From: Guy Harris Date: Thu, 12 Jul 2018 18:49:28 +0000 (-0700) Subject: DLT_LINUX_SLL2 support. X-Git-Tag: tcpdump-4.99-bp~1102 X-Git-Url: https://git.tcpdump.org/tcpdump/commitdiff_plain/51c1da63e40e046b6b4620edb1ac1ba8b2707182 DLT_LINUX_SLL2 support. --- diff --git a/netdissect.h b/netdissect.h index 4f3c666a..93fa8be6 100644 --- a/netdissect.h +++ b/netdissect.h @@ -465,6 +465,7 @@ extern u_int raw_if_print IF_PRINTER_ARGS; extern u_int sl_bsdos_if_print IF_PRINTER_ARGS; extern u_int sl_if_print IF_PRINTER_ARGS; extern u_int sll_if_print IF_PRINTER_ARGS; +extern u_int sll2_if_print IF_PRINTER_ARGS; extern u_int sunatm_if_print IF_PRINTER_ARGS; extern u_int symantec_if_print IF_PRINTER_ARGS; extern u_int token_if_print IF_PRINTER_ARGS; diff --git a/print-sll.c b/print-sll.c index 571b7c5e..5a4e2f68 100644 --- a/print-sll.c +++ b/print-sll.c @@ -84,6 +84,21 @@ struct sll_header { nd_uint16_t sll_protocol; /* protocol */ }; +/* + * A DLT_LINUX_SLL2 fake link-layer header. + */ +#define SLL2_HDR_LEN 20 /* total header length */ + +struct sll2_header { + nd_uint16_t sll2_protocol; /* protocol */ + nd_uint16_t sll2_reserved_mbz; /* reserved - must be zero */ + nd_uint32_t sll2_if_index; /* 1-based interface index */ + nd_uint16_t sll2_hatype; /* link-layer address type */ + nd_uint8_t sll2_pkttype; /* packet type */ + nd_uint8_t sll2_halen; /* link-layer address length */ + nd_byte sll2_addr[SLL_ADDRLEN]; /* link-layer address */ +}; + /* * The LINUX_SLL_ values for "sll_pkttype"; these correspond to the * PACKET_ values on Linux, but are defined here so that they're @@ -308,3 +323,183 @@ recurse: return (hdrlen); } + +static void +sll2_print(netdissect_options *ndo, const struct sll2_header *sllp, u_int length) +{ + u_short ether_type; + + ndo->ndo_protocol = "sll2"; + ND_PRINT("%3s ",tok2str(sll_pkttype_values,"?",EXTRACT_BE_U_2(sllp->sll2_pkttype))); + + /* + * XXX - check the link-layer address type value? + * For now, we just assume 6 means Ethernet. + * XXX - print others as strings of hex? + */ + if (EXTRACT_U_1(sllp->sll2_halen) == 6) + ND_PRINT("%s ", etheraddr_string(ndo, sllp->sll2_addr)); + + if (!ndo->ndo_qflag) { + ether_type = EXTRACT_BE_U_2(sllp->sll2_protocol); + + if (ether_type <= MAX_ETHERNET_LENGTH_VAL) { + /* + * Not an Ethernet type; what type is it? + */ + switch (ether_type) { + + case LINUX_SLL_P_802_3: + /* + * Ethernet_802.3 IPX frame. + */ + ND_PRINT("802.3"); + break; + + case LINUX_SLL_P_802_2: + /* + * 802.2. + */ + ND_PRINT("802.2"); + break; + + default: + /* + * What is it? + */ + ND_PRINT("ethertype Unknown (0x%04x)", + ether_type); + break; + } + } else { + ND_PRINT("ethertype %s (0x%04x)", + tok2str(ethertype_values, "Unknown", ether_type), + ether_type); + } + ND_PRINT(", length %u: ", length); + } +} + +/* + * This is the top level routine of the printer. 