#include "netdebug.h"
#include "netos.h"
/*************************/
/*** LOCAL DEFINITIONS ***/
/*************************/
/*
* Configuration parameters.
*/
#define MAXIDLEFLAG 500 /* Max Xmit idle time before resend flag char. */
#define MAXKILLDELAY TICKSPERSEC /* Max delay jiffys before PPP task checks kill. */
#define STACK_SIZE NETSTACK+512 /* Enough to handle printf's. */
#define MAX_IFS 32
/*
* The basic PPP frame.
*/
#define PPP_HDRLEN 4 /* octets for standard ppp header */
#define PPP_FCSLEN 2 /* octets for FCS */
#define PPP_ADDRESS(p) (((u_char *)(p))[0])
#define PPP_CONTROL(p) (((u_char *)(p))[1])
#define PPP_PROTOCOL(p) ((((u_char *)(p))[2] << 8) + ((u_char *)(p))[3])
/* PPP packet parser states. Current state indicates operation yet to be
* completed. */
typedef enum {
PDIDLE = 0, /* Idle state - waiting. */
PDSTART, /* Process start flag. */
PDADDRESS, /* Process address field. */
PDCONTROL, /* Process control field. */
PDPROTOCOL1, /* Process protocol field 1. */
PDPROTOCOL2, /* Process protocol field 2. */
PDDATA /* Process data byte. */
} PPPDevStates;
/* Special character codes. */
#define PPPFLAG 0x7e /* Flag character. */
#define PPPESCAPE 0x7d /* Escape character. */
#define PPPESCMASK 0x20 /* Mask to x-or with escaped character. */
#define PPPADDRESS 0xff /* All-stations address. */
#define PPPCONTROL 0x03 /* Unnumbered info. */
/*
* Significant octet values.
*/
#define PPP_ALLSTATIONS 0xff /* All-Stations broadcast address */
#define PPP_UI 0x03 /* Unnumbered Information */
#define PPP_FLAG 0x7e /* Flag Sequence */
#define PPP_ESCAPE 0x7d /* Asynchronous Control Escape */
#define PPP_TRANS 0x20 /* Asynchronous transparency modifier */
/*
* Protocol field values.
*/
#define PPP_IP 0x21 /* Internet Protocol */
#define PPP_XNS 0x25 /* Xerox NS */
#define PPP_AT 0x29 /* AppleTalk Protocol */
#define PPP_IPX 0x2b /* IPX Datagram (RFC1552) */
#define PPP_VJC_COMP 0x2d /* VJ compressed TCP */
#define PPP_VJC_UNCOMP 0x2f /* VJ uncompressed TCP */
#define PPP_COMP 0xfd /* compressed packet */
#define PPP_IPCP 0x8021 /* IP Control Protocol */
#define PPP_ATCP 0x8029 /* AppleTalk Control Protocol */
#define PPP_IPXCP 0x802b /* IPX Control Protocol (RFC1552) */
#define PPP_CCP 0x80fd /* Compression Control Protocol */
#define PPP_LCP 0xc021 /* Link Control Protocol */
#define PPP_PAP 0xc023 /* Password Authentication Protocol */
#define PPP_LQR 0xc025 /* Link Quality Report protocol */
#define PPP_CHAP 0xc223 /* Cryptographic Handshake Auth. Protocol */
#define PPP_CBCP 0xc029 /* Callback Control Protocol */
/*
* Values for FCS calculations.
*/
#define PPP_INITFCS 0xffff /* Initial FCS value */
#define PPP_GOODFCS 0xf0b8 /* Good final FCS value */
#define PPP_FCS(fcs, c) (((fcs) >> 8) ^ fcstab[((fcs) ^ (c)) & 0xff])
/*
* Bit definitions for flags.
*/
#define SC_COMP_PROT 0x00000001 /* protocol compression (output) */
#define SC_COMP_AC 0x00000002 /* header compression (output) */
#define SC_COMP_TCP 0x00000004 /* TCP (VJ) compression (output) */
#define SC_NO_TCP_CCID 0x00000008 /* disable VJ connection-id comp. */
#define SC_REJ_COMP_AC 0x00000010 /* reject adrs/ctrl comp. on input */
#define SC_REJ_COMP_TCP 0x00000020 /* reject TCP (VJ) comp. on input */
#define SC_CCP_OPEN 0x00000040 /* Look at CCP packets */
#define SC_CCP_UP 0x00000080 /* May send/recv compressed packets */
#define SC_DEBUG 0x00010000 /* enable debug messages */
#define SC_LOG_INPKT 0x00020000 /* log contents of good pkts recvd */
#define SC_LOG_OUTPKT 0x00040000 /* log contents of pkts sent */
#define SC_LOG_RAWIN 0x00080000 /* log all chars received */
#define SC_LOG_FLUSH 0x00100000 /* log all chars flushed */
#define SC_RCV_B7_0 0x01000000 /* have rcvd char with bit 7 = 0 */
#define SC_RCV_B7_1 0x02000000 /* have rcvd char with bit 7 = 1 */
#define SC_RCV_EVNP 0x04000000 /* have rcvd char with even parity */
#define SC_RCV_ODDP 0x08000000 /* have rcvd char with odd parity */
#define SC_MASK 0x0fff00ff /* bits that user can change */
/*
* State bits in sc_flags, not changeable by user.
