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Date: Thu, 8 Aug 2019 21:11:30 -0700
From: Roopa Prabhu <roopa@...ulusnetworks.com>
To: Jiri Pirko <jiri@...nulli.us>
Cc: netdev <netdev@...r.kernel.org>,
David Miller <davem@...emloft.net>,
Jakub Kicinski <jakub.kicinski@...ronome.com>,
Stephen Hemminger <sthemmin@...rosoft.com>,
David Ahern <dsahern@...il.com>, dcbw@...hat.com,
Michal Kubecek <mkubecek@...e.cz>,
Andrew Lunn <andrew@...n.ch>, parav@...lanox.com,
Saeed Mahameed <saeedm@...lanox.com>,
mlxsw <mlxsw@...lanox.com>
Subject: Re: [patch net-next rfc 3/7] net: rtnetlink: add commands to add and
delete alternative ifnames
On Fri, Jul 19, 2019 at 4:00 AM Jiri Pirko <jiri@...nulli.us> wrote:
>
> From: Jiri Pirko <jiri@...lanox.com>
>
> Add two commands to add and delete alternative ifnames for net device.
> Each net device can have multiple alternative names.
>
> Signed-off-by: Jiri Pirko <jiri@...lanox.com>
> ---
> include/linux/netdevice.h | 4 ++
> include/uapi/linux/if.h | 1 +
> include/uapi/linux/if_link.h | 1 +
> include/uapi/linux/rtnetlink.h | 7 +++
> net/core/dev.c | 58 ++++++++++++++++++-
> net/core/rtnetlink.c | 102 +++++++++++++++++++++++++++++++++
> security/selinux/nlmsgtab.c | 4 +-
> 7 files changed, 175 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index 74f99f127b0e..6922fdb483ca 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -920,10 +920,14 @@ struct tlsdev_ops;
>
> struct netdev_name_node {
> struct hlist_node hlist;
> + struct list_head list;
> struct net_device *dev;
> char *name;
> };
>
> +int netdev_name_node_alt_create(struct net_device *dev, char *name);
> +int netdev_name_node_alt_destroy(struct net_device *dev, char *name);
> +
> /*
> * This structure defines the management hooks for network devices.
> * The following hooks can be defined; unless noted otherwise, they are
> diff --git a/include/uapi/linux/if.h b/include/uapi/linux/if.h
> index 7fea0fd7d6f5..4bf33344aab1 100644
> --- a/include/uapi/linux/if.h
> +++ b/include/uapi/linux/if.h
> @@ -33,6 +33,7 @@
> #define IFNAMSIZ 16
> #endif /* __UAPI_DEF_IF_IFNAMSIZ */
> #define IFALIASZ 256
> +#define ALTIFNAMSIZ 128
> #include <linux/hdlc/ioctl.h>
>
> /* For glibc compatibility. An empty enum does not compile. */
> diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
> index 4a8c02cafa9a..92268946e04a 100644
> --- a/include/uapi/linux/if_link.h
> +++ b/include/uapi/linux/if_link.h
> @@ -167,6 +167,7 @@ enum {
> IFLA_NEW_IFINDEX,
> IFLA_MIN_MTU,
> IFLA_MAX_MTU,
> + IFLA_ALT_IFNAME_MOD, /* Alternative ifname to add/delete */
> __IFLA_MAX
> };
>
> diff --git a/include/uapi/linux/rtnetlink.h b/include/uapi/linux/rtnetlink.h
> index ce2a623abb75..b36cfd83eb76 100644
> --- a/include/uapi/linux/rtnetlink.h
> +++ b/include/uapi/linux/rtnetlink.h
> @@ -164,6 +164,13 @@ enum {
> RTM_GETNEXTHOP,
> #define RTM_GETNEXTHOP RTM_GETNEXTHOP
>
> + RTM_NEWALTIFNAME = 108,
> +#define RTM_NEWALTIFNAME RTM_NEWALTIFNAME
> + RTM_DELALTIFNAME,
> +#define RTM_DELALTIFNAME RTM_DELALTIFNAME
> + RTM_GETALTIFNAME,
> +#define RTM_GETALTIFNAME RTM_GETALTIFNAME
> +
I might have missed the prior discussion, why do we need new commands
?. can't this simply be part of RTM_*LINK and we use RTM_SETLINK to
set alternate names ?
