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- /*
- * Main Author & Publisher: Yazan H. Siam (tcpliveplay@gmail.com)
- * File: tcpliveplay.c
- * Started as a Senior Design project @ North Carolina State University
- * Last Updated Date: September 5, 2012
- *
- */
- /**
- * Program Description:
- * This program, 'tcpliveplay' replays a captured set of packets using new TCP connections with the
- * captured TCP payloads against a remote host in order to do comprehensive vulnerability testings.
- * This program takes in a "*.pcap" file that contains only one tcp flow connection and replays it
- * against a live host exactly how the captured packets are laid out. At the beginning, the program
- * establishes who the 'client' is and the 'server' is based on who initiates the SYN compares each
- * packet's source ip against the ip of the 'client' (which is named local in the code) and the 'server'
- * (remote) to correctly determine the expected seqs & acks. This also extracts the MACs of both local
- * and remote clients. The program is also capable of rewriting the local and remote MAC & IP so that
- * the packets are properly replayed when used on live networks. The current state of the program is that
- * it takes in a pcap file on command line and writes a new file called "newfile.pcap" which is used thereafter
- * for the rest of the program's calculations and set expectations. The program prints out a summary of the
- * new file on the command prompt. Once the program is done, "newfile.pcap" is cleaned up.
- * Program Design Overview:
- * Before replaying the packets, the program reads in the pcap file that contains one tcp flow,
- * and takes the SEQ/ACK #s.
- * Based on the number of packets, a struct schedule of events are is set up. Based on
- * the SEQ/ACK numbers read in, the schedule is setup to be relative numbers rather than
- * absolute. This is done by starting with local packets, subtracting the first SEQ (which
- * is that of the first SYN packet) from all the SEQs of the local packets then by subtracting
- * the first remote sequence (which is that of the SYN-ACK packet) from all the local packet's
- * ACKs. After the local side SEQ/ACK numbers are fixed to relative numbers, 'lseq_adjust'
- * the locally generated random number for the SYN packet gets added to all the local SEQs
- * to adjust the schedule to absolute number configuration. Then doing the remote side is similar
- * except we only fix the remote ACKs based on our locally generated random number because
- * we do not yet know the remote random number of the SYN-ACK packet. This means that at this
- * point the entire schedule of local packets and remote packets are set in such a way that
- * the local packets' SEQ's are absolute, but ACKs are relative and the remote packets' SEQ's are
- * relative but ACKs as absolute. Once this is set, the replay starts by sending first SYN packet.
- * If the remote host's acks with the SYN packet_SEQ+1 then we save their remote SEQ and adjust
- * the local ACKs and remote SEQs in the struct schedule to be absolute based this remote SEQ.
- * From this point on forward, we know or 'expect' what the remote host's ACKs and SEQs are exactly.
- * If the remote host responds correctly as we expect (checking the schedule position expectation
- * as packets are received) then we proceed in the schedule whether the next event is to send a local
- * packet or wait for a remote packet to arrive.
- *
- * Usage: tcpliveplay <eth0/eth1> <file.pcap> <Destination IP [1.2.3.4]> <Destination mac [0a:1b:2c:3d:4e:5f]> <'random'
- dst port OR specify dport #>
- *
- * Example:
- * yhsiam@yhsiam-VirtualBox:~$ tcpliveplay eth0 test1.pcap 192.168.1.4 52:57:01:11:31:92 random
- *
- * NOTE: This program may not completely replay the packets due to the remote host responding in an unexpected
- * fashion such as responding with packets never seen in the given *.pcap file or coupling packets together, etc.
- * if you have any suggestion on improving this software or if you find any bugs, please let me know at my
- * email: tcpliveplay@gmail.com
- *
- * Past Contributors (Last contributed May 4, 2012): Andrew Leonard & Beau Luck
- *
- */
- #include "tcpliveplay.h"
- #include "config.h"
- #include "common/sendpacket.h"
- #include "common/utils.h"
- #include "tcpliveplay_opts.h"
- #include <arpa/inet.h>
- #include <net/if.h>
- #include <netinet/in.h>
- #include <signal.h>
- #include <stdbool.h>
- #include <stdio.h>
- #include <stdlib.h>
- #include <string.h>
- #include <sys/ioctl.h>
- #include <sys/socket.h>
- #include <sys/types.h>
- #include <unistd.h>
- volatile int didsig;
- #ifdef DEBUG /* set -DDEBUG=1 */
- int debug = 0;
- #endif
- pcap_t *set_live_filter(char *dev, input_addr *hostip, unsigned int port);
- pcap_t *set_offline_filter(char *file);
- pcap_t *live_handle;
- unsigned int sched_index = 0;
- unsigned int initial_rseq = 0;
- sendpacket_t *sp;
- unsigned int seed = 0;
- /*g for Global header pointers used in pcap_loop callback*/
- tcp_hdr *tcphdr_rprev = NULL;
- unsigned int size_payload_prev = 0;
- unsigned int acked_index = 0;
- unsigned int diff_payload_index = 0;
- bool different_payload = false;
- volatile sig_atomic_t keep_going = 1;
- int random_port();
- unsigned int pkts_scheduled = 0; /* packet counter */
- struct tcp_sched *sched = NULL;
- void got_packet(u_char *args, const struct pcap_pkthdr *header, const u_char *packet);
- void catch_alarm(int sig);
- int iface_addrs(char *iface, input_addr *ip, struct mac_addr *mac);
- int extmac(char *new_rmac_ptr, struct mac_addr *new_remotemac);
- int extip(char *ip_string, input_addr *new_remoteip);
- int rewrite(input_addr *new_remoteip,
- struct mac_addr *new_remotemac,
- input_addr *myip,
- struct mac_addr *mymac,
- char *file,
- unsigned int new_src_port);
- int setup_sched(struct tcp_sched *schedule);
- int relative_sched(struct tcp_sched *schedule, u_int32_t first_rseq, int num_packets);
- int fix_all_checksum_liveplay(ipv4_hdr *iphdr);
- int compip(input_addr *lip, input_addr *rip, input_addr *pkgip);
- int do_checksum_liveplay(u_int8_t *data, int proto, int len);
- int do_checksum_math_liveplay(u_int16_t *data, int len);
- /**
- * This is the main function of the program that handles calling other
- * functions to implemented the needed operations of the replay functionaily.
