Allow interface aliases to be used as regular interfaces.
Such that a command sequence like this one works:
$ ip l set eth0 alias internet
$ ip a s internet
$ tcpdump -n -i internet
Signed-off-by: Richard Weinberger <richard@xxxxxx>
---
include/linux/netdevice.h | 1 +
include/net/net_namespace.h | 1 +
net/core/dev.c | 52 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 54 insertions(+)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 679e6e9..e00b4e2 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1493,6 +1493,7 @@ struct net_device {
char name[IFNAMSIZ];
struct hlist_node name_hlist;
char *ifalias;
+ struct hlist_node ifalias_hlist;
/*
* I/O specific fields
* FIXME: Merge these and struct ifmap into one
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 2e8756b8..9fa0939 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -76,6 +76,7 @@ struct net {
struct list_head dev_base_head;
struct hlist_head *dev_name_head;
struct hlist_head *dev_index_head;
+ struct hlist_head *dev_ifalias_head;
unsigned int dev_base_seq; /* protected by rtnl_mutex */
int ifindex;
unsigned int dev_unreg_count;
diff --git a/net/core/dev.c b/net/core/dev.c
index 683d493..2551b03 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -202,6 +202,14 @@ static inline struct hlist_head *dev_index_hash(struct net *net, int ifindex)
return &net->dev_index_head[ifindex & (NETDEV_HASHENTRIES - 1)];
}
+static inline struct hlist_head *dev_ifalias_hash(struct net *net,
+ const char *ifalias)
+{
+ unsigned int hash = full_name_hash(ifalias, strnlen(ifalias, IFALIASZ));
+
+ return &net->dev_ifalias_head[hash_32(hash, NETDEV_HASHBITS)];
+}
+
static inline void rps_lock(struct softnet_data *sd)
{
#ifdef CONFIG_RPS
@@ -228,6 +236,9 @@ static void list_netdevice(struct net_device *dev)
hlist_add_head_rcu(&dev->name_hlist, dev_name_hash(net, dev->name));
hlist_add_head_rcu(&dev->index_hlist,
dev_index_hash(net, dev->ifindex));
+ if (dev->ifalias)
+ hlist_add_head_rcu(&dev->ifalias_hlist,
+ dev_ifalias_hash(net, dev->ifalias));
write_unlock_bh(&dev_base_lock);
dev_base_seq_inc(net);
@@ -245,6 +256,8 @@ static void unlist_netdevice(struct net_device *dev)
list_del_rcu(&dev->dev_list);
hlist_del_rcu(&dev->name_hlist);
hlist_del_rcu(&dev->index_hlist);
+ if (dev->ifalias)
+ hlist_del_rcu(&dev->ifalias_hlist);
write_unlock_bh(&dev_base_lock);
dev_base_seq_inc(dev_net(dev));
@@ -679,6 +692,11 @@ struct net_device *__dev_get_by_name(struct net *net, const char *name)
if (!strncmp(dev->name, name, IFNAMSIZ))
return dev;
+ head = dev_ifalias_hash(net, name);
+ hlist_for_each_entry(dev, head, ifalias_hlist)
+ if (dev->ifalias && !strncmp(dev->ifalias, name, IFALIASZ))
+ return dev;
+
return NULL;
}
EXPORT_SYMBOL(__dev_get_by_name);
@@ -704,6 +722,11 @@ struct net_device *dev_get_by_name_rcu(struct net *net, const char *name)
if (!strncmp(dev->name, name, IFNAMSIZ))
return dev;
+ head = dev_ifalias_hash(net, name);
+ hlist_for_each_entry_rcu(dev, head, ifalias_hlist)
+ if (dev->ifalias && !strncmp(dev->ifalias, name, IFALIASZ))
+ return dev;
+
return NULL;
}
EXPORT_SYMBOL(dev_get_by_name_rcu);
@@ -1169,6 +1192,20 @@ rollback:
return err;
}
+static void __hlist_del_alias(struct net_device *dev)
+{
+ write_lock_bh(&dev_base_lock);
+ hlist_del_rcu(&dev->ifalias_hlist);
+ write_unlock_bh(&dev_base_lock);
+}
+
+static void __hlist_add_alias(struct net_device *dev)
+{
+ write_lock_bh(&dev_base_lock);
+ hlist_add_head_rcu(&dev->ifalias_hlist, dev_ifalias_hash(dev_net(dev), dev->ifalias));
+ write_unlock_bh(&dev_base_lock);
+}
+
/**
* dev_set_alias - change ifalias of a device
* @dev: device
@@ -1189,15 +1226,24 @@ int dev_set_alias(struct net_device *dev, const char *alias, size_t len)
if (!len) {
kfree(dev->ifalias);
dev->ifalias = NULL;
+ __hlist_del_alias(dev);
return 0;
}
new_ifalias = krealloc(dev->ifalias, len + 1, GFP_KERNEL);
if (!new_ifalias)
return -ENOMEM;
+
+ if (dev->ifalias) {
+ __hlist_del_alias(dev);
+ synchronize_rcu();
+ }
+
dev->ifalias = new_ifalias;
strlcpy(dev->ifalias, alias, len+1);
+ __hlist_add_alias(dev);
+
return len;
}
@@ -7150,8 +7196,14 @@ static int __net_init netdev_init(struct net *net)
if (net->dev_index_head == NULL)
goto err_idx;
+ net->dev_ifalias_head = netdev_create_hash();
+ if (net->dev_ifalias_head == NULL)
+ goto err_alias;
+
return 0;
+err_alias:
+ kfree(net->dev_index_head);
err_idx:
kfree(net->dev_name_head);
err_name:
--
1.8.4.5
--
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