lkml.org 
[lkml]   [2018]   [Feb]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.4 002/193] net: replace dst_cache ip6_tunnel implementation with the generic one
    Date
    4.4-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Paolo Abeni <pabeni@redhat.com>

    commit 607f725f6f7d5ec3759fbc16224afb60e2152a5b upstream.

    This also fix a potential race into the existing tunnel code, which
    could lead to the wrong dst to be permanenty cached:

    CPU1: CPU2:
    <xmit on ip6_tunnel>
    <cache lookup fails>
    dst = ip6_route_output(...)
    <tunnel params are changed via nl>
    dst_cache_reset() // no effect,
    // the cache is empty
    dst_cache_set() // the wrong dst
    // is permanenty stored
    // into the cache

    With the new dst implementation the above race is not possible
    since the first cache lookup after dst_cache_reset will fail due
    to the timestamp check

    Signed-off-by: Paolo Abeni <pabeni@redhat.com>
    Suggested-and-acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    Signed-off-by: Manoj Boopathi Raj <manojboopathi@google.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    include/net/ip6_tunnel.h | 15 ----
    net/ipv6/Kconfig | 1
    net/ipv6/ip6_gre.c | 12 +--
    net/ipv6/ip6_tunnel.c | 151 +++++++----------------------------------------
    net/ipv6/ip6_vti.c | 2
    5 files changed, 35 insertions(+), 146 deletions(-)

    --- a/include/net/ip6_tunnel.h
    +++ b/include/net/ip6_tunnel.h
    @@ -5,6 +5,8 @@
    #include <linux/netdevice.h>
    #include <linux/if_tunnel.h>
    #include <linux/ip6_tunnel.h>
    +#include <net/ip_tunnels.h>
    +#include <net/dst_cache.h>

    #define IP6TUNNEL_ERR_TIMEO (30*HZ)

    @@ -32,12 +34,6 @@ struct __ip6_tnl_parm {
    __be32 o_key;
    };

    -struct ip6_tnl_dst {
    - seqlock_t lock;
    - struct dst_entry __rcu *dst;
    - u32 cookie;
    -};
    -
    /* IPv6 tunnel */
    struct ip6_tnl {
    struct ip6_tnl __rcu *next; /* next tunnel in list */
    @@ -45,7 +41,7 @@ struct ip6_tnl {
    struct net *net; /* netns for packet i/o */
    struct __ip6_tnl_parm parms; /* tunnel configuration parameters */
    struct flowi fl; /* flowi template for xmit */
    - struct ip6_tnl_dst __percpu *dst_cache; /* cached dst */
    + struct dst_cache dst_cache; /* cached dst */

    int err_count;
    unsigned long err_time;
    @@ -65,11 +61,6 @@ struct ipv6_tlv_tnl_enc_lim {
    __u8 encap_limit; /* tunnel encapsulation limit */
    } __packed;

    -struct dst_entry *ip6_tnl_dst_get(struct ip6_tnl *t);
    -int ip6_tnl_dst_init(struct ip6_tnl *t);
    -void ip6_tnl_dst_destroy(struct ip6_tnl *t);
    -void ip6_tnl_dst_reset(struct ip6_tnl *t);
    -void ip6_tnl_dst_set(struct ip6_tnl *t, struct dst_entry *dst);
    int ip6_tnl_rcv_ctl(struct ip6_tnl *t, const struct in6_addr *laddr,
    const struct in6_addr *raddr);
    int ip6_tnl_xmit_ctl(struct ip6_tnl *t, const struct in6_addr *laddr,
    --- a/net/ipv6/Kconfig
    +++ b/net/ipv6/Kconfig
    @@ -205,6 +205,7 @@ config IPV6_NDISC_NODETYPE
    config IPV6_TUNNEL
    tristate "IPv6: IP-in-IPv6 tunnel (RFC2473)"
    select INET6_TUNNEL
    + select DST_CACHE
    ---help---
    Support for IPv6-in-IPv6 and IPv4-in-IPv6 tunnels described in
    RFC 2473.
    --- a/net/ipv6/ip6_gre.c
    +++ b/net/ipv6/ip6_gre.c
    @@ -362,7 +362,7 @@ static void ip6gre_tunnel_uninit(struct
    struct ip6gre_net *ign = net_generic(t->net, ip6gre_net_id);

