/*
 *   VUOS: view OS project
 *   Copyright (C) 2018  Renzo Davoli <renzo@cs.unibo.it>
 *   VirtualSquare team.
 *
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   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.  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, see <http://www.gnu.org/licenses/>.
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <libgen.h>
#include <getopt.h>
#include <string.h>
#include <errno.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stropt.h>
#include <strcase.h>
#include <vulib.h>

static char *progname;

/* This is the command that creates the list of proocol family names
	 echo "#include<sys/socket.h>" | gcc -E -dD - | egrep '^#define  *PF_.*[0-9]$' | \
	 awk 'BEGIN {printf "static char *pf_names[] = {\n"}   {printf "\t[%s] = \"%s\",\n", $3, substr(tolower($2),4)} END {printf "};\n"}'
 */

static char *pf_names[] = {
	[0] = "unspec",
	[1] = "local",
	[2] = "inet",
	[3] = "ax25",
	[4] = "ipx",
	[5] = "appletalk",
	[6] = "netrom",
	[7] = "bridge",
	[8] = "atmpvc",
	[9] = "x25",
	[10] = "inet6",
	[11] = "rose",
	[12] = "decnet",
	[13] = "netbeui",
	[14] = "security",
	[15] = "key",
	[16] = "netlink",
	[17] = "packet",
	[18] = "ash",
	[19] = "econet",
	[20] = "atmsvc",
	[21] = "rds",
	[22] = "sna",
	[23] = "irda",
	[24] = "pppox",
	[25] = "wanpipe",
	[26] = "llc",
	[27] = "ib",
	[28] = "mpls",
	[29] = "can",
	[30] = "tipc",
	[31] = "bluetooth",
	[32] = "iucv",
	[33] = "rxrpc",
	[34] = "isdn",
	[35] = "phonet",
	[36] = "ieee802154",
	[37] = "caif",
	[38] = "alg",
	[39] = "nfc",
	[40] = "vsock",
	[41] = "kcm",
	[42] = "qipcrtr",
	[43] = "smc",
	[44] = "xdp",
	[45] = "mctp",
	[46] = "max",
};

#define PF_NAMES_SIZE ((int)(sizeof(pf_names) / sizeof(*pf_names)))
#define PF_EXTRA_SIZE (PF_NAMES_SIZE + 10)

static unsigned char vustack_proto[PF_EXTRA_SIZE] = { [PF_UNSPEC] = 1 };

static char *pf_num2nname(int family) {
	if (family >= 0 && family < PF_NAMES_SIZE - 1)
		return pf_names[family];
	else
		return "unknown";
}

static int pf_name2num(char *pf_name) {
	int family;
	for (family = 0; family < PF_NAMES_SIZE; family++)
		if (pf_names[family] != NULL && strcmp(pf_name, pf_names[family]) == 0)
			return family;
	return -1;
}

static int is_a_stack(char *stack) {
	struct stat buf;
	int rv = stat(stack, &buf);
	if (rv < 0)
		return rv;
	else if ((buf.st_mode & S_IFMT) != S_IFSTACK)
		return errno=ENOTSUP, -1;
	else
		return 0;
}

static void add_supported_families(char *stack) {
	int family;
	vustack_proto[PF_UNSPEC] = 0;
	for (family = 1; family < PF_EXTRA_SIZE; family++) {
		int fd = msocket(stack, family, -1, 0);
		if (fd >= 0 || errno == EINVAL)
			vustack_proto[family] = 1;
		if (fd >= 0)
			close(fd);
	}
}

