ppp.c

《嵌入式网络系统设计-基于Atmel ARM7 系列》这个本书的光盘资料

	    	PPPDEBUG((LOG_DEBUG, "pppMainWakeup: unit %d kill_link -> pppStopCB\n", pd));
		pc->errCode = PPPERR_USER;
		/* This will leave us at PHASE_DEAD. */
    		tcpip_callback(pppStopCB, arg);
		pc->kill_link = 0;
        }
        else if (pc->sig_hup) {
	    	PPPDEBUG((LOG_DEBUG, "pppMainWakeup: unit %d sig_hup -> pppHupCB\n", pd));
		pc->sig_hup = 0;
    		tcpip_callback(pppHupCB, arg);
        } else {
		int c = sio_read(pc->fd, p->payload, p->len);
		if(c > 0) {
			pppInProc(pd, p->payload, c);
		} else {
		    PPPDEBUG((LOG_DEBUG, "pppMainWakeup: unit %d sio_read len=%d returned %d\n", pd, p->len, c));
		    sys_msleep(1); /* give other tasks a chance to run */
		}
        }
    }
	PPPDEBUG((LOG_INFO, "pppMain: unit %d: PHASE_DEAD\n", pd));
    pbuf_free(p);

out:
	PPPDEBUG((LOG_DEBUG, "pppMain: unit %d: linkStatusCB=%lx errCode=%d\n", pd, pc->linkStatusCB, pc->errCode));
    if(pc->linkStatusCB)
	    pc->linkStatusCB(pc->linkStatusCtx, pc->errCode ? pc->errCode : PPPERR_PROTOCOL, NULL);

    pc->openFlag = 0;
}

static struct pbuf *pppSingleBuf(struct pbuf *p)
{
	struct pbuf *q, *b;
	u_char *pl;

	if(p->tot_len == p->len)
		return p;

	q = pbuf_alloc(PBUF_RAW, p->tot_len, PBUF_RAM);
	if(!q) {
		PPPDEBUG((LOG_ERR,
                        "pppSingleBuf: unable to alloc new buf (%d)\n", p->tot_len));
		return p; /* live dangerously */
	}

	for(b = p, pl = q->payload; b != NULL; b = b->next) {
		memcpy(pl, b->payload, b->len);
		pl += b->len;
	}

	pbuf_free(p);

	return q;
}

struct pppInputHeader {
	int unit;
	u16_t proto;
};

/*
 * Pass the processed input packet to the appropriate handler.
 * This function and all handlers run in the context of the tcpip_thread
 */
static void pppInput(void *arg)
{
	struct pbuf *nb = (struct pbuf *)arg;
    u16_t protocol;
    int pd;

	pd = ((struct pppInputHeader *)nb->payload)->unit;
	protocol = ((struct pppInputHeader *)nb->payload)->proto;

    pbuf_header(nb, -(int)sizeof(struct pppInputHeader));

#if LINK_STATS
    lwip_stats.link.recv++;
#endif /* LINK_STATS */

    /*
     * Toss all non-LCP packets unless LCP is OPEN.
     * Until we get past the authentication phase, toss all packets
     * except LCP, LQR and authentication packets.
     */
    if((lcp_phase[pd] <= PHASE_AUTHENTICATE) && (protocol != PPP_LCP)) {
	    if(!((protocol == PPP_LQR) || (protocol == PPP_PAP) || (protocol == PPP_CHAP)) ||
			(lcp_phase[pd] != PHASE_AUTHENTICATE)) {
		PPPDEBUG((LOG_INFO, "pppInput: discarding proto 0x%04X in phase %d\n", protocol, lcp_phase[pd]));
		goto drop;
	    }
    }

