net-tcp: Fast Open base

This patch impelements the common code for both the client and server.

1. TCP Fast Open option processing. Since Fast Open does not have an
   option number assigned by IANA yet, it shares the experiment option
   code 254 by implementing draft-ietf-tcpm-experimental-options
   with a 16 bits magic number 0xF989. This enables global experiments
   without clashing the scarce(2) experimental options available for TCP.

   When the draft status becomes standard (maybe), the client should
   switch to the new option number assigned while the server supports
   both numbers for transistion.

2. The new sysctl tcp_fastopen

3. A place holder init function

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 1888169e07c72bb13a24ed1b3a018bf570ec2cb3..12948f54383958ed3ca60edfd31dea6088e6bb10 100644 (file)
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -243,6 +243,16 @@ static inline unsigned int tcp_optlen(const struct sk_buff *skb)
        return (tcp_hdr(skb)->doff - 5) * 4;
 }
 
+/* TCP Fast Open */
+#define TCP_FASTOPEN_COOKIE_MIN        4       /* Min Fast Open Cookie size in bytes */
+#define TCP_FASTOPEN_COOKIE_MAX        16      /* Max Fast Open Cookie size in bytes */
+
+/* TCP Fast Open Cookie as stored in memory */
+struct tcp_fastopen_cookie {
+       s8      len;
+       u8      val[TCP_FASTOPEN_COOKIE_MAX];
+};
+
 /* This defines a selective acknowledgement block. */
 struct tcp_sack_block_wire {
        __be32  start_seq;

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 85c5090bfe25abef6ee2f4ba88d3c10fe3fa1cca..5aed3718fde86c6b8348c745d0932973b00ac547 100644 (file)
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -170,6 +170,11 @@ extern void tcp_time_wait(struct sock *sk, int state, int timeo);
 #define TCPOPT_TIMESTAMP       8       /* Better RTT estimations/PAWS */
 #define TCPOPT_MD5SIG          19      /* MD5 Signature (RFC2385) */
 #define TCPOPT_COOKIE          253     /* Cookie extension (experimental) */
+#define TCPOPT_EXP             254     /* Experimental */
+/* Magic number to be after the option value for sharing TCP
+ * experimental options. See draft-ietf-tcpm-experimental-options-00.txt
+ */
+#define TCPOPT_FASTOPEN_MAGIC  0xF989
 
 /*
  *     TCP option lengths
@@ -180,6 +185,7 @@ 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_EXP_FASTOPEN_BASE  4
 #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)
@@ -222,6 +228,7 @@ extern int sysctl_tcp_retries1;
 extern int sysctl_tcp_retries2;
 extern int sysctl_tcp_orphan_retries;
 extern int sysctl_tcp_syncookies;
+extern int sysctl_tcp_fastopen;
 extern int sysctl_tcp_retrans_collapse;
 extern int sysctl_tcp_stdurg;
 extern int sysctl_tcp_rfc1337;
@@ -418,7 +425,7 @@ extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
                       size_t len, int nonblock, int flags, int *addr_len);
 extern void tcp_parse_options(const struct sk_buff *skb,
                              struct tcp_options_received *opt_rx, const u8 **hvpp,
-                             int estab);
+                             int estab, struct tcp_fastopen_cookie *foc);
 extern const u8 *tcp_parse_md5sig_option(const struct tcphdr *th);
 
 /*

diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
index a677d804e53ef17d9a0114cad1bbdf601951f9a9..ae2ccf2890e438147bac5d3791f0f6927f720536 100644 (file)
--- a/net/ipv4/Makefile
+++ b/net/ipv4/Makefile
@@ -7,7 +7,7 @@ obj-y     := route.o inetpeer.o protocol.o \
             ip_output.o ip_sockglue.o inet_hashtables.o \
             inet_timewait_sock.o inet_connection_sock.o \
             tcp.o tcp_input.o tcp_output.o tcp_timer.o tcp_ipv4.o \
-            tcp_minisocks.o tcp_cong.o tcp_metrics.o \
+            tcp_minisocks.o tcp_cong.o tcp_metrics.o tcp_fastopen.o \
             datagram.o raw.o udp.o udplite.o \
             arp.o icmp.o devinet.o af_inet.o  igmp.o \
             fib_frontend.o fib_semantics.o fib_trie.o \

diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index eab2a7fb15d10cf7e3d9ce563b465f0e389ec559..650e1528e1e669a7828ab94bb4a5fa4bf65c1186 100644 (file)
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -293,7 +293,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
 
