0
0
mirror of https://gitlab.nic.cz/labs/bird.git synced 2024-12-23 02:01:55 +00:00
bird/lib/cbor.c
Katerina Kubecova 9f27bfc6fc Porting the CBOR encoder from the YANG branch
Minor cleanups by commiter.

(source commit 43ff10204b but expected
to be rebased later, don't worry if you fail to find it)
2024-10-01 14:26:00 +02:00

238 lines
6.3 KiB
C

#include <stdint.h>
#include <string.h>
#include "lib/cbor.h"
void write_item(struct cbor_writer *writer, uint8_t major, uint64_t num);
void check_memory(struct cbor_writer *writer, int add_size);
struct cbor_writer *cbor_init(uint8_t *buff, uint32_t capacity, struct linpool *lp)
{
struct cbor_writer *writer = (struct cbor_writer*)lp_alloc(lp, sizeof(struct cbor_writer));
writer->cbor = buff;
writer->capacity = capacity;
writer->pt = 0;
writer->lp = lp;
return writer;
}
void cbor_open_block(struct cbor_writer *writer) { // We will need to close the block later manualy
check_memory(writer, 2);
writer->cbor[writer->pt] = 0xbf;
writer->pt++;
}
void cbor_open_list(struct cbor_writer *writer)
{
check_memory(writer, 2);
writer->cbor[writer->pt] = 0x9f;
writer->pt++;
}
void cbor_close_block_or_list(struct cbor_writer *writer)
{
check_memory(writer, 2);
writer->cbor[writer->pt] = 0xff;
writer->pt++;
}
void cbor_open_block_with_length(struct cbor_writer *writer, uint32_t length)
{
write_item(writer, 5, length);
}
void cbor_open_list_with_length(struct cbor_writer *writer, uint32_t length)
{
write_item(writer, 4, length);
}
void cbor_add_int(struct cbor_writer *writer, int64_t item)
{
if (item >= 0)
{
write_item(writer, 0, item); // 0 is the "major" (three bits) introducing positive int, 1 is for negative
}
else
{
write_item(writer, 1, -item - 1);
}
}
void cbor_epoch_time(struct cbor_writer *writer, int64_t time, int shift)
{
write_item(writer, 6, 1); // 6 is TAG, 1 is tag number for epoch time
cbor_relativ_time(writer, time, shift);
}
void cbor_relativ_time(struct cbor_writer *writer, int64_t time, int shift)
{
write_item(writer, 6, 4); // 6 is TAG, 4 is tag number for decimal fraction
cbor_open_list_with_length(writer, 2);
cbor_add_int(writer, shift);
cbor_add_int(writer, time);
}
void cbor_add_ipv4(struct cbor_writer *writer, ip4_addr addr)
{
write_item(writer, 6, 52); // 6 is TAG, 52 is tag number for ipv4
write_item(writer, 2, 4); // bytestring of length 4
put_ip4(&writer->cbor[writer->pt], addr);
writer->pt += 4;
}
void cbor_add_ipv6(struct cbor_writer *writer, ip6_addr addr)
{
write_item(writer, 6, 54); // 6 is TAG, 54 is tag number for ipv6
write_item(writer, 2, 16); // bytestring of length 16
put_ip6(&writer->cbor[writer->pt], addr);
writer->pt += 16;
}
void cbor_add_ipv4_prefix(struct cbor_writer *writer, net_addr_ip4 *n)
{
write_item(writer, 6, 52); // 6 is TAG, 52 is tag number for ipv4
cbor_open_block_with_length(writer, 2);
cbor_add_int(writer, n->pxlen);
write_item(writer, 2, 4); // bytestring of length 4
put_ip4(&writer->cbor[writer->pt], n->prefix);
writer->pt += 4;
}
void cbor_add_ipv6_prefix(struct cbor_writer *writer, net_addr_ip6 *n)
{
write_item(writer, 6, 54); // 6 is TAG, 54 is tag number for ipv6
cbor_open_block_with_length(writer, 2);
cbor_add_int(writer, n->pxlen);
write_item(writer, 2, 16);
