tcp: Replace constants with #define macros
to record the state of SACK/FACK and DSACK for better readability and maintenance.
Signed-off-by: Vijay Subramanian <subramanian.vijay@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 7f59ee9..46a85c9 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -238,6 +238,11 @@
u32 end_seq;
};
+/*These are used to set the sack_ok field in struct tcp_options_received */
+#define TCP_SACK_SEEN (1 << 0) /*1 = peer is SACK capable, */
+#define TCP_FACK_ENABLED (1 << 1) /*1 = FACK is enabled locally*/
+#define TCP_DSACK_SEEN (1 << 2) /*1 = DSACK was received from peer*/
+
struct tcp_options_received {
/* PAWS/RTTM data */
long ts_recent_stamp;/* Time we stored ts_recent (for aging) */
diff --git a/include/net/tcp.h b/include/net/tcp.h
index a4f52e1..0118ea9 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -773,12 +773,12 @@
static inline int tcp_is_fack(const struct tcp_sock *tp)
{
- return tp->rx_opt.sack_ok & 2;
+ return tp->rx_opt.sack_ok & TCP_FACK_ENABLED;
}
static inline void tcp_enable_fack(struct tcp_sock *tp)
{
- tp->rx_opt.sack_ok |= 2;
+ tp->rx_opt.sack_ok |= TCP_FACK_ENABLED;
}
static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index 90f6544..51fdbb4 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -245,7 +245,7 @@
if (!sysctl_tcp_timestamps)
return false;
- tcp_opt->sack_ok = (options >> 4) & 0x1;
+ tcp_opt->sack_ok = (options & (1 << 4)) ? TCP_SACK_SEEN : 0;
*ecn_ok = (options >> 5) & 1;
if (*ecn_ok && !sysctl_tcp_ecn)
return false;
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index f131d92..2877c3e 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -865,13 +865,13 @@
/* RFC3517 uses different metric in lost marker => reset on change */
if (tcp_is_fack(tp))
tp->lost_skb_hint = NULL;
- tp->rx_opt.sack_ok &= ~2;
+ tp->rx_opt.sack_ok &= ~TCP_FACK_ENABLED;
}
/* Take a notice that peer is sending D-SACKs */
static void tcp_dsack_seen(struct tcp_sock *tp)
{
- tp->rx_opt.sack_ok |= 4;
+ tp->rx_opt.sack_ok |= TCP_DSACK_SEEN;
}
/* Initialize metrics on socket. */
@@ -3878,7 +3878,7 @@
case TCPOPT_SACK_PERM:
if (opsize == TCPOLEN_SACK_PERM && th->syn &&
!estab && sysctl_tcp_sack) {
- opt_rx->sack_ok = 1;
+ opt_rx->sack_ok = TCP_SACK_SEEN;
tcp_sack_reset(opt_rx);
}
break;