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 #include <linux/netfilter.h>
12
__ipv6_select_ident(struct net * net,const struct in6_addr * dst,const struct in6_addr * src)13 static u32 __ipv6_select_ident(struct net *net,
14 const struct in6_addr *dst,
15 const struct in6_addr *src)
16 {
17 u32 id;
18
19 do {
20 id = prandom_u32();
21 } while (!id);
22
23 return id;
24 }
25
26 /* This function exists only for tap drivers that must support broken
27 * clients requesting UFO without specifying an IPv6 fragment ID.
28 *
29 * This is similar to ipv6_select_ident() but we use an independent hash
30 * seed to limit information leakage.
31 *
32 * The network header must be set before calling this.
33 */
ipv6_proxy_select_ident(struct net * net,struct sk_buff * skb)34 void ipv6_proxy_select_ident(struct net *net, struct sk_buff *skb)
35 {
36 struct in6_addr buf[2];
37 struct in6_addr *addrs;
38 u32 id;
39
40 addrs = skb_header_pointer(skb,
41 skb_network_offset(skb) +
42 offsetof(struct ipv6hdr, saddr),
43 sizeof(buf), buf);
44 if (!addrs)
45 return;
46
47 id = __ipv6_select_ident(net, &addrs[1], &addrs[0]);
48 skb_shinfo(skb)->ip6_frag_id = htonl(id);
49 }
50 EXPORT_SYMBOL_GPL(ipv6_proxy_select_ident);
51
ipv6_select_ident(struct net * net,const struct in6_addr * daddr,const struct in6_addr * saddr)52 __be32 ipv6_select_ident(struct net *net,
53 const struct in6_addr *daddr,
54 const struct in6_addr *saddr)
55 {
56 u32 id;
57
58 id = __ipv6_select_ident(net, daddr, saddr);
59 return htonl(id);
60 }
61 EXPORT_SYMBOL(ipv6_select_ident);
62
ip6_find_1stfragopt(struct sk_buff * skb,u8 ** nexthdr)63 int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
64 {
65 unsigned int offset = sizeof(struct ipv6hdr);
66 unsigned int packet_len = skb_tail_pointer(skb) -
67 skb_network_header(skb);
68 int found_rhdr = 0;
69 *nexthdr = &ipv6_hdr(skb)->nexthdr;
70
71 while (offset <= packet_len) {
72 struct ipv6_opt_hdr *exthdr;
73
74 switch (**nexthdr) {
75
76 case NEXTHDR_HOP:
77 break;
78 case NEXTHDR_ROUTING:
79 found_rhdr = 1;
80 break;
81 case NEXTHDR_DEST:
82 #if IS_ENABLED(CONFIG_IPV6_MIP6)
83 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
84 break;
85 #endif
86 if (found_rhdr)
87 return offset;
88 break;
89 default:
90 return offset;
91 }
92
93 if (offset + sizeof(struct ipv6_opt_hdr) > packet_len)
94 return -EINVAL;
95
96 exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
97 offset);
98 offset += ipv6_optlen(exthdr);
99 if (offset > IPV6_MAXPLEN)
100 return -EINVAL;
101 *nexthdr = &exthdr->nexthdr;
102 }
103
104 return -EINVAL;
105 }
106 EXPORT_SYMBOL(ip6_find_1stfragopt);
107
108 #if IS_ENABLED(CONFIG_IPV6)
ip6_dst_hoplimit(struct dst_entry * dst)109 int ip6_dst_hoplimit(struct dst_entry *dst)
110 {
111 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
112 if (hoplimit == 0) {
113 struct net_device *dev = dst->dev;
114 struct inet6_dev *idev;
115
116 rcu_read_lock();
117 idev = __in6_dev_get(dev);
118 if (idev)
119 hoplimit = idev->cnf.hop_limit;
120 else
121 hoplimit = dev_net(dev)->ipv6.devconf_all->hop_limit;
122 rcu_read_unlock();
123 }
124 return hoplimit;
125 }
126 EXPORT_SYMBOL(ip6_dst_hoplimit);
127 #endif
128
__ip6_local_out(struct net * net,struct sock * sk,struct sk_buff * skb)129 int __ip6_local_out(struct net *net, struct sock *sk, struct sk_buff *skb)
130 {
131 int len;
132
133 len = skb->len - sizeof(struct ipv6hdr);
134 if (len > IPV6_MAXPLEN)
135 len = 0;
136 ipv6_hdr(skb)->payload_len = htons(len);
137 IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
138
139 skb->protocol = htons(ETH_P_IPV6);
140
141 return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
142 net, sk, skb, NULL, skb_dst(skb)->dev,
143 dst_output);
144 }
145 EXPORT_SYMBOL_GPL(__ip6_local_out);
146
ip6_local_out(struct net * net,struct sock * sk,struct sk_buff * skb)147 int ip6_local_out(struct net *net, struct sock *sk, struct sk_buff *skb)
148 {
149 int err;
150
151 err = __ip6_local_out(net, sk, skb);
152 if (likely(err == 1))
153 err = dst_output(net, sk, skb);
154
155 return err;
156 }
157 EXPORT_SYMBOL_GPL(ip6_local_out);
158