common: Moving some bech32 related utilities to bech32_util

These were so far only used for bolt11 construction, but we'll need them for the
DNS seed as well, so here we just pull them out into their own unit and prefix
them.

Signed-off-by: Christian Decker <decker.christian@gmail.com>

common/Makefile

@@ -1,5 +1,6 @@
 COMMON_SRC_NOGEN :=				\
 	common/bech32.c				\
+	common/bech32_util.c			\
 	common/bip32.c				\
 	common/bolt11.c				\
 	common/channel_config.c			\

common/bech32_util.c

@@ -0,0 +1,25 @@
+#include "bech32_util.h"
+#include <ccan/tal/tal.h>
+
+static u8 get_bit(const u8 *src, size_t bitoff)
+{
+        return ((src[bitoff / 8] >> (7 - (bitoff % 8))) & 1);
+}
+
+void bech32_push_bits(u5 **data, const void *src, size_t nbits)
+{
+        size_t i, b;
+        size_t data_len = tal_len(*data);
+
+        for (i = 0; i < nbits; i += b) {
+                tal_resize(data, data_len+1);
+                (*data)[data_len] = 0;
+                for (b = 0; b < 5; b++) {
+                        (*data)[data_len] <<= 1;
+                        /* If we need bits we don't have, zero */
+                        if (i+b < nbits)
+                                (*data)[data_len] |= get_bit(src, i+b);
+                }
+                data_len++;
+        }
+}

common/bech32_util.h

@@ -0,0 +1,13 @@
+#ifndef LIGHTNING_COMMON_BECH32_UTIL_H
+#define LIGHTNING_COMMON_BECH32_UTIL_H
+#include "config.h"
+
+#include <ccan/short_types/short_types.h>
+#include <common/hash_u5.h>
+
+/**
+ * Push the bytes in src in 5 bit format onto the end of data.
+ */
+void bech32_push_bits(u5 **data, const void *src, size_t nbits);
+
+#endif /* LIGHTNING_COMMON_BECH32_UTIL_H */

common/bolt11.c

@@ -8,6 +8,7 @@
 #include <ccan/structeq/structeq.h>
 #include <ccan/tal/str/str.h>
 #include <common/bech32.h>
+#include <common/bech32_util.h>
 #include <common/bolt11.h>
 #include <common/utils.h>
 #include <errno.h>
@@ -700,35 +701,11 @@ struct bolt11 *bolt11_decode(const tal_t *ctx, const char *str,
         return b11;
 }
 
-static u8 get_bit(const u8 *src, size_t bitoff)
-{
-        return ((src[bitoff / 8] >> (7 - (bitoff % 8))) & 1);
-}
-
-/* Returns now many u5s were appended. */
-static void push_bits(u5 **data, const void *src, size_t nbits)
-{
-        size_t i, b;
-        size_t data_len = tal_len(*data);
-
-        for (i = 0; i < nbits; i += b) {
-                tal_resize(data, data_len+1);
-                (*data)[data_len] = 0;
-                for (b = 0; b < 5; b++) {
-                        (*data)[data_len] <<= 1;
-                        /* If we need bits we don't have, zero */
-                        if (i+b < nbits)
-                                (*data)[data_len] |= get_bit(src, i+b);
-                }
-                data_len++;
-        }
-}
-
 /* Helper for pushing a variable-length big-endian int. */
 static void push_varlen_uint(u5 **data, u64 val, size_t nbits)
 {
         be64 be_val = cpu_to_be64(val << (64 - nbits));
-        push_bits(data, &be_val, nbits);
+        bech32_push_bits(data, &be_val, nbits);
 }
 
 /* BOLT #11:
@@ -744,7 +721,7 @@ static void push_field(u5 **data, char type, const void *src, size_t nbits)
         assert(bech32_charset_rev[(unsigned char)type] >= 0);
         push_varlen_uint(data, bech32_charset_rev[(unsigned char)type], 5);
         push_varlen_uint(data, (nbits + 4) / 5, 10);
-        push_bits(data, src, nbits);
+        bech32_push_bits(data, src, nbits);
 }
 
 /* BOLT #11:
@@ -781,7 +758,7 @@ static void push_fallback_addr(u5 **data, u5 version, const void *addr, u16 addr
         push_varlen_uint(data, bech32_charset_rev[(unsigned char)'f'], 5);
         push_varlen_uint(data, ((5 + addr_len * CHAR_BIT) + 4) / 5, 10);
         push_varlen_uint(data, version, 5);
-        push_bits(data, addr, addr_len * CHAR_BIT);
+        bech32_push_bits(data, addr, addr_len * CHAR_BIT);
 }
 
 static void encode_p(u5 **data, const struct sha256 *hash)
@@ -974,7 +951,7 @@ char *bolt11_encode_(const tal_t *ctx,
                 &rsig);
         sig_and_recid[64] = recid;
 
-        push_bits(&data, sig_and_recid, sizeof(sig_and_recid) * CHAR_BIT);
+        bech32_push_bits(&data, sig_and_recid, sizeof(sig_and_recid) * CHAR_BIT);
 
         output = tal_arr(ctx, char, strlen(hrp) + tal_count(data) + 8);
         if (!bech32_encode(output, hrp, data, tal_count(data), (size_t)-1))

common/test/run-bolt11.c

@@ -1,4 +1,5 @@
 #include "../bech32.c"
+#include "../bech32_util.c"
 #include "../bolt11.c"
 #include "../hash_u5.c"
 #include <ccan/err/err.h>

devtools/Makefile

@@ -5,6 +5,7 @@ DEVTOOLS_TOOL_OBJS := $(DEVTOOLS_TOOL_SRC:.c=.o)
 
 DEVTOOLS_COMMON_OBJS :=				\
 	common/bech32.o				\
+	common/bech32_util.o			\
 	common/bolt11.o				\
 	common/hash_u5.o			\
 	common/type_to_string.o			\

gossipd/Makefile

@@ -36,6 +36,8 @@ LIGHTNINGD_HEADERS_GEN += $(LIGHTNINGD_GOSSIP_HEADERS)
 
 # Common source we use.
 GOSSIPD_COMMON_OBJS :=				\
+	common/bech32.o				\
+	common/bech32_util.o			\
 	common/bip32.o				\
 	common/crypto_state.o			\
 	common/crypto_sync.o			\

lightningd/Makefile

@@ -15,6 +15,7 @@ default: lightningd-all
 # Common source we use.
 LIGHTNINGD_COMMON_OBJS :=			\
 	common/bech32.o				\
+	common/bech32_util.o			\
 	common/bip32.o				\
 	common/bolt11.o				\
 	common/channel_config.o			\