slitheen/server/flow.c

#include <stdio.h>
#include <stdlib.h>
#include "flow.h"

static flow_table *table;

/* Initialize the table of tagged flows */
int init_flow_table(void) {

	table = malloc(sizeof(flow_table));
	
	table->table = (flow *) malloc(sizeof(flow)*MAX_FLOWS);
	if( table->table == NULL){
		fprintf(stderr, "malloc failed.\n");
		return 1;
	}
	table->len = 0;
	table->max_len = MAX_FLOWS;

	return 0;
}


/* Add a new flow to the tagged flow table */
int add_flow(flow newFlow) {
	flow *ptr;

	if(table->len == table->max_len){
		//grow_table();
		return(1);
	}
	printf("there are %d flows in the table\n", table->len);

	ptr = table->table + table->len;
	newFlow.tls_state = 1;
	newFlow.encrypted = 0;
	*ptr = newFlow;

	table->len ++;

	return(0);
}

int update_flow(int index, int code) {
	flow *f;
	f = get_flow(index-1);
	int state = 0;
	switch(code){
		case 1: state = state | TLS_CLNT_HELLO; 
				break;
		case 2: state = state | TLS_SERV_HELLO; 
				break;
		case 4: state = state | TLS_NEW_SESS; 
				break;
		case 16: state = state | TLS_KEY_EXCHG; 
				break;
		case 20: state = state | TLS_FINISHED; 
				break;
	}
	f->tls_state = state;
	return 0;
}

int remove_flow(int index) {
	int i;
	flow *ptr;

	if(index){
		ptr = table->table + index -1;
		for(i=0; i< table->len - index; i++){
			ptr += i;
			*ptr = *(ptr + 1);
		}
		table->len --;
	} else {
		return 1;
	}

	printf("flow removed!\n");
	return 0;
}

int grow_table() {
	return 0;
}

int check_flow(flow observed){
	/* Loop through flows in table and see if it exists */
	int i;
	flow *candidate = table->table;

	/* Check first in this direction */
	for(i=0; i<table->len; i++){
		candidate += i;
		if(candidate->src_ip.s_addr == observed.src_ip.s_addr){
			if(candidate->dst_ip.s_addr == observed.dst_ip.s_addr){
				if(candidate->src_port == observed.src_port){
					if(candidate->dst_port == observed.dst_port){
						return i+1;
					}
				}
			}
		}
	}


	candidate = table->table;
	/* Then in the other direction */
	for(i=0; i<table->len; i++){
		candidate += i;
		if(candidate->src_ip.s_addr == observed.dst_ip.s_addr){
			if(candidate->dst_ip.s_addr == observed.src_ip.s_addr){
				if(candidate->src_port == observed.dst_port){
					if(candidate->dst_port == observed.src_port){
						return i+1;
					}
				}
			}
		}
	}

	return 0;
}

flow *get_flow(int index){
	if(index < table->len){
		return table->table+index;
	} else {
		return NULL;
	}
}