> __RTM_MAX,
> #define RTM_MAX (((__RTM_MAX + 3) & ~3) - 1)
> };
> diff --git a/net/core/dev.c b/net/core/dev.c
> index ad0d42fbdeee..2a3be2b279d3 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -244,7 +244,13 @@ static struct netdev_name_node *netdev_name_node_alloc(struct net_device *dev,
> static struct netdev_name_node *
> netdev_name_node_head_alloc(struct net_device *dev)
> {
> - return netdev_name_node_alloc(dev, dev->name);
> + struct netdev_name_node *name_node;
> +
> + name_node = netdev_name_node_alloc(dev, dev->name);
> + if (!name_node)
> + return NULL;
> + INIT_LIST_HEAD(&name_node->list);
> + return name_node;
> }
>
> static void netdev_name_node_free(struct netdev_name_node *name_node)
> @@ -288,6 +294,55 @@ static struct netdev_name_node *netdev_name_node_lookup_rcu(struct net *net,
> return NULL;
> }
>
> +int netdev_name_node_alt_create(struct net_device *dev, char *name)
> +{
> + struct netdev_name_node *name_node;
> + struct net *net = dev_net(dev);
> +
> + name_node = netdev_name_node_lookup(net, name);
> + if (name_node)
> + return -EEXIST;
> + name_node = netdev_name_node_alloc(dev, name);
> + if (!name_node)
> + return -ENOMEM;
> + netdev_name_node_add(net, name_node);
> + /* The node that holds dev->name acts as a head of per-device list. */
> + list_add_tail(&name_node->list, &dev->name_node->list);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(netdev_name_node_alt_create);
> +
> +static void __netdev_name_node_alt_destroy(struct netdev_name_node *name_node)
> +{
> + list_del(&name_node->list);
> + netdev_name_node_del(name_node);
> + kfree(name_node->name);
> + netdev_name_node_free(name_node);
> +}
> +
> +int netdev_name_node_alt_destroy(struct net_device *dev, char *name)
> +{
> + struct netdev_name_node *name_node;
> + struct net *net = dev_net(dev);
> +
> + name_node = netdev_name_node_lookup(net, name);
> + if (!name_node)
> + return -ENOENT;
> + __netdev_name_node_alt_destroy(name_node);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(netdev_name_node_alt_destroy);
> +
> +static void netdev_name_node_alt_flush(struct net_device *dev)
> +{
> + struct netdev_name_node *name_node, *tmp;
> +
> + list_for_each_entry_safe(name_node, tmp, &dev->name_node->list, list)
> + __netdev_name_node_alt_destroy(name_node);
> +}
> +
> /* Device list insertion */
> static void list_netdevice(struct net_device *dev)
> {
> @@ -8258,6 +8313,7 @@ static void rollback_registered_many(struct list_head *head)
> dev_uc_flush(dev);
> dev_mc_flush(dev);
>
> + netdev_name_node_alt_flush(dev);
> netdev_name_node_free(dev->name_node);
>
> if (dev->netdev_ops->ndo_uninit)
> diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
> index 1ee6460f8275..7a2010b16e10 100644
> --- a/net/core/rtnetlink.c
> +++ b/net/core/rtnetlink.c
> @@ -1750,6 +1750,8 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
> [IFLA_CARRIER_DOWN_COUNT] = { .type = NLA_U32 },
> [IFLA_MIN_MTU] = { .type = NLA_U32 },
> [IFLA_MAX_MTU] = { .type = NLA_U32 },
> + [IFLA_ALT_IFNAME_MOD] = { .type = NLA_STRING,
> + .len = ALTIFNAMSIZ - 1 },
> };
>
> static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = {
> @@ -3373,6 +3375,103 @@ static int rtnl_getlink(struct sk_buff *skb, struct nlmsghdr *nlh,
> return err;
> }
>
> +static int rtnl_newaltifname(struct sk_buff *skb, struct nlmsghdr *nlh,
> + struct netlink_ext_ack *extack)
> +{
> + struct net *net = sock_net(skb->sk);
> + struct nlattr *tb[IFLA_MAX + 1];
> + struct net_device *dev;
> + struct ifinfomsg *ifm;
> + char *new_alt_ifname;
> + int err;
> +
> + err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFLA_MAX, ifla_policy, extack);
> + if (err)
> + return err;
> +
> + err = rtnl_ensure_unique_netns(tb, extack, true);
> + if (err)
