Re: [PATCH v3] app/testpmd: fix VLAN header parsing

[Thomas Monjalon <thomas@monjalon.net>]

24/03/2025 14:18, Morten Brørup:
> > From: Raslan Darawsheh [mailto:rasland@nvidia.com]
> > Sent: Monday, 24 March 2025 10.34
> > 
> > When processing VLAN or QinQ packets, an infinite loop occurred,
> > preventing the csum forward engine from proceeding and causing
> > testpmd to hang during shutdown attempts.
> > 
> > Updated the `get_ethertype_by_ptype` function to correctly parse
> > VLAN headers.
> > 
> > Fixes: 76730c7b9b5a ("app/testpmd: use packet type parsing API")
> > Cc: haijie1@huawei.com
> > 
> > Signed-off-by: Raslan Darawsheh <rasland@nvidia.com>
> > ---
> > v3: fixed wrong indentation
> >     add boundaries check for 8 VLANs at max
> > 
> > v2: update commit log
> >     fixed pointer handling to actually move the pointer
> > ---
> >  app/test-pmd/csumonly.c | 16 +++++++++++-----
> >  1 file changed, 11 insertions(+), 5 deletions(-)
> > 
> > diff --git a/app/test-pmd/csumonly.c b/app/test-pmd/csumonly.c
> > index 5b906eaa53..710967ca4d 100644
> > --- a/app/test-pmd/csumonly.c
> > +++ b/app/test-pmd/csumonly.c
> > @@ -59,6 +59,8 @@
> >  #define GRE_SUPPORTED_FIELDS	(GRE_CHECKSUM_PRESENT | GRE_KEY_PRESENT
> > |\
> >  				 GRE_SEQUENCE_PRESENT)
> > 
> > +#define MAX_VLAN_HEADERS 8
> > +
> >  /* We cannot use rte_cpu_to_be_16() on a constant in a switch/case */
> >  #if RTE_BYTE_ORDER == RTE_LITTLE_ENDIAN
> >  #define _htons(x) ((uint16_t)((((x) & 0x00ffU) << 8) | (((x) &
> > 0xff00U) >> 8)))
> > @@ -466,9 +468,10 @@ pkts_ip_csum_recalc(struct rte_mbuf **pkts_burst,
> > const uint16_t nb_pkts, uint64
> >  static uint32_t
> >  get_ethertype_by_ptype(struct rte_ether_hdr *eth_hdr, uint32_t ptype)
> >  {
> > -	struct rte_vlan_hdr *vlan_hdr;
> > +	struct rte_vlan_hdr *vlan_hdr, *max_vlans;
> >  	uint16_t ethertype;
> > 
> > +
> 
> Please omit adding an extra empty line.
> 
> >  	switch (ptype) {
> >  	case RTE_PTYPE_L3_IPV4:
> >  	case RTE_PTYPE_L3_IPV4_EXT:
> > @@ -486,10 +489,13 @@ get_ethertype_by_ptype(struct rte_ether_hdr
> > *eth_hdr, uint32_t ptype)
> >  		return _htons(RTE_ETHER_TYPE_IPV6);
> >  	default:
> >  		ethertype = eth_hdr->ether_type;
> > -		while (eth_hdr->ether_type == _htons(RTE_ETHER_TYPE_VLAN)
> > ||
> > -			eth_hdr->ether_type == _htons(RTE_ETHER_TYPE_QINQ)) {
> > -			vlan_hdr = (struct rte_vlan_hdr *)
> > -				((char *)eth_hdr + sizeof(*eth_hdr));
> > +		vlan_hdr = (struct rte_vlan_hdr *) RTE_PTR_ADD(eth_hdr,

useless type cast

> > +					offsetof(struct rte_ether_hdr,
> > ether_type));
> 
> Above line indentation with 2, not 3 TABs.
> 
> > +		max_vlans = vlan_hdr + MAX_VLAN_HEADERS;
> > +		while (((ethertype == _htons(RTE_ETHER_TYPE_VLAN) ||
> 
> Superfluous parenthesis: "while ( ((x || y)) && z)".
> 
> > +			ethertype == _htons(RTE_ETHER_TYPE_QINQ))) &&
> > +			vlan_hdr < max_vlans) {
> 
> Above two lines indentation with 2, not 1 TAB.
> 
> > +			vlan_hdr++;
> >  			ethertype = vlan_hdr->eth_proto;
> >  		}
> >  		return ethertype;
> > --
> > 2.39.5 (Apple Git-154)
> 
> With above nits fixed (can be fixed when merging),
> Reviewed-by: Morten Brørup <mb@smartsharesystems.com>

All nits fixed and applied, thanks.