/*      $NetBSD: netstat.c,v 1.32 2022/10/28 05:27:17 ozaki-r Exp $     */

/*-
 * Copyright (c) 1980, 1992, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)netstat.c   8.1 (Berkeley) 6/6/93";
#endif
__RCSID("$NetBSD: netstat.c,v 1.32 2022/10/28 05:27:17 ozaki-r Exp $");
#endif /* not lint */

/*
 * netstat
 */
#include <sys/param.h>
#include <sys/socketvar.h>
#include <sys/mbuf.h>
#include <sys/protosw.h>

#include <netinet/in.h>

#include <arpa/inet.h>
#include <net/route.h>

#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/ip_icmp.h>
#include <netinet/icmp_var.h>
#include <netinet/ip_var.h>
#ifdef INET6
#include <netinet/ip6.h>
#include <netinet6/in6_pcb.h>
#endif
#include <netinet/tcp.h>
#include <netinet/tcp_seq.h>
#define TCPSTATES
#include <netinet/tcp_fsm.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
#include <netinet/tcp_debug.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>

#include <netdb.h>
#include <stdlib.h>
#include <string.h>

#include "systat.h"
#include "extern.h"

static void fetchnetstat4(void *, int);
static void enter(struct inpcb *, struct socket *, int, const char *);
static const char *inetname(struct in_addr);
static void inetprint(struct in_addr *, int, const char *);
#ifdef INET6
static void fetchnetstat6(void *, int);
static void enter6(struct inpcb *, struct socket *, int, const char *);
static const char *inet6name(struct in6_addr *);
static void inet6print(struct in6_addr *, int, const char *);
#endif

#define streq(a,b)      (strcmp(a,b)==0)

struct netinfo {
        struct  netinfo *ni_forw, *ni_prev;
        int     ni_family;
        short   ni_line;                /* line on screen */
        short   ni_seen;                /* 0 when not present in list */
        short   ni_flags;
#define NIF_LACHG       0x1             /* local address changed */
#define NIF_FACHG       0x2             /* foreign address changed */
        short   ni_state;               /* tcp state */
        const char      *ni_proto;              /* protocol */
        struct  in_addr ni_laddr;       /* local address */
#ifdef INET6
        struct  in6_addr ni_laddr6;     /* local address */
#endif
        long    ni_lport;               /* local port */
        struct  in_addr ni_faddr;       /* foreign address */
#ifdef INET6
        struct  in6_addr ni_faddr6;     /* foreign address */
#endif
        long    ni_fport;               /* foreign port */
        long    ni_rcvcc;               /* rcv buffer character count */
        long    ni_sndcc;               /* snd buffer character count */
};

static struct {
        struct  netinfo *ni_forw, *ni_prev;
} netcb;

struct netinfo *nhead;

static  int aflag = 0;
int nflag = 0;
static  int lastrow = 1;

WINDOW *
opennetstat(void)
{

        sethostent(1);
        setnetent(1);
        return (subwin(stdscr, -1, 0, 5, 0));
}

void
closenetstat(WINDOW *w)
{
        struct netinfo *p;

        endhostent();
        endnetent();
        p = netcb.ni_forw;
        while (p != nhead) {
                if (p->ni_line != -1)
                        lastrow--;
                p->ni_line = -1;
                p = p->ni_forw;
        }
        if (w != NULL) {
                wclear(w);
                wrefresh(w);
                delwin(w);
        }
}

static struct nlist namelist[] = {
#define X_TCBTABLE      0
        { .n_name = "_tcbtable" },
#define X_UDBTABLE      1
        { .n_name = "_udbtable" },
        { .n_name = NULL },
};

int
initnetstat(void)
{
        int n;

        n = kvm_nlist(kd, namelist);
        if (n < 0) {
                nlisterr(namelist);
                return(0);
        } else if (n == sizeof(namelist) / sizeof(namelist[0]) - 1) {
                error("No symbols in namelist");
                return(0);
        }

        nhead = (struct netinfo *)(void *)&netcb;

        netcb.ni_forw = netcb.ni_prev = nhead;
        protos = TCP|UDP;
        return(1);
}

void
fetchnetstat(void)
{
        struct netinfo *p;

