/*
 * An implementation of key value pair (KVP) functionality for Linux.
 *
 *
 * Copyright (C) 2010, Novell, Inc.
 * Author : K. Y. Srinivasan <ksrinivasan@novell.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 * NON INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */


#include <sys/types.h>
#include <sys/socket.h>
#include <sys/poll.h>
#include <sys/utsname.h>
#include <linux/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <arpa/inet.h>
#include <linux/connector.h>
#include <linux/netlink.h>
#include <ifaddrs.h>
#include <netdb.h>
#include <syslog.h>

/*
 * KYS: TODO. Need to register these in the kernel.
 *
 * The following definitions are shared with the in-kernel component; do not
 * change any of this without making the corresponding changes in
 * the KVP kernel component.
 */
#define CN_KVP_IDX              0x9     /* MSFT KVP functionality */
#define CN_KVP_VAL              0x1 /* This supports queries from the kernel */
#define CN_KVP_USER_VAL         0x2 /* This supports queries from the user  */

/*
 * KVP protocol: The user mode component first registers with the
 * the kernel component. Subsequently, the kernel component requests, data
 * for the specified keys. In response to this message the user mode component
 * fills in the value corresponding to the specified key. We overload the
 * sequence field in the cn_msg header to define our KVP message types.
 *
 * We use this infrastructure for also supporting queries from user mode
 * application for state that may be maintained in the KVP kernel component.
 *
 * XXXKYS: Have a shared header file between the user and kernel (TODO)
 */

enum kvp_op {
        KVP_REGISTER = 0, /* Register the user mode component*/
        KVP_KERNEL_GET, /*Kernel is requesting the value for the specified key*/
        KVP_KERNEL_SET, /*Kernel is providing the value for the specified key*/
        KVP_USER_GET, /*User is requesting the value for the specified key*/
        KVP_USER_SET /*User is providing the value for the specified key*/
};

#define HV_KVP_EXCHANGE_MAX_KEY_SIZE    512
#define HV_KVP_EXCHANGE_MAX_VALUE_SIZE  2048

struct hv_ku_msg {
        __u32   kvp_index;
        __u8  kvp_key[HV_KVP_EXCHANGE_MAX_KEY_SIZE]; /* Key name */
        __u8  kvp_value[HV_KVP_EXCHANGE_MAX_VALUE_SIZE]; /* Key  value */
};

enum key_index {
        FullyQualifiedDomainName = 0,
        IntegrationServicesVersion, /*This key is serviced in the kernel*/
        NetworkAddressIPv4,
        NetworkAddressIPv6,
        OSBuildNumber,
        OSName,
        OSMajorVersion,
        OSMinorVersion,
        OSVersion,
        ProcessorArchitecture
};

/*
 * End of shared definitions.
 */

static char kvp_send_buffer[4096];
static char kvp_recv_buffer[4096];
static struct sockaddr_nl addr;

static char *os_name = "";
static char *os_major = "";
static char *os_minor = "";
static char *processor_arch;
static char *os_build;
static char *lic_version;
static struct utsname uts_buf;

void kvp_get_os_info(void)
{
        FILE    *file;
        char    *p, buf[512];

        uname(&uts_buf);
        os_build = uts_buf.release;
        processor_arch = uts_buf.machine;

        /*
         * The current windows host (win7) expects the build
         * string to be of the form: x.y.z
         * Strip additional information we may have.
         */
        p = strchr(os_build, '-');
        if (p)
                *p = '\0';

        file = fopen("/etc/SuSE-release", "r");
        if (file != NULL)
                goto kvp_osinfo_found;
        file  = fopen("/etc/redhat-release", "r");
        if (file != NULL)
                goto kvp_osinfo_found;
        /*
         * Add code for other supported platforms.
         */

        /*
         * We don't have information about the os.
         */
        os_name = uts_buf.sysname;
        return;

kvp_osinfo_found:
        /* up to three lines */
        p = fgets(buf, sizeof(buf), file);
        if (p) {
                p = strchr(buf, '\n');
                if (p)
                        *p = '\0';
                p = strdup(buf);
                if (!p)
                        goto done;
                os_name = p;

                /* second line */
                p = fgets(buf, sizeof(buf), file);
                if (p) {
                        p = strchr(buf, '\n');
                        if (p)
                                *p = '\0';
                        p = strdup(buf);
                        if (!p)
                                goto done;
                        os_major = p;

                        /* third line */
                        p = fgets(buf, sizeof(buf), file);
                        if (p)  {
                                p = strchr(buf, '\n');
                                if (p)
                                        *p = '\0';
                                p = strdup(buf);
                                if (p)
                                        os_minor = p;
                        }
                }
        }

done:
        fclose(file);
        return;
}

static int
kvp_get_ip_address(int family, char *buffer, int length)
{
        struct ifaddrs *ifap;
        struct ifaddrs *curp;
        int ipv4_len = strlen("255.255.255.255") + 1;
        int ipv6_len = strlen("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff")+1;
        int offset = 0;
        const char *str;
        char tmp[50];
        int error = 0;

