aboutsummaryrefslogtreecommitdiffstats
path: root/net/ipv6/output_core.c
blob: 928a0fb0b74406cdf32c89fe7db054b40476dc54 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
/*
 * IPv6 library code, needed by static components when full IPv6 support is
 * not configured or static.  These functions are needed by GSO/GRO implementation.
 */
#include <linux/export.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <net/ip6_fib.h>
#include <net/addrconf.h>
#include <net/secure_seq.h>
#include <linux/netfilter.h>

static u32 __ipv6_select_ident(struct net *net, u32 hashrnd,
			       const struct in6_addr *dst,
			       const struct in6_addr *src)
{
	u32 hash, id;

	hash = __ipv6_addr_jhash(dst, hashrnd);
	hash = __ipv6_addr_jhash(src, hash);
	hash ^= net_hash_mix(net);

	/* Treat id of 0 as unset and if we get 0 back from ip_idents_reserve,
	 * set the hight order instead thus minimizing possible future
	 * collisions.
	 */
	id = ip_idents_reserve(hash, 1);
	if (unlikely(!id))
		id = 1 << 31;

	return id;
}

/* This function exists only for tap drivers that must support broken
 * clients requesting UFO without specifying an IPv6 fragment ID.
 *
 * This is similar to ipv6_select_ident() but we use an independent hash
 * seed to limit information leakage.
 *
 * The network header must be set before calling this.
 */
void ipv6_proxy_select_ident(struct net *net, struct sk_buff *skb)
{
	static u32 ip6_proxy_idents_hashrnd __read_mostly;
	struct in6_addr buf[2];
	struct in6_addr *addrs;
	u32 id;

	addrs = skb_header_pointer(skb,
				   skb_network_offset(skb) +
				   offsetof(struct ipv6hdr, saddr),
				   sizeof(buf), buf);
	if (!addrs)
		return;

	net_get_random_once(&ip6_proxy_idents_hashrnd,
			    sizeof(ip6_proxy_idents_hashrnd));

	id = __ipv6_select_ident(net, ip6_proxy_idents_hashrnd,
				 &addrs[1], &addrs[0]);
	skb_shinfo(skb)->ip6_frag_id = htonl(id);
}
EXPORT_SYMBOL_GPL(ipv6_proxy_select_ident);

__be32 ipv6_select_ident(struct net *net,
			 const struct in6_addr *daddr,
			 const struct in6_addr *saddr)
{
	static u32 ip6_idents_hashrnd __read_mostly;
	u32 id;

	net_get_random_once(&ip6_idents_hashrnd, sizeof(ip6_idents_hashrnd));

	id = __ipv6_select_ident(net, ip6_idents_hashrnd, daddr, saddr);
	return htonl(id);
}
EXPORT_SYMBOL(ipv6_select_ident);

int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
{
	u16 offset = sizeof(struct ipv6hdr);
	struct ipv6_opt_hdr *exthdr =
				(struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
	unsigned int packet_len = skb_tail_pointer(skb) -
		skb_network_header(skb);
	int found_rhdr = 0;
	*nexthdr = &ipv6_hdr(skb)->nexthdr;

	while (offset + 1 <= packet_len) {

		switch (**nexthdr) {

		case NEXTHDR_HOP:
			break;
		case NEXTHDR_ROUTING:
			found_rhdr = 1;
			break;
		case NEXTHDR_DEST:
#if IS_ENABLED(CONFIG_IPV6_MIP6)
			if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
				break;
#endif
			if (found_rhdr)
				return offset;
			break;
		default:
			return offset;
		}

		offset += ipv6_optlen(exthdr);
		*nexthdr = &exthdr->nexthdr;
		exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
						 offset);
	}

	return offset;
}
EXPORT_SYMBOL(ip6_find_1stfragopt);

#if IS_ENABLED(CONFIG_IPV6)
int ip6_dst_hoplimit(struct dst_entry *dst)
{
	int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
	if (hoplimit == 0) {
		struct net_device *dev = dst->dev;
		struct inet6_dev *idev;

		rcu_read_lock();
		idev = __in6_dev_get(dev);
		if (idev)
			hoplimit = idev->cnf.hop_limit;
		else
			hoplimit = dev_net(dev)->ipv6.devconf_all->hop_limit;
		rcu_read_unlock();
	}
	return hoplimit;
}
EXPORT_SYMBOL(ip6_dst_hoplimit);
#endif

static int __ip6_local_out_sk(struct sock *sk, struct sk_buff *skb)
{
	int len;

	len = skb->len - sizeof(struct ipv6hdr);
	if (len > IPV6_MAXPLEN)
		len = 0;
	ipv6_hdr(skb)->payload_len = htons(len);
	IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);

	return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, sk, skb,
		       NULL, skb_dst(skb)->dev, dst_output_sk);
}

int __ip6_local_out(struct sk_buff *skb)
{
	return __ip6_local_out_sk(skb->sk, skb);
}
EXPORT_SYMBOL_GPL(__ip6_local_out);

int ip6_local_out_sk(struct sock *sk, struct sk_buff *skb)
{
	int err;

	err = __ip6_local_out_sk(sk, skb);
	if (likely(err == 1))
		err = dst_output_sk(sk, skb);

	return err;
}
EXPORT_SYMBOL_GPL(ip6_local_out_sk);

int ip6_local_out(struct sk_buff *skb)
{
	return ip6_local_out_sk(skb->sk, skb);
}
EXPORT_SYMBOL_GPL(ip6_local_out);

Privacy Policy