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 | |
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(floor: 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 | */ |
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 | offset: skb_network_offset(skb) + |
37 | offsetof(struct ipv6hdr, saddr), |
38 | len: sizeof(buf), buffer: buf); |
39 | if (!addrs) |
40 | return 0; |
41 | |
42 | id = __ipv6_select_ident(net, dst: &addrs[1], src: &addrs[0]); |
43 | return htonl(id); |
44 | } |
45 | EXPORT_SYMBOL_GPL(ipv6_proxy_select_ident); |
46 | |
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, dst: daddr, src: saddr); |
54 | return htonl(id); |
55 | } |
56 | EXPORT_SYMBOL(ipv6_select_ident); |
57 | |
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) |
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 | |
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(pf: NFPROTO_IPV6, hook: NF_INET_LOCAL_OUT, |
144 | net, sk, skb, NULL, outdev: skb_dst(skb)->dev, |
145 | okfn: dst_output); |
146 | } |
147 | EXPORT_SYMBOL_GPL(__ip6_local_out); |
148 | |
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 | |