/*

Copyright (c) 2004 Carl Byington - 510 Software Group, released under
the GPL version 2 or any later version at your choice available at
http://www.fsf.org/licenses/gpl.txt

*/

#include "includes.h"

static char* context_version="$Id$";

char *token_black;
char *token_content;
char *token_context;
char *token_dccfrom;
char *token_dccto;
char *token_default;
char *token_dnsbl;
char *token_dnsbll;
char *token_envfrom;
char *token_envto;
char *token_filter;
char *token_host_limit;
char *token_html_limit;
char *token_html_tags;
char *token_ignore;
char *token_include;
char *token_inherit;
char *token_lbrace;
char *token_mailhost;
char *token_many;
char *token_off;
char *token_ok2;
char *token_ok;
char *token_on;
char *token_rbrace;
char *token_semi;
char *token_soft;
char *token_substitute;
char *token_tld;
char *token_unknown;
char *token_white;

string_set all_strings; 	// owns all the strings, only modified by the config loader thread
const int maxlen = 1000;

DNSBL::DNSBL(char *n, char *s, char *m) {
	name	= n;
	suffix	= s;
	message = m;
}


bool DNSBL::operator==(const DNSBL &rhs) {
	return (strcmp(name,	rhs.name)	 == 0) &&
		   (strcmp(suffix,	rhs.suffix)  == 0) &&
		   (strcmp(message, rhs.message) == 0);
}


CONFIG::CONFIG() {
	reference_count    = 0;
	generation		   = 0;
	load_time		   = 0;
	default_context    = NULL;
}


CONFIG::~CONFIG() {
	for (context_list::iterator i=contexts.begin(); i!=contexts.end(); i++) {
		CONTEXT *c = *i;
		delete c;
	}
}


void CONFIG::add_context(CONTEXTP con) {
	contexts.push_back(con);
	if (!default_context && !con->get_parent()) {
		// first global context
		default_context = con;
	}
}


void CONFIG::add_to(char *to, CONTEXTP con) {
	context_map::iterator i = env_to.find(to);
	if (i != env_to.end()) {
		CONTEXTP  c = (*i).second;
		int 	  s = strlen(to);
		bool	 at = s && (to[s-1] == '@');
		if (at && con->is_parent(c->get_parent())) {
			if (debug_syslog) {
				char oldname[maxlen];
				char newname[maxlen];
				char *oldn = c->get_full_name(oldname, maxlen);
				char *newn = con->get_full_name(newname, maxlen);
				char buf[maxlen*3];
				snprintf(buf, maxlen*3, "both %s and %s claim envelope to %s, the first one wins", oldn, newn, to);
				my_syslog(buf);
			}
			return; 	// don't take over user@ entries from your ancestors children
		}
		if ((c != con) && (c != con->get_parent())) {
			if (debug_syslog) {
				char oldname[maxlen];
				char newname[maxlen];
				char *oldn = c->get_full_name(oldname, maxlen);
				char *newn = con->get_full_name(newname, maxlen);
				char buf[maxlen*3];
				snprintf(buf, maxlen*3, "both %s and %s claim envelope to %s, the second one wins", oldn, newn, to);
				my_syslog(buf);
			}
		}
	}
	env_to[to] = con;
}


CONTEXTP CONFIG::find_context(char *to) {
	context_map::iterator i = env_to.find(to);
	if (i != env_to.end()) return (*i).second;		// found user@domain.tld key
	char *x = strchr(to, '@');
	if (x) {
		x++;
		i = env_to.find(x);
		if (i != env_to.end()) return (*i).second;	// found domain.tld key
		char y = *x;
		*x = '\0';
		i = env_to.find(to);
		*x = y;
		if (i != env_to.end()) return (*i).second;	// found user@ key
	}
	return default_context;
}


void CONFIG::dump() {
	if (default_context) default_context->dump();
	for (context_list::iterator i=contexts.begin(); i!=contexts.end(); i++) {
		CONTEXTP c = *i;
		CONTEXTP p = c->get_parent();
		if (!p && (c != default_context)) c->dump();
	}
	char buf[maxlen];
	for (context_map::iterator i=env_to.begin(); i!=env_to.end(); i++) {
		char	 *to = (*i).first;
		CONTEXTP con = (*i).second;
		printf("// envelope to %s \t-> context %s \n", to, con->get_full_name(buf,maxlen));
	}
}