    switch(protocol) {
    case PPP_VJC_COMP:      /* VJ compressed TCP */
#if VJ_SUPPORT > 0
        PPPDEBUG((LOG_INFO, "pppInput[%d]: vj_comp in pbuf len=%d\n", 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) {
            if (pppControl[pd].netif.input != NULL) {
              pppControl[pd].netif.input(nb, &pppControl[pd].netif);
            }
			return;
        }
	/* Something's wrong so drop it. */
	PPPDEBUG((LOG_WARNING, "pppInput[%d]: Dropping VJ compressed\n", pd));
#else
        /* No handler for this protocol so drop the packet. */
        PPPDEBUG((LOG_INFO, "pppInput[%d]: drop VJ Comp in %d:%s\n", pd, nb->len, nb->payload));
#endif /* VJ_SUPPORT > 0 */
	break;
    case PPP_VJC_UNCOMP:    /* VJ uncompressed TCP */
#if VJ_SUPPORT > 0
        PPPDEBUG((LOG_INFO, "pppInput[%d]: vj_un in pbuf len=%d\n", 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) {
            if (pppControl[pd].netif.input != NULL) {
              pppControl[pd].netif.input(nb, &pppControl[pd].netif);
            }
			return;
        }
	/* Something's wrong so drop it. */
	PPPDEBUG((LOG_WARNING, "pppInput[%d]: Dropping VJ uncompressed\n", pd));
#else
        /* No handler for this protocol so drop the packet. */
        PPPDEBUG((LOG_INFO,
                    "pppInput[%d]: drop VJ UnComp in %d:.*H\n", 
                    pd, nb->len, LWIP_MIN(nb->len * 2, 40), nb->payload));
#endif /* VJ_SUPPORT > 0 */
	break;
    case PPP_IP:            /* Internet Protocol */
        PPPDEBUG((LOG_INFO, "pppInput[%d]: ip in pbuf len=%d\n", pd, nb->len));
        if (pppControl[pd].netif.input != NULL) {
          pppControl[pd].netif.input(nb, &pppControl[pd].netif);
        }
		return;
    default:
	{
		struct protent *protp;
		int i;

		/*
		 * Upcall the proper protocol input routine.
		 */
		for (i = 0; (protp = ppp_protocols[i]) != NULL; ++i) {
			if (protp->protocol == protocol && protp->enabled_flag) {
				PPPDEBUG((LOG_INFO, "pppInput[%d]: %s len=%d\n", pd, protp->name, nb->len));
				nb = pppSingleBuf(nb);
				(*protp->input)(pd, nb->payload, nb->len);
				goto out;
			}
		}

		/* No handler for this protocol so reject the packet. */
		PPPDEBUG((LOG_INFO, "pppInput[%d]: rejecting unsupported proto 0x%04X len=%d\n", pd, protocol, nb->len));
		pbuf_header(nb, sizeof(protocol));
#if BYTE_ORDER == LITTLE_ENDIAN
		protocol = htons(protocol);
		memcpy(nb->payload, &protocol, sizeof(protocol));
#endif
		lcp_sprotrej(pd, nb->payload, nb->len);
	}
	break;
    }

drop:
#if LINK_STATS
    lwip_stats.link.drop++;
#endif

out:
    pbuf_free(nb);
    return;
}


/*
 * Drop the input packet.
 */
static void pppDrop(PPPControl *pc)
{
    if (pc->inHead != NULL) {
#if 0	    
        PPPDEBUG((LOG_INFO, "pppDrop: %d:%.*H\n", pc->inHead->len, min(60, pc->inHead->len * 2), pc->inHead->payload));
#endif	
        PPPDEBUG((LOG_INFO, "pppDrop: pbuf len=%d\n", pc->inHead->len));
	if (pc->inTail && (pc->inTail != pc->inHead))
	    pbuf_free(pc->inTail);
        pbuf_free(pc->inHead);
        pc->inHead = NULL;
        pc->inTail = NULL;
    }
#if VJ_SUPPORT > 0
    vj_uncompress_err(&pc->vjComp);
#endif

#if LINK_STATS
    lwip_stats.link.drop++;
#endif /* LINK_STATS */
}


/*
 * Process a received octet string.
 */
static void pppInProc(int pd, u_char *s, int l)
{
    PPPControl *pc = &pppControl[pd];
    struct pbuf *nextNBuf;
    u_char curChar;

    PPPDEBUG((LOG_DEBUG, "pppInProc[%d]: got %d bytes\n", pd, l));
    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 == PPP_ESCAPE)
                pc->inEscaped = 1;
            /* Check for the flag character. */
            else if (curChar == PPP_FLAG) {
                /* 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((LOG_WARNING,
                                "pppInProc[%d]: Dropping incomplete packet %d\n", 
                                pd, pc->inState));
#if LINK_STATS
					lwip_stats.link.lenerr++;
#endif
                    pppDrop(pc);
                }
                /* If the fcs is invalid, drop the packet. */
                else if (pc->inFCS != PPP_GOODFCS) {
                    PPPDEBUG((LOG_INFO,
                                "pppInProc[%d]: Dropping bad fcs 0x%04X proto=0x%04X\n", 
                                pd, pc->inFCS, pc->inProtocol));
#if LINK_STATS
					lwip_stats.link.chkerr++;
#endif
                    pppDrop(pc);
                }
                /* Otherwise it's a good packet so pass it on. */
                else {
                    
