LwipIntf.cpp

extern "C" {
#include "lwip/err.h"
#include "lwip/ip_addr.h"
#include "lwip/dns.h"
#include "lwip/dhcp.h"
#include "lwip/init.h" // LWIP_VERSION_
#if LWIP_IPV6
#include "lwip/netif.h" // struct netif
#endif

#include <user_interface.h>
}

#include "debug.h"
#include "LwipIntf.h"

// args      | esp order    arduino order
// ----      + ---------    -------------
// local_ip  | local_ip     local_ip
// arg1      | gateway      dns1
// arg2      | netmask      gateway
// arg3      | dns1         netmask
//
// result stored into gateway/netmask/dns1

bool LwipIntf::ipAddressReorder(const IPAddress& local_ip, const IPAddress& arg1, const IPAddress& arg2, const IPAddress& arg3,
                                IPAddress& gateway, IPAddress& netmask, IPAddress& dns1)
{
    //To allow compatibility, check first octet of 3rd arg. If 255, interpret as ESP order, otherwise Arduino order.
    gateway = arg1;
    netmask = arg2;
    dns1 = arg3;

    if (netmask[0] != 255)
    {
        //octet is not 255 => interpret as Arduino order
        gateway = arg2;
        netmask = arg3[0] == 0 ? IPAddress(255, 255, 255, 0) : arg3; //arg order is arduino and 4th arg not given => assign it arduino default
        dns1 = arg1;
    }

    // check whether all is IPv4 (or gateway not set)
    if (!(local_ip.isV4() && netmask.isV4() && (!gateway.isSet() || gateway.isV4())))
    {
        return false;
    }

    //ip and gateway must be in the same netmask
    if (gateway.isSet() && (local_ip.v4() & netmask.v4()) != (gateway.v4() & netmask.v4()))
    {
        return false;
    }

    return true;
}

/**
    Get ESP8266 station DHCP hostname
    @return hostname
*/
String LwipIntf::hostname(void)
{
    return wifi_station_get_hostname();
}

/**
    Get ESP8266 station DHCP hostname
    @return hostname
*/
const char* LwipIntf::getHostname(void)
{
    return wifi_station_get_hostname();
}

/**
    Set ESP8266 station DHCP hostname
    @param aHostname max length:24
    @return ok
*/
bool LwipIntf::hostname(const char* aHostname)
{
    /*
        vvvv RFC952 vvvv
        ASSUMPTIONS
        1. A "name" (Net, Host, Gateway, or Domain name) is a text string up
        to 24 characters drawn from the alphabet (A-Z), digits (0-9), minus
        sign (-), and period (.).  Note that periods are only allowed when
        they serve to delimit components of "domain style names". (See
        RFC-921, "Domain Name System Implementation Schedule", for
        background).  No blank or space characters are permitted as part of a
        name. No distinction is made between upper and lower case.  The first
        character must be an alpha character.  The last character must not be
        a minus sign or period.  A host which serves as a GATEWAY should have
        "-GATEWAY" or "-GW" as part of its name.  Hosts which do not serve as
        Internet gateways should not use "-GATEWAY" and "-GW" as part of
        their names. A host which is a TAC should have "-TAC" as the last
        part of its host name, if it is a DoD host.  Single character names
        or nicknames are not allowed.
        ^^^^ RFC952 ^^^^

        - 24 chars max
        - only a..z A..Z 0..9 '-'
        - no '-' as last char
    */

    size_t len = strlen(aHostname);

    if (len == 0 || len > 32)
    {
        // nonos-sdk limit is 32
        // (dhcp hostname option minimum size is ~60)
        DEBUGV("WiFi.(set)hostname(): empty or large(>32) name\n");
        return false;
    }

    // check RFC compliance
    bool compliant = (len <= 24);
    for (size_t i = 0; compliant && i < len; i++)
        if (!isalnum(aHostname[i]) && aHostname[i] != '-')
        {
            compliant = false;
        }
    if (aHostname[len - 1] == '-')
    {
        compliant = false;
    }

    if (!compliant)
    {
        DEBUGV("hostname '%s' is not compliant with RFC952\n", aHostname);
    }

    bool ret = wifi_station_set_hostname(aHostname);
    if (!ret)
    {
        DEBUGV("WiFi.hostname(%s): wifi_station_set_hostname() failed\n", aHostname);
        return false;
    }

    // now we should inform dhcp server for this change, using lwip_renew()
    // looping through all existing interface
    // harmless for AP, also compatible with ethernet adapters (to come)
    for (netif* intf = netif_list; intf; intf = intf->next)
    {

        // unconditionally update all known interfaces
        intf->hostname = wifi_station_get_hostname();

        if (netif_dhcp_data(intf) != nullptr)
        {
            // renew already started DHCP leases
            err_t lwipret = dhcp_renew(intf);
            if (lwipret != ERR_OK)
            {
                DEBUGV("WiFi.hostname(%s): lwIP error %d on interface %c%c (index %d)\n",
                       intf->hostname, (int)lwipret, intf->name[0], intf->name[1], intf->num);
                ret = false;
            }
        }
    }

    return ret && compliant;
}