CONTEXT::CONTEXT(CONTEXTP parent_, char *name_) {
	parent				= parent_;
	name				= name_;
	env_from_default	= (parent) ? token_inherit : token_unknown;
	content_filtering	= (parent) ? parent->content_filtering : false;
	content_suffix		= NULL;
	content_message 	= NULL;
	host_limit			= (parent) ? parent->host_limit  : 0;
	host_limit_message	= NULL;
	host_random 		= (parent) ? parent->host_random : false;
	tag_limit			= (parent) ? parent->tag_limit	 : 0;
	tag_limit_message	= NULL;
}


CONTEXT::~CONTEXT() {
	for (dnsblp_map::iterator i=dnsbl_names.begin(); i!=dnsbl_names.end(); i++) {
		DNSBLP d = (*i).second;
		// delete the underlying DNSBL objects.
		delete d;
	}
}


bool CONTEXT::is_parent(CONTEXTP p) {
	if (p == parent) return true;
	if (!parent) return false;
	return parent->is_parent(p);
}


char *CONTEXT::get_full_name(char *buffer, int size) {
	if (!parent) return name;
	char buf[maxlen];
	snprintf(buffer, size, "%s.%s", parent->get_full_name(buf, maxlen), name);
	return buffer;
}


bool CONTEXT::cover_env_to(char *to) {
	char buffer[maxlen];
	char *x = strchr(to, '@');
	if (x) x++;
	else   x = to;
	if (*x == '\0') return true;    // always allow covering addresses with no domain name, eg abuse@
	string_set::iterator i = env_to.find(x);
	if (i != env_to.end()) return true;
	return false;
}


char *CONTEXT::find_from(char *from) {
	char *rc = token_inherit;
	string_map::iterator i = env_from.find(from);
	if (i != env_from.end()) rc = (*i).second;	// found user@domain.tld key
	else {
		char *x = strchr(from, '@');
		if (x) {
			x++;
			i = env_from.find(x);
			if (i != env_from.end()) rc = (*i).second;	// found domain.tld key
			else {
				char y = *x;
				*x = '\0';
				i = env_from.find(from);
				*x = y;
				if (i != env_from.end()) rc = (*i).second;	// found user@ key
			}
		}
	}
	if (rc == token_inherit) rc = env_from_default;
	if ((rc == token_inherit) && parent) return parent->find_from(from);
	return (rc == token_inherit) ? token_unknown : rc;
}


CONTEXTP CONTEXT::find_context(char *from) {
	context_map::iterator i = env_from_context.find(from);
	if (i != env_from_context.end()) return (*i).second;		// found user@domain.tld key
	char *x = strchr(from, '@');
	if (x) {
		x++;
		i = env_from_context.find(x);
		if (i != env_from_context.end()) return (*i).second;	// found domain.tld key
		char y = *x;
		*x = '\0';
		i = env_from_context.find(from);
		*x = y;
		if (i != env_from_context.end()) return (*i).second;			  // found user@ key
	}
	return this;
}


CONTEXTP CONTEXT::find_from_context_name(char *name) {
	context_map::iterator i = children.find(name);
	if (i != children.end()) return (*i).second;
	return NULL;
}


DNSBLP CONTEXT::find_dnsbl(char *name) {
	dnsblp_map::iterator i = dnsbl_names.find(name);
	if (i != dnsbl_names.end()) return (*i).second;
	if (parent) return parent->find_dnsbl(name);
	return NULL;
}


char* CONTEXT::get_content_suffix() {
	if (!content_suffix && parent) return parent->get_content_suffix();
	return content_suffix;
}


char* CONTEXT::get_content_message() {
	if (!content_message && parent) return parent->get_content_message();
	return content_message;
}


string_set& CONTEXT::get_content_host_ignore() {
	if (content_host_ignore.empty() && parent) return parent->get_content_host_ignore();
	return content_host_ignore;
}


string_set& CONTEXT::get_content_tlds() {
	if (content_tlds.empty() && parent) return parent->get_content_tlds();
	return content_tlds;
}


