#include "global.h"
#include "exec.h"
#include "srv.h"


static void *
timeoutSession(sched_task_t *task)
{
	rpack_t *pkt = TASK_DATA(task);

	ETRACE();

	/* drop session */
	if (cli.fd > 2)
		close(cli.fd);
	rpack_resize(pkt, TFTP_PKT_MAX);
	memset(&cli, 0, sizeof cli);

	taskExit(task, NULL);
}

static void *
txPkt(sched_task_t *task)
{
	int wlen;
	rpack_t *pkt = TASK_DATA(task);
	struct tftp_hdr *tftp = (struct tftp_hdr*) RPACK_BUF(pkt);

	ETRACE();

	wlen = sendto(TASK_FD(task), RPACK_BUF(pkt), TASK_DATLEN(task), 
			0, &cli.addr.sa, cli.addr.sa.sa_len);
	if (wlen == -1)
		ESYSERR(0);
	else if (wlen != TASK_DATLEN(task)) {
		EERROR(EIO, "Sended %d bytes != packet %d bytes", 
				wlen, TASK_DATLEN(task));
		schedEvent(TASK_ROOT(task), execProg, "error", 0, NULL, TFTP_OPC_ERROR);
		schedCancelby(TASK_ROOT(task), taskTIMER, CRITERIA_CALL, 
				timeoutSession, NULL);
		schedEvent(TASK_ROOT(task), timeoutSession, NULL, 0, TASK_DATA(task), 0);
	} else
		EVERBOSE(2, "Sended %d bytes", wlen);
	/* on error or argument, drop session */
	if (TASK_ARG(task) == (void*) -1 || ntohs(tftp->tftp_opc) == TFTP_OPC_ERROR) {
		schedEvent(TASK_ROOT(task), execProg, "error", 0, NULL, TFTP_OPC_ERROR);
		schedCancelby(TASK_ROOT(task), taskTIMER, CRITERIA_CALL, 
				timeoutSession, NULL);
		schedEvent(TASK_ROOT(task), timeoutSession, NULL, 0, TASK_DATA(task), 0);
	}

	taskExit(task, NULL);
}

static void *
txData(sched_task_t *task)
{
	rpack_t *pkt = TASK_DATA(task);
	u_short code = 0, n = htons(TFTP_OPC_DATA);
	int len;

	ETRACE();

	RPACK_REWIND(pkt);
	rpack_uint16(pkt, &n, 0);
	n = htons(cli.seq);
	rpack_uint16(pkt, &n, 0);

	/* max file size check */
	if (cli.tsiz && cli.tsiz < cli.seq * cli.siz) {
		len = cli.tsiz - (cli.seq - 1) * cli.siz;
		cli.close = 42;	/* last sended packet, should be close! */
	} else
		len = cli.siz;

	len = pread(cli.fd, RPACK_NEXT(pkt), len, (cli.seq - 1) * cli.siz);
	if (len == -1) {
		ESYSERR(0);
		code = htole16(3);
		goto end;
	} else {
		rpack_rnext(pkt, len);
		EVERBOSE(3, "Read from file %s %d bytes", cli.file, len);
	}

	if (cli.siz - len)
		cli.close = 42;	/* last sended packet, should be close! */

	schedEvent(TASK_ROOT(task), txPkt, NULL, TASK_FD(task), 
			TASK_DATA(task), RPACK_OFF(pkt));
	taskExit(task, NULL);
end:
	RPACK_REWIND(pkt);
	n = htons(TFTP_OPC_ERROR);
	rpack_uint16(pkt, &n, 0);
	rpack_uint16(pkt, &code, 0);
	rpack_rdata(pkt, errs[le16toh(code)].err_msg, strlen(errs[le16toh(code)].err_msg) + 1);

	schedEvent(TASK_ROOT(task), txPkt, (void*) -1, TASK_FD(task), 
			TASK_DATA(task), RPACK_OFF(pkt));
	taskExit(task, NULL);
}

static void *
txAck(sched_task_t *task)
{
	rpack_t *pkt = TASK_DATA(task);
	u_short n = htons(TFTP_OPC_ACK);

	ETRACE();

