net: vrf: Fix dst reference counting
Vivek reported a kernel exception deleting a VRF with an active connection through it. The root cause is that the socket has a cached reference to a dst that is destroyed. Converting the dst_destroy to dst_release and letting proper reference counting kick in does not work as the dst has a reference to the device which needs to be released as well. I talked to Hannes about this at netdev and he pointed out the ipv4 and ipv6 dst handling has dst_ifdown for just this scenario. Rather than continuing with the reinvented dst wheel in VRF just remove it and leverage the ipv4 and ipv6 versions. Fixes:193125dbd8("net: Introduce VRF device driver") Fixes:35402e3136("net: Add IPv6 support to VRF device") Signed-off-by: David Ahern <dsa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Ahern
David S. Miller
parent
10c3c02255
commit
9ab179d83b
5 changed files with 30 additions and 167 deletions
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@ -60,41 +60,6 @@ struct pcpu_dstats {
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struct u64_stats_sync syncp;
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};
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static struct dst_entry *vrf_ip_check(struct dst_entry *dst, u32 cookie)
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{
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return dst;
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}
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static int vrf_ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb)
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{
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return ip_local_out(net, sk, skb);
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}
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static unsigned int vrf_v4_mtu(const struct dst_entry *dst)
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{
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/* TO-DO: return max ethernet size? */
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return dst->dev->mtu;
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}
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static void vrf_dst_destroy(struct dst_entry *dst)
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{
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/* our dst lives forever - or until the device is closed */
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}
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static unsigned int vrf_default_advmss(const struct dst_entry *dst)
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{
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return 65535 - 40;
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}
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static struct dst_ops vrf_dst_ops = {
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.family = AF_INET,
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.local_out = vrf_ip_local_out,
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.check = vrf_ip_check,
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.mtu = vrf_v4_mtu,
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.destroy = vrf_dst_destroy,
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.default_advmss = vrf_default_advmss,
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};
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/* neighbor handling is done with actual device; do not want
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* to flip skb->dev for those ndisc packets. This really fails
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* for multiple next protocols (e.g., NEXTHDR_HOP). But it is
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@ -349,46 +314,6 @@ static netdev_tx_t vrf_xmit(struct sk_buff *skb, struct net_device *dev)
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}
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#if IS_ENABLED(CONFIG_IPV6)
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static struct dst_entry *vrf_ip6_check(struct dst_entry *dst, u32 cookie)
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{
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return dst;
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}
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static struct dst_ops vrf_dst_ops6 = {
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.family = AF_INET6,
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.local_out = ip6_local_out,
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.check = vrf_ip6_check,
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.mtu = vrf_v4_mtu,
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.destroy = vrf_dst_destroy,
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.default_advmss = vrf_default_advmss,
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};
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static int init_dst_ops6_kmem_cachep(void)
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{
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vrf_dst_ops6.kmem_cachep = kmem_cache_create("vrf_ip6_dst_cache",
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sizeof(struct rt6_info),
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0,
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SLAB_HWCACHE_ALIGN,
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NULL);
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if (!vrf_dst_ops6.kmem_cachep)
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return -ENOMEM;
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return 0;
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}
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static void free_dst_ops6_kmem_cachep(void)
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{
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kmem_cache_destroy(vrf_dst_ops6.kmem_cachep);
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}
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static int vrf_input6(struct sk_buff *skb)
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{
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skb->dev->stats.rx_errors++;
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kfree_skb(skb);
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return 0;
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}
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/* modelled after ip6_finish_output2 */
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static int vrf_finish_output6(struct net *net, struct sock *sk,
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struct sk_buff *skb)
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@ -429,67 +354,34 @@ static int vrf_output6(struct net *net, struct sock *sk, struct sk_buff *skb)
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!(IP6CB(skb)->flags & IP6SKB_REROUTED));
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}
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static void vrf_rt6_destroy(struct net_vrf *vrf)
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static void vrf_rt6_release(struct net_vrf *vrf)
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{
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dst_destroy(&vrf->rt6->dst);
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free_percpu(vrf->rt6->rt6i_pcpu);
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dst_release(&vrf->rt6->dst);
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vrf->rt6 = NULL;
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}
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static int vrf_rt6_create(struct net_device *dev)
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{
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struct net_vrf *vrf = netdev_priv(dev);
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struct dst_entry *dst;
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struct net *net = dev_net(dev);