    ip6gre_tunnel_unlink(ign, t);
    - ip6_tnl_dst_reset(t);
    + dst_cache_reset(&t->dst_cache);
    dev_put(dev);
    }

    @@ -640,7 +640,7 @@ static netdev_tx_t ip6gre_xmit2(struct s
    }

    if (!fl6->flowi6_mark)
    - dst = ip6_tnl_dst_get(tunnel);
    + dst = dst_cache_get(&tunnel->dst_cache);

    if (!dst) {
    dst = ip6_route_output(net, NULL, fl6);
    @@ -709,7 +709,7 @@ static netdev_tx_t ip6gre_xmit2(struct s
    }

    if (!fl6->flowi6_mark && ndst)
    - ip6_tnl_dst_set(tunnel, ndst);
    + dst_cache_set_ip6(&tunnel->dst_cache, ndst, &fl6->saddr);
    skb_dst_set(skb, dst);

    proto = NEXTHDR_GRE;
    @@ -1017,7 +1017,7 @@ static int ip6gre_tnl_change(struct ip6_
    t->parms.o_key = p->o_key;
    t->parms.i_flags = p->i_flags;
    t->parms.o_flags = p->o_flags;
    - ip6_tnl_dst_reset(t);
    + dst_cache_reset(&t->dst_cache);
    ip6gre_tnl_link_config(t, set_mtu);
    return 0;
    }
    @@ -1228,7 +1228,7 @@ static void ip6gre_dev_free(struct net_d
    {
    struct ip6_tnl *t = netdev_priv(dev);

    - ip6_tnl_dst_destroy(t);
    + dst_cache_destroy(&t->dst_cache);
    free_percpu(dev->tstats);
    free_netdev(dev);
    }
    @@ -1266,7 +1266,7 @@ static int ip6gre_tunnel_init_common(str
    if (!dev->tstats)
    return -ENOMEM;

    - ret = ip6_tnl_dst_init(tunnel);
    + ret = dst_cache_init(&tunnel->dst_cache, GFP_KERNEL);
    if (ret) {
    free_percpu(dev->tstats);
    dev->tstats = NULL;
    --- a/net/ipv6/ip6_tunnel.c
    +++ b/net/ipv6/ip6_tunnel.c
    @@ -122,97 +122,6 @@ static struct net_device_stats *ip6_get_
    return &dev->stats;
    }

