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-rw-r--r--net/ipv6/syncookies.c58
1 files changed, 22 insertions, 36 deletions
diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c
index 34d1f06..09fd34f 100644
--- a/net/ipv6/syncookies.c
+++ b/net/ipv6/syncookies.c
@@ -27,28 +27,17 @@ extern __u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS];
#define COOKIEBITS 24 /* Upper bits store count */
#define COOKIEMASK (((__u32)1 << COOKIEBITS) - 1)
-/*
- * This table has to be sorted and terminated with (__u16)-1.
- * XXX generate a better table.
- * Unresolved Issues: HIPPI with a 64k MSS is not well supported.
- *
- * Taken directly from ipv4 implementation.
- * Should this list be modified for ipv6 use or is it close enough?
- * rfc 2460 8.3 suggests mss values 20 bytes less than ipv4 counterpart
- */
+/* Table must be sorted. */
static __u16 const msstab[] = {
- 64 - 1,
- 256 - 1,
- 512 - 1,
- 536 - 1,
- 1024 - 1,
- 1440 - 1,
- 1460 - 1,
- 4312 - 1,
- (__u16)-1
+ 64,
+ 512,
+ 536,
+ 1280 - 60,
+ 1480 - 60,
+ 1500 - 60,
+ 4460 - 60,
+ 9000 - 60,
};
-/* The number doesn't include the -1 terminator */
-#define NUM_MSS (ARRAY_SIZE(msstab) - 1)
/*
* This (misnamed) value is the age of syncookie which is permitted.
@@ -134,9 +123,11 @@ __u32 cookie_v6_init_sequence(struct sock *sk, struct sk_buff *skb, __u16 *mssp)
tcp_synq_overflow(sk);
- for (mssind = 0; mss > msstab[mssind + 1]; mssind++)
- ;
- *mssp = msstab[mssind] + 1;
+ 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);
@@ -154,7 +145,7 @@ static inline int cookie_check(struct sk_buff *skb, __u32 cookie)
th->source, th->dest, seq,
jiffies / (HZ * 60), COUNTER_TRIES);
- return mssind < NUM_MSS ? msstab[mssind] + 1 : 0;
+ return mssind < ARRAY_SIZE(msstab) ? msstab[mssind] : 0;
}
struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
@@ -173,8 +164,9 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
int mss;
struct dst_entry *dst;
__u8 rcv_wscale;
+ bool ecn_ok;
- if (!sysctl_tcp_syncookies || !th->ack)
+ if (!sysctl_tcp_syncookies || !th->ack || th->rst)
goto out;
if (tcp_synq_no_recent_overflow(sk) ||
@@ -189,8 +181,8 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
memset(&tcp_opt, 0, sizeof(tcp_opt));
tcp_parse_options(skb, &tcp_opt, &hash_location, 0);
- if (tcp_opt.saw_tstamp)
- cookie_check_timestamp(&tcp_opt);
+ if (!cookie_check_timestamp(&tcp_opt, &ecn_ok))
+ goto out;
ret = NULL;
req = inet6_reqsk_alloc(&tcp6_request_sock_ops);
@@ -224,9 +216,8 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
req->expires = 0UL;
req->retrans = 0;
- ireq->ecn_ok = 0;
+ ireq->ecn_ok = ecn_ok;
ireq->snd_wscale = tcp_opt.snd_wscale;
- ireq->rcv_wscale = tcp_opt.rcv_wscale;
ireq->sack_ok = tcp_opt.sack_ok;
ireq->wscale_ok = tcp_opt.wscale_ok;
ireq->tstamp_ok = tcp_opt.saw_tstamp;
@@ -240,17 +231,12 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
* me if there is a preferred way.
*/
{
- struct in6_addr *final_p = NULL, final;
+ struct in6_addr *final_p, final;
struct flowi fl;
memset(&fl, 0, sizeof(fl));
fl.proto = IPPROTO_TCP;
ipv6_addr_copy(&fl.fl6_dst, &ireq6->rmt_addr);
- if (np->opt && np->opt->srcrt) {
- struct rt0_hdr *rt0 = (struct rt0_hdr *) np->opt->srcrt;
- ipv6_addr_copy(&final, &fl.fl6_dst);
- ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
- final_p = &final;
- }
+ final_p = fl6_update_dst(&fl, np->opt, &final);
ipv6_addr_copy(&fl.fl6_src, &ireq6->loc_addr);
fl.oif = sk->sk_bound_dev_if;
fl.mark = sk->sk_mark;
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