Download raw body.
ddb mbuf chains
Hi,
I want to print the layout of mbuf chains in ddb. For debugging
hardware offloading, DMA requirements and bounce buffers, I need
to know the layout of the mbuf chain by m_next and m_nextpkt pointer.
So I implemented /c and /p modifiers for ddb show mbuf.
ddb> show mbuf /c 0xfffffd8006fd5100
-+- mbuf 0xfffffd8006fd5100, len 10136, pktlen 17376, clsize 65536
+- mbuf 0xfffffd807df8f800, len 7240, pktlen 7240, clsize 8192
+- mbuf 0xfffffd8006fd5d00, len 2896, pktlen 2896, clsize 4096
\- total chain 3, len 20272, size 77824
ddb> show mbuf /pc 0xfffffd8006fd5100
++- mbuf 0xfffffd8006fd5100, len 10136, pktlen 17376, clsize 65536
|+- mbuf 0xfffffd807df8f800, len 7240, pktlen 7240, clsize 8192
|+- mbuf 0xfffffd8006fd5d00, len 2896, pktlen 2896, clsize 4096
|\- total chain 3, len 20272, size 77824
\-- total packets 1
ddb> show mbuf /p 0xfffffd8006fd5100
+-- mbuf 0xfffffd8006fd5100, chain 3, pktlen 17376, len 20272, size 77824
\-- total packets 1
ddb> show mbuf 0xfffffd8006fd5100
mbuf 0xfffffd8006fd5100
m_type: 1 m_flags: b<M_EXT,M_PKTHDR,M_EXTWR>
m_next: 0xfffffd807df8f800 m_nextpkt: 0x0
m_data: 0xfffffd8006d69c48 m_len: 10136
m_dat: 0xfffffd8006fd5120 m_pktdat: 0xfffffd8006fd5170
m_ptkhdr.ph_ifidx: 0 m_pkthdr.len: 17376
m_ptkhdr.ph_tags: 0x0 m_pkthdr.ph_tagsset: 0
m_pkthdr.ph_flowid: 0 m_pkthdr.ph_loopcnt: 0
m_pkthdr.csum_flags: 0
m_pkthdr.ether_vtag: 0 m_ptkhdr.ph_rtableid: 0
m_pkthdr.pf.statekey: 0x0 m_pkthdr.pf.inp 0x0
m_pkthdr.pf.qid: 0 m_pkthdr.pf.tag: 0
m_pkthdr.pf.flags: 0
m_pkthdr.pf.routed: 0 m_pkthdr.pf.prio: 3
m_ext.ext_buf: 0xfffffd8006d68000 m_ext.ext_size: 65536
m_ext.ext_free_fn: 0 m_ext.ext_arg: 0xffffffff828b2148
m_ext.ext_nextref: 0xfffffd8006fd5100 m_ext.ext_prevref: 0xfffffd8006fd5100
ok?
bluhm
Index: sys/ddb/db_command.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/ddb/db_command.c,v
diff -u -p -r1.101 db_command.c
--- sys/ddb/db_command.c 13 May 2024 01:15:50 -0000 1.101
+++ sys/ddb/db_command.c 28 Aug 2024 19:47:43 -0000
@@ -340,7 +340,15 @@ db_malloc_print_cmd(db_expr_t addr, int
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
Index: sys/ddb/db_interface.h
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/ddb/db_interface.h,v
diff -u -p -r1.27 db_interface.h
--- sys/ddb/db_interface.h 3 Feb 2024 18:51:58 -0000 1.27
+++ sys/ddb/db_interface.h 28 Aug 2024 19:44:28 -0000
@@ -61,6 +61,8 @@ void db_show_all_pools(db_expr_t, int, d
/* 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 *, ...));
Index: sys/kern/uipc_mbuf.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/kern/uipc_mbuf.c,v
diff -u -p -r1.290 uipc_mbuf.c
--- sys/kern/uipc_mbuf.c 5 Mar 2024 18:52:41 -0000 1.290
+++ sys/kern/uipc_mbuf.c 28 Aug 2024 20:27:48 -0000
@@ -1542,6 +1542,73 @@ m_print(void *v,
}
}
+
+void
+m_print_chain(void *v, int deep,
+ int (*pr)(const char *, ...) __attribute__((__format__(__kprintf__,1,2))))
+{
+ struct mbuf *m;
+ const char *indent = deep ? "++-" : "-+-";
+ size_t chain = 0, len = 0, size = 0;
+
+ for (m = v; m != NULL; m = m->m_next) {
+ chain++;
+ (*pr)("%s mbuf %p, len %u", indent, m, m->m_len);
+ len += m->m_len;
+ if (m->m_flags & M_PKTHDR)
+ (*pr)(", pktlen %d", m->m_pkthdr.len);
+ if (m->m_flags & M_EXT) {
+ (*pr)(", clsize %u", m->m_ext.ext_size);
+ size += m->m_ext.ext_size;
+ } else if (m->m_flags & M_PKTHDR)
+ size += MHLEN;
+ else
+ size += MLEN;
+ (*pr)("\n");
+ indent = deep ? "|+-" : " +-";
+ }
+ indent = deep ? "|\\-" : " \\-";
+ if (v != NULL) {
+ (*pr)("%s total chain %zu, len %zu, size %zu\n",
+ indent, chain, len, size);
+ }
+}
+
+void
+m_print_packet(void *v, int deep,
+ int (*pr)(const char *, ...) __attribute__((__format__(__kprintf__,1,2))))
+{
+ struct mbuf *m, *n;
+ const char *indent = "+--";
+ size_t pkts = 0;
+
+ for (m = v; m != NULL; m = m->m_nextpkt) {
+ size_t chain = 0, len = 0, size = 0;
+
+ pkts++;
+ if (deep) {
+ m_print_chain(m, deep, pr);
+ continue;
+ }
+ for (n = m; n != NULL; n = n->m_next) {
+ chain++;
+ len += n->m_len;
+ if (n->m_flags & M_EXT)
+ size += n->m_ext.ext_size;
+ else if (n->m_flags & M_PKTHDR)
+ size += MHLEN;
+ else
+ size += MLEN;
+ }
+ (*pr)("%s mbuf %p, chain %zu", indent, m, chain);
+ if (m->m_flags & M_PKTHDR)
+ (*pr)(", pktlen %d", m->m_pkthdr.len);
+ (*pr)(", len %zu, size %zu\n", len, size);
+ }
+ indent = "\\--";
+ if (v != NULL)
+ (*pr)("%s total packets %zu\n", indent, pkts);
+}
#endif
/*
Index: share/man/man4/ddb.4
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/share/man/man4/ddb.4,v
diff -u -p -r1.107 ddb.4
--- share/man/man4/ddb.4 5 Feb 2024 21:33:00 -0000 1.107
+++ share/man/man4/ddb.4 28 Aug 2024 19:51:26 -0000
@@ -658,7 +658,11 @@ If the
.Cm /f
modifier is specified, the complete map is printed.
.\" --------------------
-.It Ic show mbuf Ar addr
+.It Xo
+.Ic show mbuf
+.Op Cm /cp
+.Ar addr
+.Xc
Prints the
.Vt struct mbuf
header at
@@ -668,6 +672,13 @@ Depending on the mbuf flags
and
.Vt struct m_ext
are printed as well.
+If the
+.Cm /c
+modifier is specified, print the mbuf chain linked with the m_next
+pointer.
+.Cm /p
+does the same using m_nextpkt.
+Both can be combined.
.\" --------------------
.It Xo
.Ic show mount
ddb mbuf chains