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#include <assert.h>
#include <network/bytes.h>
#include <network/ipv4.h>
#include <network/udp.h>
#include <socket.h>
void send_udp_packet(struct sockaddr_in *src, const struct sockaddr_in *dst,
const uint8_t *payload, uint16_t payload_length) {
uint16_t header[4] = {0};
header[0] = src->sin_port;
header[1] = dst->sin_port;
header[2] = htons(payload_length + 8);
uint16_t packet_length = sizeof(header) + payload_length;
uint8_t *packet = kmalloc(packet_length);
memcpy(packet, header, sizeof(header));
memcpy(packet + sizeof(header), payload, payload_length);
send_ipv4_packet(dst->sin_addr.s_addr, 0x11, packet, packet_length);
kfree(packet);
}
void handle_udp(uint8_t src_ip[4], const uint8_t *payload,
uint32_t packet_length) {
assert(packet_length >= 8);
// n_.* means network format(big endian)
// h_.* means host format((probably) little endian)
uint16_t n_source_port = *(uint16_t *)payload;
uint16_t h_source_port = ntohs(n_source_port);
(void)h_source_port;
uint16_t h_dst_port = ntohs(*(uint16_t *)(payload + 2));
uint16_t h_length = ntohs(*(uint16_t *)(payload + 4));
assert(h_length == packet_length);
uint16_t data_length = h_length - 8;
const uint8_t *data = payload + 8;
// Find the open port
OPEN_INET_SOCKET *in_s = find_open_udp_port(htons(h_dst_port));
assert(in_s);
SOCKET *s = in_s->s;
vfs_fd_t *fifo_file = s->ptr_socket_fd;
// Write the sockaddr struct such that it can later be
// given to userland if asked.
struct sockaddr_in /*{
sa_family_t sin_family;
union {
uint32_t s_addr;
} sin_addr;
uint16_t sin_port;
}*/ in;
in.sin_family = AF_INET;
memcpy(&in.sin_addr.s_addr, src_ip, sizeof(uint32_t));
in.sin_port = n_source_port;
socklen_t sock_length = sizeof(struct sockaddr_in);
raw_vfs_pwrite(fifo_file, &sock_length, sizeof(sock_length), 0);
raw_vfs_pwrite(fifo_file, &in, sizeof(in), 0);
// Write the UDP payload length(not including header)
raw_vfs_pwrite(fifo_file, &data_length, sizeof(uint16_t), 0);
// Write the UDP payload
raw_vfs_pwrite(fifo_file, (char *)data, data_length, 0);
}
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