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 u32 id;
19
20 do {
21 id = get_random_u32();
22 } while (!id);
23
24 return id;
25 }
26
27 /* This function exists only for tap drivers that must support broken
28 * clients requesting UFO without specifying an IPv6 fragment ID.
29 *
30 * This is similar to ipv6_select_ident() but we use an independent hash
31 * seed to limit information leakage.
32 *
33 * The network header must be set before calling this.
34 */
ipv6_proxy_select_ident(struct net * net,struct sk_buff * skb)35 __be32 ipv6_proxy_select_ident(struct net *net, struct sk_buff *skb)
36 {
37 struct in6_addr buf[2];
38 struct in6_addr *addrs;
39 u32 id;
40
41 addrs = skb_header_pointer(skb,
42 skb_network_offset(skb) +
43 offsetof(struct ipv6hdr, saddr),
44 sizeof(buf), buf);
45 if (!addrs)
46 return 0;
47
48 id = __ipv6_select_ident(net, &addrs[1], &addrs[0]);
49 return htonl(id);
50 }
51 EXPORT_SYMBOL_GPL(ipv6_proxy_select_ident);
52
ipv6_select_ident(struct net * net,const struct in6_addr * daddr,const struct in6_addr * saddr)53 __be32 ipv6_select_ident(struct net *net,
54 const struct in6_addr *daddr,
55 const struct in6_addr *saddr)
56 {
57 u32 id;
58
59 id = __ipv6_select_ident(net, daddr, saddr);
60 return htonl(id);
61 }
62 EXPORT_SYMBOL(ipv6_select_ident);
63
ip6_find_1stfragopt(struct sk_buff * skb,u8 ** nexthdr)64 int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
65 {
66 unsigned int offset = sizeof(struct ipv6hdr);
67 unsigned int packet_len = skb_tail_pointer(skb) -
68 skb_network_header(skb);
69 int found_rhdr = 0;
70 *nexthdr = &ipv6_hdr(skb)->nexthdr;
71
72 while (offset <= packet_len) {
73 struct ipv6_opt_hdr *exthdr;
74
75 switch (**nexthdr) {
76
77 case NEXTHDR_HOP:
78 break;
79 case NEXTHDR_ROUTING:
80 found_rhdr = 1;
81 break;
82 case NEXTHDR_DEST:
83 #if IS_ENABLED(CONFIG_IPV6_MIP6)
84 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
85 break;
86 #endif
87 if (found_rhdr)
88 return offset;
89 break;
90 default:
91 return offset;
92 }
93
94 if (offset + sizeof(struct ipv6_opt_hdr) > packet_len)
95 return -EINVAL;
96
97 exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
98 offset);
99 offset += ipv6_optlen(exthdr);
100 if (offset > IPV6_MAXPLEN)
101 return -EINVAL;
102 *nexthdr = &exthdr->nexthdr;
103 }
104
105 return -EINVAL;
106 }
107 EXPORT_SYMBOL(ip6_find_1stfragopt);
108
109 #if IS_ENABLED(CONFIG_IPV6)
ip6_dst_hoplimit(struct dst_entry * dst)110 int ip6_dst_hoplimit(struct dst_entry *dst)
111 {
112 int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
113 if (hoplimit == 0) {
114 struct net_device *dev = dst->dev;
115 struct inet6_dev *idev;
116
117 rcu_read_lock();
118 idev = __in6_dev_get(dev);
119 if (idev)
120 hoplimit = idev->cnf.hop_limit;
121 else
122 hoplimit = dev_net(dev)->ipv6.devconf_all->hop_limit;
123 rcu_read_unlock();
124 }
125 return hoplimit;
126 }
127 EXPORT_SYMBOL(ip6_dst_hoplimit);
128 #endif
129
__ip6_local_out(struct net * net,struct sock * sk,struct sk_buff * skb)130 int __ip6_local_out(struct net *net, struct sock *sk, struct sk_buff *skb)
131 {
132 int len;
133
134 len = skb->len - sizeof(struct ipv6hdr);
135 if (len > IPV6_MAXPLEN)
136 len = 0;
137 ipv6_hdr(skb)->payload_len = htons(len);
138 IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
139
140 /* if egress device is enslaved to an L3 master device pass the
141 * skb to its handler for processing
142 */
143 skb = l3mdev_ip6_out(sk, skb);
144 if (unlikely(!skb))
145 return 0;
146
147 skb->protocol = htons(ETH_P_IPV6);
148
149 return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
150 net, sk, skb, NULL, skb_dst(skb)->dev,
151 dst_output);
152 }
153 EXPORT_SYMBOL_GPL(__ip6_local_out);
154
ip6_local_out(struct net * net,struct sock * sk,struct sk_buff * skb)155 int ip6_local_out(struct net *net, struct sock *sk, struct sk_buff *skb)
156 {
157 int err;
158
159 err = __ip6_local_out(net, sk, skb);
160 if (likely(err == 1))
161 err = dst_output(net, sk, skb);
162
163 return err;
164 }
165 EXPORT_SYMBOL_GPL(ip6_local_out);
166