*/
#define SC_TIMEOUT 0x00000400 /* timeout is currently pending */
#define SC_VJ_RESET 0x00000800 /* need to reset VJ decomp */
#define SC_COMP_RUN 0x00001000 /* compressor has been initiated */
#define SC_DECOMP_RUN 0x00002000 /* decompressor has been initiated */
#define SC_DC_ERROR 0x00004000 /* non-fatal decomp error detected */
#define SC_DC_FERROR 0x00008000 /* fatal decomp error detected */
#define SC_TBUSY 0x10000000 /* xmitter doesn't need a packet yet */
#define SC_PKTLOST 0x20000000 /* have lost or dropped a packet */
#define SC_FLUSH 0x40000000 /* flush input until next PPP_FLAG */
#define SC_ESCAPED 0x80000000 /* saw a PPP_ESCAPE */
/************************/
/*** LOCAL DATA TYPES ***/
/************************/
/*
* PPP interface control block.
*/
typedef struct PPPControl_s {
char ifname[IFNAMSIZ]; /* Interface name */
char openFlag; /* True when in use. */
char oldFrame; /* Old framing character for fd. */
int fd; /* File device ID of port. */
int kill_link; /* Shut the link down. */
int if_up; /* True when the interface is up. */
int errCode; /* Code indicating why interface is down. */
#ifndef ISS_OS
char pppStack[STACK_SIZE]; /* The ppp task stack. */
#endif
NBuf *inHead, *inTail; /* The input packet. */
PPPDevStates inState; /* The input process state. */
char inEscaped; /* Escape next character. */
u_int inProtocol; /* The input protocol code. */
u_int inFCS; /* Input Frame Check Sequence value. */
u_int inLen; /* Input packet length. */
int mtu; /* Peer's mru */
int pcomp; /* Does peer accept protocol compression? */
int accomp; /* Does peer accept addr/ctl compression? */
u_long lastXMit; /* Time of last transmission. */
ext_accm inACCM; /* Async-Ctl-Char-Map for input. */
ext_accm outACCM; /* Async-Ctl-Char-Map for output. */
#if VJ_SUPPORT > 0
int vjEnabled; /* Flag indicating VJ compression enabled. */
struct vjcompress vjComp; /* Van Jabobsen compression header. */
#endif
int traceOffset; /* Trace level offset. */
} PPPControl;
/*
* Ioctl definitions.
*/
struct npioctl {
int protocol; /* PPP procotol, e.g. PPP_IP */
enum NPmode mode;
};
/***********************************/
/*** LOCAL FUNCTION DECLARATIONS ***/
/***********************************/
static void pppMain(void *pd);
static void pppDispatch(int pd, NBuf *nb, u_int protocol);
static void pppDrop(PPPControl *pc);
static void pppInProc(int pd, u_char *s, int l);
static NBuf *pppMPutC(u_char c, ext_accm *outACCM, NBuf *nb);
static NBuf *pppMPutRaw(u_char c, NBuf *nb);
#define ESCAPE_P(accm, c) ((accm)[(c) >> 3] & pppACCMMask[c & 0x07])
/* For development use only. */
/******************************/
/*** PUBLIC DATA STRUCTURES ***/
/******************************/
int auth_required = 0; /* Peer is required to authenticate */
PPPControl pppControl[NUM_PPP]; /* The PPP interface control blocks. */
#if STATS_SUPPORT > 0
PPPStats pppStats; /* Statistics. */
#endif
/*
* PPP Data Link Layer "protocol" table.
* One entry per supported protocol.
* The last entry must be NULL.
*/
struct protent *protocols[] = {
&lcp_protent,
#if PAP_SUPPORT > 0
&pap_protent,
#endif
#if CHAP_SUPPORT > 0
&chap_protent,
#endif
#if CBCP_SUPPORT > 0
&cbcp_protent,
#endif
&ipcp_protent,
#if CCP_SUPPORT > 0
&ccp_protent,
#endif
NULL
};
/*
* Buffers for outgoing packets. This must be accessed only from the appropriate
* PPP task so that it doesn't need to be protected to avoid collisions.
*/
u_char outpacket_buf[NUM_PPP][PPP_MRU+PPP_HDRLEN];
/*****************************/
/*** LOCAL DATA STRUCTURES ***/
/*****************************/
/*
* FCS lookup table as calculated by genfcstab.
*/
const u_short fcstab[256] = {
0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
};
/* PPP's Asynchronous-Control-Character-Map. The mask array is used
* to select the specific bit for a character. */
static u_char pppACCMMask[] = {
0x01,
0x02,
0x04,
0x08,
0x10,
0x20,
0x40,
0x80
};
/***********************************/
/*** PUBLIC FUNCTION DEFINITIONS ***/
/***********************************/
/* Initialize the PPP subsystem. */
/*
void pppInit(Interface* pInterface)
{
}
*/
void pppInit(void)
{
struct protent *protp;
int i, j;
for (i = 0; i < NUM_PPP; i++) {
pppControl[i].openFlag = 0;
sprintf(pppControl[i].ifname, "ppp%d", i);
/*
* Initialize to the standard option set.
*/
for (j = 0; (protp = protocols[j]) != NULL; ++j)
(*protp->init)(i);
}
#if STATS_SUPPORT > 0
/* Clear the statistics. */
memset(&pppStats, 0, sizeof(pppStats));
pppStats.headLine.fmtStr = "\t\tPPP STATISTICS\r\n";
pppStats.ppp_ibytes.fmtStr = "\tBYTES IN : %5lu\r\n";
pppStats.ppp_ipackets.fmtStr = "\tPACKETS IN : %5lu\r\n";
pppStats.ppp_ierrors.fmtStr = "\tIN ERRORS : %5lu\r\n";
pppStats.ppp_derrors.fmtStr = "\tDISPATCH ERR: %5lu\r\n";
pppStats.ppp_obytes.fmtStr = "\tBYTES OUT : %5lu\r\n";
pppStats.ppp_opackets.fmtStr = "\tPACKETS OUT : %5lu\r\n";
pppStats.ppp_oerrors.fmtStr = "\tOUT ERRORS : %5lu\r\n";
#endif
}
/* Open a new PPP connection using the given I/O device.
