tools/testing/selftests/net/pmtu.sh

   1 #!/bin/sh
   2 # SPDX-License-Identifier: GPL-2.0
   3 #
   4 # Check that route PMTU values match expectations, and that initial device MTU
   5 # values are assigned correctly
   6 #
   7 # Tests currently implemented:
   8 #
   9 # - pmtu_vti4_exception
  10 #       Set up vti tunnel on top of veth, with xfrm states and policies, in two
  11 #       namespaces with matching endpoints. Check that route exception is not
  12 #       created if link layer MTU is not exceeded, then exceed it and check that
  13 #       exception is created with the expected PMTU. The approach described
  14 #       below for IPv6 doesn't apply here, because, on IPv4, administrative MTU
  15 #       changes alone won't affect PMTU
  16 #
  17 # - pmtu_vti6_exception
  18 #       Set up vti6 tunnel on top of veth, with xfrm states and policies, in two
  19 #       namespaces with matching endpoints. Check that route exception is
  20 #       created by exceeding link layer MTU with ping to other endpoint. Then
  21 #       decrease and increase MTU of tunnel, checking that route exception PMTU
  22 #       changes accordingly
  23 #
  24 # - pmtu_vti4_default_mtu
  25 #       Set up vti4 tunnel on top of veth, in two namespaces with matching
  26 #       endpoints. Check that MTU assigned to vti interface is the MTU of the
  27 #       lower layer (veth) minus additional lower layer headers (zero, for veth)
  28 #       minus IPv4 header length
  29 #
  30 # - pmtu_vti6_default_mtu
  31 #       Same as above, for IPv6
  32 #
  33 # - pmtu_vti4_link_add_mtu
  34 #       Set up vti4 interface passing MTU value at link creation, check MTU is
  35 #       configured, and that link is not created with invalid MTU values
  36 #
  37 # - pmtu_vti6_link_add_mtu
  38 #       Same as above, for IPv6
  39 #
  40 # - pmtu_vti6_link_change_mtu
  41 #       Set up two dummy interfaces with different MTUs, create a vti6 tunnel
  42 #       and check that configured MTU is used on link creation and changes, and
  43 #       that MTU is properly calculated instead when MTU is not configured from
  44 #       userspace
  45
  46 # Kselftest framework requirement - SKIP code is 4.
  47 ksft_skip=4
  48
  49 tests="
  50         pmtu_vti6_exception             vti6: PMTU exceptions
  51         pmtu_vti4_exception             vti4: PMTU exceptions
  52         pmtu_vti4_default_mtu           vti4: default MTU assignment
  53         pmtu_vti6_default_mtu           vti6: default MTU assignment
  54         pmtu_vti4_link_add_mtu          vti4: MTU setting on link creation
  55         pmtu_vti6_link_add_mtu          vti6: MTU setting on link creation
  56         pmtu_vti6_link_change_mtu       vti6: MTU changes on link changes"
  57
  58 NS_A="ns-$(mktemp -u XXXXXX)"
  59 NS_B="ns-$(mktemp -u XXXXXX)"
  60 ns_a="ip netns exec ${NS_A}"
  61 ns_b="ip netns exec ${NS_B}"
  62
  63 veth4_a_addr="192.168.1.1"
  64 veth4_b_addr="192.168.1.2"
  65 veth4_mask="24"
  66 veth6_a_addr="fd00:1::a"
  67 veth6_b_addr="fd00:1::b"
  68 veth6_mask="64"
  69
  70 vti4_a_addr="192.168.2.1"
  71 vti4_b_addr="192.168.2.2"
  72 vti4_mask="24"
  73 vti6_a_addr="fd00:2::a"
  74 vti6_b_addr="fd00:2::b"
  75 vti6_mask="64"
  76
  77 dummy6_0_addr="fc00:1000::0"
  78 dummy6_1_addr="fc00:1001::0"
  79 dummy6_mask="64"
  80
  81 cleanup_done=1
  82 err_buf=
  83
  84 err() {
  85         err_buf="${err_buf}${1}
  86 "
  87 }
  88
  89 err_flush() {
  90         echo -n "${err_buf}"
  91         err_buf=
  92 }
  93
  94 setup_namespaces() {
  95         ip netns add ${NS_A} || return 1
  96         ip netns add ${NS_B}
  97 }
  98
  99 setup_veth() {
 100         ${ns_a} ip link add veth_a type veth peer name veth_b || return 1
