#include "ipf.h"
#include "netinet/ipl.h"
#include "ipmon.h"
#include <ctype.h>

#define IPF_ENTERPRISE  9932
/*
 * Enterprise number OID:
 * 1.3.6.1.4.1.9932
 */
static u_char ipf_enterprise[] = { 6, 7, 0x2b, 6, 1, 4, 1, 0xcd, 0x4c };
static u_char ipf_trap0_1[] = { 6, 10, 0x2b, 6, 1, 4, 1, 0xcd, 0x4c, 1, 1, 1 };
static u_char ipf_trap0_2[] = { 6, 10, 0x2b, 6, 1, 4, 1, 0xcd, 0x4c, 1, 1, 2 };

static int writeint(u_char *, int);
static int writelength(u_char *, u_int);
static int maketrap_v1(char *, u_char *, int, u_char *, int, u_32_t,
                            time_t);
static void snmpv1_destroy(void *);
static void *snmpv1_dup(void *);
static int snmpv1_match(void *, void *);
static void *snmpv1_parse(char **);
static void snmpv1_print(void *);
static int snmpv1_send(void *, ipmon_msg_t *);

typedef struct snmpv1_opts_s {
        char                    *community;
        int                     fd;
        int                     v6;
        int                     ref;
#ifdef USE_INET6
        struct sockaddr_in6     sin6;
#endif
        struct sockaddr_in      sin;
} snmpv1_opts_t;

ipmon_saver_t snmpv1saver = {
        "snmpv1",
        snmpv1_destroy,
        snmpv1_dup,             /* dup */
        snmpv1_match,           /* match */
        snmpv1_parse,
        snmpv1_print,
        snmpv1_send
};


static int
snmpv1_match(void *ctx1, void *ctx2)
{
        snmpv1_opts_t *s1 = ctx1, *s2 = ctx2;

        if (s1->v6 != s2->v6)
                return (1);

        if (strcmp(s1->community, s2->community))
                return (1);

#ifdef USE_INET6
        if (s1->v6 == 1) {
                if (memcmp(&s1->sin6, &s2->sin6, sizeof(s1->sin6)))
                        return (1);
        } else
#endif
        {
                if (memcmp(&s1->sin, &s2->sin, sizeof(s1->sin)))
                        return (1);
        }

        return (0);
}


static void *
snmpv1_dup(void *ctx)
{
        snmpv1_opts_t *s = ctx;

        s->ref++;
        return (s);
}


static void
snmpv1_print(void *ctx)
{
        snmpv1_opts_t *snmpv1 = ctx;

        printf("%s ", snmpv1->community);
#ifdef USE_INET6
        if (snmpv1->v6 == 1) {
                char buf[80];

                printf("%s", inet_ntop(AF_INET6, &snmpv1->sin6.sin6_addr, buf,
                                       sizeof(snmpv1->sin6.sin6_addr)));
        } else
#endif
        {
                printf("%s", inet_ntoa(snmpv1->sin.sin_addr));
        }
}


static void *
snmpv1_parse(char **strings)
{
        snmpv1_opts_t *ctx;
        int result;
        char *str;
        char *s;

        if (strings[0] == NULL || strings[0][0] == '\0')
                return (NULL);

        if (strchr(*strings, ' ') == NULL)
                return (NULL);

        str = strdup(*strings);

        ctx = calloc(1, sizeof(*ctx));
        if (ctx == NULL)
                return (NULL);

        ctx->fd = -1;

        s = strchr(str, ' ');
        *s++ = '\0';
        ctx->community = str;

        while (ISSPACE(*s))
                s++;
        if (!*s) {
                free(str);
                free(ctx);
                return (NULL);
        }

