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d4289fcc9b
Currently, IPv6 defragmentation code drops non-last fragments that
are smaller than 1280 bytes: see
commit 0ed4229b08 ("ipv6: defrag: drop non-last frags smaller than min mtu")
This behavior is not specified in IPv6 RFCs and appears to break
compatibility with some IPv6 implemenations, as reported here:
https://www.spinics.net/lists/netdev/msg543846.html
This patch re-uses common IP defragmentation queueing and reassembly
code in IPv6, removing the 1280 byte restriction.
Signed-off-by: Peter Oskolkov <posk@google.com>
Reported-by: Tom Herbert <tom@herbertland.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
112 lines
2.6 KiB
C
112 lines
2.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _IPV6_FRAG_H
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#define _IPV6_FRAG_H
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#include <linux/kernel.h>
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#include <net/addrconf.h>
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#include <net/ipv6.h>
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#include <net/inet_frag.h>
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enum ip6_defrag_users {
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IP6_DEFRAG_LOCAL_DELIVER,
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IP6_DEFRAG_CONNTRACK_IN,
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__IP6_DEFRAG_CONNTRACK_IN = IP6_DEFRAG_CONNTRACK_IN + USHRT_MAX,
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IP6_DEFRAG_CONNTRACK_OUT,
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__IP6_DEFRAG_CONNTRACK_OUT = IP6_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
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IP6_DEFRAG_CONNTRACK_BRIDGE_IN,
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__IP6_DEFRAG_CONNTRACK_BRIDGE_IN = IP6_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
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};
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/*
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* Equivalent of ipv4 struct ip
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*/
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struct frag_queue {
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struct inet_frag_queue q;
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int iif;
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__u16 nhoffset;
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u8 ecn;
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};
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#if IS_ENABLED(CONFIG_IPV6)
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static inline void ip6frag_init(struct inet_frag_queue *q, const void *a)
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{
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struct frag_queue *fq = container_of(q, struct frag_queue, q);
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const struct frag_v6_compare_key *key = a;
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q->key.v6 = *key;
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fq->ecn = 0;
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}
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static inline u32 ip6frag_key_hashfn(const void *data, u32 len, u32 seed)
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{
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return jhash2(data,
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sizeof(struct frag_v6_compare_key) / sizeof(u32), seed);
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}
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static inline u32 ip6frag_obj_hashfn(const void *data, u32 len, u32 seed)
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{
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const struct inet_frag_queue *fq = data;
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return jhash2((const u32 *)&fq->key.v6,
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sizeof(struct frag_v6_compare_key) / sizeof(u32), seed);
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}
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static inline int
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ip6frag_obj_cmpfn(struct rhashtable_compare_arg *arg, const void *ptr)
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{
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const struct frag_v6_compare_key *key = arg->key;
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const struct inet_frag_queue *fq = ptr;
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return !!memcmp(&fq->key, key, sizeof(*key));
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}
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static inline void
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ip6frag_expire_frag_queue(struct net *net, struct frag_queue *fq)
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{
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struct net_device *dev = NULL;
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struct sk_buff *head;
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rcu_read_lock();
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spin_lock(&fq->q.lock);
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if (fq->q.flags & INET_FRAG_COMPLETE)
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goto out;
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inet_frag_kill(&fq->q);
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dev = dev_get_by_index_rcu(net, fq->iif);
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if (!dev)
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goto out;
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__IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
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__IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
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/* Don't send error if the first segment did not arrive. */
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if (!(fq->q.flags & INET_FRAG_FIRST_IN))
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goto out;
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/* sk_buff::dev and sk_buff::rbnode are unionized. So we
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* pull the head out of the tree in order to be able to
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* deal with head->dev.
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*/
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head = inet_frag_pull_head(&fq->q);
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if (!head)
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goto out;
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head->dev = dev;
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skb_get(head);
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spin_unlock(&fq->q.lock);
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icmpv6_send(head, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0);
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kfree_skb(head);
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goto out_rcu_unlock;
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out:
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spin_unlock(&fq->q.lock);
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out_rcu_unlock:
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rcu_read_unlock();
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inet_frag_put(&fq->q);
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}
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#endif
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#endif
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