Assert the tcbinfo write lock in tcp_new_isn(), as the tcbinfo lock

protects access to the ISN state variables.

Acquire the tcbinfo write lock in tcp_isn_tick() to synchronize
timer-driven isn bumping.

Staticize internal ISN variables since they're not used outside of
tcp_subr.c.

MFC after:	2 weeks

2 files changed, 22 insertions, 8 deletions

diff --git a/sys/netinet/tcp_subr.c b/sys/netinet/tcp_subr.c
index f63cb5a..d54b6fa 100644
--- a/sys/netinet/tcp_subr.c
+++ b/sys/netinet/tcp_subr.c
@@ -1282,16 +1282,19 @@ tcp6_ctlinput(cmd, sa, d)
  * between seeding of isn_secret.  This is normally set to zero,
  * as reseeding should not be necessary.
  *
+ * Locking of the global variables isn_secret, isn_last_reseed, isn_offset,
+ * isn_offset_old, and isn_ctx is performed using the TCP pcbinfo lock.  In
+ * general, this means holding an exclusive (write) lock.
  */
 
 #define ISN_BYTES_PER_SECOND 1048576
 #define ISN_STATIC_INCREMENT 4096
 #define ISN_RANDOM_INCREMENT (4096 - 1)
 
-u_char isn_secret[32];
-int isn_last_reseed;
-u_int32_t isn_offset, isn_offset_old;
-MD5_CTX isn_ctx;
+static u_char isn_secret[32];
+static int isn_last_reseed;
+static u_int32_t isn_offset, isn_offset_old;
+static MD5_CTX isn_ctx;
 
 tcp_seq
 tcp_new_isn(tp)
@@ -1300,6 +1303,8 @@ tcp_new_isn(tp)
 	u_int32_t md5_buffer[4];
 	tcp_seq new_isn;
 
+	INP_INFO_WLOCK_ASSERT(&tcbinfo);
+
 	/* Seed if this is the first use, reseed if requested. */
 	if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) &&
 	     (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz)
@@ -1346,6 +1351,7 @@ tcp_isn_tick(xtp)
 {
 	u_int32_t projected_offset;
 
+	INP_INFO_WLOCK(&tcbinfo);
 	projected_offset = isn_offset_old + ISN_BYTES_PER_SECOND / hz;
 
 	if (projected_offset > isn_offset)
@@ -1353,6 +1359,7 @@ tcp_isn_tick(xtp)
 
 	isn_offset_old = isn_offset;
 	callout_reset(&isn_callout, 1, tcp_isn_tick, NULL);
+	INP_INFO_WUNLOCK(&tcbinfo);
 }
 
 /*
diff --git a/sys/netinet/tcp_timewait.c b/sys/netinet/tcp_timewait.c
index f63cb5a..d54b6fa 100644
--- a/sys/netinet/tcp_timewait.c
+++ b/sys/netinet/tcp_timewait.c
@@ -1282,16 +1282,19 @@ tcp6_ctlinput(cmd, sa, d)
  * between seeding of isn_secret.  This is normally set to zero,
  * as reseeding should not be necessary.
  *
+ * Locking of the global variables isn_secret, isn_last_reseed, isn_offset,
+ * isn_offset_old, and isn_ctx is performed using the TCP pcbinfo lock.  In
+ * general, this means holding an exclusive (write) lock.
  */
 
 #define ISN_BYTES_PER_SECOND 1048576
 #define ISN_STATIC_INCREMENT 4096
 #define ISN_RANDOM_INCREMENT (4096 - 1)
 
-u_char isn_secret[32];
-int isn_last_reseed;
-u_int32_t isn_offset, isn_offset_old;
-MD5_CTX isn_ctx;
+static u_char isn_secret[32];
+static int isn_last_reseed;
+static u_int32_t isn_offset, isn_offset_old;
+static MD5_CTX isn_ctx;
 
 tcp_seq
 tcp_new_isn(tp)
@@ -1300,6 +1303,8 @@ tcp_new_isn(tp)
 	u_int32_t md5_buffer[4];
 	tcp_seq new_isn;
 
+	INP_INFO_WLOCK_ASSERT(&tcbinfo);
+
 	/* Seed if this is the first use, reseed if requested. */
 	if ((isn_last_reseed == 0) || ((tcp_isn_reseed_interval > 0) &&
 	     (((u_int)isn_last_reseed + (u_int)tcp_isn_reseed_interval*hz)
@@ -1346,6 +1351,7 @@ tcp_isn_tick(xtp)
 {
 	u_int32_t projected_offset;
 
+	INP_INFO_WLOCK(&tcbinfo);
 	projected_offset = isn_offset_old + ISN_BYTES_PER_SECOND / hz;
 
 	if (projected_offset > isn_offset)
@@ -1353,6 +1359,7 @@ tcp_isn_tick(xtp)
 
 	isn_offset_old = isn_offset;
 	callout_reset(&isn_callout, 1, tcp_isn_tick, NULL);
+	INP_INFO_WUNLOCK(&tcbinfo);
 }
 
 /*