'p' points to the + * Linux "cooked capture" header of the packet, 'h->ts' is the timestamp, + * 'h->len' is the length of the packet off the wire, and 'h->caplen' + * is the number of bytes actually captured. + */ +u_int +sll2_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p) +{ + u_int caplen = h->caplen; + u_int length = h->len; + const struct sll2_header *sllp; + u_short ether_type; + int llc_hdrlen; + u_int hdrlen; + + ndo->ndo_protocol = "sll2_if"; + if (caplen < SLL2_HDR_LEN) { + /* + * XXX - this "can't happen" because "pcap-linux.c" always + * adds this many bytes of header to every packet in a + * cooked socket capture. + */ + nd_print_trunc(ndo); + return (caplen); + } + + sllp = (const struct sll2_header *)p; + + if (ndo->ndo_eflag) + sll2_print(ndo, sllp, length); + + /* + * Go past the cooked-mode header. + */ + length -= SLL2_HDR_LEN; + caplen -= SLL2_HDR_LEN; + p += SLL2_HDR_LEN; + hdrlen = SLL2_HDR_LEN; + + ether_type = EXTRACT_BE_U_2(sllp->sll2_protocol); + +recurse: + /* + * Is it (gag) an 802.3 encapsulation, or some non-Ethernet + * packet type? + */ + if (ether_type <= MAX_ETHERNET_LENGTH_VAL) { + /* + * Yes - what type is it? + */ + switch (ether_type) { + + case LINUX_SLL_P_802_3: + /* + * Ethernet_802.3 IPX frame. + */ + ipx_print(ndo, p, length); + break; + + case LINUX_SLL_P_802_2: + /* + * 802.2. + * Try to print the LLC-layer header & higher layers. + */ + llc_hdrlen = llc_print(ndo, p, length, caplen, NULL, NULL); + if (llc_hdrlen < 0) + goto unknown; /* unknown LLC type */ + hdrlen += llc_hdrlen; + break; + + default: + /*FALLTHROUGH*/ + + unknown: + /* packet type not known, print raw packet */ + if (!ndo->ndo_suppress_default_print) + ND_DEFAULTPRINT(p, caplen); + break; + } + } else if (ether_type == ETHERTYPE_8021Q) { + /* + * Print VLAN information, and then go back and process + * the enclosed type field. + */ + if (caplen < 4) { + ND_PRINT("[|vlan]"); + return (hdrlen + caplen); + } + if (length < 4) { + ND_PRINT("[|vlan]"); + return (hdrlen + length); + } + if (ndo->ndo_eflag) { + uint16_t tag = EXTRACT_BE_U_2(p); + + ND_PRINT("%s, ", ieee8021q_tci_string(tag)); + } + + ether_type = EXTRACT_BE_U_2(p + 2); + if (ether_type <= MAX_ETHERNET_LENGTH_VAL) + ether_type = LINUX_SLL_P_802_2; + if (!ndo->ndo_qflag) { + ND_PRINT("ethertype %s, ", + tok2str(ethertype_values, "Unknown", ether_type)); + } + p += 4; + length -= 4; + caplen -= 4; + hdrlen += 4; + goto recurse; + } else { + if (ethertype_print(ndo, ether_type, p, length, caplen, NULL, NULL) == 0) { + /* ether_type not known, print raw packet */ + if (!ndo->ndo_eflag) + sll2_print(ndo, sllp, length + SLL_HDR_LEN); + if (!ndo->ndo_suppress_default_print) + ND_DEFAULTPRINT(p, caplen); + } + } + + return (hdrlen); +} diff --git a/print.c b/print.c index b9c92adc..4cc35bab 100644 --- a/print.c +++ b/print.c @@ -126,6 +126,9 @@ static const struct printer printers[] = { #ifdef DLT_LINUX_SLL { sll_if_print, DLT_LINUX_SLL }, #endif +#ifdef DLT_LINUX_SLL2 + { sll2_if_print, DLT_LINUX_SLL2 }, +#endif #ifdef DLT_FR { fr_if_print, DLT_FR }, #endif