kkumar-fk

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

#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

# 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

#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

#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) {