	RPACK_REWIND(pkt);
	rpack_uint16(pkt, &n, 0);
	n = htons(cli.seq);
	rpack_uint16(pkt, &n, 0);

	schedEvent(TASK_ROOT(task), txPkt, NULL, TASK_FD(task), 
			TASK_DATA(task), RPACK_OFF(pkt));

	if (cli.close) {
		schedEvent(TASK_ROOT(task), execProg, "complete", 0, NULL, TFTP_OPC_WRQ);
		schedCancelby(TASK_ROOT(task), taskTIMER, CRITERIA_CALL, timeoutSession, NULL);
		schedEvent(TASK_ROOT(task), timeoutSession, NULL, 0, TASK_DATA(task), 0);
		EVERBOSE(2, "Finish WRQ request");
	}
	taskExit(task, NULL);
}

static int
getOpts(rpack_t * __restrict pkt, int rlen)
{
	char *opt, *val;
	int len;

	if (!rlen)
		return -1;

	do {
		/* option */
		len = str_getString(RPACK_NEXT(pkt), RPACK_REMAIN(pkt), NULL);
		if (len == -1)
			return -1;
		else
			rlen -= len;
		opt = (char*) rpack_rnext(pkt, len);
		if (!opt)
			return -1;
		EVERBOSE(7, "opt=%s rlen=%d", opt, rlen);
		/* value */
		len = str_getString(RPACK_NEXT(pkt), RPACK_REMAIN(pkt), NULL);
		if (len == -1)
			return -1;
		else
			rlen -= len;
		val = (char*) rpack_rnext(pkt, len);
		if (!val)
			return -1;
		EVERBOSE(7, "val=%s rlen=%d", val, rlen);

		if (!strcasecmp(opt, TFTP_OPT_BLKSIZE))
			cli.tmp = strtol(val, NULL, 10);
		else if (!strcasecmp(opt, TFTP_OPT_TSIZE))
			cli.tsiz = strtoll(val, NULL, 10);
		else if (!strcasecmp(opt, TFTP_OPT_TIMEOUT))
			cli.tout.tv_sec = strtol(val, NULL, 10);
		else if (!strcasecmp(opt, TFTP_OPT_ROLLOVER))
			cli.roll = strtol(val, NULL, 10);
	} while (rlen > 0);

	EVERBOSE(4, "blksize=%u tsize=%llu timeout=%u rollover=%u", 
			cli.siz, cli.tsiz, cli.tout.tv_sec, cli.roll);
	return 0;
}

static void *
txOack(sched_task_t *task)
{
	rpack_t *pkt = TASK_DATA(task);
	u_short n = htons(TFTP_OPC_OACK);
	struct stat sb;
	char szStr[STRSIZ];

	ETRACE();

	RPACK_REWIND(pkt);
	rpack_uint16(pkt, &n, 0);

	/* if opcode is RRQ and tsize is 0 then we must return file size to client */
	if (cli.opc == TFTP_OPC_RRQ && !cli.tsiz && stat(cli.file, &sb) != -1)
		cli.tsiz = sb.st_size;

	if (cli.siz > TFTP_LOAD_MAX) {
		memset(szStr, 0, sizeof szStr);
		snprintf(szStr, sizeof szStr, "%u", cli.siz);
		rpack_rdata(pkt, TFTP_OPT_BLKSIZE, strlen(TFTP_OPT_BLKSIZE) + 1);
		rpack_rdata(pkt, szStr, strlen(szStr) + 1);
	}
	if (cli.tsiz) {
		memset(szStr, 0, sizeof szStr);
		snprintf(szStr, sizeof szStr, "%llu", cli.tsiz);
		rpack_rdata(pkt, TFTP_OPT_TSIZE, strlen(TFTP_OPT_TSIZE) + 1);
		rpack_rdata(pkt, szStr, strlen(szStr) + 1);
	}
	if (cli.tout.tv_sec) {
		memset(szStr, 0, sizeof szStr);
		snprintf(szStr, sizeof szStr, "%u", cli.tout.tv_sec);
		rpack_rdata(pkt, TFTP_OPT_TIMEOUT, strlen(TFTP_OPT_TIMEOUT) + 1);
		rpack_rdata(pkt, szStr, strlen(szStr) + 1);
	}
	if (cli.roll) {
		memset(szStr, 0, sizeof szStr);
		snprintf(szStr, sizeof szStr, "%u", cli.roll);
		rpack_rdata(pkt, TFTP_OPT_ROLLOVER, strlen(TFTP_OPT_ROLLOVER) + 1);
		rpack_rdata(pkt, szStr, strlen(szStr) + 1);
	}