* This initializes the PPP control block but does not
* attempt to negotiate the LCP session. If this port
* connects to a modem, the modem connection must be
* established before calling this.
* Return a new PPP connection descriptor on success or
* an error code (negative) on failure. */
int pppOpen(int fd)
{
PPPControl *pc;
char c;
int pd;
/* XXX
* Ensure that fd is not already used for PPP
*/
/* Find a free PPP session descriptor. */
OS_ENTER_CRITICAL();
for (pd = 0; pd < NUM_PPP && pppControl[pd].openFlag != 0; pd++);
if (pd >= NUM_PPP)
pd = PPPERR_OPEN;
else
pppControl[pd].openFlag = !0;
OS_EXIT_CRITICAL();
/*
* Save the old line discipline of fd, and set it to PPP.
* (For the Accu-Vote, save and set the framing character).
* Set the user name and password in case we need PAP
* authentication.
*/
if (pd >= 0) {
c = PPP_FLAG;
#ifdef OS_DEPENDENT
if (ioctl(fd, GETFRAME, &pppControl[pd].oldFrame) < 0
|| ioctl(fd, SETFRAME, &c) < 0) {
pd = PPPERR_DEVICE;
pppControl[pd].openFlag = 0;
}
#else
pppControl[pd].openFlag = 1;
#endif
upap_setloginpasswd(pd, user, passwd);
}
/* Launch a deamon thread. */
if (pd >= 0) {
lcp_init(pd);
pc = &pppControl[pd];
pc->fd = fd;
pc->kill_link = 0;
pc->if_up = 0;
pc->errCode = 0;
pc->inState = PDIDLE;
pc->inHead = NULL;
pc->inTail = NULL;
pc->inEscaped = 0;
pc->lastXMit = mtime() - MAXIDLEFLAG;
pc->traceOffset = 0;
#if VJ_SUPPORT > 0
pc->vjEnabled = 0;
vj_compress_init(&pc->vjComp);
#endif
/*
* Default the in and out accm so that escape and flag characters
* are always escaped.
*/
memset(pc->inACCM, 0, sizeof(ext_accm));
pc->inACCM[15] = 0x60;
memset(pc->outACCM, 0, sizeof(ext_accm));
pc->outACCM[15] = 0x60;
//#ifdef OS_DEPENDENT
OSTaskCreate(pppMain, (void*)pd, pc->pppStack + STACK_SIZE, (UBYTE)(PRI_PPP0 + pd));
//#endif
while(pd >= 0 && !pc->if_up) {
msleep(500);
if (lcp_phase[pd] == PHASE_DEAD) {
pppClose(pd);
if (pc->errCode)
pd = pc->errCode;
else
pd = PPPERR_CONNECT;
}
// else if (buttonStatus() == YESNOBUTTON) {
// pppClose(pd);
// pd = PPPERR_USER;
// }
}
pc->traceOffset = 2;
}
return pd;
}
/* Close a PPP connection and release the descriptor.
* Any outstanding packets in the queues are dropped.
* Return 0 on success, an error code on failure. */
int pppClose(int pd)
{
PPPControl *pc = &pppControl[pd];
int st = 0;
/* Disconnect */
pc->kill_link = !0;
pc->traceOffset = 0;
while(st >= 0 && lcp_phase[pd] != PHASE_DEAD) {
msleep(500);
// if (buttonStatus() == YESNOBUTTON)
// st = PPPERR_USER;
break;
}
#ifdef OS_DEPENDENT
/* Reset fd line discipline. In our case, the framing character. */
if (ioctl(pc->fd, SETFRAME, &pppControl[pd].oldFrame) < 0)
st = PPPERR_DEVICE;
#endif
pc->openFlag = 0;
return st;
}
/* Send a packet on the given connection.
* Return 0 on success, an error code on failure. */
#pragma argsused
int pppOutput(int pd, u_short protocol, NBuf *nb)
{
PPPControl *pc = &pppControl[pd];
u_int fcsOut = PPP_INITFCS;
NBuf *headMB = NULL, *tailMB = NULL, *tnb;
int st = 0;
u_char c = 0;
int n;
u_char *sPtr;
/* Grab an output buffer. */
nGET(headMB);
if (headMB == NULL) {
st = PPPERR_ALLOC;
PPPDEBUG((LOG_WARNING, TL_PPP, "pppOutput[%d]: first alloc fail", pd));
#if STATS_SUPPORT > 0
pppStats.PPPoerrors++;
#endif
/* Validate parameters. */
/* We let any protocol value go through - it can't hurt us
* and the peer will just drop it if it's not accepting it. */
} else if (pd < 0 || pd >= NUM_PPP || !pc->openFlag || !nb) {
st = PPPERR_PARAM;
PPPDEBUG((LOG_WARNING, TL_PPP, "pppOutput[%d]: bad parms prot=%d nb=%P",
pd, protocol, nb));
#if STATS_SUPPORT > 0
pppStats.PPPoerrors++;
#endif
/* Check that the link is up. */
} else if (lcp_phase[pd] == PHASE_DEAD) {
PPPDEBUG((LOG_ERR, TL_PPP, "pppOutput[%d]: link not up", pd));
#if STATS_SUPPORT > 0
pppStats.PPPderrors++;
#endif
st = PPPERR_OPEN;
} else {
#if VJ_SUPPORT > 0
/*
* Attempt Van Jacobson header compression if VJ is configured and
* this is an IP packet.
