Re: [dpdk-dev] [PATCH v2] net/tap: perform proto field update for tun only

[Ophir Munk <ophirmu@mellanox.com>]

Hi,
I am adding my review although this patch has already been acked.
Please find some comments inline. Otherwise it looks OK.

Regards,
Ophir

> -----Original Message-----
> From: Vipin Varghese [mailto:vipin.varghese@intel.com]
> Sent: Tuesday, May 15, 2018 5:50 PM
> To: dev@dpdk.org; keith.wiles@intel.com; ferruh.yigit@intel.com; Ophir
> Munk <ophirmu@mellanox.com>
> Cc: Vipin Varghese <vipin.varghese@intel.com>
> Subject: [PATCH v2] net/tap: perform proto field update for tun only
> 
> The TX function is shared between TAP and TUN PMD. Checking TUN-TAP
> type field will ensure the TAP PMD will always have protocol field as 0.
> 
> Signed-off-by: Vipin Varghese <vipin.varghese@intel.com>
> Suggested-by: Ferruh Yigit <ferruh.yigit@intel.com>
> ---
> 
> Changes in V2:
> updated in comment wording - Keith Wiles remove debug print from tx code
> - Keith Wiles
> ---
>  drivers/net/tap/rte_eth_tap.c | 48 ++++++++++++++++++++++++++-----------
> ------
>  drivers/net/tap/rte_eth_tap.h | 10 +++++++++
>  2 files changed, 39 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
> index ea6d899..fafd557 100644
> --- a/drivers/net/tap/rte_eth_tap.c
> +++ b/drivers/net/tap/rte_eth_tap.c
> @@ -115,7 +115,8 @@ tun_alloc(struct pmd_internals *pmd)
>  	 * Do not set IFF_NO_PI as packet information header will be needed
>  	 * to check if a received packet has been truncated.
>  	 */
> -	ifr.ifr_flags = (tap_type) ? IFF_TAP : IFF_TUN | IFF_POINTOPOINT;
> +	ifr.ifr_flags = (pmd->type == ETH_TUNTAP_TYPE_TAP) ?
> +			IFF_TAP : IFF_TUN | IFF_POINTOPOINT;
>  	snprintf(ifr.ifr_name, IFNAMSIZ, "%s", pmd->name);
> 
>  	TAP_LOG(DEBUG, "ifr_name '%s'", ifr.ifr_name); @@ -502,20
> +503,22 @@ pmd_tx_burst(void *queue, struct rte_mbuf **bufs, uint16_t
> nb_pkts)
>  		if (rte_pktmbuf_pkt_len(mbuf) > max_size)
>  			break;
> 
> -		/*
> -		 * 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.
> -		 * compares whether its v4 or v6. If none matches default
> -		 * value 0x00 is taken for protocol field.
> -		 */
> -		char *buff_data = rte_pktmbuf_mtod(seg, void *);
> -		j = (*buff_data & 0xf0);
> -		pi.proto = (j == 0x40) ? 0x0008 :
> -				(j == 0x60) ? 0xdd86 : 0x00;
> +		if (txq->type == ETH_TUNTAP_TYPE_TUN) {
> +			/*
> +			 * 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;
> +		}
> 
>  		iovecs[0].iov_base = &pi;
>  		iovecs[0].iov_len = sizeof(pi);
> @@ -1052,6 +1055,9 @@ tap_setup_queue(struct rte_eth_dev *dev,
>  	tx->mtu = &dev->data->mtu;
>  	rx->rxmode = &dev->data->dev_conf.rxmode;
> 
> +	tx->type = pmd->type;
> +	rx->type = pmd->type;

It seems there is no usage for rx->type in TAP code. Therefore - can you please remove rx->type assignment?
> +
>  	return *fd;
>  }
> 
> @@ -1386,6 +1392,7 @@ eth_dev_tap_create(struct rte_vdev_device
> *vdev, char *tap_name,
>  	pmd = dev->data->dev_private;
>  	pmd->dev = dev;
>  	snprintf(pmd->name, sizeof(pmd->name), "%s", tap_name);
> +	pmd->type = ETH_TUNTAP_TYPE_UNKNOWN;
> 
>  	pmd->ioctl_sock = socket(AF_INET, SOCK_DGRAM, 0);
>  	if (pmd->ioctl_sock == -1) {
> @@ -1421,7 +1428,9 @@ eth_dev_tap_create(struct rte_vdev_device
> *vdev, char *tap_name,
>  		pmd->txq[i].fd = -1;
>  	}
> 
> -	if (tap_type) {
> +	pmd->type = (tap_type) ? ETH_TUNTAP_TYPE_TAP :
> ETH_TUNTAP_TYPE_TUN;

1. It seem you are using 'tap_type' as a global static variable to pass a value to eth_dev_tap_create().
Can you please pass this value by adding a parameter to eth_dev_tap_create() call and remove the global static variable?
2. You are using tap_type with values 0 and 1 which are converted to enums ETH_TUNTAP_TYPE_TUN and ETH_TUNTAP_TYPE_TAP respectively. Can you please always just use the enums (avoiding the conversion)?

