moved shared functions from slitheen.c (which contains main()) to a new file packet.c

relay_station/Makefile

@@ -4,9 +4,9 @@ TARGETS=slitheen
 
 all: $(TARGETS)
 
-slitheen.o flow.o ptwist168.o crypto.o relay.o cryptothread.o util.o:: ptwist.h flow.h slitheen.h crypto.h relay.h cryptothread.h util.h
+slitheen.o packet.o flow.o ptwist168.o crypto.o relay.o cryptothread.o util.o:: ptwist.h flow.h packet.h slitheen.h crypto.h relay.h cryptothread.h util.h
 
-slitheen: slitheen.o flow.o ptwist168.o crypto.o relay.o cryptothread.o util.o relay.h crypto.h ptwist.h flow.h slitheen.h cryptothread.h util.h
+slitheen: slitheen.o packet.o flow.o ptwist168.o crypto.o relay.o cryptothread.o util.o relay.h crypto.h ptwist.h flow.h packet.h slitheen.h cryptothread.h util.h
 	gcc -g -ggdb -o $@ $^ -L/usr/local/lib -I/usr/local/include -lssl -lcrypto -lpcap -lpthread -ldl
 
 clean:

relay_station/crypto.c

@@ -145,7 +145,7 @@
 #include "ptwist.h"
 #include "crypto.h"
 #include "flow.h"
-#include "slitheen.h"
+#include "packet.h"
 #include "util.h"
 #include "relay.h"
 

relay_station/flow.c

@@ -39,7 +39,7 @@
 
 #include "flow.h"
 #include "crypto.h"
-#include "slitheen.h"
+#include "packet.h"
 #include "relay.h"
 #include "util.h"
 

relay_station/flow.h

@@ -35,7 +35,7 @@
 #include <openssl/modes.h>
 #include <openssl/aes.h>
 #include "ptwist.h"
-#include "slitheen.h"
+#include "packet.h"
 #include "util.h"
 
 #define MAX_FLOWS 10

relay_station/packet.c

@@ -0,0 +1,76 @@
+/* Name: packet.c 
+ *
+ * Slitheen - a decoy routing system for censorship resistance
+ * Copyright (C) 2017 Cecylia Bocovich (cbocovic@uwaterloo.ca)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Additional permission under GNU GPL version 3 section 7
+ * 
+ * If you modify this Program, or any covered work, by linking or combining
+ * it with the OpenSSL library (or a modified version of that library), 
+ * containing parts covered by the terms of the OpenSSL Licence and the
+ * SSLeay license, the licensors of this Program grant you additional
+ * permission to convey the resulting work. Corresponding Source for a
+ * non-source form of such a combination shall include the source code
+ * for the parts of the OpenSSL library used as well as that of the covered
+ * work.
+ */
+
+#include <pcap.h>
+#include "packet.h"
+#include "util.h"
+
+/** Copies a packet_info structure and returns a pointer to the duplicate.
+*/
+struct packet_info *copy_packet_info(struct packet_info *src_info){
+    struct packet_info *dst_info = emalloc(sizeof(struct packet_info));
+
+    dst_info->ip_hdr = src_info->ip_hdr;
+    dst_info->tcp_hdr = src_info->tcp_hdr;
+
+    dst_info->size_tcp_hdr = src_info->size_tcp_hdr;
+    dst_info->size_ip_hdr = src_info->size_ip_hdr;
+
+    dst_info->app_data = src_info->app_data;
+    dst_info->app_data_len = src_info->app_data_len;
+
+    return dst_info;
+}
+
+
+/*
+ * Injects a packet back out the opposite interface
+ */
+void inject_packet(struct inject_args *iargs, const struct pcap_pkthdr *header, uint8_t *packet){
+    pcap_t *handle = iargs->write_dev;
+
+    //write back out to the MAC ADDR it came in on
+    //memmove(packet, packet+ETHER_ADDR_LEN, ETHER_ADDR_LEN);
+    //memcpy(packet+ETHER_ADDR_LEN, iargs->mac_addr, ETHER_ADDR_LEN);
+
+    if((pcap_inject(handle, packet, header->len)) < 0 ){
+        fprintf(stderr, "Error: %s\n", pcap_geterr(handle));
+        printf("Length: %d\n", header->len);
+    }
+
+#ifdef DEBUG_EXTRA
+    fprintf(stderr, "injected the following packet:\n");
+    for(int i=0; i< header->len; i++){
+        fprintf(stderr, "%02x ", packet[i]);
+    }
+    fprintf(stderr, "\n");
+
+#endif
+    free(packet);
+}

