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// SPDX-License-Identifier: GPL-2.0-only
/*
* IPv6 library code, needed by static components when full IPv6 support is
* not configured or static. These functions are needed by GSO/GRO implementation.
*/
#include <linux/export.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <net/ip6_fib.h>
#include <net/addrconf.h>
#include <net/secure_seq.h>
#include <linux/netfilter.h>
static u32 __ipv6_select_ident(struct net *net,
const struct in6_addr *dst,
const struct in6_addr *src)
{
const struct {
struct in6_addr dst;
struct in6_addr src;
} __aligned(SIPHASH_ALIGNMENT) combined = {
.dst = *dst,
.src = *src,
};
u32 hash, id;
/* Note the following code is not safe, but this is okay. */
if (unlikely(siphash_key_is_zero(&net->ipv4.ip_id_key)))
get_random_bytes(&net->ipv4.ip_id_key,
sizeof(net->ipv4.ip_id_key));
hash = siphash(&combined, sizeof(combined), &net->ipv4.ip_id_key);
/* Treat id of 0 as unset and if we get 0 back from ip_idents_reserve,
* set the hight order instead thus minimizing possible future
* collisions.
*/
id = ip_idents_reserve(hash, 1);
if (unlikely(!id))
id = 1 << 31;
return id;
}
/* This function exists only for tap drivers that must support broken
* clients requesting UFO without specifying an IPv6 fragment ID.
*
* This is similar to ipv6_select_ident() but we use an independent hash
* seed to limit information leakage.
*
* The network header must be set before calling this.
*/
__be32 ipv6_proxy_select_ident(struct net *net, struct sk_buff *skb)
{
struct in6_addr buf[2];
struct in6_addr *addrs;
u32 id;
addrs = skb_header_pointer(skb,
skb_network_offset(skb) +
offsetof(struct ipv6hdr, saddr),
sizeof(buf), buf);
if (!addrs)
return 0;
id = __ipv6_select_ident(net, &addrs[1], &addrs[0]);
return htonl(id);
}
EXPORT_SYMBOL_GPL(ipv6_proxy_select_ident);
__be32 ipv6_select_ident(struct net *net,
const struct in6_addr *daddr,
const struct in6_addr *saddr)
{
u32 id;
id = __ipv6_select_ident(net, daddr, saddr);
return htonl(id);
}
EXPORT_SYMBOL(ipv6_select_ident);
int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
{
unsigned int offset = sizeof(struct ipv6hdr);
unsigned int packet_len = skb_tail_pointer(skb) -
skb_network_header(skb);
int found_rhdr = 0;
*nexthdr = &ipv6_hdr(skb)->nexthdr;
while (offset <= packet_len) {
struct ipv6_opt_hdr *exthdr;
switch (**nexthdr) {
case NEXTHDR_HOP:
break;
case NEXTHDR_ROUTING:
found_rhdr = 1;
break;
case NEXTHDR_DEST:
#if IS_ENABLED(CONFIG_IPV6_MIP6)
if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
break;
#endif
if (found_rhdr)
return offset;
break;
default:
return offset;
}
if (offset + sizeof(struct ipv6_opt_hdr) > packet_len)
return -EINVAL;
exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
offset);
offset += ipv6_optlen(exthdr);
if (offset > IPV6_MAXPLEN)
return -EINVAL;
*nexthdr = &exthdr->nexthdr;
}
return -EINVAL;
}
EXPORT_SYMBOL(ip6_find_1stfragopt);
#if IS_ENABLED(CONFIG_IPV6)
int ip6_dst_hoplimit(struct dst_entry *dst)
{
int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
if (hoplimit == 0) {
struct net_device *dev = dst->dev;
struct inet6_dev *idev;
rcu_read_lock();
idev = __in6_dev_get(dev);
if (idev)
hoplimit = idev->cnf.hop_limit;
else
hoplimit = dev_net(dev)->ipv6.devconf_all->hop_limit;
rcu_read_unlock();
}
return hoplimit;
}
EXPORT_SYMBOL(ip6_dst_hoplimit);
#endif
int __ip6_local_out(struct net *net, struct sock *sk, struct sk_buff *skb)
{
int len;
len = skb->len - sizeof(struct ipv6hdr);
if (len > IPV6_MAXPLEN)
len = 0;
ipv6_hdr(skb)->payload_len = htons(len);
IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
/* if egress device is enslaved to an L3 master device pass the
* skb to its handler for processing
*/
skb = l3mdev_ip6_out(sk, skb);
if (unlikely(!skb))
return 0;
skb->protocol = htons(ETH_P_IPV6);
return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
net, sk, skb, NULL, skb_dst(skb)->dev,
dst_output);
}
EXPORT_SYMBOL_GPL(__ip6_local_out);
int ip6_local_out(struct net *net, struct sock *sk, struct sk_buff *skb)
{
int err;
err = __ip6_local_out(net, sk, skb);
if (likely(err == 1))
err = dst_output(net, sk, skb);
return err;
}
EXPORT_SYMBOL_GPL(ip6_local_out);
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