*/
if (protocol == PPP_IP && pc->vjEnabled) {
switch (vj_compress_tcp(&pc->vjComp, nb)) {
case TYPE_IP:
/* No change...
protocol = PPP_IP_PROTOCOL;
*/
break;
case TYPE_COMPRESSED_TCP:
protocol = PPP_VJC_COMP;
break;
case TYPE_UNCOMPRESSED_TCP:
protocol = PPP_VJC_UNCOMP;
break;
default:
PPPDEBUG((LOG_WARNING, TL_PPP, "pppOutput[%d]: bad IP packet", pd));
#if STATS_SUPPORT > 0
pppStats.PPPderrors++;
#endif
return PPPERR_PROTOCOL;
}
}
#endif
headMB->len = 0;
tailMB = headMB;
/* Build the PPP header. */
if (diffTime(pc->lastXMit) <= MAXIDLEFLAG)
tailMB = pppMPutRaw(PPP_FLAG, tailMB);
if (!pc->accomp) {
fcsOut = PPP_FCS(fcsOut, PPP_ALLSTATIONS);
tailMB = pppMPutC(PPP_ALLSTATIONS, &pc->outACCM, tailMB);
fcsOut = PPP_FCS(fcsOut, PPP_UI);
tailMB = pppMPutC(PPP_UI, &pc->outACCM, tailMB);
}
if (!pc->pcomp || protocol > 0xFF) {
c = (protocol >> 8) & 0xFF;
fcsOut = PPP_FCS(fcsOut, c);
tailMB = pppMPutC(c, &pc->outACCM, tailMB);
}
c = protocol & 0xFF;
fcsOut = PPP_FCS(fcsOut, c);
tailMB = pppMPutC(c, &pc->outACCM, tailMB);
/* Load packet. */
while (nb) {
sPtr = nBUFTOPTR(nb, u_char *);
n = nb->len;
while (n-- > 0) {
c = *sPtr++;
/* Update FCS before checking for special characters. */
fcsOut = PPP_FCS(fcsOut, c);
/* Copy to output buffer escaping special characters. */
tailMB = pppMPutC(c, &pc->outACCM, tailMB);
}
nFREE(nb, tnb);
nb = tnb;
}
/* Add FCS and trailing flag. */
c = ~fcsOut & 0xFF;
tailMB = pppMPutC(c, &pc->outACCM, tailMB);
c = (~fcsOut >> 8) & 0xFF;
tailMB = pppMPutC(c, &pc->outACCM, tailMB);
tailMB = pppMPutRaw(PPP_FLAG, tailMB);
/* If we failed to complete the packet, throw it away.
* Otherwise send it. */
if (!tailMB) {
st = PPPERR_ALLOC;
PPPDEBUG((pppControl[pd].traceOffset + LOG_WARNING, TL_PPP,
"pppOutput[%d]: Alloc err - dropping proto=%d",
pd, protocol));
nFreeChain(headMB);
#if STATS_SUPPORT > 0
pppStats.PPPoerrors++;
#endif
}
else {
PPPDEBUG((pppControl[pd].traceOffset + LOG_INFO, TL_PPP,
// "pppOutput[%d]: proto=x%X %d:%.*H", pd, protocol, headMB->chainLen, MIN(headMB->len * 2, 50), headMB->data));
"pppOutput[%d]: proto=x%X len=%d", pd, protocol, headMB->chainLen));
nPut(pc->fd, headMB);
#if STATS_SUPPORT > 0
pppStats.PPPopackets++;
#endif
}
headMB = NULL;
}
/* If we didn't consume the source buffer, drop it. */
if (nb)
nFreeChain(nb);
/* If we didn't send the output buffer, drop it. */
if (headMB) {
nFreeChain(headMB);
#if STATS_SUPPORT > 0
pppStats.PPPoerrors++;
#endif
}
return st;
}
/* Process an nBuf chain received on given connection.
* The nBuf chain is always passed on or freed making the original
* nBuf pointer invalid. Note that this does not check for packet
* chains. This does not require complete packets but if a packet
* spans calls, those calls must be in the correct order. This is
* designed to handle packets received from the serial interface
* but could be used for a loopback interface.
* Return 0 on success, an error code on failure.
*/
int pppInput(int pd, NBuf *nb)
{
NBuf *nextNBuf;
while (nb != NULL) {
/* Consume the buffer. Ideally we could just work on the
* recieved buffer but unless we get the serial driver to
* preprocess the escape sequences, it's easier to just
* work from one buffer to another. */
pppInProc(pd, nb->data, nb->len);
nFREE(nb, nextNBuf);
nb = nextNBuf;
}
return 0;
}
/* Get and set parameters for the given connection.
