From: "Varghese, Vipin" <vipin.varghese@intel.com>
To: "Wiles, Keith" <keith.wiles@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
"Yigit, Ferruh" <ferruh.yigit@intel.com>,
"ophirmu@mellanox.com" <ophirmu@mellanox.com>,
"thomas@monjalon.net" <thomas@monjalon.net>,
"olgas@mellanox.com" <olgas@mellanox.com>
Subject: Re: [dpdk-dev] [PATCH v3] net/tap: perform proto field update for tun only
Date: Wed, 23 May 2018 04:33:12 +0000 [thread overview]
Message-ID: <4C9E0AB70F954A408CC4ADDBF0F8FA7D4D1F87F3@BGSMSX101.gar.corp.intel.com> (raw)
In-Reply-To: <DDAF44F1-BBC3-412F-B185-9B595DDB28DB@intel.com>
HI Keith,
Thanks for pointing out, please find my answer and update below
<Snipped>
> > + /*
> > + * TUN and TAP are created with IFF_NO_PI disabled.
> > + * For TUN PMD this mandatory as fields are used by
> > + * Kernel tun.c to determine whether its IP or non IP
> > + * packets.
> > + *
> > + * The logic fetches the first byte of data from mbuf
> > + * then compares whether its v4 or v6. If first byte
> > + * is 4 or 6, then protocol field is updated.
> > + */
> > + char *buff_data = rte_pktmbuf_mtod(seg, void *);
> > + j = (*buff_data & 0xf0);
> > + pi.proto = (j == 0x40) ? 0x0008 :
> > (j == 0x60) ? 0xdd86 : 0x00;
>
> Warning Will Robinson: Magic numbers :-)
>
> Can we use the correct values here ETHERTYPE_IPV6 and ETHERTYPE_IP and
> then use htons() on the values please.
Earlier I refrained from doing this assuming htnos comparison is done for each packet leading to extra cycles. So updated the comments with explanation for logic explanation and readability.
But I am ok to in co-operate the idea of using MACRO with htnos. I have used ETHER_TYPE_IPv4 and ETHER_TYPE_IPv6 which does not require extra include. The changes are available in v4 version.
>
> > + }
<Snipped>
next prev parent reply other threads:[~2018-05-23 4:33 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-14 4:53 [dpdk-dev] [PATCH] " Vipin Varghese
2018-05-14 22:27 ` Wiles, Keith
2018-05-15 9:08 ` Varghese, Vipin
2018-05-15 14:49 ` [dpdk-dev] [PATCH v2] " Vipin Varghese
2018-05-15 12:31 ` Wiles, Keith
2018-05-15 22:28 ` Ophir Munk
2018-05-22 6:33 ` Varghese, Vipin
2018-05-22 11:05 ` Varghese, Vipin
2018-05-22 13:55 ` Wiles, Keith
2018-05-22 10:47 ` [dpdk-dev] [PATCH v3] " Vipin Varghese
2018-05-22 13:53 ` Wiles, Keith
2018-05-23 4:33 ` Varghese, Vipin [this message]
2018-05-22 15:04 ` Ophir Munk
2018-05-23 4:37 ` Varghese, Vipin
2018-05-22 22:04 ` [dpdk-dev] [PATCH v4] " Ferruh Yigit
2018-05-22 22:06 ` Ferruh Yigit
2018-05-22 22:09 ` [dpdk-dev] [PATCH v5] net/tap: fix proto field for tun Ferruh Yigit
2018-05-22 22:19 ` Ferruh Yigit
2018-05-22 22:25 ` Ferruh Yigit
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