#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);
}