> +
> +	if (pmd->type == ETH_TUNTAP_TYPE_TAP) {
>  		if (is_zero_ether_addr(mac_addr))
>  			eth_random_addr((uint8_t *)&pmd->eth_addr);
>  		else
> @@ -1440,7 +1449,7 @@ eth_dev_tap_create(struct rte_vdev_device
> *vdev, char *tap_name,
>  	if (tap_ioctl(pmd, SIOCSIFMTU, &ifr, 1, LOCAL_AND_REMOTE) < 0)
>  		goto error_exit;
> 
> -	if (tap_type) {
> +	if (pmd->type == ETH_TUNTAP_TYPE_TAP) {
>  		memset(&ifr, 0, sizeof(struct ifreq));
>  		ifr.ifr_hwaddr.sa_family = AF_LOCAL;
>  		rte_memcpy(ifr.ifr_hwaddr.sa_data, &pmd->eth_addr, @@ -
> 1812,7 +1821,9 @@ rte_pmd_tap_remove(struct rte_vdev_device *dev)
>  	struct pmd_internals *internals;
>  	int i;
> 
> -	TAP_LOG(DEBUG, "Closing TUN/TAP Ethernet device on numa %u",
> +	internals = eth_dev->data->dev_private;
> +	TAP_LOG(DEBUG, "Closing %s Ethernet device on numa %u",
> +		(internals->type == ETH_TUNTAP_TYPE_TAP) ? "TAP" :
> "TUN",
>  		rte_socket_id());
> 
>  	/* find the ethdev entry */
> @@ -1820,7 +1831,6 @@ rte_pmd_tap_remove(struct rte_vdev_device
> *dev)
>  	if (!eth_dev)
>  		return 0;
> 
> -	internals = eth_dev->data->dev_private;
>  	if (internals->nlsk_fd) {
>  		tap_flow_flush(eth_dev, NULL);
>  		tap_flow_implicit_flush(internals, NULL); diff --git
> a/drivers/net/tap/rte_eth_tap.h b/drivers/net/tap/rte_eth_tap.h index
> 67c9d4b..8b0da5a 100644
> --- a/drivers/net/tap/rte_eth_tap.h
> +++ b/drivers/net/tap/rte_eth_tap.h
> @@ -23,6 +23,13 @@
>  #define RTE_PMD_TAP_MAX_QUEUES	1
>  #endif
> 
> +enum rte_tuntap_type {
> +	ETH_TUNTAP_TYPE_UNKNOWN,
> +	ETH_TUNTAP_TYPE_TUN,
> +	ETH_TUNTAP_TYPE_TAP,
> +	ETH_TUNTAP_TYPE_MAX,
> +};
> +
>  struct pkt_stats {
>  	uint64_t opackets;              /* Number of output packets */
>  	uint64_t ipackets;              /* Number of input packets */
> @@ -38,6 +45,7 @@ struct rx_queue {
>  	uint32_t trigger_seen;          /* Last seen Rx trigger value */
>  	uint16_t in_port;               /* Port ID */
>  	int fd;
> +	int type;			  /* Type field - TUN|TAP */

In seems there is no usage for 'type' field from rx_queue struct in the code. If so - can you please remove it?

>  	struct pkt_stats stats;         /* Stats for this RX queue */
>  	uint16_t nb_rx_desc;            /* max number of mbufs available */
>  	struct rte_eth_rxmode *rxmode;  /* RX features */ @@ -48,6 +56,7
> @@ struct rx_queue {
> 
>  struct tx_queue {
>  	int fd;
> +	int type;			  /* Type field - TUN|TAP */

Please use spaces (like all other fields in this struct) instead of tabs, so all fields look aligned.

>  	uint16_t *mtu;                  /* Pointer to MTU from dev_data */
>  	uint16_t csum:1;                /* Enable checksum offloading */
>  	struct pkt_stats stats;         /* Stats for this TX queue */
> @@ -57,6 +66,7 @@ struct pmd_internals {
>  	struct rte_eth_dev *dev;          /* Ethernet device. */
>  	char remote_iface[RTE_ETH_NAME_MAX_LEN]; /* Remote
> netdevice name */
>  	char name[RTE_ETH_NAME_MAX_LEN];  /* Internal Tap device
> name */
> +	int type;			  /* Type field - TUN|TAP */

Same comment here about replacing tabs with spaces

>  	struct ether_addr eth_addr;       /* Mac address of the device port */
>  	struct ifreq remote_initial_flags;   /* Remote netdevice flags on init
> */
>  	int remote_if_index;              /* remote netdevice IF_INDEX */
> --
> 2.7.4