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Commit 81eb6a14 authored by Patrick McHardy's avatar Patrick McHardy Committed by Pablo Neira Ayuso
Browse files

net: syncookies: export cookie_v6_init_sequence/cookie_v6_check 



Extract the local TCP stack independant parts of tcp_v6_init_sequence()
and cookie_v6_check() and export them for use by the upcoming IPv6 SYNPROXY
target.

Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
Tested-by: default avatarMartin Topholm <mph@one.com>
Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 48b1de4c

include/net/tcp.h

+4 −0
Original line number Diff line number Diff line
@@ -499,8 +499,12 @@ extern bool cookie_check_timestamp(struct tcp_options_received *opt, 
				struct net *net, bool *ecn_ok);



/* From net/ipv6/syncookies.c */

extern int __cookie_v6_check(const struct ipv6hdr *iph, const struct tcphdr *th,

			     u32 cookie);

extern struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb);

#ifdef CONFIG_SYN_COOKIES

extern u32 __cookie_v6_init_sequence(const struct ipv6hdr *iph,

				     const struct tcphdr *th, u16 *mssp);

extern __u32 cookie_v6_init_sequence(struct sock *sk, const struct sk_buff *skb,

				     __u16 *mss);

#else

net/ipv6/syncookies.c

+16 −9
Original line number Diff line number Diff line
@@ -112,32 +112,38 @@ static __u32 check_tcp_syn_cookie(__u32 cookie, const struct in6_addr *saddr, 
		& COOKIEMASK;

}



__u32 cookie_v6_init_sequence(struct sock *sk, const struct sk_buff *skb, __u16 *mssp)

u32 __cookie_v6_init_sequence(const struct ipv6hdr *iph,

			      const struct tcphdr *th, __u16 *mssp)

{

	const struct ipv6hdr *iph = ipv6_hdr(skb);

	const struct tcphdr *th = tcp_hdr(skb);

	int mssind;

	const __u16 mss = *mssp;



	tcp_synq_overflow(sk);



	for (mssind = ARRAY_SIZE(msstab) - 1; mssind ; mssind--)

		if (mss >= msstab[mssind])

			break;



	*mssp = msstab[mssind];



	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_SYNCOOKIESSENT);



	return secure_tcp_syn_cookie(&iph->saddr, &iph->daddr, th->source,

				     th->dest, ntohl(th->seq),

				     jiffies / (HZ * 60), mssind);

}

EXPORT_SYMBOL_GPL(__cookie_v6_init_sequence);



static inline int cookie_check(const struct sk_buff *skb, __u32 cookie)

__u32 cookie_v6_init_sequence(struct sock *sk, const struct sk_buff *skb, __u16 *mssp)

{

	const struct ipv6hdr *iph = ipv6_hdr(skb);

	const struct tcphdr *th = tcp_hdr(skb);



	tcp_synq_overflow(sk);

	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_SYNCOOKIESSENT);



	return __cookie_v6_init_sequence(iph, th, mssp);

}



int __cookie_v6_check(const struct ipv6hdr *iph, const struct tcphdr *th,

		      __u32 cookie)

{

	__u32 seq = ntohl(th->seq) - 1;

	__u32 mssind = check_tcp_syn_cookie(cookie, &iph->saddr, &iph->daddr,

					    th->source, th->dest, seq,
@@ -145,6 +151,7 @@ static inline int cookie_check(const struct sk_buff *skb, __u32 cookie) 


	return mssind < ARRAY_SIZE(msstab) ? msstab[mssind] : 0;

}

EXPORT_SYMBOL_GPL(__cookie_v6_check);



struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)

{
@@ -167,7 +174,7 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb) 
		goto out;



	if (tcp_synq_no_recent_overflow(sk) ||

		(mss = cookie_check(skb, cookie)) == 0) {

		(mss = __cookie_v6_check(ipv6_hdr(skb), th, cookie)) == 0) {

		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_SYNCOOKIESFAILED);

		goto out;

	}