On Thu, Sep 05, 2024 at 07:20:42AM +0200, Claudio Jeker wrote:
> On Thu, Sep 05, 2024 at 12:38:41AM +0200, Alexander Bluhm wrote:
> > On Thu, Aug 29, 2024 at 09:15:54PM +0200, Alexander Bluhm wrote:
> > > On Wed, Aug 28, 2024 at 10:43:16PM +0200, Alexander Bluhm wrote:
> > > > 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 /pc 0xfffffd8006fd5100
> > > 
> > > Additionally we can print mbuf type and offset.  Then a UDP receive
> > > socket buffer looks like this:
> > > 
> > > ++- mbuf 0xfffffd806dcddd00, nam, off 0, len 16
> > > |+- mbuf 0xfffffd806dcddf00, dat, off 52, len 1472, pktlen 2049, clsize 2048
> > > |+- mbuf 0xfffffd806dcdd400, dat, off 44, len 577, clsize 2048
> > > |\- total chain 3, len 2065, size 4320
> > > ++- mbuf 0xfffffd806dcdde00, nam, off 0, len 16
> > > |+- mbuf 0xfffffd806dcdd800, dat, off 52, len 4, pktlen 4, clsize 2048
> > > |\- total chain 2, len 20, size 2272
> > > \-- total packets 2
> > 
> > A m->m_type >= 0 check was missing.
> 
> One could wonder why m_type is a short?
>  

The next `mh_flags' is u_short, so this saves a little bit of memory?

> > > ok?
> > 
> > Anyone?
> 
> OK claudio@
>

Also ok by me.

> > 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	29 Aug 2024 17:57:18 -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	29 Aug 2024 17:57:18 -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 -r1.291 uipc_mbuf.c
> > --- sys/kern/uipc_mbuf.c	29 Aug 2024 10:44:40 -0000	1.291
> > +++ sys/kern/uipc_mbuf.c	29 Aug 2024 19:18:25 -0000
> > @@ -1533,6 +1533,80 @@ m_print(void *v,
> >  
> >  	}
> >  }
> > +
> > +const char *m_types[MT_NTYPES] = {
> > +	"fre",
> > +	"dat",
> > +	"hdr",
> > +	"nam",
> > +	"opt",
> > +	"ftb",
> > +	"ctl",
> > +	"oob",
> > +};
> > +
> > +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) {
> > +		const char *type;
> > +
> > +		chain++;
> > +		len += m->m_len;
> > +		size += M_SIZE(m);
> > +		type = (m->m_type >= 0 && m->m_type < MT_NTYPES) ?
> > +		    m_types[m->m_type] : "???";
> > +		(*pr)("%s mbuf %p, %s, off %zd, len %u", indent, m, type,
> > +		    m->m_data - M_DATABUF(m), 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);
> > +		(*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;
> > +			size += M_SIZE(n);
> > +		}
> > +		(*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
> > 
> 
> -- 
> :wq Claudio
>