* Parse TCP options and place in tcpopt. */
| 3413 | * Parse TCP options and place in tcpopt. |
| 3414 | */ |
| 3415 | void |
| 3416 | tcp_dooptions(struct tcpopt *to, u_char *cp, int cnt, int flags) |
| 3417 | { |
| 3418 | int opt, optlen; |
| 3419 | |
| 3420 | to->to_flags = 0; |
| 3421 | for (; cnt > 0; cnt -= optlen, cp += optlen) { |
| 3422 | opt = cp[0]; |
| 3423 | if (opt == TCPOPT_EOL) |
| 3424 | break; |
| 3425 | if (opt == TCPOPT_NOP) |
| 3426 | optlen = 1; |
| 3427 | else { |
| 3428 | if (cnt < 2) |
| 3429 | break; |
| 3430 | optlen = cp[1]; |
| 3431 | if (optlen < 2 || optlen > cnt) |
| 3432 | break; |
| 3433 | } |
| 3434 | switch (opt) { |
| 3435 | case TCPOPT_MAXSEG: |
| 3436 | if (optlen != TCPOLEN_MAXSEG) |
| 3437 | continue; |
| 3438 | if (!(flags & TO_SYN)) |
| 3439 | continue; |
| 3440 | to->to_flags |= TOF_MSS; |
| 3441 | bcopy((char *)cp + 2, |
| 3442 | (char *)&to->to_mss, sizeof(to->to_mss)); |
| 3443 | to->to_mss = ntohs(to->to_mss); |
| 3444 | break; |
| 3445 | case TCPOPT_WINDOW: |
| 3446 | if (optlen != TCPOLEN_WINDOW) |
| 3447 | continue; |
| 3448 | if (!(flags & TO_SYN)) |
| 3449 | continue; |
| 3450 | to->to_flags |= TOF_SCALE; |
| 3451 | to->to_wscale = min(cp[2], TCP_MAX_WINSHIFT); |
| 3452 | break; |
| 3453 | case TCPOPT_TIMESTAMP: |
| 3454 | if (optlen != TCPOLEN_TIMESTAMP) |
| 3455 | continue; |
| 3456 | to->to_flags |= TOF_TS; |
| 3457 | bcopy((char *)cp + 2, |
| 3458 | (char *)&to->to_tsval, sizeof(to->to_tsval)); |
| 3459 | to->to_tsval = ntohl(to->to_tsval); |
| 3460 | bcopy((char *)cp + 6, |
| 3461 | (char *)&to->to_tsecr, sizeof(to->to_tsecr)); |
| 3462 | to->to_tsecr = ntohl(to->to_tsecr); |
| 3463 | break; |
| 3464 | case TCPOPT_SIGNATURE: |
| 3465 | /* |
| 3466 | * In order to reply to a host which has set the |
| 3467 | * TCP_SIGNATURE option in its initial SYN, we have |
| 3468 | * to record the fact that the option was observed |
| 3469 | * here for the syncache code to perform the correct |
| 3470 | * response. |
| 3471 | */ |
| 3472 | if (optlen != TCPOLEN_SIGNATURE) |
no test coverage detected