--- /dev/null
+/* mkcap.c
+ * A small program to generate the ASCII form of a capture with TCP
+ * segments of a reasonable nature. The payload is all zeros.
+ *
+ * $Id: mkcap.c,v 1.1 2003/10/05 05:04:32 sharpe Exp $
+ *
+ * By Ronnie Sahlberg and Richard Sharpe. From a program initially
+ * written by Ronnie.
+ * Copyright 2003 Ronnie Sahlberg and Richard Sharpe
+ *
+ * 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; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Using it to generate a capture file:
+ * ./mkcap [some-flags] > some-file
+ * text2pcap [some-other-flags] some-file some-file.cap
+ * For example:
+
+./mkcap -a 2500 -s 15 -I "02 03 04 05" -i "45 45 45 45" -P "00 14" > ftp.cap.asci
+text2pcap -t "%Y/%m/%d%t%H:%M:%S." ftp.cap.asci ftp.cap
+
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#define ETH_1 "00 00 9c fa 1d 74"
+#define ETH_2 "00 1a b8 93 f6 71"
+#define IP_1 "0a 01 01 17"
+#define IP_2 "0a 01 01 ea"
+#define PORT_1 "01 00"
+#define PORT_2 "10 00"
+
+char *eth_1 = ETH_1;
+char *eth_2 = ETH_2;
+char *ip_1 = IP_1;
+char *ip_2 = IP_2;
+char *port_1 = PORT_1;
+char *port_2 = PORT_2;
+
+int verbose = 0;
+
+typedef enum {
+ normal = 0,
+ random_ack_drop = 1,
+ random_data_drop = 2,
+} run_type_t;
+
+typedef struct {
+ int drop_seg_start;
+ int drop_seg_count;
+} seg_drop_t;
+
+/*
+ * The array of which segments should be dropped ...
+ */
+seg_drop_t *drops = NULL;
+int seg_drop_count = 0;
+/* The array of which ACKs should be dropped. This is complicated because
+ * An ack might not be generated for a segment because of delayed ACKs.
+ */
+seg_drop_t *ack_drops = NULL;
+int ack_drop_count = 0;
+
+int total_bytes = 32768;
+int run_type = 0;
+
+int seq_2=0;
+int seq_1=0;
+int ts=0;
+int jitter = 0;
+int send_spacing = 10;
+int ack_delay = 5000;
+int tcp_nodelay = 0;
+int tcp_delay_time = 1000; /* What is the real time here? */
+/*
+ * If tcp_nodelay is set, then this is the amount of data left ...
+ */
+int remaining_data = 0;
+int snap_len = 1500;
+int window = 32768;
+int ssthresh = 16384;
+int cwnd = 1460;
+int used_win = 0;
+int segment = 0;
+
+#define SEG_ACK_LOST 1
+#define SEG_SEG_LOST 2
+
+struct seg_hist_s {
+ int seq_num; /* First sequence number in segment */
+ int len; /* Number of bytes in segment */
+ int ts; /* Timestamp when sent */
+ int seg_num; /* Segment number sent. This can change */
+ /* but a retransmit will have a new seg */
+ int flags; /* Flags as above for ack and seg loss */
+ int acks_first_seq; /* How many times we have seen an ack
+ for the first seq number in this seg */
+};
+
+#define SEG_HIST_SIZE 128
+struct seg_hist_s seg_hist[128]; /* This should be dynamic */
+int next_slot = 0;
+int first_slot = 0;
+
+int delayed_ack = 1; /* Default is delayed ACKs in use ... */
+int delayed_ack_wait = 30000; /* 30 mS before an ACK is generated if */
+ /* no other traffic */
+
+void
+makeseg(char *eth1, char *eth2, char *ip1, char *ip2, char *p1, char *p2, int *s1, int *s2, char *flags, int len)
+{
+ int i;
+
+ printf("2002/01/07 00:00:%02d.%06d\n", ts/1000000, ts%1000000);
+ printf("0000 %s %s 08 00\n", eth1, eth2);
+ printf("000e 45 00 %02x %02x 00 00 00 00 40 06 00 00 %s %s\n", (len+40)>>8, (len+40)&0xff, ip1, ip2);
+ printf("0022 %s %s %02x %02x %02x %02x %02x %02x %02x %02x 50 %s 80 00 00 00 00 00", p1, p2,
+ ((*s1)>>24)&0xff,
+ ((*s1)>>16)&0xff,
+ ((*s1)>>8)&0xff,
+ ((*s1))&0xff,
+ ((*s2)>>24)&0xff,
+ ((*s2)>>16)&0xff,
+ ((*s2)>>8)&0xff,
+ ((*s2))&0xff,
+ flags );
+ for(i=0;i<(len<(snap_len-40)?len:snap_len-40);i++)printf(" 00");
+ printf("\n");
+ printf("\n");
+ (*s1)+=len;
+}
+
+/*
+ * Figure out when the next ack is due ... here we must skip the acks for
+ * frames that are marked as ACKs dropped as well as the frames marked as
+ * frames dropped. These will be marked by the routine that generates ACKs.