put_ip6(&writer->cbor[writer->pt], n->prefix);
writer->pt += 16;
}
void cbor_add_uint(struct cbor_writer *writer, uint64_t item)
{
write_item(writer, 0, item);
}
void cbor_add_tag(struct cbor_writer *writer, int item)
{
write_item(writer, 6, item);
}
void cbor_add_string(struct cbor_writer *writer, const char *string)
{
int length = strlen(string);
write_item(writer, 3, length); // 3 is major, then goes length of string and string
check_memory(writer, length);
memcpy(writer->cbor+writer->pt, string, length);
writer->pt+=length;
}
void cbor_nonterminated_string(struct cbor_writer *writer, const char *string, uint32_t length)
{
write_item(writer, 3, length); // 3 is major, then goes length of string and string
check_memory(writer, length);
memcpy(writer->cbor+writer->pt, string, length);
writer->pt+=length;
}
void write_item(struct cbor_writer *writer, uint8_t major, uint64_t num)
{
//log("write major %i %li", major, num);
major = major<<5;
check_memory(writer, 10);
if (num > ((uint64_t)1<<(4*8))-1)
{ // We need 8 bytes to encode the num
major += 0x1b; // reserving those bytes
writer->cbor[writer->pt] = major;
writer->pt++;
for (int i = 7; i>=0; i--)
{ // write n-th byte of num
uint8_t to_write = (num>>(i*8)) & 0xff;
writer->cbor[writer->pt] = to_write;
writer->pt++;
}
return;
}
if (num > (1<<(2*8))-1)
{ // We need 4 bytes to encode the num
major += 0x1a; // reserving those bytes
writer->cbor[writer->pt] = major;
writer->pt++;
for (int i = 3; i>=0; i--)
{ // write n-th byte of num
uint8_t to_write = (num>>(i*8)) & 0xff;
writer->cbor[writer->pt] = to_write;
writer->pt++;
}
return;
}
if (num > (1<<(8))-1)
{ // We need 2 bytes to encode the num
major += 0x19; // reserving those bytes
writer->cbor[writer->pt] = major;
writer->pt++;
for (int i = 1; i>=0; i--)
{ // write n-th byte of num
uint8_t to_write = (num>>(i*8)) & 0xff;
writer->cbor[writer->pt] = to_write;
writer->pt++;
}
return;
}
if (num > 23)
{ // byte is enough, but aditional value would be too big
major += 0x18; // reserving that byte
writer->cbor[writer->pt] = major;
writer->pt++;
uint8_t to_write = num & 0xff;
writer->cbor[writer->pt] = to_write;
writer->pt++;
return;
}
//log("write item major %i num %i writer->pt %i writer->capacity %i writer %i", major, num, writer->pt, writer->capacity, writer);
major += num; // we can store the num as additional value
writer->cbor[writer->pt] = major;
writer->pt++;
}
void cbor_write_item_with_constant_val_length_4(struct cbor_writer *writer, uint8_t major, uint64_t num)
{
// this is only for headers which should be constantly long.
major = major<<5;
check_memory(writer, 10);
major += 0x1a; // reserving those bytes
writer->cbor[writer->pt] = major;
writer->pt++;
for (int i = 3; i>=0; i--)
{ // write n-th byte of num
uint8_t to_write = (num>>(i*8)) & 0xff;
writer->cbor[writer->pt] = to_write;
writer->pt++;
}
}
void rewrite_4bytes_int(struct cbor_writer *writer, int pt, int num)
{
for (int i = 3; i>=0; i--)
{
uint8_t to_write = (num>>(i*8)) & 0xff;
writer->cbor[pt] = to_write;
pt++;
}
}
void check_memory(struct cbor_writer *writer, int add_size)
{
if (writer->capacity - writer->pt-add_size < 0)
{
bug("There is not enough space for cbor response in given buffer");
}
}