string_set& CONTEXT::get_html_tags() {
	if (html_tags.empty() && parent) return parent->get_html_tags();
	return html_tags;
}


dnsblp_list& CONTEXT::get_dnsbl_list() {
	if (dnsbl_list.empty() && parent) return parent->get_dnsbl_list();
	return dnsbl_list;
}


bool CONTEXT::acceptable_content(recorder &memory, char *&msg) {
	if (memory.excessive_bad_tags(tag_limit)) {
		msg = tag_limit_message;
		return false;
	}
	if (!host_random && memory.excessive_hosts(host_limit)) {
		msg = host_limit_message;
		return false;
	}
	return true;
}


void CONTEXT::dump(int level) {
	char indent[maxlen];
	int i = min(maxlen-1, level*4);
	memset(indent, ' ', i);
	indent[i] = '\0';
	char buf[maxlen];
	char *fullname = get_full_name(buf,maxlen);
	printf("%s context %s { \t// %s\n", indent, name, fullname);

	for (dnsblp_map::iterator i=dnsbl_names.begin(); i!=dnsbl_names.end(); i++) {
		char *n = (*i).first;
		DNSBL &d = *(*i).second;
		printf("%s     dnsbl %s %s \"%s\"; \n", indent, n, d.suffix, d.message);
	}

	if (!dnsbl_list.empty()) {
		printf("%s     dnsbl_list", indent);
		for (dnsblp_list::iterator i=dnsbl_list.begin(); i!=dnsbl_list.end(); i++) {
			DNSBL &d = *(*i);
			printf(" %s", d.name);
		}
		printf("; \n");
	}

	if (content_filtering) {
		printf("%s     content on { \n", indent, env_from_default);
		if (content_suffix) {
			printf("%s         filter %s \"%s\"; \n", indent, content_suffix, content_message);
		}
		if (!content_host_ignore.empty()) {
			printf("%s         ignore { \n", indent);
			for (string_set::iterator i=content_host_ignore.begin(); i!=content_host_ignore.end(); i++) {
				printf("%s             %s; \n", indent, *i);
			}
			printf("%s         }; \n", indent);
		}
		if (!content_tlds.empty()) {
			printf("%s         tld { \n", indent);
			printf("%s             ", indent);
			for (string_set::iterator i=content_tlds.begin(); i!=content_tlds.end(); i++) {
				printf("%s; ", *i);
			}
			printf("\n%s         }; \n", indent);
		}
		if (!html_tags.empty()) {
			printf("%s         html_tags { \n", indent);
			printf("%s             ", indent);
			for (string_set::iterator i=html_tags.begin(); i!=html_tags.end(); i++) {
				printf("%s; ", *i);
			}
			printf("\n%s         }; \n", indent);
		}
		if (host_limit_message) {
			printf("%s         host_limit on %d \"%s\"; \n", indent, host_limit, host_limit_message);
		}
		else if (host_random) {
			printf("%s         host_limit soft %d; \n", indent, host_limit);
		}
		else {
			printf("%s         host_limit off; \n", indent);
		}
		if (tag_limit_message) {
			printf("%s         html_limit on %d \"%s\"; \n", indent, tag_limit, tag_limit_message);
		}
		else {
			printf("%s         html_limit off; \n", indent);
		}
		printf("%s     }; \n", indent);
		}
	else {
		printf("%s     content off {}; \n", indent, env_from_default);
	}

	printf("%s     env_to { \t// %s\n", indent, fullname);
	for (string_set::iterator i=env_to.begin(); i!=env_to.end(); i++) {
		printf("%s         %s; \n", indent, *i);
	}
	printf("%s     }; \n", indent);

	for (context_map::iterator i=children.begin(); i!=children.end(); i++) {
		CONTEXTP c = (*i).second;
		c->dump(level+1);
	}

	printf("%s     env_from %s { \t// %s\n", indent, env_from_default, fullname);
	if (!env_from.empty()) {
		printf("%s     // white/black/unknown \n", indent);
		for (string_map::iterator i=env_from.begin(); i!=env_from.end(); i++) {
			char *f = (*i).first;
			char *t = (*i).second;
			printf("%s         %s \t%s; \n", indent, f, t);
		}
	}
	if (!env_from_context.empty()) {
		printf("%s     // child contexts \n", indent);
		for (context_map::iterator j=env_from_context.begin(); j!=env_from_context.end(); j++) {
			char	*f = (*j).first;
			CONTEXTP t = (*j).second;
			printf("%s         %s \t%s; \n", indent, f, t->name);
		}
	}
	printf("%s     }; \n", indent);

	printf("%s }; \n", indent);
}


////////////////////////////////////////////////
// helper to discard the strings held by a string_set
//
void discard(string_set &s) {
	for (string_set::iterator i=s.begin(); i!=s.end(); i++) {
		free(*i);
	}
	s.clear();
}


