/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * 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.
 */



/*
 * netstat
 */
#include <sys/param.h>
#include <sys/queue.h>
#include <sys/socket.h>
#include <sys/callout.h>
#include <sys/socketvar.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>
#ifdef INET6
#include <netinet/ip6.h>
#endif
#include <netinet/in_pcb.h>
#include <netinet/ip_icmp.h>
#include <netinet/icmp_var.h>
#include <netinet/ip_var.h>
#include <netinet/tcp.h>
#include <netinet/tcpip.h>
#include <netinet/tcp_seq.h>
#define TCPSTATES
#include <netinet/tcp_fsm.h>
#include <netinet/tcp_var.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>

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

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

static void enter(struct xinpcb *, struct xsocket *so, int, const char *);
static char *inetname(struct sockaddr *);
static void inetprint(struct sockaddr *, const char *);

#define streq(a,b)      (strcmp(a,b)==0)
#define YMAX(w)         (getmaxy(w)-2)

WINDOW *
opennetstat(void)
{
        sethostent(1);
        setnetent(1);
        return (subwin(stdscr, LINES-3-1, 0, MAINWIN_ROW, 0));
}

struct netinfo {
        TAILQ_ENTRY(netinfo) chain;
        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 sockaddr_storage ni_lsa; /* local address */
        struct sockaddr_storage ni_fsa; /* foreign address */
        u_int   ni_rcvcc;               /* rcv buffer character count */
        u_int   ni_sndcc;               /* snd buffer character count */
};

static TAILQ_HEAD(netinfohead, netinfo) netcb = TAILQ_HEAD_INITIALIZER(netcb);

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

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

        endhostent();
        endnetent();
        TAILQ_FOREACH(p, &netcb, chain) {
                if (p->ni_line != -1)
                        lastrow--;
                p->ni_line = -1;
        }
        if (w != NULL) {
                wclear(w);
                wrefresh(w);
                delwin(w);
        }
}

static const char *miblist[] = {
        "net.inet.tcp.pcblist",
        "net.inet.udp.pcblist"
};

int
initnetstat(void)
{
        protos = TCP|UDP;
        return(1);
}

void
fetchnetstat(void)
{
        struct netinfo *p;
        int idx;
        struct xinpgen *inpg;
        char *cur, *end;
        struct xinpcb *xip = NULL;
        struct xtcpcb *xtp = NULL;
        int plen;
        size_t lsz;

        TAILQ_FOREACH(p, &netcb, chain)
                p->ni_seen = 0;
        if (protos&TCP) {
                idx = 0;
        } else if (protos&UDP) {
                idx = 1;
        } else {
                error("No protocols to display");
                return;
        }

        for (;idx < 2; idx++) {
                if (idx == 1 && !(protos&UDP))
                        break;
                inpg = (struct xinpgen *)sysctl_dynread(miblist[idx], &lsz);
                if (inpg == NULL) {
                        error("sysctl(%s...) failed", miblist[idx]);
                        continue;
                }
                /*
                 * We currently do no require a consistent pcb list.
                 * Try to be robust in case of struct size changes
                 */
                cur = ((char *)inpg) + inpg->xig_len;
                /* There is also a trailing struct xinpgen */
                end = ((char *)inpg) + lsz - inpg->xig_len;
                if (end <= cur) {
                        free(inpg);
                        continue;
                }
                if (idx == 0) { /* TCP */
                        xtp = (struct xtcpcb *)cur;
                        plen = xtp->xt_len;
                } else {
                        xip = (struct xinpcb *)cur;
                        plen = xip->xi_len;
                }
                while (cur + plen <= end) {
                        if (idx == 0) { /* TCP */
                                xtp = (struct xtcpcb *)cur;
                                xip = &xtp->xt_inp;
                        } else {
                                xip = (struct xinpcb *)cur;
                        }
                        cur += plen;