- */
- int
- main(int argc, char **argv)
- {
- unsigned int k;
- int num_packets;
- static const char random_strg[] = "random";
- char *iface = argv[1];
- char *new_rmac_ptr;
- char *new_rip_ptr;
- input_addr new_remoteip;
- struct mac_addr new_remotemac;
- input_addr myip;
- struct mac_addr mymac;
- int new_src_port;
- unsigned int retransmissions = 0;
- pcap_t *local_handle;
- char errbuf[PCAP_ERRBUF_SIZE];
- char ebuf[SENDPACKET_ERRBUF_SIZE];
- int i;
- optionProcess(&tcpliveplayOptions, argc, argv); /*Process AutoOpts for manpage options*/
- if ((argc < 5) || (argv[1] == NULL) || (argv[2] == NULL) || (argv[3] == NULL) || (argv[4] == NULL) ||
- (argv[5] == NULL)) {
- printf("ERROR: Incorrect Usage!\n");
- printf("Usage: tcpliveplay <eth0/eth1> <file.pcap> <Destination IP [1.2.3.4]> <Destination mac [0a:1b:2c:3d:4e:5f]> <specify 'random' or specific port#>\n");
- printf("Example:\n yhsiam@yhsiam-VirtualBox:~$ sudo tcpliveplay eth0 test1.pcap 192.168.1.4 52:57:01:11:31:92 random\n\n");
- exit(0);
- }
- if (strlen(iface) > IFNAMSIZ - 1)
- errx(-1, "Invalid interface name %s\n", iface);
- if (iface_addrs(iface, &myip, &mymac) < 0) /* Extract MAC of interface replay is being request on */
- errx(-1, "Failed to access interface %s\n", iface);
- /* open send function socket*/
- if ((sp = sendpacket_open(iface, ebuf, TCPR_DIR_C2S, SP_TYPE_NONE, NULL)) == NULL)
- errx(-1, "Can't open %s: %s", argv[1], ebuf);
- /*for(int i = 0; i<10; i++) tolower(port_mode[i]);*/
- if (strcmp(argv[5], random_strg) == 0)
- new_src_port = random_port();
- else
- new_src_port = strtol(argv[5], NULL, 10);
- if (new_src_port < 0 || new_src_port > 65535)
- errx(new_src_port, "Cannot use source port %d", new_src_port);
- printf("new source port:: %d\n", new_src_port);
- /* Establish a handler for SIGALRM signals. */
- /* This is used as timeout for unresponsive remote hosts */
- signal(SIGALRM, catch_alarm);
- /* Extract new Remote MAC & IP inputed at command line */
- new_rmac_ptr = argv[4];
- new_rip_ptr = argv[3];
- /* These function setup the MAC & IP addresses in the mac_addr & in_addr structs */
- if (extmac(new_rmac_ptr, &new_remotemac) == ERROR)
- errx(-1, "failed to parse mac address %s\n", new_rmac_ptr);
- if (extip(new_rip_ptr, &new_remoteip) == ERROR)
- errx(-1, "failed to parse IP address %s\n", new_rip_ptr);
- /* Rewrites the given "*.pcap" file with all the new parameters and returns the number of packets */
- /* that need to be replayed */
- num_packets = rewrite(&new_remoteip, &new_remotemac, &myip, &mymac, argv[2], new_src_port);
- if (num_packets < 2)
- errx(-1, "Unable to rewrite PCAP file %s\n", argv[2]);
- /* create schedule & set it up */
- sched = (struct tcp_sched *)malloc(num_packets * sizeof(struct tcp_sched));
- if (!sched)
- err(-1, "out of memory\n");
- pkts_scheduled = setup_sched(sched); /* Returns number of packets in schedule*/
- /* Set up the schedule struct to be relative numbers rather than absolute*/
- for (i = 0; i < num_packets; i++) {
- sched[i].exp_rseq = 0;
- sched[i].exp_rack = 0;
- }
- relative_sched(sched, sched[1].exp_rseq, num_packets);
- printf("Packets Scheduled %u\n", pkts_scheduled);
- /* Open socket for savedfile traffic to be sent*/
- local_handle = pcap_open_offline("newfile.pcap", errbuf); /*call pcap library function*/
- if (local_handle == NULL) {
- fprintf(stderr, "Couldn't open pcap file %s: %s\n", "newfile.pcap", errbuf);
- free(sched);
- return (2);
- }
- /* Open socket for live traffic to be listed to*/
- live_handle =
- set_live_filter(iface, &myip, new_src_port); /* returns a pcap_t that filters out traffic other than TCP*/
- if (live_handle == NULL) {
- fprintf(stderr, "Error occurred while listing on traffic: %s\n", errbuf);
- free(sched);
- return (2);
- }
- /* Printout when no packets are scheduled */
- if (pkts_scheduled == 0) {
- printf("\n+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++\n");
- printf("+ ERROR:: There are no TCP packets to send +\n");
- printf("+ Closing replay... +\n");
- printf("+ Thank you for Playing, Play again! +\n");
- printf("+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++\n\n");
- free(sched);
- return ERROR;
- }
- /* Start replay by sending the first packet, the SYN, from the schedule */
- else if (sched[0].local) { /* Send first packet*/
- sendpacket(sp, sched[sched_index].packet_ptr, sched[sched_index].pkthdr.len, &sched[sched_index].pkthdr);
- printf("Sending Local Packet............... [%u]\n", sched_index + 1);
- sched_index++; /* Proceed in the schedule */
- }
- /* Main while loop that handles the decision making and the replay oprations */
- while (sched_index < pkts_scheduled) {
- if (!keep_going) { /*Check the timeout variable */
- printf("\n======================================================================\n");
- printf("= TIMEOUT:: Remote host is not responding. You may have crashed =\n");
- printf("= the host you replayed these packets against OR the packet sequence =\n");
- printf("= changed since the capture was taken resulting in differing =\n");
- printf("= expectations. Closing replay... =\n");
- printf("======================================================================\n\n");
- break;
- }
- /* tcphdr_rprev carries the last remote tcp header */
- if (tcphdr_rprev == NULL) {
