/* Copyright (c) 2008 Victor Julien <victor@inliniac.net> */

/* alert unified
 *
 * Logs alerts in a format compatible to Snort's unified1 format, so it should
 * be readable by Barnyard.
 *
 * TODO
 * - inspect error messages for threadsafety
 * - inspect gettimeofday for threadsafely
 * - implement configuration
 *
 */

#include "suricata-common.h"
#include "debug.h"
#include "detect.h"
#include "flow.h"
#include "conf.h"

#include "threads.h"
#include "threadvars.h"
#include "tm-modules.h"

#include "util-unittest.h"
#include "util-time.h"

#define DEFAULT_LOG_FILENAME "unified.log"

TmEcode AlertUnifiedLog (ThreadVars *, Packet *, void *, PacketQueue *);
TmEcode AlertUnifiedLogThreadInit(ThreadVars *, void *, void **);
TmEcode AlertUnifiedLogThreadDeinit(ThreadVars *, void *);
int AlertUnifiedLogOpenFileCtx(LogFileCtx *, char *);
void AlertUnifiedLogRegisterTests(void);

void TmModuleAlertUnifiedLogRegister (void) {
    tmm_modules[TMM_ALERTUNIFIEDLOG].name = "AlertUnifiedLog";
    tmm_modules[TMM_ALERTUNIFIEDLOG].ThreadInit = AlertUnifiedLogThreadInit;
    tmm_modules[TMM_ALERTUNIFIEDLOG].Func = AlertUnifiedLog;
    tmm_modules[TMM_ALERTUNIFIEDLOG].ThreadDeinit = AlertUnifiedLogThreadDeinit;
    tmm_modules[TMM_ALERTUNIFIEDLOG].RegisterTests = AlertUnifiedLogRegisterTests;
}

typedef struct AlertUnifiedLogThread_ {
    /** LogFileCtx has the pointer to the file and a mutex to allow multithreading */
    LogFileCtx* file_ctx;
    uint32_t size_limit;
    uint32_t size_current;
} AlertUnifiedLogThread;

#define ALERTUNIFIEDLOG_LOGMAGIC 0xDEAD1080 /* taken from Snort */
#define ALERTUNIFIEDLOG_VERMAJOR 1          /* taken from Snort */
#define ALERTUNIFIEDLOG_VERMINOR 2          /* taken from Snort */

typedef struct AlertUnifiedLogFileHeader_ {
    uint32_t magic;
    uint16_t ver_major;
    uint16_t ver_minor;
    uint32_t timezone;
    uint32_t pad1; /* Snort has something called sigfigs, dunno what it is. I do know it's always 0. */
    uint32_t snaplen;
    uint32_t linktype;
} AlertUnifiedLogFileHeader;

typedef struct AlertUnifiedLogPacketHeader_ {
    /* Snort's 'Event' structure */
    uint32_t sig_gen;
    uint32_t sig_sid;
    uint32_t sig_rev;
    uint32_t sig_class;
    uint32_t sig_prio;
    uint32_t pad1; /* Snort's event_id */
    uint32_t pad2; /* Snort's event_reference */
    uint32_t tv_sec1; /* from Snort's struct pcap_timeval */
    uint32_t tv_usec1; /* from Snort's struct pcap_timeval */

    /* 32 bit unsigned flags */
    uint32_t pktflags;

    /* Snort's 'SnortPktHeader' structure */
    uint32_t tv_sec2; /* from Snort's struct pcap_timeval */
    uint32_t tv_usec2; /* from Snort's struct pcap_timeval */
    uint32_t caplen;
    uint32_t pktlen;
} AlertUnifiedLogPacketHeader;

int AlertUnifiedLogWriteFileHeader(ThreadVars *t, AlertUnifiedLogThread *aun) {
    int ret;
    /* write the fileheader to the file so the reader can recognize it */

    AlertUnifiedLogFileHeader hdr;
    hdr.magic = ALERTUNIFIEDLOG_LOGMAGIC;
    hdr.ver_major = ALERTUNIFIEDLOG_VERMAJOR;
    hdr.ver_minor = ALERTUNIFIEDLOG_VERMINOR;
    hdr.timezone = 0; /* XXX */
    hdr.pad1 = 0; /* XXX */
    hdr.snaplen = 65536; /* XXX */
    hdr.linktype = DLT_EN10MB; /* XXX */

    ret = fwrite(&hdr, sizeof(hdr), 1, aun->file_ctx->fp);
    if (ret != 1) {
        printf("Error: fwrite failed: ret = %" PRId32 ", %s\n", ret, strerror(errno));
        return -1;
    }

    aun->size_current = sizeof(hdr);
    return 0;
}

int AlertUnifiedLogCloseFile(ThreadVars *t, AlertUnifiedLogThread *aun) {
    if (aun->file_ctx->fp != NULL) {
        fclose(aun->file_ctx->fp);
    }
    aun->size_current = 0;
    return 0;
}

