Checksum computation!

[dccp2tcp] / dccp2tcp.c

diff --git a/dccp2tcp.c b/dccp2tcp.c
index f7756612ea9130851974a2490306924dbd03f6ba..fb648cf2f8e4508f56eb71264a8295d6a4c41ce6 100644 (file)
--- a/dccp2tcp.c
+++ b/dccp2tcp.c
@@ -23,9 +23,8 @@ Date: 11/2012
 Notes:
        1)CCID2 ONLY
        2)DCCP MUST use 48 bit sequence numbers
-       3)Checksums are not computed (they are zeroed)
-       4)DCCP DATA packets are not implemented (Linux doesn't use them)
-       5)DCCP Ack packets show up as TCP packets containing one byte
+       3)DCCP DATA packets are not implemented (Linux doesn't use them)
+       4)DCCP Ack packets show up as TCP packets containing one byte
 ******************************************************************************/
 #include "dccp2tcp.h"
 
@@ -204,6 +203,7 @@ return;
 /*do all the dccp to tcp conversions*/
 int convert_packet(struct packet *new, const struct const_packet* old)
 {
+       struct tcphdr                           *tcph;
        struct dccp_hdr                         *dccph;
        struct dccp_hdr_ext             *dccphex;
        struct host                                     *h1=NULL;
@@ -221,6 +221,7 @@ int convert_packet(struct packet *new, const struct const_packet* old)
        }
 
        /*cast header pointers*/
+       tcph=(struct tcphdr*)new->data;
        dccph=(struct dccp_hdr*)old->data;
        dccphex=(struct dccp_hdr_ext*)(old->data+sizeof(struct dccp_hdr));
 
@@ -246,13 +247,32 @@ int convert_packet(struct packet *new, const struct const_packet* old)
 
        /*TODO: Add CCID detection*/
        if(h1->type==CCID2 && h2->type==CCID2){
-               return ccid2_convert_packet(new,old);
+               if(ccid2_convert_packet(new,old)==0){
+                       return 0;
+               }
        }
        if(h1->type==CCID3 && h2->type==CCID3){
-               //return ccid3_convert_packet(new,old);
+               //ccid3_convert_packet(new,old);
+       }
+       if(ccid2_convert_packet(new,old)==0){
+               return 0;
+       }
+
+       /*Compute TCP checksums*/
+       if(new->id_len==IP4_ADDR_LEN){
+                       tcph->check=0;
+                       tcph->check=ipv4_pseudohdr_chksum(new->data,
+                                       new->length, new->dest_id, new->src_id, 6);
+       }else if(new->id_len==IP6_ADDR_LEN){
+                       tcph->check=0;
+                       tcph->check=ipv6_pseudohdr_chksum(new->data,
+                                       new->length, new->dest_id, new->src_id, 6);
+       }else{
+               tcph->check=0;
+               dbgprintf(2,"Unknown ID Length, can't do checksums");
        }
 
-       return ccid2_convert_packet(new,old);
+       return 1;
 }
 
 void version(){