 101         ${ns_a} ip link set veth_b netns ${NS_B}
 102
 103         ${ns_a} ip addr add ${veth4_a_addr}/${veth4_mask} dev veth_a
 104         ${ns_b} ip addr add ${veth4_b_addr}/${veth4_mask} dev veth_b
 105
 106         ${ns_a} ip addr add ${veth6_a_addr}/${veth6_mask} dev veth_a
 107         ${ns_b} ip addr add ${veth6_b_addr}/${veth6_mask} dev veth_b
 108
 109         ${ns_a} ip link set veth_a up
 110         ${ns_b} ip link set veth_b up
 111 }
 112
 113 setup_vti() {
 114         proto=${1}
 115         veth_a_addr="${2}"
 116         veth_b_addr="${3}"
 117         vti_a_addr="${4}"
 118         vti_b_addr="${5}"
 119         vti_mask=${6}
 120
 121         [ ${proto} -eq 6 ] && vti_type="vti6" || vti_type="vti"
 122
 123         ${ns_a} ip link add vti${proto}_a type ${vti_type} local ${veth_a_addr} remote ${veth_b_addr} key 10 || return 1
 124         ${ns_b} ip link add vti${proto}_b type ${vti_type} local ${veth_b_addr} remote ${veth_a_addr} key 10
 125
 126         ${ns_a} ip addr add ${vti_a_addr}/${vti_mask} dev vti${proto}_a
 127         ${ns_b} ip addr add ${vti_b_addr}/${vti_mask} dev vti${proto}_b
 128
 129         ${ns_a} ip link set vti${proto}_a up
 130         ${ns_b} ip link set vti${proto}_b up
 131
 132         sleep 1
 133 }
 134
 135 setup_vti4() {
 136         setup_vti 4 ${veth4_a_addr} ${veth4_b_addr} ${vti4_a_addr} ${vti4_b_addr} ${vti4_mask}
 137 }
 138
 139 setup_vti6() {
 140         setup_vti 6 ${veth6_a_addr} ${veth6_b_addr} ${vti6_a_addr} ${vti6_b_addr} ${vti6_mask}
 141 }
 142
 143 setup_xfrm() {
 144         proto=${1}
 145         veth_a_addr="${2}"
 146         veth_b_addr="${3}"
 147
 148         ${ns_a} ip -${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
 149         ${ns_a} ip -${proto} xfrm state add src ${veth_b_addr} dst ${veth_a_addr} spi 0x1001 proto esp aead "rfc4106(gcm(aes))" 0x0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f 128 mode tunnel
 150         ${ns_a} ip -${proto} xfrm policy add dir out mark 10 tmpl src ${veth_a_addr} dst ${veth_b_addr} proto esp mode tunnel
 151         ${ns_a} ip -${proto} xfrm policy add dir in mark 10 tmpl src ${veth_b_addr} dst ${veth_a_addr} proto esp mode tunnel
 152
 153         ${ns_b} ip -${proto} xfrm state add src ${veth_a_addr} dst ${veth_b_addr} spi 0x1000 proto esp aead "rfc4106(gcm(aes))" 0x0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f 128 mode tunnel
 154         ${ns_b} ip -${proto} xfrm state add src ${veth_b_addr} dst ${veth_a_addr} spi 0x1001 proto esp aead "rfc4106(gcm(aes))" 0x0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f 128 mode tunnel
 155         ${ns_b} ip -${proto} xfrm policy add dir out mark 10 tmpl src ${veth_b_addr} dst ${veth_a_addr} proto esp mode tunnel
 156         ${ns_b} ip -${proto} xfrm policy add dir in mark 10 tmpl src ${veth_a_addr} dst ${veth_b_addr} proto esp mode tunnel
 157 }
 158
 159 setup_xfrm4() {
 160         setup_xfrm 4 ${veth4_a_addr} ${veth4_b_addr}
 161 }
 162
 163 setup_xfrm6() {
 164         setup_xfrm 6 ${veth6_a_addr} ${veth6_b_addr}
 165 }
 166
 167 setup() {
 168         [ "$(id -u)" -ne 0 ] && echo "  need to run as root" && return $ksft_skip
 169
 170         cleanup_done=0
 171         for arg do
 172                 eval setup_${arg} || { echo "  ${arg} not supported"; return 1; }
 173         done
 174 }
 175
 176 cleanup() {
 177         [ ${cleanup_done} -eq 1 ] && return
 178         ip netns del ${NS_A} 2 > /dev/null
 179         ip netns del ${NS_B} 2 > /dev/null
 180         cleanup_done=1
 181 }
 182
 183 mtu() {
 184         ns_cmd="${1}"
 185         dev="${2}"
 186         mtu="${3}"
 187
 188         ${ns_cmd} ip link set dev ${dev} mtu ${mtu}
 189 }
 190
