UDPDK

UDPDK is a minimal UDP stack based on DPDK for fast point-to-point communication between servers.
It runs completely in userspace, so that you can move your packets quickly without going through the cumbersome kernel stack.
Moreover, thanks to its POSIX-like API, porting existing applications to UDPDK is dead easy!¹

What UDPDK is:

• A transport-level network stack
• A POSIX-like implementation of UDP sockets on top of DPDK
• A framework for low-latency packet exchanging

What UDPDK is NOT:

• A complete IP stack
• A mechanism to interconnect large networks nodes
• A software running on low-end consumer NICs

¹Some features may be unsupported yet.

Table of Contents

• UDPDK
  • Requirements
  • Install Dependencies
  • Install UDPDK
  • API
  • Examples
  • How it works
  • License
  • Contributing

Requirements

In order to use UDPDK, your machines must be equipped with DPDK-enabled NICs; these are typically found in servers, not in laptops and desktop machines. The list of hardware officially supported by DPDK is available here. Specifically, UDPDK has been developed and tested on Intel X710-DA2 with igb_uio and vfio drivers; other devices may still work, possibly with minor changes to the framework.

Install Dependencies

UDPDK requires:

• DPDK 20.05
• inih (any)

They are already included in this repository as submodules, so pull them:

git submodule init
git submodule update

DPDK

DPDK is the pivotal element of UDPDK. It manages the NIC and implements Ethernet.

cd dpdk/usertools
./dpdk-setup.sh

From the menu, do the following:

1. Compile for your specific arch, usually x86_64-native-linuxapp-gcc
2. Load the vfio module
3. Configure hugepages (e.g. 1024M for each NUMA node)
4. Bind the NIC to vfio driver, specifying its PCI address

inih

inih is used for convenience to parse .ini configuration files.

cd inih
meson build
cd build
ninja

Build and install UDPDK

UDPDK builds into a static library, which eventually needs to be linked with the final application.

cd udpdk
make
sudo make install

API

The API of UDPDK closely resembles that of good old BSD sockets:

int udpdk_socket(int domain, int type, int protocol);
int udpdk_bind(int s, const struct sockaddr *addr, socklen_t addrlen);
int getsockopt(int sockfd, int level, int optname, void *optval, socklen_t *optlen);
int setsockopt(int sockfd, int level, int optname, const void *optval, socklen_t *optlen);
ssize_t udpdk_sendto(int sockfd, const void *buf, size_t len, int flags, const struct sockaddr *dest_addr, socklen_t addrlen);
ssize_t udpdk_recvfrom(int s, void *buf, size_t len, int flags, struct sockaddr *src_addr, socklen_t *addrlen);
int udpdk_close(int s);

In addition, the following methods are required for the proper setup and teardown of DPDK internals (structures and processes):

int udpdk_init(int argc, char *argv[]);
void udpdk_interrupt(int signum);
void udpdk_cleanup(void);

Note: select() is not implemented yet

Examples

The apps/ folder contains two simple examples: a ping-pong and a pkt-gen application.

How it works

UDPDK runs in two separate processes: the primary is the one containing the application logic (i.e. where syscalls are called), while the secondary (poller) continuously polls the NIC to send and receive data. The packets are exchanged between the application and the poller through shared memory, using lockless ring queues.

License

UDPDK is released under BSD 3-Clause license.

Contributing

Everyone is more than welcome to contribute to UDPDK by implementing new features, extending existing ones or simply reporting bugs/issues.