diff mbox series

[net-next,rfc,7/7] net: rtnetlink: add possibility to use alternative names as message handle

Message ID 20190719110029.29466-8-jiri@resnulli.us
State RFC
Delegated to: David Miller
Headers show
Series net: introduce alternative names for network interfaces | expand

Commit Message

Jiri Pirko July 19, 2019, 11 a.m. UTC 
From: Jiri Pirko <jiri@mellanox.com>

Extend the basic rtnetlink commands to use alternative interface names
as a handle instead of ifindex and ifname.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
---
 net/core/rtnetlink.c | 36 +++++++++++++++++++++++-------------
 1 file changed, 23 insertions(+), 13 deletions(-)

Comments

Jakub Kicinski July 20, 2019, 3:59 a.m. UTC | #1 
On Fri, 19 Jul 2019 13:00:29 +0200, Jiri Pirko wrote:
> diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
> index 1fa30d514e3f..68ad12a7fc4d 100644
> --- a/net/core/rtnetlink.c
> +++ b/net/core/rtnetlink.c
> @@ -1793,6 +1793,8 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
>  	[IFLA_MAX_MTU]		= { .type = NLA_U32 },
>  	[IFLA_ALT_IFNAME_MOD]	= { .type = NLA_STRING,
>  				    .len = ALTIFNAMSIZ - 1 },
> +	[IFLA_ALT_IFNAME]	= { .type = NLA_STRING,
> +				    .len = ALTIFNAMSIZ - 1 },

What's the disadvantage of just letting IFLA_IFNAME to get longer 
on input? Is it just that the handling would be asymmetrical?

>  };
>  
>  static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = {
Jiri Pirko July 20, 2019, 7:22 a.m. UTC | #2 
Sat, Jul 20, 2019 at 05:59:27AM CEST, jakub.kicinski@netronome.com wrote:
>On Fri, 19 Jul 2019 13:00:29 +0200, Jiri Pirko wrote:
>> diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
>> index 1fa30d514e3f..68ad12a7fc4d 100644
>> --- a/net/core/rtnetlink.c
>> +++ b/net/core/rtnetlink.c
>> @@ -1793,6 +1793,8 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
>>  	[IFLA_MAX_MTU]		= { .type = NLA_U32 },
>>  	[IFLA_ALT_IFNAME_MOD]	= { .type = NLA_STRING,
>>  				    .len = ALTIFNAMSIZ - 1 },
>> +	[IFLA_ALT_IFNAME]	= { .type = NLA_STRING,
>> +				    .len = ALTIFNAMSIZ - 1 },
>
>What's the disadvantage of just letting IFLA_IFNAME to get longer 
>on input? Is it just that the handling would be asymmetrical?

Hmm, that might work. But the problem is that sometimes the IFLA_IFNAME
is used as a handle, but sometimes it is used to carry the ifname
(newlink, changename). That might be a bit confusing and the code would
be harder to follow. I don't know...


>
>>  };
>>  
>>  static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = {
>
diff mbox series

Patch

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 1fa30d514e3f..68ad12a7fc4d 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1793,6 +1793,8 @@  static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
 	[IFLA_MAX_MTU]		= { .type = NLA_U32 },
 	[IFLA_ALT_IFNAME_MOD]	= { .type = NLA_STRING,
 				    .len = ALTIFNAMSIZ - 1 },
+	[IFLA_ALT_IFNAME]	= { .type = NLA_STRING,
+				    .len = ALTIFNAMSIZ - 1 },
 };
 
 static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = {
@@ -2767,14 +2769,17 @@  static int do_setlink(const struct sk_buff *skb,
 
 static struct net_device *rtnl_dev_get(struct net *net,
 				       struct nlattr *ifname_attr,
+				       struct nlattr *altifname_attr,
 				       char *ifname)
 {
-	char buffer[IFNAMSIZ];
+	char buffer[ALTIFNAMSIZ];
 
 	if (!ifname) {
 		ifname = buffer;
 		if (ifname_attr)
 			nla_strlcpy(ifname, ifname_attr, IFNAMSIZ);
+		else if (altifname_attr)
+			nla_strlcpy(ifname, altifname_attr, ALTIFNAMSIZ);
 		else
 			return NULL;
 	}
@@ -2810,8 +2815,8 @@  static int rtnl_setlink(struct sk_buff *skb, struct nlmsghdr *nlh,
 	ifm = nlmsg_data(nlh);
 	if (ifm->ifi_index > 0)
 		dev = __dev_get_by_index(net, ifm->ifi_index);
-	else if (tb[IFLA_IFNAME])
-		dev = rtnl_dev_get(net, NULL, ifname);
+	else if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME])
+		dev = rtnl_dev_get(net, NULL, tb[IFLA_ALT_IFNAME], ifname);
 	else
 		goto errout;
 
