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)
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
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
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
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
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
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
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