ntp and udp

1 files changed, 29 insertions, 0 deletions

diff --git a/net/ipv4.c b/net/ipv4.c
index b7e6a53..b090a7b 100644
--- a/net/ipv4.c
+++ b/net/ipv4.c
@@ -11,6 +11,7 @@ bool ipv4_incoming(struct netdev *dev,struct eth_hdr *hdr)
     ipv4->csum=0;
     klog("expected checksum: 0x%04X",checksum(ipv4,ntohs(ipv4->len)));
     klog("ipv4 header len=%d",ipv4->ihl);
+
     if(ipv4->proto==IPV4_P_ICMP)
     {
 	icmp_incoming(dev,hdr);
@@ -18,3 +19,31 @@ bool ipv4_incoming(struct netdev *dev,struct eth_hdr *hdr)
 
     return true;
 }
+
+uint32_t ipv4_generic(struct netdev *dev, uint32_t ip, uint8_t type, uint8_t* pos,uint8_t *end)
+{
+
+    pos-=20; // we need 20 bytes for the ipv4 header.
+    struct ipv4_hdr *ipv4=pos;
+    ipv4->ihl=5; // 20 bytes
+    ipv4->version=4; // ipv 4
+
+    ipv4->tos=0;	 // type of service?
+    ipv4->len=htons(end-pos);	 // total length of ip datagramm in bytes
+    ipv4->id=0;		 // index of datagram for fragmentation
+
+    //ipv4->flags=0x2;	 // various control flags 0x20 do not fragment
+    //ipv4->frag_offset=0; // fragment offset 0 - first
+    ipv4->flags_and_offset=0; // TODO! 0x2?
+
+    ipv4->ttl=64;	 // time to live - countdown decreased by each receiver
+    ipv4->proto=type;    // payload protocol / 1-icmp, 16 - udp , 6 -tcp
+    ipv4->csum=0;	 // header checksum
+    ipv4->saddr=dev->ip; // source ip address
+    ipv4->daddr=ip;	    // destination ip address
+
+    //ipv4->csum=checksum(ipv4,ntohs(ipv4->len));
+    ipv4->csum=checksum(ipv4,20);
+
+    return eth_generic(dev,ip,ETH_P_IPV4,pos,end);
+}