--- ppp/pppd/demand.c

+++ ppp/pppd/demand.c	2000/06/28 14:54:04

@@ -25,6 +25,8 @@

 #include <errno.h>

 #include <fcntl.h>

 #include <netdb.h>

+#include <unistd.h>

+#include <syslog.h>

 #include <sys/param.h>

 #include <sys/types.h>

 #include <sys/wait.h>

@@ -32,6 +34,8 @@

 #include <sys/resource.h>

 #include <sys/stat.h>

 #include <sys/socket.h>

+#include <netinet/in.h>

+#include <arpa/inet.h>

 #ifdef PPP_FILTER

 #include <net/if.h>

 #include <net/bpf.h>

@@ -210,6 +214,14 @@

     int c, rv;

     rv = 0;

+

+/* check for synchronous connection... */

+

+    if ( (p[0] == 0xFF) && (p[1] == 0x03) ) {

+        rv = loop_frame(p,n);

+        return rv;

+    }

+

     for (; n > 0; --n) {

 	c = *p++;

 	if (c == PPP_FLAG) {

@@ -288,17 +300,102 @@

  * loopback, now that the real serial link is up.

  */

 void

-demand_rexmit(proto)

+demand_rexmit(proto, newip)

     int proto;

+    u_int32_t newip;

 {

     struct packet *pkt, *prev, *nextpkt;

+    unsigned short checksum;

+    unsigned short pkt_checksum = 0;

+    unsigned iphdr;

+    struct timeval tv;

+    char cv = 0;

+    char ipstr[16];

     prev = NULL;

     pkt = pend_q;

     pend_q = NULL;

+    tv.tv_sec = 1;

+    tv.tv_usec = 0;

+    select(0,NULL,NULL,NULL,&tv);	/* Sleep for 1 Seconds */

     for (; pkt != NULL; pkt = nextpkt) {

 	nextpkt = pkt->next;

 	if (PPP_PROTOCOL(pkt->data) == proto) {

+            if ( (proto == PPP_IP) && newip ) {

+		/* Get old checksum */

+

+		iphdr = (pkt->data[4] & 15) << 2;

+		checksum = *((unsigned short *) (pkt->data+14));

+                if (checksum == 0xFFFF) {

+                    checksum = 0;

+                }

+

+ 

+                if (pkt->data[13] == 17) {

+                    pkt_checksum =  *((unsigned short *) (pkt->data+10+iphdr));

+		    if (pkt_checksum) {

+                        cv = 1;

+                        if (pkt_checksum == 0xFFFF) {

+                            pkt_checksum = 0;

+                        }

+                    }

+                    else {

+                       cv = 0;

+                    }

+                }

+

+		if (pkt->data[13] == 6) {

+		    pkt_checksum = *((unsigned short *) (pkt->data+20+iphdr));

+		    cv = 1;

+                    if (pkt_checksum == 0xFFFF) {

+                        pkt_checksum = 0;

+                    }

+		}

+

+		/* Delete old Source-IP-Address */

+                checksum -= *((unsigned short *) (pkt->data+16)) ^ 0xFFFF;

+                checksum -= *((unsigned short *) (pkt->data+18)) ^ 0xFFFF;

+

+		pkt_checksum -= *((unsigned short *) (pkt->data+16)) ^ 0xFFFF;

+		pkt_checksum -= *((unsigned short *) (pkt->data+18)) ^ 0xFFFF;

+

+		/* Change Source-IP-Address */

+                * ((u_int32_t *) (pkt->data + 16)) = newip;

+

+		/* Add new Source-IP-Address */

+                checksum += *((unsigned short *) (pkt->data+16)) ^ 0xFFFF;

+                checksum += *((unsigned short *) (pkt->data+18)) ^ 0xFFFF;

+

+                pkt_checksum += *((unsigned short *) (pkt->data+16)) ^ 0xFFFF;

+                pkt_checksum += *((unsigned short *) (pkt->data+18)) ^ 0xFFFF;

+

+		/* Write new checksum */

+                if (!checksum) {

+                    checksum = 0xFFFF;

+                }

+                *((unsigned short *) (pkt->data+14)) = checksum;

+		if (pkt->data[13] == 6) {

+		    *((unsigned short *) (pkt->data+20+iphdr)) = pkt_checksum;

+		}

+		if (cv && (pkt->data[13] == 17) ) {

+		    *((unsigned short *) (pkt->data+10+iphdr)) = pkt_checksum;

+		}

+

+		/* Log Packet */

+		strcpy(ipstr,inet_ntoa(*( (struct in_addr *) (pkt->data+16))));

+		if (pkt->data[13] == 1) {

+		    syslog(LOG_INFO,"Open ICMP %s -> %s\n",

+			ipstr,

+			inet_ntoa(*( (struct in_addr *) (pkt->data+20))));

+		} else {

+		    syslog(LOG_INFO,"Open %s %s:%d -> %s:%d\n",

+			pkt->data[13] == 6 ? "TCP" : "UDP",

+			ipstr,

+			ntohs(*( (short *) (pkt->data+iphdr+4))),

+			inet_ntoa(*( (struct in_addr *) (pkt->data+20))),

+			ntohs(*( (short *) (pkt->data+iphdr+6))));

+                }

+            }

 	    output(0, pkt->data, pkt->length);

 	    free(pkt);

 	} else {

--- ppp/pppd/ipcp.c

+++ ppp/pppd/ipcp.c	2000/06/28 12:32:05

@@ -1454,7 +1454,7 @@

 		    proxy_arp_set[f->unit] = 1;

 	}

-	demand_rexmit(PPP_IP);

+	demand_rexmit(PPP_IP,go->ouraddr);

 	sifnpmode(f->unit, PPP_IP, NPMODE_PASS);

     } else {

--- ppp/pppd/ipv6cp.c

+++ ppp/pppd/ipv6cp.c	2000/06/28 12:32:06

@@ -1153,7 +1153,7 @@

 	    }

 	}

-	demand_rexmit(PPP_IPV6);

+	demand_rexmit(PPP_IPV6,0);

 	sifnpmode(f->unit, PPP_IPV6, NPMODE_PASS);

     } else {

--- ppp/pppd/pppd.h

+++ ppp/pppd/pppd.h	2000/06/28 12:32:06

@@ -359,7 +359,7 @@

 void demand_block __P((void));	/* set all NPs to queue up packets */

 void demand_unblock __P((void)); /* set all NPs to pass packets */

 void demand_discard __P((void)); /* set all NPs to discard packets */

-void demand_rexmit __P((int));	/* retransmit saved frames for an NP */

+void demand_rexmit __P((int, u_int32_t)); /* retransmit saved frames for an NP*/

 int  loop_chars __P((unsigned char *, int)); /* process chars from loopback */

 int  loop_frame __P((unsigned char *, int)); /* should we bring link up? */