* Return 0 on success, an error code on failure. */
int pppIOCtl(int pd, int cmd, void *arg)
{
PPPControl *pc = &pppControl[pd];
int st = 0;
if (pd < 0 || pd >= NUM_PPP)
st = PPPERR_PARAM;
else {
switch(cmd) {
case PPPCTLG_UPSTATUS: /* Get the PPP up status. */
if (arg)
*(int *)arg = (int)(pc->if_up);
else
st = PPPERR_PARAM;
break;
case PPPCTLS_ERRCODE: /* Set the PPP error code. */
if (arg)
pc->errCode = *(int *)arg;
else
st = PPPERR_PARAM;
break;
case PPPCTLG_ERRCODE: /* Get the PPP error code. */
if (arg)
*(int *)arg = (int)(pc->errCode);
else
st = PPPERR_PARAM;
break;
case PPPCTLG_FD:
if (arg)
*(int *)arg = (int)(pc->fd);
else
st = PPPERR_PARAM;
break;
default:
st = PPPERR_PARAM;
break;
}
}
return st;
}
/*
* Return the Maximum Transmission Unit for the given PPP connection.
*/
u_int pppMTU(int pd)
{
PPPControl *pc = &pppControl[pd];
u_int st;
/* Validate parameters. */
if (pd < 0 || pd >= NUM_PPP || !pc->openFlag)
st = 0;
else
st = pc->mtu;
return st;
}
/*
* Write n characters to a ppp link.
* RETURN: >= 0 Number of characters written
* -1 Failed to write to device
*/
int pppWrite(int pd, const char *s, int n)
{
PPPControl *pc = &pppControl[pd];
short st = 0;
u_char c;
u_int fcsOut = PPP_INITFCS;
NBuf *headMB = NULL, *tailMB;
nGET(headMB);
if (headMB == NULL) {
st = PPPERR_ALLOC;
#if STATS_SUPPORT > 0
pppStats.PPPoerrors++;
#endif
} else {
headMB->len = 0;
tailMB = headMB;
/* If the link has been idle, we'll send a fresh flag character to
* flush any noise. */
if (diffTime(pc->lastXMit) <= MAXIDLEFLAG)
tailMB = pppMPutRaw(PPP_FLAG, tailMB);
pc->lastXMit = mtime();
/* Load output buffer. */
while (n-- > 0) {
c = *s++;
/* Update FCS before checking for special characters. */
fcsOut = PPP_FCS(fcsOut, c);
/* Copy to output buffer escaping special characters. */
tailMB = pppMPutC(c, &pc->outACCM, tailMB);
}
/* Add FCS and trailing flag. */
c = ~fcsOut & 0xFF;
tailMB = pppMPutC(c, &pc->outACCM, tailMB);
c = (~fcsOut >> 8) & 0xFF;
tailMB = pppMPutC(c, &pc->outACCM, tailMB);
tailMB = pppMPutRaw(PPP_FLAG, tailMB);
/* If we failed to complete the packet, throw it away.
* Otherwise send it. */
if (tailMB) {
PPPDEBUG((pppControl[pd].traceOffset + LOG_INFO, TL_PPP,
// "pppWrite[%d]: %d:%.*H", pd, headMB->len, MIN(headMB->len * 2, 40), headMB->data));
"pppWrite[%d]: len=%d", pd, headMB->len));
nPut(pc->fd, headMB);
#if STATS_SUPPORT > 0
pppStats.PPPopackets++;
#endif
}
else {
PPPDEBUG((pppControl[pd].traceOffset + LOG_WARNING, TL_PPP,
// "pppWrite[%d]: Alloc err - dropping %d:%.*H", pd, headMB->len, MIN(headMB->len * 2, 40), headMB->data));
"pppWrite[%d]: Alloc err - dropping nBuf len=%d", pd, headMB->len));
nFreeChain(headMB);
#if STATS_SUPPORT > 0
pppStats.PPPoerrors++;
#endif
}
}
return st;
}
/*
* ppp_send_config - configure the transmit characteristics of
* the ppp interface.
*/
void ppp_send_config(
int unit,
int mtu,
u_int32_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, TL_PPP, "ppp_send_config[%d]: outACCM=%X %X %X %X",
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, TL_PPP, "ppp_set_xaccm[%d]: outACCM=%X %X %X %X",
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.
*/
#pragma argsused /* XXX */
void ppp_recv_config(
int unit,
int mru,
u_int32_t asyncmap,
int pcomp,
int accomp
)
{
PPPControl *pc = &pppControl[unit];
int i;
/* 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, TL_PPP, "ppp_recv_config[%d]: inACCM=%X %X %X %X",
unit,
pc->inACCM[0], pc->inACCM[1], pc->inACCM[2], pc->inACCM[3]));
}
/*
* 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.
*/
#pragma argsused
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.
*/
#pragma argsused
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.
*/
#pragma argsused
int ccp_fatal_error(int unit)
{
/* XXX */
return 0;
}
/*
* get_idle_time - return how long the link has been idle.
*/
#pragma argsused
int get_idle_time(int u, struct ppp_idle *ip)
{
/* XXX */
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.
*/
u_int32_t GetMask(u_int32_t addr)
{
u_int32_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 = netMask | 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
*/
#pragma argsused
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, TL_PPP, "sifvjcomp: VJ compress enable=%d slot=%d max slot=%d",
vjcomp, cidcomp, maxcid));
#endif
return 0;
}
/*
* sifup - Config the interface up and enable IP packets to pass.
*/
#pragma argsused
int sifup(int pd)
{
PPPControl *pc = &pppControl[pd];
int st = 1;
if (pd < 0 || pd >= NUM_PPP || !pc->openFlag) {
st = 0;
PPPDEBUG((LOG_WARNING, TL_PPP, "sifup[%d]: bad parms", pd));
} else {
pc->if_up = 1;
pc->errCode = 0;
}
return st;
}
/*
* sifnpmode - Set the mode for handling packets for a given NP.