- // printf("FIRST PASS!\n");
- }
- /* Check if received RST or RST-ACK flagged packets*/
- else if ((tcphdr_rprev->th_flags == TH_RST) || (tcphdr_rprev->th_flags == (TH_RST | TH_ACK))) {
- printf("\n++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++\n");
- printf("+ ERROR:: Remote host has requested to RESET the connection. +\n");
- printf("+ Closing replay... +\n");
- printf("++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++\n\n");
- break;
- }
- /* Do the following if we receive a packet that ACKs for the same ACKing of next packet */
- else if ((tcphdr_rprev->th_seq == htonl(sched[sched_index].exp_rseq)) &&
- (tcphdr_rprev->th_ack == htonl(sched[sched_index].exp_rack)) && (size_payload_prev > 0)) {
- printf("Received Remote Packet............... [%u]\n", sched_index + 1);
- printf("Skipping Packet...................... [%u] to Packet [%u]\n",
- sched_index + 1,
- sched_index + 2);
- printf("Next Remote Packet Expectation met.\nProceeding in replay...\n");
- sched_index++;
- }
- /* Do the following if payload does not meet expectation and re-attempt with the remote host for 3 tries*/
- else if (different_payload) {
- printf("\n+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++\n");
- printf("+ WARNING: Remote host is not meeting packet size expectations. +\n");
- printf("+ for packet %-u. Application layer data differs from capture being replayed. +\n",
- diff_payload_index + 1);
- printf("+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++\n\n");
- printf("Requesting retransmission.\n Proceeding...\n");
- different_payload = false;
- }
- /* Local Packets */
- if (sched[sched_index].local) {
- /*Reset alarm timeout*/
- alarm(ALARM_TIMEOUT);
- printf("Sending Local Packet............... [%u]\n", sched_index + 1);
- /* edit each packet tcphdr before sending based on the schedule*/
- if (sched_index > 0) {
- sched[sched_index].tcphdr->th_ack = htonl(sched[sched_index].curr_lack);
- fix_all_checksum_liveplay(sched[sched_index].iphdr);
- }
- /* If 3 attempts of resending was made, then error out to the user */
- if (sched[sched_index].sent_counter == 3) {
- printf("\n++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++\n");
- printf("+ ERROR: Re-sent packet [%-u] 3 times, but remote host is not +\n", sched_index + 1);
- printf("+ responding as expected. 3 resend attempts are a maximum. +\n");
- printf("+ Closing replay... +\n");
- printf("++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++\n\n");
- break;
- }
- /* If nothing goes wrong, then send the packet scheduled to be sent, then proceed in the schedule */
- sendpacket(sp, sched[sched_index].packet_ptr, sched[sched_index].pkthdr.len, &sched[sched_index].pkthdr);
- sched[sched_index].sent_counter++; /* Keep track of how many times this specific packet was attempted */
- sched_index++; /* proceed */
- }
- /* Remote Packets */
- else if (sched[sched_index].remote) {
- alarm(ALARM_TIMEOUT);
- printf("Receiving Packets from remote host...\n");
- pcap_dispatch(live_handle, 1, got_packet, NULL); /* Listen in on NIC for tcp packets */
- // printf("pcap_loop returned\n");
- }
- } /* end of main while loop*/
- pcap_breakloop(live_handle);
- pcap_close(live_handle);
- sendpacket_close(sp); /* Close Send socket*/
- remove("newfile.pcap"); /* Remote the rewritten file that was created*/
- for (k = 0; k < pkts_scheduled; k++) {
- retransmissions += sched[k].sent_counter;
- }
- /* User Debug Result Printouts*/
- if (sched_index == pkts_scheduled) {
- printf("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n");
- printf("~ CONGRATS!!! You have successfully Replayed your pcap file '%s'\n", argv[2]);
- printf("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n\n");
- } else {
- printf("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n");
- printf("~ Unfortunately an error has occurred halting the replay of\n");
- printf("~ the pcap file '%s'. Please see error above for details...\n", argv[2]);
- printf("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n\n");
- }
- printf("----------------TCP Live Play Summary----------------\n");
- printf("- Packets Scheduled to be Sent & Received: %-u\n", pkts_scheduled);
- printf("- Actual Packets Sent & Received: %-u\n", sched_index);
- printf("- Total Local Packet Re-Transmissions due to packet\n");
- printf("- loss and/or differing payload size than expected: %-u\n", retransmissions);
- printf("- Thank you for Playing, Play again!\n");
- printf("----------------------------------------------------------\n\n");
- free(sched);
- restore_stdin();
- return 0;
- }
- /*end of main() function*/
- /**
- * This function serves as a timer alarm
- */
- void
- catch_alarm(int sig)
- {
- keep_going = 0;
- signal(sig, catch_alarm);
- }
- static int
- tcplp_rand(void)
- {
- struct timeval tv;
- if (!seed) {
- gettimeofday(&tv, NULL);
- seed = (unsigned int)tv.tv_sec ^ (unsigned int)tv.tv_usec;
- }
- return (int)tcpr_random(&seed);
- }
- /**
- * This function returns a random number between 49152 and 65535
- */
- int
- random_port()
- {
- int random = tcplp_rand();
- return (49152 + (random % 16383));
- }
- /**
- * This function sets up the scheduled local ACK and Remote SEQ to be relative numbers,
- * While it sets up the local SEQs and remote ACKs to be absolute within the schedule.