> + return err;
> +
> + ifm = nlmsg_data(nlh);
> + if (ifm->ifi_index > 0) {
> + dev = __dev_get_by_index(net, ifm->ifi_index);
> + } else if (tb[IFLA_IFNAME]) {
> + char ifname[IFNAMSIZ];
> +
> + nla_strlcpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);
> + dev = __dev_get_by_name(net, ifname);
> + } else {
> + return -EINVAL;
> + }
> +
> + if (!dev)
> + return -ENODEV;
> +
> + if (!tb[IFLA_ALT_IFNAME_MOD])
> + return -EINVAL;
> +
> + new_alt_ifname = nla_strdup(tb[IFLA_ALT_IFNAME_MOD], GFP_KERNEL);
> + if (!new_alt_ifname)
> + return -ENOMEM;
> +
> + err = netdev_name_node_alt_create(dev, new_alt_ifname);
> + if (err)
> + goto out_free_new_alt_ifname;
> +
> + return 0;
> +
> +out_free_new_alt_ifname:
> + kfree(new_alt_ifname);
> + return err;
> +}
> +
> +static int rtnl_delaltifname(struct sk_buff *skb, struct nlmsghdr *nlh,
> + struct netlink_ext_ack *extack)
> +{
> + struct net *net = sock_net(skb->sk);
> + struct nlattr *tb[IFLA_MAX + 1];
> + struct net_device *dev;
> + struct ifinfomsg *ifm;
> + char *del_alt_ifname;
> + int err;
> +
> + err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFLA_MAX, ifla_policy, extack);
> + if (err)
> + return err;
> +
> + err = rtnl_ensure_unique_netns(tb, extack, true);
> + if (err)
> + return err;
> +
> + ifm = nlmsg_data(nlh);
> + if (ifm->ifi_index > 0) {
> + dev = __dev_get_by_index(net, ifm->ifi_index);
> + } else if (tb[IFLA_IFNAME]) {
> + char ifname[IFNAMSIZ];
> +
> + nla_strlcpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);
> + dev = __dev_get_by_name(net, ifname);
> + } else {
> + return -EINVAL;
> + }
> +
> + if (!dev)
> + return -ENODEV;
> +
> + if (!tb[IFLA_ALT_IFNAME_MOD])
> + return -EINVAL;
> +
> + del_alt_ifname = nla_strdup(tb[IFLA_ALT_IFNAME_MOD], GFP_KERNEL);
> + if (!del_alt_ifname)
> + return -ENOMEM;
> +
> + err = netdev_name_node_alt_destroy(dev, del_alt_ifname);
> + kfree(del_alt_ifname);
> +
> + return err;
> +}
> +
> static u16 rtnl_calcit(struct sk_buff *skb, struct nlmsghdr *nlh)
> {
> struct net *net = sock_net(skb->sk);
> @@ -5331,6 +5430,9 @@ void __init rtnetlink_init(void)
> rtnl_register(PF_UNSPEC, RTM_GETROUTE, NULL, rtnl_dump_all, 0);
> rtnl_register(PF_UNSPEC, RTM_GETNETCONF, NULL, rtnl_dump_all, 0);
>
> + rtnl_register(PF_UNSPEC, RTM_NEWALTIFNAME, rtnl_newaltifname, NULL, 0);
> + rtnl_register(PF_UNSPEC, RTM_DELALTIFNAME, rtnl_delaltifname, NULL, 0);
> +
> rtnl_register(PF_BRIDGE, RTM_NEWNEIGH, rtnl_fdb_add, NULL, 0);
> rtnl_register(PF_BRIDGE, RTM_DELNEIGH, rtnl_fdb_del, NULL, 0);
> rtnl_register(PF_BRIDGE, RTM_GETNEIGH, rtnl_fdb_get, rtnl_fdb_dump, 0);
> diff --git a/security/selinux/nlmsgtab.c b/security/selinux/nlmsgtab.c
> index 58345ba0528e..a712b54c666c 100644
> --- a/security/selinux/nlmsgtab.c
> +++ b/security/selinux/nlmsgtab.c
> @@ -83,6 +83,8 @@ static const struct nlmsg_perm nlmsg_route_perms[] =
> { RTM_NEWNEXTHOP, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
> { RTM_DELNEXTHOP, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
> { RTM_GETNEXTHOP, NETLINK_ROUTE_SOCKET__NLMSG_READ },
> + { RTM_NEWALTIFNAME, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
> + { RTM_DELALTIFNAME, NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
> };
>
> static const struct nlmsg_perm nlmsg_tcpdiag_perms[] =
> @@ -166,7 +168,7 @@ int selinux_nlmsg_lookup(u16 sclass, u16 nlmsg_type, u32 *perm)
> * structures at the top of this file with the new mappings
> * before updating the BUILD_BUG_ON() macro!
> */
> - BUILD_BUG_ON(RTM_MAX != (RTM_NEWNEXTHOP + 3));
> + BUILD_BUG_ON(RTM_MAX != (RTM_NEWALTIFNAME + 3));
> err = nlmsg_perm(nlmsg_type, perm, nlmsg_route_perms,
> sizeof(nlmsg_route_perms));
> break;
> --
> 2.21.0
>
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