	EVERBOSE(4, "blksize=%u tsize=%llu timeout=%u rollover=%u", 
			cli.siz, cli.tsiz, cli.tout.tv_sec, cli.roll);
	schedEvent(TASK_ROOT(task), txPkt, NULL, TASK_FD(task), 
			TASK_DATA(task), RPACK_OFF(pkt));
	taskExit(task, NULL);
}

static void *
RQ(sched_task_t *task)
{
	rpack_t *pkt = TASK_DATA(task);
	struct tftp_hdr *tftp = (struct tftp_hdr*) RPACK_BUF(pkt);
	int len, rlen = TASK_DATLEN(task) - 2;
	char *str;
	u_short code = 0;

	ETRACE();

	cli.siz = TFTP_LOAD_MAX;
	cli.opc = ntohs(rpack_uint16(pkt, NULL, 0));
	len = str_getString(RPACK_NEXT(pkt), rlen, &str);
	if (len == -1)
		goto end;
	else {
		strlcpy(cli.file, (char*) RPACK_NEXT(pkt), sizeof cli.file);
		rlen -= len;
		rpack_rnext(pkt, len);
	}
	len = str_getString((const u_char*) str, rlen, NULL);
	if (len == -1)
		goto end;
	else {
		rlen -= len;
		rpack_rnext(pkt, len);
		if (!strcasecmp(str, TFTP_MODE_ASCII))
			strlcpy(cli.mode, TFTP_MODE_ASCII, sizeof cli.mode);
		else if (!strcasecmp(str, TFTP_MODE_OCTET))
			strlcpy(cli.mode, TFTP_MODE_OCTET, sizeof cli.mode);
		else if (!strcasecmp(str, TFTP_MODE_MAIL)) {
			strlcpy(cli.mode, TFTP_MODE_MAIL, sizeof cli.mode);
			code = htole16(4);
			goto end;
		} else {
			code = htole16(1);
			goto end;
		}
	}

	switch (cli.opc) {
		case TFTP_OPC_RRQ:
			code = O_RDONLY;
			EVERBOSE(2, "RRQ:: file=%s mode=%s\n", cli.file, cli.mode);
			break;
		case TFTP_OPC_WRQ:
			code = O_WRONLY | O_CREAT;
			str = (char*) cfg_getAttribute(&cfg, "tftpd", "override");
			if (!str || tolower(*str) != 'y')
				code |= O_EXCL;
			EVERBOSE(2, "WRQ:: file=%s mode=%s\n", cli.file, cli.mode);
			break;
	}

	cli.fd = open(cli.file, code, 0644);
	if (cli.fd == -1) {
		if (errno == EACCES)
			code = htole16(2);
		else if (errno == ENFILE)
			code = htole16(3);
		else if (errno == EEXIST)
			code = htole16(6);
		else
			code = htole16(0);
		ESYSERR(0);
		goto end;
	} else
		cli.seq = 0;

	schedEvent(TASK_ROOT(task), execProg, "request", 0, NULL, cli.opc);

	if (!getOpts(pkt, rlen)) {
		if (cli.tmp > TFTP_LOAD_MAX) {
			if (rpack_resize(pkt, cli.tmp + 4))
				ELIBERR(elwix);
			else
				cli.siz = cli.tmp;
		}
		if (cli.tout.tv_sec) {
			schedCancelby(TASK_ROOT(task), taskTIMER, CRITERIA_CALL, 
					timeoutSession, NULL);
			schedTimer(TASK_ROOT(task), timeoutSession, NULL, 
					cli.tout, TASK_DATA(task), 0);
		}
		schedEvent(TASK_ROOT(task), txOack, NULL, TASK_FD(task), 
				TASK_DATA(task), 0);
	} else if (cli.opc == TFTP_OPC_WRQ) {
		/* ack */
		tftp->tftp_opc = htons(TFTP_OPC_ACK);
		RPACK_REWIND(pkt);
		rpack_uint16(pkt, NULL, 0);
		rpack_uint16(pkt, &cli.seq, 0);