*/
#pragma argsused
int sifnpmode(int u, int proto, enum NPmode mode)
{
return 0;
}
/*
* sifdown - Config the interface down and disable IP.
*/
#pragma argsused
int sifdown(int pd)
{
PPPControl *pc = &pppControl[pd];
int st = 1;
if (pd < 0 || pd >= NUM_PPP || !pc->openFlag) {
st = 0;
PPPDEBUG((LOG_WARNING, TL_PPP, "sifdown[%d]: bad parms", pd));
} else
pc->if_up = 0;
return st;
}
/*
* sifaddr - Config the interface IP addresses and netmask.
*/
#pragma argsused
int sifaddr(
int u, /* Interface unit ??? */
u_int32_t o, /* Our IP address ??? */
u_int32_t h, /* IP subnet mask ??? */
u_int32_t m /* IP broadcast address ??? */
)
{
return 1;
}
/*
* cifaddr - Clear the interface IP addresses, and delete routes
* through the interface if possible.
*/
#pragma argsused
int cifaddr(
int u, /* Interface unit ??? */
u_int32_t o, /* Our IP address ??? */
u_int32_t h /* IP broadcast address ??? */
)
{
return 1;
}
/*
* sifdefaultroute - assign a default route through the address given.
*/
#pragma argsused
int sifdefaultroute(int u, u_int32_t l, u_int32_t g)
{
ipSetDefault(l, g, IFT_PPP, u);
return !0;
}
/*
* cifdefaultroute - delete a default route through the address given.
*/
#pragma argsused
int cifdefaultroute(int u, u_int32_t l, u_int32_t g)
{
ipClearDefault();
return !0;
}
/**********************************/
/*** 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 *pd)
{
PPPControl* pc = &pppControl[(int)pd];
NBuf* curNBuf = NULL;
/*
* Start the connection and handle incoming events (packet or timeout).
*/
// trace(LOG_NOTICE, "Connecting %s <--> %s", pc->ifname, nameForDevice(pc->fd));
lcp_lowerup((int)pd);
lcp_open((int)pd); /* Start protocol */
while (lcp_phase[(int)pd] != PHASE_DEAD) {
if (pc->kill_link) {
/* This will leave us at PHASE_DEAD. */
lcp_close(0, "User request");
pc->kill_link = 0;
}
else {
nGet(pc->fd, &curNBuf, MAXKILLDELAY);
avRandomize();
if (curNBuf != NULL) {
pppInput((int)pd, curNBuf);
/* curNBuf is invalid now so we don't need to free it. */
}
pc->if_up = 1; // for debugging only
}
}
#ifdef OS_DEPENDENT
OSTaskDel(OS_PRIO_SELF);
#endif
}
/*
* Pass the processed input packet to the appropriate handler.
*/
static void pppDispatch(int pd, NBuf *nb, u_int protocol)
{
if (nb != NULL) {
switch(protocol) {
case PPP_LCP: /* Link Control Protocol */
PPPDEBUG((pppControl[pd].traceOffset + LOG_INFO, TL_PPP,
// "pppDispatch[%d]: lcp in %d:%.*H", pd, nb->len, MIN(nb->len * 2, 40), nb->data));
"pppDispatch[%d]: lcp in nBuf len=%d", pd, nb->len));
/* XXX Assume that LCP packet fits in single nBuf. */
lcp_protent.input(pd, nb->data, nb->len);
nFreeChain(nb);
break;
case PPP_IPCP: /* IP Control Protocol */
PPPDEBUG((pppControl[pd].traceOffset + LOG_INFO, TL_PPP,
// "pppDispatch[%d]: ipcp in %d:%.*H", pd, nb->len, MIN(nb->len * 2, 40), nb->data));
"pppDispatch[%d]: ipcp in nBuf len=%d", pd, nb->len));
/* XXX Assume that IPCP packet fits in single nBuf. */
ipcp_protent.input(pd, nb->data, nb->len);
nFreeChain(nb);
break;
case PPP_PAP: /* Password Authentication Protocol */
PPPDEBUG((pppControl[pd].traceOffset + LOG_INFO, TL_PPP,
// "pppDispatch[%d]: pap in %d:%.*H", pd, nb->len, MIN(nb->len * 2, 40), nb->data));
"pppDispatch[%d]: pap in nBuf len=%d", pd, nb->len));
pap_protent.input(pd, nb->data, nb->len);
nFreeChain(nb);
break;
case PPP_VJC_COMP: /* VJ compressed TCP */
#if VJ_SUPPORT > 0
PPPDEBUG((pppControl[pd].traceOffset + LOG_INFO, TL_PPP,
// "pppDispatch[%d]: vj_comp in %d:%.*H", pd, nb->len, MIN(nb->len * 2, 40), nb->data));
"pppDispatch[%d]: vj_comp in nBuf len=%d", pd, nb->len));
/*
* Clip off the VJ header and prepend the rebuilt TCP/IP header and
* pass the result to IP.