#ifdef USE_INET6
        if (strchr(s, ':') == NULL) {
                result = inet_pton(AF_INET, s, &ctx->sin.sin_addr);
                if (result == 1) {
                        ctx->fd = socket(AF_INET, SOCK_DGRAM, 0);
                        if (ctx->fd >= 0) {
                                ctx->sin.sin_family = AF_INET;
                                ctx->sin.sin_port = htons(162);
                                if (connect(ctx->fd,
                                            (struct sockaddr *)&ctx->sin,
                                            sizeof(ctx->sin)) != 0) {
                                                snmpv1_destroy(ctx);
                                                return (NULL);
                                }
                        }
                }
        } else {
                result = inet_pton(AF_INET6, s, &ctx->sin6.sin6_addr);
                if (result == 1) {
                        ctx->v6 = 1;
                        ctx->fd = socket(AF_INET6, SOCK_DGRAM, 0);
                        if (ctx->fd >= 0) {
                                ctx->sin6.sin6_family = AF_INET6;
                                ctx->sin6.sin6_port = htons(162);
                                if (connect(ctx->fd,
                                            (struct sockaddr *)&ctx->sin6,
                                            sizeof(ctx->sin6)) != 0) {
                                                snmpv1_destroy(ctx);
                                                return (NULL);
                                }
                        }
                }
        }
#else
        result = inet_aton(s, &ctx->sin.sin_addr);
        if (result == 1) {
                ctx->fd = socket(AF_INET, SOCK_DGRAM, 0);
                if (ctx->fd >= 0) {
                        ctx->sin.sin_family = AF_INET;
                        ctx->sin.sin_port = htons(162);
                        if (connect(ctx->fd, (struct sockaddr *)&ctx->sin,
                                    sizeof(ctx->sin)) != 0) {
                                        snmpv1_destroy(ctx);
                                        return (NULL);
                        }
                }
        }
#endif

        if (result != 1) {
                free(str);
                free(ctx);
                return (NULL);
        }

        ctx->ref = 1;

        return (ctx);
}


static void
snmpv1_destroy(void *ctx)
{
        snmpv1_opts_t *v1 = ctx;

        v1->ref--;
        if (v1->ref > 0)
                return;

        if (v1->community)
                free(v1->community);
        if (v1->fd >= 0)
                close(v1->fd);
        free(v1);
}


static int
snmpv1_send(void *ctx, ipmon_msg_t *msg)
{
        snmpv1_opts_t *v1 = ctx;

        return (sendtrap_v1_0(v1->fd, v1->community,
                             msg->imm_msg, msg->imm_msglen, msg->imm_when));
}

static char def_community[] = "public"; /* ublic */

static int
writelength(u_char *buffer, u_int value)
{
        u_int n = htonl(value);
        int len;

        if (value < 128) {
                *buffer = value;
                return (1);
        }
        if (value > 0xffffff)
                len = 4;
        else if (value > 0xffff)
                len = 3;
        else if (value > 0xff)
                len = 2;
        else
                len = 1;

        *buffer = 0x80 | len;

        bcopy((u_char *)&n + 4 - len, buffer + 1, len);

        return (len + 1);
}


static int
writeint(u_char *buffer, int value)
{
        u_char *s = buffer;
        u_int n = value;

        if (value == 0) {
                *buffer = 0;
                return (1);
        }

        if (n >  4194304) {
                *s++ = 0x80 | (n / 4194304);
                n -= 4194304 * (n / 4194304);
        }
        if (n >  32768) {
                *s++ = 0x80 | (n / 32768);
                n -= 32768 * (n / 327678);
        }
        if (n > 128) {
                *s++ = 0x80 | (n / 128);
                n -= (n / 128) * 128;
        }
        *s++ = (u_char)n;

        return (s - buffer);
}



/*
 * First style of traps is:
 * 1.3.6.1.4.1.9932.1.1
 */
static int
maketrap_v1(char *community, u_char *buffer, int bufsize, u_char *msg,
        int msglen, u_32_t ipaddr, time_t when)
{
        u_char *s = buffer, *t, *pdulen, *varlen;
        int basesize = 73;
        u_short len;
        int trapmsglen;
        int pdulensz;
        int varlensz;
        int baselensz;
        int n;

