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Diffstat (limited to 'print-nflog.c')
| -rw-r--r-- | print-nflog.c | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/print-nflog.c b/print-nflog.c new file mode 100644 index 0000000..1e75561 --- /dev/null +++ b/print-nflog.c @@ -0,0 +1,231 @@ +/* + * Copyright (c) 2013, Petar Alilovic, + * Faculty of Electrical Engineering and Computing, University of Zagreb + * All rights reserved + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * * Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND ANY + * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED + * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY + * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR + * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER + * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH + * DAMAGE. + */ + +/* \summary: DLT_NFLOG printer */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#include "netdissect-stdinc.h" + +#include "netdissect.h" +#include "extract.h" + +#ifdef DLT_NFLOG + +/* + * Structure of an NFLOG header and TLV parts, as described at + * https://www.tcpdump.org/linktypes/LINKTYPE_NFLOG.html + * + * The NFLOG header is big-endian. + * + * The TLV length and type are in host byte order. The value is either + * big-endian or is an array of bytes in some externally-specified byte + * order (text string, link-layer address, link-layer header, packet + * data, etc.). + */ +typedef struct nflog_hdr { + nd_uint8_t nflog_family; /* address family */ + nd_uint8_t nflog_version; /* version */ + nd_uint16_t nflog_rid; /* resource ID */ +} nflog_hdr_t; + +#define NFLOG_HDR_LEN sizeof(nflog_hdr_t) + +typedef struct nflog_tlv { + nd_uint16_t tlv_length; /* tlv length */ + nd_uint16_t tlv_type; /* tlv type */ + /* value follows this */ +} nflog_tlv_t; + +#define NFLOG_TLV_LEN sizeof(nflog_tlv_t) + +typedef struct nflog_packet_hdr { + nd_uint16_t hw_protocol; /* hw protocol */ + nd_uint8_t hook; /* netfilter hook */ + nd_byte pad[1]; /* padding to 32 bits */ +} nflog_packet_hdr_t; + +typedef struct nflog_hwaddr { + nd_uint16_t hw_addrlen; /* address length */ + nd_byte pad[2]; /* padding to 32-bit boundary */ + nd_byte hw_addr[8]; /* address, up to 8 bytes */ +} nflog_hwaddr_t; + +typedef struct nflog_timestamp { + nd_uint64_t sec; + nd_uint64_t usec; +} nflog_timestamp_t; + +/* + * TLV types. + */ +#define NFULA_PACKET_HDR 1 /* nflog_packet_hdr_t */ +#define NFULA_MARK 2 /* packet mark from skbuff */ +#define NFULA_TIMESTAMP 3 /* nflog_timestamp_t for skbuff's time stamp */ +#define NFULA_IFINDEX_INDEV 4 /* ifindex of device on which packet received (possibly bridge group) */ +#define NFULA_IFINDEX_OUTDEV 5 /* ifindex of device on which packet transmitted (possibly bridge group) */ +#define NFULA_IFINDEX_PHYSINDEV 6 /* ifindex of physical device on which packet received (not bridge group) */ +#define NFULA_IFINDEX_PHYSOUTDEV 7 /* ifindex of physical device on which packet transmitted (not bridge group) */ +#define NFULA_HWADDR 8 /* nflog_hwaddr_t for hardware address */ +#define NFULA_PAYLOAD 9 /* packet payload */ +#define NFULA_PREFIX 10 /* text string - null-terminated, count includes NUL */ +#define NFULA_UID 11 /* UID owning socket on which packet was sent/received */ +#define NFULA_SEQ 12 /* sequence number of packets on this NFLOG socket */ +#define NFULA_SEQ_GLOBAL 13 /* sequence number of pakets on all NFLOG sockets */ +#define NFULA_GID 14 /* GID owning socket on which packet was sent/received */ +#define NFULA_HWTYPE 15 /* ARPHRD_ type of skbuff's device */ +#define NFULA_HWHEADER 16 /* skbuff's MAC-layer header */ +#define NFULA_HWLEN 17 /* length of skbuff's MAC-layer header */ + +static const struct tok nflog_values[] = { + { AF_INET, "IPv4" }, + { AF_INET6, "IPv6" }, + { 0, NULL } +}; + +static void +nflog_hdr_print(netdissect_options *ndo, const nflog_hdr_t *hdr, u_int length) +{ + ND_PRINT("version %u, resource ID %u", + GET_U_1(hdr->nflog_version), GET_BE_U_2(hdr->nflog_rid)); + + if (!ndo->ndo_qflag) { + ND_PRINT(", family %s (%u)", + tok2str(nflog_values, "Unknown", + GET_U_1(hdr->nflog_family)), + GET_U_1(hdr->nflog_family)); + } else { + ND_PRINT(", %s", + tok2str(nflog_values, + "Unknown NFLOG (0x%02x)", + GET_U_1(hdr->nflog_family))); + } + + ND_PRINT(", length %u: ", length); +} + +void +nflog_if_print(netdissect_options *ndo, + const struct pcap_pkthdr *h, const u_char *p) +{ + const nflog_hdr_t *hdr = (const nflog_hdr_t *)p; + uint16_t size; + uint16_t h_size = NFLOG_HDR_LEN; + u_int caplen = h->caplen; + u_int length = h->len; + + ndo->ndo_protocol = "nflog"; + if (caplen < NFLOG_HDR_LEN) { + nd_print_trunc(ndo); + ndo->ndo_ll_hdr_len += caplen; + return; + } + ndo->ndo_ll_hdr_len += NFLOG_HDR_LEN; + + ND_TCHECK_SIZE(hdr); + if (GET_U_1(hdr->nflog_version) != 0) { + ND_PRINT("version %u (unknown)", GET_U_1(hdr->nflog_version)); + return; + } + + if (ndo->ndo_eflag) + nflog_hdr_print(ndo, hdr, length); + + p += NFLOG_HDR_LEN; + length -= NFLOG_HDR_LEN; + caplen -= NFLOG_HDR_LEN; + + while (length > 0) { + const nflog_tlv_t *tlv; + + /* We have some data. Do we have enough for the TLV header? */ + if (caplen < NFLOG_TLV_LEN) + goto trunc; /* No. */ + + tlv = (const nflog_tlv_t *) p; + ND_TCHECK_SIZE(tlv); + size = GET_HE_U_2(tlv->tlv_length); + if (size % 4 != 0) + size += 4 - size % 4; + + /* Is the TLV's length less than the minimum? */ + if (size < NFLOG_TLV_LEN) + goto trunc; /* Yes. Give up now. */ + + /* Do we have enough data for the full TLV? */ + if (caplen < size) + goto trunc; /* No. */ + + if (GET_HE_U_2(tlv->tlv_type) == NFULA_PAYLOAD) { + /* + * This TLV's data is the packet payload. + * Skip past the TLV header, and break out + * of the loop so we print the packet data. + */ + p += NFLOG_TLV_LEN; + h_size += NFLOG_TLV_LEN; + length -= NFLOG_TLV_LEN; + caplen -= NFLOG_TLV_LEN; + break; + } + + p += size; + h_size += size; + length -= size; + caplen -= size; + } + + switch (GET_U_1(hdr->nflog_family)) { + + case AF_INET: + ip_print(ndo, p, length); + break; + + case AF_INET6: + ip6_print(ndo, p, length); + break; + + default: + if (!ndo->ndo_eflag) + nflog_hdr_print(ndo, hdr, + length + NFLOG_HDR_LEN); + + if (!ndo->ndo_suppress_default_print) + ND_DEFAULTPRINT(p, caplen); + break; + } + + ndo->ndo_ll_hdr_len += h_size - NFLOG_HDR_LEN; + return; +trunc: + nd_print_trunc(ndo); + ndo->ndo_ll_hdr_len += h_size - NFLOG_HDR_LEN; +} + +#endif /* DLT_NFLOG */ |