diff mbox series

[v3,net-next,1/4] rtnetlink: enable alt_ifname for setlink/newlink

Message ID 20220405134237.16533-1-florent.fourcot@wifirst.fr (mailing list archive)
State Changes Requested
Delegated to: Netdev Maintainers
Headers show
Series [v3,net-next,1/4] rtnetlink: enable alt_ifname for setlink/newlink | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter warning Series does not have a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 2 this patch: 2
netdev/cc_maintainers fail 5 maintainers not CCed: davem@davemloft.net petrm@nvidia.com pabeni@redhat.com idosch@nvidia.com kuba@kernel.org
netdev/build_clang success Errors and warnings before: 9 this patch: 9
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 2 this patch: 2
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 159 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Florent Fourcot April 5, 2022, 1:42 p.m. UTC 
buffer called "ifname" given in function rtnl_dev_get
is always valid when called by setlink/newlink,
but contains only empty string when IFLA_IFNAME is not given. So
IFLA_ALT_IFNAME is always ignored

This patch fixes rtnl_dev_get function with a remove of ifname argument,
and move ifname copy in do_setlink when required.

It extends feature of commit 76c9ac0ee878,
"net: rtnetlink: add possibility to use alternative names as message
handle""

Changes in v2:
 * Remove ifname argument in rtnl_dev_get/do_setlink
   functions (simplify code)

Changes in v3:
 * Simplify rtnl_dev_get signature

CC: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Florent Fourcot <florent.fourcot@wifirst.fr>
Signed-off-by: Brian Baboch <brian.baboch@wifirst.fr>
---
 net/core/rtnetlink.c | 69 +++++++++++++++++++-------------------------
 1 file changed, 29 insertions(+), 40 deletions(-)

Comments

Jakub Kicinski April 6, 2022, 12:41 a.m. UTC | #1 
On Tue,  5 Apr 2022 15:42:34 +0200 Florent Fourcot wrote:
> buffer called "ifname" given in function rtnl_dev_get
> is always valid when called by setlink/newlink,
> but contains only empty string when IFLA_IFNAME is not given. So
> IFLA_ALT_IFNAME is always ignored
> 
> This patch fixes rtnl_dev_get function with a remove of ifname argument,
> and move ifname copy in do_setlink when required.
> 
> It extends feature of commit 76c9ac0ee878,
> "net: rtnetlink: add possibility to use alternative names as message
> handle""
> 
> Changes in v2:
>  * Remove ifname argument in rtnl_dev_get/do_setlink
>    functions (simplify code)
> 
> Changes in v3:
>  * Simplify rtnl_dev_get signature
> 
> CC: Jiri Pirko <jiri@mellanox.com>
> Signed-off-by: Florent Fourcot <florent.fourcot@wifirst.fr>
> Signed-off-by: Brian Baboch <brian.baboch@wifirst.fr>

This patch needs to be after patch 3, AFAICT. Otherwise someone running
a bisection and landing in between the two will have a buggy build.

Please provide a cover letter for the series, now that it's 4 patches.
Florent Fourcot April 7, 2022, 12:34 p.m. UTC | #2 
Hello,

> 
> This patch needs to be after patch 3, AFAICT. Otherwise someone running
> a bisection and landing in between the two will have a buggy build.
> 

I double checked and this patch compiles perfectly fine when applied 
first, at least with my .config.
Could you be more specific on what I'm missing?

> Please provide a cover letter for the series, now that it's 4 patches.

Thank you, done. I made a typo on it (v3 instead of v4) so do not 
hesitate to tell me if I should resubmit again.

Best regards,
Jakub Kicinski April 7, 2022, 4:11 p.m. UTC | #3 
On Thu, 7 Apr 2022 14:34:33 +0200 Florent Fourcot wrote:
> > This patch needs to be after patch 3, AFAICT. Otherwise someone running
> > a bisection and landing in between the two will have a buggy build.
> 
> I double checked and this patch compiles perfectly fine when applied 
> first, at least with my .config.
> Could you be more specific on what I'm missing?

rtnl_group_changelink() was passing NULL as ifname, but with just 
this patch applied we'll start using tb[IFLA_IFNAME] directly. 

It's better to have your patch which rejects group settings with
tb[IFLA_IFNAME] first, to avoid changing the group + IFLA_IFNAME
behavior subtly multiple times.
diff mbox series

Patch

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 159c9c61e6af..6a5764745288 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2607,17 +2607,23 @@  static int do_set_proto_down(struct net_device *dev,
 static int do_setlink(const struct sk_buff *skb,
 		      struct net_device *dev, struct ifinfomsg *ifm,
 		      struct netlink_ext_ack *extack,
-		      struct nlattr **tb, char *ifname, int status)
+		      struct nlattr **tb, int status)
 {
 	const struct net_device_ops *ops = dev->netdev_ops;
+	char ifname[IFNAMSIZ];
 	int err;
 
 	err = validate_linkmsg(dev, tb, extack);
 	if (err < 0)
 		return err;
 
+	if (tb[IFLA_IFNAME])
+		nla_strscpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);
+	else
+		ifname[0] = '\0';
+
 	if (tb[IFLA_NET_NS_PID] || tb[IFLA_NET_NS_FD] || tb[IFLA_TARGET_NETNSID]) {
-		const char *pat = ifname && ifname[0] ? ifname : NULL;
+		const char *pat = ifname[0] ? ifname : NULL;
 		struct net *net;
 		int new_ifindex;
 