+ * Returns a timestamp value. Returns 2^^31-1 if none are due at all
+ */
+int next_ack_due()
+{
+ int slot = next_slot;
+ int ack_lost = 0, seg_lost = 0;
+
+ if (next_slot == first_slot)
+ return (((unsigned int)(1<<31)) - 1);
+
+ /*
+ * Figure out if we need to issue an ACK. We skip all outstanding packets
+ * that are marked as ack lost or packet lost.
+ *
+ * We would not usually come in here with a frame marked as lost or ack lost
+ * rather, we will come in here and specify that the ack was due at a
+ * certain time, and gen_next_ack would then determine that the ack
+ * should be lost or the packet lost.
+ */
+
+ /*
+ * Look for a seg slot that is not lost or dropped
+ */
+
+ while (seg_hist[slot].flags & (SEG_ACK_LOST || SEG_SEG_LOST)) {
+ if (seg_hist[slot].flags & SEG_ACK_LOST)
+ ack_lost++;
+ if (seg_hist[slot].flags & SEG_SEG_LOST)
+ seg_lost++;
+ slot = (slot + 1) % SEG_HIST_SIZE;
+ }
+
+ if (slot == next_slot)
+ return (((unsigned int)(1<<31)) - 1);
+
+ /*
+ * If there is only one slot occupied, or a segment was lost then
+ * an ACK is due after the last [good] segment left plus ack_delay
+ */
+
+ if (slot == first_slot && next_slot == ((first_slot + 1) % SEG_HIST_SIZE))
+ return (seg_hist[first_slot].ts + ack_delay + jitter);
+
+ if (seg_lost)
+ return (seg_hist[slot].ts + ack_delay + jitter);
+
+ /*
+ * OK, now, either we have only seen lost acks, or there are more than
+ * one outstanding segments, so figure out when the ACK is due.
+ *
+ * If delayed ACK is in force, ACK is due after every second seg, but
+ * if we had a lost ack, then we must ignore 2*lost_ack segments. So,
+ * if there has not been that many segments sent, we return infinity
+ * as the next ACK time
+ */
+
+ if (ack_lost) {
+ if (delayed_ack) {
+ if (((first_slot + 1 + 2 * ack_lost) % SEG_HIST_SIZE) >= next_slot)
+ /* XXX: FIXME, what about when the window is closed */
+ /* XXX: FIXME, use the correct value for this */
+ return (((unsigned int)(1<<31)) - 1);
+ else
+ return seg_hist[(first_slot + 1 + 2 * ack_lost) % SEG_HIST_SIZE].ts +
+ ack_delay + jitter;
+ }
+ else
+ return seg_hist[slot].ts + ack_delay + jitter;
+ }
+ else {
+ if (delayed_ack)
+ return (seg_hist[(first_slot + 1)%SEG_HIST_SIZE].ts+ack_delay+jitter);
+ else
+ return (seg_hist[first_slot].ts+ack_delay+jitter);
+ }
+}
+
+/*
+ * Update the relevant info of the sent seg
+ */
+add_seg_sent(int seq, int len)
+{
+
+ /*
+ * Should check we have not wrapped around and run into the unacked
+ * stuff ...