int AlertUnifiedLogRotateFile(ThreadVars *t, AlertUnifiedLogThread *aun) {
    if (AlertUnifiedLogCloseFile(t,aun) < 0) {
        printf("Error: AlertUnifiedLogCloseFile failed\n");
        return -1;
    }
    if (AlertUnifiedLogOpenFileCtx(aun->file_ctx,aun->file_ctx->config_file) < 0) {
        printf("Error: AlertUnifiedLogOpenFileCtx, open new log file failed\n");
        return -1;
    }
    if (AlertUnifiedLogWriteFileHeader(t, aun) < 0) {
        printf("Error: AlertUnifiedLogAppendFile, write unified header failed\n");
        return -1;
    }
    return 0;
}

TmEcode AlertUnifiedLog (ThreadVars *tv, Packet *p, void *data, PacketQueue *pq)
{
    AlertUnifiedLogThread *aun = (AlertUnifiedLogThread *)data;
    AlertUnifiedLogPacketHeader hdr;
    int ret;
    uint8_t ethh_offset = 0;
    uint8_t buf[80000];
    uint32_t buflen = 0;

    /* the unified1 format only supports IPv4. */
    if (p->alerts.cnt == 0 || !PKT_IS_IPV4(p))
        return TM_ECODE_OK;

    /* if we have no ethernet header (e.g. when using nfq), we have to create
     * one ourselves. */
    if (p->ethh == NULL) {
        ethh_offset = sizeof(EthernetHdr);
    }

    /* check and enforce the filesize limit */
    /** Wait for the mutex. We dont want all the threads rotating the file
     * at the same time :) */
    SCMutexLock(&aun->file_ctx->fp_mutex);
    if ((aun->size_current + sizeof(hdr) + p->pktlen + ethh_offset) > aun->size_limit) {
        if (AlertUnifiedLogRotateFile(tv,aun) < 0)
        {
            SCMutexUnlock(&aun->file_ctx->fp_mutex);
            return TM_ECODE_FAILED;
        }
    }
    SCMutexUnlock(&aun->file_ctx->fp_mutex);

    /* XXX which one to add to this alert? Lets see how Snort solves this.
     * For now just take last alert. */
    PacketAlert *pa = &p->alerts.alerts[p->alerts.cnt-1];

    /* fill the hdr structure */
    hdr.sig_gen = pa->gid;
    hdr.sig_sid = pa->sid;
    hdr.sig_rev = pa->rev;
    hdr.sig_class = pa->class;
    hdr.sig_prio = pa->prio;
    hdr.pad1 = 0;
    hdr.pad2 = 0;
    hdr.tv_sec1 = hdr.tv_sec2 = p->ts.tv_sec;
    hdr.tv_usec1 = hdr.tv_usec2 = p->ts.tv_usec;
    hdr.pktflags = 0; /* XXX */
    hdr.pktlen = hdr.caplen = p->pktlen + ethh_offset;

    memcpy(buf,&hdr,sizeof(hdr));
    buflen = sizeof(hdr);

    if (p->ethh == NULL) {
        EthernetHdr ethh;
        memset(&ethh, 0, sizeof(EthernetHdr));
        ethh.eth_type = htons(ETHERNET_TYPE_IP);

        memcpy(buf+buflen,&ethh,sizeof(ethh));
        buflen += sizeof(ethh);
    }

    memcpy(buf+buflen,&p->pkt,p->pktlen);
    buflen += p->pktlen;

    /** write and flush so it's written immediately, no need to lock her, no need to lock heree */
    ret = fwrite(buf, buflen, 1, aun->file_ctx->fp);
    if (ret != 1) {
        printf("Error: fwrite failed: %s\n", strerror(errno));
        return TM_ECODE_FAILED;
    }
    /* force writing to disk so barnyard will not read half
     * written records and choke. */
    fflush(aun->file_ctx->fp);

    aun->size_current += buflen;
    return TM_ECODE_OK;
}

TmEcode AlertUnifiedLogThreadInit(ThreadVars *t, void *initdata, void **data)
{
    AlertUnifiedLogThread *aun = malloc(sizeof(AlertUnifiedLogThread));
    if (aun == NULL) {
        return TM_ECODE_FAILED;
    }
    memset(aun, 0, sizeof(AlertUnifiedLogThread));
    if(initdata == NULL)
    {
        printf("Error getting context for the file\n");
        return TM_ECODE_FAILED;
    }
    /** Use the Ouptut Context (file pointer and mutex) */
    aun->file_ctx = (LogFileCtx*) initdata;

    /** Write Unified header */
    int ret = AlertUnifiedLogWriteFileHeader(t, aun);
    if (ret != 0) {
        printf("Error: AlertUnifiedLogWriteFileHeader failed.\n");
        return TM_ECODE_FAILED;
    }

