https://pubs.opengroup.org/onlinepubs/007908799/xns/socket.html

https://docs.espressif.com/projects/esp-idf/en/stable/esp32/api-guides/lwip.html#bsd-sockets-api

setsockopt()
    SO_REUSEADDR
    SO_BROADCAST
    SO_NO_CHECK ?


/* Socket protocol types (TCP/UDP/RAW) */
SOCK_RAW        3

struct raw_pcb * raw_new        (u8_t proto);
err_t            raw_connect    (struct raw_pcb *pcb, const ip_addr_t *ipaddr);
void             raw_disconnect (struct raw_pcb *pcb);
err_t            raw_bind       (struct raw_pcb *pcb, const ip_addr_t *ipaddr);
err_t            raw_sendto     (struct raw_pcb *pcb, struct pbuf *p, const ip_addr_t *ipaddr);
err_t            raw_send       (struct raw_pcb *pcb, struct pbuf *p);\
void             raw_recv       (struct raw_pcb *pcb, raw_recv_fn recv, void *recv_arg);



int addr_family = AF_INET;
int ip_protocol = 0;

https://lwip.fandom.com/wiki/Netconn_send




// socket(addr type (v6/v4) (AF_INET/AF_INET6),
//                            proto type (SOCK_STREAM (tcp)/SOCK_DGRAM (udp)/SOCK_RAW (raw)),
//                            ip protocol (IPPROTO_IP/IPPROTO_IPV6));

#include <string.h>
#include <sys/param.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/event_groups.h"
#include "esp_system.h"
#include "esp_event.h"
#include "esp_log.h"
#include "nvs_flash.h"
#include "esp_netif.h"
#include "protocol_examples_common.h"

#include "lwip/err.h"
#include "lwip/sockets.h"
#include "lwip/sys.h"
#include <lwip/netdb.h>

#define HOST_IP_ADDR "10.0.0.255"
#define PORT CONFIG_EXAMPLE_PORT 4444 // placeholder

int err;
int errno;
int sockfd;

static const char *payload = "Message from ESP32 ";
static const char* TAG = "PrincessPiError";

struct sockaddr_in dest_addr;
dest_addr.sin_addr.s_addr = inet_addr(HOST_IP_ADDR);
dest_addr.sin_family = AF_INET;
dest_addr.sin_port = htons(PORT);
int opt = 1;

// https://pubs.opengroup.org/onlinepubs/007908799/xns/socket.html
// https://docs.espressif.com/projects/esp-idf/en/stable/esp32/api-guides/lwip.html#bsd-sockets-api
if(sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_IP) < 0) {
    ESP_LOGE(TAG, "%d", errno);
}

setsockopt(sockfd, SOL_SOCKET, SO_BROADCAST, &opt, sizeof(opt));
setsockopt(sockfd, SOL_SOCKET, SO_ERROR, &err, &optlen);

if(err < 0) {
    ESP_LOGE(TAG, "%d", err);
}

// sendto(sockefd, payloadf, strlen(payload), 0, IP_ADDR_BROADCAST, sizeof(IP_ADDR_BROADCAST));
sendto(sockfd, payload, strlen(payload), 0, (struct sockaddr *)&dest_addr, sizeof(dest_addr));

// setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,  &opt, sizeof(opt));
/*

#define TNetConn struct netconn *
#define TNetBuf  struct netbuf  *

TNetConn netConn = netconn_new(NETCONN_RAW);

struct TIpAddr xIp;
xIp.addr = 10.0.0.1;

TNetBuf xNetBuf = netbuf_new();
xBuf = netbuf_alloc(xNetBuf, 0x100);
netconn_sendto(netConn, xBuf, IP_ADDR_BROADCAST, 4444);

//Pointer xBuf = mem_malloc(0x100); // Pointer type? huh I'm too high for this

// netbuf_alloc (newNetBuf, 0x100);
// memset(xBuf, 0xAA, 0x100);
// xBuf = "\x00\x00\xFF" // raw payload. need memcpy?


//netbuf_ref()
// netconn_sendto(connection, payload, dst ip, port)
// netconn_sendto(newNetconn, xBuf, xIP, );
// netconn_sendto(newNetconn, &newNetbuff);

*/