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struct rt6_info *rt6;
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int cpu;
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int rc = -ENOMEM;
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rt6 = dst_alloc(&vrf_dst_ops6, dev, 0,
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DST_OBSOLETE_NONE,
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(DST_HOST | DST_NOPOLICY | DST_NOXFRM));
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rt6 = ip6_dst_alloc(net, dev,
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DST_HOST | DST_NOPOLICY | DST_NOXFRM | DST_NOCACHE);
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if (!rt6)
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goto out;
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dst = &rt6->dst;
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rt6->rt6i_pcpu = alloc_percpu_gfp(struct rt6_info *, GFP_KERNEL);
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if (!rt6->rt6i_pcpu) {
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dst_destroy(dst);
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goto out;
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}
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for_each_possible_cpu(cpu) {
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struct rt6_info **p = per_cpu_ptr(rt6->rt6i_pcpu, cpu);
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*p = NULL;
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}
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memset(dst + 1, 0, sizeof(*rt6) - sizeof(*dst));
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INIT_LIST_HEAD(&rt6->rt6i_siblings);
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INIT_LIST_HEAD(&rt6->rt6i_uncached);
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rt6->dst.input = vrf_input6;
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rt6->dst.output = vrf_output6;
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rt6->rt6i_table = fib6_get_table(dev_net(dev), vrf->tb_id);
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atomic_set(&rt6->dst.__refcnt, 2);
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rt6->rt6i_table = fib6_get_table(net, vrf->tb_id);
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dst_hold(&rt6->dst);
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vrf->rt6 = rt6;
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rc = 0;
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out:
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return rc;
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}
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#else
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static int init_dst_ops6_kmem_cachep(void)
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{
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return 0;
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}
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static void free_dst_ops6_kmem_cachep(void)
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{
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}
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static void vrf_rt6_destroy(struct net_vrf *vrf)
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static void vrf_rt6_release(struct net_vrf *vrf)
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{
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}
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@ -557,11 +449,11 @@ static int vrf_output(struct net *net, struct sock *sk, struct sk_buff *skb)
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!(IPCB(skb)->flags & IPSKB_REROUTED));
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}
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static void vrf_rtable_destroy(struct net_vrf *vrf)
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static void vrf_rtable_release(struct net_vrf *vrf)
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{
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struct dst_entry *dst = (struct dst_entry *)vrf->rth;
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dst_destroy(dst);
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dst_release(dst);
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vrf->rth = NULL;
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}
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@ -570,22 +462,10 @@ static struct rtable *vrf_rtable_create(struct net_device *dev)
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struct net_vrf *vrf = netdev_priv(dev);
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struct rtable *rth;
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rth = dst_alloc(&vrf_dst_ops, dev, 2,
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DST_OBSOLETE_NONE,
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(DST_HOST | DST_NOPOLICY | DST_NOXFRM));
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rth = rt_dst_alloc(dev, 0, RTN_UNICAST, 1, 1, 0);
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if (rth) {
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rth->dst.output = vrf_output;
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rth->rt_genid = rt_genid_ipv4(dev_net(dev));
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rth->rt_flags = 0;
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rth->rt_type = RTN_UNICAST;
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rth->rt_is_input = 0;
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rth->rt_iif = 0;
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rth->rt_pmtu = 0;
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rth->rt_gateway = 0;
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rth->rt_uses_gateway = 0;
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rth->rt_table_id = vrf->tb_id;
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INIT_LIST_HEAD(&rth->rt_uncached);
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rth->rt_uncached_list = NULL;
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}
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return rth;
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@ -673,8 +553,8 @@ static void vrf_dev_uninit(struct net_device *dev)
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struct net_device *port_dev;
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struct list_head *iter;
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vrf_rtable_destroy(vrf);
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vrf_rt6_destroy(vrf);
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vrf_rtable_release(vrf);
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vrf_rt6_release(vrf);
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netdev_for_each_lower_dev(dev, port_dev, iter)
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vrf_del_slave(dev, port_dev);
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@ -704,7 +584,7 @@ static int vrf_dev_init(struct net_device *dev)
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return 0;
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out_rth:
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vrf_rtable_destroy(vrf);
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vrf_rtable_release(vrf);
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out_stats:
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free_percpu(dev->dstats);
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dev->dstats = NULL;
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@ -737,7 +617,7 @@ static struct rtable *vrf_get_rtable(const struct net_device *dev,
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struct net_vrf *vrf = netdev_priv(dev);
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rth = vrf->rth;
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atomic_inc(&rth->dst.__refcnt);
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dst_hold(&rth->dst);
