From 38e01b30563a5b5ade7b54e5d739d16a2b02fe82 Mon Sep 17 00:00:00 2001 From: Nicolas Dichtel Date: Thu, 25 Jan 2018 15:01:39 +0100 Subject: [PATCH] dev: advertise the new ifindex when the netns iface changes The goal is to let the user follow an interface that moves to another netns. CC: Jiri Benc CC: Christian Brauner Signed-off-by: Nicolas Dichtel Reviewed-by: Jiri Benc Signed-off-by: David S. Miller --- include/linux/rtnetlink.h | 5 +++-- include/uapi/linux/if_link.h | 1 + net/core/dev.c | 19 ++++++++++++------- net/core/rtnetlink.c | 31 ++++++++++++++++++++----------- 4 files changed, 36 insertions(+), 20 deletions(-) diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h index 62d508b..0514cc3 100644 --- a/include/linux/rtnetlink.h +++ b/include/linux/rtnetlink.h @@ -19,10 +19,11 @@ extern int rtnl_put_cacheinfo(struct sk_buff *skb, struct dst_entry *dst, void rtmsg_ifinfo(int type, struct net_device *dev, unsigned change, gfp_t flags); void rtmsg_ifinfo_newnet(int type, struct net_device *dev, unsigned int change, - gfp_t flags, int *new_nsid); + gfp_t flags, int *new_nsid, int new_ifindex); struct sk_buff *rtmsg_ifinfo_build_skb(int type, struct net_device *dev, unsigned change, u32 event, - gfp_t flags, int *new_nsid); + gfp_t flags, int *new_nsid, + int new_ifindex); void rtmsg_ifinfo_send(struct sk_buff *skb, struct net_device *dev, gfp_t flags); diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h index 8616131..6d94477 100644 --- a/include/uapi/linux/if_link.h +++ b/include/uapi/linux/if_link.h @@ -163,6 +163,7 @@ enum { IFLA_IF_NETNSID, IFLA_CARRIER_UP_COUNT, IFLA_CARRIER_DOWN_COUNT, + IFLA_NEW_IFINDEX, __IFLA_MAX }; diff --git a/net/core/dev.c b/net/core/dev.c index 59987eb..858501b 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -7360,7 +7360,7 @@ static void rollback_registered_many(struct list_head *head) if (!dev->rtnl_link_ops || dev->rtnl_link_state == RTNL_LINK_INITIALIZED) skb = rtmsg_ifinfo_build_skb(RTM_DELLINK, dev, ~0U, 0, - GFP_KERNEL, NULL); + GFP_KERNEL, NULL, 0); /* * Flush the unicast and multicast chains @@ -8473,7 +8473,7 @@ EXPORT_SYMBOL(unregister_netdev); int dev_change_net_namespace(struct net_device *dev, struct net *net, const char *pat) { - int err, new_nsid; + int err, new_nsid, new_ifindex; ASSERT_RTNL(); @@ -8529,8 +8529,16 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char call_netdevice_notifiers(NETDEV_UNREGISTER, dev); rcu_barrier(); call_netdevice_notifiers(NETDEV_UNREGISTER_FINAL, dev); + new_nsid = peernet2id_alloc(dev_net(dev), net); - rtmsg_ifinfo_newnet(RTM_DELLINK, dev, ~0U, GFP_KERNEL, &new_nsid); + /* If there is an ifindex conflict assign a new one */ + if (__dev_get_by_index(net, dev->ifindex)) + new_ifindex = dev_new_index(net); + else + new_ifindex = dev->ifindex; + + rtmsg_ifinfo_newnet(RTM_DELLINK, dev, ~0U, GFP_KERNEL, &new_nsid, + new_ifindex); /* * Flush the unicast and multicast chains @@ -8544,10 +8552,7 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char /* Actually switch the network namespace */ dev_net_set(dev, net); - - /* If there is an ifindex conflict assign a new one */ - if (__dev_get_by_index(net, dev->ifindex)) - dev->ifindex = dev_new_index(net); + dev->ifindex = new_ifindex; /* Send a netdev-add uevent to the new namespace */ kobject_uevent(&dev->dev.kobj, KOBJ_ADD); diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index f111557..e04af7b 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -988,6 +988,7 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev, + rtnl_xdp_size() /* IFLA_XDP */ + nla_total_size(4) /* IFLA_EVENT */ + nla_total_size(4) /* IFLA_NEW_NETNSID */ + + nla_total_size(4) /* IFLA_NEW_IFINDEX */ + nla_total_size(1) /* IFLA_PROTO_DOWN */ + nla_total_size(4) /* IFLA_IF_NETNSID */ + nla_total_size(4) /* IFLA_CARRIER_UP_COUNT */ @@ -1511,7 +1512,8 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev, struct net *src_net, int type, u32 pid, u32 seq, u32 change, unsigned int flags, u32 ext_filter_mask, - u32 event, int *new_nsid, int tgt_netnsid) + u32 event, int *new_nsid, int new_ifindex, + int tgt_netnsid) { struct ifinfomsg *ifm; struct nlmsghdr *nlh; @@ -1608,6 +1610,10 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, if (new_nsid && nla_put_s32(skb, IFLA_NEW_NETNSID, *new_nsid) < 0) goto nla_put_failure; + if (new_ifindex && + nla_put_s32(skb, IFLA_NEW_IFINDEX, new_ifindex) < 0) + goto nla_put_failure; + rcu_read_lock(); if (rtnl_fill_link_af(skb, dev, ext_filter_mask)) @@ -1853,7 +1859,7 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb) NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq, 0, flags, - ext_filter_mask, 0, NULL, + ext_filter_mask, 0, NULL, 0, netnsid); if (err < 0) { @@ -3088,7 +3094,7 @@ static int rtnl_getlink(struct sk_buff *skb, struct nlmsghdr *nlh, err = rtnl_fill_ifinfo(nskb, dev, net, RTM_NEWLINK, NETLINK_CB(skb).portid, nlh->nlmsg_seq, 0, 0, ext_filter_mask, - 0, NULL, netnsid); + 0, NULL, 0, netnsid); if (err < 0) { /* -EMSGSIZE implies BUG in if_nlmsg_size */ WARN_ON(err == -EMSGSIZE); @@ -3184,7 +3190,8 @@ static int rtnl_dump_all(struct sk_buff *skb, struct netlink_callback *cb) struct sk_buff *rtmsg_ifinfo_build_skb(int type, struct net_device *dev, unsigned int change, - u32 event, gfp_t flags, int *new_nsid) + u32 event, gfp_t flags, int *new_nsid, + int new_ifindex) { struct net *net = dev_net(dev); struct sk_buff *skb; @@ -3197,7 +3204,7 @@ struct sk_buff *rtmsg_ifinfo_build_skb(int type, struct net_device *dev, err = rtnl_fill_ifinfo(skb, dev, dev_net(dev), type, 0, 0, change, 0, 0, event, - new_nsid, -1); + new_nsid, new_ifindex, -1); if (err < 0) { /* -EMSGSIZE implies BUG in if_nlmsg_size() */ WARN_ON(err == -EMSGSIZE); @@ -3220,14 +3227,15 @@ void rtmsg_ifinfo_send(struct sk_buff *skb, struct net_device *dev, gfp_t flags) static void rtmsg_ifinfo_event(int type, struct net_device *dev, unsigned int change, u32 event, - gfp_t flags, int *new_nsid) + gfp_t flags, int *new_nsid, int new_ifindex) { struct sk_buff *skb; if (dev->reg_state != NETREG_REGISTERED) return; - skb = rtmsg_ifinfo_build_skb(type, dev, change, event, flags, new_nsid); + skb = rtmsg_ifinfo_build_skb(type, dev, change, event, flags, new_nsid, + new_ifindex); if (skb) rtmsg_ifinfo_send(skb, dev, flags); } @@ -3235,14 +3243,15 @@ static void rtmsg_ifinfo_event(int type, struct net_device *dev, void rtmsg_ifinfo(int type, struct net_device *dev, unsigned int change, gfp_t flags) { - rtmsg_ifinfo_event(type, dev, change, rtnl_get_event(0), flags, NULL); + rtmsg_ifinfo_event(type, dev, change, rtnl_get_event(0), flags, + NULL, 0); } void rtmsg_ifinfo_newnet(int type, struct net_device *dev, unsigned int change, - gfp_t flags, int *new_nsid) + gfp_t flags, int *new_nsid, int new_ifindex) { rtmsg_ifinfo_event(type, dev, change, rtnl_get_event(0), flags, - new_nsid); + new_nsid, new_ifindex); } static int nlmsg_populate_fdb_fill(struct sk_buff *skb, @@ -4642,7 +4651,7 @@ static int rtnetlink_event(struct notifier_block *this, unsigned long event, voi case NETDEV_CHANGELOWERSTATE: case NETDEV_CHANGE_TX_QUEUE_LEN: rtmsg_ifinfo_event(RTM_NEWLINK, dev, 0, rtnl_get_event(event), - GFP_KERNEL, NULL); + GFP_KERNEL, NULL, 0); break; default: break; -- 2.7.4