Hi,
When we add the same rule again with flag NLM_F_EXCL we expect that we
receive error:
RTNETLINK answers: File exists
This behaviour is already in ip routing part.
I have noticed that iproute2 when adds new rule it attach flag
NLM_F_EXCL to call.
(see
http://git.kernel.org/cgit/linux/kernel/git/shemminger/iproute2.git/tree/ip/iprule.c#n334)
Next thing what I found is that this flag is not handled from kernel side.
I implemented this feature and I tested this with qemu x86 on:
linux-4.5.4
linux (git)
linux-stable (git)
Tested with ipv4 and ipv6.
current behaviour with ipv4:
localhost ~ # ip rule
0: from all lookup local
32766: from all lookup main
32767: from all lookup default
localhost ~ # ip rule add from 10.46.177.97 lookup 104 pref 1005
localhost ~ # ip rule add from 10.46.177.97 lookup 104 pref 1005
localhost ~ # ip rule
0: from all lookup local
1005: from 10.46.177.97 lookup 104
1005: from 10.46.177.97 lookup 104
32766: from all lookup main
32767: from all lookup default
expected behavior after patch:
localhost ~ # ip rule
0: from all lookup local
32766: from all lookup main
32767: from all lookup default
localhost ~ # ip rule add from 10.46.177.97 lookup 104 pref 1005
localhost ~ # ip rule add from 10.46.177.97 lookup 104 pref 1005
RTNETLINK answers: File exists
localhost ~ # ip rule
0: from all lookup local
1005: from 10.46.177.97 lookup 104
32766: from all lookup main
32767: from all lookup default
There was already topic regarding this but I don't see any changes
merged and problem still occurs.
(see http://marc.info/?l=linux-netdev&m=113577886110391&w=2)
--
Best regards,
Mateusz Bajorski
>From 9c3f80dceec414ff31d0c38d0107dec279fc9894 Mon Sep 17 00:00:00 2001
From: Mateusz Bajorski <mateusz.bajor...@nokia.com>
Date: Fri, 20 May 2016 14:29:56 +0200
Subject: [PATCH] Added NLM_F_EXCL support to fib_nl_newrule
Signed-off-by: Mateusz Bajorski <mateusz.bajor...@nokia.com>
---
net/core/fib_rules.c | 41 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index 840aceb..c1bc07cd 100644
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -291,6 +291,47 @@ static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh)
if (err < 0)
goto errout;
+ if (nlh->nlmsg_flags & NLM_F_EXCL) {
+ list_for_each_entry(rule, &ops->rules_list, list) {
+ if (frh->action && (frh->action != rule->action))
+ continue;
+
+ if (frh_get_table(frh, tb) &&
+ (frh_get_table(frh, tb) != rule->table))
+ continue;
+
+ if (tb[FRA_PRIORITY] &&
+ (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
+ continue;
+
+ if (tb[FRA_IIFNAME] &&
+ nla_strcmp(tb[FRA_IIFNAME], rule->iifname))
+ continue;
+
+ if (tb[FRA_OIFNAME] &&
+ nla_strcmp(tb[FRA_OIFNAME], rule->oifname))
+ continue;
+
+ if (tb[FRA_FWMARK] &&
+ (rule->mark != nla_get_u32(tb[FRA_FWMARK])))
+ continue;
+
+ if (tb[FRA_FWMASK] &&
+ (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
+ continue;
+
+ if (tb[FRA_TUN_ID] &&
+ (rule->tun_id != nla_get_be64(tb[FRA_TUN_ID])))
+ continue;
+
+ if (!ops->compare(rule, frh, tb))
+ continue;
+
+ err = -EEXIST;
+ goto errout;
+ }
+ }
+
rule = kzalloc(ops->rule_size, GFP_KERNEL);
if (rule == NULL) {
err = -ENOMEM;
--
2.6.4
