[PATCH] domain_codec: optimize call to dname_enc

Martin Lewis martin.lewis.x84 at gmail.com
Thu Jun 11 18:12:53 UTC 2020


Hi,
Yes, looks good :)

Martin

On Wed, 10 Jun 2020 at 10:21, Denys Vlasenko <vda.linux at googlemail.com>
wrote:

> Thanks. I addressed this a bit differently. Looks good now?
>
> On Tue, Jun 9, 2020 at 4:55 PM Martin Lewis <martin.lewis.x84 at gmail.com>
> wrote:
> >
> > The only call to dname_enc is with cstr = NULL, so most of dname_enc's
> logic is not used.
> > Therefore, we can directly call convert_dname and shrink the binary size.
> >
> > function                                             old     new   delta
> > convert_dname                                          -     143    +143
> > attach_option                                        463     493     +30
> > dname_enc                                            445       -    -445
> >
> ------------------------------------------------------------------------------
> > (add/remove: 1/1 grow/shrink: 1/0 up/down: 173/-445)         Total: -272
> > bytes
> >    text    data     bss     dec     hex filename
> >  993252   16923    1872 1012047   f714f busybox_old
> >  992980   16923    1872 1011775   f703f busybox_unstripped
> >
> > Signed-off-by: Martin Lewis <martin.lewis.x84 at gmail.com>
> > ---
> >  networking/udhcp/common.c       | 6 +++++-
> >  networking/udhcp/common.h       | 1 +
> >  networking/udhcp/domain_codec.c | 2 +-
> >  3 files changed, 7 insertions(+), 2 deletions(-)
> >
> > diff --git a/networking/udhcp/common.c b/networking/udhcp/common.c
> > index 9ec752dfc..f609bcfdb 100644
> > --- a/networking/udhcp/common.c
> > +++ b/networking/udhcp/common.c
> > @@ -431,7 +431,11 @@ static NOINLINE void attach_option(
> >  #if ENABLE_FEATURE_UDHCP_RFC3397
> >         if ((optflag->flags & OPTION_TYPE_MASK) == OPTION_DNS_STRING) {
> >                 /* reuse buffer and length for RFC1035-formatted string
> */
> > -               allocated = buffer = (char *)dname_enc(NULL, 0, buffer,
> &length);
> > +               allocated = buffer = (char *)convert_dname(buffer);
> > +               if (buffer == NULL)
> > +                       length = 0;
> > +               else
> > +                       length = strlen(buffer) + 1; /* including NUL */
> >         }
> >  #endif
> >
> > diff --git a/networking/udhcp/common.h b/networking/udhcp/common.h
> > index 60255eefa..7aeeb5152 100644
> > --- a/networking/udhcp/common.h
> > +++ b/networking/udhcp/common.h
> > @@ -219,6 +219,7 @@ void udhcp_add_simple_option(struct dhcp_packet
> *packet, uint8_t code, uint32_t
> >  #if ENABLE_FEATURE_UDHCP_RFC3397 || ENABLE_FEATURE_UDHCPC6_RFC3646 ||
> ENABLE_FEATURE_UDHCPC6_RFC4704
> >  char *dname_dec(const uint8_t *cstr, int clen, const char *pre)
> FAST_FUNC;
> >  uint8_t *dname_enc(const uint8_t *cstr, int clen, const char *src, int
> *retlen) FAST_FUNC;
> > +uint8_t *convert_dname(const char *src);
> >  #endif
> >  struct option_set *udhcp_find_option(struct option_set *opt_list,
> uint8_t code) FAST_FUNC;
> >
> > diff --git a/networking/udhcp/domain_codec.c
> b/networking/udhcp/domain_codec.c
> > index b7a3a5353..b5df48d87 100644
> > --- a/networking/udhcp/domain_codec.c
> > +++ b/networking/udhcp/domain_codec.c
> > @@ -113,7 +113,7 @@ char* FAST_FUNC dname_dec(const uint8_t *cstr, int
> clen, const char *pre)
> >   * RFC1035 encoding "\003foo\004blah\003com\000". Return allocated
> string, or
> >   * NULL if an error occurs.
> >   */
> > -static uint8_t *convert_dname(const char *src)
> > +uint8_t *convert_dname(const char *src)
> >  {
> >         uint8_t c, *res, *lenptr, *dst;
> >         int len;
> > --
> > 2.11.0
> >
> > _______________________________________________
> > busybox mailing list
> > busybox at busybox.net
> > http://lists.busybox.net/mailman/listinfo/busybox
>
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