+ */
+ /*if (next_slot == first_slot) ;*/
+
+ segment++;
+ seg_hist[next_slot].seq_num = seq;
+ seg_hist[next_slot].len = len;
+ seg_hist[next_slot].ts = ts;
+ seg_hist[next_slot].seg_num = segment;
+ seg_hist[next_slot].flags = 0;
+ seg_hist[next_slot].acks_first_seq = 0;
+ used_win = used_win + len; /* Update the window used */
+
+ /*
+ * Now, update next_slot ...
+ */
+
+ next_slot = (next_slot + 1) % SEG_HIST_SIZE;
+
+}
+
+/*
+ * Generate the next ack based on the above reasoning ...
+ */
+
+#define NO_FORCE_ACK 0
+#define FORCE_ACK 1
+
+/*
+ * Generate the next ACK. If we did not generate an ACK, return 0,
+ * else return 1.
+ */
+int
+gen_next_ack(int force, int spacing)
+{
+ int seq_to_ack, new_ts, data_acked;
+
+ /*
+ * We need to check if the segment that we are about to generate an
+ * ack for is a segment that should be dropped ... or an ack that should
+ * be dropped.
+ *
+ * Figure out what we are doing before freeing segments ...
+ */
+
+ seq_to_ack = seg_hist[first_slot].seq_num + seg_hist[first_slot].len;
+ used_win = used_win - seg_hist[first_slot].len;
+ data_acked = seg_hist[first_slot].len;
+ new_ts = seg_hist[first_slot].ts + ack_delay;
+ first_slot = (first_slot + 1) % SEG_HIST_SIZE;
+
+ /*
+ * If delayed ACK in force, then ACK the next segment if there is one
+ */
+ if (delayed_ack && (first_slot != next_slot)) {
+ seq_to_ack += seg_hist[first_slot].len;
+ used_win = used_win - seg_hist[first_slot].len;
+ data_acked += seg_hist[first_slot].len;
+ new_ts = seg_hist[first_slot].ts + ack_delay;
+ first_slot = (first_slot + 1) % SEG_HIST_SIZE;
+ }
+
+ /*
+ * We don't want time to go backward ...
+ */
+ if (new_ts + jitter <= ts)
+ ts++;
+ else
+ ts = new_ts + jitter;
+
+ jitter = (rand() % 10 - 5); /* Update jitter ... */
+
+ makeseg(eth_2, eth_1, ip_2, ip_1, port_2, port_1, &seq_2, &seq_to_ack, "10", 0);
+ /*
+ * Do we want the exponential part or the linear part?
+ */
+ if (cwnd >= ssthresh)
+ cwnd += (1460*data_acked)/cwnd; /* is this right? */
+ else
+ cwnd = cwnd + data_acked;
+ if (verbose) fprintf(stderr, "Ack rcvd. ts: %d, data_acked: %d, cwnd: %d, window: %d\n",
+ ts, data_acked, cwnd, window);
+ if (cwnd > window) cwnd = window;
+}
+
+void
+makeackedrun(int len, int spacing, int ackdelay)
+{
+ int old_seq1, next_ack_ts=0;
+ if (verbose) fprintf(stderr, "makeackedrun: Len=%d, spacing=%d, ackdelay=%d\n",
+ len, spacing, ackdelay);
+ old_seq1=seq_1;
+ while(len>0){
+
+ /*
+ * Each time we output a segment, we should check to see if an
+ * ack is due back before the next segment is due ...
+ */
+ int seglen, saved_seq;
+ seglen=(len>1460)?1460:len;
+ /*
+ * Only output what is left in the cwnd.
