1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * IPv6 library code, needed by static components when full IPv6 support is
4 * not configured or static. These functions are needed by GSO/GRO implementation.
5 */
6 #include <linux/export.h>
7 #include <net/ip.h>
8 #include <net/ipv6.h>
9 #include <net/ip6_fib.h>
10 #include <net/addrconf.h>
11 #include <net/secure_seq.h>
12 #include <linux/netfilter.h>
13
__ipv6_select_ident(struct net * net,const struct in6_addr * dst,const struct in6_addr * src)14 static u32 __ipv6_select_ident(struct net *net,
15 const struct in6_addr *dst,
16 const struct in6_addr *src)
17 {
18 return get_random_u32_above(0);
19 }
20
21 /* This function exists only for tap drivers that must support broken
22 * clients requesting UFO without specifying an IPv6 fragment ID.
23 *
24 * This is similar to ipv6_select_ident() but we use an independent hash
25 * seed to limit information leakage.
26 *
27 * The network header must be set before calling this.
28 */
ipv6_proxy_select_ident(struct net * net,struct sk_buff * skb)29 __be32 ipv6_proxy_select_ident(struct net *net, struct sk_buff *skb)
30 {
31 struct in6_addr buf[2];
32 struct in6_addr *addrs;
33 u32 id;
34
35 addrs = skb_header_pointer(skb,
36 skb_network_offset(skb) +
37 offsetof(struct ipv6hdr, saddr),
38 sizeof(buf), buf);
39 if (!addrs)
40 return 0;
41
42 id = __ipv6_select_ident(net, &addrs[1], &addrs[0]);
43 return htonl(id);
44 }
45 EXPORT_SYMBOL_GPL(ipv6_proxy_select_ident);
46
ipv6_select_ident(struct net * net,const struct in6_addr * daddr,const struct in6_addr * saddr)47 __be32 ipv6_select_ident(struct net *net,
48 const struct in6_addr *daddr,
49 const struct in6_addr *saddr)
50 {
51 u32 id;
52
53 id = __ipv6_select_ident(net, daddr, saddr);
54 return htonl(id);
55 }
56 EXPORT_SYMBOL(ipv6_select_ident);
57
ip6_find_1stfragopt(struct sk_buff * skb,u8 ** nexthdr)58 int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
59 {
60 unsigned int offset = sizeof(struct ipv6hdr);
61 unsigned int packet_len = skb_tail_pointer(skb) -
62 skb_network_header(skb);
63 int found_rhdr = 0;
64 *nexthdr = &ipv6_hdr(skb)->nexthdr;
65
66 while (offset <= packet_len) {
67 struct ipv6_opt_hdr *exthdr;
68
69 switch (**nexthdr) {
70
71 case NEXTHDR_HOP:
72 break;
73 case NEXTHDR_ROUTING:
74 found_rhdr = 1;
75 break;
76 case NEXTHDR_DEST:
77 #if IS_ENABLED(CONFIG_IPV6_MIP6)
78 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
79 break;
80 #endif
81 if (found_rhdr)
82 return offset;
83 break;
84 default:
85 return offset;
86 }
87
88 if (offset + sizeof(struct ipv6_opt_hdr) > packet_len)
89 return -EINVAL;
90
91 exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
92 offset);
93 offset += ipv6_optlen(exthdr);
94 if (offset > IPV6_MAXPLEN)
95 return -EINVAL;
96 *nexthdr = &exthdr->nexthdr;
97 }
98
99 return -EINVAL;
100 }
101 EXPORT_SYMBOL(ip6_find_1stfragopt);
102
103 #if IS_ENABLED(CONFIG_IPV6)
ip6_dst_hoplimit(struct dst_entry * dst)104 int ip6_dst_hoplimit(struct dst_entry *dst)
105 {
106 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
107 if (hoplimit == 0) {
108 struct net_device *dev = dst->dev;
109 struct inet6_dev *idev;
110
111 rcu_read_lock();
112 idev = __in6_dev_get(dev);
113 if (idev)
114 hoplimit = idev->cnf.hop_limit;
115 else
116 hoplimit = dev_net(dev)->ipv6.devconf_all->hop_limit;
117 rcu_read_unlock();
118 }
119 return hoplimit;
120 }
121 EXPORT_SYMBOL(ip6_dst_hoplimit);
122 #endif
123
__ip6_local_out(struct net * net,struct sock * sk,struct sk_buff * skb)124 int __ip6_local_out(struct net *net, struct sock *sk, struct sk_buff *skb)
125 {
126 int len;
127
128 len = skb->len - sizeof(struct ipv6hdr);
129 if (len > IPV6_MAXPLEN)
130 len = 0;
131 ipv6_hdr(skb)->payload_len = htons(len);
132 IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
133
134 /* if egress device is enslaved to an L3 master device pass the
135 * skb to its handler for processing
136 */
137 skb = l3mdev_ip6_out(sk, skb);
138 if (unlikely(!skb))
139 return 0;
140
141 skb->protocol = htons(ETH_P_IPV6);
142
143 return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
144 net, sk, skb, NULL, skb_dst(skb)->dev,
145 dst_output);
146 }
147 EXPORT_SYMBOL_GPL(__ip6_local_out);
148
ip6_local_out(struct net * net,struct sock * sk,struct sk_buff * skb)149 int ip6_local_out(struct net *net, struct sock *sk, struct sk_buff *skb)
150 {
151 int err;
152
153 err = __ip6_local_out(net, sk, skb);
154 if (likely(err == 1))
155 err = dst_output(net, sk, skb);
156
157 return err;
158 }
159 EXPORT_SYMBOL_GPL(ip6_local_out);
160