 191 mtu_parse() {
 192         input="${1}"
 193
 194         next=0
 195         for i in ${input}; do
 196                 [ ${next} -eq 1 ] && echo "${i}" && return
 197                 [ "${i}" = "mtu" ] && next=1
 198         done
 199 }
 200
 201 link_get() {
 202         ns_cmd="${1}"
 203         name="${2}"
 204
 205         ${ns_cmd} ip link show dev "${name}"
 206 }
 207
 208 link_get_mtu() {
 209         ns_cmd="${1}"
 210         name="${2}"
 211
 212         mtu_parse "$(link_get "${ns_cmd}" ${name})"
 213 }
 214
 215 route_get_dst_exception() {
 216         ns_cmd="${1}"
 217         dst="${2}"
 218
 219         ${ns_cmd} ip route get "${dst}"
 220 }
 221
 222 route_get_dst_pmtu_from_exception() {
 223         ns_cmd="${1}"
 224         dst="${2}"
 225
 226         mtu_parse "$(route_get_dst_exception "${ns_cmd}" ${dst})"
 227 }
 228
 229 test_pmtu_vti4_exception() {
 230         setup namespaces veth vti4 xfrm4 || return 2
 231
 232         veth_mtu=1500
 233         vti_mtu=$((veth_mtu - 20))
 234
 235         #                                SPI   SN   IV  ICV   pad length   next header
 236         esp_payload_rfc4106=$((vti_mtu - 4   - 4  - 8 - 16  - 1          - 1))
 237         ping_payload=$((esp_payload_rfc4106 - 28))
 238
 239         mtu "${ns_a}" veth_a ${veth_mtu}
 240         mtu "${ns_b}" veth_b ${veth_mtu}
 241         mtu "${ns_a}" vti4_a ${vti_mtu}
 242         mtu "${ns_b}" vti4_b ${vti_mtu}
 243
 244         # Send DF packet without exceeding link layer MTU, check that no
 245         # exception is created
 246         ${ns_a} ping -q -M want -i 0.1 -w 2 -s ${ping_payload} ${vti4_b_addr} > /dev/null
 247         pmtu="$(route_get_dst_pmtu_from_exception "${ns_a}" ${vti4_b_addr})"
 248         if [ "${pmtu}" != "" ]; then
 249                 err "  unexpected exception created with PMTU ${pmtu} for IP payload length ${esp_payload_rfc4106}"
 250                 return 1
 251         fi
 252
 253         # Now exceed link layer MTU by one byte, check that exception is created
 254         ${ns_a} ping -q -M want -i 0.1 -w 2 -s $((ping_payload + 1)) ${vti4_b_addr} > /dev/null
 255         pmtu="$(route_get_dst_pmtu_from_exception "${ns_a}" ${vti4_b_addr})"
 256         if [ "${pmtu}" = "" ]; then
 257                 err "  exception not created for IP payload length $((esp_payload_rfc4106 + 1))"
 258                 return 1
 259         fi
 260
 261         # ...with the right PMTU value
 262         if [ ${pmtu} -ne ${esp_payload_rfc4106} ]; then
 263                 err "  wrong PMTU ${pmtu} in exception, expected: ${esp_payload_rfc4106}"
 264                 return 1
 265         fi
 266 }
 267
 268 test_pmtu_vti6_exception() {
 269         setup namespaces veth vti6 xfrm6 || return 2
 270         fail=0
 271
 272         # Create route exception by exceeding link layer MTU
 273         mtu "${ns_a}" veth_a 4000
 274         mtu "${ns_b}" veth_b 4000
 275         mtu "${ns_a}" vti6_a 5000
 276         mtu "${ns_b}" vti6_b 5000
 277         ${ns_a} ping6 -q -i 0.1 -w 2 -s 60000 ${vti6_b_addr} > /dev/null
 278
 279         # Check that exception was created
 280         if [ "$(route_get_dst_pmtu_from_exception "${ns_a}" ${vti6_b_addr})" = "" ]; then
 281                 err "  tunnel exceeding link layer MTU didn't create route exception"
 282                 return 1
 283         fi
 284
 285         # Decrease tunnel MTU, check for PMTU decrease in route exception
 286         mtu "${ns_a}" vti6_a 3000
 287
 288         if [ "$(route_get_dst_pmtu_from_exception "${ns_a}" ${vti6_b_addr})" -ne 3000 ]; then
 289                 err "  decreasing tunnel MTU didn't decrease route exception PMTU"
 290                 fail=1
 291         fi
 292