                        if (!aflag) {
                                if (xip->inp_vflag & INP_IPV4) {
                                        if (xip->inp_laddr.s_addr == INADDR_ANY)
                                                continue;
                                }
#ifdef INET6
                                else if (xip->inp_vflag & INP_IPV6) {
                                        if (memcmp(&xip->in6p_laddr,
                                            &in6addr_any, sizeof(in6addr_any))
                                            == 0)
                                                continue;
                                }
#endif
                        }
                        if (nhosts && !checkhost(&xip->inp_inc))
                                continue;
                        if (nports && !checkport(&xip->inp_inc))
                                continue;
                        if (idx == 0)
                                enter(xip, &xip->xi_socket, xtp->t_state,
                                    "tcp");
                        else
                                enter(xip, &xip->xi_socket, 0, "udp");
                }
                free(inpg);
        }
}

static void
enter(struct xinpcb *xip, struct xsocket *so, int state, const char *proto)
{
        struct in_conninfo *inc = &xip->inp_inc;
        uint8_t vflag = xip->inp_vflag;
        struct netinfo *p;
        struct sockaddr_storage lsa, fsa;
        struct sockaddr_in *sa4;
#ifdef INET6
        struct sockaddr_in6 *sa6;
#endif

        memset(&lsa, 0, sizeof(lsa));
        memset(&fsa, 0, sizeof(fsa));
        if (vflag & INP_IPV4) {
                sa4 = (struct sockaddr_in *)&lsa;
                sa4->sin_addr = inc->inc_laddr;
                sa4->sin_port = inc->inc_lport;
                sa4->sin_family = AF_INET;
                sa4->sin_len = sizeof(struct sockaddr_in);

                sa4 = (struct sockaddr_in *)&fsa;
                sa4->sin_addr = inc->inc_faddr;
                sa4->sin_port = inc->inc_fport;
                sa4->sin_family = AF_INET;
                sa4->sin_len = sizeof(struct sockaddr_in);
        }
#ifdef INET6
        else if (vflag & INP_IPV6) {
                sa6 = (struct sockaddr_in6 *)&lsa;
                memcpy(&sa6->sin6_addr, &inc->inc6_laddr,
                    sizeof(struct in6_addr));
                sa6->sin6_port = inc->inc_lport;
                sa6->sin6_family = AF_INET6;
                sa6->sin6_len = sizeof(struct sockaddr_in6);

                sa6 = (struct sockaddr_in6 *)&fsa;
                memcpy(&sa6->sin6_addr, &inc->inc6_faddr,
                    sizeof(struct in6_addr));
                sa6->sin6_port = inc->inc_fport;
                sa6->sin6_family = AF_INET6;
                sa6->sin6_len = sizeof(struct sockaddr_in6);
        }
#endif
        else
                return;

        /*
         * 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.
         */
        TAILQ_FOREACH(p, &netcb, chain) {
                if (!streq(proto, p->ni_proto))
                        continue;
                if (p->ni_lsa.ss_family != lsa.ss_family ||
                    memcmp(&p->ni_lsa, &lsa, lsa.ss_len) != 0)
                        continue;
                if (p->ni_fsa.ss_family == fsa.ss_family &&
                    memcmp(&p->ni_fsa, &fsa, fsa.ss_len) == 0)
                        break;
        }
        if (p == NULL) {
                if ((p = malloc(sizeof(*p))) == NULL) {
                        error("Out of memory");
                        return;
                }
                TAILQ_INSERT_HEAD(&netcb, p, chain);
                p->ni_line = -1;
                memcpy(&p->ni_lsa, &lsa, lsa.ss_len);
                memcpy(&p->ni_fsa, &fsa, fsa.ss_len);
                p->ni_proto = strdup(proto);
                p->ni_flags = NIF_LACHG|NIF_FACHG;
        }
        p->ni_state = state;
        p->ni_seen = 1;
        p->ni_rcvcc = so->so_rcv.sb_cc;
        p->ni_sndcc = so->so_snd.sb_cc;
}

/* 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)
{
        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)");
}

void
shownetstat(void)
{
        struct netinfo *p, *q;
        char proto[6];
        const char *family = "";

