On Thu, May 24, 2018 at 05:22:37PM -0700, William Tu wrote:
> On Thu, May 24, 2018 at 2:16 PM, Ben Pfaff <[email protected]> wrote:
> > On Thu, May 24, 2018 at 12:08:31PM -0700, William Tu wrote:
> >> On Thu, May 24, 2018 at 10:20 AM, Ben Pfaff <[email protected]> wrote:
> >> > On Thu, May 24, 2018 at 05:36:10AM -0700, William Tu wrote:
> >> >> On Wed, May 23, 2018 at 7:13 PM, Darrell Ball <[email protected]> wrote:
> >> >> > The struct erspan_metadata is updated to replace the 'version'
> >> >> > placeholder with the erspan base hdr.  Also, the erspan
> >> >> > index is defined explicitly as ovs_16aligned_be32 to mirror
> >> >> > its encoding.
> >> >> > Changes to odp_util result from updating the erspan index
> >> >> > type.
> >> >> >
> >> >> > CC: William Tu <[email protected]>
> >> >> > Fixes: 068794b43f0e ("erspan: Add flow-based erspan options")
> >> >> > Signed-off-by: Darrell Ball <[email protected]>
> >> >> > ---
> >> >> >  lib/odp-util.c | 36 ++++++++++++++++++++----------------
> >> >> >  lib/packets.h  |  6 +++---
> >> >> >  2 files changed, 23 insertions(+), 19 deletions(-)
> >> >> >
> >> >> > diff --git a/lib/odp-util.c b/lib/odp-util.c
> >> >> > index 105ac80..767281f 100644
> >> >> > --- a/lib/odp-util.c
> >> >> > +++ b/lib/odp-util.c
> >> >> > @@ -2786,9 +2786,9 @@ odp_tun_key_from_attr__(const struct nlattr 
> >> >> > *attr, bool is_mask,
> >> >> >
> >> >> >              memcpy(&opts, nl_attr_get(a), attr_len);
> >> >> >
> >> >> > -            tun->erspan_ver = opts.version;
> >> >> > +            tun->erspan_ver = opts.bh.ver;
> >> >> >              if (tun->erspan_ver == 1) {
> >> >> > -                tun->erspan_idx = ntohl(opts.u.index);
> >> >> > +                tun->erspan_idx = 
> >> >> > ntohl(get_16aligned_be32(&opts.u.index));
> >> >> >              } else if (tun->erspan_ver == 2) {
> >> >> >                  tun->erspan_dir = opts.u.md2.dir;
> >> >> >                  tun->erspan_hwid = get_hwid(&opts.u.md2);
> >> >> > @@ -2890,10 +2890,11 @@ tun_key_to_attr(struct ofpbuf *a, const 
> >> >> > struct flow_tnl *tun_key,
> >> >> >          !strcmp(tnl_type, "ip6erspan")) &&
> >> >> >          (tun_key->erspan_ver == 1 || tun_key->erspan_ver == 2)) {
> >> >> >          struct erspan_metadata opts;
> >> >> > +        memset(&opts, 0, sizeof opts);
> >> >> >
> >> >> > -        opts.version = tun_key->erspan_ver;
> >> >> > -        if (opts.version == 1) {
> >> >> > -            opts.u.index = htonl(tun_key->erspan_idx);
> >> >> > +        opts.bh.ver = tun_key->erspan_ver;
> >> >> > +        if (opts.bh.ver == 1) {
> >> >> > +            put_16aligned_be32(&opts.u.index, 
> >> >> > htonl(tun_key->erspan_idx));
> >> >> >          } else {
> >> >> >              opts.u.md2.dir = tun_key->erspan_dir;
> >> >> >              set_hwid(&opts.u.md2, tun_key->erspan_hwid);
> >> >> > @@ -3368,22 +3369,23 @@ format_odp_tun_erspan_opt(const struct nlattr 
> >> >> > *attr,
> >> >> >      opts = nl_attr_get(attr);
> >> >> >      mask = mask_attr ? nl_attr_get(mask_attr) : NULL;
> >> >> >
> >> >> > -    ver = (uint8_t)opts->version;
> >> >> > +    ver = opts->bh.ver;
> >> >> >      if (mask) {
> >> >> > -        ver_ma = (uint8_t)mask->version;
> >> >> > +        ver_ma = mask->bh.ver;
> >> >> >      }
> >> >> >
> >> >> >      format_u8u(ds, "ver", ver, mask ? &ver_ma : NULL, verbose);
> >> >> >
> >> >> > -    if (opts->version == 1) {
> >> >> > +    if (opts->bh.ver == 1) {
> >> >> >          if (mask) {
> >> >> >              ds_put_format(ds, "idx=%#"PRIx32"/%#"PRIx32",",
> >> >> > -                          ntohl(opts->u.index),
> >> >> > -                          ntohl(mask->u.index));
> >> >> > +                          ntohl(get_16aligned_be32(&opts->u.index)),
> >> >> > +                          ntohl(get_16aligned_be32(&mask->u.index)));
> >> >> >          } else {
> >> >> > -            ds_put_format(ds, "idx=%#"PRIx32",", 
> >> >> > ntohl(opts->u.index));
> >> >> > +            ds_put_format(ds, "idx=%#"PRIx32",",
> >> >> > +                          ntohl(get_16aligned_be32(&opts->u.index)));
> >> >> >          }
