kkumar-fk’s gists

kkumar-fk / client.c

Last active July 23, 2019 04:32

Program to benchmark client

	#include <stdio.h>
	#include <stdlib.h>
	#include <unistd.h>
	#include <strings.h>
	#include <sys/wait.h>
	#include <netdb.h>

	void create_children(int nprocs, int parent_pid)
	{
	while (nprocs-- > 0) {

kkumar-fk / server.c

Last active July 23, 2019 04:27

Server program to benchmark so_reuseport

	#include <stdio.h>
	#include <stdlib.h>
	#include <unistd.h>
	#include <sys/wait.h>
	#include <netdb.h>

	void create_children(int nprocs, int parent_pid)
	{
	while (nprocs-- > 0) {
	if (getpid() == parent_pid && fork() < 0)

kkumar-fk / result_of_command_execution

Created July 23, 2019 03:46

Output of

	# Server is listening on port #45000
	$ ss -tan \| grep :45000
	LISTEN 0 1 10.20.1.1:45000 :

	# A client connects to the server using it's source port 54762. A new
	# socket is created and is seen in ESTABLISHED state, along with the
	# earlier LISTEN socket.
	$ ss -tan \| grep :45000
	LISTEN 0 1 10.20.1.1:45000 :
	ESTAB 0 0 10.20.1.1:45000 10.20.1.100:54762

kkumar-fk / hashinfo_ds.c

Last active July 23, 2019 04:26

inet hash info

	#define LHTABLE_SIZE 32 /* Yes, really, this is all you need */

	struct inet_hashinfo {
	/* Hash table for fully established sockets */
	struct inet_ehash_bucket *ehash;
	/* Hash table for LISTEN sockets */
	struct inet_listen_hashbucket listening_hash[LHTABLE_SIZE];
	};

	struct inet_hashinfo tcp_hashinfo;

kkumar-fk / code1.c

Last active July 23, 2019 04:28

code chunk

	struct sock *__inet_lookup_skb(tcp_hashinfo, skb, src_port, dst_port)
	{
	/* Get the IPv4 header to know the source and destination IP's */
	const struct iphdr *iph = ip_hdr(skb);

	/*
	* Look up the incoming skb in tcp_hashinfo using the
	* [ Source-IP:Port, Destination-IP:Port ] tuple.
	*/
	return __inet_lookup(tcp_hashinfo, skb, iph->saddr, src_port, iph->daddr, dst_port);

kkumar-fk / code2.c

Last active July 23, 2019 04:25

code blob

	struct sock *__inet_lookup(tcp_hashinfo, skb, src_addr, src_port, dst_addr, dst_port)
	{
	/* Convert dest_port# from network to host byte order */
	u16 hnum = ntohs(dst_port);

	/* First look for an established socket ... */
	sk = __inet_lookup_established(tcp_hashinfo, src_addr, src_port, dst_addr, hnum);
	if (sk)
	return sk;

kkumar-fk / code3.c

Last active July 23, 2019 04:30

code blob

	struct sock *__inet_lookup_listener(tcp_hashinfo, skb, src_addr, src_port, dst_addr, dst_port)
	{
	/*
	* Use the destination port# to calculate a hash table slot# of the listen socket.
	* inet_lhashfn() returns a number between 0 and INET_LHTABLE_SIZE-1 (both
	* inclusive).
	*/
	unsigned int hash = inet_lhashfn(dst_port);

	/* Use this hash slot# to index the global LISTEN hash table */

kkumar-fk / code4.c

Last active July 24, 2019 03:03

code blob

	struct sock reuseport_select_sock(struct sock sk, unsigned int phash)
	{
	/* Get control block of sockets in this SO_REUSEPORT group */
	struct sock_reuseport *reuse = sk->sk_reuseport_cb;

	/* Get count of sockets in the group */
	int num_socks = reuse->num_socks;

	/* Calculate value between 0 and 'num_socks-1' (both inclusive) */
	unsigned int index = reciprocal_scale(phash, num_socks);

kkumar-fk / code5.c

Last active July 23, 2019 04:22

code blob

	struct sock_reuseport {
	u16 max_socks; /* Allocated size of socks[] array */
	u16 num_socks; /* #Elements in socks[] */
	struct sock socks[0]; / All sockets added to this group */
	};

kkumar-fk / code6.c

Last active July 23, 2019 04:33

code blob

	static int inet_reuseport_add_sock(struct sock *new_sk)
	{
	/* First check if another identical LISTEN socket, prev_sk,
	* exists. ... Then do the following:
	*/
	if (prev_sk) {
	/*
	* Not the first listener - do the following:
	* - Grow prev_sk->sk_reuseport_cb structure if required.
	* - Save new_sk socket pointer in prev_sk's socks[].

Krishna Kumar kkumar-fk