1 files changed, 181 insertions, 0 deletions
diff --git a/channels/misdn/asn1.c b/channels/misdn/asn1.c
new file mode 100644
index 000000000..80dcacd64
--- /dev/null
+++ b/channels/misdn/asn1.c
@@ -0,0 +1,181 @@
+
+#include "asn1.h"
+#include <string.h>
+
+/*
+** ASN.1 Encoding
+*/
+
+int _enc_null (__u8 *dest, int tag)
+{
+	dest[0] = tag;
+	dest[1] = 0;
+	return 2;
+}
+
+int _enc_bool (__u8 *dest, __u32 i, int tag)
+{
+	dest[0] = tag;
+	dest[1] = 1;
+	dest[2] = i ? 1:0;
+	return 3;
+}
+
+int _enc_int (__u8 *dest, __u32 i, int tag)
+{
+	__u8 *p;
+	dest[0] = tag;
+	p = &dest[2];
+	do {
+		*p++ = i;
+		i >>= 8;
+	} while (i);
+	dest[1] = p - &dest[2];
+	return p - dest;
+}
+
+int _enc_enum (__u8 *dest, __u32 i, int tag)
+{
+	__u8 *p;
+
+	dest[0] = tag;
+	p = &dest[2];
+	do {
+		*p++ = i;
+		i >>= 8;
+	} while (i);
+	dest[1] = p - &dest[2];
+	return p - dest;
+}
+
+int _enc_num_string (__u8 *dest, __u8 *nd, __u8 len, int tag)
+{
+	__u8 *p;
+	int i;
+
+	dest[0] = tag;
+	p = &dest[2];
+	for (i = 0; i < len; i++)
+		*p++ = *nd++;
+	dest[1] = p - &dest[2];
+	return p - dest;
+}
+
+int _enc_sequence_start (__u8 *dest, __u8 **id, int tag)
+{
+	dest[0] = tag;
+	*id = &dest[1];
+	return 2;
+}
+
+int _enc_sequence_end (__u8 *dest, __u8 *id, int tag_dummy)
+{
+	*id = dest - id - 1;
+	return 0;
+}
+
+/*
+** ASN.1 Decoding
+*/
+
+#define CHECK_P 						\
+	do { \
+		if (p >= end) \
+			return -1; \
+	} while (0) 
+
+#define CallASN1(ret, p, end, todo)		\
+	do { \
+		ret = todo; \
+		if (ret < 0) { \
+			return -1; \
+		} \
+		p += ret; \
+	} while (0)
+
+#define INIT 							\
+	int len, ret; \
+	__u8 *begin = p; \
+	if (tag) \
+		*tag = *p; \
+	p++; \
+	CallASN1(ret, p, end, dec_len(p, &len)); \
+	if (len >= 0) { \
+		if (p + len > end) \
+			return -1; \
+		end = p + len; \
+	}
+
+int _dec_null (__u8 *p, __u8 *end, int *tag)
+{
+	INIT;
+	return p - begin;
+}
+
+int _dec_bool (__u8 *p, __u8 *end, int *i, int *tag)
+{
+	INIT;
+	*i = 0;
+	while (len--) {
+		CHECK_P;
+		*i = (*i >> 8) + *p;
+		p++;
+	}
+	return p - begin;
+}
+
+int _dec_int (__u8 *p, __u8 *end, int *i, int *tag)
+{
+	INIT;
+
+	*i = 0;
+	while (len--) {
+		CHECK_P;
+		*i = (*i << 8) + *p;
+		p++;
+	}
+	return p - begin;
+}
+
+int _dec_enum (__u8 *p, __u8 *end, int *i, int *tag)
+{
+	INIT;
+
+	*i = 0;
+	while (len--) {
+		CHECK_P;
+		*i = (*i << 8) + *p;
+		p++;
+	}
+	return p - begin;
+}
+
+int _dec_num_string (__u8 *p, __u8 *end, char *str, int *tag)
+{
+	INIT;
+
+	while (len--) {
+		CHECK_P;
+		*str++ = *p;
+		p++;
+	}
+	*str = 0;
+	return p - begin;
+}
+
+int _dec_octet_string (__u8 *p, __u8 *end, char *str, int *tag)
+{
+	return _dec_num_string(p, end, str, tag);
+}
+
+int _dec_sequence (__u8 *p, __u8 *end, int *tag)
+{
+	INIT;
+	return p - begin;
+}
+
+int dec_len (__u8 *p, int *len)
+{
+	*len = *p;
+	return 1;
+}