[PATCH] app/testpmd: fix flex item link parsing

[Maayan Kashani]

Thanks Stephen, 
I'll send v2 with required change.

Regards,
Maayan Kashani

> -----Original Message-----
> From: Stephen Hemminger <stephen at networkplumber.org>
> Sent: Friday, 14 November 2025 0:38
> To: Maayan Kashani <mkashani at nvidia.com>
> Cc: dev at dpdk.org; Raslan Darawsheh <rasland at nvidia.com>;
> stable at dpdk.org; Aman Singh <aman.deep.singh at intel.com>; Slava
> Ovsiienko <viacheslavo at nvidia.com>; Gregory Etelson
> <getelson at nvidia.com>
> Subject: Re: [PATCH] app/testpmd: fix flex item link parsing
> 
> External email: Use caution opening links or attachments
> 
> 
> On Thu, 13 Nov 2025 22:17:25 +0200
> Maayan Kashani <mkashani at nvidia.com> wrote:
> 
> > The flex_link_item_parse function was using
> > FLEX_MAX_FLOW_PATTERN_LENGTH for all memcpy operations regardless
> of
> > the actual flow item type. This could lead to copying incorrect amounts of
> data.
> >
> > This patch adds a switch statement to determine the correct size based
> > on the actual flow item type (IPv4, IPv6, UDP, TCP) and uses that size
> > for the memcpy operations on spec, mask, and last fields.
> >
> > Also adds validation to reject unsupported item types.
> >
> > Fixes: 59f3a8acbcdb ("app/testpmd: add flex item commands")
> > Cc: stable at dpdk.org
> >
> > Signed-off-by: Maayan Kashani <mkashani at nvidia.com>
> > ---
> >  app/test-pmd/cmd_flex_item.c | 10 +++++++---
> >  1 file changed, 7 insertions(+), 3 deletions(-)
> >
> > diff --git a/app/test-pmd/cmd_flex_item.c
> > b/app/test-pmd/cmd_flex_item.c index e6e1cefeb3d..ec19ab63e75 100644
> > --- a/app/test-pmd/cmd_flex_item.c
> > +++ b/app/test-pmd/cmd_flex_item.c
> > @@ -134,6 +134,7 @@ flex_link_item_parse(const char *src, struct
> rte_flow_item *item)
> >       struct rte_flow_attr *attr;
> >       struct rte_flow_item *pattern;
> >       struct rte_flow_action *actions;
> > +     size_t sz = 0;
> >
> >       sprintf(flow_rule,
> >               "flow create 0 pattern %s / end actions drop / end",
> > src); @@ -143,21 +144,24 @@ flex_link_item_parse(const char *src, struct
> rte_flow_item *item)
> >       if (ret)
> >               return ret;
> >       item->type = pattern->type;
> > +     ret = rte_flow_conv(RTE_FLOW_CONV_OP_ITEM_MASK, NULL, 0, item,
> NULL);
> > +     if (ret > 0)
> > +             sz = ret;
> 
> You don't really need a temporary variable sz, can't you just use the return
> value directly or are you concerned about signed/unsigned mismatch.
> If concerned about signed/unsigned mismatch warnings then would need
> cast on the assignment to sz.