X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/f91b36d2a0fdd2d5f75564d495de562eed5d7a63..refs/pull/435/head:/util.c diff --git a/util.c b/util.c index 3836151c..5569021c 100644 --- a/util.c +++ b/util.c @@ -19,6 +19,22 @@ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. */ +/* + * txtproto_print() derived from original code by Hannes Gredler + * (hannes@juniper.net): + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that: (1) source code + * distributions retain the above copyright notice and this paragraph + * in its entirety, and (2) distributions including binary code include + * the above copyright notice and this paragraph in its entirety in + * the documentation or other materials provided with the distribution. + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND + * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT + * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE. + */ + #define NETDISSECT_REWORKED #ifdef HAVE_CONFIG_H #include "config.h" @@ -475,6 +491,249 @@ mask62plen(const u_char *mask) } #endif /* INET6 */ +/* + * Routine to print out information for text-based protocols such as FTP, + * HTTP, SMTP, RTSP, SIP, .... + */ +#define MAX_TOKEN 128 + +/* + * Fetch a token from a packet, starting at the specified index, + * and return the length of the token. + * + * Returns 0 on error; yes, this is indistinguishable from an empty + * token, but an "empty token" isn't a valid token - it just means + * either a space character at the beginning of the line (this + * includes a blank line) or no more tokens remaining on the line. + */ +static int +fetch_token(netdissect_options *ndo, const u_char *pptr, u_int idx, u_int len, + u_char *tbuf, size_t tbuflen) +{ + size_t toklen = 0; + + for (; idx < len; idx++) { + if (!ND_TTEST(*(pptr + idx))) { + /* ran past end of captured data */ + return (0); + } + if (!isascii(*(pptr + idx))) { + /* not an ASCII character */ + return (0); + } + if (isspace(*(pptr + idx))) { + /* end of token */ + break; + } + if (!isprint(*(pptr + idx))) { + /* not part of a command token or response code */ + return (0); + } + if (toklen + 2 > tbuflen) { + /* no room for this character and terminating '\0' */ + return (0); + } + tbuf[toklen] = *(pptr + idx); + toklen++; + } + if (toklen == 0) { + /* no token */ + return (0); + } + tbuf[toklen] = '\0'; + + /* + * Skip past any white space after the token, until we see + * an end-of-line (CR or LF). + */ + for (; idx < len; idx++) { + if (!ND_TTEST(*(pptr + idx))) { + /* ran past end of captured data */ + break; + } + if (*(pptr + idx) == '\r' || *(pptr + idx) == '\n') { + /* end of line */ + break; + } + if (!isascii(*(pptr + idx)) || !isprint(*(pptr + idx))) { + /* not a printable ASCII character */ + break; + } + if (!isspace(*(pptr + idx))) { + /* beginning of next token */ + break; + } + } + return (idx); +} + +/* + * Scan a buffer looking for a line ending - LF or CR-LF. + * Return the index of the character after the line ending or 0 if + * we encounter a non-ASCII or non-printable character or don't find + * the line ending. + */ +static u_int +print_txt_line(netdissect_options *ndo, const char *protoname, + const char *prefix, const u_char *pptr, u_int idx, u_int len) +{ + u_int startidx; + u_int linelen; + + startidx = idx; + while (idx < len) { + ND_TCHECK(*(pptr+idx)); + if (*(pptr+idx) == '\n') { + /* + * LF without CR; end of line. + * Skip the LF and print the line, with the + * exception of the LF. + */ + linelen = idx - startidx; + idx++; + goto print; + } else if (*(pptr+idx) == '\r') { + /* CR - any LF? */ + if ((idx+1) >= len) { + /* not in this packet */ + return (0); + } + ND_TCHECK(*(pptr+idx+1)); + if (*(pptr+idx+1) == '\n') { + /* + * CR-LF; end of line. + * Skip the CR-LF and print the line, with + * the exception of the CR-LF. + */ + linelen = idx - startidx; + idx += 2; + goto print; + } + + /* + * CR followed by something else; treat this + * as if it were binary data, and don't print + * it. + */ + return (0); + } else if (!isascii(*(pptr+idx)) || + (!isprint(*(pptr+idx)) && *(pptr+idx) != '\t')) { + /* + * Not a printable ASCII character and not a tab; + * treat this as if it were binary data, and + * don't print it. + */ + return (0); + } + idx++; + } + + /* + * All printable ASCII, but no line ending after that point + * in the buffer; treat this as if it were truncated. + */ +trunc: + linelen = idx - startidx; + ND_PRINT((ndo, "%s%.*s[!%s]", prefix, (int)linelen, pptr + startidx, + protoname)); + return (0); + +print: + ND_PRINT((ndo, "%s%.*s", prefix, (int)linelen, pptr + startidx)); + return (idx); +} + +void +txtproto_print(netdissect_options *ndo, const u_char *pptr, u_int len, + const char *protoname, const char **cmds, u_int flags) +{ + u_int idx, eol; + u_char token[MAX_TOKEN+1]; + const char *cmd; + int is_reqresp = 0; + const char *pnp; + + if (cmds != NULL) { + /* + * This protocol has more than just request and + * response lines; see whether this looks like a + * request or response. + */ + idx = fetch_token(ndo, pptr, 0, len, token, sizeof(token)); + if (idx != 0) { + /* Is this a valid request name? */ + while ((cmd = *cmds++) != NULL) { + if (strcasecmp((const char *)token, cmd) == 0) { + /* Yes. */ + is_reqresp = 1; + break; + } + } + + /* + * No - is this a valid response code (3 digits)? + * + * Is this token the response code, or is the next + * token the response code? + */ + if (flags & RESP_CODE_SECOND_TOKEN) { + /* + * Next token - get it. + */ + idx = fetch_token(ndo, pptr, idx, len, token, + sizeof(token)); + } + if (idx != 0) { + if (isdigit(token[0]) && isdigit(token[1]) && + isdigit(token[2]) && token[3] == '\0') { + /* Yes. */ + is_reqresp = 1; + } + } + } + } else { + /* + * This protocol has only request and response lines + * (e.g., FTP, where all the data goes over a + * different connection); assume the payload is + * a request or response. + */ + is_reqresp = 1; + } + + /* Capitalize the protocol name */ + for (pnp = protoname; *pnp != '\0'; pnp++) + ND_PRINT((ndo, "%c", toupper(*pnp))); + + if (is_reqresp) { + /* + * In non-verbose mode, just print the protocol, followed + * by the first line as the request or response info. + * + * In verbose mode, print lines as text until we run out + * of characters or see something that's not a + * printable-ASCII line. + */ + if (ndo->ndo_vflag) { + /* + * We're going to print all the text lines in the + * request or response; just print the length + * on the first line of the output. + */ + ND_PRINT((ndo, ", length: %u", len)); + for (idx = 0; + idx < len && (eol = print_txt_line(ndo, protoname, "\n\t", pptr, idx, len)) != 0; + idx = eol) + ; + } else { + /* + * Just print the first text line. + */ + print_txt_line(ndo, protoname, ": ", pptr, 0, len); + } + } +} + /* VARARGS */ void error(const char *fmt, ...)