inet: frags: get rif of inet_frag_evicting()

BugLink: https://bugs.launchpad.net/bugs/1836117
This refactors ip_expire() since one indentation level is removed.

Note: in the future, we should try hard to avoid the skb_clone()
since this is a serious performance cost.
Under DDOS, the ICMP message wont be sent because of rate limits.

Fact that ip6_expire_frag_queue() does not use skb_clone() is
disturbing too. Presumably IPv6 should have the same
issue than the one we fixed in commit ec4fbd64751d
("inet: frag: release spinlock before calling icmp_send()")

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 399d1404be660d355192ff4df5ccc3f4159ec1e4)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/include/net/inet_frag.h b/include/net/inet_frag.h
index 4b5449df0aadf1f75144c98317bf5305ec91d88b..0e8e159d88f7f77254fae5a49f1c7ba07b967e11 100644 (file)
--- a/include/net/inet_frag.h
+++ b/include/net/inet_frag.h
@@ -119,11 +119,6 @@ static inline void inet_frag_put(struct inet_frag_queue *q)
                inet_frag_destroy(q);
 }
 
-static inline bool inet_frag_evicting(struct inet_frag_queue *q)
-{
-       return false;
-}
-
 /* Memory Tracking Functions. */
 
 static inline int frag_mem_limit(struct netns_frags *nf)

diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index 68edffcf3df63ec1c10a97649d62c11b47131449..c0f8d27d0ba0b48b8b5f69c268333e7e60443939 100644 (file)
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -143,8 +143,11 @@ static bool frag_expire_skip_icmp(u32 user)
 static void ip_expire(struct timer_list *t)
 {
        struct inet_frag_queue *frag = from_timer(frag, t, timer);
-       struct ipq *qp;
+       struct sk_buff *clone, *head;
+       const struct iphdr *iph;
        struct net *net;
+       struct ipq *qp;
+       int err;
 
        qp = container_of(frag, struct ipq, q);
        net = container_of(qp->q.net, struct net, ipv4.frags);
@@ -158,45 +161,41 @@ static void ip_expire(struct timer_list *t)
        ipq_kill(qp);
        __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS);
 
-       if (!inet_frag_evicting(&qp->q)) {
-               struct sk_buff *clone, *head = qp->q.fragments;
-               const struct iphdr *iph;
-               int err;
+       head = qp->q.fragments;
 
-               __IP_INC_STATS(net, IPSTATS_MIB_REASMTIMEOUT);
+       __IP_INC_STATS(net, IPSTATS_MIB_REASMTIMEOUT);
 
-               if (!(qp->q.flags & INET_FRAG_FIRST_IN) || !qp->q.fragments)
-                       goto out;
+       if (!(qp->q.flags & INET_FRAG_FIRST_IN) || !head)
+               goto out;
 
-               head->dev = dev_get_by_index_rcu(net, qp->iif);
-               if (!head->dev)
-                       goto out;
+       head->dev = dev_get_by_index_rcu(net, qp->iif);
+       if (!head->dev)
+               goto out;
 
 
-               /* skb has no dst, perform route lookup again */
-               iph = ip_hdr(head);
-               err = ip_route_input_noref(head, iph->daddr, iph->saddr,
+       /* skb has no dst, perform route lookup again */
+       iph = ip_hdr(head);
+       err = ip_route_input_noref(head, iph->daddr, iph->saddr,
                                           iph->tos, head->dev);
-               if (err)
-                       goto out;
+       if (err)
+               goto out;
 
-               /* Only an end host needs to send an ICMP
-                * "Fragment Reassembly Timeout" message, per RFC792.
-                */
-               if (frag_expire_skip_icmp(qp->q.key.v4.user) &&
-                   (skb_rtable(head)->rt_type != RTN_LOCAL))
-                       goto out;
-
-               clone = skb_clone(head, GFP_ATOMIC);
-
-               /* Send an ICMP "Fragment Reassembly Timeout" message. */
-               if (clone) {
-                       spin_unlock(&qp->q.lock);
-                       icmp_send(clone, ICMP_TIME_EXCEEDED,
-                                 ICMP_EXC_FRAGTIME, 0);
-                       consume_skb(clone);
-                       goto out_rcu_unlock;
-               }
+       /* Only an end host needs to send an ICMP
+        * "Fragment Reassembly Timeout" message, per RFC792.
+        */
+       if (frag_expire_skip_icmp(qp->q.key.v4.user) &&
+           (skb_rtable(head)->rt_type != RTN_LOCAL))
+               goto out;
+
+       clone = skb_clone(head, GFP_ATOMIC);
+
+       /* Send an ICMP "Fragment Reassembly Timeout" message. */
+       if (clone) {
+               spin_unlock(&qp->q.lock);
+               icmp_send(clone, ICMP_TIME_EXCEEDED,
+                         ICMP_EXC_FRAGTIME, 0);
+               consume_skb(clone);
+               goto out_rcu_unlock;
        }
 out:
        spin_unlock(&qp->q.lock);

diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c
index 3fc853e4492abb109062d662296c0b470763042a..70acad126d044a0f6a1efc63f307805fcf7b1df9 100644 (file)
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -106,10 +106,6 @@ void ip6_expire_frag_queue(struct net *net, struct frag_queue *fq)
                goto out_rcu_unlock;
 
        __IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
-
-       if (inet_frag_evicting(&fq->q))
-               goto out_rcu_unlock;
-
        __IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
 
        /* Don't send error if the first segment did not arrive. */