        /*
         * First, delete any connections that have gone
         * away and adjust the position of connections
         * below to reflect the deleted line.
         */
        p = TAILQ_FIRST(&netcb);
        while (p != NULL) {
                if (p->ni_line == -1 || p->ni_seen) {
                        p = TAILQ_NEXT(p, chain);
                        continue;
                }
                wmove(wnd, p->ni_line, 0); wdeleteln(wnd);
                TAILQ_FOREACH(q, &netcb, chain)
                        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 = TAILQ_NEXT(p, chain);
                TAILQ_REMOVE(&netcb, p, chain);
                free(p);
                p = q;
        }
        /*
         * Update existing connections and add new ones.
         */
        TAILQ_FOREACH(p, &netcb, chain) {
                if (p->ni_line == -1) {
                        /*
                         * Add a new entry if possible.
                         */
                        if (lastrow > YMAX(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);
                        inetprint((struct sockaddr *)&p->ni_lsa, p->ni_proto);
                        p->ni_flags &= ~NIF_LACHG;
                }
                if (p->ni_flags & NIF_FACHG) {
                        wmove(wnd, p->ni_line, FADDR);
                        inetprint((struct sockaddr *)&p->ni_fsa, p->ni_proto);
                        p->ni_flags &= ~NIF_FACHG;
                }
#ifdef INET6
                family = (p->ni_lsa.ss_family == AF_INET) ? "4" : "6";
#endif
                snprintf(proto, sizeof(proto), "%s%s", p->ni_proto, family);
                mvwaddstr(wnd, p->ni_line, PROTO, proto);
                mvwprintw(wnd, p->ni_line, RCVCC, "%6u", p->ni_rcvcc);
                mvwprintw(wnd, p->ni_line, SNDCC, "%6u", 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 < YMAX(wnd)) {
                wmove(wnd, lastrow, 0); wclrtobot(wnd);
                wmove(wnd, YMAX(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 sockaddr *sa, const char *proto)
{
        struct servent *sp = 0;
        char line[80], *cp;
        int port;

        switch (sa->sa_family) {
        case AF_INET:
                port = ((struct sockaddr_in *)sa)->sin_port;
                break;
#ifdef INET6
        case AF_INET6:
                port = ((struct sockaddr_in6 *)sa)->sin6_port;
                break;
#endif
        default:
                port = 0;
                break;
        }
        snprintf(line, sizeof(line), "%.*s.", 16, inetname(sa));
        cp = strchr(line, '\0');
        if (!nflag && port)
                sp = getservbyport(port, proto);
        if (sp || port == 0)
                snprintf(cp, sizeof(line) - (cp - line), "%.8s",
                    sp ? sp->s_name : "*");
        else
                snprintf(cp, sizeof(line) - (cp - line), "%d",
                    ntohs((u_short)port));
        /* pad to full column to clear any garbage */
        cp = strchr(line, '\0');
        while (cp - line < 22)
                *cp++ = ' ';
        line[22] = '\0';
        waddstr(wnd, line);
}

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

#ifdef INET6
        if (sa->sa_family == AF_INET6) {
                if (memcmp(&((struct sockaddr_in6 *)sa)->sin6_addr,
                    &in6addr_any, sizeof(in6addr_any)) == 0)
                        strcpy(line, "*");
                else
                        getnameinfo(sa, sa->sa_len, line, sizeof(line), NULL, 0,
                            nflag ? NI_NUMERICHOST : 0);
                return (line);
        }
#endif

        in = ((struct sockaddr_in *)sa)->sin_addr;
        if (!nflag && in.s_addr != INADDR_ANY) {
                hp = gethostbyaddr((char *)&in, sizeof (in), AF_INET);
                if (hp)
                        cp = hp->h_name;
        }
        if (in.s_addr == INADDR_ANY)
                strcpy(line, "*");
        else if (cp)
                snprintf(line, sizeof(line), "%s", cp);
        else {
                in.s_addr = ntohl(in.s_addr);
#define C(x)    ((x) & 0xff)
                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));
        }
        return (line);
}

int
cmdnetstat(const char *cmd, const char *args)
{
        if (prefix(cmd, "all")) {
                aflag = !aflag;
                goto fixup;
        }
        if  (prefix(cmd, "numbers") || prefix(cmd, "names")) {
                struct netinfo *p;
                int new;

                new = prefix(cmd, "numbers");
                if (new == nflag)
                        return (1);
                TAILQ_FOREACH(p, &netcb, chain) {
                        if (p->ni_line == -1)
                                continue;
                        p->ni_flags |= NIF_LACHG|NIF_FACHG;
                }
                nflag = new;
                goto redisplay;
        }
        if (!netcmd(cmd, args))
                return (0);
fixup:
        fetchnetstat();
redisplay:
        shownetstat();
        refresh();
        return (1);
}