- */
- int
- relative_sched(struct tcp_sched *schedule, u_int32_t first_rseq, int num_packets)
- {
- int i;
- u_int32_t lseq_adjust = tcplp_rand();
- printf("Random Local SEQ: %u\n", lseq_adjust);
- u_int32_t first_lseq = schedule[0].curr_lseq; /* SYN Packet SEQ number */
- /* Fix schedule to relative and absolute */
- for (i = 0; i < num_packets; i++) {
- if (schedule[i].local) {
- schedule[i].curr_lseq = schedule[i].curr_lseq - first_lseq; /* Fix current local SEQ to relative */
- schedule[i].curr_lseq = schedule[i].curr_lseq +
- lseq_adjust; /* Make absolute. lseq_adjust is the locally generated random number */
- schedule[i].curr_lack = schedule[i].curr_lack - first_rseq; /* Fix current local ACK to relative */
- if (schedule[i].tcphdr)
- schedule[i].tcphdr->th_seq = htonl(schedule[i].curr_lseq); /* Edit the actual packet header data */
- fix_all_checksum_liveplay(schedule[i].iphdr); /* Fix the checksum */
- schedule[i].exp_rseq = schedule[i].exp_rseq - first_rseq;
- schedule[i].exp_rack = schedule[i].exp_rack - first_lseq;
- schedule[i].exp_rack = schedule[i].exp_rack + lseq_adjust;
- } else if (schedule[i].remote) {
- schedule[i].exp_rseq = schedule[i].exp_rseq - first_rseq; /* Fix expected remote SEQ to be relative */
- schedule[i].exp_rack = schedule[i].exp_rack - first_lseq; /* Fix expected remote ACK to be relative*/
- schedule[i].exp_rack = schedule[i].exp_rack + lseq_adjust; /* Fix expected remote ACK to be absolute */
- }
- }
- return SUCCESS;
- }
- /**
- * This function sets up the schedule for the rest of the program
- * extracting all the needed information from the given pcap file
- * and coping into memory (into a struct format)
- *
- */
- int
- setup_sched(struct tcp_sched *schedule)
- {
- input_addr sip, dip; /* Source & Destination IP */
- input_addr local_ip, remote_ip; /* ip address of client and server*/
- pcap_t *local_handle;
- const u_char *packet; /* The actual packet */
- unsigned int flags;
- struct pcap_pkthdr header; // The header that pcap gives us
- int pkt_counter = 0;
- bool remote = false; /* flags to test if data is from 'client'=local or 'server'=remote */
- bool local = false;
- unsigned int i = 0;
- local_ip.byte1 = 0;
- local_ip.byte2 = 0;
- local_ip.byte3 = 0;
- local_ip.byte4 = 0;
- remote_ip.byte1 = 0;
- remote_ip.byte2 = 0;
- remote_ip.byte3 = 0;
- remote_ip.byte4 = 0;
- char errbuf[PCAP_ERRBUF_SIZE];
- local_handle = pcap_open_offline("newfile.pcap", errbuf); /*call pcap library function*/
- if (local_handle == NULL) {
- fprintf(stderr, "Couldn't open pcap file %s: %s\n", "newfile.pcap", errbuf);
- return (2);
- }
- /*Before sending any packet, setup the schedule with the proper parameters*/
- while ((packet = safe_pcap_next(local_handle, &header))) {
- /*temporary packet buffers*/
- ether_hdr *etherhdr;
- tcp_hdr *tcphdr;
- ipv4_hdr *iphdr;
- unsigned int size_ip;
- unsigned int size_tcp;
- unsigned int size_payload;
- pkt_counter++; /*increment number of packets seen*/
- memcpy(&schedule[i].pkthdr, &header, sizeof(struct pcap_pkthdr));
- schedule[i].packet_ptr = safe_malloc(schedule[i].pkthdr.len);
- memcpy(schedule[i].packet_ptr, packet, schedule[i].pkthdr.len);
- /* extract necessary data */
- etherhdr = (ether_hdr *)(schedule[i].packet_ptr);
- iphdr = (ipv4_hdr *)(schedule[i].packet_ptr + SIZE_ETHERNET);
- size_ip = iphdr->ip_hl << 2;
- if (size_ip < 20) {
- printf("ERROR: Invalid IP header length: %u bytes\n", size_ip);
- return 0;
- }
- tcphdr = (tcp_hdr *)(schedule[i].packet_ptr + SIZE_ETHERNET + size_ip);
- size_tcp = tcphdr->th_off * 4;
- if (size_tcp < 20) {
- printf("ERROR: Invalid TCP header length: %u bytes\n", size_tcp);
- return 0;
- }
- /* payload = (u_char *)(schedule[i].packet_ptr + SIZE_ETHERNET + size_ip + size_tcp); */
- size_payload = ntohs(iphdr->ip_len) - (size_ip + (size_tcp));
- /* Source IP and Destination IP */
- sip = iphdr->ip_src;
- dip = iphdr->ip_dst;
- flags = tcphdr->th_flags;
- if (flags == TH_SYN) { /* set IPs who's local and who's remote based on the SYN flag */
- local_ip = sip;
- remote_ip = dip;
- }
- /*Compare IPs to see which packet is this coming from*/
- if (compip(&local_ip, &remote_ip, &sip) == LOCAL_IP_MATCH) {
- local = true;
- remote = false;
- }
- if (compip(&local_ip, &remote_ip, &sip) == REMOTE_IP_MATCH) {
- local = false;
- remote = true;
- }
- /* Setup rest of Schedule, parameter by parameter */
- /* Refer to header file for details on each of the parameters */
- schedule[i].etherhdr = etherhdr;
- schedule[i].iphdr = iphdr;
- schedule[i].tcphdr = tcphdr;
- schedule[i].size_ip = size_ip;
- schedule[i].size_tcp = size_tcp;
- schedule[i].size_payload = size_payload;
- schedule[i].sent_counter = 0;
- /* Do the following only for the first packet (SYN)*/
- if (i == 0) {
- schedule[i].length_last_ldata = 0;
- schedule[i].length_curr_ldata = 0;
- schedule[i].length_last_rdata = 0;
- schedule[i].length_curr_rdata = 0;
- schedule[i].local = true;
- schedule[i].remote = false;
- schedule[i].curr_lseq = ntohl(schedule[i].tcphdr->th_seq);
- schedule[i].curr_lack = 0;
- schedule[i].exp_rseq = 0; /* Keep track of previous remote seq & ack #s*/
- schedule[i].exp_rack = 0;
- }
- /* Local Packet operations */
- else if (local) {
- schedule[i].length_last_ldata = schedule[i - 1].length_curr_ldata;
