Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0-or-later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  *  IPv6 Syncookies implementation for the Linux kernel
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  *  Authors:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  *  Glenn Griffin	<ggriffin.kernel@gmail.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8)  *  Based on IPv4 implementation by Andi Kleen
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9)  *  linux/net/ipv4/syncookies.c
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) #include <linux/tcp.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) #include <linux/random.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) #include <linux/siphash.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) #include <linux/kernel.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) #include <net/secure_seq.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) #include <net/ipv6.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) #include <net/tcp.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) #define COOKIEBITS 24	/* Upper bits store count */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) #define COOKIEMASK (((__u32)1 << COOKIEBITS) - 1)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) static siphash_key_t syncookie6_secret[2] __read_mostly;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) /* RFC 2460, Section 8.3:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26)  * [ipv6 tcp] MSS must be computed as the maximum packet size minus 60 [..]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28)  * Due to IPV6_MIN_MTU=1280 the lowest possible MSS is 1220, which allows
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29)  * using higher values than ipv4 tcp syncookies.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30)  * The other values are chosen based on ethernet (1500 and 9k MTU), plus
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31)  * one that accounts for common encap (PPPoe) overhead. Table must be sorted.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) static __u16 const msstab[] = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) 	1280 - 60, /* IPV6_MIN_MTU - 60 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) 	1480 - 60,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) 	1500 - 60,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) 	9000 - 60,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) static u32 cookie_hash(const struct in6_addr *saddr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) 		       const struct in6_addr *daddr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 		       __be16 sport, __be16 dport, u32 count, int c)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 	const struct {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 		struct in6_addr saddr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 		struct in6_addr daddr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 		u32 count;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 		__be16 sport;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 		__be16 dport;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 	} __aligned(SIPHASH_ALIGNMENT) combined = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 		.saddr = *saddr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 		.daddr = *daddr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 		.count = count,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 		.sport = sport,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 		.dport = dport
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 	};
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 	net_get_random_once(syncookie6_secret, sizeof(syncookie6_secret));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 	return siphash(&combined, offsetofend(typeof(combined), dport),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 		       &syncookie6_secret[c]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) static __u32 secure_tcp_syn_cookie(const struct in6_addr *saddr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 				   const struct in6_addr *daddr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 				   __be16 sport, __be16 dport, __u32 sseq,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 				   __u32 data)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 	u32 count = tcp_cookie_time();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 	return (cookie_hash(saddr, daddr, sport, dport, 0, 0) +
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 		sseq + (count << COOKIEBITS) +
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 		((cookie_hash(saddr, daddr, sport, dport, count, 1) + data)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 		& COOKIEMASK));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) static __u32 check_tcp_syn_cookie(__u32 cookie, const struct in6_addr *saddr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 				  const struct in6_addr *daddr, __be16 sport,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 				  __be16 dport, __u32 sseq)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 	__u32 diff, count = tcp_cookie_time();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 	cookie -= cookie_hash(saddr, daddr, sport, dport, 0, 0) + sseq;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 	diff = (count - (cookie >> COOKIEBITS)) & ((__u32) -1 >> COOKIEBITS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 	if (diff >= MAX_SYNCOOKIE_AGE)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 		return (__u32)-1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 	return (cookie -
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 		cookie_hash(saddr, daddr, sport, dport, count - diff, 1))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 		& COOKIEMASK;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) u32 __cookie_v6_init_sequence(const struct ipv6hdr *iph,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 			      const struct tcphdr *th, __u16 *mssp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 	int mssind;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 	const __u16 mss = *mssp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 	for (mssind = ARRAY_SIZE(msstab) - 1; mssind ; mssind--)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 		if (mss >= msstab[mssind])
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 	*mssp = msstab[mssind];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 	return secure_tcp_syn_cookie(&iph->saddr, &iph->daddr, th->source,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 				     th->dest, ntohl(th->seq), mssind);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) EXPORT_SYMBOL_GPL(__cookie_v6_init_sequence);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) __u32 cookie_v6_init_sequence(const struct sk_buff *skb, __u16 *mssp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 	const struct ipv6hdr *iph = ipv6_hdr(skb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 	const struct tcphdr *th = tcp_hdr(skb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 	return __cookie_v6_init_sequence(iph, th, mssp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) int __cookie_v6_check(const struct ipv6hdr *iph, const struct tcphdr *th,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 		      __u32 cookie)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 	__u32 seq = ntohl(th->seq) - 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 	__u32 mssind = check_tcp_syn_cookie(cookie, &iph->saddr, &iph->daddr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 					    th->source, th->dest, seq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 	return mssind < ARRAY_SIZE(msstab) ? msstab[mssind] : 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) EXPORT_SYMBOL_GPL(__cookie_v6_check);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 	struct tcp_options_received tcp_opt;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 	struct inet_request_sock *ireq;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 	struct tcp_request_sock *treq;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 	struct ipv6_pinfo *np = inet6_sk(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 	struct tcp_sock *tp = tcp_sk(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 	