        /*
         * On entry into this function, the buffer is capable of holding the
         * maximum key value (2048 bytes).
         */

        if (getifaddrs(&ifap)) {
                strcpy(buffer, "getifaddrs failed\n");
                return 1;
        }

        curp = ifap;
        while (curp != NULL) {
                if ((curp->ifa_addr != NULL) &&
                   (curp->ifa_addr->sa_family == family)) {
                        if (family == AF_INET) {
                                struct sockaddr_in *addr =
                                (struct sockaddr_in *) curp->ifa_addr;

                                str = inet_ntop(family, &addr->sin_addr,
                                                tmp, 50);
                                if (str == NULL) {
                                        strcpy(buffer, "inet_ntop failed\n");
                                        error = 1;
                                        goto getaddr_done;
                                }
                                if (offset == 0)
                                        strcpy(buffer, tmp);
                                else
                                        strcat(buffer, tmp);
                                strcat(buffer, ";");

                                offset += strlen(str) + 1;
                                if ((length - offset) < (ipv4_len + 1))
                                        goto getaddr_done;

                        } else {

                        /*
                         * We only support AF_INET and AF_INET6
                         * and the list of addresses is separated by a ";".
                         */
                                struct sockaddr_in6 *addr =
                                (struct sockaddr_in6 *) curp->ifa_addr;

                                str = inet_ntop(family,
                                        &addr->sin6_addr.s6_addr,
                                        tmp, 50);
                                if (str == NULL) {
                                        strcpy(buffer, "inet_ntop failed\n");
                                        error = 1;
                                        goto getaddr_done;
                                }
                                if (offset == 0)
                                        strcpy(buffer, tmp);
                                else
                                        strcat(buffer, tmp);
                                strcat(buffer, ";");
                                offset += strlen(str) + 1;
                                if ((length - offset) < (ipv6_len + 1))
                                        goto getaddr_done;

                        }

                }
                curp = curp->ifa_next;
        }

getaddr_done:
        freeifaddrs(ifap);
        return error;
}


static int
kvp_get_domain_name(char *buffer, int length)
{
        struct addrinfo hints, *info ;
        int error = 0;

        gethostname(buffer, length);
        memset(&hints, 0, sizeof(hints));
        hints.ai_family = AF_INET; /*Get only ipv4 addrinfo. */
        hints.ai_socktype = SOCK_STREAM;
        hints.ai_flags = AI_CANONNAME;

        error = getaddrinfo(buffer, NULL, &hints, &info);
        if (error != 0) {
                strcpy(buffer, "getaddrinfo failed\n");
                return error;
        }
        strcpy(buffer, info->ai_canonname);
        freeaddrinfo(info);
        return error;
}

static int
netlink_send(int fd, struct cn_msg *msg)
{
        struct nlmsghdr *nlh;
        unsigned int size;
        struct msghdr message;
        char buffer[64];
        struct iovec iov[2];

        size = NLMSG_SPACE(sizeof(struct cn_msg) + msg->len);

        nlh = (struct nlmsghdr *)buffer;
        nlh->nlmsg_seq = 0;
        nlh->nlmsg_pid = getpid();
        nlh->nlmsg_type = NLMSG_DONE;
        nlh->nlmsg_len = NLMSG_LENGTH(size - sizeof(*nlh));
        nlh->nlmsg_flags = 0;

        iov[0].iov_base = nlh;
        iov[0].iov_len = sizeof(*nlh);

        iov[1].iov_base = msg;
        iov[1].iov_len = size;

        memset(&message, 0, sizeof(message));
        message.msg_name = &addr;
        message.msg_namelen = sizeof(addr);
        message.msg_iov = iov;
        message.msg_iovlen = 2;

        return sendmsg(fd, &message, 0);
}

int main(void)
{
        int fd, len, sock_opt;
        int error;
        struct cn_msg *message;
        struct pollfd pfd;
        struct nlmsghdr *incoming_msg;
        struct cn_msg   *incoming_cn_msg;
        struct hv_ku_msg *hv_msg;
        char    *p;
        char    *key_value;
        char    *key_name;

        daemon(1, 0);
        openlog("KVP", 0, LOG_USER);
        syslog(LOG_INFO, "KVP starting; pid is:%d", getpid());
        /*
         * Retrieve OS release information.
         */
        kvp_get_os_info();

        fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
        if (fd < 0) {
                syslog(LOG_ERR, "netlink socket creation failed; error:%d", fd);
                exit(-1);
        }
        addr.nl_family = AF_NETLINK;
        addr.nl_pad = 0;
        addr.nl_pid = 0;
        addr.nl_groups = CN_KVP_IDX;