> >> >> > -    } else if (opts->version == 2) {
> >> >> > +    } else if (opts->bh.ver == 2) {
> >> >> >          dir = opts->u.md2.dir;
> >> >> >          hwid = opts->u.md2.hwid;
> >> >> >          if (mask) {
> >> >> > @@ -4859,10 +4861,11 @@ scan_erspan_metadata(const char *s,
> >> >> >
> >> >> >          if (!strncmp(s, ")", 1)) {
> >> >> >              s += 1;
> >> >> > -            key->version = ver;
> >> >> > -            key->u.index = htonl(idx);
> >> >> > +            memset(&key->bh, 0, sizeof key->bh);
> >> >> > +            key->bh.ver = ver;
> >> >> > +            put_16aligned_be32(&key->u.index, htonl(idx));
> >> >> >              if (mask) {
> >> >> > -                mask->u.index = htonl(idx_mask);
> >> >> > +                put_16aligned_be32(&mask->u.index, htonl(idx_mask));
> >> >> >              }
> >> >> >          }
> >> >> >          return s - s_base;
> >> >> > @@ -4882,7 +4885,8 @@ scan_erspan_metadata(const char *s,
> >> >> >
> >> >> >          if (!strncmp(s, ")", 1)) {
> >> >> >              s += 1;
> >> >> > -            key->version = ver;
> >> >> > +            memset(&key->bh, 0, sizeof key->bh);
> >> >> > +            key->bh.ver = ver;
> >> >> >              key->u.md2.hwid = hwid;
> >> >> >              key->u.md2.dir = dir;
> >> >> >              if (mask) {
> >> >> > diff --git a/lib/packets.h b/lib/packets.h
> >> >> > index 7645a9d..5c013a3 100644
> >> >> > --- a/lib/packets.h
> >> >> > +++ b/lib/packets.h
> >> >> > @@ -1312,10 +1312,10 @@ struct erspan_md2 {
> >> >> >  };
> >> >> >
> >> >> >  struct erspan_metadata {
> >> >> > -    int version;
> >> >> > +    struct erspan_base_hdr bh;
> >> >> >      union {
> >> >> > -        ovs_be32 index;         /* Version 1 (type II)*/
> >> >> > -        struct erspan_md2 md2;  /* Version 2 (type III) */
> >> >> > +        ovs_16aligned_be32 index;  /* Version 1 (type II). */
> >> >> > +        struct erspan_md2 md2;     /* Version 2 (type III). */
> >> >> >      } u;
> >> >> >  };
> >> >> >
> >> >> Thanks for the patch.
> >> >>
> >> >> We shouldn't change this header since struct erspan_metadata is exposed
> >> >> from kernel's UAPI header.  (see include/uapi/linux/erspan.h).
> >> >> OVS kernel module expects this binary format.
> >> >
> >> > We often use different data structures in userspace and the kernel.
> >> > This only changes the userspace one.
> >> >
> >> > It's a bad idea to use "int" for wire formats because its size can vary
> >> > among platforms (although the Linux kernel does rely on it being 32
> >> > bits, we don't make the same assumption in our userspace).
> >> >
> >>
> >> the 'int version' here is not wire format. It is to determine version 1 or 
> >> 2
> >> so that the metadata mode tunnel device knows to whether use
> >> ovs_be32 index or,
> >> struct erspan_md2 md2 (which are wire format)
> >>
> >> > It's a bad idea to use "ovs_be32" in packet formats, in userspace,
> >> > because packets aren't always aligned on 32-bit boundaries.
> >>
> >> I see. Then I think we should do:
> >> @@ -1314,7 +1314,7 @@ struct erspan_md2 {
> >>  struct erspan_metadata {
> >>      int version;
> >>      union {
> >> -        ovs_be32 index;         /* Version 1 (type II)*/
> >> +        ovs_16aligned_be32 index;         /* Version 1 (type II)*/
> >>          struct erspan_md2 md2;  /* Version 2 (type III) */
> >>      } u;
> >>  };
> >
> > OK, now I understand what's going on.  This is only used to define the
> > format of the OVS_TUNNEL_KEY_ATTR_ERSPAN_OPTS attribute.  Since it's not
> > a wire format at all, we don't need to use ovs_16aligned_be32 either,
> > and an "int" is fine too.
> >
> > Since erspan_metadata is part of the kernel ABI, which is exposed via
> > Netlink, it should normally be defined by including a kernel header
> > rather than in packets.h, which normally just defines wire formats for
> > things.  Can we arrange for that to happen?
> >
> 
> Sure.
> 
> > Thanks,
> >
> > Ben.
> >
> > Also, I guess that we could just use the data in-place:
> >
> Yes, thanks.
> I will submit a separate patch to fix this.

Thanks.
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