From b517121f1c143780bccd380879fe7b96681b0f89 Mon Sep 17 00:00:00 2001
From: Ralf Ramsauer <ralf@ramses-pyramidenbau.de>
Date: Sat, 11 Mar 2017 15:04:26 -0800
Subject: [PATCH] base encoder: simplify structures

We don't need complex getters. Just expose basic operations as they are.

Signed-off-by: Ralf Ramsauer <ralf@ramses-pyramidenbau.de>
---
 src/base128.c | 35 +++++++++++-----------------
 src/base128.h |  2 +-
 src/base32.c  | 35 +++++++++++-----------------
 src/base32.h  |  4 ++--
 src/base64.c  | 35 +++++++++++-----------------
 src/base64.h  |  2 +-
 src/client.c  | 42 ++++++++++++---------------------
 src/iodined.c | 64 ++++++++++++++++++++++-----------------------------
 8 files changed, 86 insertions(+), 133 deletions(-)

diff --git a/src/base128.c b/src/base128.c
index 8f926ed..30b6034 100644
--- a/src/base128.c
+++ b/src/base128.c
@@ -52,28 +52,6 @@ static const unsigned char cb128[] =
 static unsigned char rev128[256];
 static int reverse_init = 0;
 
-static int base128_encode(char *, size_t *, const void *, size_t);
-static int base128_decode(void *, size_t *, const char *, size_t);
-static int base128_handles_dots(void);
-static int base128_blksize_raw(void);
-static int base128_blksize_enc(void);
-
-static struct encoder base128_encoder =
-{
-	"Base128",
-	base128_encode,
-	base128_decode,
-	base128_handles_dots,
-	base128_handles_dots,
-	base128_blksize_raw,
-	base128_blksize_enc
-};
-
-struct encoder *get_base128_encoder(void)
-{
-	return &base128_encoder;
-}
-
 static int base128_handles_dots(void)
 {
 	return 0;
@@ -284,3 +262,16 @@ static int base128_decode(void *buf, size_t *buflen, const char *str,
 
 	return iout;
 }
+
+const struct encoder base128_ops = {
+	.name = "Base128",
+
+	.encode = base128_encode,
+	.decode = base128_decode,
+
+	.places_dots = base128_handles_dots,
+	.eats_dots = base128_handles_dots,
+
+	.blocksize_raw = base128_blksize_raw,
+	.blocksize_encoded = base128_blksize_enc
+};
diff --git a/src/base128.h b/src/base128.h
index f4c55f6..f967134 100644
--- a/src/base128.h
+++ b/src/base128.h
@@ -17,6 +17,6 @@
 #ifndef __BASE128_H__
 #define __BASE128_H__
 
-struct encoder *get_base128_encoder(void);
+const struct encoder base128_ops;
 
 #endif
diff --git a/src/base32.c b/src/base32.c
index bf540eb..809115a 100644
--- a/src/base32.c
+++ b/src/base32.c
@@ -33,28 +33,6 @@ static const char cb32_ucase[] =
 static unsigned char rev32[256];
 static int reverse_init = 0;
 
-static int base32_encode(char *, size_t *, const void *, size_t);
-static int base32_decode(void *, size_t *, const char *, size_t);
-static int base32_handles_dots(void);
-static int base32_blksize_raw(void);
-static int base32_blksize_enc(void);
-
-static struct encoder base32_encoder =
-{
-	"Base32",
-	base32_encode,
-	base32_decode,
-	base32_handles_dots,
-	base32_handles_dots,
-	base32_blksize_raw,
-	base32_blksize_enc
-};
-
-struct encoder *get_base32_encoder(void)
-{
-	return &base32_encoder;
-}
-
 static int base32_handles_dots(void)
 {
 	return 0;
@@ -261,3 +239,16 @@ static int base32_decode(void *buf, size_t *buflen, const char *str,
 
 	return iout;
 }
+
+const struct encoder base32_ops = {
+	.name = "Base32",
+
+	.encode = base32_encode,
+	.decode = base32_decode,
+
+	.places_dots = base32_handles_dots,
+	.eats_dots = base32_handles_dots,
+
+	.blocksize_raw = base32_blksize_raw,
+	.blocksize_encoded = base32_blksize_enc,
+};
diff --git a/src/base32.h b/src/base32.h
index 83ba784..89f78ad 100644
--- a/src/base32.h
+++ b/src/base32.h
@@ -18,8 +18,8 @@
 #ifndef __BASE32_H__
 #define __BASE32_H__
 
