int AnalyzeIpv6(u_char *data, int size) {
u_char *ptr = NULL;
int lest = 0;
struct ip6_hdr *ip6 = NULL;
int len = 0;
ptr = data;
lest = size;
if (lest < sizeof(struct ip6_hdr)) {
ExitWithTooLittleLengthError("ip6_hdr", lest);
}
ip6 = (struct ip6_hdr *) ptr;
ptr += sizeof(struct ip6_hdr);
lest += sizeof(struct ip6_hdr);
PrintIp6Header(ip6, stdout);
if (ip6->ip6_nxt == IPPROTO_ICMPV6) {
len = ntohs(ip6->ip6_plen);
if (checkIP6DATAchecksum(ip6, ptr, len) == 0) {
ExitWithBadChecksumError("icmp6");
}
AnalyzeIcmp6(ptr, lest);
}
else if (ip6->ip6_nxt == IPPROTO_TCP) { // next header
len =ntohs(ip6->ip6_plen); // payload length
if (checkIPDATAchecksum(ip6, ptr, len) == 0) {
ExitWithBadChecksumError("tcp6");
}
AnalyzeTcp(ptr, lest);
}
else if (ip6->ip6_nxt == IPPROTO_UDP) {
len = ntohs(ip6->ip6_plen);
if (checkIP6DATAchecksum(ip6, ptr, len) == 0) {
ExitWithBadChecksumError("udp6");
}
AnalyzeUdp(ptr, lest);
}
return 0;
}
int RewritePacket (int deviceNo, u_char *data, int size)
{
u_char *ptr;
struct ether_header *eh;
int lest, len;
ptr=data;
lest=size;
if(lest<sizeof(struct ether_header)) {
DebugPrintf("[%d]:lest(%d)<sizeof(struct ether_header)\n",deviceNo,lest);
return(-1);
}
eh=(struct ether_header *)ptr;
ptr+=sizeof(struct ether_header);
lest-=sizeof(struct ether_header);
char dMacAddr[18];
char sMacAddr[18];
// Get dMAC, sMAC
my_ether_ntoa_r(eh->ether_dhost, dMacAddr, sizeof(dMacAddr));
my_ether_ntoa_r(eh->ether_shost, sMacAddr, sizeof(sMacAddr));
// physicalNIC -> wirelessNIC
if((strncmp(sMacAddr, cliMacAddr, SIZE_MAC)==0) &&
(strncmp(dMacAddr, dev3MacAddr, SIZE_MAC)==0)) {
my_ether_aton_r(apMacAddr, eh->ether_dhost);
my_ether_aton_r(dev1MacAddr, eh->ether_shost);
// Case: IP
if (ntohs(eh->ether_type)==ETHERTYPE_IP) {
struct iphdr *iphdr;
u_char option[1500];
int optLen;
iphdr=(struct iphdr *)ptr;
ptr+=sizeof(struct iphdr);
lest-=sizeof(struct iphdr);
optLen=iphdr->ihl*4-sizeof(struct iphdr);
if(optLen>0) {
memcpy(option, ptr, optLen);
ptr+=optLen;
lest-=optLen;
}
// Rewrite IP Address
if(iphdr->saddr==inet_addr(cliIpAddr)) {
iphdr->saddr=inet_addr(dev1IpAddr);
}
iphdr->check=0;
iphdr->check=calcChecksum2((u_char *)iphdr, sizeof(struct iphdr), option, optLen);
// Case : TCP
if(iphdr->protocol==IPPROTO_TCP) {
struct tcphdr *tcphdr;
len=ntohs(iphdr->tot_len)-iphdr->ihl*4;
tcphdr=(struct tcphdr *)ptr;
tcphdr->check=0;
tcphdr->check=checkIPDATAchecksum(iphdr, ptr, len);
}
// Case : UDP
if(iphdr->protocol==IPPROTO_UDP) {
struct udphdr* udphdr;
len=ntohs(iphdr->tot_len)-iphdr->ihl*4;
udphdr=(struct udphdr *)ptr;
udphdr->check=0;
}
}
}
// wirelessNIC -> physicalNIC
else if (strncmp(dMacAddr, dev1MacAddr, SIZE_MAC)==0) {
my_ether_aton_r(cliMacAddr, eh->ether_dhost);
my_ether_aton_r(dev3MacAddr, eh->ether_dhost);
// Case: IP
if (ntohs(eh->ether_type)==ETHERTYPE_IP) {
struct iphdr *iphdr;
u_char option[1500];
int optLen;
iphdr=(struct iphdr *)ptr;
ptr+=sizeof(struct iphdr);
lest-=sizeof(struct iphdr);
optLen=iphdr->ihl*4-sizeof(struct iphdr);
if(optLen>0) {
memcpy(option, ptr, optLen);
ptr+=optLen;
lest-=optLen;
}
// Rewrite IP Address
if(iphdr->daddr==inet_addr(dev1IpAddr)) {
iphdr->daddr=inet_addr(cliIpAddr);
}
iphdr->check=0;
iphdr->check=calcChecksum2((u_char *)iphdr, sizeof(struct iphdr), option, optLen);
// Case : TCP
if(iphdr->protocol==IPPROTO_TCP) {
struct tcphdr *tcphdr;
len=ntohs(iphdr->tot_len)-iphdr->ihl*4;
tcphdr=(struct tcphdr *)ptr;
tcphdr->check=0;