@@ -2908,8 +2913,9 @@  static int rtnl_dellink(struct sk_buff *skb, struct nlmsghdr *nlh,
 	ifm = nlmsg_data(nlh);
 	if (ifm->ifi_index > 0)
 		dev = __dev_get_by_index(tgt_net, ifm->ifi_index);
-	else if (tb[IFLA_IFNAME])
-		dev = rtnl_dev_get(net, tb[IFLA_IFNAME], NULL);
+	else if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME])
+		dev = rtnl_dev_get(net, tb[IFLA_IFNAME],
+				   tb[IFLA_ALT_IFNAME], NULL);
 	else if (tb[IFLA_GROUP])
 		err = rtnl_group_dellink(tgt_net, nla_get_u32(tb[IFLA_GROUP]));
 	else
@@ -3080,8 +3086,8 @@  static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
 	ifm = nlmsg_data(nlh);
 	if (ifm->ifi_index > 0)
 		dev = __dev_get_by_index(net, ifm->ifi_index);
-	else if (tb[IFLA_IFNAME])
-		dev = rtnl_dev_get(net, NULL, ifname);
+	else if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME])
+		dev = rtnl_dev_get(net, NULL, tb[IFLA_ALT_IFNAME], ifname);
 	else
 		dev = NULL;
 
@@ -3345,6 +3351,7 @@  static int rtnl_valid_getlink_req(struct sk_buff *skb,
 
 		switch (i) {
 		case IFLA_IFNAME:
+		case IFLA_ALT_IFNAME:
 		case IFLA_EXT_MASK:
 		case IFLA_TARGET_NETNSID:
 			break;
@@ -3392,8 +3399,9 @@  static int rtnl_getlink(struct sk_buff *skb, struct nlmsghdr *nlh,
 	ifm = nlmsg_data(nlh);
 	if (ifm->ifi_index > 0)
 		dev = __dev_get_by_index(tgt_net, ifm->ifi_index);
-	else if (tb[IFLA_IFNAME])
-		dev = rtnl_dev_get(tgt_net, tb[IFLA_IFNAME], NULL);
+	else if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME])
+		dev = rtnl_dev_get(tgt_net, tb[IFLA_IFNAME],
+				   tb[IFLA_ALT_IFNAME], NULL);
 	else
 		goto out;
 
@@ -3444,8 +3452,9 @@  static int rtnl_newaltifname(struct sk_buff *skb, struct nlmsghdr *nlh,
 	ifm = nlmsg_data(nlh);
 	if (ifm->ifi_index > 0)
 		dev = __dev_get_by_index(net, ifm->ifi_index);
-	else if (tb[IFLA_IFNAME])
-		dev = rtnl_dev_get(net, tb[IFLA_IFNAME], NULL);
+	else if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME])
+		dev = rtnl_dev_get(net, tb[IFLA_IFNAME],
+				   tb[IFLA_ALT_IFNAME], NULL);
 	else
 		return -EINVAL;
 
@@ -3491,8 +3500,9 @@  static int rtnl_delaltifname(struct sk_buff *skb, struct nlmsghdr *nlh,
 	ifm = nlmsg_data(nlh);
 	if (ifm->ifi_index > 0)
 		dev = __dev_get_by_index(net, ifm->ifi_index);
-	else if (tb[IFLA_IFNAME])
-		dev = rtnl_dev_get(net, tb[IFLA_IFNAME], NULL);
+	else if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME])
+		dev = rtnl_dev_get(net, tb[IFLA_IFNAME],
+				   tb[IFLA_ALT_IFNAME], NULL);
 	else
 		return -EINVAL;