net: Allow changing IPv4 address protocol
Subsystems (4)
cover net: Allow changing IPv4 address protocol
IPv4 and IPv6 addresses can be assigned a protocol value that indicates the provenance of the IP address. The attribute is modeled after ip route protocols, and essentially allows the administrator or userspace stack to tag addresses in some way that makes sense to the actor in question.
When IP address protocol field was added in commit 47f0bd503210 ("net: Add new protocol attribute to IP addresses"), the semantics included the ability to change the protocol for IPv6 addresses, but not for IPv4 addresses. It seems this was not deliberate, but rather by accident.
One particular use case is tagging the addresses differently depending on whether the routing stack should advertise them or not. Without support for protocol replacement, this can not be done.
In this patchset, extend IPv4 to allow changing the protocol defined at an address (in patch #1). Then in patches #2 and #3 add selftest coverage for ip address protocols.
Currently the kernel simply ignores the new value. Thus allowing the replacement changes the observable behavior. However, since IPv6 already behaves like this anyway, and since the feature as such is relatively new, it seems like the change is safe to make.
An example session with the feature in action:
bash-5.2# ip address add dev d 192.0.2.1/28 proto 0xab bash-5.2# ip address show dev d 4: d: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN group default qlen 1000 link/ether 06:29:74:fd:1f:eb brd ff:ff:ff:ff:ff:ff inet 192.0.2.1/28 scope global proto 0xab d valid_lft forever preferred_lft forever bash-5.2# ip address replace dev d 192.0.2.1/28 proto 0x11 bash-5.2# ip address show dev d 4: d: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN group default qlen 1000 link/ether 06:29:74:fd:1f:eb brd ff:ff:ff:ff:ff:ff inet 192.0.2.1/28 scope global proto 0x11 d valid_lft forever preferred_lft forever
Petr Machata (3):
net: ipv4: Allow changing IPv4 address protocol
selftests: rtnetlink: Make the set of tests to run configurable
selftests: rtnetlink: Add an address proto test
net/ipv4/devinet.c | 3 + tools/testing/selftests/net/rtnetlink.sh | 181 +++++++++++++++++------ 2 files changed, 142 insertions(+), 42 deletions(-)
Signature · 1 line
2.39.0
PATCH 1/3 net: ipv4: Allow changing IPv4 address protocol
When IP address protocol field was added in commit 47f0bd503210 ("net: Add new protocol attribute to IP addresses"), the semantics included the ability to change the protocol for IPv6 addresses, but not for IPv4 addresses. It seems this was not deliberate, but rather by accident.
A userspace that wants to change the protocol of an address might drop and recreate the address, but that disrupts routing and is just impractical.
So in this patch, when an IPv4 address is replaced (through RTM_NEWADDR request with NLM_F_REPLACE flag), update the proto at the address to the one given in the request, or zero if none is given. This matches the behavior of IPv6. Previously, any new value given was simply ignored.
--- net/ipv4/devinet.c | 3 +++ 1 file changed, 3 insertions(+)
net/ipv4/devinet.c +3 -0
@@ -962,6 +962,7 @@ static int inet_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh, extack); }else {u32 new_metric = ifa->ifa_rt_priority; +u8 new_proto = ifa->ifa_proto;inet_free_ifa (ifa);
@@ -975,6 +976,8 @@ static int inet_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh, ifa->ifa_rt_priority = new_metric; } + ifa->ifa_proto = new_proto; +set_ifa_lifetime (ifa, valid_lft, prefered_lft);cancel_delayed_work (&check_lifetime_work); queue_delayed_work(system_power_efficient_wq,
Signature · 1 line
2.39.0
Re: [PATCH net-next 1/3] net: ipv4: Allow changing IPv4 address protocol
Quoted 13 lines · Petr Machata
When IP address protocol field was added in commit
47f0bd503210("net: Add new protocol attribute to IP addresses"), the semantics included the ability to change the protocol for IPv6 addresses, but not for IPv4 addresses. It seems this was not deliberate, but rather by accident.A userspace that wants to change the protocol of an address might drop and recreate the address, but that disrupts routing and is just impractical.
