diff options
| -rw-r--r-- | net/ipv4/syncookies.c | 35 | ||||
| -rw-r--r-- | net/ipv6/syncookies.c | 1 |
2 files changed, 14 insertions, 22 deletions
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c index 51b5662545d6..8896329aebd0 100644 --- a/net/ipv4/syncookies.c +++ b/net/ipv4/syncookies.c @@ -18,8 +18,8 @@ #include <net/tcp.h> #include <net/route.h> -/* Timestamps: lowest 9 bits store TCP options */ -#define TSBITS 9 +/* Timestamps: lowest bits store TCP options */ +#define TSBITS 5 #define TSMASK (((__u32)1 << TSBITS) - 1) extern int sysctl_tcp_syncookies; @@ -58,7 +58,7 @@ static u32 cookie_hash(__be32 saddr, __be32 daddr, __be16 sport, __be16 dport, /* * when syncookies are in effect and tcp timestamps are enabled we encode - * tcp options in the lowest 9 bits of the timestamp value that will be + * tcp options in the lower bits of the timestamp value that will be * sent in the syn-ack. * Since subsequent timestamps use the normal tcp_time_stamp value, we * must make sure that the resulting initial timestamp is <= tcp_time_stamp. @@ -70,11 +70,9 @@ __u32 cookie_init_timestamp(struct request_sock *req) u32 options = 0; ireq = inet_rsk(req); - if (ireq->wscale_ok) { - options = ireq->snd_wscale; - options |= ireq->rcv_wscale << 4; - } - options |= ireq->sack_ok << 8; + + options = ireq->wscale_ok ? ireq->snd_wscale : 0xf; + options |= ireq->sack_ok << 4; ts = ts_now & ~TSMASK; ts |= options; @@ -227,15 +225,14 @@ static inline struct sock *get_cookie_sock(struct sock *sk, struct sk_buff *skb, * additional tcp options in the timestamp. * This extracts these options from the timestamp echo. * - * The lowest 4 bits are for snd_wscale - * The next 4 lsb are for rcv_wscale + * The lowest 4 bits store snd_wscale. * The next lsb is for sack_ok * * return false if we decode an option that should not be. */ bool cookie_check_timestamp(struct tcp_options_received *tcp_opt) { - /* echoed timestamp, 9 lowest bits contain options */ + /* echoed timestamp, lowest bits contain options */ u32 options = tcp_opt->rcv_tsecr & TSMASK; if (!tcp_opt->saw_tstamp) { @@ -246,20 +243,17 @@ bool cookie_check_timestamp(struct tcp_options_received *tcp_opt) if (!sysctl_tcp_timestamps) return false; - tcp_opt->snd_wscale = options & 0xf; - options >>= 4; - tcp_opt->rcv_wscale = options & 0xf; - tcp_opt->sack_ok = (options >> 4) & 0x1; if (tcp_opt->sack_ok && !sysctl_tcp_sack) return false; - if (tcp_opt->snd_wscale || tcp_opt->rcv_wscale) { - tcp_opt->wscale_ok = 1; - return sysctl_tcp_window_scaling != 0; - } - return true; + if ((options & 0xf) == 0xf) + return true; /* no window scaling */ + + tcp_opt->wscale_ok = 1; + tcp_opt->snd_wscale = options & 0xf; + return sysctl_tcp_window_scaling != 0; } EXPORT_SYMBOL(cookie_check_timestamp); @@ -313,7 +307,6 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, ireq->rmt_addr = ip_hdr(skb)->saddr; 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; diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c index c7ee57421ece..84d818cfae17 100644 --- a/net/ipv6/syncookies.c +++ b/net/ipv6/syncookies.c @@ -217,7 +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; |
