[dpdk-dev,1/3] pcap: utilize underlying real interface properties

  Hi Tero,

Just a few comments on one of your patches - see inline comments below. Interesting features btw.

Nico.

-- 
Nicolás Pernas Maradei


On 27 February 2015 at 13:43:14, dev-request@dpdk.org (dev-request@dpdk.org) wrote:

Message: 5 
Date: Fri, 27 Feb 2015 15:42:38 +0200 
From: Tero Aho <tero.aho@coriant.com> 
To: <dev@dpdk.org> 
Subject: [dpdk-dev] [PATCH 1/3] pcap: utilize underlying real 
interface	properties 
Message-ID: <1425044560-23397-2-git-send-email-tero.aho@coriant.com> 
Content-Type: text/plain 

These changes set pcap interface mac address to the real underlying 
interface address instead of the default one. Also real interface link 
status, speed and duplex are reported when eth_link_update is called 
for the pcap interface. 

Signed-off-by: Tero Aho <tero.aho@coriant.com> 
--- 
lib/librte_pmd_pcap/rte_eth_pcap.c | 51 +++++++++++++++++++++++++++++++++++--- 
1 file changed, 47 insertions(+), 4 deletions(-) 

+ cmd.duplex ? ETH_LINK_FULL_DUPLEX : ETH_LINK_HALF_DUPLEX; 
+ } 
+ } 
return 0; 
} 

@@ -736,11 +763,24 @@ rte_pmd_init_internals(const char *name, const unsigned nb_rx_queues, 
(*internals)->nb_rx_queues = nb_rx_queues; 
(*internals)->nb_tx_queues = nb_tx_queues; 

- if (pair == NULL) 
+ if (pair == NULL) { 
(*internals)->if_index = 0; 
- else 
+ } else { 
+ /* use real inteface mac addr, save name and fd for eth_link_update */ 
(*internals)->if_index = if_nametoindex(pair->value); 
- 
+ (*internals)->if_name = strdup(pair->value); 
+ (*internals)->if_fd = socket(AF_INET, SOCK_DGRAM, 0); 
I see you are using a socket and ioctl calls to get the info you need from the interface. I’m not a big fan of opening a socket at this point just to get some parameters of the NIC. I’d rather reading those from sysfs. Is there a reason why you’d prefer to open a socket?

These would be the files you’d need to open and read to the get the info you are looking for. 

# cat /sys/class/net/eth0/address
# cat /sys/class/net/eth0/duplex
# cat /sys/class/net/eth0/speed

In my opinion the code would be cleaner doing it this way. DPDK already manipulates sysfs in other places too. 
What do you think?


+ if ((*internals)->if_fd != -1) { 
+ struct ifreq ifr; 
+ strncpy(ifr.ifr_name, pair->value, sizeof(ifr.ifr_name)-1); 
+ ifr.ifr_name[sizeof(ifr.ifr_name)-1] = 0; 
Use snprintf() like before.


+ if (!ioctl((*internals)->if_fd, SIOCGIFHWADDR, &ifr)) { 
+ data->mac_addrs = rte_zmalloc_socket(NULL, ETHER_ADDR_LEN, 0, numa_node); 
+ if (data->mac_addrs) 
+ rte_memcpy(data->mac_addrs, ifr.ifr_addr.sa_data, ETHER_ADDR_LEN); 
+ } 
+ } 
+ } 
pci_dev->numa_node = numa_node; 

data->dev_private = *internals; 
@@ -749,7 +789,8 @@ rte_pmd_init_internals(const char *name, const unsigned nb_rx_queues, 
data->nb_rx_queues = (uint16_t)nb_rx_queues; 
data->nb_tx_queues = (uint16_t)nb_tx_queues; 
data->dev_link = pmd_link; 
- data->mac_addrs = &eth_addr; 
+ if (data->mac_addrs == NULL) 
+ data->mac_addrs = &eth_addr; 
strncpy(data->name, 
(*eth_dev)->data->name, strlen((*eth_dev)->data->name)); 

@@ -758,6 +799,8 @@ rte_pmd_init_internals(const char *name, const unsigned nb_rx_queues, 
(*eth_dev)->pci_dev = pci_dev; 
(*eth_dev)->driver = &rte_pcap_pmd; 

+ eth_link_update((*eth_dev), 0); 
+ 
return 0; 

error: if (data) 
-- 
1.9.1 


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