+ * We assume there is space in the congestion window here
+ */
+ if (seglen > (cwnd - used_win)) seglen = cwnd - used_win;
+
+ len-=seglen;
+ saved_seq = seq_1;
+ if (verbose) fprintf(stderr, "Sending segment. ts: %d, jitter: %d\n", ts, jitter);
+ if(len){
+ makeseg(eth_1, eth_2, ip_1, ip_2, port_1, port_2, &seq_1, &seq_2, "10", seglen);
+ } else {
+ makeseg(eth_1, eth_2, ip_1, ip_2, port_1, port_2, &seq_1, &seq_2, "18", seglen);
+ }
+ add_seg_sent(saved_seq, seglen);
+
+ /*
+ * Now, if the window is closed, then we have to eject an
+ * ack, otherwise we can eject more data.
+ * Also, the other end will tend to ack two segments at
+ * a time ... and that ack might fall between two
+ * outgoing segments
+ */
+ jitter = (rand()%10) - 5; /* What if spacing too small */
+
+ if (verbose) fprintf(stderr, "used win: %d, cwnd: %d\n", used_win, cwnd);
+
+ if ((next_ack_ts = next_ack_due()) < ts + spacing + jitter) {
+ int old_ts = ts;
+
+ /*
+ * Generate the ack and retire the segments
+ * If delayed ACK in use, there should be two
+ * or more outstanding segments ...
+ */
+ if (verbose) fprintf(stderr, "Non forced ACK ...ts + spacing + jitter:%d, jitter: %d\n", ts + spacing + jitter, jitter);
+ gen_next_ack(NO_FORCE_ACK, spacing);
+ /*
+ * We don't want time to go backwards ...
+ */
+ if (old_ts + spacing + jitter <= ts)
+ ts++;
+ else
+ ts = old_ts + spacing + jitter;
+
+ } else if (used_win == cwnd) {
+
+ /*
+ * We need an ACK, so generate it and retire the
+ * segments and advance the ts to the time of the ack
+ */
+
+ if (verbose) fprintf(stderr, "Forced ACK ... \n");
+ gen_next_ack(FORCE_ACK, spacing);
+
+ ts+=(spacing+jitter); /* Should not use spacing here */
+
+ }
+ else {
+ ts+=(spacing+jitter);
+ }
+
+ if (verbose) fprintf(stderr, "Next Ack Due: %d\n", next_ack_ts);
+ }
+
+}
+
+
+void
+makeackedrundroppedtail8kb(int len, int spacing, int ackdelay)
+{
+ int old_seq1;
+ int dropped_tail;
+ int i;
+ int num_dupes;
+ if (verbose) fprintf(stderr, "makeackedrundroppedtail8kB: Len=%d, spacing=%d, ackdelay=%d\n",
+ len, spacing, ackdelay);
+ old_seq1=seq_1;
+ while(len>0){
+ int seglen;
+ seglen=(len>1460)?1460:len;
+ len-=seglen;
+ if(seglen==1460){
+ makeseg(eth_1, eth_2, ip_1, ip_2, port_1, port_2, &seq_1, &seq_2, "10", seglen);
+ } else {
+ makeseg(eth_1, eth_2, ip_1, ip_2, port_1, port_2, &seq_1, &seq_2, "18", seglen);
+ }
+ ts+=spacing;
+ }
+
+ ts+=ackdelay;
+
+ i=0;
+ num_dupes=-1;
+ dropped_tail=0;
+ while(old_seq1!=seq_1){
+ int ack_len;
+
+ ack_len=((seq_1-old_seq1)>2920)?2920:(seq_1-old_seq1);
+
+ i++;
+ if(i==6){
+ dropped_tail=old_seq1;
+ }
+ old_seq1+=ack_len;
+ if(i<6){
+ makeseg(eth_2, eth_1, ip_2, ip_1, port_2, port_1, &seq_2, &old_seq1, "10", 0);
+ } else if (i==6) {
+ makeseg(eth_2, eth_1, ip_2, ip_1, port_2, port_1, &seq_2, &dropped_tail, "10", 0);
+ num_dupes+=2;
