/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (C) 2011 Hiroki Sato <hrs@FreeBSD.org>
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT 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 PROJECT 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/param.h>
#include <sys/queue.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/un.h>
#include <sys/uio.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <netinet/in.h>
#include <netinet/icmp6.h>
#include <fcntl.h>
#include <errno.h>
#include <netdb.h>
#include <unistd.h>
#include <poll.h>
#include <signal.h>
#include <string.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <syslog.h>

#include "rtadvd.h"
#include "if.h"
#include "pathnames.h"
#include "control.h"

#define CM_RECV_TIMEOUT 30

int
cm_recv(int fd, char *buf)
{
        ssize_t n;
        struct ctrl_msg_hdr     *cm;
        char *msg;
        struct pollfd pfds[1];
        int i;

        syslog(LOG_DEBUG, "<%s> enter, fd=%d", __func__, fd);

        memset(buf, 0, CM_MSG_MAXLEN);
        cm = (struct ctrl_msg_hdr *)buf;
        msg = (char *)buf + sizeof(*cm);

        pfds[0].fd = fd;
        pfds[0].events = POLLIN;

        for (;;) {
                i = poll(pfds, nitems(pfds),
                    CM_RECV_TIMEOUT);

                if (i == 0)
                        continue;

                if (i < 0) {
                        syslog(LOG_ERR, "<%s> poll error: %s",
                            __func__, strerror(errno));
                        continue;
                }

                if (pfds[0].revents & POLLIN) {
                        n = read(fd, cm, sizeof(*cm));
                        if (n < 0 && errno == EAGAIN) {
                                syslog(LOG_DEBUG,
                                    "<%s> waiting...", __func__);
                                continue;
                        }
                        break;
                }
        }

        if (n != (ssize_t)sizeof(*cm)) {
                syslog(LOG_WARNING,
                    "<%s> received a too small message.", __func__);
                goto cm_recv_err;
        }
        if (cm->cm_len > CM_MSG_MAXLEN) {
                syslog(LOG_WARNING,
                    "<%s> received a too large message.", __func__);
                goto cm_recv_err;
        }
        if (cm->cm_version != CM_VERSION) {
                syslog(LOG_WARNING,
                    "<%s> version mismatch", __func__);
                goto cm_recv_err;
        }
        if (cm->cm_type >= CM_TYPE_MAX) {
                syslog(LOG_WARNING,
                    "<%s> invalid msg type.", __func__);
                goto cm_recv_err;
        }

        syslog(LOG_DEBUG,
            "<%s> ctrl msg received: type=%d", __func__,
            cm->cm_type);

        if (cm->cm_len > sizeof(*cm)) {
                size_t msglen = cm->cm_len - sizeof(*cm);

                syslog(LOG_DEBUG,
                    "<%s> ctrl msg has payload (len=%zu)", __func__,
                    msglen);

                for (;;) {
                        i = poll(pfds, nitems(pfds),
                            CM_RECV_TIMEOUT);

                        if (i == 0)
                                continue;

                        if (i < 0) {
                                syslog(LOG_ERR, "<%s> poll error: %s",
                                    __func__, strerror(errno));
                                continue;
                        }

                        if (pfds[0].revents & POLLIN) {
                                n = read(fd, msg, msglen);
                                if (n < 0 && errno == EAGAIN) {
                                        syslog(LOG_DEBUG,
                                            "<%s> waiting...", __func__);
                                        continue;
                                }
                        }
                        break;
                }
                if (n != (ssize_t)msglen) {
                        syslog(LOG_WARNING,
                            "<%s> payload size mismatch.", __func__);
                        goto cm_recv_err;
                }
                buf[CM_MSG_MAXLEN - 1] = '\0';
        }

        return (0);

cm_recv_err:
        close(fd);
        return (-1);
}

int
cm_send(int fd, char *buf)
{
        struct iovec iov[2];
        int iovcnt;
        ssize_t len;
        ssize_t iov_len_total;
        struct ctrl_msg_hdr *cm;
        char *msg;

        cm = (struct ctrl_msg_hdr *)buf;
        msg = (char *)buf + sizeof(*cm);

        iovcnt = 1;
        iov[0].iov_base = cm;
        iov[0].iov_len = sizeof(*cm);
        iov_len_total = iov[0].iov_len;
        if (cm->cm_len > sizeof(*cm)) {
                iovcnt++;
                iov[1].iov_base = msg;
                iov[1].iov_len = cm->cm_len - iov[0].iov_len;
                iov_len_total += iov[1].iov_len;
        }

        syslog(LOG_DEBUG,
            "<%s> ctrl msg send: type=%d, count=%d, total_len=%zd", __func__,
            cm->cm_type, iovcnt, iov_len_total);