        /* check for timestamp cookie support */
        memset(&tcp_opt, 0, sizeof(tcp_opt));
-       tcp_parse_options(skb, &tcp_opt, &hash_location, 0);
+       tcp_parse_options(skb, &tcp_opt, &hash_location, 0, NULL);
 
        if (!cookie_check_timestamp(&tcp_opt, &ecn_ok))
                goto out;

diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 3f6a1e762e9c69ab75f9f61850f6a5b2b288fc17..5840c3255721d8dafa923f86aea0c065c149d16b 100644 (file)
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -366,6 +366,13 @@ static struct ctl_table ipv4_table[] = {
                .proc_handler   = proc_dointvec
        },
 #endif
+       {
+               .procname       = "tcp_fastopen",
+               .data           = &sysctl_tcp_fastopen,
+               .maxlen         = sizeof(int),
+               .mode           = 0644,
+               .proc_handler   = proc_dointvec,
+       },
        {
                .procname       = "tcp_tw_recycle",
                .data           = &tcp_death_row.sysctl_tw_recycle,

diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c
new file mode 100644 (file)
index 0000000..a7f729c
--- /dev/null
+++ b/net/ipv4/tcp_fastopen.c
@@ -0,0 +1,11 @@
+#include <linux/init.h>
+#include <linux/kernel.h>
+
+int sysctl_tcp_fastopen;
+
+static int __init tcp_fastopen_init(void)
+{
+       return 0;
+}
+
+late_initcall(tcp_fastopen_init);

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index fdd49f1b7a521852ea1a26679563bf7e62032cfa..a06bb8959e7e847333ac3a947eab095a5b61c956 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3732,7 +3732,8 @@ old_ack:
  * the fast version below fails.
  */
 void tcp_parse_options(const struct sk_buff *skb, struct tcp_options_received *opt_rx,
-                      const u8 **hvpp, int estab)
+                      const u8 **hvpp, int estab,
+                      struct tcp_fastopen_cookie *foc)
 {
        const unsigned char *ptr;
        const struct tcphdr *th = tcp_hdr(skb);
@@ -3839,8 +3840,25 @@ void tcp_parse_options(const struct sk_buff *skb, struct tcp_options_received *o
                                        break;
                                }
                                break;
-                       }
 
+                       case TCPOPT_EXP:
+                               /* Fast Open option shares code 254 using a
+                                * 16 bits magic number. It's valid only in
+                                * SYN or SYN-ACK with an even size.
+                                */
+                               if (opsize < TCPOLEN_EXP_FASTOPEN_BASE ||
+                                   get_unaligned_be16(ptr) != TCPOPT_FASTOPEN_MAGIC ||
+                                   foc == NULL || !th->syn || (opsize & 1))
+                                       break;
+                               foc->len = opsize - TCPOLEN_EXP_FASTOPEN_BASE;
+                               if (foc->len >= TCP_FASTOPEN_COOKIE_MIN &&
+                                   foc->len <= TCP_FASTOPEN_COOKIE_MAX)
+                                       memcpy(foc->val, ptr + 2, foc->len);
+                               else if (foc->len != 0)
+                                       foc->len = -1;
+                               break;
+
+                       }
                        ptr += opsize-2;
                        length -= opsize;
                }
@@ -3882,7 +3900,7 @@ static bool tcp_fast_parse_options(const struct sk_buff *skb,
                if (tcp_parse_aligned_timestamp(tp, th))
                        return true;
        }
-       tcp_parse_options(skb, &tp->rx_opt, hvpp, 1);
+       tcp_parse_options(skb, &tp->rx_opt, hvpp, 1, NULL);
        return true;
 }
 
@@ -5637,7 +5655,7 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
        struct tcp_cookie_values *cvp = tp->cookie_values;
        int saved_clamp = tp->rx_opt.mss_clamp;
 
-       tcp_parse_options(skb, &tp->rx_opt, &hash_location, 0);
+       tcp_parse_options(skb, &tp->rx_opt, &hash_location, 0, NULL);
 
        if (th->ack) {
                /* rfc793:

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index d7d2fa50f07fedd9c0def65f5f49d208bf3195fa..01aa77a9702019355691696a59b569a857b03074 100644 (file)
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1307,7 +1307,7 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
        tcp_clear_options(&tmp_opt);
        tmp_opt.mss_clamp = TCP_MSS_DEFAULT;
        tmp_opt.user_mss  = tp->rx_opt.user_mss;
-       tcp_parse_options(skb, &tmp_opt, &hash_location, 0);
+       tcp_parse_options(skb, &tmp_opt, &hash_location, 0, NULL);
 
        if (tmp_opt.cookie_plus > 0 &&
            tmp_opt.saw_tstamp &&

diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index c66f2ede160e78c4dc48fe27d0d156f9a7a85105..5912ac3fd240f022b4850baeb78d1dc33b383d3f 100644 (file)
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -97,7 +97,7 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb,
 
        tmp_opt.saw_tstamp = 0;
        if (th->doff > (sizeof(*th) >> 2) && tcptw->tw_ts_recent_stamp) {
-               tcp_parse_options(skb, &tmp_opt, &hash_location, 0);
+               tcp_parse_options(skb, &tmp_opt, &hash_location, 0, NULL);
 