        if (community == NULL || *community == '\0')
                community = def_community;
        basesize += strlen(community) + msglen;

        if (basesize + 8 > bufsize)
                return (0);

        memset(buffer, 0xff, bufsize);
        *s++ = 0x30;            /* Sequence */
        if (basesize - 1 >= 128) {
                baselensz = 2;
                basesize++;
        } else {
                baselensz = 1;
        }
        s += baselensz;
        *s++ = 0x02;            /* Integer32 */
        *s++ = 0x01;            /* length 1 */
        *s++ = 0x00;            /* version 1 */
        *s++ = 0x04;            /* octet string */
        *s++ = strlen(community);               /* length of "public" */
        bcopy(community, s, s[-1]);
        s += s[-1];
        *s++ = 0xA4;            /* PDU(4) */
        pdulen = s++;
        if (basesize - (s - buffer) >= 128) {
                pdulensz = 2;
                basesize++;
                s++;
        } else {
                pdulensz = 1;
        }

        /* enterprise */
        bcopy(ipf_enterprise, s, sizeof(ipf_enterprise));
        s += sizeof(ipf_enterprise);

        /* Agent address */
        *s++ = 0x40;
        *s++ = 0x4;
        bcopy(&ipaddr, s, 4);
        s += 4;

        /* Generic Trap code */
        *s++ = 0x2;
        n = writeint(s + 1, 6);
        if (n == 0)
                return (0);
        *s = n;
        s += n + 1;

        /* Specific Trap code */
        *s++ = 0x2;
        n = writeint(s + 1, 0);
        if (n == 0)
                return (0);
        *s = n;
        s += n + 1;

        /* Time stamp */
        *s++ = 0x43;                    /* TimeTicks */
        *s++ = 0x04;                    /* TimeTicks */
        s[0] = when >> 24;
        s[1] = when >> 16;
        s[2] = when >> 8;
        s[3] = when & 0xff;
        s += 4;

        /*
         * The trap0 message is "ipfilter_version" followed by the message
         */
        *s++ = 0x30;
        varlen = s;
        if (basesize - (s - buffer) >= 128) {
                varlensz = 2;
                basesize++;
        } else {
                varlensz = 1;
        }
        s += varlensz;

        *s++ = 0x30;
        t = s + 1;
        bcopy(ipf_trap0_1, t, sizeof(ipf_trap0_1));
        t += sizeof(ipf_trap0_1);

        *t++ = 0x2;             /* Integer */
        n = writeint(t + 1, IPFILTER_VERSION);
        *t = n;
        t += n + 1;

        len = t - s - 1;
        writelength(s, len);

        s = t;
        *s++ = 0x30;
        if (basesize - (s - buffer) >= 128) {
                trapmsglen = 2;
                basesize++;
        } else {
                trapmsglen = 1;
        }
        t = s + trapmsglen;
        bcopy(ipf_trap0_2, t, sizeof(ipf_trap0_2));
        t += sizeof(ipf_trap0_2);

        *t++ = 0x4;             /* Octet string */
        n = writelength(t, msglen);
        t += n;
        bcopy(msg, t, msglen);
        t += msglen;

        len = t - s - trapmsglen;
        writelength(s, len);

        len = t - varlen - varlensz;
        writelength(varlen, len);               /* pdu length */

        len = t - pdulen - pdulensz;
        writelength(pdulen, len);               /* pdu length */

        len = t - buffer - baselensz - 1;
        writelength(buffer + 1, len);   /* length of trap */

        return (t - buffer);
}


int
sendtrap_v1_0(int fd, char *community, char *msg, int msglen, time_t when)
{

        u_char buffer[1500];
        int n;

        n = maketrap_v1(community, buffer, sizeof(buffer),
                        (u_char *)msg, msglen, 0, when);
        if (n > 0) {
                return (send(fd, buffer, n, 0));
        }

        return (0);
}