*/
if (vj_uncompress_tcp(&nb, &pppControl[pd].vjComp) >= 0) {
ipInput(nb, IFT_PPP, pd);
} else {
/* Something's wrong so drop it. */
PPPDEBUG((pppControl[pd].traceOffset + LOG_WARNING, TL_PPP,
"pppDispatch[%d]: Dropping VJ compressed", pd));
nFreeChain(nb);
}
#else
/* No handler for this protocol so drop the packet. */
PPPDEBUG((pppControl[pd].traceOffset + LOG_INFO, TL_PPP,
// "pppDispatch[%d]: drop VJ Comp in %d:.*H", pd, nb->len, MIN(nb->len * 2, 40), nb->data));
"pppDispatch[%d]: drop VJ Comp in %d:%s", pd, nb->len, nb->data));
nFreeChain(nb);
#if STATS_SUPPORT > 0
pppStats.PPPderrors++;
#endif
#endif
break;
case PPP_VJC_UNCOMP: /* VJ uncompressed TCP */
#if VJ_SUPPORT > 0
PPPDEBUG((pppControl[pd].traceOffset + LOG_INFO, TL_PPP,
// "pppDispatch[%d]: vj_un in %d:%.*H", pd, nb->len, MIN(nb->len * 2, 40), nb->data));
"pppDispatch[%d]: vj_un in nBuf len=%d", pd, nb->len));
/*
* Process the TCP/IP header for VJ header compression and then pass
* the packet to IP.
*/
if (vj_uncompress_uncomp(nb, &pppControl[pd].vjComp) >= 0) {
ipInput(nb, IFT_PPP, pd);
} else {
/* Something's wrong so drop it. */
PPPDEBUG((pppControl[pd].traceOffset + LOG_WARNING, TL_PPP,
"pppDispatch[%d]: Dropping VJ uncompressed", pd));
nFreeChain(nb);
}
#else
/* No handler for this protocol so drop the packet. */
PPPDEBUG((pppControl[pd].traceOffset + LOG_INFO, TL_PPP,
"pppDispatch[%d]: drop VJ UnComp in %d:.*H",
pd, nb->len, MIN(nb->len * 2, 40), nb->data));
nFreeChain(nb);
#if STATS_SUPPORT > 0
pppStats.PPPderrors++;
#endif
#endif
break;
case PPP_IP: /* Internet Protocol */
PPPDEBUG((pppControl[pd].traceOffset + LOG_INFO, TL_PPP,
// "pppDispatch[%d]: ip in %d:%.*H", pd, nb->len, MIN(nb->len * 2, 40), nb->data));
"pppDispatch[%d]: ip in nBuf len=%d", pd, nb->len));
ipInput(nb, IFT_PPP, pd);
break;
case PPP_AT: /* AppleTalk Protocol */
case PPP_COMP: /* compressed packet */
case PPP_ATCP: /* AppleTalk Control Protocol */
case PPP_CCP: /* Compression Control Protocol */
case PPP_LQR: /* Link Quality Report protocol */
case PPP_CHAP: /* Cryptographic Handshake Auth. Protocol */
case PPP_CBCP: /* Callback Control Protocol */
default:
/* No handler for this protocol so drop the packet. */
PPPDEBUG((pppControl[pd].traceOffset + LOG_INFO, TL_PPP,
// "pppDispatch[%d]: drop 0x%X in %d:%.*H", pd, protocol, nb->len, MIN(nb->len * 2, 40), nb->data));
"pppDispatch[%d]: drop 0x%X in nBuf len=%d", pd, protocol, nb->len));
nFreeChain(nb);
#if STATS_SUPPORT > 0
pppStats.PPPderrors++;
#endif
break;
}
}
}
/*
* Drop the input packet.
*/
static void pppDrop(PPPControl *pc)
{
if (pc->inHead != NULL) {
// PPPDEBUG((LOG_INFO, TL_PPP, "pppDrop: %d:%.*H", pc->inHead->len, min(60, pc->inHead->len * 2), pc->inHead->data));
PPPDEBUG((LOG_INFO, TL_PPP, "pppDrop: nBuf len=%d", pc->inHead->len));
nFreeChain(pc->inHead);
pc->inHead = NULL;
pc->inTail = NULL;
}
#if VJ_SUPPORT > 0
vj_uncompress_err(&pc->vjComp);
#endif
}
/*
* Process a received octet string.
*/
static void pppInProc(int pd, u_char *s, int l)
{
PPPControl *pc = &pppControl[pd];
NBuf *nextNBuf;
u_char curChar;
while (l-- > 0) {
curChar = *s++;
/* Handle special characters. */
if (ESCAPE_P(pc->inACCM, curChar)) {
/* Check for escape sequences. */
/* XXX Note that this does not handle an escaped 0x5d character which
* would appear as an escape character. Since this is an ASCII ']'
* and there is no reason that I know of to escape it, I won't complicate
* the code to handle this case. GLL */
if (curChar == PPPESCAPE)
pc->inEscaped = !0;
/* Check for the flag character. */
else if (curChar == PPPFLAG) {
/* If this is just an extra flag character, ignore it. */
if (pc->inState == PDADDRESS)
;
/* If we haven't received the packet header, drop what has come in. */
else if (pc->inState < PDDATA) {
PPPDEBUG((pc->traceOffset + LOG_WARNING, TL_PPP,
"pppInProc[%d]: Dropping incomplete packet %d",
pd, pc->inState));
pppDrop(pc);
}
/* If the fcs is invalid, drop the packet. */
else if (pc->inFCS != PPP_GOODFCS) {
PPPDEBUG((pc->traceOffset + LOG_INFO, TL_PPP,
"pppInProc[%d]: Dropping bad fcs 0x%X proto=x%X",
pd, pc->inFCS, pc->inProtocol));
pppDrop(pc);
#if STATS_SUPPORT > 0
pppStats.PPPierrors++;
#endif
}
/* Otherwise it's a good packet so pass it on. */
else {
/* Trim off the checksum. */
pc->inTail->len -= 2;
pc->inLen -= 2;
/* Update the packet header. */
pc->inHead->chainLen = pc->inLen;
/* Dispatch the packet thereby consuming it. */
