*/void ppp_send_config(    int unit,     int mtu,    u32_t asyncmap,    int pcomp,     int accomp){    PPPControl *pc = &pppControl[unit];    int i;        pc->mtu = mtu;    pc->pcomp = pcomp;    pc->accomp = accomp;        /* Load the ACCM bits for the 32 control codes. */    for (i = 0; i < 32/8; i++)        pc->outACCM[i] = (u_char)((asyncmap >> (8 * i)) & 0xFF);    PPPDEBUG((LOG_INFO, "ppp_send_config[%d]: outACCM=%X %X %X %X\n",                unit,                pc->outACCM[0], pc->outACCM[1], pc->outACCM[2], pc->outACCM[3]));}/* * ppp_set_xaccm - set the extended transmit ACCM for the interface. */void ppp_set_xaccm(int unit, ext_accm *accm){    memcpy(pppControl[unit].outACCM, accm, sizeof(ext_accm));    PPPDEBUG((LOG_INFO, "ppp_set_xaccm[%d]: outACCM=%X %X %X %X\n",                unit,                pppControl[unit].outACCM[0],                pppControl[unit].outACCM[1],                pppControl[unit].outACCM[2],                pppControl[unit].outACCM[3]));}/* * ppp_recv_config - configure the receive-side characteristics of * the ppp interface. */void ppp_recv_config(    int unit,     int mru,    u32_t asyncmap,    int pcomp,     int accomp){    PPPControl *pc = &pppControl[unit];    int i;    	(void)accomp;	(void)pcomp;	(void)mru;    /* Load the ACCM bits for the 32 control codes. */    for (i = 0; i < 32 / 8; i++)        pc->inACCM[i] = (u_char)(asyncmap >> (i * 8));    PPPDEBUG((LOG_INFO, "ppp_recv_config[%d]: inACCM=%X %X %X %X\n",                unit,                pc->inACCM[0], pc->inACCM[1], pc->inACCM[2], pc->inACCM[3]));}#if 0/* * ccp_test - ask kernel whether a given compression method * is acceptable for use.  Returns 1 if the method and parameters * are OK, 0 if the method is known but the parameters are not OK * (e.g. code size should be reduced), or -1 if the method is unknown. */int ccp_test(    int unit,     int opt_len,     int for_transmit,    u_char *opt_ptr){    return 0;   /* XXX Currently no compression. */}/* * ccp_flags_set - inform kernel about the current state of CCP. */void ccp_flags_set(int unit, int isopen, int isup){    /* XXX */}/* * ccp_fatal_error - returns 1 if decompression was disabled as a * result of an error detected after decompression of a packet, * 0 otherwise.  This is necessary because of patent nonsense. */int ccp_fatal_error(int unit){    /* XXX */    return 0;}#endif/* * get_idle_time - return how long the link has been idle. */int get_idle_time(int u, struct ppp_idle *ip){       /* XXX */	(void)u;	(void)ip;    return 0;}/* * Return user specified netmask, modified by any mask we might determine * for address `addr' (in network byte order). * Here we scan through the system's list of interfaces, looking for * any non-point-to-point interfaces which might appear to be on the same * network as `addr'.  If we find any, we OR in their netmask to the * user-specified netmask. */u32_t GetMask(u32_t addr){    u32_t mask, nmask;        htonl(addr);    if (IN_CLASSA(addr))    /* determine network mask for address class */        nmask = IN_CLASSA_NET;    else if (IN_CLASSB(addr))        nmask = IN_CLASSB_NET;    else        nmask = IN_CLASSC_NET;    /* class D nets are disallowed by bad_ip_adrs */    mask = subnetMask | htonl(nmask);        /* XXX     * Scan through the system's network interfaces.     * Get each netmask and OR them into our mask.     */        return mask;}/* * sifvjcomp - config tcp header compression */int sifvjcomp(    int pd,     int vjcomp,     int cidcomp,     int maxcid){#if VJ_SUPPORT > 0    PPPControl *pc = &pppControl[pd];        pc->vjEnabled = vjcomp;    pc->vjComp.compressSlot = cidcomp;    pc->vjComp.maxSlotIndex = maxcid;    PPPDEBUG((LOG_INFO, "sifvjcomp: VJ compress enable=%d slot=%d max slot=%d\n",                vjcomp, cidcomp, maxcid));#endif    return 0;}/* * pppifNetifInit - netif init callback */static err_t pppifNetifInit(struct netif *netif){	netif->name[0] = 'p';	netif->name[1] = 'p';	netif->output = pppifOutput;	netif->mtu = pppMTU((int)netif->state);	return ERR_OK;}/* * sifup - Config the interface up and enable IP packets to pass. */int sifup(int pd){    PPPControl *pc = &pppControl[pd];    int st = 1;        if (pd < 0 || pd >= NUM_PPP || !pc->openFlag) {        st = 0;        PPPDEBUG((LOG_WARNING, "sifup[%d]: bad parms\n", pd));    } else {		netif_remove(&pc->netif);		if (netif_add(&pc->netif, &pc->addrs.our_ipaddr, &pc->addrs.netmask, &pc->addrs.his_ipaddr, (void *)pd, pppifNetifInit, ip_input)) {        		pc->if_up = 1;        		pc->errCode = PPPERR_NONE;			PPPDEBUG((LOG_DEBUG, "sifup: unit %d: linkStatusCB=%lx errCode=%d\n", pd, pc->linkStatusCB, pc->errCode));			