmtu}" "sending packet smaller than PMTU (IP payload length ${esp_payload_rfc4106})" || return 1
# Now decrease link layer MTU by 8 bytes on R1, check that exception is created
# with the right PMTU value
mtu "${ns_r1}" veth_R1-B $((veth_mtu - 8))
run_cmd ${ns_a} ping -q -M want -i 0.1 -w 1 -s $((ping_payload)) ${tunnel4_b_addr}
pmtu="$(route_get_dst_pmtu_from_exception "${ns_a}" ${tunnel4_b_addr})"
check_pmtu_value "$((esp_payload_rfc4106 - 8))" "${pmtu}" "exceeding PMTU (IP payload length $((esp_payload_rfc4106)))"
}
test_pmtu_vti6_udp_routed_exception() {
setup namespaces routing vti6routed xfrm6udprouted || return $ksft_skip
trace "${ns_a}" veth_A-R1 "${ns_b}" veth_B-R1 \
"${ns_a}" vti6_a "${ns_b}" vti6_b
veth_mtu=1500
vti_mtu=$((veth_mtu - 40))
# UDP SPI SN IV ICV pad length next header
esp_payload_rfc4106=$((vti_mtu - 8 - 4 - 4 - 8 - 16 - 1 - 1))
ping_payload=$((esp_payload_rfc4106 - 48))
mtu "${ns_a}" veth_A-R1 ${veth_mtu}
mtu "${ns_r1}" veth_R1-A ${veth_mtu}
mtu "${ns_b}" veth_B-R1 ${veth_mtu}
mtu "${ns_r1}" veth_R1-B ${veth_mtu}
# mtu "${ns_a}" vti6_a ${vti_mtu}
# mtu "${ns_b}" vti6_b ${vti_mtu}
run_cmd ${ns_a} ${ping6} -q -M want -i 0.1 -w 1 -s ${ping_payload} ${tunnel6_b_addr}
# Check that exception was not created
pmtu="$(route_get_dst_pmtu_from_exception "${ns_a}" ${tunnel6_b_addr})"
check_pmtu_value "" "${pmtu}" "sending packet smaller than PMTU (IP payload length ${esp_payload_rfc4106})" || return 1
# Now decrease link layer MTU by 8 bytes on R1, check that exception is created
# with the right PMTU value
mtu "${ns_r1}" veth_R1-B $((veth_mtu - 8))
run_cmd ${ns_a} ${ping6} -q -M want -i 0.1 -w 1 -s $((ping_payload)) ${tunnel6_b_addr}
pmtu="$(route_get_dst_pmtu_from_exception "${ns_a}" ${tunnel6_b_addr})"
check_pmtu_value "$((esp_payload_rfc4106 - 8))" "${pmtu}" "exceeding PMTU (IP payload length $((esp_payload_rfc4106)))"
}
test_pmtu_vti4_default_mtu() {
setup namespaces veth vti4 || return $ksft_skip