    -/*
    - * Locking : hash tables are protected by RCU and RTNL
    - */
    -
    -static void ip6_tnl_per_cpu_dst_set(struct ip6_tnl_dst *idst,
    - struct dst_entry *dst)
    -{
    - write_seqlock_bh(&idst->lock);
    - dst_release(rcu_dereference_protected(
    - idst->dst,
    - lockdep_is_held(&idst->lock.lock)));
    - if (dst) {
    - dst_hold(dst);
    - idst->cookie = rt6_get_cookie((struct rt6_info *)dst);
    - } else {
    - idst->cookie = 0;
    - }
    - rcu_assign_pointer(idst->dst, dst);
    - write_sequnlock_bh(&idst->lock);
    -}
    -
    -struct dst_entry *ip6_tnl_dst_get(struct ip6_tnl *t)
    -{
    - struct ip6_tnl_dst *idst;
    - struct dst_entry *dst;
    - unsigned int seq;
    - u32 cookie;
    -
    - idst = raw_cpu_ptr(t->dst_cache);
    -
    - rcu_read_lock();
    - do {
    - seq = read_seqbegin(&idst->lock);
    - dst = rcu_dereference(idst->dst);
    - cookie = idst->cookie;
    - } while (read_seqretry(&idst->lock, seq));
    -
    - if (dst && !atomic_inc_not_zero(&dst->__refcnt))
    - dst = NULL;
    - rcu_read_unlock();
    -
    - if (dst && dst->obsolete && !dst->ops->check(dst, cookie)) {
    - ip6_tnl_per_cpu_dst_set(idst, NULL);
    - dst_release(dst);
    - dst = NULL;
    - }
    - return dst;
    -}
    -EXPORT_SYMBOL_GPL(ip6_tnl_dst_get);
    -
    -void ip6_tnl_dst_reset(struct ip6_tnl *t)
    -{
    - int i;
    -
    - for_each_possible_cpu(i)
    - ip6_tnl_per_cpu_dst_set(per_cpu_ptr(t->dst_cache, i), NULL);
    -}
    -EXPORT_SYMBOL_GPL(ip6_tnl_dst_reset);
    -
    -void ip6_tnl_dst_set(struct ip6_tnl *t, struct dst_entry *dst)
    -{
    - ip6_tnl_per_cpu_dst_set(raw_cpu_ptr(t->dst_cache), dst);
    -
    -}
    -EXPORT_SYMBOL_GPL(ip6_tnl_dst_set);
    -
    -void ip6_tnl_dst_destroy(struct ip6_tnl *t)
    -{
    - if (!t->dst_cache)
    - return;
    -
    - ip6_tnl_dst_reset(t);
    - free_percpu(t->dst_cache);
    -}
    -EXPORT_SYMBOL_GPL(ip6_tnl_dst_destroy);
    -
    -int ip6_tnl_dst_init(struct ip6_tnl *t)
    -{
    - int i;
    -
    - t->dst_cache = alloc_percpu(struct ip6_tnl_dst);
    - if (!t->dst_cache)
    - return -ENOMEM;
    -
    - for_each_possible_cpu(i)
    - seqlock_init(&per_cpu_ptr(t->dst_cache, i)->lock);
    -
    - return 0;
    -}
    -EXPORT_SYMBOL_GPL(ip6_tnl_dst_init);
    -
    /**
    * ip6_tnl_lookup - fetch tunnel matching the end-point addresses
    * @remote: the address of the tunnel exit-point
    @@ -331,7 +240,7 @@ static void ip6_dev_free(struct net_devi
    {
    struct ip6_tnl *t = netdev_priv(dev);

    - ip6_tnl_dst_destroy(t);
    + dst_cache_destroy(&t->dst_cache);
    free_percpu(dev->tstats);
    free_netdev(dev);
    }
    @@ -464,7 +373,7 @@ ip6_tnl_dev_uninit(struct net_device *de
    RCU_INIT_POINTER(ip6n->tnls_wc[0], NULL);
    else
    ip6_tnl_unlink(ip6n, t);
    - ip6_tnl_dst_reset(t);
    + dst_cache_reset(&t->dst_cache);
    dev_put(dev);
    }

    @@ -1053,7 +962,6 @@ static int ip6_tnl_xmit2(struct sk_buff
    struct ipv6_tel_txoption opt;
    struct dst_entry *dst = NULL, *ndst = NULL;
    struct net_device *tdev;
    - bool use_cache = false;
    int mtu;
    unsigned int max_headroom = sizeof(struct ipv6hdr);
    u8 proto;
    @@ -1061,39 +969,28 @@ static int ip6_tnl_xmit2(struct sk_buff

