From 57ec39a5b3e6fd23ee8c34937cfe3e6ba83be6ef Mon Sep 17 00:00:00 2001
From: Alexander Bluhm <bluhm@cvs.openbsd.org>
Date: Thu, 5 Sep 2024 08:52:28 +0000
Subject: In ddb(4) print mbuf chain and packet list.

For debugging hardware offloading, DMA requirements, bounce buffers,
and performance optimizations, knowing the memory layout of mbuf
content helps.
Implement /c and /p modifiers in ddb show mbuf.  It traverses the
pointer m_next for mbuf chain or m_nextpkt for packet list.  Show
mbuf type, data offset, mbuf length, packet length, cluster size,
and total number of elements, length and size.

OK claudio@ mvs@
---
 sys/ddb/db_command.c   | 12 ++++++++++--
 sys/ddb/db_interface.h |  4 +++-
 2 files changed, 13 insertions(+), 3 deletions(-)

(limited to 'sys/ddb')

diff --git a/sys/ddb/db_command.c b/sys/ddb/db_command.c
index 562053d112a..1e129c2e03c 100644
--- a/sys/ddb/db_command.c
+++ b/sys/ddb/db_command.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: db_command.c,v 1.101 2024/05/13 01:15:50 jsg Exp $	*/
+/*	$OpenBSD: db_command.c,v 1.102 2024/09/05 08:52:27 bluhm Exp $	*/
 /*	$NetBSD: db_command.c,v 1.20 1996/03/30 22:30:05 christos Exp $	*/
 
 /*
@@ -340,7 +340,15 @@ db_malloc_print_cmd(db_expr_t addr, int have_addr, db_expr_t count, char *modif)
 void
 db_mbuf_print_cmd(db_expr_t addr, int have_addr, db_expr_t count, char *modif)
 {
-	m_print((void *)addr, db_printf);
+	if ((modif[0] == 'c' && modif[1] == 'p') ||
+	    (modif[0] == 'p' && modif[1] == 'c'))
+		m_print_packet((void *)addr, 1, db_printf);
+	else if (modif[0] == 'c')
+		m_print_chain((void *)addr, 0, db_printf);
+	else if (modif[0] == 'p')
+		m_print_packet((void *)addr, 0, db_printf);
+	else
+		m_print((void *)addr, db_printf);
 }
 
 void
diff --git a/sys/ddb/db_interface.h b/sys/ddb/db_interface.h
index cccec9ed69c..bdde7ae345f 100644
--- a/sys/ddb/db_interface.h
+++ b/sys/ddb/db_interface.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: db_interface.h,v 1.27 2024/02/03 18:51:58 beck Exp $	*/
+/*	$OpenBSD: db_interface.h,v 1.28 2024/09/05 08:52:27 bluhm Exp $	*/
 /*	$NetBSD: db_interface.h,v 1.1 1996/02/05 01:57:03 christos Exp $	*/
 
 /*
@@ -61,6 +61,8 @@ void db_show_all_pools(db_expr_t, int, db_expr_t, char *);
 
 /* kern/uipc_mbuf.c */
 void m_print(void *, int (*)(const char *, ...));
+void m_print_chain(void *, int, int (*)(const char *, ...));
+void m_print_packet(void *, int, int (*)(const char *, ...));
 
 /* kern/uipc_socket.c */
 void so_print(void *, int (*)(const char *, ...));
-- 
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