        len = writev(fd, iov, iovcnt);
        syslog(LOG_DEBUG,
            "<%s> ctrl msg send: length=%zd", __func__, len);

        if (len == -1) {
                syslog(LOG_DEBUG,
                    "<%s> write failed: (%d)%s", __func__, errno,
                    strerror(errno));
                close(fd);
                return (-1);
        }

        syslog(LOG_DEBUG,
            "<%s> write length = %zd (actual)", __func__, len);
        syslog(LOG_DEBUG,
            "<%s> write length = %zd (expected)", __func__, iov_len_total);

        if (len != iov_len_total) {
                close(fd);
                return (-1);
        }

        return (0);
}

int
csock_accept(struct sockinfo *s)
{
        struct sockaddr_un      sun;
        int     flags;
        int     fd;

        sun.sun_len = sizeof(sun);
        if ((fd = accept(s->si_fd, (struct sockaddr *)&sun,
                    (socklen_t *)&sun.sun_len)) == -1) {
                if (errno != EWOULDBLOCK && errno != EINTR)
                        syslog(LOG_WARNING, "<%s> accept ", __func__);
                syslog(LOG_WARNING, "<%s> Xaccept: %s", __func__, strerror(errno));
                return (-1);
        }
        if ((flags = fcntl(fd, F_GETFL, 0)) == -1) {
                syslog(LOG_WARNING, "<%s> fcntl F_GETFL", __func__);
                close(s->si_fd);
                return (-1);
        }
        if ((flags = fcntl(fd, F_SETFL, flags | O_NONBLOCK)) == -1) {
                syslog(LOG_WARNING, "<%s> fcntl F_SETFL", __func__);
                return (-1);
        }
        syslog(LOG_DEBUG, "<%s> accept connfd=%d, listenfd=%d", __func__,
            fd, s->si_fd);

        return (fd);
}

int
csock_close(struct sockinfo *s)
{
        close(s->si_fd);
        unlink(s->si_name);
        syslog(LOG_DEBUG, "<%s> remove %s", __func__, s->si_name);
        return (0);
}

int
csock_listen(struct sockinfo *s)
{
        if (s->si_fd == -1) {
                syslog(LOG_ERR, "<%s> listen failed", __func__);
                return (-1);
        }
        if (listen(s->si_fd, SOCK_BACKLOG) == -1) {
                syslog(LOG_ERR, "<%s> listen failed", __func__);
                return (-1);
        }

        return (0);
}

int
csock_open(struct sockinfo *s, mode_t mode)
{
        int flags;
        struct sockaddr_un      sun;
        mode_t  old_umask;

        if (s == NULL) {
                syslog(LOG_ERR, "<%s> internal error.", __func__);
                exit(1);
        }
        if (s->si_name == NULL)
                s->si_name = _PATH_CTRL_SOCK;

        if ((s->si_fd = socket(PF_UNIX, SOCK_STREAM, 0)) == -1) {
                syslog(LOG_ERR,
                    "<%s> cannot open control socket", __func__);
                return (-1);
        }
        memset(&sun, 0, sizeof(sun));
        sun.sun_family = AF_UNIX;
        sun.sun_len = sizeof(sun);
        strlcpy(sun.sun_path, s->si_name, sizeof(sun.sun_path));

        if (unlink(s->si_name) == -1)
                if (errno != ENOENT) {
                        syslog(LOG_ERR,
                            "<%s> unlink %s", __func__, s->si_name);
                        close(s->si_fd);
                        return (-1);
                }
        old_umask = umask(S_IXUSR|S_IXGRP|S_IXOTH);
        if (bind(s->si_fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) {
                syslog(LOG_ERR,
                    "<%s> bind failed: %s", __func__, s->si_name);
                close(s->si_fd);
                umask(old_umask);
                return (-1);
        }
        umask(old_umask);
        if (chmod(s->si_name, mode) == -1) {
                syslog(LOG_ERR,
                    "<%s> chmod failed: %s", __func__, s->si_name);
                goto csock_open_err;
        }
        if ((flags = fcntl(s->si_fd, F_GETFL, 0)) == -1) {
                syslog(LOG_ERR,
                    "<%s> fcntl F_GETFL failed: %s", __func__, s->si_name);
                goto csock_open_err;
        }
        if ((flags = fcntl(s->si_fd, F_SETFL, flags | O_NONBLOCK)) == -1) {
                syslog(LOG_ERR,
                    "<%s> fcntl F_SETFL failed: %s", __func__, s->si_name);
                goto csock_open_err;
        }

        return (s->si_fd);

csock_open_err:
        close(s->si_fd);
        unlink(s->si_name);
        return (-1);
}

