Make tcpdump understand the T/TCP (RFC-1644) options. Some extra sanity
checks were also introduced to the tcp_print function so it doesn't try to interpret TCP options beyond the length of the sniffed packet.
This commit is contained in:
Andras Olah
parent
cafb7c1233
commit
9520a7526d
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=6957
@ -21,7 +21,7 @@
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#ifndef lint
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static char rcsid[] =
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"@(#) $Header: print-tcp.c,v 1.28 94/06/16 01:26:40 mccanne Exp $ (LBL)";
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"@(#) $Header: /home/ncvs/src/usr.sbin/tcpdump/tcpdump/print-tcp.c,v 1.2 1995/03/08 12:52:44 olah Exp $ (LBL)";
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#endif
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#include <sys/param.h>
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@ -62,6 +62,39 @@ static char rcsid[] =
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#ifndef TCPOPT_TIMESTAMP
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#define TCPOPT_TIMESTAMP 8 /* timestamps (rfc1323) */
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#endif
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#ifndef TCPOPT_CC
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#define TCPOPT_CC 11 /* connection count (rfc1644) */
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#endif
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#ifndef TCPOPT_CCNEW
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#define TCPOPT_CCNEW 12 /* connection count new (rfc1644) */
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#endif
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#ifndef TCPOPT_CCECHO
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#define TCPOPT_CCECHO 13 /* connection count echo (rfc1644) */
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#endif
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struct opt_table {
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int len; /* option length, zero if unknown */
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const char *nam; /* option name */
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};
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static struct opt_table tcp_opts[] = {
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{ 1, "eol" },
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{ 1, "nop" },
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{ 4, "mss" },
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{ 3, "wscale" },
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{ 2, "sackOK" },
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{ 0, "sack" }, /* XXX sack: don't know how long */
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{ 6, "echo" },
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{ 6, "echoreply" },
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{10, "timestamp" },
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{ 0, "opt-%d:" },
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{ 0, "opt-%d:" },
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{ 6, "cc" },
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{ 6, "ccnew" },
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{ 6, "ccecho" },
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{ 0, "opt-%d:" }, /* last entry must be an unknown option */
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};
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#define MAXTCPOPT (sizeof(tcp_opts)/sizeof(tcp_opts[0])-1)
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struct tha {
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struct in_addr src;
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@ -193,84 +226,82 @@ tcp_print(register const u_char *bp, register int length,
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register const u_char *cp = (const u_char *)tp + sizeof(*tp);
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int i;
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char ch = '<';
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char lch = '>';
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putchar(' ');
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while (--hlen >= 0) {
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/* adjust length if necessary */
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if (cp + hlen > snapend) {
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hlen = snapend - cp;
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lch = '|';
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}
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while (hlen > 0) {
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register struct opt_table *opt;
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putchar(ch);
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switch (*cp++) {
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case TCPOPT_MAXSEG:
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{
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(void)printf("mss %d", cp[1] << 8 | cp[2]);
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if (*cp != 4)
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(void)printf("[len %d]", *cp);
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cp += 3;
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hlen -= 3;
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ch = ',';
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opt = *cp < MAXTCPOPT ?
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&tcp_opts[*cp] : &tcp_opts[MAXTCPOPT];
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(void)printf(opt->nam, *cp);
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/* eol and nop have no length */
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if (opt->len == 1) {
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hlen--, cp++;
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continue;
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}
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/* quit if options are truncated */
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if ((hlen == 1) ||
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(opt->len != 0 && hlen < opt->len) ||
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(opt->len == 0 && hlen < *(cp + 1))) {
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lch = '|';
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break;
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}
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case TCPOPT_EOL:
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(void)printf("eol");
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break;
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case TCPOPT_NOP:
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(void)printf("nop");
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/* check if optlen in segment is what we assume */
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if (opt->len != 0 && *(cp + 1) != opt->len) {
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register int l = *(cp + 1);
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(void)printf("[len %d]", l);
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hlen -= l;
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cp += l;
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continue;
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}
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/* print the option body */
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switch (*cp) {
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case TCPOPT_MAXSEG:
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(void)printf(" %d", cp[2] << 8 | cp[3]);
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break;
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case TCPOPT_WSCALE:
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(void)printf("wscale %d", cp[1]);
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if (*cp != 3)
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(void)printf("[len %d]", *cp);
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cp += 2;
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hlen -= 2;
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(void)printf(" %d", cp[2]);
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break;
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case TCPOPT_SACKOK:
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(void)printf("sackOK");
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if (*cp != 2)
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(void)printf("[len %d]", *cp);
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cp += 1;
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hlen -= 1;
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break;
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case TCPOPT_ECHO:
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{
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(void)printf("echo %u",
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cp[1] << 24 | cp[2] << 16 |
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cp[3] << 8 | cp[4]);
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if (*cp != 6)
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(void)printf("[len %d]", *cp);
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cp += 5;
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hlen -= 5;
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break;
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}
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case TCPOPT_ECHOREPLY:
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{
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(void)printf("echoreply %u",
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cp[1] << 24 | cp[2] << 16 |
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cp[3] << 8 | cp[4]);
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if (*cp != 6)
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(void)printf("[len %d]", *cp);
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cp += 5;
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hlen -= 5;
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case TCPOPT_CC:
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case TCPOPT_CCNEW:
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case TCPOPT_CCECHO:
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(void)printf(" %lu",
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cp[2] << 24 | cp[3] << 16 |
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cp[4] << 8 | cp[5]);
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break;
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}
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case TCPOPT_TIMESTAMP:
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{
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(void)printf("timestamp %lu %lu",
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cp[1] << 24 | cp[2] << 16 |
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cp[3] << 8 | cp[4],
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cp[5] << 24 | cp[6] << 16 |
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cp[7] << 8 | cp[8]);
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if (*cp != 10)
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(void)printf("[len %d]", *cp);
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cp += 9;
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hlen -= 9;
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(void)printf(" %lu %lu",
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cp[2] << 24 | cp[3] << 16 |
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cp[4] << 8 | cp[5],
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cp[6] << 24 | cp[7] << 16 |
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cp[8] << 8 | cp[9]);
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break;
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}
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default:
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(void)printf("opt-%d:", cp[-1]);
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for (i = *cp++ - 2, hlen -= i + 1; i > 0; --i)
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hlen -= *++cp;
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for (i = *cp++ - 2; i > 0; --i)
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(void)printf("%02x", *cp++);
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break;
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}
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ch = ',';
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/* adjust length */
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hlen -= opt->len;
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cp += opt->len;
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}
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putchar('>');
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putchar(lch);
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}
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}
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