/*
 * This program is in the public domain and may be used freely by anyone
 * who wants to.
 *
 * Please send bug fixes/bug reports to: Peter Eriksson <pen@lysator.liu.se>
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/user.h>
#include <sys/wait.h>
#define _KERNEL
#include <sys/file.h>
#undef _KERNEL
#include <sys/sysctl.h>

#include <stdio.h>
#include <errno.h>
#include <ctype.h>
#include <limits.h>
#include <nlist.h>
#include <pwd.h>
#include <signal.h>
#include <syslog.h>
#include <kvm.h>
#include <fcntl.h>

#include <net/if.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/tcp.h>
#include <netinet/ip_var.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>

#include <arpa/inet.h>

#include "identd.h"
#include "error.h"

struct nlist nl[] = {
#define N_TCBTABLE 0
	{"_tcbtable"},
	{""}
};

static kvm_t *kd;
static struct inpcbtable tcbtable;

int
k_open()
{
	char    errbuf[_POSIX2_LINE_MAX];

	/*
        ** Open the kernel memory device
        */
	if ((kd = kvm_openfiles(path_unix, path_kmem, NULL, O_RDONLY, errbuf)) ==
	    NULL)
		ERROR1("main: kvm_open: %s", errbuf);

	/*
        ** Extract offsets to the needed variables in the kernel
        */
	if (kvm_nlist(kd, nl) < 0)
		ERROR("main: kvm_nlist");

	return 0;
}

/*
 * Get a piece of kernel memory with error handling.
 * Returns 1 if call succeeded, else 0 (zero).
 */
static int
getbuf(addr, buf, len, what)
	long    addr;
	char   *buf;
	int     len;
	char   *what;
{
	if (kvm_read(kd, addr, buf, len) < 0) {
		if (syslog_flag)
			syslog(LOG_ERR, "getbuf: kvm_read(%08lx, %d) - %s : %m",
			    addr, len, what);

		return 0;
	}
	return 1;
}

/*
 * Traverse the inpcb list until a match is found.
 * Returns NULL if no match.
 */
static struct socket *
getlist(tcbtablep, ktcbtablep, faddr, fport, laddr, lport)
	struct inpcbtable *tcbtablep, *ktcbtablep;
	struct in_addr *faddr;
	int     fport;
	struct in_addr *laddr;
	int     lport;
{
	struct inpcb *kpcbp, pcb;

	if (!tcbtablep)
		return (NULL);

	for (kpcbp = tcbtablep->inpt_queue.cqh_first;
	    kpcbp != (struct inpcb *) ktcbtablep;
	    kpcbp = pcb.inp_queue.cqe_next) {
		if (!getbuf((long) kpcbp, &pcb, sizeof(struct inpcb), "tcb"))
			break;
		if (pcb.inp_faddr.s_addr == faddr->s_addr &&
		    pcb.inp_laddr.s_addr == laddr->s_addr &&
		    pcb.inp_fport == fport && pcb.inp_lport == lport)
			return (pcb.inp_socket);
	}
	return (NULL);
}

/*
 * Return the user number for the connection owner
 */
int
k_getuid(faddr, fport, laddr, lport, uid)
	struct in_addr *faddr;
	int     fport;
	struct in_addr *laddr;
	int     lport;
	int    *uid;
{
	struct socket *sockp, sock;

	if (!getbuf(nl[N_TCBTABLE].n_value, &tcbtable, sizeof(tcbtable), "tcbtable"))
		return -1;

	sockp = getlist(&tcbtable, nl[N_TCBTABLE].n_value, faddr, fport, laddr,
	    lport);
	if (!sockp)
		return -1;

	if (!getbuf(sockp, &sock, sizeof sock, "socket"))
		return -1;
	if ((sock.so_state & SS_CONNECTOUT) == 0)
		return -1;
	*uid = sock.so_uid;
	return (0);
}