		schedEvent(TASK_ROOT(task), txPkt, NULL, TASK_FD(task), 
				TASK_DATA(task), RPACK_OFF(pkt));
	} else
		schedEvent(TASK_ROOT(task), txData, NULL, TASK_FD(task), 
				TASK_DATA(task), 0);

	cli.seq = 1;	/* 1st ack */
	taskExit(task, NULL);
end:
	tftp->tftp_opc = htons(TFTP_OPC_ERROR);
	RPACK_REWIND(pkt);
	rpack_uint16(pkt, NULL, 0);
	rpack_uint16(pkt, &code, 0);
	rpack_rdata(pkt, errs[le16toh(code)].err_msg, strlen(errs[le16toh(code)].err_msg) + 1);

	schedEvent(TASK_ROOT(task), txPkt, (void*) -1, TASK_FD(task), 
			TASK_DATA(task), RPACK_OFF(pkt));
	taskExit(task, NULL);
}

static void *
ACK(sched_task_t *task)
{
	rpack_t *pkt = TASK_DATA(task);
	struct tftp_hdr *tftp = (struct tftp_hdr*) RPACK_BUF(pkt);
	u_short code;

	ETRACE();

	RPACK_REWIND(pkt);
	code = rpack_uint16(pkt, NULL, 0);
	if (ntohs(code) != TFTP_OPC_ACK) {
		code = htole16(5);
		goto end;
	}

	code = rpack_uint16(pkt, NULL, 0);
	if (ntohs(code) > cli.seq || (ntohs(code) < (cli.seq - 1))) {
		code = htole16(5);
		goto end;
	} else if (ntohs(code) == cli.seq) {
		/* check for rollover seq id */
		if (cli.roll && cli.seq == USHRT_MAX)
			cli.seq = cli.roll;
		else
			cli.seq++;
	}

	EVERBOSE(3, "ACK:: seq=%hu; my new seq=%hu;", ntohs(code), cli.seq);

	if (!cli.close)
		schedEvent(TASK_ROOT(task), txData, NULL, TASK_FD(task), 
				TASK_DATA(task), 0);
	else {
		schedEvent(TASK_ROOT(task), execProg, "complete", 0, NULL, TFTP_OPC_RRQ);
		schedCancelby(TASK_ROOT(task), taskTIMER, CRITERIA_CALL, timeoutSession, NULL);
		schedEvent(TASK_ROOT(task), timeoutSession, NULL, 0, TASK_DATA(task), 0);
		EVERBOSE(2, "Finish RRQ request");
	}
	taskExit(task, NULL);
end:
	tftp->tftp_opc = htons(TFTP_OPC_ERROR);
	RPACK_REWIND(pkt);
	rpack_uint16(pkt, NULL, 0);
	rpack_uint16(pkt, &code, 0);
	rpack_rdata(pkt, errs[le16toh(code)].err_msg, strlen(errs[le16toh(code)].err_msg) + 1);

	schedEvent(TASK_ROOT(task), txPkt, (void*) -1, TASK_FD(task), 
			TASK_DATA(task), RPACK_OFF(pkt));
	taskExit(task, NULL);
}

static void *
DATA(sched_task_t *task)
{
	rpack_t *pkt = TASK_DATA(task);
	struct tftp_hdr *tftp = (struct tftp_hdr*) RPACK_BUF(pkt);
	u_short code;
	int len;

	ETRACE();

	RPACK_REWIND(pkt);
	code = rpack_uint16(pkt, NULL, 0);
	if (ntohs(code) != TFTP_OPC_DATA) {
		code = htole16(5);
		goto end;
	}

	code = rpack_uint16(pkt, NULL, 0);
	if (ntohs(code) < cli.seq || ntohs(code) > cli.seq + 1) {
		code = htole16(5);
		goto end;
	} else
		cli.seq = ntohs(code);

	/* max file size check */
	len = TASK_DATLEN(task) - RPACK_OFF(pkt);
	if (cli.tsiz && cli.tsiz < cli.seq * cli.siz)
		len = MIN(len, cli.tsiz - (cli.seq - 1) * cli.siz);
	if (len < cli.siz)
		cli.close = 42;	/* last received packet, should be close! */