static void process_families(const char *input) {
	int tagc = stropt(input, NULL, NULL, 0);
	if(tagc > 0) {
		char buf[strlen(input)+1];
		char *tags[tagc];
		stropt(input, tags, NULL, buf);
		vustack_proto[PF_UNSPEC] = 0;
		for (int i=0; i < tagc - 1; i++) {
			switch(strcase_tolower(tags[i])) {
				case STRCASE(i,p):
					vustack_proto[PF_INET] = 1;
					vustack_proto[PF_INET6] = 1;
					vustack_proto[PF_NETLINK] = 1;
					vustack_proto[PF_PACKET] = 1;
					break;
				case STRCASE(i,p,v,4):
				case STRCASE(i,p,4):
					vustack_proto[PF_INET] = 1;
					break;
				case STRCASE(i,p,v,6):
				case STRCASE(i,p,6):
					vustack_proto[PF_INET6] = 1;
					break;
				case STRCASE(b,t):
					vustack_proto[PF_BLUETOOTH] = 1;
					break;
				case STRCASE(i,r):
					vustack_proto[PF_IRDA] = 1;
					break;
				default:
					if (isdigit(tags[i][0])) {
						int family = strtol(tags[i], NULL, 0);
						if (family > 0 && family < PF_EXTRA_SIZE)
							vustack_proto[family] = 1;
						else {
							fprintf(stderr, "%s: unknown protocol family %s\n", progname, tags[i]);
							exit(1);
						}
					} else {
						int family = pf_name2num(tags[i]);
						if (family > 0)
							vustack_proto[family] = 1;
						else {
							fprintf(stderr, "%s: unknown protocol family %s\n", progname, tags[i]);
							exit(1);
						}
					}
			}
		}
	}
}

static char *short_options = "hvsf:";
static struct option long_options[] = {
	{"help", no_argument, 0, 'h'},
	{"verbose", no_argument, 0, 'v'},
	{"supported", no_argument, 0, 's'},
	{"family", required_argument, 0, 'f'},
	{"families", required_argument, 0, 'f'},
	{0, 0, 0, 0}
};

void usage(char *progname, int verbose)
{
	fprintf(stderr,
			"%s: set the default networking stack\n\n"
			"Usage: %s [options] stack cmd [args]\n\n"
			"    -h --help            print this short usage message\n"
			"    -f list\n"
			"      -family list\n"
			"      -families list     set the list of address families\n"
			"    -s --supported       all families supported by the stack\n\n"
			"    -v --verbose         verbose mode\n\n",
			progname, progname);

	if (verbose) {
		int family;
		fprintf(stderr, "List address family names and numbers:\n");
		for (family = 1; family < PF_NAMES_SIZE; family++)
			if (pf_names[family] != NULL)
				fprintf(stderr, "%5d: %s\n", family, pf_names[family]);
		fprintf(stderr, "\nMax family number %d\n", PF_EXTRA_SIZE - 1);
		fprintf(stderr, "\nAliases:\n"
				"  ip: inet,inet6,netlink,packet\n"
				"  ipv4: inet, ip4: inet, ipv6: inet6, ip6: inet6, bt: bluetooth, ir: irda\n\n");
	}
	exit(1);
}

int main(int argc, char *argv[])
{
	int c;
	int verbose = 0;
	int supported = 0;
	progname = basename(argv[0]);

	if (vu_getinfo(NULL) < 0) {
		fprintf(stderr, "%s is a vuos command\n", progname);
		return 1;
	}

	while (1) {
		int option_index = 0;
		c = getopt_long(argc, argv, short_options,
				long_options, &option_index);
		if (c == -1)
			break;
		switch (c) {
			case 'f':
				process_families(optarg);
				break;
			case 'v':
				verbose = 1;
				break;
			case 's':
				supported = 1;
				break;
			case 'h':
			default:
				usage(argv[0], verbose);
				break;
		}
	}

	if (argc > optind + 1) {
		char *stack = argv[optind];
		char *cmd = argv[optind + 1];
		char **newargv = argv + (optind + 1);

		if (is_a_stack(stack) < 0) {
			perror(stack);
			exit(1);
		}

		if (supported)
			add_supported_families(stack);

		if (vustack_proto[PF_UNSPEC] == 1) {
			if (verbose)
				fprintf(stderr, "Using %s for ALL address families\n", stack);
			if (msocket(stack, 0, SOCK_DEFAULT, 0) < 0) {
				perror("vustack: msocket");
				exit(1);
			}
		} else {
			int family;
			if (verbose) {
				fprintf(stderr, "Using %s for the following address families:\n   ", stack);
				for(family = 1; family < PF_EXTRA_SIZE; family++) {
					if (vustack_proto[family] == 1) {
						fprintf(stderr," %s(%d)", pf_num2nname(family), family);
					}
				}
				fprintf(stderr,"\n");
			}
			for(family = 1; family < PF_EXTRA_SIZE; family++) {
				if (vustack_proto[family] == 1) {
					if (msocket(stack, family, SOCK_DEFAULT, 0) < 0) {
						perror("vustack: msocket");
						exit(1);
					}
				}
			}
		}

		execvp(cmd, newargv);
	} else
		usage(progname, verbose);
	return 1;
}