+ } else {
+ makeseg(eth_2, eth_1, ip_2, ip_1, port_2, port_1, &seq_2, &dropped_tail, "10", 0);
+ makeseg(eth_2, eth_1, ip_2, ip_1, port_2, port_1, &seq_2, &dropped_tail, "10", 0);
+ num_dupes+=2;
+ }
+ ts+=spacing/2;
+ }
+
+ if(!dropped_tail){
+ return;
+ }
+
+ if(num_dupes<3){
+ int seglen;
+ int new_seq;
+ ts+=1000000;
+ seglen=((seq_1-dropped_tail)>1460)?1460:(seq_1-dropped_tail);
+ if(seglen==1460){
+ makeseg(eth_1, eth_2, ip_1, ip_2, port_1, port_2, &dropped_tail, &seq_2, "10", seglen);
+ } else {
+ makeseg(eth_1, eth_2, ip_1, ip_2, port_1, port_2, &dropped_tail, &seq_2, "18", seglen);
+ }
+ ts+=ackdelay;
+
+ new_seq=seglen+seq_1;
+ makeseg(eth_2, eth_1, ip_2, ip_1, port_2, port_1, &seq_2, &seq_1, "10", 0);
+ ts+=spacing;
+ return;
+ }
+
+ while(dropped_tail!=seq_1){
+ int seglen;
+ int ack;
+ seglen=((seq_1-dropped_tail)>1460)?1460:(seq_1-dropped_tail);
+ if(seglen==1460){
+ makeseg(eth_1, eth_2, ip_1, ip_2, port_1, port_2, &dropped_tail, &seq_2, "10", seglen);
+ } else {
+ makeseg(eth_1, eth_2, ip_1, ip_2, port_1, port_2, &dropped_tail, &seq_2, "18", seglen);
+ }
+ ts+=ackdelay;
+
+ ack=dropped_tail;
+ makeseg(eth_2, eth_1, ip_2, ip_1, port_2, port_1, &seq_2, &ack, "10", 0);
+ ts+=spacing;
+ }
+}
+
+void usage()
+{
+ fprintf(stderr, "Usage: mkcap [OPTIONS], where\n");
+ fprintf(stderr, "\t-a <ack-delay> is the delay to an ACK (RTT)\n");
+ fprintf(stderr, "\t-b <bytes-to-send> is the bytes to send on connection\n");
+ fprintf(stderr, "\t-i <ip-addr-hex> is the sender IP address in hex\n");
+ fprintf(stderr, "\t-I <ip-addr-hex> is the recipient IP address in hex\n");
+ fprintf(stderr, "\t-n <ISN> is almost the ISN for the sender\n");
+ fprintf(stderr, "\t-N <ISN> is almost the ISN for the recipient\n");
+ fprintf(stderr, "\t-p <port-number-hex> is the port number for sender\n");
+ fprintf(stderr, "\t-P <port-number-hex> is the port number for recipient\n");
+ fprintf(stderr, "\t-s <send-spacing> is the send spacing\n");
+ fprintf(stderr, "\t-w <window-size> is the window size\n");
+}
+
+int
+all_digits(char *str)
+{
+ int i;
+ if (!str || !(*str)) {
+ return 0;
+ }
+
+ for (i = 0; str[i]; i++) {
+ if (!isdigit(str[i]))
+ return 0;
+ }
+
+ return 1;
+}
+
+/*
+ * Process a list of drops. These are of the form:
+ *
+ * first_seg,seg_count[,first_seg,seg_count]*
+ */
+void
+process_drop_list(char *drop_list)
+{
+ int commas=0, i;
+ char *tok, *save;
+
+ if (!drop_list || !(*drop_list)) {
+ fprintf(stderr, "Strange drop list. NULL or an empty string. No drops!\n");
+ return;
+ }
+ save = (char *)strdup(drop_list);
+
+ for (tok=(char *)strtok(drop_list, ","); tok; tok=(char *)strtok(NULL, ",")) {
+ commas++;
+ }
+
+ /* Now, we have commas, divide by two and round up */
+
+ seg_drop_count = (commas+1)/2;
+ drops = (seg_drop_t *)malloc(sizeof(seg_drop_t) * seg_drop_count);