-struct encoder *get_base32_encoder(void);
-
 int b32_5to8(int);
 int b32_8to5(int);
+
+extern const struct encoder base32_ops;
 #endif
diff --git a/src/base64.c b/src/base64.c
index 133fcb4..875c8c9 100644
--- a/src/base64.c
+++ b/src/base64.c
@@ -33,28 +33,6 @@ static const char cb64[] =
 static unsigned char rev64[256];
 static int reverse_init = 0;
 
-static int base64_encode(char *, size_t *, const void *, size_t);
-static int base64_decode(void *, size_t *, const char *, size_t);
-static int base64_handles_dots(void);
-static int base64_blksize_raw(void);
-static int base64_blksize_enc(void);
-
-static struct encoder base64_encoder =
-{
-	"Base64",
-	base64_encode,
-	base64_decode,
-	base64_handles_dots,
-	base64_handles_dots,
-	base64_blksize_raw,
-	base64_blksize_enc
-};
-
-struct encoder *get_base64_encoder(void)
-{
-	return &base64_encoder;
-}
-
 static int base64_handles_dots(void)
 {
 	return 0;
@@ -199,3 +177,16 @@ static int base64_decode(void *buf, size_t *buflen, const char *str,
 
 	return iout;
 }
+
+const struct encoder base64_ops = {
+	.name = "Base64",
+
+	.encode = base64_encode,
+	.decode = base64_decode,
+
+	.places_dots = base64_handles_dots,
+	.eats_dots = base64_handles_dots,
+
+	.blocksize_raw = base64_blksize_raw,
+	.blocksize_encoded = base64_blksize_enc,
+};
diff --git a/src/base64.h b/src/base64.h
index 8ce4742..376ea2d 100644
--- a/src/base64.h
+++ b/src/base64.h
@@ -18,6 +18,6 @@
 #ifndef __BASE64_H__
 #define __BASE64_H__
 
-struct encoder *get_base64_encoder(void);
+extern const struct encoder base64_ops;
 
 #endif
diff --git a/src/client.c b/src/client.c
index ea243fb..db792c1 100644
--- a/src/client.c
+++ b/src/client.c
@@ -85,16 +85,9 @@ static uint16_t chunkid;
 static uint16_t chunkid_prev;
 static uint16_t chunkid_prev2;
 
-/* Base32 encoder used for non-data packets and replies */
-static struct encoder *b32;
-/* Base64 etc encoders for replies */
-static struct encoder *b64;
-static struct encoder *b64u;
-static struct encoder *b128;
-
 /* The encoder used for data packets
  * Defaults to Base32, can be changed after handshake */
-static struct encoder *dataenc;
+const static struct encoder *dataenc = &base32_ops;
 
 /* The encoder to use for downstream data */
 static char downenc = ' ';
@@ -117,11 +110,6 @@ void
 client_init()
 {
 	running = 1;
-	b32 = get_base32_encoder();
-	b64 = get_base64_encoder();
-	b64u = get_base64u_encoder();
-	b128 = get_base128_encoder();
-	dataenc = get_base32_encoder();
 	rand_seed = ((unsigned int) rand()) & 0xFFFF;
 	send_ping_soon = 1;	/* send ping immediately after startup */
 	conn = CONN_DNS_NULL;
@@ -342,7 +330,7 @@ send_packet(int fd, char cmd, const char *data, const size_t datalen)
 	buf[0] = cmd;
 
 	build_hostname(buf + 1, sizeof(buf) - 1, data, datalen, topdomain,
-		       b32, hostname_maxlen);
+		       &base32_ops, hostname_maxlen);
 	send_query(fd, buf);
 }
 
@@ -480,7 +468,7 @@ dns_namedec(char *outdata, int outdatalen, char *buf, int buflen)
 
 		/* this also does undotify */
 		return unpack_data(outdata, outdatalen, buf + 1, buflen - 4,
-				   b32);
+				   &base32_ops);
 
 	case 'i': /* Hostname++ with base64 */
 	case 'I':
@@ -490,7 +478,7 @@ dns_namedec(char *outdata, int outdatalen, char *buf, int buflen)
 
