[mirror_ubuntu-bionic-kernel.git] / net / ipv6 / output_core.c

/*
 * 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>

static u32 __ipv6_select_ident(struct net *net, u32 hashrnd,
			       struct in6_addr *dst, struct in6_addr *src)
{
	u32 hash, id;

	hash = __ipv6_addr_jhash(dst, hashrnd);
	hash = __ipv6_addr_jhash(src, hash);
	hash ^= net_hash_mix(net);

	/* 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.
 */
void ipv6_proxy_select_ident(struct net *net, struct sk_buff *skb)
{
	static u32 ip6_proxy_idents_hashrnd __read_mostly;
	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;

	net_get_random_once(&ip6_proxy_idents_hashrnd,
			    sizeof(ip6_proxy_idents_hashrnd));

	id = __ipv6_select_ident(net, ip6_proxy_idents_hashrnd,
				 &addrs[1], &addrs[0]);
	skb_shinfo(skb)->ip6_frag_id = htonl(id);
}
EXPORT_SYMBOL_GPL(ipv6_proxy_select_ident);

u32 ipv6_select_ident(struct net *net, struct rt6_info *rt)
{
	static u32 ip6_idents_hashrnd __read_mostly;
	u32 id;

	net_get_random_once(&ip6_idents_hashrnd, sizeof(ip6_idents_hashrnd));

	id = __ipv6_select_ident(net, ip6_idents_hashrnd, &rt->rt6i_dst.addr,
				 &rt->rt6i_src.addr);
	return htonl(id);
}
EXPORT_SYMBOL(ipv6_select_ident);

int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
{
	u16 offset = sizeof(struct ipv6hdr);
	struct ipv6_opt_hdr *exthdr =
				(struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
	unsigned int packet_len = skb_tail_pointer(skb) -
		skb_network_header(skb);
	int found_rhdr = 0;
	*nexthdr = &ipv6_hdr(skb)->nexthdr;

	while (offset + 1 <= packet_len) {

		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;
		}

		offset += ipv6_optlen(exthdr);
		*nexthdr = &exthdr->nexthdr;
		exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
						 offset);
	}

	return offset;
}
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

static int __ip6_local_out_sk(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);

	return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, sk, skb,
		       NULL, skb_dst(skb)->dev, dst_output_sk);
}

int __ip6_local_out(struct sk_buff *skb)
{
	return __ip6_local_out_sk(skb->sk, skb);
}
EXPORT_SYMBOL_GPL(__ip6_local_out);

int ip6_local_out_sk(struct sock *sk, struct sk_buff *skb)
{
	int err;

	err = __ip6_local_out_sk(sk, skb);
	if (likely(err == 1))
		err = dst_output_sk(sk, skb);

	return err;
}
EXPORT_SYMBOL_GPL(ip6_local_out_sk);