relay_station/packet.h

@@ -0,0 +1,133 @@
+/* Slitheen - a decoy routing system for censorship resistance
+ * Copyright (C) 2017 Cecylia Bocovich (cbocovic@uwaterloo.ca)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Additional permission under GNU GPL version 3 section 7
+ * 
+ * If you modify this Program, or any covered work, by linking or combining
+ * it with the OpenSSL library (or a modified version of that library), 
+ * containing parts covered by the terms of the OpenSSL Licence and the
+ * SSLeay license, the licensors of this Program grant you additional
+ * permission to convey the resulting work. Corresponding Source for a
+ * non-source form of such a combination shall include the source code
+ * for the parts of the OpenSSL library used as well as that of the covered
+ * work.
+ */
+#ifndef PACKET_H
+#define PACKET_H
+
+#include <pcap.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <netinet/in.h>
+
+/* Ethernet addresses are 6 bytes */
+#define ETHER_ADDR_LEN	6
+#define ETHER_HEADER_LEN  2*ETHER_ADDR_LEN + 2
+
+/* Definitions for parsing packet data */
+struct ip_header {
+    u_char versionihl;		/* Version >> 4 | IHL & 0x0f */
+    u_char dscpecn;		/* DSCP >> 2 | ECN  & 0x03 */
+    u_short len;		/* Total Length */
+    u_short id;		/* Identification */
+    u_short flagsoff;		/* Flags >> 13 | Fragment Offset & 0x1fff */
+#define RF 0x8000		/* Reserved; must be zero */
+#define DF 0x4000		/* Dont Fragment */
+#define MF 0x2000		/* More Fragments */
+    u_char ttl;		/* Time To Live */
+    u_char proto;		/* Protocol */
+    u_short chksum;		/* Header Checksum */
+    struct in_addr src, dst; /* Source and Destination addresses */
+};
+#define IP_HEADER_LEN(ip)		(((ip)->versionihl) & 0x0f)*4
+
+struct tcp_header {
+    u_short src_port;	/* source port */
+    u_short dst_port;	/* destination port */
+    u_int sequence_num;		/* sequence number */
+    u_int ack_num;		/* acknowledgement number */
+    u_char offset_res_ns;	/*Data offset >> 4 |  res >> 1 | NS 0x01 */
+    u_char flags;			/* Flags */
+#define FIN 0x01
+#define RST 0x04
+    u_short win_size;		/* Window size*/
+    u_short chksum;		/* Checksum */
+    u_short urg;		/* Urgent pointer */
+};
+#define TCP_HEADER_LEN(tcp)		(((tcp)->offset_res_ns) >> 4)*4
+
+struct tls_header {
+    u_char type; /* Content Type */
+#define CCS 0x14
+#define ALERT   0x15
+#define HS  0x16
+#define APP 0x17
+#define HB  0x18
+    u_short version; /* Version */
+    u_short len; /* Length */
+    u_char msg; /* Message Type */
+#define CLIENT_HELLO 0x01
+#define FINISHED 0x14
+};
+#define RECORD_HEADER_LEN 5
+#define CLIENT_HELLO_HEADER_LEN 6
+
+struct __attribute__((__packed__)) slitheen_header {
+    uint64_t counter;
+    uint16_t stream_id; /* determines which stream the data is from */
+    uint16_t len;
+    uint16_t garbage;
+    uint16_t zeros;
+};
+
+#define SLITHEEN_HEADER_LEN 16
+
+struct __attribute__((__packed__)) record_header {
+    u_char type;
+#define HS 0x16
+    u_short version;
+    u_short len;
+};
+#define RECORD_LEN(rec)		(htons(rec->len))
+
+struct __attribute__((__packed__)) handshake_header {
+    u_char type; /*Handshake message type */
+    u_char len1;
+    u_char len2;
+    u_char len3;
+};
+#define HANDSHAKE_MESSAGE_LEN(hs)		(((hs)->len1) << 16)+(((hs)->len2) << 8)+ ((hs)->len3)
+#define HANDSHAKE_HEADER_LEN 4
+struct packet_info {
+    const struct ip_header *ip_hdr;
+    struct tcp_header *tcp_hdr;
+    const struct tls_header *record_hdr;
+
+    uint32_t size_tcp_hdr;
+    uint32_t size_ip_hdr;
+
+    uint8_t *app_data;
+    uint16_t app_data_len;
+};
+
+struct inject_args {
+    uint8_t *mac_addr;
+    pcap_t *write_dev;
+};
+
+struct packet_info *copy_packet_info(struct packet_info *src_info);
+
+void inject_packet(struct inject_args *iargs, const struct pcap_pkthdr *header, uint8_t *packet);
+#endif /* PACKET_H */