 293         # Increase tunnel MTU, check for PMTU increase in route exception
 294         mtu "${ns_a}" vti6_a 9000
 295         if [ "$(route_get_dst_pmtu_from_exception "${ns_a}" ${vti6_b_addr})" -ne 9000 ]; then
 296                 err "  increasing tunnel MTU didn't increase route exception PMTU"
 297                 fail=1
 298         fi
 299
 300         return ${fail}
 301 }
 302
 303 test_pmtu_vti4_default_mtu() {
 304         setup namespaces veth vti4 || return 2
 305
 306         # Check that MTU of vti device is MTU of veth minus IPv4 header length
 307         veth_mtu="$(link_get_mtu "${ns_a}" veth_a)"
 308         vti4_mtu="$(link_get_mtu "${ns_a}" vti4_a)"
 309         if [ $((veth_mtu - vti4_mtu)) -ne 20 ]; then
 310                 err "  vti MTU ${vti4_mtu} is not veth MTU ${veth_mtu} minus IPv4 header length"
 311                 return 1
 312         fi
 313 }
 314
 315 test_pmtu_vti6_default_mtu() {
 316         setup namespaces veth vti6 || return 2
 317
 318         # Check that MTU of vti device is MTU of veth minus IPv6 header length
 319         veth_mtu="$(link_get_mtu "${ns_a}" veth_a)"
 320         vti6_mtu="$(link_get_mtu "${ns_a}" vti6_a)"
 321         if [ $((veth_mtu - vti6_mtu)) -ne 40 ]; then
 322                 err "  vti MTU ${vti6_mtu} is not veth MTU ${veth_mtu} minus IPv6 header length"
 323                 return 1
 324         fi
 325 }
 326
 327 test_pmtu_vti4_link_add_mtu() {
 328         setup namespaces || return 2
 329
 330         ${ns_a} ip link add vti4_a type vti local ${veth4_a_addr} remote ${veth4_b_addr} key 10
 331         [ $? -ne 0 ] && err "  vti not supported" && return 2
 332         ${ns_a} ip link del vti4_a
 333
 334         fail=0
 335
 336         min=68
 337         max=$((65528 - 20))
 338         # Check invalid values first
 339         for v in $((min - 1)) $((max + 1)); do
 340                 ${ns_a} ip link add vti4_a mtu ${v} type vti local ${veth4_a_addr} remote ${veth4_b_addr} key 10 2>/dev/null
 341                 # This can fail, or MTU can be adjusted to a proper value
 342                 [ $? -ne 0 ] && continue
 343                 mtu="$(link_get_mtu "${ns_a}" vti4_a)"
 344                 if [ ${mtu} -lt ${min} -o ${mtu} -gt ${max} ]; then
 345                         err "  vti tunnel created with invalid MTU ${mtu}"
 346                         fail=1
 347                 fi
 348                 ${ns_a} ip link del vti4_a
 349         done
 350
 351         # Now check valid values
 352         for v in ${min} 1300 ${max}; do
 353                 ${ns_a} ip link add vti4_a mtu ${v} type vti local ${veth4_a_addr} remote ${veth4_b_addr} key 10
 354                 mtu="$(link_get_mtu "${ns_a}" vti4_a)"
 355                 ${ns_a} ip link del vti4_a
 356                 if [ "${mtu}" != "${v}" ]; then
 357                         err "  vti MTU ${mtu} doesn't match configured value ${v}"
 358                         fail=1
 359                 fi
 360         done
 361
 362         return ${fail}
 363 }
 364
 365 test_pmtu_vti6_link_add_mtu() {
 366         setup namespaces || return 2
 367
 368         ${ns_a} ip link add vti6_a type vti6 local ${veth6_a_addr} remote ${veth6_b_addr} key 10
 369         [ $? -ne 0 ] && err "  vti6 not supported" && return 2
 370         ${ns_a} ip link del vti6_a
 371
 372         fail=0
 373
 374         min=68                  # vti6 can carry IPv4 packets too
 375         max=$((65535 - 40))
 376         # Check invalid values first
 377         for v in $((min - 1)) $((max + 1)); do
 378                 ${ns_a} ip link add vti6_a mtu ${v} type vti6 local ${veth6_a_addr} remote ${veth6_b_addr} key 10 2>/dev/null
 379                 # This can fail, or MTU can be adjusted to a proper value
