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Date: Thu, 19 Sep 2013 09:54:53 -0700
From: Vincent Li <vincent.mc.li@...il.com>
To: Cong Wang <xiyou.wangcong@...il.com>
Cc: "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: add ip to interface as primary ip address, not secondary ip when
there is alreadly primary ip?
thanks for the pointer
'ip addr' indeed has flag IFA_F_SECONDARY for this, but it is not
available for 'ip addr add', so I made a simple patch for iproute2
ip/ipaddress.c as below:
diff --git a/ip/ipaddress.c b/ip/ipaddress.c
index 1c3e4da..b5aa96a 100644
--- a/ip/ipaddress.c
+++ b/ip/ipaddress.c
@@ -1307,6 +1307,11 @@ static int ipaddr_modify(int cmd, int flags,
int argc, char **argv)
invarg("invalid scope value.", *argv);
req.ifa.ifa_scope = scope;
scoped = 1;
+ } else if (strcmp(*argv, "secondary") == 0 ||
+ strcmp(*argv, "temporary") == 0) {
+ req.ifa.ifa_flags |= IFA_F_SECONDARY;
+ } else if (strcmp(*argv, "primary") == 0) {
+ req.ifa.ifa_flags &= ~IFA_F_SECONDARY;
} else if (strcmp(*argv, "dev") == 0) {
NEXT_ARG();
d = *argv;
I also found that I need to patch up the kernel and here is the kernel
patch, it might look silly, but it works as I tested
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index a1b5bcb..2a1d61b 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -440,14 +440,18 @@ static int __inet_insert_ifa(struct in_ifaddr
*ifa, struct nlmsghdr *nlh,
return 0;
}
- ifa->ifa_flags &= ~IFA_F_SECONDARY;
last_primary = &in_dev->ifa_list;
for (ifap = &in_dev->ifa_list; (ifa1 = *ifap) != NULL;
ifap = &ifa1->ifa_next) {
if (!(ifa1->ifa_flags & IFA_F_SECONDARY) &&
- ifa->ifa_scope <= ifa1->ifa_scope)
- last_primary = &ifa1->ifa_next;
+ ifa->ifa_scope <= ifa1->ifa_scope) {
+ if (ifa->ifa_flags & IFA_F_SECONDARY) {
+ last_primary = &ifa1->ifa_next;
+ } else {
+ ifa1->ifa_flags |= IFA_F_SECONDARY;
+ }
+ }
if (ifa1->ifa_mask == ifa->ifa_mask &&
inet_ifa_match(ifa1->ifa_address, ifa)) {
if (ifa1->ifa_local == ifa->ifa_local) {
@@ -458,7 +462,11 @@ static int __inet_insert_ifa(struct in_ifaddr
*ifa, struct nlmsghdr *nlh,
inet_free_ifa(ifa);
return -EINVAL;
}
- ifa->ifa_flags |= IFA_F_SECONDARY;
+ if (ifa->ifa_flags & IFA_F_SECONDARY) {
+ ifa->ifa_flags |= IFA_F_SECONDARY;
+ } else {
+ ifa->ifa_flags &= ~IFA_F_SECONDARY;
+ }
}
}
my test steps:
1
./ip/ip addr add 192.168.1.1/24 scope global secondary dev eth0
./ip/ip adrr show eth0 >> /tmp/ipaddr.txt
2
./ip/ip addr add 192.168.1.2/24 scope global primary dev eth0
./ip/ip addr show eth0 >> /tmp/ipaddr.txt
3
./ip/ip addr add 192.168.1.3/24 scope global primary dev eth0
./ip/ip addr show eth0 >> /tmp/ipaddr.txt
4
./ip/ip addr add 192.168.1.4/24 scope global secondary dev eth0
./ip/ip addr show eth0 >> /tmp/ipaddr.txt
5
./ip/ip addr add 192.168.1.5/24 scope global dev eth0
./ip/ip addr show eth0 >> /tmp/ipaddr.txt
6
./ip/ip addr del 192.168.1.5/24 dev eth0
./ip/ip addr show eth0 >> /tmp/ipaddr.txt
test result for each step
result 1
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
state UP group default qlen 1000
link/ether 52:54:00:e3:8f:33 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.1/24 scope global secondary eth0
valid_lft forever preferred_lft forever
inet6 fe80::5054:ff:fee3:8f33/64 scope link
valid_lft forever preferred_lft forever
result 2
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
state UP group default qlen 1000
link/ether 52:54:00:e3:8f:33 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.2/24 scope global eth0
valid_lft forever preferred_lft forever
inet 192.168.1.1/24 scope global secondary eth0
valid_lft forever preferred_lft forever
inet6 fe80::5054:ff:fee3:8f33/64 scope link
valid_lft forever preferred_lft forever
result 3
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
state UP group default qlen 1000
link/ether 52:54:00:e3:8f:33 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.3/24 scope global eth0
valid_lft forever preferred_lft forever
inet 192.168.1.2/24 scope global secondary eth0
valid_lft forever preferred_lft forever
inet 192.168.1.1/24 scope global secondary eth0
valid_lft forever preferred_lft forever
inet6 fe80::5054:ff:fee3:8f33/64 scope link
valid_lft forever preferred_lft forever
result 4
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
state UP group default qlen 1000
link/ether 52:54:00:e3:8f:33 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.3/24 scope global eth0
valid_lft forever preferred_lft forever
inet 192.168.1.2/24 scope global secondary eth0
valid_lft forever preferred_lft forever
inet 192.168.1.1/24 scope global secondary eth0
valid_lft forever preferred_lft forever
inet 192.168.1.4/24 scope global secondary eth0
valid_lft forever preferred_lft forever
inet6 fe80::5054:ff:fee3:8f33/64 scope link
valid_lft forever preferred_lft forever
result 5
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
state UP group default qlen 1000
link/ether 52:54:00:e3:8f:33 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.5/24 scope global eth0
valid_lft forever preferred_lft forever
inet 192.168.1.3/24 scope global secondary eth0
valid_lft forever preferred_lft forever
inet 192.168.1.2/24 scope global secondary eth0
valid_lft forever preferred_lft forever
inet 192.168.1.1/24 scope global secondary eth0
valid_lft forever preferred_lft forever
inet 192.168.1.4/24 scope global secondary eth0
valid_lft forever preferred_lft forever
inet6 fe80::5054:ff:fee3:8f33/64 scope link
valid_lft forever preferred_lft forever
result 6
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
state UP group default qlen 1000
link/ether 52:54:00:e3:8f:33 brd ff:ff:ff:ff:ff:ff
inet6 fe80::5054:ff:fee3:8f33/64 scope link
valid_lft forever preferred_lft forever
it does seems to achieve what I wanted, any comment on this?
On Tue, Sep 17, 2013 at 5:29 PM, Cong Wang <xiyou.wangcong@...il.com> wrote:
> On Tue, 17 Sep 2013 at 22:31 GMT, Vincent Li <vincent.mc.li@...il.com> wrote:
>>
>> ideally though, we would like to have the capability in
>> kernel/userspace to specify a flag or something to add any ip as
>> primary even if there is already existing primary ip address (could
>> downgrade the existing primary to secondary ip). does this make sense
>> ?
>
> 'ip addr' already has flags for this.
>
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