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ie: Adding IE builder support

These functions can be used to create IE TLV messages.
This commit is contained in:
Jukka Rissanen 2014-07-25 15:45:56 +03:00 committed by Denis Kenzior
parent 8cb16f41a8
commit b90d914a3f
2 changed files with 127 additions and 0 deletions

104
src/ie.c
View File

@ -74,3 +74,107 @@ bool ie_tlv_iter_next(struct ie_tlv_iter *iter)
return true;
}
#define TLV_HEADER_LEN 2
static bool ie_tlv_builder_init_recurse(struct ie_tlv_builder *builder,
unsigned char *tlv, unsigned int size)
{
if (!builder)
return false;
if (!tlv) {
memset(builder->buf, 0, MAX_BUILDER_SIZE);
builder->tlv = builder->buf;
builder->max = MAX_BUILDER_SIZE;
} else {
builder->tlv = tlv;
builder->max = size;
}
builder->pos = 0;
builder->parent = NULL;
builder->tag = 0xffff;
builder->len = 0;
return true;
}
bool ie_tlv_builder_init(struct ie_tlv_builder *builder)
{
return ie_tlv_builder_init_recurse(builder, NULL, 0);
}
static void ie_tlv_builder_write_header(struct ie_tlv_builder *builder)
{
unsigned char *tlv = builder->tlv + builder->pos;
tlv[0] = builder->tag;
tlv[1] = builder->len;
}
bool ie_tlv_builder_set_length(struct ie_tlv_builder *builder,
unsigned int new_len)
{
unsigned int new_pos = builder->pos + TLV_HEADER_LEN + new_len;
if (new_pos > builder->max)
return false;
if (builder->parent)
ie_tlv_builder_set_length(builder->parent, new_pos);
builder->len = new_len;
return true;
}
bool ie_tlv_builder_next(struct ie_tlv_builder *builder, unsigned int new_tag)
{
if (new_tag > 0xff)
return false;
if (builder->tag != 0xffff) {
ie_tlv_builder_write_header(builder);
builder->pos += TLV_HEADER_LEN + builder->len;
}
if (!ie_tlv_builder_set_length(builder, 0))
return false;
builder->tag = new_tag;
return true;
}
unsigned char *ie_tlv_builder_get_data(struct ie_tlv_builder *builder)
{
return builder->tlv + TLV_HEADER_LEN + builder->pos;
}
bool ie_tlv_builder_recurse(struct ie_tlv_builder *builder,
struct ie_tlv_builder *recurse)
{
unsigned char *end = builder->buf + builder->max;
unsigned char *data = ie_tlv_builder_get_data(builder);
if (!ie_tlv_builder_init_recurse(recurse, data, end - data))
return false;
recurse->parent = builder;
return true;
}
void ie_tlv_builder_finalize(struct ie_tlv_builder *builder,
unsigned int *out_len)
{
unsigned int len;
ie_tlv_builder_write_header(builder);
len = builder->pos + TLV_HEADER_LEN + builder->len;
if (out_len)
*out_len = len;
}

View File

@ -163,9 +163,32 @@ struct ie_tlv_iter {
const unsigned char *data;
};
#define MAX_BUILDER_SIZE (8 * 1024)
struct ie_tlv_builder {
unsigned char buf[MAX_BUILDER_SIZE];
unsigned int max;
unsigned int pos;
unsigned char *tlv;
struct ie_tlv_builder *parent;
unsigned int tag;
unsigned int len;
};
void ie_tlv_iter_init(struct ie_tlv_iter *iter, const unsigned char *tlv,
unsigned int len);
void ie_tlv_iter_recurse(struct ie_tlv_iter *iter,
struct ie_tlv_iter *recurse);
unsigned int ie_tlv_iter_get_tag(struct ie_tlv_iter *iter);
bool ie_tlv_iter_next(struct ie_tlv_iter *iter);
bool ie_tlv_builder_init(struct ie_tlv_builder *builder);
bool ie_tlv_builder_set_length(struct ie_tlv_builder *builder,
unsigned int new_len);
bool ie_tlv_builder_next(struct ie_tlv_builder *builder, unsigned int new_tag);
unsigned char *ie_tlv_builder_get_data(struct ie_tlv_builder *builder);
bool ie_tlv_builder_recurse(struct ie_tlv_builder *builder,
struct ie_tlv_builder *recurse);
void ie_tlv_builder_finalize(struct ie_tlv_builder *builder,
unsigned int *out_len);