- schedule[i].length_curr_ldata = size_payload;
- schedule[i].length_last_rdata = schedule[i - 1].length_curr_rdata;
- schedule[i].length_curr_rdata = 0;
- schedule[i].local = true;
- schedule[i].remote = false;
- schedule[i].curr_lseq = ntohl(schedule[i].tcphdr->th_seq);
- schedule[i].curr_lack = ntohl(schedule[i].tcphdr->th_ack);
- schedule[i].exp_rseq = schedule[i - 1].exp_rseq; /* Keep track of previous remote seq & ack #s*/
- schedule[i].exp_rack = schedule[i - 1].exp_rack;
- }
- /* Remote Packet operations */
- else if (remote) {
- schedule[i].length_last_ldata = schedule[i - 1].length_curr_ldata;
- schedule[i].length_curr_ldata = 0;
- schedule[i].length_last_rdata = schedule[i - 1].length_curr_rdata;
- schedule[i].length_curr_rdata = size_payload;
- schedule[i].local = false;
- schedule[i].remote = true;
- schedule[i].curr_lseq = schedule[i - 1].curr_lseq;
- schedule[i].curr_lack = schedule[i - 1].curr_lack;
- schedule[i].exp_rseq = ntohl(schedule[i].tcphdr->th_seq); /* Keep track of previous remote seq & ack #s*/
- schedule[i].exp_rack = ntohl(schedule[i].tcphdr->th_ack);
- }
- i++; /* increment schedule index */
- } /*end internal loop for reading packets (all in one file)*/
- pcap_close(local_handle); /*close the pcap file*/
- return pkt_counter; /* Return number of packets scheduled */
- }
- /**
- * This function returns a pcap_t for the live traffic handler which
- * filters out traffic other than TCP
- *
- */
- pcap_t *
- set_live_filter(char *dev, input_addr *hostip, unsigned int port)
- {
- pcap_t *handle = NULL; /* Session handle */
- char errbuf[PCAP_ERRBUF_SIZE]; /* Error string buffer */
- struct bpf_program fp; /* The compiled filter */
- char filter_exp[52];
- sprintf(filter_exp,
- "tcp and dst host %d.%d.%d.%d and dst port %u",
- hostip->byte1,
- hostip->byte2,
- hostip->byte3,
- hostip->byte4,
- port); /* The filter expression */
- bpf_u_int32 mask; /* Our network mask */
- bpf_u_int32 net; /* Our IP */
- /* Define the device */
- if (dev == NULL) {
- fprintf(stderr, "Couldn't find default device: %s\n", errbuf);
- return handle;
- }
- /* Find the properties for the device */
- if (pcap_lookupnet(dev, &net, &mask, errbuf) == -1) {
- fprintf(stderr, "Couldn't get netmask for device %s: %s\n", dev, errbuf);
- net = 0;
- mask = 0;
- }
- /* Open the session in promiscuous mode */
- handle = pcap_open_live(dev, BUFSIZ_PLUS, PROMISC_OFF, TIMEOUT_ms, errbuf);
- if (handle == NULL) {
- fprintf(stderr, "Couldn't open device %s: %s\n", dev, errbuf);
- return handle;
- }
- /* Compile and apply the filter */
- if (pcap_compile(handle, &fp, filter_exp, 0, net) == -1) {
- fprintf(stderr, "Couldn't parse filter %s: %s\n", filter_exp, pcap_geterr(handle));
- return handle;
- }
- if (pcap_setfilter(handle, &fp) == -1) {
- fprintf(stderr, "Couldn't install filter %s: %s\n", filter_exp, pcap_geterr(handle));
- return handle;
- }
- pcap_freecode(&fp);
- return handle;
- }
- /**
- * This function returns a pcap_t for the savedfile traffic handler which
- * filters out traffic other than TCP
- *
- */
- pcap_t *
- set_offline_filter(char *file)
- {
- pcap_t *handle; /* Session handle */
- char errbuf[PCAP_ERRBUF_SIZE]; /* Error string */
- struct bpf_program fp; /* The compiled filter */
- char filter_exp[] = "tcp";
- bpf_u_int32 net = 0; /* Our IP */
- /* Open savedfile */
- handle = pcap_open_offline(file, errbuf);
- if (handle == NULL) {
- fprintf(stderr, "Couldn't open file %s\n", errbuf);
- return handle;
- }
- /* Compile and apply the filter */
- if (pcap_compile(handle, &fp, filter_exp, 0, net) == -1) {
- fprintf(stderr, "Couldn't parse filter %s: %s\n", filter_exp, pcap_geterr(handle));
- return handle;
- }
- if (pcap_setfilter(handle, &fp) == -1) {
- fprintf(stderr, "Couldn't install filter %s: %s\n", filter_exp, pcap_geterr(handle));
- return handle;
- }
- pcap_freecode(&fp);
- return handle;
- }
- /**
- * This is the callback function for pcap_loop
- * This function is called every time we receive a remote packet
- */
- void
- got_packet(_U_ u_char *args, _U_ const struct pcap_pkthdr *header, const u_char *packet)
- {
- tcp_hdr *tcphdr;
- ipv4_hdr *iphdr;
- unsigned int size_ip, size_tcp, size_payload;
- unsigned int flags;
- /* Extract and examine received packet headers */
- iphdr = (ipv4_hdr *)(packet + SIZE_ETHERNET);
- size_ip = iphdr->ip_hl << 2;
- if (size_ip < 20) {
- printf("ERROR: Invalid IP header length: %u bytes\n", size_ip);
- return;
- }
- tcphdr = (tcp_hdr *)(packet + SIZE_ETHERNET + size_ip);
- size_tcp = tcphdr->th_off * 4;
- if (size_tcp < 20) {
- printf("ERROR: Invalid TCP header length: %u bytes\n", size_tcp);
- return;
- }
- size_payload = ntohs(iphdr->ip_len) - (size_ip + (size_tcp));
- flags = tcphdr->th_flags;
- /* Check correct SYN-ACK expectation, if so then proceed in fixing entire schedule from relative to absolute
- * SEQs+ACKs */
- if ((flags == (TH_SYN | TH_ACK)) && (sched_index == 1) &&
- (tcphdr->th_ack == htonl(sched[sched_index - 1].curr_lseq + 1))) {
- unsigned int j;
- printf("Received Remote Packet............... [%u]\n", sched_index + 1);
- printf("Remote Packet Expectation met.\nProceeding in replay....\n");
- // printf("SYN-ACKed Random SEQ set!\n");
- initial_rseq = ntohl(tcphdr->th_seq);
- // printf("initial_rseq: %u\n", initial_rseq);
