File content as of revision 88:135fb4bb7aac:

#pragma once 

/* ----------------------------------------------------------------
   APN stands for Access Point Name, a setting on your modem or phone
   that identifies an external network your phone can access for data 
   (e.g., 3G or 4G Internet service on your phone). 
   
   The APN settings can be forced when calling the join function.
   Below is a list of known APNs that us used if no apn config 
   is forced. This list could be extended by other settings.
   
   For further reading:
   wiki apn: http://en.wikipedia.org/wiki/Access_Point_Name
   wiki mcc/mnc: http://en.wikipedia.org/wiki/Mobile_country_code
   google: https://www.google.de/search?q=APN+list   
---------------------------------------------------------------- */

//! helper to generate the APN string
#define _APN(apn,username,password) apn "\0" username "\0" password "\0"

//! helper to extract a field from the config string 
#define _APN_GET(cfg) \
    *cfg ? cfg : ""; \
    cfg  += strlen(cfg) + 1
                    
//! APN lookup struct
typedef struct { 
    const char* mccmnc; //!< mobile country code (MCC) and mobile network code MNC  
    const char* cfg;    //!< APN configuartion string, use _APN macro to generate
} APN_t;

//! default APN settings used by many networks
static const char* apndef = _APN("internet",,); 

//! this is a list of special APNs for different network operators 
static const APN_t apnlut[] = {
// MCC Country
//  { /* Operator */ "MCC-MNC[,MNC]" _APN(APN,USERNAME,PASSWORD) },
// MCC must be 3 digits
// MNC must be either 2 or 3 digits

// 262 Germany 
    { /* T-Mobile */ "262-01",  _APN("internet.t-mobile","t-mobile","tm") },

// 222 Italy
    { /* TIM */      "222-01",  _APN("ibox.tim.it",,) },
    { /* Vodafone */ "222-10",  _APN("web.omnitel.it",,) },

// 228 Switzerland
    { /* Swisscom */ "228-01",  _APN("gprs.swisscom.ch",,) },
    { /* Orange */   "228-03",  _APN("internet",,) /* contract */ 
                                _APN("click",,)    /* pre-pay */ },

// 234 United Kingdom - GB
    { /* O2 */       "234-02,10,11",
                                _APN("mobile.o2.co.uk","faster","web") /* contract */
                                _APN("mobile.o2.co.uk","bypass","web") /* pre-pay */ 
                                _APN("payandgo.o2.co.uk","payandgo","payandgo") },
    { /* Vodafone */ "234-15",  _APN("internet","web","web")          /* contract */
                                _APN("pp.vodafone.co.uk","wap","wap")  /* pre-pay */ },

// 310 USA
    { /* T-Mobile */ "310-026,260,490",
                                _APN("epc.tmobile.com",,) 
                                _APN("fast.tmobile.com",,) /* LTE */ },
    { /* AT&T */     "310-030,150,170,260,410,560,680",
                                _APN("phone",,)
                                _APN("wap.cingular","WAP@CINGULARGPRS.COM","CINGULAR1")
                                _APN("isp.cingular","ISP@CINGULARGPRS.COM","CINGULAR1") },
};

inline const char* apnconfig(const char* imsi)
{
    const char* config = NULL;
    if (imsi && *imsi) {
        // many carriers use internet without username and password, os use this as default
        // now try to lookup the setting for our table
        for (int i = 0; i < sizeof(apnlut)/sizeof(*apnlut) && !config; i ++) {
            const char* p = apnlut[i].mccmnc;
            // check the MCC
            if ((0 == memcmp(imsi, p, 3))) {
                p += 3;
                // check all the MNC, MNC length can be 2 or 3 digits
                while (((p[0] == '-') || (p[0] == ',')) && 
                        (p[1] >= '0') && (p[1] <= '9') && 
                        (p[2] >= '0') && (p[2] <= '9') && !config) {
                    int l = ((p[3] >= '0') && (p[3] <= '9')) ? 3 : 2;
                    if (0 == memcmp(imsi+3,p+1,l))
                        config = apnlut[i].cfg;
                    p += 1 + l;
                } 
            }
        }
    }
    // use default if not found
    if (!config)
        config = apndef;
    return config;
}