1 files changed, 97 insertions, 34 deletions

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 03a49c703377..34f5cc24d903 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -30,6 +30,7 @@
 #include <linux/dmaengine.h>
 #include <linux/crypto.h>
 #include <linux/cryptohash.h>
+#include <linux/kref.h>
 
 #include <net/inet_connection_sock.h>
 #include <net/inet_timewait_sock.h>
@@ -62,9 +63,6 @@ extern void tcp_time_wait(struct sock *sk, int state, int timeo);
 /* Minimal accepted MSS. It is (60+60+8) - (20+20). */
 #define TCP_MIN_MSS             88U
 
-/* Minimal RCV_MSS. */
-#define TCP_MIN_RCVMSS          536U
-
 /* The least MTU to use for probing */
 #define TCP_BASE_MSS            512
 
@@ -167,6 +165,7 @@ extern void tcp_time_wait(struct sock *sk, int state, int timeo);
 #define TCPOPT_SACK             5       /* SACK Block */
 #define TCPOPT_TIMESTAMP        8       /* Better RTT estimations/PAWS */
 #define TCPOPT_MD5SIG           19      /* MD5 Signature (RFC2385) */
+#define TCPOPT_COOKIE           253     /* Cookie extension (experimental) */
 
 /*
  *     TCP option lengths
@@ -177,6 +176,10 @@ extern void tcp_time_wait(struct sock *sk, int state, int timeo);
 #define TCPOLEN_SACK_PERM      2
 #define TCPOLEN_TIMESTAMP      10
 #define TCPOLEN_MD5SIG         18
+#define TCPOLEN_COOKIE_BASE    2        /* Cookie-less header extension */
+#define TCPOLEN_COOKIE_PAIR    3        /* Cookie pair header extension */
+#define TCPOLEN_COOKIE_MIN     (TCPOLEN_COOKIE_BASE+TCP_COOKIE_MIN)
+#define TCPOLEN_COOKIE_MAX     (TCPOLEN_COOKIE_BASE+TCP_COOKIE_MAX)
 
 /* But this is what stacks really send out. */
 #define TCPOLEN_TSTAMP_ALIGNED          12
@@ -237,6 +240,7 @@ extern int sysctl_tcp_base_mss;
 extern int sysctl_tcp_workaround_signed_windows;
 extern int sysctl_tcp_slow_start_after_idle;
 extern int sysctl_tcp_max_ssthresh;
+extern int sysctl_tcp_cookie_size;
 
 extern atomic_t tcp_memory_allocated;
 extern struct percpu_counter tcp_sockets_allocated;
@@ -343,11 +347,6 @@ static inline void tcp_dec_quickack_mode(struct sock *sk,
 
 extern void tcp_enter_quickack_mode(struct sock *sk);
 
-static inline void tcp_clear_options(struct tcp_options_received *rx_opt)
-{
-        rx_opt->tstamp_ok = rx_opt->sack_ok = rx_opt->wscale_ok = rx_opt->snd_wscale = 0;
-}
-
 #define TCP_ECN_OK              1
 #define TCP_ECN_QUEUE_CWR       2
 #define TCP_ECN_DEMAND_CWR      4
@@ -359,8 +358,7 @@ TCP_ECN_create_request(struct request_sock *req, struct tcphdr *th)
                 inet_rsk(req)->ecn_ok = 1;
 }
 
-enum tcp_tw_status
-{
+enum tcp_tw_status {
         TCP_TW_SUCCESS = 0,
         TCP_TW_RST = 1,
         TCP_TW_ACK = 2,
@@ -409,6 +407,7 @@ extern int			tcp_recvmsg(struct kiocb *iocb, struct sock *sk,
 
 extern void                     tcp_parse_options(struct sk_buff *skb,
                                                   struct tcp_options_received *opt_rx,
+                                                  u8 **hvpp,
                                                   int estab);
 
 extern u8                       *tcp_parse_md5sig_option(struct tcphdr *th);
@@ -443,7 +442,8 @@ extern int			tcp_connect(struct sock *sk);
 
 extern struct sk_buff *         tcp_make_synack(struct sock *sk,
                                                 struct dst_entry *dst,
-                                                struct request_sock *req);
+                                                struct request_sock *req,
+                                                struct request_values *rvp);
 
 extern int                      tcp_disconnect(struct sock *sk, int flags);
 
@@ -1228,6 +1228,7 @@ static inline void tcp_write_queue_purge(struct sock *sk)
         while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL)
                 sk_wmem_free_skb(sk, skb);
         sk_mem_reclaim(sk);
+        tcp_clear_all_retrans_hints(tcp_sk(sk));
 }
 
 static inline struct sk_buff *tcp_write_queue_head(struct sock *sk)
@@ -1259,29 +1260,6 @@ static inline struct sk_buff *tcp_write_queue_prev(struct sock *sk, struct sk_bu
 #define tcp_for_write_queue_from_safe(skb, tmp, sk)                     \
         skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp)
 