	EVERBOSE(3, "DATA:: seq=%hu; len=%d", cli.seq, len);

	len = pwrite(cli.fd, RPACK_NEXT(pkt), len, (cli.seq - 1) * cli.siz);
	if (len == -1) {
		ESYSERR(0);
		code = htole16(3);
		goto end;
	} else {
		rpack_rnext(pkt, len);
		EVERBOSE(3, "Written to file %s %d bytes", cli.file, len);
	}

	schedEvent(TASK_ROOT(task), txAck, NULL, TASK_FD(task), TASK_DATA(task), 0);
	taskExit(task, NULL);
end:
	tftp->tftp_opc = htons(TFTP_OPC_ERROR);
	RPACK_REWIND(pkt);
	rpack_uint16(pkt, NULL, 0);
	rpack_uint16(pkt, &code, 0);
	rpack_rdata(pkt, errs[le16toh(code)].err_msg, strlen(errs[le16toh(code)].err_msg) + 1);

	schedEvent(TASK_ROOT(task), txPkt, (void*) -1, TASK_FD(task), 
			TASK_DATA(task), RPACK_OFF(pkt));
	taskExit(task, NULL);
}

void *
rxPkt(sched_task_t *task)
{
	sockaddr_t sa;
	socklen_t salen = sizeof sa;
	int rlen;
	rpack_t *pkt = TASK_DATA(task);
	struct tftp_hdr *tftp = (struct tftp_hdr*) RPACK_BUF(pkt);
	u_short code;

	ETRACE();

	memset(RPACK_BUF(pkt), 0, RPACK_LEN(pkt));
	rlen = recvfrom(TASK_FD(task), RPACK_BUF(pkt), RPACK_LEN(pkt), 0, &sa.sa, &salen);
	if (rlen == -1) {
		ESYSERR(0);
		goto end;
	} else if (!cli.addr.sa.sa_len) {
		cli.addr = sa;
		RPACK_REWIND(pkt);
		switch (ntohs(tftp->tftp_opc)) {
			case TFTP_OPC_RRQ:
			case TFTP_OPC_WRQ:
				schedEvent(TASK_ROOT(task), RQ, NULL, TASK_FD(task), 
						TASK_DATA(task), rlen);
				break;
			case TFTP_OPC_ERROR:
			default:
				RPACK_REWIND(pkt);
				code = htons(TFTP_OPC_ERROR);
				rpack_uint16(pkt, &code, 0);
				code = htole16(4);
				rpack_uint16(pkt, &code, 0);
				rpack_rdata(pkt, errs[4].err_msg, strlen(errs[4].err_msg) + 1);

				schedEvent(TASK_ROOT(task), txPkt, (void*) -1, TASK_FD(task), 
						TASK_DATA(task), RPACK_OFF(pkt));
				goto end;
		}
	} else if (memcmp(&cli.addr, &sa, salen)) {
		EERROR(LOG_WARNING, "Packet dropped!!!\n"
				"Get frame from different address for this session");
		goto end;
	} else
		switch (ntohs(tftp->tftp_opc)) {
			case TFTP_OPC_ACK:
				schedEvent(TASK_ROOT(task), ACK, NULL, TASK_FD(task), 
						TASK_DATA(task), rlen);
				break;
			case TFTP_OPC_DATA:
				schedEvent(TASK_ROOT(task), DATA, NULL, TASK_FD(task), 
						TASK_DATA(task), rlen);
				break;
			case TFTP_OPC_OACK:
			case TFTP_OPC_ERROR:
			default:
				RPACK_REWIND(pkt);
				code = htons(TFTP_OPC_ERROR);
				rpack_uint16(pkt, &code, 0);
				code = htole16(4);
				rpack_uint16(pkt, &code, 0);
				rpack_rdata(pkt, errs[4].err_msg, strlen(errs[4].err_msg) + 1);

				schedEvent(TASK_ROOT(task), txPkt, (void*) -1, TASK_FD(task), 
						TASK_DATA(task), RPACK_OFF(pkt));
				goto end;
		}

	schedCancelby(TASK_ROOT(task), taskTIMER, CRITERIA_CALL, timeoutSession, NULL);
	schedTimer(TASK_ROOT(task), timeoutSession, NULL, 
			cli.tout.tv_sec ? cli.tout : timeout, TASK_DATA(task), 0);
end:
	schedReadSelf(task);
	taskExit(task, NULL);
}