tcp: Add tcp_parse_aligned_timestamp

Some duplicated code lying around. Located with my suffix tree
tool.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 18 insertions, 19 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 580f9547ddf..f79a5160729 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3442,6 +3442,22 @@ void tcp_parse_options(struct sk_buff *skb, struct tcp_options_received *opt_rx,
         }
 }
 
+static int tcp_parse_aligned_timestamp(struct tcp_sock *tp, struct tcphdr *th)
+{
+        __be32 *ptr = (__be32 *)(th + 1);
+
+        if (*ptr == htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16)
+                          | (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP)) {
+                tp->rx_opt.saw_tstamp = 1;
+                ++ptr;
+                tp->rx_opt.rcv_tsval = ntohl(*ptr);
+                ++ptr;
+                tp->rx_opt.rcv_tsecr = ntohl(*ptr);
+                return 1;
+        }
+        return 0;
+}
+
 /* Fast parse options. This hopes to only see timestamps.
  * If it is wrong it falls back on tcp_parse_options().
  */
@@ -3453,16 +3469,8 @@ static int tcp_fast_parse_options(struct sk_buff *skb, struct tcphdr *th,
                 return 0;
         } else if (tp->rx_opt.tstamp_ok &&
                    th->doff == (sizeof(struct tcphdr)>>2)+(TCPOLEN_TSTAMP_ALIGNED>>2)) {
-                __be32 *ptr = (__be32 *)(th + 1);
-                if (*ptr == htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16)
-                                  | (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP)) {
-                        tp->rx_opt.saw_tstamp = 1;
-                        ++ptr;
-                        tp->rx_opt.rcv_tsval = ntohl(*ptr);
-                        ++ptr;
-                        tp->rx_opt.rcv_tsecr = ntohl(*ptr);
+                if (tcp_parse_aligned_timestamp(tp, th))
                         return 1;
-                }
         }
         tcp_parse_options(skb, &tp->rx_opt, 1);
         return 1;
@@ -4822,19 +4830,10 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb,
 
                 /* Check timestamp */
                 if (tcp_header_len == sizeof(struct tcphdr) + TCPOLEN_TSTAMP_ALIGNED) {
-                        __be32 *ptr = (__be32 *)(th + 1);
-
                         /* No? Slow path! */
-                        if (*ptr != htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16)
-                                          | (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP))
+                        if (!tcp_parse_aligned_timestamp(tp, th))
                                 goto slow_path;
 
-                        tp->rx_opt.saw_tstamp = 1;
-                        ++ptr;
-                        tp->rx_opt.rcv_tsval = ntohl(*ptr);
-                        ++ptr;
-                        tp->rx_opt.rcv_tsecr = ntohl(*ptr);
-
                         /* If PAWS failed, check it more carefully in slow path */
                         if ((s32)(tp->rx_opt.rcv_tsval - tp->rx_opt.ts_recent) < 0)
                                 goto slow_path;