if(pc->linkStatusCB)				pc->linkStatusCB(pc->linkStatusCtx, pc->errCode, &pc->addrs);		} else {        	st = 0;        	PPPDEBUG((LOG_ERR, "sifup[%d]: netif_add failed\n", pd));		}    }    return st;}/* * sifnpmode - Set the mode for handling packets for a given NP. */int sifnpmode(int u, int proto, enum NPmode mode){	(void)u;	(void)proto;	(void)mode;    return 0;}/* * sifdown - Config the interface down and disable IP. */int sifdown(int pd){    PPPControl *pc = &pppControl[pd];    int st = 1;        if (pd < 0 || pd >= NUM_PPP || !pc->openFlag) {        st = 0;        PPPDEBUG((LOG_WARNING, "sifdown[%d]: bad parms\n", pd));    } else {        pc->if_up = 0;	netif_remove(&pc->netif);	PPPDEBUG((LOG_DEBUG, "sifdown: unit %d: linkStatusCB=%lx errCode=%d\n", pd, pc->linkStatusCB, pc->errCode));	if(pc->linkStatusCB)		pc->linkStatusCB(pc->linkStatusCtx, PPPERR_CONNECT, NULL);	}    return st;}/* * sifaddr - Config the interface IP addresses and netmask. */int sifaddr(    int pd,             /* Interface unit ??? */    u32_t o,        /* Our IP address ??? */    u32_t h,        /* His IP address ??? */    u32_t m,        /* IP subnet mask ??? */    u32_t ns1,      /* Primary DNS */    u32_t ns2       /* Secondary DNS */){    PPPControl *pc = &pppControl[pd];    int st = 1;        if (pd < 0 || pd >= NUM_PPP || !pc->openFlag) {        st = 0;        PPPDEBUG((LOG_WARNING, "sifup[%d]: bad parms\n", pd));    } else {		memcpy(&pc->addrs.our_ipaddr, &o, sizeof(o));		memcpy(&pc->addrs.his_ipaddr, &h, sizeof(h));		memcpy(&pc->addrs.netmask, &m, sizeof(m));		memcpy(&pc->addrs.dns1, &ns1, sizeof(ns1));		memcpy(&pc->addrs.dns2, &ns2, sizeof(ns2));    }    return st;}/* * cifaddr - Clear the interface IP addresses, and delete routes * through the interface if possible. */int cifaddr(    int pd,         /* Interface unit ??? */    u32_t o,    /* Our IP address ??? */    u32_t h     /* IP broadcast address ??? */){    PPPControl *pc = &pppControl[pd];    int st = 1;    	(void)o;	(void)h;    if (pd < 0 || pd >= NUM_PPP || !pc->openFlag) {        st = 0;        PPPDEBUG((LOG_WARNING, "sifup[%d]: bad parms\n", pd));    } else {		IP4_ADDR(&pc->addrs.our_ipaddr, 0,0,0,0);		IP4_ADDR(&pc->addrs.his_ipaddr, 0,0,0,0);		IP4_ADDR(&pc->addrs.netmask, 255,255,255,0);		IP4_ADDR(&pc->addrs.dns1, 0,0,0,0);		IP4_ADDR(&pc->addrs.dns2, 0,0,0,0);    }    return st;}/* * sifdefaultroute - assign a default route through the address given. */int sifdefaultroute(int pd, u32_t l, u32_t g){    PPPControl *pc = &pppControl[pd];    int st = 1;    	(void)l;	(void)g;    if (pd < 0 || pd >= NUM_PPP || !pc->openFlag) {        st = 0;        PPPDEBUG((LOG_WARNING, "sifup[%d]: bad parms\n", pd));    } else {		netif_set_default(&pc->netif);    }    /* TODO: check how PPP handled the netMask, previously not set by ipSetDefault */    return st;}/* * cifdefaultroute - delete a default route through the address given. */int cifdefaultroute(int pd, u32_t l, u32_t g){    PPPControl *pc = &pppControl[pd];    int st = 1;    	(void)l;	(void)g;    if (pd < 0 || pd >= NUM_PPP || !pc->openFlag) {        st = 0;        PPPDEBUG((LOG_WARNING, "sifup[%d]: bad parms\n", pd));    } else {		netif_set_default(NULL);    }    return st;}voidpppMainWakeup(int pd){	PPPDEBUG((LOG_DEBUG, "pppMainWakeup: unit %d\n", pd));	sio_read_abort(pppControl[pd].fd);}/* these callbacks are necessary because lcp_* functions   must be called in the same context as pppInput(),   namely the tcpip_thread(), essentially because   they manipulate timeouts which are thread-private*/static voidpppStartCB(void *arg){    int pd = (int)arg;	PPPDEBUG((LOG_DEBUG, "pppStartCB: unit %d\n", pd));    lcp_lowerup(pd);    lcp_open(pd);      /* Start protocol */}static voidpppStopCB(void *arg){    int pd = (int)arg;	PPPDEBUG((LOG_DEBUG, "pppStopCB: unit %d\n", pd));    lcp_close(pd, "User request");}static voidpppHupCB(void *arg){    int pd = (int)arg;	PPPDEBUG((LOG_DEBUG, "pppHupCB: unit %d\n", pd));    lcp_lowerdown(pd);    link_terminated(pd);}/**********************************//*** LOCAL FUNCTION DEFINITIONS ***//**********************************//* The main PPP process function.  This implements the state machine according * to section 4 of RFC 1661: The Point-To-Point Protocol. */static void pppMain(void *arg){    int pd = (int)arg;    struct pbuf *p;    PPPControl* pc;    pc = &pppControl[pd];    p = pbuf_alloc(PBUF_RAW, PPP_MRU+PPP_HDRLEN, PBUF_RAM);    if(!p) {		LWIP_ASSERT("p != NULL", p);		pc->errCode = PPPERR_ALLOC;		goto out;    }    /*     * Start the connection and handle incoming events (packet or timeout).     */