C++ (Cpp) tcp_sum_calc Examples

Example #1

File: sessioncleanup.c Project: gvsurenderreddy/solowan

/*
 * This sends a keep alive message to the specified IP.
 * It does not tag the packet with the Accelerator ID this
 * prevents the keepalive messages from recreating dead sessions
 * in remote Accelerators.
 */
void sendkeepalive
(__u32 saddr, __u16 source, __u32 seq,
__u32 daddr, __u16 dest, __u32 ack_seq){
	char packet[BUFSIZE];
	struct iphdr *iph = NULL;
	struct tcphdr *tcph = NULL;
	struct sockaddr_in sin, din;
	__u16 tcplen;

	memset(packet, 0, BUFSIZE);

	sin.sin_family = AF_INET;
	din.sin_family = AF_INET;
	
	sin.sin_port = source;
	din.sin_port = dest;
	
	sin.sin_addr.s_addr = saddr;
	din.sin_addr.s_addr = daddr;

	iph = (struct iphdr *)packet;
	iph->ihl = 5; // IP header length.
	iph->version = 4; // IP version 4.
	iph->tos = 0; // No TOS.
	iph->tot_len=htons(sizeof(struct iphdr) + sizeof(struct tcphdr)); // L3 + L4 header length.
	iph->id = 0; // What?
	iph->frag_off = 0; // No fragmenting.
	iph->ttl = 64; // Set a TTL.
	iph->protocol = IPPROTO_TCP; // TCP protocol.
	iph->check = 0; // No IP checksum yet.
	iph->saddr = saddr; // Source IP.
	iph->daddr = daddr; // Dest IP.
	
	tcph = (struct tcphdr *) (((u_int32_t *)iph) + iph->ihl);
	tcph->check = 0; // No TCP checksum yet.
	tcph->source = source; // Source TCP Port.
	tcph->dest = dest; // Destination TCP Port.
	tcph->seq = htonl(seq - 1); // Current SEQ minus one is used for TCP keepalives.
	tcph->ack_seq = htonl( ack_seq - 1); // Ummm not sure yet.
	tcph->res1 = 0; // Not sure.
	tcph->doff = 5; // TCP Offset.  At least 5 if there are no TCP options.
	tcph->fin = 0; // FIN flag.
	tcph->syn = 0; // SYN flag.
	tcph->rst = 0; // RST flag.
	tcph->psh = 0; // PSH flag.
	tcph->ack = 1; // ACK flag.
	tcph->urg = 0; // URG flag.
	
	__set_tcp_option((__u8 *)iph,32,6,localID); // Add the Accelerator ID to this packet.
	
	tcplen = ntohs(iph->tot_len) - iph->ihl*4;
	tcph->check = 0;
	tcph->check = tcp_sum_calc(tcplen,
		(unsigned short *)&iph->saddr,
		(unsigned short *)&iph->daddr,
		(unsigned short *)tcph);
 	iph->check = 0;
 	iph->check = ip_sum_calc(iph->ihl*4,
		(unsigned short *)iph);
	
	
	if(sendto(rawsock, packet, ntohs(iph->tot_len), 0, (struct sockaddr *)&din, sizeof(din)) < 0){
		printf("sendto() error\n");
	}
	
	return;
}

Example #2

File: sessioncleanup.c Project: solowan/solowan

/*
 * This sends a keep alive message to the specified IP.
 * It does not tag the packet with the Accelerator ID this
 * prevents the keepalive messages from recreating dead sessions
 * in remote Accelerators.
 */
void sendkeepalive
(__u32 saddr, __u16 source, __u32 seq,
__u32 daddr, __u16 dest, __u32 ack_seq){
	char packet[BUFSIZE];
	struct iphdr *iph = NULL;
	struct tcphdr *tcph = NULL;
	//struct sockaddr_in sin;
	struct sockaddr_in din;
	__u16 tcplen;

	memset(packet, 0, BUFSIZE);

	//sin.sin_family = AF_INET;
	din.sin_family = AF_INET;
	
	//sin.sin_port = source;
	din.sin_port = dest;
	
	//sin.sin_addr.s_addr = saddr;
	din.sin_addr.s_addr = daddr;

	iph = (struct iphdr *)packet;
	iph->ihl = 5; // IP header length.
	iph->version = 4; // IP version 4.
	iph->tos = 0; // No TOS.
	iph->tot_len=htons(sizeof(struct iphdr) + sizeof(struct tcphdr)); // L3 + L4 header length.
	iph->id = 0; // What?
	iph->frag_off = 0; // No fragmenting.
	iph->ttl = 64; // Set a TTL.
	iph->protocol = IPPROTO_TCP; // TCP protocol.
	iph->check = 0; // No IP checksum yet.
	iph->saddr = saddr; // Source IP.
	iph->daddr = daddr; // Dest IP.
	
	tcph = (struct tcphdr *) (((u_int32_t *)iph) + iph->ihl);
	tcph->check = 0; // No TCP checksum yet.
	tcph->source = source; // Source TCP Port.
	tcph->dest = dest; // Destination TCP Port.
	tcph->seq = htonl(seq - 1); // Current SEQ minus one is used for TCP keepalives.
	tcph->ack_seq = htonl( ack_seq - 1); // Ummm not sure yet.
	tcph->res1 = 0; // Not sure.
	tcph->doff = 5; // TCP Offset.  At least 5 if there are no TCP options.
	tcph->fin = 0; // FIN flag.
	tcph->syn = 0; // SYN flag.
	tcph->rst = 0; // RST flag.
	tcph->psh = 0; // PSH flag.
	tcph->ack = 1; // ACK flag.
	tcph->urg = 0; // URG flag.
	
	if (__set_tcp_option((__u8 *)iph,32,3,2) == -1) { // Add the Accelerator ID to this packet.
		LOGDEBUG(lc_sesman, "Sessioncleanup: Cannot add accelerator ID, sessioncleanup.c, IP datagram ID %x, current value of TCP doff %d",ntohs(iph->id), tcph->doff);
	} else {
    		unsigned char *tcpdata =  (unsigned char *) tcph + tcph->doff * 4; // Find starting location of the TCP data.
                pOpennopHeader oh = (pOpennopHeader) tcpdata;
                oh->opennopID = localID;
                oh->seqNo = 0;
                oh->compression = 0;
                oh->deduplication = 0;
                oh->reasonForNoOptimization = NOT_RELEVANT;
                oh->queuenum = 0;
                oh->pattern = OPENNOP_PATTERN;
                iph->tot_len = htons(ntohs(iph->tot_len)+sizeof(OpennopHeader));
	}
	
	tcplen = ntohs(iph->tot_len) - iph->ihl*4;
	tcph->check = 0;
	tcph->check = tcp_sum_calc(tcplen,
		(unsigned short *)&iph->saddr,
		(unsigned short *)&iph->daddr,
		(unsigned short *)tcph);
 	iph->check = 0;
 	iph->check = ip_sum_calc(iph->ihl*4,
		(unsigned short *)iph);
	
	
	if(sendto(rawsock, packet, ntohs(iph->tot_len), 0, (struct sockaddr *)&din, sizeof(din)) < 0){
		printf("sendto() error\n");
	}
	
	return;
}