                if (tmp_opt.saw_tstamp) {
                        tmp_opt.ts_recent       = tcptw->tw_ts_recent;
@@ -534,7 +534,7 @@ struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb,
 
        tmp_opt.saw_tstamp = 0;
        if (th->doff > (sizeof(struct tcphdr)>>2)) {
-               tcp_parse_options(skb, &tmp_opt, &hash_location, 0);
+               tcp_parse_options(skb, &tmp_opt, &hash_location, 0, NULL);
 
                if (tmp_opt.saw_tstamp) {
                        tmp_opt.ts_recent = req->ts_recent;

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 15a7c7bc3e58f733ec1c8a8f66be59733e38d682..4849be76ccd646dc5a517a1089956aeb59dd44e5 100644 (file)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -385,15 +385,17 @@ static inline bool tcp_urg_mode(const struct tcp_sock *tp)
 #define OPTION_MD5             (1 << 2)
 #define OPTION_WSCALE          (1 << 3)
 #define OPTION_COOKIE_EXTENSION        (1 << 4)
+#define OPTION_FAST_OPEN_COOKIE        (1 << 8)
 
 struct tcp_out_options {
-       u8 options;             /* bit field of OPTION_* */
+       u16 options;            /* bit field of OPTION_* */
+       u16 mss;                /* 0 to disable */
        u8 ws;                  /* window scale, 0 to disable */
        u8 num_sack_blocks;     /* number of SACK blocks to include */
        u8 hash_size;           /* bytes in hash_location */
-       u16 mss;                /* 0 to disable */
-       __u32 tsval, tsecr;     /* need to include OPTION_TS */
        __u8 *hash_location;    /* temporary pointer, overloaded */
+       __u32 tsval, tsecr;     /* need to include OPTION_TS */
+       struct tcp_fastopen_cookie *fastopen_cookie;    /* Fast open cookie */
 };
 
 /* The sysctl int routines are generic, so check consistency here.
@@ -442,7 +444,7 @@ static u8 tcp_cookie_size_check(u8 desired)
 static void tcp_options_write(__be32 *ptr, struct tcp_sock *tp,
                              struct tcp_out_options *opts)
 {
-       u8 options = opts->options;     /* mungable copy */
+       u16 options = opts->options;    /* mungable copy */
 
        /* Having both authentication and cookies for security is redundant,
         * and there's certainly not enough room.  Instead, the cookie-less
@@ -564,6 +566,21 @@ static void tcp_options_write(__be32 *ptr, struct tcp_sock *tp,
 
                tp->rx_opt.dsack = 0;
        }
+
+       if (unlikely(OPTION_FAST_OPEN_COOKIE & options)) {
+               struct tcp_fastopen_cookie *foc = opts->fastopen_cookie;
+
+               *ptr++ = htonl((TCPOPT_EXP << 24) |
+                              ((TCPOLEN_EXP_FASTOPEN_BASE + foc->len) << 16) |
+                              TCPOPT_FASTOPEN_MAGIC);
+
+               memcpy(ptr, foc->val, foc->len);
+               if ((foc->len & 3) == 2) {
+                       u8 *align = ((u8 *)ptr) + foc->len;
+                       align[0] = align[1] = TCPOPT_NOP;
+               }
+               ptr += (foc->len + 3) >> 2;
+       }
 }
 
 /* Compute TCP options for SYN packets. This is not the final

diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c
index 7bf3cc427c28c63f71b8495be54b2138bfbb3359..bb46061c813a45c1ef859f5c60c2c5e45773ed29 100644 (file)
--- a/net/ipv6/syncookies.c
+++ b/net/ipv6/syncookies.c
@@ -177,7 +177,7 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
 
        /* check for timestamp cookie support */
        memset(&tcp_opt, 0, sizeof(tcp_opt));
-       tcp_parse_options(skb, &tcp_opt, &hash_location, 0);
+       tcp_parse_options(skb, &tcp_opt, &hash_location, 0, NULL);
 
        if (!cookie_check_timestamp(&tcp_opt, &ecn_ok))
                goto out;

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index c9dabdd832d7b726b42ae7699f6e98d72154589c..0302ec3fecfc01830903e17593a82e1dd0a814e9 100644 (file)
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1033,7 +1033,7 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
        tcp_clear_options(&tmp_opt);
        tmp_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
        tmp_opt.user_mss = tp->rx_opt.user_mss;
-       tcp_parse_options(skb, &tmp_opt, &hash_location, 0);
+       tcp_parse_options(skb, &tmp_opt, &hash_location, 0, NULL);
 
        if (tmp_opt.cookie_plus > 0 &&
            tmp_opt.saw_tstamp &&