feat: add Conn.CreateTable (#246)

`Conn.AddTable` use netlink.Create which will not emit an error
if the table we want to create already existed,
just like the `nft add table ...` command works.

The caller should use netlink.Excl to
get an EEXIST error for that already existed,

So I add another method `Conn.CreateTable`
which works just like `nft create table ...` command.

Related: #245

Signed-off-by: black-desk <me@black-desk.cn>
This commit is contained in:
black-desk 2023-10-24 14:57:23 +08:00 committed by GitHub
parent 6df7a82bbd
commit 32bfbb6627
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 14 additions and 4 deletions

View File

@ -63,9 +63,7 @@ func (cc *Conn) DelTable(t *Table) {
})
}
// AddTable adds the specified Table. See also
// https://wiki.nftables.org/wiki-nftables/index.php/Configuring_tables
func (cc *Conn) AddTable(t *Table) *Table {
func (cc *Conn) addTable(t *Table, flag netlink.HeaderFlags) *Table {
cc.mu.Lock()
defer cc.mu.Unlock()
data := cc.marshalAttr([]netlink.Attribute{
@ -75,13 +73,25 @@ func (cc *Conn) AddTable(t *Table) *Table {
cc.messages = append(cc.messages, netlink.Message{
Header: netlink.Header{
Type: netlink.HeaderType((unix.NFNL_SUBSYS_NFTABLES << 8) | unix.NFT_MSG_NEWTABLE),
Flags: netlink.Request | netlink.Acknowledge | netlink.Create,
Flags: netlink.Request | netlink.Acknowledge | flag,
},
Data: append(extraHeader(uint8(t.Family), 0), data...),
})
return t
}
// AddTable adds the specified Table, just like `nft add table ...`.
// See also https://wiki.nftables.org/wiki-nftables/index.php/Configuring_tables
func (cc *Conn) AddTable(t *Table) *Table {
return cc.addTable(t, netlink.Create)
}
// CreateTable create the specified Table if it do not existed.
// just like `nft create table ...`.
func (cc *Conn) CreateTable(t *Table) *Table {
return cc.addTable(t, netlink.Excl)
}
// FlushTable removes all rules in all chains within the specified Table. See also
// https://wiki.nftables.org/wiki-nftables/index.php/Configuring_tables#Flushing_tables
func (cc *Conn) FlushTable(t *Table) {