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 */
ipv6_proxy_select_ident(struct sk_buff * skb)20 void 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 }
43 EXPORT_SYMBOL_GPL(ipv6_proxy_select_ident);
44
ip6_find_1stfragopt(struct sk_buff * skb,u8 ** nexthdr)45 int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
46 {
47 unsigned int offset = sizeof(struct ipv6hdr);
48 unsigned int packet_len = skb_tail_pointer(skb) -
49 skb_network_header(skb);
50 int found_rhdr = 0;
51 *nexthdr = &ipv6_hdr(skb)->nexthdr;
52
53 while (offset <= packet_len) {
54 struct ipv6_opt_hdr *exthdr;
55
56 switch (**nexthdr) {
57
58 case NEXTHDR_HOP:
59 break;
60 case NEXTHDR_ROUTING:
61 found_rhdr = 1;
62 break;
63 case NEXTHDR_DEST:
64 #if IS_ENABLED(CONFIG_IPV6_MIP6)
65 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
66 break;
67 #endif
68 if (found_rhdr)
69 return offset;
70 break;
71 default:
72 return offset;
73 }
74
75 if (offset + sizeof(struct ipv6_opt_hdr) > packet_len)
76 return -EINVAL;
77
78 exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
79 offset);
80 offset += ipv6_optlen(exthdr);
81 if (offset > IPV6_MAXPLEN)
82 return -EINVAL;
83 *nexthdr = &exthdr->nexthdr;
84 }
85
86 return -EINVAL;
87 }
88 EXPORT_SYMBOL(ip6_find_1stfragopt);
89
90 #if IS_ENABLED(CONFIG_IPV6)
ip6_dst_hoplimit(struct dst_entry * dst)91 int ip6_dst_hoplimit(struct dst_entry *dst)
92 {
93 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
94 if (hoplimit == 0) {
95 struct net_device *dev = dst->dev;
96 struct inet6_dev *idev;
97
98 rcu_read_lock();
99 idev = __in6_dev_get(dev);
100 if (idev)
101 hoplimit = idev->cnf.hop_limit;
102 else
103 hoplimit = dev_net(dev)->ipv6.devconf_all->hop_limit;
104 rcu_read_unlock();
105 }
106 return hoplimit;
107 }
108 EXPORT_SYMBOL(ip6_dst_hoplimit);
109 #endif
110
__ip6_local_out(struct sk_buff * skb)111 int __ip6_local_out(struct sk_buff *skb)
112 {
113 int len;
114
115 len = skb->len - sizeof(struct ipv6hdr);
116 if (len > IPV6_MAXPLEN)
117 len = 0;
118 ipv6_hdr(skb)->payload_len = htons(len);
119 IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
120
121 return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL,
122 skb_dst(skb)->dev, dst_output);
123 }
124 EXPORT_SYMBOL_GPL(__ip6_local_out);
125
ip6_local_out(struct sk_buff * skb)126 int ip6_local_out(struct sk_buff *skb)
127 {
128 int err;
129
130 err = __ip6_local_out(skb);
131 if (likely(err == 1))
132 err = dst_output(skb);
133
134 return err;
135 }
136 EXPORT_SYMBOL_GPL(ip6_local_out);
137