                    /* Trim off the checksum. */
		    if(pc->inTail->len >= 2) {
			pc->inTail->len -= 2;

			pc->inTail->tot_len = pc->inTail->len;
			if (pc->inTail != pc->inHead) {
			    pbuf_cat(pc->inHead, pc->inTail);
			}
		    } else {
			pc->inTail->tot_len = pc->inTail->len;
			if (pc->inTail != pc->inHead) {
			    pbuf_cat(pc->inHead, pc->inTail);
			}

			pbuf_realloc(pc->inHead, pc->inHead->tot_len - 2);
		    }

                    /* Dispatch the packet thereby consuming it. */
		    if(tcpip_callback(pppInput, pc->inHead) != ERR_OK) {
                    	PPPDEBUG((LOG_ERR,
				    "pppInProc[%d]: tcpip_callback() failed, dropping packet\n", pd));
			pbuf_free(pc->inHead);
#if LINK_STATS
			lwip_stats.link.drop++;
#endif
		    }
                    pc->inHead = NULL;
                    pc->inTail = NULL;
                }
                    
                /* 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((LOG_WARNING,
                            "pppInProc[%d]: Dropping ACCM char <%d>\n", pd, curChar));
            }
        }
        /* Process other characters. */
        else {
            /* Unencode escaped characters. */
            if (pc->inEscaped) {
                pc->inEscaped = 0;
                curChar ^= PPP_TRANS;
            }
            
            /* Process character relative to current state. */
            switch(pc->inState) {
            case PDIDLE:                    /* Idle state - waiting. */
                /* Drop the character if it's not 0xff
                 * we would have processed a flag character above. */
                if (curChar != PPP_ALLSTATIONS) {
                	break;
				}

				/* Fall through */
            case PDSTART:                   /* Process start flag. */
                /* Prepare for a new packet. */
                pc->inFCS = PPP_INITFCS;

				/* Fall through */
            case PDADDRESS:                 /* Process address field. */
                if (curChar == PPP_ALLSTATIONS) {
                    pc->inState = PDCONTROL;
                    break;
                }
                /* Else assume compressed address and control fields so
                 * fall through to get the protocol... */
            case PDCONTROL:                 /* Process control field. */
                /* If we don't get a valid control code, restart. */
                if (curChar == PPP_UI) {
                    pc->inState = PDPROTOCOL1;
                	break;
                }
#if 0
                else {
                    PPPDEBUG((LOG_WARNING,
                                "pppInProc[%d]: Invalid control <%d>\n", pd, curChar));
                    pc->inState = PDSTART;
                }
#endif
            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 || pc->inTail->len == PBUF_POOL_BUFSIZE) {
		    if(pc->inTail) {
			pc->inTail->tot_len = pc->inTail->len;
			if (pc->inTail != pc->inHead) {
			    pbuf_cat(pc->inHead, pc->inTail);
			}
		    }
                    /* If we haven't started a packet, we need a packet header. */
                    nextNBuf = pbuf_alloc(PBUF_RAW, 0, PBUF_POOL);
                    if (nextNBuf == NULL) {
                        /* No free buffers.  Drop the input packet and let the
                         * higher layers deal with it.  Continue processing
                         * the received pbuf chain in case a new packet starts. */
                        PPPDEBUG((LOG_ERR, "pppInProc[%d]: NO FREE MBUFS!\n", pd));
#if LINK_STATS
						lwip_stats.link.memerr++;
#endif /* LINK_STATS */
                        pppDrop(pc);
                        pc->inState = PDSTART;  /* Wait for flag sequence. */
			break;
                    }
		    if (pc->inHead == NULL) {
			struct pppInputHeader *pih = nextNBuf->payload;

			pih->unit = pd;
			pih->proto = pc->inProtocol;

			nextNBuf->len += sizeof(*pih);

			pc->inHead = nextNBuf;
		    }
		    pc->inTail = nextNBuf;
                }
                /* Load character into buffer. */
                ((u_char*)pc->inTail->payload)[pc->inTail->len++] = curChar;
                break;
            }

            /* update the frame check sequence number. */
            pc->inFCS = PPP_FCS(pc->inFCS, curChar);
        }
    }
	avRandomize();
}

#endif /* PPP_SUPPORT */