 380                 [ $? -ne 0 ] && continue
 381                 mtu="$(link_get_mtu "${ns_a}" vti6_a)"
 382                 if [ ${mtu} -lt ${min} -o ${mtu} -gt ${max} ]; then
 383                         err "  vti6 tunnel created with invalid MTU ${v}"
 384                         fail=1
 385                 fi
 386                 ${ns_a} ip link del vti6_a
 387         done
 388
 389         # Now check valid values
 390         for v in 68 1280 1300 $((65535 - 40)); do
 391                 ${ns_a} ip link add vti6_a mtu ${v} type vti6 local ${veth6_a_addr} remote ${veth6_b_addr} key 10
 392                 mtu="$(link_get_mtu "${ns_a}" vti6_a)"
 393                 ${ns_a} ip link del vti6_a
 394                 if [ "${mtu}" != "${v}" ]; then
 395                         err "  vti6 MTU ${mtu} doesn't match configured value ${v}"
 396                         fail=1
 397                 fi
 398         done
 399
 400         return ${fail}
 401 }
 402
 403 test_pmtu_vti6_link_change_mtu() {
 404         setup namespaces || return 2
 405
 406         ${ns_a} ip link add dummy0 mtu 1500 type dummy
 407         [ $? -ne 0 ] && err "  dummy not supported" && return 2
 408         ${ns_a} ip link add dummy1 mtu 3000 type dummy
 409         ${ns_a} ip link set dummy0 up
 410         ${ns_a} ip link set dummy1 up
 411
 412         ${ns_a} ip addr add ${dummy6_0_addr}/${dummy6_mask} dev dummy0
 413         ${ns_a} ip addr add ${dummy6_1_addr}/${dummy6_mask} dev dummy1
 414
 415         fail=0
 416
 417         # Create vti6 interface bound to device, passing MTU, check it
 418         ${ns_a} ip link add vti6_a mtu 1300 type vti6 remote ${dummy6_0_addr} local ${dummy6_0_addr}
 419         mtu="$(link_get_mtu "${ns_a}" vti6_a)"
 420         if [ ${mtu} -ne 1300 ]; then
 421                 err "  vti6 MTU ${mtu} doesn't match configured value 1300"
 422                 fail=1
 423         fi
 424
 425         # Move to another device with different MTU, without passing MTU, check
 426         # MTU is adjusted
 427         ${ns_a} ip link set vti6_a type vti6 remote ${dummy6_1_addr} local ${dummy6_1_addr}
 428         mtu="$(link_get_mtu "${ns_a}" vti6_a)"
 429         if [ ${mtu} -ne $((3000 - 40)) ]; then
 430                 err "  vti MTU ${mtu} is not dummy MTU 3000 minus IPv6 header length"
 431                 fail=1
 432         fi
 433
 434         # Move it back, passing MTU, check MTU is not overridden
 435         ${ns_a} ip link set vti6_a mtu 1280 type vti6 remote ${dummy6_0_addr} local ${dummy6_0_addr}
 436         mtu="$(link_get_mtu "${ns_a}" vti6_a)"
 437         if [ ${mtu} -ne 1280 ]; then
 438                 err "  vti6 MTU ${mtu} doesn't match configured value 1280"
 439                 fail=1
 440         fi
 441
 442         return ${fail}
 443 }
 444
 445 trap cleanup EXIT
 446
 447 exitcode=0
 448 desc=0
 449 IFS="
 450 "
 451 for t in ${tests}; do
 452         [ $desc -eq 0 ] && name="${t}" && desc=1 && continue || desc=0
 453
 454         (
 455                 unset IFS
 456                 eval test_${name}
 457                 ret=$?
 458                 cleanup
 459
 460                 if [ $ret -eq 0 ]; then
 461                         printf "TEST: %-60s  [ OK ]\n" "${t}"
 462                 elif [ $ret -eq 1 ]; then
 463                         printf "TEST: %-60s  [FAIL]\n" "${t}"
 464                         err_flush
 465                         exit 1
 466                 elif [ $ret -eq 2 ]; then
 467                         printf "TEST: %-60s  [SKIP]\n" "${t}"
 468                         err_flush
 469                 fi
 470         )
 471         [ $? -ne 0 ] && exitcode=1
 472 done
 473
 474 exit ${exitcode}