////////////////////////////////////////////////
// helper to register a string in a string set
//
char* register_string(string_set &s, char *name) {
	string_set::iterator i = s.find(name);
	if (i != s.end()) return *i;
	char *x = strdup(name);
	s.insert(x);
	return x;
}


////////////////////////////////////////////////
// register a global string
//
char* register_string(char *name) {
	return register_string(all_strings, name);
}


////////////////////////////////////////////////
//
bool tsa(TOKEN &tok, char *token);
bool tsa(TOKEN &tok, char *token) {
	char *have = tok.next();
	if (have == token) return true;
	tok.token_error(token, have);
	return false;
}


////////////////////////////////////////////////
//
bool parse_dnsbl(TOKEN &tok, CONFIG &dc, CONTEXT &me);
bool parse_dnsbl(TOKEN &tok, CONFIG &dc, CONTEXT &me) {
	char *name = tok.next();
	char *suf = tok.next();
	char *msg = tok.next();
	if (!tsa(tok, token_semi)) return false;
	DNSBLP dnsnew = new DNSBL(name, suf, msg);
	DNSBLP dnsold = me.find_dnsbl(name);
	if (dnsold && (*dnsold == *dnsnew)) {
		// duplicate redefinition, ignore it
		delete dnsnew;
		return true;
	}
	me.add_dnsbl(name, dnsnew);
	return true;
}


////////////////////////////////////////////////
//
bool parse_dnsbll(TOKEN &tok, CONFIG &dc, CONTEXT &me);
bool parse_dnsbll(TOKEN &tok, CONFIG &dc, CONTEXT &me) {
	while (true) {
		char *have = tok.next();
		if (!have) break;
		if (have == token_semi) break;
		DNSBLP dns = me.find_dnsbl(have);
		if (dns) {
			me.add_dnsbl(dns);
		}
		else {
			tok.token_error("dnsbl name", have);
			return false;
		}
	}
	return true;
}


////////////////////////////////////////////////
//
bool parse_content(TOKEN &tok, CONFIG &dc, CONTEXT &me);
bool parse_content(TOKEN &tok, CONFIG &dc, CONTEXT &me) {
	char *setting = tok.next();
	if (setting == token_on) {
		me.set_content_filtering(true);
	}
	else if (setting == token_off) {
		me.set_content_filtering(false);
	}
	else {
		tok.token_error("on/off", setting);
		return false;
	}
	if (!tsa(tok, token_lbrace)) return false;
	while (true) {
		char *have = tok.next();
		if (!have) break;
		if (have == token_filter) {
			char *suffix = tok.next();
			char *messag = tok.next();
			me.set_content_suffix(suffix);
			me.set_content_message(messag);
			if (!tsa(tok, token_semi)) return false;
		}
		else if (have == token_ignore) {
			if (!tsa(tok, token_lbrace)) return false;
			while (true) {
				if (!have) break;
				char *have = tok.next();
				if (have == token_rbrace) break;  // done
				me.add_ignore(have);
			}
			if (!tsa(tok, token_semi)) return false;
		}
		else if (have == token_tld) {
			if (!tsa(tok, token_lbrace)) return false;
			while (true) {
				char *have = tok.next();
				if (!have) break;
				if (have == token_rbrace) break;  // done
				me.add_tld(have);
			}
			if (!tsa(tok, token_semi)) return false;
		}
		else if (have == token_html_limit) {
			have = tok.next();
			if (have == token_on) {
				me.set_tag_limit(tok.nextint());
				me.set_tag_message(tok.next());
			}
			else if (have == token_off) {
				me.set_tag_limit(0);
				me.set_tag_message(NULL);
			}
			else {
				tok.token_error("on/off", have);
				return false;
			}
			if (!tsa(tok, token_semi)) return false;
		}
		else if (have == token_html_tags) {
			if (!tsa(tok, token_lbrace)) return false;
			while (true) {
				char *have = tok.next();
				if (!have) break;
				if (have == token_rbrace) {
					break;	// done
				}
				else {
					me.add_tag(have);							// base version
					char buf[200];
					snprintf(buf, sizeof(buf), "/%s", have);
					me.add_tag(register_string(buf));			// leading /
					snprintf(buf, sizeof(buf), "%s/", have);
					me.add_tag(register_string(buf));			// trailing /
				}
			}
			if (!tsa(tok, token_semi)) return false;
		}
		else if (have == token_host_limit) {
			have = tok.next();
			if (have == token_on) {
				me.set_host_limit(tok.nextint());
				me.set_host_message(tok.next());
				me.set_host_random(false);
			}
			else if (have == token_off) {
				me.set_host_limit(0);
				me.set_host_message(NULL);
				me.set_host_random(false);
			}
			else if (have == token_soft) {
				me.set_host_limit(tok.nextint());
				me.set_host_message(NULL);
				me.set_host_random(true);
			}
			else {
				tok.token_error("on/off/soft", have);
				return false;
			}
			if (!tsa(tok, token_semi)) return false;
		}
		else if (have == token_rbrace) {
			break;	// done
		}
		else {
			tok.token_error("content keyword", have);
			return false;
		}
	}
	return tsa(tok, token_semi);
}


