/*
 * Copyright (c) 2020-2024 Omar Polo <op@omarpolo.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#ifndef GMID_H
#define GMID_H

#include "config.h"

#include <sys/socket.h>
#include <sys/types.h>

#include <arpa/inet.h>
#include <netinet/in.h>

#include <dirent.h>
#include <limits.h>
#include <netdb.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <tls.h>
#include <unistd.h>

#include <openssl/x509.h>

#if HAVE_EVENT2
# include <event2/event.h>
# include <event2/event_compat.h>
# include <event2/event_struct.h>
# include <event2/buffer.h>
# include <event2/buffer_compat.h>
# include <event2/bufferevent.h>
# include <event2/bufferevent_struct.h>
# include <event2/bufferevent_compat.h>
#else
# include <event.h>
#endif

#include "iri.h"

#define VERSION_STR(n)	n " " VERSION
#define GEMEXP_STRING	VERSION_STR("gemexp")
#define GG_STRING	VERSION_STR("gg")
#define GMID_STRING	VERSION_STR("gmid")

#define GMID_VERSION	"gmid/" VERSION

#define GEMINI_URL_LEN (1024+3)	/* URL max len + \r\n + \0 */

#define SUCCESS		20
#define TEMP_REDIRECT	30
#define TEMP_FAILURE	40
#define CGI_ERROR	42
#define PROXY_ERROR	43
#define NOT_FOUND	51
#define PROXY_REFUSED	53
#define BAD_REQUEST	59
#define CLIENT_CERT_REQ	60
#define CERT_NOT_AUTH	61

/* maximum hostname and label length, +1 for the NUL-terminator */
#define DOMAIN_NAME_LEN	(253+1)
#define LABEL_LEN	(63+1)

#define MEDIATYPE_NAMEMAX	128	/* file name extension */
#define MEDIATYPE_TYPEMAX	128	/* length of type/subtype */

#define FCGI_NAME_MAX		511
#define FCGI_VAL_MAX		511

#define PROC_MAX_INSTANCES	16

#define TLS_CERT_HASH_SIZE	128

/*
 * glibc is violating POSIX by defining HOST_NAME_MAX to a ridicully
 * small value, so we can't use it.  Luckily, we don't have to do DNS
 * so we don't risk to pass buffers too big to functions that might
 * not expect them, we just need a fixed size buffer to catch possible
 * misconfigurations.
 */
#define GMID_HOST_NAME_MAX	255	/* without NUL */

/* forward declaration */
struct privsep;
struct privsep_proc;

enum log_format {
	LOG_FORMAT_CONDENSED,
	LOG_FORMAT_COMMON,
	LOG_FORMAT_COMBINED,
	LOG_FORMAT_LEGACY,
};

struct parser {
	char		*iri;
	struct iri	*parsed;
	const char	*err;
};

struct conf;
TAILQ_HEAD(addrhead, address);
struct address {
	int			 ai_flags;
	int			 ai_family;
	int			 ai_socktype;
	int			 ai_protocol;
	struct sockaddr_storage	 ss;
	socklen_t		 slen;
	int16_t			 port;
	int			 proxy;

	/* pretty-printed version of `ss' */
	char			 pp[NI_MAXHOST];

	/* used in the server */
	struct conf		*conf;
	int			 sock;
	struct event		 evsock; /* set if sock != -1 */
	struct tls		*ctx;

	TAILQ_ENTRY(address)	 addrs;
};

TAILQ_HEAD(fcgihead, fcgi);
struct fcgi {
	int		 id;
	char		 path[PATH_MAX];
	char		 port[32];
	TAILQ_ENTRY(fcgi) fcgi;
};

TAILQ_HEAD(envhead, envlist);
struct envlist {
	char		 name[FCGI_NAME_MAX];
	char		 value[FCGI_VAL_MAX];
	TAILQ_ENTRY(envlist) envs;
};

TAILQ_HEAD(aliashead, alist);
struct alist {
	char		alias[GMID_HOST_NAME_MAX + 1];
	TAILQ_ENTRY(alist) aliases;
};

TAILQ_HEAD(proxyhead, proxy);
struct proxy {
	char		 match_proto[32];
	char		 match_host[GMID_HOST_NAME_MAX + 1];
	char		 match_port[32];

	char		 host[GMID_HOST_NAME_MAX + 1];
	char		 port[32];
	char		 sni[GMID_HOST_NAME_MAX];
	int		 notls;
	uint32_t	 protocols;
	int		 noverifyname;
	char		*cert_path;
	uint8_t		*cert;
	size_t		 certlen;
	char		*key_path;
	uint8_t		*key;
	size_t		 keylen;
	char		*reqca_path;
	X509_STORE	*reqca;
	int		 proxy;	/* use the proxy protocol */

	TAILQ_ENTRY(proxy) proxies;
};

