67 lines
1.8 KiB
C
67 lines
1.8 KiB
C
/*
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* Utility routines.
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*
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* Copyright (C) 2018 Denys Vlasenko
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*
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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//kbuild:lib-$(CONFIG_FTPGET) += parse_pasv_epsv.o
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//kbuild:lib-$(CONFIG_FTPPUT) += parse_pasv_epsv.o
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//kbuild:lib-$(CONFIG_WGET) += parse_pasv_epsv.o
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#include "libbb.h"
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int FAST_FUNC parse_pasv_epsv(char *buf)
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{
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/*
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* PASV command will not work for IPv6. RFC2428 describes
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* IPv6-capable "extended PASV" - EPSV.
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*
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* "EPSV [protocol]" asks server to bind to and listen on a data port
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* in specified protocol. Protocol is 1 for IPv4, 2 for IPv6.
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* If not specified, defaults to "same as used for control connection".
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* If server understood you, it should answer "229 <some text>(|||port|)"
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* where "|" are literal pipe chars and "port" is ASCII decimal port#.
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*
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* There is also an IPv6-capable replacement for PORT (EPRT),
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* but we don't need that.
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*
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* NB: PASV may still work for some servers even over IPv6.
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* For example, vsftp happily answers
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* "227 Entering Passive Mode (0,0,0,0,n,n)" and proceeds as usual.
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*/
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char *ptr;
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int port;
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if (!ENABLE_FEATURE_IPV6 || buf[2] == '7' /* "227" */) {
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/* Response is "227 garbageN1,N2,N3,N4,P1,P2[)garbage]"
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* Server's IP is N1.N2.N3.N4 (we ignore it)
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* Server's port for data connection is P1*256+P2 */
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ptr = strrchr(buf, ')');
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if (ptr) *ptr = '\0';
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ptr = strrchr(buf, ',');
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if (!ptr) return -1;
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*ptr = '\0';
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port = xatou_range(ptr + 1, 0, 255);
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ptr = strrchr(buf, ',');
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if (!ptr) return -1;
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*ptr = '\0';
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port += xatou_range(ptr + 1, 0, 255) * 256;
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} else {
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/* Response is "229 garbage(|||P1|)"
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* Server's port for data connection is P1 */
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ptr = strrchr(buf, '|');
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if (!ptr) return -1;
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*ptr = '\0';
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ptr = strrchr(buf, '|');
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if (!ptr) return -1;
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*ptr = '\0';
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port = xatou_range(ptr + 1, 0, 65535);
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}
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return port;
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}
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