So in this patch, when an IPv4 address is replaced (through
RTM_NEWADDRrequest withNLM_F_REPLACEflag), update the proto at the address to the one given in the request, or zero if none is given. This matches the behavior of IPv6. Previously, any new value given was simply ignored.
Quoted 6 lines
Signed-off-by Petr Machata <[email protected]>Reviewed-by Ido Schimmel <[email protected]>--- net/ipv4/devinet.c | 3 +++ 1 file changed, 3 insertions(+)
PATCH 2/3 selftests: rtnetlink: Make the set of tests to run configurable
In reply to Petr MachataExtract the list of all tests into a variable, ALL_TESTS. Then assume the environment variable TESTS holds the list of tests to actually run, falling back to ALL_TESTS if TESTS is empty. This is the same interface that forwarding selftests use to make the set of tests to run configurable. In addition to this, allow setting the value explicitly through a command line option "-t" along the lines of what fib_nexthops.sh does.
--- tools/testing/selftests/net/rtnetlink.sh | 90 +++++++++++++----------- 1 file changed, 48 insertions(+), 42 deletions(-)
tools/testing/selftests/net/rtnetlink.sh +48 -42
@@ -4,6 +4,30 @@ # # set -e +ALL_TESTS=" + kci_test_polrouting + kci_test_route_get + kci_test_addrlft + kci_test_promote_secondaries + kci_test_tc + kci_test_gre + kci_test_gretap + kci_test_ip6gretap + kci_test_erspan + kci_test_ip6erspan + kci_test_bridge + kci_test_addrlabel + kci_test_ifalias + kci_test_vrf + kci_test_encap + kci_test_macsec + kci_test_ipsec + kci_test_ipsec_offload + kci_test_fdb_get + kci_test_neigh_get + kci_test_bridge_parent_id +" + devdummy="test-dummy0" # Kselftest framework requirement - SKIP code is 4.
@@ -1227,60 +1251,34 @@ kci_test_bridge_parent_id() kci_test_rtnl() { + local current_test local ret=0 + kci_add_dummy if [ $ret -ne 0 ];then echo "FAIL: cannot add dummy interface" return 1 fi - kci_test_polrouting - check_err $? - kci_test_route_get - check_err $? - kci_test_addrlft - check_err $? - kci_test_promote_secondaries - check_err $? - kci_test_tc - check_err $? - kci_test_gre - check_err $? - kci_test_gretap - check_err $? - kci_test_ip6gretap - check_err $? - kci_test_erspan - check_err $? - kci_test_ip6erspan - check_err $? - kci_test_bridge - check_err $? - kci_test_addrlabel - check_err $? - kci_test_ifalias - check_err $? - kci_test_vrf - check_err $? - kci_test_encap - check_err $? - kci_test_macsec - check_err $? - kci_test_ipsec - check_err $? - kci_test_ipsec_offload - check_err $? - kci_test_fdb_get - check_err $? - kci_test_neigh_get - check_err $? - kci_test_bridge_parent_id - check_err $? + for current_test in ${TESTS:-$ALL_TESTS}; do + $current_test + check_err $? + done kci_del_dummy return $ret } +usage() +{ + cat <<EOF +usage: ${0##*/} OPTS + + -t <test> Test(s) to run (default: all) + (options: $(echo $ALL_TESTS)) +EOF +} + #check for needed privileges if [ "$(id -u)" -ne 0 ];then echo "SKIP: Need root privileges"
@@ -1295,6 +1293,14 @@ for x in ip tc;do fi done +while getopts t:h o; do + case $o in + t) TESTS=$OPTARG;; + h) usage; exit 0;; + *) usage; exit 1;; + esac +done + kci_test_rtnl exit $?
Signature · 1 line
2.39.0
PATCH 3/3 selftests: rtnetlink: Add an address proto test
In reply to Petr MachataAdd coverage of "ip address {add,replace} ... proto" support.
