Filtering
Filtering using pcap_setfilter is SW-based and does not utilize the filtering capabilities of the SmartNICs. Filtering using Napatech libpcap with configuration files is HW-based. It is also possible to use the ntpl tool (see DN-0449) for HW filtering after the driver has been loaded.
libpcap functions
Napatech libpcap supports all libpcap functions with a few limitations:
libpcap Function | Limitation |
---|---|
int pcap_setdirection(pcap_t *, pcap_direction_t) | Supports only PCAP_D_N, received packets. |
int pcap_set_promisc(pcap_t *, int) | Accepted, but will always run promiscuous mode. |
int pcap_set_timeout(pcap_t *, int) | Has no effect. Will always run 100 ms time-out. |
int pcap_set_tstamp_type(pcap_t *, int) | Supports only PCAP_TSTAMP_ADAPTER_UNSYNCED SmartNIC time-stamping. |
int pcap_set_buffer_size(pcap_t *, int) | Has no effect. Will always run zero-copy mode. |
Style Conventions
Bold typeface is used for names of, for instance, user interface elements and software components.
Italic typeface is used for replaceable text.
Monospaced typeface is used for code, commands and file names.
Abbreviations
BNF
Backus-Naur Form
BP
ByPass
CentOS
Community ENTerprise Operating System
CRC
Cyclic Redundancy Check
DN
Document Number
GCC
GNU Compiler Collection
Gen
GENeration
GNU
GNU’s Not Unix
HB
Host Buffer
hba
Host Buffer Allowance
http
HyperText Transfer Protocol
https
HyperText Transfer Protocol Secure
HW
HardWare
Id, ID
IDentifier
IFG
Inter-Frame Gap
libpcap
Packet CAPture LIBrary
LSB
Least Significant Bit
Min
MINimum
MSB
Most Significant Bit
NDIS
Network Driver Interface Specification
nt, NT
NapaTech
NTAPI
NapaTech Application Programming Interface
ntpl, Ntpl, NTPL
NapaTech Programming Language
Numa, NUMA
Non-Uniform Memory Access
pcap, PCAP
Packet CAPture
PCI
Peripheral Component Interconnect
PTP
Precision Time Protocol
Rev.
REVision
RHEL
Red Hat Enterprise Linux
Rx, RX
Receive
STD
STanDard
SW
SoftWare
tx, Tx, TX
Transmission/Transmit