        if (namelist[X_TCBTABLE].n_value == 0)
                return;
        for (p = netcb.ni_forw; p != nhead; p = p->ni_forw)
                p->ni_seen = 0;

        if ((protos & (TCP | UDP)) == 0) {
                error("No protocols to display");
                return;
        }
        if ((protos & TCP) && namelist[X_TCBTABLE].n_type)
                fetchnetstat4(NPTR(X_TCBTABLE), 1);
        if ((protos & UDP) && namelist[X_UDBTABLE].n_type)
                fetchnetstat4(NPTR(X_UDBTABLE), 0);
#ifdef INET6
        if ((protos & TCP) && namelist[X_TCBTABLE].n_type)
                fetchnetstat6(NPTR(X_TCBTABLE), 1);
        if ((protos & UDP) && namelist[X_UDBTABLE].n_type)
                fetchnetstat6(NPTR(X_UDBTABLE), 0);
#endif
}

static void
fetchnetstat4(void *off, int istcp)
{
        struct inpcbtable pcbtable;
        struct inpcb **pprev, *next;
        struct netinfo *p;
        struct inpcb *inpcbp, *inp;
        struct in4pcb in4pcb;
        struct socket sockb;
        struct tcpcb tcpcb;

        KREAD(off, &pcbtable, sizeof pcbtable);
        pprev = &((struct inpcbtable *)off)->inpt_queue.tqh_first;
        next = TAILQ_FIRST(&pcbtable.inpt_queue);
        while (next != TAILQ_END(&pcbtable.inpt_queue)) {
                inpcbp = (struct inpcb *)next;
                KREAD(inpcbp, &in4pcb, sizeof (in4pcb));
                inp = (struct inpcb *)&in4pcb;
                if (inp->inp_queue.tqe_prev != pprev) {
                        for (p = netcb.ni_forw; p != nhead; p = p->ni_forw)
                                p->ni_seen = 1;
                        error("Kernel state in transition");
                        return;
                }
                pprev = &next->inp_queue.tqe_next;
                next = inp->inp_queue.tqe_next;

                if (inp->inp_af != AF_INET)
                        continue;
                if (!aflag && inet_lnaof(in4p_laddr(inp)) == INADDR_ANY)
                        continue;
                if (nhosts && !checkhost(inp))
                        continue;
                if (nports && !checkport(inp))
                        continue;
                KREAD(inp->inp_socket, &sockb, sizeof (sockb));
                if (istcp) {
                        KREAD(inp->inp_ppcb, &tcpcb, sizeof (tcpcb));
                        enter(inp, &sockb, tcpcb.t_state, "tcp");
                } else
                        enter(inp, &sockb, 0, "udp");
        }
}

#ifdef INET6
static void
fetchnetstat6(void *off, int istcp)
{
        struct inpcbtable pcbtable;
        struct inpcb **pprev, *next;
        struct netinfo *p;
        struct socket sockb;
        struct tcpcb tcpcb;
        struct inpcb *inp, *inpcbp;
        struct in6pcb in6pcb;

        KREAD(off, &pcbtable, sizeof pcbtable);
        pprev = &((struct inpcbtable *)off)->inpt_queue.tqh_first;
        next = TAILQ_FIRST(&pcbtable.inpt_queue);
        while (next != TAILQ_END(&pcbtable.inpt_queue)) {
                inpcbp = (struct inpcb *)next;
                KREAD(inpcbp, &in6pcb, sizeof (in6pcb));
                inp = (struct inpcb *)&in6pcb;
                if (inp->inp_queue.tqe_prev != pprev) {
                        for (p = netcb.ni_forw; p != nhead; p = p->ni_forw)
                                p->ni_seen = 1;
                        error("Kernel state in transition");
                        return;
                }
                pprev = &next->inp_queue.tqe_next;
                next = inp->inp_queue.tqe_next;

                if (inp->inp_af != AF_INET6)
                        continue;
                if (!aflag && IN6_IS_ADDR_UNSPECIFIED(&in6p_laddr(inp)))
                        continue;
                if (nhosts && !checkhost(inp))
                        continue;
                if (nports && !checkport(inp))
                        continue;
                KREAD(inp->inp_socket, &sockb, sizeof (sockb));
                if (istcp) {
                        KREAD(inp->inp_ppcb, &tcpcb, sizeof (tcpcb));
                        enter6(inp, &sockb, tcpcb.t_state, "tcp");
                } else
                        enter6(inp, &sockb, 0, "udp");
        }
}
#endif /*INET6*/

static void
enter(struct inpcb *inp, struct socket *so, int state, const char *proto)
{
        struct netinfo *p;

