/*
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms of version
 * 1.0 of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source.  A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 */

/*
 * Copyright (c) 2017 Joyent, Inc.
 */

/*
 * Designed to be backgrounded and just killed. Open a PF_KEY socket, do
 * an extended-REGISTER so the kernel will send extended-ACQUIRE messages,
 * and then read-and-discard everything off the socket.
 */

#include <sys/socket.h>
#include <net/pfkeyv2.h>
#include <stdio.h>
#include <errno.h>
#include <err.h>
#include <unistd.h>

/* ARGSUSED */
int
main(int argc, char *argv[])
{
        int s, rc;
        uint64_t buf[1024];     /* PF_KEY likes 64-bit alignment. */
        sadb_msg_t *samsg;
        sadb_x_ereg_t *ereg;
        boolean_t ah_ack, esp_ack;
        pid_t pid = getpid();

        s = socket(PF_KEY, SOCK_RAW, PF_KEY_V2);
        if (s == -1)
                err(-1, "socket(PF_KEY)");

        /* Base message. */
        samsg = (sadb_msg_t *)buf;
        ereg = (sadb_x_ereg_t *)(samsg + 1);
        samsg->sadb_msg_version = PF_KEY_V2;
        samsg->sadb_msg_type = SADB_REGISTER;
        samsg->sadb_msg_errno = 0;
        samsg->sadb_msg_satype = SADB_SATYPE_UNSPEC;
        samsg->sadb_msg_reserved = 0;
        samsg->sadb_msg_seq = 1;
        samsg->sadb_msg_pid = pid;
        samsg->sadb_msg_len = SADB_8TO64(sizeof (*samsg) + sizeof (*ereg));

        /* extended REGISTER so we can listen for extended ACQUIREs. */
        ereg->sadb_x_ereg_len = SADB_8TO64(sizeof (*ereg));
        ereg->sadb_x_ereg_exttype = SADB_X_EXT_EREG;
        ereg->sadb_x_ereg_satypes[0] = SADB_SATYPE_ESP;
        ereg->sadb_x_ereg_satypes[1] = SADB_SATYPE_AH;
        ereg->sadb_x_ereg_satypes[2] = SADB_SATYPE_UNSPEC;

        rc = write(s, buf, sizeof (*samsg) + sizeof (*ereg));
        if (rc == -1)
                err(-1, "Extended register write error");

        /*
         * Extended REGISTER expects a regular REGISTER reply for EACH protocol
         * requested.  In our case, AH and ESP.
         */
        do {

                do {
                        rc = read(s, buf, sizeof (buf));
                        if (rc == -1)
                                err(-1, "Extended register read error");

                } while (samsg->sadb_msg_seq != 1 ||
                    samsg->sadb_msg_pid != pid ||
                    samsg->sadb_msg_type != SADB_REGISTER);

                if (samsg->sadb_msg_errno != 0) {
                        if (samsg->sadb_msg_errno == EPROTONOSUPPORT) {
                                warn("Protocol %d not supported.",
                                    samsg->sadb_msg_satype);
                        } else {
                                errno = samsg->sadb_msg_errno;
                                err(-1, "Extended REGISTER returned");
                        }
                }

                switch (samsg->sadb_msg_satype) {
                case SADB_SATYPE_ESP:
                        esp_ack = B_TRUE;
                        break;
                case SADB_SATYPE_AH:
                        ah_ack = B_TRUE;
                        break;
                default:
                        err(-1, "Bad satype in extended register ACK %d.",
                            samsg->sadb_msg_satype);
                }
        } while (!esp_ack || !ah_ack);

        /* Expect this loop to never end. This program ends via signal. */
        do {
                rc = read(s, buf, sizeof (buf));
        } while (rc != -1);

        err(-1, "PF_KEY read error");
}