- /* After we receiving the first SYN-ACK, then adjust the entire sched to be absolute rather than relative #s*/
- sched[1].exp_rseq = sched[1].exp_rseq + initial_rseq;
- for (j = 2; j < pkts_scheduled;
- j++) { /* Based on correctly receiving the random SEQ from the SYN-ACK packet, do the following:*/
- if (sched[j].local) { /* Set local ACKs for entire sched to be absolute #s*/
- sched[j].curr_lack = sched[j].curr_lack + initial_rseq;
- } else if (sched[j].remote) { /* Set remote SEQs for entire sched to be absolute #s*/
- sched[j].exp_rseq = sched[j].exp_rseq + initial_rseq;
- }
- }
- sched_index++; /* Proceed in the schedule*/
- return;
- }
- printf(">Received a Remote Packet\n");
- printf(">>Checking Expectations\n");
- /* Handle Remote Packet Loss */
- if (sched[sched_index].exp_rack > ntohl(tcphdr->th_ack)) {
- // printf("Remote Packet Loss! Resending Lost packet\n");
- sched_index = acked_index; /* Reset the schedule index back to the last correctly ACKed packet */
- // printf("ACKED Index = %d\n", acked_index);
- while (!sched[sched_index].local) {
- sched_index++;
- }
- return;
- }
- /* Handle Local Packet Loss <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<COME BACK TO
- THIS<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< */
- else if ((sched[sched_index].exp_rseq < ntohl(tcphdr->th_seq)) && sched[sched_index].remote) {
- /* Resend immediate previous LOCAL packet */
- printf("Local Packet Loss! Resending Lost packet >> DupACK Issued!\n");
- sched_index = acked_index; /* Reset the schedule index back to the last correctly ACKed packet */
- /*sched[sched_index].sent_counter=0; Reset the re-transmission counter for this ACKed packet?*/
- // printf("ACKED Index = %d\n", acked_index);
- while (!sched[sched_index].local) {
- sched_index++;
- }
- return;
- }
- /* No Packet Loss... Proceed Normally (if expectations are met!) */
- else if ((tcphdr->th_seq == htonl(sched[sched_index].exp_rseq)) &&
- (tcphdr->th_ack == htonl(sched[sched_index].exp_rack))) {
- printf("Received Remote Packet............... [%d]\n", sched_index + 1);
- /* Handles differing payload size and does not trigger on unnecessary ACK + window update issues*/
- if ((sched[sched_index].size_payload != size_payload) && (size_payload != 0)) {
- printf("Payload size of received packet does not meet expectations\n");
- /* Resent last local packet, maybe remote host behaves this time*/
- different_payload = true;
- /* Set global variable of where differing payload size is not meeting expectations*/
- diff_payload_index = sched_index;
- /*Treat this as packet loss, and attempt resetting index to resend packets where*/
- /* packets were received matching expectation*/
- sched_index = acked_index; /* Reset the schedule index back to the last correctly ACKed packet */
- // printf("ACKED Index = %d\n", acked_index);
- while (!sched[sched_index].local) {
- sched_index++;
- }
- return;
- }
- printf("Remote Packet Expectation met.\nProceeding in replay....\n");
- sched_index++;
- acked_index = sched_index; /*Keep track correctly ACKed packet index*/
- }
- /* Global variable to keep tack of last received packet info */
- tcphdr_rprev = tcphdr;
- size_payload_prev = size_payload;
- }
- /**
- * This function compares two IPs,
- * returns 1 if match with local ip
- * returns 2 if matches with remote ip
- * returns 0 if no match
- *
- */
- int
- compip(input_addr *lip, input_addr *rip, input_addr *pkgip)
- {
- if ((lip->byte1 == pkgip->byte1) && (lip->byte2 == pkgip->byte2) && (lip->byte3 == pkgip->byte3) &&
- (lip->byte4 == pkgip->byte4))
- return LOCAL_IP_MATCH;
- else if ((rip->byte1 == pkgip->byte1) && (rip->byte2 == pkgip->byte2) && (rip->byte3 == pkgip->byte3) &&
- (rip->byte4 == pkgip->byte4))
- return REMOTE_IP_MATCH;
- else
- return NO_MATCH;
- }
- /**
- * This function sets the IP and MAC of a given interface (i.e. eth0)
- * into in_addr & mac_addr struct pointers
- *
- */
- int
- iface_addrs(char *iface, input_addr *ip, struct mac_addr *mac)
- {
- int s;
- struct ifreq buffer;
- s = socket(PF_INET, SOCK_DGRAM, 0);
- if (s < 0)
- return -1;
- memset(&buffer, 0x00, sizeof(buffer));
- strncpy(buffer.ifr_name, iface, sizeof(buffer.ifr_name) - 1);
- int res;
- if ((res = ioctl(s, SIOCGIFADDR, &buffer)) < 0)
- goto done;
- struct in_addr localip = ((struct sockaddr_in *)&buffer.ifr_addr)->sin_addr;
- #if defined(WORDS_BIGENDIAN)
- ip->byte1 = (localip.s_addr) >> 24;
- ip->byte2 = ((localip.s_addr) >> 16) & 255;
- ip->byte3 = ((localip.s_addr) >> 8) & 255;
- ip->byte4 = (localip.s_addr) & 255;
- #else
- ip->byte4 = (localip.s_addr) >> 24;
- ip->byte3 = ((localip.s_addr) >> 16) & 255;
- ip->byte2 = ((localip.s_addr) >> 8) & 255;
- ip->byte1 = (localip.s_addr) & 255;
- #endif
- if ((res = ioctl(s, SIOCGIFHWADDR, &buffer)) < 0)
- goto done;
- mac->byte1 = buffer.ifr_hwaddr.sa_data[0];
- mac->byte2 = buffer.ifr_hwaddr.sa_data[1];
- mac->byte3 = buffer.ifr_hwaddr.sa_data[2];
- mac->byte4 = buffer.ifr_hwaddr.sa_data[3];
- mac->byte5 = buffer.ifr_hwaddr.sa_data[4];
- mac->byte6 = buffer.ifr_hwaddr.sa_data[5];
- done:
- close(s);
- return res;
- }
- /**
- * This function rewrites the IPs and MACs of a given packet,
- * creates a newfile.pcap. It returns the number of packets of the newfile.