        /*
         * Only take exact matches, any sockets with
         * previously unbound addresses will be deleted
         * below in the display routine because they
         * will appear as ``not seen'' in the kernel
         * data structures.
         */
        for (p = netcb.ni_forw; p != nhead; p = p->ni_forw) {
                if (p->ni_family != AF_INET)
                        continue;
                if (!streq(proto, p->ni_proto))
                        continue;
                if (p->ni_lport != inp->inp_lport ||
                    p->ni_laddr.s_addr != in4p_laddr(inp).s_addr)
                        continue;
                if (p->ni_faddr.s_addr == in4p_faddr(inp).s_addr &&
                    p->ni_fport == inp->inp_fport)
                        break;
        }
        if (p == nhead) {
                if ((p = malloc(sizeof(*p))) == NULL) {
                        error("Out of memory");
                        return;
                }
                p->ni_prev = nhead;
                p->ni_forw = netcb.ni_forw;
                netcb.ni_forw->ni_prev = p;
                netcb.ni_forw = p;
                p->ni_line = -1;
                p->ni_laddr = in4p_laddr(inp);
                p->ni_lport = inp->inp_lport;
                p->ni_faddr = in4p_faddr(inp);
                p->ni_fport = inp->inp_fport;
                p->ni_proto = proto;
                p->ni_flags = NIF_LACHG | NIF_FACHG;
                p->ni_family = AF_INET;
        }
        p->ni_rcvcc = so->so_rcv.sb_cc;
        p->ni_sndcc = so->so_snd.sb_cc;
        p->ni_state = state;
        p->ni_seen = 1;
}

#ifdef INET6
static void
enter6(struct inpcb *inp, struct socket *so, int state, const char *proto)
{
        struct netinfo *p;

        /*
         * Only take exact matches, any sockets with
         * previously unbound addresses will be deleted
         * below in the display routine because they
         * will appear as ``not seen'' in the kernel
         * data structures.
         */
        for (p = netcb.ni_forw; p != nhead; p = p->ni_forw) {
                if (p->ni_family != AF_INET6)
                        continue;
                if (!streq(proto, p->ni_proto))
                        continue;
                if (p->ni_lport != inp->inp_lport ||
                    !IN6_ARE_ADDR_EQUAL(&p->ni_laddr6, &in6p_laddr(inp)))
                        continue;
                if (IN6_ARE_ADDR_EQUAL(&p->ni_faddr6, &in6p_faddr(inp)) &&
                    p->ni_fport == inp->inp_fport)
                        break;
        }
        if (p == nhead) {
                if ((p = malloc(sizeof(*p))) == NULL) {
                        error("Out of memory");
                        return;
                }
                p->ni_prev = nhead;
                p->ni_forw = netcb.ni_forw;
                netcb.ni_forw->ni_prev = p;
                netcb.ni_forw = p;
                p->ni_line = -1;
                p->ni_laddr6 = in6p_laddr(inp);
                p->ni_lport = inp->inp_lport;
                p->ni_faddr6 = in6p_faddr(inp);
                p->ni_fport = inp->inp_fport;
                p->ni_proto = proto;
                p->ni_flags = NIF_LACHG | NIF_FACHG;
                p->ni_family = AF_INET6;
        }
        p->ni_rcvcc = so->so_rcv.sb_cc;
        p->ni_sndcc = so->so_snd.sb_cc;
        p->ni_state = state;
        p->ni_seen = 1;
}
#endif