 		/* this also does undotify */
 		return unpack_data(outdata, outdatalen, buf + 1, buflen - 4,
-				   b64);
+				   &base64_ops);
 
 	case 'j': /* Hostname++ with base64u */
 	case 'J':
@@ -500,7 +488,7 @@ dns_namedec(char *outdata, int outdatalen, char *buf, int buflen)
 
 		/* this also does undotify */
 		return unpack_data(outdata, outdatalen, buf + 1, buflen - 4,
-				   b64u);
+				   &base64u_ops);
 
 	case 'k': /* Hostname++ with base128 */
 	case 'K':
@@ -510,35 +498,35 @@ dns_namedec(char *outdata, int outdatalen, char *buf, int buflen)
 
 		/* this also does undotify */
 		return unpack_data(outdata, outdatalen, buf + 1, buflen - 4,
-				   b128);
+				   &base128_ops);
 
 	case 't': /* plain base32(Thirty-two) from TXT */
 	case 'T':
 		if (buflen < 2)
 			return 0;
 
-		return b32->decode(outdata, &outdatalenu, buf + 1, buflen - 1);
+		return base32_ops.decode(outdata, &outdatalenu, buf + 1, buflen - 1);
 
 	case 's': /* plain base64(Sixty-four) from TXT */
 	case 'S':
 		if (buflen < 2)
 			return 0;
 
-		return b64->decode(outdata, &outdatalenu, buf + 1, buflen - 1);
+		return base64_ops.decode(outdata, &outdatalenu, buf + 1, buflen - 1);
 
 	case 'u': /* plain base64u (Underscore) from TXT */
 	case 'U':
 		if (buflen < 2)
 			return 0;
 
-		return b64u->decode(outdata, &outdatalenu, buf + 1, buflen - 1);
+		return base64_ops.decode(outdata, &outdatalenu, buf + 1, buflen - 1);
 
 	case 'v': /* plain base128 from TXT */
 	case 'V':
 		if (buflen < 2)
 			return 0;
 
-		return b128->decode(outdata, &outdatalenu, buf + 1, buflen - 1);
+		return base128_ops.decode(outdata, &outdatalenu, buf + 1, buflen - 1);
 
 	case 'r': /* Raw binary from TXT */
 	case 'R':
@@ -2020,16 +2008,16 @@ handshake_switch_codec(int dns_fd, int bits)
 	char in[4096];
 	int i;
 	int read;
-	struct encoder *tempenc;
+	const struct encoder *tempenc;
 
 	if (bits == 5)
-		tempenc = get_base32_encoder();
+		tempenc = &base32_ops;
 	else if (bits == 6)
-		tempenc = get_base64_encoder();
+		tempenc = &base64_ops;
 	else if (bits == 26)	/* "2nd" 6 bits per byte, with underscore */
-		tempenc = get_base64u_encoder();
+		tempenc = &base64u_ops;
 	else if (bits == 7)
-		tempenc = get_base128_encoder();
+		tempenc = &base128_ops;
 	else return;
 
 	fprintf(stderr, "Switching upstream to codec %s\n", tempenc->name);
diff --git a/src/iodined.c b/src/iodined.c
index bd5afdb..534325f 100644
--- a/src/iodined.c
+++ b/src/iodined.c
@@ -87,10 +87,6 @@ WSADATA wsa_data;
 static int running = 1;
 static char *topdomain;
 static char password[33];
-static struct encoder *b32;
-static struct encoder *b64;
-static struct encoder *b64u;
-static struct encoder *b128;
 static int created_users;
 
 static int check_ip;
@@ -478,7 +474,7 @@ static inline void save_to_qmem_pingordata(int userid, struct query *q)
 
 		/* We already unpacked in handle_null_request(), but that's
 		   lost now... Note: b32 directly, we want no undotify here! */
-		i = b32->decode(cmc, &cmcsize, q->name + 1, (cp - q->name) - 1);
+		i = base32_ops.decode(cmc, &cmcsize, q->name + 1, (cp - q->name) - 1);
 
 		if (i < 4)
 			return;	 /* illegal ping; shouldn't happen */
@@ -796,7 +792,7 @@ handle_null_request(int tun_fd, int dns_fd, struct dnsfd *dns_fds, struct query
 	if(in[0] == 'V' || in[0] == 'v') {
 		int version = 0;
 