- * This function only starts rewriting the newfile once it sees the first
- * SYN packet. This is so that the first packet in the newfile is always
- * the first packet to be sent.
- */
- int
- rewrite(input_addr *new_remoteip,
- struct mac_addr *new_remotemac,
- input_addr *myip,
- struct mac_addr *mymac,
- char *file,
- unsigned int new_src_port)
- {
- char *newfile = "newfile.pcap";
- input_addr local_ip;
- input_addr remote_ip;
- const u_char *packet;
- struct pcap_pkthdr *header;
- pcap_dumper_t *dumpfile;
- input_addr sip; /* Source IP */
- int local_packets = 0;
- bool initstep1 = false; /* keep track of successful handshake step */
- bool warned = false;
- local_ip.byte1 = 0;
- local_ip.byte2 = 0;
- local_ip.byte3 = 0;
- local_ip.byte4 = 0;
- remote_ip.byte1 = 0;
- remote_ip.byte2 = 0;
- remote_ip.byte3 = 0;
- remote_ip.byte4 = 0;
- pcap_t *pcap = set_offline_filter(file);
- if (!pcap) {
- char ErrBuff[1024];
- fprintf(stderr, "Cannot open PCAP file '%s' for reading\n", file);
- fprintf(stderr, "%s\n", ErrBuff);
- return PCAP_OPEN_ERROR;
- }
- dumpfile = pcap_dump_open(pcap, newfile);
- if (!dumpfile) {
- fprintf(stderr, "Cannot open PCAP file '%s' for writing\n", newfile);
- return PCAP_OPEN_ERROR;
- }
- /*Modify each packet's IP & MAC based on the passed args then do a checksum of each packet*/
- while (safe_pcap_next_ex(pcap, &header, &packet) > 0) {
- unsigned int flags, size_ip;
- ether_hdr *etherhdr;
- ipv4_hdr *iphdr;
- tcp_hdr *tcphdr;
- unsigned int size_tcp;
- if (!warned && header->len > header->caplen) {
- fprintf(stderr, "warning: packet capture truncated to %d byte packets\n", header->caplen);
- warned = true;
- }
- etherhdr = (ether_hdr *)(packet);
- iphdr = (ipv4_hdr *)(packet + SIZE_ETHERNET);
- size_ip = iphdr->ip_hl << 2;
- if (size_ip < 20) {
- printf("ERROR: Invalid IP header length: %u bytes\n", size_ip);
- return ERROR;
- }
- tcphdr = (tcp_hdr *)(packet + SIZE_ETHERNET + size_ip);
- size_tcp = tcphdr->th_off * 4;
- if (size_tcp < 20) {
- printf("ERROR: Invalid TCP header length: %u bytes\n", size_tcp);
- return ERROR;
- }
- /* payload = (u_char *)(packet + SIZE_ETHERNET + size_ip + size_tcp); */
- sip = iphdr->ip_src;
- flags = tcphdr->th_flags;
- /* set IPs who's local and who's remote based on the SYN flag */
- if (flags == TH_SYN) {
- local_ip = iphdr->ip_src;
- remote_ip = iphdr->ip_dst;
- initstep1 = true; /* This flag is set to signify the first encounter of the SYN within the pacp*/
- }
- if (compip(&local_ip, &remote_ip, &sip) == LOCAL_IP_MATCH) {
- /* Set the source MAC */
- etherhdr->ether_shost[0] = mymac->byte1;
- etherhdr->ether_shost[1] = mymac->byte2;
- etherhdr->ether_shost[2] = mymac->byte3;
- etherhdr->ether_shost[3] = mymac->byte4;
- etherhdr->ether_shost[4] = mymac->byte5;
- etherhdr->ether_shost[5] = mymac->byte6;
- /* Set the source IP */
- iphdr->ip_src = *myip;
- /* Set the destination IP */
- iphdr->ip_dst = *new_remoteip;
- /* Set the destination MAC */
- etherhdr->ether_dhost[0] = new_remotemac->byte1;
- etherhdr->ether_dhost[1] = new_remotemac->byte2;
- etherhdr->ether_dhost[2] = new_remotemac->byte3;
- etherhdr->ether_dhost[3] = new_remotemac->byte4;
- etherhdr->ether_dhost[4] = new_remotemac->byte5;
- etherhdr->ether_dhost[5] = new_remotemac->byte6;
- /* This is to change the source port, whether it is specified as random or as a port # by the user */
- tcphdr->th_sport = htons(new_src_port);
- } else if (compip(&local_ip, &remote_ip, &sip) == REMOTE_IP_MATCH) {
- /* Set the destination MAC */
- etherhdr->ether_dhost[0] = mymac->byte1;
- etherhdr->ether_dhost[1] = mymac->byte2;
- etherhdr->ether_dhost[2] = mymac->byte3;
- etherhdr->ether_dhost[3] = mymac->byte4;
- etherhdr->ether_dhost[4] = mymac->byte5;
- etherhdr->ether_dhost[5] = mymac->byte6;
- /* Set the destination IP */
- iphdr->ip_dst = *myip;
- /* Set the source IP */
- iphdr->ip_src = *new_remoteip;
- /* Set the source MAC */
- etherhdr->ether_shost[0] = new_remotemac->byte1;
- etherhdr->ether_shost[1] = new_remotemac->byte2;
- etherhdr->ether_shost[2] = new_remotemac->byte3;
- etherhdr->ether_shost[3] = new_remotemac->byte4;
- etherhdr->ether_shost[4] = new_remotemac->byte5;
- etherhdr->ether_shost[5] = new_remotemac->byte6;
- /* This is to change the source port, whether it is specified as random or as a port # by the user */
- tcphdr->th_dport = htons(new_src_port);
- }
- /*Calculate & fix checksum for newly edited-packet*/
- fix_all_checksum_liveplay(iphdr);
- if (initstep1) { /*only start rewriting new pcap with SYN packets on wards*/