/* column locations */
#define LADDR   0
#define FADDR   LADDR+23
#define PROTO   FADDR+23
#define RCVCC   PROTO+6
#define SNDCC   RCVCC+7
#define STATE   SNDCC+7

void
labelnetstat(void)
{
        struct netinfo *p;

        if (namelist[X_TCBTABLE].n_type == 0)
                return;
        wmove(wnd, 0, 0); wclrtobot(wnd);
        mvwaddstr(wnd, 0, LADDR, "Local Address");
        mvwaddstr(wnd, 0, FADDR, "Foreign Address");
        mvwaddstr(wnd, 0, PROTO, "Proto");
        mvwaddstr(wnd, 0, RCVCC, "Recv-Q");
        mvwaddstr(wnd, 0, SNDCC, "Send-Q");
        mvwaddstr(wnd, 0, STATE, "(state)"); 
        
        for (p = netcb.ni_forw; p != nhead; p = p->ni_forw) {
                if (p->ni_line == -1)
                        continue;
                p->ni_flags |= NIF_LACHG | NIF_FACHG;
        }
}

void
shownetstat(void)
{
        struct netinfo *p, *q;

        /*
         * First, delete any connections that have gone
         * away and adjust the position of connections
         * below to reflect the deleted line.
         */
        p = netcb.ni_forw;
        while (p != nhead) {
                if (p->ni_line == -1 || p->ni_seen) {
                        p = p->ni_forw;
                        continue;
                }
                wmove(wnd, p->ni_line, 0);
                wdeleteln(wnd);
                for (q = netcb.ni_forw; q != nhead; q = q->ni_forw)
                        if (q != p && q->ni_line > p->ni_line) {
                                q->ni_line--;
                                /* this shouldn't be necessary */
                                q->ni_flags |= NIF_LACHG | NIF_FACHG;
                        }
                lastrow--;
                q = p->ni_forw;
                p->ni_prev->ni_forw = p->ni_forw;
                p->ni_forw->ni_prev = p->ni_prev;
                free(p);
                p = q;
        }
        /*
         * Update existing connections and add new ones.
         */
        for (p = netcb.ni_forw; p != nhead; p = p->ni_forw) {
                if (p->ni_line == -1) {
                        /*
                         * Add a new entry if possible.
                         */
                        if (lastrow > getmaxy(wnd))
                                continue;
                        p->ni_line = lastrow++;
                        p->ni_flags |= NIF_LACHG | NIF_FACHG;
                }
                if (p->ni_flags & NIF_LACHG) {
                        wmove(wnd, p->ni_line, LADDR);
                        switch (p->ni_family) {
                        case AF_INET:
                                inetprint(&p->ni_laddr, p->ni_lport,
                                        p->ni_proto);
                                break;
#ifdef INET6
                        case AF_INET6:
                                inet6print(&p->ni_laddr6, p->ni_lport,
                                        p->ni_proto);
                                break;
#endif
                        }
                        p->ni_flags &= ~NIF_LACHG;
                }
                if (p->ni_flags & NIF_FACHG) {
                        wmove(wnd, p->ni_line, FADDR);
                        switch (p->ni_family) {
                        case AF_INET:
                                inetprint(&p->ni_faddr, p->ni_fport,
                                        p->ni_proto);
                                break;
#ifdef INET6
                        case AF_INET6:
                                inet6print(&p->ni_faddr6, p->ni_fport,
                                        p->ni_proto);
                                break;
#endif
                        }
                        p->ni_flags &= ~NIF_FACHG;
                }
                mvwaddstr(wnd, p->ni_line, PROTO, p->ni_proto);
#ifdef INET6
                if (p->ni_family == AF_INET6)
                        waddstr(wnd, "6");
#endif
                mvwprintw(wnd, p->ni_line, RCVCC, "%6ld", p->ni_rcvcc);
                mvwprintw(wnd, p->ni_line, SNDCC, "%6ld", p->ni_sndcc);
                if (streq(p->ni_proto, "tcp")) {
                        if (p->ni_state < 0 || p->ni_state >= TCP_NSTATES)
                                mvwprintw(wnd, p->ni_line, STATE, "%d",
                                    p->ni_state);
                        else
                                mvwaddstr(wnd, p->ni_line, STATE,
                                    tcpstates[p->ni_state]);
                }
                wclrtoeol(wnd);
        }
        if (lastrow < getmaxy(wnd)) {
                wmove(wnd, lastrow, 0); wclrtobot(wnd);
                wmove(wnd, getmaxy(wnd), 0); wdeleteln(wnd);    /* XXX */
        }
}

/*
 * Pretty print an Internet address (net address + port).
 * If the nflag was specified, use numbers instead of names.
 */
static void
inetprint(struct in_addr *in, int port, const char *proto)
{
        struct servent *sp = 0;
        char line[80], *cp;

