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| author | Florian Westphal <fw@strlen.de> | 2010-06-21 13:48:45 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-06-27 07:00:03 +0200 |
| commit | 172d69e63c7f1e8300d0e1c1bbd8eb0f630faa15 (patch) | |
| tree | c71118ddc86186e235a920b9529c457db5e9aae5 /net/ipv4/syncookies.c | |
| parent | syncookies: do not store rcv_wscale in tcp timestamp (diff) | |
| download | linux-172d69e63c7f1e8300d0e1c1bbd8eb0f630faa15.tar.xz linux-172d69e63c7f1e8300d0e1c1bbd8eb0f630faa15.zip | |
syncookies: add support for ECN
Allows use of ECN when syncookies are in effect by encoding ecn_ok
into the syn-ack tcp timestamp.
While at it, remove a uneeded #ifdef CONFIG_SYN_COOKIES.
With CONFIG_SYN_COOKIES=nm want_cookie is ifdef'd to 0 and gcc
removes the "if (0)".
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/syncookies.c')
| -rw-r--r-- | net/ipv4/syncookies.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c index 8896329aebd0..650cace2180d 100644 --- a/net/ipv4/syncookies.c +++ b/net/ipv4/syncookies.c @@ -19,7 +19,7 @@ #include <net/route.h> /* Timestamps: lowest bits store TCP options */ -#define TSBITS 5 +#define TSBITS 6 #define TSMASK (((__u32)1 << TSBITS) - 1) extern int sysctl_tcp_syncookies; @@ -73,6 +73,7 @@ __u32 cookie_init_timestamp(struct request_sock *req) options = ireq->wscale_ok ? ireq->snd_wscale : 0xf; options |= ireq->sack_ok << 4; + options |= ireq->ecn_ok << 5; ts = ts_now & ~TSMASK; ts |= options; @@ -226,11 +227,11 @@ static inline struct sock *get_cookie_sock(struct sock *sk, struct sk_buff *skb, * This extracts these options from the timestamp echo. * * The lowest 4 bits store snd_wscale. - * The next lsb is for sack_ok + * next 2 bits indicate SACK and ECN support. * * return false if we decode an option that should not be. */ -bool cookie_check_timestamp(struct tcp_options_received *tcp_opt) +bool cookie_check_timestamp(struct tcp_options_received *tcp_opt, bool *ecn_ok) { /* echoed timestamp, lowest bits contain options */ u32 options = tcp_opt->rcv_tsecr & TSMASK; @@ -244,6 +245,9 @@ bool cookie_check_timestamp(struct tcp_options_received *tcp_opt) return false; tcp_opt->sack_ok = (options >> 4) & 0x1; + *ecn_ok = (options >> 5) & 1; + if (*ecn_ok && !sysctl_tcp_ecn) + return false; if (tcp_opt->sack_ok && !sysctl_tcp_sack) return false; @@ -272,6 +276,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, int mss; struct rtable *rt; __u8 rcv_wscale; + bool ecn_ok; if (!sysctl_tcp_syncookies || !th->ack || th->rst) goto out; @@ -288,7 +293,7 @@ struct sock *cookie_v4_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 (!cookie_check_timestamp(&tcp_opt)) + if (!cookie_check_timestamp(&tcp_opt, &ecn_ok)) goto out; ret = NULL; @@ -305,7 +310,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, ireq->rmt_port = th->source; ireq->loc_addr = ip_hdr(skb)->daddr; ireq->rmt_addr = ip_hdr(skb)->saddr; - ireq->ecn_ok = 0; + ireq->ecn_ok = ecn_ok; ireq->snd_wscale = tcp_opt.snd_wscale; ireq->sack_ok = tcp_opt.sack_ok; ireq->wscale_ok = tcp_opt.wscale_ok; |