+ if (!drops) {
+ fprintf(stderr, "Unable to allocate space for drops ... going without!\n");
+ seg_drop_count = 0;
+ free(save);
+ return;
+ }
+
+ /* Now, go through the list again and build the drop list. Any errors and */
+ /* we abort and print a usage message */
+
+ commas = 0;
+ for (tok=(char *)strtok(save, ","); tok; tok=(char *)strtok(NULL, ",")) {
+ int num = atoi(tok);
+
+ if (!all_digits(tok)) {
+ fprintf(stderr, "Error in segment offset or count. Not all digits: %s\n",
+ tok);
+ fprintf(stderr, "No packet drops being performed!\n");
+ free(save);
+ free(drops);
+ seg_drop_count = 0; drops = NULL;
+ return;
+ }
+ if (num == 0) num = 1;
+ if (commas % 2)
+ drops[commas / 2].drop_seg_count = num;
+ else
+ drops[commas / 2].drop_seg_start = num;
+ }
+
+
+
+}
+
+int
+main(int argc, char *argv[])
+{
+ int i;
+ int len;
+ int type;
+ int cnt;
+ extern char *optarg;
+ extern int optind;
+ int opt;
+
+ while ((opt = getopt(argc, argv, "a:b:d:Di:I:j:l:n:N:p:P:r:s:vw:")) != EOF) {
+ switch (opt) {
+ case 'a':
+ ack_delay = atoi(optarg);
+ break;
+
+ case 'b': /* Bytes ... */
+ total_bytes = atoi(optarg);
+ break;
+
+ case 'd': /* A list of drops to simulate */
+ process_drop_list(optarg);
+ break;
+
+ case 'D': /* Toggle tcp_nodelay */
+ tcp_nodelay = (tcp_nodelay + 1) % 1;
+ break;
+
+ case 'i':
+ ip_1 = optarg;
+ break;
+
+ case 'I':
+ ip_2 = optarg;
+ break;
+
+ case 'l':
+ snap_len = atoi(optarg);
+ break;
+
+ case 'n': /* ISN for send dirn, ie, seq_1 */
+ seq_1 = atoi(optarg);
+ break;
+
+ case 'N': /* ISN for recv dirn, ie, seq_2 */
+ seq_2 = atoi(optarg);
+ break;
+
+ case 'p':
+ port_1 = optarg;
+ break;
+
+ case 'P':
+ port_2 = optarg;
+ break;
+
+ case 'r':
+ run_type = atoi(optarg);
+ break;
+
+ case 's':
+ send_spacing = atoi(optarg);
+ break;
+
+ case 'v':
+ verbose++;
+ break;
+
+ case 'w': /* Window ... */
+ window = atoi(optarg);
+ ssthresh = window / 2; /* Have to recalc this ... */
+ break;
+
+ default:
+ usage();
+ break;
+ }
+ }
+
+ if (verbose) fprintf(stderr, "IP1: %s, IP2: %s, P1: %s, P2: %s, Ack Delay: %d, Send Spacing: %d\n",
+ ip_1, ip_2, port_1, port_2, ack_delay, send_spacing);
+
+ /*return 0; */
+
+ if (run_type == 0) {
+ makeackedrun(total_bytes, send_spacing, ack_delay);
+ }
+ else {
+ for(cnt=0;cnt<200;cnt++){
+ type=rand()%150;
+ if(type<75){
+ int j;
+ j=5+rand()%10;
+ for(i=0;i<j;i++){
+ makeackedrun(32768, send_spacing, ack_delay);
+ }
+ } else if(type<90) {
+ int j;
+ j=4+rand()%4;
+ for(i=0;i<j;i++){
+ len=100+rand()&0xfff;
+ makeackedrun(len, send_spacing, ack_delay);
+ }
+ } else {
+ for(i=0;i<5;i++){
+ len=100+rand()&0x3fff+0x1fff;
+ makeackedrun(len, send_spacing, ack_delay);
+ /*makeackedrundroppedtail8kb(len, send_spacing, ack_delay);*/
+ }
+ }
+ }
+ }
+ return 0;
+}
+
git.samba.org / metze / wireshark / wip.git / commitdiff