From a43cc8d53096de069fab5d9bf1a2cc7b655c21c7 Mon Sep 17 00:00:00 2001
From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Tue, 6 Mar 2018 18:58:29 +0100
Subject: src: support for get element command

You need a Linux kernel >= 4.15 to use this feature.

This patch allows us to dump the content of an existing set.

 # nft list ruleset
 table ip x {
        set x {
                type ipv4_addr
                flags interval
                elements = { 1.1.1.1-2.2.2.2, 3.3.3.3,
                             5.5.5.5-6.6.6.6 }
        }
 }

You check if a single element exists in the set:

 # nft get element x x { 1.1.1.5 }
 table ip x {
        set x {
                type ipv4_addr
                flags interval
                elements = { 1.1.1.1-2.2.2.2 }
        }
 }

Output means '1.1.1.5' belongs to the '1.1.1.1-2.2.2.2' interval.

You can also check for intervals:

 # nft get element x x { 1.1.1.1-2.2.2.2 }
 table ip x {
        set x {
                type ipv4_addr
                flags interval
                elements = { 1.1.1.1-2.2.2.2 }
        }
 }

If you try to check for an element that doesn't exist, an error is
displayed.

 # nft get element x x { 1.1.1.0 }
 Error: Could not receive set elements: No such file or directory
 get element x x { 1.1.1.0 }
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

You can also check for multiple elements in one go:

 # nft get element x x { 1.1.1.5, 5.5.5.10 }
 table ip x {
        set x {
                type ipv4_addr
                flags interval
                elements = { 1.1.1.1-2.2.2.2, 5.5.5.5-6.6.6.6 }
        }
 }

You can also use this to fetch the existing timeout for specific
elements, in case you have a set with timeouts in place:

 # nft get element w z { 2.2.2.2 }
 table ip w {
        set z {
                type ipv4_addr
                timeout 30s
                elements = { 2.2.2.2 expires 17s }
        }
 }

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 src/scanner.l | 1 +
 1 file changed, 1 insertion(+)

(limited to 'src/scanner.l')

diff --git a/src/scanner.l b/src/scanner.l
index 38e92db0..ab10738b 100644
--- a/src/scanner.l
+++ b/src/scanner.l
@@ -274,6 +274,7 @@ addrstring	({macaddr}|{ip4addr}|{ip6addr})
 "create"		{ return CREATE; }
 "insert"		{ return INSERT; }
 "delete"		{ return DELETE; }
+"get"			{ return GET; }
 "list"			{ return LIST; }
 "reset"			{ return RESET; }
 "flush"			{ return FLUSH; }
-- 
cgit v1.2.3