const struct tcphdr *th = tcp_hdr(skb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 	__u32 cookie = ntohl(th->ack_seq) - 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 	struct sock *ret = sk;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 	struct request_sock *req;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 	int full_space, mss;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 	struct dst_entry *dst;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 	__u8 rcv_wscale;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 	u32 tsoff = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 	if (!sock_net(sk)->ipv4.sysctl_tcp_syncookies || !th->ack || th->rst)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 	if (tcp_synq_no_recent_overflow(sk))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 	mss = __cookie_v6_check(ipv6_hdr(skb), th, cookie);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 	if (mss == 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 		__NET_INC_STATS(sock_net(sk), LINUX_MIB_SYNCOOKIESFAILED);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 	__NET_INC_STATS(sock_net(sk), LINUX_MIB_SYNCOOKIESRECV);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 	/* check for timestamp cookie support */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 	memset(&tcp_opt, 0, sizeof(tcp_opt));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 	tcp_parse_options(sock_net(sk), skb, &tcp_opt, 0, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 	if (tcp_opt.saw_tstamp && tcp_opt.rcv_tsecr) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 		tsoff = secure_tcpv6_ts_off(sock_net(sk),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 					    ipv6_hdr(skb)->daddr.s6_addr32,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 					    ipv6_hdr(skb)->saddr.s6_addr32);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 		tcp_opt.rcv_tsecr -= tsoff;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 	if (!cookie_timestamp_decode(sock_net(sk), &tcp_opt))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 	ret = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 	req = cookie_tcp_reqsk_alloc(&tcp6_request_sock_ops, sk, skb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 	if (!req)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 	ireq = inet_rsk(req);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 	treq = tcp_rsk(req);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 	treq->tfo_listener = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 	if (security_inet_conn_request(sk, skb, req))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 		goto out_free;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 	req->mss = mss;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 	ireq->ir_rmt_port = th->source;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 	ireq->ir_num = ntohs(th->dest);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 	ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 	ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 	if (ipv6_opt_accepted(sk, skb, &TCP_SKB_CB(skb)->header.h6) ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 	    np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 	    np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 		refcount_inc(&skb->users);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 		ireq->pktopts = skb;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 	ireq->ir_iif = inet_request_bound_dev_if(sk, skb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 	/* So that link locals have meaning */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 	if (!sk->sk_bound_dev_if &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 	    ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 		ireq->ir_iif = tcp_v6_iif(skb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 	ireq->ir_mark = inet_request_mark(sk, skb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 	req->num_retrans = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 	ireq->snd_wscale	= tcp_opt.snd_wscale;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 	ireq->sack_ok		= tcp_opt.sack_ok;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 	ireq->wscale_ok		= tcp_opt.wscale_ok;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 	ireq->tstamp_ok		= tcp_opt.saw_tstamp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 	req->ts_recent		= tcp_opt.saw_tstamp ? tcp_opt.rcv_tsval : 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 	treq->snt_synack	= 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 	treq->rcv_isn = ntohl(th->seq) - 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 	treq->snt_isn = cookie;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 	treq->ts_off = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 	treq->txhash = net_tx_rndhash();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) 	if (IS_ENABLED(CONFIG_SMC))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 		ireq->smc_ok = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) 	 * We need to lookup the dst_entry to get the correct window size.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) 	 * This is taken from tcp_v6_syn_recv_sock.  Somebody please enlighten
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 	 * me if there is a preferred way.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) 	{
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) 		struct in6_addr *final_p, final;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) 		struct flowi6 fl6;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) 		memset(&fl6, 0, sizeof(fl6));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) 		fl6.flowi6_proto = IPPROTO_TCP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) 		fl6.daddr = ireq->ir_v6_rmt_addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) 		final_p = fl6_update_dst(&fl6, rcu_dereference(np->opt), &final);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) 		fl6.saddr = ireq->ir_v6_loc_addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) 		fl6.flowi6_oif = ireq->ir_iif;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) 		fl6.flowi6_mark = ireq->ir_mark;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) 		fl6.fl6_dport = ireq->ir_rmt_port;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) 		fl6.fl6_sport = inet_sk(sk)->inet_sport;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) 		fl6.flowi6_uid = sk->sk_uid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) 		security_req_classify_flow(req, flowi6_to_flowi(&fl6));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) 		dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) 		if (IS_ERR(dst))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) 			goto out_free;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) 	req->rsk_window_clamp = tp->window_clamp ? :dst_metric(dst, RTAX_WINDOW);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) 	/* limit the window selection if the user enforce a smaller rx buffer */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) 	full_space = tcp_full_space(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) 	if (sk->sk_userlocks & SOCK_RCVBUF_LOCK &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) 	    (req->rsk_window_clamp > full_space || req->rsk_window_clamp == 0))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) 		req->rsk_window_clamp = full_space;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) 	tcp_select_initial_window(sk, full_space, req->mss,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) 				  &req->rsk_rcv_wnd, &req->rsk_window_clamp,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) 				  ireq->wscale_ok, &rcv_wscale,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) 				  dst_metric(dst, RTAX_INITRWND));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) 	ireq->rcv_wscale = rcv_wscale;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 	ireq->ecn_ok = cookie_ecn_ok(&tcp_opt, sock_net(sk), dst);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) 	ret = tcp_get_cookie_sock(sk, skb, req, dst, tsoff);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) out_free:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) 	reqsk_free(req);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) 	return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) }