TAILQ_HEAD(lochead, location);
struct location {
	char		 match[128];
	char		 lang[32];
	char		 default_mime[MEDIATYPE_TYPEMAX];
	char		 index[PATH_MAX];
	int		 auto_index; /* 0 auto, -1 off, 1 on */
	int		 block_code;
	char		 block_fmt[GEMINI_URL_LEN];
	int		 strip;
	char		*reqca_path;
	X509_STORE	*reqca;
	int		 disable_log;
	int		 fcgi;
	int		 nofcgi;
	int		 fcgi_strip;
	struct envhead	 params;

	char		 dir[PATH_MAX];
	int		 dirfd;

	TAILQ_ENTRY(location) locations;
};

TAILQ_HEAD(vhosthead, vhost);
struct vhost {
	char		 domain[GMID_HOST_NAME_MAX + 1];
	char		*cert_path;
	char		*key_path;
	char		*ocsp_path;

	uint8_t		*cert;
	size_t		 certlen;

	uint8_t		*key;
	size_t		 keylen;

	uint8_t		*ocsp;
	size_t		 ocsplen;

	TAILQ_ENTRY(vhost) vhosts;

	struct addrhead	 addrs;

	/*
	 * the first location rule is always '*' and holds the default
	 * settings for the vhost, then follows the "real" location
	 * rules as specified in the configuration.
	 */
	struct lochead	 locations;

	struct aliashead aliases;
	struct proxyhead proxies;
};

struct etm {			/* extension to mime */
	char	 mime[MEDIATYPE_TYPEMAX];
	char	 ext[MEDIATYPE_NAMEMAX];
};

struct mime {
	struct etm	*t;
	size_t		 len;
	size_t		 cap;
};

TAILQ_HEAD(pkihead, pki);
struct pki {
	char		*hash;
	EVP_PKEY	*pkey;
	TAILQ_ENTRY(pki) pkis;
};

struct conf {
	struct privsep	*ps;
	uint32_t	 protos;
	struct mime	 mime;
	char		 chroot[PATH_MAX];
	char		 user[LOGIN_NAME_MAX];
	int		 prefork;
	int		 reload;
	int		 log_syslog;
	int		 log_facility;
	char		*log_access;
	enum log_format	 log_format;
	int		 use_privsep_crypto;
	int		 conftest;

	struct fcgihead	 fcgi;
	struct vhosthead hosts;
	struct pkihead	 pkis;
	struct addrhead	 addrs;
};

extern const char *config_path;

extern int servpipes[PROC_MAX_INSTANCES];
extern int privsep_process;

typedef void (imsg_handlerfn)(struct imsgbuf*, struct imsg*, size_t);

enum {
	REQUEST_UNDECIDED,
	REQUEST_FILE,
	REQUEST_DIR,
	REQUEST_FCGI,
	REQUEST_PROXY,
	REQUEST_DONE,
};

enum proto {
	PROTO_V4,
	PROTO_V6,
	PROTO_UNKNOWN,
};

struct proxy_protocol_v1 {
	enum proto		 proto;
	struct sockaddr_storage	 srcaddr;
	socklen_t		 srclen;
	struct sockaddr_storage	 dstaddr;
	socklen_t		 dstlen;
	uint16_t		 srcport;
	uint16_t		 dstport;
};

#define BUFLAYER_MAX 108

struct buflayer {
	char data[BUFLAYER_MAX];
	size_t len;
	size_t read_pos;
	int has_tail;
};

struct client {
	struct conf		*conf;
	struct address		*addr;
	int 			 proxy_proto;
	struct buflayer		 buf;
	uint32_t		 id;
	struct tls		*ctx;
	char			*req;
	size_t			 reqlen;
	struct iri		 iri;
	char			 domain[DOMAIN_NAME_LEN];
	char			 rhost[NI_MAXHOST];
	char			 rserv[NI_MAXSERV];

	struct bufferevent *bev;

	int		 type;

	struct bufferevent *cgibev;

	struct proxy	*proxy;
	struct bufferevent *proxybev;
	struct tls	*proxyctx;
	int		 proxyevset;
	struct event	 proxyev;

	char		*header;

	int		 code;
	const char	*meta;
	int		 fd, pfd;
	struct dirent	**dir;
	int		 dirlen, diroff;

	/* big enough to store STATUS + SPACE + META + CRLF */
	char		 sbuf[1029];
	size_t		 soff;

	struct sockaddr_storage	 raddr;
	socklen_t		 raddrlen;

	struct vhost	*host;	/* host they're talking to */
	size_t		 loc;	/* location matched */