relay_station/relay.c

@@ -52,7 +52,7 @@
 #include <openssl/rand.h>
 
 #include "relay.h"
-#include "slitheen.h"
+#include "packet.h"
 #include "flow.h"
 #include "crypto.h"
 #include "util.h"

relay_station/slitheen.c

@@ -43,7 +43,13 @@
 #include "relay.h"
 #include "crypto.h"
 #include "cryptothread.h"
+#include "packet.h"
 
+void got_packet(uint8_t *args, const struct pcap_pkthdr *header, const uint8_t *packet);
+void *sniff_packets(void *);
+void process_packet(struct inject_args *iargs, const struct pcap_pkthdr *header, uint8_t *packet);
+void extract_packet_headers(uint8_t *packet, struct packet_info *info);
+struct packet_info *copy_packet_info(struct packet_info *src_info);
 
 void save_packet(flow *f, struct packet_info *info);
 void update_window_expiration(flow *f, struct packet_info *info);
@@ -159,31 +165,6 @@ void *sniff_packets(void *args){
 }
 
 
-/*
- * Injects a packet back out the opposite interface
- */
-void inject_packet(struct inject_args *iargs, const struct pcap_pkthdr *header, uint8_t *packet){
-    pcap_t *handle = iargs->write_dev;
-
-    //write back out to the MAC ADDR it came in on
-    //memmove(packet, packet+ETHER_ADDR_LEN, ETHER_ADDR_LEN);
-    //memcpy(packet+ETHER_ADDR_LEN, iargs->mac_addr, ETHER_ADDR_LEN);
-
-    if((pcap_inject(handle, packet, header->len)) < 0 ){
-        fprintf(stderr, "Error: %s\n", pcap_geterr(handle));
-        printf("Length: %d\n", header->len);
-    }
-
-#ifdef DEBUG_EXTRA
-    fprintf(stderr, "injected the following packet:\n");
-    for(int i=0; i< header->len; i++){
-        fprintf(stderr, "%02x ", packet[i]);
-    }
-    fprintf(stderr, "\n");
-
-#endif
-    free(packet);
-}
 
 /**
  * Runs when pcap_loop receives a packet from the specified interface
@@ -672,19 +653,3 @@ void extract_packet_headers(uint8_t *packet, struct packet_info *info){
 
 }
 
-/** Copies a packet_info structure and returns a pointer to the duplicate.
-*/
-struct packet_info *copy_packet_info(struct packet_info *src_info){
-    struct packet_info *dst_info = emalloc(sizeof(struct packet_info));
-
-    dst_info->ip_hdr = src_info->ip_hdr;
-    dst_info->tcp_hdr = src_info->tcp_hdr;
-
-    dst_info->size_tcp_hdr = src_info->size_tcp_hdr;
-    dst_info->size_ip_hdr = src_info->size_ip_hdr;
-
-    dst_info->app_data = src_info->app_data;
-    dst_info->app_data_len = src_info->app_data_len;
-
-    return dst_info;
-}

relay_station/slitheen.h

@@ -27,116 +27,14 @@
  */
 #ifndef SLITHEEN_H
 #define SLITHEEN_H
-#include <stdlib.h>
-#include <netinet/in.h>
+#include <stdint.h>
 #include <pcap.h>
 