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}
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return rth;
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@ -788,7 +668,7 @@ static struct dst_entry *vrf_get_rt6_dst(const struct net_device *dev,
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struct net_vrf *vrf = netdev_priv(dev);
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rt = vrf->rt6;
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atomic_inc(&rt->dst.__refcnt);
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dst_hold(&rt->dst);
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}
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return (struct dst_entry *)rt;
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@ -946,19 +826,6 @@ static int __init vrf_init_module(void)
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{
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int rc;
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vrf_dst_ops.kmem_cachep =
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kmem_cache_create("vrf_ip_dst_cache",
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sizeof(struct rtable), 0,
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SLAB_HWCACHE_ALIGN,
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NULL);
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if (!vrf_dst_ops.kmem_cachep)
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return -ENOMEM;
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rc = init_dst_ops6_kmem_cachep();
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if (rc != 0)
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goto error2;
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register_netdevice_notifier(&vrf_notifier_block);
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rc = rtnl_link_register(&vrf_link_ops);
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@ -969,22 +836,10 @@ static int __init vrf_init_module(void)
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error:
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unregister_netdevice_notifier(&vrf_notifier_block);
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free_dst_ops6_kmem_cachep();
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error2:
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kmem_cache_destroy(vrf_dst_ops.kmem_cachep);
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return rc;
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}
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static void __exit vrf_cleanup_module(void)
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{
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rtnl_link_unregister(&vrf_link_ops);
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unregister_netdevice_notifier(&vrf_notifier_block);
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kmem_cache_destroy(vrf_dst_ops.kmem_cachep);
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free_dst_ops6_kmem_cachep();
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}
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module_init(vrf_init_module);
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module_exit(vrf_cleanup_module);
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MODULE_AUTHOR("Shrijeet Mukherjee, David Ahern");
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MODULE_DESCRIPTION("Device driver to instantiate VRF domains");
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MODULE_LICENSE("GPL");
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@ -101,6 +101,9 @@ void fib6_force_start_gc(struct net *net);
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struct rt6_info *addrconf_dst_alloc(struct inet6_dev *idev,
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const struct in6_addr *addr, bool anycast);
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struct rt6_info *ip6_dst_alloc(struct net *net, struct net_device *dev,
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int flags);
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/*
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* support functions for ND
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*
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@ -209,6 +209,9 @@ unsigned int inet_addr_type_dev_table(struct net *net,
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void ip_rt_multicast_event(struct in_device *);
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int ip_rt_ioctl(struct net *, unsigned int cmd, void __user *arg);
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void ip_rt_get_source(u8 *src, struct sk_buff *skb, struct rtable *rt);
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struct rtable *rt_dst_alloc(struct net_device *dev,
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unsigned int flags, u16 type,
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bool nopolicy, bool noxfrm, bool will_cache);
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struct in_ifaddr;
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void fib_add_ifaddr(struct in_ifaddr *);
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@ -1438,9 +1438,9 @@ static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
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#endif
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}
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static struct rtable *rt_dst_alloc(struct net_device *dev,
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unsigned int flags, u16 type,
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bool nopolicy, bool noxfrm, bool will_cache)
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struct rtable *rt_dst_alloc(struct net_device *dev,
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unsigned int flags, u16 type,
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bool nopolicy, bool noxfrm, bool will_cache)
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{
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struct rtable *rt;
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@ -1468,6 +1468,7 @@ static struct rtable *rt_dst_alloc(struct net_device *dev,
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return rt;
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}
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EXPORT_SYMBOL(rt_dst_alloc);
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/* called in rcu_read_lock() section */
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static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
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@ -338,9 +338,9 @@ static struct rt6_info *__ip6_dst_alloc(struct net *net,
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return rt;
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}
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static struct rt6_info *ip6_dst_alloc(struct net *net,
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struct net_device *dev,
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int flags)
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struct rt6_info *ip6_dst_alloc(struct net *net,
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struct net_device *dev,
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int flags)
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{
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struct rt6_info *rt = __ip6_dst_alloc(net, dev, flags);
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@ -364,6 +364,7 @@ static struct rt6_info *ip6_dst_alloc(struct net *net,
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return rt;
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}
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EXPORT_SYMBOL(ip6_dst_alloc);
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static void ip6_dst_destroy(struct dst_entry *dst)
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{
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