-		read = unpack_data(unpacked, sizeof(unpacked), &(in[1]), domain_len - 1, b32);
+		read = unpack_data(unpacked, sizeof(unpacked), &(in[1]), domain_len - 1, &base32_ops);
 		/* Version greeting, compare and send ack/nak */
 		if (read > 4) {
 			/* Received V + 32bits version */
@@ -817,7 +813,7 @@ handle_null_request(int tun_fd, int dns_fd, struct dnsfd *dns_fds, struct query
 				users[userid].hostlen = q->fromlen;
 
 				memcpy(&(users[userid].q), q, sizeof(struct query));
-				users[userid].encoder = get_base32_encoder();
+				users[userid].encoder = &base32_ops;
 				users[userid].downenc = 'T';
 				send_version_response(dns_fd, VERSION_ACK, users[userid].seed, userid, q);
 				syslog(LOG_INFO, "accepted version for user #%d from %s",
@@ -872,7 +868,7 @@ handle_null_request(int tun_fd, int dns_fd, struct dnsfd *dns_fds, struct query
 		}
 		return;
 	} else if(in[0] == 'L' || in[0] == 'l') {
-		read = unpack_data(unpacked, sizeof(unpacked), &(in[1]), domain_len - 1, b32);
+		read = unpack_data(unpacked, sizeof(unpacked), &(in[1]), domain_len - 1, &base32_ops);
 		if (read < 17) {
 			write_dns(dns_fd, q, "BADLEN", 6, 'T');
 			return;
@@ -954,7 +950,8 @@ handle_null_request(int tun_fd, int dns_fd, struct dnsfd *dns_fds, struct query
 		return;
 	} else if(in[0] == 'S' || in[0] == 's') {
 		int codec;
-		struct encoder *enc;
+		const struct encoder *enc;
+
 		if (domain_len < 3) { /* len at least 3, example: "S15" */
 			write_dns(dns_fd, q, "BADLEN", 6, 'T');
 			return;
@@ -971,22 +968,22 @@ handle_null_request(int tun_fd, int dns_fd, struct dnsfd *dns_fds, struct query
 
 		switch (codec) {
 		case 5: /* 5 bits per byte = base32 */
-			enc = get_base32_encoder();
+			enc = &base32_ops;
 			user_switch_codec(userid, enc);
 			write_dns(dns_fd, q, enc->name, strlen(enc->name), users[userid].downenc);
 			break;
 		case 6: /* 6 bits per byte = base64 */
-			enc = get_base64_encoder();
+			enc = &base64_ops;
 			user_switch_codec(userid, enc);
 			write_dns(dns_fd, q, enc->name, strlen(enc->name), users[userid].downenc);
 			break;
 		case 26: /* "2nd" 6 bits per byte = base64u, with underscore */
-			enc = get_base64u_encoder();
+			enc = &base64u_ops;
 			user_switch_codec(userid, enc);
 			write_dns(dns_fd, q, enc->name, strlen(enc->name), users[userid].downenc);
 			break;
 		case 7: /* 7 bits per byte = base128 */
-			enc = get_base128_encoder();
+			enc = &base128_ops;
 			user_switch_codec(userid, enc);
 			write_dns(dns_fd, q, enc->name, strlen(enc->name), users[userid].downenc);
 			break;
@@ -1157,7 +1154,7 @@ handle_null_request(int tun_fd, int dns_fd, struct dnsfd *dns_fds, struct query
 	} else if(in[0] == 'N' || in[0] == 'n') {
 		int max_frag_size;
 
-		read = unpack_data(unpacked, sizeof(unpacked), &(in[1]), domain_len - 1, b32);
+		read = unpack_data(unpacked, sizeof(unpacked), &(in[1]), domain_len - 1, &base32_ops);
 
 		if (read < 3) {
 			write_dns(dns_fd, q, "BADLEN", 6, 'T');
@@ -1193,7 +1190,7 @@ handle_null_request(int tun_fd, int dns_fd, struct dnsfd *dns_fds, struct query
 		if (q->id == 0)
 			return;
 