- local_packets++;
- pcap_dump((u_char *)dumpfile, header, packet);
- }
- } /* end of while loop */
- pcap_close(pcap);
- pcap_dump_close(dumpfile);
- return local_packets;
- }
- /**
- * This function extracts the MAC address (from command line format
- * and sets the mac_addr struct)
- *
- */
- int
- extmac(char *new_rmac_ptr, struct mac_addr *new_remotemac)
- {
- u_int8_t new_rmac[6];
- if (sscanf(new_rmac_ptr,
- "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx",
- &new_rmac[0],
- &new_rmac[1],
- &new_rmac[2],
- &new_rmac[3],
- &new_rmac[4],
- &new_rmac[5]) != 6)
- return ERROR;
- new_remotemac->byte1 = (unsigned char)new_rmac[0];
- new_remotemac->byte2 = (unsigned char)new_rmac[1];
- new_remotemac->byte3 = (unsigned char)new_rmac[2];
- new_remotemac->byte4 = (unsigned char)new_rmac[3];
- new_remotemac->byte5 = (unsigned char)new_rmac[4];
- new_remotemac->byte6 = (unsigned char)new_rmac[5];
- return SUCCESS;
- }
- /**
- * This function extracts the IP address (from command line format
- * and sets the in_addr struct)
- *
- */
- int
- extip(char *ip_string, input_addr *new_remoteip)
- {
- struct in_addr addr;
- if (inet_aton(ip_string, &addr) == 0)
- return ERROR;
- #if defined(WORDS_BIGENDIAN)
- new_remoteip->byte4 = (unsigned char)addr.s_addr & 0xff;
- new_remoteip->byte3 = (unsigned char)(addr.s_addr >> 8) & 0xff;
- new_remoteip->byte2 = (unsigned char)(addr.s_addr >> 16) & 0xff;
- new_remoteip->byte1 = (unsigned char)(addr.s_addr >> 24) & 0xff;
- #else
- new_remoteip->byte1 = (unsigned char)addr.s_addr & 0xff;
- new_remoteip->byte2 = (unsigned char)(addr.s_addr >> 8) & 0xff;
- new_remoteip->byte3 = (unsigned char)(addr.s_addr >> 16) & 0xff;
- new_remoteip->byte4 = (unsigned char)(addr.s_addr >> 24) & 0xff;
- #endif
- return SUCCESS;
- }
- /**
- * This function calls all the checksum function given the IP Header
- * and edits the checksums fixing them appropriately
- *
- */
- int
- fix_all_checksum_liveplay(ipv4_hdr *iphdr)
- {
- int ret;
- /*Calculate TCP Checksum*/
- ret = do_checksum_liveplay((u_char *)iphdr, iphdr->ip_p, ntohs(iphdr->ip_len) - (iphdr->ip_hl << 2));
- if (ret != TCPEDIT_OK) {
- printf("*******An Error Occurred calculating TCP Checksum*******\n");
- return -1;
- }
- /*Calculate IP Checksum*/
- do_checksum_liveplay((u_char *)iphdr, IPPROTO_IP, ntohs(iphdr->ip_len));
- return 0;
- }
- /************************************************************************************/
- /*[copied from Aaron Turnor's checksum.c, but omitting tcpedit_t structs] */
- /*[The following functions have been slightly modified to be integrated with tcpliveplay code structure] */
- /**
- * This code re-calcs the IP and Layer 4 checksums
- * the IMPORTANT THING is that the Layer 4 header
- * is contiguous in memory after *ip_hdr we're actually
- * writing to the layer 4 header via the ip_hdr ptr.
- * (Yes, this sucks, but that's the way libnet works, and
- * I was too lazy to re-invent the wheel.
- * Returns 0 on success, -1 on error
- */
- /**
- * Returns -1 on error and 0 on success, 1 on warn
- */
- int
- do_checksum_liveplay(u_int8_t *data, int proto, int len)
- {
- ipv4_hdr *ipv4;
- tcp_hdr *tcp;
- int ip_hl;
- volatile int sum; // <-- volatile works around a PPC g++ bug
- ipv4 = NULL;
- ipv4 = (ipv4_hdr *)data;
- ip_hl = ipv4->ip_hl << 2;
- switch (proto) {
- case IPPROTO_TCP:
- tcp = (tcp_hdr *)(data + ip_hl);
- #ifdef STUPID_SOLARIS_CHECKSUM_BUG
- tcp->th_sum = tcp->th_off << 2;
- return (TCPEDIT_OK);
- #endif
- tcp->th_sum = 0;
- /* Note, we do both src & dst IP's at the same time, that's why the
- * length is 2x a single IP
- */
- sum = do_checksum_math_liveplay((u_int16_t *)&ipv4->ip_src, 8);
- sum += ntohs(IPPROTO_TCP + len);
- sum += do_checksum_math_liveplay((u_int16_t *)tcp, len);
- tcp->th_sum = CHECKSUM_CARRY(sum);
- break;
- case IPPROTO_IP:
- ipv4->ip_sum = 0;
- sum = do_checksum_math_liveplay((u_int16_t *)data, ip_hl);
- ipv4->ip_sum = CHECKSUM_CARRY(sum);
- break;
- default:
- printf("Unsupported protocol for checksum:\n");
- return TCPEDIT_WARN;
- }
- return TCPEDIT_OK;
- }
- /**
- * code to do a ones-compliment checksum
- */
- int
- do_checksum_math_liveplay(u_int16_t *data, int len)
- {
- int sum = 0;
- union {
- u_int16_t s;
- u_int8_t b[2];
- } pad;
- while (len > 1) {
- sum += *data++;
- len -= 2;
- }
- if (len == 1) {
- pad.b[0] = *(u_int8_t *)data;
- pad.b[1] = 0;
- sum += pad.s;
- }
- return (sum);
- }
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