	SPLAY_ENTRY(client) entry;
};
SPLAY_HEAD(client_tree_id, client);
extern struct client_tree_id clients;

struct connreq {
	char	host[NI_MAXHOST];
	char	port[NI_MAXSERV];
	int	flag;
};

enum imsg_type {
	IMSG_LOG_REQUEST,
	IMSG_LOG_ACCESS,
	IMSG_LOG_SYSLOG,
	IMSG_LOG_FACILITY,

	IMSG_RECONF_START,
	IMSG_RECONF_LOG_FMT,
	IMSG_RECONF_MIME,
	IMSG_RECONF_PROTOS,
	IMSG_RECONF_SOCK,
	IMSG_RECONF_FCGI,
	IMSG_RECONF_HOST,
	IMSG_RECONF_CERT,
	IMSG_RECONF_KEY,
	IMSG_RECONF_OCSP,
	IMSG_RECONF_HOST_ADDR,
	IMSG_RECONF_LOC,
	IMSG_RECONF_ENV,
	IMSG_RECONF_ALIAS,
	IMSG_RECONF_PROXY,
	IMSG_RECONF_PROXY_CERT,
	IMSG_RECONF_PROXY_KEY,
	IMSG_RECONF_END,
	IMSG_RECONF_DONE,

	IMSG_CRYPTO_RSA_PRIVENC,
	IMSG_CRYPTO_RSA_PRIVDEC,
	IMSG_CRYPTO_ECDSA_SIGN,

	IMSG_CTL_PROCFD,
};

/* gmid.c / ge.c */
void		 log_request(struct client *, int, const char *);

/* config.c */
struct conf	*config_new(void);
void		 config_purge(struct conf *);
int		 config_send(struct conf *);
int		 config_recv(struct conf *, struct imsg *);
int		 config_test(struct conf *);

/* crypto.c */
void		 crypto(struct privsep *, struct privsep_proc *);
void		 crypto_engine_init(struct conf *);

/* parse.y */
int		 parse_conf(struct conf *, const char*);
int		 cmdline_symset(char *);

/* mime.c */
void		 init_mime(struct mime*);
int		 add_mime(struct mime*, const char*, const char*);
int		 load_default_mime(struct mime*);
void		 sort_mime(struct mime *);
const char	*mime(struct conf *, struct vhost*, const char*);
void		 free_mime(struct mime *);

/* server.c */
const char	*vhost_lang(struct vhost*, const char*);
const char	*vhost_default_mime(struct vhost*, const char*);
const char	*vhost_index(struct vhost*, const char*);
int		 vhost_auto_index(struct vhost*, const char*);
int		 vhost_block_return(struct vhost*, const char*, int*, const char**);
struct location	*vhost_fastcgi(struct vhost*, const char*);
int		 vhost_dirfd(struct vhost*, const char*, size_t*);
int		 vhost_strip(struct vhost*, const char*);
X509_STORE	*vhost_require_ca(struct vhost*, const char*);
int		 vhost_disable_log(struct vhost*, const char*);

void		 mark_nonblock(int);
void		 client_write(struct bufferevent *, void *);
int		 start_reply(struct client*, int, const char*);
void		 client_close(struct client *);
void		 server_accept(int, short, void *);
void		 server_init(struct privsep *, struct privsep_proc *, void *);
int		 server_configure_done(struct conf *);
void		 server(struct privsep *ps, struct privsep_proc *);

int		 client_tree_cmp(struct client *, struct client *);
SPLAY_PROTOTYPE(client_tree_id, client, entry, client_tree_cmp);

/* dirs.c */
int		 scandir_fd(int, struct dirent***, int(*)(const struct dirent*),
		    int(*)(const struct dirent**, const struct dirent**));
int		 select_non_dot(const struct dirent*);
int		 select_non_dotdot(const struct dirent*);

/* fcgi.c */
void		 fcgi_read(struct bufferevent *, void *);
void		 fcgi_write(struct bufferevent *, void *);
void		 fcgi_error(struct bufferevent *, short, void *);
void		 fcgi_req(struct client *, struct location *);

/* sandbox.c */
void		 sandbox_main_process(void);
void		 sandbox_server_process(void);
void		 sandbox_crypto_process(void);
void		 sandbox_logger_process(void);

/* utf8.c */
int		 valid_multibyte_utf8(struct parser*);
char		*utf8_nth(char*, size_t);

/* logger.c */
void		 logger(struct privsep *, struct privsep_proc *);

/* proxy.c */
int		 proxy_init(struct client *);

/* puny.c */
int		 puny_decode(const char*, char*, size_t, const char**);

/* utils.c */
const char	*strip_path(const char *, int);
int		 ends_with(const char*, const char*);
char		*absolutify_path(const char*);
char		*xstrdup(const char*);
void		*xcalloc(size_t, size_t);
void		 gencert(const char *, const char *, const char *, int);
X509_STORE	*load_ca(uint8_t *, size_t);
int		 validate_against_ca(X509_STORE*, const uint8_t*, size_t);
void		 ssl_error(const char *);
char		*ssl_pubkey_hash(const uint8_t *, size_t);
EVP_PKEY	*ssl_load_pkey(const uint8_t *, size_t);
struct vhost	*new_vhost(void);
struct location	*new_location(void);
struct proxy	*new_proxy(void);

/* proxy-proto.c */
int proxy_proto_v1_parse(struct proxy_protocol_v1 *, char *, size_t, size_t *);
int proxy_proto_v1_string(const struct proxy_protocol_v1 *, char*, size_t);

#endif