30 lines
832 B
C++
30 lines
832 B
C++
#pragma once
|
|
#include <cstdint>
|
|
#include "eth.h"
|
|
#include "ipv4.h"
|
|
|
|
namespace udp {
|
|
|
|
struct __attribute__((packed)) header {
|
|
uint16_t src_port;
|
|
uint16_t dst_port;
|
|
uint16_t length;
|
|
uint16_t checksum;
|
|
};
|
|
static_assert(sizeof(header) == 8);
|
|
|
|
template <typename Buf>
|
|
void prepend(Buf& buf, const eth::mac_addr& dst_mac, const eth::mac_addr& src_mac,
|
|
ipv4::ip4_addr src_ip, ipv4::ip4_addr dst_ip,
|
|
uint16_t src_port, uint16_t dst_port,
|
|
size_t payload_len, uint8_t ttl = 64) {
|
|
auto* u = buf.template prepend<header>();
|
|
u->src_port = src_port;
|
|
u->dst_port = dst_port;
|
|
u->length = __builtin_bswap16(sizeof(header) + payload_len);
|
|
u->checksum = 0;
|
|
ipv4::prepend(buf, dst_mac, src_mac, src_ip, dst_ip, 17, sizeof(header) + payload_len, ttl);
|
|
}
|
|
|
|
} // namespace udp
|