From 8298c17c6c98d5beb96edbf9be046d6009cf3011 Mon Sep 17 00:00:00 2001
From: Mark Johnston <markj@FreeBSD.org>
Date: Wed, 2 Oct 2013 17:14:12 +0000
Subject: [PATCH] Add a separate translator for headers passed to the TCP
 probes in the input path. These probes get some of the fields in host order,
 whereas the output probes get them in network order, so a single translator
 isn't enough. This workaround ensures that the problem is essentially
 invisble to users: none of the probe arguments or their fields have changed.

Approved by:	re (hrs)
---
 cddl/lib/libdtrace/tcp.d | 40 +++++++++++++++++++++++++++++++++++++++-
 sys/netinet/in_kdtrace.c |  8 ++++----
 2 files changed, 43 insertions(+), 5 deletions(-)

diff --git a/cddl/lib/libdtrace/tcp.d b/cddl/lib/libdtrace/tcp.d
index 6d56eb7fca31..4204507dc3eb 100644
--- a/cddl/lib/libdtrace/tcp.d
+++ b/cddl/lib/libdtrace/tcp.d
@@ -141,6 +141,25 @@ typedef struct tcpinfo {
 	struct tcphdr *tcp_hdr;		/* raw TCP header */
 } tcpinfo_t;
 
+/*
+ * A clone of tcpinfo_t used to handle the fact that the TCP input path
+ * overwrites some fields of the TCP header with their host-order equivalents.
+ * Unfortunately, DTrace doesn't let us simply typedef a new name for struct
+ * tcpinfo and define a separate translator for it.
+ */
+typedef struct tcpinfoh {
+	uint16_t tcp_sport;		/* source port */
+	uint16_t tcp_dport;		/* destination port */
+	uint32_t tcp_seq;		/* sequence number */
+	uint32_t tcp_ack;		/* acknowledgment number */
+	uint8_t tcp_offset;		/* data offset, in bytes */
+	uint8_t tcp_flags;		/* flags */
+	uint16_t tcp_window;		/* window size */
+	uint16_t tcp_checksum;		/* checksum */
+	uint16_t tcp_urgent;		/* urgent data pointer */
+	struct tcphdr *tcp_hdr;		/* raw TCP header */
+} tcpinfoh_t;
+
 #pragma D binding "1.0" translator
 translator csinfo_t < struct tcpcb *p > {
 	cs_addr =	NULL;
@@ -180,7 +199,7 @@ translator tcpsinfo_t < struct tcpcb *p > {
 	tcps_sack_snxt =	p == NULL ? 0  : p->sack_newdata;
 	tcps_rto =		p == NULL ? -1  : p->t_rxtcur / 1000; /* XXX */
 	tcps_mss =		p == NULL ? -1  : p->t_maxseg;
-	tcps_retransmit =	-1; /* XXX */
+	tcps_retransmit =	p == NULL ? -1 : p->t_rxtshift > 0 ? 1 : 0;
 };
 
 #pragma D binding "1.0" translator
@@ -197,6 +216,25 @@ translator tcpinfo_t < struct tcphdr *p > {
 	tcp_hdr =	(struct tcphdr *)p;
 };
 
+/*
+ * This translator differs from the one for tcpinfo_t in that the sequence
+ * number, acknowledgement number, window size and urgent pointer are already
+ * in host order and thus don't need to be converted.
+ */
+#pragma D binding "1.0" translator
+translator tcpinfoh_t < struct tcphdr *p > {
+	tcp_sport =	p == NULL ? 0  : ntohs(p->th_sport);
+	tcp_dport =	p == NULL ? 0  : ntohs(p->th_dport);
+	tcp_seq =	p == NULL ? -1 : p->th_seq;
+	tcp_ack =	p == NULL ? -1 : p->th_ack;
+	tcp_offset =	p == NULL ? -1 : (p->th_off >> 2);
+	tcp_flags =	p == NULL ? 0  : p->th_flags;
+	tcp_window =	p == NULL ? 0  : (p->th_win);
+	tcp_checksum =	p == NULL ? 0  : ntohs(p->th_sum);
+	tcp_urgent =	p == NULL ? 0  : p->th_urp;
+	tcp_hdr =	(struct tcphdr *)p;
+};
+
 #pragma D binding "1.0" translator
 translator tcplsinfo_t < int s > {
 	tcps_state =	s;
diff --git a/sys/netinet/in_kdtrace.c b/sys/netinet/in_kdtrace.c
index 85a5a4ead495..fc39e4396dea 100644
--- a/sys/netinet/in_kdtrace.c
+++ b/sys/netinet/in_kdtrace.c
@@ -60,7 +60,7 @@ SDT_PROBE_DEFINE5_XLATE(tcp, , , accept_established, accept-established,
     "struct tcpcb *", "csinfo_t *",
     "uint8_t *", "ipinfo_t *",
     "struct tcpcb *", "tcpsinfo_t *" ,
-    "struct tcphdr *", "tcpinfo_t *");
+    "struct tcphdr *", "tcpinfoh_t *");
 
 SDT_PROBE_DEFINE5_XLATE(tcp, , , accept_refused, accept-refused,
     "void *", "pktinfo_t *",
@@ -74,14 +74,14 @@ SDT_PROBE_DEFINE5_XLATE(tcp, , , connect_established, connect-established,
     "struct tcpcb *", "csinfo_t *",
     "uint8_t *", "ipinfo_t *",
     "struct tcpcb *", "tcpsinfo_t *" ,
-    "struct tcphdr *", "tcpinfo_t *");
+    "struct tcphdr *", "tcpinfoh_t *");
 
 SDT_PROBE_DEFINE5_XLATE(tcp, , , connect_refused, connect-refused,
     "void *", "pktinfo_t *",
     "struct tcpcb *", "csinfo_t *",
     "uint8_t *", "ipinfo_t *",
     "struct tcpcb *", "tcpsinfo_t *" ,
-    "struct tcphdr *", "tcpinfo_t *");
+    "struct tcphdr *", "tcpinfoh_t *");
 
 SDT_PROBE_DEFINE5_XLATE(tcp, , , connect_request, connect-request,
     "void *", "pktinfo_t *",
@@ -95,7 +95,7 @@ SDT_PROBE_DEFINE5_XLATE(tcp, , , receive, receive,
     "struct tcpcb *", "csinfo_t *",
     "uint8_t *", "ipinfo_t *",
     "struct tcpcb *", "tcpsinfo_t *" ,
-    "struct tcphdr *", "tcpinfo_t *");
+    "struct tcphdr *", "tcpinfoh_t *");
 
 SDT_PROBE_DEFINE5_XLATE(tcp, , , send, send,
     "void *", "pktinfo_t *",