-		read = unpack_data(unpacked, sizeof(unpacked), &(in[1]), domain_len - 1, b32);
+		read = unpack_data(unpacked, sizeof(unpacked), &(in[1]), domain_len - 1, &base32_ops);
 		if (read < 4)
 			return;
 
@@ -2143,31 +2140,31 @@ write_dns_nameenc(char *buf, size_t buflen, const char *data, int datalen, char
 
 	if (downenc == 'S') {
 		buf[0] = 'i';
-		if (!b64->places_dots())
+		if (!base64_ops.places_dots())
 			space -= (space / 57);	/* space for dots */
-		b64->encode(buf+1, &space, data, datalen);
-		if (!b64->places_dots())
+		base64_ops.encode(buf+1, &space, data, datalen);
+		if (!base64_ops.places_dots())
 			inline_dotify(buf, buflen);
 	} else if (downenc == 'U') {
 		buf[0] = 'j';
-		if (!b64u->places_dots())
+		if (!base64u_ops.places_dots())
 			space -= (space / 57);	/* space for dots */
-		b64u->encode(buf+1, &space, data, datalen);
-		if (!b64u->places_dots())
+		base64u_ops.encode(buf+1, &space, data, datalen);
+		if (!base64u_ops.places_dots())
 			inline_dotify(buf, buflen);
 	} else if (downenc == 'V') {
 		buf[0] = 'k';
-		if (!b128->places_dots())
+		if (!base128_ops.places_dots())
 			space -= (space / 57);	/* space for dots */
-		b128->encode(buf+1, &space, data, datalen);
-		if (!b128->places_dots())
+		base128_ops.encode(buf+1, &space, data, datalen);
+		if (!base128_ops.places_dots())
 			inline_dotify(buf, buflen);
 	} else {
 		buf[0] = 'h';
-		if (!b32->places_dots())
+		if (!base32_ops.places_dots())
 			space -= (space / 57);	/* space for dots */
-		b32->encode(buf+1, &space, data, datalen);
-		if (!b32->places_dots())
+		base32_ops.encode(buf+1, &space, data, datalen);
+		if (!base32_ops.places_dots())
 			inline_dotify(buf, buflen);
 	}
 
@@ -2238,15 +2235,15 @@ write_dns(int fd, struct query *q, const char *data, int datalen, char downenc)
 
 		if (downenc == 'S') {
 			txtbuf[0] = 's';	/* plain base64(Sixty-four) */
-			len = b64->encode(txtbuf+1, &space, data, datalen);
+			len = base64_ops.encode(txtbuf+1, &space, data, datalen);
 		}
 		else if (downenc == 'U') {
 			txtbuf[0] = 'u';	/* Base64 with Underscore */
-			len = b64u->encode(txtbuf+1, &space, data, datalen);
+			len = base64u_ops.encode(txtbuf+1, &space, data, datalen);
 		}
 		else if (downenc == 'V') {
 			txtbuf[0] = 'v';	/* Base128 */
-			len = b128->encode(txtbuf+1, &space, data, datalen);
+			len = base128_ops.encode(txtbuf+1, &space, data, datalen);
 		}
 		else if (downenc == 'R') {
 			txtbuf[0] = 'r';	/* Raw binary data */
@@ -2254,7 +2251,7 @@ write_dns(int fd, struct query *q, const char *data, int datalen, char downenc)
 			memcpy(txtbuf + 1, data, len);
 		} else {
 			txtbuf[0] = 't';	/* plain base32(Thirty-two) */
-			len = b32->encode(txtbuf+1, &space, data, datalen);
+			len = base32_ops.encode(txtbuf+1, &space, data, datalen);
 		}
 		len = dns_encode(buf, sizeof(buf), q, QR_ANSWER, txtbuf, len+1);
 	} else {
@@ -2417,11 +2414,6 @@ main(int argc, char **argv)
 	netmask = 27;
 	pidfile = NULL;
 
-	b32 = get_base32_encoder();
-	b64 = get_base64_encoder();
-	b64u = get_base64u_encoder();
-	b128 = get_base128_encoder();
-
 	retval = 0;
 
 #ifdef WINDOWS32