syncookies: do not store rcv_wscale in tcp timestamp

[deliverable/linux.git] / net / ipv6 / syncookies.c

diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c
index 34d1f0690d7e4f6031172fd4640da207b07c25b3..84d818cfae17fed8794f6231b8dcde31fcc457ce 100644 (file)
--- 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)
@@ -174,7 +165,7 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
        struct dst_entry *dst;
        __u8 rcv_wscale;
 
-       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 +180,8 @@ 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))
+               goto out;
 
        ret = NULL;
        req = inet6_reqsk_alloc(&tcp6_request_sock_ops);
@@ -226,7 +217,6 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
        req->retrans = 0;
        ireq->ecn_ok            = 0;
        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 +230,12 @@ 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;