This patch is a prerequisite for the following change.
For non-BPF SYN Cookie, inet_rsk(req)->ecn_ok is initialised with
tcp_opt->rcv_tsecr & TS_OPT_ECN. OTOH, we will initialise it
differently for BPF SYN Cookie.
Then, inet_rsk(req)->ecn_ok is updated with net->ipv4.sysctl_tcp_ecn
or dst_feature(dst, RTAX_FEATURE_ECN).
Now cookie_ecn_ok() is just oneliner, but TS_OPT_ECN is only available
in net/ipv4/syncookies.c. Instead of exporting the function, we move
it and TS_OPT_XXX to tcp.h.
Signed-off-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
---
include/net/tcp.h | 31 +++++++++++++++++++++++++++++--
net/ipv4/syncookies.c | 43 +++----------------------------------------
net/ipv6/syncookies.c | 4 +++-
3 files changed, 35 insertions(+), 43 deletions(-)
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 4fe19917db6c..143f47c28312 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -569,8 +569,35 @@ __u32 cookie_v4_init_sequence(const struct sk_buff *skb, __u16 *mss);
u64 cookie_init_timestamp(struct request_sock *req, u64 now);
bool cookie_timestamp_decode(const struct net *net,
struct tcp_options_received *opt);
-bool cookie_ecn_ok(const struct tcp_options_received *opt,
- const struct net *net, const struct dst_entry *dst);
+
+/* TCP Timestamp: 6 lowest bits of timestamp sent in the cookie SYN-ACK
+ * stores TCP options:
+ *
+ * MSB LSB
+ * | 31 ... 6 | 5 | 4 | 3 2 1 0 |
+ * | Timestamp | ECN | SACK | WScale |
+ *
+ * When we receive a valid cookie-ACK, we look at the echoed tsval (if
+ * any) to figure out which TCP options we should use for the rebuilt
+ * connection.
+ *
+ * A WScale setting of '0xf' (which is an invalid scaling value)
+ * means that original syn did not include the TCP window scaling option.
+ */
+#define TS_OPT_WSCALE_MASK 0xf
+#define TS_OPT_SACK BIT(4)
+#define TS_OPT_ECN BIT(5)
+/* There is no TS_OPT_TIMESTAMP:
+ * if ACK contains timestamp option, we already know it was
+ * requested/supported by the syn/synack exchange.
+ */
+#define TSBITS 6
+#define TSMASK (((__u32)1 << TSBITS) - 1)
+
+static inline bool cookie_ecn_ok(const struct tcp_options_received *tcp_opt)
+{
+ return tcp_opt->rcv_tsecr & TS_OPT_ECN;
+}
/* From net/ipv6/syncookies.c */
int __cookie_v6_check(const struct ipv6hdr *iph, const struct tcphdr *th,
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index f78566991e08..ff979cc314da 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -19,30 +19,6 @@ static siphash_aligned_key_t syncookie_secret[2];
#define COOKIEBITS 24 /* Upper bits store count */
#define COOKIEMASK (((__u32)1 << COOKIEBITS) - 1)
-/* TCP Timestamp: 6 lowest bits of timestamp sent in the cookie SYN-ACK
- * stores TCP options:
- *
- * MSB LSB
- * | 31 ... 6 | 5 | 4 | 3 2 1 0 |
- * | Timestamp | ECN | SACK | WScale |
- *
- * When we receive a valid cookie-ACK, we look at the echoed tsval (if
- * any) to figure out which TCP options we should use for the rebuilt
- * connection.
- *
- * A WScale setting of '0xf' (which is an invalid scaling value)
- * means that original syn did not include the TCP window scaling option.
- */
-#define TS_OPT_WSCALE_MASK 0xf
-#define TS_OPT_SACK BIT(4)
-#define TS_OPT_ECN BIT(5)
-/* There is no TS_OPT_TIMESTAMP:
- * if ACK contains timestamp option, we already know it was
- * requested/supported by the syn/synack exchange.
- */
-#define TSBITS 6
-#define TSMASK (((__u32)1 << TSBITS) - 1)
-
static u32 cookie_hash(__be32 saddr, __be32 daddr, __be16 sport, __be16 dport,
u32 count, int c)
{
@@ -266,21 +242,6 @@ bool cookie_timestamp_decode(const struct net *net,
}
EXPORT_SYMBOL(cookie_timestamp_decode);
-bool cookie_ecn_ok(const struct tcp_options_received *tcp_opt,
- const struct net *net, const struct dst_entry *dst)
-{
- bool ecn_ok = tcp_opt->rcv_tsecr & TS_OPT_ECN;
-
- if (!ecn_ok)
- return false;
-
- if (READ_ONCE(net->ipv4.sysctl_tcp_ecn))
- return true;
-
- return dst_feature(dst, RTAX_FEATURE_ECN);
-}
-EXPORT_SYMBOL(cookie_ecn_ok);
-
struct request_sock *cookie_tcp_reqsk_alloc(const struct request_sock_ops *ops,
const struct tcp_request_sock_ops *af_ops,
struct sock *sk,
@@ -438,6 +399,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
goto out;
}
} else {
+ ireq->ecn_ok = cookie_ecn_ok(&tcp_opt);
treq->ts_off = tsoff;
}
@@ -498,7 +460,8 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
dst_metric(&rt->dst, RTAX_INITRWND));
ireq->rcv_wscale = rcv_wscale;
- ireq->ecn_ok = cookie_ecn_ok(&tcp_opt, net, &rt->dst);
+ ireq->ecn_ok &= READ_ONCE(net->ipv4.sysctl_tcp_ecn) ||
+ dst_feature(&rt->dst, RTAX_FEATURE_ECN);
ret = tcp_get_cookie_sock(sk, skb, req, &rt->dst);
/* ip_queue_xmit() depends on our flow being setup
diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c
index b0a7ea75a504..f4c0cb463e02 100644
--- a/net/ipv6/syncookies.c
+++ b/net/ipv6/syncookies.c
@@ -198,6 +198,7 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
goto out;
}
} else {
+ ireq->ecn_ok = cookie_ecn_ok(&tcp_opt);
treq->ts_off = tsoff;
}
@@ -272,7 +273,8 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
dst_metric(dst, RTAX_INITRWND));
ireq->rcv_wscale = rcv_wscale;
- ireq->ecn_ok = cookie_ecn_ok(&tcp_opt, net, dst);
+ ireq->ecn_ok &= READ_ONCE(net->ipv4.sysctl_tcp_ecn) ||
+ dst_feature(dst, RTAX_FEATURE_ECN);
ret = tcp_get_cookie_sock(sk, skb, req, dst);
out:
--
2.30.2