        error = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
        if (error < 0) {
                syslog(LOG_ERR, "bind failed; error:%d", error);
                close(fd);
                exit(-1);
        }
        sock_opt = addr.nl_groups;
        setsockopt(fd, 270, 1, &sock_opt, sizeof(sock_opt));
        /*
         * Register ourselves with the kernel.
         */
        message = (struct cn_msg *)kvp_send_buffer;
        message->id.idx = CN_KVP_IDX;
        message->id.val = CN_KVP_VAL;
        message->seq = KVP_REGISTER;
        message->ack = 0;
        message->len = 0;

        len = netlink_send(fd, message);
        if (len < 0) {
                syslog(LOG_ERR, "netlink_send failed; error:%d", len);
                close(fd);
                exit(-1);
        }

        pfd.fd = fd;

        while (1) {
                pfd.events = POLLIN;
                pfd.revents = 0;
                poll(&pfd, 1, -1);

                len = recv(fd, kvp_recv_buffer, sizeof(kvp_recv_buffer), 0);

                if (len < 0) {
                        syslog(LOG_ERR, "recv failed; error:%d", len);
                        close(fd);
                        return -1;
                }

                incoming_msg = (struct nlmsghdr *)kvp_recv_buffer;
                incoming_cn_msg = (struct cn_msg *)NLMSG_DATA(incoming_msg);

                switch (incoming_cn_msg->seq) {
                case KVP_REGISTER:
                        /*
                         * Driver is registering with us; stash away the version
                         * information.
                         */
                        p = (char *)incoming_cn_msg->data;
                        lic_version = malloc(strlen(p) + 1);
                        if (lic_version) {
                                strcpy(lic_version, p);
                                syslog(LOG_INFO, "KVP LIC Version: %s",
                                        lic_version);
                        } else {
                                syslog(LOG_ERR, "malloc failed");
                        }
                        continue;

                case KVP_KERNEL_GET:
                        break;
                default:
                        continue;
                }

                hv_msg = (struct hv_ku_msg *)incoming_cn_msg->data;
                key_name = (char *)hv_msg->kvp_key;
                key_value = (char *)hv_msg->kvp_value;

                switch (hv_msg->kvp_index) {
                case FullyQualifiedDomainName:
                        kvp_get_domain_name(key_value,
                                        HV_KVP_EXCHANGE_MAX_VALUE_SIZE);
                        strcpy(key_name, "FullyQualifiedDomainName");
                        break;
                case IntegrationServicesVersion:
                        strcpy(key_name, "IntegrationServicesVersion");
                        strcpy(key_value, lic_version);
                        break;
                case NetworkAddressIPv4:
                        kvp_get_ip_address(AF_INET, key_value,
                                        HV_KVP_EXCHANGE_MAX_VALUE_SIZE);
                        strcpy(key_name, "NetworkAddressIPv4");
                        break;
                case NetworkAddressIPv6:
                        kvp_get_ip_address(AF_INET6, key_value,
                                        HV_KVP_EXCHANGE_MAX_VALUE_SIZE);
                        strcpy(key_name, "NetworkAddressIPv6");
                        break;
                case OSBuildNumber:
                        strcpy(key_value, os_build);
                        strcpy(key_name, "OSBuildNumber");
                        break;
                case OSName:
                        strcpy(key_value, os_name);
                        strcpy(key_name, "OSName");
                        break;
                case OSMajorVersion:
                        strcpy(key_value, os_major);
                        strcpy(key_name, "OSMajorVersion");
                        break;
                case OSMinorVersion:
                        strcpy(key_value, os_minor);
                        strcpy(key_name, "OSMinorVersion");
                        break;
                case OSVersion:
                        strcpy(key_value, os_build);
                        strcpy(key_name, "OSVersion");
                        break;
                case ProcessorArchitecture:
                        strcpy(key_value, processor_arch);
                        strcpy(key_name, "ProcessorArchitecture");
                        break;
                default:
                        strcpy(key_value, "Unknown Key");
                        /*
                         * We use a null key name to terminate enumeration.
                         */
                        strcpy(key_name, "");
                        break;
                }
                /*
                 * Send the value back to the kernel. The response is
                 * already in the receive buffer. Update the cn_msg header to
                 * reflect the key value that has been added to the message
                 */

                incoming_cn_msg->id.idx = CN_KVP_IDX;
                incoming_cn_msg->id.val = CN_KVP_VAL;
                incoming_cn_msg->seq = KVP_USER_SET;
                incoming_cn_msg->ack = 0;
                incoming_cn_msg->len = sizeof(struct hv_ku_msg);

                len = netlink_send(fd, incoming_cn_msg);
                if (len < 0) {
                        syslog(LOG_ERR, "net_link send failed; error:%d", len);
                        exit(-1);
                }
        }

}