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-rw-r--r--net/ipv6/syncookies.c39
1 files changed, 15 insertions, 24 deletions
diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c
index 9fcb3ec7c838..70d330f8c990 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];
27#define COOKIEBITS 24 /* Upper bits store count */ 27#define COOKIEBITS 24 /* Upper bits store count */
28#define COOKIEMASK (((__u32)1 << COOKIEBITS) - 1) 28#define COOKIEMASK (((__u32)1 << COOKIEBITS) - 1)
29 29
30/* 30/* Table must be sorted. */
31 * This table has to be sorted and terminated with (__u16)-1.
32 * XXX generate a better table.
33 * Unresolved Issues: HIPPI with a 64k MSS is not well supported.
34 *
35 * Taken directly from ipv4 implementation.
36 * Should this list be modified for ipv6 use or is it close enough?
37 * rfc 2460 8.3 suggests mss values 20 bytes less than ipv4 counterpart
38 */
39static __u16 const msstab[] = { 31static __u16 const msstab[] = {
40 64 - 1, 32 64,
41 256 - 1, 33 512,
42 512 - 1, 34 536,
43 536 - 1, 35 1280 - 60,
44 1024 - 1, 36 1480 - 60,
45 1440 - 1, 37 1500 - 60,
46 1460 - 1, 38 4460 - 60,
47 4312 - 1, 39 9000 - 60,
48 (__u16)-1
49}; 40};
50/* The number doesn't include the -1 terminator */
51#define NUM_MSS (ARRAY_SIZE(msstab) - 1)
52 41
53/* 42/*
54 * This (misnamed) value is the age of syncookie which is permitted. 43 * 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)
134 123
135 tcp_synq_overflow(sk); 124 tcp_synq_overflow(sk);
136 125
137 for (mssind = 0; mss > msstab[mssind + 1]; mssind++) 126 for (mssind = ARRAY_SIZE(msstab) - 1; mssind ; mssind--)
138 ; 127 if (mss >= msstab[mssind])
139 *mssp = msstab[mssind] + 1; 128 break;
129
130 *mssp = msstab[mssind];
140 131
141 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_SYNCOOKIESSENT); 132 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_SYNCOOKIESSENT);
142 133
@@ -154,7 +145,7 @@ static inline int cookie_check(struct sk_buff *skb, __u32 cookie)
154 th->source, th->dest, seq, 145 th->source, th->dest, seq,
155 jiffies / (HZ * 60), COUNTER_TRIES); 146 jiffies / (HZ * 60), COUNTER_TRIES);
156 147
157 return mssind < NUM_MSS ? msstab[mssind] + 1 : 0; 148 return mssind < ARRAY_SIZE(msstab) ? msstab[mssind] : 0;
158} 149}
159 150
160struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb) 151struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)