        (void)snprintf(line, sizeof line, "%.*s.", 16, inetname(*in));
        cp = strchr(line, '\0');
        if (!nflag && port)
                sp = getservbyport(port, proto);
        if (sp || port == 0)
                (void)snprintf(cp, line + sizeof line - cp, "%.8s",
                     sp ? sp->s_name : "*");
        else
                (void)snprintf(cp, line + sizeof line - cp, "%d",
                     ntohs((u_short)port));
        /* pad to full column to clear any garbage */
        cp = strchr(line, '\0');
        while (cp - line < 22)
                *cp++ = ' ';
        *cp = '\0';
        waddstr(wnd, line);
}

#ifdef INET6
static void
inet6print(struct in6_addr *in6, int port, const char *proto)
{
        struct servent *sp = 0;
        char line[80], *cp;

        (void)snprintf(line, sizeof line, "%.*s.", 16, inet6name(in6));
        cp = strchr(line, '\0');
        if (!nflag && port)
                sp = getservbyport(port, proto);
        if (sp || port == 0)
                (void)snprintf(cp, line + sizeof line - cp, "%.8s",
                     sp ? sp->s_name : "*");
        else
                (void)snprintf(cp, line + sizeof line - cp, "%d",
                     ntohs((u_short)port));
        /* pad to full column to clear any garbage */
        cp = strchr(line, '\0');
        while (cp - line < 22)
                *cp++ = ' ';
        *cp = '\0';
        waddstr(wnd, line);
}
#endif

/*
 * Construct an Internet address representation.
 * If the nflag has been supplied, give 
 * numeric value, otherwise try for symbolic name.
 */
static const char *
inetname(struct in_addr in)
{
        char *cp = 0;
        static char line[50];
        struct hostent *hp;
        struct netent *np;

        if (!nflag && in.s_addr != INADDR_ANY) {
                int net = inet_netof(in);
                int lna = inet_lnaof(in);

                if (lna == INADDR_ANY) {
                        np = getnetbyaddr(net, AF_INET);
                        if (np)
                                cp = np->n_name;
                }
                if (cp == 0) {
                        hp = gethostbyaddr((char *)&in, sizeof (in), AF_INET);
                        if (hp)
                                cp = hp->h_name;
                }
        }
        if (in.s_addr == INADDR_ANY)
                strlcpy(line, "*", sizeof(line));
        else if (cp)
                strlcpy(line, cp, sizeof(line));
        else {
                in.s_addr = ntohl(in.s_addr);
#define C(x)    ((x) & 0xff)
                (void)snprintf(line, sizeof line, "%u.%u.%u.%u",
                    C(in.s_addr >> 24), C(in.s_addr >> 16),
                    C(in.s_addr >> 8), C(in.s_addr));
#undef C
        }
        return (line);
}

#ifdef INET6
static const char *
inet6name(struct in6_addr *in6)
{
        static char line[NI_MAXHOST];
        struct sockaddr_in6 sin6;
        int flags;

        if (nflag)
                flags = NI_NUMERICHOST;
        else
                flags = 0;
        if (IN6_IS_ADDR_UNSPECIFIED(in6))
                return "*";
        memset(&sin6, 0, sizeof(sin6));
        sin6.sin6_family = AF_INET6;
        sin6.sin6_len = sizeof(struct sockaddr_in6);
        sin6.sin6_addr = *in6;
        if (getnameinfo((struct sockaddr *)&sin6, sin6.sin6_len,
                        line, sizeof(line), NULL, 0, flags) == 0)
                return line;
        return "?";
}
#endif

/* please note: there are also some netstat commands in netcmds.c */

void
netstat_all(char *args)
{
        aflag = !aflag;
        fetchnetstat();
        shownetstat();
        refresh();
}

void
netstat_names(char *args)
{

        if (nflag == 0)
                return;
        
        nflag = 0;
        wclear(wnd);
        labelnetstat();
        shownetstat();
        refresh();
}

void
netstat_numbers(char *args)
{

        if (nflag != 0)
                return;
        
        nflag = 1;
        wclear(wnd);
        labelnetstat();
        shownetstat();
        refresh();
}