-/* This function calculates a "timeout" which is equivalent to the timeout of a
- * TCP connection after "boundary" unsucessful, exponentially backed-off
- * retransmissions with an initial RTO of TCP_RTO_MIN.
- */
-static inline bool retransmits_timed_out(const struct sock *sk,
-                                         unsigned int boundary)
-{
-        unsigned int timeout, linear_backoff_thresh;
-
-        if (!inet_csk(sk)->icsk_retransmits)
-                return false;
-
-        linear_backoff_thresh = ilog2(TCP_RTO_MAX/TCP_RTO_MIN);
-
-        if (boundary <= linear_backoff_thresh)
-                timeout = ((2 << boundary) - 1) * TCP_RTO_MIN;
-        else
-                timeout = ((2 << linear_backoff_thresh) - 1) * TCP_RTO_MIN +
-                          (boundary - linear_backoff_thresh) * TCP_RTO_MAX;
-
-        return (tcp_time_stamp - tcp_sk(sk)->retrans_stamp) >= timeout;
-}
-
 static inline struct sk_buff *tcp_send_head(struct sock *sk)
 {
         return sk->sk_send_head;
@@ -1480,6 +1458,91 @@ struct tcp_request_sock_ops {
 #endif
 };
 
+/* Using SHA1 for now, define some constants.
+ */
+#define COOKIE_DIGEST_WORDS (SHA_DIGEST_WORDS)
+#define COOKIE_MESSAGE_WORDS (SHA_MESSAGE_BYTES / 4)
+#define COOKIE_WORKSPACE_WORDS (COOKIE_DIGEST_WORDS + COOKIE_MESSAGE_WORDS)
+
+extern int tcp_cookie_generator(u32 *bakery);
+
+/**
+ *      struct tcp_cookie_values - each socket needs extra space for the
+ *      cookies, together with (optional) space for any SYN data.
+ *
+ *      A tcp_sock contains a pointer to the current value, and this is
+ *      cloned to the tcp_timewait_sock.
+ *
+ * @cookie_pair:        variable data from the option exchange.
+ *
+ * @cookie_desired:     user specified tcpct_cookie_desired.  Zero
+ *                      indicates default (sysctl_tcp_cookie_size).
+ *                      After cookie sent, remembers size of cookie.
+ *                      Range 0, TCP_COOKIE_MIN to TCP_COOKIE_MAX.
+ *
+ * @s_data_desired:     user specified tcpct_s_data_desired.  When the
+ *                      constant payload is specified (@s_data_constant),
+ *                      holds its length instead.
+ *                      Range 0 to TCP_MSS_DESIRED.
+ *
+ * @s_data_payload:     constant data that is to be included in the
+ *                      payload of SYN or SYNACK segments when the
+ *                      cookie option is present.
+ */
+struct tcp_cookie_values {
+        struct kref     kref;
+        u8              cookie_pair[TCP_COOKIE_PAIR_SIZE];
+        u8              cookie_pair_size;
+        u8              cookie_desired;
+        u16             s_data_desired:11,
+                        s_data_constant:1,
+                        s_data_in:1,
+                        s_data_out:1,
+                        s_data_unused:2;
+        u8              s_data_payload[0];
+};
+
+static inline void tcp_cookie_values_release(struct kref *kref)
+{
+        kfree(container_of(kref, struct tcp_cookie_values, kref));
+}
+
+/* The length of constant payload data.  Note that s_data_desired is
+ * overloaded, depending on s_data_constant: either the length of constant
+ * data (returned here) or the limit on variable data.
+ */
+static inline int tcp_s_data_size(const struct tcp_sock *tp)
+{
+        return (tp->cookie_values != NULL && tp->cookie_values->s_data_constant)
+                ? tp->cookie_values->s_data_desired
+                : 0;
+}
+
+/**
+ *      struct tcp_extend_values - tcp_ipv?.c to tcp_output.c workspace.
+ *
+ *      As tcp_request_sock has already been extended in other places, the
+ *      only remaining method is to pass stack values along as function
+ *      parameters.  These parameters are not needed after sending SYNACK.
+ *
+ * @cookie_bakery:      cryptographic secret and message workspace.
+ *
+ * @cookie_plus:        bytes in authenticator/cookie option, copied from
+ *                      struct tcp_options_received (above).
+ */
+struct tcp_extend_values {
+        struct request_values           rv;
+        u32                             cookie_bakery[COOKIE_WORKSPACE_WORDS];
+        u8                              cookie_plus:6,
+                                        cookie_out_never:1,
+                                        cookie_in_always:1;
+};
+
+static inline struct tcp_extend_values *tcp_xv(struct request_values *rvp)
+{
+        return (struct tcp_extend_values *)rvp;
+}
+
 extern void tcp_v4_init(void);
 extern void tcp_init(void);