1/*
2 * IPv6 library code, needed by static components when full IPv6 support is
3 * not configured or static.  These functions are needed by GSO/GRO implementation.
4 */
5#include <linux/export.h>
6#include <net/ip.h>
7#include <net/ipv6.h>
8#include <net/ip6_fib.h>
9#include <net/addrconf.h>
10#include <net/secure_seq.h>
11
12/* This function exists only for tap drivers that must support broken
13 * clients requesting UFO without specifying an IPv6 fragment ID.
14 *
15 * This is similar to ipv6_select_ident() but we use an independent hash
16 * seed to limit information leakage.
17 *
18 * The network header must be set before calling this.
19 */
20void ipv6_proxy_select_ident(struct sk_buff *skb)
21{
22	static u32 ip6_proxy_idents_hashrnd __read_mostly;
23	struct in6_addr buf[2];
24	struct in6_addr *addrs;
25	u32 hash, id;
26
27	addrs = skb_header_pointer(skb,
28				   skb_network_offset(skb) +
29				   offsetof(struct ipv6hdr, saddr),
30				   sizeof(buf), buf);
31	if (!addrs)
32		return;
33
34	net_get_random_once(&ip6_proxy_idents_hashrnd,
35			    sizeof(ip6_proxy_idents_hashrnd));
36
37	hash = __ipv6_addr_jhash(&addrs[1], ip6_proxy_idents_hashrnd);
38	hash = __ipv6_addr_jhash(&addrs[0], hash);
39
40	id = ip_idents_reserve(hash, 1);
41	skb_shinfo(skb)->ip6_frag_id = htonl(id);
42}
43EXPORT_SYMBOL_GPL(ipv6_proxy_select_ident);
44
45int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
46{
47	u16 offset = sizeof(struct ipv6hdr);
48	struct ipv6_opt_hdr *exthdr =
49				(struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
50	unsigned int packet_len = skb_tail_pointer(skb) -
51		skb_network_header(skb);
52	int found_rhdr = 0;
53	*nexthdr = &ipv6_hdr(skb)->nexthdr;
54
55	while (offset + 1 <= packet_len) {
56
57		switch (**nexthdr) {
58
59		case NEXTHDR_HOP:
60			break;
61		case NEXTHDR_ROUTING:
62			found_rhdr = 1;
63			break;
64		case NEXTHDR_DEST:
65#if IS_ENABLED(CONFIG_IPV6_MIP6)
66			if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
67				break;
68#endif
69			if (found_rhdr)
70				return offset;
71			break;
72		default:
73			return offset;
74		}
75
76		offset += ipv6_optlen(exthdr);
77		*nexthdr = &exthdr->nexthdr;
78		exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
79						 offset);
80	}
81
82	return offset;
83}
84EXPORT_SYMBOL(ip6_find_1stfragopt);
85
86#if IS_ENABLED(CONFIG_IPV6)
87int ip6_dst_hoplimit(struct dst_entry *dst)
88{
89	int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
90	if (hoplimit == 0) {
91		struct net_device *dev = dst->dev;
92		struct inet6_dev *idev;
93
94		rcu_read_lock();
95		idev = __in6_dev_get(dev);
96		if (idev)
97			hoplimit = idev->cnf.hop_limit;
98		else
99			hoplimit = dev_net(dev)->ipv6.devconf_all->hop_limit;
100		rcu_read_unlock();
101	}
102	return hoplimit;
103}
104EXPORT_SYMBOL(ip6_dst_hoplimit);
105#endif
106
107int __ip6_local_out(struct sk_buff *skb)
108{
109	int len;
110
111	len = skb->len - sizeof(struct ipv6hdr);
112	if (len > IPV6_MAXPLEN)
113		len = 0;
114	ipv6_hdr(skb)->payload_len = htons(len);
115	IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
116
117	return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL,
118		       skb_dst(skb)->dev, dst_output);
119}
120EXPORT_SYMBOL_GPL(__ip6_local_out);
121
122int ip6_local_out(struct sk_buff *skb)
123{
124	int err;
125
126	err = __ip6_local_out(skb);
127	if (likely(err == 1))
128		err = dst_output(skb);
129
130	return err;
131}
132EXPORT_SYMBOL_GPL(ip6_local_out);
133