@@ -2973,21 +2979,16 @@  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[ALTIFNAMSIZ];
-
-	if (!ifname) {
-		ifname = buffer;
-		if (ifname_attr)
-			nla_strscpy(ifname, ifname_attr, IFNAMSIZ);
-		else if (altifname_attr)
-			nla_strscpy(ifname, altifname_attr, ALTIFNAMSIZ);
-		else
-			return NULL;
-	}
+				       struct nlattr *tb[])
+{
+	char ifname[ALTIFNAMSIZ];
+
+	if (tb[IFLA_IFNAME])
+		nla_strscpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);
+	else if (tb[IFLA_ALT_IFNAME])
+		nla_strscpy(ifname, tb[IFLA_ALT_IFNAME], ALTIFNAMSIZ);
+	else
+		return NULL;
 
 	return __dev_get_by_name(net, ifname);
 }
@@ -3000,7 +3001,6 @@  static int rtnl_setlink(struct sk_buff *skb, struct nlmsghdr *nlh,
 	struct net_device *dev;
 	int err;
 	struct nlattr *tb[IFLA_MAX+1];
-	char ifname[IFNAMSIZ];
 
 	err = nlmsg_parse_deprecated(nlh, sizeof(*ifm), tb, IFLA_MAX,
 				     ifla_policy, extack);
@@ -3011,17 +3011,12 @@  static int rtnl_setlink(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (err < 0)
 		goto errout;
 
-	if (tb[IFLA_IFNAME])
-		nla_strscpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);
-	else
-		ifname[0] = '\0';
-
 	err = -EINVAL;
 	ifm = nlmsg_data(nlh);
 	if (ifm->ifi_index > 0)
 		dev = __dev_get_by_index(net, ifm->ifi_index);
 	else if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME])
-		dev = rtnl_dev_get(net, NULL, tb[IFLA_ALT_IFNAME], ifname);
+		dev = rtnl_dev_get(net, tb);
 	else
 		goto errout;
 
@@ -3030,7 +3025,7 @@  static int rtnl_setlink(struct sk_buff *skb, struct nlmsghdr *nlh,
 		goto errout;
 	}
 
-	err = do_setlink(skb, dev, ifm, extack, tb, ifname, 0);
+	err = do_setlink(skb, dev, ifm, extack, tb, 0);
 errout:
 	return err;
 }
@@ -3119,8 +3114,7 @@  static int rtnl_dellink(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (ifm->ifi_index > 0)
 		dev = __dev_get_by_index(tgt_net, ifm->ifi_index);
 	else if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME])
-		dev = rtnl_dev_get(net, tb[IFLA_IFNAME],
-				   tb[IFLA_ALT_IFNAME], NULL);
+		dev = rtnl_dev_get(net, tb);
 	else if (tb[IFLA_GROUP])
 		err = rtnl_group_dellink(tgt_net, nla_get_u32(tb[IFLA_GROUP]));
 	else
@@ -3262,7 +3256,7 @@  static int rtnl_group_changelink(const struct sk_buff *skb,
 
 	for_each_netdev_safe(net, dev, aux) {
 		if (dev->group == group) {
-			err = do_setlink(skb, dev, ifm, extack, tb, NULL, 0);
+			err = do_setlink(skb, dev, ifm, extack, tb, 0);
 			if (err < 0)
 				return err;
 		}
@@ -3303,16 +3297,11 @@  static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (err < 0)
 		return err;
 
-	if (tb[IFLA_IFNAME])
-		nla_strscpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);
-	else
-		ifname[0] = '\0';
-
 	ifm = nlmsg_data(nlh);
 	if (ifm->ifi_index > 0)
 		dev = __dev_get_by_index(net, ifm->ifi_index);
 	else if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME])
-		dev = rtnl_dev_get(net, NULL, tb[IFLA_ALT_IFNAME], ifname);
+		dev = rtnl_dev_get(net, tb);
 	else
 		dev = NULL;
 
@@ -3413,7 +3402,7 @@  static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
 			status |= DO_SETLINK_NOTIFY;
 		}
 
-		return do_setlink(skb, dev, ifm, extack, tb, ifname, status);
+		return do_setlink(skb, dev, ifm, extack, tb, status);
 	}
 
 	if (!(nlh->nlmsg_flags & NLM_F_CREATE)) {
@@ -3445,7 +3434,9 @@  static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (!ops->alloc && !ops->setup)
 		return -EOPNOTSUPP;
 
-	if (!ifname[0]) {
+	if (tb[IFLA_IFNAME]) {
+		nla_strscpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);
+	} else {
 		snprintf(ifname, IFNAMSIZ, "%s%%d", ops->kind);
 		name_assign_type = NET_NAME_ENUM;
 	}
@@ -3617,8 +3608,7 @@  static int rtnl_getlink(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (ifm->ifi_index > 0)
 		dev = __dev_get_by_index(tgt_net, ifm->ifi_index);
 	else if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME])
-		dev = rtnl_dev_get(tgt_net, tb[IFLA_IFNAME],
-				   tb[IFLA_ALT_IFNAME], NULL);
+		dev = rtnl_dev_get(tgt_net, tb);
 	else
 		goto out;
 
@@ -3713,8 +3703,7 @@  static int rtnl_linkprop(int cmd, struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (ifm->ifi_index > 0)
 		dev = __dev_get_by_index(net, ifm->ifi_index);
 	else if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME])
-		dev = rtnl_dev_get(net, tb[IFLA_IFNAME],
-				   tb[IFLA_ALT_IFNAME], NULL);
+		dev = rtnl_dev_get(net, tb);
 	else
 		return -EINVAL;