tcphdr->check=checkIPDATAchecksum(iphdr, ptr, len);
}
// Case : UDP
if(iphdr->protocol==IPPROTO_UDP) {
struct udphdr* udphdr;
len=ntohs(iphdr->tot_len)-iphdr->ihl*4;
udphdr=(struct udphdr *)ptr;
udphdr->check=0;
}
}
}
return(0);
}
int AnalyzeIp(u_char *data, int size) {
u_char *ptr = NULL;
int lest = 0;
struct iphdr *iphdr = NULL; // IPヘッダ
u_char *option = NULL; // ヘッダオプション
int optionLen = 0; // ヘッダオプションサイズ
int len = 0;
unsigned short sum = 0;
ptr = data; // IPヘッダの先頭ポインタ
lest = size;
if (lest < sizeof(struct iphdr)) {
ExitWithTooLittleLengthError("iphdr", lest);
}
iphdr = (struct iphdr *) ptr; // IPヘッダの先頭ポインタ
ptr += sizeof(struct iphdr); // IPヘッダオプションの先頭ポインタ
lest -= sizeof(struct iphdr);
// ヘッダオプションサイズを求める（パディングを含む）
optionLen = iphdr->ihl * 4 - sizeof(struct iphdr);
if (optionLen > 0) {
if (optionLen >= 1500) {
fprintf(stderr, "IP optionLen(%d):too big\n", optionLen);
}
option = ptr; // IPヘッダオプションの先頭ポインタ
ptr += optionLen; // ペイロードの先頭ポインタ
lest -= optionLen;
}
if (checkIPchecksum(iphdr, option, optionLen) == 0) {
ExitWithBadChecksumError("ip");
}
PrintIpHeader(iphdr, option, optionLen, stdout);
if (iphdr->protocol == IPPROTO_ICMP) {
// ペイロードサイズを取得する
// tot_lenはペイロードを含めたIPヘッダのサイズ
len = ntohs(iphdr->tot_len) - iphdr->ihl * 4;
sum = checksum(ptr, len); // ペイロードのチェックサムを取得する
if (sum != 0 && sum != 0xFFFF) {
ExitWithBadChecksumError("icmp");
}
AnalyzeIcmp(ptr, lest);
}
else if (iphdr->protocol == IPPROTO_TCP) {
// ペイロードサイズを取得する
len = ntohs(iphdr->tot_len) - iphdr->ihl * 4;
if (checkIPDATAchecksum(iphdr, ptr, len) == 0) {
ExitWithBadChecksumError("tcp");
}
AnalyzeTcp(ptr, lest);
}
else if (iphdr->protocol == IPPROTO_UDP) {
struct udphdr *udphdr;
udphdr = (struct udphdr *) ptr;
len = ntohs(iphdr->tot_len) - iphdr->ihl * 4;
if (udphdr->check != 0 && checkIPDATAchecksum(iphdr, ptr, len) == 0) {
ExitWithBadChecksumError("udp");
}
AnalyzeUdp(ptr, lest);
}
return 0;
}
int AnalyzeIp(u_char *data,int size)
{
u_char *ptr;
int lest;
struct iphdr *iphdr;
u_char *option;
int optionLen,len;
unsigned short sum;
ptr=data;
lest=size;
if(lest<sizeof(struct iphdr)){
if(fil[2] == 1 || fil[3] == 1 || fil[4] == 1 || fil [6] == 1){
fprintf(stderr,"lest(%d)<sizeof(struct iphdr)\n",lest);
}
return(-1);
}
iphdr=(struct iphdr *)ptr;
ptr+=sizeof(struct iphdr);
lest-=sizeof(struct iphdr);
optionLen=iphdr->ihl*4-sizeof(struct iphdr);
if(optionLen>0){
if(optionLen>=1500){
if(fil[2] == 1 || fil[3] == 1 || fil[4] == 1 || fil[6] == 1){
fprintf(stderr,"IP optionLen(%d):too big\n",optionLen);
}
return(-1);
}
option=ptr;
ptr+=optionLen;
lest-=optionLen;
}
if(checkIPchecksum(iphdr,option,optionLen)==0){
fprintf(stderr,"bad ip checksum\n");
return(-1);
}
if(fil[6] == 1){
PrintIpHeader(iphdr,option,optionLen,stdout);
}
if(iphdr->protocol==IPPROTO_ICMP){
len=ntohs(iphdr->tot_len)-iphdr->ihl*4;
sum=checksum(ptr,len);
if(sum!=0&&sum!=0xFFFF){
fprintf(stderr,"bad icmp checksum\n");
return(-1);
}
AnalyzeIcmp(ptr,lest);
}
else if(iphdr->protocol==IPPROTO_TCP){
len=ntohs(iphdr->tot_len)-iphdr->ihl*4;
if(checkIPDATAchecksum(iphdr,ptr,len)==0){
fprintf(stderr,"bad tcp checksum\n");
return(-1);
}
AnalyzeTcp(ptr,lest);
}
else if(iphdr->protocol==IPPROTO_UDP){
struct udphdr *udphdr;
udphdr=(struct udphdr *)ptr;
len=ntohs(iphdr->tot_len)-iphdr->ihl*4;
if(udphdr->check!=0&&checkIPDATAchecksum(iphdr,ptr,len)==0){
fprintf(stderr,"bad udp checksum\n");
return(-1);
}
AnalyzeUdp(ptr,lest);
}
return(0);
}