    /* XXX make configurable */
    aun->size_limit = 1 * 1024 * 1024;

    *data = (void *)aun;
    return TM_ECODE_OK;
}

TmEcode AlertUnifiedLogThreadDeinit(ThreadVars *t, void *data)
{
    AlertUnifiedLogThread *aun = (AlertUnifiedLogThread *)data;
    if (aun == NULL) {
        goto error;
    }

    /* clear memory */
    memset(aun, 0, sizeof(AlertUnifiedLogThread));
    free(aun);
    return TM_ECODE_OK;

error:
    /* clear memory */
    if (aun != NULL) {
        memset(aun, 0, sizeof(AlertUnifiedLogThread));
        free(aun);
    }
    printf("AlertUnifiedLogThreadDeinit done (error)\n");
    return TM_ECODE_FAILED;
}


/** \brief Create a new file_ctx from config_file (if specified)
 *  \param config_file for loading separate configs
 *  \return NULL if failure, LogFileCtx* to the file_ctx if succesful
 * */
LogFileCtx *AlertUnifiedLogInitCtx(char *config_file)
{
    int ret=0;
    LogFileCtx* file_ctx=LogFileNewCtx();

    if(file_ctx == NULL)
    {
        printf("AlertUnifiedLogInitCtx: Couldn't create new file_ctx\n");
        return NULL;
    }

    /** fill the new LogFileCtx with the specific AlertUnifiedLog configuration */
    ret=AlertUnifiedLogOpenFileCtx(file_ctx, config_file);

    if(ret < 0)
        return NULL;

    /** In AlertUnifiedLogOpenFileCtx the second parameter should be the configuration file to use
    * but it's not implemented yet, so passing NULL to load the default
    * configuration
    */

    return file_ctx;
}

/** \brief Read the config set the file pointer, open the file
 *  \param file_ctx pointer to a created LogFileCtx using LogFileNewCtx()
 *  \param config_file for loading separate configs
 *  \return -1 if failure, 0 if succesful
 * */
int AlertUnifiedLogOpenFileCtx(LogFileCtx *file_ctx, char *config_file)
{
    char *filename = NULL;
    if (file_ctx->filename != NULL)
        filename = file_ctx->filename;
    else
        filename = file_ctx->filename = malloc(PATH_MAX); /* XXX some sane default? */

    if(config_file == NULL)
    {
        /** Separate config files not implemented at the moment,
        * but it must be able to load from separate config file.
        * Load the default configuration.
        */

        /* get the time so we can have a filename with seconds since epoch */
        struct timeval ts;
        memset (&ts, 0, sizeof(struct timeval));
        TimeGet(&ts);

        /* create the filename to use */
        char *log_dir;
        if (ConfGet("default-log-dir", &log_dir) != 1)
            log_dir = DEFAULT_LOG_DIR;

        snprintf(filename, PATH_MAX, "%s/%s.%" PRIu32, log_dir, "unified.log", (uint32_t)ts.tv_sec);

        /* XXX filename & location */
        file_ctx->fp = fopen(filename, "wb");
        if (file_ctx->fp == NULL) {
            printf("Error: fopen %s failed: %s\n", filename, strerror(errno)); /* XXX errno threadsafety? */
            return -1;
        }
    }

    return 0;
}

#ifdef UNITTESTS
/**
 *  \test Test the Rotate process
 *
 *  \retval 1 on succces
 *  \retval 0 on failure
 */
static int AlertUnifiedLogTestRotate01(void)
{
    int ret = 0;
    int r = 0;
    ThreadVars tv;
    LogFileCtx *lf;
    void *data = NULL;

    lf = AlertUnifiedLogInitCtx(NULL);
    char *filename = strdup(lf->filename);

    memset(&tv, 0, sizeof(ThreadVars));

    if (lf == NULL)
        return 0;

    ret = AlertUnifiedLogThreadInit(&tv, lf, &data);
    if (ret == TM_ECODE_FAILED) {
        LogFileFreeCtx(lf);
        return 0;
    }

    TimeSetIncrementTime(1);

    ret = AlertUnifiedLogRotateFile(&tv, data);
    if (ret == -1)
        goto error;

    if (strcmp(filename, lf->filename) == 0)
        goto error;

    r = 1;

error:
    AlertUnifiedLogThreadDeinit(&tv, data);
    if (lf != NULL) LogFileFreeCtx(lf);
    if (filename != NULL) free(filename);
    return r;
}
#endif /* UNITTESTS */

/**
 * \brief this function registers unit tests for Unified2
 */
void AlertUnifiedLogRegisterTests (void) {
#ifdef UNITTESTS
    UtRegisterTest("UnifiedAlertTestRotate01 -- Rotate File",
                   AlertUnifiedLogTestRotate01, 1);
#endif /* UNITTESTS */
}