////////////////////////////////////////////////
//
bool parse_envto(TOKEN &tok, CONFIG &dc, CONTEXT &me);
bool parse_envto(TOKEN &tok, CONFIG &dc, CONTEXT &me) {
	if (!tsa(tok, token_lbrace)) return false;
	while (true) {
		char *have = tok.next();
		if (!have) break;
		if (have == token_rbrace) break;
		if (have == token_semi) {
			// optional separators
		}
		else if (have == token_dccto) {
			char *flavor = tok.next();
			if (!tsa(tok, token_lbrace)) return false;
			bool keeping = false;
			while (true) {
				char *have = tok.next();
				if (!have) break;
				if (have == token_rbrace) break;
				if (have == flavor) {
					keeping = true;
					continue;
				}
				else if ((have == token_ok) || (have == token_ok2) || (have == token_many)) {
					keeping = false;
					continue;
				}
				if (have == token_envto) {
					have = tok.next();
					if (keeping) {
						if (me.allow_env_to(have)) {
							me.add_to(have);
							dc.add_to(have, &me);
						}
					}
				}
				else if (have == token_substitute) {
					if (tok.next() == token_mailhost) {
						have = tok.next();
						if (keeping) {
							if (me.allow_env_to(have)) {
								me.add_to(have);
								dc.add_to(have, &me);
							}
						}
					}
				}
				tok.skipeol();
			}
		}
		else if (me.allow_env_to(have)) {
			me.add_to(have);
			dc.add_to(have, &me);
		}
		else {
			tok.token_error("user@ or user@domain.tld or domain.tld where domain.tld allowed by parent context", have);
			return false;
		}
	}
	return tsa(tok, token_semi);
}


////////////////////////////////////////////////
//
bool parse_envfrom(TOKEN &tok, CONFIG &dc, CONTEXT &me);
bool parse_envfrom(TOKEN &tok, CONFIG &dc, CONTEXT &me) {
	char *st = tok.next();
	if ((st == token_black) || (st == token_white) || (st == token_unknown) || (st == token_inherit)) {
		me.set_from_default(st);
	}
	else {
		tok.push(st);
	}
	if (!tsa(tok, token_lbrace)) return false;
	while (true) {
		char *have = tok.next();
		if (!have) break;
		if (have == token_rbrace) break;
		if (have == token_semi) {
			// optional separators
		}
		else if (have == token_dccfrom) {
			if (!tsa(tok, token_lbrace)) return false;
			bool keeping = false;
			bool many = false;
			while (true) {
				char *have = tok.next();
				if (!have) break;
				if (have == token_rbrace) break;
				if (have == token_ok) {
					keeping = true;
					many	= false;
					continue;
				}
				else if (have == token_many) {
					keeping = true;
					many	= true;
					continue;
				}
				else if (have == token_ok2) {
					keeping = false;
					continue;
				}
				if (have == token_envfrom) {
					have = tok.next();
					if (keeping) {
						me.add_from(have, (many) ? token_black : token_white);
					}
				}
				else if (have == token_substitute) {
					if (tok.next() == token_mailhost) {
						have = tok.next();
						me.add_from(have, (many) ? token_black : token_white);
					}
				}
				tok.skipeol();
			}
		}
		else {
			// may be a valid email address or domain name
			char *st = tok.next();
			if ((st == token_black) || (st == token_white) || (st == token_unknown)) {
				me.add_from(have, st);
			}
			else {
				CONTEXTP con = me.find_from_context_name(st);
				if (con) {
					me.add_from_context(have, con);
				}
				else {
					tok.token_error("white/black/unknown or child context name", st);
					return false;
				}
			}
		}
	}
	return tsa(tok, token_semi);
}


