slitheen/server/flow.h

#ifndef __RELAY_H__
#define __RELAY_H__

#include <netinet/in.h>
#include <openssl/bn.h>
#include <openssl/ssl.h>
#include "ptwist.h"
#include "slitheen.h"

#define MAX_FLOWS 10

#define TLS_HELLO_REQ 0x00
#define TLS_CLNT_HELLO 0x01
#define TLS_SERV_HELLO 0x02
#define TLS_NEW_SESS 0x04
#define TLS_CERT 0x0b
#define TLS_SRVR_KEYEX 0x0c
#define TLS_CERT_REQ 0x0d
#define TLS_SRVR_HELLO_DONE 0x0e
#define TLS_CERT_VERIFY 0x0f
#define TLS_CLNT_KEYEX 0x10
#define TLS_FINISHED 0x14

struct packet_st{
	uint32_t seq_num;
	uint16_t len;
	uint16_t data_len;
	uint8_t *data;
	struct packet_st *next;
	int incoming; //0 for outgoing, 1 for incoming
};

typedef struct queue_block_st{
	int32_t len;
	int32_t offset;
	uint8_t *data;
	struct queue_block_st *next;
	uint8_t stream_id;
} queue_block;

typedef struct data_queue_st {
	queue_block *first_block;
} data_queue;

extern data_queue *downstream_queue;

typedef struct packet_st packet;

typedef struct session_st {
	uint8_t session_id_len;
	uint8_t session_id[SSL_MAX_SSL_SESSION_ID_LENGTH];
	struct session_st *next;
	uint8_t master_secret[SSL3_MASTER_SECRET_SIZE];
	uint8_t client_random[SSL3_RANDOM_SIZE];
	uint8_t server_random[SSL3_RANDOM_SIZE];
	uint32_t session_ticket_len;
	uint8_t *session_ticket;
} session;

typedef struct session_cache_st {
	session *first_session;
	uint32_t length;
} session_cache;

typedef struct flow_st {
	struct in_addr src_ip, dst_ip; /* Source (client) and Destination (server) addresses */
	uint16_t src_port, dst_port;	/* Source and Destination ports */

	uint32_t seq_num;		/* sequence number */

	byte key[16];		/* negotiated key */
	int state;		/* TLS handshake state */
	int in_encrypted;		/* indicates whether incoming flow is encrypted */
	int out_encrypted;		/* indicates whether outgoing flow is encrypted */
	int application; /* indicates handshake is complete */
	int resume_session;
	packet *packet_chain; /* currently held data */
	queue_block *censored_queue;
	DH *dh;

	uint8_t handshake_hash[EVP_MAX_MD_SIZE];
	EVP_MD_CTX *finish_md_ctx;
	EVP_CIPHER_CTX *clnt_read_ctx;
	EVP_CIPHER_CTX *clnt_write_ctx;
	EVP_CIPHER_CTX *srvr_read_ctx;
	EVP_CIPHER_CTX *srvr_write_ctx;
	EVP_MD_CTX *read_mac_ctx;
	EVP_MD_CTX *write_mac_ctx;

	uint8_t client_random[SSL3_RANDOM_SIZE];
	uint8_t server_random[SSL3_RANDOM_SIZE];
	uint8_t master_secret[SSL3_MASTER_SECRET_SIZE];

	session *current_session;

	uint8_t read_seq[8];
	uint8_t write_seq[8];

	//for downstream processing
	uint32_t remaining_record_len;
	uint8_t httpstate;
	uint32_t remaining_response_len;
	uint8_t replace_response;

	uint8_t *outbox;
	int32_t outbox_len;
	int32_t outbox_offset;

	//locking
	//pthread_mutex_t flow_lock = PTHREAD_MUTEX_INITIALIZER;

} flow;

typedef struct flow_entry_st {
	flow *f;
	struct flow_entry_st *next;
} flow_entry;

typedef struct flow_table_st {
	flow_entry *first_entry;
	int len;
} flow_table;


int init_tables(void);
flow *add_flow(flow newFlow);
int update_flow(flow *f);
int remove_flow(flow *f);
flow *check_flow(flow observed);
flow *get_flow(int index);

int init_session_cache (void);
int verify_session_id(flow *f, uint8_t *hs);
int check_session(flow *f, uint8_t *hs, uint32_t len);
int save_session_id(flow *f, uint8_t *hs);
int save_session_ticket(flow *f, uint8_t *hs, uint32_t len);

int add_packet(flow *f, struct packet_info *info);

#endif /* __RELAY_H__ */