struct ctrl_msg_pl *
cm_bin2pl(char *str, struct ctrl_msg_pl *cp)
{
        size_t len;
        size_t *lenp;
        char *p;

        memset(cp, 0, sizeof(*cp));

        p = str;

        lenp = (size_t *)p;
        len = *lenp++;
        p = (char *)lenp;
        syslog(LOG_DEBUG, "<%s> len(ifname) = %zu", __func__, len);
        if (len > 0) {
                cp->cp_ifname = malloc(len + 1);
                if (cp->cp_ifname == NULL) {
                        syslog(LOG_ERR, "<%s> malloc", __func__);
                        exit(1);
                }
                memcpy(cp->cp_ifname, p, len);
                cp->cp_ifname[len] = '\0';
                p += len;
        }

        lenp = (size_t *)p;
        len = *lenp++;
        p = (char *)lenp;
        syslog(LOG_DEBUG, "<%s> len(key) = %zu", __func__, len);
        if (len > 0) {
                cp->cp_key = malloc(len + 1);
                if (cp->cp_key == NULL) {
                        syslog(LOG_ERR, "<%s> malloc", __func__);
                        exit(1);
                }
                memcpy(cp->cp_key, p, len);
                cp->cp_key[len] = '\0';
                p += len;
        }

        lenp = (size_t *)p;
        len = *lenp++;
        p = (char *)lenp;
        syslog(LOG_DEBUG, "<%s> len(val) = %zu", __func__, len);
        if (len > 0) {
                cp->cp_val = malloc(len + 1);
                if (cp->cp_val == NULL) {
                        syslog(LOG_ERR, "<%s> malloc", __func__);
                        exit(1);
                }
                memcpy(cp->cp_val, p, len);
                cp->cp_val[len] = '\0';
                cp->cp_val_len = len;
        } else
                cp->cp_val_len = 0;

        return (cp);
}

size_t
cm_pl2bin(char *str, struct ctrl_msg_pl *cp)
{
        size_t len;
        size_t *lenp;
        char *p;
        struct ctrl_msg_hdr *cm;

        len = sizeof(size_t);
        if (cp->cp_ifname != NULL)
                len += strlen(cp->cp_ifname);
        len += sizeof(size_t);
        if (cp->cp_key != NULL)
                len += strlen(cp->cp_key);
        len += sizeof(size_t);
        if (cp->cp_val != NULL && cp->cp_val_len > 0)
                len += cp->cp_val_len;

        if (len > CM_MSG_MAXLEN - sizeof(*cm)) {
                syslog(LOG_DEBUG, "<%s> msg too long (len=%zu)",
                    __func__, len);
                return (0);
        }
        syslog(LOG_DEBUG, "<%s> msglen=%zu", __func__, len);
        memset(str, 0, len);
        p = str;
        lenp = (size_t *)p;
        
        if (cp->cp_ifname != NULL) {
                *lenp++ = strlen(cp->cp_ifname);
                p = (char *)lenp;
                memcpy(p, cp->cp_ifname, strlen(cp->cp_ifname));
                p += strlen(cp->cp_ifname);
        } else {
                *lenp++ = '\0';
                p = (char *)lenp;
        }

        lenp = (size_t *)p;
        if (cp->cp_key != NULL) {
                *lenp++ = strlen(cp->cp_key);
                p = (char *)lenp;
                memcpy(p, cp->cp_key, strlen(cp->cp_key));
                p += strlen(cp->cp_key);
        } else {
                *lenp++ = '\0';
                p = (char *)lenp;
        }

        lenp = (size_t *)p;
        if (cp->cp_val != NULL && cp->cp_val_len > 0) {
                *lenp++ = cp->cp_val_len;
                p = (char *)lenp;
                memcpy(p, cp->cp_val, cp->cp_val_len);
                p += cp->cp_val_len;
        } else {
                *lenp++ = '\0';
                p = (char *)lenp;
        }

        return (len);
}

size_t
cm_str2bin(char *bin, void *str, size_t len)
{
        struct ctrl_msg_hdr *cm;

        syslog(LOG_DEBUG, "<%s> enter", __func__);

        if (len > CM_MSG_MAXLEN - sizeof(*cm)) {
                syslog(LOG_DEBUG, "<%s> msg too long (len=%zu)",
                    __func__, len);
                return (0);
        }
        syslog(LOG_DEBUG, "<%s> msglen=%zu", __func__, len);
        memcpy(bin, (char *)str, len);

        return (len);
}

void *
cm_bin2str(char *bin, void *str, size_t len)
{

        syslog(LOG_DEBUG, "<%s> enter", __func__);

        memcpy((char *)str, bin, len);

        return (str);
}