////////////////////////////////////////////////
//
bool parse_context(TOKEN &tok, CONFIG &dc, CONTEXTP parent);
bool parse_context(TOKEN &tok, CONFIG &dc, CONTEXTP parent) {
	char *name = tok.next();
	if (!tsa(tok, token_lbrace)) return false;
	CONTEXTP con = new CONTEXT(parent, name);

	while (true) {
		char *have = tok.next();
		if (!have) break;
		if (have == token_rbrace) break;  // done
		if (have == token_dnsbl) {
			if (!parse_dnsbl(tok, dc, *con)) return false;
		}
		else if (have == token_dnsbll) {
			if (!parse_dnsbll(tok, dc, *con)) return false;
		}
		else if (have == token_content) {
			if (!parse_content(tok, dc, *con)) return false;
		}
		else if (have == token_envto) {
			if (!parse_envto(tok, dc, *con)) return false;
		}
		else if (have == token_envfrom) {
			if (!parse_envfrom(tok, dc, *con)) return false;
		}
		else if (have == token_context) {
			if (!parse_context(tok, dc, con)) return false;
		}
		else {
			tok.token_error("context keyword", have);
			return false;
		}
	}

	if (!tsa(tok, token_semi)) {
		delete con;
		return false;
	}
	dc.add_context(con);
	if (parent) parent->add_context(con);
	return true;
}


////////////////////////////////////////////////
// parse a config file
//
bool load_conf(CONFIG &dc, char *fn) {
	TOKEN tok(fn, &dc.config_files);
	while (true) {
		char *have = tok.next();
		if (!have) break;
		if (have == token_context) {
			if (!parse_context(tok, dc, NULL)) {
				return false;
			}
		}
		else {
			tok.token_error(token_context, have);
			return false;
		}
	}
	return (dc.default_context) ? true : false;
}


////////////////////////////////////////////////
// init the tokens
//
void token_init() {
	token_black 	 = register_string("black");
	token_content	 = register_string("content");
	token_context	 = register_string("context");
	token_dccfrom	 = register_string("dcc_from");
	token_dccto 	 = register_string("dcc_to");
	token_default	 = register_string("default");
	token_dnsbl 	 = register_string("dnsbl");
	token_dnsbll	 = register_string("dnsbl_list");
	token_envfrom	 = register_string("env_from");
	token_envto 	 = register_string("env_to");
	token_filter	 = register_string("filter");
	token_host_limit = register_string("host_limit");
	token_html_limit = register_string("html_limit");
	token_html_tags  = register_string("html_tags");
	token_ignore	 = register_string("ignore");
	token_include	 = register_string("include");
	token_inherit	 = register_string("inherit");
	token_lbrace	 = register_string("{");
	token_mailhost	 = register_string("mail_host");
	token_many		 = register_string("many");
	token_off		 = register_string("off");
	token_ok		 = register_string("ok");
	token_ok2		 = register_string("ok2");
	token_on		 = register_string("on");
	token_rbrace	 = register_string("}");
	token_semi		 = register_string(";");
	token_soft		 = register_string("soft");
	token_substitute = register_string("substitute");
	token_tld		 = register_string("tld");
	token_unknown	 = register_string("unknown");
	token_white 	 = register_string("white");
}