ipv6_frag.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef _IPV6_FRAG_H
  3#define _IPV6_FRAG_H
  4#include <linux/icmpv6.h>
  5#include <linux/kernel.h>
  6#include <net/addrconf.h>
  7#include <net/ipv6.h>
  8#include <net/inet_frag.h>
  9
 10enum ip6_defrag_users {
 11	IP6_DEFRAG_LOCAL_DELIVER,
 12	IP6_DEFRAG_CONNTRACK_IN,
 13	__IP6_DEFRAG_CONNTRACK_IN	= IP6_DEFRAG_CONNTRACK_IN + USHRT_MAX,
 14	IP6_DEFRAG_CONNTRACK_OUT,
 15	__IP6_DEFRAG_CONNTRACK_OUT	= IP6_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
 16	IP6_DEFRAG_CONNTRACK_BRIDGE_IN,
 17	__IP6_DEFRAG_CONNTRACK_BRIDGE_IN = IP6_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
 18};
 19
 20/*
 21 *	Equivalent of ipv4 struct ip
 22 */
 23struct frag_queue {
 24	struct inet_frag_queue	q;
 25
 26	int			iif;
 27	__u16			nhoffset;
 28	u8			ecn;
 29};
 30
 31#if IS_ENABLED(CONFIG_IPV6)
 32static inline void ip6frag_init(struct inet_frag_queue *q, const void *a)
 33{
 34	struct frag_queue *fq = container_of(q, struct frag_queue, q);
 35	const struct frag_v6_compare_key *key = a;
 36
 37	q->key.v6 = *key;
 38	fq->ecn = 0;
 39}
 40
 41static inline u32 ip6frag_key_hashfn(const void *data, u32 len, u32 seed)
 42{
 43	return jhash2(data,
 44		      sizeof(struct frag_v6_compare_key) / sizeof(u32), seed);
 45}
 46
 47static inline u32 ip6frag_obj_hashfn(const void *data, u32 len, u32 seed)
 48{
 49	const struct inet_frag_queue *fq = data;
 50
 51	return jhash2((const u32 *)&fq->key.v6,
 52		      sizeof(struct frag_v6_compare_key) / sizeof(u32), seed);
 53}
 54
 55static inline int
 56ip6frag_obj_cmpfn(struct rhashtable_compare_arg *arg, const void *ptr)
 57{
 58	const struct frag_v6_compare_key *key = arg->key;
 59	const struct inet_frag_queue *fq = ptr;
 60
 61	return !!memcmp(&fq->key, key, sizeof(*key));
 62}
 63
 64static inline void
 65ip6frag_expire_frag_queue(struct net *net, struct frag_queue *fq)
 66{
 67	struct net_device *dev = NULL;
 68	struct sk_buff *head;
 69	int refs = 1;
 70
 71	rcu_read_lock();
 72	spin_lock(&fq->q.lock);
 73
 74	if (fq->q.flags & INET_FRAG_COMPLETE)
 75		goto out;
 76
 77	fq->q.flags |= INET_FRAG_DROP;
 78	inet_frag_kill(&fq->q, &refs);
 79
 80	/* Paired with the WRITE_ONCE() in fqdir_pre_exit(). */
 81	if (READ_ONCE(fq->q.fqdir->dead)) {
 82		inet_frag_queue_flush(&fq->q, 0);
 83		goto out;
 84	}
 85
 86	dev = dev_get_by_index_rcu(net, fq->iif);
 87	if (!dev)
 88		goto out;
 89
 90	__IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
 91	__IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
 92
 93	/* Don't send error if the first segment did not arrive. */
 94	if (!(fq->q.flags & INET_FRAG_FIRST_IN))
 95		goto out;
 96
 97	/* sk_buff::dev and sk_buff::rbnode are unionized. So we
 98	 * pull the head out of the tree in order to be able to
 99	 * deal with head->dev.
100	 */
101	head = inet_frag_pull_head(&fq->q);
102	if (!head)
103		goto out;
104
105	head->dev = dev;
106	spin_unlock(&fq->q.lock);
107
108	icmpv6_send(head, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0);
109	kfree_skb_reason(head, SKB_DROP_REASON_FRAG_REASM_TIMEOUT);
110	goto out_rcu_unlock;
111
112out:
113	spin_unlock(&fq->q.lock);
114out_rcu_unlock:
115	rcu_read_unlock();
116	inet_frag_putn(&fq->q, refs);
117}
118
119/* Check if the upper layer header is truncated in the first fragment. */
120static inline bool
121ipv6frag_thdr_truncated(struct sk_buff *skb, int start, u8 *nexthdrp)
122{
123	u8 nexthdr = *nexthdrp;
124	__be16 frag_off;
125	int offset;
126
127	offset = ipv6_skip_exthdr(skb, start, &nexthdr, &frag_off);
128	if (offset < 0 || (frag_off & htons(IP6_OFFSET)))
129		return false;
130	switch (nexthdr) {
131	case NEXTHDR_TCP:
132		offset += sizeof(struct tcphdr);
133		break;
134	case NEXTHDR_UDP:
135		offset += sizeof(struct udphdr);
136		break;
137	case NEXTHDR_ICMP:
138		offset += sizeof(struct icmp6hdr);
139		break;
140	default:
141		offset += 1;
142	}
143	if (offset > skb->len)
144		return true;
145	return false;
146}
147
148#endif
149#endif