xref: /linux/include/net/ipv6_frag.h (revision 7ae9fb1b7ecbb5d85d07857943f677fd1a559b18)
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 
10 enum 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  */
23 struct 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)
ip6frag_init(struct inet_frag_queue * q,const void * a)32 static 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 
ip6frag_key_hashfn(const void * data,u32 len,u32 seed)41 static 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 
ip6frag_obj_hashfn(const void * data,u32 len,u32 seed)47 static 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 
55 static inline int
ip6frag_obj_cmpfn(struct rhashtable_compare_arg * arg,const void * ptr)56 ip6frag_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 
64 static inline void
ip6frag_expire_frag_queue(struct net * net,struct frag_queue * fq)65 ip6frag_expire_frag_queue(struct net *net, struct frag_queue *fq)
66 {
67 	struct net_device *dev = NULL;
68 	struct sk_buff *head;
69 
70 	rcu_read_lock();
71 	/* Paired with the WRITE_ONCE() in fqdir_pre_exit(). */
72 	if (READ_ONCE(fq->q.fqdir->dead))
73 		goto out_rcu_unlock;
74 	spin_lock(&fq->q.lock);
75 
76 	if (fq->q.flags & INET_FRAG_COMPLETE)
77 		goto out;
78 
79 	fq->q.flags |= INET_FRAG_DROP;
80 	inet_frag_kill(&fq->q);
81 
82 	dev = dev_get_by_index_rcu(net, fq->iif);
83 	if (!dev)
84 		goto out;
85 
86 	__IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);
87 	__IP6_INC_STATS(net, __in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);
88 
89 	/* Don't send error if the first segment did not arrive. */
90 	if (!(fq->q.flags & INET_FRAG_FIRST_IN))
91 		goto out;
92 
93 	/* sk_buff::dev and sk_buff::rbnode are unionized. So we
94 	 * pull the head out of the tree in order to be able to
95 	 * deal with head->dev.
96 	 */
97 	head = inet_frag_pull_head(&fq->q);
98 	if (!head)
99 		goto out;
100 
101 	head->dev = dev;
102 	spin_unlock(&fq->q.lock);
103 
104 	icmpv6_send(head, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0);
105 	kfree_skb_reason(head, SKB_DROP_REASON_FRAG_REASM_TIMEOUT);
106 	goto out_rcu_unlock;
107 
108 out:
109 	spin_unlock(&fq->q.lock);
110 out_rcu_unlock:
111 	rcu_read_unlock();
112 	inet_frag_put(&fq->q);
113 }
114 
115 /* Check if the upper layer header is truncated in the first fragment. */
116 static inline bool
ipv6frag_thdr_truncated(struct sk_buff * skb,int start,u8 * nexthdrp)117 ipv6frag_thdr_truncated(struct sk_buff *skb, int start, u8 *nexthdrp)
118 {
119 	u8 nexthdr = *nexthdrp;
120 	__be16 frag_off;
121 	int offset;
122 
123 	offset = ipv6_skip_exthdr(skb, start, &nexthdr, &frag_off);
124 	if (offset < 0 || (frag_off & htons(IP6_OFFSET)))
125 		return false;
126 	switch (nexthdr) {
127 	case NEXTHDR_TCP:
128 		offset += sizeof(struct tcphdr);
129 		break;
130 	case NEXTHDR_UDP:
131 		offset += sizeof(struct udphdr);
132 		break;
133 	case NEXTHDR_ICMP:
134 		offset += sizeof(struct icmp6hdr);
135 		break;
136 	default:
137 		offset += 1;
138 	}
139 	if (offset > skb->len)
140 		return true;
141 	return false;
142 }
143 
144 #endif
145 #endif
146