pppDispatch(pd, pc->inHead, pc->inProtocol);
pc->inHead = NULL;
pc->inTail = NULL;
#if STATS_SUPPORT > 0
pppStats.PPPipackets++;
#endif
}
/* Prepare for a new packet. */
pc->inFCS = PPP_INITFCS;
pc->inState = PDADDRESS;
pc->inEscaped = 0;
}
/* Other characters are usually control characters that may have
* been inserted by the physical layer so here we just drop them. */
else {
PPPDEBUG((pc->traceOffset + LOG_WARNING, TL_PPP,
"pppInProc[%d]: Dropping ACCM char <%d>", pd, curChar));
}
}
/* Process other characters. */
else {
/* Unencode escaped characters. */
if (pc->inEscaped) {
pc->inEscaped = 0;
curChar ^= PPPESCMASK;
}
/* Having removed transparency encoding and physical layer control characters,
* we can update the frame check sequence nunber. */
pc->inFCS = PPP_FCS(pc->inFCS, curChar);
/* Process character relative to current state. */
switch(pc->inState) {
case PDIDLE: /* Idle state - waiting. */
/* Drop the character. */
break;
case PDSTART: /* Process start flag. */
/* Drop the character - we would have processed a flag character
* above. */
break;
case PDCONTROL: /* Process control field. */
/* If we don't get a valid control code, restart. */
if (curChar == PPPCONTROL) {
pc->inState = PDPROTOCOL1;
}
else {
PPPDEBUG((pc->traceOffset + LOG_WARNING, TL_PPP,
"pppInProc[%d]: Invalid control <%d>", pd, curChar));
pc->inState = PDSTART;
}
break;
case PDADDRESS: /* Process address field. */
if (curChar == PPPADDRESS) {
pc->inState = PDCONTROL;
break;
}
/* Else assume compressed address and control fields so
* fall through to get the protocol... */
case PDPROTOCOL1: /* Process protocol field 1. */
/* If the lower bit is set, this is the end of the protocol
* field. */
if (curChar & 1) {
pc->inProtocol = curChar;
pc->inState = PDDATA;
}
else {
pc->inProtocol = (u_int)curChar << 8;
pc->inState = PDPROTOCOL2;
}
break;
case PDPROTOCOL2: /* Process protocol field 2. */
pc->inProtocol |= curChar;
pc->inState = PDDATA;
break;
case PDDATA: /* Process data byte. */
/* Make space to receive processed data. */
if (pc->inTail == NULL || nTRAILINGSPACE(pc->inTail) <= 0) {
/* If we haven't started a packet, we need a packet header. */
nGET(nextNBuf);
if (nextNBuf == NULL) {
/* No free buffers. Drop the input packet and let the
* higher layers deal with it. Continue processing
* the received nBuf chain in case a new packet starts. */
PPPDEBUG((LOG_ERR, TL_PPP, "pppInProc[%d]: NO FREE MBUFS!", pd));
pppDrop(pc);
pc->inState = PDSTART; /* Wait for flag sequence. */
pc->inFCS = PPP_INITFCS;
} else {
*(nextNBuf->data) = curChar;
nextNBuf->len = 1;
nextNBuf->nextBuf = NULL;
if (pc->inHead == NULL) {
pc->inHead = nextNBuf;
pc->inLen = 1;
}
else { /* Since if inHead is not NULL, then neither is inTail! */
pc->inTail->nextBuf = nextNBuf;
pc->inLen++;
}
pc->inTail = nextNBuf;
}
}
/* Load character into buffer. */
else {
pc->inTail->data[pc->inTail->len++] = curChar;
pc->inLen++;
}
break;
}
}
}
}
/*
* pppMPutC - append given character to end of given nBuf. If the character
* needs to be escaped, do so. If nBuf is full, append another.
* Return the current nBuf.
*/
static NBuf *pppMPutC(u_char c, ext_accm *outACCM, NBuf *nb)
{
NBuf *tb = nb;
/* Make sure there is room for the character and an escape code.
* Sure we don't quite fill the buffer if the character doesn't
* get escaped but is one character worth complicating this? */
/* Note: We assume no packet header. */
if (nb && (&nb->body[NBUFSZ] - (nb->data + nb->len)) < 2) {
nGET(tb);
if (tb) {
nb->nextBuf = tb;
tb->len = 0;
}
nb = tb;
}
if (nb) {
if (ESCAPE_P(*outACCM, c)) {
*(nb->data + nb->len++) = PPP_ESCAPE;
*(nb->data + nb->len++) = c ^ PPP_TRANS;
}
else
*(nb->data + nb->len++) = c;
}
return tb;
}
/*
* pppMPutRaw - append given character to end of given nBuf without escaping
* it. If nBuf is full, append another.
* This is normally used to add the flag character to a packet.
* Return the current nBuf.
*/
static NBuf *pppMPutRaw(u_char c, NBuf *nb)
{
NBuf *tb = nb;
/* Make sure there is room for the character and an escape code.
* Sure we don't quite fill the buffer if the character doesn't
* get escaped but is one character worth complicating this? */
/* Note: We assume no packet header. */
if (nb && (&nb->body[NBUFSZ] - (nb->data + nb->len)) < 2) {
nGET(tb);
if (tb) {
nb->nextBuf = tb;
tb->len = 0;
}
nb = tb;
}
if (nb) {
*(nb->data + nb->len++) = c;
}
return tb;
}