int ip6_local_out(struct sk_buff *skb)
{
	return ip6_local_out_sk(skb->sk, skb);
}
EXPORT_SYMBOL_GPL(ip6_local_out);
Commit	Line	Data
3c73a036 VY	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>
5188cd44	6	#include <net/ip.h>
3c73a036 VY	7	#include <net/ipv6.h>
3c73a036 VY	8	#include <net/ip6_fib.h>
3ce9b35f	9	#include <net/addrconf.h>
6dfac5c3	10	#include <net/secure_seq.h>
3c73a036	11
5a352dd0 HFS	12	static u32 __ipv6_select_ident(struct net *net, u32 hashrnd,
5a352dd0 HFS	13	struct in6_addr dst, struct in6_addr src)
0508c07f VY	14	{
	15	u32 hash, id;
	16
	17	hash = __ipv6_addr_jhash(dst, hashrnd);
	18	hash = __ipv6_addr_jhash(src, hash);
5a352dd0	19	hash ^= net_hash_mix(net);
0508c07f VY	20
	21	/* Treat id of 0 as unset and if we get 0 back from ip_idents_reserve,
	22	* set the hight order instead thus minimizing possible future
	23	* collisions.
	24	*/
	25	id = ip_idents_reserve(hash, 1);
	26	if (unlikely(!id))
	27	id = 1 << 31;
	28
	29	return id;
	30	}
	31
5188cd44 BH	32	/* This function exists only for tap drivers that must support broken
	33	* clients requesting UFO without specifying an IPv6 fragment ID.
	34	*
	35	* This is similar to ipv6_select_ident() but we use an independent hash
	36	* seed to limit information leakage.
	37	*
	38	* The network header must be set before calling this.
	39	*/
5a352dd0	40	void ipv6_proxy_select_ident(struct net net, struct sk_buff skb)
5188cd44 BH	41	{
	42	static u32 ip6_proxy_idents_hashrnd __read_mostly;
	43	struct in6_addr buf[2];
	44	struct in6_addr *addrs;
0508c07f	45	u32 id;
5188cd44 BH	46
	47	addrs = skb_header_pointer(skb,
	48	skb_network_offset(skb) +
	49	offsetof(struct ipv6hdr, saddr),
	50	sizeof(buf), buf);
	51	if (!addrs)
	52	return;
	53
	54	net_get_random_once(&ip6_proxy_idents_hashrnd,
	55	sizeof(ip6_proxy_idents_hashrnd));
	56
5a352dd0	57	id = __ipv6_select_ident(net, ip6_proxy_idents_hashrnd,
0508c07f	58	&addrs[1], &addrs[0]);
51f30770	59	skb_shinfo(skb)->ip6_frag_id = htonl(id);
5188cd44 BH	60	}
	61	EXPORT_SYMBOL_GPL(ipv6_proxy_select_ident);
	62
286c2349	63	u32 ipv6_select_ident(struct net net, struct rt6_info rt)
0508c07f VY	64	{
	65	static u32 ip6_idents_hashrnd __read_mostly;
	66	u32 id;
	67
	68	net_get_random_once(&ip6_idents_hashrnd, sizeof(ip6_idents_hashrnd));
	69
5a352dd0	70	id = __ipv6_select_ident(net, ip6_idents_hashrnd, &rt->rt6i_dst.addr,
0508c07f	71	&rt->rt6i_src.addr);
286c2349	72	return htonl(id);
0508c07f VY	73	}
	74	EXPORT_SYMBOL(ipv6_select_ident);
	75
3c73a036 VY	76	int ip6_find_1stfragopt(struct sk_buff skb, u8 *nexthdr)
	77	{
	78	u16 offset = sizeof(struct ipv6hdr);
	79	struct ipv6_opt_hdr *exthdr =
	80	(struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
29a3cad5 SH	81	unsigned int packet_len = skb_tail_pointer(skb) -
29a3cad5 SH	82	skb_network_header(skb);
3c73a036 VY	83	int found_rhdr = 0;
	84	*nexthdr = &ipv6_hdr(skb)->nexthdr;
	85
	86	while (offset + 1 <= packet_len) {
	87
	88	switch (**nexthdr) {
	89
	90	case NEXTHDR_HOP:
	91	break;
	92	case NEXTHDR_ROUTING:
	93	found_rhdr = 1;
	94	break;
	95	case NEXTHDR_DEST:
	96	#if IS_ENABLED(CONFIG_IPV6_MIP6)
	97	if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
	98	break;
	99	#endif
	100	if (found_rhdr)
	101	return offset;
	102	break;
67ba4152	103	default:
3c73a036 VY	104	return offset;
	105	}
	106
	107	offset += ipv6_optlen(exthdr);
	108	*nexthdr = &exthdr->nexthdr;
	109	exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
	110	offset);
	111	}
	112
	113	return offset;
	114	}
	115	EXPORT_SYMBOL(ip6_find_1stfragopt);
3ce9b35f CW	116
	117	#if IS_ENABLED(CONFIG_IPV6)
	118	int ip6_dst_hoplimit(struct dst_entry *dst)
	119	{
	120	int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
	121	if (hoplimit == 0) {
	122	struct net_device *dev = dst->dev;
	123	struct inet6_dev *idev;
	124
	125	rcu_read_lock();
	126	idev = __in6_dev_get(dev);
	127	if (idev)
	128	hoplimit = idev->cnf.hop_limit;
	129	else
	130	hoplimit = dev_net(dev)->ipv6.devconf_all->hop_limit;
	131	rcu_read_unlock();
	132	}
	133	return hoplimit;
	134	}
	135	EXPORT_SYMBOL(ip6_dst_hoplimit);
	136	#endif
788787b5	137
79b16aad	138	static int __ip6_local_out_sk(struct sock sk, struct sk_buff skb)
788787b5 CW	139	{
	140	int len;
	141
	142	len = skb->len - sizeof(struct ipv6hdr);
	143	if (len > IPV6_MAXPLEN)
	144	len = 0;
	145	ipv6_hdr(skb)->payload_len = htons(len);
f6c20c59	146	IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
788787b5	147
79b16aad	148	return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, sk, skb,
7026b1dd	149	NULL, skb_dst(skb)->dev, dst_output_sk);
788787b5	150	}
79b16aad DM	151
	152	int __ip6_local_out(struct sk_buff *skb)
	153	{
	154	return __ip6_local_out_sk(skb->sk, skb);
	155	}
788787b5 CW	156	EXPORT_SYMBOL_GPL(__ip6_local_out);
788787b5 CW	157
79b16aad	158	int ip6_local_out_sk(struct sock sk, struct sk_buff skb)
788787b5 CW	159	{
	160	int err;
	161
79b16aad	162	err = __ip6_local_out_sk(sk, skb);
788787b5	163	if (likely(err == 1))
79b16aad	164	err = dst_output_sk(sk, skb);
788787b5 CW	165
	166	return err;
	167	}
79b16aad DM	168	EXPORT_SYMBOL_GPL(ip6_local_out_sk);
	169
	170	int ip6_local_out(struct sk_buff *skb)
	171	{
	172	return ip6_local_out_sk(skb->sk, skb);
	173	}
788787b5	174	EXPORT_SYMBOL_GPL(ip6_local_out);