--- tools/testing/selftests/net/rtnetlink.sh | 91 ++++++++++++++++++++++++ 1 file changed, 91 insertions(+)
tools/testing/selftests/net/rtnetlink.sh +91 -0
@@ -26,6 +26,7 @@ ALL_TESTS=" kci_test_fdb_get kci_test_neigh_get kci_test_bridge_parent_id + kci_test_address_proto " devdummy="test-dummy0"
@@ -1249,6 +1250,96 @@ kci_test_bridge_parent_id() echo "PASS: bridge_parent_id" } +address_get_proto() +{ + local addr=$1; shift + + ip -N -j address show dev "$devdummy" | + jq -e -r --arg addr "${addr%/*}" \ + '.[].addr_info[] | select(.local == $addr) | .protocol' +} + +address_count() +{ + ip -N -j address show dev "$devdummy" "$@" | + jq -e -r '[.[].addr_info[] | .local | select(. != null)] | length' +} + +do_test_address_proto() +{ + local what=$1; shift + local addr=$1; shift + local addr2=${addr%/*}2/${addr#*/} + local addr3=${addr%/*}3/${addr#*/} + local proto + local count + local ret=0 + local err + + ip address add dev "$devdummy" "$addr3" + check_err $? + proto=$(address_get_proto "$addr3") + [[ "$proto" == null ]] + check_err $? + + ip address add dev "$devdummy" "$addr2" proto 0x99 + check_err $? + proto=$(address_get_proto "$addr2") + [[ "$proto" == 0x99 ]] + check_err $? + + ip address add dev "$devdummy" "$addr" proto 0xab + check_err $? + proto=$(address_get_proto "$addr") + [[ "$proto" == 0xab ]] + check_err $? + + ip address replace dev "$devdummy" "$addr" proto 0x11 + proto=$(address_get_proto "$addr") + check_err $? + [[ "$proto" == 0x11 ]] + check_err $? + + count=$(address_count) + check_err $? + (( count == 3 )) # $addr, $addr2 and $addr3 + + count=$(address_count proto 0) + check_err $? + (( count == 1 )) # just $addr2 + + count=$(address_count proto 0x11) + check_err $? + (( count == 2 )) # $addr and $addr2 + + count=$(address_count proto 0xab) + check_err $? + (( count == 1 )) # just $addr2 + + ip address del dev "$devdummy" "$addr" + ip address del dev "$devdummy" "$addr2" + ip address del dev "$devdummy" "$addr3" + + if [ $ret -ne 0 ]; then + echo "FAIL: address proto $what" + return 1 + fi + echo "PASS: address proto $what" +} + +kci_test_address_proto() +{ + local ret=0 + + do_test_address_proto IPv4 192.0.2.1/28 + check_err $? + + do_test_address_proto IPv6 2001:db8:1::1/64 + check_err $? + + return $ret +} + kci_test_rtnl() { local current_test
Signature · 1 line
2.39.0
Re: [PATCH net-next 3/3] selftests: rtnetlink: Add an address proto test
Quoted 8 lines · Petr Machata
Add coverage of "ip address {add,replace} ... proto" support.
Signed-off-by Petr Machata <[email protected]>Reviewed-by Ido Schimmel <[email protected]>--- tools/testing/selftests/net/rtnetlink.sh | 91 ++++++++++++++++++++++++ 1 file changed, 91 insertions(+)
This series was applied to netdev/net-next.git (main) by David S. Miller <[email protected]>:
Hello:
This series was applied to netdev/net-next.git (main) by David S. Miller <[email protected]>:
Quoted 11 lines · On Tue, 21 Mar 2023 12:51:58 +0100 you wrote:
IPv4 and IPv6 addresses can be assigned a protocol value that indicates the provenance of the IP address. The attribute is modeled after ip route protocols, and essentially allows the administrator or userspace stack to tag addresses in some way that makes sense to the actor in question.
When IP address protocol field was added in commit
47f0bd503210("net: Add new protocol attribute to IP addresses"), the semantics included the ability to change the protocol for IPv6 addresses, but not for IPv4 addresses. It seems this was not deliberate, but rather by accident.[...]
Here is the summary with links:
- [net-next,1/3] net: ipv4: Allow changing IPv4 address protocol
https://git.kernel.org/netdev/net-next/c/5c4a9aa856c7 - [net-next,2/3] selftests: rtnetlink: Make the set of tests to run configurable https://git.kernel.org/netdev/net-next/c/ecb3c1e675c7 - [net-next,3/3] selftests: rtnetlink: Add an address proto test https://git.kernel.org/netdev/net-next/c/6a414fd77f61
You are awesome, thank you!
Signature · 2 lines
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