    /* NBMA tunnel */
    if (ipv6_addr_any(&t->parms.raddr)) {
    - if (skb->protocol == htons(ETH_P_IPV6)) {
    - struct in6_addr *addr6;
    - struct neighbour *neigh;
    - int addr_type;
    -
    - if (!skb_dst(skb))
    - goto tx_err_link_failure;
    -
    - neigh = dst_neigh_lookup(skb_dst(skb),
    - &ipv6_hdr(skb)->daddr);
    - if (!neigh)
    - goto tx_err_link_failure;
    + struct in6_addr *addr6;
    + struct neighbour *neigh;
    + int addr_type;
    +
    + if (!skb_dst(skb))
    + goto tx_err_link_failure;

    - addr6 = (struct in6_addr *)&neigh->primary_key;
    - addr_type = ipv6_addr_type(addr6);
    + neigh = dst_neigh_lookup(skb_dst(skb),
    + &ipv6_hdr(skb)->daddr);
    + if (!neigh)
    + goto tx_err_link_failure;

    - if (addr_type == IPV6_ADDR_ANY)
    - addr6 = &ipv6_hdr(skb)->daddr;
    + addr6 = (struct in6_addr *)&neigh->primary_key;
    + addr_type = ipv6_addr_type(addr6);

    - memcpy(&fl6->daddr, addr6, sizeof(fl6->daddr));
    - neigh_release(neigh);
    - }
    - } else if (t->parms.proto != 0 && !(t->parms.flags &
    - (IP6_TNL_F_USE_ORIG_TCLASS |
    - IP6_TNL_F_USE_ORIG_FWMARK))) {
    - /* enable the cache only if neither the outer protocol nor the
    - * routing decision depends on the current inner header value
    - */
    - use_cache = true;
    - }
    + if (addr_type == IPV6_ADDR_ANY)
    + addr6 = &ipv6_hdr(skb)->daddr;

    - if (use_cache)
    - dst = ip6_tnl_dst_get(t);
    + memcpy(&fl6->daddr, addr6, sizeof(fl6->daddr));
    + neigh_release(neigh);
    + } else if (!fl6->flowi6_mark)
    + dst = dst_cache_get(&t->dst_cache);

    if (!ip6_tnl_xmit_ctl(t, &fl6->saddr, &fl6->daddr))
    goto tx_err_link_failure;
    @@ -1156,8 +1053,8 @@ static int ip6_tnl_xmit2(struct sk_buff
    skb = new_skb;
    }

    - if (use_cache && ndst)
    - ip6_tnl_dst_set(t, ndst);
    + if (!fl6->flowi6_mark && ndst)
    + dst_cache_set_ip6(&t->dst_cache, ndst, &fl6->saddr);
    skb_dst_set(skb, dst);

    skb->transport_header = skb->network_header;
    @@ -1392,7 +1289,7 @@ ip6_tnl_change(struct ip6_tnl *t, const
    t->parms.flowinfo = p->flowinfo;
    t->parms.link = p->link;
    t->parms.proto = p->proto;
    - ip6_tnl_dst_reset(t);
    + dst_cache_reset(&t->dst_cache);
    ip6_tnl_link_config(t);
    return 0;
    }
    @@ -1663,7 +1560,7 @@ ip6_tnl_dev_init_gen(struct net_device *
    if (!dev->tstats)
    return -ENOMEM;

    - ret = ip6_tnl_dst_init(t);
    + ret = dst_cache_init(&t->dst_cache, GFP_KERNEL);
    if (ret) {
    free_percpu(dev->tstats);
    dev->tstats = NULL;
    --- a/net/ipv6/ip6_vti.c
    +++ b/net/ipv6/ip6_vti.c
    @@ -645,7 +645,7 @@ vti6_tnl_change(struct ip6_tnl *t, const
    t->parms.i_key = p->i_key;
    t->parms.o_key = p->o_key;
    t->parms.proto = p->proto;
    - ip6_tnl_dst_reset(t);
    + dst_cache_reset(&t->dst_cache);
    vti6_link_config(t);
    return 0;
    }

    \
     
     \ /
      Last update: 2018-02-23 21:43    [W:2.450 / U:0.052 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site