-/* Ethernet addresses are 6 bytes */
-#define ETHER_ADDR_LEN	6
-#define ETHER_HEADER_LEN  2*ETHER_ADDR_LEN + 2
-
-/* Definitions for parsing packet data */
-struct ip_header {
-    u_char versionihl;		/* Version >> 4 | IHL & 0x0f */
-    u_char dscpecn;		/* DSCP >> 2 | ECN  & 0x03 */
-    u_short len;		/* Total Length */
-    u_short id;		/* Identification */
-    u_short flagsoff;		/* Flags >> 13 | Fragment Offset & 0x1fff */
-#define RF 0x8000		/* Reserved; must be zero */
-#define DF 0x4000		/* Dont Fragment */
-#define MF 0x2000		/* More Fragments */
-    u_char ttl;		/* Time To Live */
-    u_char proto;		/* Protocol */
-    u_short chksum;		/* Header Checksum */
-    struct in_addr src, dst; /* Source and Destination addresses */
-};
-#define IP_HEADER_LEN(ip)		(((ip)->versionihl) & 0x0f)*4
-
-struct tcp_header {
-    u_short src_port;	/* source port */
-    u_short dst_port;	/* destination port */
-    u_int sequence_num;		/* sequence number */
-    u_int ack_num;		/* acknowledgement number */
-    u_char offset_res_ns;	/*Data offset >> 4 |  res >> 1 | NS 0x01 */
-    u_char flags;			/* Flags */
-#define FIN 0x01
-#define RST 0x04
-    u_short win_size;		/* Window size*/
-    u_short chksum;		/* Checksum */
-    u_short urg;		/* Urgent pointer */
-};
-#define TCP_HEADER_LEN(tcp)		(((tcp)->offset_res_ns) >> 4)*4
-
-struct tls_header {
-    u_char type; /* Content Type */
-#define CCS 0x14
-#define ALERT   0x15
-#define HS  0x16
-#define APP 0x17
-#define HB  0x18
-    u_short version; /* Version */
-    u_short len; /* Length */
-    u_char msg; /* Message Type */
-#define CLIENT_HELLO 0x01
-#define FINISHED 0x14
-};
-#define RECORD_HEADER_LEN 5
-#define CLIENT_HELLO_HEADER_LEN 6
-
-struct packet_info {
-    const struct ip_header *ip_hdr;
-    struct tcp_header *tcp_hdr;
-    const struct tls_header *record_hdr;
-
-    uint32_t size_tcp_hdr;
-    uint32_t size_ip_hdr;
-
-    uint8_t *app_data;
-    uint16_t app_data_len;
-};
-
-struct __attribute__((__packed__)) slitheen_header {
-    uint64_t counter;
-    uint16_t stream_id; /* determines which stream the data is from */
-    uint16_t len;
-    uint16_t garbage;
-    uint16_t zeros;
-};
-
-#define SLITHEEN_HEADER_LEN 16
-
-struct __attribute__((__packed__)) record_header {
-    u_char type;
-#define HS 0x16
-    u_short version;
-    u_short len;
-};
-#define RECORD_LEN(rec)		(htons(rec->len))
-
-struct __attribute__((__packed__)) handshake_header {
-    u_char type; /*Handshake message type */
-    u_char len1;
-    u_char len2;
-    u_char len3;
-};
-#define HANDSHAKE_MESSAGE_LEN(hs)		(((hs)->len1) << 16)+(((hs)->len2) << 8)+ ((hs)->len3)
-#define HANDSHAKE_HEADER_LEN 4
 
 struct sniff_args {
     char *readdev;
     char *writedev;
 };
 
-struct inject_args {
-    uint8_t *mac_addr;
-    pcap_t *write_dev;
-};
-
-void got_packet(uint8_t *args, const struct pcap_pkthdr *header, const uint8_t *packet);
-void *sniff_packets(void *);
-void process_packet(struct inject_args *iargs, const struct pcap_pkthdr *header, uint8_t *packet);
-void extract_packet_headers(uint8_t *packet, struct packet_info *info);
-struct packet_info *copy_packet_info(struct packet_info *src_info);
-void inject_packet(struct inject_args *iargs, const struct pcap_pkthdr *header, uint8_t *packet);
 
 #endif /* _SLITHEEN_H_ */